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British Journal of Cancer Aug 1972The term apoptosis is proposed for a hitherto little recognized mechanism of controlled cell deletion, which appears to play a complementary but opposite role to mitosis... (Review)
Review
The term apoptosis is proposed for a hitherto little recognized mechanism of controlled cell deletion, which appears to play a complementary but opposite role to mitosis in the regulation of animal cell populations. Its morphological features suggest that it is an active, inherently programmed phenomenon, and it has been shown that it can be initiated or inhibited by a variety of environmental stimuli, both physiological and pathological.The structural changes take place in two discrete stages. The first comprises nuclear and cytoplasmic condensation and breaking up of the cell into a number of membrane-bound, ultrastructurally well-preserved fragments. In the second stage these apoptotic bodies are shed from epithelial-lined surfaces or are taken up by other cells, where they undergo a series of changes resembling in vitro autolysis within phagosomes, and are rapidly degraded by lysosomal enzymes derived from the ingesting cells.Apoptosis seems to be involved in cell turnover in many healthy adult tissues and is responsible for focal elimination of cells during normal embryonic development. It occurs spontaneously in untreated malignant neoplasms, and participates in at least some types of therapeutically induced tumour regression. It is implicated in both physiological involution and atrophy of various tissues and organs. It can also be triggered by noxious agents, both in the embryo and adult animal.
Topics: Adrenal Glands; Animals; Atrophy; Autolysis; Carcinoma, Squamous Cell; Cell Division; Cells; Culture Techniques; Histiocytes; Homeostasis; Humans; Kinetics; Mammary Neoplasms, Experimental; Mesoderm; Microscopy, Electron; Mitosis; Phagocytosis; Rats
PubMed: 4561027
DOI: 10.1038/bjc.1972.33 -
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 -
The Journal of Experimental Medicine Oct 1914Solutions of the bodies of pneumococci, obtained by dissolving them in dilute solutions of sodium cholate, by permitting them to undergo autolysis, or by first freezing,...
Solutions of the bodies of pneumococci, obtained by dissolving them in dilute solutions of sodium cholate, by permitting them to undergo autolysis, or by first freezing, drying, and then grinding in salt solution, are actively hemolytic for rabbit, sheep, guinea pig, and human red blood corpuscles. The substance on which this hemolytic property depends is very labile, much of its activity is lost on passing through a filter, and it is destroyed by the action of trypsin. In its properties it corresponds to the substance contained in such solutions which causes the death of guinea pigs on intravenous injection. Its activity is prevented by the presence of minute amounts of cholesterin. Following the injection of this solution into rabbits and sheep, the sera of these animals acquire increased power of inhibiting its hemolytic action. It therefore possesses antigenic properties. It may therefore be concluded that the bodies of pneumococci contain a toxin that is hemolytic for red blood corpuscles. This substance is not simply a product of autolysis but undoubtedly exists preformed in the bacterial cell. However, it is not given up to the surrounding fluid as long as the bodies of the bacteria are intact. It may therefore be considered a hemolytic endotoxin.
PubMed: 19867825
DOI: 10.1084/jem.20.4.346 -
Scientific Reports Jul 2021Kluyveromyces marxianus is a yeast that could be identified from kefir and can use a broad range of substrates, such as glucose and lactate, as carbon sources. The...
Kluyveromyces marxianus is a yeast that could be identified from kefir and can use a broad range of substrates, such as glucose and lactate, as carbon sources. The lactate produced in kefir culture can be a substrate for K. marxianus. However, the complexity of the kefir microbiota makes the traits of K. marxianus difficult to study. In this research, we focused on K. marxianus cultured with lactate as the sole carbon source. The optimal growth and released protein in lactate culture were determined under different pH conditions, and the LC-MS/MS-identified proteins were associated with the tricarboxylic acid cycle, glycolysis pathway, and cellular stress responses in cells, indicating that autolysis of K. marxianus had occurred under the culture conditions. The abundant glyceraldehyde-3-phosphate dehydrogenase 1 (GAP1) was cocrystallized with other proteins in the cell-free fraction, and the low transcription level of the GAP1 gene indicated that the protein abundance under autolysis conditions was dependent on protein stability. These results suggest that lactate induces the growth and autolysis of K. marxianus, releasing proteins and peptides. These findings can be fundamental for K. marxianus probiotic and kefir studies in the future.
Topics: Culture Media; Electrophoresis, Polyacrylamide Gel; Fungal Proteins; Gene Expression Regulation, Fungal; Hydrogen-Ion Concentration; Kefir; Kluyveromyces; Lactic Acid; Multilocus Sequence Typing; Mycological Typing Techniques; Tandem Mass Spectrometry
PubMed: 34267270
DOI: 10.1038/s41598-021-94101-y -
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 -
Journal of Bacteriology Aug 2011Little is known about the molecular mechanism for autolysis of Gram-negative bacteria. In the present study, we identified the vvpS gene encoding a serine protease,...
Little is known about the molecular mechanism for autolysis of Gram-negative bacteria. In the present study, we identified the vvpS gene encoding a serine protease, VvpS, from Vibrio vulnificus, a Gram-negative food-borne pathogen. The amino acid sequence predicted that VvpS consists of two functional domains, an N-terminal protease catalytic domain (PCD) and a C-terminal carbohydrate binding domain (CBD). A null mutation of vvpS significantly enhanced viability during stationary phase, as measured by enumerating CFU and differentially staining viable cells. The vvpS mutant reduced the release of cytoplasmic β-galactosidase and high-molecular-weight extracellular chromosomal DNA into the culture supernatants, indicating that VvpS contributes to the autolysis of V. vulnificus during stationary phase. VvpS is secreted via a type II secretion system (T2SS), and it exerts its effects on autolysis through intracellular accumulation during stationary phase. Consistent with this, a disruption of the T2SS accelerated intracellular accumulation of VvpS and thereby the autolysis of V. vulnificus. VvpS also showed peptidoglycan-hydrolyzing activity, indicating that the autolysis of V. vulnificus is attributed to the self-digestion of the cell wall by VvpS. The functions of the VvpS domains were assessed by C-terminal deletion analysis and demonstrated that the PCD indeed possesses a proteolytic activity and that the CBD is required for hydrolyzing peptidoglycan effectively. Finally, the vvpS mutant exhibited reduced virulence in the infection of mice. In conclusion, VvpS is a serine protease with a modular structure and plays an essential role in the autolysis and pathogenesis of V. vulnificus.
Topics: Amino Acid Sequence; Animals; Bacterial Proteins; Bacteriolysis; Gene Expression Regulation, Bacterial; Humans; Mice; Mice, Inbred ICR; Molecular Sequence Data; Protein Structure, Tertiary; Sequence Alignment; Serine Proteases; Vibrio Infections; Vibrio vulnificus; Virulence
PubMed: 21642466
DOI: 10.1128/JB.00314-11 -
Nature Communications Jul 2023Proteins with a catalytically inactive LytM-type endopeptidase domain are important regulators of cell wall-degrading enzymes in bacteria. Here, we study their...
Proteins with a catalytically inactive LytM-type endopeptidase domain are important regulators of cell wall-degrading enzymes in bacteria. Here, we study their representative DipM, a factor promoting cell division in Caulobacter crescentus. We show that the LytM domain of DipM interacts with multiple autolysins, including the soluble lytic transglycosylases SdpA and SdpB, the amidase AmiC and the putative carboxypeptidase CrbA, and stimulates the activities of SdpA and AmiC. Its crystal structure reveals a conserved groove, which is predicted to represent the docking site for autolysins by modeling studies. Mutations in this groove indeed abolish the function of DipM in vivo and its interaction with AmiC and SdpA in vitro. Notably, DipM and its targets SdpA and SdpB stimulate each other's recruitment to midcell, establishing a self-reinforcing cycle that gradually increases autolytic activity as cytokinesis progresses. DipM thus coordinates different peptidoglycan-remodeling pathways to ensure proper cell constriction and daughter cell separation.
Topics: Humans; N-Acetylmuramoyl-L-alanine Amidase; Caulobacter crescentus; Feedback; Constriction; Autolysis
PubMed: 37433794
DOI: 10.1038/s41467-023-39783-w -
Journal of Veterinary Diagnostic... Sep 2021Estimation of the postmortem interval (PMI) is a poorly studied field in veterinary pathology. The development of field-applicable methods is needed given that animal...
Estimation of the postmortem interval (PMI) is a poorly studied field in veterinary pathology. The development of field-applicable methods is needed given that animal cruelty investigations are increasing continually. We evaluated various histologic criteria in equine brain, liver, and muscle tissue to aid the estimation of PMI in horses, which is central to forensic investigations of suspicious death. After death, autolysis proceeds predictably, depending on environmental conditions. Currently, no field-applied methods exist that accurately estimate the PMI using histology in animals or humans through quantification of autolysis. Brain, liver, and skeletal muscle from 12 freshly euthanized horses were held at 22°C and 8°C for 72 h. Tissues were sampled at T0h, T1h, T2h, T4h, T6h, T12h, T24h, T36h, T48h, T60h, and T72h. For each tissue, we quantified 5 to 7 criteria associated with autolysis, based on the percentage of microscopic field involved. Each criterion was modeled, with temperature and time as independent variables. Changes were most predictable in liver and muscle over the first 72 h postmortem. The criteria for autolysis that were present most extensively at both temperatures were hepatocyte individualization and the separation of bile duct epithelium from the basement membrane. The changes that were present next most extensively were disruption of myofiber continuity, hypereosinophilia, and loss of striation. Brain changes were highly variable. The high statistical correlation between the parameter "autolysis" and the variables "time/temperature", indicates that autolysis is progressive and predictable. Further investigation of these criteria is needed to establish histologic algorithms for PMI.
Topics: Animals; Autopsy; Feasibility Studies; Forensic Pathology; Horse Diseases; Horses; Muscle, Skeletal; Postmortem Changes
PubMed: 34109897
DOI: 10.1177/10406387211021865 -
Frontiers in Microbiology 2023
PubMed: 37234522
DOI: 10.3389/fmicb.2023.1199578 -
International Journal of Antimicrobial... Oct 2023The pathogenicity of Staphylococcus epidermidis is largely attributed to its exceptional ability to form biofilms. Here, we report that mupirocin, an antimicrobial agent...
The pathogenicity of Staphylococcus epidermidis is largely attributed to its exceptional ability to form biofilms. Here, we report that mupirocin, an antimicrobial agent widely used for staphylococcal decolonization and anti-infection, strongly stimulates the biofilm formation of S. epidermidis. Although the polysaccharide intercellular adhesin (PIA) production was unaffected, mupirocin significantly facilitated extracellular DNA (eDNA) release by accelerating autolysis, thereby positively triggering cell surface attachment and intercellular agglomeration during biofilm development. Mechanistically, mupirocin regulated the expression of genes encoding for the autolysin AtlE as well as the programmed cell death system CidA-LrgAB. Critically, through gene knockout, we found out that deletion of atlE, but not cidA or lrgA, abolished the enhancement of biofilm formation and eDNA release in response to mupirocin treatment, indicating that atlE is required for this effect. In Triton X-100 induced autolysis assay, mupirocin treated atlE mutant displayed a slower autolysis rate compared with the wild-type strain and complementary strain. Therefore, we concluded that subinhibitory concentrations of mupirocin enhance the biofilm formation of S. epidermidis in an atlE dependent manner. This induction effect could conceivably be responsible for some of the more unfavourable outcomes of infectious diseases.
Topics: Staphylococcus epidermidis; Mupirocin; Biofilms; Staphylococcus; Virulence; Bacterial Proteins
PubMed: 37385560
DOI: 10.1016/j.ijantimicag.2023.106904