Human BST-1, a bone marrow stromal cell surface molecule, is a GPI-anchored protein that facilitates the growth of pre-B cells. The deduced amino acid sequences of human and mouse BST-1 show around 30% homology with those of CD38 and Aptysia ADP ribosyl cyclase.Therefore, like CD38, BST-1 might possess ADP ribosyl cyclase activity. Here, we report the establishment of a stable transformant CHO cell line, which secretes truncated human soluble BST-1, and show that purified soluble BST-1 displays both ADP ribosyl cyclase and cADPR hydrolase activities.

Photoluminescence enhancement, photoetching and photostability of CdS nanocrystals were investigated under light irradiation. Strongly photoluminescent nanocrystals were obtained when the nanocrystal was weakly photoexcited in an aqueous solution at pH = 11 in the presence of oxygen. With the support of XPS measurements, the following photoactivation mechanism is proposed: Cd(2+) ions are released from the CdS surface owing to slow photocorrosion in the presence of oxygen, and Cd-OH bond formation occurs on the CdS surface under the alkaline conditions, removing the surface trap states. The wavelength of the irradiating light and the pH of the solution were determined as key parameters for nanocrystal surface modification. For the stability measurements the nanocrystals were extracted with an ammonium salt in a non-polar solvent. The photoluminescence quantum yield for the nanocrystals in the non-polar phase reached approximately 30%. The extracted nanocrystals were remarkably stable even under UV light irradiation, and the photoluminescence intensity was maintained for several months.

Cachexia often causes deterioration in the quality of life in cancer patients; however, its mechanism remains poorly understood. Cachexia has often been observed in experimental animals with bone metastases, and parathyroid hormonerelated protein (PTHrP) plays an important role in the formation of such metastases. We therefore investigated the possible involvement of PTHrP in an experimental cachexia model using human lung-cancer cells (HARA-B Cachexia often accompanies various cancers in advanced stages and tends to deteriorate the quality of life in such patients while also affecting the survival period and/or response to chemotherapy. 1 As a result, understanding the mechanism of cancer cachexia could lead to the development of appropriate types of therapeutic intervention for these patients; however, its mechanism remains poorly understood. Cachexia is thought to be induced by soluble factors produced and released from hematopoietic cells and/or cancer cells. Several cytokines, i.e., TNF, 2,3 IL-1, 4 IFN-␥, 5 IL-6, 6,7 leukemia inhibitory factor (LIF) 8 and TGF-␤, 9 induce cachexia in different models. However, exactly how these cytokines are involved in the mechanism of cachexia induction remains to be elucidated.In the present report, we describe an experimental cachexia model using a human lung cancer-derived cell line (HARA-B), in which parathyroid hormone-related protein (PTHrP) mRNA is strongly expressed. Using this model, the involvement of PTHrP in the mechanism of cachexia induction was investigated. MATERIAL AND METHODS CellsHARA-B cells were established from a bone lesion formed after the intracardiac inoculation of HARA cells. 10 Cells were maintained in RPMI-1640 supplemented with 10% FBS at 37°C in humidified atmosphere of 5% CO 2 . Cells were grown as a monolayer culture in a flask, and a single-cell suspension of cells was obtained by trypsin treatment. MiceMale 5-week-old BALB/c nu/nu mice (Nippon CLEA, Tokyo, Japan), kept in a specific pathogen-free environment, were used. Measurement of cachexic parametersFor the in vivo experiment on cachexia, a single-cell suspension of HARA-B cells (5 ϫ 10 6 ) was inoculated s.c. into the right flank of nude mice. Body weight and tumor size [length (a) and width (b)] were thereafter measured periodically. Then, mice were killed 8 weeks after cell inoculation. At this time, blood was collected from the heart and the epididymal adipose tissue and gastrocnemius muscle were weighed. Serum samples, obtained after centrifugation, were stored at -30°C until serum glucose, calcium and PTHrP levels were determined. Serum glucose and calcium levels were measured using the enzyme-reaction method (glucose C⌸ test; Wako, Osaka, Japan) and a color-chelate reaction method (Calcium C-test, Wako), respectively. The serum PTHrP level was measured using a radioimmunoassay kit specific for the C-terminal portion of PTHrP (Daiichi, Tokyo, Japan). The serum mouse IL-6 level was measured using an ELISA kit (Endogen, Woburn, MA). Tumor weight was estimated by the formula (ab 2...

Most opsins are G protein-coupled receptors that utilize retinal both as a ligand and as a chromophore. Opsins’ main established mechanism is light-triggered activation through retinal 11-cis-to-all-trans photoisomerization. Here we report a vertebrate non-visual opsin that functions as a Gi-coupled retinal receptor that is deactivated by light and can thermally self-regenerate. This opsin, Opn5L1, binds exclusively to all-trans-retinal. More interestingly, the light-induced deactivation through retinal trans-to-cis isomerization is followed by formation of a covalent adduct between retinal and a nearby cysteine, which breaks the retinal-conjugated double bond system, probably at the C11 position, resulting in thermal re-isomerization to all-trans-retinal. Thus, Opn5L1 acts as a reverse photoreceptor. We conclude that, like vertebrate rhodopsin, Opn5L1 is a unidirectional optical switch optimized from an ancestral bidirectional optical switch, such as invertebrate rhodopsin, to increase the S/N ratio of the signal transduction, although the direction of optimization is opposite to that of vertebrate rhodopsin.

No abstract