Development of a surface plasmon resonance biosensor for the identification of Campylobacter jejuni

The purpose of this study was to develop a biosensor based on surface plasmon resonance (SPR) for the rapid identification of C. jejuni in broiler samples. We examined the specificity and sensitivity of commercial antibodies against C. jejuni with six Campylobacter strains and six non-Campylobacter bacterial strains. Antigen-antibody interactions were studied using enzyme-linked immunosorbent assay (ELISA) and a commercially available SPR biosensor platform (Spreeta). Campylobacter cells killed with 0.5% formalin had significant lower antibody reactivity when compared to live cells, or cells inactivated with 0.5% thimerosal or heat (70 degrees C for 3 min) using ELISA. The SPR biosensor showed a good sensitivity with commercial antibodies against C. jejuni at 10(3) CFU/ml and a low cross reactivity with Salmonella serotype typhimurium. The sensitivity of the SPR was similar when testing spiked broiler meat samples. However, research is still needed to reduce the high background observed when sampling meat products.     

The estimation of current state of Lake Ladoga using mathematical models

This paper describes a mathematical simulation model of the transformation of organic matter and biogenic compounds. The model is validated with observations made on Lake Ladoga. Despite the approximate nature of the biogenic load data, a good agreement is obtained between the calculated substance concentrations and available observations made during individual seasons for different areas of the lake. The model was developed by the author Leonov and this paper presents new model results with accurate formulations for nitrogen and carbon components. Comparison with observational data base collected during 1976–1979 shows that the model results provide good simulation of the annual seasonal changes in material concentrations in the identified regions of the lake.     

Protein database searches using compositionally adjusted substitution matrices

Almost all protein database search methods use amino acid substitution matrices for scoring, optimizing, and assessing the statistical significance of sequence alignments. Much care and effort has therefore gone into constructing substitution matrices, and the quality of search results can depend strongly upon the choice of the proper matrix. A long-standing problem has been the comparison of sequences with biased amino acid compositions, for which standard substitution matrices are not optimal. To address this problem, we have recently developed a general procedure for transforming a standard matrix into one appropriate for the comparison of two sequences with arbitrary, and possibly differing compositions. Such adjusted matrices yield, on average, improved alignments and alignment scores when applied to the comparison of proteins with markedly biased compositions. Here we review the application of compositionally adjusted matrices and consider whether they may also be applied fruitfully to general purpose protein sequence database searches, in which related sequence pairs do not necessarily have strong compositional biases. Although it is not advisable to apply compositional adjustment indiscriminately, we describe several simple criteria under which invoking such adjustment is on average beneficial. In a typical database search, at least one of these criteria is satisfied by over half the related sequence pairs. Compositional substitution matrix adjustment is now available in NCBI's protein-protein version of blast.     

Domestic pigs have low susceptibility to H5N1 highly pathogenic avian influenza viruses

Genetic reassortment of H5N1 highly pathogenic avian influenza viruses (HPAI) with currently circulating human influenza A strains is one possibility that could lead to efficient human-to-human transmissibility. Domestic pigs which are susceptible to infection with both human and avian influenza A viruses are one of the natural hosts where such reassortment events could occur. Virological, histological and serological features of H5N1 virus infection in pigs were characterized in this study. Two- to three-week-old domestic piglets were intranasally inoculated with 10(6) EID(50) of A/Vietnam/1203/04 (VN/04), A/chicken/Indonesia/7/03 (Ck/Indo/03), A/Whooper swan/Mongolia/244/05 (WS/Mong/05), and A/Muscovy duck/Vietnam/ 209/05 (MDk/VN/05) viruses. Swine H3N2 and H1N1 viruses were studied as a positive control for swine influenza virus infection. The pathogenicity of the H5N1 HPAI viruses was also characterized in mouse and ferret animal models. Intranasal inoculation of pigs with H5N1 viruses or consumption of infected chicken meat did not result in severe disease. Mild weight loss was seen in pigs inoculated with WS/Mong/05, Ck/Indo/03 H5N1 and H1N1 swine influenza viruses. WS/Mong/05, Ck/Indo/03 and VN/04 viruses were detected in nasal swabs of inoculated pigs mainly on days 1 and 3. Titers of H5N1 viruses in nasal swabs were remarkably lower compared with those of swine influenza viruses. Replication of all four H5N1 viruses in pigs was restricted to the respiratory tract, mainly to the lungs. Titers of H5N1 viruses in the lungs were lower than those of swine viruses. WS/Mong/05 virus was isolated from trachea and tonsils, and MDk/VN/05 virus was isolated from nasal turbinate of infected pigs. Histological examination revealed mild to moderate bronchiolitis and multifocal alveolitis in the lungs of pigs infected with H5N1 viruses, while infection with swine influenza viruses resulted in severe tracheobronchitis and bronchointerstitial pneumonia. Pigs had low susceptibility to infection with H5N1 HPAI viruses. Inoculation of pigs with H5N1 viruses resulted in asymptomatic to mild symptomatic infection restricted to the respiratory tract and tonsils in contrast to mouse and ferrets animal models, where some of the viruses studied were highly pathogenic and replicated systemically.     

Design of a brain-penetrant CDK4/6 inhibitor for glioblastoma

CDK4 and CDK6 are kinases with similar sequences that regulate cell cycle progression and are validated targets in the treatment of cancer. Glioblastoma is characterized by a high frequency of CDKN2A/CCND2/CDK4/CDK6 pathway dysregulation, making dual inhibition of CDK4 and CDK6 an attractive therapeutic approach for this disease. Abemaciclib, ribociclib, and palbociclib are approved CDK4/6 inhibitors for the treatment of HR+/HER2? breast cancer, but these drugs are not expected to show strong activity in brain tumors due to poor blood brain barrier penetration. Herein, we report the identification of a brain-penetrant CDK4/6 inhibitor derived from a literature molecule with low molecular weight and topological polar surface area (MW = 285 and TPSA = 66 Ų), but lacking the CDK2/1 selectivity profile due to the absence of a basic amine. Removal of a hydrogen bond donor via cyclization of the pyrazole allowed for the introduction of basic and semi-basic amines, while maintaining in many cases efflux ratios reasonable for a CNS program. Ultimately, a basic spiroazetidine (cpK_a = 8.8) was identified that afforded acceptable selectivity over anti-target CDK1 while maintaining brain-penetration in vivo (mouse K_p,uu = 0.20–0.59). To probe the potency and selectivity, our lead compound was evaluated in a panel of glioblastoma cell lines. Potency comparable to abemaciclib was observed in Rb-wild type lines U87MG, DBTRG-05MG, A172, and T98G, while Rb-deficient cell lines SF539 and M059J exhibited a lack of sensitivity.     

Resistance of the target islet tissue to autoimmune destruction contributes to genetic susceptibility in Type 1 diabetes

   

Type 1 diabetes occurs when self-reactive T lymphocytes destroy the insulin-producing islet β cells of the pancreas. The defects causing this disease have often been assumed to occur exclusively in the immune system. We present evidence that genetic variation at the Idd9 diabetes susceptibility locus determines the resilience of the targets of autoimmunity, the islets, to destruction. Susceptible islets exhibit hyper-responsiveness to inflammatory cytokines resulting in enhanced cell death and increased expression of the death receptor Fas. Fas upregulation in β cells is mediated by TNFR2, and colocalization of TNFR2 with the adaptor TRAF2 in NOD β cells is altered. TNFR2 lies within the candidate Idd9 interval and the diabetes-associated variant contains a mutation adjacent to the TRAF2 binding site. A component of diabetes susceptibility may therefore be determined by the target of the autoimmune response, and protective TNFR2 signaling in islets inhibit early cytokine-induced damage required for the development of destructive autoimmunity.     

Climate and cyclic hydrobiological changes of the Barents Sea from the twentieth to twenty-first centuries

The Barents Sea is a transition zone between North Atlantic and Arctic waters, so its marine ecosystem is highly sensitive to climate dynamics. Understanding of marine biota response to climate changes is necessary to assess the environmental stability and the state of marketable biological resources. These processes are analyzed using a database from the Murmansk Marine Biological Institute which holds oceanographic and hydrobiological data sets collected for more than 100?years along the meridional Kola Transect in the Barents Sea. The data demonstrate high variability in thermal state of the upper layer of the Barents Sea, which is regulated by varying the inflow of Atlantic water and by regional climate. At irregular intervals, cold periods with extended seasonal ice cover are followed by warm periods. The most recent warm period started in the late 1980s and reached its maximum from 2001 to 2006. These cyclic changes in hydrologic regime across the twentieth century and first decade of the twenty-first century are reflected (with a specific lag of 1–5?years) by changes in species composition, as well as abundance and distribution of boreal and arctic groups of macrozoobenthos and fish fauna. For instance, cod and cod fisheries in the Barents Sea are closely linked to the marine climate. Furthermore, Kamchatka crab stock recruitment benefited from the warm climate of 1989 and 1990. In general, studies in this region have shown that climatic dynamics may be assessed using biological indices of abundance, biomass, and migration of marine organisms, including commercial species.