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 Growth responses of aquatic hyphomycetes to different sources of carbon and nitrogen

2013 ◽  
Vol 5 (2) ◽  
pp. 313-317 ◽  
Author(s):  
Saraswati Bisht
Keyword(s):  
Carbon Sources ◽  
Nitrogen Sources ◽  
Dry Weight ◽  
Maximum Growth ◽  
Fungal Species ◽  
Aquatic Hyphomycetes ◽  
Growth Responses ◽  
Carbon And Nitrogen ◽  
Fungal Isolates ◽  
Different Sources

Assessment of different sources of carbon and nitrogen in terms of dry weight biomass of four selected aquatic hyphomycetes viz; Flagellospora penicilloides Ingold, Pestalotiopsis submersus Sati and Tiwari, Tetrachaetum elegans Ingold and Tetracladium marchalianum De Wildeman was made for their nutritional requirements. Eight carbon sources and ten nitrogen sources were singly added to the basal media in order to provide 4g of carbon and 1g of nitrogen per litre of distilled water. Among carbon compounds glucose and sucrose were found to be most suitable sources of carbon for all the four fungal isolates, where as fructose proved good for T. marchalianum, P. submersus and F.penicilloides fairly. Cellulose was found a poor source of carbon for the growth of all these isolates. The inorganic sources of nitrogen were found as good nitrogen sources with preference for ammonium ions. Suitability of amino acids was found variable from species to species for nitrogen. T.elegans and T.marchalianum had their maximum growth in asparagines, whereas, P. submersus had their highest growth in proline. Cysteine was observed as a good source of nitrogen for almost all the fungal isolates used. Anova calculated for these observed data showed significant variations in the dry weight production of different fungal species grown in different sources of carbon and nitrogen(P<0.01).

scholarly journals Lipid and Carotenoid Production by Rhodotorula glutinis with a Combined Cultivation Mode of Nitrogen, Sulfur, and Aluminium Stress

2019 ◽  
Vol 9 (12) ◽  
pp. 2444 ◽  
Author(s):  
Nora Elfeky ◽  
Mostafa Elmahmoudy ◽  
Yue Zhang ◽  
JianLi Guo ◽  
Yongming Bao
Keyword(s):  
Nitrogen Source ◽  
High Performance ◽  
Lipid Synthesis ◽  
Rhodotorula Glutinis ◽  
Nitrogen Sources ◽  
Synthesis Rate ◽  
Carotenoid Production ◽  
Total Pigment ◽  
Relative Productivity

Torulene is a promising pink pigment, produced only by yeasts and fungi, and its production is still in a developing stage due to the low production rate. Accordingly, this study focuses on maximizing torulene production by Rhodotorula glutinis using shaken flask fermentation. The effect of different nitrogen sources, and C/N and C/S ratios on lipid and carotenoid production by R. glutinis was studied using 60 g/L glucose. The largest cells filled with golden fluorescence lipid bodies were observed using fluorescence microscopy when peptone was used as a nitrogen source. The highest total pigment (0.947 mg/L) and carotenoid relative productivity (Car-RP) (89.04 µg/g) were obtained at C/N 146 and C/S 120, and with ammonium sulfate as a nitrogen source, with 62% torulene domination using High Performance Liquid Chromatography (HPLC) for identification. Under a high C/N ratio, regardless of the C/S ratio, the carotenoid synthesis rate decreased after three days while the lipid synthesis rate kept increasing to the sixth day. Interestingly, after adding 0.7 mM Al2(SO4)3 to the optimized medium, the total pigment and Car-RP (2.2 mg/L and 212.9 µg/g) sharply increased, producing around 2.16 mg/L torulene (98%) with around 50% decrease in lipid yield. This is the first report on the role of Al2(SO4)3 for enhancing torulene production under lipogenesis condition, which could be used as a potential tool for torulene production.

scholarly journals Amino Acid Catabolism by an areA-Regulated Gene Encoding an l-Amino Acid Oxidase with Broad Substrate Specificity in Aspergillus nidulans

2005 ◽  
Vol 71 (7) ◽  
pp. 3551-3555 ◽  
Author(s):  
Meryl A. Davis ◽  
Marion C. Askin ◽  
Michael J. Hynes
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Substrate Specificity ◽  
Nitrogen Source ◽  
Aspergillus Nidulans ◽  
Nitrogen Sources ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
Broad Substrate Specificity ◽  
Strong Growth

ABSTRACT The filamentous fungus Aspergillus nidulans can use a wide range of compounds as nitrogen sources. The synthesis of the various catabolic enzymes needed to breakdown these nitrogen sources is regulated by the areA gene, which encodes a GATA transcription factor required to activate gene expression under nitrogen-limiting conditions. The areA102 mutation results in pleiotropic effects on nitrogen source utilization, including better growth on certain amino acids as nitrogen sources. Mutations in the sarA gene were previously isolated as suppressors of the strong growth of an areA102 strain on l-histidine as a sole nitrogen source. We cloned the sarA gene by complementation of a sarA mutant and showed that it encodes an l-amino acid oxidase enzyme with broad substrate specificity. Elevated expression of this enzyme activity in an areA102 background accounts for the strong growth of these strains on amino acids that are substrates for this enzyme. Loss of function sarA mutations, which abolish the l-amino acid oxidase activity, reverse the areA102 phenotype. Growth tests with areA102 and sarA mutants show that this enzyme is the primary route of catabolism for some amino acids, while other amino acids are metabolized through alternative pathways that yield either ammonium or glutamate for growth.

Nutritional and environmental factors affecting growth and sporulation of Sporidesmium sclerotivorum

1981 ◽  
Vol 27 (7) ◽  
pp. 685-691 ◽  
Author(s):  
E. A. Barnett ◽  
W. A. Ayers
Keyword(s):  
Nitrogen Source ◽  
Agar Medium ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Mineral Salts ◽  
Factors Affecting ◽  
Carbon And Nitrogen ◽  
Naoh Solution ◽  
Casamino Acids ◽  
Nutritional Studies

Three of five isolates of Sporidesmium sclerotivorum, a mycoparasite of Sclerotinia spp., grew well on an agar medium containing mineral salts, glucose, thiamine, and glutamine or Casamino acids as the nitrogen source. The nitrogen requirement for two of the isolates was satisfied by NH4Cl, Casamino acids, or glutamine. Glutamine was the best single nitrogen source. Only one isolate, CS-1, was used in further nutritional studies. The optimum concentration of glutamine for growth was 5 g/L. Glucose, mannose, mannitol, and cellobiose were excellent carbon sources. A glucose concentration of 20 g/L was optimum. Mannitol supported greater growth than glucose with Casamino acids as the nitrogen source but glucose was the superior carbon source with glutamine as the nitrogen source. Greatest growth was achieved with a combination of these carbon and nitrogen sources. Sporidesmium sclerotivorum, isolate CS-1, required thiamine for growth and sporulation. Biotin stimulated growth. The fungus developed maximally within the range of pH 5.0–5.5 and growth was greatly reduced at a pH below 4.0 or above 6.0. Control of acidity by the periodic addition of NaOH solution permitted substantially increased growth. The optimum temperature for growth was 22.5–25.0 °C but production of macroconidia was greatest at 15–20 °C.

Growth, nutrition, and proteolytic activity of the sap-staining fungus Ophiostoma piceae

1993 ◽  
Vol 71 (9) ◽  
pp. 1224-1230 ◽  
Author(s):  
L. D. Abraham ◽  
A. Roth ◽  
J. N. Saddler ◽  
C. Breuil
Keyword(s):  
Nitrogen Source ◽  
Proteolytic Activity ◽  
Inorganic Nitrogen ◽  
Carbon Sources ◽  
Fungal Growth ◽  
Nitrogen Sources ◽  
Soluble Starch ◽  
Minimal Growth ◽  
Inorganic Nitrogen Source ◽  
Ophiostoma Piceae

The sap-staining ascomycete Ophiostoma piceae strain 387N used ammonium, but not nitrate, as an inorganic nitrogen source. Organic nitrogen sources assimilated included bovine serum albumin, collagen, acid-hydrolyzed casein, urea, and various amino acids. Sucrose, glucose, maltose, raffinose, and soluble starch were suitable carbon sources. The optimum temperature for growth was near 23 °C, with an upper limit at 35 °C and minimal growth at 4 °C after 3 days. An initial pH of 6.1 yielded the greatest biomass. Proteolytic activity was greatest in cultures supplemented with protein as the nitrogen source, but some activity was detected in cultures with no assimilable source of nitrogen. Proteinases were detected throughout growth in protein-supplemented liquid media, and they appeared to hydrolyze azocoll, with optimal activity at pH 8. Isoelectric focusing gels of culture filtrates, obtained after fungal growth on protein supplemented media, showed a major proteolytic band focusing at pH 5.2. Key words: staining fungi, Ophiostoma, nutrition, biomass, proteinases.

Role of Temperature and Flow in Biomass Transporting in Porous Media

2012 ◽  
Vol 178-181 ◽  
pp. 80-87
Author(s):  
Jing Jing Huang ◽  
Cheng Yuan Zhang
Keyword(s):  
Carbon Sources ◽  
Nitrogen Sources ◽  
Water Source ◽  
Seepage Flow ◽  
Underground Water ◽  
Heat Pumps ◽  
Living Environment ◽  
Hot Water ◽  
Lower Temperature

Underground water source heat pumps system is an underground geothermal technology that extracts underground water as a lower temperature heat source, and recharged into the same aquifer after heat exchanger. During the recharging process, not only external microorganisms such as bacteria but also a variety of contaminants ( for example carbon sources, nitrogen sources, the growth inhibitors/promoters and so on) would get into the aquifer to affect the aquifer's living environment for microbial, which would affect the quality of underground water directly or indirectly. Not only that, the extraction and injection of underground hot water would cause the redistribution of temperature, which would then affect the growth of microorganisms as a key affecter. And the biomass would be transported by seepage flow in way of advection and conduction mainly. Based on the background of underground water source heat pumps system, the coupling of three-field (temperature-hydraulic-microbial) is analyzed, and a corresponding coupled THB model is obtained. Taking Escherichia coli as target organisms in the aquifer, the distribution of biomass various with time and space are obtained respectively. The temperature and advection sensitivity of microbial concentration is also acquired. It is showed that the growth of microbial plays a great role in the process of its transportation, and the concentration of microbial would increase significantly when the local temperature increased or the convection strength decreased while other effects stay the same.

Effects of sulfur and different sources and levels of nitrogen and energy on the intake and liveweight change of steers fed tropical native pasture hay

1989 ◽  
Vol 29 (2) ◽  
pp. 157 ◽  
Author(s):  
SR McLennan ◽  
MD Savage ◽  
JA Lindsay ◽  
PK O'Rourke ◽  
RM Murray
Keyword(s):  
Nitrogen Source ◽  
Nitrogen Sources ◽  
Control Group ◽  
Meat And Bone Meal ◽  
Bone Meal ◽  
Protein Meal ◽  
Rumen Degradation ◽  
Low Protein ◽  
Native Pasture

Weaner steers were fed low quality native pasture hay in pens for 84 days to determine the differences in response to supplements of molasses (280 g/steer.day) and grain sorghum (265 g/steer.day), fed with urea (45 g/steer.day), and to determine the role of sulfur in these differences. The control group consumed 1.63 kg/steer.day organic matter (OM) and lost 277 g/steer.day over the feeding period. Supplements of urea alone or urea + grain did not affect hay intake or liveweight performance but both parameters were markedly improved by supplements of urea + molasses and urea + sodium sulfate. It was concluded that sulfur, in addition to urea, was necessary to increase feed intake and reduce liveweight loss in steers fed the low-protein pasture hay. With an increase in molasses intake from 280 to 1120 g/ steer.day, total OM intake remained constant while roughage OM intake declined (P> 0.05). At the higher molasses intake both roughage and total OM intakes were greater when 37 g/steer.day of supplemental nitroin-was fed (P>0.05), suggesting that energy substitution could be countered by ensuring a non-limiting nitrogen supply. Urea, meat and bone meal or the combination of the 2 were equally effective as the nitrogen source. In a second experiment weaner steers were fed a similar hay in pens for 56 days to compare the effects of either urea or protein meal as the nitrogen source in molasses. Molasses was fed at 1120 g/steer.day. The protein meal was a formaldehyde-treated mix of cottonseed meal, meat and bone meal and fish meal (8:1:1). Unsupplemented animals consumed 2.86 kg/ steer.day OM and lost 210 g/steer.day liveweight. Total OM intake was increased similarly by both nitrogen sources (P<0.05) but, whereas steers fed urea-molasses maintained weight, those given urea molasses plus the formaldehyde-treated protein meal gained weight at 163 g/steer.day (P<0.05). The advantage of providing a protein source protected from rumen degradation was demonstrated.

scholarly journals Effects of nitrogen and carbon sources on the production of inulinase from strain Bacillus sp. SG113

2016 ◽  
Vol 3 (1) ◽  
pp. 69-74
Author(s):  
Simeon Gavrailov ◽  
Viara Ivanova
Keyword(s):  
Nitrogen Source ◽  
Organic Nitrogen ◽  
Inorganic Nitrogen ◽  
Carbon Sources ◽  
Casein Hydrolysate ◽  
Jerusalem Artichoke ◽  
Nitrogen Sources ◽  
Cellular Growth ◽  
Bacillus Sp ◽  
Carbon And Nitrogen

Abstract The effects of the carbon and nitrogen substrates on the growth of Bacillus sp. SG113 strain were studied. The use of organic nitrogen sources (peptone, beef extract, yeast extract, casein) leads to rapid cellular growth and the best results for the Bacillus strain were obtained with casein hydrolysate. From the inorganic nitrogen sources studied, the (NH4) 2SO4 proved to be the best nitrogen source. Casein hydrolysate and (NH4) 2SO4 stimulated the invertase synthesis. In the presence of Jerusalem artichoke, onion and garlic extracts as carbon sources the strain synthesized from 6 to 10 times more inulinase.

scholarly journals Effects of Nitrogen and Carbon Sources on Transcription of Soluble Methyltransferases in Methanosarcina mazei Strain Gö1

2005 ◽  
Vol 187 (17) ◽  
pp. 6147-6154 ◽  
Author(s):  
Katharina Veit ◽  
Claudia Ehlers ◽  
Ruth A. Schmitz
Keyword(s):  
Nitrogen Source ◽  
Degradation Products ◽  
Molecular Nitrogen ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Initial Step ◽  
Conclusive Evidence ◽  
Carbon And Nitrogen ◽  
Methanosarcina Mazei ◽  
Or Genes

ABSTRACT The methanogenic archaeon Methanosarcina mazei strain Gö1 uses versatile carbon sources and is able to fix molecular nitrogen with methanol as carbon and energy sources. Here, we demonstrate that when growing on trimethylamine (TMA), nitrogen fixation does not occur, indicating that ammonium released during TMA degradation is sufficient to serve as a nitrogen source and represses nif gene induction. We further report on the transcriptional regulation of soluble methyltransferases, which catalyze the initial step of methylamine consumption by methanogenesis, in response to different carbon and nitrogen sources. Unexpectedly, we obtained conclusive evidence that transcription of the mtmB2C2 operon, encoding a monomethylamine (MMA) methyltransferase and its corresponding corrinoid protein, is highly increased under nitrogen limitation when methanol serves as a carbon source. In contrast, transcription of the homologous mtmB1C1 operon is not affected by the nitrogen source but appears to be increased when TMA is the sole carbon and energy source. In general, transcription of operons encoding dimethylamine (DMA) and TMA methyltransferases and methylcobalamine:coenzyme M methyltransferases is not regulated in response to the nitrogen source. However, in all cases transcription of one of the homologous operons or genes is increased by TMA or its degradation products DMA and MMA.

scholarly journals Bacterial Degradation of Cyanide and Its Metal Complexes under Alkaline Conditions

2005 ◽  
Vol 71 (2) ◽  
pp. 940-947 ◽  
Author(s):  
Víctor M. Luque-Almagro ◽  
María-J. Huertas ◽  
Manuel Martínez-Luque ◽  
Conrado Moreno-Vivián ◽  
M. Dolores Roldán ◽  
...  
Keyword(s):  
Metal Complexes ◽  
Nitrogen Source ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Degradation Pathway ◽  
Alkaline Media ◽  
Bacterial Degradation ◽  
16S Rna ◽  
Alkaline Conditions ◽  
Cyanide Degradation

ABSTRACT A bacterial strain able to use cyanide as the sole nitrogen source under alkaline conditions has been isolated. The bacterium was classified as Pseudomonas pseudoalcaligenes by comparison of its 16S RNA gene sequence to those of existing strains and deposited in the Colección Española de Cultivos Tipo (Spanish Type Culture Collection) as strain CECT5344. Cyanide consumption is an assimilative process, since (i) bacterial growth was concomitant and proportional to cyanide degradation and (ii) the bacterium stoichiometrically converted cyanide into ammonium in the presence of l-methionine-d,l-sulfoximine, a glutamine synthetase inhibitor. The bacterium was able to grow in alkaline media, up to an initial pH of 11.5, and tolerated free cyanide in concentrations of up to 30 mM, which makes it a good candidate for the biological treatment of cyanide-contaminated residues. Both acetate and d,l-malate were suitable carbon sources for cyanotrophic growth, but no growth was detected in media with cyanide as the sole carbon source. In addition to cyanide, P. pseudoalcaligenes CECT5344 used other nitrogen sources, namely ammonium, nitrate, cyanate, cyanoacetamide, nitroferricyanide (nitroprusside), and a variety of cyanide-metal complexes. Cyanide and ammonium were assimilated simultaneously, whereas cyanide strongly inhibited nitrate and nitrite assimilation. Cyanase activity was induced during growth with cyanide or cyanate, but not with ammonium or nitrate as the nitrogen source. This result suggests that cyanate could be an intermediate in the cyanide degradation pathway, but alternative routes cannot be excluded.

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