Analysis Of Differentially Expressed Genes From Sulfobacillus Sp.TPY In Response To Copper Ions And Mercy Ions

Microorganism is the most abundant biological resource on the earth, and acidophilic bioleaching microorganism is one of the important members. These microorganism have developed an unique metabolism pathways and recovery mechanism to adapt to extreme environment(low pH and high concentration of heavy metal ions), which is impossible for most microorganism. Thus the heavy metals resistant mechanism of bioleaching microorganism becoming an important biology resource. The new genes, proteins and the biological active materials may play an important role in gene engineering, protein engineering, environmental engineering and exploiting of mineral resources.A moderate thermophilic acidophic bacterium was isolated from hydrothermal vent of the Pacific Ocean. Based on the morphological characteristics, physiological and biochemical characteristics and the phylogenetic analysis of 16S rDNA sequence, the strain is identified as Sulfobacillus, named Sulfobacillus sp. TPY. The strain TPY is Gram positive, rod-shaped in (0.3-0.5×2.0-2.5um). The optimal growth temperature is about 50℃, the optimal pH is 1.8. The TPY strain not only can utilize iron and element sulfur as electron donor, but also utilize yeast extracts, glucose, peptone and glycerol. When using ferrous ions or element sulfur as energy source, mixed with a little yeast extracts, TPY grown better.TPY can adapt to high concentration of Cu²⁺ or Hg²⁺, which can grow in 50mM Cu²⁺ or 10^-6mM Hg²⁺. Thus random arbitrarily primed PCR (RAP-PCR) was used to isolate and identify differentially expressed genes of bacteria grown in 50mM Cu²⁺ compared to those of 0 mM Cu²⁺, and grown in 10^-6mM Hg²⁺ compared to those of 0 mM Hg²⁺, respectively. The RAP-PCR was optimized and the percentage of positive cDNA fragment was remarkably increased. 57 differential cDNA fragments in total were isolated, and 32 different cDNAs were analyzed by Northern blot, among which 18 were confirmed to be differentially expressed at the transcriptional levels under different concentration of Cu²⁺. And 48 differential cDNA fragments in total were isolated, and 23 different cDNAs were analyzed by Northern blot, among which 14 were confirmed to be differentially expressed at the transcriptional levels under different concentration of Hg²⁺.These genes reflected a profile of organismal adaptation, and were involved in many physiological processes such as cell membrane alterations, ions transportion, antioxidation recovery, regulatory adaptive response and metabolism. This study provides a better understanding of the adaptation of bioleaching bacteria to high concentration of heavy metal ions.