ent-Pimarane Diterpenes from the Aerial Parts of Siegesbeckia pubescens

Five new ent-pimarane diterpenes ( 1 – 5 ) and five known analogs ( 6 – 10 ) were isolated from the aerial parts of Siegesbeckia pubescens. Their structures, including absolute configurations, were determined by comprehensive spectroscopic methods especially 1D and 2D NMR and quantum chemical electronic circular dichroism calculations. All the isolated compounds were evaluated for their cytotoxicity against human BT549, A549 and H157 cancer cell lines. Among them, compounds 1 and 2 showed mild cytotoxicity against lung cancer cell lines H157 with IC₅₀ values of 16.35±2.59 and 18.86±4.83 μM, respectively.     

Terpenoids from Euphorbia helioscopia and Their Cytotoxic Activities against H1975 Cells

Three previously undescribed diterpenoids, helioscopnoids A–C, and eight known compounds were isolated from the whole plants of Euphorbia helioscopia. Their structures were established by extensive analysis of spectra and data comparison with previous literatures. Among them, compound 4 was identified as 24,24-dimethoxy-25,26,27-trinoreuphan-3β-ol with revised configurations of C-13, C-14, and C-17 (13R*, 14R*, 17R*). Cytotoxicity assays revealed that all compounds exhibited varying levels of cytotoxicity against H1975 cells, with compound 9 displaying the most potent activity, as indicated by cell viability rates of 18.13 % and 20.76 % at concentrations of 20 μM and 5 μM, respectively. This study expands the understanding of E. helioscopia terpenoids’ structural diversity and biological activities, contributing to the exploration of potential therapeutic applications.     

Mitochondrial genome phylogeny reveals the deep-time origin of Gomphomastacinae (Orthoptera: Eumastacidae) and its alpine genera in China

Gomphomastacinae is a grasshopper subfamily in Eumastacidae, with a morphology and distribution distinct from other subfamilies. The alpine genera of Gomphomastacinae that inhabit the Qinghai–Tibet Plateau in China show unique characteristics adapted to high-altitude life. However, their phylogenetic position and biogeographic history remain controversial. Thus, to determine the diversification history of these alpine genera and the origin of the subfamily, we obtained mitochondrial genome sequences from all seven Gomphomastacinae genera distributed in China. The reconstructed phylogeny was well supported and confirmed the phylogenetic position of Gomphomastacinae within Eumastacidae. Time calibration revealed a deep-time origin of the subfamily dating back to the Cretaceous period, and the diversification among alpine genera was also an ancient pre-Miocene event (30–50 Ma). Based on phylogeny and time estimates, the most likely biogeographic scenario is that Gomphomastacinae originated from an ancestral lineage that lived in East Gondwana and dispersed to Central and Western Asia through India. Subsequently, the alpine genera likely diverged along with the uplift of the Qinghai–Tibet Plateau and survived drastic climate change by in situ adaptation to high-altitude dwellings.     

Collections-based systematics in the new age of discovery: Celebrating the legacy and life of Professor Wen-Tsai Wang

Professor Wen-Tsai Wang (王文采, June 5, 1926–November 16, 2022) was an academician of the Chinese Academy of Sciences (CAS) and a legendary plant taxonomist at the Institute of Botany of CAS (Fig.1). Herein, we organize a virtual special issue in Journal of Systematics and Evolution (JSE) to celebrate the legacy and life of Professor Wang, who was a leading plant taxonomist in China and made important contributions toward advancing the understanding of the flora of China, the biogeography of eastern Asia, and biodiversity research in the vast Hengduan Mountains. He served as the Editor-in-Chief of Acta Phytotaxonomica Sinica (now JSE) for 6 years from 1982 to 1988, and trained several generations of plant taxonomists in China (Li,2001).     

Mutational meltdown or controlled chain reaction: The dynamics of rapid plastome evolution in the hyperdiversity of Poaceae

The study of genomic structural evolution associated with accelerated evolutionary rates that result in avoidance of meltdown and increase biodiversity is becoming ever more possible as the number of available plastomes increases. To more comprehensively analyze rate heterogeneity among monocots and within Poaceae, we sequenced plastomes from four Poaceae species, combined them with publicly available data from ~200 plastomes, and conducted comparative analyses to quantify the pattern of rate heterogeneity between different lineages, functional groups, and periods of evolutionary time. We compared structural differences across the Poaceae to quantify how changes in plastome size correspond to different genomic subunits and the evolution of IR–SC junction boundaries. The substitution rates among ancestral Poaceae were inferred to be exceptionally rapid compared to other monocots but slowed after divergence into extant lineages, which could not be sufficiently explained by positive selection. As such, rapid rates in the ancestral lineage leading to Poaceae might be more closely linked to large-scale structural changes like the loss of ycf1 and ycf2. The total increase in plastome size across Poaceae was positively correlated with the total length of intergenic spacers, tandem repeats, and dispersed repeats as well as large single copy, and inverted repeats (IRs). The continuous evolution of IR–SC junction boundaries was asynchronous with sizes of total genome and subunits across Poaceae. Future work is needed to better understand what factors in ancestral Poaceae evolved to harness such rapid rates of plastome evolution, avoid a mutational meltdown, and escape the stagnation of strong purifying selection as well as if these factors could be utilized to synthetically control rates.     

猫后内侧上雪氏区视神经元对运动棒反应的取向和方向特征

猫后内侧上雪区（ｐｏｓｔｅｒｏｍｅｄｉａｌｌａｔｅｒａｌｓｕｐｒａｓｙｌｖｉａｎａｒｅａ,ＰＭＬＳ）的绝大多数神经元（１７１／２００）对运动棒的取向调谐,６２％（１２４／２００）细胞的取向调谐宽度（半高波宽）小于９０°：按方向选择性和取向选择性可分辨出几类特征明显的细胞类型：１、强取向和强方向选择性细胞;２、强取向调谐的双向选择细胞;３、弱取向调谐的强方向选择细胞;４、无取向无方向选择性细胞;以及５、特征不明显的或中间类型细胞。它们与最近光学记录揭示的鹰猴中颞叶视区（ｍｉｄｄｌｅｔｅｍｐｏｒａｌｖｉｓｕａｌａｒｅａ,ＭＴ）的组织有很好的吻合。     

N-(2-吡啶基)-N'-苯基脲对几种作物种子根、芽生长影响的回归分析

N-（2-吡啶基）-N'-苯基脲（2PU）,属苯基脲衍生物,具有细胞分裂素活性,有关其合成和应用的研究未见报道。作者合成了2PU并进行了生物效应试验研究。结果表明,2PU对作物种子萌发时胚根、胚芽的生长具有明显的促进作用,其根、芽生长与2PU浓度之间的关系符合Y=a＋bX＋eX2＋的数学模型。2PU对小麦根芽和赤豆根芽生长最佳浓度分别是0.001～0.0lppm、0.005～0.05ppm,对黄豆根生长以0.001～0.06ppm最佳。     

猪肝刺激物质pHSS对离体肝细胞DNA合成的影响

应用[~3H]TdR掺入离体培养大鼠肝细胞DNA的方法,测定由本室提取的pHSS的生物活性。结果表明,pHSS可显著促进原代培养大鼠肝细胞的DNA合成,其促进率约为对照组的10倍左右。培养液中血清浓度对pHSS的生物活性表达有显著影响,不同浓度血清可以使pHSS表现出不同的量效关系,这些结果在Buffello大鼠肝细胞系的实验中得到进一步证实。在低剂量pHSS的刺激下,不同年龄大鼠肝细胞的[~3H]TdR掺入率无显著差异。但高剂量时,pHSS对幼鼠作用不明显。     

木瓜蛋白酶PPAⅢ自水解作用

木瓜蛋白酶ＰＰＡⅢ自水解作用王秀艳,周慧,葛玉斌,李惟（吉林大学分子生物学系,长春１３００２３）ＰＰＡⅢ、ｐａｐａｉｎ、ｐｅｐｓｉｎｅ、ｓｔｅｍｂｒｏｍｅｌａｉｎ等都属于以Ｃｙｓ－ＳＨ为活性中心的酶,同种分子之间存在着一种相互切割的趋势,称为酶自水解...