嗜酸乳杆菌DOMLa菌株thyA基因突变株的筛选

为构建以ｔｈｙＡ基因为选择标记的嗜酸乳杆菌染色体－质粒致死平衡系统。我们建立了嗜酸乳杆菌ｔｈｙＡ基因突变菌株的筛选方法。从含有三甲氧卞氨嘧啶（ＴＭＰ）２０μｇ／ｍｌ和胸腺嘧啶（ｔｈｙｍｉｄｉｎｅ）５０μｇ／ｍｌ的改良ＭＲＳ培养基中筛选了１００株突变株,从中确定一株生物学性状稳定的菌株ＤＯＭＬａＦ８４作为进一步研究的受体侯选菌株。     

离子平衡及其相关信号传导在细胞耐盐中的作用

盐胁迫所造成的毒害作用皆源自细胞中水平衡和离子平衡的破坏,因此可以推断对耐盐起关键作用的基因能恢复细胞内水和离子平衡。鉴于调渗物质的积累对提高细胞耐盐性所起作用有很大差异,其中一些在某些情况下甚至与耐盐无关,本文集中讨论与恢复细胞内离子平衡相关的基因调控及其信号级联系统。盐胁迫时,这些基因产物在相关信号级联系统的协调下,通过有效地降低细胞内Ｎａ＋ 的浓度,增加Ｋ＋ 的吸收,恢复Ｎａ＋ ／Ｋ＋ 比,使细胞获得相当的耐盐性 。     

Isolation of ScFv antibodies of rP27Kip1 from phage display libraries constructed from immunized and non-immunized repertoires

Through mRNA extract, RT and a series of PCR, phage antibody libraries were constructed from rP27^{kip 1}-immunized and non-immunized mice. After only one round of selection with rP27^{kip 1}, clones from each library were chosen randomly and digested byTag I and Hinf I. 11 of 64 clones from the immunized animal had consistent restriction pattern, while none of the 64 clones from the non-immunized animal had, except that one had the same fragments pattern as that of the 11 clones. The 12 fragments were expressed inE. coli BL21(DE3)/pET-28b(+) system. ELISA showed that some of the fragments could bind to rP27^{kip 1} specifically. AU these results implied that specific antibody can be obtained by genetic engineering without hybridoma or many rounds of growth and panning selection.     

RAPD重建的大豆属植物的亲缘关系

利用８种ＲＡＰＤ引物（ＯＰＨ－２、ＯＰＨ－３、ＯＰＨ－５、ＯＰＨ－１２、ＯＰＨ－１５、ＯＰＨ－１６、ＯＰＨ－１８和ＯＰＨ－２０）对大豆属的２１份植物材料,其中包括Ｇｌｙｃｉｎｅ亚属的１０个种和Ｓｏｊａ亚属的３个种,进行了基因组指纹图谱构建。通过对获得的基因组指纹图谱的量化分析,利用Ｕｎｗｅｉｇｈｔｅｄｐａｉｒｇｒｏｕｐｗｉｔｈｍａｔｈｅｍａｔｉｃａｖｅｒａｇｅ（ＵＰＧＭＡ）对大豆属中的各个种进行了亲缘关系重建。重建的亲缘关系表明：Ｇ．ｔｏｍｅｎｔｅｌｌａ种中存在３种不同的进化类型,其分化距离已大于某些种种间的分化距离,它们可能是被形态遮蔽的３个种。Ｓｏｊａ亚属内３个种的分化关系同前人的研究推断相同,其亲缘关系很近,这一结果支持将这３个种归并为一个种的观点。但是重建的亲缘关系未能显示出大豆属两个亚属的划分格局。     

Phylogeny of 12 species of genusGlycine Willd. reconstructed with internal transcribed region in nuclear ribosomal DNA

The ITS-Is of 24 accessions belong to 10 species of subgenusGlycine, and 2 species of subgenusSoja of genusGlycine were amplified, cloned and sequenced. According to the homology of the sequences, the phylogeny of the 24 accessions were reconstructed. The reconstructed dendrogram showed that there were some divergent genomic types found in the previously classified species, such asG. tomentella, G. canescens andG. tabacina, and they might be some cryptic species by morphologic analysis.     

草兔的年龄鉴定和种群结构分析

根据１９９１年２－１０月猎自晋东南的２１２只和１９９０－１９９２年狩猎季节猎自山西和陕西省各地的１５１０只草兔眼晶体重的分布规律并参照繁殖资料,确定２２５毫克为区别１年以下及其以上个体的临界重量。秋－冬季种群中,当年兔占８６．３（７２．２－９３．５）％;随着繁殖季节的推移,当年兔的比例逐渐增加。在４０１１只标本中,雌性占５２．３％;其中１２２６只幼体和１９５只成体中分别有雌性５２．４％和５４．４％。在２－９月所获的９１只当年兔有雌性５０．５％,而成体中雌性则有５８．２％。     

Increased glycine betaine synthesis and salinity tolerance in AhCMO transgenic cotton lines

Glycine betaine is an osmoprotectant that plays an important role and accumulates rapidly in many plants during salinity or drought stress. Choline monooxygenase (CMO) is a major catalyst in the synthesis of glycine betaine. In our previous study, a CMO gene (AhCMO) cloned from Atriplex hortensis was introduced into cotton (Gossypium hirsutum L.) via Agrobacterium mediation to enhance resistance to salinity stress. However, there is little or no knowledge of the salinity tolerance of the transgenic plants, particularly under saline-field conditions. In the present study, two transgenic AhCMO cotton lines of the T₃ generation were used to study the AhCMO gene expression, and to determine their salinity tolerance in both greenhouse and field under salinity stress. Molecular analysis confirmed that the transgenic plants expressed the AhCMO gene. Greenhouse study showed that on average, seedlings of the transgenic lines accumulated 26 and 131% more glycine betaine than those of non-transgenic plants (SM3) under normal and salt-stress (150 mmol l⁻¹ NaCl) conditions, respectively. The osmotic potential, electrolyte leakage and malondialdehyde (MDA) accumulation were significantly lower in leaves of the transgenic lines than in those of SM3 after salt stress. The net photosynthesis rate and Fv/Fm in transgenic cotton leaves were less affected by salinity than in non-transgenic cotton leaves. Therefore, transgenic cotton over-expressing AhCMO was more tolerant to salt stress due to elevated accumulation of glycine betaine, which provided greater protection of the cell membrane and photosynthetic capacity than in non-transgenic cotton. The seed cotton yield of the transgenic plants was lower under normal conditions, but was significantly higher than that of non-transgenic plants under salt-stressed field conditions. The results indicate that over-expression of AhCMO in cotton enhanced salt stress tolerance, which is of great value in cotton production in the saline fields.     

Functional analysis of α1,3/4-fucosyltransferase VI in human hepatocellular carcinoma cells

The α1,3/4-fucosyltransferases (FUT) subfamily are key enzymes in cell surface antigen synthesis during various biological processes. A novel role of FUTs in tumorigenesis has been discovered recently, however, the underlying mechanism remains largely unknown. Here, we characterized FUT6, a member of α1,3/4-FUT subfamily, in human hepatocellular carcinoma (HCC). In HCC tissues, the expression levels of FUT6 and its catalytic product SLe(x) were significantly up-regulated. Overexpression of FUT6 in HCC cells enhanced S-phase cell population, promoted cell growth and colony formation ability. Moreover, subcutaneously injection of FUT6-overexpressing cells in nude mice promoted cell growth in vivo. In addition, elevating FUT6 expression markedly induced intracellular Akt phosphorylation, and suppressed the expression of the cyclin-dependent kinases inhibitor p21. Bath application of the PI3K inhibitor blocked FUT6-induced Akt phosphorylation, p21 suppression and cell proliferation. Our results suggest that FUT6 plays an important role in HCC growth by regulating the PI3K/Akt signaling pathway.     

The Arabidopsis Chaperone J3 Regulates the Plasma Membrane H+-ATPase through Interaction with the PKS5 Kinase

The plasma membrane H⁺-ATPase (PM H⁺-ATPase) plays an important role in the regulation of ion and metabolite transport and is involved in physiological processes that include cell growth, intracellular pH, and stomatal regulation. PM H⁺-ATPase activity is controlled by many factors, including hormones, calcium, light, and environmental stresses like increased soil salinity. We have previously shown that the Arabidopsis thaliana Salt Overly Sensitive2-Like Protein Kinase5 (PKS5) negatively regulates the PM H⁺-ATPase. Here, we report that a chaperone, J3 (DnaJ homolog 3; heat shock protein 40-like), activates PM H⁺-ATPase activity by physically interacting with and repressing PKS5 kinase activity. Plants lacking J3 are hypersensitive to salt at high external pH and exhibit decreased PM H⁺-ATPase activity. J3 functions upstream of PKS5 as double mutants generated using j3-1 and several pks5 mutant alleles with altered kinase activity have levels of PM H⁺-ATPase activity and responses to salt at alkaline pH similar to their corresponding pks5 mutant. Taken together, our results demonstrate that regulation of PM H⁺-ATPase activity by J3 takes place via inactivation of the PKS5 kinase.