SABIIA - Sistema Aberto e Integrado de Informação em Agricultura (Sabiia)

Leal,Tereza Cristina A.; Leal,Nilma C.; Almeida,Alzira M. Paiva de.

Sixteen strains of Yersinia enterocolitica serotype O:3, isolated from apparently healthy pigs collected in Rio de Janeiro, and four human strains of serotypes O:4, O:5, O:6 and O:13 were analyzed by RAPD-PCR. The strains were grouped into five genotypic profiles according to the amplification patterns obtained with three random primers. Fifteen of the 16 pig strains had identical amplification patterns, which was named genotypic profile 1. The one different profile was named genotypic profile 2. Genotypic profile 1 was also exhibited by the O:6 human serotype strain. The O:4 and O:13 human serotype strains showed similar amplification profiles with two primers. However, the third primer induced a distinct profile in each strain. Therefore, these two...

Cell fusion and chromatin degeneration in an inbred line of maize

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000300005

Caetano-Pereira,Creuci Maria; Pagliarini,Maria Suely; Brasil,Edward Madureira.

A large number of maize genotypes are currently being evaluated to determine the effect of environmental stress caused by the aluminum found in cerrado soils on meiotic behavior. In the present study we report the occurrence of cell fusion followed or not by chromatin degeneration in meiocytes of some plants of an inbred line of maize grown on acid and corrected soil in the Brazilian central plateau. The results suggest the absence of any soil effect on the irregularities observed since the number of affected plants was higher among those grown on corrected soil. The possible causes of these irregularities and their influence on male sterility are discussed.

Identification of resistant genotypes considering polygenic systems in host-pathogen interaction

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000100014

Melo,Leonardo Cunha; Santos,João Bosco dos.

Plant resistance to pathogens is the most efficient form of disease control. However, identification of resistant genotypes is often difficult, especially when the genetic basis for the host-pathogen relationship is unknown. This study was carried out to test a methodology capable of providing, in a simple way, information about host vertical and horizontal resistance as well as pathogen virulence. A simulation using twenty, ten, and five pathogen races and twenty hosts was carried out. Host reaction was controlled by ten genes with two alleles each. Eight genes had little effects, one had medium and the other strong effects. Genetic control of pathogenicity was identical to that of the host. Only homozygous genotypes were used for pathogens and hosts in...

Genetic variability in five species of Anostomidae (Ostariophysi - Characiformes)

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000400022

Chiari,Lucimara; Sodré,Leda Maria Koelblinger.

Genetic variability was studied in five fish species (Anostomidae): Schizodon intermedius and S. nasutus and Leporinus friderici, L. elongatus and L. obtusidens, collected at one location on the Tibagi River (Paraná, Brazil). The protein data from seven systems coded collectively for 19 loci in the liver, muscle and heart. Nine of these loci were polymorphic. The estimated proportion of polymorphism loci (<img src="http:/img/fbpe/gmb/v22n4/si_p_.gif" align="absmiddle">) varied from 16.7% in S. intermedius to 36.9% in L. friderici; the mean heterozygosity observed (<img src="http:/img/fbpe/gmb/v22n4/si_h_.gif" alt="si_h_.gif (76 bytes)" align="absmiddle">o) was 0.027 ± 0.015 and 0.109 ± 0.042, respectively. The estimated value of the genetic...

Genetic control of common bean (Phaseolus vulgaris) resistance to powdery mildew (Erysiphe polygoni)

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000400009

Rezende,Viviane Ferreira; Ramalho,Magno Antonio Patto; Corte,Hercules Renato.

Genetic control of common bean (Phaseolus vulgaris) resistance to powdery mildew (Erysiphe polygoni) was studied using segregating populations from the bean variety crosses Jalo x ESAL 686 and ESAL 550 x ESAL 686. F2 plants, together with the parents, were inoculated and evaluated using a scale of values from one (plant without symptoms) to nine (completely infected plant). F2 plants were harvested individually, and F2:3 families were obtained. These families were evaluated in an 11 x 11 and 12 x 12 simple lattice statistical design for the Jalo x ESAL 686 and ESAL 550 x ESAL 686 crosses, respectively, using the same value scale as the F2 generation. The segregation observed in F2 plants and F2:3 families indicated that two genes are involved in genetic...

Cytogenetic studies of two freshwater sciaenids of the genus Plagioscion (Perciformes, Sciaenidae) from the central Amazon

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000200017

Feldberg,Eliana; Porto,Jorge Ivan Rebelo; Santos,Elen Bethlen Pedraça dos; Valentim,Francisco Carlos Souza.

Cytogenetic characterization of two freshwater sciaenid species from the genus Plagioscion (P. squamosissimus and Plagioscion sp.) was obtained for the first time. Giemsa staining, Ag-NOR and C-banding revealed that both species presented 2n = 48 chromosomes (almost all acrocentric). Single NORs and heterochromatin were found mainly at the pericentromeric position. Karyotypic formulae and NOR location proved to be valuable in showing both interspecific and intraspecific differences. All chromosomes were acrocentric in P. squamosissimus. NORs were located at proximal positions on the long arms of the last chromosome pair of the complement, and were heteromorphic due to size differences. Such heteromorphic NORs seem to be associated with each population...

Intrapopulational genetic differentiation in Anopheles (N.) darlingi Root, 1926 (Diptera: Culicidae) in the amazon region

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000300011

Santos,Joselita Maria Mendes dos; Lobo,Jorge Arturo; Tadei,Wanderli Pedro; Contel,Eucleia P. Betioli.

Four natural Amazonian Anopheles darlingi populations were analyzed for 19 loci, 12 of which showed variation, i.e., 68.4% of polymorphic loci. The Ariquemes, Rondônia, population was the most variable, with a large number of alleles per locus (2.26 ± 0.27) and high polymorphism (P = 63.15). The highest values of observed and expected intralocus heterozygosity were observed in the Manaus, Amazonas, population (Ho = 0.432 ± 0.11; He = 0.375 ± 0.08), and the lowest in the Cachoeira Porteira, Pará, population (Ho = 0.236 ± 0.09; He = 0.290 ± 0.11). Wright's F-statistic revealed disequilibrium caused by an excess of homozygotes, as shown by the Fis > Fst values (Fis = 0.083 > 0.026) reflecting intrapopulational differentiation. The four...

Karyological study of cicindelidia trifasciata (coleoptera, cicindelidae) from cuba: evidence of B chromosomes

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000300007

Proença,Sónia J.R.; Collares-Pereira,M.J.; Serrano,A.R.M..

Metaphases from germinal tissue of eight males and seven females of Cicindelidia trifasciata from Cuba were analyzed. The species karyotype does not fit the pattern described for Nearctic cicindelids (2n = 18 + XXY): it has 11 autosome pairs and a sex chromosome system of the X1X2X3Y/ X1X1X2X2 X3X3 type, thus a diploid value of 2n = 26 in males and 2n = 28 in females. The first two autosome pairs were almost twice as large as the remaining chromosomes, and the sex elements were morphologically well differentiated. This population was found to be polymorphic for supernumerary chromosomes at both the intraindividual and interindividual levels. An extra small B chromosome was observed in all metaphases of one male (2n = 27), and every female showed metaphases...

Genetic counseling follow-up - a retrospective study with a quantitative approach

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000100010

De Pina-Neto,João M.; Petean,Eucia Beatriz L..

The impact of genetic counseling (GC) was evaluated in families, who were interviewed at least two and half years and at most seven years after GC at the Genetics Service of the University Hospital, Faculty of Medicine of Ribeirão Preto, University of São Paulo (HC, FMRP, USP). The 113 families interviewed in this study were asked 48 questions and all children born after GC were studied clinically. We evaluated the families for spontaneous motivation for GC and understanding of GC information, their reproductive decisions, changes in the family after GC and the health status of new children. The majority of families seen at the Hospital das Clínicas de Ribeirão Preto were not spontaneously motivated to undergo GC. They had a low level of understanding...

Did Sutton and Boveri propose the so-called Sutton-Boveri chromosome hypothesis?

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000300003

Martins,L.A.-C.P..

The "Sutton-Boveri chromosome hypothesis" attempted to establish a parallel between cytological chromosome behavior and the principles followed by Mendelian factors. Today, this hypothesis is well accepted; however, it was not completely accepted at its proposal (1902-3). The aim of the present study is to elucidate the meaning of the chromosome hypothesis based on the original scientific works, taking into account the scientific context of that time. The negative treatment this hypothesis received is evaluated. I conclude that it was unfair to include Boveri's name beside that of Sutton's as one of the proponents of the chromosome hypothesis of Mendelian heredity, because he did not publish any hypothesis of that kind during the relevant period...

Numerical chromosome polymorphism in Mikania cordifolia Willd. (Asteraceae)

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000200022

Maffei,E.M.D.; Marin-Morales,M.A.; Ruas,P.M.; Ruas,C.F..

Cytogenetical analysis of Mikania cordifolia, from southeastern Brazil, using the conventional Feulgen method, showed a chromosome number of 2n = 36. Previous karyotypic descriptions for this species showed a numerical chromosome variation of 2n = 34 to 38. There was a secondary constriction in every metaphase in the first chromosome pair, which constitutes a cytological marker. Small extranumerary chromosomes with numerical variation in the same plant were found in the tenth chromosome pair.

Genetic parameters of test day milk yields of Holstein cows

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000400023

Machado,S.G.; Freitas,M.A.R.; Gadini,C.H..

Data were obtained from 17,968 records from 2,130 first lactations of Holstein cows calving between 1988 and 1991. The subjects were daughters of 136 sires monitored by Brazilian Breeders Association, Animal Science Institute, Department of Agriculture, a branch of the State of São Paulo. Data were divided into 10 subsets based on the number of days in milk yield. Test day milk yields (M1 to M10) and 305-day milk yield (M305) were the traits studied. These traits were adjusted for several environmental effects: class of cow age at calving, interval from calving to first test day, and herd-year-season. Restricted maximum likelihood estimates of (co)variance components were obtained from one and two-traits analysis under a sire model. Estimates of...

Morphological dimorphism in the Y chromosome of "pé-duro" cattle in the Brazilian State of Piauí

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000300016

Britto,Carmen M.C.; Mello,Maria Luiza S..

"Pé-duro" (hard foot) is a rare breed of beef cattle of European (Bos taurus taurus) origin, originated in northern and northeastern Brazil. Y chromosome morphology, outer genital elements and other phenotypic characteristics were examined in 75 "pé-duro" bulls from the Empresa Brasileira de Pesquisa Agropecuária (Embrapa) herd in the Brazilian State of Piauí. The purpose was to investigate possible racial contamination with Zebu animals (Bos taurus indicus) in a cattle that has been considered closest to its European origin (B. t. taurus). The presence of both submetacentric and acrocentric Y chromosomes, typical of B. t. taurus and B. t. indicus, respectively, and the larger preputial sheath in bulls with an acrocentric Y chromosome indicated racial...

Clonal chromosome abnormalites found in three non-neoplastic proliferative brain lesions

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000300014

Rainho,Cláudia Aparecida; Barbieri Neto,José; Moraes,Lamartine Correa de; Rogatto,Silvia Regina.

Chromosome analysis was made of brain lesions from three patients which, according to classical histopathological criteria, did not contain tumor cells. In addition to normal cells, we identified abnormal karyotypes with clonal numerical and structural chromosome alterations in at least two independently originated primary cultures from each lesion. Our data suggest that chromosomal aberrations can exist in vivo in non-neoplastic lesions. Other abnormalities may be due to genetic instability manifested only in vitro (culture artifacts) or may already have been present in brain tissue, reflecting previous chromosome damage (as a result of exposure to chemical treatment or enviromental clastogens).

Theory and analysis of partial diallel crosses

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000100006

Viana,José Marcelo Soriano; Cruz,Cosme Damião; Cardoso,Antonio Américo.

This study presents theory and analysis of partial diallel crosses based on Hayman's methods. This genetic design consists of crosses among two parental groups. It should be used when there are two groups of parents, for example, dent and flint maize inbred lines, and the breeder is not interested in the assessment of crosses between parents of the same group. Analyses are carried out using data from the parents and their F1 hybrids allowing a detailed characterization of the polygenic systems under study and the choice of parents for hybridization. Diallel analysis allows the estimation of genetic and non-genetic components of variation and genetic parameters and to assess the following: genetic variability in each group; genotypic differences between...

Transformation of the entomopathogenic fungi, paecilomyces fumosoroseus and paecilomyces lilacinus (deuteromycotina: hyphomycetes) to benomyl resistence

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000400021

Inglis,Peter W.; Tigano,Myrian S.; Valadares-Inglis,M. Cléria.

The entomopathogenic fungi Paecilomyces fumosoroseus and P. lilacinus have been transformed to resistance to the fungicide benomyl by a polyethylene glycol (PEG)-mediated procedure using a mutant b-tubulin gene from Neurospora crassa carried on plasmid pBT6. Benomyl-resistant transformants of P. lilacinus were obtained that could tolerate greater than 30 µg/ml benomyl and P. fumosoroseus transformants were obtained that could tolerate 20 µg/ml benomyl. Following 5 serial passages of transformants on benomyl-containing media and 5 serial passages on non-selective media, 100% of P. lilacinus transformants were found to be mitotically stable by a conidial germination test. In contrast, only 4 out of 9 transformants of P....

k-Casein, b-lactoglobulin and growth hormone allele frequencies and genetic distances in Nelore, Gyr, Guzerá, Caracu, Charolais, Canchim and Santa Gertrudis cattle

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000100023

Kemenes,Paola Augusta; Regitano,Luciana Correia de Almeida; Rosa,Artur Jordão de Magalhães; Packer,Irineu Umberto; Razook,Alexander George; Figueiredo,Leopoldo Andrade de; Silva,Nirlei Aparecida; Etchegaray,Maria Antônia L.; Coutinho,Luiz Lehmann.

The genotypes for k-casein (k-CN), b-lactoglobulin (b-LG) and growth hormone (GH) were determined by polymerase chain reaction (PCR) and restriction enzyme digestion in seven breeds of cattle (Nelore, Gyr, Guzerá, Caracu, Charolais, Canchim and Santa Gertrudis). k-Casein had two alleles with the A allele occurring at a higher frequency in Bos indicus breeds (0.93, 0.92 and 0.91% for Gyr, Guzerá and Nelore, respectively). The b-lactoglobulin locus had two alleles in all of the breeds. European breeds had a higher frequency of the <FONT...

E6, a dominant gene conditioning early flowering and maturity in soybeans

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000400012

Bonato,Emídio Rizzo; Vello,Natal Antonio.

Inheritance was studied in natural variants of the soybean cultivar Paraná, developed under photoperiodic conditions ranging from 13 h 31 min day light, at sowing, to 14 h 23 min, 59 days afterwards. Results indicated that early flowering and maturity are controlled by a single dominant gene. Natural mutations that originated cultivars Paranagoiana and SS-1 occurred at the same locus of cultivar Paraná. It was not possible to determine if the recessive alleles of these mutant cultivars are different. The designation E6 was proposed for the alleles determining earliness in cultivar Paraná, and e6 for the gene determining late flowering and maturity in cultivars Paranagoiana and SS-1, until the individuality of the alleles of Paranagoiana and SS-1 is...

Olive oil protects against chromosomal aberrations induced by doxorubicin in wistar rat bone marrow cells

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000200016

Antunes,Lusânia Maria Greggi; Takahashi,Catarina Satie.

There is considerable interest in identifying dietary compounds which have the capacity to protect against chromosomal aberrations induced by antitumor agents. Fatty acids and their constituents are able to act as free radical scavengers. Doxorubicin (DXR) is an important chemotherapeutic agent, that also induces chromosome aberrations. Rat bone marrow cells treated simultaneously with olive oil (10 ml/kg body weight) and DXR (90 mg/kg body weight) developed significantly fewer chromosomal aberrations and abnormal metaphases than those treated with DXR alone.

Codominant inheritance of polymorphic color variants of Gracilaria domingensis (Gracilariales, Rhodophyta)

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000200015

Plastino,Estela M.; Guimarães,Melina; Matioli,Sergio R.; Oliveira,Eurico C..

Agar is the most valuable phycocoloid in the world market. Currently, about half of its production is obtained from the red alga Gracilaria (Gracilariales, Rhodophyta). Consequently, this genus has been the subject of many studies worldwide. A common green color variant of G. domingensis (Kützing) Sonder ex Dickie was found in a natural population on the northeastern coast of Brazil. Crosses were performed to determine the mode of color inheritance. The results can be interpreted as the expression of a pair of codominant alleles, where the green and red phenotypes are homozygous, and the heterozygotes present a brownish color. Heterozygous tetrasporophytes, at least until they are 4-5 cm long, exhibit a parental influence on the female gametophyte, since...