High-yielding plasmid extraction method from acidophilic heterotrophic bacteria of the genus Acidiphilium

Effects of SCR-3 on the immunosuppression accompanied with the systemic inflammatory response syndrome

Steroid receptor coactivator-3 (SRC-3) is a multifunctional protein that plays an important role in mammary gland growth, development, and tumorigenesis. In this study, SCR-3 gene knockout mice were used to study the effects of SCR-3 on the immunosuppression accompanied with systemic inflammatory response syndrome (SIRS). Bacterial clearance assay was performed by blood culture and frozen sections, and the results showed that the absence of SCR-3 protein serious damaged the innate immune system and the body's ability to inactivate or phagocytosis of bacteria was significantly decreased, and the absence of SCR-3 protein also weakened phagocytes' ability to degrade bacteria and their metabolites. Furthermore, animal model of inflammatory reaction was established and the immune function was determined, and the results revealed that SRC-3 protein may play an important role in maintenance of T-cells' immune function, and severe T-cell immune function disorder would be resulted once SRC-3 protein is missing. In addition, the results of our study showed the steady-state of lymphocyte subsets was destroyed after SIRS, leading the suppression of cellular immune function, and the absence of SCR-3 protein may aggravate the suppression of T-lymphocyte function. Therefore, the present study demonstrated that the absence of SCR-3 protein would aggravate immunosuppression. In addition, SRC-3 protein is a significant regulator of infection and inflammation, and SRC-3 protein play an essential role in the development of immunosuppression accompanied with SIRS.

Plasmid encoded AcrAB-TolC tripartite multidrug-efflux system in Acidiphilium symbioticum H8

Acidophilic bacterium, Acidiphilium symbioticum H8, is resistant to high levels of several heavy metals, hydrophobic agents, and organic solvents. The approximately 9.6 kb plasmid pASH8, was purified, digested with HindIII, and sub-cloned in pUC19 at the respective site. Three different fragment size clones were achieved. The clones were completely sequenced and analyzed. The first clone encodes for a single putative open reading frame (ORF), which showed significant homology to several rusticyaninA1 proteins. The second clone encodes for a 43-kDa protein, which has conserved domain homology with several outer envelop TolC proteins. The clone with pASH8 tolC gene can functionally complement an Escherichia coli tolC mutant strain, making it resistant to several toxic hydrophobic agents, earlier for which it was sensitive. The tolC gene was found to be essential for imparting resistance to the clone toward these toxic hydrophobic agents. The third clone encodes for a putative 318-aa AcrA (acriflavine resistance protein A) protein and the clone was resistance to plasmid curing dye acriflavine. The clone also has a truncated ORF, which showed significant homology to cation-efflux pump AcrB. This study is the first to report a multi-drug efflux system to be encoded on a plasmid of any Acidiphilium strain.

Nucleotide sequence analysis of cryptic plasmid pAM5 from Acidiphilium multivorum

Plasmid pAM5 of Acidiphilium multivorum JCM-8867 has been completely sequenced by initial cloning of HindIII-PstI fragments followed by primer walking. It has a size of 5161bp and single site for several restriction enzymes as revealed by DNA sequencing. Sequence analysis predicts five putative open reading frames. ORF1 and ORF3 show significant identity with various plasmid encoded mobilization (Mob) and replication initiation (Rep) proteins, respectively. The putative Mob protein has several characteristics of the MOB(Q) family having the motifs with conserved amino acid residues. Upstream of the Mob ORF, there exists a 34bp oriT region having a nic consensus sequence. The constructed plasmid pSK1 bearing pAM5 mob region can be mobilized to Escherichia coli in presence of conjugative plasmid pRK2013. The replication module comprises of several DnaA like boxes, several perfect direct and inverted repeats, a potential prokaryotic promoter and putative rep gene. The rep module is very similar to several theta replicating iteron family plasmids, suggesting pAM5 replication to follow the same course. Any phenotypic character determinant (e.g., metal resistance, antibiotic resistance etc.) gene is absent in pAM5, suggesting this plasmid to be cryptic in nature. However, a pAM5 derivative plasmid named pSK2, containing the putative pAM5 rep region, can replicate and be stably maintained in Acidiphilium, Acidocella, and E. coli strains; it can also carry foreign DNA fragments. Thus, pSK2 could serve as a cloning shuttle vector between these bacteria. It was observed that pAM5 Rep is essential for pSK2 to replicate in acidophiles. In its natural host, A. multivorum JCM-8867, pAM5 maintains a copy number of 50-60, and its derivative pSK2 maintains a comparatively, higher copy number in E. coli than in acidophiles.