Homo- and hetero-dimerization of LPA/S1P receptors, OGR1 and GPR4

G protein coupled receptors (GPCRs) form homo- and hetero-dimers or -oligomers, which are functionally important. Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are bioactive lysophopholipids involved in diverse biological processes. We have examined homo- and hetero-dimerization among three major LPA receptors (LPA(1-3)), three major S1P receptors (S1P(1-3)), as well as OGR1 and GPR4. Using LacZ complementation assays, we have shown that LPA receptors form homo- and hetero-dimers within the LPA receptor subgroup and hetero-dimers with other receptors (S1P(1-3) and GPR4). In addition, we have found that although GPR4 and OGR1 share more than 50% homology, GPR4 forms strong homo- and hetero-dimers with LPA and S1P receptors, but OGR1 forms very weak homo-dimer and relatively weak hetero-dimers with other receptors. Using chimeric receptors between GPR4 and OGR1, we have shown that different domains of GPR4 receptor are involved in its dimerization with different GPCRs and more than one domain may be involved in some of the complex formation. Our results suggest that when studying a signal transduction induced by a stimulus, not only is the expression and activation of its own receptor(s), but also the status of the interacting receptors should be taken into consideration.     

喀斯特高原山地石漠化区叶蝉群落结构及其多样性动态变化

为了探讨喀斯特石漠化治理区叶蝉群落对生态功能变动的动态响应,在中国贵州毕节撒拉溪朝营小流域按不同等级石漠化程度设置样地,并设置响应对照组,在2013-2014年5-10月每月对样地进行野外调查,系统采集叶蝉标本和在室内开展生物多样性研究,以期分析高原山地不同等级石漠化程度下叶蝉群落的时空格局,特别是对石漠化治理效果的生态学响应。结果表明,共采得叶蝉3049头,隶属11亚科53属,其中优势类群为小叶蝉亚科、角顶叶蝉亚科、大叶蝉亚科,分别占总数的44.70%、21.78%、14.66%。与对照组相比,治理区内样地叶蝉的属数、个体数都有增加,并表现出明显的季节变动,在7月、8月物种丰富度指数最高;随着石漠化治理的深入,叶蝉种数、个体数呈增加趋势。总体上,石漠化等级与叶蝉群落结构特征指数呈现显著的负相关,石漠化等级越低,叶蝉的Shannon-Wiener多样性指数和Margale丰富度指数越大。各等级石漠化样地的Pieluo均匀度指数与优势度指数呈现反向耦合。     

人Ⅳ型胶原的提纯及其抗血清制备

采用胃蛋白酶限制性消化,NaCl分级盐析,还原和烷基化反应,纤维素离子交换层析从人胎盘组织分离纯化Ⅳ型胶原.经SDS-PAGE电泳鉴定符合Ⅳ型胶原α肽链电泳带.用纯化的Ⅳ型胶原免疫兔制备出高效价的特异抗血清.     

Regulation of progesterone during follicular development by FSH and LH in sheep

Progesterone (P4) can participate in the development of female mammalian antral follicles through nuclear receptor (PGR). In this experiment, the differences of P4 synthesis and PGR expression in different developmental stages of sheep antral follicles (large > 5mm, medium 2-5mm, small < 2mm) were detected by enzyme-linked immunosorbent assay, immunohistochemistry, qRT-PCR and Western blotting. Secondly, sheep follicular granulosa cells were cultured in vitro. The effects of different concentrations of FSH and LH on P4 synthesis and PGR expression were studied. The results showed that acute steroid regulatory protein (StAR), cholesterol side chain lyase (P450scc) and 3β Hydroxysteroid dehydrogenase (3β-HSD) and PGR were expressed in antral follicles, and with the development of antral follicles in sheep, StAR, P450scc and the expression of 3β-HSD and PGR increased significantly. In vitro experiments showed that FSH and LH alone or together treatment could regulate P4 secretion and PGR expression in sheep follicular granulosa cells to varying degrees, hint P4 and PGR by FSH and LH, and LH was the main factor. Our results supplement the effects of FSH and LH on the regulation of P4 synthesis during follicular development, which provides new data for further study of steroid synthesis and function in follicular development.     

Tiller number is altered in the ascorbic acid-deficient rice suppressed for l-galactono-1,4-lactone dehydrogenase

The tiller of rice (Oryza sativa L.), which determines the panicle number per plant, is an important agronomic trait for grain production. Ascorbic acid (Asc) is a major plant antioxidant that serves many functions in plants. l-Galactono-1,4-lactone dehydrogenase (GLDH, EC 1.3.2.3) is an enzyme that catalyzes the last step of Asc biosynthesis in plants. Here we show that the GLDH-suppressed transgenic rices, GI-1 and GI-2, which have constitutively low (between 30% and 50%) leaf Asc content compared with the wild-type plants, exhibit a significantly reduced tiller number. Moreover, lower growth rate and plant height were observed in the Asc-deficient plants relative to the trait values of the wild-type plants at different tillering stages. Further examination showed that the deficiency of Asc resulted in a higher lipid peroxidation, a loss of chlorophyll, a loss of carotenoids, and a lower rate of CO₂ assimilation. In addition, the level of abscisic acid was higher in GI-1 plants, while the level of jasmonic acid was higher in GI-1 and GI-2 plants at different tillering stages. The results we presented here indicated that Asc deficiency was likely responsible for the promotion of premature senescence, which was accompanied by a marked decrease in photosynthesis. These observations support the conclusion that the deficiency of Asc alters the tiller number in the GLDH-suppressed transgenics through promoting premature senescence and changing phytohormones related to senescence.     

Identification of a Novel Universal Potential Epitope on the Cytoplasmic Tail of H7N9 Virus Hemagglutinin

<正>Dear Editor,H7 N9 is a recently identified subtype of influenza A virus that caused a major outbreak in humans in China in 2013.According to the latest data provided by the Chinese Center for Disease Control and Prevention(http://www.moh.gov.cn/zwgk/yqbb3/ejlist.shtml, updated on October 31, 2018),the mortality rate of H7 N9 infections in China amounts to     

Genome Sequence of Staphylococcus capitis QN1, Which Causes Infective Endocarditis

Staphylococcus capitis is a subtype of coagulase-negative staphylococci (CoNS) which could emerge as a significant pathogen causing infective endocarditis, prosthetic valve endocarditis, and late-onset sepsis. We isolated S. capitis strain QN1 from the skin swab sample of a female. Here we prepared a genome sequence for this strain consisting of 30 contigs totaling 2,430,101 bases and a GC content of 32.76%.     

Structural basis for dual-inhibition mechanism of a non-classical Kazal-type serine protease inhibitor from horseshoe crab in complex with subtilisin

Serine proteases play a crucial role in host-pathogen interactions. In the innate immune system of invertebrates, multi-domain protease inhibitors are important for the regulation of host-pathogen interactions and antimicrobial activities. Serine protease inhibitors, 9.3-kDa CrSPI isoforms 1 and 2, have been identified from the hepatopancreas of the horseshoe crab, Carcinoscorpius rotundicauda. The CrSPIs were biochemically active, especially CrSPI-1, which potently inhibited subtilisin (Ki = 1.43 nM). CrSPI has been grouped with the non-classical Kazal-type inhibitors due to its unusual cysteine distribution. Here we report the crystal structure of CrSPI-1 in complex with subtilisin at 2.6 Å resolution and the results of biophysical interaction studies. The CrSPI-1 molecule has two domains arranged in an extended conformation. These two domains act as heads that independently interact with two separate subtilisin molecules, resulting in the inhibition of subtilisin activity at a ratio of 1:2 (inhibitor to protease). Each subtilisin molecule interacts with the reactive site loop from each domain of CrSPI-1 through a standard canonical binding mode and forms a single ternary complex. In addition, we propose the substrate preferences of each domain of CrSPI-1. Domain 2 is specific towards the bacterial protease subtilisin, while domain 1 is likely to interact with the host protease, Furin. Elucidation of the structure of the CrSPI-1: subtilisin (1∶2) ternary complex increases our understanding of host-pathogen interactions in the innate immune system at the molecular level and provides new strategies for immunomodulation.     

A subset of chemosensory genes differs between two populations of a specialized leaf beetle after host plant shift

Due to its fundamental role in shaping host selection behavior, we have analyzed the chemosensory repertoire of Chrysomela lapponica. This specialized leaf beetle evolved distinct populations which shifted from the ancestral host plant, willow (Salix sp., Salicaceae), to birch (Betula rotundifolia, Betulaceae). We identified 114 chemosensory candidate genes in adult C. lapponica: 41 olfactory receptors (ORs), eight gustatory receptors, 17 ionotropic receptors, four sensory neuron membrane proteins, 32 odorant binding proteins (OBPs), and 12 chemosensory proteins (CSP) by RNA‐seq. Differential expression analyses in the antennae revealed significant upregulation of one minus‐C OBP (ClapOBP27) and one CSP (ClapCSP12) in the willow feeders. In contrast, one OR (ClapOR17), four minus‐C OBPs (ClapOBP02, 07, 13, 20), and one plus‐C OBP (ClapOBP32) were significantly upregulated in birch feeders. The differential expression pattern in the legs was more complex. To narrow down putative ligands acting as cues for host discrimination, the relative abundance and diversity of volatiles of the two host plant species were analyzed. In addition to salicylaldehyde (willow‐specific), both plant species differed mainly in their emission rate of terpenoids such as (E,E)‐α‐farnesene (high in willow) or 4,8‐dimethylnona‐1,3,7‐triene (high in birch). Qualitatively, the volatiles were similar between willow and birch leaves constituting an “olfactory bridge” for the beetles. Subsequent structural modeling of the three most differentially expressed OBPs and docking studies using 22 host volatiles indicated that ligands bind with varying affinity. We suggest that the evolution of particularly minus‐C OBPs and ORs in C. lapponica facilitated its host plant shift via chemosensation of the phytochemicals from birch as novel host plant.     

重组酶法定量分析吡咯喹啉醌

用ＤＥＡＥ－ｓｅｐｈａｃｅｌ和ＣＭ－ｃｅｌｕｌｏｓｅ柱层析的方法从Ｃｏｍａｍｏｎａｓｔｅｓｔｏｓｔｅｒｏｎｉ菌体中纯化得到一定纯度的脱辅基的乙醇脱氢酶。在含３ｍＭＣａＣｌ２的Ｔｒｉｓ／ＨＣｌ缓冲液（２０ｍＭ,ｐＨ７．０）中,该酶能与ＰＱＱ重组成有活性的全酶,测出的全酶活性大小与外加ＰＱＱ的量成正比,从而定量分析ＰＱＱ。该法专一、灵敏、可靠。