龙须藤叶粗提物的分离纯化及生物活性初探

为进一步研究和开发新植物源农药,拓宽龙须藤(Bauhinia championii)的生物活性研究,探索其不同组分潜在的杀菌和除草活性,该研究通过常温冷浸提取法提取、真空浓缩得到甲醇提取物。结果表明:用硅胶柱层析分离纯化,经TLC检识和碘缸显色后整合得到9个组分。反复重结晶7号和8号组分中析出的物质,经TLC检识和测熔点,得到1个纯化合物,编为33号,经波谱数据分析与molbase库对照,鉴定该化合物为(1R,2S,3S,4S,5S,6S)-6-甲氧基-1,2,3,4,5-环己烷五醇,是一种重要的工业原料。杀菌和除草活性试验结果显示,粗提物在1 000μg·m L~(-1)时对水稻稻瘟病菌的抑制率为(40.84±1.00)%,对稗草根的抑制率为(49.18±2.33)%;各组分在500μg·m L~(-1)时,4号组分对水稻稻瘟病菌的抑制率达到(44.19±0.76)%,2号和3号组分对稗草根的抑制率分别为(88.92±1.31)%和(90.99±1.45)%,3号和6号组分对马齿苋根的抑制率分别为(72.06±1.31)%和(89.92±1.73)%。这表明龙须藤叶提取物对水稻稻瘟病菌、稗草根和马齿苋根有良好的抑制效果,可进一步分离2号、3号、4号、6号组分,以获得高活性的单体化合物。     

Perinatal nutrition interacts with genetic background to alter behavior in a parent‐of‐origin‐dependent manner in adult Collaborative Cross mice

Previous studies in animal models and humans have shown that exposure to nutritional deficiencies in the perinatal period increases the risk of psychiatric disease. Less well understood is how such effects are modulated by the combination of genetic background and parent‐of‐origin (PO). To explore this, we exposed female mice from 20 Collaborative Cross (CC) strains to protein deficient, vitamin D deficient, methyl donor enriched or standard diet during the perinatal period. These CC females were then crossed to a male from a different CC strain to produce reciprocal F1 hybrid females comprising 10 distinct genetic backgrounds. The adult F1 females were then tested in the open field, light/dark, stress‐induced hyperthermia, forced swim and restraint stress assays. Our experimental design allowed us to estimate effects of genetic background, perinatal diet, PO and their interactions on behavior. Genetic background significantly affected all assessed phenotypes. Perinatal diet exposure interacted with genetic background to affect body weight, basal body temperature, anxiety‐like behavior and stress response. In 8 of 9 genetic backgrounds, PO effects were observed on multiple phenotypes. Additionally, we identified a small number of diet‐by‐PO effects on body weight, stress response, anxiety‐ and depressive‐like behavior. Our data show that rodent behaviors that model psychiatric disorders are affected by genetic background, PO and perinatal diet, as well as interactions among these factors.     

Bipyridylium quaternary salts and related compounds. V. Pulse radiolysis studies of the reaction of paraquat radical with oxygen. Implications for the mode of action of bipyridyl herbicides

1. Rate constants for reduction of paraquat ion (1,1′-dimethyl-4,4′-bipyridy-lium, PQ²⁺) to paraquat radical (PQ⁺·) by e⁻_aq and CO₂⁻· have been measured by pulse radiolysis. Reduction by e⁻_aq is diffusion controlled (k = 8.4·10¹⁰ M⁻¹·s⁻¹) and reduction by CO₂⁻· is also very fast k = 1.5·10¹⁰ M⁻¹·s⁻¹).

2. The reaction of paraquat radical with oxygen has been analysed to give rate constants of 7.7·10⁸ M⁻¹·s⁻¹ and 6.5·10⁸ M⁻¹·s⁻¹ for the reactions of paraquat radical with O₂ and O₂⁻·, respectively. The similarity in these rate constants is in marked contrast to the difference in redox potentials of O₂ and O₂⁻· (− 0.59 V and + 1.12 V, respectively).

3. These rate constants, together with that for the self-reaction of O₂⁻·, have been used to calculate the steady-state concentration of O₂⁻· under conditions thought to apply at the site of reduction of paraquat in the plant cell. On the basis of these calculations the decay of O₂⁻· appears to be governed almost entirely by its self-reaction, and the concentration 5 μm away from the thylakoid is still 90% of that at the thylakoid itself. Thus, O₂⁻· persists long enough to diffuse as far as the chloroplast envelope and tonoplast, which are the first structures to be damaged by paraquat treatment. O₂⁻· is therefore sufficiently long-lived to be a candidate for the phytotoxic product formed by paraquat in plants.     

吡咯喹啉醌合成及生产工艺研究进展

吡咯喹啉醌(pyrroloquinoline quinone, PQQ)是继烟酰胺和核黄素之后发现的第三类氧化还原酶辅因子,普遍存在于生物体中参与呼吸链电子传递,具有促进线粒体产生、清除自由基、增强细胞代谢和预防心肌损伤等生理功能,在医药、食品和农业领域具有广泛的应用前景。微生物发酵法是PQQ生产的主要方式,解析PQQ生物合成途径及其调控机制,通过代谢工程选育短周期、高产量的生产菌是PQQ工业化的研究方向之一。本文综述了PQQ的合成途径、高产菌株选育以及微生物发酵生产与分离纯化的研发工作,为深入阐释PQQ的生物合成机制和工业化生产菌株的选育提供参考。     

Screening and identification of a microsatellite marker associated with sex in Wami tilapia, <Emphasis Type="Italic">Oreochromis urolepis hornorum</Emphasis>

In this study, primer pairs of 15 microsatellite markers associated with sex determination of tilapia were selected and amplified in Wami tilapia, Oreochromis urolepis hornorum. While one marker, UNH168, on linkage group 3 (LG3) was associated (P < 0.001) with the phenotypic sex in the experimental population, nine genotypes were detected in both sexes. Only 99-bp allele was detected in the female samples, while 141, 149 and 157-bp alleles were present in both male and female samples. UNH168 was localized by fluorescence in situ hybridization (FISH) on the long arm of the largest tilapia chromosome pair (chromosome 1, equivalent to LG3). This sex-linked microsatellite marker could potentially be used for marker-assisted selection in tilapia breeding programmes to produce monosex male tilapia.     

NaCl胁迫对甘薯叶片叶绿体超微结构及一些酶活性的影响

随ＮａＣｌ 胁迫浓度的提高,甘薯叶片叶绿体数目逐渐减少, 类囊体膜片层松散、扭曲、破裂并逐渐解体, 叶绿素含量下降。与此同时,Ｈ２Ｏ２ 、ＭＤＡ 含量增加, ＡＳＰ、ＳＯＤ 活性表现出先上升后下降的趋势。耐盐品种在ＮａＣｌ 胁迫下能维持较强的Ｈ２Ｏ２ 清除能力和较低的ＭＤＡ 水平