夏季苹果新梢生理指标与抗苹果绵蚜的关系

研究苹果生理指标与其对苹果绵蚜(Eriosoma lanigerum Hausmann)抗性的关系,为筛选培育抗性品种,实现持续有效治理苹果绵蚜提供依据.田间调查不同苹果品种对苹果绵蚜的抗性,测定比较各品种正常枝条生理指标,以及被苹果绵蚜危害后生理指标的变化.结果表明,正常枝条中可溶性糖(r=0.99)、蛋白质(r=0.86)含量与感蚜率呈正相关;氨基酸含量与感蚜率呈负相关(r=-0.96);酚类物质和4种酶活性与苹果感蚜率均不存在明显相关性.被害后昭锦108可溶性糖含量有所下降,红富士、金冠分别上升1.4％、7.0％;蛋白质、氨基酸、酚类物质含量均有所下降,其中红富士总酚含量明显下降,达23.5％,总酚下降率与感蚜率呈正相关(r=0.94);超氧化物歧化酶(Superoxide Dismutase,SOD)、过氧化氢酶(Catalase,CAT)活性均上升,其中CAT变化率与感蚜率存在相关性(r=-0.92),昭锦108 CAT活性明显上升,达91.2％;多酚氧化酶(Polyphenol Oxidase,PPO)、过氧化物酶(Peroxidase,POD)活性增减不一;金冠4种酶活性均上升.研究表明,对苹果绵蚜抗性较强的品种:可溶性糖、蛋白质含量较低,游离氨基酸含量较高;受害后可溶性糖含量下降,总酚含量下降率较低,游离氨基酸含量下降率较高.酶活性对抗蚜性的影响不明显.     

水氮互作对拔节期黍稷根系生理特性的影响

盆栽试验条件下,以‘5283黄’和‘晋黍5号’为试验材料,采用3个水分水平×3个氮肥水平,研究水氮互作对拔节期黍稷根系生理特性的影响。结果显示:(1)水分条件相同时,施氮均使黍稷根重、总根长、总表面积增加,根冠比则下降;施肥量相同时,适量灌水也相应促进了黍稷根系以上各形态指标上升,根冠比则下降。(2)水分胁迫下适量增施氮肥均能够在一定程度上使黍稷根系中游离脯氨酸、可溶性糖和可溶性蛋白含量下降,黍稷根系SOD活性和POD活性均降低,降低了黍稷根系膜脂过氧化程度,减轻了水肥胁迫对黍稷根系的伤害,但各指标下降幅度因不同水分和肥力条件及品种不同而存在明显差异。(3)‘5283黄’在重度干旱胁迫及缺氮条件下根系的渗透调节能力和抗氧化酶活性均强于‘晋黍5号’。研究表明,合理的水肥互作处理可以有效诱导黍稷根系渗透调节能力和保护酶系统活性增强,减轻逆境胁迫的伤害,提高其抗旱和耐瘠薄能力。     

GPR15–C10ORF99 functional pairing initiates colonic Treg homing in amniotes

Regulatory T lymphocyte (Treg) homing reactions mediated by G protein‐coupled receptor (GPCR)–ligand interactions play a central role in maintaining intestinal immune homeostasis by restraining inappropriate immune responses in the gastrointestinal tract. However, the origin of Treg homing to the colon remains mysterious. Here, we report that the C10ORF99 peptide (also known as CPR15L and AP57), a cognate ligand of GPR15 that controls Treg homing to the colon, originates from a duplication of the flanking CDHR1 gene and is functionally paired with GPR15 in amniotes. Evolutionary analysis and experimental data indicate that the GPR15–C10ORF99 pair is functionally conserved to mediate colonic Treg homing in amniotes and their expression patterns are positively correlated with herbivore diet in the colon. With the first herbivorous diet in early amniotes, a new biological process (herbivorous diet short‐chain fatty acid‐C10ORF99/GPR15‐induced Treg homing colon immune homeostasis) emerged, and we propose an evolutionary model whereby GPR15–C10ORF99 functional pairing has initiated the first colonic Treg homing reaction in amniotes. Our findings also highlight that GPCR–ligand pairing leads to physiological adaptation during vertebrate evolution.     

Essence determines phenomenon: Assaying the material properties of biological condensates

Intracellular spaces are partitioned into separate compartments to ensure that numerous biochemical reactions and cellular functions take place in a spatiotemporally controlled manner. Biomacromolecules including proteins and RNAs undergo liquid–liquid phase separation and subsequent phase transition to form biological condensates with diverse material states. The material/physical properties of biological condensates are crucial for fulfilling their distinct physiological functions, and abnormal material properties can cause deleterious effects under pathological conditions. Here, we review recent studies showing the role of the material properties of biological condensates in their physiological functions. We also summarize several classic methods as well as newly emerging techniques for characterization and/or measurement of the material properties of biological condensates.     

Exploring morphological evolution in relation to habitat moisture in the moss genus Fissidens using molecular data generated from herbarium specimens

Morphological evolution in mosses has long been hypothesized to accompany shifts in microhabitats, which can be tested using comparative phylogenetics. These lines of inquiry have been developed to include target capture sequencing, which can yield phylogenomic scale data from herbarium specimens. Here, we test the relationship between taxonomically important morphological characters in the moss genus Fissidens, using a 400-locus data set generated using a target-capture approach in tandem with a three-locus phylogeny generated using Sanger sequencing. Phylogenetic trees generated using ASTRAL and Bayesian inference were used to test the monophyly of subgenera/sections. These trees provide the basis for ancestral character state reconstructions and phylogenetic correlation analyses for five morphological characters and characters related to the moisture habitat, scored from the literature and by specimen inspection. Many of these characters exhibit statistically significant phylogenetic signal. Significant correlations were found between the limbidium (phyllid/leaf border of the gametophyte) and habitat moisture niche breadth, which could be interpreted as the more extensive limbidium enabling species to survive across a wider variety of habitats. We also found correlations between costa anatomy, peristome morphology, and the limbidium, which could reflect the evolutionary recruitment of genetic networks from the gametophyte to the sporophyte phase. The correlation found between average habitat moisture and the sexual system indicates that dioicous and polyoicous species are more likely to be found in moist habitats and that these higher moisture levels could be particularly, reproductively advantageous to species with separate sexes.     

Synthesis of Pogostone-Inspired Dehydroacetic Acid Derivatives and Their Antifungal Activity against Sclerotinia sclerotiorum (Lib.) de Bary

In an effort to exploit the natural antifungal pogostone, its simplified scaffold dehydroacetic acid (DHA) was used as a lead compound to semi-synthesize 56 DHA derivatives ( I1 – 48 , II , III , and IV1 – 6 ). Among them, compound IV4 exhibited the most potent antifungal activity with 11.0 μM EC₅₀ against mycelial growth of Sclerotinia sclerotiorum (Lib.) de Bary whose sclerotia production was also completely suppressed at this concentration. Furthermore, IV4 could completely inhibit infection cushion formation of S. sclerotiorum on rape leaves and achieved a preventive efficacy of 90.2 % at 500 μM, which was on the same level as that of commercial boscalid at 30 μM (88.7 %). The results of physiological and ultrastructural studies indicated that IV4 might disrupt the cell membrane permeability or induce the imbalance of mitochondrial membrane potential homeostasis to exert the antifungal mode of action. Besides, the robust and predicative three-dimensional quantitative structure-activity relationship (3D-QSAR) models were developed and discussed herein.     

抗生素抗性基因在环境中的传播扩散及抗性研究方法

抗生素在医药、畜牧和水产养殖业的大量使用造成了环境中抗性耐药菌和抗性基因日益增加,抗生素抗性基因作为一种新型环境污染物引起人们的广泛关注.本文综述了近年来国内外有关抗生素抗性基因的研究进展,其在水、土壤、空气等环境介质中和动,植物体内的传播扩散,以及开展环境中抗生素抗性基因研究的必要性,重点介绍了有关抗生素抗性（包括抗性细菌和抗性基因）的研究方法,指出抗性基因研究中存在的问题,并对未来的相关研究进行了展望.     

锰胁迫下盐肤木锰富集及生理响应特征

为揭示盐肤木(Rhus chinensis)锰积累特征与耐受机制,该研究通过盆栽试验方法,分析0(CK)、1、5、10和20 mmol·L^-1Mn²⁺胁迫对半年生盐肤木幼苗生长、生理生化特征及其锰富集特征的影响。结果表明：(1)盐肤木在Mn²⁺浓度为0～10 mmol·L^-1条件下生长发育状况良好,且在5 mmol·L^-1Mn²⁺处理下叶片舒展,叶片颜色较深,生长最佳,而在20 mmol·L^-1Mn²⁺条件下部分叶片出现褐色斑点、萎蔫卷边的现象;随着Mn²⁺浓度的升高,盐肤木幼苗的生物量呈先升高后下降的趋势,并在5 mmol·L^-1Mn²⁺胁迫时最高。(2)随着Mn²⁺浓度的升高,盐肤木叶片中光合色素含量呈先升后降的趋势,且在Mn²⁺浓度为5 mmol·L^-1时达到峰值。(3)随着M...     

祁连山中部低海拔地区青海云杉径向生长的气候响应机制

利用生理模型开展树木径向生长的气候响应机制研究对理解树木生长的生理机制、预估气候变化情景下森林生态系统的变化、提供森林保护管理的建议有重要意义。以祁连山中部低海拔地区青海云杉树轮记录为依据,利用Vaganov-Shashkin模型模拟青海云杉(Picea crassifolia)的径向生长,探讨青海云杉径向生长的生理机制。结果表明:降水对祁连山中部低海拔地区青海云杉径向生长起着决定性作用,5—8月份的降水直接影响当年青海云杉的径向生长,9月份的降水量影响翌年青海云杉的径向生长。根据本研究结果,水分是限制青海云杉径向生长的主要因子,建议青海云杉人工林种植时,可在5—8月份对青海云杉增加灌溉量。