GST-tagged mouse estrogen receptor alpha-transactivation domain fusion protein is specifically degraded during its over-expression in E. coli and purification

Glutathione S-transferase M1, T1, and P1 polymorphisms and risk of glioma: a meta-analysis

The relationship between genetic polymorphisms of glutathione S-transferase (GST) and the development of glioma has been investigated in several epidemiologic studies. However these studies report inconsistent results. In order to quantitatively summarise the evidence for such a relationship, a meta-analysis is conducted. The PubMed database was searched from inception to January 2012 to identify relevant studies that met pre-stated inclusion criteria. We also reviewed reference lists from retrieved articles. Two researchers evaluated study eligibility and extracted the data independently, and disagreements were resolved by discussion. The principal outcome measure was the odds ratio (OR) with 95 % confidence interval (CI) for the risk of glioma associated with GSTM1, GSTT1, GSTP1 I105V or GSTP1 A114V. This meta-analysis included 11 case-control studies, which included 2,404 glioma cases and 6,379 controls. The combined results based on all studies showed that there was no association between any of the GST variants and the risk of glioma (for GSTM1: pooled OR = 1.03; 95 % CI, 0.92-1.15; for GSTT1: pooled OR = 1.12; 95 % CI, 0.90-1.40; for GSTP1 I105V: pooled OR = 0.92; 95 % CI, 0.64-1.31 and for GSTP1 A114V: pooled OR = 1.14; 95 % CI, 0.97-1.34). Subgroup analyses showed that GSTP1 A114V genotype was associated with an increased risk of other histopathologic glioma except glioblastoma multiforme (GBM) (pooled OR = 1.30; 95 % CI = 1.06-1.60); no relationship was found between other GST variants and histopathologic groups. In conclusion, our meta-analysis suggests no association between GST variants and the risk of glioma. However, the significant risk elevation is present between GSTP1 A114V genotype and other histopathologic glioma except GBM.

Soluble expression and purification of Brucella cell surface protein (BCSP31) of Brucella melitensis and preparation of anti-BCSP31 monoclonal antibodies

Brucella cell surface protein (BCSP31) is potentially useful for diagnosing brucellosis. We aimed to establish a monoclonal antibody (MAb) against Brucella melitensis BCSP31 and to investigate its distribution in diagnosis. Soluble recombinant BCSP31 was successfully expressed and purified. Two MAbs (1F1 and 1E5) against B. melitensis BCSP31, effective in detecting both recombinant and cellular proteins, were obtained and characterized. The MAbs did not react with Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Mycobacterium tuberculosis, or Bacillus aeruginosus, but strongly reacted with BCSP31 and B. melitensis by ELISA and Western blot analysis. We also tested different Brucella species and brucellosis using the prepared anti-BCSP31 MAbs. BCSP31 and anti-BCSP31 MAbs may play important roles in future research in diagnosing brucellosis.

Overexpression of mouse estrogen receptor-β decreases but its transactivation and ligand binding domains increase the growth characteristics of E. coli

Escherichia coli is one of the most common and widely used prokaryotic hosts for the expression of recombinant proteins. The overexpression of recombinant proteins occasionally increases bacterial growth but sometimes reduces it and becomes lethal to the host cells. Here, we report the overexpression of mouse ER-β and its domains in the prokaryotic expression system and its opposite effect on the growth characteristics of E. coli. ER-β protein was immunologically detected as a 53 kDa his-tag protein in the pellet of the bacterial lysate. Its overexpression, as reflected by the total protein content and expression pattern, resulted in the decrease of bacterial growth. However, the overexpression of ER-β transactivation domain (TAD) using pIVEX and ligand binding domain (LBD) using pRSETA in E. coli BL21 (DE3) show opposite pattern. TAD was immunologically detected as 20 kDa and LBD as 22 kDa protein in the supernatant of the bacterial lysate and their overexpression increased the bacterial growth.

Molecular analysis and recombinant expression of bovine neutrophil β-defensin 12 and its antimicrobial activity

To analyze molecular characteristics and antimicrobial activity of bovine neutrophil β-defensin 12 (BNBD12), Pro-BNBD12 gene was amplified from Chinese Holstein cow using reverse transcription polymerase chain reaction. Based on the sequence of mature BNBD12 and codon preference in E. coli, a modified mature BNBD12 cDNA was synthesized, cloned into pET32a (+) vector and expressed in E. coli BL21 as a 26 kD fusion protein after isopropyl β-D-1-thiogalactopyranoside induction. The expressed mature BNBD12 accounted for 21.4% of total protein. 0.05 mg/ml purified BNBD12 had antimicrobial activity against both E. coli and S. aureus in vitro assayed by agar diffusion method. Electron microscopy found that BNBD12 treatment of E. coli and S. aureus could induce cell content leakage. Taking together, BNBD12 protein was successfully expressed in E. coli and it has antimicrobial activity against both Gram-positive and negative bacteria and potentials in control of mastitis clinically.