The adipocyte-derived hormone adiponectin has been shown to play important roles in the regulation of energy homeostasis and insulin sensitivity. In this study, we analyzed globular domain adiponectin (gAd) transgenic (Tg) mice crossed with leptin-deficient ob/ob or apoE-deficient mice. Interestingly, despite an unexpected similar body weight, gAd Tg ob/ob mice showed amelioration of insulin resistance and ␤-cell degranulation as well as diabetes, indicating that globular adiponectin and leptin appeared to have both distinct and overlapping functions. Amelioration of diabetes and insulin resistance was associated with increased expression of molecules involved in fatty acid oxidation such as acyl-CoA oxidase, and molecules involved in energy dissipation such as uncoupling proteins 2 and 3 and increased fatty acid oxidation in skeletal muscle of gAd Tg ob/ob mice. Moreover, despite similar plasma glucose and lipid levels on an apoE-deficient background, gAd Tg apoE-deficient mice showed amelioration of atherosclerosis, which was associated with decreased expression of class A scavenger receptor and tumor necrosis factor ␣. This is the first demonstration that globular adiponectin can protect against atherosclerosis in vivo.In conclusion, replenishment of globular adiponectin may provide a novel treatment modality for both type 2 diabetes and atherosclerosis.

In Escherichia coli, the ATP-DnaA protein initiates chromosomal replication. After the DNA polymerase III holoenzyme is loaded on to DNA, DnaA-bound ATP is hydrolysed in a manner depending on Hda protein and the DNA-loaded form of the DNA polymerase III sliding clamp subunit, which yields ADP-DnaA, an inactivated form for initiation. This regulatory DnaA-inactivation represses extra initiation events. In this study, in vitro replication intermediates and structured DNA mimicking replicational intermediates were first used to identify structural prerequisites in the process of DnaA-ATP hydrolysis. Unlike duplex DNA loaded with sliding clamps, primer RNA-DNA heteroduplexes loaded with clamps were not associated with DnaA-ATP hydrolysis, and duplex DNA provided in trans did not rescue this defect. At least 40-bp duplex DNA is competent for the DnaA-ATP hydrolysis when a single clamp was loaded. The DnaA-ATP hydrolysis was inhibited when ATP-DnaA was tightly bound to a DnaA box-bearing oligonucleotide. These results imply that the DnaA-ATP hydrolysis involves the direct interaction of ATP-DnaA with duplex DNA flanking the sliding clamp. Furthermore, Hda protein formed a stable complex with the sliding clamp. Based on these, we suggest a mechanical basis in the DnaAinactivation that ATP-DnaA interacts with the Hda-clamp complex with the aid of DNA binding.

SummaryWe isolated and characterized a new gene related to the control of cell division regulation in Escherichia coli. At 30ЊC, the dnaAcos mutant causes over-replication of the chromosome, and colony formation is inhibited. We found that, at this temperature, the dnaAcos cells form filaments; therefore, septum formation is inhibited. This inhibition was independent of SfiA, an inhibitor of the septum-forming protein, FtsZ. To identify factors involved in this pathway of inhibition, we isolated seven multicopy suppressors for the cold-sensitive phenotype of the dnaAcos mutant. One of these proved to be a previously unknown gene, which we named cedA. This gene encoded a 12 kDa protein and resided at 38.9 min on the E. coli genome map. A multicopy supply of the cedA gene to the dnaAcos cells did not repress over-replication of the chromosome but did stimulate cell division of the host, the result being growth of cells with an abnormally elevated chromosomal copy number. Therefore, the expression level of the cedA gene seems to be important for inhibiting cell division of the dnaAcos mutant at 30ЊC. We propose that overreplication of the chromosome activates a pathway for inhibiting cell division and that the cedA gene modulates this division control. In the dnaA þ background, cedA also seems to affect cell division.

The DnaA protein, which initiates chromosomal replication in Escherichia coli, is negatively regulated by both the sliding clamp of DNA polymerase III holoenzyme and the IdaB protein. We have found that, when the amount of minichromosome is limited in an in vitro replication system, minichromosomal replication-stimulated hydrolysis of DnaA-bound ATP yields the ADP-bound inactive form. The number of sliding clamps formed during replication was at least five per minichromosome, which is 2.7-fold higher than the number formed during incubation without replication. These results support the notion that coupling of DnaA-ATP hydrolysis to DNA replication is the outcome of enhanced clamp formation. We have also found that the amino acid substitution R334H in DnaA severely inhibits the hydrolysis of bound ATP in vitro. Whereas ATP bound to wild-type DnaA is hydrolysed in a DNA-dependent intrinsic manner or in a sliding clamp-dependent manner, ATP bound to DnaA R334H protein was resistant to hydrolysis under the same conditions. This arginine residue may be located in the vicinity where ATP binds, and therefore may play an essential role in ATP hydrolysis. This residue is highly conserved among DnaA homologues and also in the Box VIII motif of the AAA+ protein family.

Although only 2 cases were surgically intervened with limited experience, the present novel LECS approach allowed a reliable, adequate resection of tumors located in the duodenum, with abbreviated operation times (156-179 versus 202-229 minutes), minimal bleeding, less postoperative stress imposed on the surgeons, and an uneventful postoperative course, compared to conventional surgical methods.