基于生态位模型预测野生油茶的潜在分布

油茶(Camellia oleifera)是我国第一大木本油料作物, 野生油茶是油茶育种的宝贵遗传资源。本研究从中国数字植物标本馆(CVH, http://www.cvh.org.cn/)获得可靠的野生油茶分布点数据, 结合气象和土壤数据, 分别应用最大熵(MaxEnt)模型和规则集遗传算法(GARP)模型构建了野生油茶的生态位模型, 预测了野生油茶的潜在分布区, 并分析了影响野生油茶分布的主要环境变量。根据生态位模型预测的分布概率值, 对野生油茶的潜在分布区划分适生等级, 并与主要油茶产地的实际分布数据进行比较, 以验证适生等级划分的可靠性。结果表明, 两种模型的预测结果均能较好地反映油茶的分布情况。GARP模型预测的潜在分布区更广, 而MaxEnt模型的预测结果更精确。两种模型的预测结果均显示, 野生油茶的潜在分布区大部分位于中国, 但在中南半岛也有部分分布。MaxEnt模型预测的野生油茶在中国的潜在分布区与我国亚热带常绿阔叶林的分布区基本吻合, 高适生区主要可以分为3大区域: (1)东北-西南走向的武夷山脉及附近的群山区域; (2)东西走向的南岭山脉及附近的群山区域; (3)东北-西南走向的武陵山脉及附近的群山区域。MaxEnt模型分析显示, 影响野生油茶分布的主要环境变量是昼夜温差月均值、最干季降水量与最暖季降水量。油茶生长面积较大的地区绝大部分都位于MaxEnt模型预测的中、高适生区, 说明适生等级的划分较可靠。实地考察显示, 生态位模型的预测结果对于寻找野生油茶资源具有较高的参考价值。此外, 本研究也充分显示, 利用中国数字植物标本馆的植物分布数据, 结合相应的环境数据构建生态位模型, 有助于了解作物野生近缘种的地理分布。     

石韦不同极性萃取物体外降血糖活性研究北大核心CSCD

为进一步明确石韦对α-葡萄糖苷酶和α-淀粉酶抑制作用机制,该研究以石韦95%乙醇提取物的不同极性萃取物为试材,阿卡波糖为阳性对照,采用pNPG法(p-nitrophenyl-α-D-glucopyranoside,pNPG)、DNS法(3,5-dinitro salicylic acid,DNS)考察石韦不同极性萃取物的α-葡萄糖苷酶和α-淀粉酶抑制活性,并采用酶促动力学方法与Lineweaver-Burk曲线分析最强活性萃取物对α-葡萄糖苷酶的抑制作用类型,以期为石韦的进一步开发利用提供科学依据。结果表明:石韦水萃取物对α-葡萄糖苷酶和α-淀粉酶的抑制作用最强,其IC_(50)值分别为(4.71±0.72)μg·mL^(-1)、IC_(50)=(48.40±0.32)μg·mL^(-1),并显著强于其他萃取物(P<0.05),且对α-葡萄糖苷酶抑制作用比阿卡波糖强,对α-淀粉酶抑制作用弱于阿卡波糖。阿卡波糖对α-葡萄糖苷酶和α-淀粉酶抑制作用的IC_(50)值分别为(2857.36±1.35)μg·mL^(-1)和(16.41±0.63)μg·mL^(-1)。酶促动力学显示水萃取物对α-葡萄糖苷酶为可逆性抑制,Lineweaver-Burk曲线显示为竞争性抑制。综上结果表明,石韦水萃取物具有较好的α-葡萄糖苷酶和α-淀粉酶抑制活性,是一种胃肠道副作用小、天然α-葡萄糖苷酶抑制剂来源。     

Phytochrome B regulates jasmonic acid-mediated defense response against Botrytis cinerea in Arabidopsis

The phytochrome B mediated light signaling integrates with various phytohormone signalings to control plant immune response. However, it is still unclear whether phyB-mediated light signaling has an effect on the biosynthesis of jasmonate during plant defense response against Botrytis cinerea. In this study, we demonstrated that phyB-mediated light signaling has a role in this process. Initially, we confirmed that phyb plants were obviously less resistant to B. cinerea while phyB overexpressing plants showed significantly enhanced resistance. We also found that the expression of numerous JA biosynthesis genes was promoted upon treatment with red or white light when compared to that of darkness, and that this promotion is dependent on phyB. Consistent with the gene expression results, phyb plants accumulated reduced pool of JA-Ile, indicating that phyB-mediated light signaling indeed increased JA biosynthesis. Further genetic analysis showed that light-mediated JAZ9 degradation and phyB-enhanced resistance were dependent on the receptor COI1, and that pif1/3/4/5 (pifq) can largely rescue the severe symptom of phyb. Taken together, our study demonstrates that phyB may participate in plant defense against B. cinerea through the modulation of the biosynthesis of JA.     

限制性高脂饮食对大鼠多个器官Cx43表达的影响

目的初步探讨限制性高脂饮食(脂肪含量高,热量摄入与对照一致)对大鼠多个器官Cx43蛋白表达的影响。方法Wistar大鼠52只分为普通饲料喂养组(雌雄各一组)、限制性高脂饲料喂养组(雌雄各一组),分别检测体重、Lee’s指数、血浆总胆固醇、血浆甘油三酯和血糖水平,用免疫组化检测大鼠各器官Cx43的蛋白表达。结果(1)普通饲料喂养组和限制性高脂饲料喂养组的体重、Lee’s指数、血糖、血脂均无显著性差异;(2)在雌性大鼠大脑皮质的神经元细胞、雌雄性海马区域的神经元细胞、雌性肝门管区和中央静脉周围细胞、雌雄性肾皮质近球小管上皮细胞、雌性髓袢粗段肾小管上皮细胞、雄性胰岛细胞、雄性睾丸间质限制性高脂饲料组Cx43蛋白表达明显强于普通饲料组;在雄性大鼠肝门管区和中央静脉周围细胞、雄性髓袢粗段肾小管上皮细胞、雌性胰岛细胞限制性高脂饲料喂养组Cx43表达明显弱于普通饲料组;雄性大鼠大脑皮质的神经元细胞两组无显著性差异。结论限制性高脂饮食可引起大鼠各器官Cx43差异表达。     

SPRY4-IT1 promotes survival of colorectal cancer cells through regulating PDK1-mediated glycolysis

ABSTRACT

Colorectal cancer (CRC) becomes the third leading cause of cancer-related deaths worldwide recently. The prognosis of CRC is still poor in decades, and targeted therapy is still a potential effective treatment. Long non-coding RNAs (lncRNAs) could regulate series of cellular functions and developmental processes. LncRNA-SPRY4-IT1 (GenBank ID AK024556) is derived from an intron of the SPRY4 gene, which was highly expressed in melanoma cells and affected the progression of multiple types of cancers. However, the mechanism of SPRY4-IT1 in CRC progression remains unclear. Herein, we found the high level of SPRY4-IT1 in human colorectal cancer (CRC) tissues and cells, and correlated with patients’ prognosis. We further noticed that SPRY4-IT1 regulated CRC cell growth and glycolysis, and promoting PDK1 expression. Our data further confirmed that SPRY4-IT1 regulated CRC progression targeting PDK1. We therefore thought SPRY4-IT1 could serve as a promising molecular target for the treatment of CRC.     

A fluorometric high-performance liquid chromatography procedure for simultaneous determination of methylamine and aminoacetone in blood and tissues

Methylamine and aminoacetone are endogenous aliphatic amines found in human blood and urine. They can be oxidized by semicarbazide-sensitive amine oxidase (SSAO), leading to the production of toxic aldehydes such as formaldehyde and methylglyoxal as well as hydrogen peroxide and ammonia. SSAO is localized on the surface of vascular endothelial and smooth muscle cells and of adipocytes. Increases in SSAO activity are linked to vascular disorders associated with pathological conditions such as diabetic complications, heart failure, and vascular dementia. Quantitative assessment of methylamine and acetonitrile in tissues has been hampered due to the volatility and hydrolipophilicity of these amines as well as interference by complex biological constituents. We have overcome this problem and developed an FMOC/HPLC (9-fluorenylmethyl chloroformate-Cl/high-performance liquid chromatography) method for simultaneous assessment of methylamine and aminoacetone. This method has been validated using rodent tissues with a detection limit at the picogram level. Methylamine and aminoacetone distributed unevenly among different tissues ranged from 0.1 to 27 nmol/g. To our knowledge, this is the first report on simultaneous determination of methylamine and aminoacetone in mammal tissues.     

Bilateral injection of isoproterenol into hippocampus induces Alzheimer-like hyperphosphorylation of tau and spatial memory deficit in rat

The abnormal hyperphosphorylation of tau protein is one of the hallmarks of Alzheimer disease and other tauopathies; as yet the exact role of various tau kinases in this pathology is not fully understood. Here, we show that injection of isoproterenol, an activator of cAMP-dependent kinase (PKA), into rat hippocampus bilaterally results in the activation of PKA, calcium/calmodulin-dependent kinase II and cyclin-dependent kinase-5, inhibition of protein phosphatase-2A, hyperphosphorylation of tau at several Alzheimer-like epitopes and a disturbance of spatial memory retention 48 h after the drug injection. These findings suggest the involvement of PKA and PKA-mediated signaling pathway in the Alzheimer-like tau hyperphosphorylation and memory impairment.     

UHRF2 promotes DNA damage response by decreasing p21 via RING finger domain

Objectives

To investigate the interaction of E3 ubiquitin ligase UHRF2 with p21 and the mechanism of UHRF2 in repairing DNA damage caused by hydroxyurea (HU) in HEK293 cells.

Results

Western blotting indicated that the overexpression of UHRF2 reduced the level of p21, particularly in HEK293 cells. Immunoprecipitation and immunofluorescence staining reveled that UHRF2 combined with p21 in the nucleus. In addition, UHRF2 degraded p21 through ubiquitination and shortened the half-life of p21. UHRF2 could repair DNA damage caused by HU treatment, which was impaired by the inhibition of p21 in HEK293 cells.

Conclusions

UHRF2 may negatively modulate p21 to regulate DNA damage response, suggesting a novel pathway of UHRF2 repairing DNA damage through the partial regulation of p21.

     

西昌黄联耕地养分的输入输出研究

西昌黄联耕地养分的输入输出研究雷圣远（四川农业大学,雅安６２５０１４）ＩｎｐｕｔａｎｄＯｕｔｐｕｔｏｆＳｏｉｌＮｕｔｒｉｅｎｔｓａｔＨｕａｎｇｌｉａｎｏｆＸｉｃｈａｎｇ．￥ＬｅｉＳｈｅｎｇｙｕａｎ（ＳｉｃｈｕａｎＡｇｒｉｃｕｌ－ｔｕｒａｌＵｎｉｖｅｒ...