Conformação de úbere de caprinos da raça saanen: parâmetros estéticos ou funcionais? / Udder conformation of saanen goats: aesthetic or functional parameters?

Diversos fatores predisponentes são descritos para as afecções mamárias ou distúrbios secundários que comprometem a qualidade e produtividade de leite de fêmeas nas diferentes espécies. As características fenotípicas do úbere são consideradas na avaliação econômica de uma fêmea caprina, tanto pelo potencial de produção como pelo registro genealógico dessa fêmea. A limitação de estudos correlacionando essas características com a saúde do úbere gera a dúvida a respeito do significado da conformação do mesmo à saúde e produtividade da glândula mamária. Sendo assim, este estudo teve como objetivo relacionar os parâmetros da conformação do úbere com a celularidade da glândula mamária aferida pelo teste California Mastitis Test (CMT) e contagem de células somáticas (CCS) em 80 cabras da raça Saanen sem alterações no exame clínico da glândula mamária nem no teste de Tamis. Observou-se que a maioria dos parâmetros fenotípicos de úbere não influenciou a CCS, sendo considerados puramente estéticos. A circunferência e profundidade de úbere demonstraram correlação negativa com a celularidade e, por serem características de herdabilidade moderada a alta, podem ser parâmetros considerados para seleção genética de caprinos.

Several predisposing factors are described for mammary diseases or secondary disorders that compromise the quality and productivity of milk from females in different species. The phenotypic characteristics of the udder are considered in the economic evaluation of a female goat, whether for production potential, or as the genealogical record for these females. The limitation of studies correlating these features with the udder health raises doubt about the meaning of the conformation to the health and productivity of the mammary gland. Therefore, this study aimed to list the parameters of the udder conformation with the cellularity of the mammary gland checked by California Mastitis Test (CMT) and somatic cell count (SCC) in 80 Saanen goats without alterations in the clinical examination of the mammary gland or the Tamis test. It was observed that most of the phenotypic parameters of the udder did not influence the CCS, being considered purely esthetic. The circumference and udder depth showed negative correlation with the cellularity and moderate to high heritability traits can be considered parameters for genetic selection of goats.

Ab initio 3-D structure prediction of an artificially designed three-alpha-helix bundle via all-atom molecular dynamics simulations

The rate at which knowledge about genomic sequences and their protein products is produced is increasing much faster than the rate of 3-dimensional protein structure determination by experimental methods, such as X-ray diffraction and nuclear magnetic resonance. One of the major challenges in structural bioinformatics is the conversion of genomic sequences into useful information, such as characterization of protein structure and function. Using molecular dynamics (MD) simulations, we predicted the 3-dimensional structure of an artificially designed three-alpha-helix bundle, called A3, from a fully extended initial conformation, based on its amino acid sequence. The MD protocol enabled us to obtain the secondary, in 1.0 ns, as well as the supersecondary and tertiary structures, in 4.0-10.0 ns, of A3, much faster than previously described for a similar protein system. The structure obtained at the end of the 10.0-ns MD simulation was topologically a three-alpha-helix bundle.

A role for histone-like protein H1 (H-NS) in the regulation of hemolysin expression by Serratia marcescens

The histone-like protein H1 (H-NS) is an abundant structural component of the bacterial nucleoid and influences many cellular processes including recombination, transcription and transposition. Mutations in the hns gene encoding H-NS are highly pleiotropic, affecting the expression of many unrelated genes. We have studied the role of H-NS on the regulation of hemolysin gene expression in Serratia marcescens. The Escherichia coli hns mutant carrying S. marcescens hemolysin genes on a plasmid constructed by ligation of the 3.2-kb HindIII-SacI fragment of pR02 into pBluescriptIIKS, showed a high level of expression of this hemolytic factor. To determine the osmoregulation of wild-type and hns defective mutants the cells were grown to mid-logarithmic phase in LB medium with 0.06 or 0.3 M NaCl containing ampicillin and kanamycin, whereas to analyze the effect of pH on hemolysin expression, the cells were grown to late-logarithmic phase in LB medium buffered with 0.1 M Tris-HCl, pH 4.5 to 8.0. To assay growth phase-related hemolysin production, bacterial cells were grown in LB medium supplemented with ampicillin and kanamycin. The expression of S. marcescens hemolysin genes in wild-type E. coli and in an hns-defective derivative at different pH and during different growth phases indicated that, in the absence of H-NS, the expression of hemolysin did not vary with pH changes or growth phases. Furthermore, the data suggest that H-NS may play an important role in the regulation of hemolysin expression in S. marcescens and its effect may be due to changes in DNA topology influencing transcription and thus the amount of hemolysin expression. Implications for the mechanism by which H-NS influences gene expression are discussed.

Steroid-induced cataracts in patients with autoinmune hepatitis

BACKGROUND: Posterior subcapsular cataract (PSC) has been reported in patients on corticosteroids therapy for various pathologies. Autoimmune hepatitis (AIH) is a progressive inflammatory hepatic disease for which corticosteroids are recommended but PSC has not yet been reported in AIH patients on corticosteroids therapy. METHODS: The AIH patients at our service underwent an ophthalmological assessment and their files were analyzed establish the dosage and duration of medication, the presence of visual complaints and the type of AIH, in order to correlate these with the ophthalmological findings. Patients were examined with a slit lamp following pupil dilation. RESULTS: 17 AIH patients evaluated, only one patient had PSC. CONCLUSION: Although the frequency of PSC was low (1/17) in AIH patients on costicosteroid therapy, these individuals should undergo occasional ophthalmological assessment for the presence of cataracts since their visual acuity and quality of life may be adversely affected.

Plasmid coding for aerobactin production and drug resistance is involved in virulence of Escherichia coli avian strains

Strain of avian septicemic E. coli were examined for association among the determinants of drug resistance, the genes for aerobactin production and virulence. In conjugation experiments, a single plasmid (100 Md) from a strain of septicemic E. coli (UEL 29) transferred to E. coli K12 pathogenicity for 1-day old chicks plus resistance to streptomycin and the ability to produce aerobactin and colicin. Additional evidence for the association of R-plasmid and the production of aerobactin, colicin, resistance to sulfadiazine and pathogenicity was obtained by disassociation when all traits were lost simultaneously. These data provide additional evidence for the importance of the aerobactin system for the pathogenicity of avian E. coli

Construction of a gene library from Azospirillum brasilense and characterization of a recombinant containing the nif structural genes

1.We have constructed a gene library, from Azospirillum brasilense using the vector EMBL4. 2. A recombinant containing the nif structural genes from A. brasilense was isolated and characterized. This recombinant contains a DNA insert of about 15 kilobases (KB) which gives rise to five fragments after cleavage with EcoRI. Only one of the DNA fragments (6.5 Kb) hybridized to the nifHDK genes of Klebsiella pneumoniae. 3 The organization of the nif genes in this DNA fragment was determined using different DNA segments containing the nifH, nifK or nifD genes of K. pneumoniae as probes