甘肃临夏盆地晚中新世貘类化石(奇蹄目、貘科)一新种

描述在甘肃临夏盆地晚中新世地层中发现的貘属新种和政貘(Tapirus hezhengensis sp. nov.),它是貘属中已知最小的种之一。在基本特征上,临夏盆地的和政貘与现生貘已相当接近,前臼齿完全臼齿化,门齿、犬齿的数目和形态也与现生貘一致。东亚晚中新世缺少貘科化石的材料,和政貘的发现对中国第四纪貘类的来源提供了重要线索,显示中中新世起源于欧洲的真貘在晚中新世时期已扩散至东亚。貘类通常适应于潮湿的热带森林环境,但和政貘在华北三趾马动物群中的发现说明这类动物也能够生活于干旱的温带草原地区。     

内蒙古二连盆地沙拉木伦地区中始新世全脊貘(Teleolophus)(奇蹄目:貘超科)头后骨骼研究（英文）

戴氏貘科(Deperetellidae)是亚洲中始新世地层中常见且特有的貘类,目前包括了5个属。但已知的戴氏貘材料大部分都是破损的上、下颌骨,仅有Deperetella保存有部分头后骨骼。仅依据牙齿的特征,戴氏貘在貘超科中的系统发育位置有很大争议,比如沼貘科的Colodon,脊齿貘(lophialetids)或红山貘(rhodopagids)都被认为可能和戴氏貘有较近的亲缘关系。最近几年,在内蒙古二连盆地不同地点和层位采集到数量丰富的戴氏貘化石,其中包括头骨和头后骨骼材料。本文即是对其中采自沙拉木伦地区乌兰胡秀地点全脊貘(Teleolophus)头后骨骼的研究报告,材料包括前足、后肢及后足。通过对全脊貘头后骨骼的形态描述,以及和相关类群(Deperetella,Lophialetes,Heptodon,Helaletes和Colodon)的比较,表明全脊貘属和戴氏貘属具有很多相似特征,支持了两者具有较近的亲缘关系。这些特征主要包括长而纤细的四肢,后足三趾;月骨较长而窄,其近端桡骨关节面内侧缘略凹;巨骨近端的头状隆起位置靠前,外侧具有和Mc IV的关节面;股骨滑车略微不对称;腓骨非常退化,甚至和胫骨愈合;Mt III与骰骨关节;Mt II主要在后方与外楔骨关节。虽然全脊貘头后骨骼也有一些和脊齿貘(Lophialetes)相似的特征,但考虑到两者臼齿上明显的区别,它们在骨骼上的相似特征可能归因于平行演化的结果。和全脊貘相比,Colodon的头后骨骼和Heptodon的更为接近,表明后两者具有更近的亲缘关系。但戴氏貘科在貘超科中的系统发育位置以及和沼貘科(Helaletidae)的亲缘关系,仍需进一步的研究工作。形态特征和后肢的"三元图"分析都表明,全脊貘已经具有较为快速的奔跑能力,这和同时期的脊齿貘相似。     

云南昭通水塘坝中新世末期古猿化石点的云南貘化石(英文)

此前,中国晚中新世到早上新世的貘化石发现较为稀少。最近几年,在云南省昭通市水塘坝禄丰古猿化石点发现了数量可观的中新世晚期貘化石,其时代为6~6.5 Ma。新发现材料包括左上颌骨带P2-M2、4件下颌骨带基本完整颊齿列、若干零散牙齿。新材料可归人先前报道的小型貘类——云南貘Tapirus yunnanensis。云南貘比甘肃的和政貘Tapirus hezhengensis时代较晚,体形也稍大;两者都比上新世一更新世的貘类明显较小。新发现的化石材料对更全面认识云南貘的特征提供了新信息。在中一晚中新世期间,云南是我国貘类动物的演化中心,先后发现的化石点有开远(小龙潭)、禄丰(石灰坝)、元谋(小河、竹棚、雷老)、昭通(水塘坝)及其他地点。在晚新生代期间,我国貘类动物演化的主要变化趋势是体形逐渐增大,这一特点或许具有时代意义。在中国发现的中新世貘类毫无例外都是体形较小的类型,这与欧洲及北美的情况迥异。     

封面说明

<正>貘类动物于始新世起源于北美地区,后来成为美洲和欧亚大陆特有动物;但在其演化历史中,在北美和欧洲地区都存在一个中中新世的化石记录间断(tapir vaccum),而我国却是当时地球上仅存貘类动物的地区;因此,云南貘及其近亲很有可能是晚新生代貘类动物的直接祖先。云南貘比现今的马来貘体型稍小,但其骨骼和牙齿结构却与现代貘已十分接近,尤其是和亚洲地区的化石貘     

山东昌乐早始新世五图相脊齿貘类（貘超科）

脊齿貘类是亚洲特有的中，晚始新世貘形动物，在中始新世很繁盛，但一直未发现早始新世种类，山东五图早始新世地层中发现的山东兼脊貘。很可能是这一类群的早期代表，它与中始新世已知种具有某些共有的特点，但仍有主午餐我是如新世原始貘类的特征，同时，本简单地回顾了脊齿貘类研究历史，根据现有的材料，概述了脊齿貘类的特征，根据一些进步特征将已知属分别归于脊齿貘科和红山貘科。     

犀貘(哺乳纲,奇蹄目,貘超科)化石在垣曲盆地的发现

记述了在山西省垣曲盆地发现的犀貘一新种———童氏犀貘 (Hyrachyustongisp .nov .)。它的发现揭示了在垣曲盆地有中中始新世地层存在的可能性。还对以往在中国境内发现的犀貘化石做了简要评述     

内蒙古二连盆地早始新世脑木根组上部的奇蹄类(英文)

描述了内蒙古二连盆地脑木根组上部(早始新世伯姆巴期)两种奇蹄类:脊齿貘类的二连明镇貘(新属新种)Minchenoletes erlianensisgen.et sp.nov.和蹄齿犀类的Pataecops parvus。二连明镇貘区别于其他脊齿貘类的特点是:个体小,颊齿齿冠低,齿脊相对不发育,牙齿较横宽(长宽比小),M3相对较长。两种化石分别将脊齿貘科和犀超科的化石记录提前到最早始新世。最新的地层资料表明,明镇貘仅发现于脑木根组上部,相当于伯姆巴期的地层中;施氏貘(Schlosseria)和脊齿貘(Lophialetes)则分别发现于阿山头组和伊尔丁曼哈组。因此,这些化石在生物地层对比和早期奇蹄类演化研究中具有重要价值。依据二连地区的新资料和中亚考察团的野外记录,我们认为蒙古的Pataecops parvus标本可能来自比Kholobolchi动物群大多数种类更低的层位,可能相当于伯姆巴期。     

新研究显示云南昭通古猿分布区曾是貘类动物演化中心

貘类动物起源于北美始新世早期,体型较小,后来发展为美洲和欧亚大陆特有动物.我国晚中新世到早上新世的貘化石发现很稀少.1978年,北京自然博物馆时墨庄等人在云南一四三煤田地质队的协助下在昭通永乐褐煤矿采掘到一批哺乳动物化石,他们依据其中的几件貘化石下颌骨残段建立一新种——云南貘,并认为其地质时代为距今250万年至300多万年的晚上新世.但当时这一发现没有得到足够重视,导致野外和室内研究工作中断多年.     

封面说明

马来貘(Tapirus indicus),奇蹄目,犀形亚目,貘科;是现存4种貘中唯一分布在旧大陆的种类,也是它们中体型最大的一种。体长1.8~2.5 m,肩高0.9~1.1 m,体重250~540 kg。成兽黑白相间,幼兽棕色密布白色纵纹,有如小野猪。分布在泰国西部、缅甸东南部、马来半岛、苏门答腊岛中南部,此外在柬埔寨可能还有一个小种群。栖息于海     

闪闪发光的貘

正"咕噜噜",溪水里冒出一串葡萄似的泡泡,亮晶晶的,闪着五颜六色的光。一只肥嘟嘟的貘从泡泡下钻了出来。它甩甩脑袋上的水,舒服地哈了一口气。突然,它的身后传出"咕咚"一声巨响,吓得这只叫墨墨貘的貘赶紧钻回水里。过了好一会儿,它才小心翼翼地再次探出水面。"好可怕!"墨墨貘小声嘟哝。而造成刚才巨大声响的罪魁祸首——一颗成熟后掉进水里的木瓜,则被一群饥饿的小鱼快速分食。     

Assessing occupancy and habitat connectivity for Baird’s tapir to establish conservation priorities in the Sierra Madre de Chiapas,Mexico

Baird’s tapir (Tapirus bairdii) is the largest native mammal that inhabits the Neotropics, and it is enlisted as Endangered by the IUCN Red List. The historic distribution of this species included the area from southern Mexico to northern Colombia. However, its distribution and populations have been reduced drastically during the past 30 years. The main threats for Baird’s tapir are the direct persecution for subsistence hunting, habitat destruction, and habitat fragmentation. In this study, we used camera traps and occupancy models to identify the landscape characteristics that were associated with the occurrence of tapirs in the Sierra Madre de Chiapas, which is one of the most important populations of the species in Mexico, with the aim to identify areas with habitat suitability for the species. We used our best occupancy model to generate a resistance matrix to develop a model of habitat connectivity using Circuit Theory. According to the best occupancy model, the most suitable areas for this species were the forested areas located at the highest elevations of the mountain ranges that provided rugged terrain. We identified three critical corridors to allow for the connectivity of tapir populations in the Sierra Madre de Chiapas, and one of these corridors provides connectivity between this population and the population in the Ocote Biosphere Reserve. With this approach, we propose a conservation strategy for the species that incorporates a more realistic and detailed scheme of Baird’s tapir occurrence in the Sierra Madre de Chiapas region. Priority actions to conserve tapirs in the Sierra Madre de Chiapas over the long term include ensuring the complete protection of prime habitat for the species, improved connectivity by protecting forest cover, implementation mitigation measures in areas where paved roads interrupt connectivity of populations, and eradicating poaching of the species in the region completely.     

Cloning of Clostridium perfringens alpha-toxin gene and extracellular expression in Escherichia coli]

Clostridium perfringens (C. perfringens) is a Gram-positive bacterial pathogen that widely propagets in the soil and the gastrointestinal tract of human and animals. This bacteria causes food poisoning, gas gangrene and other various range of infectious diseases. But there is no standard diagnosis method of C. perfringens. In order to develop a new type of immunoassay for clinical purpose, we studied expression and extracellular secretion of recombinant alpha-toxin having enzyme activity in E. coli expression system. Cloning was carried out after PCR amplification from C. perfringens GAI 94074 which was clinical isolate. Three kinds of fragment were cloned using pET100/D-TOPO vector. These fragments coded for ribosome binding site, signal peptide, and alpha-toxin gene respectively. Recombinant pET100 plasmid transformed into TOP 10 cells and the obtained plasmids were transformed into BL21 (DE3) cells. Then, the transformants were induced expression with IPTG. In conclusion, we successfully cloned, expressed and exteracellular secreted C. perfringens alpha-toxin containing signal peptide. Biologically, the obtained recombinant protein was positive for phospholipase C activity.     

A型产气荚膜梭菌经小鼠传代的毒力变化

目的:探讨A型产气荚膜梭菌经小鼠腹腔传代后的毒力变化。方法:选择10只小鼠,腹腔注射浓度为5.0×108 cfu/mL的A型产气荚膜梭菌菌液1 mL,记录第一代小鼠存活时间;收集第一代死亡最早的小鼠腹腔内的细菌,经血平板厌氧培养24 h后配制5.0×108 cfu/mL浓度的菌液,并腹腔注射10只小鼠,每只1 mL,记录第二代小鼠存活时间;重复实验并记录第三代、第四代小鼠的存活时间;死亡小鼠腹腔收集的细菌以革兰染色涂片镜检,血平板培养,用API 20A试剂条进行生化鉴定;用SPSS 13.0软件分析每代小鼠的存活时间组间差异。结果:小鼠腹腔收集的标本经革兰染色后均可见两端钝圆棒状的革兰阳性杆菌,血平板厌氧培养均为边缘呈锯齿状有双溶血环的较大菌落,API 20A的结果为产气荚膜梭菌;小鼠存活时间随小鼠腹腔传代数不断延长,第一代与第二代、第三代、第四代之间的存活时间差异有统计学意义,第二代、第三代与第四代两两之间的存活时间差异无统计学差异。结论:A型产气荚膜梭菌经小鼠腹腔第一次传代后毒力显著减弱,随后传代中毒力基本不变,与传统的细菌经动物腹腔培养后毒力增强的观点不一致。     

Growth of Clostridium perfringens in Food Proteins Previously Exposed to Proteolytic Bacilli

Proteolytic sporeforming bacteria capable of surviving processing heat treatments in synthetic or fabricated protein foods exhibited no antagonistic effects on growth of Clostridium perfringens, but instead shortened the lag of subsequent growth of C. perfringens in sodium caseinate and isolated soy protein. Bacillus subtilis A cells were cultured in 3% sodium caseinate or isolated soy protein solutions. The subsequent effect on the lag time and growth of C. perfringens type A (strain S40) at 45 C was measured by colony count or absorbance at 650 nm, or both. B. subtilis incubation for 12 h or more in sodium caseinate reduced the C. perfringens lag by 3 h. Incubation of 8 h or more in isolated soy protein reduced the lag time by 1.5 h. Molecular sieving of the B. subtilis-treated sodium caseinate revealed that all molecular sizes yielded a similar reduced lag time. Diethylaminoethyl-Sephadex ion exchange fractionation and subsequent amino acid analysis indicated that the lag time reduction caused by B. subtilis incubation was not related to charge of the peptides nor to their amino acid composition. Apparently the shortened C. perfringens lag in these B. subtilis-hydrolyzed food proteins was a result of the protein being more readily available for utilization by C. perfringens.     

Prevalence of enterotoxigenic Clostridium perfringens Isolates in Pittsburgh (Pennsylvania) area soils and home kitchens

In the United States and Europe, food poisoning due to Clostridium perfringens type A is predominantly caused by C. perfringens isolates carrying a chromosomal enterotoxin gene (cpe). Neither the reservoir for these isolates nor the point in the food chain where these bacteria contaminate foods is currently understood. Therefore, the current study investigated whether type A isolates carrying a chromosomal cpe gene are present in two potential reservoirs, i.e., soil and home kitchen surfaces. No C. perfringens isolates were recovered from home kitchen surfaces, but most surveyed soil samples contained C. perfringens. The recovered soil isolates were predominantly type A, but some type C, D, and E soil isolates were also identified. All cpe-positive isolates recovered from soil were genotyped as type A, with their cpe genes on cpe plasmids rather than the chromosome. However, two cpe-positive soil isolates did not carry a classical cpe plasmid. Both of those atypical cpe-positive soil isolates were sporulation capable yet failed to produce C. perfringens enterotoxin, possibly because of differences in their upstream promoter regions. Collectively these results suggest that neither soil nor home kitchen surfaces represent major reservoirs for type A isolates with chromosomal cpe that cause food poisoning, although soil does appear to be a reservoir for cpe-positive isolates causing non-food-borne gastrointestinal diseases.     

产气荚膜梭菌实时荧光PCR方法的建立

目的:利用荧光定量PCR技术,建立快速敏感特异的检测产气荚膜梭菌的方法。方法:以产气荚膜梭菌基因为靶序列设计引物和探针,以自产气荚膜梭菌菌株中提取的DNA为模板,优化引物和探针的浓度比,同时验证方法的特异性、敏感性。结果:建立的反应体系在上游引物浓度为0.45μmol/L、下游引物浓度为0.15μmol/L、探针浓度为0.3μmol/L时,具有良好的特异性和敏感性,与创伤弧菌等12种相关细菌均无交叉反应;对纯菌检测的灵敏度低于10 CFU/反应体系。结论:建立的实时荧光PCR方法特异、灵敏、快速,能对战时气性坏疽做出快速准确的报告,实现对这种战时高发疾病的安全、快速和定量检测。     

Serologic properties of strains of Cl. perfringens isolated from the intestinal contents of healthy subjects]

A study was made of the quantitative content in the intestine of C1. perfringens strains in 6 healthy persons who stayed in a hermetically sealed space for 1 month and for 1 year. C1. perfingens strains were isolated from the fecal samples of each of the volunteers at various periods of the trial. A total of 570 strains of C1. perfringens of type A with anticellular sera obtained to the strains of various serological groups were studied. Serological properties of C1. perfringens strains of type A present in the intestinal contents of man were nonhomogeneous. This pointed to the simultaneous presence in the intestine of strains belonging to several serological types. A partial or complete replacement of one strain by another (differing by serological properties) occurred in the course of not over one month. C1. perfringens strains of type A present in the intestine of each volunteer were subdivided into serological types individual for each of the persons under observation. This pointed to the fact than no interexchange of strains of the mentioned bacteria occurred between different persons in the hermetically sealed space.     

Identification of glucose-fermenting bacteria present in an in vitro model of the human intestine by RNA-stable isotope probing

16S rRNA-based stable isotope probing (SIP) and nuclear magnetic resonance (NMR) spectroscopy-based metabolic profiling were used to identify bacteria fermenting glucose under conditions simulating the human intestine. The TIM-2 in vitro model of the human intestine was inoculated with a GI tract microbiota resembling that of the small intestine, to which subsequently 4, 20 or 40 mM of [U-(13)C]-glucose were added. RNA was extracted from lumen samples after 0 (control), 1, 2 and 4 h and subjected to density-gradient ultracentrifugation. Phylogenetic analysis of unlabeled 16S rRNA revealed a microbial community dominated by lactic acid bacteria and Clostridium perfringens. Distinct (13)C-incorporation into bacterial RNA was only observed for the 40-mM addition. 16S rRNA fingerprinting showed an activity drop of Lactobacillus fermentum after glucose addition, while Streptococcus bovis and C. perfringens were identified as the most active glucose-fermenters. Accordingly, NMR analysis identified lactate, acetate, butyrate and formate as the principal fermentation products, constituting up to 91% of the (13)C-carbon balance. RNA-SIP combined with metabolic profiling allowed us to detect differential utilization of a general model carbohydrate, indicating that this approach holds great potential to identify bacteria involved in the fermentation of dietary relevant oligo- and polymeric carbohydrates in the human intestine.     

Detection by in vitro amplification of the alpha-toxin (phospholipase C) gene from Clostridium perfringens

A polymerase chain reaction (PCR) with thermostable DNA polymerase from Thermus aquaticus is described for the specific amplification of the phospholipase C (alpha-toxin) gene of Clostridium perfringens. A set of primers selected for their high specificity could detect Cl. perfringens in stools with a detection limit of approximately 5 x 10² bacteria, after bi-amplification. A modified PCR without thermal steps was performed to rapidly amplify, with a yield of 60%, the DNA template. With this PCR method Cl. perfringens alpha-toxin gene could be detected within 2 h. The PCR method detected alpha-toxin positive Cl. perfringens but did not react with phospholipase C-producing Bacillus cereus, Pseudomonas aeruginosa, Cl. sordellii and Cl. bifermentans.
The amplified PCR products were screened through ethidium bromide agarose gel electrophoresis or, in only 1 h, with the PhastSystem (Pharmacia). This PCR satisfies the criteria of specificity, sensitivity and rapidity required for a useful tool in epidemiology and for the diagnosis of the pathogen Cl. perfringens as it may be used directly on stool samples.