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Food Research International (Ottawa,... Nov 2023Shrimp is a popular internationally traded shellfish due to its unique taste, texture, and nutritional value. Shrimp is highly perishable because it has enough free... (Review)
Review
Shrimp is a popular internationally traded shellfish due to its unique taste, texture, and nutritional value. Shrimp is highly perishable because it has enough free amino acids, high moisture levels, non-nitrogenous compounds used for microbial growth, and melanosis. Shrimp spoilage after death is caused by various reasons, like autolysis (endogenous proteinases actions during shrimp storage), growth of spoilage microorganisms, ATP degradation, melanin formation, and lipid peroxidation. A microbial byproduct, total volatile basic nitrogen, is one of the major reasons for the generation of foul odors from shrimp spoilage. Shrimp freshness monitoring is crucial for market sellers and exporters. Traditional methods for estimating shrimp freshness are expensive and inaccessible to the general public. Sensors are rapid, sensitive, selective, and portable food toxins' detection tools, devoid of expensive instruments, skilled people, sample pretreatment, and a long detection time. This review addresses shrimp spoilage causes. The mechanisms of different stages of shrimp spoilage after death, like rigor mortis, dissolution of rigor mortis, autolysis, and microbial spoilage mechanisms, are discussed. This review highlights the last five years' advances in shrimp freshness detection sensors and indicators like colorimetric pH indicators, fluorescence sensors, electronic noses, and biosensors, their working principles, and their sensitivities. Commercially available indicators and sensors for shrimp spoilage monitoring are also discussed. A review highlighting the applications of the different sensors and indicators for monitoring shrimp freshness is unavailable to date. Challenges and future perspectives in this field are explained at the end.
Topics: Humans; Rigor Mortis; Seafood; Shellfish; Time
PubMed: 37803582
DOI: 10.1016/j.foodres.2023.113270 -
Sheng Wu Gong Cheng Xue Bao = Chinese... Mar 2019Recombinant bacterial vector vaccines have been widely used as carriers for the delivery of protective antigens and nucleic acid vaccines to prevent certain infectious... (Review)
Review
Recombinant bacterial vector vaccines have been widely used as carriers for the delivery of protective antigens and nucleic acid vaccines to prevent certain infectious diseases because of their ability to induce mucosal immunity, humoral immunity and cellular immunity. However, protective antigens and nucleic acids recombined into bacterial vector vaccines are difficult to be released into host cells because of the presence of bacterial cell wall. Vaccine strains that are residual in animals or livestock products may also cause environmental contamination and spread of the vaccine strains. The effective solution for these problems is to construct an auto-lysis system that can regulate the vaccine strains to grow normally in vitro while lysis in vivo. The lysis systems that have been applied in germs mainly include: the lysis system based on regulated delayed peptidoglycan synthesis, the lysis system based on the regulation of bacteriophage lysis protein and the lysis system based on the toxin-antitoxin system. In addition, a potential lysis system based on bacterial Type Ⅵ Secretion System (T6SS) is also expected to be a new method for the construction of auto-lysis strains. This review will focus on the regulatory mechanisms of these bacterial lysis systems.
Topics: Animals; Antigens, Bacterial; Bacterial Vaccines; Vaccines, Attenuated; Vaccines, DNA
PubMed: 30912346
DOI: 10.13345/j.cjb.180283 -
Advances in Neurobiology 2019Brain glycogen is extremely difficult to study because it is very labile to physiological status and postmortem autolysis, and glycogen degradative enzymes are rapidly... (Review)
Review
Major Advances in Brain Glycogen Research: Understanding of the Roles of Glycogen Have Evolved from Emergency Fuel Reserve to Dynamic, Regulated Participant in Diverse Brain Functions.
Brain glycogen is extremely difficult to study because it is very labile to physiological status and postmortem autolysis, and glycogen degradative enzymes are rapidly activated by metabolites and signaling molecules. Glycogen is predominantly located within astrocytes in adult brain, and abnormal glycogen metabolism in neurons has lethal consequences. Diverse distribution of glycogen among subcellular compartments suggests local regulation and different functional roles, and recent studies have revealed critically important roles for glycogen in normal brain function and Lafora disease. This brief overview highlights some of the major advances in elucidation of glycogen's roles in astrocytic functions and neurotransmission and the severe consequences of aberrant neuronal glycogen metabolism.
Topics: Astrocytes; Biomedical Research; Brain; Energy Metabolism; Glycogen; Humans; Lafora Disease; Neurons
PubMed: 31667804
DOI: 10.1007/978-3-030-27480-1_1 -
ELife Jan 2022The peptidoglycan cell wall is a predominant structure of bacteria, determining cell shape and supporting survival in diverse conditions. Peptidoglycan is dynamic and...
The peptidoglycan cell wall is a predominant structure of bacteria, determining cell shape and supporting survival in diverse conditions. Peptidoglycan is dynamic and requires regulated synthesis of new material, remodeling, and turnover - or autolysis - of old material. Despite exploitation of peptidoglycan synthesis as an antibiotic target, we lack a fundamental understanding of how peptidoglycan synthesis and autolysis intersect to maintain the cell wall. Here, we uncover a critical physiological role for a widely misunderstood class of autolytic enzymes, lytic transglycosylases (LTGs). We demonstrate that LTG activity is essential to survival by contributing to periplasmic processes upstream and independent of peptidoglycan recycling. Defects accumulate in LTG mutants due to generally inadequate LTG activity, rather than absence of specific enzymes, and essential LTG activities are likely independent of protein-protein interactions, as heterologous expression of a non-native LTG rescues growth of a conditional LTG-null mutant. Lastly, we demonstrate that soluble, uncrosslinked, endopeptidase-dependent peptidoglycan chains, also detected in the wild-type, are enriched in LTG mutants, and that LTG mutants are hypersusceptible to the production of diverse periplasmic polymers. Collectively, our results suggest that LTGs prevent toxic crowding of the periplasm with synthesis-derived peptidoglycan polymers and, contrary to prevailing models, that this autolytic function can be temporally separate from peptidoglycan synthesis.
Topics: Bacterial Proteins; Cell Wall; Endopeptidases; Peptidoglycan; Periplasm; Vibrio cholerae
PubMed: 35073258
DOI: 10.7554/eLife.73178 -
Microorganisms May 2022Mutualistic bacteria have different forms of interaction with the host. In contrast to the invasion of pathogenic bacteria, naturally occurring internalization of...
Mutualistic bacteria have different forms of interaction with the host. In contrast to the invasion of pathogenic bacteria, naturally occurring internalization of commensal bacteria has not been studied in depth. Three in vitro methods, gentamicin protection, flow cytometry and confocal laser scanning microscopy, have been implemented to accurately assess the internalization of two lactobacillus strains- BL23 and GG-in Caco-2 and T84 intestinal epithelial cells (IECs) under a variety of physiological conditions and with specific inhibitors. First and most interesting, internalization occurred at a variable rate that depends on the bacterial strain and IEC line, and the most efficient was BL23 internalization by T84 and, second, efficient internalization required active IEC proliferation, as it improved naturally at the early confluence stages and by stimulation with epidermal growth factor (EGF). IFN-γ is bound to innate immune responses and autolysis; this cytokine had a significant effect on internalization, as shown by flow cytometry, but increased internalization was not perceived in all conditions, possibly because it was also stimulating autolysis and, as a consequence, the viability of bacteria after uptake could be affected. Bacterial uptake required actin polymerization, as shown by cytochalasin D inhibition, and it was partially bound to clathrin and caveolin dependent endocytosis. It also showed partial inhibition by ML7 indicating the involvement of cholesterol lipid rafts and myosin light chain kinase (MLCK) activation, at least in the LGG uptake by Caco-2. Most interestingly, bacteria remained viable inside the IEC for as long as 72 h without damaging the epithelial cells, and paracellular transcytosis was observed. These results stressed the fact that internalization of commensal and mutualistic bacteria is a natural, nonpathogenic process that may be relevant in crosstalk processes between the intestinal populations and the host, and future studies could determine its connection to processes such as commensal tolerance, resilience of microbial populations or transorganic bacterial migration.
PubMed: 35744660
DOI: 10.3390/microorganisms10061142 -
Frontiers in Microbiology 2016Vancomycin has been used as the last resort in the clinical treatment of serious infections. Vancomycin-intermediate (VISA) was discovered almost two decades ago.... (Review)
Review
Vancomycin has been used as the last resort in the clinical treatment of serious infections. Vancomycin-intermediate (VISA) was discovered almost two decades ago. Aside from the vancomycin-intermediate phenotype, VISA strains from the clinic or laboratory exhibited common characteristics, such as thickened cell walls, reduced autolysis, and attenuated virulence. However, the genetic mechanisms responsible for the reduced vancomycin susceptibility in VISA are varied. The comparative genomics of vancomycin-susceptible (VSSA)/VISA pairs showed diverse genetic mutations in VISA; only a small number of these mutations have been experimentally verified. To connect the diversified genotypes and common phenotypes in VISA, we reviewed the genetic alterations in the relative determinants, including mutations in the , and genes. Especially, we analyzed the mechanism through which diverse mutations mediate vancomycin resistance. We propose a unified model that integrates diverse gene functions and complex biochemical processes in VISA upon the action of vancomycin.
PubMed: 27790199
DOI: 10.3389/fmicb.2016.01601 -
Scientific Reports Mar 2017In contrast to many nanotoxicity studies where nanoparticles (NPs) are observed to be toxic or reduce viable cells in a population of bacteria, we observed that...
In contrast to many nanotoxicity studies where nanoparticles (NPs) are observed to be toxic or reduce viable cells in a population of bacteria, we observed that increasing concentration of TiO NPs increased the cell survival of Bacillus subtilis in autolysis-inducing buffer by 0.5 to 5 orders of magnitude over an 8 hour exposure. Molecular investigations revealed that TiO NPs prevent or delay cell autolysis, an important survival and growth-regulating process in bacterial populations. Overall, the results suggest two potential mechanisms for the disruption of autolysis by TiO NPs in a concentration dependent manner: (i) directly, through TiO NP deposition on the cell wall, delaying the collapse of the protonmotive-force and preventing the onset of autolysis; and (ii) indirectly, through adsorption of autolysins on TiO NP, limiting the activity of released autolysins and preventing further lytic activity. Enhanced darkfield microscopy coupled to hyperspectral analysis was used to map TiO deposition on B. subtilis cell walls and released enzymes, supporting both mechanisms of autolysis interference. The disruption of autolysis in B. subtilis cultures by TiO NPs suggests the mechanisms and kinetics of cell death may be influenced by nano-scale metal oxide materials, which are abundant in natural systems.
Topics: Adsorption; Bacillus subtilis; Bacteriolysis; Cell Wall; Colony Count, Microbial; Hydrogen-Ion Concentration; Kinetics; Membrane Potentials; Metal Nanoparticles; N-Acetylmuramoyl-L-alanine Amidase; Peptidoglycan; Proton-Motive Force; Titanium
PubMed: 28303908
DOI: 10.1038/srep44308 -
Scientific Reports Feb 2022Coprinus comatus, widely known as "Jituigu", is an important commodity and food in China. The yield of C. comatus, however, is substantially reduced by the autolysis of...
Coprinus comatus, widely known as "Jituigu", is an important commodity and food in China. The yield of C. comatus, however, is substantially reduced by the autolysis of the fruiting bodies after harvest. To gain insight into the molecular mechanism underlying this autolysis, we divided the growth of C. comatus fruiting bodies into four stages: infant stage (I), mature stage (M), discolored stage (D), and autolysis stage (A). We then subjected these stages to de novo transcriptomic analysis using high-throughput Illumina sequencing. A total of 12,946 unigenes were annotated and analyzed with the Gene Ontology (GO), Clusters of Orthologous Groups of proteins (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG). We analyzed the differentially expressed genes (DEGs) between stages I and M, M and D, and D and A. Because the changes from M to D are thought to be related to autolysis, we focused on the DEGs between these two stages. We found that the pathways related to metabolic activity began to vary in the transition from M to D, including pathways named as autophagy-yeast, peroxisome, and starch and sucrose metabolism. This study also speculates the possible process of the autolysis of Coprinus comatus. In addition, 20 genes of interest were analyzed by quantitative real-time PCR to verify their expression profiles at the four developmental stages. This study, which is the first to describe the transcriptome of C. comatus, provides a foundation for future studies concerning the molecular basis of the autolysis of its fruiting bodies.
Topics: China; Coprinus; Food; Fruiting Bodies, Fungal; Gene Expression Profiling; Gene Ontology; Genes, Fungal; High-Throughput Nucleotide Sequencing; Metabolic Networks and Pathways; Real-Time Polymerase Chain Reaction; Transcriptome
PubMed: 35169137
DOI: 10.1038/s41598-022-06103-z -
Current Opinion in Plant Biology Feb 2017Plant development requires specific cells to be eliminated in a predictable and genetically regulated manner referred to as programmed cell death (PCD). However, the... (Review)
Review
Plant development requires specific cells to be eliminated in a predictable and genetically regulated manner referred to as programmed cell death (PCD). However, the target cells do not merely die but they also undergo autolysis to degrade their cellular corpses. Recent progress in understanding developmental cell elimination suggests that distinct proteins execute PCD sensu stricto and autolysis. In addition, cell death alone and cell dismantlement can fulfill different functions. Hence, it appears biologically meaningful to distinguish between the modules of PCD and autolysis during plant development.
Topics: Apoptosis; Autophagy; Plant Development
PubMed: 27936412
DOI: 10.1016/j.pbi.2016.11.017 -
Journal of Veterinary Diagnostic... Mar 2024CNS tumor diagnosis in dogs often relies on immunohistochemistry (IHC) given similar histologic features among tumors. Most CNS tissue samples encountered by diagnostic...
CNS tumor diagnosis in dogs often relies on immunohistochemistry (IHC) given similar histologic features among tumors. Most CNS tissue samples encountered by diagnostic pathologists are collected during autopsy, and postmortem specimens can be susceptible to autolysis and prolonged formalin fixation, both of which have the potential to influence IHC results and interpretation. Here we evaluated the effects of experimentally controlled autolysis induced by delayed tissue fixation (sections of brain held for 2, 4, 8, 12, 24, 48, and 72 h in 0.9% NaCl at either room temperature or 37°C prior to fixation) as well as the effects of prolonged formalin fixation times (1 wk, 1 mo, 2 mo) on a panel of 8 IHC markers (CNPase, GFAP, Iba1, OLIG2, PGP9.5, MAP2, NeuN, synaptophysin) relevant to brain tumor diagnosis. Prolonged fixation of up to 2 mo had no detrimental effect on any immunomarker except NeuN, which had reduced immunolabeling intensity. Delayed fixation led to autolytic changes as expected, on a gradient of severity corresponding to increased time in saline prior to fixation. Several immunomarkers should be used with caution (CNPase, OLIG2) or avoided entirely (MAP2, NeuN) in markedly autolyzed brain and brain tumor tissues. Our results suggest that autolysis has minimal effect on most immunomarkers, but that advanced autolysis may cause a loss of specificity for GFAP, MAP2, and PGP9.5, a loss of intensity of CNPase and OLIG2, and loss of labeling with MAP2 and NeuN. Prolonged fixation affected only NeuN, with mildly decreased intensity.
Topics: Dogs; Animals; Immunohistochemistry; Formaldehyde; Brain; Tissue Fixation; Brain Neoplasms; 2',3'-Cyclic-Nucleotide Phosphodiesterases; Dog Diseases
PubMed: 38212877
DOI: 10.1177/10406387231220649