A growth inhibitor, 2-thioxothiazolidine-4-carboxylic acid from sakurajima radish seedlings

A new growth inhibitor isolated from an acetone extract of light-exposed seedlings of Sakurajima radish, was characterized as 2-thioxothiazolidine-4-ca     

Subunits of RNA polymerase in function and structure: VI. Sequence of the assembly in vitro of Escherichia coli RNA polymerase

Detailed analysis of the assembly in vitro of Escherichia coli RNA polymerase reveals that core enzyme subunits are assembled in the following sequence: $\text{2 α → α}{}_2\text{→}\text{β}\text{α}{}_2\text{β}\text{→}\text{β′}\text{α}{}_2\text{ββ′}$(premature core) → E (active core). Activation of the premature core enzyme, the rate-limiting step in this sequence, can be achieved in three different ways: self-reactivation, sigma subunit (σ or σ′)-promoted reactivation, and DNA-promoted reactivation.Although there has been disagreement on the enhancement of core enzyme maturation by sigma subunit or DNA, the discrepancy is resolved by the present finding that the premature core alone can be activated in the presence of high concentrations of salt or glycerol, whereas at a salt concentration as low as that in vivo, sigma subunit or DNA is required for maximum activation. However, the question remains unsolved as to which of the three ways operates in the in vivo process of RNA polymerase formation.     

Intravascular insulin gene delivery as potential therapeutic intervention in diabetes mellitus

We assessed therapeutic potential of intravascular insulin gene delivery in a diabetic murine model. The rat proinsulin-1 gene cDNA engineered to harbor furin consensus cleavage sequences was inserted into EBV-based plasmid vectors that contained CAG promoter or multimerized rat insulin promoter (RIP). Normal or streptozotocin (STZ)-induced diabetic mice were given an injection of the plasmids via the tail vein under high pressure. Transfection of the CAG-proinsulin construct markedly improved hyperglycemia of diabetic mice, accompanied by a considerable increase in serum insulin concentrations. Although the RIP-plasmid failed to reduce fasting blood glucose, the glucose tolerance test and RT-PCR analysis revealed that insulin production was regulated in the liver in a blood glucose level-dependent manner. The present results suggest a potential therapeutic means of controlling DM.     

Quantification of hydroxyproline in small amounts of skin tissue using isocratic high performance liquid chromatography with NBD-F as fluorogenic reagent

In order to determine the collagen content of small amounts of skin tissue, we developed a new, simple and highly sensitive method of measuring the quantity of hydroxyproline (Hyp) using isocratic high performance liquid chromatography (HPLC) with a fluorogenic agent, 7-fluoro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-F). The recovery rate of Hyp and reproducibility of the assay were high, and the test was sensitive enough to detect Hyp in less than 1 mg of skin tissue. This method is clinically useful for ensuring accurate diagnosis and for monitoring specific skin conditions using small human skin samples collected in biopsies.