北京市蛇类新纪录——中介蝮

2011年6月,在北京市门头沟区小龙门林场进行教学实习时,采集到2号蛇类标本,经鉴定为中介蝮(Gloydius intermedius),为北京市蛇类新纪录。     

广西蛇类新纪录——角原矛头蝮

正2015年4月14日于广西金秀大瑶山国家级自然保护区发现1号亚成体活体蛇类标本,经查阅文献和鉴定确认为角原矛头蝮Protobothrops cornutus,为广西蛇类的新纪录。该地点是我国发现角原矛头蝮的第6个分布点(梁启燊,2003;赵尔宓,2006;龚世平等,2010;王聿凡等,2015)。本次采集的角原矛头蝮标本全长431.0 mm,头长18.3     

河南省驻马店发现大别山原矛头蝮

<正>2016年9月17日,河南省驻马店市西平县村民王孝在自家果园中(33°11′32.45″N,113°37′19.42″E,海拔218 m)采集到1号蛇类标本,置于75%酒精保存后,送至沈阳师范大学两栖爬行动物研究所,经鉴定为蝰科(Viperidae)蝮亚科(Crotalinae)原矛头蝮属(Protobothrops)大别山原矛头蝮(P.dabieshanensis),为河南省蛇类新纪录种,     

北京及邻近地区蛇类存疑种分布及讨论

本研究基于前人对北京及邻近地区蛇类的基础调查文献进行总结,并于2010—2016年,多次对北京及邻近地区进行蛇类资源调查。本研究根据调查结果和现有文献对北京蛇类多样性资源予以初步总结,并对部分存疑物种进行讨论。其中,黑头剑蛇Sibynophis chinensis曾被认为是人为引入的物种,但本研究证实其应为原生种;北京地区所纪录的"中介蝮"实际应为2个不同种,分别为华北蝮G.stejnegeri和西伯利亚蝮指名亚种G.halys halys;乌苏里蝮G.ussuriensis系误记,应为短尾蝮G.brevicaudus。     

几种腹蛇12S rRNA和Cyt b 基因片段序列的初步研究

首次对我国几种腹属蛇类的12S rRNA和Cyt b 基因的部分序列进行了测定。12S rRNA基因片段序列结果揭示：中介蝮有较大的种下分化。本文为蝮属蛇类的分子系统学研究提供了一些资料。     

几种腹蛇12S rRNA和Cyt b基因片段序列的初步研究

首次对我国几种腹属蛇类的１２Ｓ ｒＲＮＡ和Ｃｙｔ ｂ基因的部分序列进行了测定。１２Ｓ ｒＲＮＡ基因片段序列结果揭示：中介蝮有较大的种下分化。本文为蝮属蛇类的分子系统学研究提供了一些资料。     

中国蝮属蛇类的RAPD分析

用ＲＡＰＤ技术研究了我国５种蝮属蛇类（中介蝮，蛇岛蝮，短尾蝮，高原蝮，乌苏里蝮）的系统发生关系，研究中使用了３３个蝮蛇标本和２个草原蝰标本，用１１个引物对样品分别作ＲＡＰＤ扩增，获得７２个扩增片段。     

辽宁省青龙河自然保护区发现中介蝮

2013年8月8日,在辽宁省凌源市青龙河自然保护区红石砬子山主峰(40°47'N,118°55'E,海拔1 253 m)采集到2号亚洲蝮属(Gloydius)蛇类标本,经鉴定为中介蝮(G.intermedius),系该种在辽宁省境内首次发现。本文对其形态特征进行了描述,并与国内其他地区的标本进行了比较,讨论了其分布格局和生物地理学特点。     

浙江省发现角原矛头蝮

<正>2014年7月24日,于浙江省台州市仙居县(28°37′N,120°36′E,海拔339 m)发现1号雄性活体蛇类标本,经查阅文献和鉴定,确认为角原矛头蝮(Protobothrops cornutus),系华东地区及浙江省蛇类属、种的地理新分布,也是我国发现角原矛头蝮仅有的第5个分布点。本次采集的角原矛头蝮标本全长615.0 mm,头长26.0 mm,体长484.0 mm,尾长105.0 mm。头呈三角形,头颈部区分明显,上颌1对管牙,鼻眼间有颊窝,颊窝由3片大鳞围成,其中1枚为第2上唇鳞。上唇鳞10枚,鼻鳞与第1上唇鳞分离。下唇鳞14枚。舌前段2/3为黑色,后     

中国特有蛇类资源及保护建议

概述了中国54种特有蛇类状况,对香港盲蛇Typhlops lazelli、温泉蛇Thermophis baileyi、莽山烙铁头蛇Zhaoermia mangshanensis和蛇岛蝮Gloydius shedaoensis 4种极危种类进行了初步分析.讨论了中国特有蛇类的受胁现状及因素,提出保护策略和措施,建议建立中国特有珍稀蛇类繁育基地.     

Comparative Microhabitat Use of Ecologically Similar Benthic Fishes

Although benthic insectivorous fishes such as darters and sculpins represent a significant component of riffle communities, few studies have compared the habitat use of these non-related but ecologically similar fishes. The objectives of this study were to examine the habitat use of Etheostoma olmstedi (tessellated darter) compared to Cottus bairdi (mottled sculpin) in Nescopeck Creek and Cottus cognatus (slimy sculpin) in Jack's Creek, Pennsylvania through underwater observation. Etheostoma olmstedi occupied habitats with significantly deeper waters than those available, whereas adult and young of the year Cottus occupied habitats with significantly faster water velocities than those available. Canonical discriminant analysis revealed microhabitat partitioning between E. olmstedi and each Cottus species. Cottus bairdi and C. cognatus occupied significantly shallower habitats with faster water velocities than E. olmstedi. Sculpin species were observed most frequently under substrate whereas E. olmstedi occurred most frequently on the top surface of the substrate. Hurlbert's standardized niche breadth values indicated that C. bairdi and C. cognatus were habitat specialists with regard to water velocity measures, but exhibited generalistic patterns of depth and substrate size use. Etheostoma olmstedi was a habitat specialist with respect to depth, but exhibited generalistic patterns of resource use for substrate size. Differential habitat use by these benthic fishes is consistent with the hypothesis that resource partitioning facilitates species coexistence among stream fishes.     

具有细菌群体感应抑制活性海洋来源真菌的筛选鉴定

许多致病菌的致病机制依赖于群体感应系统的调控,经实验证明群体感应系统突变或缺失的菌株致病能力显著下降,筛选高效的群体感应抑制剂有望成为解决细菌感染以及细菌耐药性问题的一个有效途径。从海洋软体动物体内分离海洋真菌69株,发酵液粗提物经QSIS2 (Quorum Sensing Inhibitor Selector 2) 筛选模型和紫色杆菌CV026指示菌株筛选后得到编号QY013的粗提物具有群体感应抑制活性,进一步实验表明该粗提物能够显著降低铜绿假单胞菌群体感应调控的毒力因子绿脓菌素的产量,以及紫色杆菌群体感应调控的紫色菌素的产量,且在有效浓度范围内对细菌生长不产生影响。形态学特征和18S rDNA序列分析表明菌株QY013为Penicillium属。文中筛选到一株具有细菌群体感应抑制活性的海洋来源真菌,其发酵液粗提物中的有效活性成分可用于新型抗菌药物的研究。     

Population differentiation of temperate amphibians in unpredictable environments

Amphibians are a globally distributed and diverse lineage, but much of our current understanding of their population genetic structure comes from studies in mesic temperate habitats. We characterize the population genetic structure of two sympatric explosive breeding amphibians in the southwestern deserts of the United States: the Great Plains toad ( Anaxyrus cognatus ) and Couch's spadefoot toad ( Scaphiopus couchii ). For both species, we find limited genetic differentiation even between populations in adjacent valleys separated by dispersal barriers such as mountainous habitats. To understand how population genetic patterns in these two arid-adapted species compare to taxa in more mesic environments, we computed a standardized measure of population differentiation for A. cognatus , S. couchii , and for pond-breeding amphibians that inhabit mesic temperate environments. Our results indicate that the arid-adapted species have lower population genetic structure at fine and moderate scales than most other amphibian species we surveyed. We hypothesize that stochasticity in the availability of appropriate breeding sites as well as landscape homogeneity may result in increased population connectivity in desert-adapted frogs. Future work examining fine-scale population structure in amphibians from a diversity of habitats will test the generality of our findings. Intraspecific comparisons among localities with varied seasonality and habitats will be particularly useful for investigating the interaction between species-typical population dynamics and environmental characteristics as determinants of population connectivity in pond-breeding amphibians.     

Complete genome sequence of porcine reproductive and respiratory syndrome virus strain QY2010 reveals a novel subgroup emerging in China

QY2010 is a highly pathogenic North American-type porcine reproductive and respiratory syndrome virus (PRRSV). The complete genome sequence shows that QY2010 shares low sequence identity (60 to 88.7%) to all known PRRSV isolates. Phylogenetic analyses further reveal that QY2010 constitutes a novel subgroup within the North American genotype of PRRSV.     

The site of photoinhibition in leaves of Cucumis sativus L. at low temperatures is photosystem I,not photosystem II

Maximum quantum yields (QY) of photosynthetic electron flows through PSI and PSII were separately assessed in thylakoid membranes isolated from leaves of Cucumis sativus L. (cucumber) that had been chilled in various ways. The QY(PSI) in the thylakoids prepared from the leaves treated at 4° C in moderate light at 220 mol quanta·m^–2·s^–1 (400–700 nm) for 5 h, was about 20–30% of that in the thylakoids prepared from untreated leaves, while QY(PSII) decreased, at most, by 20% in response to the same treatment. The decrease in QY(PSI) was observed only when the leaves were chilled at temperatures below 10° C, while such a marked temperature dependency was not observed for the decrease in QY(PSII). In the chilling treatment at 4° C for 5 h, the quantum flux density that was required to induce 50% loss of QY (PSI) was ca. 50 umol quanta·m^–2·s^–1. When the chilling treatment at 4° C in the light was conducted in an atmosphere of N₂, photoinhibition of PSI was largely suppressed, while the damage to PSII was somewhat enhanced. The ferricyanide-oxidised minus ascorbate-reduced difference spectra and the light-induced absorbance changes at 700 nm obtained with the thylakoid suspension, indicated the loss of P700 to extents that corresponded to the decreases in QY(PSI). Accordingly, the decreases in QY(PSI) can largely be attributed to destruction of the PSI reaction centre itself. These results clearly show that, at least in cucumber, a typical chillingsensitive plant, PSI is much more susceptible to aerobic photoinhibition than PSII.Abbreviations DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea - P700 primary electron donor of PSI - PPFD photosynthetically active photon flux density - QY quantum yield We are grateful to invaluable comments by Prof. S. Katoh, K. Hikosaka and the members of our laboratory. We also thank A. Aoyama for technical assistance. This work was partly supported by the grants from the Ministry of Education, Science, and Culture, Japan, to I. Terashima (#03740342 and #04640621).     

Deposition of CdS,CdS/ZnSe and CdS/ZnSe/ZnS shells around CdSeTe alloyed core quantum dots: effects on optical properties

In this work, we synthesized water‐soluble L ‐cysteine‐capped alloyed CdSeTe core quantum dots (QDs) and investigated the structural and optical properties of deposition of each of CdS, CdS/ZnSe and CdS/ZnSe/ZnS shell layers. Photophysical results showed that the overcoating of a CdS shell around the alloyed CdSeTe core [quantum yield (QY) = 8.4%] resulted in effective confinement of the radiative exciton with an improved QY value of 93.5%. Subsequent deposition of a ZnSe shell around the CdSeTe/CdS surface decreased the QY value to 24.7%, but an increase in the QY value of up to 49.5% was observed when a ZnS shell was overcoated around the CdSeTe/CdS/ZnSe surface. QDs with shell layers showed improved stability relative to the core. Data obtained from time‐resolved fluorescence measurements provided useful insight into variations in the photophysical properties of the QDs upon the formation of each shell layer. Our study suggests that the formation of CdSeTe/CdS core/shell QDs meets the requirements of quality QDs in terms of high photoluminescence QY and stability, hence further deposition of additional shells are not necessary in improving the optical properties of the core/shell QDs. Copyright © 2015 John Wiley & Sons, Ltd.     

产双功能褐藻胶裂解酶菌株的筛选与初步研究

目的：双功能褐藻胶裂解酶既能降解聚β-D-甘露糖醛酸,又能降解聚α-L-古罗糖醛酸,可以用一种酶来制备不同结构的褐藻胶寡糖。本文的目的是筛选能产生双功能褐藻胶裂解酶的菌株,对其产酶曲线和降解产物作初步研究。方法：利用唯一碳源培养基筛选产生褐藻胶裂解酶的菌株,通过16SrDNA序列比对进行菌种鉴定,通过在凝胶上检测褐藻胶裂解酶活性来判断发酵上清液中褐藻胶裂解酶的数量及分子量,利用薄层层析确定降解褐藻胶的终产物组成。结果：从褐藻上筛选到一株海洋细菌QY107,鉴定为弧菌属细菌。发酵120h时褐藻胶裂解酶产量为12．32U／mL,其发酵液上清中只含有一种褐藻胶裂解酶,分子量在28kDa左右,并且对聚β—D-甘露糖醛酸和聚α-L-古罗糖醛酸都能降解,降解褐藻胶的终产物主要为三糖。结论：本文筛选到一株弧菌QY107,其发酵液上清中只有一种双功能褐藻胶裂解酶,可用于大量制备褐藻胶三糖。推测该酶具有特殊的催化腔结构,对其结构与功能相互关系的研究可能会发现新的底物结合与催化机制。酶解制备褐藻胶寡糖因其环保高效而越来越受到人们的重视,因此该菌株能促进海洋寡糖类生物制品的开发,在医药、食品、农业、生物燃料等领域具有广阔的应用前景。     

Metacercariae of Clinostomum attenuatum in Ambystoma tigrinum mavortium, Bufo cognatus and Spea multiplicata from west Texas

Tissues from barred tiger salamanders (Ambystoma tigrinum mavortium), Great Plains toads (Bufo cognatus) and New Mexico spadefoots (Spea multiplicata) collected from 16 playa wetlands in Texas during 1999 and 2000 were examined by light microscopy. Digenean cysts were primarily distributed subcutaneously throughout the specimens and occasionally coelomic invasion was noted. The parasites within the cysts were 1.5-2 mm in diameter, with a thin (c. 10 microm wide) eosinophilic-staining tegument, two suckers (oral and ventral), posteriorly located primordial genitalia and paired digestive caeca. These digeneans were identified as the metacercariae of Clinostomum attenuatum. This is the first record of Clinostomum attenuatum in these amphibian species.     

Discovery of the selective sphingomyelin synthase 2 inhibitors with the novel structure of oxazolopyridine

Sphingomyelin synthase (SMS) is a key enzyme in sphingomyelin biosynthetic pathway, whose activity is highly related to the atherosclerosis progression. SMS2 could serve as a promising therapeutic target for atherosclerosis. Based on the structure of lead compound D2, a series of oxazolopyridine derivatives were designed, synthesized, and their inhibitory activities against purified SMS1 and SMS2 enzymes were evaluated respectively. The representative molecules QY4 and QY16 possess micromolar inhibitory activities against SMS2 and excellent isoform preferences over SMS1, qualified to be selected as potential molecules in further discovery of specific SMS2 inhibitors.     

Bis-pyrene-labeled oligonucleotides: sequence specificity of excimer and monomer fluorescence changes upon hybridization with DNA

The design, synthesis, and properties of a new pyrene excimer-forming probe of DNA have been described. 2,2-(Aminomethyl)propanediol was converted by the reaction with 1-pyrenebutylic acid to bis-pyrene-modified propanediol as a fluorescent non-nucleosidic linker. The bis-pyrene-modified linker can be incorporated via phosphoramidite chemistry into the 5'-terminal or internal positions of oligonucleotides (ODNs). The terminally modified ODNs showed almost similar affinity for complementary DNA when compared with the corresponding unmodified ODNs. The duplexes containing the bis-pyrene in the main chain exhibited higher melting temperatures relative to the corresponding duplexes containing propanediol linker at the same position. The UV and CD spectral studies indicate that the stacking interactions between the pyrene and DNA bases occur in the internally modified duplex and do not in the terminally modified duplex. The bis-pyrene modified linker itself displays excimer (E at 480 nm) and monomer (M at 380 nm) emission in a quantum yield (QY) of 0.17 and the E/M intensity ratio of 15. Incorporation of this linker into the terminal or internal positions of ODNs reduced the QY (0.003-0.009) and the E/M ratio (0.3-0.8). While small changes in the QY and E/M ratio was obtained in binding of the internally labeled ODNs to DNA, up to 27-fold increase in the QY and 17-fold increase in the E/M ratio was observed upon hybridization of the terminally labeled ODNs with DNA. The excimer and monomer fluorescence changes were found to be sensitive to a mismatch base present in the target DNA. The bis-pyrene-modified ODNs thus provide a sequence-sepcific fluorescent probe of DNA.