脑栓通对脑缺血大鼠脑组织SOD活性及血清NO的影响

目的：观察脑栓通对脑缺血大鼠脑组织SOD活性及血NO的影响,以探讨脑栓通的作用机制。方法：将大鼠分为假手术组、脑缺血组和给药组。给药组大鼠每日腹腔注射脑栓通提取液1ml,7d,对脑缺血组和给药组大鼠分离并结扎两侧颈总动脉,再灌注后测定脑组织SOD及血清NO。结果：给药组大鼠脑组织SOD值升高与缺血组比较P＜0.01;血清NO值降低与缺血组比较P＜0.01。结论：脑栓通有显著改善脑部组织代谢,减慢因脑缺血而臻脑细胞损伤的作用。     

酪氨酸对海拔3700m高原人体运动自由基代谢的影响

目的：探讨酪氨酸对高原人体运动时自由基代谢的影响。方法：对进驻海拔3700m高原半年的30名健康青年,每组10人。在安静时,服药前、服药第不同时间分别进行渐增负荷运动至力竭,测定其血清中超氧化物岐化酶(SOD)、谷胱苷肽过氧化物酶(GSH-Px)和丙二醛(MDA)含量。结果：给予酪氨酸、乙酰哇胺10d即可使SOD、GSH-Px活性增强,MDA降低;乙酰哇胺停药10d药效消失,酪氨酸停药20d药效消失。结论：酪氨酸、乙酰哇胺对高原低氧所致自由基代谢失衡有调节作用,且酪氨酸效果更明显。     

Arthrobacter wenxiniae sp. nov., a novel plant growth-promoting rhizobacteria species harbouring a carotenoids biosynthetic gene cluster

A bacterial strain, designated AETb3-4^T was isolated from the rhizosphere of lily. Comparison of 16S rRNA gene sequences showed that the sequence from strain AETb3-4^T exhibits high sequence similarity with those of Arthrobacter silviterrae KIS14-16^T (97.9%), Arthrobacter livingstonensis LI2^T (97.2%) and Arthrobacter stackebrandtii CCM 2783^T (97.0%). Whole genome average nucleotide identity (ANI) and the digital DNA-DNA hybridization (dDDH) values between strain AETb3-4T and the reference strains A. silviterrae DSM 27180^T, A. livingstonensis L12^T and A. stackebrandtii DSM 16005^T were below 83.6% and 27.7%, respectively, values which are considerably below the proposed thresholds for the species delineation, consistent with the proposal that strain AETb3-4^T represents a novel species. The genome size of strain AETb3-4^T is 4.33 Mb and the genomic DNA G?+?C content is 67.3%. The main polar lipids were identified as phosphatidylglycerol, diphosphatidylglycero, phosphatidylinositol and an unidentified glycolipid. The major fatty acids (>?10%) were identified as anteiso-C_{15: 0} and anteiso-C_{17: 0}. The predominant menaquinone was found to be menaquinone 9 (MK-9) (H₂) (82.2%). Phenotypic tests allowed the strain to be differentiated from its close phylogenetic neighbors. Based on the results obtained, it is proposed that the strain AETb3-4^T (=?CFCC 16390^T?=?LMG 31708^T) represents a novel species in the genus Arthrobacter, for which the names Arthrobacter wenxiniae sp. nov. is proposed. In addition, the novel strain AETb3-4^T has multiple plant growth-promoting characters including ACC-deaminase activity and production of IAA. Furthermore, the genome contains secondary metabolite biosynthesis gene clusters, including a carotenoid biosynthetic gene cluster, suggesting potential capacities for secondary metabolite synthesis. These data suggest that strain AETb3-4^T may have potential applications both in medicine and sustainable agriculture.

     

土壤生物消毒对甘肃省中部沿黄灌区马铃薯连作障碍的防控效果

采用有机物料添加、土壤灌水和表土覆盖相结合的土壤生物消毒方法来防控甘肃省中部沿黄灌区马铃薯连作障碍,系统性地评估生物消毒对连作马铃薯块茎产量、植株生长发育及土传病害抑制、微生物区系和酶活性等土壤生化性质的影响.结果表明:生物消毒处理比对照块茎产量和植株生物量分别显著增加16.1%和30.8%,植株发病率和病薯率分别下降68.0%和46.7%.生物消毒处理显著提高了连作马铃薯叶绿素含量和主茎分枝数,改善了根系形态结构.在播前土壤生物消毒处理过程中,土壤p H值和细菌/真菌显著增加,真菌和镰刀菌数量大幅度下降,而细菌和放线菌数量则变化不明显.在马铃薯各生育时期,生物消毒处理土壤真菌数量均远低于对照,镰刀菌数量也低于对照,但随着生育进程的推进,镰刀菌数量呈现逐渐回升的趋势.无论是在生物消毒处理过程中还是马铃薯整个生育期,生物消毒处理的土壤相关酶活性与对照相比变化均不明显.总体上,土壤生物消毒的方法在克服马铃薯连作障碍上具有较大的应用潜力.     

高产番茄红素链霉菌选育及摇瓶发酵研究

番茄红素的抗氧化能力目前在类胡萝卜素中最强,是近年来国际上功能食品成分研究的热点。在国内首次利用龟裂链霉菌（Streptomyces rimosus）发酵生产番茄红素,建立了分光光度计法和HPLC法等番茄红素测定方法;以一株龟裂链霉菌Fc作为出发菌株,进行紫外诱变,筛选到一株突变高产菌株Fc’,其番茄红素产量较出发菌株提高2.5倍;通过摇瓶发酵实验优化培养条件,使菌株Fc’的番茄红素产量达到230 mg/L,并且在不添加任何阻断剂的情况下,利用链霉菌发酵可获得纯度较高的番茄红素。该结果为今后利用链霉菌工业化生产番茄红素奠定了良好基础。     

不同氮源对球形棕囊藻生长的影响

采用实验室培养的方法比较了6种不同氮源-硝态氮、尿素、甘氨酸、精氨酸、谷氨酸、腺嘌呤对典型赤潮藻球形棕囊藻(Phaeocystis globosa)生长的影响。结果表明,6种氮源均能不同程度地促进球形棕囊藻的生长,但比生长速率和光合作用效率具有显著差异性。将球形棕囊藻在不同浓度氮源下的最大比生长速率分别拟合Monod方程,得出球形棕囊藻在硝态氮、尿素、甘氨酸、精氨酸、谷氨酸和腺嘌呤等6种氮源下的最大比生长率分别为1.05,1.17,0.82,0.87,1.09,0.90d^-1,相应的半饱和常数分别为9.132,23.758,85.519,7.104,23.94,10.959μmol/L。其中,高氮浓度(8820μmol/L)下腺嘌呤对球型棕囊藻的生长具有显著抑制作用。相比较而言,球形棕囊藻对甘氨酸的亲和力最高。当硝态氮、尿素、甘氨酸、精氨酸、谷氨酸和腺嘌呤的浓度分别为8820,882,882,8820,882,0.441μmol/L时,球形棕囊藻的最大光合效率(Fv/Fm)分别为0.619,0.620,0.579,0.595,0.648,0.667。由此可见,氮源对球形棕囊藻的生长和光合作用具有显著影响;球形棕囊藻能够利用多种无机和有机氮源,与其它仅能利用无机氮源的浮游植物相比,更具有竞争优势。     

黄土高原西部旱农区不同品种马铃薯集雨限灌效应

通过大田试验研究了集雨限灌对同薯23号和大西洋两个马铃薯品种的补灌效应.结果表明：集蓄雨水在苗期补灌能显著提高旱作马铃薯的产量,且大西洋增产幅度高于同薯23号;在薯块膨大期补灌同薯23号的产量增加不显著,而大西洋减产.低额补灌（补灌45 mm）有利于同薯23号水分利用效率（WUE）和灌水利用效率（IWUE）的提高.大西洋苗期补灌的WUE和IWUE均高于薯块膨大期.补灌提高了同薯23号的大薯率、中薯率和单株薯产量,降低了小薯率, 但绿薯率、烂薯率有所增加;大西洋的大薯率和小薯率增加,中薯率稍有下降,烂薯率增加.     

Correction to: Arthrobacter wenxiniae sp. nov., a novel plant growth-promoting rhizobacteria species harbouring a carotenoids biosynthetic gene cluster

Antonie van Leeuwenhoek -     

斜茎黄芪根瘤菌结瘤基因nodA PCR扩增及PCR-RFLP分析

对采自我国北方地区的16株斜茎黄芪根瘤菌代表菌株的共同结瘤基因nodA进行了PCR扩增及PCR-RFLP分析研究。来自Mesorhizobium和Rhizobium系统发育分支的代表菌株都得到了nodA PCR扩增产物;而来自Agrobacterium系统发育分支的代表菌株都没有得到nodA PCR扩增产物。进一步的nodAPCR-RFLP分析结果表明斜茎黄芪根瘤菌具有很大的nodA基因遗传多样性,具有4种不同的16S rDNAPCR-RFLP遗传图谱类型的12株斜茎黄芪根瘤菌具有8种不同的nodA PCR-RFLP遗传图谱类型。但是斜茎黄芪根瘤菌nodA基因遗传多样性随种群而变化,来自M.septentrionale的具有相同的16S rDNA PCR-RFLP遗传图谱类型的4个代表菌株具有4种不同的nodA PCR-RFLP遗传图谱类型;而来自M.tempera-tum的具有相同的16S rDNA PCR-RFLP遗传图谱类型3个代表菌株则具有相同的nodA PCR-RFLP遗传图谱类型。此外,来自不同种的具有不同16S rDNA PCR-RFLP遗传图谱类型的菌株却具有相同的nodA PCR-RFLP遗传图谱类型,说明nodA基因可能在根瘤菌的不同种间发生了水平转移。