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Registros recuperados: 159
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A light- and electron microscopic study of primordial germ cells in the zebra fish (Danio rerio) Biol. Res.
Deniz Koç,Nazan; Yüce,Rikap.
In sexually reproducing organisms, primordial germ cells (PGCs) give rise to the cells of the germ line, the gametes. In many animals, PGCs are set apart from somatic cells early during embryogenesis. This study explores the origin of primordial germ cells (PGCs) of the zebra fish and examines their morphology during early development (1st day-15th day). PGCs were selectively stained by the alkaline phosphatase histochemical reaction and viewed by light and electron microscopy from the time they are first detectable in the yolk sac endoderm. PGCs occurred in the subendodermal space on the syncytial periblast; differing from the surrounding endodermal cells. Later the PGCs moved to between the blastoderm and yolk sac and transferred to the dorsal mesentery...
Tipo: Journal article Palavras-chave: Primordial germ cell; Zebra fish; Ultrastructure; Morphology.
Ano: 2012 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602012000400001
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A reduced, yet functional, nectary disk integrates a complex system of floral nectar secretion in the genus Zeyheria (Bignoniaceae) Acta Botanica
Machado,Silvia Rodrigues; Souza,Camila Vaz de; Guimarães,and Elza.
ABSTRACT The genus Zeyheria (Bignoniaceae) comprises only two species, both of which have been described as possessing a reduced and non-functional nectary disk. Despite the importance of this evolutionary change in the floral nectary, these functional assumptions have been based on disk size and on the distribution, abundance and histochemistry of corolla-borne trichomes. By combining methods on light and electron microscopy, here we investigated the functionality of the reduced nectary disk and describe all of the tissues and structures of the nectar chamber in order to determine the sites of floral nectar secretion in both Zeyheria species. . Our data find the floral nectary traits of both species to be very similar, although differing in their cellular...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Bignoniaceae; Floral nectary; Functional anatomy; Histochemistry; Ultrastructure.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062017000300344
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Action of cobra venom on the renal cortical tissues: electron microscopic studies J. Venom. Anim. Toxins
RAHMY,T. R..
The effect of intramuscular (IM) injection of a sub-lethal dose of Naja haje cobra venom (0.015 mug/gm body weight) on the ultrastructure of renal cortical tissues of rabbits was studied at different time intervals after envenomation. Succinic dehydrogenase (SDH) enzyme activity was also detected in the renal cortical tubules. Three hours after venom injection, slight changes were seen in visceral cells and glomerular endothelia. The cortical tubular epithelia revealed an increase of lysosomal structures, cytoplasmic vacuolization, and nuclear irregularity. Severe ultrastructural changes were recorded 6 hours after envenomation, including hypertrophied parietal cells, blebbed visceral epithelial cells, and foot process disorganization. Dilated glomerular...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Snake venom; Nephrotoxicity; Kidney; Ultrastructure.
Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-79302001000100007
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An ultrastructural study of spermiogenesis in two species of Sitophilus: Coleoptera: Curculionidae Biocell
Name,Khesller Patrícia Olázia; Dos Reis,Giuliano Pagy Felipe; Báo,Sônia Nair.
The spermiogenesis of Sitophilus zeamais and Sitophilus oryzae, the maize and the rice weevil, respectively, was studied by light microscopy and scanning and transmission electron microscopy. Sitophilus spp. is the most widespread and destructive primary pest of stored cereals in the world. The spermiogenesis occurs within cysts. There are approximately 256 germ line cells per cyst. Inside each cysts, all the spermatids are in the same stage of maturation. The ultrastructure of the spermatozoa of S. zeamais and S. oryzae is similar to that described for other beetles. The head is formed by a three-layered acrosome with the perforatorium, the acrosomal vesicle, the extra-acrosomal layer and the nucleus. The flagellum has the typical axoneme formed by a...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Curculionidae; Sitophilus; Spermiogenesis; Insect sperm; Ultrastructure.
Ano: 2007 URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0327-95452007000200005
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Análise ultra-estrutural de folhas de três espécies de Solanaceae após inoculação com o vírus da necrose branca do tomateiro (VNBT - Tymovirus) Rev. Bras. Bot.
TANAKA,FRANCISCO ANDRÉ OSSAMU; MACHADO,SÍLVIA RODRIGUES; BARRADAS,MARIA MÉRCIA.
Foi estudada a ultra-estrutura foliar das solanáceas Nicotiana glutinosa L., Lycopersicon pimpinellifolium L. e Physalis angulata L. inoculadas com o vírus da necrose branca do tomateiro (VNBT - Tymovirus). As plantas mantidas em casa-de-vegetação com temperatura constante de 25 °C foram inoculadas quando apresentavam três a quatro folhas totalmente expandidas. Quinze dias após a inoculação, foram coletadas amostras do terço médio do limbo da 3ª ou da 4ª folha a partir do ápice. As amostras foram preparadas para análise em microscopia eletrônica de transmissão segundo técnicas convencionais. A análise ultra-estrutural das células do clorênquima revelou principalmente vesiculação e vacuolação dos cloroplastos e de mitocôndrias, além da ocorrência de corpos...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Tymovirus; TWNV; Solanaceae; Leaf; Ultrastructure.
Ano: 2000 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042000000200006
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Anatomical and ultrastructural aspects of root and mycorrhiza of Anadenanthera peregrina (L.) Speg. var. falcata (Benth.) Altschul (Leguminosae-Mimosoideae) Rev. Bras. Bot.
Gross,Eduardo; Cordeiro,Lázara; Caetano,Flávio H..
A. peregrina var. falcata form mutualistic symbiosis with arbuscular mycorrhizal fungus. An anatomical and ultrastructural study was carried out to analyze some aspects of this simbiotic association as well as some root features. The results evidenced the presence of fibers with non-lignified thicked secondary walls in the stele and sparse papillae on root surface. A. peregrina var. falcata mycorrhizas presented features of Arum-type (intercellular hyphae) and Paris-type (extensive coils) arbuscular mycorrhiza. Their general appearance with extraradical hyphae, intracellular coils, intercellular hyphae and arbuscules, is in agreement with arbuscular mycorrhizas of several plants. The ultrastructural observations showed that in intercellular hyphae and...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Anadenanthera peregrina var. falcata; Anatomy; Mycorrhiza; Root; Ultrastructure.
Ano: 2003 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042003000400010
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Anatomy and ontogeny of the pericarp of Pterodon emarginatus Vogel (Fabaceae, Faboideae), with emphasis on secretory ducts Anais da ABC (AABC)
Paiva,Élder A.S.; Oliveira,Denise M.T.; Machado,Silvia R..
Discrepant and incomplete interpretations of fruits of Pterodon have been published, especially on the structural interpretation of the pericarp portion that remain attached to the seed upon dispersal. The present work clarified these doubts and analyzed ultrastructural aspects of the Pterodon emarginatus diaspores using light and transmission electron microscopes. Cell divisions are prevalent among the initial phases of development, and the subadaxial and adaxial meristems form the fibrous inner mesocarp and the endocarp composed of multi-seriate epidermis, respectively. At the median mesocarp, numerous secretory ducts differentiate between the lateral bundles, by lytic process. After lysis of the central cells and the formation of the lumen, the ducts...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Pterodon emarginatus; Development; Fruit; Secretory duct; Resin; Ultrastructure.
Ano: 2008 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652008000300007
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Anatomy, ultrastructure and secretion of Hibiscus pernambucensis Arruda (Malvaceae) extrafloral nectary Rev. Bras. Bot.
Rocha,Joecildo Francisco; Machado,Silvia Rodrigues.
This paper reports on the extrafloral nectary (EFN) of Hibiscus pernambucensis, a native shrub species occurring in mangrove and restinga along Brazil's coastline. EFNs occur as furrows with a protuberant border on the abaxial surface veins of the leaf blade. Each nectary consists of numerous secretory multicellular trichomes, epidermal cells in palisade-like arrangements and non-vascularized parenchyma tissue. Nectar secretion is prolonged, since secretion starts in very young leaves and remains up to completely expanded leaves. Reduced sugars, lipids, and proteins were histochemically detected in all the nectary cells; phenolic substances were detected in the vacuoles of the epidermal palisade cells and in some secretory trichome cells. The secretory...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Anatomy; Extrafloral nectary; Hibiscus pernambucensis; Histochemistry; Ultrastructure.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042009000300008
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Approche ecophysiologigue et ultrastructurale de l'osmoregulation chez les crustaces decapodes ArchiMer
Pequeux, A; Lignon, J.
This paper deals mostly with recent physiological data on ion transport across the gill tissue and an attempt is made to correlate them with blood osmoregulation and ecological distribution in euryhaline decapods. A particular attention is paid to the gills of the fully euryhaline Chinese crab Eriocheir sinensis . Supporting this ecophysiological approach, there is an important ultrastructural analysis of the gill epithelium under various salinity conditions. The possible part played by the cuticle in ions movements is also considered.
Tipo: Text Palavras-chave: Eriocheir sinensis; Cancer pagurus; Maia squinado; Carcinus maenas; Decapoda; Malacostraca; Ion transport; Gills; Ecophysiology; Cuticles; Ultrastructure; Salinity tolerance.
Ano: 1987 URL: http://archimer.ifremer.fr/doc/1987/acte-1387.pdf
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Aspectos ultraestruturais do espermatozóide de Natica marochiensish (Gmelin) (MOllusca, Gastropoda) do litoral norte do Brasil Zoologia
Matos,Edilson; Matos,Patricia; Casal,Graça; Azevedo,Carlos.
Spermatozoa of Natica marochienssish (Gmelin, 1791) is described by light and electron microscopy. The spermatozoon is of the primitive type with head contains a conical acrosomal complex with an acrosomal vesicle of dense matrix having a basis occupied by the subacrosomal space. The middle piece shows the centriolar complex surrounded by mitochondria and the tail contains the axoneme with a 9+2.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Mollusca; Gastropoda; Natica marochiensish; Ultrastructure; Spermatozoa.
Ano: 1997 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81751997000300009
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Aspects ultrastructuraux de la biodegradation de l''ancienne cuticule de Carcinus maenas durant la periode preecdysiale ArchiMer
Thorez, A; Compere, P; Goffinet, G.
Ultrastructural observations of various integumental regions of the crab Carcinus maenas show an important biodegradation of the old sclerites during premolt. At the ecdysis, this biodegradation extends from the basis of the membranous layer up the upper third of the principal layer. The first biodegradation features are a disorganization followed by a complete disappearance of the microfibrils. Numerous ecdysial droplets and double membrane bounded microstructures probably take part in biodegradation processes.
Tipo: Text Palavras-chave: Carcinus maenas; Malacostraca; Ultrastructure; Moulting; Biodegradation.
Ano: 1987 URL: http://archimer.ifremer.fr/doc/1987/acte-1376.pdf
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Bonamia exitiosus n. sp (Haplosporidia) infecting flat oysters Ostrea chilensis in New Zealand ArchiMer
Hine, P; Cochennec, Nathalie; Berthe, Franck.
Bonamia sp. is a pathogenic parasite that occurs in the haemocytes of dredge oysters Ostrea chilensis Philippi in New Zealand, Ultrastructurally it resembles other haplosporidians in the possession of haplosporosomes, haplosporogenesis, persistence of mitotic microtubules during interphase and of the nuclear envelope during mitosis, and occurrence of a diplokaryotic or multi-nucleate plasmodial stage. Another stage containing a large vacuole derived from enlargement of 1 or more mitochondria has not previously been described from other haplosporidians. It most closely resembles B, ostreae Pichot et al., 1979, which parasitises and is pathogenic in haemocytes of European flat oysters, O. edulis. However, B. ostreae is smaller and denser, and has fewer...
Tipo: Text Palavras-chave: New Zealand; 18S rDNA; Ultrastructure; Ostrea chilensis; Bonamia exitiosus.
Ano: 2001 URL: http://archimer.ifremer.fr/doc/2001/publication-818.pdf
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Bovine conceptus of Bos indicus produced by somatic cell nuclear transfer and parthenogenesis present morphological variations since the blastocyst stage Arq. Bras. Med. Vet. Zootec.
Oliveira,F.D.; Sangalli,J.R.; Meirelles,F.V.; Perecin,F.; Silva Filho,P.P.C.; Watanabe,Y.F.; Miglino,M.A.; Assis Neto,A.C..
In cattle, embryo development is characterized by the appearance of two distinct cell layers, the trophectoderm and the inner cell mass. The latter will undergo differentiation to form the embryonic disc consisting of the epiblast and hypoblast. The aim of this study was to ultrastructurally characterize the bovine embryo from different in vitro production techniques, with emphasis on trophectoderm and inner cell mass cells. Bovine embryos on day 7 (conception = D1) of pregnancy, derived via in vitro production techniques, were fixed for light and transmission electron microscopy processing. Results suggested that embryos produced by nuclear transfer of somatic cells and parthenogenesis showed significant changes in macroscopic and microscopic structure....
Tipo: Info:eu-repo/semantics/article Palavras-chave: Embryo; Blastocyst; In vitro production; Ultrastructure.
Ano: 2015 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352015000601483
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Bulliform cells in Loudetiopsis chrysothrix (Nees) Conert and Tristachya leiostachya Nees (Poaceae): structure in relation to function BABT
Alvarez,Juliana Magalhães; Rocha,Joecildo Francisco; Machado,Silvia Rodrigues.
This work reports anatomic and ultrastructural characteristics of bulliform cells in Loudetiopsis chrysothrix (Nees) Conert and Tristachya leiostachya Nees. Both the species presented leaf rolling under water stress. The main characteristics observed in these cells were: periclinal wall thinner than the adjacent epidermal wall; abundance of pectic substances in cuticular layer; sinuous anticlinal walls with ramified plasmodesmata; vacuome formed by a developed vacuole or innumerous small vacuoles; abundance of phenolic substances and oil drops. These characteristics suggested the involvement of bulliform cells in the mechanism of foliar involution in the studied species.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Anatomy; Bulliform cells; Cerrado; Poaceae; Ultrastructure.
Ano: 2008 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132008000100014
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Candida albicans morphologies revealed by scanning electron microscopy analysis BJM
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
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Caracterisation des hemocytes d''un mollusque bivalve marin, la nacre, Pinna nobilis L. 1758 ArchiMer
Henry, M; Vicente, N; Houache, N.
The study of tinctorial affinities, in vitro behaviour and ultrastructure of the hemocytes of Pinna nobilis allows us to group them into two main families: basophilic, neutrophilic and acidophilic granulocytes; hyalinocytes, three categories can be distinguished among these cells: small hyalinocytes, hyalinocytes containing smooth endoplasmic reticulum and the macrophage population. The hemocytes participate in the regulation of metabolism by the storage and degradation of glycogen. They contribute to the detoxification process by the sequestration of mineral elements in their lysosomes. Their role in antibacterial defense is suggested by their bacterian phagocytic activity.
Tipo: Text Palavras-chave: Pinna nobilis; Bivalvia; Haemolymph; Animal metabolism; Marine molluscs; Ultrastructure.
Ano: 1991 URL: http://archimer.ifremer.fr/doc/1991/acte-1711.pdf
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Caracteristiques ultrastructurales du spermatozoide de la coquille Saint-Jacques, Pecten maximus (Mollusque, Bivalve) ArchiMer
Dorange, G; Lepennec, M.
The spermatozoon of Pecten maximus is of the primitive type usually associated with species having external fertilization or emitting the sperm in the water. The size of the nucleus is reduced. The middle piece is similar to that reported for several Bivalves. It contains glycogen. But the spermatozoon of P. maximus exhibits its own ultrastructural characteristics: the short acrosome differs in size, shape, position and ultrastructure or by a combination of these from that of many bivalves. No axial rods was observed in contrast to several species of Mytilidae, Veneridae and Ostreidae. These originalities could go to the genus level.
Tipo: Text Palavras-chave: Pecten maximus; Bivalvia; Ultrastructure; Sperm.
Ano: 1991 URL: http://archimer.ifremer.fr/doc/1991/acte-1725.pdf
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Changes in motility, ATP content, morphology and fertilisation capacity during the movement phase of tetraploid Pacific oyster (Crassostrea gigas) sperm ArchiMer
Suquet, Marc; Labbe, C.; Brizard, Raphael; Donval, Anne; Le Coz, Jean-rene; Quere, Claudie; Haffray, P..
Changes in sperm features during the movement phase are especially interesting to study in external fertilization species whose sperm duration movement is long because this implies a significant adaptation of moving cells to the external medium. This study describes the changes in tetraploid Pacific oyster sperm characteristics in relation to time post activation. Sperm individually collected on three tetraploid males were activated in seawater. Their features were analysed over a 24 h period and compared to a sperm pool collected on three diploid males as a reference. The percentage of motile spermatozoa, the intracellular ATP content, and the fine structure of spermatozoa were studied in relation to time post activation. Furthermore, the fertilisation...
Tipo: Text Palavras-chave: Crassostrea gigas; Sperm; Tetraploid; Motility; ATP; Ultrastructure.
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00006/11756/8639.pdf
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Citrus sinensis leaf petiole and blade colonization by Xylella fastidiosa: details of xylem vessel occlusion Scientia Agricola
Alves,Eduardo; Leite,Breno; Pascholati,Sérgio Florentino; Ishida,Maria Lúcia; Andersen,Peter Craig.
Citrus variegated chlorosis (CVC), caused by Xylella fastidiosa, is an important disease of citrus in Brazil. X. fastidiosa is restricted to xylem vessels of plants and knowledge regarding xylem colonization is still limited. Our goal was to verify how this bacterium colonizes and spreads within xylem vessels of sweet orange Citrus sinensis cv. Pêra. Petioles and pieces of leaf blades from naturally infected plant exhibiting characteristic symptoms were prepared for light microscopy (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and immunogold labeling (IGL). Petioles from healthy plants were used as control. IGL results, using an antibody against wall hemicelluloses, revealed that the pit membrane of vessels was altered....
Tipo: Info:eu-repo/semantics/article Palavras-chave: Ultrastructure; Scanning electron microscopy; Transmission electron microscopy; Immunolabel.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162009000200011
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Comparative palynological analysis of Lygodium venustum Sw. and L. volubile Sw. (Lygodiaceae) Anais da ABC (AABC)
GIACOSA,JUAN P. RAMOS; MORBELLI,MARTA A.; GIUDICE,GABRIELA E..
The genus Lygodium Sw. is one of the few climbing ferns in the world. The spores of L. venustum Sw. and L. volubile Sw. were studied using light, scanning, and transmission electron microscopy. This work is based on herbarium material. The spores are trilete, triangular, with straight to convex sides in polar view. The equatorial diameter is 72-104 µm, and the polar diameter is 64-84 µm. The ornamentation in L. venustum is verrucate-tuberculate while in L. volubile, it is verrucate-tuberculate in the proximal face but with a few ridges on the distal face, where a micro-ornamentation constituted by verrrucae and tubercles is observed. An equatorial ridge is also present. The exospore is two-layered; in L. venustum, it is smooth in contrast with the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Lygodiaceae; Lygodium; Morphology; Spores; Ultrastructure.
Ano: 2013 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652013000200699
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