Clostridium botulinum in the Gulf of Thailand

Tanasugarn, L.

doi:10.1128/aem.37.2.194-197.1979

Cited by 12 publications

(5 citation statements)

References 10 publications

(7 reference statements)

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“…SFV binds to the cell plasma membrane, is internalized in coated vesicles, and fuses its membrane with that of the prelysosomal endosome compartment, releasing the nucleocapsid into the cytoplasm. Endosomes have been shown to have a pH range of 5.0-5.5 (11,29,30,34,35), and it is the acidic pH that specifically triggers the virus fusion reaction.…”

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pH-induced alterations in the fusogenic spike protein of Semliki Forest virus.

Kielian¹,

Helenius²

1985

The Journal of Cell Biology

175

155

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The spike glycoproteins of Semliki Forest virus mediate membrane fusion between the viral envelope and cholesterol-containing target membranes under conditions of mildly acidic pH (pH < 6.2). The fusion reaction is critical for the infectious cycle, catalyzing virus penetration from the acidic endosome compartment. To define the role of the viral spike glycoproteins in the fusion reaction, conformational changes in the spikes at acid pH were studied using protease digestion and binding assays to liposomes and nonionic detergent. A method was also developed to prepare fragments of both transmembrane subunit glycopolypeptides of the spike, E1 and E2, which lacked the hydrophobic anchor peptides. Unlike the intact spikes the fragments were monomeric and therefore useful for obtaining information on conformational changes in individual subunits. The results showed that both E1 and E2 undergo irreversible conformational changes at the pH of fusion, that the conformational change of E1 depends, in addition to acidic pH, on the presence of cholesterol, and that no major changes in the solubility properties of the spikes takes place. On the basis of these findings it was concluded that fusion involves both subunits of the spike and that E1 confers the stereo-specific sterol requirement. The results indicated, moreover, that acid-induced fusion of Semliki Forest virus differs in important respects from that of influenza virus, another well-defined model system for protein-mediated membrane fusion.The plasma membrane of a cell and the membrane of an enveloped animal virus form a double barrier that must be crossed by the virus genome to initiate replication. A number of animal viruses are now known to use the constitutive endocytic pathway of the cell and membrane fusion as the means of passing these membrane barriers and gaining access to the cell cytoplasm (reviewed in references 22, 24, 26, and 43). This entry pathway is best characterized for Semliki Forest virus (SFV)', an alphavirus. SFV binds to the cell plasma membrane, is internalized in coated vesicles, and fuses its membrane with that of the prelysosomal endosome compartment, releasing the nucleocapsid into the cytoplasm. Endosomes have been shown to have a pH range of 5.0-5.5 (11,29,30,34,35), and it is the acidic pH that specifically triggers the virus fusion reaction.Abbreviations used in this paper. DTBP, dimethyl-3,3'-dithiobispropionimidate; HA, hemagglutinin; MES, 2,(N-morpholino)ethane sulfonic acid; PMSF, phenylmethylsulfonyl fluoride; SFV, Semliki Forest virus; STI, soybean trypsin inhibitor; TCA, trichloroacetic acid; TX 100, Triton X-100; TX114, Triton X-114. 2284SFV fusion can also be triggered in vitro by lowering the pH and using cell plasma membranes or artificial liposomes as target membranes (36,40,41). Such in vitro studies have demonstrated that the fusion reaction is rapid (<10 s), nonleaky, has a threshold pH of 6.2, and is strictly dependent on the presence of cholesterol or other 3#-OH sterols in the target membrane (21,40). It...

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confidence: 99%

pH-induced alterations in the fusogenic spike protein of Semliki Forest virus.

Kielian¹,

Helenius²

1985

The Journal of Cell Biology

175

155

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“…In general, two potential chemical hazards of concern when using anchovy as a raw material are scombrotoxin (histamine) and botulinum toxin, where scombrotoxin is mostly associated with the consumption of certain fish prey that contain high levels of free histidine and in addition, when fish are subjected to temperature abuse during storage, bacterial decarboxylation of histidine leads to histamine formation (Magro et al, 2020;Visciano et al, 2020). Botulinum toxin is associated with the Clostridium botulinum bacterium that has long been reported to be distributed widely in marine environments such as mud, sand, seabed soil, sea water, intestinal tracts and gills of fish (Tanasugarn, 1979;Huss, 1980;Lalitha and Gopakumar, 2000).…”

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confidence: 99%

Optimal level of added salt to minimize the risk of associated chemical hazards of small-sized anchovy (Stolephorus indicus) stored at ambient and refrigerated temperatures

2022

ANRES

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Article InfoImportance of the work: Practical protocol for post-harvest handling of small-sized (less than 12 cm) anchovy by means of chilling and salting is needed to minimize the risk of associated chemical hazards. Objectives:The objective of this study was to establish the optimal level of added salt for anchovy (Stolephorus indicus) stored at different temperatures. Materials & Methods: Changes in water phase salt (WPS) and quality of anchovy (7.99 ± 0.38 cm in length) salted at 2%, 4%, 6%, 8%, 10% and 12% w/w, were monitored during 5 hr post salting at ambient temperature (33 ± 3°C) and refrigerated temperature (4 ± 1°C). Results: WPS levels of 10% or higher were achieved when the level of added salt was 8-12% w/w, while water activity values of 0.94 or lower were achieved when the level of added salt was 6-12% w/w for anchovy stored at both temperatures (p < 0.05). The time ranges practically required to reach 10% WPS during refrigerated storage of anchovy salted at 8-10% w/w and 12% w/w were 4 hr and 2 hr, respectively. After 5 hr of storage, salting anchovy at 8-12% w/w either stored at ambient or chilled temperature resulted in a histamine content below 2 mg/100 g and total volatile base nitrogen and trimethylamine contents below the limits of acceptability for human consumption. Main finding: It could be concluded that the combination of a prescribed salt level of 8-12% w/w and refrigerated storage of anchovy being used as a raw material provided a high level of assurance that the microbial growth and chemical changes could be retarded.

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“…Several species of facultatively anaerobic bacteria have been implicated as causative agents of infections resulting from exposure to polluted waters (1,2,5,8,10,12,16). There has been little mention, however, of potential health hazards presented by waterbome, obligately anaerobic bacteria for humans, although some, primarily Clostridium, have been incriminated in diseases of fish (3,17). Obligate anaerobes, especially Bacteroides and Clostridium spp., are potential human pathogens and, if present in polluted waters, may constitute an added health risk, especially to swimmers and professional divers who must work in polluted aquatic environments.…”

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confidence: 99%