The selection of alkaline protease-producing yeasts fi＇om marine environments and evaluation of their bioactive peptide production

A total of 400 yeast strains from seawater, sediments, saltern mud, marine fish guts, and marine algae were obtained. The protease activity of the yeast cultures was estimated, after which four strains (HN3.11, N11b, YF04C and HN4.9) capable of secreting extracellular alkaline protease were isolated. The isolated strains were identified as Aureobasidium pullulans, Yarrowia lipolytica, Issatchenkia orientalis and Cryptococcus cf. aureus. The optimal pH of the protease activity produced by strains HN3.11, YF04C, and HN4.9 was 9.0, while that of the protease produced by strain N11b was 10.0. The optimal temperature for protease activity was 45°C for strains HN3.11, N11b, and YF04C, and 50°C for strain HN4.9. After digestion of shrimp (Penaeus vannamei) protein and spirulina (Arthospira platensis) protein with the four crude alkaline proteases, the filtrate from spirulina (Arthrospira platensis) powder digested by the crude alkaline protease of strain HN3.11 was found to have the highest antioxidant activity (61.4%) and the highest angiotensin I converting enzyme (ACE)-inhibitory activities (68.4%). The other filtrates had much lower antioxidant activity and ACE-inhibitory activities.     

海南红树林内生真菌Endomelanconiopsis endophytica次级代谢产物及其体外生物活性

【目的】研究源自海南红树林植物角果木(Ceriops tagal)内生真菌Endomelanconiopsis endophytica的次级代谢产物及其体外生物活性。【方法】利用正相硅胶柱层析、反相ODS柱层析、Sephadex LH-20凝胶柱层析、半制备高效液相色谱等色谱分离方法,对该菌发酵产物的乙酸乙酯浸膏的次级代谢产物进行分离纯化;综合利用核磁共振波谱(NMR)、质谱(MS)等波谱学技术以及与文献数据比对,鉴定化合物的结构;并对化合物进行体外细胞毒活性和免疫抑制活性评价。【结果】从内生真菌Endomelanconiopsis endophytica中分离得到9个化合物,其结构分别鉴定为(4E,8E)-2-N-(2-hydroxypalmitoyl)-1-O-(β-D-glucopyranosyl)-9-methyl-4,8-sphingadienine(Ⅰ)、2-(1-hydroxyethyl)quinazolin-4(3H)-one(Ⅱ)、uridine(Ⅲ)、citreoisocoumarinol(Ⅳ)、5-hydroxymellein(Ⅴ)、roccellatol(Ⅵ)、...     

Antiangiogenic activity of low-temperature lysozyme from a marine bacterium <Emphasis Type="Italic">in vivo</Emphasis> and <Emphasis Type="Italic">in vitro</Emphasis>

We extracted marine low-temperature lysozyme (MLTL), a novel lysozyme, from a marine microorganism through fermentation. Our previous study suggested that a low molecular weight (16 kDa) may exert anti-tumor activity through antiangiogenesis. In this study, we extracted a high weight (39 kDa) and investigated its antiangiogenic activity in vivo and in vitro. Using zebrafish embryos as an in vivo study model, we found that treatment with MLTL significantly inhibited the growth of subintestinal vessels (SIVs) in a dose-dependent manner and that 400 μg/ml MLTL was sufficient to block the growth of SIVs. An in vitro study conducted using human umbilical vein endothelial cells (HUVECs) revealed that MLTL suppressed the proliferation, migration and tube formation of HUVECs in a dose-dependent manner. Interestingly, assays by flow cytometry and DNA electrophoresis indicated that MLTL was able to induce apoptosis of HUVECs. Moreover, further study demonstrated that the disruption of intracellular Ca²⁺ homeostasis may play an important role in MLTL induced apoptosis of HUVECs. Taken together, the results of this study demonstrate for the first time that MLTL inhibits angiogenesis through its pleiotropic effects on vascular endothelial cells and induces apoptosis through regulation of cellular Ca²⁺ levels. The results of this study also revealed a possible mechanism underlying the antiangiogenic effect of MLTL and suggested that MLTL may be a promising new antiangiogenic agent for use in cancer therapy.     

BS活性土壤生态

公司简介;技术原理;技术特点;施工流程     

冻藏龙眼果皮细胞膜透性、PPO活性和酚类物质含量的变化

将“油谭本”龙眼在-40℃条件下进行速冻，然后转入-18℃恒定低温冷库中冻藏180d。测定了龙眼果实速冻时的冻结曲线、冻藏过程中果皮细胞膜渗透率、果皮内PPO的活性和总酚含量的变化情况。试验结果表明，-40℃的冷冻温度即可满足速冻要求；冻藏可以有效地抑制果皮内PPO的活性，果皮细胞膜渗透率和总酚含量的变化较小，能够较好地保持果实的外观品质。     

Labile organic matter content and distribution as affected by six-year soil amendments to eroded Chinese mollisols

Labile organic carbon （LOC） is a fraction of soil organic carbon （SOC） with rapid turnover time and is affected by soil fertilization. This investigation characterized the SOC content, LOC content and LOC distribution in the treatment plots of surface soil erosion at five levels （0-, 5-, 10-, 20- and 30-cm erosion）. The soil had received contrasting fertilizer treatments （i.e., chemical fertilizer or chemical fertilizer ＋ manure） for 6 years. This study demonstrated that both SOC and various LOC fractions contents were higher in the plots with fertilizer ＋ manure than in those with fertilizer alone under the same erosion conditions. The SOC and LOC contents de- creased as the erosion depth increased. Light fraction organic carbon, particulate organic carbon, easily oxidizable organic carbon （KMnO4-oxydizable organic carbon）, and microbial biomass carbon were 27% 57%, 37%-7%, 20%-25%, and 29%-33% higher respectively in the fertilizer ＋ manure plots, than in the fertilizer alone plots. Positive correlations （p 〈 0.05） between SOC content and different fractions contents were observed in all plots except the correlation between total SOC content and water-soluble organic carbon content in the different fertilization treatments. Obviously, fertilizer ＋ manure treatments would be conducive to the accumulation of LOC and SOC in the Black soil of Northeast China.     

南极青霉菌Penicillium sp.S-1-16摇瓶发酵条件的初步优化

对一株具有细胞毒活性的南极青霉属真菌Penicillium sp.S-1-16进行发酵条件的初步优化。通过对基础发酵培养基、发酵温度及培养基配制用水的筛选,以次级代谢产物量为主要指标,同时参考生物量及细胞毒活性指标来进行初步优化,获得一个较优的摇瓶发酵条件:酵母提取粉0.3%,蛋白胨0.5%,麦芽糖0.3%,葡萄糖1%,蔗糖5%,自来水,初始p H=7.0,接种量15%,18℃,180 r·min-1发酵15 d。采用初步优化后的条件进行发酵,与初始发酵条件相比,其次级代谢产物量提高到568.75%,对A549肿瘤细胞的抑制作用增强至265%,并且对He La肿瘤细胞和SGC-7901肿瘤细胞的抑制率分别从0提高到48.19%和69.18%,效果显著,为获得菌株中活性次级代谢产物奠定了基础。     

拮抗香蕉枯萎病菌海洋细菌的筛选和鉴定

从93份中国南部海域近海海泥样品中分离出1800多株海洋细菌,以对峙培养法,测定海洋细菌对香蕉枯萎菌的拮抗作用,再以琼脂划线培养法(agar streak)测定菌株的抑菌活性,结果表明:约55.6%的菌株对香蕉枯萎菌有一定的拮抗作用,其中58株菌株抑制香蕉枯萎菌生长所形成的抑菌带宽度大于10.0mm,抑菌作用较好,复筛后其中13个菌株形成的抑菌带宽在15.0mm以上。经反复转接和对峙培养,筛选出拮抗效果好、抑菌活性稳定的菌株TC-1,初步鉴定为芽孢杆菌属的细菌,TC-1对14种病原微生物都有较好的抑菌效果。     

影响浸铀细菌活性的因素初探

微生物浸铀技术可以大幅度提高难浸铀矿石的浸出率 ,其关键技术是培养高活性的菌种。为了培养能适应多种恶劣条件的高活性菌种 ,必须对影响浸铀微生物活性的各种因素进行研究。通过实验室对浸铀细菌硫杆菌属中的氧化亚铁硫杆菌的活性因素的研究 ,并结合实际对从江西山南矿区的野外矿样中分离筛选出的菌株的活性的影响因素作了初步探讨 ,认为pH值为 1 8、温度为 30℃、接种量为 2 0 %及 90r/min的充气条件是该硫杆菌最佳的培养条件。通过对磷、铀两种元素在不同浓度下对细菌活性影响的试验 ,得出高浓度的磷、铀对细菌有明显的抑制作用 ,但通过驯化可以降低及弱化这种抑制作用。