HPLC-ELSD法测定家桑野桑植株中1-脱氧野尻霉素的含量

采用HPLC-ELSD法对桑植株各部位所含的1-脱氧野尻霉素(DNJ)进行了含量测定,使用TSKgel Am-ide-80(4.6 mm×250 mm,5μm)色谱柱,流动相为:乙腈-水(84∶16,6.5 mM醋酸铵),流速为1.00 mL/min,柱温:30℃,线性范围为0.505μg～20.2μg(r=0.9991,n=6),平均回收率为94.95%(n=5),RSD=1.98。测定结果表明,野桑叶、嫩枝和根皮部位的DNJ含量较高,而家桑的叶、枝皮和根皮中含量较高。本方法准确度高、重现性好,能快速检测桑树资源及类似植物和相关产品中1-脱氧野尻霉素的含量。     

应用比色法检测枯草芽孢杆菌变异菌株中1-脱氧野尻霉素含量

为寻找测定枯草芽孢杆菌黑色变种突变株Bacillus subtilis var.niger-231(B-231)的发酵液中1-脱氧野尻霉素(1-Deoxynojirimycin,DNJ)的新方法并提高其产发酵液中DNJ的含量。在有铜离子的存在下,DNJ与二硫化碳反应,用有机溶剂对产物萃取后在440 nm进行光度测定,得到DNJ含量。再采用紫外诱变方法处理突变株B-231。绘制了检测DNJ标准品的标准曲线,对测定DNJ的新方法做了精密度、灵敏度、准确度以及产物的稳定性的探讨,设计正交试验优化了反应条件,并将此方法运用到细菌发酵液中DNJ含量的测定中,通过遗传诱变手段处理原始细菌B-231,最终筛选到一株高产DNJ的菌株,命名为B.subtilis var.niger-431(B-431),DNJ含量达87.3 mg/L,其产生DNJ的量较原始菌株原突变株提高了4.2倍。首次提出了一种快速测定细菌发酵液中的1-脱氧野尻霉素的新方法,紫外诱变手段使细菌产生DNJ的能力有较大提高。     

沉淀聚合法制备1-脱氧野尻霉素分子印迹聚合物微球及其性能研究

本研究制备了1-脱氧野尻霉素分子印迹聚合物微球,考察溶剂、反应时间对分子印迹聚合物产率以及性能的影响。以1-脱氧野尻霉素为模板分子,α-甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂,采用沉淀聚合法合成分子印迹微球,采用静态吸附及扫描电镜(SEM)的方法对微球进行表征。结果表明,当反应时间为24 h、乙腈为溶剂时,所制得印迹聚合物微球的形貌和吸附性能较好,对1-脱氧野尻霉素与N-甲基-1-脱氧野尻霉素的选择性分离因子α为2.26,说明分子印迹聚合物微球对1-脱氧野尻霉素分子有特异性吸附和识别能力。     

桑枝中脱氧野尻霉素的提取及其降血糖效果的研究

从桑不同组织部位中提取1-脱氧野尻霉素（DNJ）,测定其含量,并通过动物实验分析桑枝提取液的降血糖效果。结果表明：桑芽、桑枝和发芽前桑皮中DNJ含量高于桑根和发芽后桑皮,而桑枝的DNJ含量最高,可达0．15％。60℃、80％乙醇、时间2h为夏伐桑枝中DNJ的最佳提取条件,提取率达0．176％。而在同等条件下,乙醇溶剂的提取效果好于蒸馏水。灌胃等量桑枝水提液、二倍量桑枝水提液、盐酸二甲双胍片的高血糖小白鼠组的血糖值四周后分别下降了7．63％、15．72％、18．41％,说明桑枝提取液有明显的降血糖效果。     

应用柱前衍生化高效液相色谱法开辟了一种简单、快速的DNJ产生菌的筛选途径

【目的】应用柱前衍生化高效液相色谱法筛选产1-脱氧野尻霉素(DNJ)菌株,并对其进行系统鉴定。【方法】利用芴甲氧酰氯(FMOC-Cl)柱前衍生化高效液相色谱法筛选DNJ产生菌;通过形态特征、培养特征、生理生化特征以及16S rRNA序列相似性分析等多项分类方法对DNJ产生菌进行鉴定;在10 L发酵罐水平进行发酵研究,利用FMOC-Cl柱前衍生化高效液相色谱法测定DNJ含量。【结果】从80株具有α-糖苷酶抑制剂活性的土壤放线菌中筛选得到一株DNJ产生菌,菌株编号为PW409,初步确定为戈壁三素链霉菌(Streptomyces gobitrici);发酵研究表明,DNJ为链霉菌PW409的次级代谢产物,发酵液中DNJ浓度为12.1 mg/L。【结论】首次将FMOC-Cl柱前衍生化高效液相色谱法应用于DNJ产生菌的筛选,并首次报道从戈壁三素链霉菌发酵液中鉴定到DNJ。     

大气氟污染源附近食桑昆虫中氟的积累和分布

对大气F污染源附近野桑蚕,桑赤蠖和桑蚕体内的氟化物含量和器官分布进行了研究,结果表明,污染源附近食桑昆虫体有较高的氟化物含量,且食桑昆虫体的氟化物含量随着离污染源的距离增大而降低,野桑蚕,桑赤蠖和桑蚕的氟化物含量与桑叶的氟化物含量有极显著的线性正相关性,食桑昆虫不同器官间的氟化物积累量也存在较大差异,其消化管是食桑昆虫的主要氟化物积累器官。     

柘叶饲养对家蚕消化液中抗核多角体病毒（BmNPV）相关蛋白活性的影响

为探讨柘叶Cudrania tricuspidata饲养家蚕Bombyx mori易感染核多角体病毒（BmNPV）的机制, 本实验比较研究了分别以柘叶和桑叶Morus alba饲养家蚕后其消化液中抗病毒蛋白活性的差异。结果表明: 家蚕经柘叶饲养后消化液中红色荧光蛋白（red fluorescent protein, RFP）的强度无明显变化, 但柘叶饲养蚕消化液中脂肪酶、 胰蛋白酶的活性显著低于桑叶饲养蚕, 柘叶饲养蚕消化液中脂肪酶和胰蛋白酶的活性分别为1 421.71±202.60 U/L和19.67±8.17 U/mL, 桑叶饲养蚕脂肪酶和胰蛋白酶的活性分别为1 976.03±139.92 U/L和199.18±181.71 U/mL。这些结果说明, 消化液中脂肪酶和胰蛋白酶的活性水平低与柘叶饲养蚕易感染核型多角体病毒（BmNPV）可能相关。     

响应面分析法优化家蚕1-脱氧野尻霉素的稀酸浸提工艺

本文以稀HCl从蚕粉中提取1-脱氧野尻霉素(1-deoxynojirimycin,1-DNJ),通过单因素试验确定提取影响因素的水平,并采用响应面法研究料液比分数、浸提温度和浸提时间对蚕粉1-DNJ提取工艺的影响。其中1-DNJ含量测定采用9-芴基氯甲酸甲酯(FMOC-Cl)衍生化法,并用反相高效液相色谱对其衍生物进行测定。1-DNJ高效液相色谱检测谱图表明,通过液相色谱荧光可以检测蚕粉来源的1-DNJ。响应面优化实验结果表明,1-DNJ的最佳提取条件为:提取时间3.3h,浸提温度72.9℃,料液比分数为1:282。在此条件下,1-DNJ的理论提取率为0.493%,实际提取率为0.487%,相对误差为1.2%。本研究初步建立了稀酸浸提家蚕1-DNJ的二次多项数学模型,确定其最佳提取工艺条件,为工业化生产提供参考。     

桑-蚕系统中镉的吸收、累积与迁移

对桑－蚕系统中镉的吸收,累积与迁移行为研究结果表明：（１）桑树对土壤镉污染有一定的耐性,桑树镉累积量和相对累积率与土壤镉浓度的关系可分别用回归方程Ｔａ＝ａ＋ｂｌｏｇ（Ｓｃ）和ｌｏｇ（Ｒａ）＝ａ＋ｂｌｏｇ（Ｓｃ）描述。（２）随着土壤镉浓度的增加,镉在桑树根部的分布率明显增加,地上部分的分布率有所降低,运转到叶片的比率明显降低。（３）蚕体,蚕砂和蚕茧的镉含量,镉累积量,随着桑叶镉含量的增加而增加。     

家蚕在人工饲料饲养下若干因素对生长的影响

为了探索家蚕人工饲料饲养实用化的途径,对人工饲料的配方、剂型以及幼虫的生活习性等进行了研究。结果表明:1.光照(全明或昼明夜暗)条件下人工饲料饲养的蚕发育较快而整齐,且增加了对CPV(质型多角体病毒)的抵抗力。2.下述配方较好:桑叶粉45克,豆饼粉25克,淀粉5克,石油酵母5克,蜂蜜5克,柠檬酸3克,维生素C2克,没食子酸0.4克,山梨酸0.3克,氯霉素25毫克,成型剂石花菜15克,加水250毫升。3.配方中桑叶粉含量必须保持在40%以上,质量以春叶为优。4.与桑叶饲育比较,蚕对营养成分的吸收率高,但转化率低。5.为了便于贮藏和运输,人工饲料可制成干片。     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.     

2018年中国植物科学若干领域重要研究进展

2018年中国植物科学继续呈现快速发展的态势, 我国科学家在国际植物科学主流学术刊物发表论文数量大幅增加, 取得了多项具有重要影响的成果。调控植物生长-代谢平衡实现可持续农业发展入选2018年度中国科学十大进展; 中国被子植物区系进化历史研究入选2018年度中国生命科学十大进展。以水稻为代表的农作物和果蔬等经济作物研究在国际上已呈现出明显的优势, 若干领域已从“追赶”状态跨越到“领跑”地位。该文对2018年中国科学家在植物科学若干领域取得的重要研究成果进行了概括性评述, 旨在全面追踪和报道当前中国植物科学领域的发展前沿和热点, 展示中国科学家所取得的杰出成就。     

2018年中国植物科学若干领域重要研究进展

2018年中国植物科学继续呈现快速发展的态势, 我国科学家在国际植物科学主流学术刊物发表论文数量大幅增加, 取得了多项具有重要影响的成果。调控植物生长-代谢平衡实现可持续农业发展入选2018年度中国科学十大进展; 中国被子植物区系进化历史研究入选2018年度中国生命科学十大进展。以水稻为代表的农作物和果蔬等经济作物研究在国际上已呈现出明显的优势, 若干领域已从“追赶”状态跨越到“领跑”地位。该文对2018年中国科学家在植物科学若干领域取得的重要研究成果进行了概括性评述, 旨在全面追踪和报道当前中国植物科学领域的发展前沿和热点, 展示中国科学家所取得的杰出成就。     

我国葫芦科植物离体培养研究进展

葫芦科植物包括多种瓜类蔬菜,对其进行离体培养研究具有重要的理论和实践意义。综述了国内在葫芦科植物器官培养、体细胞胚胎发生、花药培养、原生质体培养和体细胞杂交及离体遗传转化等方面取得的研究进展,并对葫芦科植物离体培养、遗传转化与育种的前景作了展望。     

2017年中国植物科学若干领域重要研究进展

2017年中国植物科学继续保持高速发展态势, 重大成果频出, 具体表现在中国植物学家在国际顶级学术期刊发表的文章数量平稳上升。中国植物科学领域的研究工作者成果精彩纷呈, 如新型广谱抗病机制的发现、水稻广谱抗病遗传基础及机制和疫霉菌诱发病害成灾机制研究等。2017年中国生命科学领域十大进展评选中, 有两项植物科学领域的研究成果入选。水稻生物学、进化与基因组学和激素生物学等领域学科发展突出。另外, 值得一提的是, 长期从事高等植物与代谢途径调控分子网络研究和水稻品种设计育种的李家洋院士的研究成果“水稻高产优质性状形成的分子机理及品种设计”荣获2017年国家自然科学一等奖。这一具有重大国际影响的开创性贡献标志着中国植物科学在该领域的国际科学前沿居于引领和卓越地位。该文对2017年中国本土科学家在植物科学若干领域取得的重要研究成果进行了系统梳理, 旨在全面追踪和报道当前中国植物科学领域发展的最新前沿动态, 与广大读者共同分享我国科学家所取得的辉煌成就。     

我国葫芦科植物离体培养研究进展

葫芦科植物包括多种瓜类蔬菜,对其进行离体培养研究具有重要的理论和实践意义.综述了国内在葫芦科植物器官培养、体细胞胚胎发生、花药培养、原生质体培养和体细胞杂交及离体遗传转化等方面取得的研究进展,并对葫芦科植物离体培养、遗传转化与育种的前景作了展望.     

Changes in aquatic vegetation in Rhine floodplain streams in Alsace in relation to disturbance

Abstract. Changes are described in aquatic vegetation in oligotrophic, groundwater-fed Rhine floodplain streams in Alsace (eastern France), resulting from disturbance. Disturbance factors include changes in nutrients, either permanent ones - effluent from a waste water treatment plant or trout hatcheries - or periodic ones: flooding. Regular inputs of high levels of phosphate and ammonia modified the macrophyte vegetation in these streams. The floristic composition, which was characteristic of oligotrophic waters upstream of the eutrophicated sector, changed to that of a eutrophic situation as originally found downstream. Periodic disturbance by floods which normally occur once a year, irregularly eutrophicates the small streams, causing the development of a mixture of eutrophic and oligotrophic species. Six macrophyte communities are distinguished, indicating different trophic levels. The aquatic vegetation is adapted to the variations of phosphate and ammonia levels. Hence, aquatic macrophytes can be used as bio-indicators of fluctuations in water nutrient levels in relation to the type of disturbance.     

Morphine-potentiated platelet aggregation in in vitro and platelet plug formation in in vivo experiments

The detailed mechanisms underlying morphine-signaling pathways in platelets remain obscure. Therefore, we systematically examined the influence of morphine on washed human platelets. In this study, washed human platelet suspensions were used for in vitro studies. Furthermore, platelet thrombus formation induced by irradiation of mesenteric venules with filtered light in mice pretreated with fluorescein sodium was used for an in vivo thrombotic study. Morphine concentration dependently (0.6, 1, and 5 microM) potentiated platelet aggregation and the ATP release reaction stimulated by agonists (i.e., collagen and U46619) in washed human platelets. Yohimbine (0.1 microM), a specific alpha(2)-adrenoceptor antagonist, markedly abolished the potentiation of morphine in platelet aggregation stimulated by agonists. Morphine also potentiated phosphoinositide breakdown and intracellular Ca(2+) mobilization in human platelets stimulated by collagen (1 microg/ml). Moreover, morphine (0.6-5 microM) markedly inhibited prostaglandin E(1) (10 microM)-induced cyclic AMP formation in human platelets, while yohimbine (0.1 microM) significantly reversed the inhibition of cyclic AMP by morphine (0.6 and 1 microM) in this study. The thrombin-evoked increase in pH(i) was markedly potentiated in the presence of morphine (1 and 5 microM). Morphine (2 and 5 mg/g) significantly shortened the time require to induce platelet plug formation in mesenteric venules. We concluded that morphine may exert its potentiation in platelet aggregation by binding to alpha(2)-adrenoceptors in human platelets, with a resulting inhibition of adenylate cyclase, thereby reducing intracellular cyclic AMP formation followed by increased activation of phospholipase C and the Na(+)/H(+) exchanger. This leads to increased intracellular Ca(2+) mobilization, and finally potentiation of platelet aggregation and of the ATP release reaction.     

Apoptosis in experimental myocardial infarction in situ and in the perfused heart in vitro

We report the appearance of apoptotic cells in experimental myocardial infarction (rabbit heart) in in situ and in vitro preparations. Apoptosis was recognized by intravital staining with Hoechst 33342 (Ho342), by nick-end labeling (TUNEL) and by DNA laddering. A steady rise in the relative number of apoptotic cardiomyocytes (apoptotic index) was noted in in situ preparations. Apoptosis was first noted 6 h after the onset of ischemia with its highest value occurring after 72 h. Apoptotic nuclei were absent in remote areas of the left and right ventricles. Apoptotic nuclei within the infarcted area showed diminished intensity of Ho342 fluorescence. Three days after ischemia, a border zone adjacent to the infarcted area consisting of apoptotic macrophages was recognized. A novel finding was the appearance of apoptotic cardiomyocytes in the isolated perfused ischemic heart. Occurring as early as 50 min after the onset of ischemia, a high apoptotic index was present adjacent to the ligature placed around the coronary artery. This observation provides the opportunity to selectively examine factors leading to apoptosis in the ischemic heart under controlled experimental conditions.