光敏核不育水稻中光敏色素的分析

本文报道了在育性转换敏感期光周期处理对光敏核不育水稻（农垦58S）及农垦58最新全展叶中光敏色素Ⅰ(PhyA)水平的影响PartI）．在10个光周期处理的最后一个暗期结束前,收获每株水稻的最上部二叶。PhyA用酶联免疫吸附测定法(ELISA)测定。 结果表明：0.5%(v／v)聚乙烯亚胺(PEI)可除去水稻叶片粗提液中干扰ELISA的物质;所用的ELISA专一性地检测水稻PhyA。和长日照(LD)处理相比，短日照(SU)处理导致农垦58S中PhyA的相对含量增加38.5%;而农垦58只增加18.5%。显然，在较长的暗期条件下（SD），农垦58S中PhyA的合成比农垦58快。SD处理下大量增加的PhyA可能和农垦58S的育性恢复有关。 上述结果也说明：在同一品种甚至不同品种的植株间，PhyA水平均易受光周期影响而剧烈变化。 为了进一步验证农垦58S中PhyA较快积累的推论，比较了农垦58s和农垦58幼苗（三叶期）在一延长暗期(24h)中PhyA的积累时程。和育性转换敏感期的植株相似，农垦58S幼苗中PhyA积累速度快于农垦58。在暗期开始6h后，这种差异更明显。这一结果证实了过去的假设：甲基化水平低的农垦58PhyA基因可能比农垦58PhyA基因更活跃地表达。 PhyA和PhyB同时存在于水稻叶片中。为了探讨PhyB是否参与农垦58S雄性不育的调节，在育性转换敏感期每日光期结束、暗期开始开始前进行短暂的FR照射实验(即end-of- dayFR irradiations)。EOD FR反应应由PhyB介导。和SD下的对照相比，经过10次EODFR处理(EOD FR+SD)的农垦58S植株抽穗和开花期都相应地推迟2天，而花粉败育率和种子结实率都没有变化。 EODFR处理抑制了农垦58的开花，但花粉育性几乎不受影响。 综上所述，可能是PhyA而不是PhyB参与调节农垦58S的雄性不育。 另外，本文采用免疫印迹(Immunoblotting or Western blotting)比较了农垦58S和农垦58黄化苗(3天龄)中PhyA的相对含量(PartⅡ)。 结果表明，RPA可以专一性地检测两品种中120KD多肽。该肽在照射R或FR后对内源蛋白酶水解的敏感性不同，照射FR后，该肽易降解产生116KD的片段;照射R后，相对较稳定。因此，上述120KD多肽是水稻PhyA。未观察到农垦58S和农垦58的PhyA在免疫原性、分子量及内源蛋白酶解水解带型有差异。定量分析表明农垦58s黄化苗中PhyA的相对含量比农垦58多40%。这一结果和上述光周期处理的结果是相辅相成的。由于干种子、以及吸涨36h以前的水稻胚中均检测不PhyA的存在，因此两品种间PhyA含量的差异是PhyA蛋白重新合成的结果。 活体低温(80K)荧光光谱分析表明：农垦58黄化苗（3天龄）具有典型光敏色素(主要为PhyA）的荧光发射，其最大波长为683.8nm，而农垦58S以及由其转育来的培矮64s都缺少明显的光敏色素峰。显然，农垦58S和农垦58的PhyA荧光光谱特性有所不同。这一差异是否和雄性不育有关仍待深入研究。 本文第三部分比较了农垦58S和农垦58黄化苗（6天龄）最初转到白光下(4h)合成叶绿素的情况。无论是短暂红光(R)处理或对照，农垦58幼苗合成叶绿素的量（在白光下4h）都多于农垦58S。由于R促进叶绿素合成的效果可被随后的远红光照射(FR)逆转，因此水稻幼苗中叶绿素合成是在光敏色素的控制下。FR逆转性在农垦58S中似乎更完全。连续FR（12h最有效）促进叶绿素合成的效果在农垦58S中更明显，但叶绿素合成的量（在白光下4h）仍是农垦58多。然而，对于自然光周期下生长的幼苗（2-4叶期），农垦58S的叶绿素含量明显高于农垦58。文中讨论了这种差异的可能原因。

Bm-TFF2, a trefoil factor protein with platelet activation activity from frog Bombina maxima skin secretions

In mammals, trefoil factor family (TFF) proteins are involved in mucosal maintenance and repair, and they are also implicated in tumor suppression and cancer progression. A novel two domain TFF protein from frog Bombina maxima skin secretions (Bm-TFF2) has been purified and cloned. It activated human platelets in a dose-dependent manner and activation of integrin a(11b)beta(3) was involved. Aspirin and apyrase did not largely reduce platelet response to Bm-TFF2 (a 30% inhibition), indicating that the aggregation is not substantially dependent on ADP and thromboxane A2 autocrine feedback. Elimination of external Ca2+ with EGTA did not influence the platelet aggregation induced by Bm-TFF2, meanwhile a strong calcium signal (cytoplasmic Ca2+ release) was detected, suggesting that activation of phospholipase C (PLC) is involved. Subsequent immunoblotting revealed that, unlike in platelets activated by stejnulxin (a glycoprotein VI agonist), PLC gamma 2 was not phosphorylated in platelets activated by Bm-TFF2. FITC-labeled Bm-TFF2 bound to platelet membranes. Bm-TFF2 is the first TFF protein reported to possess human platelet activation activity. (c) 2005 Elsevier Inc. All rights reserved.

The complete amino acid sequence of growth hormone and partial amino acid sequence of prolactin and somatolactin from sea perch (Lateolabrax japonicus)

Growth hormone (GH), prolactin (PRL) and somatolactin (SL) were purified simultaneously under alkaline condition (pH 9.0) from pituitary glands of sea perch (Lateolabrax japonicas) by a two-step procedure involving gel filtration on Sephadex G-100 and reverse-phase high-performance liquid chromatography (rpHPLC). At each step of purification, fractions were monitored by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and by immunoblotting with chum salmon GH. PRL and SL antisera. The yields of sea perch GH, PRL and SL were 4.2, 1.0 and 0.28 mg/g wet tissue, respectively. The molecular weights of 19,200 and 20,370 Da were estimated by SDS-PAGE for sea perch GH and PRL, respectively. Two forms of sea perch SL were found: one (28,400 Da) is probably glycosylated, while the other one (23,200 Da) is believed to be deglycosylated. GH bioactivity was examined by an in vivo assay. Intraperitoneal injection of sea perch GH at a dose of 0.01 and 0.1 mug/g body weight at 7-day intervals resulted in a significant increase in body weight and length of juvenile rainbow trout. The complete sea-perch GH amino acid sequence of 187 residues was determined by sequencing fragments cleaved by chemicals and enzymes. Alignment of sea-perch GH with those of other fish GHs revealed that sea-perch GH is most similar to advanced marine fish, such as tuna, gilthead sea bream, yellowfin porgy, red sea bream, bonito and yellow tail with 98.4, 96.2%, 95.7%, 95.2%, 94.1% and 91% sequence identity, respectively. Sea-perch GH has low identity to Atlantic cod (76.5%), hardtail (73.3%), flounder (68.4%), chum salmon (66.3%), carp (54%) and blue shark (38%). Partial amino-acid sequences of 127 of sea-perch PRL and the N-terminal of 16 amino-acid sequence of sea-perch SL have been determined. The data show that sea-perch PRL has a slightly higher sequence identity with tilapia PRL( 73.2%) than with chum salmon PRL(70%) in this 127 amino-acid sequence. (C) 2001 Elsevier Science B.V. All rights reserved.