Helical ultrastructure of the L-ENA spore aggregation factor of a Bacillus paranthracis foodborne outbreak strain.

In pathogenic Bacillota, spores can form an infectious particle and can take up a central role in the environmental persistence and dissemination of disease. A poorly understood aspect of spore-mediated infection is the fibrous structures or 'endospore appendages' (ENAs) that have been seen to decorate the spores of pathogenic Bacilli and Clostridia. Current methodological approaches are opening a window on these long enigmatic structures.

Replication Region Analysis Reveals Non-lambdoid Shiga Toxin Converting Bacteriophages.

Shiga toxin is the major virulence factor of enterohemorrhagic (EHEC), and the gene encoding it is carried within the genome of Shiga toxin-converting phages (Stx phages). Numerous Stx phages have been sequenced to gain a better understanding of their contribution to the virulence potential of EHEC. The Stx phages are classified into the lambdoid phage family based on similarities in lifestyle, gene arrangement, and nucleotide sequence to the lambda phages.

Antibiotic residues in final effluents of European wastewater treatment plants and their impact on the aquatic environment.

A comprehensive monitoring of a broad set of antibiotics in the final effluent of wastewater treatment plants (WWTPs) of 7 European countries (Portugal, Spain, Ireland, Cyprus, Germany, Finland, and Norway) was carried out in two consecutive years (2015 and 2016). This is the first study of this kind performed at an international level. Within the 53 antibiotics monitored 17 were detected at least once in the final effluent of the WWTPs, i.

Importance of Individual Germination Receptor Subunits in the Cooperative Function between GerA and Ynd.

Germination of spores is triggered by the binding of specific nutrients to germinant receptors (GRs) located in the spore's inner membrane. The GRs typically consist of A, B, and C subunits, encoded by tricistronic operons. The genome contains the family operons , , and In contrast to the ABC(D) organization that characterizes operons of many species, genomes contain a pentacistronic operon comprising the , , , , and genes encoding A, B, B, C, and B GR subunits, respectively (subscripts indicate paralogs).

Diversity and antibiotic resistance among Escherichia coli populations in hospital and community wastewater compared to wastewater at the receiving urban treatment plant.

Bacterial diversity and antimicrobial resistance patterns among the indicator organism Escherichia coli were monitored in wastewater samples collected over one year from a hospital (HW), a community (CW) and the receiving urban (UW) wastewater treatment plant (WWTP). We compared levels of antibiotic resistance in the different types of wastewater, and identified whether resistant strains were endemic in the wastewater system. If so, implementation of local treatment at certain resistance hotspots (e.

The Cooperative and Interdependent Roles of GerA, GerK, and Ynd in Germination of Bacillus licheniformis Spores.

Unlabelled: When nutrients are scarce, Bacillus species form metabolically dormant and extremely resistant spores that enable survival over long periods of time under conditions not permitting growth. The presence of specific nutrients triggers spore germination through interaction with germinant receptors located in the spore's inner membrane. Bacillus licheniformis is a biotechnologically important species, but it is also associated with food spoilage and food-borne disease.

The highly virulent 2006 Norwegian EHEC O103:H25 outbreak strain is related to the 2011 German O104:H4 outbreak strain.

In 2006, a severe foodborne EHEC outbreak occured in Norway. Seventeen cases were recorded and the HUS frequency was 60%. The causative strain, Esherichia coli O103:H25, is considered to be particularly virulent.

An outbreak of Escherichia coli O103:H25 - bacteriological investigations and genotyping of isolates from food.

During the spring of 2006, a national disease outbreak caused by Shiga toxin-producing Escherichia coli (STEC) O103:H25 was investigated in Norway. At the time of the outbreak the Norwegian School of Veterinary Science was the national reference laboratory for E. coli O157 in food, and the microbiological investigations to identify the food source were performed there.

Transmission and long-term stability of compensated CD8 escape mutations.

Human immunodeficiency virus effectively evades CD8(+) T-cell responses through the development of CD8 escape mutations. Recent reports documenting reversion of transmitted mutations and the impact of specific escape mutations upon viral replication suggest that complex forces limit the accumulation of CD8 escape mutations at the population level. However, the presence of compensatory mutations capable of alleviating the impact of CD8 escape mutations on replication capacity may enable their persistence in an HLA-mismatched host.

Food poisoning potential of Bacillus cereus strains from Norwegian dairies.

Characteristics concerning diarrhoeal potential were investigated in B. cereus dairy strains. The thirty-nine strains, isolated from whipping cream, were tested for cytotoxicity after culturing at human body temperature as well as 25 degrees C and 32 degrees C.

Fluctuations of functionally distinct CD8+ T-cell clonotypes demonstrate flexibility of the HIV-specific TCR repertoire.

T-cell receptor (TCR) diversity of virus-specific CD8+ T cells likely helps prevent escape mutations in chronic viral infections. To understand the dynamics of the virus-specific T cells in more detail, we followed the evolution of the TCR repertoire specific for a dominant HLA-B*08-restricted epitope in Nef (FLKEKGGL) in a cohort of subjects infected with HIV. Epitope-specific CD8+ T cells used structurally diverse TCR repertoires, with different TCRbeta variable regions and with high amino acid diversity within antigen recognition sites.

Selective escape from CD8+ T-cell responses represents a major driving force of human immunodeficiency virus type 1 (HIV-1) sequence diversity and reveals constraints on HIV-1 evolution.

The sequence diversity of human immunodeficiency virus type 1 (HIV-1) represents a major obstacle to the development of an effective vaccine, yet the forces impacting the evolution of this pathogen remain unclear. To address this issue we assessed the relationship between genome-wide viral evolution and adaptive CD8+ T-cell responses in four clade B virus-infected patients studied longitudinally for as long as 5 years after acute infection. Of the 98 amino acid mutations identified in nonenvelope antigens, 53% were associated with detectable CD8+ T-cell responses, indicative of positive selective immune pressures.

Limited sequence evolution within persistently targeted CD8 epitopes in chronic human immunodeficiency virus type 1 infection.

Studies in acute human immunodeficiency virus type 1 (HIV-1) infection indicate viral evolution under CD8 T-cell immune selection pressure, but the effects of ongoing immune pressure on epitope evolution during chronic infection are not well described. In this study, we performed a detailed longitudinal analysis of viral sequence variation within persistently targeted cytotoxic T-lymphocyte (CTL) epitopes in two HIV-1-infected persons during 6 years of persistent viremia. Responses were quantitated using freshly isolated peripheral blood lymphocytes in direct lytic assays as well as by gamma interferon (IFN-gamma) Elispot assays on cryopreserved cells.

Simultaneous measurement of metabolic and acoustic power and the efficiency of sound production in two mole cricket species (Orthoptera: Gryllotalpidae).

We here report the first simultaneous measurement of metabolic cost of calling, acoustic power and efficiency of sound production in animals--the mole crickets Scapteriscus borellii and S. vicinus (Gryllotalpidae). We measured O(2) consumption, CO(2) production and acoustic power as the crickets called from their burrows in an open room.

Selection, transmission, and reversion of an antigen-processing cytotoxic T-lymphocyte escape mutation in human immunodeficiency virus type 1 infection.

Numerous studies now support that human immunodeficiency virus type 1 (HIV-1) evolution is influenced by immune selection pressure, with population studies showing an association between specific HLA alleles and mutations within defined cytotoxic T-lymphocyte epitopes. Here we combine sequence data and functional studies of CD8 T-cell responses to demonstrate that allele-specific immune pressures also select for mutations flanking CD8 epitopes that impair antigen processing. In persons expressing HLA-A3, we demonstrate consistent selection for a mutation in a C-terminal flanking residue of the normally immunodominant Gag KK9 epitope that prevents its processing and presentation, resulting in a rapid decline in the CD8 T-cell response.

Fine specificity and cross-clade reactivity of HIV type 1 Gag-specific CD4+ T cells.

Despite growing evidence that HIV-1-specific CD4(+) T helper (Th) cells may play a role in the control of viremia, discrete Th cell epitopes remain poorly defined. Furthermore, it is not known whether Th cell responses generated using vaccines based on clade B virus sequences will elicit immune responses that are effective in regions of the world where non-clade B viruses predominate. To address these issues we isolated CD4(+) T cell clones from individuals with vigorous HIV-1-specific Th cell responses and identified the minimum epitopes recognized.

Enhanced detection of human immunodeficiency virus type 1-specific T-cell responses to highly variable regions by using peptides based on autologous virus sequences.

The antigenic diversity of human immunodeficiency virus type 1 (HIV-1) represents a significant challenge for vaccine design as well as the comprehensive assessment of HIV-1-specific immune responses in infected persons. In this study we assessed the impact of antigen variability on the characterization of HIV-1-specific T-cell responses by using an HIV-1 database to determine the sequence variability at each position in all expressed HIV-1 proteins and a comprehensive data set of CD8 T-cell responses to a reference strain of HIV-1 in infected persons. Gamma interferon Elispot analysis of HIV-1 clade B-specific T-cell responses to 504 overlapping peptides spanning the entire expressed HIV-1 genome derived from 57 infected subjects demonstrated that the average amino acid variability within a peptide (entropy) was inversely correlated to the measured frequency at which the peptide was recognized (P = 6 x 10(-7)).