Arthrobacter sp.2PR降解2-羟基吡啶动力学及降解特性研究

从辽河口石油污染土壤中筛选到一株能够以2-羟基吡啶作为唯一碳源、氮源和能源进行生长的菌株2PR,基于形态学观察、16S rRNA基因序列分析鉴定菌株2PR属于节杆菌属(Arthrobacter)。菌株2PR生长和降解2-羟基吡啶的最适条件是30℃,pH为7.0。当2-羟基吡啶初始浓度为6.0mg/ml时,120h菌株2PR对2-羟基吡啶的降解效率为94.48%,初始2-羟基吡啶浓度为8.0mg/ml时,156h的降解效率为89.21%。对2-羟基吡啶降解动力学过程进行模拟,结果显示菌株2PR生长和降解过程符合logisitic模型,该模型为环境中2-羟基吡啶的生物降解提供了理论参考。休止细胞反应和中间代谢产物检测表明,菌株2PR在降解2-羟基吡啶的过程中生成了蓝色化合物4,5,4',5'-tetrahydroxy-3,3'-diazadiphenoquinone-(2,2')。推测该菌株降解2-羟基吡啶的途径可能是首先由双加氧酶催化生成2,3,6-三羟基吡啶,后者会自发形成蓝色中间代谢产物,2,3,6-三羟基吡啶发生开环反应,最终被完全降解。菌株2PR是已报道菌株中2-羟基吡啶耐受能力和降解能力最强的菌株,在污染物生物修复方面具有广阔的应用前景。     

Conjugation in Polytomella agilis Araga˜o (Volvocida,Polyblepharidae)*

SYNOPSIS. The occurrence of conjugation in the flagellate, Polytomella agilis Aragão, as first reported in 1910, is confirmed. The gametes made contact with each other in a variety of positions. Our observations differ in minor ways from those reported for P. agilis and are in considerable disagreement with others published on sexual reproduction in Polytomella caeca.     

An assessment of the importance of heathlands as habitats for reptiles

SPELLERBERG, I. F., 1989. An assessment of the importance of heathlands as habitats for reptiles. Britain has a species-poor reptile fauna of six species. Although they occur in association with various types of plant communities, most species seem to be associated with heathlands. The lizard Lacerta agilis is particularly associated with heathlands but data presented here suggests that the vegetation structure of typical, undisturbed, lowland heathlands is less suitable for this species than disturbed heathland with more structural diversity.     

Involvement of Escherichia coli K-12 recombination functions in elimination of multicopy plasmid R6K by DNA-damaging agents

Abstract A neutral lipomannan has been isolated from the membranes of Micrococcus agilis . In contrast to the lipomannans from 2 strains of Micrococcus luteus , which contained succinic acid ranging from 5.1%–8.0%, the M. agilis lipomannan had no detectable succinyl residues and exhibited neutral behaviour on Concanavalin A-agarose rocket electrophoresis. As with the M. luteus lipomannans, mannose was the only sugar detectable (as alditol acetate) by GLC analysis in the purified M. agilis lipomannan. Fatty acids accounted for 2% of the M. agilis lipomannan and were predominantly C₁₅ branched-chain acids, with higher amounts of C₁₆ iso and C₁₇ anteiso than that found in the M. luteus polymers. Neither conditions of growth of the organism nor the method of membrane preparation appeared to be responsible for the absence of succinyl residues. This appears to be the first report of a neutral membrane amphiphile.     

Purification and properties of an endo-inulinase from an Arthrobacter sp.

Extracellular endo-inulinase of Arthrobacter sp. S37 was purified 63-fold, giving a single band on PAGE with activity staining. The Mr was estimated as 75 kDa by SDS-PAGE. The first 31 amino acids of the N-terminal sequence was determined. The endo-inulinase hydrolyzed inulin mainly into inulo-triose (F3), inulo-tetraose (F4) and inulo-pentaose (F5) optimally at pH 7.5 and 50°C. © Rapid Science Ltd. 1998     

阿特拉津降解菌Arthrobacter sp.AG1降解基因研究

菌株Arthrobacter sp. AG1能以4000mg/L的阿特拉津(AT)为唯一碳源、氮源和能源生长。通过设计特异引物从AG1中扩增出阿特拉津氯水解酶基因trzN的全序列,该基因与已报道的trzN基因序列相似性为99%。AG1菌株中含有两个大于100kb的质粒,Southern杂交结果显示trzN和atzB基因均位于其中较大的一个质粒pAG1上。将AG1菌株在LB液体培养基中转接三代后,发现34%的细菌细胞丢失了降解活性,但却未发现丢失质粒,PCR扩增结果表明突变子丢失了trzN基因,但atzB和atzC基因未丢失,说明降解活性的缺失是trzN基因片段从质粒上丢失的结果,表明trzN基因在环境中存在水平转移现象,暗示菌株AG1中的阿特拉津降解基因是基因的水平转移重组的结果。     

Plant–rhizobacteria interactions alleviate abiotic stress conditions

Root-colonizing non-pathogenic bacteria can increase plant resistance to biotic and abiotic stress factors. Bacterial inoculates have been applied as biofertilizers and can increase the effectiveness of phytoremediation. Inoculating plants with non-pathogenic bacteria can provide 'bioprotection' against biotic stresses, and some root-colonizing bacteria increase tolerance against abiotic stresses such as drought, salinity and metal toxicity. Systematic identification of bacterial strains providing cross-protection against multiple stressors would be highly valuable for agricultural production in changing environmental conditions. For bacterial cross-protection to be an effective tool, a better understanding of the underlying morphological, physiological and molecular mechanisms of bacterially mediated stress tolerance, and the phenomenon of cross-protection is critical. Beneficial bacteria-mediated plant gene expression studies under non-stress conditions or during pathogenic rhizobacteria–plant interactions are plentiful, but only few molecular studies on beneficial interactions under abiotic stress situations have been reported. Thus, here we attempt an overview of current knowledge on physiological impacts and modes of action of bacterial mitigation of abiotic stress symptoms in plants. Where available, molecular data will be provided to support physiological or morphological observations. We indicate further research avenues to enable better use of cross-protection capacities of root-colonizing non-pathogenic bacteria in agricultural production systems affected by a changing climate.     

中国盲走螨属Agilis群种类记述（蜱螨亚纲：植绥螨科）

本文新建立盲走螨属ａｇｉｌｉｓ群并限定了该群的主要特征,归纳了世界上已描述的８种,其中分布于我国的３种,此外描述了３个新种。     

一株乙内酰脲酶产生菌Arthrobacter K1108的筛选及鉴定

从沈阳市浑河地区污泥中分离得到了一株乙内酰脲酶产生菌 ,薄层色谱和氨基酸自动分析仪的分析结果表明 ,该菌的完整细胞可催化 5 -苄基乙内酰脲水解产生苯丙氨酸。对该菌进行了细菌分类学鉴定 ,确定该菌为节杆菌属的一个种 ,故命名为 Arthrobacter sp.K1 1 0 8     

Production of polysaccharides by Arthrobacter globiformis associated with Anabaena azollae in Azolla leaf cavity

Abstract The composition of the capsular polysaccharides (CPS) and exopolysaccharides (EPS) of three strains of Arthrobacter globiformis , isolated from the leaf cavities of Azolla caroliniana (strain B1), A. filiculoides (strains A3 and L1) and A. globiformis ATCC 8010 have been analysed by HPLC and enzymatic assays. Glucose and galactose were detected in the EPS of all the strains, while rhamnose was present only in the EPS of the strain L1 and uronic acids in B1 and ATCC 8010. Traces of fructose were detected by enzymatic assays in all the strains. The CPS contained glucose, galactose and rhamnose, while uronic acids were present only in strain B1. In all the strains the amount of EPS was higher than CPS. The reactivity to different dyes and lectins of the mucilagineous matrix of the algal packets extracted from the fern and of the bacterial mucilage were similar.     

不同CO2浓度下长白山3种树木幼苗的光合特性

选取长白山针叶树红松 (Pinuskoraiensis)、长白赤松 (Pinussylvestriformis)和阔叶树水曲柳(Fraxinusmandshurica)幼苗为研究对象 ,以开顶箱的方式控制CO2 浓度为 5 0 0和 70 0 μmol·mol-1,经过 3个生长季CO2 处理后 ,分别测定了 3个树种的 3年生幼苗在高浓度CO2 和大气CO2 浓度下的光合特性 .结果表明 ,前两个生长季高浓度CO2 处理增强了 3个树种幼苗的光合能力 ;不同树种在相同CO2 浓度下 ,最大净光合速率及光响应参数值不同 ;第 3个生长季 ,除 5 0 0 μmol·mol-1CO2 下生长的长白赤松外 ,各树种的幼苗在高浓度CO2 下并未发生“光合驯化”现象 ;最大净光合速率及光响应参数值随CO2 处理时间的延长有不同幅度的增减 ;高浓度CO2 改变了树木幼苗对强光和弱光的利用能力 .     

一株节杆菌溶解磷矿粉的动态

磷矿粉用量明显地影响节杆菌1TCRi7菌株对其溶解,随着磷矿粉用量的增加,溶磷率急剧下降,超过5 g/L,溶磷率不到0.1%,培养液的pH也随磷矿粉用量增加而升高,但菌体生长繁殖几乎不受磷矿粉用量的影响。振荡培养时,第1 d菌体繁殖量就达到高峰,pH也降至最低,同时表现出强烈的溶磷活力,但菌株的溶磷量并不与其生长量吻合,溶磷量第9 d才达到高峰,以后逐渐下降。培养过程中有机酸分泌发生交替变化,主要分泌乙酸和丙二酸。第1 d、第9 d和第15 d出现3个峰值,说明微生物利用了所分泌出来的有机酸,并发生了有机酸代谢的变化。     

Arthrobacter K1108乙内酰脲酶转化产物的鉴定

用 Arthrobacter sp.K1 1 0 8的完整细胞为酶源 ,对 DL- 5 -苄基乙内酰脲进行了酶法转化 ,对转化产物进行了提取和精制 ,并通过理化分析和光谱分析进行了鉴定 ,证实所得产物确实为 L-苯丙氨酸 ,同时证实 K1 1 0 8的乙内酰脲酶是 L-选择性的     

Effects of Thiamine Deprivation and Replacement on the Mitochondrion of Polytomella agilis*

SYNOPSIS. Late log-phase cells of Polytomella agilis, grown with or without thiamine, were examined by electron microscopy. The mitochondrial profiles of cells cultivated in the presence of thiamine are relatively few in number and irregular in shape. The inner membranes, randomly dispersed in a light matrix, are elongated, vesicular, or branched in appearance. In vitamin-deficient cells, numerous mitochondrial profiles are evident. They have a regular circular or ovoid appearance. The inner membranes are regularly arrayed in an electron-dense matrix and generally appear elongated. By means of partial 3-dimensional reconstruction of whole cells the appearance of mitochondrial profiles in vitamin-deficient cells can be explained by the increased branching of a single structure. Following transfer of vitamin-deficient cells to complete medium, normal mitochondrial structure is attained by ∼3 hr. Reduced-minus-oxidized difference spectra of suspensions of normal and vitamin-deficient cells, grown with gentle aeration, were recorded. The concentrations of a- and b-type cytochromes are reduced by 80-90%, and c-type cytochromes are reduced by 40% in thiamine-deficient cells.