Detection of Legionella pneumophila serogroup 1 antigen in respiratory samples using an immunochromatographic membrane test

The immunochromatographic membrane test (ICT) efficacy of Legionella antigen detection (Binax Now Legionella®) was evaluated using respiratory samples, including bronchial washings (44 cases) and sputum (128 cases), from suspected Legionella pneumonia patients. The ICT results using respiratory samples agreed well with isolation of L. pneumophila SG1 and ICT using urines.     

Elucidation of the role of activin in organogenesis using a multiple organ induction system with amphibian and mouse undifferentiated cells in vitro

Studies performed over the last century have clarified the mechanisms of organ and tissue formation. Mesoderm formation is one of the most important events in early body pattern determination during embryogenesis. In 1988, we found that activin A has mesoderm-inducing activity. As activin A could induce dorsal mesoderm formation, unlike fibroblast growth factor and bone morphogenetic protein, this factor was thought to be the molecular entity of the Spemann-Mangold organizer. Subsequently, the mechanisms of early embryogenesis have been clarified using molecular biological techniques, resulting in the identification of many genes that are involved in organ and tissue development. This finding that activin A could induce dorsal mesoderm formation spurred research into the application of agents that induce organs and tissues in vitro . In this regard, we have shown that many organ types can be induced by activin A in vitro . Moreover, we have found that other types of organs can be induced by changing the conditions of treatment. To date, more than 20 different types of tissues and organs have been successfully induced from Xenopus undifferentiated cells in vitro . In recent years, we have applied these protocols to mouse embryonic stem cells, and we have successfully induced several tissues, such as the pancreas and cardiomyocytes. We are also investigating how the pluripotency of undifferentiated stem cells is regulated. In this review, we summarize the current knowledge regarding activin as a mesoderm-inducing factor and its application for the induction of tissues and organs from undifferentiated cells. Moreover, we provide some examples of in vitro tissue differentiation from mouse embryonic stem cells, which may prove useful in regenerative medicine.     

Structure-based analysis reveals hydration changes induced by arginine hydrochloride

Arginine hydrochloride has been used to suppress protein aggregation during refolding and in various other applications. We investigated the structure of hen egg-white lysozyme (HEL) and solvent molecules in arginine hydrochloride solution by X-ray crystallography. Neither the backbone nor side-chain structure of HEL was altered by the presence of arginine hydrochloride. In addition, no stably bound arginine molecules were observed. The number of hydration water molecules, however, changed with the arginine hydrochloride concentration. We suggest that arginine hydrochloride suppresses protein aggregation by altering the hydration structure and the transient binding of arginine molecules that could not be observed.     

Reconstitution of bacteriorhodopsin into cyclic lipid vesicles

Bacteriorhodopsin (bR), a membrane protein that can generate a light-driven proton pump, was successfully reconstituted into vesicles composed of an artificial cyclic lipid that mimics archaeal membrane lipids. Unlike reconstituted bR in 1,2-dimyristoyl-sn-glycero-3-phosphocholine vesicles, the net topology and structure of bR molecules in cyclic lipid vesicles are identical to those in the native purple membrane of Halobacterium salinarum.     

Alterations in manganese, copper, and zinc contents, and intracellular status of the metal-containing superoxide dismutase in human mesothelioma cells

BACKGROUND AND AIM: Molecular diagnostics and therapeutics of human mesothelioma using disease-related markers present major challenges in clinical practice. To identify biochemical alternations that would be markers of human mesothelioma, we measured the intracellular steady-state levels of biologically important trace metals such as manganese (Mn), copper (Cu), and zinc (Zn) in a human mesothelial cell line, MeT-5A, and in five human mesothelioma cell lines (MSTO-211H, NCI-H226, NCI-H2052, NCI-H2452, ACC-MESO-1) by inductively coupled plasma-mass spectrometry (ICP-MS). We also aimed to investigate whether the alterations were related to the intracellular status of metal-containing superoxide dismutase (SOD). RESULTS: There were no significant differences in the contents of the trace metals among MeT-5A, MSTO-211H, and ACC-MESO-1 cells. However, each of the other three mesothelioma cell lines had a unique characteristic in terms of the intracellular amounts of the metals; NCI-H226 contained an extremely high level of Mn, an amount 7.3-fold higher than that in MeT-5A. NCI-H2052 had significantly higher amounts of Cu (3.4-fold) and Zn (1.3-fold) compared with MeT-5A. NCI-H2452 contained about 5.8-fold the amount of Cu and 2.5-fold that of Mn compared with MeT-5A. As for the intracellular levels of copper/zinc-SOD (Cu/Zn-SOD) and manganese-SOD (Mn-SOD), those of Cu/Zn-SOD were relatively unchanged among the cells tested, and no notable correlation with Cu or Zn contents was observed. On the other hand, all mesothelioma cells highly expressed Mn-SOD compared with MeT-5A, and a very high expression of the enzyme with a robust activity was observed in the two mesothelioma cells (NCI-H226, NCI-H2452) containing a large amount of Mn. CONCLUSIONS: In comparison with MeT-5A human mesothelial cells, some human mesothelioma cells had significantly higher amounts of Mn or Cu and one mesothelioma cell had a significantly higher amount of Zn. Interestingly, all mesothelioma cells overexpressed Mn-SOD compared with MeT-5A, and the cells whose Mn-SOD activity was increased contained higher amounts of Mn. It seemed that intracellular Mn content was positively correlated with Mn-SOD, suggesting that the intracellular Mn level is associated with Mn-SOD activity. These biochemical signatures could be potential disease-related markers of mesothelioma.