Comparative studies of leaf surface chemical biosynthesis in different tobacco cultivars

To understand the differences in the biosynthesis of leaf surface chemicals and their influence on aphid preference for different tobacco cultivars (Nicotiana tabacum), we analyzed the secretory characteristics of glandular trichomes of four commercial cultivars, K326 (flue-cured), Beinhart 1000-1 (cigar), Basma YNOTBS1 (oriental), and Dabai 1 (burley), and their parental species, Nicotiana sylvestris and Nicotiana tomentosiformis. Trichome-type observation showed that K326 and N. sylvestris have three kinds of glandular trichomes (non-glandular, long stalked glandular, and short stalked glandular trichomes), whereas Beinhart 1000-1, Basma YNOTBS1, Dabai 1, and N. tomentosiformis had two kinds of glandular trichomes (long and short stalked glandular trichomes). The gas chromatography–mass spectrometry profiles of leaf exudates indicated that N. tomentosiformis synthesized only labdanoids; N. sylvestris, K326 and Dabai 1 synthesized only cembranoids; and Beinhart 1000-1 and Basma YNOTBS1 synthesized cembranoids and labdanoids. Gene expression pattern analysis revealed that the labdanoid synthesis-related genes NtABS and NtCPS2 were expressed in N. tomentosiformis, Beinhart 1000-1, and Basma YNOTBS1, whereas the cembranoid synthesis-related genes NtCYC and NtCYP71D16 were expressed in N. sylvestris and all four commercial cultivars. Evolutionary analysis indicated that NtCYC and NtCYP71D16 might be phylogenetically originated from N. sylvestris, whereas NtABS and NtCPS2 expressed in Basma YNOTBS1 and Beinhart 1000-1 might be derived from N. tomentosiformis. In addition, aphid attraction (number of aphids) was significantly and positively correlated with the total glandular secretion (r² =?0.9425, P?≤?0.05), and it was significantly and positively correlated with amount of CBT-diol (r²?=?0.9224; P?≤?0.05). These results provide new insights into the biosynthesis of diterpenoids and biotic stress resistance in tobacco.     

<Emphasis Type="Italic">R</Emphasis>-acetoin accumulation and dissimilation in <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis>

Klebsiella pneumoniae is a 2,3-butanediol producer, and R-acetoin is an intermediate of 2,3-butanediol production. R-acetoin accumulation and dissimilation in K. pneumoniae was studied here. A budC mutant, which has lost 2,3-butanediol dehydrogenase activity, accumulated high levels of R-acetoin in culture broth. However, after glucose was exhausted, the accumulated R-acetoin could be reused by the cells as a carbon source. Acetoin dehydrogenase enzyme system, encoded by acoABCD, was responsible for R-acetoin dissimilation. acoABCD mutants lost the ability to grow on acetoin as the sole carbon source, and the acetoin accumulated could not be dissimilated. However, in the presence of another carbon source, the acetoin accumulated in broth of acoABCD mutants was converted to 2,3-butanediol. Parameters of R-acetoin production by budC mutants were optimized in batch culture. Aerobic culture and mildly acidic conditions (pH 6–6.5) favored R-acetoin accumulation. At the optimized conditions, in fed-batch fermentation, 62.3 g/L R-acetoin was produced by budC and acoABCD double mutant in 57 h culture, with an optical purity of 98.0 %, and a substrate conversion ratio of 28.7 %.     

Recognition of Cytosolic DNA Attenuates Glucose Metabolism and Induces AMPK Mediated Energy Stress Response

Both viral infection and DNA transfection expose single-stranded or double-stranded DNA to the cytoplasm of mammalian cells. Recognition of cytosolic DNA activates a series of cellular responses, including induction of pro-inflammatory genes such as type I interferon through the well-known cGAS-STING pathway. Here we show for the first time that intracellular administration of either single or double stranded interferon stimulating DNA (ISD), but not poly(dA) suppresses cell growth in many different cell types. Suppression of cell growth by cytosolic DNA is cGAS/STING independent and associated with inhibition of glucose metabolism, ATP depletion and subsequent cellular energy stress responses including activation of AMPK and inactivation of mTORC1. Our results suggest that in concert with but independent of innate immune response, recognition of cytosolic DNA induced cellular energy stress potentially functions as a metabolic barrier to viral replication.     

天南星科植物的花多样性与传粉策略

天南星科植物具有特殊的佛焰苞花序及多样化的传粉策略, 是研究被子植物花的分化与动植物之间进化生态学联系的理想材料。本文简述了天南星科不同类型的花序结构及其传粉适应意义, 总结了天南星科传粉策略的基本类型与演化历史。天南星科的苞片结构主要包括原始型、外展平面型、直立宽佛焰苞型和直立狭佛焰苞4种类型, 呈现出从简单的片状与外展平面状结构向复杂的立体包裹状的佛焰苞结构演化的趋势。肉穗花序可分为两性花花序、单性花雌雄同序和单性花雌雄异序3种类型, 演化路线为两性花花序→单性花雌雄同序→单性花雌雄异序。天南星科的传粉者主要有鞘翅目、双翅目、膜翅目昆虫, 表现出5种主要传粉策略: 食物报酬型互利传粉、气味吸引型欺骗性传粉、交配场所型互利传粉、产卵场所型互利传粉和致死陷阱型欺骗性传粉。天南星科植物通过花序的形状、颜色、产热以及花部挥发物来吸引传粉者, 其中最主要的挥发物有二甲基硫化物、甲基吲哚化合物、萜类和苯类化合物, 模拟食物或产卵场所信号吸引鞘翅目甲虫和双翅目昆虫为其传粉。天南星科植物的佛焰苞被认为是促进该科物种分化的一个重要结构, 但该性状的演化历史及其与传粉系统分化之间的内在联系尚不明确。利用现代分子生物学技术以及模型模拟等手段, 结合生理生态学方法深入探究传粉事件与天南星科植物的花多样性以及物种分化之间的联系, 有望提升关于植物-传粉者互作与植物的花多样性分化之间关系的认识, 并丰富对被子植物多样性演化相关研究的理解。     

Spatio-Temporal Analysis of the Accuracy of Tropical Multisatellite Precipitation Analysis 3B42 Precipitation Data in Mid-High Latitudes of China

Satellite-based precipitation data have contributed greatly to quantitatively forecasting precipitation, and provides a potential alternative source for precipitation data allowing researchers to better understand patterns of precipitation over ungauged basins. However, the absence of calibration satellite data creates considerable uncertainties for The Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) 3B42 product over high latitude areas beyond the TRMM satellites latitude band (38°NS). This study attempts to statistically assess TMPA V7 data over the region beyond 40°NS using data obtained from numerous weather stations in 1998–2012. Comparative analysis at three timescales (daily, monthly and annual scale) indicates that adoption of a monthly adjustment significantly improved correlation at a larger timescale increasing from 0.63 to 0.95; TMPA data always exhibits a slight overestimation that is most serious at a daily scale (the absolute bias is 103.54%). Moreover, the performance of TMPA data varies across all seasons. Generally, TMPA data performs best in summer, but worst in winter, which is likely to be associated with the effects of snow/ice-covered surfaces and shortcomings of precipitation retrieval algorithms. Temporal and spatial analysis of accuracy indices suggest that the performance of TMPA data has gradually improved and has benefited from upgrades; the data are more reliable in humid areas than in arid regions. Special attention should be paid to its application in arid areas and in winter with poor scores of accuracy indices. Also, it is clear that the calibration can significantly improve precipitation estimates, the overestimation by TMPA in TRMM-covered area is about a third as much as that in no-TRMM area for monthly and annual precipitation. The systematic evaluation of TMPA over mid-high latitudes provides a broader understanding of satellite-based precipitation estimates, and these data are important for the rational application of TMPA methods in climatic and hydrological research.     

绵羊的卷唇行为及其生物学意义

本文研究了绵羊对不同品种公母羊的尿液、母羊粪便、阴道分泌物、身体的气味等刺激物诱导卷唇行为的发生,持续约60-120秒。实验得出:母羊尿液是诱导公羊释放卷唇行为最强的刺激物,尤以发情母羊尿液更甚,公羊、幼羊以及其它的尿液诱导卷唇行为发生的频次低。卷唇行为发生的频次有季节变化,10月最高。卷唇行为与犁鼻器的功能紧密联系,是绵羊繁殖行为的一个构成部分,通常只有公羊发生卷唇行为,但个别母羊亦有表现。     

Nasal delivery of broadly neutralizing antibodies protects mice from lethal challenge with SARS-CoV-2 delta and omicron variants

Multiple new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have constantly emerged, as the delta and omicron variants, which have developed resistance to currently gained neutralizing antibodies. This highlights a critical need to discover new therapeutic agents to overcome the variants mutations. Despite the availability of vaccines against coronavirus disease 2019 (COVID-19), the use of broadly neutralizing antibodies has been considered as an alternative way for the prevention or treatment of SARS-CoV-2 variants infection. Here, we show that the nasal delivery of two previously characterized broadly neutralizing antibodies (F61 and H121) protected K18-hACE2 mice against lethal challenge with SARS-CoV-2 variants. The broadly protective efficacy of the F61 or F61/F121 cocktail antibodies was evaluated by lethal challenge with the wild strain (WIV04) and multiple variants, including beta (B.1.351), delta (B.1.617.2), and omicron (B.1.1.529) at 200 or 1000 TCID50, and the minimum antibody administration doses (5-1.25 mg/kg body weight) were also evaluated with delta and omicron challenge. Fully prophylactic protections were found in all challenged groups with both F61 and F61/H121 combination at the administration dose of 20 mg/kg body weight, and corresponding mice lung viral RNA showed negative, with almost all alveolar septa and cavities remaining normal. Furthermore, low-dose antibody treatment induced significant prophylactic protection against lethal challenge with delta and omicron variants, whereas the F61/H121 combination showed excellent results against omicron infection. Our findings indicated the potential use of broadly neutralizing monoclonal antibodies as prophylactic and therapeutic agent for protection of current emerged SARS-CoV-2 variants infection.     

混合氨基酸月桂酰胺的合成

本文以玉米淀粉生产副产物为原料,提取蛋白质水解制取混合氨基酸,与酰化剂月桂酰氯合成混合氨基酸月桂酰胺表面活性剂,研究了反应条件,并测定了它的pH值、表面张力、乳化力等。     

用FT—IR技术研究人卵泡促性腺激素释放肽hF—GRP及其类似物TF14的二级结构

用付立叶变换红外（ＦＴ—ＩＲ）技术,定量分析了人卵泡促性腺激素释放肽ｈＦ—ＧＲＰ及其类似物ＴＦ１４这两个多肽在重水溶液中的二级结构,结果为ｈＦ－ＧＲＰ有近四分之一的残基处于无规卷曲,其余部分是非典型的伸展结构,ＴＦ１４则基本上处于伸展和转角结构,无规和螺旋的成分很少,这与用二维核磁共振技术测定的ｈＦ—ＧＲＰ和ＴＦ１４的溶液构象实验结果非常吻合。     

林带横断面几何形状与阻力关系的实验研究

林带横断面几何形状与阻力关系的实验研究关德新,王述礼,朱廷曜（中国科学院沈阳应用生态研究所１１００１５）ＥｘｐｅｒｉｍｅｎｔａｌＳｔｕｄｙｏｎｔｈｅＲｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎＳｅｃｔｉｏｎＦｏｒｍｏｒＳｈｅｌｔｅｒｂｅｌｔａｎｄＩｔｓＷｉ...