Resistance of the alimentary canal of Daphnia magna Straus to the effect of enteropathogenic NAG-vibrios

The interrelations between 30 Daphnias and enteropathogenic NAG-vibrios were experimentally investigated. Using histological and immunoserological techniques, NAG-vibrio administration into the medium inhabited by Crustaceous was shown to cause no pathological changes in the animal alimentary canal. Daphnias used these organisms as food. The intestinal epithelium is well protected from mechanical injury by peritrophic membrane, chitinous lining and peritrophic cavity where digestion takes place.     

Noninvasive Prenatal Testing Using Next Generation Sequencing: Pilot Experience of the D.O. Ott Research Institute of Obstetrics,Gynecology and Reproductology

Russian Journal of Genetics - In recent years, noninvasive prenatal testing (NIPT) for fetal chromosomal abnormalities has come into wide use. NIPT allows detection of fetal chromosomal...     

Peripheral T-cell lymphoma, unspecified--the analysis of the data from the Czech Lymphoma Study Group (CLSG) registry

BACKGROUND: Peripheral T-cell lymphoma, unspecified (PTCL-US) is one of the entities from the infrequent family of nodal mature T-cell lymphomas. The clinical course is aggressive, and despite multiagent chemotherapy, the median survival is about 2 years. Published data are limited to retrospective, mostly single-center studies or reviews and usually include more lymphoma subtypes. AIM: To evaluate the current treatment modalities, clinical outcome and prognostic factors in unselected, new diagnosed patients with PTCL-US in the population of the central european region (Czech Republic). METHOD: Czech Lymphoma Study Group is a national scientific organization which provides an on-line database registry which collects a data about almost all new diagnosed lymphoma patients since year 2000. All diagnostic biopsies were reviewed by a reference pathologist. RESULTS: We analyzed 63 patients with new diagnosis of PTCL-US. The median age was 59 years (25-81), chemotherapy (CHT) was administered in 56 of the 63 patients: anthracyclin-based CHT in 51%, intensive CHT in 21% and non-anthracyclin regimen was applied in 13% of the patients. The overall response rate was 74.4%, (CR in 57.4%). After a median follow-up of 19.6 months, 41% of the patients were in CR, 3.4% in PR or stable disease and 55% of the patients died. The estimated survival probability in 3 years was 36%. Clinical stage (IV) and CR achievement were found to be independent survival predictors in a multivariate analysis. CONCLUSIONS: Although the current treatment modalities are mostly ineffective in PTCL-US, appropriate intensive treatment may lead to prolonged remission but not survival.     

The phosphodiesterase DipA (PA5017) is essential for Pseudomonas aeruginosa biofilm dispersion

Although little is known regarding the mechanism of biofilm dispersion, it is becoming clear that this process coincides with alteration of cyclic di-GMP (c-di-GMP) levels. Here, we demonstrate that dispersion by Pseudomonas aeruginosa in response to sudden changes in nutrient concentrations resulted in increased phosphodiesterase activity and reduction of c-di-GMP levels compared to biofilm and planktonic cells. By screening mutants inactivated in genes encoding EAL domains for nutrient-induced dispersion, we identified in addition to the previously reported ΔrbdA mutant a second mutant, the ΔdipA strain (PA5017 [dispersion-induced phosphodiesterase A]), to be dispersion deficient in response to glutamate, nitric oxide, ammonium chloride, and mercury chloride. Using biochemical and in vivo studies, we show that DipA associates with the membrane and exhibits phosphodiesterase activity but no detectable diguanylate cyclase activity. Consistent with these data, a ΔdipA mutant exhibited reduced swarming motility, increased initial attachment, and polysaccharide production but only somewhat increased biofilm formation and c-di-GMP levels. DipA harbors an N-terminal GAF (cGMP-specific phosphodiesterases, adenylyl cyclases, and FhlA) domain and two EAL motifs within or near the C-terminal EAL domain. Mutational analyses of the two EAL motifs of DipA suggest that both are important for the observed phosphodiesterase activity and dispersion, while the GAF domain modulated DipA function both in vivo and in vitro without being required for phosphodiesterase activity. Dispersion was found to require protein synthesis and resulted in increased dipA expression and reduction of c-di-GMP levels. We propose a role of DipA in enabling dispersion in P. aeruginosa biofilms.     

PAS Domain Residues and Prosthetic Group Involved in BdlA-Dependent Dispersion Response by Pseudomonas aeruginosa Biofilms

Biofilm dispersion by Pseudomonas aeruginosa in response to environmental cues is dependent on the cytoplasmic BdlA protein harboring two sensory PAS domains and a chemoreceptor domain, TarH. The closest known and previously characterized BdlA homolog is the flavin adenine dinucleotide (FAD)-binding Aer, the redox potential sensor and aerotaxis transducer in Escherichia coli. Here, we made use of alanine replacement mutagenesis of the BdlA PAS domain residues previously demonstrated to be essential for aerotaxis in Aer to determine whether BdlA is a potential sensory protein. Five substitutions (D14A, N23A, W60A, I109A, and W182A) resulted in a null phenotype for dispersion. One protein, the BdlA protein with the G31A mutation (BdlA-G31A), transmitted a constant signal-on bias as it rendered P. aeruginosa biofilms hyperdispersive. The hyperdispersive phenotype correlated with increased interaction of BdlA-G31A with the phosphodiesterase DipA under biofilm growth conditions, resulting in increased phosphodiesterase activity and reduced biofilm biomass accumulation. We furthermore demonstrate that BdlA is a heme-binding protein. None of the BdlA protein variants analyzed led to a loss of the heme prosthetic group. The N-terminal PASa domain was identified as the heme-binding domain of BdlA, with BdlA-dependent nutrient-induced dispersion requiring the PASa domain. The findings suggest that BdlA plays a role in intracellular sensing of dispersion-inducing conditions and together with DipA forms a regulatory network that modulates an intracellular cyclic d-GMP (c-di-GMP) pool to enable dispersion.     

Association of chromosome 8q24 variants with prostate cancer risk in the Siberian region of Russia and meta-analysis

Compelling evidence demonstrates the importance of chromosome 8q24 as a locus of susceptibility to prostate cancer. In this work, the association of common 8q24 variants, rs6983267 and rs1447295, with a sporadic risk of prostate cancer was analyzed in the Russian population of Siberia. For this purpose, the above polymorphisms were genotyped in 393 cases and 384 control individuals. The A allele of rs1447295 was significantly associated with prostate cancer risk (OR[CI 95%] = 1.74 [1.26–2.4], p = 7.8 × 10⁻⁴). The common G-A haplotype of rs6983267-rs1447295 also showed association with prostate cancer risk in Russians (OR[CI 95%] = 2.03 [1.1–3.75], p = 0.02). A meta-analysis combining our data with previously published results was performed to better evaluate the association between the SNPs studied and prostate cancer risk; its results strongly supported the association for both loci (p < 10⁻⁶). Thus, our study has confirmed the association of chromosome 8q24 with a risk of prostate cancer.     

Crystal packing modifies ligand binding affinity: the case of aldose reductase

The relationship between the structures of protein-ligand complexes existing in the crystal and in solution, essential in the case of fragment-based screening by X-ray crystallography (FBS-X), has been often an object of controversy. To address this question, simultaneous co-crystallization and soaking of two inhibitors with different ratios, Fidarestat (FID; K(d) = 6.5 nM) and IDD594 (594; K(d) = 61 nM), which bind to h-aldose reductase (AR), have been performed. The subatomic resolution of the crystal structures allows the differentiation of both inhibitors, even when the structures are almost superposed. We have determined the occupation ratio in solution by mass spectrometry (MS) Occ(FID)/Occ(594) = 2.7 and by X-ray crystallography Occ(FID)/Occ(594) = 0.6. The occupancies in the crystal and in solution differ 4.6 times, implying that ligand binding potency is influenced by crystal contacts. A structural analysis shows that the Loop A (residues 122-130), which is exposed to the solvent, is flexible in solution, and is involved in packing contacts within the crystal. Furthermore, inhibitor 594 contacts the base of Loop A, stabilizing it, while inhibitor FID does not. This is shown by the difference in B-factors of the Loop A between the AR-594 and AR-FID complexes. A stable loop diminishes the entropic energy barrier to binding, favoring 594 versus FID. Therefore, the effect of the crystal environment should be taken into consideration in the X-ray diffraction analysis of ligand binding to proteins. This conclusion highlights the need for additional methodologies in the case of FBS-X to validate this powerful screening technique, which is widely used.     

IS<Emphasis Type="Italic">Ppy1</Emphasis>, a novel mobile element of the ancient <Emphasis Type="Italic">Psychrobacter maritimus</Emphasis> permafrost strain: Translocations in <Emphasis Type="Italic">Escherichia coli</Emphasis> K-12 cells and formation of composite transposons

It was shown that IS element ISPpy1 isolated earlier in the permafrost strain Psychrobacter maritimus MR29-12 has a high level of functional activity in cells of the heterologous host Escherichia coli K-12. ISPpy1 can be translocated in E. coli cells by itself and mobilize adjacent genes and can also form composite transposons flanked by two copies of this element. Apart from translocations between different plasmids, the composite ISPpy1-containing transposon Tn5080a is capable of translocation from the plasmid into the E. coli chromosome with high frequency and from the chromosome into the plasmid. Among products of Tn5080a transposition into plasmid R388, simple insertions were predominantly formed together with cointegrates. Upon mobilization of adjacent genes with the use of one ISPpy1 copy, only cointegrates arise.     

Analysis of polymorphism at nine nuclear genome DNA loci in maris

Population genetic survey of the indigenous populations of the Marii El Republic, represented by the two major ethnographic groups of Maris, Meadow (five samples from Morkinsk, Orshansk, Semursk, Sovetsk, and Zvenigovsk districts) and Mountain (one sample from Gornomariisk district) Maris, was carried out. All Mari groups were examined at nine polymorphic DNA loci of nuclear genome, VNTR(PAH) (N = 422), STR(PAH) (N = 152), VNTR(ApoB) (N= 294), VNTR(DAT1) (N = 363), VNTR(eNOS) (N = 373), ACE (N = 412), IVS6aGATT (N = 513), D7S23(KM.19) (N = 494), and D7S8 (N = 366). Allele and genotype frequency distribution patterns were obtained for individual samples and ethnographic groups, as well as for the ethnic group overall. In each of six Mari samples examined, the deficit of heterozygotes was observed, i.e., the mean observed heterozygosity was lower than the expected one. The indices of mean heterozygosity, Hs = 0.455, and interpopulation differentiation, FST = 0.0024, for the Mari gene pool were obtained using a set of DNA markers analyzed. Analysis of the genetic distances and between population differentiation (FST) showed that the main part of genetic diversity in Maris was determined by the differentiation between the populations of Meadow Maris. The contribution of the differences between the ethnographic groups of Mountain and Meadow Maris to the ethnic gene pool was small. It is suggested that the main role in the formation of the Mari gene pool is played by the geographic factor.