厚壳贻贝whirlin类贝壳基质蛋白的重组表达与功能分析

贝壳历来是生物工程和材料学研究的重要对象。贝壳中的贝壳基质蛋白质在贝壳的形成与发育过程中具有重要的调控作用。Whirlin类蛋白质(Whirlin-like protein,WLP)是一种从厚壳贻贝(Mytilus coruscus)中鉴定的新型贝壳基质蛋白质。序列分析结果显示,该蛋白质含有PDZ(postsynaptic density/Discs large/Zonula occludens)结构域,而该结构域对贝壳生物矿化的影响目前尚无报道。为深入了解WLP在贝壳形成中对碳酸钙晶体的影响,在序列分析基础上,采用密码子优化结合原核重组表达,获得其重组表达产物后,开展了重组WLP对碳酸钙晶体形貌及晶型的影响研究,结晶速度抑制以及碳酸钙晶体结合分析。分析结果表明,重组WLP能诱导文石型碳酸钙晶体的形貌和方解石型碳酸钙晶体的晶型发生改变;同时重组WLP对碳酸钙晶体具有结合作用,且能抑制碳酸钙晶体的结晶速度。上述结果表明,WLP对贝壳的形成及发育具有重要影响,并可能在贝壳肌棱柱层的形成中发挥了重要作用。     

广西防城港黑翅长脚鹬的繁殖行为

本研究于2021年3～9月,采用目标观察和全事件记录法,对广西防城港市钦州湾八路水湿地黑翅长脚鹬（Himantopus himantopus）的繁殖习性进行全过程观察记录。黑翅长脚鹬的栖息生境主要在盐田、虾塘和鱼塘,而巢主要分布在盐田生境。共发现39巢,雌雄共同营巢,按照主要巢材将其巢分为干草巢、碎石巢、泥皮巢和牛毛毡草巢4种;巢材包括禾本科（Gramineae）和莎草科（Cyperaceae）植物以及碎石、贝壳等;巢外径为（23.3±10.7）cm,巢内径为（11.2±1.9）cm,巢深为（1.6±0.5）cm,巢高为（6.5±4.3）cm(n=39);筑巢需（3±2）d(n=6)。窝卵数2～4枚,1～2 d产1枚卵,7 d内产完满窝卵（n=6）。雌雄均参与孵卵,雄性孵卵时间比雌性长,但二者差异不显著（P> 0.05）,雄性（8 550±245.9）min,雌性（7 530±263.3）min,孵卵期为（25±2）d(n=6)。育雏期（26±3）d(n=6),雌雄轮流育雏,育雏前、中期（雏鸟1～20d日龄）,雌性育雏时间比雄性长,是雄性的2倍,育雏后期（雏鸟大于20 d日龄）,...     

Mutations in the regulatory subunit of yeast acetohydroxyacid synthase affect its activation by MgATP

Isoleucine, leucine and valine are synthesized via a common pathway in which the first reaction is catalysed by AHAS (acetohydroxyacid synthase; EC 2.2.1.6). This heterotetrameric enzyme is composed of a larger subunit that contains the catalytic machinery and a smaller subunit that plays a regulatory role. The RSU (regulatory subunit) enhances the activity of the CSU (catalytic subunit) and mediates end-product inhibition by one or more of the branched-chain amino acids, usually valine. Fungal AHAS differs from that in other organisms in that the inhibition by valine is reversed by MgATP. The fungal AHAS RSU also differs from that in other organisms in that it contains a sequence insert. We suggest that this insert may form the MgATP-binding site and we have tested this hypothesis by mutating ten highly conserved amino acid residues of the yeast AHAS RSU. The modified subunits were tested for their ability to activate the yeast AHAS CSU, to confer sensitivity to valine inhibition and to mediate reversal of the inhibition by MgATP. All but one of the mutations resulted in substantial changes in the properties of the RSU. Unexpectedly, four of them gave a protein that required MgATP in order for strong stimulation of the CSU and valine inhibition to be observed. A model to explain this result is proposed. Five of the mutations abolished MgATP activation and are suggested to constitute the binding site for this modulator.     

HCMV IE2-mediated inhibition of HAT activity downregulates p53 function

Targeting of cellular histone acetyltransferases (HATs) by viral proteins is important in the development of virus-associated diseases. The immediate-early 2 protein (IE2) of human cytomegalovirus (HCMV) binds to the tumor suppressor, p53, and inactivates its functions by unknown mechanisms. Here, we show that IE2 binds to the HAT domain of the p53 coactivators, p300 and CREB-binding protein (CBP), and blocks their acetyltransferase activity on both histones and p53. The minimal HAT inactivation region on IE2 involves the N-terminal 98 amino acids. The in vivo DNA binding of p53 and local histone acetylation on p53-dependent promoters are all reduced by IE2, but not by mutant IE2 proteins that lack the HAT inhibition region. Furthermore, the p53 acetylation site mutant, K320/373/382R, retains both DNA binding and promoter transactivation activity in vivo and these effects are repressed by IE2 as well. Together with the finding that only wild-type IE2 exerts an antiapoptotic effect, our results suggest that HCMV IE2 downregulates p53-dependent gene activation by inhibiting p300/CBP-mediated local histone acetylation and that IE2 may have oncogenic activity.     

浙江分水江水库大型底栖动物群落结构及水质评价

2008年11月-2009年10月,在浙江桐庐分水江水库设置7个站点对大型底栖动物进行逐月调查.结果表明:调查共采集到37种底栖动物,主要由寡毛纲和摇蚊科物种组成.春、夏、秋季优势种均为霍甫水丝蚓,冬季优势种为羽摇蚊.直接收集者在物种数量、密度和生物量上均占绝对优势.群落年均密度和年均生物量分别为(488.0±48.8) ind·m-2和(1.86±0.49) g·m-2.底栖动物密度在站点间无明显差异但存在显著的季节变化,呈现春季＞夏季＞冬季＞秋季的趋势,生物量在站点、季节间均无显著差异.水温和水深是影响底栖动物时空分布的主要因子.Shannon多样性指数和Goodnight-Whitley指数不适合用于该水库的水质评价,其他指数综合显示分水江水库属于轻度污染.     

三种植物源药剂对红火蚁的防治效果评估及其对本地蚂蚁群落影响

红火蚁Solenopsis invicta Buren是一种危险性入侵害虫,可对人类健康、农林业生产、公共安全和生态系统产生严重的负面影响。目前,化学农药是防治红火蚁的主要方法。然而,大多数化学农药并不适用于有机农场、水产养殖区等生态敏感区。为筛选出用于生态敏感区红火蚁防治的药剂,本文结合室内和田间试验评估了植物源杀虫剂苦参碱Matrine、鱼藤酮Rotenone和除虫菊素Pyrethrin对红火蚁的防治效果。室内试验结果表明,苦参碱、鱼藤酮和除虫菊素对红火蚁均具有较高的毒性。田间试验表明,25.00 mg/L和12.50 mg/L苦参碱、250.00 mg/L 和125 mg/L鱼藤酮、75.00 mg/L和37.50 mg/L除虫菊素灌巢处理,红火蚁蚁巢减退率分别达到100%、81.25%、87.50%、79.17%、71.73%和66.67%。然而,除25.00 mg/L苦参碱外,其他处理均导致在被灌巢的蚁巢周围短期内出现新蚁巢。灌巢处理后,处理区的蚂蚁多样性指数和均匀度指数升高,优势度指数下降。综上所述,苦参碱、鱼藤酮和除虫菊素适合灌巢处理防治红火蚁,其中0.5%苦参碱可溶性液剂能有效降低红火蚁种群数量,使得蚁巢减退率达100%,同时对本地蚂蚁群落没有负面影响,因此该商品制剂在红火蚁防治方面具有较好的开发潜力。     

赛黑桦不同半同胞家系种子活力比较

种子活力能够预测幼苗的生长势和适应性,可作为评价采种母树的重要指标。赛黑桦作为东北林区木质坚硬的树种之一,关于其种子活力研究尚未见报道。比较不同家系赛黑桦种子活力,对赛黑桦采种母树进行初步评价,可为赛黑桦优良家系的选择提供参考。本研究以赛黑桦蛟河、集安和珲春3个采种地共30个半同胞家系为试材,对采种地及家系间种子千粒重、发芽率、发芽势、发芽指数、活力指数、出苗率和幼苗健壮率等7个性状进行了方差分析、遗传力估算、多重比较、相关性分析,并利用主成分分析法对参试家系进行了综合评价。结果表明,赛黑桦种子活力指数和幼苗健壮率在不同采种地间的差异达到了显著或极显著水平;7个性状在不同家系间的差异均达到显著或极显著水平;除出苗率和幼苗健壮率外,各性状的家系遗传力均高于0.68;7个性状间均呈现显著或极显著的正相关;采用主成分分析法选择JH6、JA1、JA7、JH10、JH3、HC1和HC10等7个家系为优良家系,这些家系的种子千粒重、发芽率、发芽势、发芽指数、活力指数、出苗率和幼苗健壮率的平均值分别比总平均值高3.87%、30.29%、30.22%、31.99%、58.22%、11.88%和30.60%。初步认为这些优良家系的母树是赛黑桦采种的首选母树。     

类受体蛋白激酶与植物非生物胁迫应答

类受体蛋白激酶(receptor-like protein kinase,RLK)是植物信号转导网络中的重要成员,参与介导生长、发育以及逆境胁迫应答等多种细胞代谢过程．在植物细胞中已发现和克隆了富含亮氨酸重复区型(LRR)、凝集素型(lectin-like)和细胞壁相联型(WAK)等不同的RLK亚家族．这些RLK能够感受多种发育和外界环境胁迫信号, 并在植物对非生物胁迫的响应过程中发挥重要的调控作用．本文结合当今国内外研究进展,简述植物RLK的典型结构域特征,详细介绍多种RLK在植物逆境信号识别与转导中发挥的作用,同时对RLK在非生物胁迫应答中的具体作用机制进行了探讨．     

人源FGF-21在脂肪细胞糖代谢中的作用

近年来研究发现,成纤维细胞生长因子(FGF)-21是一种新的代谢调节因子.为了深入研究人源FGF-21（hFGF-21）的生物活性,本实验利用SUMO高效表达载体,高效表达成熟的hFGF-21,并利用小鼠3T3-L1脂肪细胞检测hFGF-21的糖代谢活性．实验结果表明,hFGF-21可促进脂肪细胞的葡萄糖吸收,且葡萄糖吸收效率呈剂量依赖性．hFGF-21作用4 h即可促进脂肪细胞糖吸收,其活性可持续24 h以上．hFGF-21与胰岛素共同作用的葡萄糖吸收效果,明显优于它们的单独作用结果,说明hFGF-21与胰岛素发挥协同作用．脂肪细胞经hFGF-21预处理后,显著增加了胰岛素促进脂肪细胞吸收葡萄糖的效率,说明hFGF-21可以增加胰岛素的敏感性．本实验为临床应用hFGF-21治疗糖尿病,增加胰岛素敏感性提供了依据．     

The circadian regulation of extracellular ATP

Extracellular ATP is a potent signaling molecule released from various cells throughout the body and is intimately involved in the pathophysiological functions of the nervous system and immune system by activating P2 purinergic receptors. Recent increasingly studies showed that extracellular ATP exhibits circadian oscillation with an approximately 24-h periodicity, which participates in regulatory pathways of central oscillator suprachiasmatic nucleus and peripheral oscillator bladder, respectively. Oscillators modulate the protein expression of ATP release channels and ectonucleotidase activity through clock genes; indeed, real-time alterations of ATP release and degradation determine outcomes of temporal character on extracellular ATP rhythm. The regulatory pathways on extracellular ATP rhythm are different in central and peripheral systems. In this review, we summarize the circadian rhythm of extracellular ATP and discuss several circadian regulatory pathways in different organs via ATP release and degradation, to provide a new understanding for purinergic signaling in the regulatory mechanism of circadian rhythm and a potential target to research the circadian regulation of extracellular ATP in other circadian oscillators.