胭脂鱼胰岛素样生长因子-Ⅰ(IGF-Ⅰ)cDNA的分子克隆、序列分析及组织表达

参考多种生物的胰岛素样生长因子-Ⅰ(IGF-Ⅰ)基因序列,设计并合成引物。用胭脂鱼(Myxocyprinus asiaticus)肝总RNA逆转录得到cDNA并扩增获得特异性片段,回收纯化后亚克隆到pMD-18T载体上。测序后经序列比对分析表明,所得到的序列是胭脂鱼胰岛素样生长因子-Ⅰ(IGF-Ⅰ)cDNA片段,共489bp,包括该基因完整的开放阅读框(ORF)486bp,编码162个氨基酸。氨基酸序列与其他鲤形目鱼类具有较高的同源性,对胭脂鱼IGF-Ⅰ在一些组织中的表达研究发现,IGF-Ⅰ在肝中表达最多,其次是胰、性腺,在脑、垂体、鳃、心、脾中也有不同程度的表达,而在肠、肾、肌肉中的表达不十分明显。     

BmSE, a SINE family with 3′ ends of (ATTT) repeats in domesticated silkworm (Bombyx mori)

Short interspersed elements (SINEs), which are mainly composed of Bm1, are abundant in the domesticated silkworm. A 294 bp novel SINE family, designated as BmSE, was identified by mining the database of the complete Bombyx mori genome. A representational BmSE element is flanked by an 11 bp target site duplication sequence posterior poly (A) at the 3′ end and has the sequence motifs of an internal promoter of RNA polymerase III, which are similar to that of Bm1. The repetitive elements of BmSE are ...     

摄食水平对瓦氏黄颡鱼餐后代谢特征的影响

以新鲜泥鳅(Misgurus anguillicanndotus)肉块为饵料,采用麻醉灌喂的方法,在(25.0±0.5)℃条件下,研究了瓦氏黄颡鱼(Pelteobagrus vachelli)幼鱼[体重(7.03±0.15)g,n=42]不同摄食水平(饵料分别为体重的0%、1%、2%、4%和8%)对餐后代谢反应的影响.结果显示,在不同摄食水平下,瓦氏黄颗鱼摄食代谢均呈现先上升后下降的整体变化趋势;摄食水平由1%增加到8%,实验鱼的SDA耗能、SDA时间和摄食代谢峰值(PMR)分别从3.09 kJ/kg、8 h和56.08 mg O_2/kg·h增加到47.21 kJ/kg、36 h和97.25 mgO_2/kg·h;其中,8%(饱足摄食水平)和4%摄食水平组的代谢率在峰值水平能够持续20 h左右.瓦氏黄颡鱼最大运动代谢率(MMR)为166.5 mg O_2/kg·h,显著大于饱食组PMR(P＜0.05).本研究还表明,随摄食水平上升,瓦氏黄颡鱼通过PMR的增加和SDA时间的延长来满足SDA耗能增加的需求;从摄食4%组和8%组相似的梯形摄食代谢曲线,可以看出瓦氏黄颡鱼在高摄食水平条件(＞4%)下限制了摄食代谢的上升;PMR相对于静止代谢上升倍率较小,暗示其摄食占据的代谢空间较小,进而保留了大量剩余代谢空间用于运动和其他生理活动,这可能与其活跃的觅食活动习性有关.     

Identification of NbME MITE families: Potential molecular markers in the microsporidia Nosema bombycis

Six novel families of miniature inverted-repeat transposable elements (MITEs) were characterized in the microsporidia Nosema bombycis and were named NbMEs. The structural characteristics and the distribution of NbME copies in the N. bombycis genome were investigated, and it was found that portions of NbMEs are associated with gene sections. Potential molecular markers for various N. bombycis strains were identified in this study through utilization of the MITE-AFLP technique. Three distinct pathogenic isolates collected from different areas were distinguished, and polymorphisms were detected using the NbME5 marker, thereby establishing this NbME as a potential marker for studying isolate variation in N. bombycis.     

Four copper(II) coordination polymers with a tetrachlorinated benzenedicarboxylate ligand: Solvent effect on diversiform supramolecular arrays

To further investigate the solvent effect on the structures of coordination polymers, a series of polymeric Cu^II complexes have been synthesized and characterized by single-crystal diffraction through combining of 2,3,5,6-tetrachloro-1,4-benzenedicarboxylic acid (H₂BDC-Cl₄) with Cu^II perchlorate. The products including {[Cu(BDC-Cl₄)(py)₃] · H₂O}_n (py = pyridine) (1), {[Cu(BDC-Cl₄)(dioxane)(H₂O)₂] · dioxane}_n (2), and {[Cu₂(BDC-Cl₄)₂(DMF)₄] · 2G}_n (G = MeOH in 3 and G = EtOH in 4) have been obtained in different mixed solvents systems. With the change of the solvent system from pyridine/H₂O (1:1) into dioxane/H₂O (1:1), the infinite 1-D Cu^II-BDC-Cl₄ chain motif in 1 is tuned into the 2-D (4,4) layered structure in 2 with the coordination of dioxanes to copper atoms. When the solvent system is changed into DMF/MeOH (1:1), then into DMF/EtOH (1:1), similar 1-D Cu^II-BDC-Cl₄ double chains are afforded in 3 and 4 with different solvents inclusion. Moreover, the judicious choice of binding-guests leads to numerous coordination geometries of Cu^II centers and final dissimilar supramolecular lattices of 1-4 from 1-D to 3-D via robust hydrogen-bonding interactions. The spectroscopic, thermal, and fluorescent properties of 1-4 have also been investigated.     

Natural selection maintains the transcribed LTR retrotransposons in Nosema bombycis

Eight intact LTR retrotransposons(Nbr1?Nbr8)have been previously characterized from the genome of Nosema bombycis,a eu-karyotic parasite with a compact and reduced genome.Here we describe six novel transcribed Nbr elements(Nbr9?Nbr14)identified through either cDNA library or RT-PCR.Like previously determined ones,all of them belong to the Ty3/Gypsy superfamily.Retrotransposon diversity and incomplete domains with insertions(Nbr12),deletions(Nbr11)and in-frame stop codons in coding regions(Nbr9)were detected...     

重庆喀斯特地区现代花粉组合与植被的关系

重庆喀斯特地区4种不同地貌单元的81份表土和苔藓样品的孢粉分析结果表明:(1)研究区植物孢粉组合共由109科属组成。除金佛山外,其他植被退化严重地区样点均以草本和蕨类植物占据优势(剔除石漠化治理大量引种的马尾松、柳杉和侧柏等乔木花粉),其次是乔木植物花粉(主要为马尾松),灌木植物花粉含量很低,显示该区植被退化严重;(2)孢粉组合的PCA分析能够很好地将研究区的现代孢粉组合区分开来,较好地反映了重庆喀斯特地区不同地貌单元的植被特征,特别是石漠化区植被退化严重的孢粉组合特征。生态保护较好、自然植被发育的金佛山地区具有106科属的乔木、灌木与草本孢粉类型,以及高含量的乔木花粉,而喀斯特石漠化地区的鸡公山(46科属)、青木关镇(56科属)和南平镇(50科属)则表现为乔灌木孢粉类型较少;(3)银杉作为金佛山特有的孑遗植物,其花粉含量明显低于松属花粉,说明其花粉不利于远距离传播;(4)随着土地利用强度的增加,现代孢粉组合中乔灌木花粉含量和种类越少,草本和蕨类植物孢粉含量越多,且以耕地杂草为主。因此,土地利用方式的变化是喀斯特石漠化区次生植被及其现代孢粉组合变化的主要影响因素。研究可为重庆喀斯特地区土地利用策略的制定,重庆及其周边地区第四纪古植被、古气候和古环境重建研究,以及中国孢粉数据库建设提供基本数据和科学依据。     

Synthesis and stability assay of 4-methylumbelliferyl (1→3)-β-D-pentaglucoside

The synthesis and stability of 4-methylumbelliferyl (1 → 3)-β-D-pentaglucoside 3 are described. The (1 → 3)-β-D-glucan isolated from the cell walls of Saccharomyces cerevisiae was recovered from the aqueous medium as water-insoluble particles by the spray drying (GS) method. The acid-solubilized (1 → 3)-β-D-oligoglucosides were prepared by partial acid hydrolysis of glucan. The peracetylated (1 → 3)-β-D-pentaglucoside 1 was obtained by isolation of peracetylated (1 → 3)-β-D-oligoglucoside mixture. The peracetylated 4-methylumbelliferyl (1 → 3)-β-D-pentaglucoside 2 was synthesized by treating compound 1 with the 4-methylumbelliferone and a Lewis acid (SnCl₄) catalyst. NaOMe in dry methanol was used for the deacetylation of the blocked derivative, to give the target compound 3 in an overall yield of 35%. Activity assays with β-glucosidase indicated that compound 3 was much more stable than the corresponding pentasaccharide.     

The effects of temperature and exercise training on swimming performance in juvenile qingbo (Spinibarbus sinensis)

To investigate the effects of temperature and exercise training on swimming performance in juvenile qingbo (Spinibarbus sinensis), we measured the following: (1) the resting oxygen consumption rate $ \left( {{\dot{\text{M}}\text{O}}_{{ 2 {\text{rest}}}} } \right) $ , critical swimming speed (U _crit) and active oxygen consumption rate $ \left( {{\dot{\text{M}}\text{O}}_{{ 2 {\text{active}}}} } \right) $ of fish at acclimation temperatures of 10, 15, 20, 25 and 30 °C and (2) the $ \dot{M}{\text{O}}_{{ 2 {\text{rest}}}} $ , U _crit and $ \dot{M}{\text{O}}_{{ 2 {\text{active}}}} $ of both exercise-trained (exhaustive chasing training for 14 days) and control fish at both low and high acclimation temperatures (15 and 25 °C). The relationship between U _crit and temperature (T) approximately followed a bell-shaped curve as temperature increased: U _crit = 8.21/{1 + [(T ? 27.2)/17.0]²} (R ² = 0.915, P < 0.001, N = 40). The optimal temperature for maximal U _crit (8.21 BL s^?1) in juvenile qingbo was 27.2 °C. Both the $ \dot{M}{\text{O}}_{{ 2 {\text{active}}}} $ and the metabolic scope (MS, $ \dot{M}{\text{O}}_{{ 2 {\text{active}}}} - \dot{M}{\text{O}}_{{ 2 {\text{rest}}}} $ ) of qingbo increased with temperature from 10 to 25 °C (P < 0.05), but there were no significant differences between fish acclimated to 25 and 30 °C. The relationships between $ \dot{M}{\text{O}}_{{ 2 {\text{active}}}} $ or MS and temperature were described as $ {\dot{\text{M}}\text{O}}_{{ 2 {\text{active}}}} = 1,214.29/\left\{ {1 + \left[ {\left( {T - 28.8} \right)/10.6} \right]^{2} } \right\}\;\left( {R^{2} = 0.911,\;P < 0.001,\;N = 40} \right) $ and MS = 972.67/{1 + [(T ? 28.0)/9.34]²} (R ² = 0.878, P < 0.001, N = 40). The optimal temperatures for $ \dot{M}{\text{O}}_{{ 2 {\text{active}}}} $ and MS in juvenile qingbo were 28.8 and 28.0 °C, respectively. Exercise training resulted in significant increases in both U _crit and $ \dot{M}{\text{O}}_{{ 2 {\text{active}}}} $ at a low temperature (P < 0.05), but training exhibited no significant effect on either U _crit or $ \dot{M}{\text{O}}_{{ 2 {\text{active}}}} $ at a high temperature. These results suggest that exercise training had different effects on swimming performance at different temperatures. These differences may be related to changes in aerobic metabolic capability, arterial oxygen delivery, available dissolved oxygen, imbalances in ion fluxes and stimuli to remodel tissues with changes in temperature.     

Effect of fasting and repeat feeding on metabolic rate in Southern Catfish,Silurus meridionalis chen

Southern catfish juvenile (37.6-65.9 g) were fasted for two weeks and fed with cutlets of freshly killed loach species at 2% body mass per meal twice daily (06:00 and 18:00) for four days at 27.5°C. Metabolic rates were measured during the fasting and feeding periods and all metabolic rates were adjusted to a standard body mass of 1 kg using an exponent of 0.75. The aim of this study was to investigate the effect of fasting and repeat feeding on the resting metabolic rate and the feeding metabolic rate. The results demonstrated that the standardized value of the resting metabolic rate gradually decreased from 69.6 ± 2.7 (means ± S.E.) to 42.8 ± 2.3 mgO2 h-1 during the two weeks of fasting. The peak feeding metabolic rate and average metabolic rate of each feeding (12 h) gradually increased with repeat feeding before leveling off. The results of this study suggest that southern catfish can regulate digestive function and gradually alter the characteristics of metabolism according to the availability of a food resource.