虎斑颈槽蛇行为的观察

本文报道了虎斑颈槽蛇的行为。虎斑颈槽蛇一般栖息在水域附近。在辽宁省西部地区,１０月份陆续进入冬眠,翌年４月醒眠。以无尾两栖动物为食,采用偷袭和伏击方式捕食。有回缩、逃遁、藏匿和威吓等反捕行为。     

虎斑颈槽蛇小肠发育的组织学研究

本文对虎斑颈槽蛇孵化出壳后一月内的幼蛇小肠组织结构做了较为系统的观察,结果显示,在孵化出壳的一个月内,小肠的组织结构呈现明显的变化。主要表现在绒毛的个数、绒毛高度、粘膜上皮细胞高度、粘膜下层厚度和肌层厚度等均随幼体日龄的增加而显著增加。其中,开口前、后(即孵化出壳后十天左右),其小肠组织结构变化最为显著。     

黄淮平原虎斑颈槽蛇的繁殖策略

野生虎斑颈槽蛇在繁殖期的栖息地选择、产卵、孵化、幼蛇的形态变化和行为等方面皆有其独特的适应策略。     

虎斑颈槽蛇毒液伤眼1例报告

<正>我区地处皖南山区,气候温和,自然条件适宜蛇类生长,蛇类种群繁多。其中以虎斑颈槽蛇分布较广,在我区黄山、青阳、祁门、东至等地均为优势种之一,主要生活于山区、丘陵、平原,常出没玉米地、路边、菜地、水沟边及近水、潮湿的草地等。曾有文献报道,该蛇颈部可分泌毒液,也有临床报道该蛇咬伤人案例发生[1]。我院近年来每年收治毒蛇咬伤患者近100例,但唯一收治1例虎斑颈槽蛇毒液致伤眼患者,现将结果报告如下。     

虎斑颈槽蛇Sox基因的克隆及测序

参照人SRY基因HMG-box保守区序列设计一对兼并引物,PCR扩增虎斑颈槽蛇的Sox基因,采用SSCP技术筛选阳性克隆,并对其进行了测序。结果表明：在雌雄个体中共筛选出3个Sox基因,其中一个为雄性独有,显示出性别差异性,3个Sox基因DNA序列及编码的氨基酸序列与人相应SOX3,SOX11,SOX22基因的相似性分别为91%,92%,91%和98%,96%,96%。显示出高度的保守性,实验结果为虎斑颈槽蛇的性别决定机制研究提供了分子资料。     

虎斑颈槽蛇多态与变异

目的研究虎斑颈槽蛇大陆亚种[Phabodophis tigrinus lateralis (Berthold)]在不同分布地区存在的多态现象和变异性。方法在分析已经报道的有关文献的基础上,研究辽宁、吉林等地野外采集到的标本,并对虎斑颈槽蛇大陆亚种的色斑变异和腹鳞的多态现象进行相关分析结果虎斑颈槽蛇大陆亚种的腹鳞数目与纬度呈强正相关,与经度呈中等正相关,与年均温度呈强负相关,与体长呈弱相关关系,年均温度高产卵时间早,而孵化时间长。结论分布范围相对较窄的蛇腹鳞数目是相对稳定的,分布范围广、跨越纬度大,腹鳞的数目差异亦很大。     

虎斑颈槽蛇大陆亚种的一些生物学资料

1990～2007年,对虎斑颈槽蛇的生活习性、生长发育、产卵、孵化条件和胚胎发育进行了观察研究.虎斑颈槽蛇的产卵期为6月～7月中旬,一年一次性产卵6～22枚, 孵化期为41～43天,胚胎发育分为16期.卵产出时胚胎已发育到第10～11期,孵化至37天时仔蛇已基本发育完全.详细描述了11～16期胎蛇的外部形态特征和发育时序.     

室温条件下虎斑颈槽蛇卵的孵化与幼蛇饲养

目的探讨室温条件下虎斑颈槽蛇的孵化及幼蛇饲养情况。方法选用同一条虎斑颈槽蛇产的同窝蛇卵31枚,随机为A组（实验组）、B组（对照组）,A组16枚,B组15枚。两组蛇卵分别置于2个完全相同的打孔整理箱中进行孵化,孵出幼蛇用小泽蛙饲养。结果在室温条件下,孵化期58天,孵化率为96．77％。出壳后7～9天,幼蛇第1次蜕皮,蜕皮周期在11～16天不等。结论对虎斑颈槽蛇进行工厂化人工养殖是切实可行的。     

中国境内虎斑颈槽蛇大陆亚种的形态学研究

蛇类的外部形态在分类和系统研究中具有重要的作用,利用蛇类大量外部形态特征的统计分析来探讨广泛分布物种的种下分类问题,已被证实是可行的。本研究首次将该方法应用于中国的广布物种Rhabdophis tigrinus lateralis,探讨该种在我国的分类和地理居群分布,为R.tigrinus这一物种分类研究提供更多的形态数据。     

虎斑颈槽蛇脑一氧化氮合酶NADPH-d组织化学定位研究

运用NADPH—d组织化学方法,对虎斑颈槽蛇脑的一氧化氮合酶进行了定位研究。结果表明：阳性反应主要位于脑的大脑半球、视上核、室旁核、联合下器官、内侧纵束、室旁灰质、蓝斑以及网状结构等区域,比较讨论了与其他脊椎动物的异同。分析一氧化氮作为神经信号分子除了参与各类动物共有的一些机能的调节以外,不同类群或种类中还参与某些特定生理功能的调节。     

温度对虎斑颈槽蛇消化酶活性的影响

研究了不同温度下虎斑颈槽蛇胃、胰腺、小肠的蛋白酶、淀粉酶、脂肪酶的活性。结果表明,随着温度的升高,各种酶的活性在一定范围之内均表现为升高。在不同组织中同一种酶活性存在差异。3种组织中,蛋白酶的最适温度均为40℃;胃和胰腺淀粉酶的最适温度为35℃,小肠淀粉酶为30℃;胰腺脂肪酶的最适温度为30℃,小肠脂肪酶为35℃。     

颈槽蛇的地理变异

地理变异是蛇类中较为常见的现象。颈槽蛇Rhabdophis nuchalis在中国具有广泛的地理分布,是研究地理变异的理想物种。统计分析采自中国各地的61号颈槽蛇标本外部形态特征,对其地理变异模式进行了研究。结果表明:来自云南省高黎贡山的种群与其他种群在眶后鳞数、腹鳞数、上唇鳞黑纹的数量和后颔片间是否有小鳞等形态特征上的差异有统计学意义。     

爬行动物肾性节的研究概述

肾性节是一种雄性副性结构,主要存在于爬行动物双孔亚纲Diapsida鳞龙下纲Lepidosauria,尤其是有鳞目的雄性,由肾脏的集合管前端或肾单位的远曲小管末端膨大特化而成.肾性节的细胞由柱状上皮细胞组成,胞质中充满电子致密的分泌颗粒.组织化学研究表明,肾性节呈ACP、AKP、糖原、糖蛋白、脂类和蛋白质等反应阳性,且存在种间差异.肾性节的细胞大小和超微结构具有明显的年周变化,并与生殖腺的发育密切相关.此外,某些蛇和蜥蜴的雄性幼体具有肾性节,而在某些种类的雌性也具有类似的结构.有关这一结构的生理功能尚不完全清楚,曾有学者提出几种假设:具有支持和激活精子的作用,形成交配栓,与精液形成有关或提供求爱信息素等.     

Comparative experimental tests of natricine antipredator displays, with special reference to the apparently unique displays in the Asian genus, Rhabdophis

Nuchal glands are unique organs known in only twelve Old World natricine species (three genera) including Rhabdophis tigrinus tigrinus. The glands of R. t. tigrinus contain a toxic secretion that may be derived from its toxic toad diet. A series of peculiar antipredator behaviors, for example neck arch, neck butt, and dorsal-facing posture, are exhibited by R. t. tigrinus, and a functional association between this behavior and the nuchal glands has been suggested. To investigate the ubiquitousness of these putatively unique displays among snakes, antipredator responses of 27 taxa of natricine snakes, both with and without nuchal glands, were studied using a common testing procedure. Three of four taxa with nuchal glands exhibited neck arch, neck butt, and dorsal-facing posture. None of the remaining 23 taxa, which do not possess the glands, showed neck arch and neck butt. Principal-components analysis indicated the association of the above three displays along with the behaviors termed neck flatten and head elevation, confirming the presence of a series of nuchal gland-related behaviors. These results support the assumption that the suite of peculiar displays is associated with the deterrent effects of the nuchal gland secretion.     

Inter-species hybridization among Neotropical cats of the genus Leopardus, and evidence for an introgressive hybrid zone between L. geoffroyi and L. tigrinus in southern Brazil

Natural hybrid zones between distinct species have been reported for many taxa, but so far, few examples involve carnivores or Neotropical mammals in general. In this study, we employed mitochondrial DNA (mtDNA) sequences and nine microsatellite loci to identify and characterize a hybrid zone between two Neotropical felids, Leopardus geoffroyi and L. tigrinus, both of which are well-established species having diverged from each other c. 1 million years ago. These two felids are mostly allopatric throughout their ranges in South America, with a narrow contact zone that includes southern Brazil. We present strong evidence for the occurrence of hybridization between these species and identify at least 14 individuals (most of them originating from the geographical contact zone) exhibiting signs of interspecific genomic introgression. The genetic structure of Brazilian L. tigrinus populations seems to be affected by this introgression process, showing a gradient of differentiation from L. geoffroyi correlated with distance from the contact zone. We also corroborate and extend previous findings of hybridization between L. tigrinus and a third related felid, L. colocolo, leading to an unusual situation for a mammal, in which the former species contains introgressed mtDNA lineages from two distinct taxa in addition to its own.     

Embryonic growth and mobilization of energy and material in oviposited eggs of the red-necked keelback snake, Rhabdophis tigrinus lateralis

We used the red-necked keelback (Rhabdophis tigrinus lateralis) as a model animal to study embryonic growth and mobilization of energy and material in oviposited snake eggs. Females (N=12) laid eggs between late May and early June. Eggs were incubated at 30 (+/-0.3) degrees C. One egg from each clutch was dissected at five-day intervals starting at oviposition. Incubation length averaged 27.9 days. Three phases of embryonic growth or yolk depletion could be detected in this study. The first phase, between oviposition and Day 10, was one of minimal transfer of energy and material from yolk to embryo. The second phase, between Day 10 and Day 22-23, was characterized by increasingly rapid embryonic growth and yolk depletion. The third phase, between Day 22-23 and hatching, was characterized by a gradual reduction in embryonic growth and yolk depletion. Approximately 73.6% of dry mass, 50.0% of non-polar lipids and 57.8% of energy were transferred from egg to embryo during incubation. Embryos withdrew mineral from the eggshell mainly during the last quarter of incubation. Our data show that oviposition does not coincide with the onset of rapid embryonic growth in oviparous species of squamate reptiles that are positioned midway within the oviparity-viviparity continuum, and that the greater conversion efficiencies of energy and material from egg to hatchling in snakes can be mainly attributed to their lower energetic costs of embryonic development and greater residual yolk sizes.     

Sexual selection,redundancy and survival of the most beautiful

A model is described of a highly redundant complex organism that has overlapping banks of genes such that each vital function is specified by several different genetic systems. This generates a synergistic profile linking probability of survival to the number of deleterious mutations in the genome. Computer models show that there is a dynamic interaction between the mean number of new deleterious mutations per generation (X), the mean number of deleterious mutations in the genome of the population (Y) and percentage zygote survival (Zs). IncreasedX leads to increasedY and a fall in Zs but it takes several generations before a new equilibrium is reached. If sexual attraction is influenced by the number of deleterious mutations in the genome of individuals thenY is reduced and Zs increased for any given value ofX. This fall inY and rise in Zs is more marked in polygamous than monogamous mating systems. The model is specified such that deleterious mutations can occur without any observable or measurable effect on function. Thus sexual selection, in this organism, for low levels of deleterious mutations cannot be based on assessment of performance. Instead it is based on a simple symmetrical surface pattern that is flawlessly reproduced by organisms with no deleterious mutations, but is less than perfect, and therefore less attractive, if genetic systems have been deleted. A complex vital task requires a system with a high level of redundancy that acts so that the loss of one component has no observable effect and therefore cannot be used for sexual selection. The reproduction of a beautiful surface pattern also requires a low error, high redundancy genetic system; however, in this case there is advantage if a single deleterious mutation produces a recognisable change. This leads to the conclusion that sexual selection and sexual attraction should be based on beauty rather than utility, and explains the common observation in nature that it is the most beautiful that survive.     

西藏小型猪肾脏应用组织学特点

目的研究西藏小型猪肾脏的组织结构,为其在生物医药领域中的应用提供形态学依据。方法取西藏小型猪肾脏标本投入10%中性福尔马林溶液固定24 h以上,修块,冲洗,脱水,透明,包埋,常规石蜡切片,HE染色,光镜观察拍照。结果西藏小型猪的肾与人肾一样呈长而扁的菜豆形,是表面光滑的多乳头肾,肾的表面有致密的结缔组织构成的被膜,肾实质可分为皮质和髓质,由数百万个肾单位和泌尿小管组成,其间由少量结缔组织、血管和神经等构成肾间质。结论西藏小型猪的肾脏结构比犬和猴更接近于人类,在异种器官移植、药物临床前安全性评价等生物医药领域中具有重要应用前景。