Toxic Lysolipoid: Isolation from
            <i>Pseudomonas pseudomallei</i>

Redfearn, M.

doi:10.1126/science.146.3644.648

Cited by 6 publications

(2 citation statements)

References 15 publications

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“…The fl-haemolysin of A. caviae resembles that of Porphyromonas gingivalis [25] as they are stimulated by both Mg2" and Ca2+ ions and inhibited by EDTA whereas an exotoxin of Proteus vulgaris, P. mirabilis and P. morganii [26] and lysolipoid endotoxin of Pseudomonas pseudomallei [27] required only Ca2+ for their enhanced activity. Although the reducing agents, dithiothreitol and mercaptoethanol enhanced the haemolytic toxin activity of A. caviae, cysteine and glutathione inhibited the activity to a certain extent.…”

Section: Discussionmentioning

confidence: 99%

Characterisation of haemolytic activity fromAeromonas caviae

Karunakaran

Devi

1994

Epidemiol. Infect.

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SUMMARYAeromonas caviae, an enteropathogen associated with gastroenteritis, displays several virulence characteristics. Studies on the kinetics of growth of A. caviae and expression of fl-haemolytic toxin revealed that A. caviae produced maximum haemolytic activity extracellularly during the stationary phase. Preliminary studies on the properties of A. caviae haemolysin suggested that divalent cations (Mg2+ and Ca2+ ) and thiol compounds, dithiothreitol and mercaptoethanol enhanced the haemolytic activity. Addition of L-cysteine, glutathione and EDTA reduced the haemolytic activity. The iron chelator, 2-2' bipyridyl, significantly inhibited the growth of A. caviae possibly by iron limitation, with parallel enhancement of haemolysin production compared to A. caviae grown in excess of iron. These results suggest that A. caviae produces only ,1-haemolysin, which resembles the haemolysins reported for several other bacteria and the activity might be regulated by environmental factors especially iron. INTRODUCTIONThere is increasing evidence that the enteropathogen Aeromonas caviae is a causative agent of gastroenteritis [1][2][3][4][5][6] and is a predominant isolate among the microbiota of diarrhoeal stool specimens of infants, from intestinal and extraintestinal infections, and from aquatic ecosystems [4,[7][8][9][10]. The regulation and expression of putative microbial virulence factors by the environment and cytoadherence to host cells are essential events in the establishment of pathogenicity. A. caviae has various such potential pathogenic attributes. It produces either or both thermostable metalloprotease and a thermolabile serine protease [11, 12]. A. caviae has been shown to adhere to host cells [4,13,14] and cause structural damage; and even cell death in some cases by displaying cytotoxic factors [4,6,15]. A. caviae produces an extracellular heat-stable cytotoxin that is lethal to HEp-2 cells [4,16] and a cytotoxic enterotoxin that exhibits cross-reaction with the cholera toxin [4,6,13,15]. It also encodes either

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Section: Discussionmentioning

confidence: 99%

Characterisation of haemolytic activity fromAeromonas caviae

Karunakaran

Devi

1994

Epidemiol. Infect.

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“…Pseudomonas aeruginosa produced at least two hemolysins, one heat labile and identical to phospholipase C and the other a heat-stable glycolipid (1). The Pseudomonas cepacia hemolysin (39) was similar to the Pseudomonas pseudomallei hemolysin, which produces a hemolytic lysolipoid endotoxin (42). Almost 70% of the hemolytic activity of P. pseudomallei strains occurred in the growth supernatant, and, interestingly, Ca2+, EDTA, N-ethylmaleimide, and p-chloromercuribenzoate enhanced or were inhibitory to its activity.…”

Section: Discussionmentioning

confidence: 99%

Hemolytic activity in the periodontopathogen Porphyromonas gingivalis: kinetics of enzyme release and localization

et al. 1991

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Porphyromonas gingivalis W50, W83, A7A1-28, and ATCC 33277 were investigated for their abilities to lyse sheep, human, and rabbit erythrocytes. All of the P. gingivalis strains studied produced an active hemolytic activity during growth, with maximum activity occurring in late-exponential-early-stationary growth phase. The enzyme was cell bound and associated with the outer membrane. Fractionation of P. gingivalis W50 localized the putative hemolysin almost exclusively in the outer membrane fraction, with significant hemolytic activity concentrated in the outer membrane vesicles. Ca2' and Mg2+ ions significantly increased the expression of hemolytic activity. Hemolytic activity was inhibited by proteinase K, trypsin, the proteinase inhibitors NaP -tosyl-L-lysine chloromethyl ketone and benzamidine, the metabolic inhibitor M-chlorophenylhydrazone, and iodoacetate. KCN and sodium azide (NaN3) only partially inhibited P. gingivalis hemolytic activity, while antiserum to whole cells of each of the P. gingivalis strains had a significant inhibitory effect on hemolytic activity. The P. gingivalis W50 hemolysin was inhibited by cysteine, dithiothreitol, and glutathione at concentrations of at least 10 mM; at low concentrations (i.e., 2 mM), dithiothreitol did not completely inhibit hemolytic activity. Heating to temperatures above 55°C resulted in an almost complete inhibition of hemolytic activity. The effect of heme limitation (i.e., iron) on hemolysin production indicated that either limitation or starvation for heme resulted in significantly increased hemolysin production compared with that of P. gingivalis grown in the presence of excess heme. * Corresponding author. and Gharbia (45) clearly demonstrate that heme modulates P. gingivalis virulence. Kay et al. (23) have demonstrated that their P. gingivalis W50 strain also possessed hemolytic activity, which appeared to be concentrated in the extracellular vesicles. The report presented here describes a putative hemolysin which is sensitive to-SH-containing molecules and appears to have a close association with the outer membrane and outer membrane vesicles. MATERIALS AND METHODS Culture conditions. P. gingivalis W50, W83, ATCC 33277, and A7A1-28 were used in this study. For growth, the cells were plated to enriched Trypticase soy agar or were grown in 2.1% (wt/vol) Mycoplasma broth (BBL, Becton Dickinson, Cockeysville, Md.) supplemented with 5 ptg (wt/vol) of heme per ml. All cultures were incubated in a Coy anaerobic chamber (85% N2, 10% H2, and 5% C02) maintained at 37°C. Cultures were incubated for 24 h or for times appropriate for the experimental design and were harvested and fractionated as described below. Escherichia coli HB101 was used as a hemolysin-negative control. Cell fractionation. For localization of the P. gingivalis hemolysin, cultures were grown, harvested by centrifugation, and washed twice with 3 mM sodium citrate-0.9% NaCl buffer (pH 6.8) (NCN buffer). Cell envelope, outer membrane vesicles, spent growth supernatant, and solublevesicle supernat...

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Burkholderia pseudomallei and Melioidosis: Be Aware in Temperate Area

Yabuuchi

Arakawa

1993

Microbiology and Immunology

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Toxic Lysolipoid: Isolation from Pseudomonas pseudomallei

Cited by 6 publications

References 15 publications

Characterisation of haemolytic activity fromAeromonas caviae

Characterisation of haemolytic activity fromAeromonas caviae

Hemolytic activity in the periodontopathogen Porphyromonas gingivalis: kinetics of enzyme release and localization

Burkholderia pseudomallei and Melioidosis: Be Aware in Temperate Area

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