US EPA

1579238 

Journal Article 

Construction of small plasmid vectors for use in genetic improvement of the extremely acidophilic Acidithiobacillus caldus 

Meng, J; Wang, H; Liu, X; Lin, J; Pang, X; Lin, J 

2013 

0 

Microbiological Research
ISSN: 0944-5013 

Elsevier 

168 

8 

469-476 

English 

23639949 

10.1016/j.micres.2013.04.003 

WOS:000323095300001 

https://linkinghub.elsevier.com/retrieve/pii/S0944501313000463
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The genetic improvement of biomining bacteria including Acidithiobacillus caldus could facilitate the bioleaching process of sulfur-containing minerals. However, the available vectors for use in A. caldus are very scanty and limited to relatively large broad-host-range IncQ plasmids. In this study, a set of small, mobilizable plasmid vectors (pBBR1MCS-6, pMSD1 and pMSD2) were constructed based on plasmid pBBR1MCS-2, which does not belong to the IncQ, IncW, or IncP groups. The function of the tac promoter on 5.8-kb pMSD2 was determined by inserting a kanamycin-resistant reporter gene. The resulting recombinant pMSD2-Km was successfully transferred by conjugation into A. caldus MTH-04 with transfer frequency of 1.38±0.64×10(-5). The stability and plasmid copy number of pMSD2-Km in A. caldus MTH-04 were 75±2.7% and 5-6 copies per cell, respectively. By inserting an arsABC operon into pMSD2, an arsenic-resistant recombinant pMSD2-As was constructed and transferred into A. caldus MTH-04 by conjugation. The arsenic tolerance of A. caldus MTH-04 containing pMSD2-As was obviously increased up to 45mM of NaAsO2. These vectors could be applied in genetic improvement of A. caldus as well as other bioleaching bacteria. 

Acidithiobacillus caldus; Arsenic tolerance; Broad-host-range plasmid; Plasmid copy number; tac promoter