Semiconductive Nature of Lead-Based Metal-Organic Frameworks with Three-Dimensionally Extended Sulfur Secondary Building Units.

Recently, metal-organic frameworks (MOFs) composed of sulfur secondary building units (sulfur-SBUs) have attracted significant attention as unique electronic materials with high conductivities and photo- and electrocatalytic properties. Herein we report the crystal structure of KGF-1, an example of a Pb-MOF composed of three-dimensionally extended sulfur-SBUs that displays molecular sieving behavior, visible-light absorption, and a semiconductor band structure and is a hydrogen-evolution photocatalyst.

Production of monoclonal antibodies directed to Hanganutziu-Deicher active gangliosides, N-glycolylneuraminic acid-containing gangliosides.

We have established three kinds of monoclonal antibodies against gangliosides containing N-glycolylneuraminic acid (NeuGc) by immunization of BALB/c mice with the purified gangliosides inserted into liposomes comprising Salmonella minnesota R595 lipopolysaccharides, and fusion of spleen cells with a mouse myeloma cell line. One monoclonal antibody, SHS-1, which was generated by immunizing mice with purified i-active ganglioside(NeuGc), reacted specifically with the i-active ganglioside(NeuGc) used as an immunogen. Structurally related gangliosides, such as GM3(NeuGc), sialosylparagloboside (SPG) (NeuGc), or I-active ganglioside(NeuGc), corresponding gangliosides [GM3 containing N-acetylneuraminic acid (NeuAc), SPG(NeuAc), i-active ganglioside(NeuAc), and I-active ganglioside(NeuAc)], other gangliosides, or neutral glycosphingolipid (GSL) were not recognized by the monoclonal antibody. These findings indicate that the SHS-1 monoclonal antibody may be specific for NeuGc-containing i-active ganglioside. On the other hand, the other two monoclonal antibodies, MSG-1 and SPS-20, which were generated by immunizing mice with purified ganglioside GM3(NeuGc) and SPG(NeuGc), respectively, showed cross-reactivity to structurally related gangliosides. The MSG-1 monoclonal antibody exhibited reactivity to ganglioside GM3(NeuAc). The SPS-20 monoclonal antibody also cross-reacted with SPG(NeuAc), i-active ganglioside(NeuGc), and i-active ganglioside(NeuAc). Neither MSG-1 nor SPS-20 reacted with corresponding gangliosides, other gangliosides, or neutral GSLs tested. Using the SHS-1 antibody specific for i-active ganglioside(NeuGc), we studied the expression of NeuGc-containing antigen in human colon cancer tissue. An NeuGc-containing glycoconjugate was detected in the colon cancer tissue.

Establishment of monoclonal antibodies specific for ganglioside GM1: detection of ganglioside GM1 in small cell lung carcinoma cell lines and tissues.

Three kinds of anti-GM1 monoclonal antibodies, AGM-1, -2, and -3, of the IgM class were produced by the immunization of BALB/c mice with ganglioside GM1 inserted into liposomes with Salmonella minnesota R595 lipopolysaccharides and fusion of the spleen cells with a mouse myeloma cell line. The specificities of the monoclonal antibodies obtained were elucidated through complement-dependent liposome immune lysis assay and enzyme immunostaining on thin-layer chromatograms. All of the monoclonal antibodies reacted only with ganglioside GM1, and structurally related glycosphingolipids, such as fucosyl-GM1, asialo-GM1, GM2, and GD1b, and the other gangliosides (GM3 and GD1a) tested showed no reactivity to the 3 monoclonal antibodies. These findings suggest that the monoclonal antibodies obtained may be specific for ganglioside GM1. These anti-GM1 monoclonal antibodies were used to define the expression of ganglioside GM1 on small cell lung carcinoma (SCLC) cell lines and tissues. In flow cytometric analysis and immunostaining studies, we observed that ganglioside GM1 was highly expressed on the SCLC cell lines. Results obtained with flow cytometry and immunohistochemistry agreed well with the immunochemical determination of ganglioside GM1 in lipid extracts of cell lines. Furthermore, expression of ganglioside GM1 in tumor tissues from patients with SCLC was ascertained by the immunohistochemical examination of acetone-fixed paraffin-embedded tissue sections. Ganglioside GM1 was detected in 5 of 19 SCLC tissues. These results suggest that ganglioside GM1 is expressed in SCLC cells.