G. K. Chesterton and the Dickens Fellowship

Makinen, Merja

doi:10.5840/chesterton198511460

Cited by 6 publications

(15 citation statements)

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“…This protein has been shown to enhance enterococcal adherence to renal cells (Joyanes et al, 2000) and to mediate internalization of E. faecalis by cultured human intestinal epithelial cells (Olmsted et al, 1994). In contrast, gelatinase is a protease that hydrolyses gelatin, collagen, casein, haemoglobin and other bioactive peptides (Coque et al, 1995), which suggests a role in inflammatory processes (Makinen et al, 1989). Other variable traits associated with enterococcal virulence are the enterococcal surface protein (Esp), which may contribute to the ability of E. faecalis to evade detection by the immune system (Shankar et al, 1999) and the EfaA proteins which are homologues of cell surface adhesions found on a number of streptococcal species (Lowe et al, 1995;Singh et al, 1998) and are expressed in serum.…”

Section: Introductionmentioning

confidence: 99%

“…This protein has been shown to enhance enterococcal adherence to renal cells (Joyanes et al, 2000) and to mediate internalization of E. faecalis by cultured human intestinal epithelial cells (Olmsted et al, 1994). In contrast, gelatinase is a protease that hydrolyses gelatin, collagen, casein, haemoglobin and other bioactive peptides (Coque et al, 1995), which suggests a role in inflammatory processes (Makinen et al, 1989 the EfaA proteins which are homologues of cell surface adhesions found on a number of streptococcal species (Lowe et al, 1995;Singh et al, 1998) and are expressed in serum. In addition, sex pheromones are peptides expressed prior to conjugation which induce genes on the plasmid of the donor strain to produce aggregation substance, thus increasing the frequency of plasmid transfer (Clewell 1990;Simjee & Gill, 1997).…”

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confidence: 99%

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Production of enterolysin A by a raw milk enterococcal isolate exhibiting multiple virulence factors

et al. 2003

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Even though enterococci are a common cause of human infection they can readily be isolated from a range of food sources, including various meat and dairy products. An enterococcal strain, DPC5280, which exhibits a broad spectrum of inhibition against many Gram-positive bacteria was recently isolated from an Irish raw milk sample. Characterization of the inhibition revealed that the strain exhibits haemolytic activity characteristic of the two-component lantibiotic cytolysin and also produces a heat-labile antimicrobial protein of 34 kDa. The latter protein displayed cell wall hydrolytic activity, as evidenced by zymogram gels containing autoclaved lactococcal cells. N-terminal sequencing of the purified protein yielded the sequence ASNEWS which is 100 % identical to enterolysin A (accession no. AF249740), a protein which shares 28 and 29 % identity to the Gly-Gly endopeptidases, lysostaphin and zoocin A, respectively. Indeed, amplification of entL from DPC5280 and sequencing revealed that the protein is 100 % identical to enterolysin A. The DPC5280 strain also contained the determinants associated with multiple virulence factors, including gelatinase, aggregation substance and multiple antibiotic resistance. The linkage of this cell-wall-degrading enzyme to other virulence factors in enterococci may contribute to the competitiveness of pathogenic enterococci when found in complex microbial environments such as food and the gastrointestinal tract. INTRODUCTIONDespite the fact that foods containing enterococci have a long history of safe use, these organisms are not considered as GRAS (generally recognized as safe) organisms. They can readily be isolated from a range of food sources, including raw milk, and are often a constituent of some mixed starter strains used commercially. However, many strains can act as opportunistic pathogens, causing a variety of infections such as urinary tract infections, bacteremia and infective endocarditis (Murray, 1990;Jett et al., 1994), and are of major importance in community-acquired and in hospital-acquired (nosocomial) infections (Jett et al., 1994;Low et al., 1994;Jones et al., 1997;Simjee & Gill, 1997). A contributing factor to their pathogenesis is their evolving resistance to antibiotics. For example, resistance to the antibiotic vancomycin is now widespread among members of the genus, which leaves few options for disease management (Aguirre & Collins, 1993;Knudtson & Hartman, 1993;Facklam & Sahm, 1995;Klein et al., 1998). Considerable progress has recently been made in determining the traits responsible for pathogenesis of enterococci.For example, studies have shown that phenotypes such as production of cytolysin, which has both haemolytic activity (by lysing a broad spectrum of cells, including human, horse and rabbit erythrocytes) and bactericidal activity (against Gram-positive bacteria) play a role in the progression of enterococcal infection (Ike et al., 1984;Jett et al., 1992). Cytolysin enhances the virulence of Enterococcus faecalis in animal models, such as muri...

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Section: Introductionmentioning

confidence: 99%

“…This protein has been shown to enhance enterococcal adherence to renal cells (Joyanes et al, 2000) and to mediate internalization of E. faecalis by cultured human intestinal epithelial cells (Olmsted et al, 1994). In contrast, gelatinase is a protease that hydrolyses gelatin, collagen, casein, haemoglobin and other bioactive peptides (Coque et al, 1995), which suggests a role in inflammatory processes (Makinen et al, 1989 the EfaA proteins which are homologues of cell surface adhesions found on a number of streptococcal species (Lowe et al, 1995;Singh et al, 1998) and are expressed in serum. In addition, sex pheromones are peptides expressed prior to conjugation which induce genes on the plasmid of the donor strain to produce aggregation substance, thus increasing the frequency of plasmid transfer (Clewell 1990;Simjee & Gill, 1997).…”

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confidence: 99%

Production of enterolysin A by a raw milk enterococcal isolate exhibiting multiple virulence factors

et al. 2003

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“…The preparation obtained from the final step was used in this study. Estimation of aminopeptidase B actikity by azo-eoupling in the presence of 0.2 M NaCl has also been described earlier (5,6) as well as most of the methods empIoyed to characterize the two molecular forms discovered.…”

Section: Methodsmentioning

confidence: 83%

Evidence on Erythrocyte Aminopeptidase B

Mäkinen

1971

International Journal of Protein Research

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Purified rat liver aminopeptidase B preparations were found to contain two molecular forms of the enzyme which can be separated by preparative electrophoresis on poly‐acrylamide columns. The one with higher electrophoretic mobility represents the actual liver enzyme and the one with lower electrophoretic mobility was seen to be derived most likely from hemolyzed red blood cells constantly present in liver homo‐genates. This was proved by purifying aminopeptidase B directly from isolated rat erythrocytes with the same procedure earlier used for the liver enzyme. The enzymic properties of the three enzymes (two derived from livers and one derived from erythrocytes) were seen to be largely the same. The similarity was especially considerable in the kinetics of the enzyme‐catalyzed reactions, where substrate inhibition was seen to be the most characteristic feature.

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“…All reagents and commercial enzyme preparations and the preparations of aminopeptidase B were the same as described earlier (6). In addition, bacitracin (activity about 55 units per mg) was purchased from Mann Research Laboratories, Inc. (New York, N.Y., U S A . )…”

Section: Chemicals and Enzymesmentioning

confidence: 99%

“…All enzyme assays were carried out as earlier (6). The kinetics and the performance of the calculations from experimental data by the aid of a computer program have been published earlier (1 1).…”

Section: Kineticsmentioning

confidence: 99%

Inhibition by Bacitracin of Some Hydrolytic Enzymes

Mäkinen

1972

International Journal of Peptide and Protein Research

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Bacitracin was seen to inhibit noncompetitively the papain‐catalyzed hydrolysis of N‐benzoyl‐DL‐arginyl‐2‐naphthylamine and the hydrolysis of N‐L‐leucyl‐2‐naphthyl‐amine catalyzed by subtilisin, papain, and leucine aminopeptidase. Alkaline phosphatase of E. coli, aminopeptidase B of rat liver, and trypsin were not affected to any noticeable extent. α‐Chymotrypsin was only slightly inhibited. The bacitracin preparation studied was not found to contain zinc (when determined with an atomic absorption spectrophotometer). The values of K i for the inhibition of papain, subtilisin, and leucine aminopeptidase were determined to be 5.0, 4.5, and 2.0 mM, respectively. The values of the maximum velocity, V, and the substrate constant, K s, at different concentrations of bacitracin were calculated for trypsin, papain, subtilisin, and leucine amino‐peptidase by the aid of a computer program using the Hanes' equation. Bacitracin also inhibited some aminopeptidase‐like enzymes of human fetal liver, human oral fluid, and gingiva. The enzymes hydrolyzing N‐L‐leucyl‐2‐naphthylamine were the strongest inhibited and those hydrolyzing N‐L‐prolyl‐2‐naphthylamine the least inhibited. The selective effect of bacitracin was explained in terms of substrate specificity of the enzymes and in terms of different topology of enzyme surface around the active site. The enzymes which were inhibited more strongly (papain, subtilisin, and leucine aminopeptidase) were considered to be inhibited due to the “open” structure of their active centers.

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G. K. Chesterton and the Dickens Fellowship

Cited by 6 publications

References 0 publications

Production of enterolysin A by a raw milk enterococcal isolate exhibiting multiple virulence factors

Production of enterolysin A by a raw milk enterococcal isolate exhibiting multiple virulence factors

Evidence on Erythrocyte Aminopeptidase B

Inhibition by Bacitracin of Some Hydrolytic Enzymes

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