1株Pseudomonas frederiksbergensis JW-SD2的解磷特性及解磷条件研究

为探讨解磷细菌Pseudomonas frederiksbergensis JW-SD2的解磷特性及条件,检测了该菌株对不同矿质磷酸盐的溶解能力,并研究了不同碳源、氮源、温度、p H、装液量及盐离子等营养、环境因素对其解磷能力的影响。结果表明,该菌株对Ca3(PO4)2的溶解能力强于Fe PO4和Al PO4,解磷量达7.43 mmol/L。以葡萄糖作为碳源,硫酸铵作为氮源该菌株具有最大的解磷能力。同时还发现,该菌株能够在温度20~35℃,p H 4~9,装液量1/5~4/5,Na Cl浓度0~3.0%保持3.0 mmol/L以上的解磷量,具有较强的环境适应能力。     

几株侧孢芽孢杆菌解磷能力的研究

菌株BL-11、BL-12、BL-2l、BL-22是自行分离得到的4株具有解磷能力的细菌,经鉴定为侧孢芽孢杆菌(Bacillus laterosporus)。实验分别以Ca3(PO4)2、氧化乐果和水胺硫磷为唯一磷源,接种4株菌,在30℃、180r／min条件培养4d后,以钼蓝比色法测上清液中的水溶性磷含量。在以Ca3(PO4)2为唯一磷源的培养液体中菌株BL-11、BL-12的解磷能力分别为10．9l％和7．34％,均高于菌株BL-21、BL-22;而在以水胺硫磷为唯一磷源的培养液中,菌株BL-21、BL-22的解磷能力显著好于菌株BL-11、BL-12,解磷效率分别为58．98％和75．50％;而在以氧化乐果为唯一磷源的培养液中,菌株BL-21、BL-22的解磷效率分别为32．66％和29．10％,均高于菌株BL-11、BL-12。     

蔗叶堆肥中一株泡盛曲霉溶磷能力的鉴定及其对辣椒的促生效果

从甘蔗叶堆肥中分离筛选具有高效溶磷及促生功能的菌株,为微生物肥料制备提供一种可利用的菌种资源。[方法]以Ca3(PO4)2和Zn3(PO4)2为磷源,进行平板溶磷筛选实验;采用形态学特征和ITS rDNA序列分析法进行菌种鉴定;采用液体摇瓶培养测定菌株的溶磷能力;将溶磷菌接种至辣椒幼苗根部分析其促生效应。[结果]从堆肥中筛选得到1株高效溶磷真菌DC30-2-P1,经鉴定为泡盛曲霉(Aspergillus awamori),菌株在Ca3(PO4)2和Zn3(PO4)2培养基的菌落直径(d)分别为55.33 mm和45.00 mm,透明圈直径(D)分别为65.33 mm和67.67 mm,(D/d)分别为1.16和1.50,菌株溶磷效果明显;在以Ca3(PO4)2(5 g/L)为磷源的液体培养基培养至96 h,有效磷含量达到2973.85 mg/L。盆栽试验结果表明接种DC30-2-P1对辣椒生长具有明显促进作用,与无添加溶磷菌处理组比较,其地上部鲜重和干重分别增加了18.6%和43.5%,地下部鲜重和干重分别增加了30.2%和25%,株高增加了13.6%,叶绿素含量增加了44.9%,植物全磷含量和土壤有效磷含量均提高了80%以上。[结论]筛选到的菌株DC30-2-P1在溶解难溶性磷化合物、促进作物对磷的吸收和生长有良好效应,为微生物制剂的开发提供菌株资源。     

一株新的溶磷棘孢青霉菌Z32的分离、鉴定及其土壤定殖与溶磷特性

【目的】从植物根部土壤中分离到一株高效溶磷真菌Z32,进行了分类学鉴定和土壤定殖与溶磷特性的初步研究。为溶磷微生物的应用提供新的菌株。【方法】通过形态特征、培养特征和ITSrDNA序列分析方法进行菌株鉴定。通过菌株Z32在土豆液体培养基培养过程中培养液pH的变化确定溶磷菌株的溶磷能力。利用菌株土培试验,进行菌株的土壤定殖和土壤中不同形态无机磷转化试验。【结果】菌株Z32鉴定为棘孢青霉菌(Penicillium aculeatum)。菌株Z32能在4d内完全溶解固体培养基中的磷酸三钙,18h内将土豆液体培养基的pH值从7.0降低到1.5左右。菌株Z32在20℃时的定殖效果最好,21d时,菌数达到起始的9.83倍,而且能够保持到49d不消亡。在20℃时,添加菌株Z32的土培实验在21d时,土壤中Ca8H2(PO4)6·5H2O、AlPO4和FePO4等难溶无机磷向可溶性的CaHPO4转化,CaHPO4含量增加了58.83%。49d时,土壤中的Ca8H2(PO4)6·5H2O、AlPO4和和FePO4被转化后,没有随着微生物的减少而完全被固定。【结论】筛选到一株新的溶磷菌株Z32在土壤中很好定殖,能够转化土壤中多种形态的难溶无机磷为可溶性的CaHPO4,显著增加土壤中CaHPO4的含量。同时阻滞了Ca8H2(PO4)6·5H2O、AlPO4和和FePO4等难溶无机磷的固定。     

高产雷帕霉素的游动放线菌菌种的选育

以游动放线菌(Actinoplanes)BCLP-016为出发菌株,采用常压室温等离子体(ARTP)诱变技术对其孢子进行处理,并将三个不同时间处理的孢子悬液混合。稀释涂布后,根据菌株菌落形态挑取部分单菌落进行初筛,经发酵复筛后,筛选得到了一株雷帕霉素高产菌株ARTP-039,其雷帕霉素的产量可达到369.39mg/L,较出发菌株BCLP-016的产量256.86 mg/L,提高了43.81%。以筛选出的ARTP-039高产菌为出发菌株,进行传统的紫外诱变,选取高、中、低三个致死率相对应的时间对其孢子悬液进行处理,并基于核糖体工程的理论选取了链霉素、庆大霉素、利福平、氯霉素和红霉素五种抗性物质,进行抗性初筛。发酵复筛后,最终筛选得到了一株雷帕霉素高产菌株St8+Gen6+Rif9+Chl3+Er4-015,该菌株同时具有五种抗性。该菌株的摇瓶实验结果表明,发酵7d后,其雷帕霉素的产量可达到589.79mg/L,较出发菌株BCLP-016的产量,提高了129.61%,且其遗传稳定性良好。     

香蕉根际土壤解磷细菌的筛选、鉴定及解磷能力

【目的】以磷矿粉为难溶态磷,以期从香蕉根际土壤筛选出高效的解磷细菌。【方法】采用透明圈法和钼锑抗比色法分离筛选解磷细菌,通过形态学特征、生理生化试验结合16S rRNA基因序列分析及系统发育树比对鉴定其种属,并利用单因素试验方法研究不同碳源、氮源及C/N比值(40:1、20:1和8:1)对菌株溶解磷矿粉能力的影响。研究不同菌株解磷能力和培养介质pH值的变化关系。【结果】分离具有解磷能力的细菌8株,筛选出具有代表性的3个菌株B3-5-6、M-3-01和T1-4-01,初步鉴定菌株B3-5-6为嗜气芽孢杆菌(Bacillus aerophilus),M-3-01为虫内生沙雷氏菌(Serratia nematodiphila),T1-4-01为艾博丽肠杆菌(Enterobacter asburiae)。B3-5-6解磷能力与介质pH值之间存在线性负相关性(|r|=0.949 66>0.735),其相关性达到极显著水平;B3-5-6在碳源为蔗糖、氮源为(NH4)2SO4、C/N为40:1,M-3-01在碳源为葡萄糖、氮源为(NH4)2SO4、C/N为20:1,T1-4-01在碳源为乳糖、氮源为蛋白胨、C/N为20:1条件下解磷效果较好。解磷效果与初筛相比分别提高了1.12、1.17、2.55倍。【结论】不同的碳氮源、C/N值会直接影响磷细菌的解磷能力;筛选出一株解磷能力与培养介质pH之间存在着极显著相关性的细菌,其解磷机理有待进一步研究。     

三株土壤解磷细菌的分离及其解磷效果分析

旨为解决农业面源污染问题,分离鉴定土壤解磷微生物并开发复合微生物菌剂。以有机磷农药及无机难溶磷作为筛选磷源,对土壤中具有解磷能力的微生物进行分离、鉴定并对其解磷效果进行分析。从土壤中分离得到3株解磷细菌,分别命名为菌株W、Y、B;3个菌株均是革兰氏阴性菌;W菌株对敌百虫的降解能力最强,达到17.39%,B菌株对毒死蜱的降解率最强,为23.06%;3个菌株对固态难溶磷的解磷效果显著,其中B菌株解磷量最高,为96.31 mg/L;复合菌的解磷效果明显优于单菌,另外复合菌对稻田、大棚土壤解磷的促进效果显著,分别增加18.38 mg/L、14.08 mg/L。分离得到3株有效土壤解磷细菌,有一定的有机磷农药降解能力,对无机磷溶解效果较强,构建的复合菌剂对土壤解磷的促进效果显著。     

油松菌根际高效解磷钾细菌筛选与鉴定

本研究筛选出油松-褐环乳牛肝菌菌根根际土中高效解磷钾细菌并对其进行种类鉴定。采用平板稀释法自菌根际土中筛选解磷钾细菌,并用钼蓝比色法和原子吸收法分别对其液体培养5 d后的菌株进行解磷能力和解钾能力测定,筛选出高效的解磷钾细菌。同时,对筛选出的菌株进行显微观察、生物学鉴定和16Sr DNA序列分析。通过筛选得出解有机磷细菌P6和解无机磷细菌P15能力较强,其培养液中有效磷浓度分别为283 mg/L和898.5 mg/L,经鉴定P6属于节杆菌属(Arthrobacter sp.),P15为荧光假单胞菌(Pseudomonas fluorescens),以及2株能力较强的解钾细菌K1和K12,其培养液中有效钾浓度分别为21.6 mg/L,19.3 mg/L,经鉴定K1为壤霉菌属(Agromyces cerinus),K12为中华根瘤菌属(Sinorhizobium sp.)。由此可见,油松-褐环乳牛肝菌菌根根际存在高效解磷钾细菌,褐环乳牛肝菌可以通过影响根际解磷钾细菌的种类及能力来改善油松幼苗的根际磷钾营养状况。     

一株溶磷真菌筛选鉴定及其溶磷促生效果

【目的】从高产农田筛选高效溶磷微生物菌株,为溶磷微生物肥料开发提供高效菌种资源。【方法】利用菌株的形态学特性、培养特征和ITS rDNA序列分析方法进行菌株鉴定,结合液体培养和土壤培养方法研究菌株的溶磷能力,进而采用温室盆栽和田间小区试验,明确溶磷菌P83促进作物生长和提高作物产量的作用效果。【结果】溶磷菌株P83鉴定为斜卧青霉菌(Penicillium decumbens)。液体条件下培养10 d,菌株P83表现显著高效的溶磷能力,对Ca3(PO4)2(5g/L)的溶解效果,有效磷达956 mg/L,溶解率为42.68%,对湖南永和磷矿粉的溶液效果,有效磷达到152.8 mg/L;将P83菌株分别接种于施用Ca3(PO4)2、Zn3(PO4)2和磷矿粉(RP)3种磷源的盆栽试验土壤中,结果显示,菌株P83对玉米植株促生效果比对照显著提高,玉米植株鲜重提高9.5%-89.2%、干重增加35%-231%,土壤有效磷提高2.1-40.5 mg/kg。田间小区玉米产量结果显示,溶磷菌P83增产效果最好(P=0.05),玉米子粒产量达9.2t/hm2,比不接种菌剂的对照增加2.4 t/hm2,增产率为35.3%。【结论】获得了一株溶解难溶磷的斜卧青霉菌P83,它能够活化多种难溶磷、显著增加土壤有效磷水平,对玉米生长和增加作物产量具有显著作用,是一株展现良好应用前景的高效溶磷菌种。     

贵州两处茶园溶磷青霉菌的筛选、鉴定及溶磷能力分析

为维持土壤自然完整性、活化利用土壤中难溶性磷,从贵州名茶产地都匀、贵定茶园土壤中筛选高效溶磷真菌,为制备真菌肥料提供菌种资源。利用溶磷指数(SPI)、形态特征和ITS rDNA序列筛选、鉴定菌株,并采用液体摇床培养实验测定鉴定菌株在以磷酸钙、磷酸铁或磷酸铝为唯一磷源的无机磷液体培养基中的溶磷能力。共筛选到7个高效溶磷菌落,经形态观察分属2种菌株,鉴定为微紫青霉(Penicillium janthinellum)和赭绿青霉(Penicillium ochrochloron)。液体培养基接种、摇床培养15 d,微紫青霉菌在以Ca3(PO4)2、Fe3(PO4)2或AlPO4为唯一磷源的上清液中有效磷含量分别为73.47 mg·L^-1、30.93 mg·L^-1和14.00 mg·L^-1,4℃继续保存至30d后对Fe-P和Al-P的溶解量分别达到72.20 mg·L^-1、32.84 mg·L^-1;赭绿青霉菌培养15d的溶磷量分别为30.72 mg·L^-1、4.14 mg·L^-1和1.51 mg·L^-1,30d对Fe-P和Al-P的溶解量分别达到35.19 mg·L^-1和10.98 mg·L^-1。微紫青霉菌溶解无机磷能力明显优于赭绿青霉菌,有望应用于地区缺磷茶园土壤真菌肥料的制备。     

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.     

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。     

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。     

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.     

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.     

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。     

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.     

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.     

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.