Production of highly pure R,R-2,3-butanediol for biological plant growth promoting agent using carbon feeding control of Paenibacillus polymyxa MDBDO.

BACKGROUND: Chemical fertilizers have greatly contributed to the development of agriculture, but alternative fertilizers are needed for the sustainable development of agriculture. 2,3-butanediol (2,3-BDO) is a promising biological plant growth promoter. RESULTS: In this study, we attempted to develop an effective strategy for the biological production of highly pure R,R-2,3-butanediol (R,R-2,3-BDO) by Paenibacillus polymyxa fermentation. First, gamma-ray mutagenesis was performed to obtain P. polymyxa MDBDO, a strain that grew faster than the parent strain and had high production of R,R-2,3-BDO. The activities of R,R-2,3-butanediol dehydrogenase and diacetyl reductase of the mutant strain were increased by 33% and decreased by 60%, respectively. In addition, it was confirmed that the carbon source depletion of the fermentation broth affects the purity of R,R-2,3-BDO through batch fermentation. Fed-batch fermentation using controlled carbon feeding led to production of 77.3 g/L of R,R-2,3-BDO with high optical purity (> 99% of C4 products) at 48 h. Additionally, fed-batch culture using corn steep liquor as an alternative nitrogen source led to production of 70.3 g/L of R,R-2,3-BDO at 60 h. The fed-batch fermentation broth of P. polymyxa MDBDO, which contained highly pure R,R-2,3-BDO, significantly stimulated the growth of soybean and strawberry seedlings. CONCLUSIONS: This study suggests that P. polymyxa MDBDO has potential for use in biological plant growth promoting agent applications. In addition, our fermentation strategy demonstrated that high-purity R,R-2,3-BDO can be produced at high concentrations using P. polymyxa.

Production of 1,2-propanediol from glycerol in Klebsiella pneumoniae GEM167 with flux enhancement of the oxidative pathway.

BACKGROUND: To support the sustainability of biodiesel production, by-products, such as crude glycerol, should be converted into high-value chemical products. 1,2-propanediol (1,2-PDO) has been widely used as a building block in the chemical and pharmaceutical industries. Recently, the microbial bioconversion of lactic acid into 1,2-PDO is attracting attention to overcome limitations of previous biosynthetic pathways for production of 1,2-PDO. In this study, we examined the effect of genetic engineering, metabolic engineering, and control of bioprocess factors on the production of 1,2-PDO from lactic acid by K. pneumoniae GEM167 with flux enhancement of the oxidative pathway, using glycerol as carbon source. RESULTS: We developed K. pneumoniae GEM167ΔadhE/pBR-1,2PDO, a novel bacterial strain that has blockage of ethanol biosynthesis and biosynthesized 1,2-PDO from lactic acid when glycerol is carbon source. Increasing the agitation speed from 200 to 400 rpm not only increased 1,2-PDO production by 2.24-fold to 731.0 ± 24.7 mg/L at 48 h but also increased the amount of a by-product, 2,3-butanediol. We attempted to inhibit 2,3-butanediol biosynthesis using the approaches of pH control and metabolic engineering. Control of pH at 7.0 successfully increased 1,2-PDO production (1016.5 ± 37.3 mg/L at 48 h), but the metabolic engineering approach was not successful. The plasmid in this strain maintained 100% stability for 72 h. CONCLUSIONS: This study is the first to report the biosynthesis of 1,2-PDO from lactic acid in K. pneumoniae when glycerol was carbon source. The 1,2-PDO production was enhanced by blocking the synthesis of 2,3-butanediol through pH control. Our results indicate that K. pneumoniae GEM167 has potential for the production of additional valuable chemical products from metabolites produced through oxidative pathways.

Enzymatic Synthesis of Glucosyl Rebaudioside A and its Characterization as a Sweetener.

Rebaudioside A was modified via glucosylation by recombinant dextransucrase of Leuconostoc lactis EG001 in Escherichia coli BL21 (DE3), forming single O-α-D-glucosyl-(1″→6') rebaudioside A with yield of 86%. O-α-D-glucosyl-(1″→6') rebaudioside A was purified using HPLC and Diaion HP-20 and its properties were characterized for possible use as a food ingredient. Almost 98% of O-α-D-glucosyl-(1″→6') rebaudioside A was dissolved after 15 days of storage at room temperature, compared to only 11% for rebaudioside A. Compared to rebaudioside A, O-α-D-glucosyl-(1″→6') rebaudioside A showed similar or improved acidic or thermal stability in commercial drinks. Thus, O-α-D-glucosyl-(1″→6') rebaudioside A could be used as a highly pure and improved sweetener with high stability in commercial drinks. PRACTICAL APPLICATION: The proposed method can be used to generate glucosyl rebaudioside A by enzymatic glucosylation. Simple glucosyl rebaudioside A exhibited high acid/thermal stability and improved sweetener in commercialized drinks. This method can be applied to obtain high value-added bioactive compounds by enzymatic modification.

Gamma-Aminobutyric Acid Production from a Novel Enterococcus avium JS-N6B4 Strain Isolated from Edible Insects.

Gamma-aminobutyric acid (GABA)-producing strains were isolated from four edible insects and subjected to 16S rRNA sequence analysis. Among the four GABA-producing bacteria, Enterococcus avium JS-N6B4 exhibited the highest GABA-production, while cultivation temperature, initial pH, aerobic condition, and mono-sodium glutamate (MSG) feeding were found to be the key factors affecting GABA production rate. The culture condition was optimized in terms of glucose, yeast extract, and MSG concentrations using response surface methodology (RSM). GABA production up to 16.64 g/l was obtained under the conditions of 7 g/l glucose, 45 g/l yeast extract, and 62 g/l MSG through the optimization of medium composition by RSM. Experimental GABA production was 13.68 g/l, which was close to the predicted value (16.64 g/l) calculated from the analysis of variance, and 2.79-fold higher than the production achieved with basic medium. Therefore, GABA-producing strains may help improve the GABA production in edible insects, and provide a new approach to the use of edible insects as effective food biomaterials.

Predictors of Discordance in the Assessment of Skeletal Muscle Mass between Computed Tomography and Bioimpedance Analysis.

Computed tomography (CT) and bioimpedance analysis (BIA) can assess skeletal muscle mass (SMM). Our objective was to identify the predictors of discordance between CT and BIA in assessing SMM. Participants who received a comprehensive medical health check-up between 2010 and 2018 were recruited. The CT and BIA-based diagnostic criteria for low SMM are as follows: Defined CT cutoff values (lumbar skeletal muscle index (LSMI) <1 standard deviation (SD) and means of 46.12 cm²/m² for men and 34.18 cm²/m² for women) and defined BIA cutoff values (appendicular skeletal muscle/height² <7.0 kg/m² for men and <5.7 kg/m² for women). A total of 1163 subjects were selected. The crude and body mass index (BMI)-adjusted SMM assessed by CT were significantly associated with those assessed by BIA (correlation coefficient = 0.78 and 0.68, respectively; p < 0.001). The prevalence of low SMM was 15.1% by CT and 16.4% by BIA. Low SMM diagnosed by CT was significantly associated with advanced age, female gender, and lower serum albumin level, whereas low SMM diagnosed by BIA was significantly associated with advanced age, female gender, and lower BMI (all p < 0.05). Upon multivariate analysis, age >65 years, female and BMI <25 kg/m² had significantly higher risks of discordance than their counterparts (all p < 0.05). We found a significant association between SMM assessed by CT and BIA. SMM assessment using CT and BIA should be interpreted cautiously in older adults (>65 years of age), female and BMI <25 kg/m².

Biochemical Characterization of Alkaliphilic Cyclodextran Glucanotransferase from an Alkaliphilic Bacterium, Paenibacillus daejeonensis.

Cycloisomaltooligosaccharide glucanotransferase (CITase) was isolated from alkaliphilic Paenibacillus daejeonensis via an amino acid homology search for the reported CITase. The recombinant alkaliphilic CITase (PDCITase) from P. daejeonensis was expressed in an Escherichia coli expression system and purified as a single protein band of 111 kDa. PDCITase showed optimum activity at pH 8.0 and retained 100% of activity within a broad pH range (7.0-11.5) after 18 h, indicating alkaliphilic or alkalistable CITase properties. In addition, PDCITase produced CI-7 to CI-17, CI-18, and CI-19, which are relatively large cycloisomaltooligosaccharides yet to be reported. Therefore, these large cycloisomaltooligosaccharides can be applied to the improvement of water solubility of pharmaceutical biomaterials.

Development and validation of an LC-MS/MS method for the determination of pelubiprofen and its active metabolite, trans-alcohol, in human plasma and its application to pharmacokinetic study.

A suitable liquid chromatography tandem mass spectrometry (LC-MS/MS) method is required to determine pelubiprofen and its active metabolite, trans-alcohol (M-D), in human plasma for pharmacokinetic studies of pelubiprofen preparations. After one-step liquid-liquid extraction (LLE) using methyl tert-butyl ether (MTBE), pelubiprofen, M-D, and tolbutamide (the internal standard, IS) were eluted from a Capcellpak C18 ACR column using a gradient mobile phase consisting of 0.1% formic acid in water and acetonitrile at a flow rate 0.35mL/min. The achieved lower limits of quantitation (LLOQ) of pelubiprofen and M-D were both 15ng/mL (S/N>10) and the standard calibration curves for pelubiprofen and M-D were linear (correlation coefficients >0.99) over the studied concentration range (15-2000ng/mL). Intra- and inter-day precisions were within 7.62% for all analytes and the deviation of assay accuracies was within ±13.23%. The developed method was successfully applied to a pharmacokinetic study of pelubiprofen in healthy Korean male volunteers.

[The association between the therapeutic agent and the compliance of the patients with inflammatory bowel diseases].

BACKGROUND/AIMS: Adherence of the patients with inflammatory bowel diseases is important to maintain the remission. However, the patients do not always keep their appointments for treatment. The aim of this study was to investigate the clinical factors associated with adherence of patients in terms of appointment keeping. METHODS: A total of 73 subjects were retrospectively investigated from September 2005 to January 2012 at Dongguk University Ilsan Hospital (Goyang, Korea). We reviewed medical records including the age, sex, residence, medications, the disease activity, and the rate of keeping the date. A punctual visit was defined as outpatient visit on the scheduled date ±7 days. Punctual patients for the visit were defined as their punctual visit rates exceed 90%. RESULTS: Male to female ratio was 2.4:1. Mean age was 41.5±15.4 years (range, 20 to 78 years). Ulcerative colitis was 53 cases (72.6%) and Crohn's disease was 20 cases (27.4%). Mean duration of disease was 42.0±41.6 months (range, 4 to 226 months). Mean puntual visit rate was 86.7±16.0% (range, 27 to 100). Thirty-eight patients (52.1%) were punctual patients for the visit. Azathioprine/6-mercaptopurine treatment was associated with punctual patients for the visit (odd ratio, 3.19; 95% confidence interval, 1.12 to 9.09; p=0.03). However, other clinical factors did not influence the punctual visit rates. CONCLUSIONS: Our study demonstrated that the use of azathioprine/6-mercaptopurine was associated with keeping the appointment for meeting the doctor. Further prospective study would be necessary.

Relative bioavailability of levodropropizine 60 mg capsule and syrup formulations in healthy male Korean volunteers: a singledose, randomized-sequence, open-label, two-way crossover study.

BACKGROUND: Levodropropizine is an oral non-opioid anti-tussive drug used in treatment of cough. A new generic 60 mg capsule formulation of levodropropizine has recently been developed. OBJECTIVES: The aim of this study was to assess the pharmacokinetics and bioequivalence of the test (capsule) formulation and reference (syrup) formulation of levodropropizine (60 mg) in healthy, fasted, male Korean volunteers. METHODS: This was a single-dose, randomized sequence, open-label, 2-period crossover study conducted in healthy male Korean volunteers in the fasted state at Kyung Hee University Medical Center (Seoul, Republic of Korea). A single oral dose of the test or reference formulation was followed by a 1-week washout period, after which subjects received the alternative formulation. Blood samples were collected at 0 (predose), 0.17, 0.33, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 8, and 12 hours after study drug administration. Plasma concentration of levodropropizine was determined using a validated liquid chromatography tandem mass spectrometry (LCMS/ MS) method. The formulations were considered bioequivalent if the 90% CIs for C(max), AUC(0-12h) and AUC(0-∞) were within the predetermined bioequivalence range (80 - 125%, according to the guidelines of the Korea Food and Drug Administration (Korea FDA)). Tolerability was evaluated throughout the study based on vital sign measurements, laboratory analysis (blood biochemistry, hematology, hepatic function and urinalysis) and subject interviews concerning adverse events (AEs). RESULTS: A total of 36 male Korean subjects (mean (SD) age, 23.9 (2.4) years (range 19 - 30 years); height, 176.2 (6.1) cm (range 161 - 190 cm); weight, 69.8 (9.1) kg (range 54.0 - 92.2 kg); body mass index, 22.4 (2.1) kg/m2 (range 19.1 - 28.3 kg/m2)) was enrolled and completed the study. The mean values for C(max), t(max), AUC(0-12h), and AUC(0-∞) with the test formulation of levodropropizine were 331.51 ng/ml, 0.60 hours, 784.32 ng×h/ml, and 825.82 ng×h/ml, respectively; for the reference formulation, the values were 332.81 ng/ml, 0.44 hours, 726.46 ng×h/ml, and 769.46 ng×h/ ml, respectively. The 90% CIs for the logtransformed ratios of C(max) (92.74 - 111.24), AUC(0-12h) (104.31 - 113.67) and AUC(0-∞) (103.87 - 113.57) were within the predetermined range for the assumption of bioequivalence. No serious adverse events were reported. CONCLUSIONS: This single-dose (60 mg) study found that the test (capsule) and reference (syrup) formulations of levodropropizine met the regulatory criterion for assuming bioequivalence in these healthy, fasted, male Korean subjects. Both formulations were well tolerated in the population studied. Korea FDA registration number: BED-1784.

Rapid and sensitive LC-MS/MS method for determination of megestrol acetate in human plasma: application to a human pharmacokinetic study.

A rapid, simple and fully validated LC-MS/MS method was developed and validated for the determination of megestrol acetate in human plasma using tolbutamide as an internal standard (IS) after one-step liquid-liquid extraction with methyl-tert-butyl-ether. Detection was performed using electrospray ionization in positive ion multiple reaction monitoring mode by monitoring the transitions m/z 385.5 → 267.1 for megestrol acetate and m/z 271.4 → 155.1 for IS. Chromatographic separation was performed on a YMC Hydrosphere C18 column with an isocratic mobile phase, which consisted of 10 mm ammonium formate buffer (adjusted to pH 5.0 with formic acid)-methanol (60:40, v/v) at a flow rate of 0.4 mL/min. The achieved lower limit of quantitation (LLOQ) was 1 ng/mL (signal-to-noise ratio > 10) and the standard calibration curve for megestrol acetate was linear (r > 0.99) over the studied concentration range (1-2000 ng/mL). The proposed method was fully validated by determining its specificity, linearity, LLOQ, intra- and inter-day precision and accuracy, recovery, matrix effect and stability. The validated LC-MS/MS method was successfully applied for the evaluation of pharmacokinetic parameters of megestrol acetate after oral administration of a single dose 800 mg of megestrol acetate (Megace™) to five healthy Korean male volunteers under fed conditions.

Characteristics of type 2 diabetes in terms of insulin resistance in Korea.

The aim of this study was to assess the implications of insulin resistance on the clinical and biochemical profiles of Korean type 2 diabetic patients. 122 patients with type 2 diabetes underwent a short insulin tolerance test to assess insulin resistance. Subjects were classified in tertiles according to ISI (insulin sensitivity index), and the tertile I (the insulin- resistant group) and tertile III (the insulin-sensitive group) clinical and biochemical parameters were compared. Age, waist circumference (WC), systolic blood pressure (SBP), HbA1c, body fat content, and fasting plasma glucose were significantly higher in tertile I than tertile III (all p < 0.05). The frequency of hypertension and family history of cerebrovascular disease (CVD) were greater in tertile I than III (p < 0.05). To evaluate the factors affecting ISI, multiple regression was performed, and age, WC, SBP, HbA1c, and body fat content were found to be independently related to insulin resistance (p < 0.05). Old age, hypertension, central obesity, and poor glycemic control were identified as clinical parameters of insulin resistance in Korean type 2 diabetic patients.