Nutritional requirements for chloramphenicol biosynthesis in Streptomyces venezuelae

1983 ◽  
Vol 29 (2) ◽  
pp. 247-253 ◽  
Author(s):  
S. Chatterjee ◽  
L. C. Vining ◽  
D. W. S. Westlake

Cultures grown in a glycerol serine lactate medium were used to establish the inoculation procedure, aeration level, and trace-mineral nutrition optimizing chloramphenicol production in Streptomyces venezuelae. The stimulatory effect of lactate in this medium was concluded not to be an artifact of medium preparation but to reside in its influence on carbon-source utilization. In media with ammonium sulfate as a nonrestricting source of nitrogen, chloramphenicol production varied with the carbon source chosen. Production occurred during the growth phase and was highest on galactose, lactose, cellobiose, and starch. The rate of synthesis was related directed to the growth rate and decreased in the stationary phase. Variation of the nitrogen source with glucose as a nonrestricting source of carbon showed that the highest antibiotic titres were obtained with poorly utilized compounds such as isoleucine or phenylalanine. Proline gave yields comparable with those obtained in the more complex glycerol serine lactate medium in a shorter time. Although rate of growth is not the sole determining parameter, chloramphenicol synthesis is concluded to be a "growth-linked" process.

1974 ◽  
Vol 20 (2) ◽  
pp. 263-265 ◽  
Author(s):  
Edward E. Ishiguro

A chemically defined medium for host-independent (H-I) derivatives of Bdellovibrio bacteriovorus strain 109 Davis has been developed. Carbon-source utilization studies indicated that H-I cells can assimilate a wider variety of compounds than host-dependent bdellovibrios. The defined medium did not support growth of freshly isolated H-I strains which required unidentified growth factors present in Escherichia coli cell-free extracts and in yeast extract.


Polar Science ◽  
2021 ◽  
pp. 100738
Author(s):  
Yuki Hatano ◽  
Takumi Yoshida ◽  
Seri Matsuzuka ◽  
Takashi Osono ◽  
Satoru Hobara ◽  
...  

2020 ◽  
Vol 11 ◽  
Author(s):  
Stefanie Wijnants ◽  
Michael Riedelberger ◽  
Philipp Penninger ◽  
Karl Kuchler ◽  
Patrick Van Dijck

2016 ◽  
Vol 9 (1) ◽  
pp. 62-67 ◽  
Author(s):  
R. Jame ◽  
V. Zelená ◽  
B. Lakatoš ◽  
Ľ. Varečka

Abstract Five bacterial isolates were tested for their ability to generate hydrogen during anaerobic fermentation with various carbon sources. One isolate from sheep rumen was identified as Escherichia coli and four isolates belonged to Clostridium spp. Glucose, arabinose, ribose, xylose, lactose and cellobiose were used as carbon sources. Results showed that all bacterial strains could utilize these compounds, although the utilization of pentoses diminished growth yield. The excretion of monocarboxylic acids (acetate, propionate, formiate, butyrate) into medium was changed after replacing glucose by other carbon sources. Di- and tricarboxylic acids were excreted in negligible amounts only. Spectra of excreted carboxylic acids were unique for each strain and all carbon sources. All isolates produced H2 between 4—9 mmol·L−1 during the stationary phase of growth with glucose as energy source. This value was dramatically reduced when pentoses were used as carbon source. Lactose and cellobiose, starch and cellulose were suitable substrates for the H2 production in some but not all isolates. No H2 was produced by proteinaceous substrate, such as blood. Results show that both substrate utilization and physiological responses (growth, excretion of carboxylates, H2 production) are unique functions of each isolate.


Microbiology ◽  
2005 ◽  
Vol 151 (5) ◽  
pp. 1403-1408 ◽  
Author(s):  
Daan van den Broek ◽  
Thomas F. C. Chin-A-Woeng ◽  
Guido V. Bloemberg ◽  
Ben J. J. Lugtenberg

Pseudomonas sp. strain PCL1171 undergoes reversible colony phase variation between opaque phase I and translucent phase II colonies, which is dependent on spontaneous mutations in the regulatory genes gacA and gacS. Mutation of the mutS gene and constitutive expression of rpoS increases the frequency at which gac mutants appear 1000- and 10-fold, respectively. Experiments were designed to study the relationship between gacS, rpoS and mutS. These studies showed that (i) a functional gac system is required for the expression of rpoS, (ii) RpoS suppresses the expression of mutS and therefore increases the frequency of gac mutants, and (iii) upon mutation of rpoS and gacS, the expression of mutS is increased. Mutation of gacS abolishes suppression of mutS expression in stationary growth, suggesting that additional gac-dependent factors are involved in this suppression. In conclusion, inefficient mutation repair via MutS, of which the expression is influenced by gacA/S itself and by rpoS in combination with other factors, contributes to the high frequency of mutations accumulating in gacA/S. The role of RpoS in the growth advantage of a gac mutant was analysed, and mutation of rpoS only reduced the length of the lag phase, but did not affect the growth rate, suggesting a role for both RpoS and a reduction of metabolic load in the growth advantage of a gac mutant.


Author(s):  
В.А. Четырбоцкий ◽  
А.Н. Четырбоцкий

Выполнена математическая формализация уравнений модели, для построения которой использовалась концепция системы ресурспотребитель. В рассматриваемом случае потребителем выступает биомасса растений, а ресурсомраспределенные в узкой прикорневой зоне растений основные элементы его минерального питания (азот, фосфор и калий). Динамические уравнения модели следуют основному положению химической кинетики, согласно которому результат взаимодействия динамических переменных в системах рассматриваемого профиля определяется их произведением. Выполнена оценка параметров и установлена адекватность модели выборочным распределениям. В качестве выборочных распределений используется массив экспериментальных данных роста яровой пшеницы (Красноуфимская-100) на торфяной низинной почве, предварительная почвенная обработка которой проведена с помощью азотных, фосфорных и калийных удобрений. Modern mathematical models for the simulation of dynamics in the fertilizer-soil-plant system, the components of which are agricultural plants, soil microorganisms and elements of their mineral nutrition, are considered. Based on the analysis of the adopted provisions, a model that takes into account the relationships and the specific nature of the joint changes in its components has been developed. The mathematical formalization of the model equations is carried out, for the construction of which the concept of the resourceconsumer system was used. In this case, the consumer is the biomass of plants, and the content of the main elements of its mineral nutrition distributed in the narrow basal zone of plants is a resource. The dynamic equations of the model follow the basic principle of chemical kinetics, according to which the result of the interaction between dynamic variables in the systems of the profile in question is determined by their product. The equations also contain the self-limitation factor, which sets the growth rate of the curve for the logistic equation and the specific rate of the model variables saturation effect. Thus, the specific rate of change in biomass is determined by its natural growth rate, the weighted sum of the nutrient contents in plants, and intraspecific competition. The rate of change in the content of these elements per unit of biomass is proportional to their current content in the rhizosphere and to the factor of the mutual influence of the elements on each other. The parameters are estimated and the adequacy of the model to sample distributions is established. An array of experimental data on the growth of spring wheat (Krasnoufimskaya-100) on peat lowland soil, the preliminary soil treatment of which was carried out using nitrogen, phosphorus, and potassium fertilizers, is used as sample distributions. The coefficients obtained as a result of parameter estimation and the calculated distributions of model dynamic variables with a sufficiently high degree of adequacy correspond to their experimental distributions and reflect the real situation of the system evolution.


2010 ◽  
Vol 56 (12) ◽  
pp. 979-986 ◽  
Author(s):  
E. Tang ◽  
C.B. Hill ◽  
G.L. Hartman

Fusarium virguliforme is the cause of sudden death syndrome in soybean. Physiological variability among isolates of the fungus is unknown. One way to measure physiologic variability is to analyze growth on different carbon sources. The carbon source utilization profiles of 18 F. virguliforme isolates were examined using the Biolog FF 96-well microplate, which contains 95 different carbon sources. The utilization of dextrin, d-mannitol, maltotriose, d-lactic acid methyl ester, N-acetyl-d-galactosamine, salicin, d-trehalose, and l-alanine differed significantly among isolates (P = 0.05). Carbon sources were grouped into 3 clusters based on their ability to promote growth of F. virguliforme, after calculating Euclidean distances among them. About 12% of the carbon sources promoted a high amount of mycelial growth, 39% promoted a medium amount of growth, and 49% promoted a low amount of mycelial growth; the latter was not significantly different from the water blank control. A hierarchical tree diagram was produced for the 18 isolates based on their carbon source utilization profiles using Ward’s hierarchical analysis method. Two main clusters of isolates were formed. One cluster represented greater average mycelial growth on all of the carbon sources than the other cluster. In this study, variability in carbon source utilization among F. virguliforme isolates was evident, but the results were not associated with geographic origin of the isolates, year collected, or published data on aggressiveness. Additional research is needed to determine if these carbon utilization profiles are associated with other biological characteristics, like spore germination, propagule formation, and saprophytic competitiveness.


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