共查询到20条相似文献,搜索用时 31 毫秒
1.
Chovanec P Kalinák M Liptaj T Pronayová N Jakubík T Hudecová D Varecka L 《Canadian journal of microbiology》2005,51(10):853-862
Trichoderma viride was capable of growth and conidiation in the presence of high concentrations of the uncoupler 3,3',4',5-tetrachlorosalicylanilide (up to 100 micromol x L(-1) and of the respiration inhibitor mucidin (up to 100 micromol x L(-1) ) in both submerged and surface cultivation. When vegetative mycelia were cultivated on the solid Czapek-Dox medium with yeast autolysate under an anaerobic and CO2-containing atmosphere, the growth was observed only rarely but the microorganism survived as long as 3 months under these conditions. Major products of metabolism of both aerobic and anaerobic submerged mycelia were identified by means of 1H-NMR measurements. Major products excreted to the medium under aerobic conditions were succinic and citric acids. Major metabolites present in the submerged mycelia were gamma-aminobutyric (and glutamic) acid and alanine. Under anaerobic conditions, citric acid was not excreted into the medium but ethanol appeared. Its production could not be increased upon increasing the sugar concentration. The appearance of secondary metabolites was found to be modified by oxygen availability during the mycelial growth. Results suggest that the vegetative form of T. viride is capable of fermentative metabolism characterized by the production of ethanol and succinate and that the excretion of carboxylic acids is developmentally regulated and modified by oxygen availability. 相似文献
2.
Identical masses of submerged Trichoderma viride mycelia of various ages were used as inoculum for a second submerged cultivation lasting for 24 h. It was found that the
growth yield of secondary culture was dependent on the age of inoculum. The growth yields increased when the age of primary
culture was less than 3 d, and decreased down to zero when older mycelia were inoculated. The mycelia were living even after
1 month of submerged cultivation, as they formed conidia after inoculating onto solid medium. In order to elucidate underlying
biochemical processes, developmental changes of specific activities of organellar marker enzymes were measured in the mitochondrial/vacuolar
and microsomal fractions of mycelia. These activities changed during the growth of mycelia in a biphasic manner and their
time courses were remarkably similar. Only the H+-ATPase activity decreased monophasically with the age of mycelia. Membrane-bound proteases of both membrane fractions changed
differently upon ageing. These results could not be explained as a consequence of nutrient starvation and indicate that the
prolonged submerged cultivation triggers coordinated series of biochemical events which leads to the loss of growth competence. 相似文献
3.
Hadeer Lazim Nedra Slama Houda Mankai Insaf Barkallah Ferid Limam 《World journal of microbiology & biotechnology》2010,26(7):1317-1322
Streptomyces rimosus CN08 isolated from Tunisian soil produced 8.6 mg l−1 of oxytetracycline (OTC) under submerged fermentation (SmF). Attempts were made for enhancing OTC production after irradiation-induced
mutagenesis of Streptomyces rimosus CN08 with Co60-γ rays. 125 OTC-producing colonies were obtained after screening on kanamycin containing medium. One mutant called Streptomyces rimosus γ-45 whose OTC production increased 19-fold (165 mg l−1) versus wild-type strain was selected. γ-45 mutant was used for OTC production under solid-state fermentation (SSF). Wheat
bran (WB) was used as solid substrate and process parameters influencing OTC production were optimized. Solid-state fermentation
increased the yield of antibiotic production (257 mg g−1) when compared with submerged fermentation. Ammonium sulphate as additional nitrogen source enhanced OTC level to 298 mg g−1. Interestingly, OTC production by γ-45 mutant was insensitive to phosphate which opens the way to high OTC production even
in medium containing phosphate necessary for optimal mycelia growth. 相似文献
4.
Penicillium simplicissimum excreted citrate, isocitrate, and succinate when grown in a strongly buffered medium [1 M Mes (pH 6) or 1 M Hepes (pH 7.3)].
Growth in a weakly buffered medium did not lead to citrate excretion despite a similar intracellular citrate concentration.
When nongrowing, citrate-excreting hyphae were aerated in a glucose solution, the following steady-state intracellular concentrations
of organic acids were measured: succinate (25 mM); citrate, isocitrate, malate, and fumarate (all less than 5 mM). After 2
h of incubation, the extracellular concentrations of these acids were [μmol (g dry wt.)–1]: isocitrate [100], citrate [60], succinate [30], and malate, fumarate, and α-ketoglutarate [<5]. The excretion of citrate
was due neither to an unspecific change in the permeability of the plasma membrane nor to simple diffusion of undissociated
citric acid. The involvement of a transport protein in citrate excretion was indicated because N-ethylmaleimide and sodium azide inhibited citrate excretion strongly despite an unchanged outward-directed citrate gradient.
Arguments are given why efflux via a citrate uptake carrier is not considered probable. These results indicate that citrate
is excreted by P. simplicissimum via a transport protein that probably specifically mediates the efflux of citrate.
Received: 28 July 1997 / Accepted: 19 November 1997 相似文献
5.
The effect of Ca2+ on mycelial growth in Terfezia boudieri was studied. Terfezia boudieri Chatin (Ascomycotinae) occurs in mycorrhizal association with Helianthemum shrubs in deserts with calcareous soils. External Ca2+ stimulated mycelial growth in both liquid media and solidified substrates. The response to Ca2+ was very faint in well-aerated culture but pronounced in mycelia immersed in the medium, indicating dependence on mycelial aeration. 2,4-Dinitrophenol (DNP), an inhibitor of oxidative phosphorylation, and succinate, a potential cytoplasm acidifier, inhibited mycelial growth but enhanced the stimulatory effect of Ca2+. This effect was reduced by the Ca2+ channel blocker verapamil. 相似文献
6.
Görgens JF van Zyl WH Knoetze JH Hahn-Hägerdal B 《Applied microbiology and biotechnology》2005,67(5):684-691
Supplementation of a chemically defined medium with amino acids or succinate to improve heterologous xylanase production by a prototrophic Saccharomyces cerevisiae transformant was investigated. The corresponding xylanase production during growth on ethanol in batch culture and in glucose-limited chemostat culture were quantified, as the native ADH2 promoter regulating xylanase expression was derepressed under these conditions. The addition of a balanced mixture of the preferred amino acids, Ala, Arg, Asn, Glu, Gln and Gly, improved both biomass and xylanase production, whereas several other individual amino acids inhibited biomass and/or xylanase production. Heterologous protein production by the recombinant yeast was also improved by supplementing the medium with succinate. The production of heterologous xylanase during growth on ethanol or glucose could thus be improved by supplementing metabolic precursors in the carbon- or nitrogen-metabolism. 相似文献
7.
Marcelo Rodrigues de Melo Luzia Doretto Paccola-Meirelles Terezinha de Jesus Faria Noemia Kazue Ishikawa 《Mycoscience》2009,50(1):78-81
Enokipodins A, B, C, and D are α-cuparene-type sesquiterpenoids antimicrobial metabolites produced in the stationary stage
of Flammulina velutipes mycelia development in malt extract broth. This study assessed the influence of nutritional and environmental factors on
F. velutipes mycelia culture for the production of these metabolites. The mycelia growth and antimicrobial activity were assessed by determining
dry matter and the diffusion in agar method, respectively. The best F. velutipes mycelia growth was observed in dextrose potato broth, and greater antimicrobial metabolite production occurred in complete
Pontecorvo’s culture medium. Environmental modifications, such as a rise in temperature from 25° to 37°C on the 15th day of
F. velutipes mycelia culture in malt extract and peptone broth, also optimized antimicrobial metabolite production. The metabolites produced
in these treatments were correlated with the enokipodins A and B in thin-layer chromatography (TLC) and the antifungal activity
test by TLC bioautography. This study showed that there was no correlation between biomass production and antimicrobial metabolite
production, but there may be a correlation between culture medium composition and enokipodins biosynthesis. 相似文献
8.
Wood-decay fungi depend upon recycling of nitrogen-containing molecules to maintain growth in nitrogen-deficient environments. One of the pools that can support growth in these organisms is the pool of free amino acids. The free amino acid (AA) composition of Schizophyllum commune mycelium grown on the surface of nitrogen-rich (M = 6.6 mM L-asparagine) and nitrogen-poor medium (M01 = 0.06 mM L-asparagine) has been examined: When mycelium is grown on M, alanine, glutamate, and asparagine account for almost 2/3 of the amino acid pool. The free amino acid concentration is reduced by 75% for mycelium grown on the M01 medium, with alanine and glutamate predominating. In addition, free NH4+ increases by 60% in nitrogen-deprived mycelia. Except for asparagine, which is absorbed by the apices, the concentration of all free amino acids is higher in the centers of M-grown, 4-day-old mycelia than in the apices. Hyphae grown to exponential growth on M and transferred to M01 for 12 h show greater free amino acid and NH4+ concentrations in the apices, most likely indicating increased translocation to the apices. 相似文献
9.
Murakawa Shigeo Izaki Kazuo Takahashi Hajime 《Bioscience, biotechnology, and biochemistry》2013,77(13):2487-2493
To investigate the stereo-specificity and the genetic control of a succinate transport system, mutants of Escherichia coli defective in the transport of succinate were isolated. The mutants showed no detectable growth on fumarate and malate, as well as on succinate. All of the revertant strains from one of the transport defective mutants, T5, could grow either on succinate, fumarate or malate. The T5 cells accumulated only a trace amount of 14C-succinate or 14C-fumarate. These results indicated that at least succinate, fumarate, and malate were transported by the system involving the same component. From the competition experiments, it was suggested that oxalacetate was also transported by the same system. A partial participation of this system for the transport of aspartate was suggested. 相似文献
10.
11.
Dattatray Bedade Jan Deska Sandip Bankar Samir Bejar Rekha Singhal Salem Shamekh 《Preparative biochemistry & biotechnology》2013,43(6):549-555
AbstractTruffles are symbiotic hypogeous edible fungi (form of mushroom) that form filamentous mycelia in their initial phase of the growth cycle as well as a symbiotic association with host plant roots. In the present study, Tuber maculatum mycelia were isolated and tested for extracellular amylase production at different pH on solid agar medium. Furthermore, the mycelium was subjected to submerged fermentation for amylase production under different culture conditions such as variable carbon sources and their concentrations, initial medium pH, and incubation time. The optimized conditions after the experiments included soluble starch (0.5% w/v), initial medium pH of 7.0, and incubation time of 7 days, at room temperature (22?±?2?°C) under static conditions which resulted in 1.41?U/mL of amylase. The amylase thus obtained was further characterized for its biocatalytic properties and found to have an optimum activity at pH 5.0 and a temperature of 50?°C. The enzyme showed good thermostability at 50?°C by retaining 98% of the maximal activity after 100?min of incubation. The amylase activity was marginally enhanced in presence of Cu2+ and Na+ and slightly reduced by K+, Ca2+, Fe2+, Mg2+, Co2+, Zn2+, and Mn2+ ions at 1?mM concentration. 相似文献
12.
Eugene Bolton Brian Higgisson Aiden Harrington Fergal O'Gara 《Archives of microbiology》1986,144(2):142-146
The role of the dicarboxylic acid transport (dct) system in the Rhizobium meliloti-Alfalfa symbiosis was investigated. Mutants of R. meliloti CM2 unable to grow on medium containing succinate as the sole carbon source were isolated following chemical and transposon mutagenesis. These mutants were also unable to utilize malate or fumarate as the sole source of carbon. Transport studies with 14C-labelled succinate showed that the mutants were specifically defective in succinate transport. Revertants of both chemical and transposon mutants were obtained at a frequency of 10-5–10-6. The R. meliloti dct mutants were able to nodulate Alfalfa plants but the nodules formed were unable to fix nitrogen. Revertants of the mutants were fully effective on plants. The mutants unable to transport succinate were used to isolate dct genes from a R. meliloti gene bank. Two plasmids containing a common 26.5 Mdal insert were found to complement some of the mutants. The presence of this DNA insert in the complementing mutant strains restored their effectivenss of plants. This DNA fragment encoding succinate transport function(s) was used to produce genetically engineered R. meliloti strains with an increased rate of succinate uptake.Abbreviation dct
dicarboxylic acid transport 相似文献
13.
The fungus Sclerotium rolfsii is presently under development as a bioherbicide for broadleaf weed species using fungus-infested substrates as application material in this laboratory. The effect of environmental factors and three precursors (citric acid, ascorbic acid, and sodium succinate) on mycelial growth, oxalic acid production, and virulence by SC64 in liquid culture were investigated. The results showed that for mycelia growth the optimum liquid medium was Modified Richard's solution (MRS) among the five tested media, but potato dextrose broth (PDB) produced the maximum oxalic acid production and virulence on detached Solidago canadensis leaves. When PDB was used as the basic medium, the oxalic acid/mycelial dry weight (mg g–1) ratio reached the peak 4 days after inoculation. The optimum temperature for oxalic acid production was at 27°C, but increased mycelial dry weight and virulence were observed at 30°C. The optimum range of initial pH value for oxalic acid accumulation was 4.0–6.0, with the optimal pH 5.0; highest mycelial growth was with an initial pH 3.5–6.0 (optimum pH 5.0) and subsequently pH 3.5–5.5 (maximum at pH 3.5). Both mycelial dry weight and oxalic acid production showed a decreasing trend as a result of the precursor of oxalic acid being added to PDB. Among the three precursors, the greatest decrease in mycelial dry weight, and oxalic acid production was caused by sodium succinate. This clarification of optimal conditions for production of mycelial biomass while insuring high concentrations of oxalic acid and high virulence should be useful for further development of this fungus as biocontrol agent. 相似文献
14.
Selection procedure for deregulated iron transport mutants (fur) in Escherichia coli K 12: fur not only affects iron metabolism 总被引:19,自引:0,他引:19
Klaus Hantke 《Molecular & general genetics : MGG》1987,210(1):135-139
Summary A selection procedure using Mn2+ is described. A high percentage of the Mn2+ resistant mutants had constitutive iron transport systems. By P1 transduction, and complementation with the cloned fur gene it could be shown that nearly all the mutants constitutive in the expression of the operon fusion fiu::placMu were only defective in fur. High concentrations of manganese inhibited the derepression of an iron-regulated lac operon fusion. In another iron-regulated lac operon fusion that was inducible by iron, manganese also induced the production of -galactosidase. Most of the fur mutants isolated (80%) were not able to grow on succinate, fumarate or acetate. After transformation with a fur
+ plasmid all 39 mutants tested were able to grow on succinate. In fur mutants the presence of succinate in the growth medium reduced succinate uptake rates by 50%–70%. Succinate dehydrogenase activity was reduced to 10% of that of the parent strain. 相似文献
15.
A. G. Shugaev N. A. Shugaeva D. A. Lashtabega E. I. Vyskrebentseva 《Russian Journal of Plant Physiology》2010,57(2):189-197
The effect of substitution of KCl for sucrose in the reaction medium on succinate oxidation and hydrogen peroxide generation
was investigated in the mitochondria isolated from stored taproots of sugar beet (Beta vulgaris L.). In a sucrose-containing medium, oxidation of succinate was inhibited by oxaloacetate; this inhibition was especially
pronounced upon a decrease in substrate concentration and eliminated in the presence of glutamate, which removed oxaloacetate
in the course of transamination. Irrespective of succinate concentration, substitution of KCl for sucrose in the medium considerably
enhanced suppression of succinate oxidation apparently as a result of slow activation of succinate dehydrogenase (SDH) by
its substrate. In this case, mitochondria showed the symptoms of uncoupling, lower values of membrane potential (ΔΨ), respiratory
control (RC), and ADP/O induced by electrophoretic transport of potassium via K+ channel of mitochondria. KCl-dependent suppression of succinate oxidation by taproot mitochondria was accompanied by a considerable
inhibition of H2O2 production as compared with the sucrose-containing medium. These results indicate that in the presence of potassium ions,
ΔΨ dissipates, suppression of succinate oxidation by oxaloacetate increases, and succinate-dependent generation of ROS in
sugar beet mitochondria is inhibited. A possible physiological role of oxaloacetate-restricted SDH activity in the suppression
of respiration of storage organs protecting mitochondria from oxidative stress is discussed. 相似文献
16.
Qiang Li Dan Wang Yong Wu Maohua Yang Wangliang Li Jianmin Xing Zhiguo Su 《Journal of microbiology (Seoul, Korea)》2010,48(3):290-296
Succinic acid is one of the platform compounds and its production via natural feedstocks has drawn worldwide concerns. To
evaluate the inhibitory effects of fermentation products on the growth of Actinobacillus succinogenes 130ZT and Escherichia coli NZN111, AFP111, BL21, fermentations with addition of individual products in medium were carried out. The cell growth was
inhibited when the concentrations of formate, acetate, lactate, and succinate were at range of 8.8–17.6 g/L, 10–40 g/L, 9–18
g/L, and 10–80 g/L, respectively. For these two species of bacteria, E. coli was more resistant to acid products than A. succinogenes, while both endured succinate rather than by-products. As a result of end product inhibition, succinate production yield
by A. succinogenes decreased from 1.11 to 0.49 g/g glucose. Logistic and Monod mathematical models were presented to simulate the inhibition
kinetics. The Logistic model was found more suitable for describing the overall synergistic inhibitory effects. 相似文献
17.
Streptomyces fradiaewas immobilized in polyacrylamide gel prepared from 5% total acrylamide (90% acrylamide and 10%N,N′-methylenebisacrylamide). Production of protease by the immobilized mycelia was attempted in a batch system. A dilute medium containing 0.5% starch, 0.5% meat extract, and 0.05% yeast extract was employed. The reusability of the immobilized and washed mycelia was examined. The activity of protease production by washed mycelia was rapidly decreased with increasing use cycles. The activity of the immobilized mycelia increased gradually, and reached a maximum after ten use cycles. Then, the activity gradually decreased with increasing reaction cycles. This might be caused by destruction of the gels. On the other hand, the sterilization of the surface of the immobilized mycelia was effective for elongation of the lifetime. As a result, the half-life of protease production by the sterilized immobilized mycelia was about 30 days. The rate of protease production by immobilized mycelia was 12,000 U/ml/hr. This value was four times higher than that by submerged culture. 相似文献
18.
María Guadalupe Maldonado-Blanco Johanna Lizzette Gallegos-Sandoval Gabriela Fernández-Peña Carlos Francisco Sandoval-Coronado Myriam Elías-Santos 《Biocontrol Science and Technology》2014,24(2):180-189
Three Metarhizium anisopliae and three Beauveria bassiana isolates were cultivated in media containing casamino acids, soybean flour or sunflower seed flour and were shaken for three days. M. anisopliae presented similar yields of around 106 submerged spores/ml without significant differences among them, whereas B. bassiana produced yields of around 108 spores/ml, of which GHA strain produced more submerged spores in the casamino acids medium. The other two strains showed no significant difference in the production of submerged spores in the three media used. Differences in mortality on Aedes aegypti larvae were observed with the submerged spores of Metarhizium depending on isolate and medium used. M. anisopliae 2157 caused significantly higher mortality (40%) when cultivated in casamino acids medium. It presented an LC50 of 8.93 × 105 submerged spores/ml water against mosquito larvae five days after application, whereas it caused 27% mortality in Ae. aegypti adults 10 days after application. In conclusion, fungal nutrition affected virulence of some isolates of M. anisopliae against Ae. aegypti larvae while such an effect was not noted for B. bassiana isolates. 相似文献
19.
Amani Briki Karim Kabor Eric Olmos Sabine Bosselaar Fabrice Blanchard Michel Fick Emmanuel Guedon Frantz Fournier Stphane Delaunay 《Engineering in Life Science》2020,20(5-6):205-215
Corynebacterium glutamicum is well known as an important industrial amino acid producer. For a few years, its ability to produce organic acids, under micro‐aerobic or anaerobic conditions was demonstrated. This study is focused on the identification of the culture parameters influencing the organic acids production and, in particular, the succinate production, by this bacterium. Corynebacterium glutamicum 2262, used throughout this study, was a wild‐type strain, which was not genetically designed for the production of succinate. The oxygenation level and the residual glucose concentration appeared as two critical parameters for the organic acids production. The maximal succinate concentration (4.9 g L?1) corresponded to the lower kLa value of 5 h?1. Above 5 h?1, a transient accumulation of the succinate was observed. Interestingly, the stop in the succinate production was concomitant with a lower threshold glucose concentration of 9 g L?1. Taking into account this threshold, a fed‐batch culture was performed to optimize the succinate production with C. glutamicum 2262. The results showed that this wild‐type strain was able to produce 93.6 g L?1 of succinate, which is one of the highest concentration reported in the literature. 相似文献
20.
Corynebacterium glutamicum, an established industrial amino acid producer, has been genetically modified for efficient succinate production from the renewable carbon source glucose under fully aerobic conditions in minimal medium. The initial deletion of the succinate dehydrogenase genes (sdhCAB) led to an accumulation of 4.7 g l?1 (40 mM) succinate as well as high amounts of acetate (125 mM) as by‐product. By deleting genes for all known acetate‐producing pathways (pta‐ackA, pqo and cat) acetate production could be strongly reduced by 83% and succinate production increased up to 7.8 g l?1 (66 mM). Whereas overexpression of the glyoxylate shunt genes (aceA and aceB) or overproduction of the anaplerotic enzyme pyruvate carboxylase (PCx) had only minor effects on succinate production, simultaneous overproduction of pyruvate carboxylase and PEP carboxylase resulted in a strain that produced 9.7 g l?1 (82 mM) succinate with a specific productivity of 1.60 mmol g (cdw)?1 h?1. This value represents the highest productivity among currently described aerobic bacterial succinate producers. Optimization of the production conditions by decoupling succinate production from cell growth using the most advanced producer strain (C. glutamicumΔpqoΔpta‐ackAΔsdhCABΔcat/pAN6‐pycP458Sppc) led to an additional increase of the product yield to 0.45 mol succinate mol?1 glucose and a titre of 10.6 g l?1 (90 mM) succinate. 相似文献