CIDEC的亚细胞定位及其功能初步研究

CIDEC(也称FSP27)高表达于脂肪组织,可以促进细胞内脂肪积累等。为探究CIDEC促进脂滴融合的机制,本研究利用脂肪酸处理HepG2细胞,测定细胞内脂滴直径和数目的变化,发现处理后脂滴的直径和数量无显著性差异。将含有CIDEC的重组载体转染细胞,脂肪酸处理24 h后测定脂滴直径和数量变化,进一步利用共聚焦显微镜分析其亚细胞定位,并检测与脂滴生成、生长等相关基因表达量的变化。结果表明,过表达CIDEC后脂滴的直径显著增加,脂滴的数量极显著减少;亚细胞定位发现,CIDEC位于脂滴周围。此外,PLIN1、CREB1、CREB8的表达量有所下降,CIDEA、CFD表达量有所上升,推测CIDEC可能与这些蛋白互作引起脂滴融合。本研究结果为探究CIDEC促进脂滴融合的分子机制奠定了基础。     

无乳链球菌GD201008-001二元调控系统RscSR的鉴定及其对细菌应激适应性和毒力特性的影响

为鉴定鱼源无乳链球菌GD201008-001二元调控系统(two-component system, TCS)RscSR并探究其功能,实验利用生物信息学方法预测到可能的RscSR,对其组成成分RscS和RscR的三维结构和保守结构域进行分析;构建基因缺失株ΔrscSR与互补株CΔrscSR,测定细菌的生长曲线,检测其耐酸应激、耐氧化应激、抗巨噬细胞吞噬和胞内存活能力,同时测定其对巨噬细胞的毒性和对小鼠的毒力。结果显示,RscSR具有典型的TCS结构特点,其中RscS具有组氨酸激酶结构域,RscR具有反应调节子结构;其编码基因缺失后,菌株耐酸、耐氧化、抗巨噬细胞吞噬和胞内存活能力及对巨噬细胞毒性均显著降低,而将该基因回补后各项能力均有所恢复;动物实验结果显示,野生株感染小鼠19 h内全部死亡,而ΔrscSR缺失株感染小鼠全部死亡时间为48 h。研究表明,RscSR在无乳链球菌应激适应性以及毒力方面发挥重要作用。     

Effect of dietary GroBiotic®‐A supplementation as a prebiotic on the intestinal microflora,growth performance,haemato‐serological parameters,survival rate and body composition in juvenile beluga (Huso huso Linnaeus, 1754)

The objectives of the present study were to investigate of GroBiotic^®‐A (GBA) on growth, autochthonous intestinal microbiota and haemato‐serological parameters of beluga juvenile. A total of 180 fish (40.82 ± 5.81 g) were fed diets containing graded levels of GBA (0, 5, 10 and 20 g kg^?1 diet) for 8 weeks. No significantly differences in body composition, total viable aerobic bacteria, mean cell volume, mean cell haemoglobin, mean cell haemoglobin concentration, neutrophils, eosinophils, monocytes, albumin, glucose, triglyceride, cholesterol, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase were detected between treatment groups. The fish fed on 10 and 20 g kg^?1 GBA significantly showed higher lactic acid bacteria, final weight, body weight increases, weight gain and lower feed conversion ratio compared with the control and 5 g kg^?1 groups. The group fed 20 g kg^?1 GBA showed a highly significant difference in condition factor, survival rate, final length, total red and white blood cells, lymphocytes, haematocrit, haemoglobin, total protein, total immunoglobulin and lysozyme activity. The specific growth rate of the treatment groups was significantly elevated compared with the control groups. These results indicated that GBA at level 20 g kg^?1 improved growth, welfare and survival of beluga juvenile.     

Comparison of Salt and Drought‐Stress Effects on Maize Growth and Yield Formation with Regard to Acid Invertase Activity in the Kernels

The long‐term effects of salt stress (11 dS m^?1) and drought stress (35 % WHC) were investigated for two maize genotypes, focusing on the relation between metabolic changes around the time of pollination and the impact on yield determinants at maturity. The relatively salt‐resistant hybrid Pioneer 3906 and the relatively drought‐resistant hybrid Fabregas were compared. The experiments were conducted in large plastic containers in a vegetation hall in two consecutive years (2011 and 2012). Plant height and leaf area were significantly reduced under both stress conditions. The transpiration rate was only slightly reduced under drought stress; but under salt stress, a significant reduction occurred 40–53 days after sowing. As a significant increase in sucrose concentrations was observed in the salt‐treated maize kernels 2 days after pollination, the availability of assimilates was not limiting and the plants could afford to save water by reduced stomatal opening. Although under both stress conditions the soluble acid invertase activity was reduced 2 days after pollination, concomitantly, an increase in hexose concentrations was observed. Thus, in these experiments, the delivery of hexoses by acid invertase activity did not limit kernel development. Differences in grain yield at maturity between salt and drought stress were most likely caused by salt‐specific effects (Na⁺ toxicity), Fabregas being more affected than Pioneer 3906.     

The effect of water pH on swimming performance in rainbow trout (Salmo gairdneri,Richardson)

A Brett-type respirometer was used to measure the effect of water pH on swimming performance of rainbow trout (Salmo gairdneri). Variations in water pH between 6 and 9 had no measurable effect on maximum aerobic swimming speed. At water pH 4, 5, and 10, however, the critical velocity was only 55, 67, and 61% respectively of that recorded for fish in water of pH 7. Exposure to acid conditions increased coughing and breathing frequency. Acid exposure resulted in a decrease whereas alkaline exposure resulted in an increase in both whole blood and red blood cell pH. Blood gas and acid-base characteristics showed little change during swimming at 2.0 BL/second, but exhaustive swimming resulted in a marked and immediate drop in blood pH in fish in acid, alkaline and neutral water. The blood acid-base status was restored to resting levels after exercise in neutral and alkaline water, but the acidosis was maintained following exercise in acid water. Fatigue occurred earlier and blood lactate levels increased to a higher level in fish swum to exhaustion in acid or alkaline water, compared with fish in neutral water.     

新型化合物唑嘧氯草胺的作用机制

采用培养皿法和常规生化方法,研究了新型除草剂唑嘧氯草胺(暂定名,代号:ZJ-2725)的作用机制。结果显示,同时添加20mg/L浓度的缬氨酸、亮氨酸和异亮氨酸能完全恢复唑嘧氯草胺对苘麻芽的生长抑制作用,而添加相同浓度的单一支链氨基酸只能部分消除其抑制作用。离体条件下,随着唑嘧氯草胺浓度的增大,对乙酰乳酸合成酶(ALS)活性的抑制率增加,ALS活性随反应时间的延长而增加,且两者之间符合Michaelis-Meten方程;活体条件下,唑嘧氯草胺对苘麻的ALS也表现出明显的抑制作用,ALS活性明显下降。表明唑嘧氯草胺在植物体内抑制了3种支链氨基酸的生物合成,进而导致植物蛋白质合成受阻而使植物生长受到抑制,ALS即为唑嘧氯草胺的作用靶标。     

巨胚水稻W025糙米浸水后γ-氨基丁酸含量变化的研究

富含γ-氨基丁酸（GABA）的降血压功能水稻正受到越来越多的关注。W025是通过化学诱变和杂交选育而成的水稻新品系,具有巨胚特征,遗传分析表明巨胚基因受单隐性基因控制。进一步研究W025和其原始品种金南风浸水后γ-氨基丁酸（GABA）含量及其合成关键酶——谷氨酸脱羧酶活性的动态,并用半定量RT-PCR检测了2个谷氨酸脱羧酶转录本在浸水过程的表达变化。结果表明,（1）GABA主要集中在胚部,浸水后W025的GABA积累量显著高于金南风。（2）随着浸水时间延长,谷氨酸脱羧酶（GAD）的活性呈逐渐增加趋势,W025胚部的酶活性显著高于金南风。GAD活性的变化与GABA的积累显著正相关,表明浸水后种胚GABA的积累与谷氨酸脱羧酶的催化反应有关。（3）2个谷氨酸脱羧酶基因OsGAD1与OsGAD2在W025和金南风之间没有转录水平的差异。提示可能存在其它的谷氨酸脱羧酶基因对浸水后GABA的积累起关键作用。     

Rare β-Resorcylic Acid Derivatives from a Halophyte-Associated Fungus Colletotrichum gloeosporioides JS0419 and Their Antifungal Activities

Six new β-resorcylic acid derivatives (1–5 and 7) were isolated from a halophyte-associated fungus, Colletotrichum gloeosporioides JS0419, together with four previously reported β-resorcylic acid lactones (RALs). The relative and absolute stereochemistry of 1 was completely established by a combination of spectroscopic data and chemical reactions. The structures of the isolated compounds were elucidated by analysis of HRMS and NMR data. Notably, compounds 1–3 had a β-resorcylic acid harboring a long unesterified aliphatic side chain, whereas the long aliphatic chains were esterified to form macrolactones in 4–9. Among the isolated compounds, monocillin I and radicicol showed potent antifungal activities against Cryptococcus neoformans, comparable to clinically available antifungal agents and radicicol showed weak antifungal activity against Candida albicans. These findings provide insight into the chemical diversity of fungal RAL-type compounds and their pharmacological potential.     

赤霉酸与杀菌剂处理对蒜薹贮存期品质的影响

研究旨在通过赤霉酸和杀菌剂处理,在降低蒜薹病害发生的同时较好地保持其品质.以金乡蒜薹为研究对象,分别设置赤霉酸GA3 50 mg/L(S2)、赤霉酸GA4+7 50 mg/L(S3)、赤霉酸GA4+7 25 mg/L(S4)、咪鲜胺800倍液(S5)、吡唑醚菌酯1500倍液(S6)、GA4+7 25 mg/L+GA32...     

烟草有机酸研究进展

综述了烟草有机酸的种类及其对烟叶品质的影响,阐述了不同烟草品种、地域、烟叶的组织结构、外源化学物质等对烟叶有机酸含量的影响,并提出了现阶段所存在的问题和对今后研究方向的展望。