The stress responsive and morphologically regulated <Emphasis Type="Italic">hsp90</Emphasis> gene from <Emphasis Type="Italic">Paracoccidioides brasiliensis</Emphasis> is essential to cell viability

Background  

Paracoccidioides brasiliensis is a dimorphic fungus that causes the most prevalent systemic mycosis in Latin America. The response to heat shock is involved in pathogenesis, as this pathogen switches from mycelium to yeast forms in a temperature dependent fashion that is essential to establish infection. HSP90 is a molecular chaperone that helps in the folding and stabilization of selected polypeptides. HSP90 family members have been shown to present important roles in fungi, especially in the pathogenic species, as an immunodominant antigen and also as a potential antifungal therapeutic target.     

Effect of ribonucleases on humoral immunity of experimental animals

The stimulating effect of RNAases on the humoral immune response was observed in experiments with animals. It was shown that the stimulation was mainly mediated by the system of T-lymphocytes. In the T-lymphocyte system positive sensitivity to the enzymes was attributed to the T-helper cell subpopulation.     

Expert opinion as 'validation' of risk assessment applied to calf welfare

Background  

Recently, a Risk Assessment methodology was applied to animal welfare issues in a report of the European Food Safety Authority (EFSA) on intensively housed calves.     

Antitumor action of RNAses modified by covalent binding with dextran m-aminobenzylhydroxymethyl ether

Antitumor effect of pancreatic RNase and RNase from Actinomyces rimosus, as well as of their derivatives modified by dextran m-aminobenzylhydroxymethyl ether under different conditions was studied and compared. It was found that the efficacy of actinomycetous enzyme and its modified derivatives was superior to that of the analogous preparations of pancreatic RNase. Antitumor effect of the modified enzymes was higher than that of the native ones and depended on the modification conditions. It is concluded that biological efficacy of the RNases is determined by their origin and physico-chemical properties.     

Induction of the unculturable state in <Emphasis Type="Italic">Escherichia coli</Emphasis> K12 with 2,4,6-trinitrotoluene

The toxic effect of high (200 mg/l) 2,4,6-trinitrotoluene (TNT) concentrations on Escherichia coli K12 cells in the absence of exogenous nutrient sources (incubation in 0.5% NaCl) was shown to manifest itself in the transfer of the culture to an unculturable but viable state; its reversal depends on the duration of culture contact with the xenobiotic and the conditions of cell recultivation. The likelihood that cell succession to death forms the basis of the physiologo-biochemical mechanism of the unculturable state in Escherichia coli K12 population under conditions of combined toxic and starvation stress is discussed.     

Assessment of changes in the brca2 and p53 genes in breast invasive ductal carcinoma in northeast Brazil

Background

BRCA protein interacts with at least 13 different proteins that have been implicated with cancer susceptibility and loss of BRCA function is correlated to sensitivity to DNA crosslinking agents in preclinical models.

Results

BRCA2 methylation frequency was 44%, p53 Pro22 allele frequency was 32% and heterozygous frequency of Arg/Pro72 genotype was 60% which could be associated as risk factor for metastasis (p = 0.046 OR = 4.190). Regarding to polymorphism of codon 249 the frequency of Arg249 allele presented 82% which was considered not statistically significant.

Conclusions

There was not statistical significance to BRCA2 promoter methylation with any parameters chosen. However, our findings suggest that patients who present heterozygous genotype at codon 72 of p53 gene may have a major susceptibility to any type of metastasis and this could serve as potential auxiliary biomarker for poor prognosis.     

Electrostatic interaction of pancreatic and microbial ribonucleases with macrophages in vitro

The interaction of RNase A and RNase Bacillus intermedius with peritoneal macrophage of rats has been studied. To estimate the efficiency of this interaction the spontaneous chemiluminescence and induced by phagocytosis chemiluminescence of macrophages were investigated. It has been shown that electrostatic interaction of enzyme proteins with negatively charged cell membrane makes substantional contribution to the development of chemiluminescence reply of macrophages. The RNase A, which is more basical than the other (i. e. it has larger value of pI) is less effective with respect to macrophages. The calculation of total charge and dipole moment of pancreatic and microbial RNases showed that the efficiency of interaction between protein polycation and a cell was not connected with pI and depended on the charge and its distribution on the surface of protein molecule at the given pH value.     

Molecular evolution of a Y-chromosomal repetitive sequence family in the genus Mus

A 522-base-long Y-chromosomal sequence was isolated from a BALB/c genomic library and was designated "BF046." It is repeated about 200 times in the male genome, and a difference was detected between the Mus musculus musculus and the M. m. domesticus type Y chromosomes. BF046- related sequences were present over the entire length of the Y chromosome as visualized by in situ hybridization. Southern blot analysis against DNAs isolated from eight species in the genus Mus showed that BF046-related sequences were amplified in the Y chromosomes of three closely related species: M. musculus, M. spicilegus, and M. spretus. To gain insight into the stability of the BF046 sequence family, we isolated 18 additional clones from these three mouse species and compared their sequences. The M. musculus sequences differed from the M. spicilegus and M. spretus sequences by two indels. The remaining parts of the sequences were very similar, but both parsimony and distance-based analytical methods divided the sequences into the same four subgroups, with each species having its own subgroup(s). Thus, the Y chromosomes of M. musculus, M. spicilegus, and M. spretus can be distinguished from one another.      

Sensitivity of various escherichia coli strains to 2,4,6-trinitrotoluene

The sensitivity of Escherichia coli strains K-12 and 055 to 2,4,6-trinitrotoluene (TNT) was found to correlate with the structural and functional properties of the outer lipoprotein membrane. The protective ability of the membrane of strain 055 is much lower than that of K-12. This is the cause of the greater sensitivity of 055 to the toxic action of TNT. High TNT concentrations (100-200 mg/l) suppressed the growth of 055, whereas K-12 grew at all TNT concentrations studied. Both strains adapted to high TNT concentrations by converting it by either nitroreduction or denitritation depending on concentration. The denitritation system of strain 055 started TNT degradation earlier than that of K-12.