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排序方式: 共有1074条查询结果,搜索用时 46 毫秒
1.
2.
J Pokorny 《Journal of hygiene, epidemiology, microbiology, and immunology》1988,32(3):361-366
Survival and virulence of salmonellae in drinking and surface waters were tested in a series of model experiments using suspensions of fresh strains of Salmonella enteritidis as a tester strain. Environmental conditions in surface water, modeled by the addition of increasing amounts of municipal sewage, were simulated to have the organic pollution load equivalent COD to 5.3-9.7-15.2 mg O2/l and the coliform counts ranging from 2 X 10 to 2 X 10(3) per ml water. The experiments were carried out at 4 degrees C and 20 degrees C, i.e. at temperatures simulating the two crucial points of the year-round thermal characteristics of water in the external environment. Suspensions of S. enteritidis in water had the initial density ranging between 1 X 10(2) and 1 X 10(4) (per ml, tests for virulence were carried out in the guinea pig eye (conjunctivitis reaction). Time of S. enteritidis survival in the drinking water free of organic pollutants was directly affected by the initial density of strain and indirectly by water temperature, in surface water the most significant variable turned out to be the degree of organic pollution: the time of survival clearly tended to shorten as the complex of organic pollutants in water increased. At the highest degree of organic pollution (COD concentration 15.2 mg per ml) S. enteritidis survival was restricted to less than 24 h whereas in drinking water it could reach up to 30 days. The survival time was always identical with the time of virulence persistence. 相似文献
3.
Dieter Ehlers Ina Sakowski Werher Mohrig 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1989,159(4):481-489
Summary The high affinity of granulocytes of guinea pig and man to glass surfaces is modified by serum. Native serum contains both an adherence-promoting activity, which is related to complement, and components which reduce the adhesiveness of granulocytes. These components are stable at 56°C for 30 min and are tightly bound to the glass surface. -Lipoproteins are candidates for this adherence reducing ability of serum. Adherence promotion by native serum is mediated by coating the glass surface with C3b/C3bi. Human granulocytes from the peripheral blood adhered to glass surfaces coated by native human or guinea pig serum with C3b/C3bi to almost the same extent as in the presence of native serum, but on guinea pig granulocytes elicited in the peritoneal cavity, a cell surface metalloproteinase degraded the C3b/C3bi, thus reducing the adhesiveness of these cells. This proteinase was inhibited by MgEDTA, DTT, and 1,10-phenanthroline, whereby the high adhesiveness of granulocytes was restored to C3b/C3bi-coated glass.Abbreviations
BA
benzamidine hydrochloride
-
BTS
Bacillus thuringiensis subtoxicus
-
DTT
dithiothreitol
-
EAC
-amino-caproic acid
-
gp
guinea pig
-
LDL
low density lipoproteins
-
SEM
scanning electron microscopy 相似文献
4.
Summary A trypsin-like proteinase was isolated from Streptomyces rimosus culture filtrates obtained from an oxytetracycline production process. The isolation procedure includes ultrafiltration, chromatography on CM-Sephadex, AH-Sepharose and CM-cellulose and gives a homogeneous protein with 19% yield. The enzyme is an anionic trypsin (Mr 28 000, pI 4.5), is stable from pH 4.5 to 9 and up to 40°C, and contains three disulphide bridges, three histidines and three methionines per molecule. At its pH optimum (pH 8.4–8.8) it splits peptide, ester and arylamide bonds of arginine in the endo-position and, to a smaller extent, in the exo-position. Like other streptomycete trypsins, it is a more efficient catalyst than bovine trypsin and has a relative preference for peptide-arylamides, N-benzyloxycarbonyl-l-norleucyl-l-prolyl-l-arginine-p-nitroanilide being by far its best substrate. 相似文献
5.
Jessica E. Hoogendijk Gerard W. Hensels Ina Zorn Linda Valentijn Emiel A. M. Janssen Marianne de Visser David F. Barker Bram W. Ongerboer de Visser Frank Baas Pieter A. Bolhuis 《Human genetics》1991,88(2):215-218
Summary Recently, it has been shown that Charcot-Marie-Tooth disease type 1a (CMT1a) is linked with a duplication of a DNA segment that is detected by probe VAW409R3, and that is located on chromosome 17p11.2. Here, we show that this duplication also contains VAW412R3a, but not A10-41 and EW503. Accounting for the duplication in recombination analysis, we found recombinants between CMT1a and EW301 and EW502, but not with A10-41, VAW409R3, and VAW412R3. Using pulsed-field gel electrophoresis analysis, we estimated the minimal size of the duplicated region in CMT1a patients to be 1100 kb. 相似文献
6.
Mycotoxins and Fusarium spp. associated with infected ears of corn in Minnesota. 总被引:1,自引:1,他引:0 下载免费PDF全文
H K Abbas C J Mirocha R A Meronuck J D Pokorny S L Gould T Kommedahl 《Applied microbiology》1988,54(8):1930-1933
Five Fusarium species were isolated from the grain of dent corn (Zea mays) selected from 20 of 32 damaged fields in 10 counties in Minnesota on the basis of hyphal growth visible on kernels in the field. Three mycotoxins were identified in the infected ears: zearalenone, deoxynivalenol, and 15-acetyl-deoxynivalenol. This is the first report of the presence of 15-acetyl-deoxynivalenol on corn ears in the field prior to harvest and in combination with deoxynivalenol and zearalenone. Ninety-nine cultures were selected from colonies growing from kernels on an agar medium; 30% of the cultures were F. graminearum, 23% were F. subglutinans, 20% were F. moniliforme, 14% were F. oxysporum, and 12% were F. proliferatum. 相似文献
7.
Lj. Vitale M. Renko B. Lenarčič V. Turk M. Pokorny 《Applied microbiology and biotechnology》1986,23(6):449-455
Summary A leucine aminopeptidase was purified to homogeneity fromStreptomyces rimosus culture filtrates, which are waste broth of oxytetracycline bioproduction process. Purification procedure includes ultrafiltration
and chromatography on CM-Sephadex, AH-Sepharose and FPLC Mono S column.
The enzyme is a monomer with molecular weight of 27,500 Daltons and pI of 7.3, stable in broad pH range and up to 70°C. It
is a metallo enzyme dependent on Ca2+ ions for its full activity. By its specificity it is a true aminopeptidase active on amino acid amide, arylamide, peptide
and ester bonds. The hydrolysing activity shows preference for leucine at the N-terminal position of substrates, also acts
on aromatic acids and methionine, but does not release glycine, proline, acidic amino acids orD-amino acid residues. 相似文献
8.
D Keglevi? B Ladesi? O Hadzija J Tomasi? Z Valinger M Pokorny R Naumski 《European journal of biochemistry》1974,42(2):389-400
9.
Scavenging of Hydrogen Peroxide in the Endosperm of Ricinus communis by Ascorbate Peroxidase 总被引:6,自引:0,他引:6
The fat-storing endosperm of Ricinus communis L. was found tocontain an ascorbate peroxidase (EC 1.11.1.11
[EC]
), which is nearlyas active as catalase (EC 1.11.1.6
[EC]
) in degradation of hydrogenperoxide (H2O2) at its physiological concentrations. This ascorbateperoxidase probably functions together with monodehydroascorbatereductase (EC 1.6.5.4
[EC]
) or dehydroascorbate reductase (EC 1.8.5.1
[EC]
)and glutathione reductase (EC 1.6.4.2
[EC]
) to remove the H2O2 producedduring the transformation of fat to carbohydrate in the glyoxysomes.The activities of these enzymes as well as the content of ascorbateand glutathione increase parallel to the activities of glyoxysomalmarker enzymes during the course of germination. Inhibitionof catalase by aminotriazole results in increases of the ascorbateperoxidase activity and of the glutathione content. All fourenzymes are predominantly localized in the cytosol of the Ricinusendosperm with low activities found in the plastids and themitochondria. The results suggest, that the ascorbate-dependentH2O2 scavenging pathway, which has been shown to be responsiblefor the reduction of photosynthetically derived H2O2 in thechloroplasts, operates also in the Ricinus endosperm. (Received June 5, 1990; Accepted July 31, 1990) 相似文献
10.