PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “BACTERIAL PROTEINS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources
PubMed2006

Bacterial protein toxins and lipids: pore formation or toxin entry into cells.

Lipids are hydrophobic molecules which play critical functions in cells, in particular, they are essential constituents of membranes, whereas bacterial toxins are mainly hydrophilic proteins. All bacterial toxins interact first with their target cells by recognizing a surface receptor, which is either a lipid or a lipid derivative, or another compound but in a lipid environment. Most bacterial toxins are PFTs (pore-forming toxins) which oligomerize and insert into the lipid bilayer. A common mechanism of action involves the formation of a beta-barrel structure, resulting from the assembly of individual beta-hairpin(s) from individual monomers. An essential step for intracellular active toxins is to translocate their enzymatic part into the cytosol. Some toxins use a translocation mechanism based on pore formation similar to that of PFTs, others undergo a yet unclear 'chaperone' process.

Bacterial Toxins↗
PubMed1997

Type III secretion systems: machines to deliver bacterial proteins into eukaryotic cells?

Type III secretion systems in certain bacterial pathogens are induced upon contact with host cells and directly deliver virulence proteins into the host cell cytosol. The increasing number of Gram-negative bacterial pathogens discovered to encode type III secretion systems raises interesting questions. Are type III systems generic machines that deliver virulence proteins into host cells? Is contact with host cells a common regulatory cue for type III systems?

Bacterial Proteins↗
PubMed2005

The structure of the bacterial protein translocation complex SecYEG.

Proteins destined for secretion, membrane insertion or organellar import contain signal sequences that direct them to the membrane. Once there, transport machines receive and translocate them appropriately across or into the membrane. The related SecY and Sec61 protein translocation complexes are ubiquitous components of machines that are essential for protein transport. They co-operate with various partners such that the substrate polypeptide is pulled or pushed through the membrane by post- or co-translational mechanisms. In bacteria and archaea, the SecY complex (SecYEG/SecYEbeta) is a heterotrimer, which associates with ribosomes so that the polypeptide is threaded through the channel during its synthesis. Bacteria possess an additional pathway, whereby the newly synthesized substrate protein is maintained in an unfolded conformation and is engaged by the ATPase SecA and delivered to the translocon. Recent medium- (cryo-electron microscopy) and high-resolution (X-ray) structures of the Sec complex have dramatically increased our understanding about how proteins pass through membranes, but have posed a number of new questions. The Sec complex is active as an oligomer, but the structure indicates that the protein-conducting channel is formed by a monomer of SecYEG. Structures of the membrane-bound dimer of Escherichia coli SecYEG and the detergent-solubilized monomer of Methanococcus jannaschii SecYEbeta will be described and discussed in the context of the mechanism that underlies protein secretion and membrane insertion.

Bacterial Proteins↗
PubMed2000

Detection of viral and bacterial protein in endomyocardial biopsies of patients with inflammatory heart muscle disease?

The development of highly sensitive molecular biological methods such as in-situ hybridization and polymerase chain reaction (PCR) made it possible to detect viral/bacterial nucleic acid in human endomyocardial biopsies. However, only a few investigations addressed the problem of latent persistence of viral and bacterial genome and the detection of the corresponding proteins, which could have important consequences for the clinical course of the disease. The purpose of this study was to determine whether protein of various viruses (adenovirus, enterovirus, cytomegalovirus, influenza A and B virus, herpes simplex virus 1 and 2) and bacteria (chlamydia pneumonia) can be detected in endomyocardial biopsies of patients with myocarditis and dilated cardiomyopathy with and without inflammation by use of an immunofluorescence assay and to compare the frequency of its detection with the results of PCR, immunohistology and serology. Thirty-nine patients with myocarditis and dilated cardiomyopathy with and without inflammation were examined by a direct immunofluorescence assay using the endomyocardial biopsy as antigen. Each of the samples was additionally studied by immunohistological methods and PCR for the detection of infiltrating cells and the genome of cardiotropic viruses or bacteria. Fourteen of patients were considered to have myocarditis (group 1), 9 dilated cardiomyopathy with inflammation (group 2), 10 dilated cardiomyopathy (group 3), 6 to have no myocarditis or dilated cardiomyopathy (group 4). Using a direct immunofluorescence assay we could show only that 1 patient without histological myocarditis or dilated cardiomyopathy (group 4) was positive for influenza B and chlamydia pneumonia antigens in the endomyocardial biopsy. In addition we have determined influenza B-specific antibodies, such as IgG (marginal titer) and IgA (high titer) and chlamydia pneumonia-specific antibodies, such as IgG (marginal titer) in serum of this patient. A second patient with dilated cardiomyopathy was found to be positive for protein of chlamydia pneumonia, who was shown to have chlamydia pneumonia-specific antibodies, such as IgG (high titer) in serum. There was no correlation with PCR results, but good correlation with influenza B and chlamydia pneumonia-specific antibodies in sera of these patients. In this investigation we have determined viral/bacterial-specific antibodies using serological methods and proteins of these agents using immunoflourescence. Despite the detection of virus or bacteria-specific antibodies in the sera and detection of viral and/or bacterial protein in the biopsies of some of the patients viral and/or bacterial genome was not found in the biopsy. This may be explained by the focal character of myocarditis and sampling error, because for technical reasons we use different biopsies for immunohistochemical and molecular biological investigations.

Adult↗
PubMed1991

A convenient gel holder for preparative electrophoretic separation of aggregated bacterial proteins.

A simple custom-made gel holder for preparative SDS-PAGE to separate aggregated bacterial antigens is described. The gel holder fits easily into commercially available gel electrophoresis apparatus and proteins or peptides are collected in a stream of distilled water through a channel in the gel. The performance of the device was illustrated by the successful separation and purification of fragments of aggregated Streptococcus equi M protein and of Erysipelothrix rhusiopathiae protective antigens. Yields of up to 1.2 mg per run were obtained. The purified proteins retained immunological reactivity and were of sufficient purity for amino acid compositional and sequence analysis.

Antigens, Bacterial↗
PubMed1997

Dynamic, mitotic-like behavior of a bacterial protein required for accurate chromosome partitioning.

The Bacillus subtilis spo0J gene is required for accurate chromosome partitioning during growth and sporulation. We have characterized the subcellular localization of Spo0J protein by immunofluorescence and, in living cells, by use of a spo0J-gfp fusion. We show that the Spo0J protein forms discrete stable foci usually located close to the cell poles. The foci replicate in concert with the initiation of new rounds of DNA replication, after which the daughter foci migrate apart inside the cell. This migration is independent of cell length extension, and presumably serves to direct the daughter chromosomes toward opposite poles of the cell, ready for division. During sporulation, the foci move to the extreme poles of the cell, where they function to position the oriC region of the chromosome ready for polar septation. These observations provide strong evidence for the existence of a dynamic, mitotic-like apparatus responsible for chromosome partitioning in bacteria.

Amino Acid Sequence↗
PubMed1996

Determination of bacterial protein profiles by matrix-assisted laser desorption/ionization mass spectrometry with high-performance liquid chromatography.

A rapid method for profiling bacterial and cellular proteins has been developed using a combination of capillary high-performance liquid chromatography separation followed by (MALDI-MS) matrix-assisted laser desorption/ionization mass spectrometric analysis. In this method, bacteria are sonicated, the cell walls broken, and the water-soluble proteins precipitated for analysis. The proteins are separated by capillary liquid chromatography and detected on-line by a UV absorption detector. The eluents are then collected for off-line analysis by MALDI-MS. Using this method, it is demonstrated that bacteria can be discriminated based upon their protein profiles to the species level with only pmol level detection of proteins. It has also proved to be a fast and accurate means for monitoring the expression of Hsp27 in an insect cell system.

Animals↗