Preliminary investigation of sequence-independent DNA binding proteins in rat skeletal muscle sarcoplasmic reticulum and their function

To observe the binding of plasmid DNA to non-nuclear DNA binding proteins in sarcoplasmic reticulum (SR) and the effects of this binding on SR function, sarcoplasmic reticulum proteins in rat skeletal muscle were isolated by differential centrifuge and sucrose density-gradient centrifuge. The results showed that there are two sequence-independent DNA binding proteins in SR proteins, the molecular weights of which are 83 and 58 ku, respectively. Ca²⁺ uptake and release of SR were remarkably promoted by the binding of plasmid DNA to DNA binding proteins in SR, the mechanism is probably through increasing of Ca²⁺-ATPase activity in SR and changing of character of Ca²⁺ release channel ryanodine receptors induced by the binding. These results suggest that there exist DNA binding proteins in SR and its binding to DNA may affect Ca²⁺ transport of SR.     

槟榔胚培养

1植物名称槟榔(Areca catechu L.)。2材料类别幼胚。3培养条件(1)启动培养基:MS 5%(V/V)椰子水 40g·L-1蔗糖 1g·L-1活性碳 0.55%琼脂;(2)生长培养基:MS BA1mg·L-1(单位下同) NAA0.5 5%(V/V)椰子水 4     

瘢痕疙瘩中TIEG1的高表达

转化生长因子-β1(TGF-β1/Smads)信号转导通路的持续激活是瘢痕疙瘩形成的重要机制.研究发现这条通路重要的负反馈调节信号分子Smad7表达明显下调,Smad2/3的磷酸化水平和蛋白质量并无明显改变.但是,Smad7下调的机制尚不清楚.采用生物信息学方法对Smad7的启动子进行分析;用RT-PCR和蛋白质印迹分别检测了正常皮肤、正常瘢痕及瘢痕疙瘩组织中的Sp1样转录因子TIEG1mRNA及蛋白质的表达水平;体外培养正常皮肤、正常瘢痕及瘢痕疙瘩成纤维细胞,检测TIEG1 mRNA及蛋白的表达水平.研究结果显示,Smad7启动子上有Sp1的位点,TIEG1 mRNA及蛋白质水平在瘢痕疙瘩组织及瘢痕疙瘩成纤维细胞中表达明显高于正常瘢痕和正常皮肤(P<0.05).说明瘢痕疙瘩中TIEG1可能是Smad7下调的重要原因,有必要进一步研究TIEG1对Smad7的调控作用机制.     

CD72几种新的剪切形式的发现及它们在红斑狼疮模型鼠中的差异表达

CD72是一个重要的B细胞特异性受体,它以多种选择性剪切形式存在.在小鼠脾细胞中发现并鉴定了8种新的CD72选择性剪切形式,这些剪切形式中包含有2种独特的插入片段,一种选择性剪切保留了一个内含子(intron1),而这个内含子被翻译成氨基酸序列后并没有改变前后外显子的读码框,另一种使用了一个位于内含子之内的3′剪切位点,从而产生移码,提前终止了蛋白质的开放读码框,称为3′AS(3′alternative splicingsite).比较了CD72所有剪切形式在BALB/C小鼠和NZB/W小鼠中的差异表达,发现:a.含有3′AS的剪切形式的表达都很少;b.WT, In1, In1-Ex3和-Ex3的表达在BLAB/C小鼠中比在NZB/W小鼠中高;c.没有ITIM2的-Ex2-Ex3剪切形式在NZB/W小鼠中有特异性高表达.这些结果提示,CD72的多种选择性剪切形式在调控B细胞受体信号转导过程中可能发挥着不同的作用,并与系统性红斑狼疮的发病密切相关.     

The breeding of two polyploid rice lines with the characteristic of polyploid meiosis stability

Polyploidization is a basic feature of plant evolution. Nearly all of the main food, cotton and oil crops are polyploid. When ploidy levels increase, yields double; this phenomenon suggested a new strategy of rice breeding that utilizes wide crosses and polyploidization dual advantages to breed super rice.Because low seed set rates in polyploid rice usually makes it difficult to breed, the selection of Ph-liked gene lines was emphasized. After progenies of indica-japonica were identified and selected, two polyploid lines, PMeS-1 and PMeS-2 with Polyploid Meiosis Stability (PMeS) genes were bred. The procedure included seven steps: selecting parents, crossing or multiple crossing, back-crossing, doubling chromosomes, identifying the polyploid, and choosing plants with high seed set rates that can breed themselves into stable lines. The characteristics of PMeS were determined by observing meiotic behaviors and by cross-identification of seed sets. PMeS-1 and PMeS-2, (japonica rice), have several characteristics different from other polyploid rice lines, including a higher rate of seed set (more than 65%, increasing to more than 70% in their F1 offspring); and stable meiotic behaviors (pairing with bivalents and quarivalents nearly without over-quarivalent in prophase, nearly without lagging chromosomes in metaphase and without micronuclei in anaphase and telophase). The latter was obviously different from control polyploid line Dure-4X, which displayed abnormal meiotic behaviors including a higher rate of multivalents, univalents and trivalents in prophase, lagging chromosomes in metaphase and micronuclei in anaphase and telophase. There were also three differences of the breeding method between PMeS lines and normal diploid lines: chromosomes doubling, polyploidism identifying and higher seed set testing. The selection of PMeS lines is the first step in polyploid rice breeding; their use will advance the progress of polyploid rice breeding, which will in turn offer a new way to breed super rice.     

载脂蛋白A-Ⅰ通过PKA信号途径影响ABCA1的表达与功能

以THP-1巨噬细胞源性泡沫细胞为研究对象,观察载脂蛋白A-Ⅰ与三磷酸腺苷结合盒转运体A1(ATP binding cassette transporter A1,ABCA1)的相互作用,并探讨它们相互作用的机制,以便了解载脂蛋白A-Ⅰ和ABCA1在动脉粥样硬化发生发展中的作用.THP-1巨噬细胞源性泡沫细胞经各种因素处理后,采用油红“O”染色,观察细胞内的脂滴,运用液体闪烁计数器检测细胞内胆固醇流出,高效液相色谱分析细胞内总胆固醇、游离胆固醇和胆固醇酯含量,用逆转录-聚合酶链反应和蛋白质印迹分析法分别检测ABCA1 mRNA与ABCA1蛋白质的水平.实验结果显示,载脂蛋白A-Ⅰ和腺苷酸环化酶激动剂Forskolin(FRK)引起THP-1巨噬细胞源性泡沫细胞总胆固醇、游离胆固醇与胆固醇酯减少,而腺苷酸环化酶抑制剂SQ-22536引起THP-1巨噬细胞源性泡沫细胞总胆固醇、游离胆固醇与胆固醇酯增加.载脂蛋白A-Ⅰ引起THP-1巨噬细胞源性泡沫细胞ABCA1蛋白质水平和细胞内胆固醇流出增加.FRK引起THP-1巨噬细胞源性泡沫细胞ABCA1蛋白质水平和细胞内胆固醇流出呈时间和浓度依赖性增加.SQ-22536引起THP-1巨噬细胞源性泡沫细胞ABCA1蛋白质水平和细胞内胆固醇流出减少.结果提示,载脂蛋白A-Ⅰ可提高THP-1巨噬细胞源性泡沫细胞ABCA1蛋白质水平,增加细胞内胆固醇流出,降低细胞内胆固醇聚积.其机制可能是通过PKA信号途经使细胞ABCA1蛋白质水平增加.     

CO2 balance of boreal, temperate, and tropical forests derived from a global database

Terrestrial ecosystems sequester 2.1 Pg of atmospheric carbon annually. A large amount of the terrestrial sink is realized by forests. However, considerable uncertainties remain regarding the fate of this carbon over both short and long timescales. Relevant data to address these uncertainties are being collected at many sites around the world, but syntheses of these data are still sparse. To facilitate future synthesis activities, we have assembled a comprehensive global database for forest ecosystems, which includes carbon budget variables (fluxes and stocks), ecosystem traits (e.g. leaf area index, age), as well as ancillary site information such as management regime, climate, and soil characteristics. This publicly available database can be used to quantify global, regional or biome‐specific carbon budgets; to re‐examine established relationships; to test emerging hypotheses about ecosystem functioning [e.g. a constant net ecosystem production (NEP) to gross primary production (GPP) ratio]; and as benchmarks for model evaluations. In this paper, we present the first analysis of this database. We discuss the climatic influences on GPP, net primary production (NPP) and NEP and present the CO₂ balances for boreal, temperate, and tropical forest biomes based on micrometeorological, ecophysiological, and biometric flux and inventory estimates. Globally, GPP of forests benefited from higher temperatures and precipitation whereas NPP saturated above either a threshold of 1500 mm precipitation or a mean annual temperature of 10 °C. The global pattern in NEP was insensitive to climate and is hypothesized to be mainly determined by nonclimatic conditions such as successional stage, management, site history, and site disturbance. In all biomes, closing the CO₂ balance required the introduction of substantial biome‐specific closure terms. Nonclosure was taken as an indication that respiratory processes, advection, and non‐CO₂ carbon fluxes are not presently being adequately accounted for.     

甘蔗螟虫卵赤眼蜂繁殖利用的研究

甘蔗是我国最重要的糖料作物,甘蔗害虫以甘蔗螟虫最普遍,分怖亦最廣。廣东珠江三角洲常见的甘蔗螟虫共有四种:条螟或称斑点螟(Diatraea venosata Wk.)、二点螟(Chilo infuscatellus Snellen)、黄螟(Eucosma schistaceana Snellen)和大螟(Sesamiainferens Wk.)。甘蔗螟虫为害的结果,形成枯心苗和蛀(?),影响甘蔗生长发育,减低蔗糖成份,易受风折,而且造成甘蔗赤腐病菌入侵条件。 甘蔗螟虫的为害虽重,但目前还没有一套完整的防治方法,也还没有一种很有效的方法。本试验目的,是利用赤眼蜂来防治甘蔗螟虫。试验内容是赤眼蜂的寄主的选择和繁殖、赤眼蜂的繁殖及保存、赤眼蜂田间放播初步试验和甘蔗螟虫田间发生情况的调查。现将各项试验结果简要地分述如下: 赤眼蜂能否利用成功,要看培育出来的赤眼蜂是否具有高度的生活力。赤眼蜂的生活力可用下列四个标准去量度:(1)蜂体大小,(2)繁殖能力,(3)成虫寿命,(4)对田间环境的適应性。此外,繁殖出来的赤眼蜂雌性此率不应此自然界的减低。 赤眼蜂的生活力,首先和寄主有很大关系。如果寄主卵的内含物的质和量都適合 於赤眼蜂幼虫营养之需,羽化出来的成虫体积大,繁殖力强,寿命也有延长的趣势。关於赤眼蜂的寄主,我们管用过17种鳞翅目昆虫的卵供其寄生,结果以松毛虫(Dendro