Surface Proteins Of Bacteria Research Articles

The Critical Role of Intracellular Bacterial Communities in Uncomplicated Recurrent Urinary Cystitis: A Comprehensive Review of Detection Methods and Diagnostic Potential.

Urinary tract infections (UTIs) are among the most common bacterial infections worldwide and are particularly prevalent in women. Recurrent UTIs significantly diminish quality of life due to their symptoms and frequent relapses. Patients often experience immediate relapse following slightly strenuous activities or intense psychological stress. In this review, we explore why infections persist despite the advent of various treatments and suggest strategies to manage recurrent cystitis by targeting the mechanisms of adhesion and infection. Vitamin D levels and the expression of neutrophil gelatinase-associated lipocalin are linked to the recurrence of UTIs. During a UTI, bacteria employ adhesins to invade the urinary tract, adhere to urothelial cells, and then penetrate these cells, where they rapidly multiply to establish intracellular bacterial communities. Bacteria can also form quiescent intracellular reservoirs that escape immune responses and antibiotic treatments, leading to recurrence under certain conditions. The surface proteins of bacteria and D-mannose are crucial in the adhesion of bacteria to the urothelium. Understanding these processes provides valuable insights into potential therapeutic approaches that focus on preventing bacterial attachment and cluster formation. By disrupting the ability of bacteria to adhere to and form clusters on cells, we can better manage recurrent UTIs and improve patient outcomes.

Investigation of Cell Envelope‐Associated Proteins in Rumen Methanogens as Targets for Understanding Host‐Microbe Interactions

The rumen microbiota is complex and almost totally composed of anaerobic organisms, including methanogenic archaea (methanogens). The latter occupy a unique niche in the rumen, using hydrogen, formate and methyl compounds to produce methane.Many of the proteins predicted from analysis of genome sequences of rumen‐dwelling methanogens, in particular cell envelope‐associated proteins, have no known biological function. To elucidate the role of these proteins in methanogen activity in the rumen and in the interaction of these archaea with other ruminal microbes, we have produced antibodies against selected methanogen proteins. The proteins were expressed in a standard bacterial expression system. An important first step was to determine if recombinantly produced proteins can generate antibodies that bind and recognise the native methanogens proteins.Bioinformatic analysis of the genome of Methanobrevibacter ruminantium M1 identified suitable cell surface‐located proteins for the studies. Predicted extracellular domains of these proteins were synthesised in Escherichia coli and circular dichroism analysis was performed to check that each recombinant protein had an ordered structure. Antibodies were produced against each recombinant protein and used in ELISA and Western blotting on lysates and membrane protein enriched fractions prepared from M1 cells. Proteins in the fractions were further separated by 2D gel electrophoresis and specific binding of the antibodies to the native targets was confirmed by LC‐MS/MS. Binding of the antibodies to methanogen cells was demonstrated using ELISA and flow cytometry.Our results to date suggest that expression of some of the cell surface proteins in bacteria produced recombinant proteins that sufficiently mimic the native proteins, with cross‐reactivity of antibodies to methanogen cell extracts. Our immunological studies, together with new information on gene expression from transcriptomic analysis of M1 in cultures, is being used to further understand the biological function of methanogen cell surface proteins and how methanogens interact with other microbes in the rumen.Support or Funding InformationThis research was funded jointly by Pastoral Greenhouse Gas Research Consortium (PGgRc) and New Zealand Agricultural Greenhouse Gas Research Centre (NZAGRC)

Catching a SPY: Using the SpyCatcher-SpyTag and Related Systems for Labeling and Localizing Bacterial Proteins.

The SpyCatcher-SpyTag system was developed seven years ago as a method for protein ligation. It is based on a modified domain from a Streptococcus pyogenes surface protein (SpyCatcher), which recognizes a cognate 13-amino-acid peptide (SpyTag). Upon recognition, the two form a covalent isopeptide bond between the side chains of a lysine in SpyCatcher and an aspartate in SpyTag. This technology has been used, among other applications, to create covalently stabilized multi-protein complexes, for modular vaccine production, and to label proteins (e.g., for microscopy). The SpyTag system is versatile as the tag is a short, unfolded peptide that can be genetically fused to exposed positions in target proteins; similarly, SpyCatcher can be fused to reporter proteins such as GFP, and to epitope or purification tags. Additionally, an orthogonal system called SnoopTag-SnoopCatcher has been developed from an S. pneumoniae pilin that can be combined with SpyCatcher-SpyTag to produce protein fusions with multiple components. Furthermore, tripartite applications have been produced from both systems allowing the fusion of two peptides by a separate, catalytically active protein unit, SpyLigase or SnoopLigase. Here, we review the current state of the SpyCatcher-SpyTag and related technologies, with a particular emphasis on their use in vaccine development and in determining outer membrane protein localization and topology of surface proteins in bacteria.

The Streptococcos suis sortases SrtB and SrtF are essential for disease in pigs.

The porcine pathogen Streptococcus suis colonizes the upper respiratory tracts of pigs, potentially causing septicaemia, meningitis and death, thus placing a severe burden on the agricultural industry worldwide. It is also a zoonotic pathogen that is known to cause systemic infections and meningitis in humans. Understanding how S. suis colonizes and interacts with its hosts is relevant for future strategies of drug and vaccine development. As with other Gram-positive bacteria, S. suis utilizes enzymes known as sortases to attach specific proteins bearing cell wall sorting signals to its surface, where they can play a role in host-pathogen interactions. The surface proteins of bacteria are often important in adhesion to and invasion of host cells. In this study, markerless in-frame deletion mutants of the housekeeping sortase srtA and the two pilus-associated sortases, srtB and srtF, were generated and their importance in S. suis infections was investigated. We found that all three of these sortases are essential to disease in pigs, concluding that their cognate-sorted proteins may also be useful in protecting pigs against infection.

Investigating infection processes with a workflow from organic chemistry to biophysics: the combination of metabolic glycoengineering, super-resolution fluorescence imaging and proteomics

Infectious diseases continue to be one of the major threats to public health. In the initial events of infection, glycoproteins of human cells interact with surface proteins of bacteria or viruses, the so-called environmental adhesins. In order to pinpoint the driving forces during infection, it is necessary to study the adhesive properties of human cell surface glycoproteins with regard to their primary amino acid sequence and post-translational modifications. The authors discuss how recent developments in seemingly independent fields of the natural sciences, bio-organic synthesis, biophysical visualization and bioanalysis, open the door for a promising interdisciplinary approach to study human infection processes. The use of special synthesized carbohydrate labels, in combination with new super-resolution imaging approaches, allows access to both mapping and identification of cell surface glycoproteins well below the diffraction limit. The methodology will clarify which surface molecules are involved in bacterial adherence with potential implications for bacterial and viral infection prevention.

An automatic method for identifying surface proteins in bacteria: SLEP

BackgroundBacterial infections represent a global health challenge. The identification of novel antibacterial targets for both therapy and vaccination is needed on a constant basis because resistance continues to spread worldwide at an alarming rate. Even infections that were once easy to treat are becoming difficult or, in some cases, impossible to cure. Ideal targets for both therapy and vaccination are bacterial proteins exposed on the surface of the organism, which are often involved in host-pathogen interaction. Their identification can greatly benefit from technologies such as bioinformatics, proteomics and DNA microarrays.ResultsHere we describe a pipeline named SLEP (Surface Localization Extracellular Proteins), based on an automated optimal combination and sequence of usage of reliable available tools for the computational identification of the surfome, i.e. of the subset of proteins exposed on the surface of a bacterial cell.ConclusionsThe tool not only simplifies the usage of these methods, but it also improves the results by selecting the specifying order and combination of the instruments. The tool is freely available at http://www.caspur.it/slep.

Identification of a polymorphic collagen-like protein in the crustacean bacteria Pasteuria ramosa

Pasteuria ramosa is a spore-forming bacterium that infects Daphnia species. Previous results demonstrated a high specificity of host clone/parasite genotype interactions. Surface proteins of bacteria often play an important role in attachment to host cells prior to infection. We analyzed surface proteins of P. ramosa spores by two-dimensional gel electrophoresis. For the first time, we prove that two isolates selected for their differences in infectivity reveal few but clear-cut differences in protein patterns. Using internal sequencing and LC/MS/MS, we identified a collagen-like protein named Pcl1a ( Pasteuria collagen-like protein 1a). This protein, reconstructed with the help of Pasteuria genome sequences, contains three domains: a 75-amino-acid amino-terminal domain with a potential transmembrane helix domain, a central collagen-like region (CLR) containing Gly-Xaa-Yaa (GXY) repeats, and a 7-amino-acid carboxy-terminal domain. The CLR region is polymorphic among the two isolates with amino-acid substitutions and a variable number of GXY triplets. Collagen-like proteins are rare in prokaryotes, although they have been described in several pathogenic bacteria, including Bacillus cereus, Bacillus anthracis and Bacillus thuringiensis, closely related to Pasteuria species, in which they could be involved in the adherence of bacteria to host cells.

Identification of secreted and surface proteins from Enterococcus faecalis

Secreted and surface proteins of bacteria are key molecules that interface the cell with the environment. Some of them, corresponding to virulence factors, have already been described for Enterococcus faecalis, the predominant species involved in enterococcal nosocomial infections. In a global proteomic approach, the identification of the most abundant secreted and surface-associated proteins of E. faecalis JH2-2 strain was carried out. These proteins were separated by gel electrophoresis or directly subjected to in vivo trypsinolysis and then analyzed by liquid chromatography - electrospray ion trap tandem mass spectrometry. Putative functions were assigned by homology to the translated genomic database of E. faecalis. A total of 44 proteins were identified, eight secreted proteins from the supernatant culture and 38 cell surface proteins from two-dimensional gel electrophoresis and in vivo trypsinolysis among which two are common to the two groups. Their sequences analysis revealed that 35 of the 44 proteins harbour characteristic features (signal peptide or transmembrane domains) consistent with an extracellular localization. This study may be considered as an important step to encourage proteomic-based investigations of E. faecalis cell surface associated proteins that could lead to the discovery of virulence factors and to the development of new therapeutic tools.

An Important Step inListeriaLipoprotein Research

Over the last 10 years, DNA sequences of more than 600 bacterial species have been deposited in databases and are now available to search any gene, motif, or regulatory sequence of interest. Although genome data are instrumental in phylogenetic analysis and in silico design of metabolic and regulatory networks, only a very small fraction of the information has been experimentally validated. A striking example is lipoproteins predicted from genome sequences. Despite the predominance of this class of surface proteins in bacteria (up to 0.5 to 8% of the proteome), very few of these proteins have been identified as lipoproteins by biochemical methods (19). In this issue of the Journal of Bacteriology, Baumgartner et al. (2) report a systematic analysis of lipoproteins of Listeria monocytogenes, a facultative gram-positive intracellular bacterial pathogen that causes severe infections (listeriosis) in both human and animals. These authors used an L. monocytogenes mutant defective in lipoprotein diacylglyceryl transferase (Lgt), an enzyme involved in lipoprotein processing. Three aspects of their study should be highlighted: (i) new findings concerning the roles of Lgt and lipoprotein-specific signal peptidase II (Lsp) during lipoprotein processing (22); (ii) the identification of 26 of the 68 lipoproteins predicted in the initial annotation of the L. monocytogenes strain EGD-e genome (7); and (iii) experimental evidence that a few of these lipoproteins are regulated by PrfA, the master virulence regulator of L. monocytogenes (8). Below, we discuss the significance of these findings separately.

Three-Pronged Attack Advances Battle Against Infectious Bacteria

war against infectious bacteria continues. On different fronts, three groups report research with implications for therapeutic intervention and vaccine development. In Massachusetts, a drug that shows potential for treatment of sepsis has been synthesized. In California, a previously unknown mechanism of anchoring surface proteins to the cell wall of gram-positive bacteria has been elucidated—findings that may lead to a new target for therapeutic intervention. And in Montana, studies showing changes in surface proteins of bacteria that cause Lyme disease may have implications for designing vaccines. Principal scientist William J. Christ and coworkers at Eisai Research Institute (ERI) in Andover, Mass., and at Eisai's Tsukuba Research Laboratory in Ibaraki, Japan, have developed a drug, called E5531, for treatment of shock resulting from bacterial sepsis [ Science , 268 , 80 (1995)]. The condition is generally life threatening, says Michael D. Lewis, director of research at ERI. Only half of the app...