干巴菌菌丝营养生理特性的初步研究

本文报道了不同碳源、氮源、微量元素及维生素培养基对干巴菌菌丝生长的影响。试验表明，干巴菌菌丝利用最好的的碳源是葡萄糖，其次是蔗糖。利用最好的氮源是硝酸钙，其次是硝酸铵和硫酸铵，对蛋白胨和尿素的利用效果差。缺少碳源或氮源时，菌丝生长细弱、稀少，不形成原基。微量元素和维生素均对干巴菌菌丝生长有促进作用，其中以锰、铜和维生素Ｂ２的作用尤为突出。     

橡胶树胶乳全蛋白的提取及双向电泳分析

以橡胶树无性系RRIM600为材料，采用TCA(三氯乙酸)-丙酮沉淀法提取胶乳全蛋白，17 cm pH 5～8固相pH梯度预制干胶条和快速银染法对提取的蛋白进行分离和染色，所得到的电泳图谱背景清晰，横条纹和竖条纹少，且蛋白点数量多。通过本研究获得了高分辨率的胶乳全蛋白双向电泳(2-DE)图谱的方法，为进一步开展橡胶树胶乳全蛋白质组学研究奠定了基础。     

Nodule phosphorus requirement and O2 uptake in common bean genotypes under phosphorus deficiency

Abstract

The effect of P deficiency on nodulation, nodule P content, nodule O₂ permeability and N fixation rates in Phaseolus vulgaris–rhizobia symbiosis was studied under glasshouse conditions. Four recombinant inbred lines (L34, L83, L115 and L147) and one variety cultivated in Morocco (Concesa) were inoculated with Rhizobium tropici CIAT 899 in hydroaeroponic culture. Two P levels i.e. 75 (deficient level) and 250 µmol plant^?1 week^?1 P (sufficient level) were applied and the trial was assessed 42 days after transplanting that coincide with plant flowering stage. Under P-deficiency, decrease of plant growth (18%) and nodule biomass (19%) was detected and significantly pronounced in the sensitive line L147 compared with the remaining genotypes. Additionally, under P-deficiency, the efficiency in use of rhizobial symbiosis, estimated by the slope of the regression model of shoot biomass as a function of nodule biomass, was significantly increased in the four lines. This constraint did not significantly influence nodule P content in Concesa, but it was 24 and 41% lower in the tolerant and in the sensitive lines, respectively. Nodule P content was positively correlated to nodule biomass, r=0.75, and shoot N, r=0.92. These genotypic variations were associated with variability in nodule O₂ permeability that was significantly affected by the P level-bean genotype interaction. Under P-deficiency, nodule O₂ permeability was significantly reduced in the tested genotypes and accompanied with a decrease in shoot N content, especially in the sensitive lines (35%). Moreover, the ratios plant N fixed: nodule P content and plant N fixed:nodule dry weight were affected under P-deficiency in four lines with an exception observed in Concesa. Depending on the observed data we concluded that N₂ fixation efficiency could be influenced by nodulation and level of nodule P requirement which depend on both bean genotypes and P level.     

西番莲多糖提取物对猪圆环病毒2型感染RAW264.7细胞氧化应激的影响

为研究西番莲多糖提取物（Passiflora edulis polysaccharide extract，PEPE）对猪圆环病毒2型（Porcine circovirus type 2，PCV2）感染RAW264.7细胞氧化应激相关因子的影响，本试验探讨了PEPE对氧化应激的调节作用。在96孔细胞培养板中每孔加入100 μL浓度为1×10⁶个/mL的RAW264.7细胞，分别设细胞对照组、PEPE组（25、50、100、200、400、800和1 600 μg/mL），分别于培养箱培养24和48 h，用MTT法检测细胞活性，筛选PEPE的药物安全浓度范围。试验分为以下6个组：细胞对照组、病毒组、PEPE高（400 μg/mL）、中（200 μg/mL）、低（100 μg/mL）剂量组及维生素C组，其中细胞对照组加入含10% FBS的DMEM培养液，其余组加入PCV2病毒液，孵育2 h后在PEPE组加入对应浓度的PEPE溶液，VC组加入配制好的VC溶液，细胞对照组和病毒组加入含10% FBS的DMEM培养液，培养48 h，同样用MTT法检测细胞活性，以研究PEPE对PCV2感染RAW264.7细胞活性的影响。按照上述6个试验组分组，处理同上，将细胞培养12 h，收集样品用于检测氧化应激相关因子水平。用Griess法和DCFH-DA荧光探针分别检测RAW264.7细胞上清中NO含量和细胞内活性氧（ROS）水平、OPT荧光法检测细胞内还原型谷胱甘肽（GSH）和氧化型谷胱甘肽（GSSG）含量，化学发光法检测细胞内黄嘌呤氧化酶（XOD）、髓过氧化物酶（MPO）和诱导型一氧化氮合酶（iNOS）活力。结果显示，PEPE对RAW264.7细胞的安全浓度范围为25~400 μg/mL。PCV2感染RAW264.7细胞后，细胞活性显著降低（P<0.05），而不同浓度PEPE处理组均能提高细胞活性。RAW264.7细胞被PCV2感染后，细胞分泌NO、ROS水平，GSSG含量及XOD、MPO和iNOS活性显著升高（P<0.05），感染细胞GSH含量显著降低（P<0.05）；PEPE作用于PCV2感染的RAW264.7细胞，显著降低感染细胞NO、ROS水平、GSSG含量及XOD、MPO和iNOS活性（P<0.05），100 μg/mL PEPE处理组细胞GSH水平显著升高（P<0.05）。本试验结果表明，PEPE能提高PCV2感染RAW264.7细胞的抗氧化能力，有利于缓解病毒感染所致氧化应激。     

中国历史最悠久的高等学府从岳麓书院到湖南大学

湖南大学与岳麓书院一脉相承.湖南大学校史应从岳麓书院创建之年公元976年算起,历史上的各种文献资料早有志述,书院学制沿革、校史沿革等资料确凿可证,应以其千年历史沿革载入中国教育史册和世界教育史册.     

甜瓜不同生育期日光温室CO2浓度的变化

日光温室秋冬茬甜瓜在施足有机肥和秸秆堆肥时,生长前期棚内CO2浓度较高,中午12:00左右放风时棚内CO2浓度缓苗期为1 810 mg·L-1,留瓜期1 200 mg·L-1,授粉期1 370 mg·L-1;授粉期夜间CO2积累最快,平均增加140 mg·L-1·h-1;膨大期放风前冠层CO2下降量最大,平均每10 min(分)下降150 mg·L-1;垄面土壤平均比沟内CO2释放量多142 g·m-2·h-1.     

钾硅钙微孔矿物肥对水稻重金属镉的降阻效果研究

为了探明钾硅钙微孔矿物肥对污染稻田土壤重金属镉(Cd)有效性的影响,弄清其对稻谷中Cd含量的降低效果。采用田间小区试验和室内分析测定方法进行研究,试验设5个处理,处理1:对照(CK),常规施肥(40%复合肥450 kg/hm2);处理2:钾硅钙微孔矿物肥600 kg/hm2+常规施肥;处理3:钾硅钙微孔矿物肥750 kg/hm2+常规施肥;处理4:钾硅钙微孔矿物肥1125 kg/hm2+常规施肥;处理5:钾硅钙微孔矿物肥1425 kg/hm2+常规施肥。结果表明:钾硅钙微孔矿物肥可以显著提高水稻穗总粒数、穗实粒数和结实率,提高水稻产量,增产率达到7.5%~16.0%;增加土壤碱解氮、有效磷和速效钾含量,提高土壤pH值,降低土壤有效Cd含量,从而降低稻谷Cd的积累,最大降低稻谷Cd含量达到38.6%。钾硅钙微孔矿物肥要达到降阻水稻重金属Cd的最佳效果,施用量不能低于1425 kg/hm2。     

外源Ca~(2+)对莲藕幼苗盐胁迫的缓解效应

以莲藕H_2(花藕品种,盐敏感)为材料,利用NaCl与Ca(NO_3)_2处理3片立叶的幼苗,研究外源Ca~(2+)对缓解植株盐胁迫的生理作用。结果显示:采用NaCl处理后,叶片中叶绿素、可溶性蛋白含量和SOD活性显著降低,而细胞膜透性、丙二醛和脯氨酸含量升高;利用不同浓度的Ca~(2+)进行缓解处理,发现外源施加低浓度的Ca~(2+)后,叶片叶绿素、可溶性蛋白含量和SOD活性均显著提高,脯氨酸含量较之前升高幅度更大,而细胞膜透性和丙二醛含量后期显著降低,说明Ca~(2+)对缓解莲藕盐胁迫具有较好的效果。当Ca~(2+)浓度增加时,缓解作用不明显,甚至出现抑制效果。     

Protective mechanism of metallothionein on cultivated rat cardiomyocytes in hypoxic preconditioning

AIM: Studying the mechanism of protective role of metallothionein(MT) in hypoxic preconditioning(HPC) of cultivated rat cardiomyocytes. METHODS:Using the model of hypoxia/reoxygenation of cultivated rat cardiomyocytes. Determining the contents of MT, malonyldialdehyde (MDA)-metabolism product of lipid peroxidation and the activities of Na⁺-K⁺ATPase, Ca²⁺-Mg²⁺ATPase of cardiomyocytes 24h after HPC, also determining the relevant changes after using MT antibody. RESULTS: After 24 h in HPC, the contents of MT and activities of Na⁺-K⁺ATPase, Ca²⁺-Mg²⁺ATPase were obviously higher than those in the control and hypoxia/reoxygenation(P＜0.05), and the contents of MDA were decreased remarkedly (P＜0.01). Then after using MT antibody, the activities of two enzyme were progressively decreased and the contents of MDA were significantly higher than those in the control and MT antibody-free groups(P＜0.01). CONCLUSION: HPC may induce excessive synthesis of MT, and MT can protect myocardial reoxygenation injury by eliminating lipid peroxidation and rising the activities of Na⁺-K⁺ATPase and Ca²⁺-Mg²⁺ATPase.