Effects of Glycerophospholipids on Ceramide Kinase Activity: Cardiolipin-Affected Cellular Formation of Ceramide-1-phosphate.

Ceramide kinase (CerK) and ceramide-1-phosphate (C1P) are involved in various cellular functions, while regulation of the enzyme activity has not been well elucidated. We herein investigated the effects of several glycerophospholipids on human recombinant CerK activity with CaCl and MgCl by measuring the formation of fluorescent labeled C1P in vitro. CerK activities were 44.

Characterization of chimeric and mutated isocitrate lyases of a mesophilic nitrogen-fixing bacterium, Azotobacter vinelandii, and a psychrophilic bacterium, Colwellia maris.

Chimeric enzymes between a cold-adapted isocitrate lyase (ICL) of a psychrophilic bacterium, Colwellia maris, (CmICL) and a mesophilic ICL of a nitrogen-fixing bacterium, Azotobacter vinelandii, (AvICL) were constructed by dividing the ICL genes into four regions of almost equal length and exchanging regions in various combinations. The chimeric ICL, which was replaced C-terminal region 4 of AvICL by the corresponding region of CmICL, showed much lower specific activity and lower optimum temperature and thermostability for activity than wild-type AvICL, indicating that region 4 is involved in its thermal properties. Furthermore, mutual substitution between the Met501 residue in region 4 of CmICL and the corresponding Ile504 residue of AvICL influenced the temperature dependence of their activities, suggesting that these amino acid residues are important to the respective mesophilic and cold-adapted properties of AvICL and CmICL.

Regulation of alkaline ceramidase activity by the c-Src-mediated pathway.

Ceramidase hydrolyzes ceramide to fatty acids and sphingosine, and sphingosine is then converted to sphingosine-1-phosphate. Ceramide and sphingosine-1-phosphate act as signaling molecules. Although stimuli coupling to protein kinases-dependent systems have been shown to regulate ceramidase activity, the exact role of c-Src-mediated signal has not been elucidated.

Basal cell adenocarcinomas of the submandibular and parotid glands recognized simultaneously report of a case.

Basal cell adenocarcinomas (BCAC) of the major salivary glands are rare tumors. We experienced a case of BCACs that were recognized simultaneously in the submandibular and parotid glands. The case like this has not been reported previously.

The clinical application of an ATP assay to predict the chemosensitivity of gastric cancer.

The chemosensitivity of human xenografts in nude mice and fresh surgical specimens of gastric cancer was evaluated in vitro using the ATP assay and the MTT assay. The in vitro sensitivity of 6 human xenografts was detected by the ATP assay and compared with the in vivo sensitivity of the xenografts in nude mouse. The assay showed a 56.