摘要:

AbstractFermentation balance studies were carried out onClostridium tertiumgrown with and without nitrate in the medium. Nitrate reduction increased the efficiency of energy produced from glucose by permitting the utilization of additional sites of substrate level phosphorylation. The effect was even more dramatic inC. tertiumthan inC. perfringens, with increased cell yields of about 30% being observed in the former compared with 20% in the latterUnlikeC. perfringens, C. tertiumresponded to the presence of nitrate in the medium with an increased growth rate. A slight increase in theYATPof these cultures was also observed, and quantitatively, this appeared to be consistent with the prediction of STOUTHAMMER and BETTENHAUSSEN thatYATPwill vary with the growth rateThus,C. tertium, likeC. perfringens, was able to use nitrate as an electron acceptor in conjunction with its energy metabolism, suggesting that this trait may be widespread among the nitrate‐reducing anaerobe

ISSN:0044-2208    

DOI:10.1002/jobm.19770170702

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractStreptomyces roseochromogenes(NRRL B‐1233) converted estrone predominantly into its 16α‐hydroxyl derivative. Chemical and spectroscopic (UV, IR, NMR, MS) methods were used in establishing the structure and stereochemistry of the oxidation product. The product was assigned as 16α‐hydroxyestrone (yield, 17%). No other oxidation product was detected in this experiment. An interrelationship between cell growth and 16α‐hydroxy‐estrone formation was observed. Also, 16α‐hydroxylation of estrone was observed in resting cells16α‐Hydroxylase showed good activity at 3.7 × 10−4M of estrone concentration and was completely inhibited by 1.1 × 10−3M. These results indicate the presence of a constitutive 16α‐hydroxylase i

ISSN:0044-2208    

DOI:10.1002/jobm.19770170703

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe blue‐green algaNostoc linckiawas treated with nitrosoguanidine and two classes of morphological mutant clones were isolated. One class shows certain abnormal phenotypic features of vegetative cells, spores, and heterocysts. It has increased heterocyst frequency and impaired growth rate. The other class exhibits an altered heterocyst spacing pattern. Both classes of mutants have reduced nitrogenase activit

ISSN:0044-2208    

DOI:10.1002/jobm.19770170704

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractCell free extracts were prepared fromE. coliCRT266 9 min after infection with T3 phages. RNA synthesis in these extracts is almost entirely due to T3 RNA polymerase. The inactivation of T3 RNA polymerase in these extracts proceeds rapidly at 42 °C. 90% of the activity is lost within 10 min at this temperature. Under conditions where the formation of a stable initiation complex with T3 DNA is possible,i.e., in the presence of GTP, ATP, and UTP the T3 RNA polymerase becomes protected against heat inactivation losing only 10% of its activity during an exposure to 42 °C for 10 min. Studies on the time course of RNA synthesis have shown that reinitiation is still possible at 37 °C and 42 °C. At 44 °C, however, RNA synthesis stops abruptedly after 3 min indicating that reinitiation does no longer take place. The elongation of already initiated T3 RNA chains is rather resistant to heat. At 44 °C the same elongation rates are observed as at 37 °C and 42 °C, respe

ISSN:0044-2208    

DOI:10.1002/jobm.19770170705

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractA mathematical model of microbial growth is presented and examined which, in contrast to the well‐known MONOD model, includes transitions from one cell „bottle‐neck”︁ to another. This is achieved by introducing an intermediate product in the model. Three variants of the model for different regulatory functions of the intermediate are considered. The results permit to describe a set of experimentally observable microbial growth curves. According to the model, the shape of the growth curves, the kinetics of substrate consumption and changes of intermediate concentration depend on culture prehistory and the nature of the intermediate regulatory

ISSN:0044-2208    

DOI:10.1002/jobm.19770170706

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractDistribution of radioactivity in paromomycin ascertained after application of14C‐D‐glucose,14C‐D‐glucosamine,14C‐2‐deoxystreptamine, respectively,14C‐D‐ribose is taken as basis for a biosynthesis scheme: While ribose bound in the antibiotic originates from glucose by oxidation and following decarboxylation, glucosamine is formed via fructose‐6‐phosphate. Paromose I arises from glucosamine, but not the cyclohexan derivative 2‐deoxystreptamine, whose biosynthesis pathway is directly

ISSN:0044-2208    

DOI:10.1002/jobm.19770170707

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractDie temperatursensitive filamentöse Mutantets33‐6 vonB. subtilisSB 19 zeichnet sich durch unterschiedliches Teilungsvermögen bei restriktiver und permissiver Temperatur aus (30 °C Kurzstäbchen, 46 °C Filamente). Sie verfügt unter restriktiven Verhältnissen (46 °C) über einen funktionsfähigen Replikationsmechanismus. Die während der Sporenkeimung bei 45 °C begonnene DNS‐Replikation kann auch unter restriktiven Temperaturbedingungen beendet werdenKurzzeitige Beeinflussung gekeimter Sporen durch Inkubation bei 48 °C und anschließender shift down zu 46 °C verändern den DNS‐Syntheseablauf, verhindern jedoch die Filamentbildung nichtTeilungsinduktion durch Temperaturwechsel von 46 °C zu 30 °C ist mit gesteigerter DNS‐Synthese gekoppelt. Gegenüber einer bei 46 °C verbleibenden Kontrolle verstärkt sich die DNS‐SyntheseaktivitätDie DNS‐Synthese nach Temperaturerniedrigung läuft unabhängig von der Proteinsynthesehemmung durch Chloramphenicol ab. Auch bei blockierter RNS‐Synthese in aminosäurefreiem Medium ist die DNS‐Replikation möglich. Lediglich Mitomycin C in geeigneten Konzentrationen hemmt bzw. beein

ISSN:0044-2208    

DOI:10.1002/jobm.19770170708

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe incorporation of exogenous thymidine and thymine into acid‐insoluble material ofThermoactinomyces vulgarishas been studied during germination and subsequent growthThymine is not incorporated. The incorporation of thymidine stops after a short time due to the rapid breakdown of thymidine to thymine and deoxyribose‐1‐phosphate by the inducible thymidine phosphorylaseDeoxyadenosine enhances the incorporation of thymidine as well as of thymine and prolongs the time of uptake. Uridine stimulates only the incorporation of thymidine but not of thymine. These effects can be explained by the function of these substances within the salvage pathway. Deoxyadenosine acts as donor of deoxyribosyl groups being necessary for the conversion of thymine to thymidine by thymidine phosphorylase and uridine inhibits thymidine phosphorylase, and thereby it prevents the degradation of thymidine to thymineThymidine is incorporated into alkali‐, RNase‐ and protease‐stable, hot TCA‐soluble and DNasesensitive material. That means that the cellular DNA ofT. vulgariscan be specifically labelled by radioactive thymidine in the presence of deoxyadenosine and uridine,

ISSN:0044-2208    

DOI:10.1002/jobm.19770170709

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

ISSN:0044-2208    

DOI:10.1002/jobm.19770170710

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

ISSN:0044-2208    

DOI:10.1002/jobm.19770170713

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY