T. Temsiripong - Academia.edu (original) (raw)
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Papers by T. Temsiripong
Journal of Applied Microbiology, 2017
Aims: A novel antibacterial peptide from Crocodylus siamensis hemoglobin hydrolysate (CHHs) was c... more Aims: A novel antibacterial peptide from Crocodylus siamensis hemoglobin hydrolysate (CHHs) was characterised for antimicrobial activity. Methods and Results: CHHs was hydrolysed for 2 h (2h-CHH), 4 h (4h-CHH), 6 h (6h-CHH) and 8 h (8h-CHH). 8h-CHH showed antibacterial activity against Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia and Pseudomonas aeruginosa at concentrations of 20, 20, 20 and 10 mg ml-1 (w/v), respectively. Fluorescent microscopy revealed that 8h-CHH had bactericidal activity against E. coli and P. aeruginosa. β-galactosidase assay supported by RT-qPCR demonstrated that 8h-CHH resulted in differential expression of genes involved in iron homeostasis (ftnA and bfd) and oxidative stress (sodA, soxR and oxyR). Siderophore assay indicated that 8h-CHH also impaired siderophore production with diminished expression of pvdF. This pattern of gene expression suggests that 8h-CHH triggers the release of free ferric ions in the cytoplasm. However, decreased expression of genes associated with the SOS response (recA and lexA) in combination with neutral comet revealed that no DNA damage was caused by 8h-CHH. Membrane permeabilisation assay indicated that 8h-CHH caused membrane leakage thought to mediate the antibacterial and iron-stress responses observed, due to loss of regulated iron transport. The novel active peptide from 8h-CHH was determined as QAIIHNEKVQAHGKKVL (QL17), with 41% hydrophobicity and +2 net charge. Conclusions: The QAIIHNEKVQAHGKKVL fragment of Crocodylus siamensis hemoglobin is antibacterial via a mechanism that likely relies on iron dysregulation and oxidative stress which results in bacterial death. Significance and Impact of the Study: We have described for the first time, a novel peptide derived from Crocodylus siamensis hemoglobin hydrolysate, that has the potential to be developed as a novel antimicrobial peptide.
Food Research International, 2007
The inXuence of sucrose on thermal and rheological properties of tapioca starch (TS)-tamarind see... more The inXuence of sucrose on thermal and rheological properties of tapioca starch (TS)-tamarind seed xyloglucan (XG) mixtures was investigated. Rapid visco-analysis proWles of 5% w/w TS/XG dispersions at diVerent mixing ratios revealed that peak and Wnal viscosities increased with increasing sucrose and XG contents. Loss tangent of each mixing ratio of TS/XG pastes determined from dynamic rheometry exhibited a lower value with increasing sucrose, suggesting solid-like properties contributed from the dissolved sucrose in the systems. Gelatinization temperatures of 25% w/w TS/XG at mixing ratios of 10/0 and 9/1 increased with increasing sucrose content whereas the gelatinization enthalpy of pastes increased in the presence of high sucrose concentration. Sucrose increased the stiVness and hardness of the 25% w/w TS/XG gels (mixing ratios of 10/0, 9.5/0.5 and 9/1) from the compression test. These results suggest that sucrose delays the gelatinization of TS and XG mixtures and strengthens the gels by increasing the elastic component.
Journal of Applied Microbiology, 2017
Aims: A novel antibacterial peptide from Crocodylus siamensis hemoglobin hydrolysate (CHHs) was c... more Aims: A novel antibacterial peptide from Crocodylus siamensis hemoglobin hydrolysate (CHHs) was characterised for antimicrobial activity. Methods and Results: CHHs was hydrolysed for 2 h (2h-CHH), 4 h (4h-CHH), 6 h (6h-CHH) and 8 h (8h-CHH). 8h-CHH showed antibacterial activity against Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia and Pseudomonas aeruginosa at concentrations of 20, 20, 20 and 10 mg ml-1 (w/v), respectively. Fluorescent microscopy revealed that 8h-CHH had bactericidal activity against E. coli and P. aeruginosa. β-galactosidase assay supported by RT-qPCR demonstrated that 8h-CHH resulted in differential expression of genes involved in iron homeostasis (ftnA and bfd) and oxidative stress (sodA, soxR and oxyR). Siderophore assay indicated that 8h-CHH also impaired siderophore production with diminished expression of pvdF. This pattern of gene expression suggests that 8h-CHH triggers the release of free ferric ions in the cytoplasm. However, decreased expression of genes associated with the SOS response (recA and lexA) in combination with neutral comet revealed that no DNA damage was caused by 8h-CHH. Membrane permeabilisation assay indicated that 8h-CHH caused membrane leakage thought to mediate the antibacterial and iron-stress responses observed, due to loss of regulated iron transport. The novel active peptide from 8h-CHH was determined as QAIIHNEKVQAHGKKVL (QL17), with 41% hydrophobicity and +2 net charge. Conclusions: The QAIIHNEKVQAHGKKVL fragment of Crocodylus siamensis hemoglobin is antibacterial via a mechanism that likely relies on iron dysregulation and oxidative stress which results in bacterial death. Significance and Impact of the Study: We have described for the first time, a novel peptide derived from Crocodylus siamensis hemoglobin hydrolysate, that has the potential to be developed as a novel antimicrobial peptide.
Food Research International, 2007
The inXuence of sucrose on thermal and rheological properties of tapioca starch (TS)-tamarind see... more The inXuence of sucrose on thermal and rheological properties of tapioca starch (TS)-tamarind seed xyloglucan (XG) mixtures was investigated. Rapid visco-analysis proWles of 5% w/w TS/XG dispersions at diVerent mixing ratios revealed that peak and Wnal viscosities increased with increasing sucrose and XG contents. Loss tangent of each mixing ratio of TS/XG pastes determined from dynamic rheometry exhibited a lower value with increasing sucrose, suggesting solid-like properties contributed from the dissolved sucrose in the systems. Gelatinization temperatures of 25% w/w TS/XG at mixing ratios of 10/0 and 9/1 increased with increasing sucrose content whereas the gelatinization enthalpy of pastes increased in the presence of high sucrose concentration. Sucrose increased the stiVness and hardness of the 25% w/w TS/XG gels (mixing ratios of 10/0, 9.5/0.5 and 9/1) from the compression test. These results suggest that sucrose delays the gelatinization of TS and XG mixtures and strengthens the gels by increasing the elastic component.