表达HSV－2 gD基因的重组痘苗病毒保护小鼠对抗致死量HSV病霉攻击

利用ＰＣＲ方法对单纯疱疹病毒Ⅱ型糖蛋白Ｄ（ＨＳＶ－２ｇＤ）基因进行了修饰,在其５＇端删去约５００ｂｐ的非编码区,仅保留ＡＴＧ上游７个ｂｐ。将修饰后的ＨＳＶ－２ｇＤ基因插入到带有痘苗病毒天坛株ＴＫ基因区段的痘苗表达质粒ｐＪＳＡ１１７５,置于痘苗病毒Ｐ７．５ｋ早／晚期启动子控制下。将此重组质粒用脂质体Ｌｉｐｏｆｅｃｔｉｎ方法转染已受野型ＴＫ￣＋痘苗病毒天坛株感染的ＴＫ￣－１４３细胞,通过同源重组机制和标志基因ＬａｃＺ产物的蓝斑显色作用,以及ＢｕｄＲ试剂对ＴＫ表型的选择压力,筛选出整合有ＨＳＶ－２ｇＤ基因的重组痘苗病毒。Ｓｏｕｔｈｅｍ杂交表明,ＨＳＶ－２ｇＤ基因已正确地插入痘苗病毒ＴＫ基因区内;间接免疫荧光检测显示,ＨＳＶ－２ｇＤ蛋白已得到有效表达,且主要分布于细胞膜。重组病毒免疫家兔可产生明显的抗ＨＳＶ－２ｇＤ中和抗体。用重组病毒免疫小鼠,３周后可使９４％（１７／１８）的小鼠对抗ＨＳＶ－２的致死量攻击,表明重组病毒具有明显的免疫保护作用。     

野生紫斑牡丹和四川牡丹种子萌发特性及与其致濒的关系

野生牡丹种子一般较小,而且不同产地之间形状、大小差异较大。其萌发特性与栽培牡丹相比也有较大差异：萌发期长达半年以上,且萌发温度在１０～１５℃为宜,超过２０℃则明显不利于生根及上胚轴生长。四个不同分布地的四川牡丹种子萌发率较一致,均在６０～７７％之间。三个不同产地的紫斑牡丹种子萌发率则相差甚远,分布于甘肃文县的萌发率达７６％,而分布于陕西略阳和湖北神农架的萌发率则分别只有１２％和４．４％,出苗率则更低。本文认为紫斑牡丹的种子特性是其在自然界处于濒危状态的重要原因之一。     

Studies on homoveratric acid transformation by the ligninolytic fungus Pleurotus eryngii

Homoveratric acid (HVA) degradation was observed in cultures of Pleurotus eryngii lacking lignin peroxidase (LiP) activity. Extracellular enzymes seemed responsible for this transformation, and the lack of activity after ultrafiltration of the culture liquid suggests that the presence of some low-molecular-size compounds is required. This hypothesis is supported by rapid HVA transformation after addition of the synthetic laccase substrate 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) to the ultrafiltered liquid. HVA transformation by the extracellular enzymes from P. eryngii takes place via C-C breakdown and formation of veratryl alcohol, which is further transformed into veratraldehyde. The same major compounds were found during HVA transformation by LiP from Phanerochaete chrysosporium, but this reaction was not stimulated by ABTS. Although the involvement of other enzymes cannot be ruled out, purified laccase from Pleurotus eryngii caused the same HVA transformation pattern in presence of ABTS. Moreover, veratryl alcohol oxidation by P. eryngii laccase was demonstrated in the presence of ABTS. These results suggest that enzymatic systems lacking LiP could be responsible for natural degradation of lignin.     

Pollen-ovule ratio,pollen size,and breeding system in Astragalus (Fabaceae) subgenus Epiglottis: a pollen and seed allocation approach

The correlation between pollen/ovule (P/O) ratio and breeding system has generally been accounted for either on the basis that P/O reflects pollination efficiency, or in terms of the sex allocation theory. The following were assessed for taxa belonging to genus Astragalus subgenus Epiglottis: 1) Degree of correlation between P/O and the breeding system, measured by means of autofertility; 2) The absence or existence of correlation between P/O and pollen grain size; and 3) The ability of various theories to account for the results obtained. Results showed a minimal correlation between P/O and autofertility, and between P/O and pollen grain size in the taxa studied. Analysis of these results in terms of the sex allocation theory enabled this correlation to be explained as a function of the variation existing between taxa with respect to the resources invested in each pollen grain and in each ovule. The predictive capacity of this theory, which has moreover proven valuable in explaining the structural peculiarities of the androecium in these taxa, was also highlighted. The type of self-pollination applicable was also discussed, as was the phenotypic model of selection of self-fertilization considered most plausible for these taxa.     

Comparison of superovulatory response of mature outbred mice treated with FSH or PMSG and developmental potential of embryos produced

A superovulatory treatment for mice based on FSH administration was compared with a standard one based on PMSG. Our aim was to determine if a mean number of embryos recovered per donor could be increased and if in vitro or in vivo viability was affected by the hormonal treatment used. Thus, female Swiss mice were subjected to 2 superovulatory treatments, and the 1-cell and 2-cell stage embryos were cultured in 2 different media to the blastocyst stage or were transferred to pseudopregnant recipients. The data show that despite a lower mating percentage (52% with FSH vs 66% with PMSG), the FSH-treated mice provided twice the number of total embryos (53.4 vs 24.5) with a similar percentage of morphologically normal embryos (74% for FSH vs 69% for PMSG). We also found that in vitro culture results can be influenced by the source of gonadotropins depending on the culture medium used. A culture medium such as CZB which prevents the 2-cell block, provided the same developmental rates regardless of hormonal treatment used. However, with M-16 medium, which does not prevent this blockage, only 39% of the 2-cell FSH-derived embryos and 49% of the PMSG-derived 2-cell embryos developed into blastocysts (P<0.05). FSH-derived embryos resulted in a higher percentage of pregnant recipients (73 vs 56%) than PMSG-derived embryos, but the number of alive fetuses and the number of implantations per pregnant recipient was affected only by the kind of culture system used before transfer. The results show that FSH can provide very good superovulatory response in mice, thus reducing the number of donors needed for a given experiment and providing embryos of at least the same quality as those derived from the standard PMSG treatment.     

Association of a 76 kDa polypeptide with soluble starch synthase I activity in maize (cv B73) endosperm

Soluble starch synthase (SSS) I was purified 361-fold from hand-dissected endosperm tissue of inbred maize (Zea mays, cv. B73) to specific activities ranging between 5 and 9 µmol min⁻¹ mg⁻¹. A key to this purification protocol was the introduction of a size-exclusion chromatography step, a size-based fractionation which provided abundant levels of desalted SSS forms I and II. The native molecular masses calculated for SSS forms I and II were 75.5 kDa and 180 kDa, respectively. SSSI was then further purified by hydrophobic interaction chromatography on Phenyl-Superose and by FPLC on Mono Q. Analysis of column peaks by SDS—PAGE and scanning densitometry revealed that a 76 kDa polypeptide is strongly correlated with SSSI activity. Antibodies were then generated against a 76 kDa polypeptide extracted from starch granules. These antibodies, which were monospecific for the soluble 76 kDa polypeptide, neutralized greater than 90% of SSSI activity, and precipitated the 76 kDa protein. These results establish the 76 kDa protein as an SSSI in the B73 line of inbred maize. An immunologically similar 76 kDa protein also appears to be tightly associated with the starch granule.     

祁连山地区植被特征及其分布规律

分析和讨论了祁连山地区主要植被类型及其分布特征。祁连山地区随着青藏高原的强烈隆升表现为整体抬升,植被具有明显的生态地理边缘效应特征和高原地带性规律。该区植被虽然受到四周的较大影响,但各类高寒植被占有绝对优势,表现出与青藏高原植被整体明显的相似性和广泛的一致性。另一方面,本区植被也有其特殊性及与高原面存在一些差异。因此,建议把祁连山地区做为青藏高原植被区的次一级独立单元     

质体醌重组的D1／D2／Cytb559复合物的荧光衰减动力学和光破坏作用

光系统Ⅱ反应中心Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 在分离纯化过程中失去了电子受体ＱＡ 和ＱＢ,人工合成的质体醌可以与Ｄ１／Ｄ２／Ｃｙｔｂ５５９ 复合物发生重组。癸基质体醌（ＤＰＱ）与Ｄ１／Ｄ２／Ｃｙｔｂ５９９ 复合物的重组导致该复合物的荧光强度下降及发射光谱蓝移,同时两个与光化学活性相关的长寿命（２４ ｎｓ和７３ ｎｓ）荧光衰减组分占整个荧光的百分数下降,这些结果表明ＤＰＱ作为Ｐｈｅｏ－ 的电子受体,限制了Ｐ６８０＋ ·Ｐｈｅｏ－ 的电荷重组。ＤＰＱ 的加入对Ｄ１／Ｄ２／Ｃｙｔｂ５５９复合物中Ｃｈｌａ 分子的光破坏敏感性影响不大,但β－胡萝卜素在加入ＤＰＱ 之后可以被光照破坏,这个过程可能与β－胡萝卜素的生理功能相关。     

In vitro survival of murine morulae after quick freezing in the presence of chemically defined macromolecules and different cryoprotectants

We studied the ability of frozen-thawed mouse morulae to develop in vitro when the cryoprotectant proteins were substituted with one of the following nonorganic macromolecules: polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), and ficoll. We also determined how these agents interacted with 3 different cryoprotectants: glycerol (GLY), propylene glycol (PG), and ethylene glycol (EG). The influence of both of the above factors was measured on the basis of post-thaw morphological appearance, the percentage of development to the expanded blastocyst stage and the total cell count. Morulae (n=950) were collected from superovulated mice. Those classified as good or excellent were distributed among the 12 different freezing solutions, obtained by combining the 3 cryoprotectants with the 4 macromolecules (the 3 mentioned above, plus a control of 5% fetal calf serum) in phosphate buffered saline (PBS). Embryos frozen in PVA, PVP and ficoll tended to be a little difficult to recover from the straws. Development to the expanded blastocyst stage was significantly lower (P<0.05) in propylene glycol (43.6%) than in ethylene glycol (79.5%) or in glycerol (76.1%). Polyvinyl alcohol provided a higher survival rate when combined with glycerol (90.3) or ethylene glycol (95.0), but when it was combined with propylene glycol, only 56.5% of embryos survived after thawing. A positive interaction was observed between glycerol and PVA and between ethylene glycol and PVA or ficoll. The results indicate that fetal serum could be successfully substituted for any of the 3 chemically defined macromolecules. However, our findings also suggest that the use of PG as a cryoprotectant should be avoided when mouse morulae are frozen using the quick freezing method.     

促髓细胞分化的锌指基因单向PCR扩增直接测序的研究

锌指基因是一种造血调节基因,编码锌指结构蛋白,主要在髓细胞中表达,促进髓细胞分化,在急性早幼粒白血病维甲酸治疗中,促使病情缓解。本文报道了我们从基因分子上研究锌指基因作用中,探索并建立了单向聚合酶链反应（ＰＣＲ）扩增特定单链ＤＮＡ,直接测序的新方法。它能产生质和量均佳的单链ＤＮＡ,无需纯化即可直接用于测序,使复杂的测序研究简便易行,可在２,３天内完成。这种单向ＰＣＲ扩增特定单链ＤＮＡ直接测序的方法,经对锌指基因的ｃＤＮＡ测序,得到验证。此法不仅适用于疾病研究中的ＤＮＡ测序,还可制各单链ＤＮＡ探针,更利于基因结构组成的研究。