多点接种方法计数土壤细胞生理类群的研究

多点接点计数方法是根据细菌分解固体培养基上不同的有机化合物的能力确定为不同的生理类群,由有机化合物的降解点数和根据MPN方法进行计数,对不同的耕作方法进行了测定表明,秸秆覆盖免肾够明显提高土壤中分解淀粉,木聚糖,纤维素,果胶,几丁质,卵磷质,脂类和蛋白质类群的细菌数量。     

1983～1992年中国陆地NDVI变化的气候因子驱动分析

利用1983－1992年NOAA／AVHRR逐月的归一化植被指数（NDVI）资料和中国国家气象局全国160个基本标准气象站的月均温和降雨数据,探讨气温,降水对中国植NDVI动态变化驱动作用。首先计算了NDVI与气温,降水偏相关和复相关系数,研究了中国植被NDVI变化的气候因子驱动的区域分异规律,并据此,对中国植被NDVI变化的气候因子驱动进行了分区,共分出4个一级区,6个二级区和14个三级区,进一步表明了中国植被NDVI变化气候因子驱动的区域差异。     

Physical mapping and microsynteny of Brassica rapa ssp. pekinensis genome corresponding to a 222 kbp gene-rich region of Arabidopsis chromosome 4 and partially duplicated on chromosome 5

We constructed a bacterial artificial chromosome (BAC) library, designated as KBrH, from high molecular weight genomic DNA of Brassica rapa ssp. pekinensis (Chinese cabbage). This library, which was constructed using HindIII-cleaved genomic DNA, consists of 56,592 clones with average insert size of 115 kbp. Using a partially duplicated DNA sequence of Arabidopsis, represented by 19 and 9 predicted genes on chromosome 4 and 5, respectively, and BAC clones from the KBrH library, we studied conservation and microsynteny corresponding to the Arabidopsis regions in B. rapa ssp. pekinensis. The BAC contigs assembled according to the Arabidopsis homoeologues revealed triplication and rearrangements in the Chinese cabbage. In general, collinearity of genes in the paralogous segments was maintained, but gene contents were highly variable with interstitial losses. We also used representative BAC clones, from the assembled contigs, as probes and hybridized them on mitotic (metaphase) and/or meiotic (leptotene/pachytene/metaphase I) chromosomes of Chinese cabbage using bicolor fluorescence in situ hybridization. The hybridization pattern physically identified the paralogous segments of the Arabidopsis homoeologues on B. rapa ssp. pekinensis chromosomes. The homoeologous segments corresponding to chromosome 4 of Arabidopsis were located on chromosomes 2, 8 and 7, whereas those of chromosome 5 were present on chromosomes 6, 1 and 4 of B. rapa ssp. pekinensis.     

两种除草剂对棉田节肢动物群落多样性指数的影响

系统地研究了棉田地面和棉株节肢动物群落及各亚群落施用克无踪(A)、高盖(B)与对照(CK)之间在群落生物多样性、丰富度和均匀度的差异.结果表明,对地面肉食动物群落生物多样性(H′)的A-CK的t值为3.099,B-CK的t值为2.449,t＞t_0.05=2.228,差异显著;地面植食动物亚群落的(H′)A-CK的t值为2.377,A-B为2.260,t＞t_0.05=2.228,差异均显著.棉株节肢动物群落及亚群落A-CK、B-CK和A-B之间差异不显著.地面节肢动物亚群落丰富度A-CK的t值为4.759,地面植食类节肢动物亚群落为4.359,地面肉食节肢动物亚群落为2.963,均t＞t0.0=2.228,表明A与CK之间差异显著;在均匀度上,A和B及A-CK、B与CK之间两类群落及亚群落上差异均不显著.A和B对棉株节肢动物群落影响很小.施用A和B及CK的生物多样性的变化总趋势一致.     

Growth of Pichia guilliermondii A9, an osmotolerant yeast, in waste brine generated from kimchi production

The possibility of culturing an osmotolerant yeast using waste brine from a kimchi factory as a substrate for the production of single cell protein was investigated. Pichia guilliermondii A9 was selected from 70 isolates of yeast demonstrating substantial growth in the waste brine. The growth of P. guilliermondii A9 in waste brine was not inhibited by NaCl concentrations of up to 10% (w/v). However, it was reduced drastically at concentrations greater than 12% (w/v). Approximately 90% of BOD was removed from the waste brine by culturing of P. guilliermondii A9 for 24 h. The maximum cell yield was 0.69 g of dry cells per liter, containing 40% of protein. When the waste brine was enriched with cabbage juice from waste cabbage, the final cell mass increased proportionally with the amount of added organic material. Salt stressed cells of P. guilliermondii A9 grown in waste brine are shown in scanning electron micrographs. In conclusion, the large amounts of waste brine generated from kimchi production could be used directly for the culture of the osmotolerant yeast P. guilliermondii A9.     

贵州地方山羊品种的RAPD分析

用180条引物对黔东南小香羊、贵州白山羊、贵州黑山羊和黔北麻羊4个贵州地方山羊品种(种群),以及南江黄羊和波尔山羊进行RAPD分析,其中27条引物扩增出多态性图谱。这27条引物共扩增出281条带,多态带为115条,平均多态频率为40．92％(范围20％～80％);每条引物平均扩增条带为10．41条(范围4～16条);扩增带分子量在210～2800bp。贵州白山羊与贵州黑山羊之间的遗传距离指数(0．0605)最小,而波尔山羊与其他品种之间的遗传距离指数(0．1059～0．1488)最大。NJ法聚类结果显示,贵州白山羊与贵州黑山羊间的亲缘关系最近,其次为黔北麻羊,而黔东南小香羊与其他3个贵州地方品种的亲缘关系较南江黄羊还远。分析表明,黔东南小香羊在遗传上为一独立的品种;而贵州地方山羊品种间具有较近的亲缘关系,遗传变异较小,具有较高的遗传稳定性。     

家蚕抗菌肽在毕赤酵母中的表达

目的：用毕赤酵母真核系统表达有抑菌活性的家蚕抗菌肽(cecropin-XJ)。将pGEX-4T-1-cecropin-XJ上的抗菌肽基因cecropin—XJ克隆至穿梭质粒pSuperY上,用Bln Ⅰ酶切使之线性化后,采用电击法转化酵母SMD1168,转化子用小瓶发酵,经SDS—PAGE检测,表达产物可以在α信号因子的引导下,分泌到培养基中,且表达产物具有明显抑菌活性。     

Cellular Internalization of Exosomes Occurs Through Phagocytosis

Exosomes play important roles in many physiological and pathological processes. However, the exosome–cell interaction mode and the intracellular trafficking pathway of exosomes in their recipient cells remain unclear. Here, we report that exosomes derived from K562 or MT4 cells are internalized more efficiently by phagocytes than by non‐phagocytic cells. Most exosomes were observed attached to the plasma membrane of non‐phagocytic cells, while in phagocytic cells these exosomes were found to enter via phagocytosis. Specifically, they moved to phagosomes together with phagocytic polystyrene carboxylate‐modified latex beads (biospheres) and were further sorted into phagolysosomes. Moreover, exosome internalization was dependent on the actin cytoskeleton and phosphatidylinositol 3‐kinase, and could be inhibited by the knockdown of dynamin2 or overexpression of a dominant‐negative form of dynamin2. Further, antibody pretreatment assays demonstrated that tim4 but not tim1 was involved in exosomes uptake. We also found that exosomes did not enter the internalization pathway involving caveolae, macropinocytosis and clathrin‐coated vesicles. Our observation that the cellular uptake of exosomes occurs through phagocytosis has important implications for exosome–cell interactions and the exosome intracellular trafficking pathway.     

Design, synthesis, and biological evaluation of novel 4-alkylamino-1-hydroxymethylimidazo[1,2-a]quinoxalines as adenosine A(1) receptor antagonists

A series of 4-alkylamino-1-hydroxymethylimidazo[1,2-a]quinoxalines have been synthesized and evaluated for their adenosine A(1) receptor inhibitory activity in the radioligand binding assays. The compounds were tested for the inhibition percent (IP) and the affinity toward A(1)AR (K(i)) that IP were more than 90% in the nanomolar range. 4-Cyclopentylamino-7,8-dichloro-1-hydroxymethylimidazo[1,2-a]quinoxaline 18 is the most potent compound in this series, having K(i)=7nM, which is remarkably higher than that of IRFI-165 (K(i)=48). 1-Hydroxymethyl groups of the tricyclic heteroarmatic compounds displayed the potent affinities toward A(1)AR.