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1.
Appl Environ Microbiol ; 65(7): 3258-60, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10388733

RESUMO

The effects of 1-[(E)-2-(2-methyl-4-nitrophenyl)diaz-1-enyl]pyrrolidine-2-carboxy lic acid (LY29) and diphenyliodonium chloride (DIC) on the degradation of protein to ammonia were determined in a mixed rumen microbial population taken from sheep on a grass hay-concentrate diet. Both compounds decreased NH3 production by inhibiting deamination of amino acids. LY29, but not DIC, inhibited growth of the high-activity ammonia-producing species, Clostridium aminophilum and Clostridium sticklandii.


Assuntos
Azetidinas/farmacologia , Bactérias/efeitos dos fármacos , Compostos de Bifenilo/farmacologia , Endopeptidases/metabolismo , Oniocompostos/farmacologia , Prolina/análogos & derivados , Proteínas/metabolismo , Pirrolidinas/farmacologia , Rúmen/microbiologia , Ração Animal , Animais , Bactérias/metabolismo , Clostridium/efeitos dos fármacos , Clostridium/crescimento & desenvolvimento , Clostridium/metabolismo , Desaminação , Inibidores Enzimáticos , Poaceae , Prolina/farmacologia , Rúmen/metabolismo , Ovinos
2.
Br J Nutr ; 78(2): 237-49, 1997 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9301414

RESUMO

Samples and extracts of foliage from African multipurpose trees were screened for their effects on rumen protozoa and bacteria with a view to predicting their safety as feed supplements and for identifying species with potential antiprotozoal activity. The species tested were Acacia aneura, Chamaecytisus palmensis, Brachychiton populneum, Flindersia maculosa, Sesbania sesban, Leucaena leucocephala and Vernonia amyedalina. Antimicrobial effects were mild except for S. sesban, which was highly toxic to rumen protozoa in vitro, and A. aneura, which was toxic to rumen bacteria. The antiprotozoal factor in S. sesban was apparently associated with the fraction of the plant containing saponins. When S. sesban was fed to sheep, protozoal numbers fell by 60% after 4 d, but the population recovered after a further 10 d. In vitro experiments demonstrated that washed protozoa from later times were no more resistant to S. sesban than on initial exposure, suggesting that other micro-organisms, probably the bacteria, adapted to detoxify the antiprotozoal agent. Thus S. sesban may be useful in suppressing protozoa and thereby improving protein flow from the rumen, but only if the bacterial metabolism of the antiprotozoal factor can be avoided.


Assuntos
Antibacterianos/administração & dosagem , Antiprotozoários/administração & dosagem , Rúmen/microbiologia , Rúmen/parasitologia , Ovinos/microbiologia , Ovinos/parasitologia , Árvores , África , Animais , Bactérias/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Eucariotos/crescimento & desenvolvimento
4.
Trop Anim Health Prod ; 20(1): 52-6, 1988 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3354060

RESUMO

Clinical cases of both Zn and Cu deficiencies are reported in a cattle farm in Kordofan Region of the Sudan after drought. The animals showed general weakness, stunted growth, infertility, parakeratosis and achromotrichia. There was macrocytic hypochromic anaemia and low Cu and Zn concentrations in sera. The condition was more prevalent in zebu-Friesian crosses than the local breeds. Drought and marginal or low Cu and Zn content in pasture may be the predisposing factors.


Assuntos
Doenças dos Bovinos/epidemiologia , Cobre/deficiência , Zinco/deficiência , Ração Animal , Animais , Bovinos , Feminino , Sudão , Tempo (Meteorologia)
6.
Vet Res Commun ; 8(1): 65-7, 1984 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-6719830

RESUMO

Goats that had been inoculated with the causal organism of contagious caprine pleuropneumonia and treated, within a few days, with oxytetracycline or tylosin, were less severely affected than infected, untreated control goats. However, 20% of treated cases remained infective and were, presumably, capable of transmitting the infection.


Assuntos
Cabras , Leucomicinas/uso terapêutico , Infecções por Mycoplasma/veterinária , Pleuropneumonia Contagiosa/tratamento farmacológico , Tetraciclina/uso terapêutico , Animais , Pleuropneumonia Contagiosa/mortalidade , Pleuropneumonia Contagiosa/patologia , Sudão , Tilosina
7.
Virology ; 108(2): 286-96, 1981 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-18635030

RESUMO

Virions of southern bean mosaic virus (SBMV) show two distinct sensitivity patterns upon heating. Infectivity loss and capsid denaturation occur concurrently if virions are exposed at 50-55 degrees in 0.1 M sodium phosphate buffer, pH 7.5, or 0.1 M glycine-phosphate buffer, pH 9.0. Contrastingly, virions are inactivated without any detectable capsid damage at 65-70 degrees in 0.1 M sodium phosphate buffer, pH 6.0, 0.1 M Tris-HCI buffer, pH 7.5, or 0.1 M glycine-NaOH buffer, pH 9.0. Heat treatment causes no genomic degradation in these two situations; the divergent sensitivity of virions is due, apparently, to a differential thermal tolerance of the capsid protein to the buffer components and/or pH. SBMV-RNA isolated from virions inactivated at 65 degrees in 0.1 M Tris-HCl buffer, pH 7.5, possesses low infectivity (1-2%). Observations based upon sucrose gradient sedimentation, temperature: absorbance relationship, and sensitivity to ribonuclease T(1) suggest that such RNA is structurally more compact and stable relative to that of the RNA from the nonheated virions. Neither the capsid protein nor the genome protein plays a direct role in the temperature-induced structural stabilization of SBMV-RNA in situ. If treated with 8 M urea, 50% formamide or exposed at 55 degrees , the infectivity of RNA from the heat-inactivated SBMV is restored and is comparable to that of the RNA isolated from the nonheated virions. The observed mode of SBMV thermal inactivation, i.e., stabilization of RNA structure in situ, is unique among the viruses. Furthermore, these results suggest that the ability to initiate infection depends upon the secondary structure of the SBMV genome.

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