InvB is required for type III-dependent secretion of SopA in Salmonella enterica serovar Typhimurium.

The Salmonella effector protein SopA is translocated into host cells via the SPI-1 type III secretion system (TTSS) and contributes to enteric disease. We found that the chaperone InvB binds to SopA and slightly stabilizes it in the bacterial cytosol and that it is required for its transport via the SPI-1 TTSS.

Role of the Salmonella pathogenicity island 1 effector proteins SipA, SopB, SopE, and SopE2 in Salmonella enterica subspecies 1 serovar Typhimurium colitis in streptomycin-pretreated mice.

Salmonella enterica subspecies 1 serovar Typhimurium (serovar Typhimurium) induces enterocolitis in humans and cattle. The mechanisms of enteric salmonellosis have been studied most extensively in calf infection models. The previous studies established that effector protein translocation into host cells via the Salmonella pathogenicity island 1 (SPI-1) type III secretion system (TTSS) is of central importance in serovar Typhimurium enterocolitis. We recently found that orally streptomycin-pretreated mice provide an alternative model for serovar Typhimurium colitis. In this model the SPI-1 TTSS also plays a key role in the elicitation of intestinal inflammation. However, whether intestinal inflammation in calves and intestinal inflammation in streptomycin-pretreated mice are induced by the same SPI-1 effector proteins is still unclear. Therefore, we analyzed the role of the SPI-1 effector proteins SopB/SigD, SopE, SopE2, and SipA/SspA in elicitation of intestinal inflammation in the murine model. We found that sipA, sopE, and, to a lesser degree, sopE2 contribute to murine colitis, but we could not assign an inflammation phenotype to sopB. These findings are in line with previous studies performed with orally infected calves. Extending these observations, we demonstrated that in addition to SipA, SopE and SopE2 can induce intestinal inflammation independent of each other and in the absence of SopB. In conclusion, our data corroborate the finding that streptomycin-pretreated mice provide a useful model for studying the molecular mechanisms of serovar Typhimurium colitis and are an important starting point for analysis of the molecular events triggered by SopE, SopE2, and SipA in vivo.

Pretreatment of mice with streptomycin provides a Salmonella enterica serovar Typhimurium colitis model that allows analysis of both pathogen and host.

Salmonella enterica subspecies 1 serovar Typhimurium is a principal cause of human enterocolitis. For unknown reasons, in mice serovar Typhimurium does not provoke intestinal inflammation but rather targets the gut-associated lymphatic tissues and causes a systemic typhoid-like infection. The lack of a suitable murine model has limited the analysis of the pathogenetic mechanisms of intestinal salmonellosis. We describe here how streptomycin-pretreated mice provide a mouse model for serovar Typhimurium colitis. Serovar Typhimurium colitis in streptomycin-pretreated mice resembles many aspects of the human infection, including epithelial ulceration, edema, induction of intercellular adhesion molecule 1, and massive infiltration of PMN/CD18(+) cells. This pathology is strongly dependent on protein translocation via the serovar Typhimurium SPI1 type III secretion system. Using a lymphotoxin beta-receptor knockout mouse strain that lacks all lymph nodes and organized gut-associated lymphatic tissues, we demonstrate that Peyer's patches and mesenteric lymph nodes are dispensable for the initiation of murine serovar Typhimurium colitis. Our results demonstrate that streptomycin-pretreated mice offer a unique infection model that allows for the first time to use mutants of both the pathogen and the host to study the molecular mechanisms of enteric salmonellosis.

Elevated temperature differentially affects virulence, VirB protein accumulation, and T-pilus formation in different Agrobacterium tumefaciens and Agrobacterium vitis strains.

That gene transfer to plant cells is a temperature-sensitive process has been known for more than 50 years. Previous work indicated that this sensitivity results from the inability to assemble a functional T pilus required for T-DNA and protein transfer to recipient cells. The studies reported here extend these observations and more clearly define the molecular basis of this assembly and transfer defect. T-pilus assembly and virulence protein accumulation were monitored in Agrobacterium tumefaciens strain C58 at different temperatures ranging from 20 degrees C to growth-inhibitory 37 degrees C. Incubation at 28 degrees C but not at 26 degrees C strongly inhibited extracellular assembly of the major T-pilus component VirB2 as well as of pilus-associated protein VirB5, and the highest amounts of T pili were detected at 20 degrees C. Analysis of temperature effects on the cell-bound virulence machinery revealed three classes of virulence proteins. Whereas class I proteins (VirB2, VirB7, VirB9, and VirB10) were readily detected at 28 degrees C, class II proteins (VirB1, VirB4, VirB5, VirB6, VirB8, VirB11, VirD2, and VirE2) were only detected after cell growth below 26 degrees C. Significant levels of class III proteins (VirB3 and VirD4) were only detected at 20 degrees C and not at higher temperatures. Shift of virulence-induced agrobacteria from 20 to 28 or 37 degrees C had no immediate effect on cell-bound T pili or on stability of most virulence proteins. However, the temperature shift caused a rapid decrease in the amount of cell-bound VirB3 and VirD4, and VirB4 and VirB11 levels decreased next. To assess whether destabilization of virulence proteins constitutes a general phenomenon, levels of virulence proteins and of extracellular T pili were monitored in different A. tumefaciens and Agrobacterium vitis strains grown at 20 and 28 degrees C. Levels of many virulence proteins were strongly reduced at 28 degrees C compared to 20 degrees C, and T-pilus assembly did not occur in all strains except "temperature-resistant" Ach5 and Chry5. Virulence protein levels correlated well with bacterial virulence at elevated temperature, suggesting that degradation of a limited set of virulence proteins accounts for the temperature sensitivity of gene transfer to plants.

VirB6 is required for stabilization of VirB5 and VirB3 and formation of VirB7 homodimers in Agrobacterium tumefaciens.

VirB6 from Agrobacterium tumefaciens is an essential component of the type IV secretion machinery for T pilus formation and genetic transformation of plants. Due to its predicted topology as a polytopic inner membrane protein, it was proposed to form the transport pore for cell-to-cell transfer of genetic material and proteinaceous virulence factors. Here, we show that the absence of VirB6 leads to reduced cellular levels of VirB5 and VirB3, which were proposed to assist T pilus formation as minor component(s) or assembly factor(s), respectively. Overexpression of virB6 in trans restored levels of cell-bound and T pilus-associated VirB5 to wild type but did not restore VirB3 levels. Thus, VirB6 has a stabilizing effect on VirB5 accumulation, thereby regulating T pilus assembly. In the absence of VirB6, cell-bound VirB7 monomers and VirB7-VirB9 heterodimers were reduced and VirB7 homodimer formation was abolished. This effect could not be restored by expression of VirB6 in trans. Expression of TraD, a component of the transfer machinery of the IncN plasmid pKM101, with significant sequence similarity to VirB6, restored neither protein levels nor bacterial virulence but partly permitted T pilus formation in a virB6 deletion strain. VirB6 may therefore regulate T pilus formation by direct interaction with VirB5, and wild-type levels of VirB3 and VirB7 homodimers are not required.

Die Gefangene Gottes : Roman

von Schalom Asch. Dt. von Siegfried Schmitz

The importance of socio-cultural factors on sports behaviour of adolescents and young adults in Switzerland – a conceptualisation on the basis of the habitus-approach

Sport participation has often been the topic in sports science and it could be shown that in Europe the population of northern and western countries are more often physically active than southern and eastern countries (European Commission, 2014). In Switzerland the physical activity of the Swiss population also differs between the linguistic regions. The German speaking population is more often physically active than the French or Italian speaking part (Stamm & Lamprecht, 2008). To explain the differences in sport participation structural and cultural factors have been discussed. Because within a country homogenous structural conditions can be assumed, the aim of this study is to analyse how socio-cultural factors correlate with sport participation of adolescents and young adults. In order to analyse this research question, Bourdieu’s concept of habitus (1984) has been used as theoretical background. This sport-related concept of habitus considers cultural determined values, the attribution of meaning and patterns of action which is socially determined and have an influence on individual actions and therefore also on the sport practise. On this basis, a qualitative study including guideline-based interviews with German (n=5) and French (n=3) speaking adolescents and young adults at the age of 16 to 24 (M=21.4) were held in two different linguistic regions of Switzerland. To analyse the interviews the documentary method was applied (Bohnsack, 2010). Initial findings reveal that there are different sport related values, attributions of meanings and patterns of action also called framework of orientations concerning topics like body, health and leisure which correlate with the habitual sports practise in the two different linguistic regions. This study illustrates that the habitus is culturally shaped and that it could help to understand the meaning of socio-cultural factors for sport participation.

Das Recht der israelitischen Religionsgemeinschaft des Großherzogtums Baden

von Siegfried Wolff

Magabuk nen mags

Andersen. Lovepolam fa Lederer Siegfried

Von den Vätern

Schalom Asch. Hrsg. von Siegfried Schmitz