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Molecular characterization of a novel big defensin from clam Venerupis philippinarum.

Zhao J, Li C, Chen A, Li L, Su X, Li T - PLoS ONE (2010)

Bottom Line: The mRNA transcript of VpBD was up-regulated significantly during the first 24 hr after Vibrio anguillarum challenge, which was 7.4-fold increase compared to that of the control group.Then the expression decreased gradually from 24 hr to 96 hr, and the lowest expression level was detected at 96 hr post-infection, which was still 3.9-fold higher than that of control.The rVpBD displayed broad-spectrum inhibitory activity towards all tested bacteria with the highest activity against Staphyloccocus aureus and Pseudomonas putida.

View Article: PubMed Central - PubMed

Affiliation: Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.

ABSTRACT
Antimicrobial peptides (AMPs) are important mediators of the primary defense mechanism against microbial invasion. In the present study, a big defensin was identified from Venerupis philippinarum haemocytes (denoted as VpBD) by RACE and EST approaches. The VpBD cDNA contained an open reading frame (ORF) of 285 bp encoding a polypeptide of 94 amino acids. The deduce amino acid sequence of VpBD shared the common features of big defensin including disulfide array organization and helix structure, indicating that VpBD should be a new member of the big defensin family. The mRNA transcript of VpBD was up-regulated significantly during the first 24 hr after Vibrio anguillarum challenge, which was 7.4-fold increase compared to that of the control group. Then the expression decreased gradually from 24 hr to 96 hr, and the lowest expression level was detected at 96 hr post-infection, which was still 3.9-fold higher than that of control. The mature peptide of VpBD was recombined in Escherichia coli and purified for minimum inhibitory concentration (MIC) determination. The rVpBD displayed broad-spectrum inhibitory activity towards all tested bacteria with the highest activity against Staphyloccocus aureus and Pseudomonas putida. These results indicated that VpBD was involved in the host immune response against bacterial infection and might contribute to the clearance of invading bacteria.

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SDS-PAGE analysis of recombinant VpBD.After electrophoresis, the gel was visualized by Coomassie brilliant blue R250 staining. Lane M: protein molecular standard; lane A: negative control for rVpBD (without induction); lane B: induced expression of rVpBD; lane C: purified rVpBD.
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pone-0013480-g004: SDS-PAGE analysis of recombinant VpBD.After electrophoresis, the gel was visualized by Coomassie brilliant blue R250 staining. Lane M: protein molecular standard; lane A: negative control for rVpBD (without induction); lane B: induced expression of rVpBD; lane C: purified rVpBD.

Mentions: The recombinant plasmid pET-21a-VpBD was transformed and expressed in E. coli BL21(DE3)-pLysS. After IPTG induction for 3 h, the whole cell lysate analyzed by SDS-PAGE revealed a distinct band with a molecular weight of 9.75 kDa (Fig. 4 lane B), which was further purified to homogeneity by HiTrap Chelating Columns (Fig. 4 lane C). Total of 0.9 mg purified protein was yield from 50 ml bacterial culture in the end.


Molecular characterization of a novel big defensin from clam Venerupis philippinarum.

Zhao J, Li C, Chen A, Li L, Su X, Li T - PLoS ONE (2010)

SDS-PAGE analysis of recombinant VpBD.After electrophoresis, the gel was visualized by Coomassie brilliant blue R250 staining. Lane M: protein molecular standard; lane A: negative control for rVpBD (without induction); lane B: induced expression of rVpBD; lane C: purified rVpBD.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2958110&req=5

pone-0013480-g004: SDS-PAGE analysis of recombinant VpBD.After electrophoresis, the gel was visualized by Coomassie brilliant blue R250 staining. Lane M: protein molecular standard; lane A: negative control for rVpBD (without induction); lane B: induced expression of rVpBD; lane C: purified rVpBD.
Mentions: The recombinant plasmid pET-21a-VpBD was transformed and expressed in E. coli BL21(DE3)-pLysS. After IPTG induction for 3 h, the whole cell lysate analyzed by SDS-PAGE revealed a distinct band with a molecular weight of 9.75 kDa (Fig. 4 lane B), which was further purified to homogeneity by HiTrap Chelating Columns (Fig. 4 lane C). Total of 0.9 mg purified protein was yield from 50 ml bacterial culture in the end.

Bottom Line: The mRNA transcript of VpBD was up-regulated significantly during the first 24 hr after Vibrio anguillarum challenge, which was 7.4-fold increase compared to that of the control group.Then the expression decreased gradually from 24 hr to 96 hr, and the lowest expression level was detected at 96 hr post-infection, which was still 3.9-fold higher than that of control.The rVpBD displayed broad-spectrum inhibitory activity towards all tested bacteria with the highest activity against Staphyloccocus aureus and Pseudomonas putida.

View Article: PubMed Central - PubMed

Affiliation: Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.

ABSTRACT
Antimicrobial peptides (AMPs) are important mediators of the primary defense mechanism against microbial invasion. In the present study, a big defensin was identified from Venerupis philippinarum haemocytes (denoted as VpBD) by RACE and EST approaches. The VpBD cDNA contained an open reading frame (ORF) of 285 bp encoding a polypeptide of 94 amino acids. The deduce amino acid sequence of VpBD shared the common features of big defensin including disulfide array organization and helix structure, indicating that VpBD should be a new member of the big defensin family. The mRNA transcript of VpBD was up-regulated significantly during the first 24 hr after Vibrio anguillarum challenge, which was 7.4-fold increase compared to that of the control group. Then the expression decreased gradually from 24 hr to 96 hr, and the lowest expression level was detected at 96 hr post-infection, which was still 3.9-fold higher than that of control. The mature peptide of VpBD was recombined in Escherichia coli and purified for minimum inhibitory concentration (MIC) determination. The rVpBD displayed broad-spectrum inhibitory activity towards all tested bacteria with the highest activity against Staphyloccocus aureus and Pseudomonas putida. These results indicated that VpBD was involved in the host immune response against bacterial infection and might contribute to the clearance of invading bacteria.

Show MeSH
Related in: MedlinePlus