Enhancement of diepoxin ζ production by yeast extract and its fractions in liquid culture of Berkleasmium-like endophytic fungus Dzf12 from Dioscorea zingiberensis

This study was to examine the effects of yeast extract (YE) and its fractions (YE1 and YE2) on the growth and diepoxin ζ (a spirobisnaphthalene with a diversity of bioactivities) production in liquid culture of Berkleasmium-like endophytic fungus Dzf12 from Dioscorea zingiberensis. When YE was applied to the liquid medium at 10 g/L on day 3 of culture, the diepoxin ζ production was most effectively enhanced 3.2-fold (378.70 mg/L versus 120.09 mg/L in control) after another 10 days culture. Feeding with 15 g/L of YE on day 9, the mycelia biomass reached 16.44 g/L, about 2.3-fold in comparison with the control (7.15 g/L). The polysaccharide fraction (YE1) was mainly responsible for stimulating diepoxin ζ accumulation, and the non-polysaccharide fraction (YE2) was mainly responsible for promoting mycelia growth. The results showed that the diepoxin ζ production in liquid culture of endophyte Dzf12 could be effectively enhanced by YE and its fractions.     

Toxicities of dicyanobenzofurazans with formation of superoxide in Escherichia coli

The toxicities of some benzofurazans (BZs), benzofurazan (1), 4,7-dimethylbenzofurazan (2), 4,7-dibromobenzofurazan (3), 4-bromo-6-cyanobenzofurazan (4), 4,7-dicyanobenzofurazan (5) and 4,5-dicyanobenzofurazan (6), were examined on Escherichia coli. Compound 5 at 4 microM and compound 6 at 7 microM completely inhibited the growth of E. coli in a simple nutritionally restricted medium (GM medium). These compounds were more toxic in GM medium than in a nutritionally rich medium (YE medium), which contained yeast extract as an additive in GM medium. Compound 4 also inhibited the growth of E. coli at 300 microM in GM medium. The toxicities of BZs were in the order of 1 approximately 2 approximately 3 less than 4 approximately 5 approximately 6. Compounds 4, 5 and 6 induced manganese-superoxide dismutase (Mn-SOD) and catalase activities of E. coli in YE medium. The induced SOD and catalase provide a defense against the potential cytotoxicities of O2- and H2O2. The rate of dioxygen uptake in cyanide-resistant respiration of E. coli was dependent on the concentration of 5, and was correlated with the induction of SOD and catalase. The reduction potentials of BZs followed the order of 1 approximately 2 less than 3 less than 4 less than 5 approximately 6. Compounds 5 and 6, which had redox potentials higher than those of the other BZs, are thought to be more readily reduced in the living system.(ABSTRACT TRUNCATED AT 250 WORDS)     

Supplementation of Methionine Enhanced the Ergothioneine Accumulation in the <Emphasis Type="Italic">Ganoderma neo-japonicum</Emphasis> Mycelia

The methods for increasing the production of ergothioneine (ERG) were investigated by using the mycelial culture of several mushroom species, primarily Ganoderma neo-japonicum. We first found that ERG was accumulated at the different levels in mycelia and fruiting bodies, respectively, depending on the mushroom species. As a result of adding various amino acids to the mycelial culture medium, methionine (Met) was shown to be the most effective additive. The most preferable condition of the additive was the combination of 4 mM Met and 1 g/l of yeast extract, and the maximum ERG production reached approximately 1.7 mg/l, which corresponds to 2.4 times (0.7 mg/l) that in the basal medium without Met. Although the supplementation of Met enhanced the ERG production, the mycelial growth was significantly inhibited. Furthermore, the analysis of amino acids in the culture medium revealed that the Met additive reduced the consumption rates of most amino acids tested, probably due to the decrease in mycelial growth. Taking these results into consideration, we suggest that the addition of Met to the mycelial culture medium is an efficient way to enhance the ERG production in economically important mushroom species.     

Utilization of methyloleate in production of microbial lipase

In this article, we report the development and optimization of an industrial culture medium for the production of extracellular lipase in the yeast Yarrowia lipolytica. Until now olive oil in combination with glucose was used as the carbon source and inducer for the production of lipase. Our results demonstrate that methyloleate, a cheap hydrophobic compound, could efficiently substitute olive oil as the inducer and carbon source for lipase production. A new process of lipase production was developed yielding a twofold increase in the level of production compared with the levels in previous reports.     

Macrophage-stimulating activity of exo-biopolymer from cultured rice bran with <Emphasis Type="Italic">Monascus pilosus</Emphasis>

To find a new use of rice bran, five fungi were examined for the production of exo-biopolymer with macrophage-stimulating activity from rice bran. Among the exo-biopolymers produced from the cultures, Monascus pilosus had the most potent macrophage stimulating activity in a liquid culture rather than in a solid culture. In order to improve the yield of exo-biopolymer with macrophage-stimulating activity, a suitable medium for exo-biopolymer was tested in submerged culture of M. pilosus. The highest amount of exo-biopolymer (13.9 mg/mL) was obtained in a medium containing rice bran as an only carbon source followed by media with additional maltose and sucrose (13.8 and 13.7 mg/mL, respectively). The addition of peptone resulted in the production of high amount of exo-biopolymer (15.1 mg/mL), meanwhile the addition of ammonium chloride resulted in 264.0 μg/mL of glucosamine content. Among eight different kinds of inorganic salts tested, potassium phosphate (0.1%) was the most effective inorganic salt for the mycelial growth and exo-biopolymer production. Therefore the optimal medium composition was as follows (g/L): 20 g of rice bran, 5 g of peptone, and 1 g of KH₂PO₄. The optimal culture pH and time for mycelial growth and exo-biopolymer production was pH 5.0 and 25°C, respectively. The maximum exo-biopolymer (20.1 mg/mL) was observed at the fourth day of cultivation. Exo-biopolymer, a crude polysaccharide fraction, mainly contained neutral sugar (81.8%) with considerable amounts of uronic acid (18.2%). Component sugar analysis showed that the active fraction consisted mainly of arabinose, galactose, glucose, which was digested from starch of rice bran during cultivation, and uronic acid (molar ratio; 0.8:1.0:0.7:0.8).     

Biosynthesis of Unsaturated Fatty Acids via Mortierella Isabellina Cultivated in a Medium Containing Butanol

IntroductionThe biosynthesis of unsaturated fatty acidshasattracted more attention in recent years. Forexample,linoleic and linolenic acids are importantmaterials for pharmaceutical and food industries.Besides,they can be used to synthesize paint,printing ink and surfactant,etc. A number ofmicroorganisms have been studied as potentialcommercial sources to produce unsaturated fattyacids[1] .Agricultural and industrial products,by-products,etc. have been employed in thecultivation of those orga…     

Fungal morphology in submerged cultures and its relation to glucose oxidase excretion by recombinant Aspergillus niger

The effect of culture conditions such as medium composition and shear stress on the fungal pellet morphology in shake-flask cultures and its relation to glucose oxidase (GOD) excretion by recombinant Aspergillus niger NRRL 3 (GOD 3–18) was investigated. It was shown that culture conditions resulting in the formation of smaller fungal pellets with an increased mycelial density result in higher yields of exocellular GOD. The pellets obtained in shake-flask cultures showed distinct layers of mycelial density with only the thin outer layer consisting of a dense mycelial network. The performance of the recombinant strain and the process of pellet formation was also analyzed during batch cultivation in a stirred-tank bioreactor. It was shown that the process of pellet formation occurred in two steps: (1) aggregation of free spores to spore clusters with subsequent germination and formation of small aggregates surrounded by a loose hyphal network, and (2) aggregation of the primary aggregates to the final full-size pellets. The fungal pellets formed during bioreactor cultivation were smaller, did not show large differences in mycelial density, and were more efficient with respect to the production of exocellular GOD. The decreasing pellet size also correlated with an increased mycelial density, indicating an improvement of the transport of nutrients to the inner parts of the pellet.     

Regulation of dome formation in differentiated epithelial cell cultures.

Rat mammary (Rama 25) and dog kidney (MDCK) epithelial cell cultures formed 'domes' of cells due to fluid accumulation in focal regions between the culture dish and the cell monolayer. Addition of ouabain caused collapse of domes, suggesting that transport functions were required for maintenance of domes. Dome formation in both epithelial cell lines was stimulated by a broad spectrum of known inducers of erythroid differentiation in Fried erythroleukemia cells. Among these inducers were: 1) polar solvents such as dimethyl-sulfoxide, dimethylformamide, and hexamethylene bisacetamide; 2) purines such as hypoxanthine, inosine, and adenosine; 3) low-molecular-weight fatty acids such as n-butyrate; and 4) conditions expected to elevate levels of cyclic AMP. In the latter group were activators of adenylate cyclase such as cholera toxin and prostaglandin E 1; cyclic AMP phosphodiesterase inhibitors such as theophylline and 1-methyl-3-isobutylxanthine; and analogs of cyclic AMP. Induction of domes occurred 15--30 h after addition of inducer to the culture medium. Induction by chemicals was serum-dependent and required protein synthesis but not DNA synthesis. Induced dome formation was reversible after removal of inducer, requiring the continuous presence of inducer. Reversal was also observed after either either removal of serum or addition of inhibitors of protein synthesis. These results suggest that hypothesis that domes arise in these epithelial cultures by a process that is similar to cell differentiation and is influenced by cyclic AMP.     

Conditions that promote production of lactic acid byZymomonas mobilis in batch and continuous culture

This study documents the similar pH-dependent shift in pyruvate metabolism exhibited byZymomonas mobilis ATCC 29191 and ATCC 39676 in response to controlled changes in their steady-state growth environment. The usual high degree of ethanol selectivity associated with glucose fermentation by Z.mobilis is associated with conditions that promote rapid and robust growth, with about 95% of the substrate (5% w/v glucose) being converted to ethanol and CO₂, and the remaining 5% being used for the synthesis of cell mass. Conditions that promote energetic uncoupling cause the conversion efficiency to increase to 98% as a result of the reduction in growth yield (cell mass production). Under conditions of glucose-limited growth in a chemostat, with the pH controlled at 6.0, the conversion efficiency was observed to decrease from 95% at a specific growth rate of 0.2/h to only 80% at 0.042/h. The decrease in ethanol yield was solely attributable to the pH-dependent shift in pyruvate metabolism, resulting in the production of lactic acid as a fermentation byproduct. At a dilution rate (D) of 0.042/h, decreasing from pH 6.0 to 5.5 resulted in a decrease in lactic acid from 10.8 to 7.5 g/L. Lactic acid synthesis depended on the presence of yeast extract (YE) or tryptone in the 5% (w/v) glucose-mineral salts medium. At D = 0.15/h, reduction in the level of YE from 3 to 1 g/L caused a threefold decrease in the steady-state concentration of lactic acid at pH 6. No lactic acid was produced with the same mineral salts medium, with ammonium chloride as the sole source of assimilable nitrogen. With the defined salts medium, the conversion efficiency was 98% of theoretical maximum. When chemostat cultures were used as seed for pH-stat batch fermentations, the amount of lactic acid produced correlated well with the activity of the chemostat culture; however, the mechanism of this prolonged induction     

Effects of polysaccharide elicitors from endophytic Fusarium oxysporium Dzf17 on growth and diosgenin production in cell suspension culture of Dioscorea zingiberensis

Three polysaccharides, namely exopolysaccharide (EPS), water-extracted mycelial polysaccharide (WPS) and sodium hydroxide-extracted mycelial polysaccharide (SPS), were prepared from the endophytic fungus Fusarium oxysporium Dzf17 isolated from the rhizomes of Dioscorea zingiberensis. The effects of the time of addition and polysaccharide concentration on the growth and diosgenin accumulation in cell suspension culture of D. zingiberensis were studied. Among them, WPS was found to be the most effective polysaccharide. When WPS was added to the medium at 20 mg/L on the 25th day of culture, the cell dry weight was increased 1.34-fold, diosgenin content 2.85-fold, and diosgenin yield 3.83-fold in comparison to those of control. EPS and SPS showed moderate and relatively weak enhancement effects on cell growth and diosgenin accumulation, respectively. The dynamics of cell growth and diosgenin accumulation when WPS was added to the medium at 20 mg/L on the 25th day of culture were investigated, and results showed that dry weight of cells reached a maximum value on day 30 but the maximum diosgenin content was achieved on day 31.     

Metal induced photoluminescence quenching of a phenylene vinylene oligomer and its recovery

Metal/polymer interfaces play an important role in polymeric light emitting diodes (LEDs). In typical organic light-emitting devices, metallic electrodes are used to inject charged carriers into the organic electroluminescent (EL) medium. However, what other effects the metals have on the organic medium is not well known. In this work, we report severe photoluminescence (PL) quenching of organic thin films comprising of one of the most useful materials, namely 1,4-bis[4-(3,5-di-tert-butylstyryl)styryl]benzene (4PV), upon sub-monolayer deposition of Al, Ag, and Ca in an ultra high vacuum environment. The severity of the luminescence quenching may greatly affect the EL device performance. Gap states at the Ca/4PV interface are shown to be responsible for the PL quenching. The oxidation of Ca resulted in the removal of the gap states and the recovery of the quenched PL.     

Luteapyrone,a Novel ƴ-Pyrone Isolated from the Filamentous Fungus Metapochonia lutea

In the process of screening for new bioactive microbial metabolites we found a novel ƴ-pyrone derivative for which we propose the trivial name luteapyrone, in a recently described microscopic filamentous fungus, Metapochonia lutea BiMM-F96/DF4. The compound was isolated from the culture extract of the fungus grown on modified yeast extract sucrose medium by means of flash chromatography followed by preparative HPLC. The chemical structure was elucidated by NMR and LC-MS. The new compound was found to be non-cytotoxic against three mammalian cell lines (HEK 263, KB-3.1 and Caco-2). Similarly, no antimicrobial activity was observed in tested microorganisms (gram positive and negative bacteria, yeast and fungi).     

二咔唑四苯乙烯多功能发光化合物的合成与性能

合成了一种新型的具有压致荧光变色效应的聚集诱导增强发光(PAIE)化合物二咔唑四苯乙烯; 通过核磁共振、质谱和元素分析等手段对其进行了结构表征; 利用紫外吸收光谱、荧光发射光谱、热分析和X射线衍射等手段研究了化合物的基本性能. 实验结果表明, 随着水含量的增加, 该化合物溶液荧光强度增强了171倍, 荧光量子产率提高了100倍, 表现出明显的聚集诱导增强发光效应; 在外界因素作用下该化合物固体样品可实现结晶态与无定形态的相互转变. 结晶态的荧光发射波长为450 nm, 无定形态为480 nm, 相差30 nm, 说明该化合物具有明显的压致荧光变色效应; 将该化合物用于制备发光器件, 未经优化的器件亮度达2438 cd/m², 电流效率为2.87 cd/A, 流明效率为1.81 lm/W. 该化合物是一种多功能材料.     

Preferential utilization of glucose over melibiose, and vice versa, in a pts mutant of Salmonella typhimurium.

Preferential utilization of glucose and melibiose was investigated in wild type cells and in pts mutant (ptsI-leaky) cells of Salmonella typhimurium. A typical diauxic growth and preferential utilization of glucose over melibiose were observed in wild type cells when these two sugars were added as carbon source. Similar results were obtained with a pts mutant (SB1476) although utilization of glucose was slow. When cyclic adenosine 3',5'-monophosphate (cAMP) was added to the culture medium to release the catabolite repression, preferential utilization of glucose was still observed in wild type cells. With glucose-induced mutant cells, preferential utilization of glucose was observed in the presence of cAMP. Gradual utilization of melibiose took place when glucose concentration in the medium decreased. Surprisingly, preferential utilization of melibiose over glucose was observed with melibiose-induced and glucose-uninduced mutant cells in the presence of cAMP.     

Cloning and expression of two genes coding endo-β-1,4-glucanases from <Emphasis Type="Italic">Trichoderma asperellum</Emphasis> PQ34 in <Emphasis Type="Italic">Pichia pastoris</Emphasis>

Two genes coding endo-β-1,4-glucanases were cloned from Trichoderma asperellum PQ34 which was isolated from Thua Thien Hue province, Vietnam. The expression of these genes in Pichia pastoris produced two enzymes with molecular masses of approximately 46 kDa (about 42 kDa of enzymes and 4 kDa of signal peptide). The effects of induction time and temperature, inducer concentration, and culture medium on the endo-β-1,4-glucanase activity were investigated. The results showed that the highest total activities of two endo-β-1,4-glucanases were approximately 4.7 × 10^?8 kat (from Glu1-TA gene) and 7.3 × 10^?8 kat (from Glu2-TA gene) occurred after 4 days of induction using 25 mL L^?1 methanol at 30?C when the yeast cells were cultured in a YPL medium.     

A Sphingosine-type cerebroside in Clavicorona pyxidata induce fruit body formation

Clavicorona pyxidata is a wild edible and medicinal mushroom that is rich in bioactive natural products and has thus been extensively used as traditional medicine in China. The present study has determined that the organic crude extract prepared from a fermented culture of C. pyxidata imparted auto-inhibitory effects on mycelial growth and then induced the formation of fruiting bodies. By monitoring bioactivity, one compound was isolated via successive chromatography over silica gel, Sephadex LH-20, and Cl8-reversed phase silica gel and was identified as a known sphingosine-type cerebroside by nuclear magnetic resonance (NMR) and physicochemical data, namely, (4E, 8E)-N-D-2′-hydroxypalmitoyl-1-O-β-D-glucopyranosyl-9-methyl-4,8-sphingadienine. The application of this cerebroside at a concentration of 200 μg/disc paper resulted in the inhibition of aerial hyphal growth of C. pyxidata. The findings of the present study indicated that this C. pyxidata cerebroside is a fruiting body-inducing substance (FIS).     

Application of sucrose fatty acid ester to reverse micellar extraction of lysozyme

Reverse micellar extraction of lysozyme has been carried out using an organic solution containing a mixture of monoester and polyester of sucrose fatty acid ester. The forward extraction of lysozyme from the feed aqueous phase to the reverse micellar organic phase of the mixture of monoester and polyester of sucrose fatty acid ester at pH 7.2 was strongly dependent upon the weight fraction of monoester, while any amount of lysozyme was not extracted only by using monoester or polyester. The forward extraction ratio dramatically increased with an increase in the concentration of fatty acid ester, and was high around neutral pH and at low ionic strength. The backward extraction of lysozyme from the reverse micellar organic phase to the recovery aqueous phase exhibited high efficiency at acidic pH value or at high ionic strength. The addition of sucrose into the recovery aqueous phase promoted the backward extraction ratio, and caused the activity of lysozyme recovered from the reverse micellar phase to be retained perfectly.     

多孔硅镶嵌正丁胺/激光染料复合膜的荧光谱

多孔介质染料镶嵌膜有可能是发展固体染料激光器的一种途径[1].由于其所具有的微孔结构和大的比表面积,故使其成为激光染料理想的载体,以形成多孔硅基发光材料[2].　　我们用正丁胺作碳源,采用射频辉光(ＲＦ)放电法制备碳膜.利用正丁胺、Ｒ6Ｇ/聚乙二醇分别作碳源和蒸发源得到一种混合膜,如将其沉积在刚制备的新鲜多孔硅上则得到多孔硅镶嵌复合膜.本文着重研究了镶嵌于多孔硅中的正丁胺/Ｒ6Ｇ的荧光光谱,并考察了多孔硅衬底的改变对多孔硅镶嵌膜发光的影响.1　样品制备　　(1)多孔硅的制备　制备多孔硅(ＰＳ)所用的材料为(100)晶向的ｐ型单…     

多孔硅镶嵌正丁胺/激光染料复合膜的荧光谱

The photoluminescence (PL) of the compound films made by implanting n-butylamine/ Rhodamine into the porous silicon films was studied. Comparison and discussion of the difference of PL of the compound films and the dyes were carried out. The PL of the compound films with different substrates was measured.     

Growth of kidney epithelial cells in hormone-supplemented, serum-free medium.

Madin Darby canine kidney cells can grow in synthetic medium supplemented with 5 factors--insulin, transferrin, prostaglandin E1, hydrocortisone and triiodothyronine--as a serum substitute. These 5 factors permit growth for one month in the absence of serum, and a growth rate equivalent to that observed in serum-supplemented medium. Dibutyryl cAMP substitutes for prostaglandin E1 in the medium, suggesting that increased growth of Maden Darby canine kidney cells results from increased intracellular cAMP. Potential applications of the serum-free medium are discussed. The medium permits the selective growth of primary epithelial cell cultures in teh absence of fibroblast overgrowth, and a defined analysis of the mechanisms by which hormones regulate hemicyst formation.