Bacterial glycolipids. Glycosyl diglycerides in gram-positive bacteria.
Ontology highlight
ABSTRACT:
SUBMITTER: Brundish DE
PROVIDER: S-EPMC1265039 | biostudies-other | 1966 Jun
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Natural killer T cells (NKT cells) recognize glycolipid antigens presented by CD1d. These cells express an evolutionarily conserved, invariant T cell antigen receptor (TCR), but the forces that drive TCR conservation have remained uncertain. Here we show that NKT cells recognized diacylglycerol-containing glycolipids from Streptococcus pneumoniae, the leading cause of community-acquired pneumonia, and group B Streptococcus, which causes neonatal sepsis and meningitis. Furthermore, CD1d-dependent responses by NKT cells were required for activation and host protection. The glycolipid response was dependent on vaccenic acid, which is present in low concentrations in mammalian cells. Our results show how microbial lipids position the sugar for recognition by the invariant TCR and, most notably, extend the range of microbes recognized by this conserved TCR to several clinically important bacteria.
| S-EPMC3178673 | biostudies-literature
Project description:The composition of the Gram-positive cell wall is typically described as containing peptidoglycan, proteins and essential secondary cell wall structures called teichoic acids, which comprise approximately half of the cell wall mass. The cell walls of many species within the genera Streptococcus, Enterococcus and Lactococcus contain large amounts of the sugar rhamnose, which is incorporated in cell wall-anchored polysaccharides (CWP) that possibly function as homologues of well-studied wall teichoic acids (WTA). The presence and chemical structure of many rhamnose-containing cell wall polysaccharides (RhaCWP) has sometimes been known for decades. In contrast to WTA, insight into the biosynthesis and functional role of RhaCWP has been lacking. Recent studies in human streptococcal and enterococcal pathogens have highlighted critical roles for these complex polysaccharides in bacterial cell wall architecture and pathogenesis. In this review, we provide an overview of the RhaCWP with regards to their biosynthesis, genetics and biological function in species most relevant to human health. We also briefly discuss how increased knowledge in this field can provide interesting leads for new therapeutic compounds and improve biotechnological applications.
| S-EPMC4931226 | biostudies-literature
Project description:Signal intensities of BC-GP array for 105 speimens The Verigene Gram-Positive Blood Culture (BC-GP) nucleic acid assay is an automated microarray-based test, which can detect 12 Gram-positive bacterial genes and 3 resistance determinants using blood culture broths. We investigated signal intensities of microarray spots, and reclassified undetermined results where the automated system failed and various errors were called in blood culture specimens and spiked samples.
2014-05-30 | GSE57245 | GEO
Project description:In Gram-positive bacteria proteins are displayed on the cell surface using sortase enzymes. These cysteine transpeptidases join proteins bearing an appropriate sorting signal to strategically positioned amino groups on the cell surface. Working alone, or in concert with other enzymes, sortases either attach proteins to the cross-bridge peptide of the cell wall or they link proteins together to form pili. Because surface proteins play a fundamental role in microbial physiology and are frequently virulence factors, sortase enzymes have been intensely studied since their discovery a little more than a decade ago. Based on their primary sequences and functions sortases can be partitioned into distinct families called class A to F enzymes. Most bacteria elaborate their surfaces using more than one type of sortase that function non-redundantly by recognizing unique sorting signals within their protein substrates. Here we review what is known about the functions of these enzymes and the molecular basis of catalysis. Particular emphasis is placed on 'pilin' specific class C sortases that construct structurally complex pili. Exciting new data have revealed that these enzymes are amazingly promiscuous in the substrates that they can employ and that there is a startling degree of diversity in their mechanism of action. We also review recent data that suggest that sortases are targeted to specific sites on the cell surface where they work with other sortases and accessory factors to properly function.
| S-EPMC3590066 | biostudies-literature
Project description:Signal intensities of BC-GP array for 105 speimens The Verigene Gram-Positive Blood Culture (BC-GP) nucleic acid assay is an automated microarray-based test, which can detect 12 Gram-positive bacterial genes and 3 resistance determinants using blood culture broths. We investigated signal intensities of microarray spots, and reclassified undetermined results where the automated system failed and various errors were called in blood culture specimens and spiked samples. Signal intensity analysis of BC-GP assay. SAMPLE_077 [Blood culture, Escherichia coli, Gram-negative, BacTALERT, Supernatant, Peripheral blood] had no signal data in the array raw data. Thus, SAMPLE_077 is not represented in this Series.
2014-05-30 | E-GEOD-57245 | biostudies-arrayexpress
Project description:Protein phosphorylation in prokaryotes has gained more attention in recent years as several studies linked it to regulatory and signalling functions indicating an importance similar to protein phosphorylation in eukaryotes. Studies on bacterial phosphorylation have so far been conducted using manual or HPLC-supported phosphopeptide enrichment while automation of phosphopeptide enrichment has been established in eukaryotes, allowing for high throughput sampling. To facilitate the prospect of studying bacterial phosphorylation on a systems‐level we here establish an automated Ser/Thr/Tyr phosphopeptide enrichment workflow on the Agilent AssayMap platform. We present optimized buffer conditions for TiO2 and Fe(III)NTA-IMAC based enrichment, and the most advantageous, species specific starting amount for S. pyogenes, L. monocytogenes, and B. subtilis. Our data represents, to the best of our knowledge, the largest phosphoproteome identified by a single study for each of these bacteria. For higher sample amounts (> 250µg) we observed a superior performance of Fe(III)NTA cartridges, while more peptides were identified from smaller sample amounts using TiO2-based enrichment. Both cartridges largely enrich the same set of phosphopeptides suggesting no improvement of peptide yield from complementary use of both cartridges. Distribution of S/T/Y phosphorylation varied between bacterial strains with threonine being the main site of phosphorylation in S. pyogenes, while in B.subtilis and L. monocytogenes showed the highest percentage of phosphorylation at serine.
2021-08-26 | PXD025459 | Pride
Project description:Conjugative transfer of bacterial plasmids is the most efficient way of horizontal gene spread, and it is therefore considered one of the major reasons for the increase in the number of bacteria exhibiting multiple-antibiotic resistance. Thus, conjugation and spread of antibiotic resistance represents a severe problem in antibiotic treatment, especially of immunosuppressed patients and in intensive care units. While conjugation in gram-negative bacteria has been studied in great detail over the last decades, the transfer mechanisms of antibiotic resistance plasmids in gram-positive bacteria remained obscure. In the last few years, the entire nucleotide sequences of several large conjugative plasmids from gram-positive bacteria have been determined. Sequence analyses and data bank comparisons of their putative transfer (tra) regions have revealed significant similarities to tra regions of plasmids from gram-negative bacteria with regard to the respective DNA relaxases and their targets, the origins of transfer (oriT), and putative nucleoside triphosphatases NTP-ases with homologies to type IV secretion systems. In contrast, a single gene encoding a septal DNA translocator protein is involved in plasmid transfer between micelle-forming streptomycetes. Based on these clues, we propose the existence of two fundamentally different plasmid-mediated conjugative mechanisms in gram-positive microorganisms, namely, the mechanism taking place in unicellular gram-positive bacteria, which is functionally similar to that in gram-negative bacteria, and a second type that occurs in multicellular gram-positive bacteria, which seems to be characterized by double-stranded DNA transfer.
| S-EPMC156469 | biostudies-literature
Project description:Type IV pili (T4P) are surface-exposed fibers that mediate many functions in bacteria, including locomotion, adherence to host cells, DNA uptake (competence), and protein secretion and that can act as nanowires carrying electric current. T4P are composed of a polymerized protein, pilin, and their assembly apparatuses share protein homologs with type II secretion systems in eubacteria and the flagella of archaea. T4P are found throughout Gram-negative bacterial families and have been studied most extensively in certain model Gram-negative species. Recently, it was discovered that T4P systems are also widespread among Gram-positive species, in particular the clostridia. Since Gram-positive and Gram-negative bacteria have many differences in cell wall architecture and other features, it is remarkable how similar the T4P core proteins are between these organisms, yet there are many key and interesting differences to be found as well. In this review, we compare the two T4P systems and identify and discuss the features they have in common and where they differ to provide a very broad-based view of T4P systems across all eubacterial species.
| S-EPMC3811610 | biostudies-literature
Project description:Protein phosphorylation in prokaryotes has gained more attention in recent years as several studies linked it to regulatory and signaling functions, indicating importance similar to protein phosphorylation in eukaryotes. Studies on bacterial phosphorylation have so far been conducted using manual or HPLC-supported phosphopeptide enrichment, whereas automation of phosphopeptide enrichment has been established in eukaryotes, allowing for high-throughput sampling. To facilitate the prospect of studying bacterial phosphorylation on a systems level, we here established an automated Ser/Thr/Tyr phosphopeptide enrichment workflow on the Agilent AssayMap platform. We present optimized buffer conditions for TiO2 and Fe(III)-NTA-IMAC cartridge-based enrichment and the most advantageous, species-specific loading amounts for Streptococcus pyogenes, Listeria monocytogenes, and Bacillus subtilis. For higher sample amounts (≥250 μg), we observed superior performance of the Fe(III)-NTA cartridges, whereas for lower sample amounts (≤100 μg), TiO2-based enrichment is equally efficient. Both cartridges largely enriched the same set of phosphopeptides, suggesting no improvement of peptide yield by the complementary use of the two cartridges. Our data represent, to the best of our knowledge, the largest phosphoproteome identified in a single study for each of these bacteria.
| S-EPMC8491273 | biostudies-literature
Project description:Antimicrobial photodynamic inactivation (PDI) was shown to be a promising treatment modality for microbial infections. This study explores the effect of chitosan, a polycationic biopolymer, in increasing the PDI efficacy against Gram-positive bacteria, including Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, and methicillin-resistant S. aureus (MRSA), as well as the Gram-negative bacteria Pseudomonas aeruginosa and Acinetobacter baumannii. Chitosan at <0.1% was included in the antibacterial process either by coincubation with hematoporphyrin (Hp) and subjection to light exposure to induce the PDI effect or by addition after PDI and further incubation for 30 min. Under conditions in which Hp-PDI killed the microbe on a 2- to 4-log scale, treatment with chitosan at concentrations of as low as 0.025% for a further 30 min completely eradicated the bacteria (which were originally at ?10(8) CFU/ml). Similar results were also found with toluidine blue O (TBO)-mediated PDI in planktonic and biofilm cells. However, without PDI treatment, chitosan alone did not exert significant antimicrobial activity with 30 min of incubation, suggesting that the potentiated effect of chitosan worked after the bacterial damage induced by PDI. Further studies indicated that the potentiated PDI effect of chitosan was related to the level of PDI damage and the deacetylation level of the chitosan. These results indicate that the combination of PDI and chitosan is quite promising for eradicating microbial infections.
| S-EPMC3088195 | biostudies-literature