Visualization and Characterization of High-Order Chromatin Fibers under Light Microscope during Interphase and Mitotic Stages in Plants

Using genomic in situ hybridization with genomic DNA, high-order chromatin fibers were successfully exhibited under a light microscope through the cell cycle in barley, rice, maize and field bean. From the interphase to prophase and metaphase of mitosis, the fibers were basically similar. Each was estimated to be around 200 nm in diameter, but the strength of signals was not the same along the fiber length. Through the cell cycle a series of dynamic distribution changes occurred in the fibers. In the interphase, they were unraveled. At the early prophase they were arranged with parallel and mirror symmetry. During late-prophase and metaphase, the fibers were bundled and became different visible chromosomes. The parallel coiling and mirror symmetry structures were visible clearly until the metaphase. In anaphase they disappeared. During telophase, in peripheral regions of congregated chromosome group, borderlines of the chromosomes disappeared and the fibers were unraveled. This demonstrated that mitotic chromosomes are assembled and organized by parallel and adjacent coiling of the fibers and the fibers should be the highest order structure for DNA coiling.     

固定化氧化亚铁硫杆菌培养条件对黄铁矾沉淀的影响

以聚乙烯醇-海藻酸钠复合材料为载体,Ca(NO3)2为交联剂对氧化亚铁硫杆菌进行包埋固定化。该固定化细胞的连续培养技术可以用于处理H2S、SO2,为了减少减少固定化细胞培养过程中带来许多不利效应的黄铁矾沉淀 (NH4Fe3(SO4)2(OH)6）,采取了改变初始pH值和目前普遍采用的9K培养基中的(NH4)2SO4浓度,K2HPO4浓度三种方法。结果显示：在三种方法中,降低(NH4)2SO4浓度是比较可行的一种方法,当(NH4)2SO4从3.0 g/L降低到0.5g/L,Fe2+氧化速率几乎没有受到影响,沉淀形成速率却减少了45%。在固定化细胞连续运行时,降低9K培养基中(NH4)2SO4的含量,当稀释率为0.4 h-1,运行时间为96 h,Fe2+氧化速率高达3.75 g/L.H,结果显示反应柱内沉淀明显减少,同时Fe2+氧化速率并没有明显变化。     

红谷霉素对细菌抑制效果研究

红谷霉素是链霉菌702发酵后所产的一种生物活性物质,具有较强抗细菌活性。研究表明,红谷霉素对大肠杆菌的最低抑菌浓度为40mg/L,对枯草芽胞杆菌的最低抑菌浓度为0.08mg/L。红谷霉素在微生物生长迟滞期添加比在其它生长阶段添加抑菌效果更好,红谷霉素对热和紫外比较稳定。通过与其他防腐剂的抑菌效果比较表明,红谷霉素对细菌的抑菌效果优于比较的防腐剂。     

Identification of TAF1, HNF4A,and CALM2 as potential therapeutic target genes for liver fibrosis

The molecular mechanism of liver fibrosis caused by hepatitis C virus (HCV) is not clear. The aim of this study is to understand the molecular mechanism of liver fibrosis induced by HCV and to identify potential therapeutic targets for hepatic fibrosis. We analyzed gene expression patterns between high liver fibrosis and low liver fibrosis samples, and identified genes related to liver fibrosis. We identified TAF1, HNF4A, and CALM2 were related to the development of liver fibrosis. HNF4A is important for hepatic fibrogenesis, and upregulation of HNF4A is an ideal choice for treating liver fibrosis. The gene expression of CALM2 is significantly lower in liver fibrosis samples than nonfibrotic samples. TAF1 may serve as a biomarker for liver fibrosis. The results were further validated by an independent data set GSE84044. In summary, our study described changes in the gene expression during the occurrence and development of liver fibrosis. The TAF1, HNF4A, and CALM2 may serve as novel targets for the treatment of liver fibrosis.     

Triaxial compression test of soil–root composites to evaluate influence of roots on soil shear strength

In order to evaluate influences of roots on soil shear strength, a triaxial compression test was carried out to study the shear strength of plain soil samples and composites comprised of roots of Robinia pseucdoacacia and soil from the Loess Plateau in Northwest China. Roots were distributed in soil in three forms: vertical, horizontal, and vertical–horizontal (cross). All samples were tested under two different soil water contents. Test results showed that roots have more impacts on the soil cohesion than the friction angle. The presence of roots in soil substantially increased the soil shear strength. Among three root distribution forms, the reinforcing effect of vertical–horizontal (cross) root distribution was the most effective. Increase in soil water content directly induced a decline in soil cohesion of all test samples and resulted in a decrease in shear strength for both plain soil samples and soil–root composites. It was concluded that the triaxial compression test can be effectively used to study influences of roots on soil shear strength.     

Nocardia alba sp.nov., a novel actinomycete strain isolated from soil in China

A novel actinomycete strain, designated YIM 30243T, was isolated from a soil sample in Yunnan Province, China. Based on the results of phenotypic and genotypic characteristics, strain YIM 30243T should be assigned to a new species of the genus Nocardia, for which the name Nocardia alba sp. nov. is proposed. The type strain is YIM 30243T (= CCTCC AA001030T = DSM 44684T).     

Luminescent pH sensing and DNA binding properties of a novel ruthenium(II) complex

A new Ru(II) complex, [Ru(bpy)(2)(dhipH3)](ClO4)(2) (in which bpy=2,2'-bipyridine, dhipH(3)=3,4-dihydroxy-imidado[4,5-f][1,10]-phenanthroline), was synthesized and characterized, and the pH effect on the emission spectra of the complex was studied. The interaction of the complex with calf thymus DNA was investigated by UV-visible and emission spectroscopy, and viscosity measurements. The results suggest that the complex acted as a sensitive luminescent pH sensor and a strong ct-DNA intercalator with an intrinsic binding constant of (4.0+/-0.7) x 10(5) M(-1) in buffered 50 mM NaCl.     

Immunosuppression in human peripheral blood T lymphocytes by fluvastatin

Statins are competitive inhibitors of HMG-CoAreductase, which is the major rate-limiting enzyme thatcontrols the conversion of HMG-CoA to mevalonic acid[1]. Mevalonate derived intermediates, such as isoprenoid,farnyesylpyrophosphate and geranylpyrophosphate, serveas important lipid attachments for the posttranslationalmodification of a variety of proteins such as small GTP-binding proteins of the Ras and Rho superfamily involvedin intracellular signaling [2]. Therefore, apart from the we…     

播种季节对玉米生长发育及干物质生产和分配的影响

1996－1997年,在蒙自坝对春、夏、秋、冬四季玉米的生长发育和干物质生产与分配进行了系统研究,结果表明：1冬玉米生育最长达171天,而夏玉米只有101天。2．春玉米花丝期的生产了较多的干物质,其它的则是花线期后生产的干物质更多,干物质生产量与日照时数和LAI的乘积正相关。3．灌浆期籽粒重占总增重的比例与各季玉米灌浆期≥10℃的积温正相关。4．春玉米籽生产除灌浆期的光合产物外,动用了前期贮存物的11．1％,其他玉米完全依赖于灌浆期的光合产物,并且不同比例光合产物贮存于营养体中。说明其玉米的产量受限于灌浆期的光合产物,其它玉米则受库容小或运输不畅的限制。     

基于Maxent的大洋臀纹粉蚧和南洋臀纹粉蚧在中国的适生区分析

大洋臀纹粉蚧Planococcus minor Maskell和南洋臀纹粉蚧P.lilacinus Cockerell是我国有重要检疫意义的有害生物。这两种粉蚧从东盟进口水果口岸检疫中频繁截获,且已在广东、海南、云南等地发现大洋臀纹粉蚧入侵,这对我国热带、亚热带的水果和观赏植物等已构成严重威胁。本研究以大洋臀纹粉蚧和南洋臀纹粉蚧在国内外的分布数据为基础,利用Maxent生态位模型和Arc GIS对两种粉蚧在中国的潜在适生区进行预测。预测结果表明,大洋臀纹粉蚧和南洋臀纹粉蚧的适生区主要分布在长江流域以南地区,其适生区面积分别占全国面积的22.14%、18.17%,其中高度适生区域集中分布在广西、广东、云南、福建、四川、台湾、海南等地区,与我国热带水果的主要种植区域具有高度的一致性。大洋臀纹粉蚧已成功入侵,一旦南洋臀纹粉蚧传入便可迅速扩散蔓延,并对我国热带水果生产造成严重危害。因此,各口岸应加强对东盟进口水果的检验检疫,预防其新的进入和扩散。