摘要:

AbstractFive species of the genusMicrosporum (M. audouinii, M. canis, M. cookei, M. gypseum, M. vanbreuseghemii) were cultivated in an Oleum pedum tauri‐glutamate‐broth for three months. Amongst themM. gypseumproduced the highest,M. audoiniithe lowest amount of mycelium (dry weight) under these conditions. Both species differed further in rate and strength of growth, uptake of phosphate, deamination of glutamate, uptake of ammonium from, and excretion of enzymes into the medium.M. gypseumexceededM. audouiniionly with regard to the lipolytic, but not to the proteolytic or phospholytic activity. No direct correlations exist between growth rate, enzyme production, and pathogenicity of these fu

ISSN:0044-2208    

DOI:10.1002/jobm.19720120602

出版商:Akademie‐Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractTwo enzymes splitting inorganic pyrophosphate (I and II) have been investigated inCandida utilis. The results indicate that only enzyme I (no considerable thermoinactivation — 10 min, 71 °C‐, optimum near pH 2.5, enzyme strongly bound to the cell, high splitting ratesin vivo, derepression under phosphate starvation conditions) is also able to split orthophosphoric monoesters. Thus, the enzyme I is an unspecific acid orthophosphoric monoester phosphohydrolase (E. C. 3.1.3

ISSN:0044-2208    

DOI:10.1002/jobm.19720120603

出版商:Akademie‐Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractIn carbohydrate‐limited, sporulatingB. megateriumcultures reversion to growth was initiated by transfer into medium containing glucose and yeast‐extract. From cultures grown with different doubling times the iknetics of commitment to sporulation and loss of reversibility were studied both by phase‐contrast and electron microscopy. Commitment to refractility occurred about 20 min after formation of the spore septum and 140 min before spores became refractil. Not all of the cells which did not reach this stage of commitment until the time of transfer were able to revert. Reversibility was already lost during formation of the spore septum. Stage II‐cells which had formed the spore septum before transfer were committed to stage III despite the presence of nutrients, but their further development was blocked. Thus, like in other spore‐formers the condition for undisturbed spore development was the formation of the forespore under starvation. As only stage I‐cells were able to undergo reversion to growth, commitment to refractility did not correspond to loss of reversibility, as could be shown with other spore‐formers.Before in reverting cells the first division septum appeared (about one hr after transfer) the cells doubled in length. During that time in about 50% of the cells additional wall material was laid down at the younger poles. The first division septum was not formed in the middle of the cell, but the part with the older pole which would have built the spore was larger. In the presence of penicillin G the parts of the reverting cells were influenced differently. The part containing the younger pole got thicker, while the other showed the no

ISSN:0044-2208    

DOI:10.1002/jobm.19720120604

出版商:Akademie‐Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractFrom the group A streptococcal strain 56188, mutants were selected for resistance to lincomycin. Among these, two distinguishable classes occurred: whereas mutations assigned to thelinAlocus did not change the susceptibility to erythromycin and were transducible by phage A25, class B mutations conferred erythromycin cross‐resistance and failed to be transducible under the conditions employed. Corresponding findings have previously been made concerning the properties of mutants selected for resistance to erythromycin.By two‐point transduction crosses, theeryAandlinAloci were placed in the same linkage group, as defined by cotransfer with phage A25. A common feature of mutants carrying both aneryAand alinAmutation was the slower growth compared to that of the parental strains bearing either mutation alone. This interaction amongeryAandlinAmutations proved to be strongest in certain combinations which were phenotypically unrecognizable because the resultant strains failed to develop colonies under the conditions used. On the other hand, the mutations of the established double mutants did not interact with respect to their effect on the resistance characteristics of the strains, which were the simple addition of the effects of the single mutations. Both the linkage relationships and the phenotypic properties of theeryAandlinAmutations suggested that they might occur in genes coding for ribosomal proteins.Mutations carried out by the B classes of the erythromycin‐resistant and lincomycin‐resistant strains appeared to be located outside theeryAlinAlinkage group in region(s), the function of which is

ISSN:0044-2208    

DOI:10.1002/jobm.19720120605

出版商:Akademie‐Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractWildtypzellen vonProteus mirabilisnehmen normalerweise Thymin gar nicht und Thymidin nur während einer relativ kurzen Inkubationszeit aus dem Kulturmedium auf. Der Einbau radioaktiver Präkursoren zur Markierung der DNS von Wildtypzellen ist jedoch nach Zugabe von Desoxypurinnucleosiden über einen großen Bereich der exponentiellen Wachstumsphase möglich. Für die Inkorporation von Thymin und Thymidin erwies sich Desoxyadenosin in einer Konzentration von 500 μg/ml als optimal. Die Verwertung von exogenem Thymidin für die DNS‐Synthese war jedoch im Vergleich zu Thymin effektiver.Aus der Spezifität des Einbaus der Präkursoren in die DNS ergibt sich die Möglichkeit, sie nach Ablauf einer Vormarkierungsperiode zur Untersuchung der DNS‐Synthese‐Kinetik vonP. mirabilis‐Wildtyp einzusetzen.Die erhaltenen Ergebnisse zeigen, daß das Verhalten vonP. mirabilisin wesentlichen Punkten in Bezug auf den Einbau von Thymin und Thymidin mit den von anderen Autoren beiEscherichia coligewonnenen Resul

ISSN:0044-2208    

DOI:10.1002/jobm.19720120606

出版商:Akademie‐Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractCarbon films or thin sections of plastic materials were introduced into the electron beam of an electron microscope and the fraction of electrons scattered enough not to reach the fluorescent screen was estimated by means of the exposure meter of the microscope. The values obtained showed that a simple relationship existed between the fraction of electrons scattered and the thickness of the sections (films) as estimated with a microtome or otherwise. In this way, film thicknesses between about 5 and 130 nm can rapidly be estimated. However, when sectioned material is studied, areas free of embedded material must be present in the sections.

ISSN:0044-2208    

DOI:10.1002/jobm.19720120607

出版商:Akademie‐Verlag    

年代:1972

数据来源: WILEY

ISSN:0044-2208    

DOI:10.1002/jobm.19720120608

出版商:Akademie‐Verlag    

年代:1972

数据来源: WILEY

ISSN:0044-2208    

DOI:10.1002/jobm.19720120609

出版商:Akademie‐Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractDieSh. flexneri‐Serotypen (mit Ausnahme des Serotyps 6) bilden Lipopolysaccharide, deren S‐spezifischer Teil in allen Fällen die gleiche Grundstruktur… 6‐GlcNAc‐1,2‐Rha‐1,3‐Rha‐1… besitzt. Die Vielzahl der Serotypen ergibt sich aus dieser Grundstruktur dadurch, daß alle 3 Monosaccharide zusätzlich Glucose bzw. O‐Acetyl enthalten können. Aus der chemischen Struktur und aus genetischen Gründen folgen einige Verbote der Kombination bestimmter Antigene. Nicht alle diese Verbote werden eingehalten. Das beruht auf der Anwesenheit von Fehlstellen im Molekül, d. h., nur die Existenz dieser Fehlstellen ermöglicht gewisse in der Natur beobachtete Antigenkombinationen.Es wird gezeigt, daß sowohl in bezug auf den Biosyntheseweg als auch in bezug auf die chemische Struktur die Unterteilung derSh. flexneri‐Antigene in Typen‐ und Gruppen‐antigene in chemischer Sicht ohne jede Basis ist.Erklärt werden weiterhin die Antigenvariabilität der Shigellen, die Antigenveränderungen nach lysogener Konversion bzw. nach Konjugation mit anderenSh. flexneri‐ bzw.E. coli‐Stämmen, das Wesen der SR‐Mutation un

ISSN:0044-2208    

DOI:10.1002/jobm.19720120610

出版商:Akademie‐Verlag    

年代:1972

数据来源: WILEY

ISSN:0044-2208    

DOI:10.1002/jobm.19720120611

出版商:Akademie‐Verlag    

年代:1972

数据来源: WILEY