Dissertation > Excellent graduate degree dissertation topics show

Characterization of an Atrazine-Degrading Strain, Cloning of Key Degrading Related Genes and Construction of a Gene Cluster

Author: ZuoCaiFang
Tutor: LiShunPeng;HongQing
School: Nanjing Agricultural College
Course: Microbiology
Keywords: atrazine biodegradation isolation & Characterization gene cluster GEM
CLC: X172
Type: Master's thesis
Year: 2011
Downloads: 19
Quote: 0
Read: Download Dissertation

Abstract


Atrazine is a kind of triazine herbicide, which is widely used at home and abroad, it plays an important role in the weed control. Although it has low toxity, its residue could damage subsequent crops, such as wheat, soybean and rice. So the bioremediation of the atrazine-contaminated soil has become the hot research topic in the scope of pesticide pollution control. Investigations of microbial degradation are useful in the development of strategies for bioremediation.A bacteria strain X-4 capable of degrading atrazine was isolated from atrazine-contaminated soil. It was preliminarily identified as Arthrobacte sp. according to its physical and biochemical characteristics and the analysis of its 16S rRNA gene sequence.Biological characteristics of strain X-4 was investigated and the results showed that, Strain X-4 could grow well from pH 6.0-10.0, the optimal pH for its growth was 6.0, the optional temperature for its growth was 30℃; maltose and beef extract were the best carbon source and nitrogen source its growth, respectively. The degradation rate against 100 mg·L-atrazine of strain X-4 was 95.7% within 42 h,30℃was the optimal degrading temperature. On the concentration of 1 mmol·L-1, strain X-4 was resistant to heavy metal ions, except Cu2+, Mn2+and Hg2+, which showed its potential in treating the co-contamination of atrazine and heavy metals.The primers were designed according to the published sequences of atrazine degrading related genes. The complete trzN gene of strain X-4 was cloned by PCR, it showed 100% sequence identity to that of stain C190. The conserved fragments of atzB and atzC gene were also amplified by PCR and sequenced; they showed 100% and 99% sequence identity to the reported corresponding ones respectively, which revealed that the degrading related genes of strain X-4 were the combination of trzN, atzB and atzC.On the base of plasmid pETatzA and strain X-4, complete gene of atzA, atzB and atzC were amplified by PCR and cloned to plasmid pUC18, and the expressing related elements were equipped, then the recombinant plasmid pUCatzABC with the gene cluster atzABC was constructed by combination. E.coli/pUCatzABC could transform atrazine to cyanuric acid and undertake the key catalyzing steps of the atrazine- degrading pathway, which established the foundation for the construction of atrazine-degrading genetically engineered microorganism (GEM).

Related Dissertations

  1. Studies on the Isolation of Oil-Degrading Bacteria with Biosurfactant Production and Their Characteristics,X172
  2. Isolation and Characterization of Fenoxaprop-P-Ethyl Degrading Bcteria Strain MEPE-0128 and Purification of a Fenoxaprop-P-Ethyl Hydrolase,X172
  3. Screening, Bio-Characteristics and Biopulping Application of a High Pectin-Degrading Baeterial Strain by Ultraviolet-Ray Mutation,TS713
  4. Isolation & Characterization of 3-Phenoxybenzoic Acid-Degrading Strain BA3 (Sphingobium Sp.) and Construction of Genetically Engineered Microorganism,X172
  5. The Biomechanics and Imageology Preliminary Studies of Lumbar Intertransverse Absorbable Fusion Cage in the Process of Biodegradation,R687.3
  6. The Legal Prevention of Gem Risk in China,F832.51
  7. The Correlational Study of between Characteristic of Corporate Governance Structure and Earnings Management of Gem Listed Companies,F275
  8. Associations between Single Nucleotide Polymorphisms in Nicotinic Acetylcholine Receptor Genes and DNA Damage Levels of Coke Oven Workers,R131
  9. Acclimating, Screening and Degradation Characteristics of Pentachlorophenol-degrading Bacterium,R114
  10. The Research on Chinese Delisting System of GEM,F832.51
  11. China's press and media coverage of foreign study cited only,G210
  12. Research of Market Volatility Impact in GEM China with Price Limits Policy,F224
  13. Guizhou Province landing GEM Financing SME Research,F276.3
  14. White rot fungi on PAHs adsorption and biodegradation of biological repair,X172
  15. Venture capital for innovative business performance Empirical Study,F272;F224
  16. Isophthalonitrile degrading Bacteria Screening and Degradation Mechanism,X172
  17. Heat Treatment on biodegradable PBST elastic fibers and degradation properties,TQ340.1
  18. Eat sphingosine activated sludge bacteria Degradation Mechanism of steroidal estrogens,X703
  19. 2,4 - dinitrotoluene microbial degradation studies of metabolic,X172
  20. China's GEM regulatory perfect legal system,F832.51

CLC: > Environmental science, safety science > The basic theory for the Environment and Science > Environmental Biology > Environmental Microbiology
© 2012 www.DissertationTopic.Net  Mobile