Abstract
We evaluated a biochemical assay based on the ability to metabolise β-phenylpropionic acid (PPA) as a diagnostic aid in the identification of typical enteropathogenic Escherichia coli (EPEC) ...strains. A total of 1061 E. coli strains of serogroups O55, O111, and O119 were initially characterised regarding their H types (serotypes) and the presence of EPEC DNA sequences, eae, EAF, and bfpA. In case of the serogroup O111 strains, 84.6% carried the typical EPEC markers, and the great majority of those (98.1%) were PPA-positive. In contrast, only 0.9% of the serogroups O55 and O119 strains carrying the typical EPEC markers (53.6% and 75.4%, respectively) were PPA-positive. We conclude that the PPA test is a useful method to detect typical EPEC strains only among strains of the O111 serogroup.
Arrestin is a component of the light transduction cascade that takes place in the outer segment of retinal rods. In situ hybridization and linkage analysis have localized the arrestin gene to a ...region of 50 cM between CRYG alpha and D2S23/D2S55 on chromosome 2q24-37. We have performed pairwise and multipoint linkage analysis between arrestin and four highly polymorphic markers from this region. The results indicate tight linkage between the gene and the microsatellite D2S172 (Zmax = 9.25 at theta = 0.038). This fine localization of the gene should provide a useful tool for cosegregation analyses involving the arrestin gene.
A full length cDNA encoding a novel Trypanosoma cruzi DnaJ protein was cloned and characterized. The 324 amino acid protein encoded by the cDNA (TcDJ1) displays a characteristic J‐domain, but lacks ...the Gly‐Phe and zinc finger regions present in some other DnaJ proteins. Relative to four other T. cruzi DnaJ proteins, TcDJ1 has an amino terminal extension containing basic and hydroxylated residues characteristic of mitochondrial import peptides. A T. cruzi transfectant expressing epitope‐tagged TcDJ1 was generated and subcellular fractions were produced. Western blot analysis revealed that the protein has a molecular mass of 29 kDa and is found in the mitochondrial fraction. The expression of TcDJ1 is developmentally regulated since the levels of both mRNA and protein are much higher in epimastigotes (replicative form) than in metacyclic trypomastigotes (infective form). Thus it may participate in mitochondrial biosynthetic processes in this organism.
Abstract
Escherichia coli strains of non-EPEC serotypes that carry eae and lack the EAF and the Shiga toxin (stx) gene sequences have been found in acute diarrhea. Both the cell association and the ...cell entry of these strains in human intestinal epithelial cells were studied as a function of cell differentiation and polarization. The eae+/EAF−/stx − non-EPEC E. coli strains invaded undifferentiated Caco-2 cells more efficiently than differentiated cells. In contrast, prototype EPEC strain E2348/69 did not show significative differences from invasion rates of undifferentiated and differentiated cells. The uptake of these strains was greatly enhanced by pretreatment of differentiated Caco-2 cells with EGTA. These results suggest that the eae+/EAF−/stx − non-EPEC E. coli invasion of intestinal cells may be dependent on receptors expressed on the surface of undifferentiated cells and the basolateral pole of differentiated cells.
Using the charcoal assay to separate free from bound hormone, the results showed that there is a high binding of IAA to cytosol proteins. Competition experiments were carried out using compounds with ...different auxin activity (indole-acetic acid, alphanaphtalene acetic acid, indole-butyric acid and phenyl-acetic acid), revealing that specificity of binding exists for those compounds with a molecular configuration appropiate for auxin activity. The protein nature of the indoleacetic acid-binding molecule was demonstrated by the use of enzymes and by its thermolability.
The aim of this study was to estimate (co)variance components and genetic parameters (heritability and genetic correlations) for meat fatty acid composition in Nellore cattle. The fatty acids ...analyzed were: conjugated linoleic acid - CLA (C18:2 trans-10 cis-12), palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1 cis-9), linoleic acid (C18:2 cis- 9-12) and linolenic acid (C18:3). A total of 751 Nellore bulls, finished in feedlot for at least 90 days, with average age at slaughter of 24 months were used. The animals belong to eight farms located in the Southeast, Northeast and Midwest regions, of São Paulo State, which comprise three specific genetic breeding programs. The fatty acid determination was carried out at the Laboratory of Meat Science (LCC), Department of Animal Production and Nutrition FMVZ/USP. Samples from theLongissimus muscle were collected 48 hours after slaughter. The determination of meat fatty acid profile was performed by the method of Folch et al. (1957) and Kramer et al. (1997). Fatty acids were quantified by gas chromatography (GC-2010 Plus - Shimadzu AOC 20i auto sampler) using SP-2560 capillary column (100 m × 0.25 mm in diameter with 0.02 mm thickness, Supelco, Bellefonte, PA). To estimate the (co) variance components and genetic parameters, the model included the additive genetic effect as random effect, and the fixed effects of the contemporary group and animal's age at slaughter as a covariable (linear effect). The model used for the estimation of the included random direct genetic effect, the fixed effect of the GC, and the animal's age at slaughter as a covariate (linear effect).The (co)variance components and genetic parameters were estimated by Bayesian inference with a linear multi-trait animal model, using the GIBBS2F90 program. The convergence of the data was verified using the R software package analyzed with the Bayesian Output Analysis (BOA) of the R 2.9.0 software (The R Development Core Team, 2009). Heritability estimates obtained for the fatty acids analyzed were: 0.52; 0.26; 0.68; 0.57; 0.46 and 0.41 for CLA, palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, respectively. The genetic correlation estimates between the palmitic acid (C16: 0) with stearic acid, oleic acid, linoleic acid, linolenic acid and CLA showed the following values: 0.14; 0.39; -0.09; -0.33; 0.34. The genetic correlation estimates between the stearic acid with oleic acid, linoleic acid, linolenic acid and CLA were 0.24, -0.06, -0.21 and 0.22, respectively. For the oleic acid, the genetic correlation estimates were -0.04, -0.02 and -0.02, with the linoleic acid, linolenic acid and CLA, respectively. The genetic correlation estimated between the linolenic acid and CLA was close to zero. Most of the genetic correlations estimates between fatty acids were low to moderate. The heritability estimates for fatty acids were moderate to high, indicating that these traits would respond rapidly to selection. The genetic correlation estimates between fatty acids with different degrees of saturation suggest that indirect selection to improve the meat fatty acid composition is possible.
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