禽病原性大肠杆菌iro和tsh基因缺失株的构建

通过SSH和SCOTS研究, 铁系统(Iro)和温度敏感性血凝素(Tsh)在禽病原性大肠杆菌(APEC)的感染中可能发挥重要作用。基因检测发现, 在243个禽源大肠杆菌分离株中, 有205株为iro+菌株, 其中高、中度和低致病株分别为89.8%(184/205)、8.8%(18/205)和1.5%(3/205); 有167株为tsh+菌株, 高、中度、低致病株分别为87.4%(146/167)、12.6%(21/167)和0%(0/167), 结果显示iro+或tsh+株大多数为高致病株。为了确定iro和tsh基因在APEC致病力中的作用, 以APEC E037株为基础, 通过自杀性载体分别构建了iro和tsh基因缺失突变株E037(Δiro)、E037(Δtsh)和E037(ΔiroΔtsh)。动物感染性试验表明, 突变株在鸡体内的繁殖能力和致病性均明显下降, 但两个基因的协同致病作用不显著。进一步证实Iro和Tsh为APEC重要的致病因子。     

Complete genome sequence of the bacterium Ketogulonicigenium vulgare Y25

Ketogulonicigenium vulgare is characterized by the efficient production of 2KGA from L-sorbose. Ketogulonicigenium vulgare Y25 is known as a 2-keto-L-gulonic acid-producing strain in the vitamin C industry. Here we report the finished, annotated genome sequence of Ketogulonicigenium vulgare Y25.     

木质纤维素酶高产菌株的筛选及其对玉米秸秆降解效果的影响

为了提高玉米秸秆中木质素的降解率,从腐烂的树枝和土壤中筛选木质纤维素酶高产菌株,以秸秆为唯一C源富集培养后,采用PDA-愈创木酚法进行初筛,筛选出产木质素酶真菌5株,然后以玉米秸秆为主要C源进行固态发酵和复筛。结果表明:第5号菌株在发酵玉米秸秆5 d后,使木质素的降解率达到最高(34.95%),粗纤维的降解率达到20.00%,显著高于其他4种菌株(P<0.05),其羧甲基纤维素酶比酶活达到116.35 U/g;10 d后,其木质素酶比酶活达到最高(45.64 U/g)。     

氮磷钾配施对填充型烤烟烟碱含量的影响

以东北填充型烤烟品种"龙江911"为试验材料,通过正交回归田间试验,建立了氮、磷、钾肥与烤烟上部叶片烟碱含量的回归效应模型,并对各因子和交互作用进行了分析,模拟计算得出以降低上部叶片烟碱含量为目标的优化施肥方案.对模型解析表明,随施氮量增加,上部叶片烟碱含量呈先上升后下降趋势;随施磷量增加,烟碱含量呈上升趋势;随施钾量增加,烟碱含量呈急剧下降趋势.双因素效应大小依次为:氮钾＞磷钾＞氮磷,在一定范围内,氮磷、磷钾与烟碱含量表现为负相关,存在拮抗作用;而氮钾则相反,存在促进作用.对氮、磷、钾肥与烤烟上部叶片烟碱含量模型的综合分析得出:在植烟土壤为河淤土的生产区,烟田的基础施肥量建议为:氮肥33.5～47.8kg·hm-2,磷肥40.2～63.6 kg·hm-2,钾肥78.0～119.6kg·hm-2.     

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。     

低氧及酸化胁迫对大黄鱼幼鱼离子调节与鳃组织结构的影响

为探讨大黄鱼幼鱼在低氧及酸化胁迫下机体离子调节情况,本研究探讨了低氧(溶解氧量DO 3.5 mg·L-1,pH 8.1)、酸化(DO 7.0 mg·L-1,pH 7.35)以及低氧酸化协同胁迫(DO3.5 mg·L-1,pH 7.35)对大黄鱼幼鱼鳃组织结构以及离子调节相关生理指标的影响.结果 表明:低氧胁迫下,大黄鱼...