T-cell independent Thy-1 allo-antibody response with the use of transgenic mice.

We have introduced a mouse Thy-1.1 gene into the germline of Thy-1.2 mice. The introduced gene was shown to be expressed at very high levels in thymocytes when compared with the endogenous gene. Transgenic thymocytes were shown to evoke a higher than normal primary anti-Thy-1.1 antibody response in plaque-forming cell (PFC) assays. This result suggests that a direct quantitative interaction of the Thy-1 antigen activates the B cell response

A new approach to in silico SNP detection and some new SNPs in the Bacillus anthracis genome

<p>Abstract</p> <p>Background</p> <p><it>Bacillus anthracis </it>is one of the most monomorphic pathogens known. Identification of polymorphisms in its genome is essential for taxonomic classification, for determination of recent evolutionary changes, and for evaluation of pathogenic potency.</p> <p>Findings</p> <p>In this work three strains of the <it>Bacillus anthracis </it>genome are compared and previously unpublished single nucleotide polymorphisms (SNPs) are revealed. Moreover, it is shown that, despite the highly monomorphic nature of <it>Bacillus anthracis</it>, the SNPs are (1) abundant in the genome and (2) distributed relatively uniformly across the sequence.</p> <p>Conclusions</p> <p>The findings support the proposition that SNPs, together with indels and variable number tandem repeats (VNTRs), can be used effectively not only for the differentiation of perfect strain data, but also for the comparison of moderately incomplete, noisy and, in some cases, unknown <it>Bacillus anthracis </it>strains. In the case when the data is of still lower quality, a new DNA sequence fingerprinting approach based on recently introduced markers, based on combinatorial-analytic concepts and called cyclic difference sets, can be used.</p

SuperCAT: a supertree database for combined and integrative multilocus sequence typing analysis of the Bacillus cereus group of bacteria (including B. cereus, B. anthracis and B. thuringiensis)

The Bacillus cereus group of bacteria is an important group including mammalian and insect pathogens, such as B. anthracis, the anthrax bacterium, B. thuringiensis, used as a biological pesticide and B. cereus, often involved in food poisoning incidents. To characterize the population structure and epidemiology of these bacteria, five separate multilocus sequence typing (MLST) schemes have been developed, which makes results difficult to compare. Therefore, we have developed a database that compiles and integrates MLST data from all five schemes for the B. cereus group, accessible at http://mlstoslo.uio.no/. Supertree techniques were used to combine the phylogenetic information from analysis of all schemes and datasets, in order to produce an integrated view of the B. cereus group population. The database currently contains strain information and sequence data for 1029 isolates and 26 housekeeping gene fragments, which can be searched by keywords, MLST scheme, or sequence similarity. Supertrees can be browsed according to various criteria such as species, isolate source, or genetic distance, and subtrees containing strains of interest can be extracted. Besides analysis of the available data, the user has the possibility to enter her/his own sequences and compare them to the database and/or include them into the supertree reconstructions

IlsA, A Unique Surface Protein of Bacillus cereus Required for Iron Acquisition from Heme, Hemoglobin and Ferritin

The human opportunistic pathogen Bacillus cereus belongs to the B. cereus group that includes bacteria with a broad host spectrum. The ability of these bacteria to colonize diverse hosts is reliant on the presence of adaptation factors. Previously, an IVET strategy led to the identification of a novel B. cereus protein (IlsA, Iron-regulated leucine rich surface protein), which is specifically expressed in the insect host or under iron restrictive conditions in vitro. Here, we show that IlsA is localized on the surface of B. cereus and hence has the potential to interact with host proteins. We report that B. cereus uses hemoglobin, heme and ferritin, but not transferrin and lactoferrin. In addition, affinity tests revealed that IlsA interacts with both hemoglobin and ferritin. Furthermore, IlsA directly binds heme probably through the NEAT domain. Inactivation of ilsA drastically decreases the ability of B. cereus to grow in the presence of hemoglobin, heme and ferritin, indicating that IlsA is essential for iron acquisition from these iron sources. In addition, the ilsA mutant displays a reduction in growth and virulence in an insect model. Hence, our results indicate that IlsA is a key factor within a new iron acquisition system, playing an important role in the general virulence strategy adapted by B. cereus to colonize susceptible hosts

The maintenance of methylation-free islands in transgenic mice.

The Thy-1 gene is expressed in a tissue- and stage-specific pattern and has a typical 1.6kb methylation-free island (MFI) covering about 600bp upstream and downstream of the two alternative first exons. By microinjection of a mouse Thy-1.1/human Thy-1 gene into fertilized eggs, we were able to show that the MFI is restored in the transgenic mice. The flanking sequence became methylated, but the MFI remains unmethylated in all tissues of transgenic mice at different developmental stages tested, irrespective of the site of expression of the gene. There is one exception, in extra-embryonal tissues of 14.5 day embryos a small percentage of the islands were methylated. We conclude that maintenance of the MFI is regulated by cis-acting sequences present within the gene, and indicates that the unmethylated state of the islands is consistent with a necessary but not sufficient condition for expression of the gene

'Exit' in deeply divided societies: regimes of discrimination in Estonia and Latvia and the potential for Russophone migration

Hirschman’s model of ‘exit’ envisages that mass migration can communicate feedback to a state and elicit modifying policy behaviour. The regimes of discrimination against Russophones in Estonia and Latvia are examined to demonstrate that in certain conditions of inter-ethnic conflict the model does not work as predicted. In deeply divided societies the mass migration of a minority can be intentionally promoted by a majority regime of discrimination and thus does not perform a feedback function. Equally, in such conditions migration may operate as a safety valve to release the build up of minority antagonisms against the discriminatory regimes. The cases of Estonia and Latvia also illustrate the limitations of international conditionality from the EU and OSCE to prevent anti-minority policies, when there is a lack of international commitment and when governing elites resist. Given the lack of political will in Estonia and Latvia to modify the regimes of discrimination, and the poor prospects for integration or assimilation, the article predicts a significant out-migration by Russophones to other EU member states when restrictions on freedom of movement are eased after the transitional period