The cell wall-associated serine protease PrtA: a highly conserved virulence factor of Streptococcus pneumoniae

The surface-associated subtilisin-like serine protease PrtA was identified by screening a genomic expression library from Streptococcus pneumoniae using a convalescent-phase serum. In Western blot analysis two forms of PrtA were detected in whole cell lysate and a truncated form only in culture supernatant suggesting that PrtA is produced as a precursor protein, translocated to the cell surface, truncated, and released into the surroundings. A 5' fragment of the gene was found highly conserved among 78 pneumococcal isolates of clinical relevance. Immunogenicity of PrtA, limited genetic variation, and the involvement in pneumococcal virulence demonstrated in in vivo experiments might identify PrtA as a promising candidate for a protein based vaccine.     

The diversity of fungi in aerobic sewage granules assessed by 18S rRNA gene and ITS sequence analyses

Aerobic sewage granules are dense, spherical biofilms, regarded as a useful and promising tool in wastewater treatment processes. Recent studies revealed that fungi can be implemented in biofilm formation. This study attempts to uncover the fungal diversity in aerobic granules by sequence analysis of the 18S and 5.8S rRNA genes and the internal transcribed spacer regions. For this purpose, appropriate PCR and sequencing primer sets were selected and an improved DNA isolation protocol was used. The sequences of 41 isolates were assigned to the taxonomic groups Pleosporaceae, Xylariales, Theleobolaceae, Claviceps, Aureobasidium, Candida boleticola , and Tremellomycetes within the fungi. It turned out that the fungal community composition in granules depended on the wastewater type and the phase of granule development.     

History or ecology? Substrate type as a major driver of patial genetic structure in Alpine plants

Climatic history and ecology are considered the most important factors moulding the spatial pattern of genetic diversity. With the advent of molecular markers, species' historical fates have been widely explored. However, it has remained speculative what role ecological factors have played in shaping spatial genetic structures within species. With an unprecedented, dense large-scale sampling and genome-screening, we tested how ecological factors have influenced the spatial genetic structures in Alpine plants. Here, we show that species growing on similar substrate types, largely determined by the nature of bedrock, displayed highly congruent spatial genetic structures. As the heterogeneous and disjunctive distribution of bedrock types in the Alps, decisive for refugial survival during the ice ages, is temporally stable, concerted post-glacial migration routes emerged. Our multispecies study demonstrates the relevance of particular ecological factors in shaping genetic patterns, which should be considered when modelling species projective distributions under climate change scenarios.     

Streptococcus pyogenes collagen type I-binding Cpa surface protein. Expression profile, binding characteristics, biological functions, and potential clinical impact

The Streptococcus pyogenes collagen type I-binding protein Cpa (collagen-binding protein of group A streptococci) expressed by 28 serotypes of group A streptococci has been extensively characterized at the gene and protein levels. Evidence for three distinct families of cpa genes was found, all of which shared a common sequence encoding a 60-amino acid domain that accounted for selective binding to type I collagen. Surface plasmon resonance-based affinity measurements and functional studies indicated that the expression of Cpa was consistent with an attachment role for bacteria to tissue containing collagen type I. A cpa mutant displayed a significantly decreased internalization rate when incubated with HEp-2 cells but had no effect on the host cell viability. By utilizing serum from patients with a positive titer for streptolysin/DNase antibody, an increased anti-Cpa antibody titer was noted for patients with a clinical history of arthritis or osteomyelitis. Taken together, these results suggest Cpa may be a relevant matrix adhesin contributing to the pathogenesis of S. pyogenes infection of bones and joints.     

Localization of vicilin genes via polymerase chain reaction on microisolated field bean chromosomes

A new technique is reported for the physical mapping of low copy DNA sequences on plant chromosomes. Individual chromosomes were microisolated and their DNA used as the target for the polymerase chain reaction in order to identify the chromosome carrying a specific gene sequence. The use of defined translocation chromosomes further refined the resolution of the method to a subchromosomal level. To demonstrate the applicability of the procedure genes have been localized coding for vicilin seed storage proteins on the field bean Vicia faba L. in a region which includes the centromere and the proximal parts of the short and the long arms of chromosome II.     

Human Myelin/Oligodendrocyte Glycoprotein: A New Member of the L2/HNK-1 Family

Abstract— Myelin/oligodendrocyte glycoprotein (MOG) is a quantitatively minor component of CMS myelin. In this study, human MOG was found to express the L2/HNK-1 epitope on N-linked oligosaccharide structures. This carbohydrate epitope has been found previously in three other characterized human myelin glycoproteins: the my-elin-associated glycoprotein, P₀, and the oligodendrocyte-myelin glycoprotein. It seems, therefore, that the L2/HNK-1 epitope is expressed frequently in human myelin glycoproteins. Serial lectin affinity chromatography of ¹⁴C-glycopeptides indicated that MOG N -oligosaccharide structures are mainly of the complex type, accounting for 77.8% of total radioactivity. In contrast with myelin-asso-ciated glycoprotein and P₀, which express the L2/HNK-1 epitope on fucosylated structures, in MOG the epitope was detected on all glycopeptide fractions obtained by serial lectin affinity chromatography, although a preferential expression of the L2/HNK-1 epitope was observed on fucosylated structures. Finally, the data indicated that, as for other human myelin glycoproteins, only a subpopulation of MOG molecules expresses the L2/HNK-1 epitope.     

Comparison of the N-Linked Oligosaccharide Structures of the Two Major Human Myelin Glycoproteins MAG and P0: Assessment and Relative Occurrence of Oligosaccharide Structures by Serial Lectin Affinity Chromatography of 14C-Glycopeptides

The N-linked oligosaccharide structures of human myelin-associated glycoprotein (MAG) and P0 have been characterized by serial lectin affinity chromatography (SLAC) of 14C-glycopeptides. 14C-Glycopeptides were prepared from purified MAG derivative and P0 by extensive proteolytic digestion and N-14C-acetylation. Assuming that all the 14C-glycopeptides were radiolabelled to the same specific radioactivity, the relative occurrence of the oligosaccharide structures was correlated to the amount of incorporated radioactivity. Sixteen and 15 fractions were generated by SLAC of MAG and P0 14C-glycopeptides, respectively. Despite this tremendous structural heterogeneity, the oligosaccharide "fingerprints" of MAG and P0 obtained by SLAC displayed similarities: (a) of the three types of N-linked oligosaccharides, the complex type accounted for 80.4% and 94.9% of MAG and P0 radioactivity, respectively; (b) biantennary complex oligosaccharides were the major structures present on MAG and P0; (c) approximately 60% of MAG and P0 oligosaccharides possessed a bisecting N-acetylglucosamine residue; and (d) large amounts of oligosaccharides with an alpha(1-6)fucose residue were found in both MAG and P0 and, noticeably, approximately 25% of the tri- and/or tetraantennary and approximately 90% of the bisected biantennary oligosaccharides of both glycoproteins contained alpha(1-6)fucose residues in the core. This study demonstrates that MAG and P0, both belonging to the immunoglobulin superfamily, display structural similarities in their N-linked oligosaccharide contents.