西藏色季拉山暗针叶林苔藓多样性及林窗干扰的影响

为了解西藏色季拉山暗针叶林苔藓多样性及林窗干扰的影响,在过去工作积累的基础上研究了色季拉山西坡5块样地内不同林内环境(林窗、林缘和林下)地面、腐木和树附生苔藓生物量特征。结果表明, 地面生单位面积苔藓植物生物量储量最高,平均910.10 g/m²,其次为腐木生(221.90 g/m²),树附生的最低(53.59 g/m²)。林窗地面生苔藓单位面积生物量最高,均值为360.47 g/m²,其次为林下(305.51 g/m²),最小为林缘(244.11 g/m²);林窗、林缘和林下间的地面生苔藓单位面积生物量差异显著(P＜0.05)。沿海拔梯度,林窗苔藓单位面积生物量表现出先增加后减少的趋势。因此,在西藏色季拉山暗针叶林内,林窗对地面生苔藓单位面积生物量有显著影响。     

番茄感染TMV诱导的β-1,3-葡聚糖酶的纯化和性质

番茄系统感染TMV诱导对胞外β—1,3—葡聚糖酶活性升高。番茄叶胞外提取液经冰冻干燥浓缩、-20℃丙酮沉淀、CM-Sephadex C-25离子交换层析和PBE 94聚焦层析纯化,获得PAGE和SDS-PAGE均一的β—1,3—葡聚糖酶。测得该酶的分子量为22kD;以昆布多糖为底物,该酶的最适pH5.4,最适温度30～40℃;K_m和V_(max)值分别为5.64mg/ml和 0.328nmol/s。在感染TMV的番茄叶中,β—1,3—葡聚糖酶活力大部分位于胞外,它是番茄叶胞外提取液中主要的病原相关蛋白。     

乙烯在绿豆下胚轴不定根形成中的作用

选择易产生不定根的绿豆下胚轴做试验材料,研究乙烯在不定根形成中的作用。试验指出,乙烯利和乙烯气体在低浓度下(1—5mgL~(-1))促进或不抑制不定根的形成,随着浓度增加,抑制作用加强。IBA促进不定根形成的作用十分显著。IBA和乙烯相结合的试验说明,两者的作用似乎是独立的。可以设想,存在一个适于生根的低内源乙烯的界限,超过这个界限,抑制不定根形成。     

Comparative analysis of 343 plastid genomes of Solanum section Petota: Insights into potato diversity,phylogeny, and species discrimination

Common potato (Solanum tuberosum L.) and its wild relatives belong to Solanum section Petota. This section's phylogeny and species delimitation are complicated due to various ploidy levels, high heterozygosity, and frequent interspecific hybridization. Compared to the nuclear genome, the plastid genome is more conserved, has a haploid nature, and has a lower nucleotide substitution rate, providing informative alternative insights into the phylogenetic study of section Petota. Here, we analyzed 343 potato plastid genomes from 53 wild and four cultivated species. The diversity of sequences and genomes was comprehensively analyzed. A total of 24 species were placed in a phylogenetic tree based on genomic data for the first time. Overall, our results not only confirmed most existing clades and species boundaries inferred by nuclear evidence but also provided some distinctive species clade belonging and the maternally inherited evidence supporting the hybrid origin of some species. Furthermore, the divergence times between the major potato clades were estimated. In addition, the species discriminatory power of universal barcodes, nuclear ribosomal DNA, and whole and partial plastid genomes and their combinations were thoroughly evaluated; the plastid genome performed best but had limited discriminatory power for all survey species (40%). Overall, our study provided not only new insights into phylogeny and DNA barcoding of potato but also provided valuable genetic data resources for further systematical research of Petota.     

黑龙江省低额溞属的种类及分布（鳃足纲：双甲目）

本文对黑龙江省低额属Ｓｉｍｏｃｅｐｈａｌｕｓ的种类及分布进行了初步的调查。鉴定出低额９种,即锯顶低额Ｓｉｍｏｃｅｐｈａｌｕｓｓｅｒｒｕｌａｔｕｓ,老年低额Ｓ．ｖｅｔｕｌｕｓ,拟老年低额Ｓ．ｖｅｔｕｌｏｉｄｅｓ,棘爪低额Ｓ．ｅｘｓｆｉｎｏｓｕｓ,西伯利亚低额Ｓ．ｓｉｂｉｒｉｃｕｓ,角壳低额Ｓ．ｌｕｓａｔｉｃｕｓ,微齿低额Ｓ．ｈｉｍａｌａｙｅｎｓｉｓｍｉｃｒｏｄｕｓ,黑龙江低额Ｓ．ｈｅｉｌｏｎｇｊｔａｎｇｅｎｓｉｓ和北安低额Ｓ．ｂｅｉａｎｅｎｓｉｓ。对各种低额的形态特征及分布特点作了概括并编制了种的检索表。对所述各种的模式形态及已获种中雄体的精子形态提供活体照片。对部分低额生活环境中的几种主要因子进行了测试,其结果表明,本属各种多生活在水质清洁溶解氧较高且偏碱的水环境中,其水质多在寡污到β中污之间。     

布氏四鼠在低温条件下的实验观察

实验在－２０℃的低温下进行。结果表明。（１）单笼饲养鼠平均存活期为１４５．９±３０．８ｈ。其中幼鼠耐低温力最差。然后依次为老体组、亚成体组、成体组。除幼体外,雌鼠的抗寒能力稍高于雄体。（２）饲喂冷蒿组比饲喂其它６种牧草在低温下布氏田鼠的存活期显著延长．（３）聚集可明显增强对低温的耐受程度。（４）窝草可使巢内温度保持在５～８℃,窝巢内层的温度可达１５～２２℃。     

玉米种子萌发成苗不同阶段需水阈值的研究

用渗透势不同的聚乙二醇（ＰＥＧ）６０００模拟外界环境水分条件,对玉米不同品种的种子在萌动、萌发及成苗三个阶段需水的量化研究表明,种苗的抗旱性随吸水进程的推进而减弱;种子在萌动、萌发及胚芽伸长至一定长度的时间（ｔ）与外界环境水势（ｗ）之间存在着１／ｔ＝ａ＋ｂｗ的关系,据此推算出不同品种在不同成苗阶段的需水阈值,发现不同品种在同一成苗过程中对环境水分条件的反应不同,它们的抗旱性也不同。     

利用IL－3／GM－CSF融合蛋白（PIXY－321）扩增脐血造血细胞方法的初步建立

利用单克隆抗体免疫磁珠吸附方法分离脐血ＣＤ３４＋细胞,并观察了ＩＬ３／ＧＭＣＳＦ融合蛋白（ＰＩＸＹ３２１）对脐血ＣＤ３４＋细胞的刺激作用。ＰＩＸＹ３２１对脐血ＣＤ３４＋细胞扩增作用大于ＩＬ３和ＧＭＣＳＦ单独及联合应用。在液体培养条件下,每毫升２０ｎｇＰＩＸＹ３２１可有效地扩增脐血造血祖细胞,适宜扩增时间为５－８天,扩增后造血祖细胞的数量可达扩增前的８－１０倍,从而初步建立了一种简单可行的脐血造血细胞扩增方法。     

Reversion of malignancy in human gastric cancer MKN—45 cells through the transfection of transforming growth factor—β type Ⅱ receptor gene

Human gastric cancer MKN-45 cells which are resistant to TGF-β growth inhibition and possess TGF-β type I and type Ⅲ receptors,but not type Ⅱ receptors,have been used as a model system to reconstitute these cancer cells with TGF-β RII cDNA.The results of these experiments indicated that the reexpression of TGF-β RII gene in MKN-45 cells can restore their sensitivity to TGF-β growth inhibition,decrease their growth rate,reduce their cloning efficiency in soft agar and tumorigenicity in nude mice in stable transfectants,in comparison with their control MKN-45 cells.Among different RII transfectants,their difference in the changes of these parameters,as a result of the regain of autocrine negative growth control by TGF-β,is roughly proportional to their level of expression of transfected RII mRNA.From these data,it is concluded that the inactivation of TGF-β RII gene is related to the escape of growth control by TGF-β in MKN-45 cells.The importance of the study of the interplay of TGF-β and its receptor system in the negative growth control of gastric cancer,and possibly also of other cancers,is discussed.