温度胁迫下棉花粉蚧热激蛋白基因的表达分析

【目的】为了研究热激蛋白 Hsp70, Hsp70-4和Hsp90在棉花粉蚧Phenacoccus solenopsis抵抗逆温中的作用。【方法】在测序棉花粉蚧转录组的基础上,分析了该虫热激蛋白Hsp70基因家族的2个序列［Pshsp70（GenBank登录号为KJ909505）和Pshsp70-4（GenBank登录号为KJ909506）］和Hsp90基因家族的1个序列,［Pshsp90(GenBank登录号为KJ909507)］,采用实时荧光定量 PCR（RT-qPCR）检测了在不同温度（18和32℃恒温, 37, 39, 41, 43和45℃热激1 h 后26℃恢复1 h)下棉花粉蚧不同发育阶段（2龄若虫、3龄若虫、雌成虫）3种热激蛋白基因的表达量。【结果】Pshsp70 cDNA序列包含1 923 bp的开放阅读框,编码641个氨基酸,理论分子量和等电点分别为70.9 kDa和5.65; Pshsp70-4 cDNA序列包含1 962 bp的开放阅读框,编码654个氨基酸,理论分子量和等电点分别为71.8 kDa和5.38;Pshsp90 cDNA序列包含2 172 bp的开放阅读框,编码724个氨基酸,理论分子量和等电点分别为83.5 kDa和4.93。Pshsp70 和Pshsp70-4均含有Hsp70基因家族高度保守的基序,Pshsp70编码的氨基酸序列与烟粉虱Bemisia tabaci和家蚕Bombyx mori等昆虫的Hsp70 的氨基酸序列一致性为 85%;Pshsp70-4编码的氨基酸序列与白蜡蚧Ericerus pela和点蜂缘蝽Riptortus pedestris等昆虫的Hsp70的氨基酸序列一致性高达95%;Pshsp90也含有Hsp90基因家族高度保守的基序,Pshsp90编码的氨基酸序列与赤拟谷盗Tribolium castaneum和东亚小花蝽Orius sauteri等昆虫的Hsp90 的氨基酸序列一致性为 87%。热激蛋白基因表达量分析结果表明,在18℃恒温条件下,粉蚧2龄若虫的3个PsHsps基因的mRNA相对表达量均比对照(26℃)低,在32℃恒温条件下,各龄期的Hsp70基因的相对表达量均显著高于对照。在37~45℃下热激1 h并在26℃下恢复1 h,棉花粉蚧3个龄期的3个热激蛋白PsHsps基因的相对表达量随温度的升高总体呈增加趋势,相关性分析表明,除Pshsp70-4在雌成虫中的表达量与热胁迫温度的相关系数为0.225外,各龄期中3个基因的表达量与温度的相关系数均大于0.6,显著相关;43℃和45℃胁迫下,各龄期的3个热激蛋白基因相对表达量均显著高于对照组（P<0.05）。【结论】棉花粉蚧热激蛋白基因的表达与温度呈正相关,在该虫应对高温中起着重要作用。     

Effects of changes in discharge level on temperature and oxygen regimes in a new reservoir and downstream

Temperature and oxygen regimes were monitored weekly in a four-year old reservoir and downstream for ten weeks during the summer (May 15 to July 30, 1979), and monthly in the fall and winter. During the summer discharge levels were changed from top to bottom in the eighth week, back to top in the ninth, all at 0.71 m³/s (= 25 cfs), and returned to the bottom in the tenth, but at 1.14 m³/s (= 40 cfs). Changing the discharge level had little or no impact on the thermal regime within the lake or downstream at 1.14 m³/s and only a moderate impact on water in the lake near the dam at 0.71 m³/s bottom discharge by generating double thermoclines. Oxygen depletion rates were greatest near the surface of the lake, mainly due to temperature effects, but increased greatly at the 3 m depth, the level of the top discharge port, when discharge was changed from bottom to top. Discharge of anoxic waters through the bottom of the dam caused a drop in oxygen content immediately downstream but oxygen content returned to inflow values within 1 km downstream of the dam.     

中国仓鼠卵巢细胞表达新技术

中国仓鼠卵巢细胞（CHO细胞）是基因工程药物生产的最佳表达系统之一,在生物制药中被广泛应用。传统的获得高表达CHO细胞株的方法费时、费力。近年来出现了一些CHO细胞高效表达新技术,它们从克服位置效应,提高基因转录效率、mRNA翻译效率及稳定性、筛选高表达细胞的效率等不同层次调控外源基因在CHO细胞中的高效表达。与MTX加压扩增基因获得高效表达外源基因的方法比较,能够节约时间、减少工作量,不易丢失高表达细胞株。     

不同蛋白质水平的饵料对黄喉拟水龟生长影响的研究

依据单因子梯度设计原理,采用进口鱼粉、豆粕为主要蛋白源制成蛋白质含量分别为50.2%、47.3%、44.3%和41.4%共4种试验饵料,研究不同蛋白质水平饵料对黄喉拟水龟生长的影响.结果 表明,经过120 d对80只黄喉拟水龟幼龟的饲养,当饵料的蛋白质含量为47.3%时,黄喉拟水龟的生长速度最快,均显著高于其他3个组(P<0.05);蛋白质效率最高,极显著高于50.2%组(P<0.01),也分别显著高于44.3%组和41.4%组(P<0.05);耗料增重比最低,分别极显著低于44.3%组和50.2%组(P<0.01),也显著低于41.4%组(P<0.05).但不同蛋白质水平的饵料对黄喉拟水龟龟体蛋白质含量没有明显的影响(P>0.05).     

The mechanism of myoblast deformation in response to cyclic strain - A cytomechanical study

Mechanical strain is one of the important epigenetic factors that cause deformation and differentiation of skeletal muscles. This research was designed to investigate how myoblast deformation occurs after cyclic strain loading. Myoblasts were passaged three times and harvested; various cyclic strains (2.5kPa, 5kPa and 10kPa) were then loaded using a pulsatile mechanical system. The adaptive response of the myoblasts was observed at different time points (0.5h, 1h, 6h and 12h) post-loading. At the early stage of cyclic strain loading (<1h), almost no visible morphological changes were observed in the myoblasts. The actin cytoskeleton showed a disordered arrangement and a weak fluorescence expression; there was little expression of talin. At 6h and 12h post-loading, the myoblasts changed their orientation to parallel (in the 2.5kPa and 5kPa groups) or perpendicular (in the 10kPa group) to the direction of strain. Fluorescence expression of both the actin cytoskeleton and talin was significantly increased. The results suggest that cyclic strain has at least two ways to regulate adaptation of myoblasts: (1) by directly affecting actin cytoskeleton at an early stage post-loading to cause depolymerization; and (2) by later chemical signals transmitted from the extracellular side to intracellular side to initiate repolymerization.     

草地农业生态系统的碳平衡分析方法

根据草地农业生态系统的结构,它的碳平衡为4个生产层的碳平衡之和,也是3个界面的碳平衡之和,而某一生产层或者某一界面的碳平衡则是其固定、输入、排放和输出的碳之和。草地农业生态系统4个生产层的碳平衡分析方法定量重要生产环节的碳汇与碳源过程,便于草业生产改进碳汇管理;草地农业生态系统3个界面的碳平衡分析方法显示碳源和碳汇的发生机理,及其空间和数量关系,便于调控草业生产组分以增汇减排;但是,这两个方法不易区分碳的来源和去向,难以明确其利用效率。草地农业生态系统碳平衡分析的输入/输出法定量地指示碳的来源和去向,以及碳效率,计算简单,但是较为概括,不利于牧场尺度的草业碳汇管理。以中国祁连山甘肃马鹿牧场和澳大利亚塔斯玛尼亚奶牛牧场为例,用3种方法分析了两个牧场的碳平衡,结果表明,放牧管理的草业系统的主要碳源是休闲旅游、产品加工流通环节产生的温室气体,主要碳汇是草地和土壤中贮存的碳,好的草地管理可以增汇减排。     

同水塘分布两种无尾两栖类蝌蚪的竞争策略

实验室条件下,通过活动性水平,变态时的体重、增长率和完成变态所需时间考察同水塘分布的中华蟾蜍(Bufo gargarizans)和高原林蛙蝌蚪(Rana kukunoris)的竞争策略。实验按照2×3因子设计,即:食物资源2个水平(高、低),组合方式3个水平(10只中华蟾蜍蝌蚪,记为B组;5只中华蟾蜍蝌蚪和5只高原林蛙蝌蚪,记为BR组;10只高原林蛙蝌蚪,记为R组)。中华蟾蜍蝌蚪的活动性在食物水平低时显著低于食物水平高时,而高原林蛙蝌蚪的活动性在不同食物水平下无显著差异;食物水平低时,混合组的高原林蛙蝌蚪变态时体重和体重增长率都显著高于R组,而混合组中华蟾蜍蝌蚪与B组相比无显著差异;在不同处理组中,食物水平低时混合组中华蟾蜍蝌蚪幼体期最短。这些结果表明:中华蟾蜍蝌蚪在不同食物资源条件下所选择的生存策略可能不同,即食物资源充足时,增加活动性获取更多食物;食物资源有限时,降低活动性且提前完成变态;与中华蟾蜍蝌蚪相比,在食物资源有限时高原林蛙蝌蚪获取食物能力更强。     

间作对氮调控玉米光合速率和光合氮利用效率的影响

研究间作后作物光合碳同化和光合氮利用效率(PNUE)对氮投入的响应, 对阐释间作产量优势的氮调控效应, 指导间作氮肥管理有重要意义。本研究设置玉米(Zea mays)单作、玉米间作两种种植模式的4个氮水平(N0, 0 kg·hm ^-2; N1, 125 kg·hm ^-2; N2, 250 kg·hm ^-2; N3, 375 kg·hm ^-2), 分析间作与施氮量对玉米叶片特征、光合参数、PNUE和产量的影响。结果表明: 与单作相比, 间作显著增加玉米叶片的叶干质量和比叶质量; 各施氮水平(除N3)下, 间作中靠近马铃薯(Solanum tuberosum)侧的玉米叶面积均显著高于单作玉米。单间作对比发现, 间作提高了玉米光饱和点和暗呼吸速率。单作、间作靠玉米侧(I-M)、间作靠马铃薯侧(I-P)的玉米PNUE均随施氮量增加而降低, 降幅以I-P最大; 施氮量低于250 kg·hm ^-2时, 相同施氮量下的玉米PNUE和净光合速率(P_n)均以I-P最高, I-M和单作次之。间作显著提高了玉米产量(土地当量比>1)。该研究中当施氮量≤250 kg·hm ^-2时, 间作I-P的玉米叶片P_n和PNUE显著提高可能是间作玉米产量提高的重要原因。     

Multiple Neurite Formation in Neuroblastoma Cell Lines by Griseolic Acid, a Potent Inhibitor of Cyclic Nucleotide Phosphodiesterases

The morphological change of several neuroblastoma cell lines induced by griseolic acid, a novel and potent inhibitor of cyclic nucleotide phosphodiesterase (PDE), was examined. In the cell lines tested, Neuro-2a (a murine neuroblastoma cell line) showed dose-dependent (1 microM-1 mM) neurite extension. Griseolic acid markedly increased the intracellular cyclic AMP level of Neuro-2a cells, suppressed DNA synthesis (82% at 1 mM), and induced multipolar (multiple-neurite-bearing)-type neuritogenesis. A similar type of neurite outgrowth was induced by 8-bromo-cyclic AMP, which also elevated the intracellular cyclic AMP concentration. In contrast, when Neuro-2a cells were treated with retinoic acid, neurite formation was of the monopolar (single-neurite-bearing) type. Papaverine and theophylline, which have been frequently used as PDE inhibitors, failed to induce these morphological changes up to 1 mM, probably owing to the lesser potency of these compounds as compared with griseolic acid on the inhibition of PDE. Retinoic acid, theophylline, and papaverine were ineffective at elevating the intracellular cyclic AMP level. These results suggest that multipolar-type cell shape change in Neuro-2a cells is correlated with the accumulation of intracellular cyclic AMP and that griseolic acid is a useful compound to induce neuroblastoma cells into terminal differentiation.