Biological characters and rDNA ITS sequences of pathogen of poplar leaf blight

DNA was extracted from the strain of pathogen of poplar leaf blight using a modified CTAB method. ITS sequence （601bp） was initially amplified from the pathogen by using the universal primers ITSl and ITS4 （registered No, DQ011257）. Comparing to the nucleotide sequences acquired from GenBank database, the strain is clustered into the homogeneity with Alternaria alternate （AY787684） and Alternaria alternate （AY354228）, with a homology of 98%, thus the strain was checked as Alternaria alternata （Fr.） Keissler. The optimal conditions for conidia germination and mycelium growth of the pathogen were tested, The optimal temperature for conidia germinating and mycelium growth is 25℃, and the optimal pH value is 6. Mycelium grows rather slowly at 10℃ and 30℃ and growth stops at above 35 ℃. Among the six culture mediums tested, PDA ＋ poplar leaf juice medium is most favorable for mycelium growth.

Association between childhood obesity and gut microbiota:16S rRNA gene sequencing-based cohort study

BACKGROUND This study aimed to identify characteristic gut genera in obese and normal-weight children(8-12 years old)using 16S rDNA sequencing.The research aimed to provide insights for mechanistic studies and prevention strategies for childhood obesity.Thirty normal-weight and thirty age-and sex-matched obese children were included.Questionnaires and body measurements were collected,and fecal samples underwent 16S rDNA sequencing.Significant differences in body mass index(BMI)and body-fat percentage were observed between the groups.Analysis of gut microbiota diversity revealed lowerα-diversity in obese children.Differences in gut microbiota composition were found between the two groups.Prevotella and Firmicutes were more abundant in the obese group,while Bacteroides and Sanguibacteroides were more prevalent in the control group.AIM To identify the characteristic gut genera in obese and normal-weight children(8-12-year-old)using 16S rDNA sequencing,and provide a basis for subsequent mechanistic studies and prevention strategies for childhood obesity.METHODS Thirty each normal-weight,1:1 matched for age and sex,and obese children,with an obese status from 2020 to 2022,were included in the control and obese groups,respectively.Basic information was collected through questionnaires and body measurements were obtained from both obese and normal-weight children.Fecal samples were collected from both groups and subjected to 16S rDNA sequencing using an Illumina MiSeq sequencing platform for gut microbiota diversity analysis.RESULTS Significant differences in BMI and body-fat percentage were observed between the two groups.The Ace and Chao1 indices were significantly lower in the obese group than those in the control group,whereas differences were not significant in the Shannon and Simpson indices.Kruskal-Wallis tests indicated significant differences in unweighted and weighted UniFrac distances between the gut microbiota of normal-weight and obese children(P<0.01),suggesting substantial disparities in both the species and quantity of gut microbiota between the two groups.Prevotella,Firmicutes,Bacteroides,and Sanguibacteroides were more abundant in the obese and control groups,respectively.Heatmap results demonstrated significant differences in the gut microbiota composition between obese and normal-weight children.CONCLUSION Obese children exhibited lowerα-diversity in their gut microbiota than did the normal-weight children.Significant differences were observed in the composition of gut microbiota between obese and normal-weight children.

Isolation and identification of a sulfate reducing bacteria and sequence analysis of its dissimilatory sulfite reductase gene

A sulfate reducing bacteria was isolated from mining sewage of Daqing Oilfield by Hungate anaerobic technology. Physiological-biochemical analysis showed that the strain could utilize polyacrylamide as sole carbon and nitrogen source. The sequence analysis of 16S rDNA illustrated that the similarity of F8 and Desulfovibrio desulfuricans (AF192153) was 99%, and the similarity sequence of dissimilatory sulfite reductase gene (DSR) cloned from the strain and Desulfovibrio desulfuricans (AF273034) was 98%. Their phylogenitic analysis was basically anastomosed, and thus temporarily named as Desulfovibrio desulfuricans F8. The DSR cloned from F8 strain was 2740 bp in length consisting of three ORF, DSRA, DSRB and DSRD as a single operon (DSRABD) regulated by the same operator. DSRA contained typical conservative box of sulfate—sulfite reducing enzyme (SiteⅠand SiteⅡ), which could bind siroheme and [Fe4S4]. DSRB retained a [Fe4S4] binding site, with an uncomplimentary structure for siroheme binding. There was no conservative box in DSRD. Sequence analysis of DSR will provide a theoretical basis for quantitative detection, metabolic pathway modification through gene engineering, and sulfate reducing bacteria (SRB) suppression.

rDNA Sequencing and Preliminary Analysis of Microorganisms from Diseased Edible Fungus Using Non-culture Technology

The metagenomic DNA of disease tissue samples from four kinds of major edible fungus was extracted by CTAB method combined with DNA gel recovery kit. The genomie DNA was amplified by polymerase chain reaction using the universal primers of 16S rDNA and 18S rDNA, and then mone, elonal sequenced after ligated and transformed, rDNA sequences of 20 positive clones were selected randomly from each pair of primers for sequence alignment. The results showed that there were two bacterial diseases and two fungul diseases in the samples, respectively.

Application of 16S rDNA Sequencing Technology in the Analysis of Pathogenic Bacteria in Sputum of Severe Pneumonia

The diagnosis of pathogenic bacteria in severe pneumonia is difficult and the prognosis is poor. Its outcome is closely related to bacterial pathogenicity and the timeliness and pertinence of antibiotic treatment. Therefore, early diagnosis is of great significance to the prognosis of patients. Sputum examination and culture is the gold standard for the diagnosis of pathogens of severe pneumonia. However, due to the long time of bacterial culture, the early use of antibiotics, the change of bacteria species, mixed infection and other problems, the results of bacterial culture in sputum are often false negative. With the continuous application of new molecular biology techniques in clinical detection, the classification of bacteria and microorganisms has deepened from the identification of phenotypic characteristics to the classification of gene characteristics. Sequencing analysis with 16S rDNA sequencing technology has the characteristics of high sequencing flux, large amount of data obtained, short cycle, and can more comprehensively reflect the species composition of microbial community, real species distribution and abundance information. In this paper, 16S rDNA sequencing technology was used to analyze the bacterial population composition in the sputum of severe pneumonia, and to explore a new method of etiological diagnosis.

Application of 16s rDNA Sequencing in the Analysis of Pathogenic Bacteria in Sputum of Severe Bacterial Pneumonia

Objective: 120 patients with severe pneumonia who were kept in the comprehensive ICU of our hospital in 2018 were selected, and 16s rDNA sequencing was performed to analyze the composition of pathogenic bacteria in the sputum of severe pneumonia. Methods: The sputum samples of patients with severe bacterial pneumonia were collected, and the diversity of pathogens in the samples was analyzed by polymerase chain reaction (PCR) amplification and high-throughput sequencing (16s rDNA PCR-DGGE). Results: Sequence showed that sputum samples contained a relatively large number of species, and there were many species that were not detected by sequencing. The dominant bacteria were Streptococcus, Sphingomonas, Corynebacterium, Denatobacteria, Aquobacteria, Acinetobacteria, Prevotella, Klebsiella, Pseudomonas, etc. Conclusion: Bacteria caused by sputum of severe bacterial pneumonia are complex and diverse, which provides new methods and ideas for individualized treatment of patients with severe pneumonia.

Phyllosphere eukaryotic microalgal communities in rainforests:Drivers and diversity

Phyllosphere algae are common in tropical rainforests,forming visible biofilms or spots on plant leaf surfaces.However,knowledge of phyllosphere algal diversity and the environmental factors that drive that diversity is limited.The aim of this study is to identify the environmental factors that drive phyllosphere algal community composition and diversity in rainforests.For this purpose,we used single molecule real-time sequencing of full-length 18S rDNA to characterize the composition of phyllosphere microalgal communities growing on four host tree species(Ficus tikoua,Caryota mitis,Arenga pinnata,and Musa acuminata) common to three types of forest over four months at the Xishuangbanna Tropical Botanical Garden,Yunnan Province,China.Environmental 18S rDNA sequences revealed that the green algae orders Watanabeales and Trentepohliales were dominant in almost all algal communities and that phyllosphere algal species richness and biomass were lower in planted forest than in primeval and reserve rainforest.In addition,algal community composition differed significantly between planted forest and primeval rainforest.We also found that algal communities were affected by soluble reactive phosphorous,total nitrogen,and ammonium contents.Our findings indicate that algal community structure is significantly related to forest type and host tree species.Furthermore,this study is the first to identify environmental factors that affect phyllosphere algal communities,significantly contributing to future taxonomic research,especially for the green algae orders Watanabeales and Trentepohliales.This research also serves as an important reference for molecular diversity analysis of algae in other specific habitats,such as epiphytic algae and soil algae.

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.

Mrakia psychrophila sp.nov.,a new species isolated from Antarctic soil

The yeast strain （Y18） was isolated from a soil sample collected from Fildes Peninsula, Antarctica. The strain is a psychrophilic yeast with optimum and maximum growth temperatures of 10 ℃ and 18 ℃, respectively. Teliospores were formed after 7 d on malt agar, when the germination of teliospores was observed. Both inositol and D-glucuronate were assimilated. Positive results of the DBB （diazonium blue B） color reaction, urease test, and starch formation were observed. The major CoQ is Qs. All results indicated that Y18 belongs to the genes of Mrakia. The 18S rDNA sequence analyses showed that Y18 is closely related to Mrakiafrigida. DNA-DNA relatedness study, and some biochemistry characteristics indicated that Y18 represents a new species for which Mrakia psychrophila sp. nov. is proposed.

The molecular biological characterization of a strain of biohydrogen-producing anaerobe in Clostridium Genus

The anaerobic process of biohydrogen production was developed recently. The isolation and identification of biohydrogen producing anaerobic bacteria with high evolution rate and yield is an important foundation of the fermented biohydrogen production process through which anaerobic bacteria digest organic wastewater. By considering physiological and biochemical traits, morphological characteristics and a 16S rDNA sequence, the isolated Rennanqilyf33 is shown to be a new species.

Mycosphaerella areola—The Teleomorph of Ramularia areola of Cotton in Brazil, and Its Epidemiological Significance

While Ramularia leaf blight of cotton caused by Ramularia areola is of top most importance for Brazil, information is lacking regarding the survival mechanism of this pathogen during the cotton-free period. The teleomorph of R. areola is expected to belong to the genus Mycosphaerella. In the present study attempts were made to verify occurrence of this teleomorph in the State of Mato Grosso, Brazil. Decaying cotton leaves were collected two months after harvest of 2014 from 44 commercial and experimental fields where aerial fungicidal applications were made or not during the crop cycle to control the Ramularia leaf blight. Examination of the decaying cotton leaves revealed presence of abundant sclerotia, spermagonia and ascoma of Mycosphaerella sp. intermingled with each other during the cotton-free period in most of the leaf samples. Mono-ascospore isolations were obtained from the ascoma and considering their cultural, morphological, pathological and DNA sequence analysis they were identified as Mycosphaerella areola. M. areola and R. areola isolates produced similar symptoms under glasshouse inoculations. Reisolation of the pathogen from the symptoms produced by M. areola isolates yielded R. areola. Some cotton leaves showing such symptoms were kept on the soil surface on plastic trays for two months under natural field condition. After this period the decaying leaves showed abundant perithecia identical to their original M. areola. ITS rDNA sequence analyses revealed identical sequences from M. areola and R. areola isolates. Occurrence and the viability of the perfect stage M. areola during the cotton-free period on the left-over stubble from one season to another were interpreted as the survival mechanism of the pathogen and were considered responsible for the Ramularia blight epidemics in the State of Mato Grosso. Disease management practices for the State of Mato Grosso are discussed. This is the first report about the occurrence of the M. areola in Brazil.

Co-monitoring bacterial and dinoflagellates communities by denaturing gradient gel electrophoresis (DGGE) and SSU rRNA sequencing during a dinoflagellates bloom

Dinoflagellates are unicellular eukaryotic protists that dominate in all coastal waters, and are also present in oceanic waters. Despite the central importance of dinoflagellates in global primary production, the relationship between dinoflagellates and bacteria are still poorly understood. In order to understand the ecological interaction between bacterial and dinoflagellates communities, denaturing gradient gel electrophoresis (DGGE) and SSU rRNA sequencing were applied to monitoring the population dynamics of bacteria and dinoflagellates from the onset to disappearance of a dinoflagellates bloom occurred in Baltimore Inner Harbor, from April 15 to 24,2002. Although Prorocentrum minimum was the major bloom forming species under the light microscopy, DGGE method with dinoflagellate specific primers demonstrated that Prorocentrum micans, Gymnodinium galatheanum and Gyrodinium uncatenum were also present during the bloom. Population shifts among the minor dinoflagellate groups were observed. DGGE of PCR-amplified 16S rRNA gene fragments indicated that cyanobacteria, α, β, γ-proteobacteria, Flavobacterium Bacteroides-Cytophaga (FBC), and Planctomcetes were the major components of bacterial assemblages during the bloom. DGGE analysis showed that Cytophagales and α-proteobacteria played important roles at different stages of dinoflagellates bloom. DGGE can be used as a rapid tool to simultaneously monitor population dynamics of both bacterial and dinoflagellates communities in aquatic environments, which is demonstrated here.

Effect of Lycopus lucidus Turcz.supplementation on gut microflora and short chain fatty acid composition in Crj:CD-1 mice

We investigated the diversity and composition of microflora in feces of Lycopus lucidus Turcz.-fed mice.In addition,we evaluated the production of major cytokines(Interleukin-6 and-10)which are related to inflammation and fatty acid composition of several tissues.16S ribosomal DNA sequencing-based microbiome taxonomic profiling analysis was performed utilizing the EzBioCloud data base.Male mice fed on L.lucidus showed a significantly reduced number of lactic acid bacteria and coliform in the feces compared with the control group(p<0.05).16S rDNA sequencing analysis of fecal samples showed that L.lucidus supplementation decreased the community of harmful microflora(Enterobacteriaceae including Escherichia coli and Bacteroides sp.)in feces compared with the control group(p<0.05).There were no significant differences in mRNA expression of cytokine IL-6 and IL-10 between the control and L.lucidus fed groups.The fecal fatty acid composition in the L.lucidus group had percentages of 4:0,6:0,8:0 and 10:0 in the intestine but those short chain fatty acids were not detected in the control group.Our results showed that L.lucidus supplementation influenced gut environment by decreasing harmful microflora and increased the percentages of several short fatty acids.

Structural and functional characteristics of microbiota in oropharynx of sub-healthy children with gastrointestinal heat retention syndrome differentiated by traditional Chinese medicine

Objective:To explore the structural and functional characteristics of microbiota in oropharynx of subhealthy children with gastrointestinal heat retention syndrome(GHRS)differentiated by traditional Chinese medicine,and screen the biometric operational taxonomic units(OTUs)to assist the clinical diagnosis.Methods:We recruited children according to the“GHRS diagnostic scale”,collected their oropharyngeal swabs,and sequenced the 16 SrDNA V4 region.We described the bacterial structure with alpha-indexes,beta-distances,and relative abundances;moreover,we screened the differential genera/OTUs with Wilcoxon rank-sum test,Metagenome Seq analysis,and linear discriminant analysis effect size(LEf Se)analysis,in which biometric OTUs were selected to construct the receiver operating characteristic curve to verify the diagnostic value.The bacterial function was predicted with Kyoto Encyclopedia of Genes and Genomes pathways according to 16S rDNA gene by using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States.Results:The study population was composed of 10 children with GHRS and 10 healthy control children.GHRS children were more likely to overeat(gluttony,P=.033).Alpha-indexes,such as Sobs,abundancebased coverage estimator,Bootstrap,and Qstat,were significantly higher in the GHRS group,while betadistances did not exhibit any significant intergroup differences.There were 9 differently distributed nonpredominant genera between the groups in Wilcoxon rank-sum test,as well as 13 non-predominant genera in Metagenome Seq analysis and 3 non-predominant OTUs in LEfSe analysis.OTU44 and OTU196 were used to construct the receiver operating characteristic curve,and the area under curve was 0.92.Predicted functions showed that pathways related to oxidative phosphorylation and carbon metabolism were enriched in healthy control samples,while the pathway related to renin secretion was remarkably enriched in GHRS samples.Conclusion:Unique oropharyngeal microbial structure and function were identified in GHRS children.OTU44 and OTU196 were specific OTUs,which could be used as biomarkers of GHRS to assist clinical diagnosis.

Isolation and Genetic Analysis of Halophilous Bacteria from Marine Sediment Collected at Tianjin Port, China

[Objective] Marine sediment from Tianjin Port has a extremely high salinity.The bacteria which live in such habitats have evolved distinct physiological,metabolic,and morphological characteristics to survive.The objective of this study is to identify all the specific salt-tolerant characteristics and the genetic evolution of the bacteria in the sediment.[Methods] In this study,the total DNA of sediment from Tianjin Port was extracted,and 16S rDNA was used to conduct an analysis of the fauna of sediment bacteria. We also isolated sediment bacteria using beef extract-peptone media with seven different NaCl concentrations (0,0.5%,2%,5%,10%,15%,and 20%),aiming to analyze the dominant species of halophilous bacteria under different salinities.[Results] 1) With each stepwise increase of salinity from 0.5% to 20%,the total number of isolated bacterial colonies decreased.14 strains of bacteria were identified and classified by the16S rDNA sequencing analysis.Of these,four could tolerate 0~2% salinity,four could tolerate 0~5% salinity,one could tolerate 0~15% salinity,and one tolerated within the full 0~20% salinity range.Further four strains were only able to tolerate within a few narrow salinity ranges.such as 5%~10%,10%~15%,10%~20% and 15%~20%;2) The quantity of bacteria strains that can be isolated from the marine sediment decreased with the increase of salinity. Also, the Shannon wiener index and species richness index of marine sediment bacteria decreased significantly from 5% salinity.However,there were no significant differences in the species evenness index;3) When the salinity was 0~10%,the dominant species was Bacillus.When the salinity was 15%, Halomonas was the dominant species.When the salinity was 20%,there were no significant differences in the proportions of these species.[Conclusion] Our results showed that some bacteria could tolerate living conditions with high salinity,and we even found a species which can tolerate a wide range of salinities (0~20%).In further study,it would be valuable to analyze these bacteria's unique physiological and biochemical functions that allow them to adapt to environments with high salinity.It can provide theories to promote the development of microbial population resources in marine sediment and the reclaimation of salinized soil by salt tolerant microorganisms.

Partial function prediction of sulfate-reducing bacterial community from the rhizospheres of two typical coastal wetland plants in China

Sulfate-reducing bacteria(SRB)are ubiquitous anaerobic microorganisms that play signifi cant roles in the global biogeochemical cycle.Coastal wetlands,one of the major habitats of SRB,exhibit high sulfate-reducing activity and thus play signifi cant roles in organic carbon remineralization,benthic geochemical action,and plant-microbe interactions.Recent studies have provided credible evidence that the functional rather than the taxonomic composition of microbes responds more closely to environmental factors.Therefore,in this study,functional gene prediction based on PacBio single molecular real-time sequencing of 16S rDNA was applied to determine the sulfate-reducing and organic substrate-decomposing activities of SRB in the rhizospheres of two typical coastal wetland plants in North and South China:Zostera japonica and Scirpus mariqueter.To this end,some physicochemical characteristics of the sediments as well as the phylogenetic structure,community composition,diversity,and proportions of several functional genes of the SRB in the two plant rhizospheres were analyzed.The Z.japonic a meadow had a higher dissimilatory sulfate reduction capability than the S.mariqueter-comprising saltmarsh,owing to its larger proportion of SRB in the microbial community,larger proportions of functional genes involved in dissimilatory sulfate reduction,and the stronger ability of the SRB to degrade organic substrates completely.This study confi rmed the feasibility of applying microbial community function prediction in research on the metabolic features of SRB,which will be helpful for gaining new knowledge of the biogeochemical and ecological roles of these bacteria in coastal wetlands.

Characterization of Fe(Ⅲ)-Reducing Enrichment Cultures and Isolation of Enterobacter sp. Nan-1 from the Deep-Sea Sediment, South China Sea

To characterize the Fe(III)-reducing bacteria,enrichment cultures were initiated by inoculating deep-sea sediment from the South China Sea(SCS)into the media with hydrous ferric oxide(HFO)as the sole electron acceptor.As indicated by Meta 16S rDNA Amplicon Sequencing,the microorganisms related to Fe(III)-reduction in the enrichment cultures were mainly Shewanella and Enterobacter.A new facultative Fe(III)-reducing bacterium was obtained and identified as Enterobacter sp.Nan-1 based on its 16S rRNA gene sequence and physiological characterizations.Enterobacter sp.Nan-1 was not only a mesophilic bacterium capable of reducing HFO with a wide range of salinity(4,34,40,50 and 60 g L−1)efficiently,but also a piezotolerant bacterium that can proceed Fe(III)-reduction sustainedly at hydrostatic pressures between 0.1 and 50 MPa using glucose and pyruvate as carbon source.Furthermore,the geochemical characteristics of deep-sea sediment indicated that the microbial metabolism and iron reduction both remain active in the well-developed Fe(III)-reducing zone where the strain Nan-1 was obtained.To our knowledge,Enterobacter sp.Nan-1 could serve as a new applicative Fe(III)-reducing bacterium for future investigation on the iron biogeochemical cycle and diagenetic process of organic matter in the deep-sea environment.

ON THE BIOSYSTEMATICS OF ANOPHELES DIRUS COMPLEX (DIPTERA:CULICIDAE) IN CHINA

Anopheles dirus complex is a major malaria vector in Southeast Asia and South China.But the role played by different member of the species complex in malaria transmission is not clearly known. Correct identification of the sibling species is a foundational requirament for working out a sound scheme in mosquito biosystematics. This paper reports the resuets of biosystematic studies on the chromosomal karyotype, egg microstructure, ribosomal DNA sequences of a second internal transcribed spacer region and polymerase chain reactions of the complex in China. Specimens of species A and D from Hainan and Yunnan Provinces were carefully analyzed and the importance of development aspect of the mosquito biosystematics in malaria control is discussed.

Screening and performance of L-14, a novel, highly efficient and low temperature-resistant cellulose-degrading strain

In view of the low bioconversion efficiency of agricultural biomass waste in low-temperature environments in winter,a low-temperature-resistant cellulose-degrading strain,L-14,was successfully screened by restrictive cultures from humus-rich soil in the Daqing Zhalong wetland region.According to morphological observations and 18S rDNA sequence analysis,the cellulose-degrading strain L-14 was identified as a Neurospora sp,belonging to fungus.Different parameters,such as temperature,initial pH,carbon,nitrogen and lecithin,were optimized using a single-factor experiment and a response surface methodology(RSM).When the temperature was 16°C,the optimal conditions for enzyme production were an initial pH 8.20,10.45 g/L of bran,5.28 g/L of yeast powder,and 4.25 g/L of lecithin.The carboxymethyl cellulase(CMCase)activity of strain L-14 was 63.598 IU/mL.Strain L-14 had a high level of cellulose degradation activity,excellent resistance to low temperatures and environmental adaptability,indicating its good application prospects in substrates pretreatment of biogas engineering.

Bioleaching of spent Ni-Cd batteries and phylogenetic analysis of an acidophilic strain in acidified sludge

Biohydrometallurgy is a novel method to recycle discarded batteries,in which sewage sludge is used as microorganisms and culture due to the presence of indigenous Thiobacilli.A two-step continuous flow leaching system consisting of an acidifying reactor and a leaching reactor was introduced to achieve the bioleaching of spent nickel-cadmium(Ni-Cd)batteries.The acid supernatant produced in the acidifying reactor by the microorganisms with ferrous ions as the substrate was conducted into the leaching reactor to dissolve electrode materials.The efficiency of a batch treatment of batteries was examined.The results showed that the complete dissolution of two AA-sized Ni-Cd batteries with 0.6 L/d acid supernatant took about 30,20,and 35 days for Ni,Cd,and Co,respectively.But the dissolution ability of the three metals was different.Cd and Co can be leached mostly for pH below 4.0 while the complete dissolution of Ni can be achieved for pH below 2.5.Meanwhile,a strain(named Thiooxidans.WL)accounting for the reduction of pH in the acidified sludge was isolated and sequenced.It was identified to be 100%similar to Acidithiobacillus ferrooxidans strain Tf-49 based on 16S rDNA sequence analysis.The relevant phylogenetic tree constructed indicates that the strain should be classified into genus Acidithiobacillus ferrooxidans.