Monoclonal antibodies targeting different cell wall antigens of group B streptococcus mediate protection in both Fc-dependent and independent manner.

Group B streptococcus remains an important neonatal pathogen in spite of widely adopted intrapartum antibiotic administration; therefore immune prophylaxis for GBS infections is highly warranted. In passive immunization and lethal challenge studies with multiple GBS strains, we characterized the protective effect of rabbit polyclonal and murine monoclonal antibodies specific for four multi-functional cell wall anchored proteins, FbsA, BibA, PilA and PilB. Single specificity rabbit sera or mAbs induced high level, but strain dependent protection, while their combinations resulted in superior and broad efficacy against all GBS strains tested.

Rga is a regulator of adherence and pilus formation in Streptococcus agalactiae.

Streptococcus agalactiae is the leading cause of bacterial sepsis and meningitis in neonates and is also the causative agent of several serious infections in immunocompromised adults. S. agalactiae encounters multiple niches during an infection, suggesting that regulatory mechanisms control the expression of specific virulence factors in this bacterium.

The surface protein Srr-1 of Streptococcus agalactiae binds human keratin 4 and promotes adherence to epithelial HEp-2 cells.

Streptococcus agalactiae is frequently the cause of bacterial sepsis and meningitis in neonates. In addition, it is a commensal bacterium that colonizes the mammalian gastrointestinal tract. During its commensal and pathogenic lifestyles, S.

The transcriptional regulator RovS controls the attachment of Streptococcus agalactiae to human epithelial cells and the expression of virulence genes.

Streptococcus agalactiae is part of the normal flora of the human gastrointestinal tract and also the leading cause of bacterial infections in human newborns and immunocompromised adults. The colonization and infection of different regions within the human host require a regulatory network in S. agalactiae that senses environmental stimuli and controls the formation of specific virulence factors.

Adherence to and invasion of human brain microvascular endothelial cells are promoted by fibrinogen-binding protein FbsA of Streptococcus agalactiae.

Streptococcus agalactiae is a frequent cause of bacterial sepsis and meningitis in neonates. During the course of infection, S. agalactiae colonizes and invades a number of host compartments, thereby interacting with different host tissues.

The fibrinogen receptor FbsA promotes adherence of Streptococcus agalactiae to human epithelial cells.

Streptococcus agalactiae is a major cause of bacterial pneumonia, sepsis, and meningitis in human neonates. During the course of infection, S. agalactiae adheres to a variety of epithelial cells but the underlying mechanisms are only poorly understood.

FbsA, a fibrinogen-binding protein from Streptococcus agalactiae, mediates platelet aggregation.

The bacterium Streptococcus agalactiae is an etiologic agent in the pathogenesis of endocarditis in humans. FbsA, a fibrinogen-binding protein produced by this pathogen, is considered an important virulence factor. In the present study we provide evidence that S agalactiae clinical isolates bearing FbsA attach to fibrinogen and elicit a fibrinogen-dependent aggregation of platelets.

The novel fibrinogen-binding protein FbsB promotes Streptococcus agalactiae invasion into epithelial cells.

Streptococcus agalactiae is a major cause of bacterial sepsis and meningitis in human newborns. The interaction of S. agalactiae with host proteins and the entry into host cells thereby represent important virulence traits of these bacteria.

Relevance of peptide uptake systems to the physiology and virulence of Streptococcus agalactiae.

Streptococcus agalactiae is a major cause of invasive infections in human newborns. To satisfy its growth requirements, S. agalactiae takes up 9 of the 20 proteinogenic amino acids from the environment.

Acetate metabolism and its regulation in Corynebacterium glutamicum.

The amino acid producing Corynebacterium glutamicum grows aerobically on a variety of carbohydrates and organic acids as single or combined sources of carbon and energy. Among the substrates metabolized are glucose and acetate which both can also serve as substrates for amino acid production. Based on biochemical, genetic and regulatory studies and on quantitative determination of metabolic fluxes during utilization of acetate and/or glucose, this review summarizes the present knowledge on the different steps of the fundamental pathways of acetate utilization in C.

Analysis of RogB-controlled virulence mechanisms and gene repression in Streptococcus agalactiae.

Streptococcus agalactiae is the leading cause of bacterial sepsis and meningitis in neonates and also the causative agent of different serious infections in immunocompromised adults. The wide range of diseases that are caused by S. agalactiae suggests regulatory mechanisms that control the formation of specific virulence factors in these bacteria.

Functional analysis of a PcsB-deficient mutant of group B streptococcus.

Group B streptococcus (GBS) is the major cause of bacterial sepsis and meningitis in neonates and poses a significant threat to parturient women. Recently, we identified in GBS the polypeptide PcsB, which is a protein required for cell separation of GBS, and which is also involved in the antibiotic sensitivity of these bacteria. In the present study, the introduction of the pcsB-carrying plasmid pATpcsB into the PcsB-deficient GBS mutant Sep1 restored the phenotype and the antibiotic susceptibility of this strain to that of the GBS wild-type.

A fibrinogen receptor from group B Streptococcus interacts with fibrinogen by repetitive units with novel ligand binding sites.

Group B Streptococcus (GBS) is a frequent cause of bacterial sepsis and meningitis in neonates. During the course of infection, GBS colonizes and invades a number of host compartments, thereby interacting with different host proteins. In the present report, we describe the isolation of the fbsA gene, which encodes a fibrinogen receptor from GBS.

Influence of proteins Bsp and FemH on cell shape and peptidoglycan composition in group B streptococcus.

Group B streptococcus (GBS) is surrounded by a capsule. However, little is known about peptidoglycan metabolism in these bacteria. In the present study, a 65 kDa protein was isolated from the culture supernatant of GBS and N-terminally sequenced, permitting isolation of the corresponding gene, termed bsp.

Identification and characterization of a novel secreted immunoglobulin binding protein from group A streptococcus.

Immunoglobulin binding proteins are one of several pathogenicity factors which have been associated with invasive disease caused by group A streptococci. The surface-bound M and M-like proteins of Streptococcus pyogenes are the most characterized of these immunoglobulin binding proteins, and in most cases they bind only a single antibody class. Here we report the identification of a novel non-M-type secreted protein, designated SibA (for secreted immunoglobulin binding protein from group A streptococcus), which binds all immunoglobulin G (IgG) subclasses, the Fc and Fab fragments, and also IgA and IgM.

Identification and molecular analysis of PcsB, a protein required for cell wall separation of group B streptococcus.

Group B streptococcus (GBS) is the leading cause of bacterial sepsis and meningitis in neonates. N-terminal sequencing of major proteins in the culture supernatant of a clinical isolate of GBS identified a protein of about 50 kDa which could be detected in all of 27 clinical isolates tested. The corresponding gene, designated pcsB, was isolated from a GBS cosmid library and subsequently sequenced.

Enterohemorrhagic Escherichia coli O157:H7 produces Tir, which is translocated to the host cell membrane but is not tyrosine phosphorylated.

Intimate attachment to the host cell leading to the formation of attaching and effacing (A/E) lesions is an essential feature of enterohemorrhagic Escherichia coli (EHEC) O157:H7 pathogenesis. In a related pathogen, enteropathogenic E. coli (EPEC), this activity is dependent upon translocation of the intimin receptor, Tir, which becomes tyrosine phosphorylated within the host cell membrane.

Cloning, sequence analysis, expression and inactivation of the Corynebacterium glutamicum pta-ack operon encoding phosphotransacetylase and acetate kinase.

The Corynebacterium glutamicum ack and pta genes encoding the acetate-activating enzymes acetate kinase and phosphotransacetylase were isolated, subcloned on a plasmid and re-introduced into Corynebacterium glutamicum. Relative to the wild-type, the recombinant strains showed about tenfold higher specific activities of both enzymes. Sequence analysis of a 3657 bp DNA fragment revealed that the ack and pta genes are contiguous in the corynebacterial chromosome, with pta upstream and the last nucleotide of the pta stop codon (TAA) overlapping the first of the ack start codon (ATG).

Enteropathogenic E. coli (EPEC) transfers its receptor for intimate adherence into mammalian cells.

Enteropathogenic E. coli (EPEC) belongs to a group of bacterial pathogens that induce epithelial cell actin rearrangements resulting in pedestal formation beneath adherent bacteria. This requires the secretion of specific virulence proteins needed for signal transduction and intimate adherence.

Regulation of acetate metabolism in Corynebacterium glutamicum: transcriptional control of the isocitrate lyase and malate synthase genes.

In the amino-acid-producing microorganism Corynebacterium glutamicum, the specific activities of the acetate-activating enzymes acetate kinase and phosphotransacetylase and those of the glyoxylate cycle enzymes isocitrate lyase and malate synthase were found to be high when the cells were grown on acetate (0.8, 2.9, 2.

Enteropathogenic E. coli exploitation of host epithelial cells.

Enteropathogenic E. coli (EPEC) is a leading cause of neonatal diarrhea worldwide. These organisms adhere to the intestinal cell surface, causing rearrangement in the epithelial cell surface and underlying cytoskeleton, resulting in a structure termed an attaching/effacing (A/E) lesion.

A pathogenic bacterium triggers epithelial signals to form a functional bacterial receptor that mediates actin pseudopod formation.

Enteropathogenic E. coli (EPEC) belongs to a group of bacterial pathogens that induce actin accumulation beneath adherent bacteria. We found that EPEC adherence to epithelial cells mediates the formation of fingerlike pseudopods (up to 10 microm) beneath bacteria.

Malate synthase from Corynebacterium glutamicum: sequence analysis of the gene and biochemical characterization of the enzyme.

Malate synthase is one of the key enzymes of the glyoxylate cycle and is essential for growth on acetate as sole carbon source. The aceB gene from Corynebacterium glutamicum, encoding malate synthase, was isolated, subcloned and expressed in Escherichia coli and C. glutamicum.

Characterization of the isocitrate lyase gene from Corynebacterium glutamicum and biochemical analysis of the enzyme.

Isocitrate lyase is a key enzyme in the glyoxylate cycle and is essential as an anaplerotic enzyme for growth on acetate as a carbon source. It is assumed to be of major importance in carbon flux control in the amino acid-producing organism Corynebacterium glutamicum. In crude extracts of C.

Stable Expression of hom-1-thrB in Corynebacterium glutamicum and Its Effect on the Carbon Flux to Threonine and Related Amino Acids.

The hom-1-thrB operon encodes homoserine dehydrogenase resistant to feedback inhibition by L-threonine and homoserine kinase. Stable expression of this operon has not yet been attained in different Corynebacterium glutamicum strains. We studied the use of chromosomal integration and of a low-copy-number vector for moderate expression of the hom-1-thrB operon to enable an analysis of the physiological consequences of its expression in C.