植物内整流K~+通道AKT1的研究进展

K~+是植物生长发育所必需的大量营养元素。内整流K~+通道(Arabidopsis K~+transporter 1,AKT1)属于Shaker家族,是介导K~+吸收的重要通道,为质膜的K~+感应器,参与调节细胞的生长发育、调控气孔运动及植物蒸腾作用,能够提高植株的抗旱耐盐性,因而在植物生长过程中具有重要作用。该文概述了AKT1的结构、组织表达定位和表达调控及功能等方面的研究进展,并提出采用蛋白组学、基因工程技术及RNAi手段深入研究K~+、Na~+吸收及转运的协同调控机制,提高作物对土壤中K~+的利用效率及AKT1在植物生理代谢、抗逆性中的作用。     

布鲁氏菌LPS对小鼠巨噬细胞中NLRP3炎症小体转录水平的影响

为研究布鲁氏菌LPS对巨噬细胞中NLRP3炎症小体的影响,本试验提取布鲁氏菌2308、RB51和△WbkA的LPS,以不同浓度与小鼠巨噬细胞相互作用,荧光定量PCR检测其对NLRP3、ASC、Caspase1、IL1-β、IL18转录水平的影响。结果显示RB51LPS和△WbkA LPS上调NLRP3炎症小体相关基因的转录水平,且呈浓度依赖性,而浓度对2308LPS调节NLRP3炎症小体相关基因转录的作用不大;且同一浓度下,RB51LPS和2308LPS比△WbkA LPS更好的调节Caspase1、IL1-β、IL18的转录水平。     

西安蔬菜主产区土壤硝态氮累积现状与蔬菜产品、浅层地下水氮素污染调查研究

以西安郊区主要周边蔬菜产区为研究地点,通过分析蔬菜鲜样、菜田土壤2 m垂直分层土样、浅层地下水的水样,研究蔬菜及菜田生态系统氮肥污染现状.结果表明,按我国的地下水硝酸盐含量标准,在选点采样中1.5～3 m深的地下水硝酸盐含量超标,菜田土层土质疏松与浇水次数较多的菜田硝酸盐向下淋洗现象明显,温室较露地2 m深土层硝态氮与铵态氮分布浓度高,菜田2 m深土层中常有硝态氮与铵态氮的聚集峰,不同深度地下水的菜田韭菜硝酸盐含量差异明显.     

Shikonin inhibits neuronal apoptosis induced by OGD through targeting PI3K/Akt signaling pathway

AIM: To explore the effect of shikonin on rat primary cortical neurons in oxygen-glucose deprivation (OGD)-induced injury model.METHODS: The neurons were pretreated with shikonin at different concentrations (0.02, 0.2, 2 and 20 μmol/L) followed by treatment with OGD. Lactate dehydrogenase (LDH) release assay and fluorescein diacetate/propidium iodide (FDA/PI) double staining were used to detect neuronal viability and apoptosis, and then the optimal concentration of shikonin was determined. LY294002 (PI3K/Akt signaling pathway inhibitor, 1 μmol/L) was added before the addition of shikonin, and the protein level of p-Akt (Ser473) in the neurons was determined by Wes-tern blot. LDH release assay and FDA/PI double staining were also used to detect neuronal viability and apoptosis.RESULTS: A certain concentration (0.2~20 μmol/L) of shikonin increased the viability of impaired neurons (P<0.05) and the protein level of p-Akt (Ser473) in the neurons (P<0.05). The effect of shikonin on neuronal p-Akt (Ser473) levels and the cell death were blocked by LY294002 (P<0.05).CONCLUSION: A certain concentration of shikonin reduces OGD-induced apoptosis of rat primary cortical neurons by activating PI3K/Akt signaling pathway.     

茂兰自然保护区珍稀濒危植物石山木莲的资源现状及保护

石山木莲(Manglietia calcarea X.H.Song)是贵州特有珍稀濒危植物。为了解茂兰保护区石山木莲资源现状,采用样线调查法,对茂兰保护区石山木莲资源分布现状进行调查。结果表明：茂兰保护区石山木莲资源分布狭窄、数量稀少,仅发现8个分布点共计10株,已处于濒危状态。主要分布在保护区洞多、洞常、瑶寨、卡记海拔650~820 m之间的山坳、山腰、洼地、槽谷的次生林中、闲置地边、黔竹林内及密林下。根据石山木莲在茂兰保护区的地理分布特点和资源现状,分析其濒危原因,探讨实现其有效保护的措施。     

Negligible contribution from roots to soil-borne phospholipid fatty acid fungal biomarkers 18:2ω6,9 and 18:1ω9

The phospholipid fatty acid biomarkers 18:1ω9, 18:2ω6,9 and 18:3ω3,6,9 are commonly used as fungal biomarkers in soils. They have, however, also been found to occur in plant tissues, such as roots. Thus, the use of these PLFAs as fungal biomarkers in sieved soil, which may still contain small remains of roots, has been questioned. We used data from a recent beech tree girdling experiment to calculate the contribution of roots to these biomarkers and were able to demonstrate that not more than 0.61% of 18:1ω9 and 18:2ω6,9 in sieved soil samples originated from roots (but 4% of 18:3ω3,6,9). Additionally, the abundance of the biomarker 18:2ω6,9 in the soil was found to be highly correlated to ectomycorrhizal root colonization, which further corroborates its fungal origin. PLFA biomarkers were substantially reduced in vital roots from girdled trees compared to roots of control trees (by up to 76%), indicating that the major part of PLFAs measured in roots may actually originate from ectomycorrhizal fungi growing inside the roots. We calculated, that even a near to 50% reduction in fine root biomass - as observed in the girdling treatment - accounted for only 0.8% of the measured decrease of 18:2ω6,9. Our results demonstrate that both 18:1ω9 and 18:2ω6,9 are suitable biomarkers for detecting fungal dynamics in soils and that especially 18:2ω6,9 is a reliable biomarker to study mycorrhizal dynamics in beech forests.     

桔小实蝇14-3-3基因的克隆和表达谱分析

【目的】克隆桔小实蝇14-3-3蛋白的基因（Bactrocera dorsalis 14-3-3,Bdor 14-3-3）,研究Bdor 14-3-3 mRNA在不同组织和不同发育时期的表达情况,探索其是否参与了桔小实蝇的发育过程。【方法】采用反转录聚合酶链式反应(RT-PCR)和快速扩增cDNA末端(RACE)技术克隆Bdor 14-3-3;采用实时荧光定量PCR（real-time PCR）方法,研究Bdor 14-3-3 mRNA在桔小实蝇不同组织及不同发育时期的相对表达量。【结果】克隆获得了Bdor 14-3-3基因,其编码区长度为747 bp,编码248个氨基酸残基。氨基酸序列一致性分析表明,在昆虫纲中,桔小实蝇与刺舌蝇14-3-3蛋白的序列一致性最高,为98.8%,与豌豆蚜的序列一致性最低,为85.4%。实时荧光定量PCR分析表明,Bdor 14-3-3 mRNA在桔小实蝇不同组织和发育时期都有表达;在雌虫头（去除触角）和翅中的相对表达量均较高,分别是触角的1.39和1.44倍;在雄虫胸和后足中的相对表达量均较高,分别是前足的1.28 和1.23倍。在蛹的早期发育过程中Bdor 14-3-3 mRNA表达量逐渐升高,到7 d蛹期相对表达量达到最高峰,是10 d蛹的4.91倍。【结论】克隆获得了Bdor 14-3-3基因,其表达的14-3-3蛋白可能参与了桔小实蝇的变态发育过程,尤其在蛹的发育过程中Bdor 14-3-3可能发挥着重要作用。     

氮肥后移对土壤氮素供应和冬小麦氮素吸收利用的影响

采用田间试验研究了氮肥后移对土壤氮素供应和冬小麦氮素吸收利用的影响。结果表明,与农民习惯施氮（N 300 kg/hm2,基肥和拔节肥各占1/2）比较,氮肥后移处理（N210kg/hm2,基肥、拔节肥和孕穗肥各占1/3）在不降低小麦产量的同时,大大提高了氮肥利用率,且全生育期氮素表观损失极低。过量施用氮肥(N 300 kg/hm2)明显提高了60 cm以下土层硝态氮含量,增加了其向地下水淋溶迁移的风险。氮肥后移可提高小麦成熟期0-20cm土层硝态氮积累量,降低其在20-100cm土层的积累。基于冬小麦不同生育阶段的氮素吸收量而进行氮肥后移是可行的,氮肥后移可节省氮肥30%,是较为理想的施氮方式。     

温室土壤硝态氮积累的温度、水分、施氮量耦合效应

为了探讨温室作物生产水肥管理和土壤温度对土壤硝态氮累积的影响，本文选取使用5年的温室土壤样品进行培养试验，研究温度、水分、施氮量及其耦合效应对温室土壤硝化作用和硝态氮累积的影响。试验结果表明：温室土壤硝态氮累积量可用“S”曲线进行定量描述，硝化过程中最大硝化速率、延迟期和最大可能累积量是参数土壤温度，含水率和NH₄-N含量的函数；通过正交回归分析得出影响最大硝化速率的因素主次顺序依次为温度、含水率、温度与含水率的交互作用、水肥的耦合作用以及施氮量；影响延迟期的因素主次顺序依次为土壤水分、土壤温度、施氮量以及水肥耦合作用；最大可能累积量与温度、含水率及施氮量呈指数关系，其中施氮量影响最大，土壤温度次之，而这3个因素之间的交互作用对最大可能累积量没有明显的影响。利用回归模型，可为不同温度环境及水肥条件下硝态氮累积量及氮利用的有效性预测提供依据。     

亚洲璃眼蜱唾液腺一新功能基因的克隆与测序

HaB1是亚洲璃眼蜱雌成蜱唾液腺差异表达基因文库中的一个片段,根据其序列设计引物HaB1-GSP1和HaB1-GSP2,以唾液腺总RNA为模板,RACE法扩增获得HaB1的未知3′-末端。测定该末端序列,进行序列拼接,设计全长引物5-′CCAGTCCGAAGGAAGGGCG-3′和5-′TCTC-CGGGCACGTGAAGTGTC-3′。以cDNA第一链为模板,扩增获得基因全长。经核查表明,该基因为一新基因(登录号AY803896)。