64 research outputs found
Expression of oxidative stress and antioxidant defense genes in the kidney of inbred mice after intestinal ischemia and reperfusion
Karyotype composition of some rodents and marsupials from Chapada Diamantina (Bahia, Brasil)
Total Hadronic Cross Section Data and the Froissart-Martin Bound
The energy dependence of the total hadronic cross section at high energies is
investigated with focus on the recent experimental result by the TOTEM
Collaboration at 7 TeV and the Froissart-Martin bound. On the basis of a class
of analytical parametrization with the exponent in the leading
logarithm contribution as a free parameter, different variants of fits to
and total cross section data above 5 GeV are developed. Two
ensembles are considered, the first comprising data up to 1.8 TeV, the second
also including the data collected at 7 TeV. We shown that in all fit variants
applied to the first ensemble the exponent is statistically consistent with
= 2. Applied to the second ensemble, however, the same variants yield
's above 2, a result already obtained in two other analysis, by U.
Amaldi \textit{et al}. and by the UA4/2 Collaboration. As recently discussed by
Ya. I. Azimov, this faster-than-squared-logarithm rise does not necessarily
violate unitarity. Our results suggest that the energy dependence of the
hadronic total cross section at high energies still constitute an open problem.Comment: 20 pages, 10 figures, introduction extended and general references
added to match editorial style, to appear in the Brazilian Journal of Physic
Gene expression profile of oxidative stress in the lung of inbred mice after intestinal ischemia/reperfusion injury
Patterns of Polymorphism and Demographic History in Natural Populations of Arabidopsis lyrata
Many of the processes affecting genetic diversity act on local populations. However, studies of plant nucleotide diversity have largely ignored local sampling, making it difficult to infer the demographic history of populations and to assess the importance of local adaptation. Arabidopsis lyrata, a self-incompatible, perennial species with a circumpolar distribution, is an excellent model system in which to study the roles of demographic history and local adaptation in patterning genetic variation.We studied nucleotide diversity in six natural populations of Arabidopsis lyrata, using 77 loci sampled from 140 chromosomes. The six populations were highly differentiated, with a median FST of 0.52, and structure analysis revealed no evidence of admixed individuals. Average within-population diversity varied among populations, with the highest diversity found in a German population; this population harbors 3-fold higher levels of silent diversity than worldwide samples of A. thaliana. All A. lyrata populations also yielded positive values of Tajima's D. We estimated a demographic model for these populations, finding evidence of population divergence over the past 19,000 to 47,000 years involving non-equilibrium demographic events that reduced the effective size of most populations. Finally, we used the inferred demographic model to perform an initial test for local adaptation and identified several genes, including the flowering time gene FCA and a disease resistance locus, as candidates for local adaptation events.Our results underscore the importance of population-specific, non-equilibrium demographic processes in patterning diversity within A. lyrata. Moreover, our extensive dataset provides an important resource for future molecular population genetic studies of local adaptation in A. lyrata
Muc2 Protects against Lethal Infectious Colitis by Disassociating Pathogenic and Commensal Bacteria from the Colonic Mucosa
Despite recent advances in our understanding of the pathogenesis of attaching and effacing (A/E) Escherichia coli infections, the mechanisms by which the host defends against these microbes are unclear. The goal of this study was to determine the role of goblet cell-derived Muc2, the major intestinal secretory mucin and primary component of the mucus layer, in host protection against A/E pathogens. To assess the role of Muc2 during A/E bacterial infections, we inoculated Muc2 deficient (Muc2−/−) mice with Citrobacter rodentium, a murine A/E pathogen related to diarrheagenic A/E E. coli. Unlike wildtype (WT) mice, infected Muc2−/− mice exhibited rapid weight loss and suffered up to 90% mortality. Stool plating demonstrated 10–100 fold greater C. rodentium burdens in Muc2−/− vs. WT mice, most of which were found to be loosely adherent to the colonic mucosa. Histology of Muc2−/− mice revealed ulceration in the colon amid focal bacterial microcolonies. Metabolic labeling of secreted mucins in the large intestine demonstrated that mucin secretion was markedly increased in WT mice during infection compared to uninfected controls, suggesting that the host uses increased mucin release to flush pathogens from the mucosal surface. Muc2 also impacted host-commensal interactions during infection, as FISH analysis revealed C. rodentium microcolonies contained numerous commensal microbes, which was not observed in WT mice. Orally administered FITC-Dextran and FISH staining showed significantly worsened intestinal barrier disruption in Muc2−/− vs. WT mice, with overt pathogen and commensal translocation into the Muc2−/− colonic mucosa. Interestingly, commensal depletion enhanced C. rodentium colonization of Muc2−/− mice, although colonic pathology was not significantly altered. In conclusion, Muc2 production is critical for host protection during A/E bacterial infections, by limiting overall pathogen and commensal numbers associated with the colonic mucosal surface. Such actions limit tissue damage and translocation of pathogenic and commensal bacteria across the epithelium
Feeding management strategy for male broiler breeders and its effects on body weight, hatchability and fertility
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