Genetic studies of Psammolestes tertius (Hemiptera : Reduviidae : Triatominae) using male genital morphology, morphometry, isoenzymes, and random amplified polymorphic DNA

Two Brazilian populations of Psammolestes tertius (Ceara and Minas Gerais) collected from thornbird nests (Furnariidae) were compared by male genital morphology, morphametry, isoenzymes, and random amplified polymorphic DNA (RAPD). Merle genitalia showed no difference between the populations. In contrast, morphometry, isoenzyme, and RAPD clearly distinguished the two populations. Possible mechanisms of dispersal and the origin of Psammolestes are discussed.

Genetic and physiological alterations occurring in a yeast population continuously propagated at increasing temperatures with cell recycling

This work investigated the effects of increasing temperature from 30 degrees C to 47 degrees C on the physiological and genetic characteristics of Saccharomyces cerevisiae strain 63M after continuous fermentation with cell recycling in a system of five reactors in series. Steady state was attained at 30 degrees C, and then the temperature of the system was raised so it ranged from 35 degrees C in the last reactor to 43 degrees C in the first reactor or feeding reactor with a 2 degrees C difference between reactors. After 15 days at steady state, the temperature was raised from 37 degrees C to 45 degrees C for 25 days at steady state, then from 39 degrees C to 47 degrees C for 20 days at steady state. Starter strain 63M was a hybrid strain constructed to have a MAT a/alpha, LYS/lys, URA/ura genotype. This hybrid yeast showed vigorous growth on plates at 40 degrees C, weak growth at 41 degrees C, positive assimilation of melibiose, positive fermentation of galactose, raffinose and sucrose. of 156 isolates obtained from this system at the end of the fermentation process, only 17.3% showed the same characteristics as starter strain 63M. Alterations in mating type reaction and in utilization of raffinose, melibiose, and sucrose were identified. Only 1.9% of the isolates lost the ability to grow at 40 degrees C. Isolates showing requirements for lysine and uracil were also obtained. In addition, cell survival was observed at 39-47 degrees C, but no isolates showing growth above 41 degrees C were obtained.

Additive genetic relationship of longevity with fertility and production traits in Nellore cattle based on bivariate models

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genetic susceptibility to bleomycin: A twin study

The frequency of chromatid breaks was analysed in peripheral lymphocytes obtained from sixteen healthy monozygotic (MZ) and sixteen healthy dizygotic (DZ) pairs of twins. In addition, increases in the frequency of chromatid breaks, following in vitro treatment of whole blood with 0.03 unit/ml bleomycin (BLM), were analysed in the same twins. There was a highly significant intrapair difference in the variance of the frequency of chromatid breaks among MZ and DZ twins, before and after BLM treatment. The coefficient of heritability was 85,5% and it was concluded that genetic factors contributed significantly to the individual variation observed in BLM induced chromatid break rates.

Genetic interactions of yeast eukaryotic translation initiation factor 5a (eIF5A) reveal connections to poly(A)-binding protein and protein kinase C signaling

The highly conserved eukaryotic translation initiation factor eIF5A has been proposed to have various roles in the cell, from translation to mRNA decay to nuclear protein export. To further our understanding of this essential protein, three temperature-sensitive alleles of the yeast TIF51A gene have been characterized. Two mutant eIF5A proteins contain mutations in a proline residue at the junction between the two eIFSA domains and the third, strongest allele encodes a protein with a single mutation in each domain, both of which are required for the growth defect. The stronger tif51A alleles cause defects in degradation of short-lived mRNAs, supporting a role for this protein in mRNA decay. A multicopy suppressor screen revealed six genes, the overexpression of which allows growth of a tif51A-1 strain at high temperature; these genes include PAB1, PKC1, and PKC1 regulators WSC1, WSC2, and WSC3. Further results suggest that eIFSA may also be involved in ribosomal synthesis and the WSC/PKC1 signaling pathway for cell wall integrity or related processes.

GSTT1, GSTM1 and CYP2E1 genetic polymorphisms in gastric cancer and chronic gastritis in a Brazilian population

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Internal genetic structure and outcrossing rate in a natural population of Araucaria angustifolia (Bert.) O. Kuntze

The internal genetic structure and outcrossing rate of a population of Araucaria angustifolia (Bert.) O. Kuntze were investigated using 16 allozyme loci. Estimates of the mean number of alleles per loci (1.6), percentage of polymorphic loci (43.8%), and expected genetic diversity (0.170) were similar to those obtained for other gymnosperms. The analysis of spatial autocorrelation demonstrated the presence of internal structure in the first distance classes (up to 70 m), suggesting the presence of family structure. The outcrossing rate was high (0.956), as expected for a dioecious species. However, it was different from unity, indicating outcrossings between related individuals and corroborating the presence of internal genetic structure. The results of this study have implications for the methodologies used in conservation collections and for the use or analysis of this forest species. © The American Genetic Association. 2006. All rights reserved.

DNA repair gene polymorphism is associated with the genetic basis of atherosclerotic coronary artery disease

Background: Atherosclerotic coronary artery disease (CAD) is a multifactorial process that appears to be caused by the interaction of environmental risk factors with multiple predisposing genes. It is nowadays accepted that increased levels of DNA damage induced by xenobiotics play an important role in the early phases of atherogenesis. Therefore, in this study, we focus on determining whether genetic variations in xenobiotic-metabolizing [glutathione-S-transferase theta 1 (GSTT1), glutathione-S-transferase mu 1 (GSTM1), cytochrome P450 IIEI (CYP2E1)] and DNA repair [X-ray cross-complementing group 1 (XRCC1)] genes might be associated with increased risk for CAD. Methods: A case-control study was conducted with 400 individuals who underwent subjected to coronary angiography. A total of 299 were patients diagnosed with effective coronary atherosclerosis (case group; >20% obstructive lesion), and 101 (control group) were individuals diagnosed as negative for CAD (<20% obstructive lesions). The polymorphism identifications for GSTM1 and GSTT1, and for CYP2E1 and XRCC1 genes were performed by polymerase chain reaction (PCR) amplification and by PCR-RFLP, respectively. Results and conclusions: The XRCC1 homozygous wild-type genotype Arg/Arg for codon 399 was statistically less pronounced in the case subjects (21.4%) than in controls (38.5%); individuals with the variant XRCC1 genotype had a 2.3-fold increased risk for coronary atherosclerosis than individuals with the wild-type genotype (OR=2.3, 95% CI=1.13-4.69). Conversely, no association between GSTM1, GSTT1, and CYP2E1gene polymorphisms and coronary atherosclerosis was detected. The results provide evidence of the role of DNA damage and repair in cardiovascular disease. © 2011 Elsevier Inc. All rights reserved.

Multiple-trait random regression models for the estimation of genetic parameters for milk, fat, and protein yield in buffaloes

In this study, genetic parameters for test-day milk, fat, and protein yield were estimated for the first lactation. The data analyzed consisted of 1,433 first lactations of Murrah buffaloes, daughters of 113 sires from 12 herds in the state of São Paulo, Brazil, with calvings from 1985 to 2007. Ten-month classes of lactation days were considered for the test-day yields. The (co)variance components for the 3 traits were estimated using the regression analyses by Bayesian inference applying an animal model by Gibbs sampling. The contemporary groups were defined as herd-year-month of the test day. In the model, the random effects were additive genetic, permanent environment, and residual. The fixed effects were contemporary group and number of milkings (1 or 2), the linear and quadratic effects of the covariable age of the buffalo at calving, as well as the mean lactation curve of the population, which was modeled by orthogonal Legendre polynomials of fourth order. The random effects for the traits studied were modeled by Legendre polynomials of third and fourth order for additive genetic and permanent environment, respectively, the residual variances were modeled considering 4 residual classes. The heritability estimates for the traits were moderate (from 0.21-0.38), with higher estimates in the intermediate lactation phase. The genetic correlation estimates within and among the traits varied from 0.05 to 0.99. The results indicate that the selection for any trait test day will result in an indirect genetic gain for milk, fat, and protein yield in all periods of the lactation curve. The accuracy associated with estimated breeding values obtained using multi-trait random regression was slightly higher (around 8%) compared with single-trait random regression. This difference may be because to the greater amount of information available per animal. © 2013 American Dairy Science Association.

Análise por técnica de RDA (Representational Difference Analysis) da expressão gênica diferencial, para a identificação de fatores genéticos associados à produção de etanol em linhagem de Saccharomyces cerevisae

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Identification and characterization of regions of difference between the Salmonella Gallinarum biovar Gallinarum and the Salmonella Gallinarum biovar Pullorum genomes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Epigenetic and genetic approach to the transmissibility of dental characteristics in twins: report of two cases

Transmissibility of dental and jaw characteristics is strongly influenced by environmental factors during the years of extra uterine life when odontogenesis occurs. Through biochemical factors, such as enzymes, proteins, hormones and other mediators, genes are activated or silenced to suit the cell or organism to its environment. These changes are not transmitted to our descendants, because of that, these factors are called epigenetic. Among the most cited epigenetic factors are food, pollution, drugs and exercise. The objective of this study was to assess the transmissibility of dental characteristics in two pairs of twins. In one case, 13-year-old boys had the same basic dental and jaw characteristics with prolonged retention of the second upper deciduous molars and the presence of permanent successors. In the other case, 14-year-old boys had prolonged retention of lower deciduous second molars and absence of permanent successors, but only one of them had the germs of third lower molars. The phenotypic difference in the dentition of twins from clinical case 2 could be due to epigenetic factors, showing the absence of genetic determinism in the transmissibility of dental characteristics.

Genetic Mapping of Quantitative Trait Loci Associated with Bioenergy Traits, and The Assessment of Genetic Variability in Sweet Sorghum (Sorghum bicolor (L.). Moench)

Sweet sorghum, a botanical variety of sorghum is a potential source of bioenergy because high sugar levels accumulate in its stalks. The objectives of this study were to explore the global diversity of sweet sorghum germplasm, and map the genomic regions that are associated with bioenergy traits. In assessing diversity, 142 sweet sorghum accessions were evaluated with three marker types (SSR, SRAP, and morphological markers) to determine the degree of relatedness among the accessions. The traits measured (anthesis date [AD], plant height [PH], biomass yield [BY], and moisture content [MC]) were all significantly different (P<0.05) among accessions. Morphological marker clustered the accessions into five groups based on PH, MC and AD. The three traits accounted for 92.5% of the variation. There were four and five groups based on SRAP and SSR data respectively classifying accessions mainly on their origin or breeding history. The observed difference between SSR and SRAP based clusters could be attributed to the difference in marker type. SSRs amplify any region of the genome whereas SRAP amplify the open reading frames and promoter regions. Comparing the three marker-type clusters, the markers complimented each other in grouping accessions and would be valuable in assisting breeders to select appropriate lines for crossing. In evaluating QTLs that are associated with bioenergy traits, 165 recombinant inbred lines (RILs) were planted at four environments in Nebraska. A genetic linkage map constructed spanned a length of 1541.3 cM, and generated 18 linkage groups that aligned to the 10 sorghum chromosomes. Fourteen QTLs (6 for brix, 3 for BY, 2 each for AD and MC, and 1 for PH) were mapped. QTLs for the traits that were significantly correlated, colocalized in two clusters on linkage group Sbi01b. Both parents contributed beneficial alleles for most of traits measured, supporting the transgressive segregation in this population. Additional work is needed on exploiting the usefulness of chromosome 1 in breeding sorghum for bioenergy.

Predictive models for mutations in mismatch repair genes: implication for genetic counseling in developing countries

Background: Lynch syndrome (LS) is the most common form of inherited predisposition to colorectal cancer (CRC), accounting for 2-5% of all CRC. LS is an autosomal dominant disease characterized by mutations in the mismatch repair genes mutL homolog 1 (MLH1), mutS homolog 2 (MSH2), postmeiotic segregation increased 1 (PMS1), post-meiotic segregation increased 2 (PMS2) and mutS homolog 6 (MSH6). Mutation risk prediction models can be incorporated into clinical practice, facilitating the decision-making process and identifying individuals for molecular investigation. This is extremely important in countries with limited economic resources. This study aims to evaluate sensitivity and specificity of five predictive models for germline mutations in repair genes in a sample of individuals with suspected Lynch syndrome. Methods: Blood samples from 88 patients were analyzed through sequencing MLH1, MSH2 and MSH6 genes. The probability of detecting a mutation was calculated using the PREMM, Barnetson, MMRpro, Wijnen and Myriad models. To evaluate the sensitivity and specificity of the models, receiver operating characteristic curves were constructed. Results: Of the 88 patients included in this analysis, 31 mutations were identified: 16 were found in the MSH2 gene, 15 in the MLH1 gene and no pathogenic mutations were identified in the MSH6 gene. It was observed that the AUC for the PREMM (0.846), Barnetson (0.850), MMRpro (0.821) and Wijnen (0.807) models did not present significant statistical difference. The Myriad model presented lower AUC (0.704) than the four other models evaluated. Considering thresholds of >= 5%, the models sensitivity varied between 1 (Myriad) and 0.87 (Wijnen) and specificity ranged from 0 (Myriad) to 0.38 (Barnetson). Conclusions: The Barnetson, PREMM, MMRpro and Wijnen models present similar AUC. The AUC of the Myriad model is statistically inferior to the four other models.

Association study between the rs165599 catechol-O-methyltransferase genetic polymorphism and schizophrenia in a Brazilian sample

Schizophrenia is a severe psychiatric disorder with frequent recurrent psychotic relapses and progressive functional impairment. It results from a poorly understood gene-environment interaction. The gene encoding catechol-O-methyltransferase (COMT) is a likely candidate for schizophrenia. Its rs165599 (A/G) polymorphism has been shown to be associated with alteration of COMT gene expression. Therefore, the present study aimed to investigate a possible association between schizophrenia and this polymorphism. The distribution of the alleles and genotypes of this polymorphism was investigated in a Brazilian sample of 245 patients and 834 controls. The genotypic frequencies were in Hardy-Weinberg equilibrium and no statistically significant differences were found between cases and controls when analyzed according to gender or schizophrenia subtypes. There was also no difference in homozygosis between cases and controls. Thus, in the sample studied, there was no evidence of any association between schizophrenia and rs165599 (A/G) polymorphism in the non-coding region 3' of the COMT gene.