一种简易的另啮齿动物切趾编码方法

提出一套改进的切趾樗编码系统。该编码系统具有趾号易于判读、切趾分布均匀的优点。本套编号系统具有一定的兼容性,可根据样地内动物个体的数量选择最小的切趾数,从而尽可能减少切趾对小哺乳动物行为与生存的影响。     

实验小鼠标记识别系统的优化

传统的实验小鼠标记识别系统包括染色法、打孔剪口法、刺花法、耳标签法和剪趾法等。随着小鼠作为动物模型在实验中广泛应用,人们对实验标记识别系统提出了简捷、易辨、持久、大编码量的新需求。本优化系统利用简单的数学方法改进剪趾法,使编码量扩大到9999,针对不同实验需求提供不同选择,并且在遵循动物福利的理念下,提出了一些建议。     

ENU诱变获得一种多趾小鼠及其突变基因的鉴定

采用化学诱变剂乙酰基亚硝基脲(N-ethyl-N-nitrosourea,ENU)获得一种常染色体显性遗传多趾突变小鼠(Mus musculus),该突变小鼠在后趾内侧(即轴前部)多出一个脚趾,且严重程度不一,部分小鼠双侧后足都有多趾表型。阿尔新蓝-茜素红染色结果表明,多趾突变杂合子小鼠除多趾异常发育外,其余骨骼无明显异常。为定位该突变基因,利用微卫星标记对(C57BL/6J×DBA/2J)F1代多趾突变小鼠回交C57BL/6J得到的[(C57BL/6J×DBA/2J)F1×C57BL/6J]N2代多趾小鼠进行全基因组扫描,最终将本例多趾突变基因定位于小鼠第2号染色体微卫星D2mit45与D2mit184之间,并初步确定Alx4为该突变候选基因。在此基础上对Alx4进行测序分析,测序结果发现突变小鼠Alx4基因编码区第433位碱基处发生A到T的颠换,导致编码区第145位密码子AAA(编码赖氨酸)变为终止密码子TAA,引起蛋白编码提前终止,是引起多趾表型的原因。     

内含子编码蛋白与内含子的转移

具有自我剪接能力的Ⅰ型和Ⅱ型内含有编码蛋白质的功能,Ⅰ型内含子编码成熟酶和核酸内切酶,后者参与Ⅰ型与含子的归巢。Ⅱ型内含子编码的蛋白质呈现成熟酶核酸内切酶和逆转录酶活性,三种活性都在Ⅱ型内含子归巢中和用。     

内含子编码蛋白与内含子的转移

具有自我剪接能力的Ⅰ型和Ⅱ型内含子有编码蛋白质的功能。Ⅰ型内含子编码成熟酶和核酸内切酶,后者参与Ⅰ型内含子的归巢。Ⅱ型内含子编码的蛋白质呈现成熟酶核酸内切酶和逆转录酶活性,三种活性都在Ⅱ型内含子归巢中起作用。除归巢外,Ⅰ型和Ⅱ型内含子的转移还表现为转位和丢失。内含子作为可转移遗传因子,可能在进化中有一定的意义。     

大鼠脑α1型甲状腺激素受体基因cDNA克隆及序列分析

使用ＲＴ－ＰＣＲ方法克隆了Ｗｉｓｔａｒ大鼠脑α１型甲状腺激素受体的ｃＤＮＡ,得到包含起始及终止密码子共１２３３ｂｐ、编码４０９个氨基酸的受体全长编码离列,酶切分析后,将此特异ＤＮＡ片段重组入质粒ｐＵＣ系统,得重组质料ｐＴＲＡ。双脱氧末端终止法测定了全部核苷酸顺序。     

防止发酵细菌受噬菌体污染

有些运载体携带着保护发酵细菌不受噬菌体污染的基因,这些基因编码诸如溶血嗜血菌(Haemophilus haemolyticus)Hhall系统之类的细菌限制——修饰性的序列。它们产生限制性内切酶在限制性位点上消化噬菌体的DNA。     

真菌线粒体cob中Ⅱ型LAGLIDADG归巢内切酶进化分析

以已公布的114种真菌线粒体基因组数据为依据,对cob内含子及其编码的Ⅱ型LAGLIDADG归巢内切酶进行全面分析,以揭示其进化规律。在cob内含子中共发现27个Ⅱ型LAGLIDADG归巢内切酶基因,其中18个位于S433内含子插入位点,其余9个散布在另外8个插入位点。结合Pfam数据,将Ⅱ型LAGLIDADG归巢内切酶分成10个主要类群,其中4个类群存在不同生物界物种间的水平迁移。S433位点的18个归巢内切酶均属于类群1,它们与宿主内含子可能从共同祖先垂直遗传而来,并在传递过程中伴有水平迁移;其他归巢内切酶及宿主内含子则应是水平迁移的结果。类群1中的归巢内切酶可分为两个亚类,两亚类识别的靶序列存在明显差异;保守模体氨基酸序列分析显示它们大多数具有潜在内切酶活性。全面呈现了真菌线粒体cob内含子及其编码的Ⅱ型LAGLIDADG归巢内切酶的存在状态和进化模式,为归巢内切酶的改造和设计提供了新素材。     

人巨细胞病毒糖蛋白52kD抗原编码区段在大肠杆菌中高效表达

采用聚合酶链反应,从人巨细胞病毒重组质粒克隆pBH中扩增并分离了含糖蛋白52kD抗原编码区段;扩增产物经纯化和EcoR Ⅰ酶切后,与相同酶切的高效表达质粒pBV-220重组,构成含人巨细胞病毒糖蛋白52kD抗原编码区段的高效表达质粒pHcMV 52;用此重组表达质粒转化大肠杆菌JM101,经增殖和42℃温度诱导以及筛选。阳性克隆经12.5％SDS-PAGE表明,外源基因表达蛋白质量占菌体溶解液中蛋白质总量20％。蛋白质印迹(western blot)杂交证实该表达产物具有免疫原性。     

水稻基因组上一个Ds切离及其双位点插入行为的分子鉴定

玉米转座元件Ac/Ds是hAT转座子家族的成员, 导入水稻基因组后具有转座活性, 尽管转座机制还不完全清楚, 但它们通常经保守的非复制型“剪切-粘贴”过程转座。研究表明, 在Ac编码的转座酶作用下, Ds从原位点切离后常优先重新插入到连锁位点。文章利用TAIL-PCR技术从水稻一个Ds插入突变体及其回复突变体中分离Ds侧翼序列, 结合生物信息学分析方法, 对Ds在突变体上插入位点、回复突变体内切离足迹和重新插入位点进行了分子鉴定。结果显示, 突变体中Ds从3号染色体切离后, 在原插入位点残留了8 bp足迹序列(CATCATGA), 引起Ds标记基因外显子和内含子数目增加, 从而影响基因结构。切离后的Ds重新插入回复突变体第2和第6号染色体上, 分别编码烟草胺氨基转移酶和衰老相关蛋白的2个基因的编码区。因此, 典型的“剪切-粘贴”机制不能完全解释Ds的转座行为, Ds转座存在“剪切-复制-粘贴”的特点。     

Toe‐bud clipping of juvenile small marsupials for ecological field research: No detectable negative effects on growth or survival

Toe clipping is widely used to permanently mark many species of small vertebrates including marsupials, particularly didelphids and dasyurids. Small marsupials are marked as juveniles, by removing the tip of developing toe buds. It has recently been shown that survival and/or recapture probability decreases with increasing number of toes clipped in frogs. Because of this and other animal welfare concerns, toe clipping of adult vertebrates is increasingly being discouraged. The short‐ and long‐term effects of toe‐bud clipping have not been evaluated in marsupials. We used an experiment to test if marking more toes results in slower growth or higher mortality in the brown antechinus (Antechinus stuartii, Dasyuridae) in the short or long term. We found no harmful effects of toe‐bud clipping. There were no infections associated with clipping, marking more toes did not reduce growth in young or adults, and did not affect survival of young in captivity, survival of independent animals in the wild, or recapture probability. Toe‐bud clipping is done at an extremely immature stage, when the area cut is tiny and perception and memory of pain is unlikely to be a problem. We suggest that toe‐bud clipping is a humane and benign method of permanently marking antechinuses, and probably also the young of other morphologically similar small marsupials.     

Identification of newborn rats by tattooing

Pups were identified by toe clipping or tattooing the plantar surface of the paws on day 4 after delivery. Their growth, maturation, and reproductive capability were not affected by either identification method. In the toe clipping group, however, the duration until fall in the suspension test was significantly shortened, indicating that this identification method may not be suitable for some behavioural tests. The clipping also disturbs the skeletal investigation of toes and is not recommended from the view point of animal welfare. Palm tattooing, on the other hand, satisfies the fundamental requirements for long-term identification of rats.     

Seasonality of herbivory and communication between individuals of sagebrush

Seasonal changes in herbivore numbers and in plant defenses are well known to influence plant–herbivore interactions. Some plant defenses are induced in response to herbivore attack or cues correlated with risk of attack although seasonal variation in these defenses is relatively poorly known. We previously reported that sagebrush becomes more resistant to its herbivores when neighboring plants have been experimentally clipped with scissors. In this study we asked whether herbivory to leaves of sagebrush varied seasonally and whether there was seasonal variation in natural levels of damage when neighbors were clipped. We found that sagebrush accumulated most chewing damage early in the season, soon after the spring flush of new leaves. This damage was caused by generalist grasshoppers, deer, specialist caterpillars, beetles, gall makers, and other less common herbivores. Sagebrush showed no evidence of preferentially abscising leaves that had been experimentally clipped. Experimental clipping by Trirhabda pilosa beetle larvae caused neighbors to accumulate less herbivore damage later that season, similar to results in which clipping was done with scissors. Induced resistance caused by experimentally clipping a neighbor was affected by season; plants with neighbors clipped in May accumulated less damage throughout the season relative to plants with unclipped neighbors or neighbors clipped later in the summer. We found a correlation between seasonal herbivore pressure, damage accumulated by plants, and induced responses to experimentally clipping neighbors. The causal mechanisms responsible for this correlation are unknown although a strong seasonal effect was clear.     

Effects of clipping and soil compaction on growth,morphology and mycorrhizal colonization of Schizachyrium scoparium,a C4 bunchgrass

Summary A factorial design of clipping and compaction was used to study the responses of Schizachyrium scoparium and its mycorrhizal symbionts to these stresses. All treatment combinations significantly reduced the growth and biomass of plants relative to controls. Compaction significantly reduced tillering and crown expansion while clipping increased tillering early in the growing season and reduced it later. Mycorrhizal colonization of roots was highest in the clipped plots and lowest in compacted plots. Spore number was highest in compacted plots and lowest in clipped plots. It appears that spore number may be negatively correlated with root growth since any treatment that reduced plant growth yielded higher spore numbers. The combination of clipping and compaction reduced plant growth the most, but had intermediate effects on mycorrhizal colonization and spore number.     

Toe-clipping procedure for individual identification of rodents

A simple, easily readable system for permanent individual identification of rodents was accomplished by clipping off selected toes according to a code. Up to 10,000 animals could be consecutively numbered using this system.     

Responses of an African graminoid (Themeda triandra Forsk.) to frequent defoliation,nitrogen, and water: a limit of adaptation to herbivory

Summary Themeda triandra Forsk., a medium height perennial grass common in semi-arid Africa, was collected from Serengeti National Park in Tanzania, propagated vegetatively and grown in controlled environments simulating native conditions. The experiment demonstrated mechanisms that result in inability to withstand frequent defoliation, and thus how plant-herbivore interactions are affected by plant morpho-physiology. Clipping reduced most plant yield components. After two months leaf elongation rate was greater in clipped plants, but over the whole experiment aboveground yield was unaffected by clipping. Since clipping did not stimulate growth, residual leaf area was less in clipped plants. Tillering was not stimulated by clipping so there was no mechanism to increase leaf area below the clipping height. The resulting reduced leaf area accounted for reduced root and crown production by clipped plants.     

Coat Clipping of Horses: A Survey

Coat clipping is a common practice in sport horses; however, timing, purpose, technique, and clips vary widely, as do the management and feeding of a clipped horse. The aim of this study was to collect data regarding common clipping practices. A questionnaire was published online in Germany and contained 32 questions. Four hundred ninety-eight people answered at least one question, and 373 individuals (7% male, 93% female; ages 14–59 years) completed all the questions. Clipped horses were predominantly used as sport horses (68%), and they were either clipped immediately before or during the winter season (88%) or year-round (7%). The clipping date was scheduled according to hair length (52%), sweat amount (47%), and drying time (47%). Participants primarily used two clips: the hunter clip and the blanket clip, both without clipping the head (23% each). The majority of the clipped horses wore a blanket day and night (> 90%). Future studies with observations in the field are needed to support survey data in an effort to develop welfare recommendations for clipping practices utilized with horses.     

Secondary centers of ossification of the human toes: exceptional polymorphism and evolutionary perspectives

As great morphological variability characterizes the phalanges of the human toes in adults, we hypothesized for a possible variability in the presence or absence of their secondary (= epiphyseal) centers of ossification linked to the unique morphology of the human foot within primates. The aim of this study was thus to provide original and detailed data on the occurrence of these centers. Classically, the big toe or hallux (I) presents two secondary centers and the lateral toes (II-V) three centers, and consequently the five toes present a total of 14 secondary centers. The material studied consisted of 261 foot radiographs from 261 young individuals of European origin (202 males and 59 females; 6-16 years). The presence (or absence) of the secondary centers of the phalanges of the toes was assessed for each foot. Feet presenting a biphalangeal variant in one or more lateral toes were studied separately. The theoretical possibilities of association of the three secondary centers in a given lateral toe (II-V) are eight in number; these eight patterns were studied and coded in the present study by types A-H. An exceptional variability in the occurrence of the secondary centers in lateral toes (II-V) was observed, and the classic pattern of phalangeal ossification was never observed. The absence of one or more secondary centers seems to be observed only in the human species, and we suggest that this could be a derived pattern specific to the human species, i.e., autapomorphic pattern. These results are of interest in the characterization and understanding of the reduction in size of the lateral toes which characterizes the specific evolution of the human foot.     

漂浮育苗剪叶传播烟草丛顶病风险研究

为了评估漂浮育苗剪叶传播烟草从顶病的风险, 以剪刀剪病叶后再剪苗和剪刀蘸取病烟汁液后再剪苗2种剪叶方法研究了漂浮育苗剪叶对烟草丛顶病和烟草普通花叶病的传播效果。调查数据显示, 2种剪叶方法均不能传播烟草丛顶病, 但能传播烟草普通花叶病, 其平均发病率分别为36.67%和63.33%。实验结果表明, 漂浮育苗剪叶不易传播烟草丛顶病, 但易于传播烟草普通花叶病。     

漂浮育苗剪叶传播烟草丛顶病风险研究

为了评估漂浮育苗剪叶传播烟草从顶病的风险,以剪刀剪病叶后再剪苗和剪刀蘸取病烟汁液后再剪苗2种剪叶方法研究了漂浮育苗剪叶对烟草丛顶病和烟草普通花叶病的传播效果.调查数据显示,2种剪叶方法均不能传播烟草丛顶病,但能传播烟草普通花叶病,其平均发病率分别为36.67%和63.33%.实验结果表明,漂浮育苗剪叶不易传播烟草丛顶病,但易于传播烟草普通花叶病.