Isolation and characterization of endophytic fungi from Camptotheca acuminata

In this study, a total of 161 endophytic fungal isolates from Camptotheca acuminata were obtained and classified to 16 taxa according to morphological and molecular analysis. These taxa were composed of 2 frequent genera (Botryosphaeria and Fusarium) and 14 infrequent groups such as Xylaria, Diaporthe, Rhizopus, Epicoccum, and Preussia, demonstrating that fungal endophytes in C. acuminata were highly abundant and diverse. Antimicrobial activity screening using filter-paper diffusion method showed that 47.6 % of the tested isolates had antimicrobial activity against at least one of the test microorganisms. Screening of fungal endophyte-derived camptothecin analogues by TLC and LC–MS/MS³ demonstrated that a strain Botryosphaeria dothidea, X-4 could produce 9-methoxycamptothecin (9-MCPT) when cultured in Sabouraud’s dextrose broth for 12 days under shake flask and bench-scale fermention conditions. This work showed that the fungal endophytes from C. acuminata could be an alternative source for the production of 9-MCPT and other natural antimicrobial compounds.     

大孔树脂分离纯化“黑金刚”紫马铃薯花青苷工艺研究

以紫色马铃薯"黑金刚"花青苷为原料,采用D101、HDP100A、HDP450A、NK-9、AB-8五种大孔吸附树脂对花青苷的吸附与解析特性进行了比较研究,并在此基础上,采用最佳大孔树脂对花青苷纯化过程中的静态、动态吸附和解析附条件进行了优化研究。结果表明AB-8大孔树脂具有较好的吸附和解析能力,是纯化紫色马铃薯花青苷的最佳树脂,较优纯化条件为:上样液花青苷浓度为0.028mg.g-1,上样液pH=2,洗脱液乙醇浓度为50%,洗脱液pH=1,吸附流速为1mL.min-1,洗脱流速为1mL.min-1。经大孔树脂纯化后,色价值比纯化前提高了7.55倍。     

植物对氨基酸的吸收研究进展

氨基酸在提高植物产量、改善产品品质、增强植株抗逆性、保护生态环境等方面发挥着越来越重要的作用,在农业生产中越来越受到重视。本文简述了氨基酸含量、氨基酸种类和植物种类对植物吸收氨基酸的影响,并对氨基酸营养研究进行展望,以期提高人们对植物氨基酸营养的认识,促进氨基酸在农业中的应用和发展。     

FHSA-SED: Two-Locus Model Detection for Genome-Wide Association Study with Harmony Search Algorithm

Motivation

Two-locus model is a typical significant disease model to be identified in genome-wide association study (GWAS). Due to intensive computational burden and diversity of disease models, existing methods have drawbacks on low detection power, high computation cost, and preference for some types of disease models.

Method

In this study, two scoring functions (Bayesian network based K2-score and Gini-score) are used for characterizing two SNP locus as a candidate model, the two criteria are adopted simultaneously for improving identification power and tackling the preference problem to disease models. Harmony search algorithm (HSA) is improved for quickly finding the most likely candidate models among all two-locus models, in which a local search algorithm with two-dimensional tabu table is presented to avoid repeatedly evaluating some disease models that have strong marginal effect. Finally G-test statistic is used to further test the candidate models.

Results

We investigate our method named FHSA-SED on 82 simulated datasets and a real AMD dataset, and compare it with two typical methods (MACOED and CSE) which have been developed recently based on swarm intelligent search algorithm. The results of simulation experiments indicate that our method outperforms the two compared algorithms in terms of detection power, computation time, evaluation times, sensitivity (TPR), specificity (SPC), positive predictive value (PPV) and accuracy (ACC). Our method has identified two SNPs (rs3775652 and rs10511467) that may be also associated with disease in AMD dataset.     

菌根真菌对白及种子萌发和幼苗生根的作用

自然条件下,兰科植物需要依赖菌根真菌获得营养才能萌发。本研究对白及根和原球茎中分离的4株菌根真菌（WQ17-33、WQ17-43、JST-3和SL15-7）进行分子鉴定,并评价光照和黑暗条件下不同菌株促白及种子萌发和幼苗生根的效果。结果表明,4个菌株分别隶属于鬼伞属Coprinus、胶膜菌属Tulasnella、腊壳菌属Sebacina和Serendipita。在种子萌发前期（未形成叶子）进行暗培养较光照对菌株JST-13和SL15-7处理组原球茎阶段萌发具有显著的促进作用。不同菌株共生萌发效果不同,菌株SL15-7较其他处理原球茎和幼苗发育阶段的萌发率高。菌株JST-13和SL15-7处理组形成的幼苗较其他处理组强壮,定殖的菌丝团也较多,其幼苗生根效果也较对照组好。该研究表明白及可与多种不同类群的菌根真菌菌株形成共生关系,这些真菌在促进白及种子萌发和生根能力方面存在差异。     

蒲公英植酸对沙门氏菌抑制作用及其抑菌机理研究

为探究蒲公英植酸对沙门氏菌的抑制作用及其抑菌机理。本文利用沉淀法和离子交换法提取蒲公英植酸,滤纸片法分析蒲公英植酸对沙门氏菌(Salmonella)的抑菌作用,倍比稀释法研究蒲公英植酸的最低抑菌浓度。通过分析沙门氏菌的细胞通透性和生长动力学,结合扫描电镜和荧光显微镜研究了蒲公英植酸对沙门氏菌的抑菌机理,表明蒲公英植酸对沙门氏菌具有很好的抑菌能力,其最小抑菌浓度为0.2 mg/mL。而且植酸对沙门氏菌的抑制作用是通过破坏细胞膜达到抑菌的效果,并且植酸浓度越高,抑菌效果越显著。这表明蒲公英植酸可以有效地抑制沙门氏菌生长,其主要是通过破坏菌体细胞膜完整性,增加细胞薄膜的通透性,使细胞内容物外溢达到抑制细菌生长的目的。     

大鲵皮肤色素提取工艺及抗氧化研究

为优化大鲵皮肤黑色素的提取工艺条件,探讨大鲵皮肤黑色素组成成分及体外抗氧化活性,采用酶法和碱溶酸沉法提取大鲵皮肤黑色素,以氢氧化钠浓度、液料比、提取温度为影响色素提取率因素,优化黑色素提取工艺条件,用紫外-可见光谱仪、红外光谱仪和超高效液相质谱仪测定黑色素的光谱特性,测定其抗氧化性。结果表明:大鲵皮肤黑色素最佳提取工艺条件为氢氧化钠浓度1.5 mol/L、液料比1∶15、提取温度45℃,黑色素提取率达0.65%。大鲵皮肤黑色素的紫外最大吸收波长为214 nm,由真黑色素和脱黑色素两种色素组成,其对超氧阴离子自由基的清除率为30.51%,对羟基自由基的清除率为54.17%。大鲵皮肤黑色素具有一定的体外抗氧化能力。     

黄酒酿造原料及生产工艺研究现状与展望

黄酒的质量取决于酿造原料、酒曲、加工工艺以及酿造环境,不同的酿造原料、酒曲、加工工艺和环境能赋予黄酒不同的品质与风味。本文在检索文献、比较分析新旧版黄酒国标的基础上,介绍了南北地区黄酒酿造原料的差异以及新型功能性黄酒原辅料研发现状,综述了浸米、蒸饭与发酵三个工艺关键环节的最新研究进展,旨在为黄酒技术的创新,功能性、饮料性、国际性黄酒新产品开发提供借鉴及参考。