Bong Hyun Sung

Lignin, an aromatic polymer found in plants, has been studied for years in many biological fields. Initially, when biofuel was produced from lignocellulosic biomass, lignin was regarded as waste generated by the biorefinery and had to be removed, because of its inhibitory effects on fermentative bacteria. Although it has since proven to be a natural resource for bio-products with considerable potential, its utilization is confined by its complex structure. Hence, the microbial degradation of lig

Impaired endothelium-dependent vascular relaxation has been reported in patients with high cholesterol (HC), but the systemic effects of elevated cholesterol on blood pressure (BP) and BP reactivity to stress have not been studied. We examined the BP response to a standard mental arithmetic test (MAT) in 37 healthy, normotensive HC subjects and 33 normal cholesterol controls (NC). Both groups had similar age, body mass index, and gender distribution. HC had slightly higher systolic BP at baselin

Bacteria form biofilms by adhering to biotic or abiotic surfaces. This phenomenon causes several problems, including a reduction in the transport of mass and heat, an increase in resistance to antibiotics, and a shortening of the lifetimes of modules in bioindustrial fermentors. To overcome these difficulties, we created a biofilm production-deficient Escherichia coli strain, BD123, by deleting genes involved in curli biosynthesis and assembly, Delta(csgG-csgC); colanic acid biosynthesis and ass

Microbial diversity and complexity pose challenges in understanding the voluminous genetic information produced from whole-genome sequences, bioinformatics and high-throughput '-omics' research. These challenges can be overcome by a core blueprint of a genome drawn with a minimal gene set, which is essential for life. Systems biology and large-scale gene inactivation studies have estimated the number of essential genes to be ∼300-500 in many microbial genomes. On the basis of the essential gene

Food waste oil (FWO) is the most suitable raw material for economic biodiesel (BD) production, owing to its low price, sufficient supply, and waste disposal diversion. However, water in FWO inhibits BD production by Candida antarctica lipase B (CALB) which must be overcome. Here, a mutant lipase CALB1422 that catalyzes the ester synthesis in the presence of water was developed. The CALB1422 showed 91.1 % and 72.6 % BD conversion rates for soybean oil containing 2 % and 8 % water, respectively; w

Bacterial colonization and transmission via surfaces increase the risk of infection. In this study, we design and employ novel adhesive antimicrobial peptides to prevent bacterial contamination of surfaces. Repeats of 3,4-dihydroxy-L-phenylalanine (DOPA) were added to the C-terminus of NKC, a potent synthetic antimicrobial peptide, and the adhesiveness and antibacterial properties of the resulting peptides are evaluated. The peptide is successfully immobilized on polystyrene, titanium, and polyd

Pseudomonas putida is a promising strain for lignin valorisation. However, there is a dearth of stable and efficient systems for secreting enzymes to enhance the process. Therefore, a novel secretion system for recombinant lignin-depolymerising peroxidase was developed. By adopting a flagellar type III secretion system, P. putida KT-M2, a secretory host strain, was constructed and an optimal secretion signal fusion partner was identified. Application of the dye-decolourising peroxidase of P. put

The role of epinephrine in eliciting myocardial ischemia was examined in patients with coronary artery disease. Objective signs of ischemia and factors increasing myocardial oxygen consumption were compared during epinephrine infusion and supine bicycle exercise. Both epinephrine and exercise produced myocardial ischemia as evidenced by ST segment depression and angina. However, the mechanisms of myocardial ischemia induced by epinephrine were significantly different from those of exercise. Exer

We examined effectiveness classical music, sounds of nature and yoga in the reversal of potentially unfavorable hemodynamic changes associated with mental stress. Study group consisted of 12 healthy normotensive volunteers, ages ranging between 22–55 years. Mean BP of the group was 119/76 mmHg and HR was 70 bpm. Each subject was rested for 10–15 minutes and subjected to mental stress for 5 minutes in the form of serial subtraction from 3 digit numbers with different combination. It was followed

The bioconversion of 4-hydroxy-2-keto acid derivatives via aldol condensation of formaldehyde and pyruvate has received substantial attention as potential source of chemicals for production of amino acids, hydroxy carboxylic acids, and chiral aldehydes. We developed an environmentally friendly biocatalyst consisting of a novel thermostable class II pyruvate aldolase from Deinococcus radiodurans with maltose-binding protein (MBP-DrADL), which has specific activity of 46.3 µmol min^-1 mg

An improved and rapid genomic engineering method has been developed for the construction of -custom-designed microorganisms by scarless chromosomal gene knockouts. This method, which can be performed in 2 days, permits restructuring of the Escherichia coli genome via scarless deletion of selected genomic regions. The deletion process is mediated by a special plasmid, pREDI, which carries two independent inducible promoters: (1) an arabinose-inducible promoter that drives expression of λ-RED reco

Microbial infections remain a global health concern, calling for the urgent need to implement effective prevention measures. Antimicrobial peptides (AMPs) have been extensively studied as potential antimicrobial coating agents. However, an efficient and economical method for AMP production is lacking. Here, we synthesized the direct coating adhesive AMP, NKC-DOPA₅, composed of NKC, a potent AMP, and repeats of the adhesive amino acid 3,4-dihydroxyphenylalanine (DOPA) via an intein-med

To assess plasma norepinephrine (NE) and epinephrine (E) concentrations at onset of exercise induced myocardial ischemia the authors studied 10 male patients (PTS), age = 56 +/- 8, with angiographically proven coronary disease during multistage supine bicycle exercise (BEX). All drugs were stopped 7 days before study. Data were obtained at rest and each BEX stage. End points were angina or fatigue. Plasma NE and E were measured by radioenzymatic assay and hemodynamic responses and left ventricul