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Nature Chemical Biology Aug 2021Extracellular peptidoglycan-linked polysaccharide modifications mediate cell morphology, division, and autolysis in some Gram-positive bacterial pathogens. A new study...
Extracellular peptidoglycan-linked polysaccharide modifications mediate cell morphology, division, and autolysis in some Gram-positive bacterial pathogens. A new study shows that the degree and location of a specific modification controls peptidoglycan hydrolysis and placement of the axis of cell division.
Topics: Cell Division; Cues; Spindle Apparatus
PubMed: 34045746
DOI: 10.1038/s41589-021-00818-2 -
World Journal of Microbiology &... Aug 2018Brewer's yeast is used in production of beer since millennia, and it is receiving increased attention because of its distinct fermentation ability and other biological... (Review)
Review
Brewer's yeast is used in production of beer since millennia, and it is receiving increased attention because of its distinct fermentation ability and other biological properties. During fermentation, autolysis occurs naturally at the end of growth cycle of yeast. Yeast cell wall provides yeast with osmotic integrity and holds the cell shape upon the cell wall stresses. The cell wall of yeast consists of β-glucans, chitin, mannoproteins, and proteins that cross linked with glycans and a glycolipid anchor. The variation in composition and amount of cell wall polysaccharides during autolysis in response to cell wall stress, laying significant impacts on the autolysis ability of yeast, either benefiting or destroying the flavor of final products. On the other hand, polysaccharides from yeast cell wall show outstanding health effects and are recommended to be used in functional foods. This article reviews the influence of cell wall polysaccharides on yeast autolysis, covering cell wall structure changings during autolysis, and functions and possible applications of cell wall components derived from yeast autolysis.
Topics: Cell Wall; Chitin; Fermentation; Glycolipids; Membrane Glycoproteins; Polysaccharides; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Stress, Physiological
PubMed: 30128783
DOI: 10.1007/s11274-018-2508-6 -
Molecules (Basel, Switzerland) Oct 2018Trypsin is the protease of choice for protein sample digestion in proteomics. The most typical active forms are the single-chain β-trypsin and the two-chain α-trypsin,... (Review)
Review
Trypsin is the protease of choice for protein sample digestion in proteomics. The most typical active forms are the single-chain β-trypsin and the two-chain α-trypsin, which is produced by a limited autolysis of β-trypsin. An additional intra-chain split leads to pseudotrypsin (ψ-trypsin) with three chains interconnected by disulfide bonds, which can be isolated from the autolyzate by ion-exchange chromatography. Based on experimental data with artificial substrates, peptides, and protein standards, ψ-trypsin shows altered kinetic properties, thermodynamic stability and cleavage site preference (and partly also cleavage specificity) compared to the above-mentioned proteoforms. In our laboratory, we have analyzed the performance of bovine ψ-trypsin in the digestion of protein samples with a different complexity. It cleaves predominantly at the characteristic trypsin cleavage sites. However, in a comparison with common tryptic digestion, non-specific cleavages occur more frequently (mostly after the aromatic residues of Tyr and Phe) and more missed cleavages are generated. Because of the preferential cleavages after the basic residues and more developed side specificity, which is not expected to occur for the major trypsin forms (but may appear anyway because of their autolysis), ψ-trypsin produces valuable information, which is complementary in part to data based on a strictly specific trypsin digestion and thus can be unnoticed following common proteomics protocols.
Topics: Animals; Autolysis; Cattle; Enzyme Stability; Kinetics; Protein Isoforms; Proteolysis; Trypsin
PubMed: 30322187
DOI: 10.3390/molecules23102637 -
Journal of Experimental Botany Mar 2021In this review, I discuss the possibility that dying cells produce much of the auxin in vascular plants. The natural auxin, indole-3-acetic acid (IAA), is derived from... (Review)
Review
In this review, I discuss the possibility that dying cells produce much of the auxin in vascular plants. The natural auxin, indole-3-acetic acid (IAA), is derived from tryptophan by a two-step pathway via indole pyruvic acid. The first enzymes in the pathway, tryptophan aminotransferases, have a low affinity for tryptophan and break it down only when tryptophan levels rise far above normal intracellular concentrations. Such increases occur when tryptophan is released from proteins by hydrolytic enzymes as cells autolyse and die. Many sites of auxin production are in and around dying cells: in differentiating tracheary elements; in root cap cells; in nutritive tissues that break down in developing flowers and seeds; in senescent leaves; and in wounds. Living cells also produce auxin, such as those transformed genetically by the crown gall pathogen. IAA may first have served as an exogenous indicator of the presence of nutrient-rich decomposing organic matter, stimulating the production of rhizoids in bryophytes. As cell death was internalized in bryophytes and in vascular plants, IAA may have taken on a new role as an endogenous hormone.
Topics: Apoptosis; Indoleacetic Acids; Plant Cells; Plant Leaves; Plants; Tryptophan; Tryptophan Transaminase
PubMed: 33460445
DOI: 10.1093/jxb/erab009 -
Comprehensive Reviews in Food Science... Nov 2022Autolysis technology has shown potential for protein hydrolysates production from marine and aquaculture byproducts. Viscera are a source of cheap proteolytic enzymes... (Review)
Review
Autolysis technology has shown potential for protein hydrolysates production from marine and aquaculture byproducts. Viscera are a source of cheap proteolytic enzymes for producing protein hydrolysates from the whole fish or processing byproducts of the most valuable commercial species by applying autolysis technology. The use of autolysis allows economical production of protein hydrolysate and provides an opportunity to valorize downstream fish and shellfish processing byproducts at a lower cost. As a result, production and application of marine byproduct autolysates is increasing in the global protein hydrolysates market. Nevertheless, several restrictions occur with autolysis, including lipid and protein oxidation mediated by the heterogeneous composition of byproducts. The generally poor storage and handling of byproducts may increase the formation of undesirable metabolites during autolysis, which can be harmful. The formation of nitrogenous compounds (i.e., biogenic amines), loss of freshness, and process of autolysis in the byproducts could increase the rate of quality and safety loss and lead to more significant concern about the use of autolysates for human food applications. The current review focuses on the autolysis process, which is applied for the hydrolysis of aquaculture and marine discards to obtain peptides as functional or nutritive ingredients. It further addresses the latest findings on the mechanisms and factors contributing the deterioration of byproducts and possible ways to control oxidation and other food quality and safety issues in raw materials and protein hydrolysates.
Topics: Animals; Humans; Protein Hydrolysates; Hydrolysis; Aquaculture; Fishes; Peptides
PubMed: 36321667
DOI: 10.1111/1541-4337.13060 -
The American Journal of Forensic... Dec 2014Examination of the decomposed brain is a largely neglected area of forensic neuropathology. However, careful examination often yields valuable information that may... (Review)
Review
Examination of the decomposed brain is a largely neglected area of forensic neuropathology. However, careful examination often yields valuable information that may assist in criminal proceedings. Decomposition encompasses the processes of autolysis, putrefaction, and decay. Most decomposed brains will be affected by both autolysis and putrefaction, resulting in a brain that may, at one end of the spectrum, be almost normal or, at the other end, pulpified, depending on the conditions in which the body remained after death and the postmortem interval. Naked eye examination may detect areas of hemorrhage and also guides appropriate sampling for histology. Histological appearances are often better than what would be predicted from the state of the brain. Histology often confirms macroscopic abnormalities and may also reveal other features such as ischemic injury. Silver staining demonstrates neuritic plaques, and immunocytochemistry for β-amyloid precursor protein and other molecules produces results comparable with those seen in well-preserved fixed brains. The usefulness of information derived from the examination of the decomposed brain in criminal proceedings is illustrated with 6 case reports drawn from the author's own practice.
Topics: Adult; Aged; Autopsy; Brain; Child, Preschool; Female; Forensic Pathology; Homicide; Humans; Male; Middle Aged; Postmortem Changes; Young Adult
PubMed: 25384305
DOI: 10.1097/PAF.0000000000000111 -
Environmental Microbiology May 2021It is known that Bacillus subtilis releases membrane vesicles (MVs) during the SOS response, which is associated with cell lysis triggered by the PBSX prophage-encoded...
It is known that Bacillus subtilis releases membrane vesicles (MVs) during the SOS response, which is associated with cell lysis triggered by the PBSX prophage-encoded cell-lytic enzymes XhlAB and XlyA. In this study, we demonstrate that MVs are released under various stress conditions: sucrose fatty acid ester (SFE; surfactant) treatment, cold shock, starvation, and oxygen deficiency. B. subtilis possesses four major host-encoded cell wall-lytic enzymes (autolysins; LytC, LytD, LytE, and LytF). Deletions of the autolysin genes abolished autolysis and the consequent MV production under these stress conditions. In contrast, deletions of xhlAB and xlyA had no effect on autolysis-triggered MV biogenesis, indicating that autolysis is a novel and prophage-independent pathway for MV production in B. subtilis. Moreover, we found that the cell lysis induced by the surfactant treatment was effectively neutralized by the addition of exogenous purified MVs. This result suggests that the MVs can serve as a decoy for the cellular membrane to protect the living cells in the culture from membrane damage by the surfactant. Our results indicate a positive effect of B. subtilis MVs on cell viability and provide new insight into the biological importance of the autolysis phenomenon in B. subtilis.
Topics: Autolysis; Bacillus subtilis; Cell Membrane; Humans; N-Acetylmuramoyl-L-alanine Amidase
PubMed: 33817925
DOI: 10.1111/1462-2920.15502 -
Current Genetics Feb 2016In textbooks, DNA is generally defined as the universal storage material for genetic information in all branches of life. Beyond this important intracellular role, DNA... (Review)
Review
In textbooks, DNA is generally defined as the universal storage material for genetic information in all branches of life. Beyond this important intracellular role, DNA can also be present outside of living cells and is an abundant biopolymer in aquatic and terrestrial ecosystems. The origin of extracellular DNA in such ecological niches is diverse: it can be actively secreted or released by prokaryotic and eukaryotic cells by means of autolysis, apoptosis, necrosis, bacterial secretion systems or found in association with extracellular bacterial membrane vesicles. Especially for bacteria, extracellular DNA represents a significant and convenient element that can be enzymatically modulated and utilized for multiple purposes. Herein, we discuss briefly the main origins of extracellular DNA and the most relevant roles for the bacterial physiology, such as biofilm formation, nutrient source, antimicrobial means and horizontal gene transfer.
Topics: Bacterial Physiological Phenomena; Biofilms; DNA, Bacterial; Energy Metabolism; Extracellular Matrix; Extracellular Space; Gene Transfer, Horizontal; Quorum Sensing
PubMed: 26328805
DOI: 10.1007/s00294-015-0514-x -
Frontiers in Cellular and Infection... 2023is a model quorum sensing (QS) pathogen with three interconnected QS circuits that control the production of virulence factors and antibiotic tolerant biofilms. The QS...
is a model quorum sensing (QS) pathogen with three interconnected QS circuits that control the production of virulence factors and antibiotic tolerant biofilms. The QS system of is responsible for the biosynthesis of diverse 2-alkyl-4-quinolones (AQs), of which 2-heptyl-4-hydroxyquinoline (HHQ) and 2-heptyl-3-hydroxy-4()-quinolone (PQS) function as QS signal molecules. Transcriptomic analyses revealed that HHQ and PQS influenced the expression of multiple genes via PqsR-dependent and -independent pathways whereas 2-heptyl-4-hydroxyquinoline -oxide (HQNO) had no effect on transcriptome. HQNO is a cytochrome inhibitor that causes programmed cell death and autolysis. However, mutants unable to synthesize HQNO undergo autolysis when grown as colony biofilms. The mechanism by which such autolysis occurs is not understood. Through the generation and phenotypic characterization of multiple PAO1 mutants producing altered levels of AQs in different combinations, we demonstrate that mutation of results in the accumulation of HHQ which in turn leads to Pf4 prophage activation and consequently autolysis. Notably, the effect of HHQ on Pf4 activation is not mediated its cognate receptor PqsR. These data indicate that the synthesis of HQNO in PAO1 limits HHQ-induced autolysis mediated by Pf4 in colony biofilms. A similar phenomenon is shown to occur in cystic fibrosis (CF) isolates, in which the autolytic phenotype can be abrogated by ectopic expression of .
Topics: Humans; Quinolones; Quorum Sensing; Pseudomonas aeruginosa; Prophages; Biofilms; Autolysis
PubMed: 37305419
DOI: 10.3389/fcimb.2023.1183681