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71.
黑龙江小兴安岭地区黄鼬夏冬季毛皮性状比较 总被引:3,自引:0,他引:3
Coat characteristics of seasonal molting mammals reveal significant seasonal variation as an adaptive strategy to cope with seasonal climate changes. However, the adaptive significance of such morphological variation has not yet been addressed. We analyzed seasonal variation of microscopic indices of hair and skin of adult Siberian weasels (Mustela sibirica manchurica Brass) from the Tonghe forest area of the Xiaoxing’anling Mountains, Heilongjiang. Skins from 8 males and 8 females were collected from summe... 相似文献
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Since first large-scale attempts to culture sturgeon from the larval stage were carried out in the former U.S.S.R. at the end of the nineteenth century, rearing technology has advanced considerably during the last 20 years and noticeable improvements in incubation and larval rearing techniques have been implemented in normal hatchery procedures. Siberian sturgeon eggs are incubated in MacDonald jars at 13–14° C to prevent fungal infections. Mass hatching takes place 7 days after fertilization and hatching rate can be predicted as a function of the percentage of eggs fertilized. Survival at the end of the endogenous feeding stage is correlated with hatching rate. Egg size has no direct implications for larval growth and survival of Siberian sturgeon. Experimental studies have demonstrated that behavioural observations are useful criteria to assess the quality of larvae and to synchronize the physiological state of fish with the appropriate rearing procedures. Special attention should be given to the transition to exogenous feeding, where cannibalism, difficulties in adaptation to a new diet, overfeeding and resulting bacterial infections dramatically reduces survival to the fingerling stage. Although a commercial artificial diet specifically formulated for larvae of Siberian sturgeon and other acipenserids is still lacking, commercial non-purified rainbow trout diets and starter marine fish diets are currently used and their results are reasonably acceptable in terms of larval growth and survival. Further research must be focused on the determination of egg quality indicators in order to provide the producer with the tools to estimate the viability and performance of theprogeny. 相似文献
74.
Shell microstructures of the Early Cambrian Anabarella and Watsonella as new evidence on the origin of the Rostroconchia 总被引:1,自引:0,他引:1
ARTEM V. KOUCHINSKY 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1999,32(2):173-180
Internal moulds of the laterally compressed monoplacophoran Anabarella plana Vostokova, 1962, and likely earliest rostroconch Watsonella Grabau, 1900, from the Early Cambrian of the Siberian Platform, show similar microstructures. The moulds are covered with a thin phosphatic crust replicating the inner morphology and microstructure of the shells. The shells were completely removed during etching of the samples in 10% acetic acid, except for some moulds of Watsonella sp., which retained an incompletely preserved and recrystallized wall. Three types of microtexture were found in moulds of Anabarella and Watsonella : polygonal, spiny and step-wise. The polygonal texture is well exposed in the apical area and dorsal margin and is interpreted to represent a prismatic outer layer. The polygons can be partially overlapped by spiny and stepwise textures that may represent a crossed-lamellar inner layer. Prisms and lamellae were first-order structural units, probably consisting of fibers. The similar shell microstructures of Anabarella and Watsonella , especially at the dorsal margins, support the hypothesis that a laterally compressed monoplacophoran such as Anabarella plana was the first evolutionary step from monoplacophorans towards Early Cambrian bivalves via the earliest rostroconch-like Watsonella. 相似文献
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76.
《Peptides》2016
Urocortin-3 (UCN3), one of the corticotropin releasing factor (CRF) family peptides, which was discovered in 2001, has a variety of biological functions. However, the researches of UCN3 in fish were scarce. In order to understand whether UCN3 play a role in regulating food intake in fish, we first cloned the ucn3 cDNAs sequence of Siberian sturgeon (Acipenser baerii Brandt), and investigated the ucn3 mRNA levels in 11 tissues. The Siberian sturgeon ucn3 cDNA sequence was 1044 bp, including an open reading frame (ORF) of 447 bp that encoded 148 amino acids with a mature peptide of 40 amino acids, a 5ʹ-terminal untranslated region (5ʹ-UTR) of 162 bp and a 3ʹ-terminal untranslated region (3ʹ-UTR) of 435 bp. The result of tissue distribution showed that ucn3 widely distributed in 11 tissues with highest expression in brain. We also assessed the effects of periprandial (pre- and post-feeding), fasting and re-feeding on ucn3 mRNAs abundance in brain. The results showed the expression of ucn3 mRNA in brain was significantly elevated after feeding, decreased after fasting 17 days and increased after re-feeding. To further investigate the food intake role of UCN3 in Siberian sturgeon, we performed intraperitoneal (i.p.) injection of Siberian sturgeon UCN3 (SsUCN3) with three doses (60, 120 or 240 ng/g) and recorded the food intake. Acute and chronic i.p. injection SsUCN3 reduced the food intake in a dose-dependent pattern. In conclusion, this study indicates that SsUCN3 acts as a satiety factor to inhibit the food intake of Siberian sturgeon. 相似文献
77.
范文静张颖张舒董翠霞李明波范文慧 《现代生物医学进展》2014,14(2):336-339
目的:探讨医患通平台对经皮冠状动脉介入治疗(PCI)术后患者进行护理的临床效应。方法:选取54例冠心病行PCI治疗术后患者,随机分为对照组和试验组,各27例。对照组采用常规护理,试验组在对照组的基础上采用医患通平台进行护理干预,比较两组患者血压、血脂、血糖的控制情况,主要不良心脏事件(MACE)的发生情况,并采用汉密尔顿焦虑量表(HAMA)及汉密尔顿抑郁量表(HAMD)对两组患者进行心理状况调查。结果:实施干预后,试验组血压、血脂、血糖的控制率优于对照组(P0.05),MACE的发生率低于对照组(P0.05);两组患者两组干预前HAMA、HAMD评分比较无明显差异(P0.05),干预后试验组患者HAMA评分、HAMD评分有所下降,与干预前及对照组比较差异显著(P0.01),对照组干预前后无变化(P0.05)。结论:医患通平台能有效地让PCI术后患者对危险因素进行控制,降低MACE的发生,改善患者的负性情绪,是较好的健康教育方式。 相似文献
78.
Xiang Wei Ran Zhao Ying-Hui Sun Jian-Ping Cong Fan-Guo Meng 《Journal of enzyme inhibition and medicinal chemistry》2013,28(1):234-240
The present work focused on the kinetics of the inhibitory effects of the leaf extract of Siberian Crabapple, named Shan jingzi in China, on chicken liver fatty acid synthase. The results showed that this extract had much stronger inhibitory ability on fatty acid synthase than that from green teas described in many previous reports. The inhibitory ability of this extract is closely related to the extracting solvent, and the time of extraction was also an important influencing factor. The inhibitory types of this extract on diffeerent substrates of chicken liver fatty acid synthase, acetyl-CoA, malonyl-CoA and NADPH, were found to be noncompetitive, uncompetitive and mixed, respectively. The studies here shed a new light on the exploration for inhibitors of fatty acid synthase. 相似文献
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Suppression of kisspeptin expression and gonadotropic axis sensitivity following exposure to inhibitory day lengths in female Siberian hamsters 总被引:2,自引:0,他引:2
Mason AO Greives TJ Scotti MA Levine J Frommeyer S Ketterson ED Demas GE Kriegsfeld LJ 《Hormones and behavior》2007,52(4):492-498
To avoid breeding during unsuitable environmental or physiological circumstances, the reproductive axis adjusts its output in response to fluctuating internal and external conditions. The ability of the reproductive system to alter its activity appropriately in response to these cues has been well established. However, the means by which reproductively relevant cues are interpreted, integrated and relayed to the reproductive axis remain less well specified. The neuropeptide kisspeptin has been shown to be a potent positive stimulator of the hypothalamo-pituitary-gonadal (HPG) axis, suggesting a possible neural locus for the interpretation/integration of these cues. Because a failure to inhibit reproduction during winter would be maladaptive for short-lived female rodents, female Siberian hamsters (Phodopus sungorus) housed in long and short days were examined. In long "summer" photoperiods, kisspeptin is highly expressed in the anteroventral periventricular nucleus (AVPV), with low expression in the arcuate nucleus (Arc). A striking reversal in this pattern is observed in animals held in short, "winter" photoperiods, with negligible kisspeptin expression in the AVPV and marked staining in the Arc. Although all studies to date suggest that both populations act to stimulate the reproductive axis, these contrasting expression patterns of AVPV and Arc kisspeptin point to disparate roles for these two cell populations. Additionally, we found that the stimulatory actions of exogenous kisspeptin are blocked by acyline, a gonadotropin-releasing hormone (GnRH) receptor antagonist, suggesting an action of kisspeptin on the GnRH system rather than pituitary gonadotropes. Finally, females held in short day lengths exhibit a reduced response to exogenous kisspeptin treatment relative to long-day animals. Together, these findings indicate a role for kisspeptin in the AVPV and Arc as an upstream integration center for reproductively relevant stimuli and point to a dual mechanism of reproductive inhibition in which kisspeptin expression is reduced concomitant with reduced sensitivity of the HPG axis to this peptide. 相似文献