Studies on diphosphopyridine nucleotidase and platelet damaging factor in an extracellular product of Listeria monocytogenes

1970 ◽  
Vol 16 (10) ◽  
pp. 909-916 ◽  
Author(s):  
I. H. Siddique ◽  
L. C. Ying ◽  
R. A. Chung
Keyword(s):  
Listeria Monocytogenes ◽  
Hemolytic Activity ◽  
Virulent Strain ◽  
Optimal Activity ◽  
Extracellular Product ◽  
Heat Labile ◽  
Ph Range

Hemolysin preparations from a virulent strain of Listeria monocytogenes were chromatographed on Sephadex G-100 and Sephadex DEAE A-50 columns. Three types of activities were identified: DPNase activity, hemolytic activity, and platelet-damaging activity. The separation of the peak with DPN-destroying activity from the peaks with hemolytic and platelet-damaging activities provided evidence that the factor in the solutions responsible for the destruction of DPN was distinct from that causing hemolysis and platelet-damage. The DPNase factor was found to be non-dialyzable, to be heat labile, and to have optimal activity in the pH range of 6.8–7.4.

scholarly journals A STREPTOCOCCAL ENZYME THAT ACTS SPECIFICALLY UPON DIPHOSPHOPYRIDINE NUCLEOTIDE: CHARACTERIZATION OF THE ENZYME AND ITS SEPARATION FROM STREPTOLYSIN O

1957 ◽  
Vol 106 (1) ◽  
pp. 15-26 ◽  
Author(s):  
Arthur S. Carlson ◽  
Aaron Kellner ◽  
Alan W. Bernheimer ◽  
Elizabeth B. Freeman
Keyword(s):  
Electrophoretic Separation ◽  
Optimal Activity ◽  
Heat Labile ◽  
Streptolysin O ◽  
Ph Range ◽  
High Degree

All enzyme that destroys DPN has been found in fractionated and highly concentrated streptococcal preparations that also contain streptolysin O. The enzyme—streptococcal DPNase—was shown by electrophoretic separation and by other means to be distinct from streptolysin O. It is non-dialyzable, heat-labile, and has optimal activity in the pH range 7.2 to 7.8. The enzyme has a high degree of specificity for DPN, which it splits at the nicotinamide-ribose linkage.

Cleavage of immunoglobulin G by excretory–secretory cathepsin S-like protease of Spirometra mansoni plerocercoid

Parasitology ◽  
1994 ◽  
Vol 109 (5) ◽  
pp. 611-621 ◽  
Author(s):  
Y. Kong ◽  
Y.-B. Chung ◽  
S.-Y. Cho ◽  
S.-Y. Kang
Keyword(s):  
Immunoglobulin G ◽  
Cathepsin L ◽  
Immunoblot Analysis ◽  
Cathepsin S ◽  
Terminal Amino Acid ◽  
Optimal Activity ◽  
Spirometra Mansoni ◽  
Terminal Amino ◽  
Secretory Products ◽  
Ph Range

When immunoglobulin G (IgG) was incubated with Spirometra mansoni plerocercoid (sparganum), it was cleaved into Fab and Fc fragments. Fab/c fragments were also hydrolysed. The digestion was accelerated by dithiothreitol (DTT), indicating that cleavage of IgG heavy chain was due to a cysteine protease secreted into the medium. The responsible enzyme, of Mr 27 (± 0·8) kDa, was purified by a series of thiopropyl affinity, Sephacryl S-300 HR and DEAE-anion exchange chromatographies, either from worm extracts or from excretory–secretory products (ESP). The purified, thiol-dependent protease showed an optimal activity at pH 5·7 with 0·1 M sodium acetate but was active over the pH range 4·5–8·0. Its activity was inhibited completely by 10−5 M L-trans-epoxysuccinylleucylamido(4-guanidino) butane (E-64) and 1 mM iodoacetamide (IAA), but by only 53% using the specific cathepsin L inhibitor, Z-Phe-Phe-CHN2 (5 × 10−5 M). Partial NH2-terminal amino acid sequence was Leu-Pro-Asp-Ser-Val-Asn-Trp-Arg-Glu-Gly-Ala-Val-Thr-Ala-Val which showed 80% homology to human cathepsin S. Immunoblot analysis showed that sera from infected patients exhibited IgE antibody reaction. It is proposed that cleavage of immunoglobulin by an excreted–secreted, cathepsin S-like, allergenic protease is a mechanism of immune evasion used by the sparganum.

Growth, Inhibition, and Survival of Listeria monocytogenes as Affected by Acidic Conditions

1990 ◽  
Vol 53 (8) ◽  
pp. 652-655 ◽  
Author(s):  
DONALD E. CONNER ◽  
VIRGINIA N. SCOTT ◽  
DANE T. BERNARD
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Growth Inhibition ◽  
Propionic Acid ◽  
Cell Populations ◽  
Growth And Survival ◽  
Viable Cells ◽  
Acidic Conditions ◽  
Ph Range ◽  
Lactic Acids

Growth and survival of four strains of Listeria monocytogenes under acidic conditions were investigated. Tryptic soy broth with yeast extract (TSBYE) was acidified with acetic, citric, hydrochloric, lactic, or propionic acid to pH 4.0–6.0, inoculated with L. monocytogenes and incubated at 30 or 4°C. The minimum test pH at which L. monocytogenes did not grow (inhibitory pH) was determined for each acid. In the pH range tested, this inhibitory pH was 5.0 for propionic acid, 4.5 for acetic and lactic acids, and 4.0 for citric and hydrochloric acids. All four strains gave similar results. Subsequent studies were conducted at 10 and 30°C to determine changes in cell populations in TSBYE adjusted to each inhibitory pH. Initial populations of viable cells (104 CFU/ml) were reduced to <10 CFU/ml within 1–3 weeks at 30°C, whereas at 10°C, L. monocytogenes survived for 11–12 weeks in acetic, citric, or propionic acid-adjusted media and for 6 weeks in media adjusted with hydrochloric or lactic acid. The concentration of undissociated lactic acid was 0.002 M at pH 4.5.

scholarly journals Review on Pathogenic Bacteria Listeria monocytogenes, The Detection and The Sequencing Gene Methods Isolated from Meat Products

2019 ◽  
Vol 6 (2) ◽  
Author(s):  
Bhakti Etza Setiani ◽  
Yoyok Budi Pramono ◽  
Lutfi Purwitasari
Keyword(s):  
Listeria Monocytogenes ◽  
Pathogenic Bacteria ◽  
Meat Product ◽  
Meat Products ◽  
Processed Meat ◽  
Confirmation Test ◽  
Optimum Ph ◽  
Bacterium Species ◽  
Genotypic Identification ◽  
Ph Range

A study was conducted to review on pathogenic bacteria Listeria monocytogenes, the detection and the sequencing gene methods isolated from meat products, compare selected methods that detect the presence of Listeria monocytogenes in selected raw and processed meat products. Results indicate that Listeria monocytogenenes (originally named Bacterium monocytogenes) is a gram-positive, non-sporeforming, highly mobile, rod-type, and facultative anaerobic bacterium species. It can grow under temperatures between -1.5°C to 45°C and at pH range between 4.4 and 9.4, with the optimum pH of 7. Rapid methods (PCR based and VIDAS-LDUO®) detected Listeria monocytogenes faster than the conventional method. It was also gathered that Phenotypic identification and Genotypic identification are two types of confirmation test for Listeria monocytogenes. Listeria monocytogenenes can be found in raw meat and meat product because of environmental contamination, cross contamination or error process.

scholarly journals INCIDÊNCIA DE Listeria monocytogenes EM QUEIJO DE COALHO REFRIGERADO PRODUZIDO INDUSTRIALMENTE

2003 ◽  
Vol 21 (2) ◽  
Author(s):  
MARIA AURINEIDE DE ABREU CASTELO BRANCO ◽  
EVÂNIA ALTINA TEIXEIRA DE FIGUEIREDO ◽  
MARIA DE FÁTTIMA BORGES ◽  
MARIA CRISTINA DELGADO DA SILVA ◽  
MARIA TEREZA DESTRO
Keyword(s):  
Listeria Monocytogenes ◽  
Water Activity ◽  
Rapid Test ◽  
Listeria Innocua ◽  
Biochemical Tests ◽  
Listeria Species ◽  
Ph Conditions ◽  
Ph Range ◽  
Visual Reading ◽  
The City

Avaliou-se a incidência de Listeria monocytogenes em queijo de coalho, produzido industrialmente e comercializado sob refrigeração na cidade de Fortaleza- CE (Brasil). Também foram avaliadas as condições de pH e de atividade de água nas amostras contaminadas com espécies de Listeria. Foram analisadas 84 amostras de queijo de coalho industrializado de diferentes marcas empregando o TECRA Listeria Visual Immunoassay (LISVIA) modificado. Das 84 amostras, 16 (19%) estavam contaminadas com Listeria monocytogenes, 5 (5,9%) com Listeria innocua e 1 (1,2%) com Listeria grayi. Listeria monocytogenes foi isolada na faixa de pH de 5,75 a 6,37 e em atividade de água entre 0,949 e 0,970. O TECRA LISVIA detectou a presença de Listeria spp. em 9 (10,7%) amostras. Todas as amostras positivas no teste rápido foram confirmadas por testes culturais e bioquímicos e em todas foi detectada a presença de Listeria monocytogenes. O plaqueamento das amostras negativas na leitura visual do teste rápido permitiu o isolamento de Listeria spp. em 8 amostras e em 7 foi detectada a presença de Listeria monocytogenes. INCIDENCE OF Listeria monocytogenes IN INDUSTRIALLY MANUFACTURED REFRIGERATED “COALHO” CHEESE Abstract Incidence of Listeria monocytogenes in “coalho” cheese industrially manufactured and commercialized in refrigerated temperature in the city of Fortaleza, Ceará (Brazil) was evaluated. Water activity and pH conditions in the contaminated samples with Listeria species were also evaluated. Samples (84) of industrialized “coalho” cheese of different brands were analyzed using the modified TECRA Listeria Visual Immunoassay (LISVIA). From 84 samples, 16 (19%) were contaminated with Listeria monocytogenes, 5 (5.9%) with Listeria innocua and 1 (1.2%) with Listeria grayi. Listeria monocytogenes was isolated in the pH range of 5.75 to 6.37 and in water activity between 0.949 e 0.970. The TECRA LISVIA detected the presence of Listeria spp. in 9 (10.7%) samples. All positives samples in the rapid test were confirmed by cultural and biochemical tests and in all samples the presence of Listeria monocytogenes was detected. The negative samples plating in the visual reading of the rapid test allowed the isolation of Listeria spp. in 8 samples and in 7 the presence of Listeria monocytogenes was detected.

scholarly journals Conversion of Shrimp Head Waste for Production of a Thermotolerant, Detergent-Stable, Alkaline Protease by Paenibacillus sp.

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 798 ◽  
Author(s):  
Chien Thang Doan ◽  
Thi Ngoc Tran ◽  
I-Hong Wen ◽  
Van Bon Nguyen ◽  
Anh Dzung Nguyen ◽  
...  
Keyword(s):  
Alkaline Protease ◽  
Nitrogen Nutrition ◽  
Crab Shell ◽  
Carbon And Nitrogen ◽  
Optimal Activity ◽  
Shrimp Shell ◽  
Paenibacillus Sp ◽  
Shrimp Head ◽  
Ph Range ◽  
By Products

Fishery processing by-products have been of great interest to researchers due to their beneficial applications in many fields. In this study, five types of marine by-products, including demineralized crab shell, demineralized shrimp shell, shrimp head, shrimp shell, and squid pen, provided sources of carbon and nitrogen nutrition by producing a protease from Paenibacillus sp. TKU047. Strain TKU047 demonstrated the highest protease productivity (2.98 U/mL) when cultured for two days on a medium containing 0.5% of shrimp head powder (SHP). The mass of TKU047 protease was determined to be 32 kDa (approximately). TKU047 protease displayed optimal activity at 70–80 °C and pH 9, with a pH range of stability from 6 to 11. TKU047 protease also showed stability in solutions containing surfactants and detergents. Based on its excellent properties, Paenibacillus sp. TKU047 protease may be a feasible candidate for inclusion in laundry detergents.

Contribution of cysteine residue to the properties of Listeria monocytogenes listeriolysin O

2009 ◽  
Vol 55 (10) ◽  
pp. 1153-1159 ◽  
Author(s):  
Radosław Stachowiak ◽  
Jarosław Wiśniewski ◽  
Olga Osińska ◽  
Jacek Bielecki
Keyword(s):  
Listeria Monocytogenes ◽  
Hemolytic Activity ◽  
Cysteine Residue ◽  
Listeriolysin O ◽  
Wild Type ◽  
Gram Positive Bacteria ◽  
Culture Model ◽  
The Family ◽  
Kinetics Of

Listeriolysin (LLO) is the key virulence factor critical for Listeria monocytogenes pathogenesis. Listerial cytolysin belongs to the family of cholesterol-dependent cytolysins (CDCs), a group of pore-forming toxins produced by related gram-positive bacteria. Most CDCs contain a cysteine residue in the conserved undecapeptide — a sequence that is highly preserved among this group of proteins. Substitutions of cysteine do not always lead to loss of hemolytic activity, questioning the purpose of such strong conservation of this amino acid in the sequence of CDC. The properties of 3 L. monocytogenes strains, a wild type and 2 mutants expressing modified LLO within the cysteine residue, were analyzed in this work. The first of these mutants producing a toxin with cysteine to alanine substitution showed similar features to the wild type except that a thiol-reducing agent was not necessary for hemolytic activity. Another strain secreting LLO containing serine instead of cysteine exhibited strikingly different properties than the wild type. Modified toxin is independent of the reducing reagents, less stable, and shows accelerated kinetics of cytolysis in comparison with the unchanged protein. However, both mutant strains are less invasive in the cell culture model showing the important role of cysteine in L. monocytogenes virulence.

scholarly journals Real-Time Measurements of the Interaction between Single Cells of Listeria monocytogenes and Nisin on a Solid Surface

2000 ◽  
Vol 66 (8) ◽  
pp. 3586-3591 ◽  
Author(s):  
Birgitte Bjørn Budde ◽  
Mogens Jakobsen
Keyword(s):  
Listeria Monocytogenes ◽  
Real Time ◽  
Solid Surface ◽  
Immobilized Cells ◽  
Single Cells ◽  
Lag Phase ◽  
Nisin Concentration ◽  
Fluorescence Ratio Imaging ◽  
Ratio Imaging ◽  
Ph Range

ABSTRACT A method to obtain real-time measurements of the interactions between nisin and single cells of Listeria monocytogenes on a solid surface was developed. This method was based on fluorescence ratio-imaging microscopy and measurements of changes in the intracellular pH (pHi) of carboxyfluorescein succinimidyl ester-stained cells during exposure to nisin. Immobilized cells were placed in a chamber mounted on a microscope and attached to a high-precision peristaltic pump which allowed rapid changes in the nisin concentration. In the absence of nisin, the pHi ofL. monocytogenes was almost constant (approximately pH 8.0) and independent of the external pH in the pH range from 5.0 to 9.0. In the presence of nisin, dissipation of the pH gradient (ΔpH) was observed, and this dissipation was both time and nisin concentration dependent. The dissipation of ΔpH resulted in cell death, as determined by the number of CFU. In the model system which we used the immobilized cells were significantly more resistant to nisin than the planktonic cells. The kinetics of ΔpH dissipation for single cells revealed a variable lag phase depending on the nisin concentration, which was followed by a very rapid decrease in pHi within 1 to 2 min. The differences in nisin sensitivity between single cells in a L. monocytogenes population were insignificant for cells grown to the stationary phase in a liquid laboratory substrate, but differences were observed for cells grown on an agar medium under similar conditions, which resulted in some cells having increased resistance to nisin.

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