Glucose-nitrate Medium Research Articles

Evaluation and detection of Brassicaceae leafy whey phytohormones efficacy for exploiting as a medium obtaining optimistic culture of fungi in vitro

The DPJ (Deproteinised Juice) or whey constituents were responsible for the induction of growth optimization of plants, various fungi including yeast, Rhizobium reported by earlier workers. In previous experiments, DPJ maximised the growth of plants and seed germination. During present investigation the carbohydrates, amino acids and protein tests were taken into the consideration. All the tests found positive. Despite, the extract is deproteinised, still there was persistence of few proteins and amino acids. The collection of mycelia grown on DPJ was filtered and the culture filtrates recommended to use in vitro for the industrial purpose for biomass and secondary metabolites. Experimental DPJ is compared with the glucose nitrate medium as control. These positive tests revealed the suitability of DPJ to be used as the medium for the growth of fungi. Positive amino acid tests conspicuously revealed presence of phytohormones in members of Brassicaceae DPJ and hence advisable to be utilised for the plant growth in vivo, plant callus growth and cell proliferation of mycelia in vitro.

IN VITRO SCREENING OF CELL WALL DEGRADING ENZYME PRODUCTIVITY FROM FUNGAL CULTURE FILTRATES ON DEPROTEINISED PLANT FLUID BY CUP PLATE ASSAY

The present study purpose is to evaluate the potentiality of the Deproteinised juice made from selected plants to induce the enzyme productivity by growing the fungi on it. It is because, in earlier findings, the DPJ was found potential in enhancing fungi and the plant growth when used as the medium. The internal factors are responsible in DPJ which induces plants and fungi growth. During the process of Green Crop Fractionation (GCF), the deproteinised (DPJ) obtained from tissues of cabbage, beet, lucerne (Alfalfa), carrot and Anathum (Dill) forages left after leaf protein extraction employed as a medium for the cultivation of mycelial biomass of Penicillium and Aspergillus fungi. The mycelial growth in vitro was compared with the glucose nitrate medium. The culture filtrates were used to screen different secreted hydrolytic or cell wall degrading enzymes.. The agar ‘cup‐plate’ diffusion technique has been applied to the quantitative determination of enzyme activity, principally to amylase, cellulase and protease. With all enzymes so far examined, the relationship between diameter of zone over a wide range secreted quantitatively was examined. All fungi grew well on DPJ in comparison to their growth on glucose nitrate (GN) medium. Comparatively with GN medium, lucerne DPJ was found having more mycelial cellular proliferation. When the fungi grown on different concentrations of substrates, enriched with carboxymethyl cellulose, casein and starch in deproteinised leaf extracts and GN medium, it was found that there was the enhancement in the mycelial dry weight grown on DPJ as compared with glucose nitrate medium. Penicillium showed more yield of enzyme activities especially of cellulases and amylases as compared to protease by cup plate method. There was enhancement of mycelial biomass when the concentrations of substrates increased from 1% to 2%, while there was no change in the activity of all enzymes by increasing the concentrations of substrates. Activities of the enzymes in vitro can be indicative of the pattern of organogenesis in callus cultures in further studies by fungal culture filtrates cultured on deproteinised fluid medium.

Profiling the Monascus pilosus Proteome during Nitrogen Limitation

Monascus species have the unique ability to economically produce many secondary metabolites. However, the influence of nitrogen limitation on Monascus secondary metabolite production and metabolic performance remains unclear. Varying the carbon/nitrogen (C/N) ratios in the range from 20 to 60 in cultivation of Monascus pilosus by glucose nitrate medium, our resulting data showed that red pigment production was significantly suppressed and more sensitive to nitrogen limitation than cellular biomass growth at a C/N ratio of 60. Using a comparative proteomic approach, combining two-dimensional gel electrophoresis, matrix-assisted laser desorption ionization time-of-flight/time-of-flight liquid chromatography-mass spectrometry, and tandem mass spectrometry, proteins with modified expression in the nitrogen-limited (C/N ratio 60) Monascus filamentous cells were identified. The results revealed that the deregulated proteins identified were involved in amino acid biosynthesis, protein translation, antioxidant-related enzymes, glycolysis, and transcriptional regulation. The results suggested that, under nitrogen limitation-induced suppression of protein translation and of expression of the related energy-generating enzymes, nitrogen limitation induced a switch of metabolic flux from glycolysis to the tricarboxylic acid (TCA) cycle for maintaining cellular energy homeostasis, resulting in repression of the metabolic shift of the polyketide biosynthesis pathway for red pigment production.

Chemical identification of N-acyl homoserine lactone quorum-sensing signals produced by Sinorhizobium meliloti strains in defined medium.

The N-acyl homoserine lactone (AHL) quorum-sensing signals produced by Sinorhizobium meliloti strains AK631 and 1021 when cultured in a defined glucose-nitrate medium were identified by gas chromatography/mass spectrometry (GC/MS) and electrospray ionization tandem mass spectrometry (ESI MS/MS). Both strains synthesized several long-chain AHLs. Defined medium cultures of strain AK631 synthesized a complex mixture of AHLs with short acyl side chains. Strain 1021 produced no short-chain AHLs when grown on defined medium and made a somewhat different set of long-chain AHLs than previously reported for cultures in rich medium. While the two strains produced several AHLs in common, the differences in AHLs produced suggest that there may be significant differences in their patterns of quorum-sensing regulation.

NarK enhances nitrate uptake and nitrite excretion in Escherichia coli

narK mutants of Escherichia coli produce wild-type levels of nitrate reductase but, unlike the wild-type strain, do not accumulate nitrite when grown anaerobically on a glucose-nitrate medium. Comparison of the rates of nitrate and nitrite metabolism in cultures growing anaerobically on glucose-nitrate medium revealed that a narK mutant reduced nitrate at a rate only slightly slower than that in the NarK+ parental strain. Although the specific activities of nitrate reductase and nitrite reductase were similar in the two strains, the parental strain accumulated nitrite in the medium in almost stoichiometric amounts before it was further reduced, while the narK mutant did not accumulate nitrite in the medium but apparently reduced it as rapidly as it was formed. Under conditions in which nitrite reductase was not produced, the narK mutant excreted the nitrite formed from nitrate into the medium; however, the rate of reduction of nitrate to nitrite was significantly slower than that of the parental strain or that which occurred when nitrite reductase was present. These results demonstrate that E. coli is capable of taking up nitrate and excreting nitrite in the absence of a functional NarK protein; however, in growing cells, a functional NarK promotes a more rapid rate of anaerobic nitrate reduction and the continuous excretion of the nitrite formed. Based on the kinetics of nitrate reduction and of nitrite reduction and excretion in growing cultures and in washed cell suspensions, it is proposed that the narK gene encodes a nitrate/nitrite antiporter which facilitates anaerobic nitrate respiration by coupling the excretion of nitrite to nitrate uptake. The failure of nitrate to suppress the reduction of trimethylamine N-oxide in narK mutants was not due to a change in the level of trimethylamine N-oxide reductase but apparently resulted from a relative decrease in the rate of anaerobic nitrate reduction caused by the loss of the antiporter system.

Conidiogenesis and secondary metabolism in Penicillium urticae.

Submerged cultures of Penicillium urticae (NRRL 2159A) produced the antibiotics patulin and griseofulvin when grown in a glucose-nitrate medium. A high concentration of calcium (i.e., 68 mM) inhibited the production of both antibiotics while stimulating conidiogenesis. Conidial mutants that were defective in an early stage of conidiogenesis produced markedly less patulin, even under growth conditions that favored secondary metabolism. A mutant which lacked the ability to produce the patulin pathway metabolites m-cresol, toluquinol, m-hydroxybenzyl-alcohol, m-hydroxybenzaldehyde, gentisaldehyde, gentisyl alcohol, gentisic acid and patulin, as well as the pathway enzyme m-hydroxybenzyl-alcohol dehydrogenase, still produced yields of conidia that were equivalent to or greater than those of the parent strain. Other mutants which were blocked at later steps of the patulin pathway also produced conidia. These results indicate that patulin and the other related secondary metabolites noted above are not a prerequisite to conidiogenesis in P. urticae. Environmental and developmental factors such as calcium levels and conidiogenesis do, however, indirectly affect the production of patulin pathway metabolites.

Synchronous initiation and maturation of Aspergillus niger conidiophores in culture

Synchronous development of Aspergillus niger conidiophores was obtained by using a system in which complete development was divided into four distinct morphogenetic stages, (i) Conidiophore initiation occurred in a low nitrogen (LN) medium, but not in a medium in which both glucose and nitrogen were exhausted simultaneously and not in LN medium under oxygen-limited conditions, (ii) Conidiophore growth occurred without exogenous nitrogen although exogenous glucose was essential. In addition, development was enhanced by a colonial growth form indicating that translocation from mycelium to the conidiophore was an important feature of this stage. During stages (i) and (ii) there was the abundant production of a carotenoid pigment, (iii) Vesicle and phialide formation did not occur on conidiophores formed in LN medium. Transfer of aborted conidiophores to a medium containing a nitrogen source and a tricarboxylic acid cycle intermediate as a carbon source stimulated vesicle and phialide formation. There was a concurrent stimulation of respiration and an increase in RQ, value. Conidiospore formation was inhibited and this resulted in vesicle and phialide proliferations, (iv) Heavy conidiospore production occurred on a further transfer of conidiophores with vesicles and phialides to a glucose nitrate medium. Conidiophore initiation, vesicle and phialide formation and carotene production were inhibited by reduction of the oxygen supply rate although vegetative growth could continue.

Carbon metabolism and morphogenesis of Aspergillus fonsecaeus. II. Nutritional status of culture filtrate and dissimilation by mycelial mat.

Culture filtrates ofA. fonsecaeus after its growth on glucose nitrate medium were studied for their nutritional status. It was found that culture filtrates support only the vegetative growth. This led to the conclusion that conditions for vegetative growth are different from those of asexual reproduction in this fungus.

Glucose and nitrate utilisation by anaerobic cultures of Ps. aeruginosa.

SUMMARYPs. aeruginosa was grown under anaerobic conditions in a synthetic glucose nitrate medium. In the presence of nitrate, carbon dioxide and cellular carbon were the end products of glucose metabolism. The nitrate was reduced almost entirely to gaseous nitrogen or nitrous oxide (18 p.c. of utilised NO3‐N). Continued incubation of anaerobic cultures after the exhaustion of the nitrate did very little to alter the end products of nitrate utilisation, but striking variations were recorded for the glucose utilisation. Up to 11 p.c. of the utilised glucose carbon was recovered as volatile and non‐volatile organic acids. The non‐volatile acids included extensive amounts of lactic and glycollic acids together with smaller quantities of succinic, malic, fumaric, citric, α keto glutaric and oxalacetic acids. The volatile acid was produced in approximately the same quantity in both aerated and anaerobic cultures whether nitrate was present or not. Carbon balances of 100 p.c. were obtained for the anaerobic cultures, but extensive discrepancies in the aerated culture indicated the formation of other undetected end products of glucose metabolism.

The physiology of sporulation in Penicillium griseofulvum Dierckx

The conditions for sporulation of Penicillium griseofulvum were investigated. Sporulation does not occur in submerged culture in a glucose-nitrate medium but can be induced (in appropriate conditions) by the following methods: transfer of mycelium to aerial conditions, increasing the concentration of sugar in the medium, addition of calcium, copper, or crude glucose, partial desiccation of the mycelium, transfer of mycelium to nitrogen-free medium. P. griseofulvum may be induced to sporulate at a very early stage of germination but not before it has assimilated some external nitrogen. Induction of sporulation can be reversed by adding assimilable nitrogen sufficiently soon after induction. Sporulation of four other species of Penicillium and two species of Aspergillus was induced by some, but not all, of the conditions found effective for Penicillium griseofulvum.

Thiamine, its intermediates and growth ofCorticium microsclerotia (Matz) Weber

A pure culture of the fungusCorticium microsclerotia (Matz) Weber, obtained from the Centraalbureau voor Schimmelcultures, Baarn, Holland, was found to be thiamine heterotrophic, when cultured on a glucose nitrate medium.