• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.552-558
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• 2023

Levulinic acid (LA) is a valuable chemical used in fuel additives, fragrances, and polymers. In this study, we proposed possible biosynthetic pathways for LA production from lignin and poly(ethylene terephthalate). We also created a genetically encoded biosensor responsive to LA, which can be used for screening and evolving the LA biosynthesis pathway genes, by employing an LvaR transcriptional regulator of Pseudomonas putida KT2440 to express a fluorescent reporter gene. The LvaR regulator senses LA as a cognate ligand. The LA biosensor was first examined in an Escherichia coli strain and was found to be non-functional. When the host of the LA biosensor was switched from E. coli to P. putida KT2440, the LA biosensor showed a linear correlation between fluorescence intensity and LA concentration in the range of 0.156-10 mM LA. In addition, we determined that 0.156 mM LA was the limit of LA detection in P. putida KT2440 harboring an LA-responsive biosensor. The maximal fluorescence increase was 12.3-fold in the presence of 10 mM LA compared to that in the absence of LA. The individual cell responses to LA concentrations reflected the population-averaged responses, which enabled high-throughput screening of enzymes and metabolic pathways involved in LA biosynthesis and sustainable production of LA in engineered microbes.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.441-453
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• 2014

Antibiotics in the diets for poultry were not only used for avoiding and (or) control bacterial infections but for promoting growth of the birds. However, there has been massive concerns of negative effects of antibiotics on human health such as development of antibiotics-resistance bacteria and (or) genes. Subsequently, some of countries (i.e., European Union member of country and South Korea) banned the use of antibiotics as growth promoters in the diets for livestock industries in 2006 and 2011, respectively. Thus, it has become important to develop feeding strategies and feed additives to control and reduce the occurrence of diseases in livestock without using in-feed antibiotics. In this review, therefore, it is attempted to gather information with respect to (1) understanding the digestive physiology and (2) knowledge pertaining to interaction linking feed additives and its physiological and metabolic responses in broiler chickens.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.7
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• pp.912-918
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• 2011

Newly born lambs have to face challenges in a new environment totally different from that of the uterus. Adaptation to extra-uterine life involves functional changes with almost each organ and system in the body undergoing a series of metabolic and anatomical modifications. Failure to adapt the extra-uterine environment can not only lead to homeostatic disturbances but also lead to the death of the affected lambs. Hematological parameters of newly born lambs show variability that differs between breeds of lambs. The purpose of present study was to determine homeostatic responses and physiological reference values in Kajli breed lambs occurring in the neonatal period through changes in blood profile, respiratory rate, heart rate, live weight and rectal, scrotal and skin temperatures. For this purpose, sixteen clinically fit lambs (males = 10 and females = 6) with a mean body weight $6.92{\pm}0.46$ kg were selected. Physiological data of selected parameters of each Kajli lamb was recorded at three day intervals and hematological parameters at five days for a period of 30 days. In general, statistical analysis showed a significant effect of time (p<0.001) on all the studied physiological and hematological parameters except platelets counts, white blood cells and hemoglobin concentration. The results documented in the current study are an addition to existing knowledge of the physiology of Kajli sheep breed should be helpful in developing feeding, disease diagnoses and treatment protocols for newborn Kajli stock.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.275-281
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• 2013

Low temperature is one of the major environmental factors that affect productivity including reduced growth and budding of vines, and changes of metabolic processes in grape (Vitis spp.). To screen the specific expression of abiotic stress-related genes against cold treatment in 'Kyoho' and 'Campbell Early' grapevines, expression of various defense-related genes was investigated by RT-PCR and real-time PCR. Among the 67 genes analyzed by RT-PCR and real-time PCR, 17 and 16 types of cDNA were up-regulated, while 5 and 6 types were down-regulated in cold-treated 'Kyoho' and 'Campbell Early' grapevines, respectively. Genes encoding carotene (Cart3564 and Cart4472), chalcone isomerase (CHI), cytochrome P450 (CYP), flavonol synthase (FLS), endo-${\beta}$-glucanase precursor (Glu), glutathione peroxidase (GPX), glutathione-S-transferase (GST), leucine-rich repeats (LRR), manganese superoxide dismutase (Mn-SOD), phenylalanine ammonia lyase (PAL), polygalacturonase-inhibiting protein (PGIP), proline rich protein 2 (PRP2), small heat shock protein (sHSP), temperature induced lipocalin (TIL), and thaumatin-like protein (TLP) were up-regulated, while those encoding CBF like transcription factor (CBF1), chitinase-like protein (CLP), cold induced protein (CIP), glycerol-3-phosphate acyltransferase (GPAT), and mitogen-activated protein kinase (MAPK) were down-regulated by low temperature treatment in both in 'Kyoho' and 'Campbell Early'.

• International Journal of Vascular Biomedical Engineering
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• v.2 no.2
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• pp.1-9
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• 2004

The history of studies in biology regarding reactive oxygen species (ROS) is approximately 40 years. During the initial 30 years, it appeared that these studies were mainly focused on the toxicity of ROS. However, recent studies have identified another action regarding oxidative signaling, other than toxicity of ROS. Basically, it is suggested that ROS are reactive, and degenerate to biomolecules such as DNA and proteins, leading to deterioration of cellular functions as an oxidative stress. On the other hand, recent studies have shown that ROS act as oxidative signaling in cells, resulting in various gene expressions. Recently ROS emerged as critical signaling molecules in cardiovascular research. Several studies over the past decade have shown that physiological effects of vasoactive factors are mediated by these reactive species and, conversely, that altered redox mechanisms are implicated in the occurrence of metabolic and cardiovascular diseases ROS is a collective term often used by scientist to include not only the oxygen radicals($O2^{-{\cdot}},\;{^{\cdot}}OH$), but also some non-radical derivatives of oxygen. These include hydrogen peroxide, hypochlorous acid (HOCl) and ozone (O3). The superoxide anion ($O2^{-{\cdot}}$) is formed by the univalent reduction of triplet-state molecular oxygen ($^3O_2$). Superoxide dismutase (SOD)s convert superoxide enzymically into hydrogen peroxide. In biological tissues superoxide can also be converted nonenzymically into the nonradical species hydrogen peroxide and singlet oxygen ($^1O_2$). In the presence of reduced transition metals (e.g., ferrous or cuprous ions), hydrogen peroxide can be converted into the highly reactive hydroxyl radical (${^{\cdot}}OH$). Alternatively, hydrogen peroxide may be converted into water by the enzymes catalase or glutathione peroxidase. In the glutathione peroxidase reaction glutathione is oxidized to glutathione disulfide, which can be converted back to glutathione by glutathione reductase in an NADPH-consuming process.

• BMB Reports
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• v.47 no.9
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• pp.494-499
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• 2014

NADH:quinone oxidoreductase 1 (NQO1) is known to be involved in the regulation of energy synthesis and metabolism, and the functional studies of NQO1 have largely focused on metabolic disorders. Here, we show for the first time that compared to NQO1-WT mice, NQO1-KO mice exhibited a marked increase of permeability and spontaneous inflammation in the gut. In the DSS-induced colitis model, NQO1-KO mice showed more severe inflammatory responses than NQO1-WT mice. Interestingly, the transcript levels of claudin and occludin, the major tight junction molecules of gut epithelial cells, were significantly decreased in NQO1-KO mice. The colons of NQO1-KO mice also showed high levels of reactive oxygen species (ROS) and histone deacetylase (HDAC) activity, which are known to affect transcriptional regulation. Taken together, these novel findings indicate that NQO1 contributes to the barrier function of gut epithelial cells by regulating the transcription of tight junction molecules.

• Korean Journal of Environmental Agriculture
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• v.25 no.4
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• pp.371-381
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• 2006

New proteomic techniques have been pioneered extensively in recent years, enabling the high-throughput and systematic analyses of cellular proteins in combination with bioinformatic tools. Furthermore, the development of such novel proteomic techniques facilitates the elucidation of the functions of proteins under stress or disease conditions, resulting in the discovery of biomarkers for responses to environmental stimuli. The ultimate objective of proteomics is targeted toward the entire proteome of life, subcellular localization biochemical activities, and the regulation thereof. Comprehensive analysis strategies of proteomics can be classified into three categories: (i) protein separation via 2-dimensional gel electrophoresis (2-DE) or liquid chromatography (LC), (ii) protein identification via either Edman sequencing or mass spectrometry (MS), and (iii) proteome quantitation. Currently, MS-based proteomics techniques have shifted from qualitative proteome analysis via 2-DE or 2D-LC coupled with off-line matrix assisted laser desorption ionization (MALDI) and on-line electrospray ionization (ESI) MS, respectively, toward quantitative proteome analysis. In vitro quantitative proteomic techniques include differential gel electrophoresis with fluorescence dyes. protein-labeling tagging with isotope-coded affinity tags, and peptide-labeling tagging with isobaric tags for relative and absolute quantitation. In addition, stable isotope-labeled amino acids can be in vivo labeled into live culture cells via metabolic incorporation. MS-based proteomics techniques extend to the detection of the phosphopeptide mapping of biologically crucial proteins, which ale associated with post-translational modification. These complementary proteomic techniques contribute to our current understanding of the manner in which life responds to differing environment.

• Clinical and Experimental Pediatrics
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• v.58 no.12
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• pp.484-490
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• 2015

Purpose: To determine the efficacy and safety of oral propranolol as a first-line treatment for superficially located infantile hemangioma (IH) and propose an assessment tool to measure treatment response. Methods: Patients with superficial IH under 1 year of age were prospectively recruited between May 2012 and December 2013 at the Department of Pediatrics of Chungbuk National University Hospital. Propranolol was administered to 12 infants (median age, 3.8 months) while monitoring cardiovascular and adverse metabolic effects. If a patient showed no adverse events, the dosage was gradually increased up to 3 mg/kg/day and maintained for 1 year. We used our own scoring system to assess treatment response using parameters like change in color, and longest diameter, and thickness of the IH. Results: Eleven out of 12 patients completed the protocol with consistent improvement of hemangiomas during therapy. Patients on propranolol showed a more than 50% involution in the first 3 months, with additional steady involution until 1 year. Patients with the highest scores at 1 month maintained their score and showed better responses until treatment termination. The patient with the lowest score at 1 month did not show any further regression and stopped propranolol treatment 4 months after initiation. In two children with recurrences after successful therapeutic regression, propranolol was effective after being reintroduced. Propranolol treatment was not interrupted in any patient due to adverse events. Conclusion: Oral propranolol at 3 mg/kg/day showed a consistent, rapid, and therapeutic effect on superficial IHs without significant adverse events.

• Nutrition Research and Practice
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• v.3 no.2
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• pp.128-133
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• 2009

Few studies have examined short tenn responses to the different contents of carbohydrate or fat in the meal, although long tenn effects of the high fat meal have been considered as compound risk factor for metabolic disorders. The aim of this study was to investigate the postprandial changes of plasma glucose, insulin and lipids upon intakes of high carbohydrate or high fat meal in young healthy women. Subjects were randomly assigned to either the high carbohydrate meal (HCM, 75% carbohydrate, n=13) or the high fat meal (HFM, 60% fat, n=12) groups. The meals were prepared as isocaloric typical Korean menu. Blood samples were obtained prior to and 30, 60, 90, 120, 180 and 240 minute after the meal. There were no significant differences on fasting blood parameters including glucose, insulin, lipids concentrations between the groups prior to the test. The HCM had higher blood glucose and insulin concentrations, reached the peak at 30 min and maintained for 240 min compared to the HFM (P<0.05). The HFM had higher plasma triglyceride (TG) and free fatty acid (FFA) concentrations, reached the peak at 120 min and maintained for 240 min compared to the HCM (P<0.05). It is concluded that macronutrients content in the meal may be an important determinant of postprandial substrate utilization in healthy women.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.3
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• pp.381-387
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• 1999

Two experiments were conducted to subdivide threonine (exp. 1) and glycine (exp. 2) requirements of broilers into maintenance and growth requirements. Purified diets containing five graded levels of threonine (exp. 1) and glycine (exp. 2) were fed to growing chicks to estimate threonine (exp. 1) and glycine (exp. 2) requirements for growth and maintenance. A model developed to divide threonine requirement for maintenance from that for growth yielded a requirement for growth of 8.946 mg/g weight gain and 0.341 mg/mg N gain; the maintenance requirement was 0.033 or 0.030 mg per unit of metabolic body size $(Wg^{0.75})$. The plateau of plasma threonine concentration occurred at 279.4 mg threonine intake/day. The total threonine requirement was 289.1 mg/day or 0.69% of the diet, 294.1 mg/day or 0.71% of the diet based on weight gain and nitrogen gain responses, respectively. These estimates were in close agreement with previous estimates of threonine requirements. From the relationship of weight gain to N gain, 5.46% of the retained protein consisted of threonine; the reported threonine content of chick muscle was 4.02%. The glycine requirement for maintenance could not be determined due to failure to obtain data allowing extrapolation to zero response. However, ADG increased slightly up to 0.56% glycine.