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P Gouet

Publications and source records attributed to P Gouet.

12 recordsLinked to original sources
PubMed1979

[Induction and repression of the collagenase synthesis in Acinetobacter sp].

The synthesis of collagenase in Acinetobacter sp. was found to be inducible by denatured collagen and by its high molecular weight fragments. The presence in the inducer of part of the tertiary structure appear to be indispensable. On the other hand, an addition of Casamino acids, meat protein hydrolysate, or a mixture of amino acids with a similar composition to gelatin does not stimulate collagenase synthesis. Enzyme production was severely repressed in the early phase of growth by glucose, arabinose, and ribose, single amino acids, proline, hydroxyproline, alanine, glutamic acid or casein acid hydrolysate. A mechanism of repression similar to catabolite repression was involved in the phenomenon caused by carbohydrates. However, the fact that cyclic adenosine 3'5-monophosphate did not overcome the repression caused by amino acids or Casamino acids, in contrast to classical catabolite repression, suggests that these two forms of repression may be distinct.

Acinetobacter↗
PubMed1979

[Purification and physico-chemical properties of collagenase synthesized by a bacterium of the type Acinetobacter sp].

The Acinetobacter spec collagenase has been almost completely purified. This enzyme is a true collagenase the activity of which is high on collagen. The enzyme is active on insoluble collagen, gelatin and the synthetic Pz-peptide, but has no proteolytic activity on casein or bovine serum-albumin. The collagenase was obtained on a simple medium with gelatin and yeast extract. The enzyme was purified by (NH4)2SO4 precipitation. DEAE cellulose column chromatography, Sephadex G 200 gel-filtration. The molecular weight of the enzyme was found to be 102 000 daltons, and its isoelectric point was found to be 7,7 +/- 0,2. The optimum pH and temperature for insoluble collagen hydrolysis were 7.6 and 37 degrees C, respectively; so, this collagenase corresponds to true collagenase. Hydrolysis of Pz-peptide is activated by Ca2+ and inhibited by metal ions (Cu2+, Fe3+, Zn2+, Pb2+, Hg2+). EDTA and o-phenanthroline induced a very significant reduction in enzyme activity. Iodoacetate and p-CMB induced a slight reduction in enzyme activity only at high concentrations (10-2M). The collagenase is most stable for temperatures less than or equal to 50 degrees C.

Acinetobacter↗
PubMed1978

The experimental production of diarrhoea in colostrum deprived axenic and gnotoxenic calves with enteropathogenic Escherichia coli, rotavirus, coronavirus and in a combined infection of rotavirus and E. coli.

We attempted to produce diarrhoea experimentally in the newborn calf by orally injecting 17 colostrum-deprived calves with two serotypes of Escherichia coli Ent+ K99+, a rotavirus and a coronavirus. With E. coli alone, a dose of 2 x 10(8) bacteria administered 24 hours after birth causes a mild attack of diarrhoea, whereas 1 x 10(10) bacteria leads to dehydration and death. An inoculation of rotavirus is followed by diarrhoea which always contains large quantities of rotavirus. These animals were anorectic for a time, but none was dehydrated or died. With coronavirus, there were large quantities of watery diarrhoea, which led to dehydration and death. The inoculation of rotavirus, not lethal in itself, followed by a similarly non lethal inoculation of E. coli in doses of 3 x 10(8) to 2 x 10(9) led to dehydration and death. The authors conclude that dehydration and death of the animal can caused by large doses of E. coli or coronavirus or by two non-lethal doses of rotavirus and E. coli administered one after the other.

Animals↗
PubMed1978

Scanning electron microscopy of abomasium and intestine of gnotoxenic calves infected either with rotavirus, coronarivus or enteropathogenic Escherichia coli or with rotavirus and E. coli.

Neonatal calf diarrhoea induced with several agents of infection was studied by scanning electron microscopy. In a gnotoxenic calf infected with E. coli K99+ Ent+, slight lesions of the small intestine were observed and desquamation or puffiness of microvilli occurred. In rotavirus-infected calves, the abomasum was covered with abudant mucous film and appeared to be desquamated. In the small intestine, no desquamation of epithelium was observed. Inoculation of the rotavirus and E. coli induced severe diarrhoea. The whole digestive tract, even the abomasum and colon, was eroded. Coronavirus induced marked lesions in all levels of the intestine. These results demonstrate unequivocally the pathogenic properties of the three infectious agnets, the synergistic effect of E. coli and rotavirus. Furthermore, the importance of the abomasum in neonatal diarrhoea is emphasized.

Abomasum↗
PubMed1978

Specific protection by colostrum from cows vaccinated with the K 99 antigen in newborn calves experimentally infected with E. coli Ent+ K99+.

We have measured the protective effect of colostrum of vaccinated cows with the K99 antigen comparatively with the colostrum of non vaccinated cows, in calves receiving at birth 2 liters of colostrum and just after 5 times 10(10) to 1 times 10(11) E. coli Ent+, K99+. The K99 antigen was prepared from E coli B41 (0101:K99:H-) cultured in a fermentor. Cows were vaccinated subcutaneously with 100 mg or 300 mg (wet weight) in emulsion in Freund uncomplete adjuvant 45 and 15 days before parturition. Of 4 calves receiving a colostrum of non vaccinated cows 4 had a diarrhoea, 3 became dehydrated and 2 died. Of 6 calves receiving colostrum of vaccinated cows, 5 were healthy and the 6th calf had a mild diarrhoea for few hours and became again healthy. Control and protected calves excreted E. coli K99+, 24 HOURS AFTER INFECTION. The protection is probably due to K99 antibodies which inhibit adhesion of E. coli K99+ to the intestinal epithelium.

Animals↗
PubMed1978

Development of listeria monocytogenes in monoxenic and polyxenic beef minces.

The objective of this study was to determine the multiplication possibilities of Listeria monocytogenes in beef minces with a defined microflora (gnotoxenic). Selective counts were made for each species and each bacterial association for a period of 17 days after inoculation of the axenic meat. The concentration of L. monocytogenes did not increase, but remained constant in monoxenic meats. Associated with Lactobacillus plantarum, the number of Listeria tended to decrease. Conversely, in association with P. fluorescens, L. monocytogenes definitely multiplied, especially in polyxenic meats, the microflora of which is similar to that of conventional meats. Consequently, it seems that meat might constitute a source of L. monocytogenes infection.

Food Contamination↗
PubMed1977

Blood poisonings at slaughter and their consequences.

Contamination of pig blood by Str. faecium and P. fluorescens realized either through the bleeding knife or through intravenous injection. Bacterial counts made in the organs and muscles showed a large contamination of the organs and a smaller contamination of the muscles. In the case where Str. faecium and P. fluorescens were injected into the blood circulation, only Str. faecium could be re-isolated in muscles and organs. Study of the bactericidal activity of total blood and plasma showed a marked antimicrobial activity against P. fluorescens and a slightly activity against Str. faecium.

Abattoirs↗
PubMed1975

[Mannose dependent horse erythrocyte agglutinin specific to bovine enterotoxic E coli strains].

We show that in enterotoxic or not enterotoxic E. coli strains from various origins, enterotoxic strains of E. coli from calves only agglutin horse red cells in presence of mannose. The haemagglutinins structure, not visible with electron microscope is compatible with presence of fimbriae. It would be K 99 antigen, specific adhesiveness structure for strains from calves.

Agglutinins↗
PubMedDate not supplied

[Attachment of a collagenolytic strain to its substrate (author's transl)].

The bacterial collagenolytic strain Acinetobacter sp. CRZV2 adheres to insoluble collagen fibers when this substrate is introduced into the growth medium. This attachment occurs during the exponential growth. Proteolytic enzymes such as pronase and trypsine activate the adherence of bacterial cells to collagen fibers.

Acinetobacter↗