Quantitative genetic study of age at subsequent rebreeding in Nellore cattle by using survival analysis

The continuous trait age at subsequent rebreeding (ASR) was evaluated using survival analysis in Nellore breed cows that conceived for the first time at approximately 14 months of age. This methodology was chosen because the restricted breeding season produces censored data. The dataset contained 2885 records of ASR (in days). Records of females that did not produce calves in the following year after being exposed to a sire were considered censored (48.3% of the total). The statistical model used was a Weibull mixed survival model, which included fixed effects of contemporary groups (CG) and period and a random effect of individual animal. The effect of contemporary groups on ASR was significant (P < 0.01). Heritabilities obtained for ASR were 0.03 and 0.04 in logarithmic and original scales, respectively. These results indicate that the genetic selection response for subsequent reproduction of 2-year-old Nellore breed females is not expected to be effective based on survival analysis. Furthermore, these results suggest that environmental improvement is fundamental to this important trait. It should be highlighted that an increase in the average date of birth can produce an adverse effect in the future, since this cannot be compensated by genetic improvement.

Genetic analysis on growth and carcass traits in Nelore cattle

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Non invasive methods for genetic analysis applied to ecological and behavioral studies in Latino-America

Documenting the presence and abundance of the neotropical mammals is the first step for understanding their population ecology, behavior and genetic dynamics in designing conservation plans. The combination of field research with molecular genetics techniques are new tools that provide valuable biological information avoiding the disturbance in the ecosystems, trying to minimize the human impact in the process to gather biological information. The objective of this paper is to review the available non invasive sampling techniques that have been used in Neotropical mammal studies to apply to determine the presence and abundance, population structure, sex ratio, taxonomic diagnostic using mitochondrial markers, and assessing genetic variability using nuclear markers. There are a wide range of non invasive sampling techniques used to determine the species identification that inhabit an area such as searching for tracks, feces, and carcasses. Other useful equipment is the camera traps that can generate an image bank that can be valuable to assess species presence and abundance by morphology. With recent advances in molecular biology, it is now possible to use the trace amounts of DNA in feces and amplify it to analyze the species diversity in an area, and the genetic variability at intraspecific level. This is particularly helpful in cases of sympatric and cryptic species in which morphology failed to diagnose the taxonomic status of several species of brocket deer of the genus Mazama.

Genetic analysis of visual scores and their relationships to mature female weight in Nellore breed

Dados de 79.884 animais da raça Nelore foram utilizados para estimar parâmetros genéticos e avaliar as relações entre os escores de conformação, precocidade e musculatura obtidos à desmama e ao sobreano e o peso das fêmeas à idade adulta. Utilizou-se o método da máxima verossimilhança restrita, em análise multicaracterísticas, com modelo que incluiu os efeitos genéticos aditivos direto e residual, como aleatórios, e os efeitos fixos de grupo de contemporâneos e, como covariáveis, a idade do animal à pesagem e a idade da mãe ao parto (exceto para o peso das fêmeas à idade adulta). Os grupos contemporâneos à desmama foram definidos pelas variáveis: sexo, rebanho, ano e mês de nascimento, grupo de manejo ao nascimento e à desmama. Na definição de grupo contemporâneo ao sobreano também foi incluída a variável grupo de manejo ao sobreano. Para o peso das fêmeas à idade adulta, o grupo de contemporâneos foi composto por rebanho, ano de nascimento, grupo de manejo ao sobreano, ano e estação da pesagem. Os efeitos genético materno e de ambiente permanente materno também foram incluídos no modelo para análise dos escores de conformação, precocidade e musculatura à desmama. As estimativas de herdabilidade direta obtidas foram 0,18 ± 0,02 para o escore de conformação; 0,21 ± 0,01 para o escore de precocidade; 0,22 ± 0,01 para o escore de musculatura à desmama e 0,24 ± 0,01 para o escore de conformação; 0,27 ± 0,01 para o escore de precocidade; e 0,26 ± 0,01 para o escore de musculatura ao sobreano e 0,42 ± 0,02 para o peso das fêmeas à idade adulta. As correlações genéticas estimadas entre os escores visuais medidos à desmama e ao sobreano foram positivas, variando de média a alta magnitude (0,56 ± 0,03 a 0,85 ± 0,01). Por outro lado, as correlações genéticas estimadas entre os escores visuais e o peso das fêmeas à idade adulta foram positivas e moderadas, variando de 0,21 ± 0,03 a 0,35 ± 0,03. Os resultados obtidos indicam que a seleção de animais com maiores escores visuais, principalmente ao sobreano, deve promover aumento do peso das fêmeas à idade adulta.

Spot-test identification and rapid quantitative sequential analysis of dipyrone

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

Genetic analysis of phosphoprotein and matrix protein of rabies viruses isolated in Brazil

To investigate the genetic characteristics of phosphoprotein (P) and matrix protein (M) genes of variable rabies virus (RV) prevalent in Brazil, the authors genetically characterized the P and M genes from 30 Brazilian RV field isolates. Phylogenetic analysis based on the P and M genes revealed the presence of six RV variants that consisted primarily of three insectivorous bats, the vampire bat, dog and fox in Brazil. Specific amino acid substitutions corresponding to these phylogenetic lineages were observed, with ASP(42) and GlU(62) in the P protein found to be characteristic of Brazilian chiroptera- and carnivora-related RVs, respectively. Amino acid sequence motifs predicted to associate with a viral function in the P and M proteins were conserved among Brazilian RV variants.

Quantitative structural analysis of the transition from LT-LixCoO2 to HT-LixCoO2 using the rietveld method: correlation between structure and electrochemical performance

A quantitative phase analysis was made of LiXCoO2 powders obtained by two distinct chemical methodologies at different temperatures (from 400 to 700degreesC). A phase analysis was made using Rietveld refinements based on X-ray diffraction data, considering the LiXCoO2 powders as a multiphase system that simultaneously contained two main phases with distinct, layered and spinel-type structures. The sults showed the coexistence of both structures in LiXCoO2 obtained at low temperature (400 and 500degreesC), although only the layered structure was detected at higher temperatures (600 and 700degreesC, regardless of the chemical powder process employed. The electrochemical performance, evaluated mainly by the cycling reversibility of LiXCoO2 in the form of cathode insertion electrodes, revealed that there is a close correlation between structural features and the electrochemical response, with one of the redox processes (3.3 v/3.9 v) associated only with the presence of the spinel-type structure. (C) 2003 Elsevier B.V. All rights reserved.

Clinical features and genetic analysis of four Brazilian kindreds with resistance to thyroid hormone

Objective Resistance to thyroid hormone (RTH) is a dominantly inherited syndrome of reduced tissue responsiveness to thyroid hormone usually due to mutations located in the ligand-binding domain and adjacent hinge region of the thyroid hormone receptor beta (TR beta). In the present report we describe the clinical and laboratory characteristics and the genetic analysis of patients with this rare disorder from a Brazilian population.Patients Four unrelated Brazilian families with diagnosis of RTH were studied. Age at diagnosis varied from 14 months to 29 years.Results All affected individuals were clinically euthyroid, except for one patient who presented immediately after birth with hyperthyroidism. All individuals had tachycardia and goitre, elevated concentrations of free thyroid hormones and reduced sensitivity to thyroid hormone. Direct sequencing analysis of the TR beta gene revealed four previously reported mutations: c.949G -> A, c.1313G -> A, c.1357C -> A and c.1358dupC in families A, B, C and D, respectively.Conclusion the present report shows that the frequent mutations described in the thyroid hormone receptor worldwide are also present in the Brazilian population, which is characterized by a variable ethnic background.

Quantitative structural analysis of the transition from LT-Li xCoO2 to HT-LixCoO2 using the rietveld method: Correlation between structure and electrochemical performance

A quantitative phase analysis was made of LixCoO2 powders obtained by two distinct chemical methodologies at different temperatures (from 400 to 700°C). A phase analysis was made using Rietveld refinements based on X-ray diffraction data, considering the Li xCoO2 powders as a multiphase system that simultaneously contained two main phases with distinct, layered and spinel-type structures. The results showed the coexistence of both structures in LixCoO 2 obtained at low temperature (400 and 500°C), although only the layered structure was detected at higher temperatures (600 and 700°C), regardless of the chemical powder process employed. The electrochemical performance, evaluated mainly by the cycling reversibility of Li xCoO2 in the form of cathode insertion electrodes, revealed that there is a close correlation between structural features and the electrochemical response, with one of the redox processes (3.3 v/3.9 v) associated only with the presence of the spinel-type structure. © 2003 Elsevier B.V. All rights reserved.

Quantitative HPLC analysis of sesquiterpene lactones and determination of chemotypes in Eremanthus seidelii MacLeish & Schumacher (Asteraceae)

Eremanthus seidelii MacLeish & Schumacher has a restricted occurrence to the Brazilian cerrado surrounding the Furnas (MG) reservoir, in environments that have been seriously damaged by human activity. The present phytochemical investigation reveals that the sesquiterpene lactones (SL) 4β,5-dihydro-2′,3′-dihydroxy-15-desoxy-goyazensolide (1) and 4β,5-dihydro-1′,2′-epoxy-eremantholide-C (2) are the major secondary metabolites in E. seidelii leaves, and an HPLC method was developed for their quantitative analysis. HPLC analysis showed no significant seasonal variation in the concentrations of both SL. No qualitative differences were found in the SL patterns of all individuals sampled. However, there is a different SL quantitative pattern among the plants analyzed, pointing to the existence of three quantitative chemotypes of this species, with differences possibly originating from the activity of the enzymes that cyclize the goyazensolide type SL (1) to a eremantholide type SL (2). ©2005 Sociedade Brasileira de Química.

Transferability and use of microsatellite markers for the genetic analysis of the germplasm of some Arachis section species of the genus Arachis

The Arachis section is the most important of the nine sections of the genus Arachis because it includes the cultivated peanut, Arachis hypogaea. The genetic improvement of A. hypogaea using wild relatives is at an early stage of development in spite of their potential as sources of genes, including those for disease and pests resistance, that are not found in the A. hypogaea primary gene pool. Section Arachis species germplasm has been collected and maintained in gene banks and its use and effective conservation depends on our knowledge of the genetic variability contained in this material. Microsatellites are routinely used for the analysis of genetic variability because they are highly polymorphic and codominant. The objective of this study was to evaluate the transferability of microsatellite primers and the assay of genetic variability between and within the germplasm of some species of the Arachis section. Fourteen microsatellite loci developed for three different species of Arachis were analyzed and 11 (78%) were found to be polymorphic. All loci had transferability to all the species analyzed. The polymorphic loci were very informative, with expected heterozygosity per locus ranging from 0.70 to 0.94. In general, the germplasm analyzed showed wide genetic variation. © 2006 Sociedade Brasileira de Genética.