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| Registros recuperados: 5.438 | |
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| Gunski,Ricardo José; Giannoni,Miriam Luz. |
| Sequential banding analysis (Giemsa-C-banding-Ag NOR) of chromosomes of the common rhea (Rhea americana) was performed. Metaphases were obtained by peripheral blood lymphocyte culture and monolayer embryo cell culture. The diploid chromosome number was 80, different from the 2n = 82 in previous reports. Macrochromosome pairs 1, 2 and 5 were submetacentric and pair 3, subacrocentric. The 4th pair was acrocentric and all of the microchromosomes appeared to be acrocentric, with the exception of a clearly metacentric pair which was fully heterochromatic. The Z was slightly larger than the W, both being acrocentric and C-band negative. Nucleolar organizer regions were observed in the secondary constriction of a microchromosome pair. Correct identification of... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000200006 |
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| Beiguelman,Bernardo; Colletto,Gloria M.D.D.; Franchi-Pinto,Carla; Krieger,Henrique. |
| Distributions of birth weights of twins and singletons born at three southeastern Brazilian hospitals were compared after adjustment for gestational age, its quadratic and cubic terms, sex, type of pregnancy, as well as their interactions. The pattern of twin fetal growth rate was retarded in comparison to that of singletons, regardless of the socioeconomic level of the examined population, but the gestational age at which this retardation started seems to be correlated to the income of the mothers. In all cases, after 28 weeks of gestation, female fetal growth was slightly but consistently lower than that of males. |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000100025 |
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| Lange,Claudia E.; Federizzi,Luiz C.; Carvalho,Fernando I.F.; Dornelles,Ana L.C.; Handel,Cristine L.. |
| The genetic bases of in vitro organogenesis and precocious germination of embryos in immature wheat embryo culture were investigated using six Brazilian genotypes and their F1, F2, BC1F1 and BC2F1 generations in a generation means analysis. Four parents and one set of F1s were also analyzed in a diallel experiment. The results indicated a complex gene action controlling both traits, with additive, dominant and epistatic effects. High broad sense heritability values were found, indicating genetic determination. Considering the complexity of gene control, genetic gain could be achieved by selecting for the traits in advanced generations of the segregating population. Low correlation values between organogenesis, precocious germination, regeneration and... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000100015 |
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| Carvalho,Margarida Lima; Oliveira,Claudio; Foresti,Fausto. |
| The present paper reports nuclear DNA content in 30 Neotropical freshwater fish species and summarizes the data on other Neotropical species presented in the literature. Among Neotropical fishes, the nuclear DNA content ranges from 1.04 ± 0.09 pg/nucleus in Corydoras cf. simulatus (2n = 62) to 248.0 pg/nucleus in Lepidosiren paradoxa (2n = 38). A general analysis of the data obtained in the present study for each species showed that DNA measurements were practically constant at the individual level, while significant differences were observed among individuals of the same population. This observation was valid for all species analyzed and was more evident in those species that presented other karyotypic particularities such as sex chromosomes or... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000100009 |
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| Blanco,Rafael; Arcos-Burgos,Mauricio; Paredes,Mónica; Palomino,Hernán; Jara,Lilian; Carreño,Hernán; Obreque,Victor; Muñoz,M.A.. |
| A população urbana Chilena contemporânea deriva da mistura de ameríndios nativos com espanhóis, apresentando uma incidência média de fissura labial não sindrômica associada ou não a fissura palatina (NSCLP) de 1,8 por 1000 nascimentos vivos. A análise de segregação complexa usando o programa de computador POINTER foi feita em 249 pedigrees estendidos, distribuídos em 202 famílias simplex e 47 famílias multiplex obtidas de probands de NSCLP afetados (157 homens e 92 mulheres). Esses pedigrees deram origem a 326 indivíduos afetados e mais de 1454 parentes. Oito modelos hipotéticos foram examinados e comparados pelo teste <FONT FACE="Symbol">c</font> 2 log2 razão de máxima verossimilhança. Os modelos que postulam que NSCLP não era transmitida... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000100023 |
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| Maistro,Edson Luis; Oliveira,Claudio; Foresti,Fausto. |
| Cytogenetic and morphological studies were carried out on nine local populations of Astyanax scabripinnis paranae. All populations exhibited 2n = 50 chromosomes as well as conspicuous differences involving karyotype morphology, number and position of nucleolar organizer regions (NORs) and amount and/or locations of constitutive heterochromatin blocks. A quantitative study of the cytogenetic data showed that eight populations possessed different karyotypes. Morphological analyses based on nine measurements and two meristic parameters were effective in establishing clear identification of five populations. Comparative analysis of cytogenetic and morphological traits suggests that chromosomal changes have occurred at a more rapid rate than morphological... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000200005 |
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| Braga,Gilberto U.L.; Vencovsky,Roland; Messias,Claudio L.. |
| Chitinolytic activity and dry mass production were determined in culture filtrates from 17 Metarhizium anisopliae strains grown in liquid medium containing chitin as the only carbon source. The objectives were to estimate parameters such as genetic variance among strains, heritability and expected gain from selection, as well as correlations between tested traits. Wide genotypic variability was observed among strains in chitinolytic activity, permitting the exploitation of this property in selection. The high heritability suggests that progress can be made through phenotypic selection. The genotypic correlation coefficient between dry mass production and chitinolytic activity detected in the filtrates was negative (<img... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000200001 |
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| Oliveira,Edivaldo H.C. de; Lima,Margarida M.C. de; Sbalqueiro,Ives José; Pissinati,Alcides. |
| The chromosome complements of four males of Alouatta fusca clamitans, caught in Rio de Janeiro State, Brazil, were analyzed by G-, C-, and NOR-banding techniques. The diploid number found was 49 in all the specimens. The presence of a heteromorphic pair of submetacentric chromosomes in the analyzed specimens, not present in males and females with 2n = 50 previously reported, and its G-banding pattern, led us to assume that this pair is involved in a Y-autosome translocation. Thus, the sex determination system appears modified to X1X1X2X2 /X1X2Y. Heterochromatic segments were found in the pericentromeric region of all the chromosomes, in the telomeric region of the short arm in pair 2, in the complete length of the short arm of pairs 5 and 6 and in the... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000300012 |
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| Galli,Leonardo; Viégas,Judith; Augustin,Eliane; Eckert,Marcia Ines; Silva,João Baptista da. |
| Pollen mother cells obtained from regenerated plants of asparagus (Asparagus officinalis L.), in a population composed exclusively of male plants, through the process of anther culture from the hybrid G27 X 22-8, were analyzed during meiosis. It was observed that, during theprocess of anther culture by organogenesis, the pollen mother cells of the regenerants had great genomic instability, as evidenced by disturbances in all the meiotic phases of the first and second division. Furthermore, structural chromosomal abnormalities, in addition to aneuploidy and polyploidy, were observed. |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000100016 |
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| Cuco,Silvia Marina; Bandel,Gerhard. |
| Flowers of three Hevea brasiliensis clones, RRIM 527, RRIM 600 and GT 1, were analyzed under stereomicroscope and scanning electron microscope, aiming to observe hermaphroditism rates. Results showed 71.49% hermaphrodite flowers, 29.83% of which exhibited incompletely developed, residual anthers. The scanning electron microscope analysis did not detect differences in anther epidermis of male and bisexual flowers of RRIM 600 and RRIM 527. In GT 1 clone (sterile male), the anther epidermis was already weak at the beginning of floral development and completely wrinkled at the end of maturation. Consequently, the anthers were empty by this stage. |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000400019 |
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| Colombo,Carlos; Second,Gérard; Valle,Tereza Losada; Charrier,André. |
| RAPD markers were used to investigate the genetic diversity of 31 Brazilian cassava clones. The results were compared with the genetic diversity revealed by botanical descriptors. Both sets of variates revealed identical relationships among the cultivars. Multivariate analysis of genetic similarities placed genotypes destinated for consumption "in nature" in one group, and cultivars useful for flour production in another. Brazils abundance of landraces presents a broad dispersion and is consequently an important resource of genetic variability. The botanical descriptors were not able to differentiate thirteen pairs of cultivars compared two-by-two, while only one was not differentiated by RAPD markers. These results showed the power of RAPD markers over... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000100018 |
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| Acuña,M.; Eaton,L.. |
| In order to investigate the association between ABO blood groups and serum haptoglobin (Hp), we typed Hp and ABO blood groups in 288 children, who were selected at random among those who began their primary school in 1973 in the Northern Metropolitan area of Santiago, Chile. This region has an Amerindian component of 40% and a Caucasian component (principally Spanish) of 60%. Our results are in contrast with previous studies which have reported that Hp*1 varied among ABO groups in the following manner, O < A < B < AB, and where Hp*1 was significantly lower in group O individuals. In the present study, the order was A < O » B < AB. We found more A and less O individuals with allele Hp*2 and genotype Hp 2-2, and more Hp*1... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000400004 |
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| Aquino-Silva,Maria Regina de; Schwantes,Maria Luiza B.; Schwantes,Arno Rudi. |
| A recent locus duplication hypothesis for sMDH-B* was proposed to explain the complex electrophoretic pattern of six bands detected for the soluble form of malate dehydrogenase (MDH, EC 1.1.1.37) in 84% of the Geophagus brasiliensis (Cichlidae, Perciformes) analyzed (AB1B2 individuals). Klebe's serial dilutions were carried out in skeletal muscle extracts. B1 and B2 subunits had the same visual end-points, reflecting a nondivergent pattern for these B-duplicated genes. Since there is no evidence of polyploidy in the Cichlidae family, MDH-B* loci must have evolved from regional gene duplication. Tissue specificities, thermostability and kinetic tests resulted in similar responses from both B-isoforms, in both sMDH phenotypes, suggesting that these more... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000400016 |
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| Junghans,Tatiana Góes; Peters-Robinson,Ingrid; Bertolucci,Fernando L.; Alfenas,Acelino Couto. |
| Self-incompatibility found in a Eucalyptus grandis clone was used to promote interspecific hybridization between E. grandis and E. urophylla clones. The interspecific hybridization achieved in an open-pollinated commercial seed orchard planted in Espírito Santo, Brazil was evaluated by the multi-locus outcrossing rate (tm) of the seed producing clone, E. grandis. The percentage of outcrossed seeds reached 95.9%. The outcrossing rate of individual trees was quite variable, but was always above 70.0%. Wright's coefficient was negative (F = -0.30) revealing an excess of heterozygous genotypes in the progeny. Genetic parameters confirmed the high degree of hybridization expected in this orchard. The 800-m wide protection belt of native tropical forest that... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000300015 |
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| Registros recuperados: 5.438 | |
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