Effect of aeration efficiency and carbon source on the production of anthracyclines inStreptomyces galilaeus

Biosynthesis of anthracyclines inStreptomyces galilaeus during submerged cultivation is considerably influenced by aeration and by the concentration of glucose in the medium. At higher values of oxygen absorption rate both the production of ε-pyrromycinone glycosides in the wild strain JA 3043 and its production mutant G-167 and accumulation of free ε-pyrromycinone in the blocked mutant G-162 were found to be higher; the production of 7-deoxyaglycones was lower in all strains. The studied strains differed in the rate of glucose consumption and in the ability to utilize starch for the biosynthesis of anthracyclines. A two-fold concentration of glucose in the medium resulted in the G-162 strain in an increase of the yield of ε-pyrromycinone by 120 %. The production of glycosides in strain G-167 increased even after exhaustion of glucose from the medium and the amount of 7-deoxyaglycones simultaneously decreased.     

The effects of cultural conditions on growth and secondary metabolism in Streptomyces thermoviolaceus

Abstract Granaticin, an isochromate quinone antibiotic is synthesized as a secondary metabolite by Streptomyces thermoviolaceus . Antibiotic productivity was investigated under a variety of cultural conditions, including complex and defined media, mesophilic and thermophilic temperatures and a variety of sole carbon sources. In a defined medium growth was supported, to varying extents, by different carbon sources and in most cases granaticin production was observed. Highest biomass and granaticin yields were obtained when cultures were grown in the presence of xylan, fructose, glutamate or proline as carbon source. Changes in pH during growth affected both the timing and extent of granaticin production.     

Phytic acid-mediated regulation of secondary metabolism in Streptomyces thermoviolaceus grown in simple and complex media

Primary and secondary metabolism in the thermophilic actinomycete Streptomycesthermoviolaceus were found to be strongly regulated by phosphate in complexand defined media. Increasing phosphate levels in glutamate minimal salts media led to peakproduction of granaticin at 5 mmol phosphate, a concentration that was growth-limiting, beforetotal inhibition of antibiotic production at 50 mmol. Product formation in particulate rapeseedmeal-based media was found to be less affected by the initial phosphate concentration. Theaddition of 5 mmol phytic acid to proline minimal salts media led to an increase in theconcentration of phosphate optimal for antibiotic production from 5·7 mmol to 15 mmol andreduced inhibition at higher concentrations. Phytic acid was shown to bind phosphate fromminimal salts media and inhibit the growth of the organism at high concentrations. Differences inthe production of granaticin by S. thermoviolaceus in two rapeseed meal-derived mediawere shown to be phosphate and phytic acid-related. In particulate rapeseed, the additionalphosphate from minimal salts media was predominantly bound in an organic-soluble complex,while in extracted rapemeal media, phosphate was present predominantly in the free form.Overall, the work suggests that reduction in growth rate,which can be brought about by a varietyof factors including low phosphate concentrations,is the critical factor for the onset of secondarymetabolism in S.thermoviolaceus.     

Involvement of aeration in carbon source regulation of cephem antibiotic biosynthesis inStreptomyces clavuligerus

Summary The interference by glycerol and other carbon sources with production of cephem antibiotics by resting cells ofStreptomyces clawligerus was found to be related to aeration conditions. When a low cell density or increased aeration was used, carbon sources did not have any effect on the rate of production.     

Effect of carbon source on enzymes involved in glycerol metabolism inNeurospora crassa

Specific activities of eight enzymes involved in glycerol metabolism were determined in crude extracts of three strains ofNeurospora crassa after growth on six different carbon sources. One of the strains was wild type, which grew poorly on glycerol as sole carbon source; the other two were mutant strains which were efficient glycerol utilizers. A possible basis for this greater effeciency of glycerol utilization was catabolite repression of glyceraldehyde kinase by glycerol in wild type, and two-fold higher glycerate kinase activity in the mutant strains after growth on glycerol, thus apparently allowing two routes for glyceraldehyde to enter the glycolytic pathway in the mutant strains but only one in wild type. The preferential entry of glyceraldehyde to the glycolytic pathway through glycerate was suggested by the lack of glyceraldehyde kinase in all three strains after growth on one or more of the carbon sources and the generally higher levels of aldehyde dehydrogenase and of glycerate kinase than of glyceraldehyde kinase.     

The effects of temperature, pH and growth rate on secondary metabolism in Streptomyces thermoviolaceus grown in a chemostat.

Streptomyces thermoviolaceus was grown in a chemostat under conditions of glutamate limitation. The effects of growth rate on production of the antibiotic granaticin, extracellular protein and protease activity as components of secondary metabolism were studied at 37, 45 and 50 degrees C. The amount of each secondary metabolite synthesized was highly dependent on growth rate and temperature. Granaticin yields were highest at growth rates of 0.1 to 0.15 h-1 at 37 degrees C, 0.175 h-1 at 45 degrees C and 0.045 h-1 at 50 degrees C. Protease activity of culture supernatants responded to low nutrient concentration and/or low growth rate. Measurements of extracellular protein revealed complex changes in amount which were dependent on growth rate and temperature. At 45 degrees C and a growth rate of 0.15 h-1, biomass yield was highest between pH 5.5 to 6.5 whereas granaticin synthesis was low at pH 5.5 and rose to highest values at between pH 6.5 and 7.5.     

Carbon source nutrition of rapamycin biosynthesis inStreptomyces hygroscopicus

Summary Chemically-defined media were developed for rapamycin production byStreptomyces hygroscopicus. Thirty-five carbon sources were tested for their effect on production. Eight failed to support growth and seven appeared to repress or inhibit rapamycin formation. The best combination of two carbon sources were 2% fructose and 0.5% mannose. Acetate and propionate, which are known to contribute most of the carbon atoms of the lactone ring, were unsatisfactory for growth and/or rapamycin production.This paper is dedicated to Professor Herman Jan Phaff in honor of his 50 years of active research which still continues.     

Effect of carbon source on compost nitrogen and carbon losses

The effect of C source on N losses by volatilization during composting was measured using four bulking agents, each at three humidity levels and composted in duplicate under passive and active aeration. The bulking agents were pine shavings alone and corrected with soybean, chopped grass hay alone and corrected with urea, long (unchopped) wheat straw and chopped oat straw. The readily available C of each bulking agent was determined by analyzing for BOD5. In 105 l laboratory vessels, the bulking agents were mixed with liquid swine manure and tap water for a C/N of 20 and three humidity levels of 60%, 65% and 70%. While being aerated actively or passively, the mixtures were composted for 21 days. Their initial and final C and N contents were measured to conduct a mass balance analysis and calculate C and N losses. C and N losses were compared to bulking agent BOD5. N losses were compared to C losses. The humidity level and aeration regime had no effect on C and N losses but the N losses were correlated to C losses and only the C losses could be correlated to the BOD5 of the bulking agent. Thus, the N losses are related not only to the availability of C but also to the extent of composting. A relationship established between N and C losses indicated that 85% of the initial total N of the compost was available for microbial degradation and that 70% of the available C was lost as CO2 during the immobilization process.     

Effect of an increased sink demand on the carbon metabolism and export of a maize source leaf

The sink demand was increased on a source maize leaf ( Zea mays L. cv. F7F2) by darkening all the leaves except the fourth, which was maintained under the prevailing irradiance conditions. The parameters of carbon metabolism were measured precisely during the first hours, and then daily during one week. The ambient photosynthetic activity and the maximum photosynthetic capacity were not altered by the treatment but the soluble carbohydrate and starch contents diminished, while ADP-glucose pyrophosphorylase (EC 2.7.7.27) activity increased. The carbon export rate, evaluated by the rate of disappearance of radioactivity after a 1-min ¹⁴CO₂ pulse, was faster than in control leaves. A compartmental analysis of the time course of ¹⁴C export further indicated that the sucrose pool providing the export flux was largely increased by the dark treatment. The darkened leaf 5, taken as an example of the darkened sources, was completely depleted of its carbohydrate content after one day in the dark and remained devoid of carbohydrates during the following week.     

Effect of oxidative stress on rat thyrocyte iodide metabolism

Thyroid cells fall into the type of cells functioning during continuous production of high H(2)O(2) concentrations. We studied the effect of H(2)O(2)-induced oxidative stress (0.1, 1.0 and 10.0 mM) on the activities of the key steps of iodide metabolism (uptake, oxidation and organification) in thyrocytes cultivated in an organ culture. After 60 min cultivation of cells in a medium containing H(2)O(2) at concentrations of 1.0 and 10.0 mM iodide (I(-)) uptake, thyroperoxidase (TPO) activity and I(-) organification were completely inhibited. No restoration of the parameters studied was observed within the subsequent 24 h of cultivation. The inhibitory effect of 0.1 mM H(2)O(2) was reversible. Activation of I(-) uptake in the cultivated tissue and a 520-880% increase of the total I(-) content were observed after 8 and 24 h. The concentration of I(-) protein-bound fraction was raised by 220% after 24 h. A biphasic effect of 0.1 mM H(2)O(2) on TPO was observed: 76.2% and 72.2% inhibitions were seen after 2 and 8 h, respectively, whereas 40.0% enzyme activation was after 5 h. TPO activity was partially restored after 24 h and amounted to 65% of the initial value. The significant increase in the concentration of iodide protein-bound fraction, which was observed simultaneously with TPO inhibition, could be due to thyroglobulin non-enzymic iodination under H(2)O(2)-generated oxidative stress. The data obtained indicate that iodide oxidation, as a step in the biosynthesis of thyroid hormones, was most sensitive to oxidative stress activation. The impaired iodide uptake and its organification during oxidative stress can play a pathogenetic role in disturbed functions of thyroid cells.     

地膜覆盖对旱作春玉米农田土壤微生物碳源代谢的影响

土壤微生物碳源代谢特征是评价土壤质量变化的重要指标。依托山西省东部晋中市寿阳县农业环境与作物高效用水科学观测试验站,采用Biolog-ECO微孔板技术探究覆膜（FM）与裸地不覆膜处理（LD）对旱作春玉米拔节期、灌浆期和收获期3个关键生育期不同土层深度下（0-10 cm、10-20 cm和20-30 cm）土壤微生物碳源代谢的影响。结果表明：1） FM措施可以显著增加土壤微生物对碳源的利用能力,显著提高了土壤微生物的优势度指数,但降低了土壤微生物的均匀度指数。2）在0-10 cm和10-20 cm土层,FM与LD处理土壤微生物碳源利用情况均表现为灌浆期较高,而20-30 cm土层,表现为收获期较高,差异均主要体现在碳水类、羧酸类、氨基酸类3大类碳源上。3）拔节期和灌浆期0-10 cm土层中FM处理的土壤微生物碳源利用能力显著高于LD处理;然而收获期0-10 cm土层中恰好相反,呈现出LD处理下土壤微生物碳源利用能力显著高于FM处理。4）此外,Pearson相关分析表明,FM处理土壤微生物对碳水类碳源和羧酸类碳源2大类碳源的利用能力主要与土壤有机碳（SOC）和全氮（TN）含量相关性较好,呈现出正相关关系;对氨基酸类碳源的利用能力主要与土壤含水量、pH、SOC、NH₄⁺-N和NO₃^--N含量相关性较好。LD处理下,土壤微生物对碳水类、羧酸类和氨基酸类碳源的利用能力与土壤中TN含量的相关性较好,且呈现正相关关系。     

Effect of altered sink: source ratio on photosynthetic metabolism of source leaves

When seven crop species were grown under identical environmental conditions, decreased sink:source ratio led to a decreased photosynthetic rate within 1 to 3 days in Cucumis sativus L., Gossypium hirsutum L., and Raphanus sativus L., but not in Capsicum annuum L., Solanum melongena L., Phaseolus vulgaris L., or Ricinus communis L. The decrease was not associated with stomatal closure. In cotton and cucumber, sink removal led to an increase in starch and sugar content, in glucose 6-phosphate and fructose 6-phosphate pools, and in the proportion of ¹⁴C detected in sugar phosphates and UDPglucose following ¹⁴CO₂ supply. When mannose was supplied to leaf discs to sequester cytoplasmic inorganic phosphate, promotion of starch synthesis, and inhibition of CO₂ fixation, were observed in control discs, but not in discs from treated plants. Phosphate buffer reduced starch synthesis in the latter, but not the former discs. The findings suggest that sink removal led to a decreased ratio inorganic phosphate:phosphorylated compounds. In beans ¹⁴C in sugar phosphates increased following sink removal, but without sucrose accumulation, suggesting tighter feedback control of sugar level. Starch accumulated to higher levels than in the other plants, but CO₂ fixation rate was constant for several days.     

Effect of DL-ethionine on the biosynthesis of anthracyclines inStreptomyces coeruleorubidus

Summary Inhibitory action of DL-ethionine on 4-0-methylation and 10-COOH-esterification of the anthracyclinone ring inStreptomyces coeruleorubidus causes the formation of substances of the carminomycinone series, a concomitant drop in the production of daunomycinone derivatives and suppression of the biosynthesis of -rhodomycinone. The extent of inhibition depends on inhibitor concentration and the time of its addition to cultures. Ho formation of anthracyclinone ethyl-derivatives was found.     

Effect of vitamin E on the oxidative metabolism of macrophages

The oxidative metabolism of macrophages in vitamin E deficiency was studied on Aug-Lac strain rats. Vitamin E deficiency was shown to enhance luminol-dependent chemiluminescence of macrophages stimulated by opsonized zymosan. There was also an increase in microviscosity of macrophage membrane lipid phase, that was estimated with a fluorescent probe. The incubation of macrophages with dl-alpha-tocopherol led to the inhibition of macrophage chemiluminescence. Superoxide dismutase, glutathione peroxidase and glutathione reductase activity was not affected by vitamin E deficiency.     

Effect of carbon source on aroma production byTrichoderma viride

Summary The effect of carbon source on aroma production by a strain ofTrichoderma viride was studied in static and agitated cultures. Different carbon sources affected the quantity but not the nature of the aroma chemical produced. The formation of the aroma lactone (6-pentyl--pyrone) was also affected by the method of cultivation.

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Resumen Se estudió el efecto de la fuente de carbono en la producción de aromas porTrichoderma viride en cultivos estáticos y en agitación. Las distintas fuentes de carbono utilizadas influyeron en la cantidad pero no en la naturaleza del aroma químico producido. En la formación de un aroma de tipo lactona (6-pentil--pirona) también influyó el método de cultivo.

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Résumé L'effet de la source de carbone sur la production d'arome par une souche deTrichoderma viride a été étudiée en cultures statitiques et agitées. Les différentes sources de carbone modifient la quantité, mais pas la nature chimique, de l'arome produit. La production de l'arome lactonique (6-pentyl--pyrone) est affectée aussi par le mode culture.

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Paper presented at the VII International Conference on the Global Impacts of Applied Microbiology, Helsinki, 12–18 August 1985     

Effect of carbon monoxide on metabolism and ultrastructure of carboxydobacteria

Growth of Seliberia carboxydohydrogena was inhibited by CO at 10 to 40% (v/v), resulting in increased substrate utilization and enhanced synthesis of cytochromes and cyclopropane and saturated fatty acids. The bacteria showed increased formation of new membrane structures, with pronounced folding of their cell walls.     

Further studies on the metabolism of phospholipids inStreptomyces griseus: Turnover of phospholipid moieties

Phospholipid turnover inStreptomyces griseus was studied by pulse-chase techniques using 1-[¹⁴C]sodium acetate and [U-¹⁴C]glucose. Different phospholipids and their individual moieties were found to have different turnover rates. The moieties of inositol-containing phospholipids exhibited the fastest turnover rates among the major phospholipids, while only fatty acyl moieties of phosphatidylethanolamine showed rapid turnover. Cardiolipin did not show any significant turnover with both precursors.     

甲烷菌对厌氧真菌不同碳源代谢的影响

【目的】探讨碳源和甲烷菌对厌氧真菌碳代谢的影响。【方法】利用体外批次厌氧发酵法,比较厌氧真菌纯培养(Orpinomyces sp.和Neocallimastix sp.)及其与甲烷菌共培养(F1:Orpinomyces sp.+Methanobrevibacter sp.和N3:Neocallimastix sp.+Methanobrevibacter sp.)发酵不同类型碳水化合物代谢产物的差异。【结果】对厌氧真菌和甲烷菌共培养F1和N3的研究显示,F1发酵木薯粉[(26.44±0.22)mmol/L]的乳酸产量是发酵玉米芯[(1.31±0.04)mmol/L]的20.18倍,是N3发酵木薯粉[(1.59±0.03)mmol/L]的16.63倍,玉米芯[(0.79±0.08)mmol/L]的33.47倍。当F1和N3中的厌氧真菌纯培养时,各组乳酸产量均1.90 mmol/L。对F1进一步研究,结果显示发酵体系中木薯粉添加量在0.8%–2.0%之间时,乳酸产量随木薯粉添加量增加而增加。当含量在1.0%–2.4%之间时,随木薯粉添加量增加,甲烷和乙酸产量逐渐降低。比较F1发酵大米粉、木薯粉、玉米粉、小麦粉和土豆粉的发酵结果,发现乳酸产量与底物中支链淀粉的含量成正相关(R2=0.9554)。当F1发酵葡萄糖和麦芽糖时,乳酸产量5.00 mmol/L。当以麦芽糊精为底物时,乳酸产量高达(28.00±0.95)mmol/L。【结论】本文首次报道碳源和甲烷菌能够增强厌氧真菌的乳酸代谢途径并且这种增强存在种属特异性。     

Effect of trazodone on oxidative metabolism of rat brain in vitro

Oxygen uptake of rat brain homogenate was reduced by 1 mM trazodone, a new atypical antidepressant. Na,K-ATPase activity and the associated oxygen consumption of rat brain slices were also reduced. Oxygen consumption of rat brain slices was enhanced by dopamine and this effect was blocked by 0.0001 mM trazodone. This drug uncoupled oxidative phosphorylation.     

碳源对产紫青霉产菊粉酶的影响

试验不同碳源对产紫青霉菊粉酶生产情况的影响。结果表明,果糖、菊糖、菊芋浸汁作为碳源是菊粉酶生产较理想的诱导因子,但过量的果糖会产生阻遏。经菊糖作为主要碳源和唯一碳源筛选的菌株产酶能力可提高6－7倍。同时在发酵前期加入易利用的碳源培养菌体,后期利用菊糖诱导酶的产生,可使酶产量提高2倍。