Cloning and sequencing of cDNAs for hypothetical genes from chromosome 2 of Arabidopsis

About 25% of the genes in the fully sequenced and annotated Arabidopsis genome have structures that are predicted solely by computer algorithms with no support from either nucleic acid or protein homologs from other species or expressed sequence matches from Arabidopsis. These are referred to as "hypothetical genes." On chromosome 2, sequenced by The Institute for Genomic Research, there are approximately 800 hypothetical genes among a total of approximately 4,100 genes. To test their expression under various growth conditions and in specific tissues, we used six cDNA populations prepared from cold-treated, heat-treated, and pathogen (Xanthomonas campestris pv campestris)-infected plants, callus, roots, and young seedlings. To date, 169 hypothetical genes were tested, and 138 of them are found to be expressed in one or more of the six cDNA populations. By sequencing multiple clones from each 5'- and 3'-rapid amplification of cDNA ends (RACE) product and assembling the sequences, we generated full-length sequences for 16 of these genes. For 14 genes, there was one full-length assembly that precisely supported the intron-exon boundaries of their gene predictions, adding only 5'- and 3'-untranslated region sequences. However, for three of these genes, the other assemblies represent additional exons and alternatively spliced or unspliced introns. For the remaining two genes, the cDNA sequences reveal major differences with predicted gene structures. In addition, a total of six genes displayed more than one polyadenylation site. These data will be used to update gene models in The Institute for Genomic Research annotation database ATH1.     

BALB／C小鼠的白内障突变与大片段小卫星DNA多态性的变化

为了探讨ＢＡＬＢ／Ｃ小鼠白内障突变品系与ＢＡＬＢ／Ｃ小鼠保种品系二者间小卫星ＤＮＡ多态性的变化,为进一步研究变异小卫星位点与白内障突变基因的关系最终找到导致这种白内障形成的基因奠定基础,采用α－＾３２Ｐ－ｄＣＴＰ标记的人类小卫星ＤＮＡ探针Ｍｙｏ,通过Ｓｏｕｔｈｅｒｎ杂交比较了正常ＢＡＬＢ／Ｃ和ＢＡＬＢ／Ｃ白内障突变体小卫星ＤＮＡ多态性的变化。结果：ＢＡＬＢ／Ｃ白内障小鼠种内ＤＮＡ多态性带纹分布高度     

Changes of characteristics of preoptic neurons and NA metabolism in hypothalamus of ground squirrel (Citelleus Dautieus) in different seasons and hibernating phases

The unit firing activities of neurons in the preoptic area (POA) of ground squirrel hypothalamic tissue slices were recorded and the metabolism of NA in hypothalamus was measured with high performance liquid chromatography (HPLC). Thermosensitivity, proportions, the critical temperature (Tc) and the lowest temperature (TL) of firing activity of the above-mentioned neurons, and NA metabolism in hypothalamus were compared in different seasons and hibernating phases. In comparison with that in summer euthermar, it was shown that (i) the percentage and thermosensitivity of the POA neurons varied respectively in the hibernating phases; (ii) TL and Tc of the POA neurons in winter, both euthermar and hibernation, were markedly decreased; (iii) the POA neurons in hibernation became much more sensitive to NA, and the response of cold-sensitive neurons to NA changed from inhibiting pattern in summer to exciting one in hibernation; (iv) the contents and metabolism of NA in hypothalamus decreased significantly in the entering phase and deep hibernation phase, while the metabolism of NA increased remarkably in the arousal phase. These changes might explain the regulatory mechanism how ground squirrel actively decreases body temperature (Tb) in entering into hibernation and quickly recovers body temperature in arousal phase. Project supported by the National Natural Science Foundation of China (Grant Nos. 39230060 and 39570100)     

Changes of characteristics of preoptic neurons and NA metabolism in hypothalamus of ground squirrel (Citelleus Dautieus) in different seasons and hibernating phases

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人乳铁蛋白基因在昆虫细胞中的表达

将人乳铁蛋白ｃＤＮＡ（ｈＬＦｃ）克隆在质粒ｐＢａｃＰＡＫ８的ＢａｍＨＩ和ＳａｃＩ位点,构建成转移质粒８ｈＬＦｃ。该质粒ＤＮＡ与ＡｃＮＰＶ ＢａｃＰＡＫ６病毒株基因组ＤＮＡ经共转染草地夜峨培养细胞Ｓｆ２１,在培养的贴壁细胞中挑出空斑,经过３轮纯化,结合斑点杂交筛选,获得重组病毒。用蛋白质免疫印迹法检测到在重组病毒感染的Ｓｆ－２１细胞中存在乳铁蛋白基因的表达产物。酶联免疫检测结果表明：重组人乳铁蛋白在     

半理性设计进化土曲霉来源的ω-转氨酶AtTA热稳定性

转氨酶(ω-transaminase,ω-TA)作为一种天然的生物催化剂,在手性胺类化合物的合成中具有较好的应用前景。但ω-TA在催化非天然底物的反应过程中存在稳定性差、活性低的缺陷,大大限制了ω-TA的应用。为改善此缺陷,针对来源于土曲霉(Aspergillus terreus)的(R)-ω-TA(At TA),采用基于分子动力学模拟的计算机辅助设计与随机突变、组合突变相结合的策略进行酶的热稳定性改造,获得了热稳定性与活性同步提高的最佳突变酶At TA-E104D/A246V/R266Q (M3)。与At TA野生酶(wild-type, WT)相比,M3的半衰期t_1/2 (35℃)由17.8 min提升至102.7 min,提升了4.8倍,半失活温度T₅₀¹⁰比WT (38.1℃)提高2.2℃。最佳突变酶M3对丙酮酸和1-(R)-苯乙胺的催化效率分别是野生酶的1.59倍和1.56倍。分子动力学模拟与分子对接结果表明,分子内氢键与疏水相互作用的增加所导致α-螺旋的加固稳定是酶热稳定性提升的主要原因;底物分子与结合口袋氨...     

青海岩羊源小反刍兽疫病毒N、F基因的遗传进化分析

2021年1月19日,青海省海西州都兰县巴隆乡伊克高里村发生岩羊不明原因的死亡,表现为离群独处、卧地不起、体质虚弱、觅食困难、肛门周围黑色附着物等现象。通过临床症状、病理学解剖及实时荧光RT-PCR诊断,为小反刍兽疫病毒(PPRV)感染。采用RT-PCR技术从病死岩羊病料组织中扩增出了PPRV N、F基因的部分片段。采用MegAlig、NT1和MEGA6.0软件对岩羊PPRV株N、F基因序列进行了比对和分析,绘制系统进化树,结果显示：此次岩羊感染的PPRV株N、F基因片段与新疆株(China/Xinjiang/2015/16)序列片段的同源性分别为99.43%和99.73%。遗传进化分析,该病原属于基因Ⅳ系。在N、F基因核酸序列水平上,与国内新疆地区分离毒株亲缘关系最近,同在一个小的分支;与国外毒株相比,N基因与塞内加尔和尼日利亚分离毒株亲缘关系较远,F基因与国外分离毒株亲缘关系较远。综上所述,青海岩羊源PPRV株属于基因Ⅳ系,与当前我国流行的野毒株属于同一个谱系。     

高原鼢鼠和甘肃鼢鼠胆汁无机元素含量分析

<正>无机元素在动物发育、免疫调节、代谢和繁殖等方面发挥着重要作用(刘季科等,1991;蒲俊华等,2010;Talebnejadetal.,2021;Gashkinaet al., 2022)。现代医学已证明,无机元素的种类和含量影响药材的药性和药效(谭文敏,2015;陈虹等,2017),其已逐渐成为动物药鉴别、炮制加工、质量评价和寻找替代品的重要依据(罗兴洪等,2004)。熊胆属于传统珍稀濒危动物药,     

大熊猫脐带间充质干细胞外泌体的分离鉴定及miRNAs富集分析

大熊猫脐带间充质干细胞(Umbilical cord mesenchymal stem cells, UC-MSCs)通过旁分泌所释放的外泌体在大熊猫保健与疾病治疗方面具有一定的应用前景。本研究旨在建立大熊猫UC-MSCs外泌体分离方法,开展生物学特征分析和分子鉴定,并研究UC-MSCs外泌体中miRNAs的种类与功能。采用超速离心法从大熊猫UCMSCs培养上清中成功分离外泌体,通过透射电子显微镜进行形态学观察,纳米颗粒跟踪分析仪检测粒径大小,蛋白免疫印迹法检测特异性分子标记表达。采用Small RNA测序技术对UC-MSCs外泌体中的miRNAs进行鉴定,并对其靶基因进行了预测与功能分析。结果显示,大熊猫UC-MSCs外泌体呈圆形杯托状结构,直径为(79.15±4.81) nm,外泌体标志蛋白CD81与TSG101呈阳性表达而CALNEXIN呈阴性表达。大熊猫UC-MSCs外泌体中的miRNA主要为miR-148-3p (30.28%)与miR-21-5p (21.72%)。本研究首次从大熊猫UC-MSCs培养上清中分离出外泌体,并对其所含的miRNAs进行富集分析及功能预测,为大熊...     

苯胺降解菌的筛选、降解特性及其发酵优化

【背景】近年来,苯胺类化合物加重了生态环境的污染,而生物法处理苯胺类废水具有较大发展潜力与广阔的应用前景。【目的】从长期受苯胺类化合物污染的活性污泥中分离获得一株能高效降解苯胺的菌株,优化其培养基及降解条件,为苯胺生物修复提供菌株与基因资源。【方法】采用平板法从富集驯化的菌株中筛选出以苯胺为唯一碳氮源和能源的高效降解菌,通过16S rRNA基因测序鉴定菌种,利用单因素筛选实验对降解条件进行优化,通过正交试验优化培养条件。【结果】筛选到一株苯胺降解菌BA-6,经鉴定为微杆菌属(Microbacterium)。菌株BA-6对初始浓度为600mg/L苯胺的日降解率可达98%以上。其高效降解的温度范围是30–37℃,pH范围是6.5–7.5。底物利用实验表明,菌株BA-6具有降解多种苯胺类化合物的能力。发酵培养基优化实验获得一种发酵培养基,活菌量高达3.06×10¹⁰CFU/mL。【结论】苯胺降解菌BA-6对苯胺有较强的降解能力和环境调节能力,在修复苯胺类化合物的生态污染方面有一定的应用前景。