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建立1-苯基-3-甲基-5-吡唑啉酮(PMP)柱前衍生HPLC法测定虫草多糖中单糖组分的通用性方法。本试验以9种单糖标准品为研究对象,通过单因素和响应面试验对衍生反应的温度、时间、pH和PMP用量进行了优化,并运用改进的方法测定了3批不同产地的蛹虫草多糖的单糖组分。结果表明:PMP与单糖摩尔比12:1、温度80℃、时间60min、 pH 8.2为最佳衍生条件,方法学验证证明该方法稳定、可靠、重现性良好。3批蛹虫草多糖中均稳定检测到甘露糖、半乳糖醛酸、葡萄糖、半乳糖和阿拉伯糖,摩尔比约为3.8:1.6:5.4:5.8:1,研究结果可为改善虫草多糖成分分析和构效关系研究提供支持。 相似文献
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Rongmin Yu Wei Yang Liyan Song Chunyan Yan Zhang Zhang Yu Zhao 《Carbohydrate polymers》2007,70(4):430-436
The water-soluble crude polysaccharides were obtained from the fruiting bodies of cultured Cordyceps militaris by hot water extraction followed by ethanol precipitation. The polysaccharides were successively purified by chromatography on DEAE–cellulose-52 and Sephacryl S-100 HR columns, giving main three polysaccharide fractions termed P50-1, P70-1, and P70-2. Structural features of P70-1 were investigated by a combination of chemical and instrumental analysis, such as partial acid hydrolysis, methylation analysis, periodate oxidation – Smith degradation, GC–MS, 13C NMR, HPAEC-PAD, and FT-IR. The results indicated that P70-1 has a backbone of (1 → 6)-linked β-d-mannopyranosyl residues, which occasionally branches at O-3. The branches were mainly composed of (1 → 4)-linked -d-glucopyranosyl and (1 → 6)-linked β-d-galactopyranosyl residues, and terminated with β-d-galactopyranosyl residues and -d-glucopyranosyl residues. In the in vitro antioxidant assay, P70-1 was found to possess hydroxyl radical-scavenging activity with an IC50 value of 0.548 mg/ml. 相似文献
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Aly AH Edrada-Ebel R Wray V Müller WE Kozytska S Hentschel U Proksch P Ebel R 《Phytochemistry》2008,69(8):1716-1725
Extracts of cultures grown in liquid or on solid rice media of the fungal endophyte Ampelomyces sp. isolated from the medicinal plant Urospermum picroides exhibited considerable cytotoxic activity when tested in vitro against L5178Y cells. Chromatographic separation yielded 14 natural products that were unequivocally identified based on their 1H and 13C NMR as well as mass spectra and comparison with previously published data. Six compounds (2, 4, 5, 7, 9 and 11) were natural products. Both fungal extracts differed considerably in their secondary metabolites. The extract obtained from liquid cultures afforded a pyrone (2) and sulfated anthraquinones (7 and 9) along with the known compounds 1, 3, 6 and 8. When grown on solid rice medium the fungus yielded three compounds 4, 5 and 11 in addition to several known metabolites including 6, 8, 10, 12, 13 and 14. Compounds 4, 8 and 10 showed the strongest cytotoxic activity against L5178Y cells with EC50 values ranging from 0.2–7.3 μg/ml. Furthermore, 8 and 10 displayed antimicrobial activity against the Gram-positive pathogens, Staphylococcus aureus, S. epidermidis and Enterococcus faecalis at minimal inhibitory concentrations (MIC) of 12.5 μg/ml and 12.5–25 μg/ml, respectively. Interestingly, 6 and 8 were also identified as constituents of an extract derived from a healthy plant sample of the host plant U. picroides thereby indicating that the production of bioactive natural products by the endophyte proceeds also under in situ conditions within the host plant. 相似文献
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Porwal S Kumar T Lal S Rani A Kumar S Cheema S Purohit HJ Sharma R Singh Patel SK Kalia VC 《Bioresource technology》2008,99(13):5444-5451
Thirty five bacterial isolates from diverse environmental sources such as contaminated food, nitrogen rich soil, activated sludges from pesticide and oil refineries effluent treatment plants were found to belong to Bacillus, Bordetella, Enterobacter, Proteus, and Pseudomonas sp. on the basis of 16S rRNA gene sequence analysis. Under dark fermentative conditions, maximum hydrogen (H2) yields (mol/mol of glucose added) were recorded to be 0.68 with Enterobacter aerogenes EGU16 followed by 0.63 with Bacillus cereus EGU43 and Bacillus thuringiensis EGU45. H2 constituted 63–69% of the total biogas evolved. Out of these 35 microbes, 18 isolates had the ability to produce polyhydroxybutyrate (PHB), which varied up to 500 mg/l of medium, equivalent to a yield of 66.6%. The highest PHB yield was recorded with B. cereus strain EGU3. Nine strains had high hydrolytic activities (zone of hydrolysis): lipase (34–38 mm) – Bacillus sphaericus strains EGU385, EGU399 and EGU542; protease (56–62 mm) – Bacillus sp. strains EGU444, EGU447 and EGU445; amylase (23 mm) – B. thuringiensis EGU378, marine bacterium strain EGU409 and Pseudomonas sp. strain EGU448. These strains with high hydrolytic activities had relatively low H2 producing abilities in the range of 0.26–0.42 mol/mol of glucose added and only B. thuringiensis strain EGU378 had the ability to produce PHB. This is the first report among the non-photosynthetic microbes, where the same organism(s) – B. cereus strain EGU43 and B. thuringiensis strain EGU45, have been shown to produce H2 – 0.63 mol/mol of glucose added and PHB – 420–435 mg/l medium. 相似文献
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Zunsheng Wang Zhuojing He Suxia Li Qinsheng Yuan 《Enzyme and microbial technology》2005,36(7):862-869
Cordyceps militaris mycelium produced mainly Cu, Zn containing superoxide dismutase (Cu, Zn-SOD). Cu, Zn-SOD activity was detectable in the culture filtrates, and intracellular Cu, Zn-SOD activity as a proportion protein was highest in early log phase culture. The effects of Cu2+, Zn2+, Mn2+ and Fe2+ on enzyme biosynthesis were studied. The Cu, Zn-SOD was isolated and purified to homogeneity from C. militaris mycelium and partially characterized. The purification was performed through four steps: (NH4)2SO4 precipitation, DEAE-sepharose™ fast flow anion-exchange chromatography, CM-650 cation-exchange chromatography, and Sephadex G-100 gel filtration chromatography. The purified enzyme had a molecular weight of 35070 ± 400 Da and consisted of two equal-sized subunits each having a Cu and Zn element. Isoelectric point value of 7.0 was obtained for the purified enzyme. The N-terminal amino acid sequence of the purified enzyme was determined for 12 amino acid residues and the sequences was compared with other Cu, Zn-SODs. The optimum pH of the purified enzyme was obtained to be 8.2–8.8. The purified enzyme remained stable at pH 5.8–9.8, 25 °C and up to 50 °C at pH 7.8 for 1.5 h incubation. The purified enzyme was sensitive to H2O2, KCN. 2.5 mM NaN3, PMSF, Triton X-100, β-mercaptoethanol and DTT showed no significant inhibition effect on the purified enzyme within 5 h incubation period. 相似文献
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古尼虫草胞内多糖高产培养基优化研究 总被引:1,自引:0,他引:1
以古尼虫草Cordyceps gunnii胞内多糖产量为目标,利用单因素法筛选古尼虫草产胞内多糖的最适碳源、氮源和无机盐,运用正交试验筛选最佳培养基组合,用最佳培养基研究古尼虫草产胞内多糖的发酵动力学。结果表明:古尼虫草产胞内多糖最佳培养基为葡萄糖35g/L、蛋白胨15g/L、硫酸锌1g/L、KH2PO4 1g/L、K2HPO4 0.5g/L,用最佳培养基获得胞内多糖(5.169±0.274)g/L,产量是优化前的1.81倍;动力学研究表明,144h是古尼虫草胞内多糖最佳培养时间,此时产量最高为(6.794±0.221)g/L,是目前报道古尼虫草胞内多糖的最高产量。 相似文献
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在大型真菌原基形成和子实体发育的过程中,温度是一个极其关键的因素,高温显著影响多种食用菌原基的形成和子实体的品质。广东虫草是中国华南地区特有的虫草类新食品原料,其子实体富含多种活性成分和营养成分,且能够进行较大规模人工栽培。然而,温度对广东虫草原基形成的影响及调控机制尚不清楚。本研究通过不同温度处理不同时间段,发现29℃处理3d抑制了广东虫草原基的形成;对29℃处理3d处理前后的菌丝阶段(CK)和原基阶段(CK-P和HT-P)样品进行转录组测序分析,高温处理后原基阶段的两个组中发现1 682个差异表达基因,其中1 015个上调表达和667个下调表达。在碳水化合物代谢途径中,多个糖酵解和三羧酸循环及葡聚糖和海藻糖合成相关基因在高温处理后呈现下调表达;在原基样品中,多个热激蛋白基因(Hsp10、Hsp23、DnaJ、Hsp70、Hsp90和Hsp98)和转录因子C2H2转录水平显著上调表达。本研究结果基于分子水平揭示了高温影响原基形成过程中能量代谢和相关基因的差异表达,为后续利用广东虫草抗逆相关基因资源培育新品种奠定了重要的基础。 相似文献
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Hofer E Keplinger F Thurner T Wiener T Sanchez-Quintana D Climent V Plank G 《Biosensors & bioelectronics》2006,21(12):2232-2239
A new flexible sensor for in vitro experiments was developed to measure the surface potential, Φ, and its gradient, E (electric near field), at given sites of the heart. During depolarisation, E describes a vector loop from which direction and magnitude of local conduction velocity θ can be computed. Four recording silver electrodes (14 μm × 14 μm) separated by 50 μm, conducting leads, and solderable pads were patterned on a 50 μm thick polyimide film. The conductive structures, except the electrodes, were isolated with polyimide, and electrodes were chlorided. Spacer pillars mounted on the tip fulfil two functions: they keep the electrodes 70 μm from the tissue allowing non-contact recording of Φ and prevent lateral slipping. The low mass (9.1 mg) and flexibility (6.33 N/m) of the sensor let it easily follow the movement of the beating heart without notable displacement. We examined the electrodes on criteria like rms-noise of Φ, signal-to-noise ratio of Φ and E, maximum peak-slope recording dΦ/dt, and deviation of local activation time (LAT) from a common signal and obtained values of 24–28 μV, 46 and 41 dB, 497–561 V/s and no differences, respectively. With appropriate data acquisition (sampling rate 100 kHz, 24-bit), we were able to record Φ and to monitor E and θ on-line from beat-to-beat even at heart rates of 600 beats/min. Moreover, this technique can discriminate between uncoupled cardiac activations (as occur in fibrotic tissue) separated by less than 1 mm and 1 ms. 相似文献
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Alpha-amylase of B. amyloliquefaciens was used for the structural characterization of the amylopectin from waxy-rice starch. Fractions of -dextrins with a degree of polymerization (d.p.) <5000 were isolated from amylopectin hydrolysates after 1 and 3 h. φ,β-Limit dextrins were prepared by successive phosphorolysis and beta-amylolysis of the fractions and these were analysed by a second alpha-amylolysis. Based on the hydrolysis pattern, the limit dextrins were divided into two major groups, A and B, which possessed units of clusters of d.p. 100–200 and 90–130, respectively. An extensive alpha-amylolysis resulted in characteristic distributions of dextrins with d.p. <80 which represented branched building blocks. Type A dextrins possessed more larger building blocks with d.p. 40, but less intermediate and small blocks, than type B. The φ,β-limit dextrin of the original amylopectin had a distinct distribution enriched in small building blocks. A model is proposed in which the two types of dextrins originate from regular and less regular structural domains of the amylopectin fraction within the starch granules. 相似文献
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Binding of the C6-zinc cluster protein, AFLR, to the promoters of aflatoxin pathway biosynthesis genes in Aspergillus parasiticus 总被引:1,自引:0,他引:1
AFLR is a Zn2Cys6-type sequence-specific DNA-binding protein that is thought to be necessary for expression of most of the genes in the aflatoxin pathway gene cluster in Aspergillus parasiticus and A. flavus, and the sterigmatocystin gene cluster in A. nidulans. However, it was not known whether AFLR bound to the promoter regions of each of the genes in the cluster. Recently, A. nidulans AFLR was shown to bind to the motif 5′-TCGN5CGA-3′. In the present study, we examined the binding of AFLR to promoter regions of 11 genes in the A. parasiticus cluster. Based on electrophoretic mobility shift assays, the genes nor1, pksA, adhA, norA, ver1, omtA, ordA, and, vbs, had at least one 5′-TCGN5CGA-3′ binding site within 200 bp of the translation start site, and pksA and ver1 had an additional binding site further upstream. Although the promoter region of avnA lacked this motif, AFLR bound weakly to the sequence 5′-TCGCAGCCCGG-3′ at −110 bp. One region in the promoter of the divergently transcribed genes aflR/aflJ bound weakly to AFLR even though it contained a site with at most only 7 bp of the 5′-TCGN5CGA-3′ motif. This partial site may be recognized by a monomeric form of AFLR. Based on a comparison of 16 possible sites, the preferred binding sequence was 5′-TCGSWNNSCGR-3′. 相似文献
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结合形态学与ITS序列分析对7株野生虫草真菌进行分类鉴定。MTT法分析它们的菌丝体醇提取物对肝癌HepG2细胞增殖的抑制活性。鉴定结果表明菌株MF7、MF9、MF14为细脚棒束孢Isaria tenuipes,菌株MF11、MF12、MF13为蝉棒束孢Isaria cicadae,菌株MF10为球孢白僵菌Beauveria bassiana;MTT结果显示分离到的3株细脚棒束孢和3株蝉棒束孢的菌丝体醇提取物对HepG2的抑制活性较差,IC50均大于500μg/mL;球孢白僵菌MF10对HepG2细胞有一定抑制作用,IC50值为221.6μg/mL,略强于蝙蝠蛾拟青霉发酵菌丝粉产品金水宝胶囊(IC50=364μg/mL)和中华被毛孢发酵菌丝粉产品百令胶囊(IC50=268.7μg/mL)。另外,发现供对比试验的3株蛹虫草菌株(MF1、MF5、MF15)对HepG2细胞均有较好的抑制作用,其中MF15的发酵菌丝体醇提取物活性最强,IC50为55.56μg/mL,暗示蛹虫草发酵菌丝体具有重要的研究价值。 相似文献
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Influence of sucrose on the rheology and granule size of cross-linked waxy maize starch dispersions heated at two temperatures 总被引:4,自引:0,他引:4
Cross-linked waxy maize (CWM) starch dispersions (STDs) of concentration 50 g kg−1 were heated in sucrose solutions containing 0–600 g kg−1 (g sucrose/kg dispersion) at 85 °C at low shear and in intermittently agitated cans at 110 °C. The STDs heated in 0–300 g kg−1 sucrose exhibited antithixotropic behavior, while those heated in 400–600 g kg−1 sucrose exhibited thixotropic behavior. The mean starch granule diameter of the starch dispersions did not show strong dependence on sucrose concentration. The dispersions, especially those with high sucrose concentrations and heated at 110 °C, exhibited G′ versus frequency (ω) profiles of gels. The STDs exhibited first normal stress differences that increased in magnitude with the concentration of sucrose. Values of the first normal stress coefficient of canned dispersions calculated from dynamic rheological data plotted against ω and experimental values plotted against shear rate of some of the STDs overlapped. 相似文献
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为提高细脚棒束孢中N 6-(2-羟乙基)腺苷(简称HEA)的提取效率,在超声时间、提取液pH、料液比3个单因素试验的基础上,运用响应面法对超声提取细脚棒束孢中HEA工艺进行优化。结果表明,液料比对提取效果的影响最大,其次是提取液pH,超声时间因素影响最小。响应面法优化后,细脚棒束孢的最佳超声提取工艺为:超声时间31min、液料比22:1(mL/g)、pH 4.88,Box-Behnken模型预测值为0.86mg/g,实际值为(0.86+0.03)mg/g,二者偏差为0.10%,说明响应面优化超声提取细脚棒束孢中HEA工艺稳定可行。该研究所得提取工艺适用于不同虫草类真菌腺苷类成分的提取及分析,具有省时高效、节约能源的优势,可用于虫草的质量评价及开发等研究。 相似文献
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Andrew P. Negri Christopher J.S. Bolch Stephanie Geier David H. Green Tae-Gyu Park Susan I. Blackburn 《Harmful algae》2007,6(6):774-780
The toxic dinoflagellate Gymnodinium catenatum Graham produces a newly discovered sub-class of paralytic shellfish toxins (PSTs, saxitoxins) that contain a hydroxybenzoate moiety in place of the carbamoyl group (GC toxins: GC1–GC3). GC toxins bind strongly to sodium channels and their lipophilic nature may increase their potential to bioaccumulate in marine organisms. Cultures Australian G. catenatum strains were found to contain 12–63 mol% GC toxins. The GC toxins were also detected in strains from China (38 mol%), Japan (1–2 mol%), Portugal (58 mol%), Spain (36–54 mol%), and Uruguay (10–16 mol%). A cluster analysis of molar proportions of saxitoxin derivatives produced by strains showed clear clustering by country/region of origin, indicating that GC toxins may be very useful markers to identify the source of G. catenatum in the case of new outbreaks. The GC toxins dominate the toxin profiles of many G. catenatum strains, and can contribute significantly to sample toxicity, yet these toxins may easily escape detection using conventional chromatography, resulting in significant underestimates of sample toxicity. This has significant implications for shellfish monitoring and safety. 相似文献
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Chromium and salt tolerance in five indigenous cyanobacterial strains isolated from contaminated sites was investigated along with their metal bioaccumulative potential. All the five species showed significantly better growth when the medium was spiked with salt or chromium. As compared to single metal or salt treatment, the binary metal–salt (MS) treatments had more favorable effect on cyanobacterial growth as indicated by significantly higher concentration of the primary photosynthetic pigment chlorophyll at M20S2000 (9.9–25.3 μg/mL) as compared to that at M0S0 (4.0–12.3 μg/mL). Similarly biomass was much higher at M20S1000 and M20S2000 (41.8–86.2 mg/10 mL) as compared to that at control, M0S0 (21.5–36.3 mg/10 mL). Accessory pigments like carotenoids and phycobilinproteins too tended to increase significantly in response to both metal and salts in the two species of Lyngbya (L. putealis and L. ceylanica var. constricta) and Gloeocapsa. These species also showed greater potential of chromium bioaccumulation, which increased further as both salt and metal concentration increased. In the two species of Nostoc however, bioaccumulative potential improve at higher metal concentration, but not affected significantly by salt concentration. 相似文献
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The examination of macrophyte, water and sediment samples, collected at depths less than 1.5 m from 50 different sites along the North Aegean coasts, has revealed, for the first time in Greek coastal waters, the presence of two Ostreopsis species (O. ovata and O. cf. siamensis) and Coolia monotis in the majority of the sampling sites (94% and 100%, respectively). Other epiphytic dinoflagellates of the genera Prorocentrum and Amphidinium and diatoms were accompanying species in this epiphytic community. Morphometric features, plate formula and thecal ornamentation were used for species identification. O. ovata cells were smaller in dorsoventral (DV) diameter and width (W) (26.18–61.88 μm and 13.09–47.60 μm, respectively) in comparison with O. cf. siamensis (35.70–65.45 μm and 23.80–49.98 μm, respectively). In contrast, the anterioposterior (AP) diameter of O. cf. siamensis was smaller (14.28–26.18 μm) resulting in DV/AP ≈ 3, whereas the above ratio for O. ovata was less than 2 (AP ranging between 14.28–35.70 μm). Moreover, the theca of O. ovata cells was ornamented with scattered pores, which fluctuated in a wider range (0.07–0.32 μm) than those of O. cf. siamensis (0.23–0.29 μm). Coolia monotis cells were almost round with average DV diameter 26.88 μm, AP 25.66 μm and width 26.76 μm. Small and large cells were recorded in both field and culture populations of Ostreopsis spp. and C. monotis, while hyaline cysts were observed for O. ovata. The presence of O. ovata and O. cf. siamensis exhibited a clear seasonal pattern dominating (maximum abundance up to 4.05 × 105 cells gr−1 fwm) the period from midsummer to late autumn in years 2003 and 2004, while C. monotis was found also in winter and spring months. 相似文献