ITMSQ: A software tool for N‐ and C‐terminal fragment ion pairs based isobaric tandem mass spectrometry quantification

Tandem MS (MS2) quantification using the series of N‐ and C‐terminal fragment ion pairs generated from isobaric‐labelled peptides was recently considered an accurate strategy in quantitative proteomics. However, the presence of multiplexed terminal fragment ion in MS2 spectra may reduce the efficiency of peptide identification, resulting in lower identification scores or even incorrect assignments. To address this issue, we developed a quantitative software tool, denoted isobaric tandem MS quantification (ITMSQ), to improve N‐ and C‐terminal fragment ion pairs based isobaric MS2 quantification. A spectrum splitting module was designed to separate the MS2 spectra from different samples, increasing the accuracy of both identification and quantification. ITMSQ offers a convenient interface through which parameters can be changed along with the labelling method, and the result files and all of the intermediate files can be exported. We performed an analysis of in vivo terminal amino acid labelling labelled HeLa samples and found that the numbers of quantified proteins and peptides increased by 13.64 and 27.52% after spectrum splitting, respectively. In conclusion, ITMSQ provides an accurate and reliable quantitative solutionfor N‐ and C‐terminal fragment ion pairs based isobaric MS2 quantitative methods.     

湛江棕囊藻对南美白对虾虾苗和多种鱼苗的毒性研究

测定了湛江棕囊藻赤潮海水和棕囊藻(Phaeocystis globosa)对南美白对虾(Penaeus vannamei Boone)虾苗、青石斑鱼(Epinephelus awoara)、鲻鱼(Mugil cephalus)和尖吻鲈鱼(Latescal carifer)鱼苗的毒性。结果表明,棕囊藻对虾苗有一定的毒性,24 h LC50为1.0×109 cells L-1,去除囊泡液后的棕囊藻碎片对虾苗毒性较弱,细胞密度为1.0×109 cells L-1时,24 h虾苗的死亡率仅为10%,赤潮海水对虾苗无毒性;棕囊藻囊泡液对青石斑鱼有一定毒性,24 h LC50为囊泡液占海水总体积的10.9%,赤潮海水对青石斑鱼苗无毒性;棕囊藻对尖吻鲈鱼和鲻鱼鱼苗无毒性。     

pFGC5941的改造及拟南芥NAC1和SIP1双基因反义表达载体的构建和遗传转化

拟南芥中的SIP1基因编码的蛋白与拟南芥盐胁迫应答中的关键蛋白SOS2存在互作关系,而NAC1为拟南芥中介导生长素信号促进其侧根发生的蛋白。本研究中我们将SIP1基因和NAC1正义基因以及SIP1基因和NAC1反义基因分别整合到一个经改造的具有2个35S启动子的可用于双基因表达的载体pFGC5941S中,构建了两个双基因表达载体pFGC5941S SIP1 NAC1 sense和pFGC5941S SIP1 NAC1 anti。并将这两个载体通过农杆菌介导的方法转化到野生型拟南芥中,共获得15株转基因植株。对这些转基因植株进行盐胁迫实验发现,在含75mmol·L-1 NaCl的MS培养基上,相比于野生型,pFGC5941S SIP1 NAC1 sense转基因植株主根增长,侧根数量明显增多,而pFGC5941S SIP1 NAC1 anti转基因植株长势与野生型苗相似。由此我们推测可能只有当SIP1和NAC1同时过表达时,才会促进盐胁迫下拟南芥侧根的发育。     

Diallyl disulfide from garlic oil inhibits Pseudomonas aeruginosa virulence factors by inactivating key quorum sensing genes

Applied Microbiology and Biotechnology - Garlic oil can disrupt the quorum sensing (QS) pathways of the opportunistic pathogen Pseudomonas aeruginosa; however, the underlying mechanisms for this...     

Functional genomic analysis of Arabidopsis thaliana glycoside hydrolase family 35

Catalysing the hydrolysis of terminal beta-galactosyl residues from carbohydrates, galactolipids, and glycoproteins, glycoside hydrolase family 35 (beta-galactosidases; BGALs) are widely distributed in plants and believed to play many key roles, including modification of cell wall components. Completion of the Arabidopsis thaliana genome sequencing project has, for the first time, allowed an examination of the total number, gene structure, and evolutionary patterns of all Family 35 members in a representative (model) angiosperm. Reiterative database searches established a multigene family of 17 members (designated BGAL1-BGAL17). Using these genes as query sequences, BLAST and Hidden Markov Model searches identified BGAL genes among 22 other eukaryotes, whose genomic sequences are known. The Arabidopsis (n=17) and rice (n=15) BGAL families were much larger than those of Chlamydomonas, fungi, and animals (n=0-4), and a lineage-specific expansion of BGAL genes apparently occurred after divergence of the Arabidopsis and rice lineages. All plant BGAL genes, with the exception of Arabidopsis BGAL17 and rice Os 9633.m04334, form a monophyletic group. Arabidopsis BGAL expression levels are much higher in mature leaves, roots, flowers, and siliques but are lower in young seedlings. BGAL8, BGAL11, BGAL13, BGAL14, and BGAL16 are expressed only in flowers. Catalytically active BGAL4 was produced in the E. coli and baculoviral expression systems, purified to electrophoretic homogeneity, and partially characterized. The purified enzyme hydrolyzed p- and o-nitrophenyl-beta-d-galactosides. It also cleaved beta-(1,3)-, beta-(1,4)-, and beta-(1,6)-linked galactobiosides and galactotriosides, showing a marked preference for beta-(1,3)- and beta-(1,4)-linkages.     

Soluble expression, purification and functional identification of a disulfide-rich conotoxin derived from Conus litteratus

Conotoxins are a diverse array of small peptides mostly with multiple disulfide bridges. These peptides become an increasing significant source of neuro-pharmacological probes and drugs as a result of the high selectivity for ion channels and receptors. Usually, the analogue of natural conotoxins is produced by means of chemical synthesis. Here, we present a simple and fast strategy of producing disulfide-rich conotoxins via recombinant expression. By fused with thioredoxin and His tag, a novel O-superfamily conotoxin lt7a was successfully expressed in Escherichia coli and purified, resulting in a high yield of recombinant lt7a about 6 mg/l. The purity of target protein is up to 95% as identified by HPLC results. Whole cell patch-clamp recording revealed that the new conotoxin blocked voltage-sensitive sodium channels in rat dorsal root ganglion neurons, indicating it might be a novel microO-conotoxin.     

白刺属植物的分类学及系统学研究

在回顾白刺属(NitrariaL)研究历史的基础上,对全球所产白刺属的12种植物作了详细的考证和系统整理。根据果皮结构及演化趋势,花粉形态及分布区等方面的研究资料,探讨了属内种间的系统发育,提出了属下的分类系统,在此系统下编制出分组及分种检索表。根据其地理分布,绘制了白刺属植物的中国及世界分布图。