鳄蜥的食物识别机制

鳄蜥(Shinisaurus crocodilurus)食物识别机制的研究,对进一步了解鳄蜥的捕食行为和生态学习性有重要意义。使用棉棒分别沾上去离子水、香水、黄粉虫(Tenebriomolitor L.)和蚯蚓(Pheretima sp.)的气味(蚯蚓和黄粉虫处死后绞碎以便于棉花棒蘸上),观察11只鳄蜥对4种化学刺激的反应,每个个体对每种刺激均进行24次实验重复。实验结果显示：鳄蜥对4种刺激均有反应,对黄粉虫和蚯蚓刺激的舔舌次数显著高于香水和去离子水的舔舌次数(Wilcoxon test,所有P<0.001),表明鳄蜥能检测以及识别控制刺激和食物刺激。再又对鳄蜥进行4种处理实验：(A)空白对照;(B)蚯蚓气味;(C)密封着的活蚯蚓;(D)活蚯蚓。每个个体每种处理均进行5次实验。结果显示：鳄蜥在不同处理下的行为持续时间、探究频次和攻击频次有显著差异(Friedman test,所有P<0.001)。鳄蜥在仅有视觉刺激出现的处理C以及既有化学刺激又有视觉刺激的处理D比仅有化学刺激的处理B在持续时间、探究频次和攻击频次上显著要高（所有P<0.001）。在无视觉刺激的条件下,鳄蜥在处理B的行为持续时间以及探究频次均显著高于处理A 的（所有P<0.001）;而在视觉信息相同的条件下,鳄蜥在处理D中仅行为持续时间显著高于处理C（Z=3.95, P<0.001）,而探究频次以及攻击频次无显著差异（前者Z=1.53, P=0.13;后者Z=1.10, P=0.27）。结果表明鳄蜥主要利用视觉捕食,化学感觉有辅助作用。鳄蜥这种食物识别机制可能与捕食模式和种系发生有关,也可能受食物的影响。     

Developmental competence and ultrastructural changes of heat-stressed mouse early blastocysts produced in vitro

Mouse early blastocysts were exposed to temporatures of 39℃ and 41℃ for 2 h,respectively,to determine their developmental competence and uhrastructural changes. The results showed that heat stress at 41 ℃ for 2 h,significantly reduced the percentages of expanded and hatched blastocysts,but not at 39℃ for 2 h. The average cell numbers in expanded blastocysts,which developed from early blastocysts heat-stressed at temperatures of 39℃ and 41 ℃,were significantly reduced. The average cell numbers in hatched blastocysts subjected to heat stress were no different from those in the control group cultured at 37℃ . The mitochondria of the early blastocysts heat-stressed at 39T℃ for 2 h,were slightly swollen,but they had recovered after culturing at 37℃ for 2 h. However,the mitochondria in the blastocysts heat stressed at 41 ℃ for 2 h were severely swollen,and their number increased. The ribosomes shed from the rough endoplasmic reticulum,and the number of secondary lysosomes in the plasma increased. The integrity of desmosomes was disrupted. The space between the nuclear envelope and the perivitelline membrane enlarged. The fibre fraction and the particulate fraction of nucleoli were separated. The heterochromatin in nucleoli was also increased in its quantity. There were some lamellar-shape structures and heterogeneous dense materials exhibiting in the cytoplasm. The ultrastructural changes induced by heat shock at 41 ℃ for 2 h were not reversible. In conclusion,the damage of heat stress to mitochondria,lysosomes,ribosomes and cell nucleus,may be one of the most important factors that inhibit the normal development of mouse early blastocysts.     

Microhabitat use by white-footed mice Peromyscus leucopus in forested and old-field habitats occupied by Morrow's honeysuckle Lonicera morrowii

We quantified microhabitat use by white-footed mice Peromyscus leucopus in forest and old-field habitats occupied by Morrow's honeysuckle Lonicera morrowii, an invasive exotic shrub imported from Japan. Microhabitat characteristics were compared between trails used by mice (n=124) and randomly selected trails (n=127) in 4 study plots located at Fort Necessity National Battlefield, Farmington, Pennsylvania, USA. We compared 10 microhabitat variables between used and random trails using non-metric multidimensional scaling (NMDS) and classification and regression tree (CART) analysis. Trails used by mice were statistically different from randomly selected trails in both forested plots (P<0.008) and old-field plots (P<0.001). In the forested plots, trails of white-footed mice were more often associated with a greater percent cover (% cover) of coarse woody debris (CWD) than were randomly selected trails. In the old-field plots, mouse trails were commonly characterized by having a lower % cover of exotic herbaceous vegetation, a greater % cover of shrubs, and a greater % cover of Morrow's honeysuckle than randomly selected trails. Our study indicates that white-footed mice do not move randomly and prefer areas of high structural complexity, thereby showing significant microhabitat preference. The preference of white-footed mice for areas with a relatively high percent cover of Morrow's honeysuckle could 1) be a factor in the aggressive nature of the exotic honeysuckle shrub's spread throughout the Battlefield or 2) cause the shrub to spread even faster into adjacent areas not yet occupied by Morrow's honeysuckle[Current Zoology 55(2):111-122,2009].     

Temperature acclimation affects thermal preference and tolerance in three Eremias lizards(Lacertidae)

We acclimated adult males of three Eremias lizards from different latitudes to 28℃,33℃ or 38℃ to examine whether temperature acclimation affects their thermal preference and tolerance and whether thermal preference and tolerance of these lizards correspond with their latitudinal distributions.Overall,selected body temperature(Tsel)and viable temperature range(VTR)were both highest in E.brenchleyi and lowest in E.multiocellata,with E.argus in between;critical thermal minimum(CTMin)was highest in E.multiocell...     

Mating behavior induces changes of expression of Fos protein,plasma testosterone and androgen receptors in the accessory olfactory bulb (AOB) of the male mandarin vole Microtus mandarinus

In order to investigate the neuroendocrine mechanism of the mating behavior in the adult male mandarin voles Microtus mandarinus,the radioimmunoassay(RIA)and immunohistochemistry methods were used to investigate the differences in plasma testosterone(T)concentrations and distribution of T immunoreactive neurons(T-IRs),androgen receptor immunoreactive neurons(AR-IRs)and Fos protein immunoreactive neurons(Fos-IRs)in the accessory olfactory bulb(AOB)and the main olfactory bulb(MOB)following exposure to clean h...     

A Quantitative Assay for Measuring of Bovine Immunodeficiency Virus Using a Luciferase-based Indicator Cell Line

In order to quantitate the bovine immunodeficiency virus (BIV) infection in vitro, a BIV indicator cell line (BIVL) was established by transfecting baby hamster kidney cells with reporter plasmids containing the firefly luciferase gene driven by a BIV long terminal repeat promoter. The BIV activates promoter activity of the LTR to express luciferase upon infection. BIV infection could therefore by quantified by detection of luciferase activity. Compared to standard assays used to detect BIV infection, the B...     

Serial Expression of the Truncated Fragments of the Nucleocapsid Protein of CCHFV and Identification of the Epitope Region

The Crimean-congo hemorrhagic fever virus(CCHFV)is a geographically widespread fatal pathogen. Identification of the epitope regions of the virus is important for the diagnosis and epidemiological studies of CCHFV infections.In this study,expression vectors carrying series truncated fragments of the NP(nucleocapsid protein)gene from the S fragment of CCHFV strain YL04057 were constructed.The recombinant proteins were expressed in E.coli and purified for detection.The antigenic of the truncated fragments of ...     

大花酢浆草的组织培养与快速繁殖

以大花酢浆草（Oxalis bowiei）鳞茎为外植体,对适合大花酢浆草生长的培养基进行筛选,并建立了大花酢浆草的无性繁殖体系。结果表明,丛生芽诱导及增殖的最适培养基为MS＋0.25mg·L^–1NAA,继代苗在MS培养基中生根效果最好。     

水稻窄叶突变体nal（t）的表型分析与基因定位

在水稻（Oryza sativa）缙恢10号的EMS诱变群体中发现一个窄叶突变体nal（t）,表现出叶片变窄不变短、植株半矮化、节间变细变短和穗长缩短等特性。突变体苗期和成熟期叶片平均宽度为0.99cm和1.42cm,分别为野生型的76%和74%,均达到极显著差异。nal（t）成熟期倒一、倒二、倒三节间长和宽分别为9.16cm、6.97cm、3.57cm和0.31cm、0.36cm、0.45cm,仅为野生型的63%、83%、71%和78%、72%、79%。遗传分析表明该突变性状受1对隐性核基因控制,利用SSR标记将NAL（T）定位在第12染色体长臂RM6869和RM28537之间,遗传距离分别为3.1cM和9.0cM。     

壳聚糖及其衍生物抗菌性质的研究进展

壳聚糖对多种细菌、真菌具有广谱抗菌的功能,因此它被广泛地应用于广泛地用于口腔疾病、皮肤炎症、伤口感染、胃肠道疾病等各种疾病的治疗。本文综述了壳聚糖及其衍生物对常见的口腔致病菌、皮肤癣菌、伤口感染菌以及胃肠道疾病的致病菌的抗菌作用和壳聚糖及其衍生物的抗菌机理。