Screening of rice cultivars for Cr-stress response by using the parameters of seed germination,morpho-physiological and antioxidant analysis

Rice is the most important crop for the majority of population across the world with sensitive behavior toward heavy metals such as chromium (Cr) in polluted regions. Although, there is no information on the Cr resistance phenotyping in rice. Herein, two different groups of rice cultivars (normal, and hybrid) were used, each group with 14 different rice cultivars. Firstly, seed germination analysis was conducted by evaluating various seed germination indices to identify the rice cultivars with greatest seed germination vigor. Furthermore, exposure of chromium (Cr) toxicity to 28 different rice varieties (NV1-NV14, HV1-HV14) caused noticeable plant biomass reduction. Subsequently, NV2, NV6, NV10, NV12, NV13 (normal type), HV1, HV4, HV8, and HV9 (hybrid types) were pragmatic as moderately sensitive varieties, while NV3, NV4, NV9, and NV14 (normal type), HV3, HV6, HV7, and HV13 were observed as moderately tolerant. Although, NV7, and HV10 were ranked most sensitive cultivars, and NV11, and HV14 were considered as most tolerant varieties as compared to the other rice (both groups) genotypes. Afterward, Cr induced reduction in chlorophyll pigments were significantly lesser in HV14 relative to NV11, NV7, and especially HV10, and as a result HV14 modulated the total soluble sugar level as well as reduced ROS accumulation, and MDA contents production by stimulating the antioxidant defense mechanism conspicuously which further reduced the electrolyte leakage as well. Our outcomes provide support to explore the Cr tolerance mechanism in cereal crops as well as knowledge about rice breeding with increased tolerance against Cr stress.     

GST pull-down验证流感病毒PB1-F2蛋白与热休克蛋白40的相互作用

为体外验证流感病毒PB1-F2与热休克蛋白Hsp40相互作用,通过两个方向的GST pull-down试验验证PB1-F2与Hsp40的相互作用。构建GST-多肽融合蛋白原核表达载体pGEX-6P-1-PB1-F2和pGEX-6P-1-Hsp40,并在大肠杆菌(E.co-li)BL21中诱导表达;构建真核表达载体pLEGFP-Hsp40及pCAGGS-PB1-F2,并分别转染293T细胞使其表达Hsp40及PB1-F2融合蛋白,然后进行GST pull-down试验验证二者的相互作用。成功地构建了两种蛋白的各种表达载体,经表达、纯化获得了可溶性的GST-多肽融合蛋白,GST pull-down试验正反两方向都证实了PB1-F2与Hsp40的相互作用,初步证实了流感病毒PB1-F2在体外能与Hsp40发生相互作用。     

红豆杉(Taxus chinensis (Pilger) Rehd.)化学成分研究(简报)

自七十年代发现了紫杉醇（taxol）独特的抗癌机制一促进微管蛋白聚合、抑制微管蛋白解聚后,紫杉醇及其类似物紫杉烷类二该化合物的资源调查和化学研究倍受重视。紫杉醇主要存在于红豆杉科的大多数植物中,红豆杉科（Taxaceae）红豆杉属（TaxuS）植物全球大约有11种,我国有4种和1个变种。我们从采自湖北神农架的红豆杉（Tchinens周树皮中分离得到8个结晶性物质,本文报道其中已鉴定的3个成分,即taxinineJ（l）,ldiydroxybaccatinl（2）和taxol（3）。据文献报道,已经从红豆杉分离得到二十多种紫杉烷类化合物l'l,而我们分离得到的1和2…     

黑曲霉突变株葡萄糖淀粉酶的化学组成及其光谱学性质

黑曲霉突变株葡萄糖淀粉酶中一型GAI舍糖量为17.6%。氨基酸分析表明,天门冬氨酸和谷氨酸(包括酰胺)占20.3%,苏氨酸和丝氨酸占25.1%,三种碱性氨基酸占6%。紫外光谱在278nm和250nm处分别有最大和最小吸收;其荧光光谱的最大激发波长和发射波长分别为284nm与342nm;远紫外CD谱表现为一双负峰;在溶液中的构象是α-螺旋10.6%,β折叠16.3%和无规卷曲73.1%。     

Cell-surface expression of a membrane-anchored form of the human chorionic gonadotropin alpha subunit

We carried out experiments designed to generate a novel cell-surface protein from a small glycosylated secretory protein. DNA encoding the entire precursor of human chorionic gonadotropin (hCG, alpha subunit) was fused precisely to DNA encoding the transmembrane and cytoplasmic domains of the vesicular stomatitis virus glycoprotein. When expressed in animal cells this DNA encoded the 92-amino acid hCG-alpha subunit anchored in cellular membranes by an extension composed of the 49 carboxyl-terminal amino acids of vesicular stomatitis virus glycoprotein. This hybrid protein was transported efficiently to the plasma membrane of animal cells. The two asparagine-linked glycans on the anchored form of hCG-alpha were large and heterogeneous when compared to those on the secretory form. Experiments employing in vitro mutagenesis and the glycosylation inhibitor tunicamycin established that the presence of at least one of the two asparagine-linked glycans was required for expression of the anchored molecule on the cell surface. However, as reported previously, secretion of hCG-alpha occurred in the absence of glycosylation. Also, mutations eliminating the second glycosylation site (at amino acid 78) in both the anchored or secreted forms apparently led to partial denaturation or a conformational change interfering with transport of the protein.     

Litterfall Production Along Successional and Altitudinal Gradients of Subtropical Monsoon Evergreen Broadleaved Forests in Guangdong, China

Evaluation of litterfall production is important for understanding nutrient cycling, forest growth, successional pathways, and interactions with environmental variables in forest ecosystems. Litterfall was intensively studied during the period of 1982–2001 in two subtropical monsoon vegetation gradients in the Dinghushan Biosphere Reserve, Guangdong Province, China. The two gradients include: (1) a successional gradient composed of pine forest (PF), mixed pine and broadleaved forest (MF) and monsoon evergreen broadleaved forest (BF), and (2) an altitudinal gradient composed of Baiyunci ravine rain forest (BRF), Qingyunci ravine rain forest (QRF), BF and mountainous evergreen broadleaved forest (MMF). Mean annual litterfall production was 356, 861 and 849 g m⁻² for PF, MF and BF of the successional gradient, and 1016, 1061, 849 and 489 g m⁻² for BRF, QRF, BF and MMF of the altitudinal gradient, respectively. As expected, mean annual litterfall of the pioneer forest PF was the lowest, but rapidly increased over the observation period while those in other forests were relatively stable, confirming that forest litterfall production is closely related to successional stages and growth patterns. Leaf proportions of total litterfall in PF, MF, BF, BRF, QRF and MMF were 76.4%, 68.4%, 56.8%, 55.7%, 57.6% and 69.2%, respectively, which were consistent with the results from studies in other evergreen broadleaved forests. Our analysis on litterfall monthly distributions indicated that litterfall production was much higher during the period of April to September compared to other months for all studied forest types. Although there were significant impacts of some climate variables (maximum and effective temperatures) on litterfall production in some of the studied forests, the mechanisms of how climate factors (temperature and rainfall) interactively affect litterfall await further study.     

The inhibitory effect of BSP-A1/-A2 on protein kinase C and tyrosine protein kinase

Bovine seminal plasma contains a group of similar proteins, namely BSP-A1, BSP-A2, BSP-A3, and BSP-30-kDa (collectively called BSP proteins), and they are secreted by the seminal vesicles. In our study, we purified the BSP-A1/-A2 through affinity chromatography and found for the first time that BSP-A1/-A2 can inhibit the activity of protein kinase C (PKC) and tyrosine protein kinase (TPK). The inhibition was dose dependent. When the PKC and TPK activities are expressed as the logarithm of percentage activity taking the activity in the absence of the BSP-A1/-A2 as 100%, there is a linear relationship between the their activities and the dose of BSP-A1/-A2.     

人参总皂苷对人红白血病细胞株（K562）中STAT5表达的影响

旨在探讨人参总皂苷对K562细胞STAT5表达的影响.MTT法显示TSPG对K562细胞增殖抑制程度呈剂量与时间依赖性增加,且呈正相关关系.流式细胞术表明TSPG能阻止K562细胞从G0/G1期向S、G2/M期移行.激光共聚焦显微镜观察可见,TSPG 200 mg/L作用K562细胞24 h,胞浆中的STAT5荧光强度增加,而胞核内STAT5荧光强度减弱.Western blotting结果显示,TSPG作用K562细胞6 、24 、48 h,胞核中STAT5表达较对照组减少,TSPG作用72 h胞核蛋白中STAT5表达增加;TSPG作用K562细胞6 、12、24、48、72 h,胞浆内STAT5表达增加.TSPG能减少K562胞核中STAT5的表达,这可能是TSPG抑制K562细胞增殖的作用机制之一.     

药用植物北五味子的组织培养

取北五味子带腋物嫩茎作为植体,培养于附加同种类和浓度激素的ＭＳ培养基上,在附国加６－ＢＡ２．０＋ＺＴ０．１ｍｇ／Ｌ时,诱导芽的效果最佳;在附加６～ＢＡ２．０＋ＮＡＡ０．２＋ＺＴ０．１ｍｇ／Ｌ时,芽的增殖率最好,在附加ＮＡＡ０．２ｍｇ／Ｌ时,生根效果最佳,当苗高２．０～２．５ｃｍ根数达３－５条时,开瓶锻炼２天,移栽于消过毒的土壤中,１０天后,成活率达１００％。