摘要:

AbstractPreparative techniques were developed for the purpose of visualizing, by negative contrast, some of the cytological characteristics of unsectioned cells ofPseudomonas aeruginosa.Concentrated fimbriae free from cells had a length of approximately 1.5 μm and a diameter of 6 nm. Pyocin‐like structures ranging in length from 32‐64 nm with a width of 8.6 nm were “attached” to the terminal ends of a small percentage of these fimbriae. Microtubules and ringlets having a diameter of 10‐20 nm were also visualized in the bacteria. Budding or evagination of cell wall material in multiple units up to 135 nm in length was frequently observed in older cultures grown on

ISSN:0044-2208    

DOI:10.1002/jobm.19740140402

出版商:Akademie‐Verlag    

年代:1974

数据来源: WILEY

摘要:

AbstractThe dap‐dependent mutant ofEscherichia colicould grow in the presence of several analogues of diaminopimelic acid (dap). The multiplication proceeded without any apparent difference for several hours when dap was replaced with 2,6‐diamino‐4‐fluoro‐pimelic acid or lanthionine. Only growth without accompanying division could be detected in the presence of 2,6‐diamino‐4‐hydroxypimelic acid (hydroxy‐dap).3H‐hydroxy‐dap was incorporated into the TCA precipitable material under these conditions. 2,4,6‐triaminopimelic acid, probably also 2,6‐diamino‐5‐oxo‐pimelic acid could not substitute dap in the synthesis of murein. The synthesis of DNA measured by the incorporation of3H‐thymidine was not inhibited by hydroxy‐dap but the formation of the cross wall was impaired. The rods were longer, formed bulges in the central part of the cell and ultimately lyzed. Selenium‐lanththionine was more toxic but even in its presence some growth occurred and DNA synthesis took place. The replacement of dap with hydroxy‐dap stimulated the degradation of

ISSN:0044-2208    

DOI:10.1002/jobm.19740140403

出版商:Akademie‐Verlag    

年代:1974

数据来源: WILEY

摘要:

AbstractNostoc muscorumcould grow heterotrophically and successfully utilized a number of different sugars. Glucose proved to be the best sugar tested for growth and nitrogen fixation. However, citrate was outstanding among the different organic acids tried in allowing a substantial algal growth and consequently a high amounts of fixed nitrogen. The chemical analysis of the algal cells as well as the culture filtrate revealed the presence of various amino acids as well as auxine like substances.

ISSN:0044-2208    

DOI:10.1002/jobm.19740140404

出版商:Akademie‐Verlag    

年代:1974

数据来源: WILEY

摘要:

AbstractFirst, the kinetics and frequency of sporulation of twoBacillus megateriumstrains were determined after transition to nitrogen starvation. As the formation of the spore septum started at 1 hour after the shift, the initiation of sporogenesis was similar to that observed earlier in carbohydrate limited cultures. But later processes of sporulation were retarded and partly inhibited.From these strains two sporulation defective mutants were isolated. In ammonia‐, resp. glucose‐ or arabinose‐limited cultures cell division of the sporogenic and asporogenic strains was studied electronmicroscopically. Samples were taken from 2 generations before the transition to the stationary growth phase (t0) through 3 hours after the shift.Three types of division behaviour were observed during the transition to nitrogen‐(N) or carbon‐(C)‐starvation:1The initiation of division was inhibited already 1 ‐ 2 generations before cessation of net growth. In average, about 70% of all visibly initiated division septa were completed byt0or shortly after that time. This type was expressed in all sp+‐cultures and in the N‐limited sp−‐populations.2Initiation of septum formation was stimulated 1 ‐ 2 generations beforet0in sp−‐strains under C‐limitation. About 80% of all initiated septa were completed, if citrate was absent.3The completion of the division septum was completely blocked independent of whether initiation was stimulated or inhibited. This inhibition of late division processes occurred with sp−‐strains under C‐ or N‐limitation in glucose‐citrate medium.From these results it is concluded that the metabolism of sp+‐ and sp−‐strains differs already 1 ‐ 2 generations beforet0. Concerning factors controlling division early sporulating cells resemble N‐starved cells, independent of the composition of the medium. Initiation of division is at least influenced by the ratio of catabolic to anabolic reactions in a cell. Initiation and completion of the septum are separately controlled steps of the division proces

ISSN:0044-2208    

DOI:10.1002/jobm.19740140405

出版商:Akademie‐Verlag    

年代:1974

数据来源: WILEY

摘要:

AbstractCarboxin (= vitavax = DCMO) is rapidly oxidized by hydrogen peroxide or H2O2generating systems as riboflavin, flavin enzymes with or without substrate, to the more water soluble nontoxic sulfoxid (DCMOS). Illumination enhances the inactivation. Peroxidase is without effect. Isolated mitochondria from sensitive as well as from insensitive fungal species have the ability to oxidize DCMO, which leads to a leakage of the compounds mainly in form of DCMOS from the mitochondria. Among several fungal species investigated onlyUstilago maydis in vivooxidizes DCMO to a higher degree. The further oxidation of DCMOS to the corresponding dioxid (DCMOD = plantvax) occurs only under certain conditions to a limited extent. Proteases are unable to attack the ‐ CONH‐bounding. It is assumed thatin vivomainly flavin enzymes are responsible for the rapid oxidative inactivation of DCMO (vitav

ISSN:0044-2208    

DOI:10.1002/jobm.19740140406

出版商:Akademie‐Verlag    

年代:1974

数据来源: WILEY

摘要:

AbstractDistamycin A and netropsin are basic oligopeptide antibiotics. Though the chemical structure of both antibiotics is very similar, the action on grampositive and gramnegative bacteria is quite different. Distamycin A acts only on grampositive bacteria, while netropsin inhibits grampositive as well as gramnegative bacteria.Our experiments with the normal rod form and the stable protoplast type L‐form ofE. coliW1655F+have shown that distamycin A inhibits gramnegative bacteria to the same extent as netropsin, when wall‐less L‐form‐ells were used. The normal rod cells were inhibited by netropsin only. That means that the wall prevents the penetration of distamycin A as reported earlier for the macrolid antibiotics, actinomycin C and kir

ISSN:0044-2208    

DOI:10.1002/jobm.19740140407

出版商:Akademie‐Verlag    

年代:1974

数据来源: WILEY

ISSN:0044-2208    

DOI:10.1002/jobm.19740140408

出版商:Akademie‐Verlag    

年代:1974

数据来源: WILEY

ISSN:0044-2208    

DOI:10.1002/jobm.19740140409

出版商:Akademie‐Verlag    

年代:1974

数据来源: WILEY

ISSN:0044-2208    

DOI:10.1002/jobm.19740140410

出版商:Akademie‐Verlag    

年代:1974

数据来源: WILEY

ISSN:0044-2208    

DOI:10.1002/jobm.19740140412

出版商:Akademie‐Verlag    

年代:1974

数据来源: WILEY