The mitochondrial genome of the quiet-calling katydids, <Emphasis Type="Italic">Xizicus fascipes</Emphasis> (Orthoptera: Tettigoniidae: Meconematinae)

To help determine whether the typical arthropod arrangement was a synapomorphy for the whole Tettigoniidae, we sequenced the mitochondrial genome (mitogenome) of the quiet-calling katydids, Xizicus fascipes (Orthoptera: Tettigoniidae: Meconematinae). The 16,166-bp nucleotide sequences of X. fascipes mitogenome contains the typical gene content, gene order, base composition, and codon usage found in arthropod mitogenomes. As a whole, the X. fascipes mitogenome contains a lower A+T content (70.2%) found in the complete orthopteran mitogenomes determined to date. All protein-coding genes started with a typical ATN codon. Ten of the 13 protein-coding genes have a complete termination codon, but the remaining three genes (COIII, ND5 and ND4) terminate with incomplete T. All tRNAs have the typical clover-leaf structure of mitogenome tRNA, except for tRNA(Ser(AGN)), in which lengthened anticodon stem (9 bp) with a bulged nuleotide in the middle, an unusual T-stem (6 bp in constrast to the normal 5 bp), a mini DHU arm (2 bp) and no connector nucleotides. In the A+T-rich region, two (TA)n conserved blocks that were previously described in Ensifera and two 150-bp tandem repeats plus a partial copy of the composed at 61 bp of the beginning were present. Phylogenetic analysis found: i) the monophyly of Conocephalinae was interrupted by Elimaea cheni from Phaneropterinae; and ii) Meconematinae was the most basal group among these five subfamilies.     

不同列当抗性的向日葵品种根系分泌物对向日葵列当种子萌发的影响

以对向日葵列当抗性不同的向日葵幼苗为材料,利用水培法收集其根系分泌物,经二氯甲烷萃取后结合硅胶柱色谱分离法,研究不同列当抗性的向日葵品种根系分泌物对向日葵列当种子萌发的影响。结果表明:(1)在一定浓度范围内,向日葵根系分泌物对向日葵列当种子萌发具有低浓度促进、高浓度抑制的作用;二氯甲烷萃取的向日葵根系分泌物浓度为0.1mg/mL时,其向日葵列当萌发率高于其他浓度的作用。(2)‘星火大白边’和‘白葵杂9号’根系分泌物提取物作用下向日葵列当萌发率最高分别为46.92%和43.88%,显著高于免疫品种‘MGS’根系分泌物提取物作用下列当的萌发率(27.81%)。(3)根系分泌物提取物正己烷-乙酸乙酯1∶1洗脱组分的萌发刺激活性显著高于其他组分,‘星火大白边’、‘白葵杂9号’和‘MGS’的该组分作用下向日葵列当最高萌发率分别为49.90%、45.66%和30.00%。(4)‘MGS’的根系分泌物提取物与GR24或脱氢木香内酯共同作用时种子萌发率显著低于GR24或脱氢木香内酯的单独作用,说明‘MGS’根系分泌物中可能含有抑制GR24或脱氢木香内酯刺激向日葵列当种子萌发的物质,使其对向日葵列当表现出免疫特性。     

羊草贮藏性物质含量的季节变化及其对不同人为活动影响的反应

羊草(Leymus chinensis)是根茎性禾草,是东北及内蒙东部地区广泛分布的主要建群种之一。以羊草为建群种的羊草群落分布广、面积大、是优良的天然草场。羊草草场的产草量与植物的地下部特别是根茎中贮藏性物质的含量有密切关系。因为多年生根茎性植物所制造的光合产物,除用于当年的生长发育之外,同时将多余的贮藏性物质(主要指可溶性糖     

Identification and characterization of a new member of serpin family- HongrES1 in rat epididymis

A full length cDNA named HongrES1 was isolated and cloned by screening rat epididymis cDNA libraryusing a mouse EST as a probe and 5‘RACE followed. It contained 1590bp nucleotides and its predictedprotein had 415 amino acid residues including a serpin (serine protease inhibitor) conserved domain. Tissuedistribution pattern showed it was specifically expressed in adult rat epididymis; moreover, in situ hybridyza-tion indicated this gene was expressed in a limited region of the cauda epididymis near vas deference. Suchkind of expression pattern sugested that HongrES1 had potential function in male reproduction.     

刺激猫下丘脑LHA和VMN对小脑皮层神经元电活动的影响

在戊巴比妥钠麻醉的猫,电刺激下丘脑外侧区(LHA)和腹内侧核(VMN)可引起小脑皮层第Ⅵ和Ⅶ小叶浦肯野细胞和非浦肯野细胞抑制性、兴奋性和抑制-兴奋性的电活动,但以抑制性活动为主;这些反应的潜伏期多数为10-20ms,但也可长达90ms;一般刺激LHA比刺激VMN更有效。刺激下丘脑所激发的小脑神经元抑制性电活动可为静脉注射组胺H_1受体阻断剂扑尔敏所阻断。本文对上述观察的可能作用作了讨论。     

Cryptic diversity in the pen shell Atrina pectinata (Bivalvia: Pinnidae): high divergence and hybridization revealed by molecular and morphological data

Cryptic species have been increasingly revealed in the marine realm through an analytical approach incorporating multiple lines of evidence (e.g., mtDNA, nuclear genes and morphology). Illustrations of cryptic taxa improve our understanding of species diversity and evolutionary histories within marine animals. The pen shell Atrina pectinata is known to exhibit extensive morphological variations that may harbour cryptic diversity. In this study, we investigated A. pectinata populations along the coast of China and one from Japan to explore possible cryptic diversity and hybridization using a combination of mitochondrial (cytochrome c oxidase subunit I, mtCOI) and nuclear (ribosomal internal transcribed spacer, nrITS) genes as well as morphology. Phylogenetic analyses of mtCOI ‘DNA barcoding gene’ sequences resolved six divergent lineages with intralineage divergences between 0.4% and 0.8%. Interlineage sequence differences ranged from 4.3% to 22.0%, suggesting that six candidate cryptic species are present. The nrITS gene revealed five deep lineages with Kimura 2‐parameter distances of 3.7–30.3%. The five nuclear lineages generally corresponded to mtCOI lineages 1–4 and (5 + 6), suggestive of five distinct evolutionary lineages. Multiple nrITS sequences of significant variance were found within an individual, clearly implying recent hybridization events between/among the evolutionary lineages, which contributed to cytonuclear discordance. Morphologically, five morphotypes matched the five genetic lineages, although the intermediates may well blur the boundaries of different morphotypes. This study demonstrates the importance of combining multiple lines of evidence to explore species cryptic diversity and past evolutionary histories.     

Twelve polymorphic microsatellite loci for the South China tiger Panthera tigris amoyensis

Twelve microsatellite loci were found from genomic DNA‐enriched libraries of the South China tiger (Panthera tigris amoyensis). The number of observed alleles for each locus in 53 individuals ranged from five to 14; the expected and observed heterozygosity was 0.480 to 0.883 and 0.333 to 0.956, respectively; and the mean polymorphic information content (PIC) was 0.729. These markers would be considered a useful tool for the study of genetic variation in South China tiger in the future.     

交感传出对多觉型伤害性感受器持续放电的易化效应

向大鼠皮肤感受野注射复合致痛剂使多觉型伤害性感受器产生持续放电。刺激支配感受野的交感神经可使单位持续放电显著增多,部分单位为先易化后抑制。这种易化效应时程较长,可以反复激发。局部动脉注射去甲肾上腺素(5μg/0.2ml)也可引起类似的效应。结果证实交感神经传出活动能够易化多觉型伤害性感受器的持续放电。讨论了不同实验结果和产生烧灼痛的可能原因。     

The Ordovician Biodiversification: revolution in the oceanic trophic chain

The Early Palaeozoic phytoplankton (acritarch) radiation paralleled a long-term increase in sea level between the Early Cambrian and the Late Ordovician. In the Late Cambrian, after the SPICE δ¹³C_carb excursion, acritarchs underwent a major change in morphological disparity and their taxonomical diversity increased to reach highest values during the Middle Ordovician (Darriwilian). This highest phytoplankton diversity of the Palaeozoic was possibly the result of palaeogeography (greatest continental dispersal) and major orogenic and volcanic activity, which provided maximum ecospace and large amounts of nutrients. With its warm climate and high atmospheric CO₂ levels, the Ordovician was similar to the Cretaceous: a period when phytoplankton diversity was at its maximum during the Mesozoic. With increased phytoplankton availability in the Late Cambrian and Ordovician a radiation of zooplanktonic organisms took place at the same time as a major diversification of suspension feeders. In addition, planktotrophy originated in invertebrate larvae during the Late Cambrian–Early Ordovician. These important changes in the trophic chain can be considered as a major palaeoecological revolution (part of the rise of the Palaeozoic Evolutionary Fauna of Sepkoski). There is now sufficient evidence that this trophic chain revolution was related to the diversification of the phytoplankton, of which the organic-walled fraction is partly preserved.