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1.
越橘属的蓝莓含有酚类物质、有机酸类、花青素类和糖类等生物活性成分。较早研究表明,蓝莓具有抗感染、抗氧化、抗肿瘤等功能,而近年的研究表明蓝莓具有抑菌作用。本文介绍了蓝莓的抑菌活性,分析了蓝莓中的抑菌活性成分,同时概括了蓝莓提取物对各种菌体的抑菌机理。 相似文献
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【背景】美人鱼发光杆菌(Photobacteriumdamselae)是一种海洋条件致病菌,能够引起多种海洋生物和人类疾病。因此,探究美人鱼发光杆菌的生物防治技术具有重要意义。【目的】探究枯草芽孢杆菌(Bacillus subtilis)中bacilosarcin B对美人鱼发光杆菌的抑菌活性及其可能的抑菌机理。【方法】利用高效液相色谱法从枯草芽孢杆菌fmb60发酵液中制备bacilosarcin B,采用分光光度法测定bacilosarcinB对多种致病菌的最小抑菌浓度及其对美人鱼发光杆菌的时间-抑菌曲线。测定bacilosarcin B对美人鱼发光杆菌生物被膜、胞外核酸、蛋白质和胞内碱性磷酸酶含量的影响,结合荧光显微镜、扫描电镜和透射电镜检测美人鱼发光杆菌细胞膜通透性和细胞壁完整性,并研究bacilosarcin B对细菌运动能力和胞内DNA的作用。【结果】Bacilosarcin B对美人鱼发光杆菌最小抑菌浓度为8μg/mL。抑菌机理研究表明bacilosarcin B通过破坏细菌细胞壁和细胞膜的完整性使细胞膜通透性增强,造成细胞内成分渗出。此外,bacilosarcinB还可与... 相似文献
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益生菌产生的细菌素及其功能机制 总被引:2,自引:0,他引:2
细菌素是细菌核糖体合成的具有抑菌活性的小肽.细菌素的产生是益生菌重要的益生特性,它们天然无毒,不仅对食品腐败菌和人体致病菌有很好的抑菌活性,还具有有助益生菌定殖和调节肠道菌群等益生特性.本文综述了益生菌产生的细菌素的种类、条件性合成、益生功能及其作用机理等,以期为深入认识益生菌的益生功能及其作用方式,研究开发对人体有益... 相似文献
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植物精油抑菌活性研究进展 总被引:8,自引:0,他引:8
本文综述了国内外植物精油在农用抑菌活性及抑菌活性成分研究方面所取得的成果。阐述了具有农用抑菌活性的31种植物精油及其抑菌效果,并列举了植物精油中13种具有开发潜力的抑菌活性成分,简要分析了植物精油及其主要活性成分的作用机理。 相似文献
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茶多酚的抗氧化和抑菌活性及其增效剂 总被引:17,自引:0,他引:17
论述了茶多酚的抗氧化和抑菌活性机理,其中起重要作用的是茶多酚分子内的多个酚羟基。在抗氧化过程中,其酚羟基具有供氢体的活性,阻断自由基的链式反应。在抑菌过程中,其酚羟基可与蛋白质分子中的氨基或羧基结合,其疏水性的苯环结构也可与蛋白质发生疏水结合,茶多酚与蛋白质之间的这种多点结合作用阻止了细菌的侵染,使其具有抑菌性。作为增效剂,有机酸、β-胡萝卜紊等能够增强茶多酚的抗氧化性能;壳聚糖、食盐等能够增强茶多酚的抑菌活性.维生素类既能够增强茶多酚的抗氧化性能又能增强其抑菌作用。 相似文献
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为探究蒲公英植酸对沙门氏菌的抑制作用及其抑菌机理。本文利用沉淀法和离子交换法提取蒲公英植酸,滤纸片法分析蒲公英植酸对沙门氏菌(Salmonella)的抑菌作用,倍比稀释法研究蒲公英植酸的最低抑菌浓度。通过分析沙门氏菌的细胞通透性和生长动力学,结合扫描电镜和荧光显微镜研究了蒲公英植酸对沙门氏菌的抑菌机理,表明蒲公英植酸对沙门氏菌具有很好的抑菌能力,其最小抑菌浓度为0.2 mg/mL。而且植酸对沙门氏菌的抑制作用是通过破坏细胞膜达到抑菌的效果,并且植酸浓度越高,抑菌效果越显著。这表明蒲公英植酸可以有效地抑制沙门氏菌生长,其主要是通过破坏菌体细胞膜完整性,增加细胞薄膜的通透性,使细胞内容物外溢达到抑制细菌生长的目的。 相似文献
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植物精油对植物病原菌的抑菌活性研究进展 总被引:1,自引:0,他引:1
《中国野生植物资源》2018,(6)
综述了植物精油对不同植物病原菌的抑菌活性及抑菌活性成分研究方面所取得的成果。阐述了32种植物精油的农用抑菌活性,并分析了植物精油及其主要活性成分的作用机理。 相似文献
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Tran DC Yeh KC Brazeau DA Fung HL 《Biochemical and biophysical research communications》2003,310(2):439-445
Inhalant nitrites are drugs of abuse that have been shown to enhance tumor growth rate in mice and are epidemiologically linked to an increased risk of Kaposi's sarcoma. Because nitrites produce nitric oxide, we hypothesized that their toxicological effects might be partly mediated via regulation of angiogenic factors such as vascular endothelial growth factor (VEGF). Preliminary studies showed that isobutyl nitrite (ISBN) incubation stimulated VEGF protein expression in J774 macrophage cells. C57BL/6 mice exposed to ISBN in air exhibited significant up-regulation of VEGF protein and mRNA in the liver, but not in the lung. Liver mRNA expression of VEGF receptor 2 (VEGFR-2), VEGFR-3, Smad5, and Smad7 was also significantly altered. These results demonstrate that in vivo exposure to an inhalant nitrite results in altered tissue expression of VEGF and its receptors, suggesting that some of its toxicological effects may be mediated partly through a mechanism involving angiogenesis. 相似文献
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Goggins MG Shah SA Goh J Cherukuri A Weir DG Kelleher D Mahmud N 《Mediators of inflammation》2001,10(2):69-73
BACKGROUND: Nitric oxide (NO) production is increased in inflammatory bowel disease (IBD), and measurement of NO metabolites may be useful for monitoring disease activity. AIMS AND OBJECTIVES: To characterise urinary nitrite levels, a stable metabolite of NO, in IBD and to evaluate its potential as a marker of disease activity. METHODS: Twelve-hour urinary nitrites were measured by the microplate assay method in 46 patients with IBD (active; n = 32). Urinary samples from 16 healthy individuals served as controls. RESULTS: Increased levels of urinary nitrites were found in patients with active IBD compared with those with inactive IBD. Twenty-eight out of 32 patients (87.5%) with active IBD had detectable levels of nitrite in their urine as compared with 2/14 (14.3%) patients with inactive IBD. None of the 16 healthy controls had detectable urinary nitrite. Twelve-hour urinary nitrite in active compared with inactive IBD: 5 0.7 versus 0.1+/-0.04 micromol (P < 0.05). There was good correlation between urinary nitrite and some markers of disease activity in IBD such as C-reactive protein and microalbuminuria but not with erythrocyte sedimentation rate. Conclusions: Increased levels of nitrite were detected in urine of patients with active IBD, consistent with increased NO synthesis. This simple assay may be exploited as a potential marker of disease activity in IBD. 相似文献
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Mutagenicity of methyl nitrite in Salmonella typhimurium 总被引:1,自引:0,他引:1
Methyl nitrite was tested for mutagenicity in Salmonella typhimurium TA1535. In the first set of experiments, plated bacteria were exposed to methyl nitrite in desiccators both in the absence and presence of a metabolizing system (S9 from Aroclor-pretreated Sprague-Dawley rats). Initial concentrations from 125 to 500 ppm were tested. In all experiments an increased initial concentration gave an increased mutagenic response. The mutagenic effect in the presence of S9 was similar to that in the absence of S9. Owing to difficulties in dose determinations in this type of experiment it could not be decided, unequivocally, whether the mutagenic effect was caused by methyl nitrite or its hydrolysis products. Experiments were therefore carried out in suspension, and the concentrations of methyl nitrite and inorganic nitrite were determined. Treatments with inorganic nitrite were also carried out under similar conditions. From the results of these experiments we concluded that methyl nitrite is mutagenic. Possible mechanisms of action of methyl nitrite are discussed, and it is suggested that mutagenicity may be a general property of alkyl nitrites. 相似文献
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Doel JJ Godber BL Goult TA Eisenthal R Harrison R 《Biochemical and biophysical research communications》2000,270(3):880-885
Xanthine oxidase (XO) was shown to catalyze the reduction of isoamyl and isobutyl nitrites to nitric oxide (NO) in the presence of xanthine under anaerobic conditions. NO was produced at a stoichiometric ratio of 2:1 versus urate generation, steady-state analysis of which showed Michaelis-Menten kinetics with xanthine as varied substrate and substrate inhibition with varied organic nitrite. Under the conditions of NO generation from isoamyl nitrite, XO was progressively inactivated by a mechanism involving conversion of Mo=S to Mo=O, yielding "desulfo" enzyme. It is proposed that XO is involved in the metabolism of organic nitrites to NO in vivo and that the observed inactivation serves to explain the phenomenon of tolerance. 相似文献
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G. R. Kalamkarov T. S. Konstantinova A. E. Bugrova T. F. Shevchenko I. V. Tsapenko M. V. Zueva A. N. Ivanov 《Biophysics》2010,55(4):610-614
The possibility and the mechanism of the reduction of nitrites in retinal vessels under acute hypoxia in vivo have been investigated.
An experimental model of rat retinal ischemia was elaborated using laser coagulation of retinal vessels. It was demonstrated
that vessel thrombosis does not occur if the nitrite concentration in the vessels is increased. It was proposed that, under
acute hypoxia, nitrites are reduced to NO, which results in drastic vasodilatation. Considering that the effect takes less
than a minute, this reduction cannot be due to hypoxic acidosis but is more likely associated with NO reduction by heme proteins.
It was found that increased concentration of nitrites protects the retina from the development of ischemia progress and that
preliminary administration of nitrites prevents apoptosis in the retina and a decrease in its photoelectric activity. 相似文献
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S. I. Dolomatov P. V. Shekk W. Zukow M. I. Kryukova 《Reviews in Fish Biology and Fisheries》2011,21(4):733-737
Presence in water is easily metabolized nitrogen-containing substances is a vital condition for the existence of food organisms
in ponds used for fish reproduction. At the same time, the end products of nitrogen metabolism—ammonia, nitrites and nitrates
are always displayed the body of fish into the environment, adding to the total number of these compounds dissolved in water.
Ammonia, nitrite and nitrate anions are formed during biological processes, as well as man-made origin, have toxic properties
and are considered as environmental factors that may limit fish productivity of reservoirs. The results of a brief review
of the literature showed that the features of nitrogen metabolism in fish are actual direction of research, both theoretical
science and in practical fish farming. Published the results of studies of amino acid metabolism in fish suggest that, firstly,
the processes responsible for the neutralization and the release of ammonia from the body of fish, as well as ontogenetic
aspects of the dynamics of formation and emission of ammonia is not fully understood. Meanwhile, several authors stressed
the importance of this area of interest for the formation of science-based ways to improve the efficiency of plant breeding
in fish culture. Secondly, endogenous nitrite, being the product of oxidation of the molecule nitric oxide and its transport
form, the norm are always present in fish. However, the mechanisms responsible for maintaining the stability of the concentration
of nitrite in the internal environment of fish, not well understood. Also, in our opinion, of interest to determine the physiological
rules of nitrites and nitrates in the body of various species, depending on the seasons and stages of ontogeny. Thirdly, the
literature pays much attention to the toxic properties of nitrite in water biocenosis. Certainly, the analysis of the manifestation
in fish tissue-specific toxic effects of nitrites and their derivatives—an important area of research. Nevertheless, we can
not exclude that it may be quite promising analysis of the incorporation of exogenous nitrite as a substrate exist in fish
of the physiological mechanisms re-synthesis of nitric oxide. This kind of “interference” of endogenous and exogenous nitrite-anions
are not causing serious structural damage to organs and tissues, however, can cause substantial damage to the practical fish
farming, causing changes in the level of regulatory mechanisms of fish at the most critical stages: when working with manufacturers,
the incubation of eggs, and larvae rearing and wintering fish. 相似文献
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The mechanism by which nitrite inhibits outgrowing spores of Bacillus cereus T was examined by using techniques developed earlier for nitrite analogs. The morphological stage of inhibition, cooperativity effects, effect of pH on inhibition, kinetics of protection against iodoacetate incorporation into membrane sulfhydryl groups, and protection against the bacteriocidal effect of carboxymethylation by iodoacetate indicate that nitrite acts as a membrane-directed sulfhydryl agent. The mechanism by which nitrite modifies the chemical reactivity of the sulfhydryl group could be either direct covalent modification or inactivation through communication with another modified membrane component. Profiles of pH effects suggest that the active agent is the protonated form of nitrite. The nitrite concentrations which modify membrane sulfhydryl activity coincide with those which have a bacteriostatic effect. These results are consistent with membrane sulfhydryl modification as a component of the mechanism of nitrite-induced bacteriostasis in this aerobic sporeformer. 相似文献
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The mechanism by which nitrite inhibits outgrowing spores of Bacillus cereus T was examined by using techniques developed earlier for nitrite analogs. The morphological stage of inhibition, cooperativity effects, effect of pH on inhibition, kinetics of protection against iodoacetate incorporation into membrane sulfhydryl groups, and protection against the bacteriocidal effect of carboxymethylation by iodoacetate indicate that nitrite acts as a membrane-directed sulfhydryl agent. The mechanism by which nitrite modifies the chemical reactivity of the sulfhydryl group could be either direct covalent modification or inactivation through communication with another modified membrane component. Profiles of pH effects suggest that the active agent is the protonated form of nitrite. The nitrite concentrations which modify membrane sulfhydryl activity coincide with those which have a bacteriostatic effect. These results are consistent with membrane sulfhydryl modification as a component of the mechanism of nitrite-induced bacteriostasis in this aerobic sporeformer. 相似文献
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Although both organic and inorganic nitrates/nitrites mediate their principal effects via nitric oxide, there are many important differences. Inorganic nitrate and nitrite have simple ionic structures and are produced endogenously and are present in the diet, whereas their organic counterparts are far more complex, and, with the exception of ethyl nitrite, are all medicinally synthesised products. These chemical differences underlie the differences in pharmacokinetic properties allowing for different modalities of administration, particularly of organic nitrates, due to the differences in their bioavailability and metabolic profiles. Whilst the enterosalivary circulation is a key pathway for orally ingested inorganic nitrate, preventing an abrupt effect or toxic levels of nitrite and prolonging the effects, this is not used by organic nitrates. The pharmacodynamic differences are even greater; while organic nitrates have potent acute effects causing vasodilation, inorganic nitrite's effects are more subtle and dependent on certain conditions. However, in chronic use, organic nitrates are considerably limited by the development of tolerance and endothelial dysfunction, whereas inorganic nitrate/nitrite may compensate for diminished endothelial function, and tolerance has not been reported. Also, while inorganic nitrate/nitrite has important cytoprotective effects against ischaemia-reperfusion injury, continuous use of organic nitrates may increase injury. While there are concerns that inorganic nitrate/nitrite may induce carcinogenesis, direct evidence of this in humans is lacking. While organic nitrates may continue to dominate the therapeutic arena, this may well change with the increasing recognition of their limitations, and ongoing discovery of beneficial effects and specific advantages of inorganic nitrate/nitrite. 相似文献
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Curvacin A is a listericidal bacteriocin produced by Lactobacillus curvatus LTH 1174, a strain isolated from fermented sausage. The response of this strain to an added curing agent (sodium nitrite) in terms of cell growth and bacteriocin production was investigated in vitro by laboratory fermentations with modified MRS broth. The strain was highly sensitive to nitrite; even a concentration of 10 ppm of curing agent inhibited its growth and both volumetric and specific bacteriocin production. A meat simulation medium containing 5 ppm of sodium nitrite was tested to investigate the influence of the gas phase on the growth and bacteriocin production of L. curvatus LTH 1174. Aerating the culture during growth had no effect on biomass formation, but the oxidative stress caused a higher level of specific bacteriocin production and led to a metabolic shift toward acetic acid production. Anaerobic conditions, on the other hand, led to an increased biomass concentration and less growth inhibition. Also, higher maximum volumetric bacteriocin activities and a higher level of specific bacteriocin production were obtained in the presence of sodium nitrite than in fermentations under aerobic conditions or standard conditions of air supply. These results indicate that the inhibitory effect of the curing agent is at least partially masked under anaerobic conditions. 相似文献