Suppression of nitrate utilization by ammonium and its relationship to chloramphenicol production in Streptomyces venezuelae

1984 ◽  
Vol 30 (6) ◽  
pp. 798-804 ◽  
Author(s):  
S. Shapiro ◽  
L. C. Vining
Keyword(s):  
Nitrate Reductase ◽  
Nitrogen Source ◽  
Specific Activity ◽  
Marked Change ◽  
Biomass Accumulation ◽  
Nitrogen Sources ◽  
Antibiotic Biosynthesis ◽  
Streptomyces Venezuelae ◽  
Ammonium Production ◽  
Fermentation Broths

Cultures of Streptomyces venezuelae grown in a medium containing glucose with mixtures of ammonium and nitrate as the nitrogen source produced chloramphenicol in a distinct idiophase that followed biomass accumulation. Analysis of fermentation broths showed that ammonium and nitrate were taken up consecutively by the organism. Measurements of nitrate reductase in the mycelium established that the enzyme was constitutive and that its specific activity did not increase during the period when ammonium was exhausted from the medium and nitrate was assimilated. The enzyme was neither repressed nor inhibited by ammonium. Production of chloramphenicol was also delayed until ammonium had been consumed and remained slow until subsequent depletion of nitrate. Arylamine synthetase, the initial enzyme in the pathway of antibiotic biosynthesis, showed no marked change in specific activity during utilization of the two nitrogen sources. The result suggests that the mechanism causing preferential utilization of ammonium does not simultaneously control the onset of chloramphenicol biosynthesis.

Control of growth, secondary metabolism and sporulation in Streptomyces venezuelae ISP5230 by jadW 1, a member of the afsA family of γ-butyrolactone regulatory genes

Microbiology ◽  
2003 ◽  
Vol 149 (8) ◽  
pp. 1991-2004 ◽  
Author(s):  
Liru Wang ◽  
Leo C. Vining
Keyword(s):  
Growth Rate ◽  
Secondary Metabolism ◽  
Morphological Differentiation ◽  
Nitrogen Sources ◽  
Repeat Sequence ◽  
Antibiotic Biosynthesis ◽  
Wild Type ◽  
Streptomyces Venezuelae ◽  
New Genes ◽  
Insertional Inactivation

Three new genes (jadW 1, jadW 2 and jadW 3) were isolated from a region of the Streptomyces venezuelae ISP5230 chromosome at the left-hand end of the jad cluster for jadomycin B (JdB) biosynthesis. The deduced amino acid sequence of jadW 1 showed strong similarity to gene products associated in several streptomycetes with γ-butyrolactone autoregulators controlling morphological differentiation and secondary metabolism. Examination of JadW1 for conserved domains detected a repeat sequence characteristic of proteins in the AfsA regulatory family. Insertional inactivation of jadW 1 reduced the growth rate of S. venezuelae cultures in aerated liquid media containing complex nitrogen sources and altered growth morphology in minimal medium. It also affected sporulation on agar media. Cultures of jadW 1-disrupted mutants grown under conditions supporting biosynthesis of JdB or chloramphenicol by the wild-type strain failed to produce either of the antibiotics. Complementing the disrupted strain by transformation with pJV435, containing a cloned copy of the gene, improved sporulation and restored antibiotic biosynthesis in transformants to titres close to those of the wild-type similarly transformed with pJV435 as a control. The results are consistent with a role for jadW 1 in regulating morphological and metabolic differentiation. Further sequence analysis of jadR 2, which functions with jadR 1 in stress-induced activation of JdB biosynthesis, indicated that this gene encodes a γ-butyrolactone receptor homologue. The growth-rate-sensitive phenotype of the jadW 1-disrupted mutant, and the proximity of jadW 1 to jadR 2 indicate that this region of the jad gene cluster contains a regulatory mechanism incorporating γ-butyrolactone signalling and sensitivity to environmental stress.

Role of the carbon source in regulating chloramphenicol production by Streptomyces venezuelae: studies in batch and continuous cultures

1988 ◽  
Vol 34 (11) ◽  
pp. 1217-1223 ◽  
Author(s):  
R. K. Bhatnagar ◽  
J. L. Doull ◽  
L. C. Vining
Keyword(s):  
Carbon Source ◽  
Glucose Concentration ◽  
Specific Activity ◽  
Antibiotic Production ◽  
Enzyme Synthesis ◽  
Antibiotic Biosynthesis ◽  
Synthetase Activity ◽  
Streptomyces Venezuelae ◽  
Batch Cultures ◽  
Chemostat Cultures

Both carbon- and nitrogen-limited media that supported a biphasic pattern of growth and chloramphenicol biosynthesis were devised for batch cultures of Streptomyces venezuelae. Where onset of the idiophase was associated with nitrogen depletion, a sharp peak of arylamine synthetase activity coincided with the onset of antibiotic production. The specific activity of the enzyme was highest when the carbon source in the medium was also near depletion at the trophophase–idiophase boundary. In media providing a substantial excess of carbon source through the idiophase, the peak specific activity was reduced by 75%, although the timing of enzyme synthesis was unaltered. Morever, chemostat cultures in which the growth rate was limited by the glucose concentration in the input medium failed to show a decrease in specific production of chloramphenicol as the steady-state intracellular glucose concentration was increased. The results suggest that a form of "carbon catabolite repression" regulates synthesis of chloramphenicol biosynthetic enzymes during a trophophase–idiophase transition induced by nitrogen starvation. However, this regulatory mechanism does not establish the timing of antibiotic biosynthesis and does not function during nitrogen-sufficient growth in the presence of excess glucose.

Nitrogen metabolism and chloramphenicol production in Streptomyces venezuelae

1983 ◽  
Vol 29 (12) ◽  
pp. 1706-1714 ◽  
Author(s):  
S. Shapiro ◽  
L. C. Vining
Keyword(s):  
Growth Rate ◽  
Glutamate Dehydrogenase ◽  
Nitrogen Metabolism ◽  
Nitrogen Assimilation ◽  
Glutamate Synthase ◽  
Biomass Accumulation ◽  
Nitrogen Sources ◽  
Ph Control ◽  
Ammonium Nitrogen ◽  
Streptomyces Venezuelae

The relationship between chloramphenicol production and nitrogen metabolism in Streptomyces venezuelae was examined in stirred jar cultures under pH control. Nitrogen sources that supported rapid biomass accumulation gave low rates of antibiotic synthesis during growth. This was consistent with a general incompatibility between fast growth and high yields of chloramphenicol. In media where the growth rate was reduced below the attainable maximum by the rate at which nitrogen could be assimilated, chloramphenicol production was associated with biomass accumulation. Enzymes that are potentially associated with nitrogen assimilation pathways were assayed in cultures supplied with nitrogen sources supporting markedly different growth rates. The results indicated mat glutamine synthetase and alanine dehydrogenase levels were relatively insensitive to changes in growth rate and nitrogen source depletion. Glutamate dehydrogenase and glutamate synthase, on the other hand, showed high activity in cultures assimilating ammonium nitrogen and markedly decreased activity with poorer nitrogen sources or when ammonium was depleted. If chloramphenicol biosynthesis is coordinately controlled by mechanisms that regulate nitrogen assimilation, glutamate synthase and glutamate dehydrogenase are the most likely enzymes that manifest the regulatory linkage.

Physiological control of trophophase–idiophase separation in streptomycete cultures producing secondary metabolites

1995 ◽  
Vol 41 (4-5) ◽  
pp. 309-315 ◽  
Author(s):  
Xiaowen Liao ◽  
Leo C. Vining ◽  
Janice L. Doull
Keyword(s):  
Secondary Metabolites ◽  
Streptomyces Coelicolor ◽  
High Growth ◽  
Biomass Accumulation ◽  
Nitrogen Sources ◽  
Streptomyces Venezuelae ◽  
Physiological Control ◽  
Carbon And Nitrogen Sources ◽  
Carbon And Nitrogen ◽  
Defined Media

Cultures of Streptomyces coelicolor A3 (2) produced actinorhodin in defined media with various carbon and nitrogen sources. Production occurred during biomass accumulation if assimilation of either the carbon or the nitrogen source limited the rate of growth. High growth rates tended to delay product synthesis until after biomass accumulation was complete, but fully biphasic fermentation profiles were achieved only with media supporting very rapid growth. The onset of actinorhodin production then coincided with a decline in the growth rate during transition of carbon-sufficient cultures to stationary phase. In cultures with maltose as a growth-limiting carbon source, depletion of phosphate increased the rate of actinorhodin biosynthesis, but did not alter the timing of its initiation. With defined media, the use of spores rather than vegetative mycelium as inocula reduced the overlap between trophophase and idiophase. The general guidelines for achieving biphasic production of actinorhodin in S. coelicolor A3 (2) cultures could be used to obtain trophophase–idiophase separation in cultures of Streptomyces venezuelae producing chloramphenicol. However, the conditions needed to be modified to give optimized biphasic fermentations with individual strains. Under conditions favouring chloramphenicol production in a distinct idiophase, aromatic amine secondary metabolites in the same cultures of S. venezuelae were produced in a pattern that overlapped the trophophase, suggesting that conditions need to be tailored also to meet differences in the regulation of secondary metabolites.Key words: Streptomyces coelicolor A3 (2), Streptomyces venezuelae, actinorhodin, biphasic fermentations, chloramphenicol, inoculum shift down.

Hydroxylamines as One-Atom Nitrogen Sources for Metal-Catalyzed Cycloadditions

Synthesis ◽  
2021 ◽  
Author(s):  
Xinjun Luan ◽  
Jingxun Yu
Keyword(s):  
Transition Metal ◽  
Nitrogen Source ◽  
Nucleophilic Reagent ◽  
Nitrogen Sources ◽  
Short Review ◽  
Indole Derivatives ◽  
Electrophilic Amination ◽  
Intramolecular Cycloaddition ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

AbstractTransition-metal-catalyzed C–N bond formation is one of the most important pathways to synthesize N-heterocycles. Hydroxylamines can be transformed into a nucleophilic reagent to react with a carbon cation or coordinate with a transition metal; it can also become an electrophilic nitrogen source to react with arenes, alkenes, and alkynes. In this short review, the progress made on transition-metal-catalyzed cycloadditions with hydroxylamines as a nitrogen source is summarized.1 Introduction2 Cycloaddition To Form Aziridine Derivatives2.1 Intramolecular Cycloaddition To Form Aziridine Derivatives2.2 Intermolecular Cycloaddition To Form Aziridine Derivatives3 Cycloaddition To Form Indole Derivatives4 Cycloaddition To Form Other N-Heterocycles4.1 Aza-Heck-Type Amination Reactions4.2 Nitrene Insertion Amination Reactions4.3 Intramolecular Nucleophilic and Electrophilic Amination Reactions5 Conclusion and Outlook

scholarly journals Studies on the Role of the are a Gene in the Regulation of Nitrogen Catabolism in Aspergillus nidulans

1975 ◽  
Vol 28 (3) ◽  
pp. 301 ◽  
Author(s):  
MJ Hynes
Keyword(s):  
Nitrogen Source ◽  
Aspergillus Nidulans ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Selection Methods ◽  
Growth Responses ◽  
Dominance Relationships ◽  
Regulatory Circuits ◽  
Specific Activities

Mutants of Apergillus nidulanswith lesions in a gene, areA (formerly called amdT), have been isolated by a variety of different selection methods. The areA mutants show a range of pleiotropic growth responses to a number of compounds as sole nitrogen sources, but are normal in utilization of carbon sources. The levels of two amidase enzymes as well as urease have been investigated in the mutants and have been shown to be affected by this gene. Most of the areA mutants have much lower amidase-specific activities when grown in ammonium-containing medium, compared with mycelium incubated in medium la9king a nitrogen source. Some of the areA. mutants do not show derepression of urease upon relief of ammonium repression. The dominance relationships of areA alleles have been investigated in� heterozygous diploids, and these studies lend support to the proposal that areA codes for a positively acting regulatory product. One of the new areA alleles is partially dominant to areA + and areA102. This may be a result of negative complementation or indicate that areA has an additional negative reiuIatory function. Investigation.of various amdR; areA double mutants has led to the conclusion that amdR and areA participate in independent regulatory circuits in the control of acetamide utilizatiol1. Studies on an amdRc; areA.double mutant indicate that areA is involved in derepression of acetamidase upon relief of ammo.nium repression.

scholarly journals Varied Diazotrophies, Morphologies, and Toxicities of Genetically Similar Isolates of Cylindrospermopsis raciborskii(Nostocales, Cyanophyceae) from Northern Australia

2001 ◽  
Vol 67 (4) ◽  
pp. 1839-1845 ◽  
Author(s):  
Martin L. Saker ◽  
Brett A. Neilan
Keyword(s):  
Nitrogen Source ◽  
Growth Rates ◽  
Vegetative Cell ◽  
Nitrogen Sources ◽  
Water Bodies ◽  
Cylindrospermopsis Raciborskii ◽  
Rrna Gene ◽  
Northern Australia ◽  
Fixed Nitrogen ◽  
Freeze Dried

ABSTRACT The potentially toxic freshwater cyanobacteriumCylindrospermopsis raciborskii has become increasingly prevalent in tropical and temperate water bodies worldwide. This paper investigates the effects of different nitrogen sources (NO3 −, NH4 +, and omission of a fixed form of nitrogen) on the growth rates, morphologies, and cylindrospermopsin (CYL) concentrations (expressed as a percentage of the freeze-dried weight) of seven C. raciborskii isolates obtained from a range of water bodies in northern Australia and grown in batch culture. In general, growth rates were lowest in the absence of a fixed-nitrogen source and highest with NH4 + as the nitrogen source. Conversely, the highest concentrations of CYL were recorded in cultures grown in the absence of a fixed-nitrogen source and the lowest were found in cultures supplied with NH4 +. Cultures supplied with NO3 − were intermediate with respect to both CYL concentration and growth rate. Different nitrogen sources resulted in significant differences in the morphology of C. raciborskii trichomes. Most notable were the loss of heterocysts and the tapering of end cells in cultures supplied with NH4 + and the statistically significant increase in vegetative cell length (nitrogen depleted < NO3 − < NH4 +). The morphological changes induced by different nitrogen sources were consistent for all isolates, despite measurable differences in vegetative-cell and heterocyst dimensions among isolates. Such induced morphological variation has implications forCylindrospermopsis taxonomy, given that distinctions between species are based on minor and overlapping differences in cell lengths and widths. The close phylogenetic association among all seven isolates was confirmed by the high level (>99.8%) of similarity of their 16S rRNA gene sequences. Another genetic technique, analysis of the HIP1 octameric-palindrome repeated sequence, showed greater heterogeneity among the isolates and appears to be a useful method for distinguishing among isolates of C. raciborskii.

scholarly journals Mutants affecting histidine utilization inAspergillus nidulans

1975 ◽  
Vol 25 (2) ◽  
pp. 119-135 ◽  
Author(s):  
Meryl Polkinghorne ◽  
M. J. Hynes
Keyword(s):  
Carbon Source ◽  
Nitrogen Source ◽  
Sole Carbon Source ◽  
Nitrogen Sources ◽  
Limiting Factor ◽  
Sole Nitrogen Source ◽  
Wild Type ◽  
Exogenous Substrate ◽  
Growth Properties ◽  
Type Strains

SUMMARYWild-type strains ofAspergillus nidulansgrow poorly onL-histidine as a sole nitrogen source. The synthesis of the enzyme histidase (EC. 4.3.1.3) appears to be a limiting factor in the growth of the wild type, as strains carrying the mutantareA102 allele have elevated histidase levels and grow strongly on histidine as a sole nitrogen source.L-Histidine is an extremely weak sole carbon source for all strains.Ammonium repression has an important role in the regulation of histidase synthesis and the relief of ammonium repression is dependent on the availability of a good carbon source. The level of histidase synthesis does not respond to the addition of exogenous substrate.Mutants carrying lesions in thesarA orsarB loci (suppressor ofareA102) have been isolated. The growth properties of these mutants on histidine as a sole nitrogen source correlate with the levels of histidase synthesized. Mutation at thesarA andsarB loci also reduces the utilization of a number of other nitrogen sources. The data suggest that these two genes may code for regulatory products involved in nitrogen catabolism. No histidase structural gene mutants were identified and possible explanations of this are discussed.

OPTIMIZATION OF BIOVANILLIN PRODUCTION OF LEMONGRASS LEAVES HYDROLYSATES THROUGH PHANEROCHAETE CHRYSOSPORIUM

2015 ◽  
Vol 77 (31) ◽  
Author(s):  
Huszalina Hussin ◽  
Madihah Md Salleh ◽  
Chong Chun Siong ◽  
Muhammad Abu Naser ◽  
Suraini Abd- Aziz ◽  
...  
Keyword(s):  
Ferulic Acid ◽  
Nitrogen Source ◽  
Phanerochaete Chrysosporium ◽  
Organic Nitrogen ◽  
Nitrogen Sources ◽  
Optimum Conditions ◽  
Molar Yield ◽  
Primary Screening ◽  
Organic Nitrogen Source ◽  
Inorganic And Organic Nitrogen

The recent study has demonstrated the effects of different nitrogen sources on vanillin production by Phanerochaete chrysosporium. Primary screening supported maximum biotransformation of ferulic acid (from lemongrass leaves hydrolysate) to vanillin by using ammonium chloride and yeast extract as inorganic and organic nitrogen source, respectively. With the 2-level factorial analysis, the optimum conditions of vanillin production from ferulic acid by P. chrysosporium was achieved at 0.192g/L with a molar yield of 24.5%.

scholarly journals Biomass accumulation, photochemical efficiency of photosystem II, nutrient contents and nitrate reductase activity in young rosewood plants (Aniba rosaeodora Ducke) submitted to different NO3-:NH4+ ratios

2007 ◽  
Vol 37 (4) ◽  
pp. 533-541 ◽  
Author(s):  
Denize Caranhas de Sousa Barreto ◽  
José Francisco de Carvalho Gonçalves ◽  
Ulysses Moreira dos Santos Júnior ◽  
Andreia Varmes Fernandes ◽  
Adriana Bariani ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Nitrate Reductase ◽  
Growth Performance ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Photochemical Efficiency ◽  
Biomass Accumulation ◽  
Nitrate Content ◽  
Chl A ◽  
Culture Substrate

The rosewood (Aniba rosaeodora Ducke) is a native tree species of Amazon rainforest growing naturally in acidic forest soils with reduced redox potential. However, this species can also been found growing in forest gaps containing oxide soils. Variations in the forms of mineral nitrogen (NO3- or NH4+) may be predicted in these different edaphic conditions. Considering that possibility, an experiment was carried out to analyze the effects of different NO3-:NH4+ ratios on the growth performance, mineral composition, chloroplastid pigment contents, photochemical efficiency photosystem II (PSII), and nitrate redutase activity (RN, E.C.1.6.6.1) on A. rosaeodora seedlings. Nine-month-old seedlings were grown in pots with a washed sand capacity of 7.5 kg and submitted to different NO3-:NH4+ ratios (T1 = 0:100%, T2 = 25:75%, T3 = 50:50%, T4 = 75:25%, and T5 = 100:0%). The lowest relative growth rate was observed when the NO3-:NH4+ ratio was equal to 0:100%. In general, high concentrations of NO3- rather than NH4+ favored a greater nutrient accumulation in different parts of the plant. For the chloroplastid pigment, the highest Chl a, Chl b, Chl tot, Chl a/b and Chl tot/Cx+c contents were found in the treatment with 75:25% of NO3-:NH4+, and for Chl b and Cx+c it was observed no difference. In addition, there was a higher photochemical efficiency of PSII (Fv/Fm) when high NO3- concentrations were used. A linear and positive response for the nitrate reductase activity was recorded when the nitrate content increased on the culture substrate. Our results suggest that A. rosaeodora seedlings have a better growth performance when the NO3- concentrations in the culture substrate were higher than the NH4+ concentrations.

Sign in / Sign up

Export Citation Format

Share Document