The complete mitochondrial genome of the mackerel icefish,Champsocephalus gunnari (Actinopterygii: Channichthyidae), with reference to the evolution of mitochondrial genomes in Antarctic notothenioids

The mackerel icefish (Champsocephalus gunnari Lönnberg, 1905) is a ray‐finned fish living in the Southern Ocean around Antarctica. We sequenced the complete mitochondrial (mt) genome of the mackerel icefish and a segment from cytochrome b to the control region (CR) in 32 individuals. The mt genome of the mackerel icefish was rearranged, containing two nicotinamide adenine dinucleotide (reduced form) dehydrogenase subunit 6 (ND6), two tRNA^Glu, and two CRs. However, variations in numbers of ND6 and tRNA^Glu were observed amongst individuals. These variations included type 1 (containing two ND6 and two tRNA^Glu), type 2 (containing one ND6, one incomplete ND6, and one tRNA^Glu), and type 3 (containing one ND6 and one tRNA^Glu). The gene orders of types 1 and 2, and variations in numbers of ND6 and tRNA^Glu were not previously found in any Antarctic notothenioids, whereas type 3 is the same as that of Racovitzia glacialis. Phylogenetic analyses of CR DNA sequences showed that duplicated CRs of the same species formed a monophyletic group, suggesting that duplication of CRs occurred in each species. The frequent duplication of mt genomes in Antarctic notothenioids is an unusual feature in vertebrates. We propose that interspecific hybridization and impairment of mismatch repair might account for the high frequency of gene duplications and rearrangement of mt genomes in Antarctic notothenioids.     

Effects of Chemicals Often Regarded as Germination Stimulants on Seed Conditioning and Germination of Witchweed (Striga asiatica)

Gibberellin A₃ (GA₃), kinetin and zeatin promoted germinationof conditioned witchweed (Striga asiatica [L.] Kuntze) seedssimilar to dl-strigol and a natural stimulant from corn rootexudates. GA₃ promoted germination only with scarified seeds.However, these regulators, as well as dl-strigol and naturalstimulants, inhibited the conditioning of seeds and their subsequentgermination. On the other hand, abscisic acid induced 74% germinationof conditioned seeds but had no effect on seed conditioning.Other chemicals such as sucrose, NaNO₃, vitamin B₁, L-methionine,nicotinamide, indoleacetic acid and colchicine had no apparenteffect on seed conditioning, while sucrose, L-methionine andinositol induced about 30 % germination of conditioned seeds.Seeds generally required either a longer conditioning time ora higher terminal dl-strigol concentration to eliminate anyinhibition of seed conditioning induced by a compound. dl-Strigol, germination stimulation, parasitic plants, seed conditioning, seed germination, Striga asiatica (L.) Kuntze, weed control, growth regulating substances     

中国猎蝽亚科简记(半翅目:猎蝽科)

猎蝽亚科(Reduviinae)是猎蝽科中的一个较大的亚科。各属的外形颇不一致,其共同的特征是:前翅无中室,小盾片端部具刺或瘤状突起,有时侧缘基部具刺。头长,前端向下倾斜或弯曲,具横缢及单眼。膜片内室伸向外室基部的前方,前胸背板横缢约位于背板中央。 本亚科的种类广泛分布于世界各地区,现在我国共发现16属42种,其中有14个新种,有8个属和10个种是我国的首次纪录,另外还有两个新同物异名。本文着重记述了     

中国猎蝽科的新种和新纪录Ⅱ

本文记述了在我国发现的猎蝽六种,包括四个新种和两个在我国的首次纪录。其中属于毛猎蝽亚科(Holoptilinae)一种,飒猎蝽亚科(salyavatinae)四种及新猎蝽亚科(Centrocneminae)一种。还讨论了这几个亚科和盗猎蝽亚科(Piratinae)在我国所记载的种类,并附以属种的检索表。 毛猎蝽亚科Holoptilinae 这是一个较小的亚科,在我国福建曾记载一属一种:Holoptilus viverra(Walk.);现在广西南宁又发现一个新种,记述如下: Holoptilus silvanus新种(图1)     

中国瘤蝽科的新种和新纪录(半翅目:异翅亚目)

本文记述了我国的瘤蝽5属8种,其中包括6个新种及国内首次纪录的2个属和2个种。     

Seasonal Changes in Water Potential and Turgor Maintenance in Sorghum and Maize under Water Stress

Leaf water (Ψ) and solute (ψ) potential were measured in field sorghum and maize under well irrigated (I) and dryland (NI) conditions throughout a season. Despite decreases in ψ due to slow soil water depletion and to apparent increases in liquid phase plant resistance, midday leaf turgor (ψ_p) in the NI sorghum was maintained at similar levels as in the I treatment throughout the season due to concomitant decreases in ψ_s. Osmotic adjustment was also observed in maize, although ψ_p was significantly lower in the NI treatment as compared to I during the final stages of grain filling. A seasonal shift in the ψ vs. relative water content relation of NI sorghum leaves was observed, more water being retained by the older leaf at any particular ψ. The major factor for turgor maintenance was a net increase in solutes per unit of tissue. The role played by increases in the proportion of tissue volume occupied by cell wall was also evaluated. No stomatal closure due to water stress was found in NI sorghum even though leaf ψ reached —20 bars late in the season. Under similar conditions, stomata closed at —14 to —16 bars in younger plants where water stress was made to develop much faster.     

中国的麦蝽属记述(半翅目:蝽科)

麦蝽(Aclia)为我国北方较常见的一类蝽科昆虫,生活于禾本科植物上,有的种类成为麦类的害虫,所以国内许多昆虫学资料上常称之为“麦蝽象”。本属体菱形,头大,三角形,侧叶远伸出于中叶之前,并相互靠紧,颊延向头下方并成片状下垂,在小颊前占据很大位置,前胸侧板前缘翘起。特征显著,易于辨认。     

云南生物考察报告(半翅目:红蝽科及大红蝽科)

1955—1957年间在云南各地进行动植物调查,收集了大量的昆虫标本。本篇是关于半翅目红蝽科及大红蝽科标本的鉴定报告。共计13属24种,其中包括一个新属4个新种。除新属新种外,有4个属和8个种是中国的首次记录(以＊符号标记)。新种的种模标本和配模标本都由中国科学院动物研究所保存。     

用改进的差别显示法克隆R6大鼠细胞的癌相关基因

为了识别参与细胞癌变的基因,本文选择p53135-val-过表达正常细胞系R6#13-8及其自发转化癌变细胞系T2作为研究材料,在克隆差异表达基因的同时,建立了一种简单、快速的差异表达基因分离的方法,并已克隆到2个与细胞癌变相关的候选新基因。本文所得的实验结果表明这种方法实验步骤简单,避免使用同位素,RT-PCR扩增带的重复性好,能克隆到大于500bp的差异表达cDNA片段,差异表达的PCRcDNA片段假阳性率低,并可广泛适用于在两个或两个以上相对应真核细胞RNA群体中分离和克隆特异表达基因。研究结果还提示在R6#13-8自发转化为T2的过程中涉及多个基因的激活与失活,这两个细胞系之间存在明显的基因表达差异。     

Can overexpression of TGF—β1 gene change the sex ratio in transgenic mice？

Mouse TGF-β1 gene was microinjected into male pronuclei of F2 hybrid fertilized eggs obtained by mating CSJLF1 and C57BL/6J inbred strains to generate transgenic mice with over-expressed TGF-β1 gene.The rate of founder production is 31% and Southern blot analysis of founder mice tail DNAs gave an integration efficiency of 33%.TGF-β1 gene could be stably integrated to the chromosomes of transgenic mice and transmitted to their progeny at a rate of 33% in the second generation.Dot blot analysis of tail RNA of some transgenic mice indicated a moderate expression of the transgene.The most interestin finding of the present work is the striking eviation from the normal male:female sex ratio in transgenic mice,with an average ratio of 6.7:1.The possible nature of the predominance of male sex in transgenic mice overexpressing TGF-β1 is discussed.