Evolution of conserved secondary structures and their function in transcriptional regulation networks

Background: Many conserved secondary structures have been identified within conserved elements in the human genome, but only a small fraction of them are known to be functional RNAs. The evolutionary variations of these conserved secondary structures in h

Molecular evolution of the keratin associated protein gene family in mammals, role in the evolution of mammalian hair

Background: Hair is unique to mammals. Keratin associated proteins (KRTAPs), which contain two major groups: high/ultrahigh cysteine and high glycine-tyrosine, are one of the major components of hair and play essential roles in the formation of rigid and

Avoidant Learning Ability in Free Flying Housefly (Aldrichina grahami)by Electric Shock

下载PDF阅读器研究证实:蜜蜂和果蝇具有良好的学习记忆能力.利用自主改良的研究装置对另一种具有强大生存本能的双翅目昆虫--巨尾阿丽蝇(Aldrichina grahami)在自由状态下电击同避学习能力进行研究.结果表明,巨尾阿丽蝇具有良好的学习记忆能力,因为当刺激电压范围为5V到45V时,观察到巨尾阿丽蝇有显著的回避电刺激行为,而当电压达到60V时会受到明显伤害.由此推测,巨尾阿丽蝇适合作为神经系统研究的动物模型.该实验所采用的实验范例较以往有所改进,适合作为自由状态下研究昆虫的工具.

Effects of extremely low-frequency electromagnetic fields on morphine-induced conditioned place preferences in rats

In the present study, we examined the effects of extremely low-frequency (ELF) electromagnetic fields on morphine-induced conditioned place preferences in rats. During the conditioning phase (12 days), three groups of rats were placed in a sensory cue-defined environment paired with morphine (10 mg/kg, i.p.) following exposure to either 20 Hz (1.80 mT) or 50 Hz (2.20 mT) or sham electromagnetic fields for 60 min/day, respectively, and were placed in another sensory cue-defined environment paired with physiological saline (1 ml/kg, i.p.) without exposure to electromagnetic fields. After finishing 12 days of conditioning, preference tests for the morphine-paired place were performed during a 10-day withdrawal period. The exposure to electromagnetic fields substantially potentiated morphine-induced place preferences in rodents, suggesting that ELF electromagnetic fields can increase the propensity for morphine-induced conditioned behaviors. (C) 2005 Elsevier Ireland Ltd. All rights reserved.

Effects of exposure to 50 Hz magnetic field of 1 mT on the performance of detour learning task by chicks

In the present study, we examined the effects of exposure to an extremely low-frequency magnetic field of 1 mT intensity on learning and memory in Lohmann brown domestic chicks using detour learning task. These results show that 20 h/day exposure to a low

Extremely low-frequency electromagnetic field exposure during chronic morphine treatment strengthens downregulation of dopamine D2 receptors in rat dorsal hippocampus after morphine withdrawal

The aim of this study was to investigate the effect of extremely low-frequency electromagnetic field (ELF-EMF) exposure during morphine treatment on dopamine D2 receptor (D2R) density in the rat dorsal hippocampus following withdrawal. Rats were exposed t

Influence of physical parameters of sound on the sensory gating effects of N40 in rats

Sensory gating is the ability of the brain to modulate its sensitivity to incoming stimuli. The N40 component of the auditory evoked potential, evaluated with the paired click paradigm, was used to probe the gating effect in rats. The physical characteris

Effects of various extenders and permeating cryoprotectants on cryopreservation of cynomolgus monkey (Macaca fascicularis) spermatozoa

The cryoprotective effects of 11 different extenders, TTE, DM, mDM, LG-DM, G-DM, TCG, TEST, TSM, Test-M, Test-H, and LM, on sperm cryopreservation of cynomolgus monkey (Macaca fascicularis) have been compared with glycerol as cryoprotectant. Sperm motility, plasma membrane, and acrosomal integrity were examined to evaluate frozen-thawed sperm function. The results showed that TTE, DM, mDM, LG-DM, G-DM, and TCG exhibited the best and similar protective efficiencies for cynomolgus monkey sperm cryopreservation in terms of sperm motility and plasma membrane integrity (P > .05). The acrosomal integrity for spermatozoa cryopreserved in TCG was statistically lower than that of TTE, DM, mDM, LG-DM, and G-DM (P < .05) but was significantly higher than that of TEST, TSM, Test-M, Test-H, and LM (P < .05). The postthaw sperm motility for 5 other extenders (TEST, TSM, Test-M, Test-H, and LIVI) did not exceed 30%, and the 3 sperm parameters evaluated for them were significantly lower than that of TTE, DM, mDM, LG-DM, G-DM, and TCG (P < .05). On the basis of these findings, 5 commonly used permeating cryoprotectants, glycerol, ethylene glycol, dimethyl sulfoxide, acetamide and propylene glycol have further been tested for their effectiveness on sperm cryopreservation in extenders of TTE, DM, mDM, LG-DM, G-DM, and TCG. The results showed that the sperm cryoprotective efficiencies of glycerol and ethylene glycol were similar and best among 5 permeating cryoprotectant treatments (P > .05). Dimethyl sulfoxide or acetamide resulted in average cryoprotection for cynomolgus monkey spermatozoa: poorer than glycerol or ethylene glycol but better than that of propylene glycol (P < .05). In addition, the action of permeating cryoprotectant appeared to be independent of extenders. The results in the present study demonstrate that 1) TTE, DM, mDM, LG-DM, G-DM, and TCG are excellent extenders and suitable for cynomolgus monkey sperm cryopreservation; 2) the mechanism of action of permeating cryoprotectants are not affected by extender composition; 3) ethylene glycol has a similar cryoprotective efficacy to glycerol that makes it a successful cryoprotectant for sperm cryopreservation in cynomolgus monkeys.

Comparative studies with six extenders for sperm cryopreservation in the cynomolgus monkey (Macaca fascicularis) and rhesus monkey (Macaca mulatta)

Ejaculated spermatozoa from cynomolgus monkeys and rhesus monkeys were frozen in straws with six different extenders (TTE, DM, mDM, LG-DM, G-DM, and TCG) containing glycerol. Sperm motility and head membrane and acrosomal integrity were evaluated after fr

鸡胚背根神经节培养法测定神经生长因子(NGF) 活性的条件优化

目的　探索一套稳定可靠的鸡胚背根神经节测定N GF 活性的实验条件。　方法　通过观察培养 基、鸡血浆和鸡胚浸液的比例、背根神经节部位、培养时间等条件对N GF 刺激神经节生长的影响, 从而 建立一套该培养法检测N GF 活性的优化条件。　结果　以DM EM 为母液, 在含20% 鸡血浆和15% 鸡胚 浸液的培养基中, 利用伊莎褐鸡胚腰椎背根神经节, 在终浓度为30 ngöm l 的蛇毒N GF 的刺激下, 培养36h 可以得到较好的实验结果。　结论　该条件简单实用、分辨率高、重复性好。

不同有机溶剂萃取生物结皮中叶绿素a效率的比较研究

参照水体中浮游植物叶绿素a的萃取测定方法,运用丙酮、乙醇、二甲基甲酰胺(DMF)、二甲基亚砜(DM-SO)4种有机溶剂对不同土质不同发育阶段自然和人工生物结皮中叶绿素a的萃取效率进行了比较研究。结果发现,不同有机溶剂从生物结皮中萃取叶绿素a的效率存在极显著差异(P<0.001),而乙醇法的离散度最低;取样量对萃取效率总体上没有显著影响(P>0.05),但在具体的测定中与萃取效率之间存在负相关。4种方法中,DMSO法对藻类占优势的结皮萃取率最高,DMF法对自然结皮的萃取率仅次于DMSO法,在人工结皮中最低;

马氏珠母贝Dmrt5基因的克隆及时序表达模式分析

Dmrt(Double sex and Mab-3 related transcription factor)基因是一类含有高度保守的DM(Double sex and Mab-3)结构域的基因家族,该基因家族的很多成员都参与了性别决定和分化过程的调控。目前已研究了很多物种的Dmrt基因,但对于具有重要进化地位和经济价值的贝类,却鲜见相关报道。Dmrt5作为Dmrt基因家族的重要成员,是否也参与了动物的性别决定与分化的调控,至今为止没有定论。采用RACE-PCR技术,从马氏珠母贝(Pinctadamate

Optimum temperature for the growth performance of juvenile orange-spotted grouper (Epinephelus coioides H.)

Effects of water temperature (17, 21, 25, 30 and 35 degrees C) and body size (14.75-281.41 g initial body weight) on food consumption, growth, feed conversion, and dry matter content in orange-spotted grouper fed to satiation were investigated. The combined effect of temperature (T, degrees C) and body weight (W, g) on maximum food consumption (C-max, g/day) was described as: InCmax= -7.411+0.828 lnW+0.317T-0.004 7T(2), and the optimum feeding temperature was 33.9 degrees C. The combined effect of temperature and body weight on growth (G) was described as: InG= -4.461-0.208lnW+0.394T-0.006 3T(2). The optimum growth temperature was 31.4 degrees C, whereas overall growth rates were high at 25, 30 and 35 degrees C. Feed conversion efficiencies (FCE, %), increasing first and then decreasing with increasing temperature, averaged from 1.8 to 2.1 in terms of dry weight of food fish. The optimum temperature for FCE tended to be lower than that for growth or feeding. Dry matter content increased with both increasing water temperature (17, 25, 30 and 35 degrees C) and body weight, and the combined effect of temperature and body weight on dry matter content (DM, %) was described as: lnDM =3.232+0.01 4 lnW-0.004 4T+0.001 2TlnW.

A conserved family of doublesex-related genes from fishes

The sex-determining gene Mab-3 of C. elegans and the doublesex gene of Drosophila each contain a common DM domain and share a similar role. Human doublesex-related gene DMRT1 also encodes a conserved DM-related DNA-binding domain. We present here the amplification of a broad range of DM domain sequences from three fish species using degenerate PCR. Our results reveal unexpected complexity of the DM domain gene family in vertebrates. (C) 2002 Wiley-Liss, Inc.