Characterization of tricalcium phosphate solubilization by Stenotrophomonas maltophilia YC isolated from phosphate mines

The phosphate solubilizing characteristics of a strain YC, which was isolated from phosphate mines (Hubei, China), were studied in National Botanical Research Institute’s phosphate (NBRIP) growth medium containing tricalcium phosphate (TCP) as sole phosphorus (P) source. The strain YC is identified as Stenotrophomonas maltophilia (S. maltophilia) based upon the results of morphologic, physiological and biochemical characteristics and 16S rRNA sequences analysis. The results show that the strain S. maltophilia YC can solubilize TCP and release soluble P in NBRIP growth medium. A positive correlation between concentration of soluble P and population of the isolate and a negative correlation between concentration of soluble P and pH in the culture medium are observed from statistical analysis results. Moreover, gluconic acid is detected in the culture medium by HPLC analysis. It indicates that the isolate can release gluconic acid during the solubilizing experiment, which causes acidification of the culture medium and then TCP solubilization. S. maltophilia YC has a maximal TCP solubilizing capability when using maltose as carbon source and ammonium nitrate as nitrogen source, respectively, in NBRIP growth medium. Foundation item: Project(2004CB619201) supported by the Major State Basic Research and Development Program of China; Project(Z200515002) supported by the Key Project Foundation of the Education Department of Hubei Province, China; Project(GCP200801) supported by the Open Research Fund of Key Laboratory for Green Chemical Process of Ministry of Education, China; Project(Q200811) supported by the Youths Science Foundation of Wuhan Institute of Technology, China     

基于16SrRNA基因的戈登氏菌演化分析

探讨19种戈登氏菌共31株间16SrRNA基因演化关系。利用16SrRNA基因序列进行相似性分析和同源性比对,并运用Neighbor．Joining法构建进化树,进行演化分析。其中13条16SrRNA基因序列来自临床分离株,其他16SrRNA基因序列来自Genbank。结果表明：13株临床分离菌株包含4株Gordoniaparaffinivorans,6株Gordoniabronchialis和3株Gordoniasputi,临床分离株的相似性百分比为93．5％-99．7％;16SrRNA基因序列在戈登氏菌不同种间存在较为明显的差异性（2％-6．2％）,可将临床分离株鉴定到种。进化分析结果显示：戈登氏菌分为两大类群,三种临床分离株在演化上按出现的先后依次为Gordoniabronchialis、Gor-doniasputi、Gordoniaparaffinivorans。所做研究可为戈登氏菌相关疾病的流行、预防、治疗和控制提供一定的参考。     

Isolation and characterization of Acidithiobacillus caldus from several typical environments in China

Six strains of moderately thermophilic sulfur-oxidizing bacteria were isolated from several different typical environments in China. The identities of the isolates were confirmed by analyses of their 16S rRNA genes, and some key physiological traits. The isolates are Gram negative, rod-shaped bacteria, their optimal temperature and pH value for growth are 45-50 ℃ and 2.5-3.5 respectively. They are autotrophic and used＇elemental sulfur, sodium thiosulfate and potassium tetrathionate as electron donor, while a little glucose stimulated their growth. 16S rDNA sequences analysis reveals that the strains are phylogenetically clustered to Acidithiobacillus caldus.     

Isolation and characterization of acidophilic bacterium from Dongxiangshan Mine in Xinjiang Province, China

One bioleaching bacterium, named as strain DXS, was isolated from acid mine drainages (AMDs) of Dongxiangshan Mine of Hami, Xinjiang Province, China. The strain DXS is gram-negative and rod-shaped with a size of (0.40±0.05) μm×(1.3±0.5) μm. The optimal temperature and pH for growth are 30 ℃ and pH 2.0, respectively. It can grow autotrophically by using ferrous iron, elemental sulfur and NaS2O3 as sole energy sources. In the phylogenetic tree, strain DXS has similarity with Acidithiobacillus ferrooxidans typ...     

Ecology detection of moderate thermophilic enrichment at Lau Basin hydrothermal vents

Culturable thermophilic microorganisms were enriched from samples collected from Lau Basin hydrothermal vents in artificial seawater medium at 45 °C and pH 7.0. Microbial diversities of the enriched communities were defined by performing a restriction fragment length polymorphism (RFLP) analysis of 16S rRNA gene sequences with enzymes MspI and Hin6 I. A total of 14 phylotypes have been detected by the RFLP patterns identified for 16S rRNA clone libraries of the enrichment. Analysis of sequences showed that ...     

Identification and fermentation optimization of protopectinase-overproducing strain Aspergillus niger CD-01 for pectin production

In order to solve the citrus peel resource waste problem and minimize the drawbacks of chemical extraction of pectin, a protopectinase-overproducing strain CD-01 for pectin production was isolated from a pit soil dumped with perished orange in Changde City, Hunan Province of China. The strain CD-01 had the same morphology and 28S rRNA gene sequence (FJ184995) as that of Aspergillus niger (ATCC 64028). It was thus identified and named as Aspergillus niger CD-01. The fermentation condition was optimized based on L₉(3⁴) orthogonal experimental design and the variances analyses. The results show that the optimal condition for producing pectin is as follows: time 36 h, temperature 35 °C, pH 5, and urea as the nitrogen source. Under this condition, the pectin yield can reach up to 24.5%. This shows a great potential of Aspergillus niger CD-01 in pectin extraction from citrus. Foundation item: Projects(50621063, 50674101) supported by the National Natural Science Foundation of China     

A novel salt-tolerant Micrococcus sp. DUT_AHX capable of degrading nitrobenzene

A novel strain of Micrococcus sp. DUT_AHX, which was isolated from the sludge of a nitrobenzene (NB)-manufacturing plant and could utilize NB as the sole carbon source, was identified on the basis of physiological and biochemical tests and 16S ribosomal DNA (rDNA) sequence analysis. It can grow at the temperature up to 40 °C or in the presence of NaCl concentration up to 12 g/L in Luria-Bertani (LB) medium. The optimal degradation conditions are as follows: temperature 37 °C, pH 7.0, and shaking speed 150 r/min. The strain involves a partial reductive pathway due to the release of ammonia and can also utilize 2-aminophenol as the sole carbon source. Furthermore, the enzyme activity tests show that crude extracts of NB-grown strain DUT_AHX mainly contain 2-aminophenol 1, 6-dioxygenase activity. The exploitation of salt-tolerant bacteria will be a remarkable improvement in NB bioremediation and wastewater treatment at high salinity and high temperature.     

西施舌16S rRNA基因片段PCR扩增及其核苷酸序列分析

利用酚/氯仿抽提法提取了西施舌闭壳肌总DNA,以总DNA为模板,利用两条16S rRNA基因特异引物,进行PCR扩增,扩增产物测序后进行序列分析。结果从西施舌的闭壳肌提取得到总DNA,获得一个长度约300 bp的PCR扩增产物;测序结果显示此片段为294 bp;核苷酸序列经WU-blast2分析,与Spisula subtruncata(AJ548774)和Corbicula sp(AY097259)的16S rRNA的同源性均为74%。经DNAStar分析,此核苷酸序列A,G,T,C含量分别为35.74%,25.51%,26.19%和13.59%,A T(61.90%)含量明显高于G C(38.10%)含量。     

Isolation and characterization of YNTC-1, a novel Alicyclobacillus sendaiensis strain

A heterotrophic acidothermophilic bacterial strain, YNTC-1, was isolated from an acidic hot spring in Tengchong, Yunan, China. YNTC-1 grows at pH value of 1.5-8.0 and temperature of 40-70 ℃, with optimal pH and temperature at 3.0 and 55 ℃, respectively. The cells of the strain are in shape of short rod, with 1.0-1.2 μm in length and 0.7-0.8 μm in diameter, and with distinct spores at both poles of each cell. The predominant fatty acids in cellular membrane of the strain are C18：1 ω7c. 16s rRNA gene analysis reveals that this strain is closely related to Alicyclobacillus sendaiensis, with over 99% sequence similarity. Based on phenotypic and genotypic analyses, YNTC-1 is identified as a member ofA. sendaiensis. Considering some important morphological and biochemical differences between strain YNTC-1 and A. sendaiensis ATCC 27009T, YNTC-1 may be proposed to be a novel subspecies of A. sendaiensis. However, this viewpoint has to be confirmed by further studies. Co-bioleaching of pyrite and chalcopyrite with strain YN22, Sulfobacillus thermosulfidooxidans, shows that strain YNTC-1 has no evident influence on bioleaching rates of these two sulphide minerals.     

Screening, identification and desilication of a silicate bacterium

The strain Lv（1- z） isolated from the Henan bauxite was characterized by morphological observation, biochemical and physiological identification, and 16S rDNA sequence analysis. The influences of temperature, initial pH value, the volume of medium, shaking speed and illite concentration on the desilicating ability of the strain Lv（1- z） were investigated. The results show that the bacterium is a Gram-negative rod-shaped bacterium with oval endspores and thick capsule, but without flagellum. The biochemical and physiological tests indicate that the strain Lv（1- z） is similar to Bacillus rnucilaginosus. In GenBank the 16S rDNA sequence similarity of the strain Lv（1- z） and the B. rnucilaginosus YNUCC0001（AY571332） is more than 99%. Based on the above results, the strain Lv（1- z） is identified as B. rnucilaginosus. The optimum conditions for the strain L（1- z） to remove silicon from illite are as follows., temperature is 30℃ ;initial pH value is 7.5; medium volume in 200 mL bottle is 60 mL; shaking speed of rotary shaker is 220 r/m ; illite concentration is 1%.     

嗜盐菌AB3中细菌视紫红质和系统发育研究

为了研究分析嗜盐古生菌物种与细菌视紫红质(BR)蛋白基因资源,分离纯化得到极端嗜盐古生菌AB3. 采用聚合酶链式反应(PCR)方法对其编码螺旋C至螺旋G的蛋白基因片断和16S rRNA基因进行了扩增,并测定了基因的核苷酸序列. 翻译出的氨基酸序列与已报道的相应片断进行对比,AB3中的螺旋C至螺旋G蛋白与其他菌株差异显著.基于BR蛋白和16S rDNA序列的同源性比较以及系统发育学研究表明,AB3是Natrinema属中的新成员. 菌株AB3的16S rDNA序列已被GenBank数据库收录,其序列号为AY277583.     

一株浸矿细菌的分离及其对低品位硫化镍铜矿中镍的浸出

从云南某铜矿井下酸性污水中分离到嗜酸菌株ynxd-1,对其形态、生长特性、16 S rRNA基因序列及其对低品位硫化镍铜矿的摇瓶浸出效果进行了研究.结果表明:细菌细胞呈短杆状,革兰氏染色阴性,不产芽孢,最适pH值及生长温度分别为2.0和30℃.菌株ynxd-1在10%(W/V)矿浆浓度及30℃温度的条件下摇瓶培养浸出28 d,低品位硫化镍铜矿镍的浸出率为56.4%.16 S rRNA基因序列分析表明,菌株ynxd-1与嗜酸氧化亚铁硫杆菌的同源性达到99%,可以鉴定为嗜酸氧化亚铁硫杆菌菌株.     

大蒜在葱科的分子分类地位研究

通过扩增获得18S rRNA和叶绿体16S rRNA基因序列,测序并提交GenBank ,登录号分别是JF719285和JF719286．利用大蒜和GenBank相关序列构建系统发育树,进行分子演化分析．结果表明：大蒜18S rRNA 基因与球序韭、韭菜、茖葱等葱科植物序列相似度高;叶绿体16S rRNA基因与龙舌兰科和薯蓣科的物种序列相似度高．大蒜与葱科植物在18S rRNA序列上具有较高的同源性．18S rRNA序列在植物演化方面的区分度比16S rRNA高．     

家蚕微孢子虫16S Rrna基因序列及分子进化

通过PCR克隆了家蚕微孢子虫（Nosema bombycis)苏州株的完整16S rRNA基因序列。序列分析表明，16S rRNA基因大小为1235bp，缺乏多个被认为是真核生物序列的区域，序列结构特征更多地类似于原核生物的，在进化上，推测微孢子虫在很早以前与原始真核生物产生分歧；分子进化分析发现，同属的微孢子虫可以处于系统进化树不同的分枝。     

Aerobic biodegradation of diethyl phthalate by Acinetobacter sp. JDC-16 isolated from river sludge

A gram negative bacterium, named JDC-16, which can grow well on the substrate of phthalic acid esters (PAEs) as the sole source of carbon and energy, was isolated from river sludge. Based on the morphology, physiological and biochemical properties and analysis of 16S rRNA gene sequence, it was preliminarily identified belonging to the genus Acinetobacter. The result of substrates utilization range indicates that strain JDC-16 can utilize a variety of phthalates except for diisononyl phthalate (DINP). The degradation tests using diethyl phthalate (DEP) as the model compound show that the optimal pH and temperature for DEP degradation by Acinetobacter sp. JDC-16 is 8.0 and 35 °C, respectively. Meanwhile, degradation kinetics under various initial concentrations of DEP reveals that substrate depletion curves fit well with the modified Gompertz model with high correlation coefficient (R ²>0.99). Furthermore, the substrate induction test indicates that DEP-induction can apparently shorten the lag phase and enhance the degradation rate. This work highlights the potential of this isolate for bioremediation of phthalates-contaminated environments.     

Microstructure and texture evolution during warm compression of the magnesium alloy AZ31

The evolution of the microstructure and texture with strain during compression at 150℃ of the magnesium alloy AZ31 has been investigated using the electron backscattered diffraction (EBSD) technique. The initial samples were chosen to have a strong basal plane texture with the crystal c-axes perpendicular to the compression direction. The EBSD data provide evidence concerning the relative activity of both {10-12} extension twinning and slip, and suggest that non-basal slip is important in samples deformed to a strain of more than 0.2. The relative contributions of the twinning and the slip during deformation have been discussed based on the results above.     

Modeling of metadynamic recrystallization kinetics after hot deformation of low-alloy steel Q345B

Based on the steady-state strain measured by single-pass hot compression tests, the method by a double-pass hot compression testing was developed to measure the metadynamic-recrystallization kinetics. The metadynamic recrystallization behavior of low-alloy steel Q345B during hot compression deformation was investigated in the temperature range of 1 000–1 100 °C, the strain rate range of 0.01–0.10 s⁻¹ and the interpass time range of 0.5–50 s on a Gleeble-3500 thermo-simulation machine. The results show that metadynamic recrystallization during the interpass time can be observed. As the deformation temperature and strain rate increase, softening caused by metadynamic recrystallization is obvious. According to the data of thermo-simulation, the metadynamic recrystallization activation energy is obtained to be Q _md=100.674 kJ/mol and metadynamic recrystallization kinetics model is set up. Finally, the error analysis of metadynamic recrystallization kinetics model proves that the model has high accuracy (correlation coefficient R=0.988 6).     

Synthesis of C3S by sol-gel technique and its features

Sol-gel method is a technique to synthesize inorganic materials based on wet-chemical reaction theory. The results have shown that reactants tetraethyl orthosilicate (TEOS) and Ca(NO₃)₂·4H₂O can form sol and gel in solution at 50–60 °C, and the cosolvents are propyl alcohol (NPA) and H₂O, the catalyst is HNO₃. This sol-gel is burned for 12 h at 1 350–1 450 °C so that the organic matter, free water (moisture) in sol-gel system are removed and a solid reaction has taken place to form the resulting product. The product has been confirmed to be C₃S by XRD, SEM and ²⁹Si MAS NMR, as well as free lime content of the product which is less than 0.2% was determined by propanetriol-ethanol-method. The analysis determined by EDXA has indicated that the n(Ca)/n(Si) ratio in corresponding to micro-region is close to theoretical value of 3:1. This resulting product is C₃S with Si sites of Q⁰ polymerization, and has higher purity and hydraulic activities at earlier age of hydration.     

Citrate-stabilized CdSe/CdS quantum dots as fluorescence probe for protein determination

A rapid, ultrasensitive and convenient fluorescence measurement technology based on the enhancement of the fluorescence intensity resulting from the interaction of functionalized CdSe/CdS quantum dots (QDs) with bovine serum albumin (BSA) was proposed. The citrate-stabilized CdSe/CdS (QDs) were synthesized by using Se powder and Na₂S as precursors instead of any pyrophoric organometallic precursors. The modified CdSe/CdS QDs are brighter and more stable against photobleaching in comparison with organic fluorophores. At pH 7.0, the fluorescence signal of CdSe/CdS is enhanced by increasing the concentration of BSA in the range of 0.1–10 μg/mL, and the low detection limit is 0.06 μg/mL. A linear relationship between the enhanced fluorescence peak intensity (ΔF) and BSA concentration (c) is established using equation ΔF=50.7c+16.4 (R=0.996 36). Results of determination for BSA in three synthetic samples are identical with the true values, and the recovery (98.9%–102.4%) and relative standard deviation (RSD, 1.8%–2.5%) are satisfactory.     

阿尔金山盐湖极端嗜盐古生菌的分离及16S rDNA序列分析

为了研究分析新疆阿尔金山国家自然保护区阿牙克库木湖嗜盐古生菌物种资源,对分离纯化到的极端嗜盐古生菌AJ2和AJ4,采用PCR方法扩增出其16S rRNA基因(16S rDNA),并测定了基因的核苷酸序列.基于16Sr DNA序列的同源性比较和系统发育学分析,发现菌株AJ2是Natrmema属中一个与其他成员不同的新种,命名为Natrinema ajinwuensis sp.nov.;菌株AJ4是Haloarcula属中成员argentinensis的一个亚种,取名为Haloar-cula argentinensis subsp.ajinwuensis.菌株AJ2和AJ4的16S rDNA序列已被GenBank数据库收录,其序列号分别为AY208972和AY208973.