No abstract

Apoptotic cell death of murine leukemia cells induced by E. coli L-asparaginase was studied. Deprivation of L-asparagine from the culture of L5178Y cells by L-asparaginase caused the fragmentation of chromosomal DNA of the leukemia cells within 24 h. Prior to the degradation of DNA, cell cycles of L5178Y cells were found to be arrested in G1 phase, and evidence of the DNA strand breaks was initially observed in G1 phase cells as early as 8 h after the asparaginase treatment. Therefore, apoptosis of leukemia cells induced by L--asparaginase is an event that is associated with the cell cycle arrest in G1 phase.

No abstract

Chlorophyll a was adsorbed to a synthetic smectite intercalated by poly(vinylpyrrolidone) (PVP) to form the chlorophyll-PVP-smectite conjugate (Chl-PVP-SME) having an absorption maximum at 677 nm. The conjugate was found to be stable toward light illumination in comparison with chlorophyll-smectite, chlorophyll-PVP, and free chlorophyll a. Chl-PVP-SME had a photoinduced activity for catalyzing the reduction of methyl viologen. Furthermore, the evolution of hydrogen gas was observed when an aqueous suspension containing Chl-PVP-SME, methyl viologen (an electron carrier), 2-mercaptoethanol (an electron donor), and hydrogenase was illuminated by visible light.