Whole-Genome Sequence Analysis and Genome-Wide Virulence Gene Identification of Riemerella anatipestifer Strain Yb2

Riemerella anatipestifer is a well-described pathogen of waterfowl and other avian species that can cause septicemic and exudative diseases. In this study, we sequenced the complete genome of R. anatipestifer strain Yb2 and analyzed it against the published genomic sequences of R. anatipestifer strains DSM15868, RA-GD, RA-CH-1, and RA-CH-2. The Yb2 genome contains one circular chromosome of 2,184,066 bp with a 35.73% GC content and no plasmid. The genome has 2,021 open reading frames that occupy 90.88% of the genome. A comparative genomic analysis revealed that genome organization is highly conserved among R. anatipestifer strains, except for four inversions of a sequence segment in Yb2. A phylogenetic analysis found that the closest neighbor of Yb2 is RA-GD. Furthermore, we constructed a library of 3,175 mutants by random transposon mutagenesis, and 100 mutants exhibiting more than 100-fold-attenuated virulence were obtained by animal screening experiments. Southern blot analysis and genetic characterization of the mutants led to the identification of 49 virulence genes. Of these, 25 encode cytoplasmic proteins, 6 encode cytoplasmic membrane proteins, 4 encode outer membrane proteins, and the subcellular localization of the remaining 14 gene products is unknown. The functional classification of orthologous-group clusters revealed that 16 genes are associated with metabolism, 6 are associated with cellular processing and signaling, and 4 are associated with information storage and processing. The functions of the other 23 genes are poorly characterized or unknown. This genome-wide study identified genes important to the virulence of R. anatipestifer.     

All members in the sphingomyelin synthase gene family have ceramide phosphoethanolamine synthase activity

Sphingomyelin synthase-related protein (SMSr) synthesizes the sphingomyelin analog ceramide phosphoethanolamine (CPE) in cells. Previous cell studies indicated that SMSr is involved in ceramide homeostasis and is crucial for cell function. To further examine SMSr function in vivo, we generated Smsr KO mice that were fertile and had no obvious phenotypic alterations. Quantitative MS analyses of plasma, liver, and macrophages from the KO mice revealed only marginal changes in CPE and ceramide as well as other sphingolipid levels. Because SMS2 also has CPE synthase activity, we prepared Smsr/Sms2 double KO mice. We found that CPE levels were not significantly changed in macrophages, suggesting that CPE levels are not exclusively dependent on SMSr and SMS2 activities. We then measured CPE levels in Sms1 KO mice and found that Sms1 deficiency also reduced plasma CPE levels. Importantly, we found that expression of Sms1 or Sms2 in SF9 insect cells significantly increased not only SM but also CPE formation, indicating that SMS1 also has CPE synthase activity. Moreover, we measured CPE synthase K_m and V_max for SMS1, SMS2, and SMSr using different NBD ceramides. Our study reveals that all mouse SMS family members (SMSr, SMS1, and SMS2) have CPE synthase activity. However, neither CPE nor SMSr appears to be a critical regulator of ceramide levels in vivo.     

New species of Nepalomyia henanensis species group from China(Diptera: Dolichopodidae: Peloropeodinae)

Three new species of Nepalomyia henanensis species group are described from China, N. damingshanus sp. nov., N. dongae sp. nov., and N. shennongjiaensis sp. nov. A key to known species of this species group is presented.     

Alleviation of the detrimental effect of water deficit on wheat (Triticum aestivum L.) growth by an indole acetic acid-producing endophytic fungus

Plant and Soil - Endophytic fungi colonization is an eco-friendly strategy to respond to environmental stresses and confer tolerance to the host plant. Here, the responses of wheat plant inoculated...     

江苏菜豆同工凝集素的分离纯化及性质研究

江苏菜豆经酸水(PH2.0)抽提,硫酸铵分级沉淀,分离植物血球凝集素(PHA-P),分子量为128000的糖蛋白,活性回收率在80％以上,PHA-P经SP-sephadexc-50离子交换层析,分成L_4,L_3E_1,L_2E_2,L_1E_3,和E_4同工凝集素。 L_4和E_4等电点为5.4和6.5。亚基分子量分别是31000和33000,并有类似的氨基酸组成。PAGE分析为单一蛋白带。红细胞凝集活性随电泳迁移速度的加快而增强,促淋性细胞分裂活性则减弱。E_4血凝活性受CalNAc,EDTA抑制和Zn~(++)的促进。     

Structure of a Pancreatic ATP-Sensitive Potassium Channel

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A homogalacturonan from the radix of Platycodon grandiflorum and the anti-angiogenesis activity of poly-/oligogalacturonic acids derived therefrom

A polysaccharide, PGA4-3b, with an average molecular weight of 8.9 kDa estimated by high-performance gel-permeation chromatography (HPGPC), was isolated from radix of Platycodon grandiflorum (Jacq.) A. DC. Using monosaccharide analysis, methylation analysis and NMR spectroscopy, PGA4-3b was elucidated to be a linear poly-(1→4)-α-d-galactopyranosyluronic acid that contains no methyl ester groups. Partial acid hydrolysis of PGA4-3b yielded a series of poly- or oligogalacturonic acids with different degrees of polymerization (DP), that is, 4-3bde, 4-3bde-O-1, 4-3bde-O-2, 4-3bde-O-3, and 4-3bde-O-4. Cell tube formation inhibition tests with human microvascular endothelial cells (HMEC) for antiangiogenesis analysis showed that 4-3bde-O-1 and 4-3bde-O-2, the fractions with higher molecular weights, could inhibit tube formation, while the native PGA4-3b and low molecular weight fraction 4-3bde-O-3 and 4-3bde-O4 are ineffective. Moreover, 4-3bde-O-2 with DP 5-10 impaired cell tube formation in a dose-dependent way, suggesting its potential to be developed as an anti-angiogenesis drug. This is the first time oligogalacturonic acids are reported to show an anti-angiogenesis effect.     

A proteomic analysis of the chromoplasts isolated from sweet orange fruits [Citrus sinensis (L.) Osbeck

Here, a comprehensive proteomic analysis of the chromoplasts purified from sweet orange using Nycodenz density gradient centrifugation is reported. A GeLC-MS/MS shotgun approach was used to identify the proteins of pooled chromoplast samples. A total of 493 proteins were identified from purified chromoplasts, of which 418 are putative plastid proteins based on in silico sequence homology and functional analyses. Based on the predicted functions of these identified plastid proteins, a large proportion (～60%) of the chromoplast proteome of sweet orange is constituted by proteins involved in carbohydrate metabolism, amino acid/protein synthesis, and secondary metabolism. Of note, HDS (hydroxymethylbutenyl 4-diphosphate synthase), PAP (plastid-lipid-associated protein), and psHSPs (plastid small heat shock proteins) involved in the synthesis or storage of carotenoid and stress response are among the most abundant proteins identified. A comparison of chromoplast proteomes between sweet orange and tomato suggested a high level of conservation in a broad range of metabolic pathways. However, the citrus chromoplast was characterized by more extensive carotenoid synthesis, extensive amino acid synthesis without nitrogen assimilation, and evidence for lipid metabolism concerning jasmonic acid synthesis. In conclusion, this study provides an insight into the major metabolic pathways as well as some unique characteristics of the sweet orange chromoplasts at the whole proteome level.     

中国距水虻属四新种(双翅目,水虻科)(英文)

记述我国距水虻属Allognosta 4新种,基黑距水虻A.basinigra sp.nov.,彩旗距水虻A.caiqiana sp.nov.,大龙潭距水虻A.dalongtana sp.nov.,梁氏距水虻A.liangi sp.nov.。模式标本保存在中国农业大学昆虫博物馆。