Structures and magnetic properties of mono-doped fullerenes C59Xn and C59X(6mn)m (X=Bm,N+, P+, As+, Si): isoelectronic analogues of C60 and C60(6m)

Structures of mono-doped fullerenes, C59Xn and C59X(6mn)m (X=Bm, N+, P+, As+, Si), the isoelectronic analogues to C60 and C606m with 60 and 66 pi-electrons, have been investigated at the B3LYP/6-31G* level of density functional theory. On the basis of the computed nucleus independent chemical shifts (NICS) at the cage center and also at the center of individual rings as magnetic criteria, heterofullerenes with 60 pi-electrons are as aromatic as the parent C60, while those with 66 pi-electrons are much less aromatic than C606m. The very distinct endohedral chemical shifts of the 66 pi-electron systems may be useful to identify the heterofullerenes through their endohedral 3He NMR chemical shifts.     

木薯果胶甲基酯酶抑制因子MePMEI1的生物信息学分析

为探讨木薯MePMEI1的分子结构特征。通过PCR扩增和测序技术及生物信息学分析工具对木薯MePMEI1基因进行克隆、测序及相关生物信息学分析。结果表明木薯MePMEI1基因编码区全长609 bp,编码202个氨基酸残基;MePMEI1基因编码蛋白分子量21.78 k D,理论等电点(pI)约为5.51;生物信息学预测发现,木薯MePMEI1蛋白是稳定的亲水蛋白;具有跨膜区为分泌蛋白;含有1个PMEI结构域,1个糖基化位点,31个磷酸化位点;二、三级结构以α螺旋和无规则卷曲为主。该蛋白的生物功能可能与细胞被膜、酶和生长因子等相关。木薯MePMEI1基因的生物信息学分析为进一步研究其遗传特性和生理生化机制提供了理论依据。     

幽门螺杆菌HspA融合蛋白口服疫苗的构建

构建表达幽门螺杆菌的保护性抗原分热休克蛋白A亚单位(HspA）和霍乱毒素B亚单位（CtxB）的重组融合蛋白的生物工程菌株,以此制备幽门螺杆菌的口服疫苗。用PCR方法扩增hspA和ctxB两个目的的基因片段,将它们分别克隆至pSK（＋）质粒上,然后插入含T7启动子ET－22b（＋）的表达载体中,构建嗓基因的表达质量pET－hct,转化E.coliBL21(DE3）,经IPTG诱导表达融合蛋白HCT。经测序,hspA-ctxB(hct)融合基因片段由726bp组成,可以编码242个氨基酸残基的多肽。经SDS－PAGE和免疫印迹分析检测发现,融合基因表达的蛋白质相对分子质量约为30kD。融合蛋白经镍离子柱纯化、复性后,和HspA共同标记同位素^125I,然后给小鼠灌胃,结果观察到HCT组小鼠血清中的^125I的放射量要明显高于HspA组（P＜0．001）,且吸收峰值时间明显提前。融合蛋白中的CtxB可明显促进小鼠对HspA的吸收,HCT融合蛋白可以作为预防和治疗幽门螺杆菌感染的侯选口服疫苗。     

Nuclear retention of the lncRNA SNHG1 by doxorubicin attenuates hnRNPC–p53 protein interactions

The protein p53 plays a crucial role in the regulation of cellular responses to diverse stresses. Thus, a major priority in cell biology is to define the mechanisms that regulate p53 activity in response to stresses or maintain it at basal levels under normal conditions. Moreover, further investigation is required to establish whether RNA participates in regulating p53's interaction with other proteins. Here, by conducting systematic experiments, we discovered a p53 interactor—hnRNPC—that directly binds to p53, destabilizes it, and prevents its activation under normal conditions. Upon doxorubicin treatment, the lncRNA SNHG1 is retained in the nucleus through its binding with nucleolin and it competes with p53 for hnRNPC binding, which upregulates p53 levels and promotes p53‐dependent apoptosis by impairing hnRNPC regulation of p53 activity. Our results indicate that a balance between lncRNA SNHG1 and hnRNPC regulates p53 activity and p53‐dependent apoptosis upon doxorubicin treatment, and further indicate that a change in lncRNA subcellular localization under specific circumstances is biologically significant.     

三角酵母D—氨基酸氧化酶基因的克隆,测序及表达

利用跨越内含子的ＰＣＲ技术,从三角酵母（Ｔｒｉｇｏｎｏｐｓｉｓｖａｒｉａｂｉｌｉｓ）变种ＦＡ１１０中扩增得到Ｄ氨基酸氧化酶基因（ｄａａｏ）,并通过ＴＡ克隆的方法将其克隆至ｐＧＥＭＴ载体。序列测定结果表明,所得ｄａａｏ基因的５′端内含子已被删除,基因总长度为１０７１ｂｐ,它与Ｔｒｉｇｏｎｏｐｓｉｓｖａｒｉａｂｉｌｉｓ的Ｄ氨基酸氧化酶同源性达９８３％,与Ｆｕｓａｒｉｕｍｓｏｌａｎｉ和Ｒｈｏｄｏｔｏｒｕｌａｇｒａｃｉｌｉｓ的同源性分别是３８９％和３０８％。为提高表达水平,又将此基因转移至高表达载体ｐＥＴ２８ｂ上,在大肠杆菌ＢＬ２１（ＤＥ３）中进行诱导表达。经ＩＰＴＧ诱导,目的蛋白的产生量可占菌体总蛋白量的４６％,分子量约为３８ｋＤ。Ｄ氨基酸氧化酶的活力可达８０２ｕ／Ｌ。     

南京城市公园绿地不同植被类型土壤呼吸的变化

子2007年10月-2008年9月,利用Li-6400便携式光合作用仪配合土壤呼吸气室对南京中山植物园内草坪、疏林和近自然林3种植被类型的土壤呼吸速率的季节变化及其影响因子进行了测定.结果表明:不同植被类型土壤呼吸速率具有明显的季节变化,夏季(8月)较高,近自然林、疏林和草坪类型分别为3.28、4.07和7.58 μmol·m~(-2)·s~(-1),冬季(12月)最低,近自然林、疏林和草坪类型分别为0.82、0.99和1.42 μmol·m~(-2)·s~(-1);不同植被类型的年均土壤呼吸速率有显著差异(P＜0.05),平均土壤呼吸速率大小排序为草坪>疏林>近自然林;不同植被类型的土壤呼吸速率与土壤温度呈显著性指数相关关系,与土壤含水率无显著相关关系;Q_(10)值均随着土层深度的增加而增加;不同植被类型的Q_(10)值存在一定程度的差异,近自然林类型的Q_(10)值大于草坪和疏林类型的Q_(10)值.研究表明,城市如果大量发展草坪可能增加土壤CO_2的排放.

Abstract：

By using Li-6400 portable photosynthetic apparatus connected to soil chamber,the soil respiration rate under three vegetation types(lawn,open woodland,and close-to-nature forest)in Nanjing Zhongshan Botanical Garden was measured from October 2007 to September 2008,with related affecting factors analyzed.The soil respiration rate had obvious seasonal fluctuation,being the highest in summer(August)and the lowest in winter(December).For the close-to-nature forest,open woodland,and lawn,their soil respiration rate in summer was 3.28,4.07,and 7.58μmol·m~(-2)·s~(-1),and that in winter was 0.82,0.99,and 1.42μmol·m~(-2)·s~(-1),respectively.The annual mean soil respiration rate differed significantly with vegetation type(P＜0.05),which was in order of close-to-nature forest＜open woodland＜lawn.The soil respiration rate had significant exponential correlation with soil temperature,but no correlation with soil moisture.The Q_(10) value increased with increasing soil depth,and was larger in close-tonature forest than in open woodland and lawn.Our results indicated that the rapid development of lawn in urban green space could increase the urban soil CO_2 emission.     

拟南芥转录因子GRAS 家族基因群响应渗透和干旱胁迫的初步探索

GRAS家族是一类植物特有的转录调控因子, 已有报道表明该家族基因在植物生长发育和光信号转导过程中具有重要作用。目前在拟南芥(Arabidopsis thaliana)基因组中已鉴定了33个GRAS家族基因。利用功能基因组学和生物信息学手段,通过基因芯片数据挖掘和基因功能预测, 对拟南芥GRAS家族基因在渗透和干旱胁迫过程中的应答模式进行了初步探索, 提出了一类响应渗透胁迫和干旱胁迫的拟南芥GRAS家族基因。以SCL13为例, 利用基因芯片相关性和GO分析, 对其在渗透胁迫信号转导过程中可能的调控机制进行了预测和分析。这一研究将为阐明GRAS家族基因参与水分胁迫的分子机制提供新的思路, 同时也为植物抗逆分子育种提供候选基因。     

‘Tethering’ fragment-based drug discovery to identify inhibitors of the essential respiratory membrane protein type II NADH dehydrogenase

Energy generation is a promising area of drug discovery for both bacterial pathogens and parasites. Type II NADH dehydrogenase (NDH-2), a vital respiratory membrane protein, has attracted attention as a target for the development of new antitubercular and antimalarial agents. To date, however, no potent, specific inhibitors have been identified. Here, we performed a site-directed screening technique, tethering-fragment based drug discovery, against wild-type and mutant forms of NDH-2 containing engineered active-site cysteines. Inhibitory fragments displayed IC₅₀ values between 3 and 110?μM against NDH-2 mutants. Possible binding poses were investigated by in silico modelling, providing a basis for optimisation of fragment binding and improved potency against NDH-2.