Consulta: subjectFacets:"Virulence"
Registros recuperados: 77
Data/hora: 05/06/2024 07:28:11

Resistencia a pudrición de mazorca en poblaciones de maíz bajo mejoramiento participativo en el Altiplano de México
Provedor de dados: 32
Autores: Briones Reyes, Dolores.
Con el objeto de evaluar la resistencia genética a la pudrición de la mazorca de nueve ciclos de selección de cada una de tres poblaciones de maíz Chalqueño (Azul, Palomo y Crema), y de determinar la distribución y virulencia de las especies de hongos causantes de la pudrición, se colectaron 26 muestras de mazorcas con y sin síntomas de pudrición en tres zonas de los Estados de México, Tlaxcala y Puebla. La evaluación de la resistencia se hizo en tres localidades, utilizando la mezcla de 15 aislamientos colectados en la región Chalco-Juchitepec, que fueron inoculados en los jilotes entre 7 y 10 días después de la emisión de los estigmas. La severidad de la enfermedad se evaluó a la cosecha, utilizando la escala 1 a 5 de acuerdo al porcentaje de infección....
Tipo: Tesis
Palavras-chave: Ciclos de selección; Fusarium; Resistencia genética; Pudrición de mazorca; Virulencia; Maestría; Genética; Selection cycles; Genetic resistance; Ear rot; Virulence.
Ano: 2007
URL: http://hdl.handle.net/10521/1660

Interacción intraespecífica de aislamientos del hongo Zoophthora radicans en larvas de Plutella xylostella.
Provedor de dados: 32
Autores: Morales Vidal, Santo.
La existencia de interacciones intraespecíficas entre aislamientos de una misma especie al infectar un mismo hospedante es muy probable. En esta investigación se estudiaron las interacciones entre aislamientos de Zoophthora radicans, in vitro e in vivo durante la infección de larvas de Plutella xylostella. La identidad de los aislamientos causantes de la infección de larvas de P. xylostella se realizó con base en análisis de PCR-RFLP. Se encontraron diferencias significativas en la virulencia de aislamientos de Z. radicans contra larvas de P. xylostella, los aislamientos obtenidos de larvas infectadas de P. xylostella (NW386 y NW250) fueron más virulentos que aquellos aislamientos obtenidos de otros hospedantes. La temperatura también tuvo un efecto...
Palavras-chave: Infecciones mixtas con Zoophthora radicans; Virulencia; Inoculación dual; Palomilla dorso de diamante; Mixed infections; Virulence; Dual inoculations; Diamondback moth; Entomología y Acarología; Doctorado.
Ano: 2012
URL: http://hdl.handle.net/10521/1725

Diversidad genética en el patosistema maíz-fusarium en el Altiplano de México.
Provedor de dados: 32
Autores: Briones Reyes, Dolores.
Las variantes de maíz (Zea mays L.) nativas (criollos) preservadas por los agricultores a través de generaciones, constituyen más de 80% del área sembrada con maíz en México; la pudrición de mazorca por Fusarium spp. provoca pérdidas de hasta 30%. El estudio de las poblaciones de maíz y sus patógenos como patosistema tiene sentido, pues en la variación genética del maíz nativo se puede encontrar resistencia/tolerancia a enfermedades; el conocimiento de la estructura de las poblaciones de maíz y del patógeno de manera integral ayudaría a resolver el problema de pudrición, aumentar la producción de grano y conservar la diversidad del maíz. En 2010 se colectaron 56 poblaciones de maíz nativo con y sin síntomas de pudrición de mazorca en cinco estados en...
Palavras-chave: Diversidad; Patosistema; Fusarium spp.; Maíz nativo; Pudrición de mazorca; Virulencia; Diversity; Pathosystem; Native maize; Ear rot; Virulence; Genética; Doctorado.
Ano: 2013
URL: http://hdl.handle.net/10521/2163

Nemátodos entomopatógenos en el control de la mosca negra (Dípetera: Sciaridae) en nochebuena (Euphorbia pulcherrima Willd. ex. Klotzch).
Provedor de dados: 32
Autores: Villanueva Sánchez, Evert.
Las “moscas negras” (Diptera: Sciaridae), son plagas primarias en el cultivo de nochebuena en las zonas productoras del centro de México. A pesar de su importancia, no existen antecedentes sobre su identidad taxonómica, su desarrollo y sus alternativas de control diferentes a las químicas. En el presente trabajo se planteó identificar la(s) especie(s) de mosca negra asociada(s) al cultivo, caracterizar los estados biológicos de la especie más abundante, así como evaluar el potencial de control de los nematodos entomopatógenos Heterorhabditis  bacteriophora y Steinernema feltiae a travez del estudio de su persistencia en substrato, su patógenicidad y virulencia. Para identificar las especies, se realizaron recolectas de adultos de la mosca negra en...
Palavras-chave: Bradysia difformis; Heterorhabditis bacteriophora; Steinernema feltiae; Persistencia; Patogenicidad; Virulencia; Persistence; Pathogenicity; Virulence; Entomología y Acarología; Doctorado.
Ano: 2013
URL: http://hdl.handle.net/10521/1899

A fast and simple assay to quantify bacterial leukotoxin activity
Provedor de dados: 69
Autores: Oppermann,Tobias; Schwarz,Stefan; Busse,Nadine; Czermak,Peter.
Background: Mannheimia haemolytica is the primary bacterial pathogen in causing bovine respiratory disease with tremendous annual losses in the cattle industry. The leukotoxin from M. haemolytica is the predominant virulence factor. Several leukotoxin activity assays are available but not standardized regarding sample preparation and cell line. Furthermore, these assays suffer from a high standard error, a prolonged time consumption and often complex sample pretreatments, which is important from the bioprocess engineering point of view. Results: Within this study, an activity assay based on the continuous cell line BL3.1 combined with a commercial available adenosine triphosphate viability assay kit was established. The leukotoxin activity was found to be...
Tipo: Journal article
Palavras-chave: ATP assay; Bacterial pathogen; Bovine respiratory disease; Cattle industry; Critical parameters; Lipopolysaccharides; Mannheimia haemolytica; Microbial biotechnology; Polymyxin B; Quantification; Virulence.
Ano: 2016
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582016000600006

A preliminary survey of M. hyopneumoniae virulence factors based on comparative genomic analysis
Provedor de dados: 74
Autores: Ferreira,Henrique Bunselmeyer; Castro,Luiza Amaral de.
Mycoplasma hyopneumoniae is the etiological agent of porcine enzootic pneumonia (PEP), a major problem for the pig industry. The mechanisms of M. hyopneumoniae pathogenicity allow to predict the existence of several classes of virulence factors, whose study has been essentially restricted to the characterization of adhesion-related and major antigenic proteins. The now available complete sequences of the genomes of two pathogenic and one non-pathogenic strain of M. hyopneumoniae allowed to use a comparative genomics approach to putatively identify virulence genes. In this preliminary survey, we were able to identify 118 CDSs encoding putative virulence factors, based on specific criteria ranging from predicted cell surface location or variation between...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Porcine enzootic pneumoniae; Virulence; Host-pathogen interaction; Antigen; Adhesin.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000200012

Molecular characterization of Indian pathotypes of Puccinia striiformis f. sp. tritici and multigene phylogenetic analysis to establish inter- and intraspecific relationships
Provedor de dados: 74
Autores: Aggarwal,Rashmi; Kulshreshtha,Deepika; Sharma,Sapna; Singh,Vaibhav K.; Manjunatha,Channappa; Bhardwaj,Subhash C.; Saharan,Mahender S.
Abstract Stripe rust caused by Puccinia striiformis f. sp. tritici (Pst) is one of the most devastating diseases of wheat (Triticum spp.) worldwide. Indian isolates were characterised based on their phenotypic reaction on differential hosts carrying different Yr genes. Based on virulence/avirulence structure, isolates were characterised into ten different pathotypes viz. 70S0-2, 67S64, 70S4, 66S0, 70S64, 66S64-1, 38S102, 47S102, 46S119, and 78S84. These Indian pathotypes of P. striiformis f. sp. tritici and 38 pathotypes of other rust species (P. graminis tritici and P. triticina) were used in this study to analyze their molecular phylogenetic relationship. The nucleotides of rDNA-ITS, partial β-tubulin and ketopantoate reductase genes of all the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Wheat; Stripe rust; Virulence; Diversity; Phylogeny.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572018000500834

Doenças da seringueira.
Provedor de dados: 14
Autores: GASPAROTTO, L.; FERREIRA, F. A.
Mal-das-folhas da seringueira: historico de ocorrencias e importancia economica, distribuicao geografica e hospedeiros. Microcyclus ulei: sintomatologia, isolamento, caracteristicas culturais e morfologicas, patogenicidade, variabilidade para virulencia a Hevea spp. e para resistencia ao mal-das-folhas. Ciclo do mal-das-folhas. Epidemiologia do mal-das-folhas. Controle: areas de escape, fungicidas, resistencia da planta, enxertia de copa.
Tipo: Capítulo em livro técnico (INFOTECA-E)
Palavras-chave: Mal-das-folhas; SALB; Morfologia; Ciclo; Virulencia; Brasil; Rubber tree; Fungal diseases; South American leaf blight; Geographic distribution; Host; Symptoms; Isolation methods; Morphology; Cicle; Resistance; Controle Químico; Distribuição Geográfica; Doença; Epidemiologia; Espécie; Folha; Fungo; Hevea; Hospedeiro; Isolamento; Microcyclus Ulei; Patogenicidade; Resistência; Seringueira; Sintoma; Chemical control; Epidemiology; Leaves; Pathogenicity; Virulence.
Ano: 1989
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/667342

Avaliação da virulência de isolados de Corynebacterium pseudotuberculosis em camundongos BALB/c
Provedor de dados: 14
Autores: ROSINHA, G. M. S.; MELO, P. R. de; SANTOS, L. R. dos; CARVALHO, C. E. G.; ALVARENGA, L. C. O.; ANDRADE, G. B.; SOARES, C. O.
Corynebacterium pseudotuberculosis é uma bactéria Gram-positiva, agente etiológico da linfadenite caseosa (LC) em pequenos ruminantes e causadora de piogranulomas, linfangite ulcerativa, mastite e dermatite ulcerativa em bovinos, que são doenças de grande relevância médica e veterinária. Esta doença é de difícil controle e a vacinação é a maneira mais eficiente de preveni-la nos rebanhos. Objetivou-se neste estudo selecionar cepas virulentas de C. pseudotuberculosis, a partir de cinco isolados obtidos de caprinos e ovinos, para uso em estudos de desafio em testes de novas vacinas contra linfadenite caseosa em camundongos. Primeiramente, os isolados foram caracterizados bioquimicamente com o kit API Coryne (APIbioMerieux, Inc., La Balme les Grottes, France)...
Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E)
Palavras-chave: Corynebacterium Pseudotuberculosis; Histopatologia; Linfadenite Caseosa; Patogenicidade; Caseous lymphadenitis; Virulence; Histopathology.
Ano: 2018
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/1106896

Screening of Vibrio isolates to develop an experimental infection model in the Pacific oyster Crassostrea gigas
Provedor de dados: 5
Autores: Gay, Melanie; Berthe, Franck; Leroux, Frederique.
In an attempt to develop a reproducible experimental model of bacterial infection in Crassostrea gigas, oysters taken from very localised sub-populations suffering natural mortality outbreaks were used in cohabitation trials under laboratory conditions. From these trials, a collection of Vibrio strains was isolated from moribund and healthy oysters. In a second step, strains were experimentally tested for virulence by means of injection into healthy oysters. This screening revealed a span of virulence among isolated strains from none to medium. When pooling injected strains, results suggest increased virulence. Vibrio strains may have additive/synergistic action leading to higher C, gigas mortality rates in experimental challenges. Although the study...
Tipo: Text
Palavras-chave: Crassostrea gias; Antagonism; Agonism; Virulence; Vibrio splendidus.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2004/publication-3174.pdf

Molecular epidemiology of Vibrio nigripulchritudo, a pathogen of cultured penaeid shrimp (Litopenaeus stylirostris) in New Caledonia
Provedor de dados: 5
Autores: Goarant, Cyrille; Reynaud, Yann; Ansquer, Dominique; De Decker, Sophie; Saulnier, Denis; Leroux, Frederique.
A collection of 57 isolates of Vibrio nigripulchritudo from either diseased or healthy shrimp and from shrimp farms environment was studied in order to gain a better understanding of the epidemiology of this pathogen, notably isolated from two distinct shrimp disease complexes. Molecular typing using two different techniques, arbitrarily primed PCR (AP-PCR) and multi-locus sequence typing (MLST), studied together with experimental pathology data allowed a relevant epidemiological insight into this possibly emerging pathogen. Additionally, results obtained with the two molecular typing techniques were congruent and allowed discriminating the strains associated with the "Summer Syndrome" from strains isolated from other contexts, especially the other shrimp...
Tipo: Text
Palavras-chave: Virulence; Epidemiology; Typing; MLST; AP PCR; Mariculture; Vibriosis.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-1913.pdf

Mortalités d'huîtres creuses adultes (Crassostrea gigas) et infection à Vibrio aestuarianus - AESTU
Provedor de dados: 5
Autores: Travers, Marie-agnes; Degremont, Lionel; De Lorgeril, Julien; Azema, Patrick; Montagnani, Caroline; Benabdelmouna, Abdellah; Nicolas, Jean-louis; Le Roux, Frederique.
En 2012, le nombre de cas de mortalités d’huîtres creuses adultes rapportés dans le cadre du réseau Repamo, et dans lesquels la bactérie Vibrio aestuarianus a été isolée, a fortement augmenté. Afin d’apporter de premiers éléments de réponse concernant cette augmentation, les objectifs de cette étude étaient de déterminer si l’émergence/la ré-émergence de V. aestuarianus était associée (i) à l’apparition d’un génotype bactérien particulier et/ou (ii) à une sensibilité accrue de certains animaux. L’Ifremer dispose d’une collection de souches bactériennes appartenant majoritairement au genre Vibrio et qui comporte différents isolats de V. aestuarianus, collectés depuis 2001 pendant ou hors épisodes de mortalité. La comparaison de ces isolats en termes de...
Tipo: Text
Palavras-chave: Vibrio aestuarianus; Huître creuse; Crassostrea gigas; Bactérie; Ré-émergenece; Virulence; Génome; Statut immunitaire; Génétique.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00229/34037/32430.pdf

Relation between Biofilm and Virulence in Vibrio tapetis: A Transcriptomic Study
Provedor de dados: 5
Autores: Rodrigues, Sophie; Paillard, Christine; Van Dillen, Sabine; Tahrioui, Ali; Berjeaud, Jean-marc; Dufour, Alain; Bazire, Alexis.
Marine pathogenic bacteria are able to form biofilms on many surfaces, such as mollusc shells, and they can wait for the appropriate opportunity to induce their virulence. Vibrio tapetis can develop such biofilms on the inner surface of shells of the Ruditapes philippinarum clam, leading to the formation of a brown conchiolin deposit in the form of a ring, hence the name of the disease: Brown Ring Disease. The virulence of V. tapetis is presumed to be related to its capacity to form biofilms, but the link has never been clearly established at the physiological or genetic level. In the present study, we used RNA-seq analysis to identify biofilm- and virulence-related genes displaying altered expression in biofilms compared to the planktonic condition. A...
Tipo: Text
Palavras-chave: Biofilm; Virulence; Vibrio tapetis; Transcriptome; Quorum sensing; Type VI secretion system; Brown ring disease.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00470/58140/60611.pdf

Identification de marqueurs génétiques de la virulence chez Vibrio nigripulchritudo, un pathogène de crevettes pénéides en Nouvelle-Calédonie
Provedor de dados: 5
Autores: Reynaud, Yann.
Since 1997, a new pathology seasonally occurs in new caledonian shrimp farms during the warm season and was named Summer Syndrome. Diseased Litopenaeus stylirostris shrimp suffer from a septicemic vibriosis which was attributed to V. nigripulchritudo. Preliminary studies based on a collection of V. nigripulchritudo strains have brought to light different virulence levels according to experimental infections results; three virulence statuses were defined: highly (HP), moderately (MP) and non pathogenic (NP). The aim of this work was to genetically characterize virulent V. nigripulchritudo strains. In a first step the genetic diversity of 58 V. nigripulchritudo strains was analyzed by MLST and AP-PCR, revealing a cluster of HP and MP strains, characterized...
Tipo: Text
Palavras-chave: Plasmide; SSH; Épidémiology; Virulence; Shrimp; Vibriosis; Vibrio nigripulchritudo; Plasmide; SSH; Épidémiologie; Virulence; Crevette; Vibriose; Vibrio nigripulchritudo.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/these-3906.pdf

Comparative analysis of Vibrio splendidus-related strains isolated during Crassostrea gigas mortality events
Provedor de dados: 5
Autores: Le Roux, Frédérique; Gay, Melanie; Lambert, Christian; Waechter, Magali; Poubalanne, Saravanne; Chollet, Bruno; Nicolas, Jean-louis; Berthe, Franck.
French mollusc production is based mainly on the Pacific cupped oyster, Crassostrea gigas. Since 1991, annual mass mortality of juveniles has been reported during summer months. These recurring episodes concern professionals who fear that like Portugese oyster, C. angulata, C gigas could in turn disappear following one of these epizooties. Previously, bacteriological analysis of moribund oyster juveniles yielded an isolate of a Vibrio splendidus biovar H strain, named TNEMF6. This isolate was demonstrated to be pathogenic to Crassostrea gigas spat by experimental challenge. To study the association between summer oyster mortality and presence of TNEMF6 cluster strains, Vibrionaceae fauna were isolated from infected spat along the French Atlantic coast...
Tipo: Text
Palavras-chave: Vibrio splendidus; Virulence; Epidemiology; PCR RFLP; Oyster mortality.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/2002/publication-565.pdf

Etude de la virulence des Vibrio pathogènes en relation avec la variabilité de la réponse chez l'uître creuse
Provedor de dados: 5
Autores: De Decker, Sophie.
The bacteria of the Vibrio genus are one of the most abundant groups in the aquatic ecosystems. Two species of vibrios, Vibrio splendidus and V. Aestuarianus, have been associated, in some cases, to mortality in flat oyster Crassostrea gigas farms, most of the time during the summer period. This doctoral thesis studies the Vibrio-host interaction and their modulations according to the host's pathogenic virulence and its genetic, physiologic and immunitary parameters. These factors will be characterised by in vitro and in vivo approaches (experimental infection). The characterization of contrasted genetic families according to their sensitivity to these vibrios will enable the implementation of new improvement strategies in oyster farms (prophylactic...
Tipo: Text
Palavras-chave: Immunologie; Physiologie; Paramètres génétiques; Virulence; Oyster; Crassostrea gigas; Pathogène; Vibrio.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/acte-3431.pdf

Comparative genomics of pathogenic lineages of Vibrio nigripulchritudo identifies virulence-associated traits
Provedor de dados: 5
Autores: Goudenege, David; Labreuche, Yannick; Krin, Evelyne; Ansquer, Dominique; Mangenot, Sophie; Calteau, Alexandra; Medigue, Claudine; Mazel, Didier; Polz, Martin F.; Le Roux, Frederique.
Vibrio nigripulchritudo is an emerging pathogen of farmed shrimp in New Caledonia and other regions in the Indo-Pacific. The molecular determinants of V. nigripulchritudo pathogenicity are unknown; however, molecular epidemiological studies have suggested that pathogenicity is linked to particular lineages. Here, we performed high-throughput sequencing-based comparative genome analysis of 16 V. nigripulchritudo strains to explore the genomic diversity and evolutionary history of pathogen-containing lineages and to identify pathogen-specific genetic elements. Our phylogenetic analysis revealed three pathogen-containing V. nigripulchritudo clades, including two clades previously identified from New Caledonia and one novel clade comprising putatively...
Tipo: Text
Palavras-chave: Horizontal gene transfer; Nigritoxin; Phylogeny; Shrimp; Virulence; Vibrio.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00160/27117/28369.pdf

Survie et maintien de la virulence de Salmonella Typhimurium VNC exposée simultanément à trois facteurs stressants expérimentaux
Provedor de dados: 5
Autores: Baleux, B; Caro, A; Lesne, J; Got, P; Binard, S; Delpeuch, B.
The release of enteric pathogenic bacteria in aquatic environments poses the problem of the fate of these bacteria under the effects of environmental factors (solar radiation, salt concentration, temperature, nutrient level, pH, competition). Frequently, these bacterial cells, potentially pathogenic, enter into a non-culturable state on routine bacteriological plating media. However, the use of direct detection methods (DAPI stained cells) allows the visualization of these Viable but Non Culturable cells (VNC). But, beyond the characterization of the viability of the cells (electron transport activity, metabolic activity, membrane integrity, structure and/or quantity of DNA), what happens with the virulence of these cells? This problem was experimentally...
Tipo: Text
Palavras-chave: Salmonella; Survie; Virulence; VNC; Stress; Salmonella; Survival; Virulence; VNC; Stress.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00325/43645/43245.pdf

Diagnosis of vibriosis in the era of genomics: lessons from invertebrates
Provedor de dados: 5
Autores: Le Roux, Frederique.
Global changes linked to increases in temperature and ocean acidification, but also to more direct anthropogenic influences such as aquaculture, have caused a worldwide increase in the reports of Vibrio-associated illnesses affecting humans and also animals such as shrimp and molluscs. Investigation of the emergence of Vibrio pathogenesis events requires the analysis of microbial evolution at the gene, genome and population levels, in order to identify genomic modifications linked to increased virulence, resistance and/or prevalence, or to recent host shift. From a more applied point of view, the elucidation of virulence mechanisms is a prerequisite to devising prophylactic methods to fight infectious agents. In comparison with human pathogens, fairly...
Tipo: Text
Palavras-chave: Écologie; Émergence; Évolution; Invertébrés marins; Vibriose; Virulence; Ecology; Emergence; Evolution; Marine invertebrate; Vibriosis; Virulence.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00344/45560/46722.pdf

Interaction de la bactérie Vibrio harveyi avec son hôte, l'hormeau Haliotis tuberculata : approches physiologiques, cellulaires et moléculaires
Provedor de dados: 5
Autores: Travers, Marie-agnes.
Abalone aquaculture only recently developed in western Europe, but already it has to face numerous pathologies. Since 1998, the natural and farm stocks of Haliotis tuberculata suffer regularly high mortalities, mainly due to the pathogenic bacterium, Vibrio harveyi. The vibriosis of the European abalone, in particular its macroscopic signs, and the conditions necessary for its development have been studied in detail by field and laboratory experiments. We have been able to show the importance of the interplay between water temperature (&gt;17°C), animal physiology (reproduction period) and a pathogenic strain (harbouring the plasmid pVCR1) for the development of this abalone disease. A limited localisation study of the abalone target tissues (gills, muscle...
Tipo: Text
Palavras-chave: Ormeau; Haliotis tuberculata; Bactéries; Vibrio harveyi; Vibriose; Température; Immunité; Reproduction; Hémocytes; MAP Kinases; Plasmide; Virulence; GFP; Abalone; Haliotis tuberculata; Bacteria; Vibrio harveyi; Vibriosis; Temperature; Immunity; Reproduction; Haemocytes; MAP Kinases; Plasmid; Virulence; GFP.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/00176/28729/27196.pdf

Les Escherichia Coli potentiellement pathogenes dans l’environnement littoral : cas des STEC et des EPEC
Provedor de dados: 5
Autores: Baliere, Charlotte.
The contamination of coastal areas by potentially pathogenic enteric bacteria is of concern for the sustainability of some uses, such as shellfish farming, recreational shellfish harvesting and bathing. The contamination of these environments may occur through the land-spreading of livestock wastes, animal feces deposited on pastures, wastewaters from slaughterhouses or from municipal wastewater treatment plants. The presence of these bacteria in coastal environment may present a potential risk to human health. In fact, shellfish-borne outbreaks or human infections may occur by the consumption of shellfish from contaminated areas or the ingestion of water during bathing in contaminated waters, respectively. To date, few studies focusing on the presence and...
Tipo: Text
Palavras-chave: STEC; EPEC; Coquillages; Diversité; Virulence; Persistance; STEC; EPEC; Shellfish; Diversity; Virulence; Persistence.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00312/42322/41653.pdf

Differential Mortality and High Viral Load in Naive Pacific Oyster Families Exposed to OsHV-1 Suggests Tolerance Rather than Resistance to Infection
Provedor de dados: 5
Autores: Agnew, M. Victoria; Friedman, Carolyn S.; Langdon, Christopher; Divilov, Konstantin; Schoolfield, Blaine; Morga, Benjamin; Degremont, Lionel; Dhar, Arun K.; Kirkland, Peter; Dumbauld, Brett; Burge, Colleen A.
Pacific oysters, Crassostrea gigas, are one of the most productive aquaculture species in the world. However, they are threatened by the spread of Ostreid herpesvirus-1 (OsHV-1) and its microvariants (collectively “µvars”), which cause mass mortalities in all life stages of Pacific oysters globally. Breeding programs have been successful in reducing mortality due to OsHV-1 variants following viral outbreaks; however, an OsHV-1-resistant oyster line does not yet exist in the United States (US), and it is unknown how OsHV-1 µvars will affect US oyster populations compared to the current variant, which is similar to the OsHV-1 reference, found in Tomales Bay, CA. The goals of this study were to investigate the resistance of C. gigas juveniles produced by the...
Tipo: Text
Palavras-chave: OsHV-1; Mu vars; Oyster; Virus; Tolerance; Virulence; QPCR.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00665/77739/79862.pdf

Vibrio nigripulchritudo monitoring and strain dynamics in shrimp pond sediments
Provedor de dados: 5
Autores: Walling, Emilie; Vourey, Elodie; Ansquer, Dominique; Beliaeff, Benoit; Goarant, C.
Aims: A description of bacterial pathogens in shrimp ponds is necessary to understand their pathogenesis. Vibrio nigripulchritudo was shown to contain saprophytic and pathogenic strains among New Caledonian isolates. We established a method to map the development of V. nigripulchritudo in pond sediments at three different genetic levels: the species level, then at the pathogenic cluster level and finally at the plasmid level, present only in all highly pathogenic isolates. Methods and Results: PCR methods were applied to shrimp pond sediments both before and after a mortality outbreak. Using crude samples, the species V. nigripulchritudo is not detected at first (0/42 samples at day 56 post stocking) but appears frequently in the sediments after the...
Tipo: Text
Palavras-chave: Detection; Diagnosis; Diseases; Ecology; PCR; Plasmids; Soil; Virulence.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00004/11484/8177.pdf

Non-native aquatic animals introductions have driven disease emergence in Europe
Provedor de dados: 5
Autores: Peeler, Edmund J.; Oidtmann, Birgit C.; Midtlyng, Paul J.; Miossec, Laurence; Gozlan, Rodolphe E.
In this paper it is argued, using examples of disease emergence in aquatic animals in Europe, that the introduction of non-native species drives disease emergence by both extending the geographic range of parasites and pathogens and facilitating host-switching. Enteric red mouth disease and infectious haematopoietic necrosis of salmonids have extended their geographic range from North America to Europe with the import of live fish (Pimephales promelas) and rainbow trout eggs, respectively. Host-switching results in disease emergence when previously unidentified commensal organisms or known pathogen switch to new naïve hosts. The most serious endemic diseases of wild aquatic animals in Europe in recent years can be traced to the introduction of non-native...
Tipo: Text
Palavras-chave: Aquaculture; Transmission; Control; Pathways; Virulence; Fish.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00033/14431/14066.pdf

Temperature modulate disease susceptibility of the Pacific oyster Crassostrea gigas and virulence of the Ostreid herpesvirus type 1
Provedor de dados: 5
Autores: Delisle, Lizenn; Petton, Bruno; Burguin, Jean Francois; Morga, Benjamin; Corporeau, Charlotte; Pernet, Fabrice.
Temperature triggers marine diseases by changing host susceptibility and pathogen virulence. Oyster mortalities associated with the Ostreid herpesvirus type 1 (OsHV-1) have occurred seasonally in Europe when the seawater temperature range reaches 16–24 °C. Here we assess how temperature modulates oyster susceptibility to OsHV-1 and pathogen virulence. Oysters were injected with OsHV-1 suspension incubated at 21 °C, 26 °C and 29 °C and were placed in cohabitation with healthy oysters (recipients) at these three temperatures according to a fractional factorial design. Survival was followed for 14 d and recipients were sampled for OsHV-1 DNA quantification and viral gene expression. The oysters were all subsequently placed at 21 °C to evaluate the potential...
Tipo: Text
Palavras-chave: Bivalve; Health; Marine disease; Mortality risk; Temperature; Virulence.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00442/55337/56847.pdf

Molecular Targets for Coevolutionary Interactions Between Pacific Oyster Larvae and Their Sympatric Vibrios
Provedor de dados: 5
Autores: Wegner, K. Mathias; Piel, Damien; Bruto, Maxime; John, Uwe; Mao, Zhijuan; Alunno-bruscia, Marianne; Petton, Bruno; Le Roux, Frederique.
Bacteria of the Vibrio genus are the most predominant infectious agents threatening marine wildlife and aquaculture. Due to the large genetic diversity of these pathogens, the molecular determinants of Vibrio virulence are only poorly understood. Furthermore, studies tend to ignore co-evolutionary interactions between different host populations and their locally encountered Vibrio communities. Here, we explore the molecular targets of such co-evolutionary interactions by analyzing the genomes of nine Vibrio strains from the Splendidus-clade showing opposite virulence patterns towards two populations of Pacific oysters introduced into European Wadden Sea. By contrasting Vibrio phylogeny to their host specific virulence patterns, we could identify two core...
Tipo: Text
Palavras-chave: Virulence; Host-pathogen interaction; Local adaptation; Biological invasion; Emerging disease; Wadden Sea.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00512/62409/66669.pdf

Bioprotective Effect of Lactococcus piscium CNCM I-4031 Against Listeria monocytogenes Growth and Virulence
Provedor de dados: 5
Autores: Saraoui, Taous; Leroi, Francoise; Chevalier, Frederique; Cappelier, Jean-michel; Passerini, Delphine; Pilet, Marie-france.
Listeria monocytogenes is a Gram-positive pathogen occurring in many refrigerated ready-to-eat foods. It is responsible for foodborne listeriosis, a rare but severe disease with a high mortality rate (20–30%). Lactococcus piscium CNCM I-4031 has the capacity to prevent the growth of L. monocytogenes in contaminated peeled and cooked shrimp and in a chemically defined medium using a cell-to-cell contact-dependent mechanism. To characterize this inhibition further, the effect of L. piscium was tested on a collection of 42 L. monocytogenes strains. All strains were inhibited but had different sensitivities. The effect of the initial concentration of the protective and the target bacteria revealed that the inhibition always occurred when L. piscium had reached...
Tipo: Text
Palavras-chave: Biopreservation; Lactococcus piscium; Listeria monocytogenes; Co-culture; Cell ratio; Scanning electron microscopy; Virulence.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00449/56065/57588.pdf

The versatile strategies of Escherichia coli pathotypes: a mini review
Provedor de dados: 80
Autores: Sousa,C. P.
The widespread species Escherichia coli includes a broad variety of different types, ranging from highly pathogenic strains to avirulent isolates. Few microorganisms are as versatile as E. coli. Pathogenic strains remain a leading cause of severe and persistent infant diarrhea in developing countries. They may be limited to colonization of a mucosal surface or can disseminate throughout the body and have been implicated in urinary tract infection, sepsis/meningitis and gastrointestinal infection. The human gastrointestinal tract is susceptible to diarrheagenic E. coli infections. Escherichia coli have effectively managed to subvert the host cytoskeleton for their own purposes causing substantial diarrheal disease, a major public health problem worldwide....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Pathogenicity; Virulence; Escherichia coli pathotypes; Versatile strategies; Diarrheagenic E. coli categories; Public health.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-91992006000300002

Occurrence of apocrine secretion in the larval gut epithelial cells of Aedes aegypti L., Anopheles albitarsis Lynch-Arribálzaga and Culex quinquefasciatus say (Diptera: Culicidae): a defense strategy against infection by Bacillus sphaericus Neide?
Provedor de dados: 82
Autores: Oliveira,Caroline D; Tadei,Wanderli P; Abdalla,Fábio C.
Cell hypertrophy was the first reaction of the gut epithelial cells of Aedes aegypti (L.), Anopheles albitarsis (Lynch-Arribálzaga) and Culex quinquefasciatus (Say) to the toxins of strains 2362 and S1116 of Bacillus sphaericus, as cells had an increase of intracellular secretory activity. Soon after the cell hypertrophy developed, vesicles were formed at the cell apical portion, which detached with the plasma membrane, characterizing a type of apocrine secretion like. The first pathway of contamination of the mosquito larvae by these bacteria is through the gut, by feeding. Depending on the species of Culicidae and on the bacterial strain used, the hypertrophy of the gut epithelium occurred between 5 and 15 min after exposure to the contaminated...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mosquito; Biological control; Virulence.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-566X2009000500010

Virulence characterization of Campylobacter jejuni isolated from resident wild birds in Tokachi area, Japan
Provedor de dados: 19
Autores: SHYAKA, Anselme; KUSUMOTO, Akiko; CHAISOWWONG, Warangkhana; OKOUCHI, Yoshiki; FUKUMOTO, Shinya; YOSHIMURA, Aya; KAWAMOTO, Keiko; 楠本, 晃子; 福本, 晋也; 川本, 恵子.
The prevalence of Campylobacter jejuni in wild birds is a potential hazard for human and animal health. The aim of this study was to establish the prevalence of C. jejuni in wild birds in Tokachi area, Hokkaido, Japan and investigate their virulence in vitro. In total, 173 cloacal swabs from individual wild birds were collected for the detection of Campylobacter spp. Thirty four samples (19.7%) were positive for Campylobacter of which 94.1% (32/34 samples) were C. jejuni. Additionally, one C. coli and one C. fetus were isolated. Seven C. jejuni isolates (one from crows and the other from pigeons) had important virulence genes including all three CDT genes (cdtA, cdtB and cdtC) and flaA, flaB, ciaB and cadF, and the other isolates were lacking cdtA gene....
Palavras-chave: Campylobacter; Japan; Virulence; Wild bird.
Ano: 2015
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4177

An Overview on Marek’s Disease Virus Evolution and Evidence for Increased Virulence in Brazil
Provedor de dados: 89
Autores: Torres,ACD; Marin,SY; Costa,CS; Martins,NRS.
ABSTRACT Marek’s disease virus (MDV) has been shown to be evolving to higher virulence. One of the genetic sites involved in virulence which enables such characterization is the 339-amino acid Meq protein encoding gene (meq). The reemergence of clinical Marek’s disease (MD) in vaccinated flocks can be associated to changes in meq. Our studies have shown the presence of very virulent MDV strains in the Brazilian industrial and free-range poultry. We present an overview of MD increasing severity and indicate the necessity of using phylogenetic tools for best accompanying MDV evolution.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Gallid herpesvirus 2; Marek’s disease virus; Gallus gallus domesticus; Meq gene; Virulence.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2019000100325

Molecular characterization of Listeria monocytogenes isolated from foods
Provedor de dados: 59
Autores: Pimenta,Fabiana Cristina; Furlanetto,Sirdéia Maura Perrone; Mayer,Leonard W.; Timenetsky,Jorge; Santos,Manoel Armando Azevedo dos.
A total of 30 strains of Listeria monocytogenes isolated from different foods (16 of differents kinds of sausage, 14 cheese,) purchased at groceries of São Paulo City were ribotyped and analysed for the presence and expression of hemolysin gene and production of phosphatidylinositol-specific phosphalipase C - PI-PLC enzyme. The L. monocytogenes strains were differentiated into six ribotype classes. A total of 13 (43.3%) from these strains belong to the same ribotype (ribotype I), and was coincident to the ribotype of the standard L. monocytogenes prototype strain (ATCC-15313). The hemolytic activity was observed in 29 (96.7%) strains when incubated at 37oC, but not at 4oC. The direct colony hybridization method for hemolysin gene detection showed a...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Listeria monocytogenes; Ribotyping; Virulence; Factors; Food.
Ano: 1999
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37141999000400011

ความหลากหลายของแหล่งที่มาของเพลี้ยกระโดดสีน้ำตาลต่อความรุนแรงในการทำลายข้าวพันธุ์ต่างๆ
Provedor de dados: 106
Autores: Orrachoan Poolsiri; Noppadol Kiripetch.
The brown planthopper (BPH) is one of the most important insect pests imposing limitations on the production of rice. The objective of this study is to investigate the effects of 32 BPH populations on 21 varieties of rice with differences in resistance to BPH while the TN1 variety used for a susceptible check. The previou by seedling box screening techniques and Standard Evaluation System for Rice. However, the limitation of this study was the analysis of data using only cluster analysis to group the sources of BPH and rice varieties but there was no detailed analysis for each group.
Tipo: PhysicalObject
Palavras-chave: Virulence; Resistanct; BPH; Biotype; ข้าว; พันธุ์ต้านทาน; เพลี้ยกระโดดสีน้ำตาล; ความหลากหลายทางชีวชนิด; ความรุนแรง.
Ano: 2012
URL: http://anchan.lib.ku.ac.th/agnet/handle/001/5443

ความแตกต่างในความรุนแรงของเพลี้ยกระโดดสีน้ำตาลต่อการเข้าทำลายพันธุ์ข้าว
Provedor de dados: 106
Autores: Jate Kotcharerk; Phamorn Pattawatang.
Evaluation of the ability of rice varieties in resistance to brown plant hopper was performed using seed box screen test. The brown plant hopers (BPH) were collected from rice paddy fields in Phitsanulok, Chainat, and Ang Thong Province. From cluster analysis at level 0.8, there were three different groups classified by the different level of rice plant damage after treated by the insects. The three different level of damage were graded by the ability in resistance to the BPH as resistance, moderately resistance and susceptible. Considering in biotype of the BPH, the results indicated that there were variety of BPH biotypes in each samples collected from the three different provinces. Mainly, the biotype 4 and 5 were indentified in these samples. However,...
Tipo: PhysicalObject
Palavras-chave: Brown plant hopper; Biotype; Virulence; Paddy field; Rice variety; Resistance varieties; Nilaparvata lugens; Outbreak; Pest resistance; เพลี้ยกระโดดสีน้ำตาล; ชีวชนิด; ปฏิกิริยาความรุนแรง; จังหวัดพิษณุโลก; พันธุ์ต้านทาน; พันธุ์ข้าว; นาข้าว; ยีนต้านทานแมลงศัตรูพืช; การถ่ายทอดทางพันธุกรรม; การระบาดของแมลงศัตรูพืช; ปฏิกิริยาความรุนแรง.
Ano: 2014
URL: http://anchan.lib.ku.ac.th/agnet/handle/001/5681

Pathogenicity, molecular characterization, and cercosporin content of Brazilian isolates of Cercospora kikuchii
Provedor de dados: 102
Autores: Almeida,Álvaro M. R.; Piuga,Fernanda F.; Marin,Silvana R. R.; Binneck,Eliseu; Sartori,Fábio; Costamilan,Leila M.; Teixeira,Maria R. O.; Lopes,Marcelo.
Cercospora kikuchii, involved with the defoliation of soybean (Glycine max) plants, is normally associated with Septoria glycines in late season. Seventy-two isolates from different regions in Brazil, obtained mainly from purple stained seeds, showed phenotypic variation. Cercosporin content and rate of colony growth was higly variable among isolates. A strong correlation between cercosporin content and virulence was identified. Genetic variation among and within populations was evaluated based on 86 RAPD loci. The RAPD analysis clustered all isolates into seven groups. No relationship was observed between RAPD groups and geographic origin or cercosporin content. The sequence of the internal spacer regions (ITS1-5.8S-ITS2) from 13 isolates chosen according...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Genotypic diversity; PCR-RFLP; RAPD; ITS sequence; Virulence.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-41582005000600005

Estimation of phenotypic diversity in field populations of Magnaporthe grisea from two upland rice cultivars
Provedor de dados: 102
Autores: Silva,Gisele B.; Zambolim,Laércio; Prabhu,Anne S.; Araújo,Leila G.; Zimmermann,Francisco J.P.
The phenotypic diversity of Magnaporthe grisea was evaluated based on leaf samples with blast lesions collected from eight commercial fields of the upland rice cultivars 'BRS Primavera' and 'BRS Bonança', during the growing seasons of 2001/2002 and 2002/2003, in Goias State. The number of M. grisea isolates from each field utilized for virulence testing varied from 28 to 47. Three different indices were used based on reaction type in the eight standard international differentials and eight Brazilian differentials. The M. grisea subpopulations of ´Primavera' and 'Bonança', as measured by Simpson, Shannon and Gleason indices, showed similar phenotypic diversities. The Simpson index was more sensitive relation than those of Shannon and Gleason for pathotype...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Oryza sativa; Pyricularia grisea; Population dynamics; Rice blast; Pathotypes; Virulence.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-41582007000100001

Pathotype diversity of Pyricularia grisea from improved upland rice cultivars in experimental plots
Provedor de dados: 102
Autores: PRABHU,ANNE S.; FILIPPI,MARTA C.; ARAUJO,LEILA G.
A study was undertaken to examine the pathogenic diversity of Pyricularia grisea isolates retrieved from 14 upland rice (Oryza sativa) cultivars in experimental plots during a period of five years. Inoculations were performed on 32 genotypes with 85 monoconidial isolates under controlled greenhouse conditions. Based on the reaction pattern of eight international differentials, eleven pathotypes of P. grisea were identified. The predominant international races or pathotypes were IB-9 (56.4%), IB-1 (16.4%) and IB-41 (11.8%). A set of eight commercial upland rice cultivars ('Carajás', 'Confiança', 'Maravilha', 'Primavera', 'Progresso', 'Caiapó', 'IAC-47', 'IAC-201') was utilized as additional differentials for describing the virulence pattern of P. grisea....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Oryza sativa; Magnaporthe grisea; Physiologic races; Differential varieties; Resistance; Virulence.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-41582002000500005

Variability of the anthracnose fungus Colletotrichum graminicola in sorghum genotype mixtures
Provedor de dados: 102
Autores: Valério,Henrique M.; Casela,Carlos R.; Resende,Maria A.; Santos,Fredolino G.
This paper reports partial results obtained on the variability of Colletotrichum graminicola developed in response to the host diversity generated by three-line combination of sorghum (Sorghum bicolor) genotypes. Nine sorghum lines were used in this study: CMSXS210B, CMSXS112B, CMSXS215B, CMSXS221B, CMSXS169R, CMSXS180R, CMSXS182R, CMSXS227R, and CMSXS116R. A total of 39 treatments on mixtures and pure stands of the component lines were evaluated in the field for the development of anthracnose, as a natural epidemic. Samples of the single spore isolates of the pathogen of each treatment indicated a reduction in the phenotypic diversity and an increase in the frequency of more complex races in genotype mixtures in relation to the pure stands of each genotype.
Tipo: Info:eu-repo/semantics/report
Palavras-chave: Sorghum bicolor; Diseases; Virulence; Diversity.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-41582004000500019

Variability in isolates of Puccinia polysora in Brazil
Provedor de dados: 102
Autores: CASELA,CARLOS R.; FERREIRA,ALEXANDRE S.
The main objective of this work was to evaluate the variability of the southern rust pathogen Puccinia polysora in Brazil, based on its virulence on a set of maize (Zea mays) cultivars. Sixty single pustule isolates, from different areas of occurrence of southern rust, were evaluated for their virulence to 50 maize experimental hybrids. Six cultivars showed a clear distinction between susceptible and resistant reaction, and were used to characterize the variability of the pathogen. Seventeen virulence patterns were identified among the 60 isolates tested. The most frequent virulence patterns identified, were observed in all locations of sampling, which suggests the absence of geographical differentiation among prevalent populations of P. polysora in Brazil.
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Southern rust; Virulence.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-41582002000400015

Differences in competitive ability among races of Colletotrichum graminicola in mixtures
Provedor de dados: 102
Autores: CASELA,CARLOS R.; FERREIRA,ALEXANDRE S.; SANTOS,FREDOLINO G.
Mixtures of races of Colletotrichum graminicola, causing sorghum (Sorghum bicolor) anthracnose and differing in their virulence range, were inoculated for five and six generations on the susceptible sorghum cultivar BR009 (Tx623), in two experiments in a greenhouse. In each generation a sample of 50 single spore isolates was obtained and inoculated on a standard differential set to determine the proportion of each race in the mixture. Isolates of the race 30A, with the narrowest virulence range, predominated over isolates of the more complex races 31B, 31C and 31E indicating the existence of differences in the survival ability among races of this pathogen.
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Colletotrichum graminicola; Virulence; Fitness; Sorghum bicolor; Anthracnose.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-41582001000200019

Effect of continuous growing of resistant soybean genotypes on Meloidogyne arenaria race 1 reproduction
Provedor de dados: 102
Autores: PEDROSA,ELVIRA M.R.; MOURA,ROMERO M.
Even though resistance is the most promising tactic for root-knot nematode management on soybean (Glycine max), virulent biotypes may occur and be selected on specific resistant plant genotypes. In the present study, reproduction rate of Meloidogyne arenaria race 1 increased after four sequences of continuous culture of the parasite on resistant soybean genotypes.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Glycine max; Resistance; Root-knot nematode; Virulence.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-41582001000100017

Pathogenic, morphological and genetic diversity in Plasmopara halstedii, the causal agent of sunflower downy mildew - doi: 10.4025/actasciagron.v35i1.15722
Provedor de dados: 1
Autores: Sakr, Nachaat; Syrian Atomic Energy Commission.
Pathogenic, morphological and genetic variation was studied in 35 Plasmopara halstedii (sunflower downy mildew) isolates of different races. Virulence spectrum was analyzed in sunflower hybrids carrying effective Plgenes. Aggressiveness was analyzed in one sunflower inbred line showing a high level of quantitative resistance. There were differences in virulence spectrum for pathogen isolates. Index of aggressiveness was calculated for each isolate and two groups were revealed as more aggressive isolates of 100 and 3xx races, and less aggressive isolates of 7xx races. Significant morphological differences were found in zoosporangia and sporangiophores morphology. Genetic relationships were detected between the pathogen isolates using 12 EST-derived markers....
Palavras-chave: Aggressiveness; EST-derived markers; Virulence; Zoosporangia; Sporangiophores aggressiveness; EST-derived markers; Virulence; Zoosporangia; Sporangiophores.
Ano: 2012
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/15722

Experimental infection with different bacterial strains in larvae and juvenile Litopenaeus vannamei reared in Santa Catarina State, Brazil - doi: 10.4025/actascibiolsci.v32i3.5471
Provedor de dados: 3
Autores: Buglione, Celso Carlos; UFSC; Vieira, Felipe do Nascimento; UFSC; Mouriño, José Luiz Pedreira; UFSC; Pedrotti, Fabiola Santiago; UFSC; Jatoba, Adolfo; UFSC; Martins, Maurício Laterça; UFSC.
This study evaluated the pathogenic characteristics of bacteria isolated from Litopenaeus vannamei during an outbreak at the Laboratory of Marine Shrimp, UFSC, Santa Catarina State, Brazil. Their  virulence potential in larvae and juvenile shrimp and the effects on the total haemocyte count, phenoloxidase activity and serum agglutinate titre were examined after experimental infection. Bacterial strains were isolated from larvae and adult shrimps, identified by the AP120E biochemical system as: two strains of Vibrio alginolyticus, three of Aeromonas salmonicida and one of Pasteurella multocida sp. and Pasteurella sp. All the bacterial strains isolated in this study caused mortality in shrimp. One strain of V. alginolyticus was responsible for 97.3 and 88.7%...
Tipo: Resistencia a infecção
Palavras-chave: 2.12.01.02-1 Shrimp; Experimental infection; Vibrio; Virulence; Immunology bacteriologia Shrimp; Experimental infection; Vibrio; Virulence; Immunology.
Ano: 2010
URL: http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/5471

Antimicrobial resistance, diarrheagenic and avian pathogenic virulence genes in Escherichia coli from poultry feed and the ingredients
Provedor de dados: 45
Autores: Rossato,J.M.; Brito,B.G.; Kobayashi,R.K.T.; Koga,V.L.; Sarmiento,J.J.P.; Nakazato,G.; Lopes,L.F.D.; Balsan,L.A.G.; Grassotti,T.T.; Brito,K.C.T.
ABSTRACT Diarrheagenic (DEC) and avian pathogenic Escherichia coli (APEC) are associated with intestinal and extra-intestinal infections (ExPEC), respectively. We aimed to analyze the antimicrobial susceptibility, gene encoding virulence factors associated to DEC and APEC, and phylogenetic classification in E. coli isolated from 320 samples of feed and ingredients. Antimicrobial susceptibility was performed using the disk diffusion method and Multiple Antibiotic Resistance (MAR) Index and Multi-Drug Resistance (MDR) were calculated. Phylogenetic classification was performed on samples harboring DEC and/or APEC virulence-associated genes. A total of 110 E. coli strains were isolated in 15% (49/320) of the evaluated inputs (n=13 vegetable meal; n=33 animal...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Poultry production; Animal feed; Antimicrobials; Virulence; Resistance.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352019000601968

Partial characterization of a Brazilian strain of Aujeszky’s disease virus recovered from a pig with subclinical infection
Provedor de dados: 45
Autores: Cândido,A.L.; Resende,M.; Oliveira,M.E.; Bontempo,E.D.; Drumond,B. P.
One Brazilian strain of Aujeszky’s disease virus isolated from a piglet in which the disease had not been observed was studied as for its virulence in pigs. The genome of the virus was molecularly analysed as for their restriction endonuclease cleavage pattern. Fifty-day-old non-immune weanlings exposed to this strain showed no disease although the virus was present in their oropharyngeal area for at least three days. All animals developed moderate titers of neutralizing antibody. Based on number of bands and migration rate of restriction fragments the isolate was classified into Herrmann’s type I group. Latent infection was detected in all pigs by PCR. Some variations were detected in the cleavage pattern of the strain ASB Piau when compared to LA031...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Swine; Aujeszky’s disease virus; Virulence; Latency.
Ano: 2000
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352000000400001

Virulence, resistance, and genetic relatedness of Escherichia coli and Klebsiella sp. isolated from mule foals
Provedor de dados: 45
Autores: Carneiro,V.C.; Lessa,D.A.B.; Guttmann,P.M.; Magalhaes,H.; Aquino,M.H.C.; Cunha,L.E.R.; Arais,L.R.; Cerqueira,A.M.F.
ABSTRACT Respiratory diseases are common in young horses but little is known about such infections in mule foals. This study aimed to characterize Escherichia coli and Klebsiella sp. isolated from tracheal wash (TW) and fecal samples (FS) of mule foals, with or without cytological evidence of respiratory disease. Strains were analyzed against 13 antimicrobials, for presence of Extended spectrum beta-lactamase (ESBL), and virulence genes. Phylogrouping and Randomic (RAPD)-PCR profiles were used to evaluate their genetic relatedness. E. coli strains from TW and FS showed greatest resistance to tetracycline, while Klebsiella strains were mainly resistant to ampicillin; multidrug resistance and ESBL production were also detected. The blaCTX gene prevailed...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Escherichia coli; Klebsiella; Respiratory disease; Virulence; Antimicrobial resistance.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352017000501073

Establishment of a pathogenicity index in Salmonella Enteritidis and Salmonella Typhimurium strains inoculated in one-day-old broiler chicks
Provedor de dados: 45
Autores: Lima,D.A.; Furian,T.Q.; Pillati,R.M.; Silva,G.L.; Morgam,R.B.; Borges,K.A.; Fortes,F.B.B.; Moraes,H.L.S.; Brito,B.G.; Brito,K.C.T.; Salle,C.T.P.
Salmonella Enteritidis and Salmonella Typhimurium are responsible for causing huge economic loses in aviculture, as they lead young broiler chicks to develop clinical disease and thus increase mortality. Salmonella's pathogenicity is considered complex and multifactorial, demanding more studies that could elucidate the interaction between host and pathogen. The present study aims to evaluate the virulence of 130S. Enteritidis isolates and 70S. Typhimurium inoculated in one-day-old chicks through the establishment of a pathogenicity index. For each strain, 10 commercial chicks from the Cobb lineage were used. Then, 200µL of a solution containing 2x108 CFU of S. Enteritidis or S. Typhimurium were inoculated in the birds by intraperitoneal via. Mortality and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Birds; Salmonelosis; Virulence.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352016000200257

Use of local rice cultivars as additional differentials to identify pathotypes of Pyricularia oryzae
Provedor de dados: 53
Autores: Silva,Gisele Barata da; Araújo,Leila Garcês de; Lobo,Valácia Lemes da Silva; Prabhu,Anne Sitarama; Rêgo,Marcela Cristiane Ferreira; Paes,Eduardo Tavares; Filippi,Marta Cristina Corsi de.
Eight additional rice cultivars as differentials were selected to identify pathotypes occurring in the Tocantins State. They were BRS Jaburu, BRS Taim, BRS Biguá, BR IRGA-417, Epagri 109, Javaé, Metica-1 and Supremo. These differentials were used in addition to the international set to determine the pathogenic diversity of 193 Pyricularia oryzae isolates collected during 1994-2002 from irrigated rice cultivars. They were conserved in Pyricularia culture collection of Embrapa Rice and Bean Research center. From 193 P. oryzae isolates 38 pathotypes were identified based on leaf blast reactions of international set and 29 pathotypes based on these additional differentials. The predominant pathotypes (TI-1, TG-2, TD-15 and TF-2) were represented by 53% of the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Pyricularia grisea; Rice leaf blast; Physiologic races; Oryza sativa; Virulence; Resistance; Differential varieties.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052011000400019

Characterization of Nomuraea rileyi strains using polymorphic DNA, virulence and enzyme activity
Provedor de dados: 52
Autores: Vargas,Lúcia Rosane Bertholdo; Rossato,Marcelo; Ribeiro,Rute Terezinha da Silva; Barros,Neiva Monteiro de.
The characterization of entomopathogenic microorganisms is important for the selection of more effective strains for use in integrated pest-control programs. Five Nomuraea rileyi strains (SA86101, GU87401, SR86151, CG128 and VA9101) were characterized using random amplified polymorphic DNA (RAPD) analysis, virulence studies and assessment of chitinolytic and proteolytic activity. RAPD analysis divided the strains into two groups with a similarity coefficient of 0,76%, group 1 consisting of strains SA86101, GU87401 and SR86151 and group 2 of strains CG128 and VA9101. The LT50 varied from 165h with strain VA9101 to 246h with strain GU87401. Chitinolytic and proteolytic activity of the fungi after 144h growth in minimal medium were tested using colloidal...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Nomuraea rileyi; Anticarsia gemmatalis; Chitinase; Protease; RAPD; Virulence.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132003000100003

Virulence genes and genetic relationship of L. monocytogenes isolated from human and food sources in Brazil
Provedor de dados: 55
Autores: Almeida,Rosana Macedo de; Barbosa,André Victor; Lisbôa,Rodrigo de Castro; Santos,André Felipe das Mercês; Hofer,Ernesto; Vallim,Deyse Christina; Hofer,Cristina Barroso.
ABSTRACT The herein presented assay provided a bacteriological and molecular characterization of 100 samples of L. monocytogenes isolated from human (43) and food (57) sources, from several regions of Brazil, and collected between 1975 and 2013. Antigenic characterization defined 49% of serotype 4b samples, followed by 28% of serotype 1/2b, 14% of serotype 1/2c, 8% of serotype 1/2a, and 1% of serotype 3b. Both type of samples from human and food origin express the same serotype distribution. Multiplex PCR analysis showed 13 strains of type 4b with the amplification profile 4b-VI (Variant I). Virulence genes hly, inlA, inlB, inlC, inlJ, actA, plcA, and prfA were detected in all samples, highlighting a deletion of 105pb on the actA gene in 23% of serotype 4b...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Listeria monocytogenes; Listeriosis; Virulence; Food; PFGE; Brazil.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-86702017000300282

Effects of sub-minimum inhibitory concentrations of ciprofloxacin on biofilm formation and virulence factors of Escherichia coli
Provedor de dados: 55
Autores: Dong,Guofeng; Li,Jiahui; Chen,Lijiang; Bi,Wenzi; Zhang,Xiaoxiao; Liu,Haiyang; Zhi,Xiaoyang; Zhou,Tieli; Cao,Jianming.
ABSTRACT  Objective: To evaluate the influence of sub-minimum inhibitory concentrations (MICs) of ciprofloxacin (CIP) on biofilm formation and virulence factors of Escherichia coli clinical isolates.  Methods: Sub-MICs of CIP were determined using growth curve experiments. The biofilm-forming capacity of E. coli clinical isolates and E. coli ATCC 25922 treated or untreated with sub-MICs of CIP was assessed using a crystal violet staining assay. The biofilm structure of E. coli isolate was assessed with scanning electron microscopy (SEM). The expression levels of the virulence genes fim, usp, and iron and the biofilm formation genes of the pgaABCD locus were measured using quantification RT-PCR (qRT-PCR) in E. coli isolates and E. coli ATCC 25922.  Results:...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Biofilm formation; Ciprofloxacin; Escherichia coli; Sub-minimum inhibitory concentration; Virulence.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-86702019000100015

Next-generation sequencing virulome analysis of a Yersinia enterocolitica subsp. palearctica bioserotype 4/O:3 ST18 isolated from human blood in Brazil
Provedor de dados: 55
Autores: Rusak,Leonardo Alves; Junqueira,Ricardo Magrani; Hofer,Ernesto; Vallim,Deyse Christina; Asensi,Marise Dutra.
Abstract Yersinia enterocolitica is a widespread Gram-negative bacterium that causes gastrointestinal disease and other clinical manifestations in humans. Potentially pathogenic Y. enterocolitica has been isolated in Brazil, from human, environmental, food, and animal sources. Herein we report a genome sequence of Y. enterocolitica subsp. palearctica strain YE 19, serotype O:3, biotype 4, sequence type 18, with virulence determinants isolated from human blood in Rio de Janeiro in 2005. The results corroborate other findings that this strain harbors a set of virulence determinants that could play a role in host pathoadaptation and may also justify the successful dissemination of bioserotype 4/O:3 in Brazil. The presence of strains harboring all of these...
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Yersinia enterocolitica; Virulence; Brazil; Next-generation sequencing.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-86702017000500550

Comparative virulence of Scedosporium species in animal models
Provedor de dados: 55
Autores: Nweze,EI; Okafor,JI.
Scedosporium species are an emerging opportunist group of fungi that have been found to cause infections in both immunocompetent and non-immunocompetent individuals. The infections are not regularly distributed among different countries of the world either because of improper identification or other geographical reasons. Strange as it may, disseminated systemic infections have only been reported in some specific countries. We used a mouse model of disseminated infection to assess if strains from Nigeria were virulent and compared it to a few other strains from other countries. S. apiospermum isolated from Nigeria were clearly less virulent than those obtained elsewhere. This may be the reason why this group of fungi has not been associated with specific...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Scedosporium; Inocula; Virulence; Fungi.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-86702010000300012

A bovine herpesvirus 5 recombinant defective in the thymidine kinase (TK) gene and a double mutant lacking TK and the glycoprotein E gene are fully attenuated for rabbits
Provedor de dados: 56
Autores: Silva,S.C.; Brum,M.C.S.; Weiblen,R.; Flores,E.F.; Chowdhury,S.I.
Bovine herpesvirus 5 (BoHV-5), the agent of herpetic meningoencephalitis in cattle, is an important pathogen of cattle in South America and several efforts have been made to produce safer and more effective vaccines. In the present study, we investigated in rabbits the virulence of three recombinant viruses constructed from a neurovirulent Brazilian BoHV-5 strain (SV507/99). The recombinants are defective in glycoprotein E (BoHV-5gEΔ), thymidine kinase (BoHV-5TKΔ) and both proteins (BoHV-5gEΔTKΔ). Rabbits inoculated with the parental virus (N = 8) developed neurological disease and died or were euthanized in extremis between days 7 and 13 post-infection (pi). Infectivity was detected in several areas of their brains. Three of 8 rabbits inoculated with the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: BoHV-5; GE and TK deletion mutants; Pathogenesis; Virulence; Vaccine candidate.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2010000200005

Characterization of the virulence, growth temperature and antibiotic resistance of the Campylobacter jejuni IAL 2383 strain isolated from humans
Provedor de dados: 58
Autores: Fonseca,B.B.; Rossi,D.A.; Maia,C.A.; Nalevaiko,P.C.; Melo,R.T.; Cuccato,L.P.; Beletti,M.E.
The objective of this study was to characterize the C. jejuni IAL2383 strain isolated from humans in Brazil. Transcripts for the racR, dnaJ and ciaB genes were found and flaA, plda and cadF genes were present in the genome and bacteria was sensitive to most of the important antimicrobials used to treat humans. C. jejuni IAL2383 is a good experimental model to analyze the interactions with cells.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Virulence; Experimental model; Thermotolerance; Campylobacter jejuni.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822014000100039

Expression of aggregative adherence to hela cells by Escherichia coli strains isolated from sick horses
Provedor de dados: 58
Autores: Liberatore,Ana Maria Alvim; Tomita,Sandra Kimie; Vieira,Mônica Aparecida Midolli; Toti Jr.,Cyro; Heckmaier,João; Gomes,Tânia Aparecida Tardelli.
The virulence attributes of 56 Escherichia coli strains isolated from sick horses (secretions of uterine cervices; gastrointestinal and lung fragments of necropsy; diarrheic feces, and tracheal washings) was examined by determining their adherence pattern to HeLa cells and searching for the presence of virulence genes of the various E. coli pathotypes. Two non-adherent strains presented astA, which encodes the enteroaggregative E. coli heat-stable toxin. Twenty-seven strains (48.2%) adhered to HeLa cells, 21 (77.8%) of which presented the aggregative adherence pattern (AA) that characterize the Enteroaggregative E. coli pathotype (EAEC). Nine of the strains presenting AA were isolated from secretions of uterine cervix, including one carrying virulence...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Horse; Escherichia coli; Aggregative adherence; Virulence.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822007000100003

Inactivation of phoPQ genes attenuates Salmonella Gallinarum biovar Gallinarum to susceptible chickens
Provedor de dados: 58
Autores: Alves,Lucas Bocchini Rodrigues; Freitas Neto,Oliveiro Caetano de; Batista,Diego Felipe Alves; Barbosa,Fernanda de Oliveira; Rubio,Marcela da Silva; Souza,Andrei Itajahy Secundo de; Almeida,Adriana Maria de; Barrow,Paul Andrew; Berchieri Junior,Angelo.
Abstract Salmonella Gallinarum is a host-restrict pathogen that causes fowl typhoid, a severe systemic disease that is one of the major concerns to the poultry industry worldwide. When infecting the bird, SG makes use of evasion mechanisms to survive and to replicate within macrophages. In this context, phoPQ genes encode a two-component regulatory system (PhoPQ) that regulates virulence genes responsible for adaptation of Salmonella spp. to antimicrobial factors such as low pH, antimicrobial peptides and deprivation of bivalent cations. The role of the mentioned genes to SG remains to be investigated. In the present study a phoPQ-depleted SG strain (SG ΔphoPQ) was constructed and its virulence assessed in twenty-day-old laying hens susceptible to fowl...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mutation; Virulence; Fowl typhoid; Adaptation; Chickens.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822018000300601

Model of experimental infection in healthy and immunosuppressed swiss albino mice (Mus musculus) using Candida albicans strains with different patterns of enzymatic activity
Provedor de dados: 58
Autores: Chaves,Guilherme M.; Cavalcanti,Maria Auxiliadora de Q.; Carneiro-Leão,Ana Maria dos A.; Lopes,Silvia L.
With the purpose to evaluate Candida albicans virulence in vivo, two strains selected were based on their phospholipase and proteinase activity, and used in a model of experimental infection. One strain, isolated from vaginal secretion, was stocked at the URM Culture Collection for 43 years and presented high phospholipase (Pz=0.217) and proteinase (1.386 U.mL-1) activity. The other strain was a fresh strain isolated from oropharyngeal secretion of an AIDS patient, and presented low phospholipase (Pz=0.482) and proteinase (0.780 U.mL-1) activity. The strains were inoculated via intraperitoneum in immunosuppressed and non-immunosuppressed mice (Mus musculus) and the infection was evaluated over a period of 21 days. Liver, spleen, lungs and kidneys were...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Candida albicans; Extracellular enzymes; Virulence; Experimental infection.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822004000300010

Biotyping and genotypic diversity among oral Candida albicans strains from caries-free and caries-active healthy children
Provedor de dados: 58
Autores: Mardegan,Rita de Cássia; Klein,Marlise Inêz; Golvea,Magda Baglione; Rodrigues,Janaina Aparecida Oliveira; Gonçalves,Reginaldo Bruno; Höfling,José Francisco.
Candida albicans oral strains collected from caries-free and caries-active healthy children ranging from 24 to 36 months old, were studied. The aim of the study was to determine proteinase and phospholipase activities produced by Candida albicans in the two groups and to determine the phenotypic diversity of these enzymes based on genetic polymorphism using the AP-PCR method. Strains identified by morphological and fermentation tests as C. albicans were grown in proteinase and phospholipase agar media at 37ºC for 7 and 4 days, respectively. After the incubation period, the enzyme activity of the proteinase and phospholipase positive strains was measured. All strains were subjected to AP-PCR, using the arbitrary primer AP-3. The enzymatic analysis showed no...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Candida albicans; Genotyping; Proteinase; Phospholipase; Virulence.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822006000100005

Carbapenem-resistant Pseudomonas aeruginosa: association with virulence genes and biofilm formation
Provedor de dados: 58
Autores: Gonçalves,Iara Rossi; Dantas,Raquel Cristina Cavalcanti; Ferreira,Melina Lorraine; Batistão,Deivid William da Fonseca; Gontijo-Filho,Paulo Pinto; Ribas,Rosineide Marques.
Abstract Pseudomonas aeruginosa is an opportunistic pathogen that causes frequently nosocomial infections, currently becoming more difficult to treat due to the various resistance mechanisms and different virulence factors. The purpose of this study was to determine the risk factors independently associated with the development of bacteremia by carbapenem-resistant P. aeruginosa, the frequency of virulence genes in metallo-β-lactamases producers and to evaluate their ability to produce biofilm. We conducted a case–control study in the Uberlândia Federal University – Hospital Clinic, Brazil. Polymerase Chain Reaction was performed for metallo-β-lactamases and virulence genes. Adhesion and biofilm assays were done by quantitative tests. Among the 157 strains...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Pseudomonas aeruginosa; Resistance; Metallo-β-lactamases; Virulence; Biofilm.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822017000200211

The virulence of Streptococcus pneumoniae partially depends on dprA
Provedor de dados: 58
Autores: Yu,Yi; Chang,De; Xu,Huiwen; Zhang,Xuelin; Pan,Lei; Xu,Chou; Huang,Bing; Zhou,Hong; Li,Jia; Guo,Jun; Liu,Changting.
Abstract Streptococcus pneumoniae is one of the most frequent opportunistic pathogens worldwide. DNA processing protein A (DprA) is an important factor involved in bacterial uptake and DNA integration into bacterial genome, but its role in S. pneumoniae virulence remains unclear. The aim of this study was to characterize the effects of the pneumococcal dprA gene on the pathogenesis of S. pneumoniae. To construct a dprA-deficient pneumococcal strain, the dprA gene of the S. pneumoniae strain D39 was inactivated. The virulence of this dprA-deficient strain, designated ΔD39, was compared with that of the wild-type strain by evaluating their respective capabilities to adhere to human pulmonary epithelial cells (PEC-A549) and by analyzing their choline-binding...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Streptococcus pneumoniae; DprA; Transformation; Virulence.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822017000200225

Characterization and comparison of Serratia marcescens isolated from edible cactus and from silkworm for virulence potential and chitosan susceptibility
Provedor de dados: 58
Autores: Li,Bin; Yu,Rongrong; Liu,Baoping; Tang,Qiaomei; Zhang,Guoqing; Wang,Yanli; Xie,Guanlin; Sun,Guochang.
Representative strains of Serratia marcescens from an edible cactus plant and silkworms were characterized and a comparison based on their cellular fatty acid composition, 16S rRNA and groE gene sequence analysis as well as silkworm virulence and chitosan susceptibility was carried out. Results from this study indicate that there are no significant differences between the phenotypic and molecular characterization, virulence and chitosan susceptibility of the S. marcescens strains from the cactus plant and silkworms. Silkworms inoculated with S. marcescens from either plant or silkworm resulted in nearly 100% mortality. Chitosan solution exhibited strong antibacterial activity against S. marcescens. This activity increased with the increase of chitosan...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Serratia marcescens; Cactus; Silkworm; Characterization; Virulence; Chitosan susceptibility.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822011000100013

Influence of carvacrol and thymol on the physiological attributes, enterotoxin production and surface characteristics of Staphylococcus aureus strains isolated from foods
Provedor de dados: 58
Autores: Souza,E.L.; Oliveira,C.E.V.; Stamford,T.L.M.; Conceição,M.L.; Gomes Neto,N.J.
This study evaluated the influence of the phenolic compounds carvacrol (CAR) and thymol (THY) on some physiological characteristics and on the modulation of the secretion of some staphylococcal virulence factors, that is, coagulase and enterotoxin. This study also investigated possible mechanisms for the establishment of the anti-staphylococcal activity of these compounds. Sublethal concentrations (0.3 and 0.15 µL/mL) of CAR and THY inhibited the activity of the enzymes coagulase and lipase and led to a decrease in salt tolerance. At the tested sublethal concentrations, both CAR and THY led to a total suppression of enterotoxin production. The loss of a 260-nm-absorbing material and an efflux of potassium ions occurred immediately after the addition of CAR...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Phenolic compounds; Physiological suppression; Staphylococcal enterotoxins; Virulence.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822013000100004

Virulence and cytotoxicity of seafood borne Aeromonas hydrophila
Provedor de dados: 58
Autores: Illanchezian,Seethalakshmi; Jayaraman,SathishKumar; Manoharan,Muthu Saravanan; Valsalam,Saritha.
The present study was conducted to determine the virulence and cytotoxicity of Aeromonas hydrophila strains isolated from seafood samples collected from 5 major fish markets in Chennai, Tamil Nadu, India. Among 73 A. hydrophila strains isolated from fish and shrimp samples, 86.3% exhibited haemolysis, 78.1% produced slime, 98.63% produced protease and also demonstrated cytotoxicity on Vero cells. Cell shrinkage, detachment and rounding of Vero cells were recorded as cytotoxic changes. Only one strain did not show haemolysis, slime production, proteolytic activity and cytotoxicity on treatment with Vero cells. Positive correlation was observed between proteolytic activity and cytotoxicity irrespective of haemolytic activity of the strains. These results...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Aeromonas hydrophila; Seafood; Virulence; Cytotoxicity; Vero cells.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822010000400016

Community-associated methicillin-resistant Staphylococcus aureus in non-outbreak skin infections
Provedor de dados: 58
Autores: Bonesso,Mariana Fávero; Marques,Silvio Alencar; Camargo,Carlos Henrique; Fortaleza,Carlos Magno Castelo Branco; Cunha,Maria de Lourdes Ribeiro de Souza da.
The aim of this study was to determine the prevalence of Staphylococcus aureus and risk factors for the acquisition of MRSA (Methicillin Resistant Staphylococcus aureus) as the main cause of skin and soft tissue infections. S. aureus were characterized for the presence of PVL, TSST-1 and mecA genes. SCCmec typing was carried out in mecA positive strains and PFGE was performed only in these strains. During the study period, 127 outpatients attending a dermatology clinical the Botucatu Medical School, a regional tertiary hospital in Botucatu, Sao Paulo, Brazil, were diagnosed with active skin infections. A total 66 (56.9%) S. aureus strains were isolated. The methicillin resistance gene mecA was detected in seven (10.6%) S. aureus strains. The SCCmec types...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Staphylococcus aureus; Resistance; Skin infections; Virulence; Epidemiology.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822014000400034

Detection of virulence and β-lactamase encoding genes in Enterobacter aerogenes and Enterobacter cloacae clinical isolates from Brazil
Provedor de dados: 58
Autores: Azevedo,Paola Aparecida Alves; Furlan,João Pedro Rueda; Oliveira-Silva,Mariana; Nakamura-Silva,Rafael; Gomes,Carolina Nogueira; Costa,Karen Regina Carim; Stehling,Eliana Guedes; Pitondo-Silva,André.
ABSTRACT Enterobacter cloacae and E. aerogenes have been increasingly reported as important opportunistic pathogens. In this study, a high prevalence of multi-drug resistant isolates from Brazil, harboring several β-lactamase encoding genes was found. Several virulence genes were observed in E. aerogenes, contrasting with the E. cloacae isolates which presented none.
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Enterobacter cloacae; Enterobacter aerogenes; Virulence; Resistance.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822018000500224

Prevalence of virulence genes in strains of Campylobacter jejuni isolated from human, bovine and broiler
Provedor de dados: 58
Autores: González-Hein,Gisela; Huaracán,Bernardo; García,Patricia; Figueroa,Guillermo.
Campylobacter jejuni isolates of different origins (bovine, broiler meat, human) were screened by polymerase chain reaction for the presence of 4 genes cdtB, cst-II, ggt, and virB11, previously linked to virulence such as adherence, invasion, colonization, molecular mimicry, and cytotoxin production. In addition, the isolates were screened for the presence of the global gene regulator csrA linked to oxidative stress responses, biofilms formation, and cell adhesion. All the C. jejuni isolates were positive for cdtB gene. The csrA gene was detected in 100% and 92% of C. jejuni isolates from human and animal origin and the virB11 gene was detected in 7.3% and 3.6% isolates from chicken and human respectively. All isolates from bovine were negative for the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Campylobacter jejuni; Virulence; Guillain Barré syndrome; Broiler; Bovine.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822013000400028

Identification of pathogens and virulence profile of Rhodococcus equi and Escherichia coli strains obtained from sand of parks
Provedor de dados: 58
Autores: Fernandes,M.C.; Takai,S.; Leite,D.S.; Pinto,J.P.A.N.; Brandão,P.E.; Santarém,V.A.; Listoni,F.J.P.; Silva,A.V. Da; Ribeiro,M.G.
The identification of pathogens of viral (Rotavirus, Coronavirus), parasitic (Toxocara spp.) and bacterial (Escherichia coli, Salmonella spp., Rhodococcus equi) origin shed in feces, and the virulence profile of R. equi and E. coli isolates were investigated in 200 samples of sand obtained from 40 parks, located in central region of state of Sao Paulo, Brazil, using different diagnostic methods. From 200 samples analyzed, 23 (11.5%) strains of R. equi were isolated. None of the R. equi isolates showed a virulent (vapA gene) or intermediately virulent (vapB gene) profiles. Sixty-three (31.5%) strains of E. coli were identified. The following genes encoding virulence factors were identified in E. coli: eae, bfp, saa, iucD, papGI, sfa and hly. Phylogenetic...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Enteric pathogens; Virulence; Sand; Feces; Parks; E. coli; R. equi.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822013000200025

Virulence potential and antibiotic susceptibility pattern of motile aeromonads associated with freshwater ornamental fish culture systems: a possible threat to public health
Provedor de dados: 58
Autores: Sreedharan,Krishnan; Philip,Rosamma; Singh,Isaac Sarojani Bright.
Aeromonas spp. are ubiquitous aquatic organisms, associated with multitude of diseases in several species of animals, including fishes and humans. In the present study, water samples from two ornamental fish culture systems were analyzed for the presence of Aeromonas. Nutrient agar was used for Aeromonas isolation, and colonies (60 No) were identified through biochemical characterization. Seven clusters could be generated based on phenotypic characters, analyzed by the programme NTSYSpc, Version 2.02i, and identified as: Aeromonas caviae (33.3%), A. jandaei (38.3%) and A. veronii biovar sobria (28.3%). The strains isolated produced highly active hydrolytic enzymes, haemolytic activity and slime formation in varying proportions. The isolates were also...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Aeromonas; Antibiotic susceptibility; Ornamental fish culture systems; Virulence.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822012000200040

Carum copticum and Thymus vulgaris oils inhibit virulence in Trichophyton rubrum and Aspergillus spp
Provedor de dados: 58
Autores: Khan,Mohd Sajjad Ahmad; Ahmad,Iqbal; Cameotra,Swaranjit Singh.
Emergence of drug-resistant strains has demanded for alternative means of combating fungal infections. Oils of Carum copticum and Thymus vulgaris have long been used in ethnomedicine for ailments of various fungal infections. Since their activity has not been reported in particular against drug-resistant fungi, this study was aimed to evaluate the effects of oils of C. copticum and T. vulgaris on the growth and virulence of drug-resistant strains of Aspergillus spp. and Trichophyton rubrum. The gas chromatography-mass spectrometry analysis revealed thymol constituting 44.71% and 22.82% of T. vulgaris and C. copticum, respectively. Inhibition of mycelial growth by essential oils was recorded in the order of thymol &gt; T. vulgaris &gt; C. copticum against...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Anti-elastase activity; Arthroconidia; Synergy; Thymol; Virulence.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822014000200021

Detection of virulence genes in Salmonella Enteritidis isolated from different sources
Provedor de dados: 58
Autores: Oliveira,Sílvia Dias de; Rodenbusch,Carla Rosane; Michael,Geovana B.; Cardoso,Marisa I.R.; Canal,Cláudio Wageck; Brandelli,Adriano.
The presence of three virulence genes, invA, spvR, and spvC, was determined in Salmonella Enteritidis isolated from poultry, pigs, humans and food. All isolates were positive for the invA gene, with 91.2% being positive for spvR and 90.2% for spvC. There was no significant difference in the prevalence of the virulence genes between isolates from different sources. The results indicate that there is a putative high virulence potential for the S. Enteritidis isolates characterized.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Salmonella Enteritidis; Virulence; Spv; PCR.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822003000500042

Helicobacter pylori with East Asian-type cagPAI genes is more virulent than strains with Western-type in some cagPAI genes
Provedor de dados: 58
Autores: Yuan,Xiao-yan; Yan,Jin-Jun; Yang,Ya-chao; Wu,Chun-mei; Hu,Yan; Geng,Jian-li.
Abstract The severity of Helicobacter pylori-related disease is correlated with the presence and integrity of a cag pathogenicity island (cagPAI). cagPAI genotype may have a modifying effect on the pathogenic potential of the infecting strain. After analyzing the sequences of cagPAI genes, some strains with the East Asian-type cagPAI genes were selected for further analysis to examine the association between the diversity of the cagPAI genes and the virulence of H. pylori. The results showed that gastric mucosal inflammatory cell infiltration was significantly higher in patients with East Asian-type cagPAI genes H. pylori strain compared with mosaicism cagPAI genes H. pylori strain (p &lt; 0.05). H. pylori strains with the East Asian-type cagPAI genes were...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Helicobacter pylori; CagPAI; Virulence; IL-8.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822017000200218

Evaluation of bacteriocin-producing Lactobacillus sakei 1 against Listeria monocytogenes 1/2a growth and haemolytic activity
Provedor de dados: 58
Autores: Martinez,Rafael C.R.; De Martinis,Elaine C.P.
Bacteriocin-producing Lactobacillus sakei 1 was cultivated in Brain-Heart Infusion broth (24 h at 25ºC). The culture supernatant was neutralized, filter sterilized and used to test the activity of bacteriocin against Listeria monocytogenes 1/2a, at 8ºC and 15ºC. Non-bacteriocinogenic Lactobacillus sakei ATCC 15521 was used as a negative control. L. monocytogenes 1/2a was inoculated in culture supernatant medium from L. sakei 1 and L. sakei ATCC 15521 and the listerial populations were determined after 0, 5 and 10 days. The bacteriocin production was quantified as arbitrary units per mL (AU/mL) using agar antagonism test. Additionally, to investigate if L. monocytogenes virulence pattern could be changed after bactericion exposure, the ability of L....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Listeria monocytogenes; Lactobacillus sakei; Bacteriocins; Virulence; Resistance.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822005000100016

Expression of virulence genes by Listeria monocytogenes J0161 in natural environment
Provedor de dados: 58
Autores: Tirumalai,Prem Saran; Prakash,Soam.
Majority of studies concerning the gene expression of Listeria monocytogenes have been done on pure culture states. Our objective was to study L.monocytogenes in a co-cultured state and to understand if microbes in their natural state of existence are different in their expression than that of the purely cultured lab grown forms. For a long period discussions have been on the expression of prfA, (which is a virulence gene regulator) in a mammalian host and its role in causing the switch from a saprophytic to pathogenic form of L.monocytogenes. We, in this paper for the first time report the expression of prfA and other virulence genes by L.monocytogenes under different extracellular conditions, and also as a pure culture biofilms, that is different from...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Listeria monocytogenes; PrfA; Virulence; Microarray; Biofilms; Co-culture; Gene Expression.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822012000200050

Candida albicans morphologies revealed by scanning electron microscopy analysis
Provedor de dados: 58
Autores: Staniszewska,M.; Bondaryk,M.; Swoboda-Kopec,E.; Siennicka,K.; Sygitowicz,G.; Kurzatkowski,W.
Scanning electron microscope (SEM) observations were used to analyze particular morphologies of Candida albicans clinical isolate (strain 82) and mutants defective in hyphae-promoting genes EFG1 (strain HLC52) and/ or CPH1 (strains HLC54 and Can16). Transcription factors Efg1 and Cph1 play role in regulating filamentation and adhesion of C. albicans' morphologies. Comparative analysis of such mutants and clinical isolate showed that Efg1 is required for human serum-induced cell growth and morphological switching. In the study, distinct differences between ultrastructural patterns of clinical strain's and null mutants' morphologies were observed (spherical vs tube-like blastoconidia, or solid and fragile constricted septa vs only the latter observed in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Candida albicans; Pleomorphism; Ultrastructure; Virulence.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822013000300023

Effect of virulence and serial transfers of Xanthomonas campestris on xanthan gum production
Provedor de dados: 58
Autores: Nitschke,Marcia; Rodrigues,Vanessa.
The virulence of six Xanthomonas campestris isolates was evaluated using the percentage of lesion area of leaves in Brassica oleraceae host plant, compared to diameter of colonies, xanthan production and gum viscosity. In terms of virulence, the isolates belonged to two statistically different groups: isolates B, UPF and C7 showed values between 52 and 69%, while isolates CF, C and strain B-1459 gave 0-30% of lesion area. Final xanthan concentration, gum viscosity and colony diameter did not correlate with virulence calculated by percentage of lesion area, showing that this parameter is not a good criterium for selection of potential xanthan producer isolates. Serial transfers of X. campestris isolates in host plant did not show a significant effect on "in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Xanthomonas campestris; Serial transfers; Virulence; Xanthan.
Ano: 2000
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822000000100014

Supplanting resistance of the Mi gene by root-knot nematode in industrial tomato in the Cerrado in Goiás State of Brazil
Provedor de dados: 65
Autores: Silva,Rodrigo Vieira da; Lima,Brenda Ventura de; Peixoto,Fabricio Rodrigues; Gondim,João Pedro Elias; Miranda,Bruno Eduardo Cardoso de.
ABSTRACT:  Problems with root-knot nematodes, caused by genus Meloidogyne, can be controlled through the introduction of resistance genes in commercial varieties of tomatoes. However, plants of the hybrid ‘Heinz 9992’ for industrial processing, carrying the Mi gene, were reported with their roots severely infected in experimental cultivation in Goiás State of Brazil with symptoms typical of galls caused by Meloidogyne spp. After dissecting the galls present in the root samples, the females of the nematodes were removed and afterwards, performed the analysis of the perineal pattern and the biochemical characterization by electrophoresis of isoenzymes, besides the pathogenicity test. The pathogen analyzed was identified as Meloidogyne incognita. The...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Solanum lycopersicum; Meloidogyne incognita; Virulence; Vegetables.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782019000900151