Anti-diabetic properties of different fractions of Korean red ginseng.

ETHNOPHARMACOLOGICAL RELEVANCE: Korean red ginseng (KRG) has been traditionally used to treat diabetes. Ginsenosides are considered as the major bioactive components mediating anti-diabetic effects of KRG. However, considering that ginsenosides account for only about 3-4% of ginsengs, other fractions of KRG may also carry potential anti-diabetic effects. There is no study reporting the differentiated effects of ginsenosides (Spn) and non-saponin fractions (NSpn) of KRG on glycemic control. AIM OF THE STUDY: We investigated the effects of KRG, Spn, and NSpn on the indications of glycemic control and sought to elucidate physiological factors contributing their effects. MATERIALS AND METHODS: Human T2DM mimicking Nagoya-Shibata-Yasuda (NSY/hos) mice were given KRG, Spn, or NSpn admixed in rodent diet at 200 mg/kg/day for 24 weeks. Glycemic and obesity indications, blood lipid profile, systematic and local oxidative stress markers in metabolically important organs, and systematic inflammatory markers were assessed. Molecular assessments associated with glycemic control in liver and skeletal muscle were further performed. RESULTS: KRG attenuated deterioration in glucose homeostasis as evidenced by significantly lower fasting blood glucose from 22nd week and AUC during GTT at the end of the experiment compare to control. Spn enhanced insulin secretion in response to glucose stimulation and reduced protein level of glycogen phosphorylase in liver. On the other hand, NSpn ameliorated oxidative stress and inflammation. Some beneficial effects of Spn and NSpn were reflected in KRG treated mice. KRG also attenuated the accumulation of malondialdehyde in skeletal muscle and, accordingly, enhanced insulin responsiveness compare to control. CONCLUSION: Anti-diabetic properties of KRG are not solely determined by the contents of ginsenosides but the harmonic functions of its different fractions.

Characterization of pncA mutations in pyrazinamide-resistant Mycobacterium tuberculosis isolates from Korea and analysis of the correlation between the mutations and pyrazinamidase activity.

To investigate the effect of natural pyrazinamidase (PncA) mutations on protein function, we analyzed expression and PncA activity of eight pncA point mutants identified in nineteen pyrazinamide-resistant Mycobacterium tuberculosis clinical isolates. Among them, two mutants (Y99D and T135P) showed high expression level and solubility comparable to those of the wild-type PncA protein, two (K48E and G97D) displayed low expression level and solubility, and four (C14R, H51P, W68S, and A146V) were insoluble. Interestingly, when possible structural effects of these mutations were predicted by the CUPSAT program based on the proposed three-dimensional structure of M. tuberculosis PncA, only two highly soluble mutant proteins (Y99D and T135P) were predicted to be stabilizing and have favorable torsion angles. However, the others exhibiting either low solubility or precipitation were foreseen to be destabilizing and/or have unfavorable torsion angles, suggesting that the alterations could interfere with proper protein folding, thereby decreasing or depleting protein solubility. A PncA activity assay demonstrated that two mutants (G97D and T135P) showed virtually no activity, but two other mutants (K48E and Y99D) exhibited wild-type activity, indicating that the PncA residues (Cys14, His51, Trp68, Gly97, Thr135, and Ala146) may be important for PncA activity and/or proper protein folding.

Simple and rapid discrimination of embB codon 306 mutations in Mycobacterium tuberculosis clinical isolates by a real-time PCR assay using an LNA-TaqMan probe.

Single nucleotide polymorphisms in the codon 306 of embB gene are most frequently reported in ethambutol-resistant Mycobacterium tuberculosis clinical isolates. Here, we report a simple and rapid real-time PCR assay using a locked nucleic acid (LNA)-TaqMan probe for discriminating the embB306 mutations. The use of a 15-bp chimeric LNA/DNA probe led to a relatively higher level of sensitivity and fluorescence signal in the wild-type embB306 ATG codon. Therefore, the mutant alleles were easily distinguishable from the wild-type allele by their distinctive amplification curve shapes without a melting analysis of the PCR product. This system was fast and less than 0.1 pg of genomic DNA per reaction was needed for detection. Because the results from this real-time assay were absolutely consistent with those from DNA sequencing, it can be effectively applied as a simple and rapid method for primary screening of embB306 mutations that occur frequently in ethambutol-resistant and/or multidrug-resistant M. tuberculosis isolates.

Molecular characterization of drug-resistant and -susceptible Mycobacterium tuberculosis isolated from patients with tuberculosis in Korea.

We investigated the causal relationship between genotype and phenotype of drug-resistant Mycobacterium tuberculosis isolates obtained from patients with pulmonary tuberculosis (TB) in Korea. Of 80 isolates tested, 17, 20, 1, and 7 isolates were mono-resistant to ethambutol (EMB), isoniazid (INH), pyrazinamide (PZA), and rifampicin (RFP), respectively, and 31 isolates (38.8%) were multidrug-resistant (MDR). Sequencing analysis showed that 78% (32/41) of RFP-resistant strains had mutations in the rifampicin resistance-determining region (RRDR) of rpoB, and the mutation at rpoB531 (59.4%) was most abundant. In 52 INH-resistant strains, mutations were found mostly at C-15T (n = 21, 40.4%) in the inhA promoter region as well as at katG315 (n = 12, 23.1%). Mutations at embB306 were mostly found in 26.7% (12/45) of EMB-resistant isolates. New mutations found here in MDR isolates include rpoB523 (Gly523Glu) and embB319 (Tyr319Ser). Consequently, mutations in the rpoB531, C-15T in the inhA promoter region, embB306, and katG315 would be a useful marker for rapid detection of MDR M. tuberculosis isolates in Korea.

Molecular cloning, purification, and characterization of a superoxide dismutase from a fast-growing Mycobacterium sp. Strain JC1 DSM 3803.

A cytosolic superoxide dismutase (SOD) was purified and characterized from a fast-growing Mycobacterium sp. strain JC1 DSM 3803 grown on methanol. The native molecular weight of the purified SOD was estimated to be 48 kDa. SDS-PAGE revealed a subunit of 23 kDa, indicating that the enzyme is a homodimer. The enzyme activity was inhibited by H(2)O(2) and azide. The purified SOD contained 1.12 and 0.56 g-atom of Mn and Fe per mol of enzyme, respectively, suggesting that it may be a Fe/Mn cambialistic SOD. The apo-SOD reconstitution study revealed that Mn salts were more specific than Fe salts in the SOD activity. The gene encoding the SOD was identified from the JC1 cosmid genomic library by PCR screening protocol. The cloned gene, sodA, had an open reading frame (ORF) of 624 nt, encoding a protein with a calculated molecular weight of 22,930 Da and pi of 5.33. The deduced SodA sequence exhibited 97.6% identity with that of Mycobacterium fortuitum Mn-SOD and clustered with other mycobacterial Mn-SODs. A webtool analysis on the basis of SOD sequence and structure homologies predicted the SOD as a tetrameric Mn-SOD, suggesting that the protein is a dimeric Mn-SOD having tetramer-specific sequence and structure characteristics.

Cloning, expression and characterization of the catalase-peroxidase (KatG) gene from a fast-growing Mycobacterium sp. strain JC1 DSM 3803.

The gene encoding a catalase-peroxidase (KatG) was cloned from chromosomal DNA of a fast-growing Mycobacterium sp. strain JC1 DSM 3803. The nucleotide sequence of a 5.7 kb EcoRI fragment containing the katG and its flanking regions was determined. The fragment (5,706 bps) contained two complete open reading frames (ORFs) encoding putative ferric uptake regulator A (FurA) and KatG proteins. The cloned gene, katG, had an ORF of 2241 nt, encoding a protein with calculated molecular mass of 81,748 Da. The furA was located in the upstream of the katG with the same transcriptional direction and there was a 38 bp gap space between them. The deduced KatG and FurA protein sequences showed significant homologies to KatG2 and Fur2 of Mycobacterium smegmatis and clustered with other mycobacterial KatG and Fur-like proteins in phylogenetic trees, respectively. The recombinant KatG overproduced in Escherichia coli was nearly indistinguishable from the native JC1 catalase-peroxidase in enzymatic properties and also possessed the resistance to organic solvents, indicating that the cloned katG truly encodes the Mycobacterium sp. JC1 catalase-peroxidase. Difference spectroscopy revealed Mn(II) binding near the haem of the KatG. Transcript analysis of the furA-katG using RT-PCR suggests that the katG is independently transcribed from the furA.

Association of abdominal obesity with atherosclerosis in type 2 diabetes mellitus (T2DM) in Korea.

The aim of this study was to investigate the relationship between obesity, insulin resistance and atherosclerosis in type 2 diabetes mellitus (T2DM) patients. Total 530 patients with T2DM were included. To evaluate the severity of atherosclerosis, we measured the coronary artery calcification (CAC) score, intima-media thickness (IMT) of the common carotid artery, and the ankle-brachial pressure index (ABPI). Subjects were classified according to body mass index (BMI), a marker of general obesity, and waist-to-hip ratio (WHR), a marker of regional obesity. The insulin sensitivity index (ISI) was measured by the short insulin tolerance test. All subjects were classified into four groups, according to BMI: the under-weight group, the normal-weight (NW) group, the over-weight (OW) group, and the obese (OB) group. WHR and systolic blood pressure, triglycerides (TG), HDL-cholesterol (HDLC), free fatty acids (FFA), fibrinogen, and fasting c-peptide levels were significantly different between BMI groups. TG, HDL-C, FFA, fibrinogen and ISI were significantly different between patients with and without abdominal obesity. In the OW group as well as in the NW group, carotid IMT, ABPI and CAC score were significantly different between patients with and without abdominal obesity. This study indicates that abdominal obesity was associated with atherosclerosis in T2DM patients.

The relation between birth weight and insulin resistance in Korean adolescents.

Low birth weight is associated with insulin resistance and type 2 diabetes in adults. The fetal programming hypothesis has shown that insulin resistance and its associated metabolic disturbances result from a poor gestational environment, for which low birth weight is a surrogate. An at-home questionnaire survey was performed on 660 middle school students (12-15 years) in Seoul, Korea, and 152 cases were randomly selected based on their birth weight. Subjects were divided into three groups according to birth weight. We recorded their birth weight and measured their current anthropometric data, blood pressure, lipid profile, HOMA-IR, and HOMA-beta, and compared these parameters among the groups. The relation of birth weight to physiological characteristics in adolescence was examined. Systolic blood pressure, lipid profiles, and fasting plasma glucose, HOMA-beta were not significantly different among the groups, but diastolic blood pressure was lower in the third tertile. Insulin, C-peptide, and HOMA-IR were higher in the lower birth weight tertile. After adjustment for confounding factors, birth weight was inversely related to diastolic blood pressure, insulin, C-peptide, and HOMA-IR. We conclude that low birth weight may predict the risk of the insulin resistance and its progression over age, and that adequate gestational nutrition is therefore necessary to prevent low birth weight.

Characterization of Sclerotinia sclerotiorum Isolated from Paprika.

A fungal isolate collected from infected paprika (Capsicum annuum var. grossum) was characterized as Sclerotinia sclerotiorum based on its ability of sclerotium formation, physiological and molecular properties. When the isolate was grown on potato dextrose agar, oatmeal agar, and malt extract agar, it grew most well on PDA. Optimal temperature and pH for its growth were 25℃ and pH 7, respectively. The fungal isolate produced sclerotia on PDA within 10 days, and the color and shape of the sclerotia were similar to those of S. sclerotiorum . The ITS rDNA regions including ITS1 and ITS2 and 5.8S sequences were amplified using ITS1F and ITS4 primers from the genomic DNAs of the paprika isolate and other known pathogenic S. sclerotiorum isolated from different crops in Korea, and their nucleotide sequences were determined. Sequence comparison analysis showed the ITS rDNA of the paprika isolate shares 100% sequence identity with those of S. sclerotiorum isolated from red pepper, lettuce and a S. sclerotiorum isolate registered in GenBank DNA database. Neighbor joining analysis based on the ITS rDNA sequence revealed the paprika isolate has very close phylogenetic relationships with known Sclerotinia sclerotiorum isolates. This is the first report that S. sclerotiorum has been found associated with paprika rot in paprika growing countries.

A Phase II study of capecitabine combined with gemcitabine in patients with advanced gallbladder carcinoma.

Capecitabine and gemcitabine are used in the treatment of a variety of solid tumors including pancreatic and biliary tract carcinomas. The authors evaluated survival, response, and toxicity associated with using a combination of capecitabine and gemcitabine to treat patients with unresectable or metastatic gallbladder adenocarcinoma (GBC). Eligible patients had histologically- or cytologically-confirmed GBC, no prior systemic therapy with capecitabine or gemcitabine, Karnofsky Performance Status 70%, serum total bilirubin up to three times normal, and measurable disease. Treatment consisted of gemcitabine 1000 mg/m2 IV on Days 1 and 8 concurrent with administration of capecitabine 1000 mg/m2 PO BID on Days 1 through 14, on a 3-week cycle. Tumor response was assessed by the response evaluation criteria in solid tumors (RECIST criteria) and survival was calculated from initiation of CapGem therapy. A total of 24 patients were enrolled. Median age at the time of diagnosis was 62 years (range, 41-78 years). Fourteen patients had undergone prior surgery. Results showed that eight patients achieved partial response (33%) with an additional 10 patients achieving stable disease (42%). The overall median time to disease progression was 6.0 months (95% CI, 3.8-8.1 months) and overall survival was 16 months (95% CI, 13.8-18.3 months). The one-year survival rate was 58%. No Grade 4 toxicity was seen. Transient Grade 3 neutropenia/ thrombocytopenia and manageable nausea, hand-foot syndrome and anorexia were the most common toxicities. Our study shows that CapGem is an active and well-tolerated chemotherapy regimen in patients with advanced GBC.