Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.3 (phospholipase C)
 18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Experiments were carried out to determine whether immunization of female rabbits with highly purified staphylococcal alpha- or beta-toxins would protect them against intramammary challenge with staphylococci. High circulating anti-alpha-toxin titers reduced the lethal hemorrhagic edematous form of the disease ("blue-breast") produced by strains BB and Compton 201 to a localized chronic abscess form. No such protection was afforded by high anti-beta-toxin titers. Immunization with alpha- or beta-toxins produced no change in the clinical picture of the disease produced by CN.6708, a strain of Staphylococcus responsible for a natural outbreak of abscess-type rabbit mastitis. From these experiments it would appear that alpha-toxin is a key antigen in the blue-breast form of rabbit mastitis. Since the abscess form of the disease was not prevented by immunization with either alpha- or beta-toxin, other virulence factors must be acting to produce this more localized disease.
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PMID:Effect immunization with highly purified alpha- and beta-toxins on staphylococcal mastitis in rabbits. 56 Oct 34

A stock strain of Staphylococcus aureus of mastitis origin, characterized by alpha-, beta-, and delta-toxins, was used to produce chronic mastitis of 20 to 300 days' duration in 6 lactating mammary quarters of 4 cows. Early acute Streptococcus agalactiae mastitis was produced in 1 additional mammary quarter of 1 cow. Equine anti-bovine leukocyte serum (EABLS) was administered to all cows by continuous intravascular drip for 12 to 32 hours. Neutropenia in blood and partial depletion of neutrophil reserve in bone marrow were produced. Chronic subclinical staphylococcal mastitis in 2 quarters of 1 cow changed to gangrenous mastitis by the 40th hour after EABLS administration and led to death of the cow. The disappearance of neutrophil leukocytes from the milk was followed by uninhibited multiplication of S aureus. Probably, staphylococcal leukocidins accelerated the destruction of neutrophils in the milk as S aureus multiplication became intensified. In another quarter of the same cow that was infected with Str agalactiae, neutrophil leukocytes were present in milk as long as 3 days after their disappearance from blood and bone marrow. This may give some indication of the extravascular life-span of the neutrophil in the udder in mastitis. The 2nd cow died at the 16th hour from the start of EABLS administration and at a time when gangrenous mastitis was in the initial stages of development. The S aureus-infected quarters of the 2 remaining cows did not become gangrenous. Administration of EABLS to these 2 cows did not significantly reduce the numbers of neutrophil leukocytes entering the milk of the 3 S aureus-infected quarters. It is concluded that continuous diapedesis of neutrophil leukocytes into the milk in chronic staphylococcal mastitis protects the gland against the development of gangrenous mastitis in the presence of a strain of S aureus capable of alpha-toxin production.
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PMID:Conversion of chronic staphylococcal mastitis to acute gangrenous mastitis after neutropenia in blood and bone marrow produced by an equine anti-bovine leukocyte serum. 94 15

Mutants of Staphylococcus aureus which fail to express alpha-toxin (Hly), beta-toxin (Hlb), or both have been constructed by site-specific mutagenesis. The virulence of the mutants was compared with that of wild-type toxigenic strains by intramammary inoculation of lactating mice. A bovine strain, M60, and a laboratory strain, 8325-4, caused acute mastitis and death within 48 h for 60% of the mice inoculated. Animals inoculated with Hly mutants also developed acute mastitis, but no deaths occurred. Comparisons of Hly- or Hlb-positive strains with the double mutation Hly Hlb showed that both toxins led to a significantly higher recovery of S. aureus from the gland 48 h postinfection. Histopathological examination of mammary glands showed that phagocytosis of bacteria occurred irrespective of toxigenicity, but toxigenic strains, particularly those which were Hly+, continued to multiply, invaded the interalveolar tissues, and produced severe lesions. Stimulation of an inflammatory response by inoculation of the mammary gland with endotoxin prior to challenge with S. aureus reduced recovery of the bacteria 10- to 100-fold and, under these conditions, neither alpha-toxin nor beta-toxin contributed significantly to growth and survival.
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PMID:Roles of alpha-toxin and beta-toxin in virulence of Staphylococcus aureus for the mouse mammary gland. 274 56

Effects of bacterial virulence factors on bovine mammary cell structure and function are not well defined. In this study, we evaluated the influence of specific bacterial virulence factors on proliferation of a bovine mammary epithelial cell line. The MAC-T cells were cultured in the presence of medium only, Staphylococcus aureus alpha-toxin, Staph. aureus beta-toxin, Escherichia coli endotoxin, Streptococcus uberis capsule, or hyaluronidase. Cells were cultured in the presence of virulence factors for 48 h at 37 degrees C. The MAC-T cell proliferation was inhibited by all concentrations of endotoxin and alpha-toxin and by most concentrations of hyaluronic acid capsule and hyaluronidase > 7.8 micrograms/ml. Staphylococcus aureus beta-toxin had no effect on MAC-T cell proliferation. Virulence factors produced by mastitis pathogens may influence mammary epithelial cell proliferation in vivo, which could be important during the periparturient period, when mammary tissue undergoes rapid differentiation and growth.
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PMID:Proliferation of a bovine mammary epithelial cell line in the presence of bacterial virulence factors. 783 83

This study was conducted to evaluate the antibody levels of alpha-toxin, capsular polysaccharides (CPS) and fibronectin-binding protein (FnBP) in rabbits immunized with an experimental vaccine against Staphylococcus aureus and to develop the bovine mastitis subunit vaccine in the future. Enzyme immunoassay was used for detection of IgG antibodies against staphylococcal CPS, alpha-toxin and FnBP. The levels of specific antibodies against CPS, alpha-toxin and FnBP in immunized rabbits were significantly increased after first immunization compared with control animals (p<0.05). Of three antigen used in vaccine, immunogenicity of CPS was relatively lower, compared with those of alpha toxin and fibronectin binding protein. Numbers of S. aureus in blood of immunized groups were lower than those of control group after bacterial challenge. But the bacterial numbers among immunized groups were not significantly different. S. aureus counts in excised organs were significantly lower in all immunized rabbits than in PBS-control group (p<0.05). The present study showed that alpha-toxin, capsular polysaccharide and fibronectin binding protein included in a subunit vaccine were protective.
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PMID:Immunogenicity of alpha-toxin, capsular polysaccharide (CPS) and recombinant fibronectin-binding protein (r-FnBP) of Staphylococcus aureus in rabbit. 1053 4

To evaluate clinical effects of autogenous toxoid-bacterin treatment for Staphylococcus aureus subclinical mastitis in lactating cows, 22 cows which had at least one S. aureus infected quarter were selected from among cows at a S. aureus prevalent dairy farm. Eleven cows were injected with their own autogenous toxoid-bacterin and the others were maintained as non-injected control. In the toxoid-bacterin injected group, 27% of infected quarters were cured during the 12-week trial, compared to 5% in the control group. New intramammary infections with S. aureus were only detected in 3 quarters of the control group. Mean IgG antibody titer against S. aureus somatic antigens and alpha-toxin in serum and milk were significantly increased in the toxoid-bacterin injected group (p<0.05) and remained higher than those of the control group which showed no significant changes (p<0.05). In contrast to the control group, from 3 weeks after the second injection of the toxoid-bacterin injected group, mean S. aureus cfu/ml in milk samples from injected quarters with S. aureus was significantly decreased until the end of the study (p<0.05). In the toxoid-bacterin injected group, significant decreases of mean SCC were detected from milk samples from infected quarters with S. aureus from week 7 to week 10 (p<0.05). These data show that autogenous toxoid-bacterin treatment against S. aureus subclinical mastitis in lactating cows may increase the cure rate of the infections, reduce the severity of the infections and also prevent occurrence of the new infections.
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PMID:Effects of autogenous toxoid-bacterin in lactating cows with Staphylococcus aureus subclinical mastitis. 1099 85

Clinical samples (n=725) were collected from bovines (n=243) which were positive for mastitis using the California mastitis test (CMT) and somatic cell count (SCC). The clinical samples comprising blood (n=239), milk (n=243), and faecal swabs (n=243) were examined for the presence of pathogenic Listeria spp. Isolation of the pathogen was done using selective enrichment in University of Vermont Medium and plating onto Dominguez-Rodriguez isolation agar. Confirmation of the isolates was based on biochemical tests and Christie, Atkins, Munch-Petersen (CAMP) test followed by pathogenicity testing. Pathogenicity of the isolates was tested by phosphatidylinositol-specific phospholipase C (PI-PLC) assay as well as in vivo tests namely, chick embryo and mice inoculation tests. The isolates were subjected to PCR assay for five virulence-associated genes, plcA, prfA, hlyA, actA and iap. Listeria spp. were isolated from 12 (1.66%) samples. Of these 4 (0.55%) and 1 (0.14%) were confirmed as Listeria monocytogenes and Listeria ivanovii, respectively. L. monocytogenes and L. ivanovii were recovered from milk samples (2) and faecal (3) of mastitic cattle (3) and buffaloes (2). L. monocytogenes recovered from the milk of mastitic cattle and L. ivanovii from the faecal swab of buffalo turned out to be pathogenic. However, the remaining three hemolytic isolates exhibiting positive CAMP test turned out to be negative in PI-PLC assay, chick embryo and mice inoculation. L. monocytogenes and L. ivanovii isolates characterized as pathogenic by PI-PLC assay and in vivo pathogenicity tests were found to possess all the five virulence-associated genes and three genes, plcA, prfA and actA respectively. The remaining three hemolytic but non-pathogenic L. monocytogenes isolates were negative for plcA by PCR. It seems that the plcA gene and its expression (in the PI-PLC assay) have an important role as virulence determinants in pathogenic Listeria spp. In conclusion, the PI-PLC assay and virulence genes targeted PCR (plcA, prfA and hlyA genes for L. monocytogenes and plcA, prfA and actA genes for L. ivanovii) hold a good promise as rapid and reliable in vitro alternatives to in vivo pathogenicity tests.
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PMID:Detection of multiple virulence-associated genes in Listeria monocytogenes isolated from bovine mastitis cases. 1697 71

Bovine mastitis remains the largest hazard in the global dairy industry and has facilitated the development of various therapeutic strategies. Silver is a well-known disinfectant that is widely used in the treatment of clinical disease. In this study, we separated bovine mammary gland epithelial cells (BMEC) using an enzyme probe. We also examined safe concentrations for the application of silver ions in bovine mastitis, particularly in cases induced by Staphylococcus aureus. S. aureus-derived alpha-toxins induced cell damage through DNA fragmentation, reactive oxygen species (ROS) generation, and the dissipation of mitochondrial transmembrane potential (MTP) in BMEC. Silver ion treatment doses of lower than 2 ppm did not induce BMEC damage, but silver ion concentrations greater than 4 ppm was accompanied by DNA fragmentation. Furthermore, silver ions doses below 2 ppm inhibited alpha-toxin-induced cell damage through the reduction of ROS generation. Recognizing this, it demonstrate that low doses of silver ions inhibit alpha-toxin-induced BMEC damage and suggest that silver ions may be a potentially beneficial treatment against bovine mastitis, particularly in cases induced by S. aureus.
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PMID:Silver ion treatment of primary cultured bovine mammary gland epithelial cell (BMEC) damage from Staphylococcus aureus-derived alpha-toxin. 2001 51