Heterogeneity of early-onset and ketosis-resistant diabetes in Korean subjects--is it possible to determine cut-off age of early-onset type 2 diabetes?

OBJECTIVE: To investigate the heterogeneity of early-onset and ketosis-resistant diabetes and to define a not-arbitrary cut-off age for early-onset diabetes based on its clinical and metabolic characteristics, and diabetes complications. METHODS: We classified 1015 early-onset diabetes subjects aged 21-40 into four groups (group I, age at diagnosis 21-25 years; group II, 26-30; group III, 31-35; group IV, 36-40). Familial and diabetic history, statue of insulin secretion, metabolic parameters, and diabetes complications were analyzed. RESULTS: No significant difference in family history or the rate of diabetic complication was found in the four groups. Subjects with a 21 to a 25-year-old diabetes onset had the lowest serum C-peptide levels, with 50% of the cumulative 24-h urine C-peptide levels of the other three groups (p<0.0001). This group also had the lowest prevalence of hyperlipidemia and arterial hypertension (p<0.01 and <0.0001, respectively). Group III was found to have a higher prevalence of insulin insufficiency and hypertension than group IV. CONCLUSION: Our data based on insulin secretory function and metabolic factors might suggest that a cut-off age of 26 years might be warranted in Korean patients. Korean early-onset type 2 diabetes patients tend to be non-obese and insulin secretory dysfunction.

Exopolysaccharide biosynthesis genes required for social motility in Myxococcus xanthus.

Social (S)-motility in Myxococcus xanthus is a flagellum-independent gliding motility system that allows bacteria to move in groups on solid surfaces. S-motility has been shown to require type IV pili (TFP), exopolysaccharide (EPS; a component of fibrils) and lipopolysaccharide (LPS). Previously, information concerning EPS biogenesis in M. xanthus was lacking. In this study, we screened 5000 randomly mutagenized colonies for defects in S-motility and EPS and identified two genetic regions essential for EPS biogenesis: the EPS synthesis (eps) region and the EPS-associated (eas) region. Mutants with insertions in the eps and eas regions were defective in S-motility and fruiting body formation. These mutants failed to bind the dye calcofluor white, indicating that they lacked EPS; however, they retained normal TFP and LPS. Analysis of the eps locus showed several open reading frames (ORFs) that encode homologues to glycosyltransferases, glucanases and EPS transporters as well as regulatory proteins; the eas locus contains two ORFs: one exhibits homology to hypothetical proteins with a conserved domain of unknown function and the other displays no apparent homology to other proteins in the database. Further genetic mutagenesis analysis indicates that the whole eps region is involved in the biosynthesis of fibrils and fibril EPS. The operon at the proximal end of the eps region was analysed by generating in-frame deletion mutations. These mutants showed varying degrees of defects in the bacterium's ability to produce EPS or perform EPS-related functions, confirming the involvement of these genes in M. xanthus EPS biogenesis.