Ultracytochemical Localization of Calcium in Micropyle and Embryo Sac of Brassica napus Before and After Pollination

Potassiam antimonate was used to localize Ca2+ in the micropyle and embryo sac of Brassica napus L. before and after pollination. To identify the nature of the pyroantimonate deposits, energy-dispersive X-ray microanalysis (EDXA) was employed and the deposits were proved to contain calcium pyroantimonate. Image processing system was employed to measure the volume density and the diameter of the deposits. Before and after pollination, calcium was more abundant in the exostome and endostome as compared with the other regions of the integuments, and was concentrated at the apoplast system, i.e. the intercellular matrix of the micropyle canal and the cell wall. Before pollination, each of the two sister synergids accumulated more calcium than the other embryo sac cells. Although the mean diameter of the deposits in the synergid was only two-thirds as that in the egg cell and central cell, the volume density of the deposits in the synergid was about 2.5 times and 1.9 times as that in the egg cell and the central cell respectively. The filiform apparatus and the nucleus had the most abundant calcium within a synergid. After pollination both sister synergids degenerated conspicuously and were characterized by much more deposited calcium (about 2.4 times more than before); and the diameter of the deposits decreased dramatically, which was less than one-third as before. The relationship between calcium distribution and synergid degeneration as well as its functions was discussed.     

里氏木霉纤维二糖水解酶Ⅱ在毕赤酵母中的高效表达

本工作采用巴氏毕赤酵母Pichiapastoris表达系统进行了里氏木霉Trichodermareesei纤维二糖水解酶Ⅱ(CellobiohydrolaseII)的表达。用RT-PCR的方法从经稻草粉诱导的里氏木霉培养物中分离出纤维二糖水解酶Ⅱ的基因,将其插入到巴氏毕赤酵母的表达载体pPICZαA中,并使之处于α-因子信号肽序列的下游,得到重组质粒pPICZαA-cbh2。通过电穿孔的方法用线性化的pPICZαA-cbh2转化巴氏毕赤酵母GS115菌株,经过大量筛选后得到可以高效表达纤维二糖水解酶的毕赤酵母菌株P.pastorisCBHⅡ1。在甲醇诱导的条件下培养P.pastorisCBHⅡ1,培养液中的CMC活性可达到3.82U/mL,SDS-PAGE分析结果表明纤维二糖水解酶在P.pastorisCBHⅡ1中的表达量远远高于里氏木霉。对表达产物进行了LC-MS分析,结果表明所表达的蛋白为里氏木霉的纤维二糖水解酶。     

二杈狗牙花的化学成分

从二杈狗牙花（Ｅｒｖａｔａｍｉａｄｉｖａｒｉｃａｔａ（Ｌ．）Ｂｕｒｋ）中共分离出８个已知化合物,分别为３个环菠萝蜜烷型三萜：ｃｙｃｌｏａｒｔ－２３－ｅｎｅ－３β,２５－ｄｉｏｌ（１）,３β－ｈｙｄｒｏｘｙｃｙｃｌｏａｒｔ－２５－ｅｎｅ－２４－ｏｎｅ（２）,ｃｙｃｌｏｅｕｃａｌｅｎｏｌ（３）;２个吲哚生物碱ｅｒｖａｔａｍｉｎｅ（４）和ｔａｂｅｒｎａｅｍｏｎｔａｎｉｎｅ（５）;其他是β－谷甾醇,３β－乙酰－香树脂醇和胡萝卜甙。它们均由波谱方法鉴定。其中环菠萝蜜烷型三萜系首次被发现存在于狗牙花属植物中     

云南松居群遗传学研究的等位酶分析方法

针对１５个云南松Ｐｉｎｕｓｙｕｎｎａｎｅｎｓｉｓ居群,开展了１４种酶系统的水平切片淀粉凝胶电泳实验,在谱带遗传分析的基础上确定了３３个等位酶位点及其等位基因。其中有３２个等位酶位点是多态的（有２个以上的等位基因）,只有一个单态位点Ｄｉａ－４。有３个等位基因的位点有Ｌａｐ－１、Ｌａｐ－２、Ａａ－３、Ｓｋｄ－１、Ｓｋｄ－２、Ａｄｈ－１、Ａｄｈ－３、Ｇｄｈ、Ｐｇｄ－１、Ｐｇｍ－１、Ｐｇｍ－３、Ｐｇｉ－１、Ｐｇｉ－３、Ｍｄｈ－１、Ｍｅ、Ｇ６ｐｄ、Ｄｉａ－１、Ｔｐｉ－１、Ｔｐｉ－２、Ｔｐｉ－３和Ｔｐｉ－４,有４个等位基因的位点有Ｓｋｄ－３、Ａｄｈ－２、Ｐｇｄ－２、Ｍｄｈ－２、Ｍｄｈ－３、Ｍｄｈ－４和Ｄｉａ－２,有５个等位基因的位点有Ａａｔ－１和Ｄｉａ－３。云南松居群的等位基因平均数Ａ＝２１,在松属中居于中上水平。本研究揭示了云南松居群酶位点及其等位基因带谱的变异式样,为松属植物的遗传多样性研究提供了一批酶位点及其等位基因的参考图谱     

分批异养培养小球藻光密度值与干重的关系

在小球藻的分批异养培养过程中,培养液的细胞浊度（ＯＤ）与细胞干重（ＤＷ）的关系受培养条件和培养过程的影响很大,在实验中,干重与光密度值的比值在０．５３～０．２８ｇ／ＯＤ·Ｌ间变化。因此在小球藻分批异养培养过程中,培养液藻生物量检测采用单一的ＤＷ与ＯＤ换算常数用ＯＤ来推算细胞的干重则会产生较大的误差。     

我国的生命科学与生物产业发展的几个问题

１“人类基因组计划（ＨＧＰ）”的昨天与今天“人类基因组计划（ＨＧＰ）”已经６年了,从未有过这样的计划,能够得到全球各国科学家的认同,能够形成全球性的合作,能取得比预期更好的进展,又能如此广泛地冲击社会的方方面面。正确分析、准确把握当前国际上ＨＧＰ的进...     

两种木香型天然香料的化学成分

杉木（Ｃｕｎｍｉｎｇｈａｍｉａｌａｎｃｅｏｌａｔａ（Ｌａｍｂ．）Ｈｏｏｋ）和圆柏（Ｓａｂｉｎａｃｈｉｎｅｎｓｉｓ（Ｌｉｎｎ．）Ａｎｔ．）分别为杉科和柏科的乔木。两种精油样品采自本所栽培植物的心材经蒸馏而得,其得率分别为：杉木油０５９０％,圆柏油０?..     

织锦芋螺ο家族芋螺毒素的序列分析

为了从织锦芋螺（Ｃｏｎｕｓｔｅｘｔｉｌｅ）中尽可能多地分离出ο家族的毒素序列和研究其应用价值,在克隆了织锦芋螺α芋螺毒素的基础上进行了织锦芋螺ο家族芋螺毒素基因的分离工作．从织锦芋螺毒管中提取ｍ ＲＮＡ,通过ＲＡＣＥ（ｒａｐｉｄ ａｍ ｐｌｉｆｉｃａｔｉｏｎ ｏｆｃＤＮＡ ｅｎｄｓ,ｃＤＮＡ 末端的快速扩增）－ＰＣＲ方法扩增获得ο家族芋螺毒素ｃＤＮＡ 片段,并进行克隆和序列分析．从织锦芋螺毒液中获得了６种新的芋螺毒素序列,且毒素序列的成熟肽部分均符合Ｃ－ Ｃ－ ＣＣ－ Ｃ－ Ｃ的保守半胱氨酸框架．这些是新的ο家族芋螺毒素序列,新序列的阐明为进一步研究其生物活性和应用打下了基础．     

尖吻蝮蛇毒NAD糖苷水解酶荧光光谱和荧光猝灭研究

70年代就有报道从蛇毒中提纯NAD糖苷水解酶(NADase,E.C.3.2.2.5)和一些生物性质方面的研究.Huang等[1]从皖南尖吻蝮蛇毒中分离得到的NADase是由两个相同亚基组成,含糖33%,等电点为7.6.刘清亮等[2]研究了NADase的ESR谱,推知Cu2+离子至少与三个氮原子配位.本文主要研究多种?..