土壤中嗜酸性氧化亚铁硫杆菌的分离鉴定及其性能研究

采用改进型Leathen培养基直接从辽宁省抚顺市红透山铜矿附近的土壤中分离到了一株高度嗜酸的氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)菌株(暂命名为R2)。鉴定表明,该菌株为革兰氏阴性细菌,在扫描电镜下观察该菌株为短杆状,菌体大小为(0.4±0.2)μm×(1.6±0.4)μm。最适pH值2.0,化能自养型,能利用亚铁、单质硫和硫代硫酸钠生长,不能利用葡萄糖、蛋白胨生长。并且以16S rDNA序列同源性为基础构建了17株已报道菌种在内的系统发育树,将16S rDNA测序结果输入Genebank以Blast软件进行序列同源性比较,结果显示与氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)的多株细菌具有较高的同源性(>99%),其中与Acidithiobacillus ferrooxidans strain TGS的相似性达到100%,与标准株Acidithiobacillus ferrooxidans strain ATCC33020相似性为99.3%,结合其生理生化特性可以确定该菌为氧化亚铁硫杆菌种。序批式试验法研究表明,接种该株菌可有效溶出土壤中重金属,经过5d的生物淋滤,Cu、Cr、Zn、Cd的最高去除率分别达到30.6%、16.3%、58.4%和72%。

应用ARDRA技术研究Frankia菌多样性

应用原核生物 16SrDNA特异性引物rD1和fD1,对分自 4个分类接种群的 12株纯培养Frankia菌总DNA进行扩增 ,得到 1条长约 15 0 0bp的扩增产物。选用 2种内切酶HinfI ,MspI对扩增产物进行酶切 ,得到稳定的酶切图谱。对图谱的分析结果表明 ,Frankia菌间存在极其丰富的遗传多样性

Vertical distribution of bacterial and archaeal communities along discrete layers of a deep-sea cold sediment sample at the East Pacific Rise (similar to 13 degrees N)

The community structure and vertical distribution of prokaryotes in a deep-sea (ca. 3,191 m) cold sediment sample (ca. 43 cm long) collected at the East Pacific Rise (EPR) similar to 13 degrees N were studied with 16SrDNA-based molecular analyses. Total community DNA was extracted from each of four discrete layers EPRDS-1, -2, -3 and -4 (from top to bottom) and 16S rDNA were amplified by PCR. Cluster analysis of DGGE profiles revealed that the bacterial communities shifted sharply between EPRDS-1 and EPRDS-2 in similarity coefficient at merely 49%. Twenty-three sequences retrieved from DGGE bands fell into 11 groups based on BLAST and bootstrap analysis. The dominant groups in the bacterial communities were Chloroflexi, Gamma proteobacteria, Actinobacterium and unidentified bacteria, with their corresponding percentages varying along discrete layers. Pairwise Fst (F-statistics) values between the archaeal clone libraries indicated that the archaeal communities changed distinctly between EPRDS-2 and EPRDS-3. Sequences from the archaeal libraries were divided to eight groups. Crenarchaea Marine Group I (MGI) was prevalent in EPRDS-1 at 83%, while Uncultured Crenarchaea group II B (UCII B) abounded in EPRDS-4 at 61%. Our results revealed that the vertically stratified distribution of prokaryotic communities might be in response to the geochemical settings and suggested that the sampling area was influenced by hydrothermalism. The copresence of members related to hydrothermalism and cold deep-sea environments in the microbial community indicated that the area might be a transitional region from hydrothermal vents to cold deep-sea sediments.