Host-Parasite Interactions and Purifying Selection in a Microsporidian Parasite of Honey Bees

To clarify the mechanisms of Nosema ceranae parasitism, we deep-sequenced both honey bee host and parasite mRNAs throughout a complete 6-day infection cycle. By time-series analysis, 1122 parasite genes were significantly differently expressed during the reproduction cycle, clustering into 4 expression patterns. We found reactive mitochondrial oxygen species modulator 1 of the host to be significantly down regulated during the entire infection period. Our data support the hypothesis that apoptosis of honey bee cells was suppressed during infection. We further analyzed genome-wide genetic diversity of this parasite by comparing samples collected from the same site in 2007 and 2013. The number of SNP positions per gene and the proportion of non-synonymous substitutions per gene were significantly reduced over this time period, suggesting purifying selection on the parasite genome and supporting the hypothesis that a subset of N. ceranae strains might be dominating infection.     

Oat leaf base: tissue with an efficient regeneration capacity

Summary An efficient short term regeneration system using seedling derived oat (Avena sativa) leaf tissue has been developed. Callus derived from the leaf base showed a higher response of plant regeneration than callus initiated from mesocotyls and more mature parts of the leaves. A correlation between the nuclear DNA content of the donor material, as analysed with flow cytometry, and its ability to form callus was observed. Somatic embryogenesis was histologically recognised from callus derived from tissue close to the apical meristem. Plant regeneration media with various concentrations of auxin were tested. Callus from three different cultivars had a similar regeneration potential with an optimal regeneration frequency of 60%. About 2 months after inoculation regenerated plantlets could be moved to a greenhouse for cultivation.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - DAPI 6-diamidino-2-phenylindole - IAA indole-3-acetic acid - KT kinetin - MS Murashige and Skoog's medium - NAA naphthalene acetic acid     

云南栉眼蚤属一新种：蚤目：多毛蚤科

本文记述了从滇西北边陲担打力卡山脉采获的栉眼蚤属一新种——解氏栉眼蚤Ctenophthalmus(Sinoctenophthalmux)xiei。本新种与端凹栉眼蚤Ctenophthalmus(S.)parcus Jordan,1932近缘,但可根据其下唇须,可动突、第九腹板和阳茎端侧叶以及第七腹板后缘的形态等特征与后者区分。     

小麦幼苗根系镉螯合素

从经Cd~(2+)处理的小麦幼苗根系中分离得到一种镉结合复合物(Cd-BC)。通过SephadexG75,DEAE-52柱层析纯化,鉴定了此复合物性质:(1)紫外吸收光谱在255～265 tim间有一个“肩”,A_(250)/A_(280)>1;(2)在Sephadex G75柱层析上的表观分子量约为10kD,但在SDS-聚丙烯酰胺凝胶电泳上呈现的条带紧接着前沿,分子量非常小;(3)氨基酸组分分析,约90％的氨基酸残基为Glu/Gln,Cys和Gly,三者比例约为4:4:1。结果说明小麦幼苗根系Cd-BC是寡聚肽,是植物镉螯合素(Cd-PCs)的聚合体。     

氧自由基对大鼠心肌α1肾上腺素受体及其亚型的影响

采用放射配体结合方法观察外源性氧自由基对大鼠心肌α_１肾上腺素受体（α_１受体）及其亚型α_（１Ａ）与α_（１Ｂ）的影响和对β肾上腺素受体（β受体）的影响。发现：（１）·ＯＨ,使α_１受体与~（１２５）ＩＢＥ２２５４最大结合量（Ｂ_（ｍａｘ））分别下降５５％与３６％。（２）·ＯＨ可使α_１受体与~（１２５）ＩＢＥ２２５４结合的Ｋ_ｄ值增高１７１％,而对Ｋ_ｄ值无影响。（３）·ＯＨ,均使α_１受体亚型α_（１Ａ）与α_（１Ｂ）之间的比例增加。（４）·ＯＨ,对β受体与~（１２５）ＩＰＩＮ最大结合量Ｂ_（ｍａｘ）和Ｋ_ｄ值均无影响。（５）氧自由基清除剂甘露醇或超氧化物歧化酶均可对抗氧自由基引起α_１受体及其亚型的改变。上述结果提示,氧自由基可直接作用于心肌膜,引起α_１受体数量和亲和性下降,α_１受体亚型α_（１Ａ）与α_（１Ｂ）之间的比例改变。     

肝再生的调控及原癌基因表达

肝脏再生过程中受到多种体液因素的调控。肝细胞生长因子（ＨＧＦ）、肝刺激因子（ＨＳＳ）等对肝细胞有促分裂作用;转化生长因子β１（ＴＧＦβ１）等则具有抑制作用。此外,肝再生还需要去甲肾上腺素（ＮＥ）、胰岛素等辅助分裂原的存在,共同调节肝再生。肝细胞分裂增殖与原癌基因表达密切相关。肝细胞从静息期进入细胞周期,以及在整个细胞周期中,某些原癌基因有特征性的表达。