拟南芥PGK基因家族功能的初步分析

磷酸甘油酸激酶(Phosphoglycerate kinase)是一类进化上非常保守的蛋白家族,因而利用模式植物拟南芥研究PGK家族基因功能具有普遍意义。拟南芥基因组中含有三个PGK基因家族成员(PGK1,PGK2和PGK3),但是对于它们的基因表达模式和蛋白定位的研究还不是很清楚。本文利用实时荧光定量PCR技术检测了PGK基因家族的表达模式,结果表明三个PGK基因在拟南芥的各个组织器官和发育阶段中都有表达。利用拟南芥原生质体瞬时转化系统对三个PGK蛋白进行亚细胞定位,结果显示PGK1和PGK3定位于细胞基质,而PGK2定位于叶绿体。另外,我们分离得到了PGK2基因的T-DNA插入敲除突变体pgk2。pgk2在正常条件下表现出叶片黄化,PR1基因上调表达和H_2O_2过量积累等类似于超敏反应的细胞死亡表型。进一步的遗传分析表明pgk2的细胞死亡表型和T-DNA插入位点紧密连锁,暗示着pgk2的细胞死亡表型是由于PGK2的基因缺失造成的,因此PGK2可能在调控植物细胞程序化死亡过程中有重要作用。以上研究结果对于进一步探讨PGK基因家族的功能具有重要的参考价值。     

拟南芥SGR2基因参与叶绿素降解和衰老过程

[目的]研究拟南芥SGR2基因参与叶绿素降解和衰老过程。[方法]购得SGR2(stay green rice,水稻滞绿基因)基因的T-DNA插入突变体,并进行叶绿素荧光分析、叶绿素含量和可溶性总糖测定、qRT-PCR等试验以及生物信息学分析。[结果]突变体叶绿素a含量较WT(colo-0野生型)降低;可溶性糖含量高于WT;RBCS(Rubisco,核酮糖1,5-二磷酸羧化酶/加氧酶的小亚基)和CAB(Chl a binding protein,叶绿素a结合蛋白)基因表达下调。而突变体开花明显比野生型延迟。[结论]证明了SGR2基因参与了拟南芥叶绿素降解和衰老过程。     

Arabidopsis kin help keep genetics studies all in the family

An unobtrusive weed often found at roadsides and other disturbed sites, Arabidopsis thaliana has risen from its humble roots to become the model organism, or "lab rat," for studying plant molecular biology. Now, by comparing the genetic makeup and characteristics of A. thaliana to its cousins, evolutionary biologists can discern how the plant has changed through time.     

拟南芥和水稻cystatin基因家族的生物信息学分析

利用已经分离的植物半胱氨酸蛋白酶抑制剂(cystatin)基因的cystatin结构域为检索序列在基因组水平上对拟南芥和水稻中的cystatin基因家族的成员进行分析;同时利用这些基因编码的蛋白质序列构建系统发生树,并对这些蛋白序列的保守序列进行分析;最后在GenBank的EST数据库中查找这些基因的ESTs表达序列。结果表明:1结合结构域的鉴定、多序列联配以及MEME分析最终确定了7个拟南芥和11个水稻的cystatin基因。2系统发生分析表明,cystatin基因的基本特征很可能是在拟南芥和水稻的分离之前就已经形成。3 cystatin结构域在蛋白质间高度保守。4拟南芥和水稻的cystatin基因主要在花、叶、根、种子和愈伤组织中表达,这有助于植物避免昆虫的侵害。     

拟南芥转酮醇酶Transket结构域家族基因的鉴定和生物信息学分析

植物转酮醇酶是植物光合作用中的重要酶类,在卡尔文循环中起着关键作用。本研究利用HMMER程序,对拟南芥转酮醇酶Transket的家族成员进行鉴定,获得了12个Transket家族成员,其中AT3G60750是一个植物光合作用的关键基因。利用MapInspect绘制了各家族成员的染色体定位图谱。利用生物信息学方法对拟南芥芯片信息数据进行了分析,获得了各家族成员在不同组织中的表达模式。本研究结果将为揭示此类蛋白参与植物体内的生理过程及分子机制有着重要的借鉴意义和参考价值。     

Somatic Instability Caused by a Cysteine-Sensitive Gene in Arabidopsis

A recessive gene immutans (im) is responsible for abnormal chloroplast development which results in variegation in Arabidopsis plants. Somatic mutability is simulated, though only functional disorder is involved. Cysteine and low temperature favor normal function, while homocysteine interferes with chloroplast development without producing an adverse effect on the growth of the mutant.     

Regulation of influenza virus infection by microRNAs

MicroRNAs(miRNAs) are small noncoding RNAs of 18–25 nucleotides(nt) in length that represent key regulators of many normal cellular functions through the inhibition of mRNA translation and mRNA degradation. To date, over 2 500 mature miRNAs have been identified in plants, animals and several types of viruses. Influenza A virus(IAV), which is a negativesense, single-stranded RNA virus, does not encode viral miRNA. However, IAV infection can alter the expression of host miRNAs, either in cell culture or in host. In turn, host miRNAs regulate IAV life cycle through directly binding to IAV genome or indirectly targeting host factors associated with viral replication. In this review, we briefly summarized the role and significance of miRNA in relation to IAV pathogenesis. Understanding the role of cellular miRNAs during viral infection may be beneficial to the identification of novel therapeutic strategies to block IAV replication.     

一株邻苯二甲酸酯降解菌降解特性研究

测定了从巢湖底泥中筛选的活性菌株皮氏伯克霍尔德氏菌(Burkholderia pickettii)对4种邻苯二甲酸酯(PAEs)的降解.结果表明,Burkholderia pickettii菌对4种混合体系PAEs的降解速率常数高于降解单一种类PAEs,不同化学结构的邻苯二甲酸酯生物降解能力不同,PAEs浓度、温度和pH都是影响PAEs生物降解的主要因素,各因素对PAEs降解影响的大小关系是温度＞PAEs浓度＞pH,各因素最优水平组合应是浓度为20 mg·L-1,pH值为7,温度30℃.     

一株邻苯二甲酸酯降解菌降解特性研究

测定了从巢湖底泥中筛选的活性菌株皮氏伯克霍尔德氏菌(Burkholderia pickettii)对4种邻苯二甲酸酯(PAEs)的降解。结果表明,Burkholderia pickettii菌对4种混合体系PAEs的降解速率常数高于降解单一种类PAEs,不同化学结构的邻苯二甲酸酯生物降解能力不同,PAEs浓度、温度和pH都是影响PAEs生物降解的主要因素,各因素对PAEs降解影响的大小关系是温度>PAEs浓度>pH,各因素最优水平组合应是浓度为20 mg.L-1,pH值为7,温度30℃。     

有机磷降解剂对生菜农残降解效果分析

[目的]分析有机磷降解剂对生菜农残的降解效果.[方法]使用酶抑制分光光度法,以紫茎泽兰、秸秆为原料制备有机磷降解剂,检测其对生菜乐果的降解效果.[结果]不同pH的紫茎泽兰酶降解剂、秸秆酶降解剂对生菜中的有机磷有明显的降解作用,降解率高达79.34％～81.91％.[结论]该研究可为开发新型的有机磷降解剂提供理论依据.     

Insensitivity to Ethylene Conferred by a Dominant Mutation in Arabidopsis thaliana

Ethylene influences a number of developmental processes and responses to stress in higher plants. The molecular basis for the action of ethylene was investigated in mutants of Arabidopsis thaliana that have altered responses to ethylene. One mutant line, which has a dominant mutation at a locus designated etr, lacks a number of responses to ethylene that are present in the wild-type plant. These include inhibition of cell elongation, promotion of seed germination, enhancement of peroxidase activity, acceleration of leaf senescence, and feedback suppression of ethylene synthesis by ethylene. These diverse responses, which occur in different tissues of Arabidopsis, appear to share some common element in their transduction pathways-for example, a single receptor for ethylene. Results of ethylene binding experiments in vivo indicate that this receptor may be affected by the etr mutation.     

粘土矿物固定化微生物对土壤中阿特拉津的降解研究

以粘土矿物为载体,采用吸附挂膜法对已筛选的阿特拉津降解菌株进行固定化,并应用固定化微生物降解土壤中的阿特拉津.结果表明,该菌株在粘土矿物上生长良好,根据菌种生理生化特性、环境扫描电镜图片以及16SrDNA基因的相似性分析初步鉴定该菌株为Ochrobactrum sp..接种降解菌能明显加快阿特拉津在土壤中的降解速率,粘土矿物固定化微生物的降解效果要明显优于游离菌,粘土矿物粒径越小,固定化微生物的降解效果越好,纳米粘土矿物同定化微生物的降解效果要好于原粘土矿物.用一级动力学方程描述阿特拉津在土壤中的降解过程,不同土壤中阿特拉津的降解速率不同.阿特拉津在红壤、砂姜黑土、黄褐土中的降解半衰期(t1/2)分别为36.9、49.1、55.0 d,投加纳米蒙脱石固定化降解菌后的半衰期则分别为16.3、25.3、21.7 d.     

氯氰菊酯的酶促降解

阴沟肠杆菌w 10 j15经过纯培养、超声波破碎和高速离心,提取到氯氰菊酯降解酶。在实验条件下测定了降解酶对氯氰菊酯的降解特性。结果表明,降解酶在40℃、pH 7.5时对氯氰菊酯显示最大的降解活性,对氯氰菊酯的降解率为78%;它在30~50℃或pH 6.5~8.0稳定性良好。L inew eaver-Burg法做图分析表明,其酶蛋白最大降解速率Vm ax为63.69 nm o.lmL-1.m in-1,米氏常数(Km)为377.35 nm o l/mL。     

Control of genic DNA methylation by a jmjC domain-containing protein in Arabidopsis thaliana

Differential cytosine methylation of repeats and genes is important for coordination of genome stability and proper gene expression. Through genetic screen of mutants showing ectopic cytosine methylation in a genic region, we identified a jmjC-domain gene, IBM1 (increase in bonsai methylation 1), in Arabidopsis thaliana. In addition to the ectopic cytosine methylation, the ibm1 mutations induced a variety of developmental phenotypes, which depend on methylation of histone H3 at lysine 9. Paradoxically, the developmental phenotypes of the ibm1 were enhanced by the mutation in the chromatin-remodeling gene DDM1 (decrease in DNA methylation 1), which is necessary for keeping methylation and silencing of repeated heterochromatin loci. Our results demonstrate the importance of chromatin remodeling and histone modifications in the differential epigenetic control of repeats and genes.     

Cleavage of Arabidopsis PBS1 by a bacterial type III effector

Plant disease-resistance (R) proteins are thought to function as receptors for ligands produced directly or indirectly by pathogen avirulence (Avr) proteins. The biochemical functions of most Avr proteins are unknown, and the mechanisms by which they activate R proteins have not been determined. In Arabidopsis, resistance to Pseudomonas syringae strains expressing AvrPphB requires RPS5, a member of the class of R proteins that have a predicted nucleotide-binding site and leucine-rich repeats, and PBS1, a protein kinase. AvrPphB was found to proteolytically cleave PBS1, and this cleavage was required for RPS5-mediated resistance, which indicates that AvrPphB is detected indirectly via its enzymatic activity.     

超高效液相色谱法测定拟南芥芥子油苷

将已有的拟南芥芥子油苷高效液相色谱(HPLC)检测方法转换为超高效液相色谱(UPLC)方法,通过条件优化改进,建立拟南芥芥子油苷UPLC检测方法。该方法采用Waters ACQUITY UPLC HSS T3色谱柱(50 mm×2.1 mm,1.8μm),以超纯水和甲醇为流动相进行梯度洗脱,流速为0.40 mL·min-1,检测波长229 nm,进样量5μL,内标为苯甲基芥子油苷。利用此方法测得样品的日内和日间精密度均小于9.62%,用此方法与HPLC法测定生长10周的拟南芥莲座叶中各种芥子油苷组分含量一致。方法简单、快速、准确,适用于拟南芥芥子油苷组分及含量的分析。     

酶联免疫吸附法分析鬼臼毒素在水体中的降解

利用固相间接竞争酶联免疫吸附法（Indirect competitive enzyme—linked immunosorbent assay，IC—ELISA）对鬼臼毒素在不同pH值水体中的稳定性进行了研究，并以高效液相色谱法（HPLC）进行验证。结果表明：鬼臼毒素在酸性条件下稳定，半衰期约为145d；在中性条件下，半衰期约为10d；在碱性条件下降解速度快，半衰期仅为5．78h。IC—ELISA法和HPLC法测得鬼臼毒素在pH为5．0、7．0水体中的水解半衰期结果相似，但IC—ELISA法检测灵敏度更高，且具有处理量大，方便快速等优点。因此，在一定条件下IC—ELISA法可用于水体中鬼臼毒素含量的测定。根据鬼臼毒素的水溶性、Koc系数及半衰期等判定，鬼臼毒素是不会给水体带来严重污染的。