共查询到20条相似文献,搜索用时 15 毫秒
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H C Neu 《Journal of general microbiology》1969,57(2):215-220
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The lysis of micro-organisms by lysozyme and related enzymes 总被引:1,自引:0,他引:1
SALTON MR 《Journal of general microbiology》1958,18(2):481-490
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Summary The influence of lysozyme and salts on the growth of the microflora of shrimp was investigated. It was found that lysozyme at concentrations up to 150 g/ml could retard microbial growth in nutrient broth at 28°C. Growth of shrimp microflora was not affected much at low concentrations (0.05% and 0.1%) of EDTA but was totally inhibited in the presence of 0.5% Na2EDTA. No growth was discernible using concentrations of 50 g/ml lysozyme and 0.02% Na2EDTA, either in nutrient broth or in 2% shrimp homogenate. 相似文献
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The biological role of death and lysis in biofilm development 总被引:1,自引:0,他引:1
Bayles KW 《Nature reviews. Microbiology》2007,5(9):721-726
Recent studies have revealed that the regulated death of bacterial cells is important for biofilm development. Following cell death, a sub-population of the dead bacteria lyse and release genomic DNA, which then has an essential role in intercellular adhesion and biofilm stability. This Opinion focuses on the role of regulated cell death and lysis in biofilm development and provides a functional comparison between bacterial programmed cell death and apoptosis. The hypothesis that the differential regulation of these processes during biofilm development contributes to the antibiotic tolerance of biofilm cells is also explored. 相似文献
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Lankas GR Cukierski MA Wise LD 《Birth defects research. Part B, Developmental and reproductive toxicology》2004,71(3):111-123
The role of maternal toxicity in lovastatin-induced developmental toxicity in rats was examined in a series of studies. The first study administered lovastatin at 100, 200, 400, or 800 mg/kg/day (mkd) orally to mated rats from Gestation Day (GD) 6 through 20. Maternal toxicity was observed as transient dose-related body weight losses at the initiation of dosing; there were also deaths and/or morbidity at 400 and 800 mkd. These toxicities occurred in conjunction with forestomach lesions. Mean fetal weights were decreased in all groups (-5 to -16%), and the incidence of skeletal malformations, variations, and incomplete ossifications was increased. The 2 highest doses produced the most severe maternal and developmental effects. Using the same dosages, the second study avoided gestational maternal weight losses and morbidity by starting treatment 14 days before mating with dosing continued to GD 20. There were transient dose-related body weight losses after the start of dosing and deaths in the 400- and 800-mkd groups; however, there was no evidence of maternal toxicity during gestation. Developmental toxicity was evident only as slight, but generally significant (p< or =0.05) decreases in mean fetal weights in groups given > or =200 mkd (-2 to -5%). Significantly, no skeletal abnormalities were observed. A third study administered the pharmacologically active metabolite of lovastatin subcutaneously at dose levels that matched oral maternal drug exposures. In the high-dose group, maternal weight gain and mean fetal weight were slightly decreased but there were no treatment-related skeletal abnormalities. Finally, a series of toxicokinetic studies assessed whether the 2 different developmental toxicity profiles were due to differences in drug exposure between the developmentally toxic and non-toxic dosing regimes. The data showed that groups with no skeletal abnormalities had maternal and embryonic/fetal drug concentrations similar to or even greater than the groups with fetal abnormalities. These results indicate that fetal skeletal abnormalities observed at lovastatin dose levels > or =100 mkd are not due to a direct teratogenic effect, but are the result of excessive maternal toxicity, which most likely involves a nutritional deficiency associated with forestomach lesions and reduced maternal food intake. 相似文献
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The D95°C value of Bacillus thuringiensis spores plated in the presence of lysozyme increased from 3.0 min to 3.6 min by post-treatment of heat-injured spores with 50mm EDTA. In the case of Bacillus alvei and Bacillus polymyxa spores D-values decreased from 4.9 to 4.3 min and from 4.7 to 4.1 min respectively. Post-treatment of heat-injured spores treated with alkaline thioglycollate increased D95°C values of Bacillus alvei from 4.2 to 5.3 min, B. thuringiensis 3.6 to 4.7 min, and Bacillus polymyxa from 4.2 to 5.0 min when spores were plated in the presence of lysozyme. Electron micrographs of heat-injured B. alvei spores treated with sodium thioglycollate indicated that the coat layers of the treated spores were granulated and less intact than the control spores. 相似文献
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The presence of divalent (Mg2+ ) ions greatly reduced the lysis of Pseudomonas aeruginosa strain G48 in a system at pH 7·8 or 9·0 consisting of ethylenediamine tetraacetic acid (EDTA), lysozyme and tris. Similar reductions in lysis occurred when EDTA was replaced by nitrilotriacetic acid, sodium citrate or sodium polyphosphate. The effect depended on the cation concentration. Mg2+ may replace cations removed from the outer membrane, or may effectively remove the permeabilizer from the system. The results suggest that the permeabilizing activity associated with these agents against this organism has a common basis in affecting the outer membrane. 相似文献
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Ascorbic acid given orally to lead exposed rats has similar chelating properties as equimolar amounts of parenterally administered EDTA. Ascorbic acid in combination with EDTA is more than twice as effective as either chelating agent given alone and the combination is particularly effective in removing lead from the central nervous system. 相似文献
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Under the conditions employed, the rate of clearing of washed cell suspensions of Micrococcus lysodeikticus, measured photometrically, is nearly proportional to enzyme concentration and nearly inversely proportional to the initial concentration of cells. With a given amount of lysozyme (usually 1.5 μg./ml.) the density of a cell suspension decreases exponentially with time, until it is reduced to between 20 and 40% of that at the start, followed by a decreasing rate of clearing. Under increased hydrostatic pressures of 4000 and 8000 p.s.i., respectively, the rate of clearing is faster than at normal pressure at various pH's between 5.65 and 8.70, at 35 °C. 相似文献
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Tributyltin inhibited the growth of cells in concentration dependent manner. The inhibitory effect of tributyltin on E. coli was enhanced in the presence of metal ion chelator, EDTA. This was due to EDTA induced increase of permeability of bacterial cell envelope to tributyltin. In case of EDTA treated cells the rate of uptake of tributyltin was more pronounced as compared to control. 相似文献
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The role of calcium in salt toxicity 总被引:29,自引:11,他引:18
Z. RENGEL 《Plant, cell & environment》1992,15(6):625-632
Salt toxicity comprises osmotic and ionic components both of which can severely affect root and shoot growth. Uptake of Na+ across the plasma membrane is very fast resulting in physiological effects on extracellular as well as intracellular sites. Sodium reduces binding of Ca2+ to the plasma membrane, inhibits influx while increasing efflux of Ca2+, and depletes the internal stores of Ca2+ from endomembranes. These changes in the cell Ca2+ homeostasis are suggested here to be the primary responses to salt stress that are perceived by root cells. Salt would almost instantly reduce the amount of Ca2+ being transferred to the leaf cells, with Ca2+ activity dropping and Na+ activity rising in the apoplasm of leaf cells. This Ca2+ signal would be transported to leaves together with, if not preceding, the signal of limited water supply. Hormonal signals are likely to be secondary in nature and caused by the Na+-related disturbance of the root cell Ca2+ homeostasis. Ameliorative effects of supplemental Ca2+ on salt stress are exerted through preventing Na+-related changes in the cell Ca2+ homeostasis. 相似文献