首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
By comparing three methods for disruption of normal bacteria and bacterial L-forms (process ing in the Ribi-Sorvall Cell Fractionator or in the X-press of Edebo, and osmotic shock), it was shown that the outcome of fractionation experiments with disintegrated bacteria is highly influenced by the disintegration method employed. The localization of seven enzymes in normal Proteus bacteria and Proteus L-forms was studied. The experimental results indicate that the succinic dehydrogenase and NADH oxidase are located in the membranous part of both types of organisms, the glucose-6-phosphate and isocitric dehydrogenase, the fumarase, the catalase, and the acid phosphatase in the “soluble” protoplasm.  相似文献   

2.
Structure of bacterial L forms and their parent bacteria   总被引:2,自引:2,他引:2  
Weibull, Claes (Rocky Mountain Laboratory, Hamilton, Mont.). Structure of bacterial L forms and their parent bacteria. J. Bacteriol. 90:1467-1480. 1965.-Light and electron microscopic studies were done on normal cells and L forms of Proteus mirabilis, Staphylococcus aureus, and Corynebacterium sp. grown in liquid media. Under the prevailing growth conditions, the L forms studied were morphologically indistinguishable from one another. They appeared as approximately spherical elements occurring singly or more often connected with each other by thinner portions of cell material. In sections of large L forms, the following structures were seen: a peripheral, triple-layered ("unit") membrane, a granular cytoplasm, nuclear regions, and vacuoles limited by membranes. Small bodies often were present inside the vacuoles. These bodies also contained a peripheral membrane and a granular cytoplasm but usually no nuclear regions. The normal bacteria from which the L forms were derived differed markedly in structure from one another, especially in the surface layers of the cells.  相似文献   

3.
4.
5.
6.
Эксперименты прово дились, чтобы побуди ть L-цикл и добиться ст абилизации L-форм в ба ктерии, происходящи х в nasopharynx белых крыс, путем иммунизации животны х с вакциной и гамма-г лобулин готовится и з этих бактерий. Резу льтаты распределил ись следующим образ ом.
  1. (1)
    обследование бакт ериальных biocenose от nasopharynx бел ых крыс (Dobr Вода порода), осуществляется на р азличных сезонов, по казал, что () itStreptococcus viridans присут ствовал на регулярн ой основе и что Gramnegative parvobacteria в том числе-как Pasteurella haemophilic и ба ктерии, от бактерий (itColi-Aerogenes группы и) () itNeisseriae произо шло очень часто.  相似文献   

7.
New data are presented on the ability of different aerobic spore-forming bacteria isolated from the organism of urological patients to produce L-forms of these microorganisms in the presence of penicillin and ampicillin. Bacillus cereus is shown to be the most resistant to these antibiotics.  相似文献   

8.
Some biological properties of S. flexneri have been studied. The strains of this bacterial species have been shown to produce DNAase in 98.8 +/- 0.77% of cases and RNAase in 97.4 +/- 1.5% of cases. The capacity for the positive reaction with Congo red as early as after 24-hour incubation in the thermostat has proved to be characteristic of S. flexneri (91.1 +/- 3.6%). If stored at 4 degrees C in semiliquid agar, S. flexneri cultures have been found to retain their capacity for producing the above-mentioned enzymes as long as 10-13 years. All S. flexneri serovars under study, with the exception of serovar 6, have shown high activity in the manifestation of their properties.  相似文献   

9.
10.
Lactic-acid bacteria (L. fermenti, L. acidophilus, L. delbruecki), when developing resistance to antibiotics, did not change their main biochemical, antagonistic properties and did not lose capacity for acid production. Only a decrease in their growth rate and a change in their sensitivity to the action of ultraviolet radiation were observed. Both initial and antibiotic-resistant strains were capable of taking on the mucous membrane of the large and small intestines in CBA mice.  相似文献   

11.
The pathogenicity of B. abortus 870 L-forms obtained by long-term passaging of virulent culture on media with penicillin and of revertants obtained in vitro and in vivo was studied. L-form cultures stimulated only a mild response of the reticulo-endothelial system of the animal organism, at the same time displaying a certain level of toxicity. In vitro revertants approximated to L-forms, while in vivo revertants stood closer to the initial virulent culture, as regards pathogenicity. This seems to be evidence of a potential danger of brucella L-forms for the human and animal organisms.  相似文献   

12.
The authors present the data concerning the study of 200 patients suffering from chronic pyelonephritis; in 28 of these L-forms of bacteria were revealed in the urine. Of 46 L-cultures isolated from these patients 13 reversed into bacterial forms, 8 failed to reverse and were referred to the stable L-forms; the rest 25 L-cultures perished during the 8th--10th passage. This led to a supposition that the relapses and exacerbations of the infectious process in pyelonephritis were associated with the change of the L-forms into bacterial ones, and that the persistence of the L-forms in the kidney tissue promoted the maintenance of the chronic process.  相似文献   

13.
14.
高效厌氧纤维素降解细菌的分离及酶特性研究   总被引:3,自引:0,他引:3  
采用透明圈初筛和滤纸降解率复筛的方法从内蒙古绵羊瘤胃内容物中分离到高效厌氧纤维素降解细菌4株.通过形态学、生理生化反应、生态特性和遗传型的鉴定,所分离的4株菌WHQ、LYQ、LBG-1和NDF-3分别归为溶纤维丁酸弧菌(Butyrivibrio fibrisollvens)、黄色瘤胃球菌(Ruminococcus flavefaciens)、产琥珀酸丝状杆菌(Fibrobacter succinogenes)和解多糖梭菌(Clostridium polysaccharolyticum).测定了4株菌对滤纸的降解率,WHQ、LYQ、LBG-1和NDF-3的2周滤纸降解率分别为25.1%、14.3%、21.0%和20.6%.本研究同时对4株菌的滤纸酶活力、羧甲基纤维素酶活力和β-葡萄糖苷酶活力进行了测定.  相似文献   

15.
The review is devoted to literature data on antimicrobial metabolites produced by lactic acid bacteria (LAB), which have long been used for the preparation of cultured dairy products. This paper summarizes data on low-molecular-weight antimicrobial substances, which are primary products or by-products of lactic fermentation. Individual sections are devoted to a variety of antifungal agents and bacteriocins produced by LAB; their potential use as food preservatives has been discussed. The characteristics and classification of bacteriocins are presented in a greater detail; their synthesis and mechanism of action are described using the example of nisin A, which belongs to class I lantibiotics synthesized by the bacterium Lactococcus lactis subsp. lactis. The mechanism of action of class II bacteriocins has been demonstrated with lacticin. Prospective directions for using LAB antimicrobial metabolites in industry and medicine are discussed in the Conclusion.  相似文献   

16.
L-forms of Clostridium perfringens were induced in brain heart infusion broth containing 10% sucrose and 2 units of penicillin. After a few hours of growth, spheroplasts, granules, and elongated bacilli were apparent. At 24-h intervals, serial subcultures were made in the above medium which resulted in a culture composed entirely of spheroplasts (or protoplasts) and granules. Upon the withdrawal of penicillin these L-form cultures grew well and, after 100 passages, there was no reversion to the bacillary form. Sucrose could also be withdrawn from the medium. The effects of centrifugation, osmotic stabilizer, ultraviolet light, temperature, pH, and lyophilization upon stable L-forms were examined. L-forms were found to attach to the walls of culture tubes during trowth and sheets of L-form growth were obtained on cover slips in Leighton tubes and on the sides of medicine bottles.  相似文献   

17.
18.
Structural data as collated in the Protein Data Bank (PDB) have been widely applied in the study and prediction of protein-protein interactions. However, since the basic PDB Entries contain only the contents of the asymmetric unit rather than the biological unit, some key interactions may be missed by analysing only the PDB Entry. A total of 69,054 SCOP (Structural Classification of Proteins) domains were examined systematically to identify the number of additional novel interacting domain pairs and interfaces found by considering the biological unit as stored in the PQS (Protein Quaternary Structure) database. The PQS data adds 25,965 interacting domain pairs to those seen in the PDB Entries to give a total of 61,783 redundant interacting domain pairs. Redundancy filtering at the level of the SCOP family shows PQS to increase the number of novel interacting domain-family pairs by 302 (13.3%) from 2277, but only 16/302 (1.4%) of the interacting domain pairs have the two domains in different SCOP families. This suggests the biological units add little to the elucidation of novel biological interaction networks. However, when the orientation of the domain pairs is considered, the PQS data increases the number of novel domain-domain interfaces observed by 1455 (34.5%) to give 5677 non-redundant domain-domain interfaces. In all, 162/1455 novel domain-domain interfaces are between domains from different families, an increase of 8.9% over the PDB Entries. Overall, the PQS biological units provide a rich source of novel domain-domain interfaces that are not seen in the studied PDB Entries, and so PQS domain-domain interaction data should be exploited wherever possible in the analysis and prediction of protein-protein interactions.  相似文献   

19.
The effect of compound structure on the microbial transformation of a series of substituted anilines was investigated. For the pure-culture and environmental water samples studied, the rate of transformation of the compounds decreased in the following order: aniline greater than 3-bromoaniline greater than 3-chloroaniline greater than 3-methylaniline greater than 3-methoxyaniline greater than 3-nitroaniline greater than 3-cyanoaniline. Second-order rate constants (kb) for each compound was calculated by using bacterial and compound concentrations measured as a function of time. The rate constants correlated with steric parameters. Water samples also were used in kinetic studies with three of the compounds (aniline, 3-chloroaniline, and 3-nitroaniline) to test the relationships with mixed bacterial populations. A simple linear regression of van der Waals radius of the substituent group with log kb gave correlation coefficients (r2) of 0.924 for the river isolate and 0.99 for the mixed populations. Analyses of pure-culture and mixed-population samples by thin-layer chromatography indicate that the primary products are catechols. This finding suggests that the transformation pathway involves oxidative deamination of the anilines.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号