均匀设计法优化灰树花深层培养基配方

系统研究了碳源、氮源、无机盐、维生素等培养基因素对灰树花深层发酵菌丝体产量的影响 ,并通过均匀设计法优化了发酵培养基配方。结果表明 :4 6 %玉米粉、3 5 %豆饼粉、0 1%葡萄糖、0 32 %KH2 PO4 、0 0 1%MgSO4 、少量VB1的培养基配方可使菌丝体产量达到最大。采用此配方试验 ,菌丝体产量平均值达 1 77± 0 0 6g/10 0mL。     

Modeling Grifola frondosa fungal growth during solid‐state fermentation

Grifola frondosa (maitake) is an edible and medicinal mushroom. Considering its increasing popularity, there are limited references for its cultivation. Previous studies demonstrated that carpophore formation is correlated directly with mycelial biomass. The development of a mathematical model for its growth under solid‐state fermentation (SSF) may help to predict the potential of different substrates for maitake production. G. frondosa growth and basidiome development was studied, using oak sawdust and corn bran as substrates. The fungal biomass content was determined by measuring N‐acetyl‐D ‐glucosamine (NAGA). It increased steadily for the first 80 days, to a maximum in coincidence with the first fruiting (60.5 μg NAGA/mg dry sample). Two mathematical models were selected to evaluate G. frondosa development, measuring reducing sugars consumption and NAGA synthesis, as an indirect assessment of fungal growth. Both models showed a good fit between predicted and experimental data: logistic model (R²=0.8896), two‐stage model (R²=0.8878), but the logistic model required a minor number of adjustment parameters.     

灰树花多糖的提取及抗氧化活性

采用单因素和正交试验法对热水浸提、超声波辅助和微波辅助提取灰树花多糖的工艺进行研究,分别获得了3种方法的最佳条件,并发现微波辅助法最佳,其最优条件为:微波功率800 W、微波时间3 min,浸提2h,多糖得率为13.05％,比热水浸提法提高了51.22％.利用提取的灰树花多糖进行抗氧化性研究,发现灰树花多糖对O2-·和·OH都具有一定的清除作用,且多糖浓度与其对O2-·的清除作用存在量效关系,但不如·OH明显.     

Grifolisin, a member of the sedolisin family produced by the fungus Grifola frondosa

The pepstatin-insensitive carboxyl proteinase grifolisin was purified from fruiting bodies of the fungus Grifola frondosa, a maitake mushroom. The enzyme had an optimum pH of 3.0 for the digestion of hemoglobin and 2.8 for milk casein digestion. Its molecular mass was determined to be 43kDa by SDS-PAGE and 40kDa by gel chromatography on Superose 12, and its isoelectric point was found to be 4.6 by isoelectric focusing. The enzyme hydrolyzed four major bonds in the oxidized insulin B-chain: Phe1-Val2, Ala14-Leu15, Gly20-Glu21 and Phe24-Phe25 at pH 3.0. The first 15 amino acid residues in the N-terminal region were AVPSSCASTITPACL, and the coding region of the grifolisin gene (gfrF) has a 1960-base pair cDNA. The predicted mature grifolisin protein consisted of 365 residues and was 26% identical to that of sedolisin from Pseudomonas sp. 101 and 34% identical to that of aorsin from Aspergillus oryzae. Grifolisin is a member of the sedolisin S53 family and is not inhibited by pepstatin.     

Extracellular laccase produced by an edible basidiomycetous mushroom, Grifola frondosa: purification and characterization

A major laccase isozyme (Lac 1) was isolated from the culture fluid of an edible basidiomycetous mushroom, Grifola frondosa. Lac 1 was revealed to be a monomeric protein with a molecular mass of 71 kDa. The N-terminal amino acid sequence of Lac 1 was highly similar to those of laccases of some other white-rot basidiomycetes. Lac 1 showed the typical absorption spectrum of a copper-containing enzyme. The enzyme was stable in a wide pH range (4.0 to 10.0), and lost no activity up to 60 °C for 60 min. The optimal pH of the enzyme activity varied among substrates. The K(m) values of Lac 1 toward 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), 2,6-dimethoxyphenol, guaiacol, catechol, and 3,4-dihydroxy-L-phenylalanine were 0.0137 mM, 0.608 mM, 0.531 mM, 2.51 mM, and 0.149 mM respectively. Lac 1 activity was remarkably inhibited by the chloride ion, in a reversible manner. Lac 1 activity was also inhibited by thiol compounds.     

灰树花孔菌超微粉体内抗肿瘤作用研究

通过研究肿瘤抑制率、脏器指数、肿瘤切片的观察以及血清中影响因子干扰素-γ（IFN-γ）、白细胞介素-2（IL-2）、血管内皮细胞生长因子（VEGF）、过氧化氢酶（CAT）、谷胱甘肽-过氧化物酶（GSH-PX）和超氧化物歧化酶（SOD）等指标的变化对比分析灰树花孔菌 Grifola frondosa子实体粗粉及灰树花孔菌子实体超微粉对Hep-A-22荷瘤小鼠体内抗肿瘤和免疫调节作用。结果表明,各剂量组分均具有抑制肿瘤生长作用,其中灰树花孔菌超微粉高剂量组（1 500mg/kg）抑瘤效果最佳,与模型组比较有极显著性差异（ P<0.01）。通过HE染色后的肿瘤细胞可观察到坏死面积增大,同时该组血清中IFN-γ、IL-2、VEGF、GSH-PX和SOD含量显著增加（ P<0.01或 P<0.05）,并与抑制肿瘤具有一定相关性。     

基于UPLC-QTOF-MS代谢组学研究灰树花发酵的代谢差异

为了解天麻苦荞复配液的添加对灰树花深层发酵过程中代谢产物的差异性,采用超高效液相色谱-四级杆串联飞行时间质谱（UPLC-QTOF-MS）技术结合多变量统计分析方法,对发酵7d的灰树花菌丝体细胞代谢物进行分析。主成分（PCA）模型显示添加天麻苦荞复配液的菌丝体细胞与对照组菌丝体细胞相比代谢产物差异明显（P<0.05）,通过正交偏最小二乘判别分析（OPLS-DA）,以VIP（varible importance in the projection）>1和P<0.05为条件进行筛选和鉴定得到44种差异代谢物,包括糖类6种、氨基酸类13种、维生素类5种、核苷酸类7种、有机酸类10种、脂肪酸类3种。其中,与对照组相比鼠李糖、D-半乳糖、D-甘露醇、果糖-6-磷酸等7种物质含量显著下调,D-木糖醇、异亮氨酸、赖氨酸、泛酸、二十二碳六烯酸、D-葡萄糖醛酸、琥珀酸等37种物质含量显著上调。通过对差异代谢物进行通路分析,得到具有显著影响的代谢通路14条,推测了灰树花胞外多糖合成通路。由此推断天麻苦荞复配液的添加对灰树花胞外多糖的增效作用和提升营养品质的原因,为今后深层次研究外源添加物对灰树花发酵过程的影响提供理论依据。     

Production and properties of three pectinolytic activities produced byAspergillus niger in submerged and solid-state fermentation

Three extracellular pectinases were produced byAspergillus niger CH4 by submerged and solid-state fermentation, and their physicochemical and kinetic properties were studied. The highest productivities of endo- and exo-pectinase and pectin lyase were obtained with solid-state fermentation. The kinetic and physicochemical properties of these enzymes were influenced by the type of culture method used. All activities were very different in terms of pH and temperature optima, stability at different pH and temperature values and affinity for the substrate (K _m values). In solid-state fermentation, all pectinase activities were more stable at extreme pH and temperature values but theK _m values of endo-pectinase and pectin lyase were higher with respect to those activities obtained by the submerged-culture technique. The pectin lyase activity obtained by the submerged-culture technique showed substrate inhibition but the enzyme obtained by solid-state fermentation did not. Electrophoresis, using sodium dodecyl sulphate/polyacrylamide gel with enzymatic extracts obtained for both culture methods, showed the same number on protein bands but some differences were found in their electrophoretic position. The results obtained in this work suggest that the culture method (submerged or solid-state) may be responsible for inducing changes in some of the pectinolytic enzymes produced byA. niger.     

Measurement of α-amylase and glucoamylase activities produced during fermentation

A method for the automatic measurement of α-amylase and glucoamylase activities during fermentation has been developed. Soluble starch dyed with Remazol Brilliant Orange was used as the substrate for α-amylase and 4-nitrophenyl α-d-glucopyranoside for glucoamylase. The same automatic analysis system could be used for both of these enzymes because the reaction products were measured at the same wavelength. Simultaneous pick-up of enzyme and the respective substrate was enabled by using two samplers. The presence of α-amylase did not interfere with the glucoamylase determination. Absolute values for α-amylase activity were obtained using a mathematical correction. Monitoring of these enzymes was accomplished during microbial fermentation.     

Physical characteristics and antioxidant effect of polysaccharides extracted by boiling water and enzymolysis from Grifola frondosa

Grifola frondosa has been widely consumed in China and other Asian countries. Recent studies on G. frondosa have focused on the activities of polysaccharides extracted by water, and the activities of polysaccharides extracted by enzymolysis have not been studied. In this work, the relationship between the physical properties and antioxidant activity of polysaccharides extracted from G. frondosa by boiling water and enzymolysis was studied. Five polysaccharide extracts from the fruit body of G. frondosa were prepared by different extracting methods including boiling water, single enzyme enzymolysis with three different single enzymes (cellulose, pectinase, and pancreatin), and combined enzyme enzymolysis (cellulose:pectinase:pancreatin; 2:2:1). Characteristics such as the viscosity, Mw, polysaccharide content, protein content, infrared spectra, and antioxidant activities of the extracts were evaluated. The highest antioxidant activity was exhibited by the extracts prepared by combined enzyme extraction. The correlation analysis between antioxidant activity and polysaccharide content, protein content, Mw or viscosity indicated that the Mw had a more important role in antioxidant activity. Overall, the results indicate that the combined enzyme polysaccharide extracts can be developed as a new potential natural antioxidant.     

Preparation of a chemically sulfated polysaccharide derived from Grifola frondosa and its potential biological activities

This report describes the preparation, characterization and potential biological activities of a chemically sulfated polysaccharide (S-GAP-P), which was derived from water-insoluble polysaccharide of Grifola frondosa mycelia. S-GAP-P was determined to be a glucan sulfate with the average molecular weight of 28 kDa and the sulfur content of 16.4%. The antitumor and immunomodulating activities of the sulfated derivative were estimated in vitro and in vivo. S-GAP-P inhibited the proliferation of SGC-7901 cells and induced apoptosis, in a dose-dependent manner. And the results from in vivo experiments demonstrated that S-GAP-P significantly inhibited the tumor growth and enhanced the peritoneal macrophages phagocytosis in S180-bearing mice. It is noteworthy that S-GAP-P could accelerate the antitumor activity of CTX and improve the immunocompetence damaged by CTX, suggesting the combination might increase cytotoxic efficacy and decrease toxicity of some chemotherapeutic agents in cancer treatment.     

灰树花多糖对乳腺癌细胞MCF-7的凋亡作用

采用MTT法测定不同给药浓度的灰树花多糖(PGF) (1、10、20、50、100和200 μg/mL)在24、48和72 h对乳腺癌细胞(MCF-7)增殖的抑制率,并采用Hoechst染色与流式细胞技术观察20、50和100 μg/mL PGF给药24 h后MCF-7的凋亡情况,同时采用Western blotting对20、50、100 μg/mL PGF给药24 h后MCF-7细胞中Bax、Bcl-2、Pro-Caspase-3以及Cleaved Caspase-3的蛋白表达水平进行检测。研究发现PGF给药24、48和72 h后对MCF-7的增殖均有显著的抑制作用。随着PGF给药浓度增加,MCF-7细胞核裂解增多,细胞凋亡数量增多。PGF 20、50和100 μg/mL给药对MCF-7细胞Bax、Bcl-2、Pro-Caspase-3以及Cleaved Caspase-3的蛋白表达水平可见显著性差异。     

灰树花胞外多糖的结构及免疫调节活性

对灰树花胞外多糖A组分(EXGFP-A)进行结构分析和免疫活性的研究。结构分析结果表明,EXGFP-A是一种主要含有葡萄糖的吡喃型中性多糖。气相结果说明EXGFP-A的单糖组成为鼠李糖、阿拉伯糖、木糖、甘露糖、葡萄糖、半乳糖,摩尔比为0.28∶0.31∶0.30∶0.06∶7.98∶0.61。MTT(3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazo-lium bromide)比色实验表明,当EXGFP-A浓度为80μg/m L,作用48 h时,RAW264.7细胞增殖指数达到最大值,为137.5%。吖啶橙(AO)染色结果表明EXGFP-A能够激活RAW264.7细胞,增强细胞内部核酸代谢水平。EXGFP-A在一定浓度范围内,可以提高RAW264.7细胞中NO的释放量,上调细胞内TNF-α、IL-1β、IL-6、IL-12、IFN-γ细胞因子以及细胞中iNOS的mRNA水平的表达。结果表明,EXGFP-A具有一定的免疫调节活性,为灰树花胞外多糖的结构分析和应用提供了科学依据。     

不同营养基质与条件对灰树花生长的影响

探讨了不同营养基质与条件对灰树花[Grifola frondosa(Fr.)S.F.Gray]生长的影响。试验结果表明：菌丝生长的最适pH为5-6;最适氮源为蛋白胨、牛肉膏和谷氨酰胺,葡萄糖和蛋白胨最适浓度分别为100和1g/L;菌丝在黑暗环境下生长良好;使用马铃薯蛋白胨培养基进行振荡培养,菌丝球生长较好;母种采用马铃薯麦麸培养基,栽培种选用棉子壳麦麸石培养料,可缩短制种周期,获得质量较高的菌种;菌丝含有较多的钙、铁和锌等元素。     

Exopectinases produced by Aspergillus niger in solid-state and submerged fermentation: a comparative study

Exopectinase production by Aspergillus niger was compared in submerged fermentation (SmF) and solid-state fermentation (SSF). SSF was carried out using polyurethane foam (PUF) as the solid support. The purpose was to study the effect of sucrose addition (0 or 40 g/l) and water activity level (A _w=0.99 or 0.96) on the level of enzyme activity induced by 15 g/l of pectin. Mycelial growth, as well as extracellular protease production, was also monitored. Sucrose addition in SmF resulted in catabolite repression of exopectinase activity. However, in SSF, an enhancement of enzyme activity was observed. Protease levels were minimal in SSF experiments with sucrose and maximal in SmF without sucrose. Exopectinase yields (IU/g X) were negligible in SmF with sucrose. The high levels of exopectinase with sucrose and high A _w in SSF can be explained by a much higher level of biomass production without catabolite repression and with lower protease contamination. Journal of Industrial Microbiology & Biotechnology (2001) 26, 271–275. Received 05 July 2000/ Accepted in revised form 27 January 2001     

Purification and characterization of polygalacturonase produced by thermophilic Thermoascus aurantiacus CBMAI-756 in submerged fermentation

An extracellular polygalacturonase was isolated from 5-day culture filtrates of Thermoascus aurantiacus CBMAI-756 and purified by gel filtration and ion-exchange chromatography. The enzyme was maximally active at pH 5.5 and 60–65°C. The apparent K _m with citrus pectin was 1.46 mg/ml and the V _max was 2433.3 μmol/min/mg. The apparent molecular weight of the enzyme was 30 kDa. The enzyme was 100% stable at 50°C for 1 h and showed a half-life of 10 min at 60°C. Polygalacturonase was stable at pH 5.0–5.5 and maintained 33% of initial activity at pH 9.0. Metal ions, such as Zn⁺², Mn⁺², and Hg⁺², inhibited 50, 75 and 100% of enzyme activity. The purified polygalacturonase was shown to be an endo/exo-enzyme, releasing mono, di and tri-galacturonic acids within 10 min of hydrolysis.     

Isolation and characterization of a lectin from Grifola frondosa fruiting bodies

An N-acetylgalactosamine-specific lectin (GFL) was isolated from Grifola frondosa fruiting bodies by affinity chromatographies on acid-treated Sepharose CL-4B and then GalNAc-Toyopearl. The isolated lectin agglutinated all types of erythrocytes equally. Molecular masses estimated by gel filtration under various buffers and matrices varied from 30 to 52 kDa. On the other hand, SDS-PAGE in the presence or absence of 2-mercaptoethanol showed three major bands of 33, 66 and 100 kDa and a faint band of 65 kDa. This lectin exhibited GalNAc-specificity. The protein was a glycoprotein containing 3.3% total sugar, and the amino acid analysis revealed a high content of acidic and hydroxy amino acids and a low content of methionine and histidine. GFL was cytotoxic against HeLa cells. The toxicity did not appear after preincubating the lectin with the haptenic sugar N-acetylgalactosamine.     

灰树花多糖的分子修饰及其活性研究进展

灰树花是一种高蛋白低脂肪的食品,具有免疫调节、抗氧化和抗肿瘤等生物活性。其中,多糖是灰树花的主要活性成分之一。对多糖进行分子修饰是提高它原有的生物活性或增加新活性的重要途径之一。综述了灰树花多糖的分子修饰方法,以及修饰后灰树花多糖的生物活性及其构效关系的研究进展,以期为灰树花多糖的深入研究和开发利用提供参考。     

猴头菌高产麦角甾醇液体发酵工艺优化

以菌丝体中麦角甾醇产量为考察指标,在单因素实验的基础上用响应面分析法考察碳源、氮源和无机盐3个因素对麦角甾醇发酵产量的影响,以获得猴头菌液体发酵产麦角甾醇最优工艺,建立高产、稳定的猴头菌液体发酵产麦角甾醇生产工艺.经响应面分析,各因素按照对响应值的影响顺序为:氮源＞碳源＞无机盐,且氮源对麦角甾醇产量的影响极显著,碳源和...     

灰树花菌株的复壮及常压室温等离子体诱变

【背景】实验室所用灰树花菌株系长期继代培养,易出现菌株退化。【目的】通过菌株复壮的方法实现菌株的生物学活性及性状的恢复,并借助高效诱变仪对菌株实施诱变,以期得到活性更高、遗传稳定的诱变株。【方法】分别以PDA加富培养基和PDA-板栗壳培养基为培养基质,采用尖端菌丝分离法进行菌株复壮,得到回复菌株原有的生物学活性及性状的复壮株P-2,为了进一步提高菌株的高产性能,利用常压室温等离子体(atmosphericroomtemperatureplasma,ARTP)诱变技术作用于复壮株P-2菌丝体,最终筛选到一株性能优良、遗传稳定性高的诱变株b-35。【结果】复壮后的菌株P-2菌丝干重和多糖含量分别达到1.18%和19.01%,较出发株分别提高35.17%和35.11%,通过发酵罐验证菌株的发酵周期由48h缩短至32h,菌株发酵活性及效率明显提高。诱变株b-35菌丝干重和多糖含量分别达到1.56%和25.07%,较复壮株P-2分别提高了40.15%和39.33%。【结论】ARTP诱变方法易操作、无污染且诱变效率高,是获得灰树花高产菌株的重要方式。