Porous Pellicle Formation of a Filamentous Bacterium, .

The bacterium Leptothrix cholodnii generates filaments encased in a sheath comprised of woven nanofibrils. In static liquid culture, moves toward the air-liquid interface, where it forms porous pellicles. Observations of aggregation at the interface reveal that clusters consisting of only a few bacteria primarily grow by netting free cells.

A naphthoquinone derivative, shikonin, has insulin-like actions by inhibiting both phosphatase and tensin homolog deleted on chromosome 10 and tyrosine phosphatases.

The 1,4-naphthoquinone derivative, shikonin, has been shown to increase glucose uptake by adipocytes and myocytes with minor effects on protein tyrosine phosphorylation in the cells (Biochem Biophys Res Commun 292:642-651, 2002). The present study was performed to examine the mechanism of this action of shikonin. Shikonin inhibited the phosphatidylinositol 3,4,5-triphosphate (PtdIns-3,4,5-P3) phosphatase activity of recombinant phosphatase and tensin homolog deleted on chromosome 10 (PTEN) with an IC50 value of 2.