长白猪、枫泾猪和它们的杂种后代Ag—NOR的研究

4头枫泾猪,3头长白猪和5头长白×枫泾杂一代的NOR平均数分别为3.88、2和2.95。33头长白×枫泾杂二代猪(杂一代互交后代),其中7头黑猪的NOR众数为4,平均数为3.85;9头白猪的NOR众数为2,平均数为2.25;14头白猪的NOR众数为3,平均数为2.86;3头花猪的NOR众数分别为4.3、3,平均数为3.65、3.00和3.08。根据长白、枫泾和长白×枫泾杂一代和杂二代的NOR数目的区别和变化,NOR的遗传符合孟德尔定律。根据NOR数目与毛色的高度相关,提出了决定猪的黑白毛色的基因位于8号染色体并与NOR连锁的假设。猪的毛色除由位于8号染色体上的毛色基因所决定外,还应受其它基因位点的影响。     

人熊冲突缓解措施研究进展——以三江源国家公园为例

人与熊科动物之间的冲突已成为亚洲、欧洲和美洲地区的一个普遍问题,科学有效的人熊冲突管控措施有助于人熊共存机制的建立。目前,全球范围内肇事熊科动物涉及7种,分别为棕熊、亚洲黑熊、美洲黑熊、北极熊、马来熊、懒熊和眼镜熊。肇事类型主要包括伤人、捕食牲畜、入侵房屋、损害庄稼、袭击蜂箱以及翻食垃圾。引发人熊冲突的原因与人类活动范围扩大、熊科动物种群数量上升、熊科动物生境质量下降、熊科动物自然食源周期性短缺、人类食物来源易获得性以及公众对肇事熊的容忍度下降有关。国际上已有的人熊冲突缓解措施包括物理措施、生物措施、化学措施以及政策导向性措施,然而,多数措施的制定仅停留在措施本身的技术层面上,缺乏对地方实际情况和冲突驱动因素的分析。西藏棕熊属于棕熊的一种稀有亚种,生活在靠近人类的中亚高海拔地区。在中国三江源国家公园地区,人类与西藏棕熊的冲突引起了人们的关注,为协助制订有效的保育目标、解决区内人熊冲突问题,提出以下缓解建议:(1)缓解措施的制定需因地而异,综合考虑地方实际情况,如地理环境、法律法规、民俗文化以及宗教信仰等;(2)冲突类型多样,防熊措施需持续更新与完善;(3)加强人类社会发展与熊科动物生存之间的关系研究,探索人们生产生活方式的改变与熊科动物行为变化之间的关系;(4)加强棕熊生态学方面的研究,从棕熊生境质量、种群动态、自然食源以及生态系统完整性等方面去深入挖掘人熊冲突的驱动因素,进而从根本上制定缓解措施,促进三江源国家公园地区人熊共存。     

我国禽流感研究进展及成就

禽流感不仅严重危害养禽业,而且给公共卫生造成巨大威胁。为了科学认识和积极防控禽流感,我国科学家进行了大量且富有成效的研究,取得了举世瞩目的成果。通过长期的监测,基本掌握了禽流感在我国的流行情况和进化规律;利用反向遗传操作技术和蛋白质组学技术,发现了影响流感病毒致病力、传播力和受体结合能力的部分关键位点,阐释了其作用机制;通过对传统技术的改进和先进方法的应用,不断成功建立禽流感诊断、检测技术;新型禽流感疫苗不断涌现并逐步被推广和应用,取得了良好的免疫效果。上述成果为我国禽流感的防控奠定了良好的基础,也为后续研究提供了依据。但是禽流感的防控形势依然严峻,2013年新型H7N9病毒的出现,使禽流感的防控面临新的挑战。     

SARS-CoV-2 envelope protein causes acute respiratory distress syndrome (ARDS)-like pathological damages and constitutes an antiviral target

Cytokine storm and multi-organ failure are the main causes of SARS-CoV-2-related death. However, the origin of excessive damages caused by SARS-CoV-2 remains largely unknown. Here we show that the SARS-CoV-2 envelope (2-E) protein alone is able to cause acute respiratory distress syndrome (ARDS)-like damages in vitro and in vivo. 2-E proteins were found to form a type of pH-sensitive cation channels in bilayer lipid membranes. As observed in SARS-CoV-2-infected cells, heterologous expression of 2-E channels induced rapid cell death in various susceptible cell types and robust secretion of cytokines and chemokines in macrophages. Intravenous administration of purified 2-E protein into mice caused ARDS-like pathological damages in lung and spleen. A dominant negative mutation lowering 2-E channel activity attenuated cell death and SARS-CoV-2 production. Newly identified channel inhibitors exhibited potent anti-SARS-CoV-2 activity and excellent cell protective activity in vitro and these activities were positively correlated with inhibition of 2-E channel. Importantly, prophylactic and therapeutic administration of the channel inhibitor effectively reduced both the viral load and secretion of inflammation cytokines in lungs of SARS-CoV-2-infected transgenic mice expressing human angiotensin-converting enzyme 2 (hACE-2). Our study supports that 2-E is a promising drug target against SARS-CoV-2.Subject terms: Cell death, Molecular biology     

TEB/POLQ plays dual roles in protecting Arabidopsis from NO-induced DNA damage

Nitric oxide (NO) is a key player in numerous physiological processes. Excessive NO induces DNA damage, but how plants respond to this damage remains unclear. We screened and identified an Arabidopsis NO hypersensitive mutant and found it to be allelic to TEBICHI/POLQ, encoding DNA polymerase θ. The teb mutant plants were preferentially sensitive to NO- and its derivative peroxynitrite-induced DNA damage and subsequent double-strand breaks (DSBs). Inactivation of TEB caused the accumulation of spontaneous DSBs largely attributed to endogenous NO and was synergistic to DSB repair pathway mutations with respect to growth. These effects were manifested in the presence of NO-inducing agents and relieved by NO scavengers. NO induced G2/M cell cycle arrest in the teb mutant, indicative of stalled replication forks. Genetic analyses indicate that Polθ is required for translesion DNA synthesis across NO-induced lesions, but not oxidation-induced lesions. Whole-genome sequencing revealed that Polθ bypasses NO-induced base adducts in an error-free manner and generates mutations characteristic of Polθ-mediated end joining. Our experimental data collectively suggests that Polθ plays dual roles in protecting plants from NO-induced DNA damage. Since Polθ is conserved in higher eukaryotes, mammalian Polθ may also be required for balancing NO physiological signaling and genotoxicity.     

冷型小麦对干旱和阴雨的双重适应性

通过 10余年的研究 ,发现冠层温度持续偏低的冷型小麦具有广幅生态适应性 ,即在正常天气条件下 ,它的活力较好、代谢功能较强、具有较好的抗早衰能力 ,优于其它类型小麦 ;而在气象要素反差很大的干旱和连阴雨天气下 ,冷型小麦和暖型小麦、中间型小麦相比 ,不但冠层温度依然持续偏低 ,且在叶片功能期、叶绿素含量、可溶性蛋白质含量、过氧化氢酶活性、净光合速率和籽粒饱满指数等一系列重要内、外性状上仍能继续保持优势。这种对干旱和阴雨条件的双重适应性是冷型小麦一种宝贵的生物学品质 ,它有可能为小麦在多种气象生态条件下的高产、稳产打下较为坚实的生态生理基础 ,并能为优良品种的选育提出一个把冷温特征作为重要内容的较为新鲜的育种目标。