过表达桑树色氨酸脱羧酶基因(MnTDC)转基因烟草提高其耐盐性

褪黑素在植物生长、发育、生物与非生物胁迫中发挥重要作用。色氨酸脱羧酶(tryptophan decarboxylase, TDC)是褪黑素生物合成中第一个重要的酶。本研究克隆川桑TDC基因,并将其转入烟草中过表达,探讨MnTDC在盐胁迫下的作用机制。结果表明,成功构建过表达载体pLGNL-MnTDC,并经过农杆菌介导的愈伤组织转化获得3个独立转基因系。GUS染色、基因组PCR鉴定证明MnTDC成功转化到烟草株系中。qRT-PCR结果表明MnTDC在3个转基因烟草株系中的转录水平显著高于野生型(WT)。UPLC-MS/MS结果表明转基因株系显著提高了褪黑素的生物合成量。盐胁迫下,MnTDC过表达烟草与野生株系烟草相比,耐盐性显著增强。转基因烟草株系中的过氧化氢酶(CAT)、超氧化物歧化酶(SOD)及过氧化物酶(POD)活性均显著高于野生株系烟草,脯氨酸(Pro)等调节渗透压物质的含量和ERD10C等调节渗透压的基因表达量显著高于野生株系烟草,转基因株系中丙二醛(MDA)含量比野生株系烟草低。研究结果表明,MnTDC通过调节烟草细胞中褪黑素的含量进而影响了烟草植株整体的耐盐性。本研究初步揭...     

土壤分析试剂量估算系统的设计与开发

通过对土壤试剂量估算过程中所涉及的土壤指标、试剂和药品等知识的分析和研究,利用计算机技术,开发了基于网络化的网络决策系统。阐述了土壤试剂量估算系统的体系结构,并对其主要功能模块和其实现进行了描述。     

基于双向晶闸管的有载分接开关启动机构的研究

采用双向晶闸管作为启动机构的分接开关,利用光电耦合器作为控制信号的收发,构成了完全由硬件电路控制操作的新型启动机构,利用变压器的二次侧电压供电,监测及控制,保证有载自动调压分接开关投入运行的可靠性。实验结果表明,完全可以取代蓄电池作为有载自动调压分接开关的启动机构,同时更加科学、安全、可靠。     

Saquayamycin B1 Suppresses Proliferation,Invasion, and Migration by Inhibiting PI3K/AKT Signaling Pathway in Human Colorectal Cancer Cells

Moromycin B (Mor B), saquayamycin B₁ (Saq B₁), saquayamycin B (Saq B), and landomycin N (Lan N), four angucyclines produced by the marine-derived actinomycete Streptomyces sp., are a class of polyketone compounds containing benzanthracene. Here, the structure–activity relationship of these four compounds was analyzed in human colorectal cancer (CRC) cells. Saq B₁, which showed the strongest cytotoxicity with an IC₅₀ of 0.18–0.84 µM for CRC cells in MTT assays, was employed to test underlying mechanisms of action in SW480 and SW620 cells (two invasive CRC cell lines). Our results showed that Saq B₁ inhibited CRC cell proliferation in a dose- and time-dependent manner. Notably, lower cytotoxicity was measured in normal human hepatocyte cells (QSG-7701). Furthermore, we observed proapoptosis, antimigration, and anti-invasion activities of Saq B₁ in CRC cells. At the same time, the protein and mRNA expression of important markers related to the epithelial–mesenchymal transition (EMT) and apoptosis changed, including N-cadherin, E-cadherin, and Bcl-2, in Saq B₁-treated CRC cells. Surprisingly, the PI3K/AKT signaling pathway was shown to be involved in Saq B₁-induced apoptosis, and in inhibiting invasion and migration. Computer docking models also suggested that Saq B₁ might bind to PI3Kα. Collectively, these results indicate that Saq B₁ effectively inhibited growth and decreased the motor ability of CRC cells by regulating the PI3K/AKT signaling pathway, which provides more possibilities for the development of drugs in the treatment of CRC.     

气候变化情景下毛竹潜在分布及动态预测

为探究毛竹的潜在分布及其动态变化,并确定对其分布起主导作用的环境变量,文章基于MaxEnt预测模型,利用环境变量图层及316个毛竹分布点数据研究毛竹地理分布的变化。结果显示：1）限制毛竹分布的主要环境变量为最干月降水量、年均降水量、最冷月最低温、年平均温、温度年较差和海拔;2）当前毛竹的潜在适生区主要位于中国东南部,与亚热带季风气候区大致重叠,高适生区主要位于总适生区的东部和西北部;3）在未来气候情景下,毛竹总适生区面积有所缩减,各不同等级适生区面积变化大,其中高适生区面积大幅度缩减。研究获得的毛竹适生区变化趋势可为毛竹培育、引种以及入侵防治提供参考。     

Paspalines C–D and Paxillines B–D: New Indole Diterpenoids from Penicillium brefeldianum WZW-F-69

Five new indole diterpenoids named paspaline C–D (1–2) and paxilline B–D (3–5), as well as eleven known analogues (6–16), were identified from fungus Penicillium brefeldianum strain WZW-F-69, which was isolated from an abalone aquaculture base in Fujian province, China. Their structures were elucidated mainly through 1D- and 2D-NMR spectra analysis and ECD comparison. Compound 1 has a 6/5/5/6/6/8 hexacyclic ring system bearing 2,2-dimethyl-1,3-dioxocane, which is rare in natural products. Compound 2 has an unusual open F-ring structure. The cytotoxic activities against 10 cancer cell lines and antimicrobial activities against model bacteria and fungi of all compounds were assayed. No compound showed antimicrobial activity, but at a concentration of 1 μM, compounds 1 and 6 exhibited the highest inhibition rates of 71.2% and 83.4% against JeKo-1 cells and U2OS cells, respectively.     

Eremophilane-Type Sesquiterpenes from a Marine-Derived Fungus Penicillium Copticola with Antitumor and Neuroprotective Activities

Chemical examination of a marine sponge-associated Penicillium copticola fungus resulted in the isolation of ten undescribed eremophilanes, namely copteremophilanes A–J (1–10), along with two new glycosides, 5-glycopenostatin F (11) and 5-glucopenostatin I (12). Their structures were determined by extensive spectroscopic data, in association with ECD data and chemical conversions for configurational assignments. Analogs 1, 2, and 10 represent a group of uncommon skeletons of eremophilanes with an aromatic ring and a methyl migration from C-5 to C-9, and analogs 11 and 12 are characteristic of a PKS scaffold bearing a glucose unit. The incorporation of a chlorinated phenylacetic unit in 3–9 is rarely found in nature. Analog 7 showed neuroprotective effect, whereas 8 exhibited selective inhibition against human non-small cell lung cancer cells (A549). This study enriched the chemical diversity of eremophilanes and extended their bioactivities to neuroprotection.     

Structures and Biological Activities of Secondary Metabolites from Trichoderma harzianum

The biocontrol fungus Trichoderma harzianum, from both marine and terrestrial environments, has attracted considerable attention. T. harzianum has a tremendous potential to produce a variety of bioactive secondary metabolites (SMs), which are an important source of new herbicides and antibiotics. This review prioritizes the SMs of T. harzianum from 1988 to June 2022, and their relevant biological activities. Marine-derived SMs, especially terpenoids, polyketides, and macrolides compounds, occupy a significant proportion of natural products from T. harzianum, deserving more of our attention.     

市场经济对云南规划烟区耕地资源的影响分析

为了掌握目前云南规划烟区在耕地资源配置方面的详细情况,以及市场经济对云南规划烟区坡度影响,以最新烤烟种植区划成果数据和坡度格点化数据为基础,分析各州市烤烟种植区划核心区,优质区和适宜区在坡度类型的分布状况和差异,在此基础上结合各州市农村人均可支配收入数据,分析市场经济对云南烤烟种植区坡度的影响.结果表明:云南省烤烟规划...     

生殖激素产品的应用和发展趋势

生殖激素是调控动物体内复杂生殖过程并影响繁殖性能的一系列的重要激素.近年来,利用生殖激素的批次化生产繁殖技术被广泛使用,提高了母猪的繁殖效率,促进了养猪业向集约化和规模化方向的发展.目前在批次化生产过程中主要采用孕马血清促性腺激素(PMSG)和人绒毛膜促性腺激素(HCG)以及化学类激素进行繁殖调控.但是这些产品的应用仍...