摘要：
Chemoreception is a key feature in selection of host plant by phytophagous insects, and odorant-binding proteins (OBPs) are involved in chemical communication of both insects and vertebrates. The legume pod borer, Maruca vitrata Fabricius (Lepidoptera: Crambidae) is one of the key pest species of cowpea and widely distributed throughout tropical and subtropical regions, causing up to 80% of yield loss. In this study, we investigated the electrophysiological responses of female M. vitrata to floral volatiles from V. unguiculata. Seventeen electroantennogram-active compounds were identified from floral volatiles of V. unguiculata by coupled gas chromatography-electroantennography (GC-EAD) and gas chromatography-mass spectrometry (GC-MS). Then, we cloned two novel full-length GOBP genes (MvitGOBP1 and MvitGOBP2) from the antennae of M. vitrata using reverse transcription PCR. Protein sequence analysis indicated that they shared high sequence similarity with other Pyralididae insect GOBPs and had the typical six-cysteine signature. Real-time PCR analysis indicated that MvitGOBP1-2 mRNA was highly expressed in the antennae of female adult with several thousands-fold difference compare to other tissue. Next, the recombinant MvitGOBP1-2 was expressed in Escherichia coli and purified using Ni ion affinity chromatography. Fluorescence binding assays demonstrated that MvitGOBP1-2 had different binding affinities with 17 volatile odorant molecules including butanoic acid butyl ester, limonene, 4-ethylpropiophenone, 1H-indol-4-ol, butanoic acid octyl ester and 2-methyl-3-phenylpropanal. In the field trapping experiment, these six floral volatiles could effectively attract female moths and showed significant difference compared with the blank lure. These results suggested that MvitGOBPs and the seventeen floral volatiles are likely to function in the olfactory behavior response of female moths, which may have played crucial roles in the selection of oviposition sites. The six compounds that we have identified from the volatiles of V. unguiculata may provide useful information for exploring efficiency monitoring and integrated pest management strategies of this legume pod borer in the field.
作者机构：
[Huang Xue-Ying] Cent China Normal Univ, Coll Chem, Wuhan 430079, Peoples R China.;[Zhang Wei; Qi Chao; Liu Yan-Li; Lei Ming; Zhao Hao-Bin; Liu Ke] Cent China Normal Univ, Coll Life Sci, Hubei Key Lab Genet Regulat & Integrat Biol, Wuhan 430079, Peoples R China.;[Shen Yang] Univ Toronto, Struct Genom Consortium, Toronto, ON M5G 1L7, Canada.
通讯机构：
[Qi Chao] C;Cent China Normal Univ, Coll Life Sci, Hubei Key Lab Genet Regulat & Integrat Biol, Wuhan 430079, Peoples R China.
关键词：
鸟嘌呤核苷酸解离刺激因子(RalGDS);Ras 结合结构域(RBD);Ras 蛋白
摘要：
Ras结合结构域（RBD）是鸟嘌呤核苷酸解离刺激因子（Ral GDS）家族成员C-端的高保守区,通过它连接Ras和Ras相关蛋白。利用Red Wings和SGC-1 screens相关的悬滴法设盘结晶,按体积比1∶1加蛋白液到含1∶100胞内蛋白酶Glu-C（w/w）的结晶溶液（2 mol/L（NH4）2SO4,0.2 mol/L Na Ac,0.1 mol/L HEPES,5%MPD,p H 7.5）中,晶体3天长成可组装大小。利用X-射线晶体衍射技术解析了人Ral GDS的Ras结合域（Ral GDS-RBD）的晶体结构,对比鼠和人Ral GDS-RBD,主要是Ras结合区的C-端不同。人Ral GDS-RBD通过Glu838和Glu840在Ral GDS和Ras蛋白间形成氢键,而在同一位点,鼠Ral GDS-RBD通过Asp820和Asp822形成氢键。人Ral GDS-RBD结构中含ββαββαβ-型三维结构的泛素样构象,一个单体的C-端残基与相邻单体的β折叠形成平行βββββ结构。
作者机构：
[Liu, Kaiyu; Peng, Jianxin; Ma, Haihao; Peng, Rong; Ma, Yuemin] Cent China Normal Univ, Sch Life Sci, Wuhan, Peoples R China.;[Liu, Xuehui; Xu, Pingyong] Chinese Acad Sci, Inst Biophys, Natl Lab Biomacromol, Beijing 100080, Peoples R China.;[Lan, Que; Dyer, David H.] Univ Wisconsin, Coll Agr & Life Sci, Dept Biochem & Entomol, Madison, WI 53706 USA.;[Hong, Huazhu] Wuhan Inst Bioengn, Sch Life Sci, Wuhan, Peoples R China.
通讯机构：
[Peng, Jianxin] C;Cent China Normal Univ, Sch Life Sci, Wuhan, Peoples R China.
摘要：
The cotton bollworm, Helicoverpa armigera, has developed strong resistance to many insecticides. Sterol Carrier Protein-2 (SCP-2) is an important non-specific lipid transfer protein in insects and appears to be a potential new target. In order to elucidate the structure and function of Helicoverpa armigera SCP-2 (HaSCP-2), NMR spectroscopy, docking simulations, mutagenesis and bioassays were performed. HaSCP-2 composed of five α-helices and four stranded β-sheets. The folds of α-helices and β-sheets interacted together to form a hydrophobic cavity with putative entrance and exit openings, which served as a tunnel for accommodating and transporting of lipids. Several sterols and fatty acids could interact with HaSCP-2 via important hydrophobic sites, which could be potential targets for insecticides. Mutagenesis experiments indicated Y51, F53, F89, F110, I117 and Q131 may be the key functional sites. HaSCP-2 showed high cholesterol binding activity and SCP-2 inhibitors (SCPIs) could inhibit the biological activity of HaSCP-2. SCPI-treated larvae at young stage showed a significant decrease of cholesterol uptake in vivo. Our study describes for the first time a NMR structure of SCP-2 in lepidopteran H. armigera and reveals its important function in cholesterol uptake, which facilitates the screening of effective insecticides targeting the insect cholesterol metabolism.
摘要：
Dynamic chromatin structure is modulated by post-translational modifications on histones, such as acetylation, phosphorylation and methylation. Research on histone methylation has become the most flourishing area of epigenetics in the past fourteen years, and a large amount of data has been accumulated regarding its biology and disease implications. Correspondingly, a lot of efforts have been made to develop small molecule compounds that can specifically modulate histone methyltransferases and methylation reader proteins, aiming for potential therapeutic drugs. Here, we summarize recent progress in chemical probe and drug discovery of histone methyltransferases and methylation reader proteins. For each target, we will review their biological/biochemical functions first, and then focus on their disease implications and drug discovery. We can also see that structure-based compound design and optimization plays a critical role in facilitating the development of highly potent and selective chemical probes and inhibitors for these targets.
摘要：
N6-Methyladenosine (m6A) is the most prevalent internal RNA modification in eukaryotes. ALKBH5 belongs to the AlkB family of dioxygenases and has been shown to specifically demethylate m6A in single-stranded RNA. Here we report crystal structures of ALKBH5 in the presence of either its cofactors or the ALKBH5 inhibitor citrate. Catalytic assays demonstrate that the ALKBH5 catalytic domain can demethylate both single-stranded RNA and single-stranded DNA. We identify the TCA cycle intermediate citrate as a modest inhibitor of ALKHB5 (IC50, ∼488 μm). The structural analysis reveals that a loop region of ALKBH5 is immobilized by a disulfide bond that apparently excludes the binding of dsDNA to ALKBH5. We identify the m6A binding pocket of ALKBH5 and the key residues involved in m6A recognition using mutagenesis and ITC binding experiments.
作者：
Hanh T. Pham;Hajime Iwao;Jozsef Szelei;Yi Li;Kaiyu Liu;...
期刊：
Genome Announcements,2013年1(4) ISSN：2169-8287
通讯作者：
Tijssen, P.
作者机构：
[Hanh T. Pham; Jozsef Szelei; Max Bergoin; Peter Tijssen] INRS, Institut Armand-Frappier, Laval, QC, Canada;[Yi Li] Bioengineering Department, Wuhan Bioengineering Institute, Yangluo, Wuhan, Hubei, People's Republic of China;[Kaiyu Liu] College of Life Sciences, Central China Normal University, Wuhan, Hubei, People's Republic of China;[Hajime Iwao] Marinpia Nihonkai 5932-445, Nishifunami, Niigata, Japan
摘要：
The first densovirus from a cricket, Acheta domesticus densovirus (AdDNV) (Parvoviridae), was isolated in Europe in 1977 and has been studied previously. We compared seven additional AdDNV genomes isolated from 4 other European outbreaks, 2 major North American outbreaks, and a Japanese outbreak. Phylogenetic analysis suggested that the 2009 Japanese and North American outbreaks were not related.
作者机构：
[Li, Yongshu; Cai, Yingyue; Liu, Kaiyu; Yang, Yongbo; Sun, Bin; Li, Yi] Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Hubei, Peoples R China.;[Li, Jingjing] Hubei Normal Univ, Coll Life Sci, Huangshi 435002, Hubei, Peoples R China.;[Li, Yi] Wuhan Bioengn Inst, Bioengn Dept, Wuhan 430415, Hubei, Peoples R China.
通讯机构：
[Li, Yi] C;Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Hubei, Peoples R China.
关键词：
HBoV1;NP1;Apoptosis;Cell cycle arrest
摘要：
Human bocavirus type 1 (HBoV1) is a newly identified pathogen associated with human respiratory tract illnesses. Previous studies demonstrated that proteins of HBoV1 failed to cause cell death, which is considered as a possible common feature of bocaviruses. However, our work showed that the NP1 of HBoV1 induced apoptotic cell death in Hela cells in the absence of viral genome replication and expression of other viral proteins. Mitochondria apoptotic pathway was involved in the NP1-induced apoptosis that was confirmed by apoptotic characteristics including morphological changes, DNA fragmentation and caspase activation. We also demonstrated that the cell cycle of NP1-transfected Hela cells was transiently arrested at G2/M phase followed by rapid appearance of apoptosis and that the N terminal domain of NP1 was critical to its nuclear localization and function in apoptosis induction in Hela cells. These findings might provide alternative information for further study of mechanism of HBoV1 pathogenesis. (C) 2013 Elsevier Inc. All rights reserved.
摘要：
Nostoc flagelliforme is a terrestrial, highly drought-tolerant cyanobacterium. However, the molecular mechanism of its drought adaptation still remains little known. In this paper, we attempted to isolate those osmotic stress-regulated cDNA fragments by traditional differential display reverse transcriptase–polymerase chain reaction (DDRT-PCR). The PCR primers were chosen and evaluated from the reported HIP1D sequence-based primers and Ea/Es primers. The physiologically recovered samples were treated with 0.7 M sorbitol for 3 h. A total of 21 cDNA fragments were obtained by DDRT-PCR, and among them, 16 are up-regulated by osmotic stress. BlastX analyses showed that these up-regulated cDNA fragments are most related to ATPases, methyltransferases, transporters, glutathione synthase, signal transduction-associated components, and other unknown proteins. They are potentially important genes for N. flagelliforme to cope with drought stress since they are distinctly up-regulated by osmotic stress. In addition, five cDNA fragments are down-regulated by osmotic stress, such as the cDNA fragment of PSII protein. They may represent those genes involved in normal physiological processes and thus were inhibited by the osmotic stress. Taken together, the interpretation of the functional clues of these osmotic stress-responsive cDNA fragments has provided us an insight into the molecular mechanism of N. flagelliforme coping with the early phase of drought stress.
摘要：
Cholesterol is a membrane component and the precursor of ecdysteroids in insects, but insects cannot synthesize cholesterol de novo. Therefore, cholesterol uptake and transportation during the feeding larval stages are critical processes in insects. The sterol carrier protein-2 domain (SCP-2) in sterol carrier proteins-x (SCP-x) has been speculated to be involved in intracellular cholesterol transfer and metabolism in vertebrates. However, a direct association between SCP-x gene expression, cholesterol absorption and development in lepidopteran insects is poorly understood. We identified the Helicoverpa armigera sterol carrier protein-x/2 (HaSCP-x/2) gene from the larval midgut cDNAs. The HaSCP-x/2 gene is well conserved during evolution and relatively divergent in heterogenetic species. Transcripts of HaSCP-x/2 were detected by qRT-PCR at the highest level in the midgut of H. armigera during the larval stages. Expression knockdown of HaSCP-x/2 transcripts via dsRNA interference resulted in delayed larval development and decreased adult fecundity. Sterol carrier protein-2 inhibitors were lethal to young larvae and decreased fertility in adults emerged from treated elder larvae in H. armigera. The results taken together suggest that HaSCPx/2 gene is important for normal development and fertility in H. armigera. (C) 2012 Elsevier Ltd. All rights reserved.
