An overview of the catalytic properties of intermetallic compounds has been made to provide a comprehensive understanding regarding (1) what intermetallic catalysts can do, (2) their fundamental roles in enhanced catalysis, and (3) their advantages over other inorganic materials. A number of chemical transformations using intermetallic catalysts have been surveyed and classified into three major divisionshydrogenation/dehydrogenation, oxidation, and steam reforming and various subsections. The fundamental roles of intermetallic phases obtained from this survey were categorized into four types of effects: (a) electronic, (b) geometric, (c) steric, and (d) ordering effects. The unprecedented steric effects governed by the specific surface structures of intermetallic compounds highlight the unique capabilities of intermetallic materials. On the basis of this overview, we have concluded that intermetallic compounds have the following advantages for fine catalyst design: (i) control of the electronic structure, (ii) a specific and ordered atomic-level structure, and (iii) homogeneity of geometric and electronic structures. Thus, intermetallic compounds are promising inorganic catalyst materials capable of creating a well-designed reaction environment and suitable for developing efficient catalytic systems.

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The rfb gene cluster of Escherichia coli O9 directs the synthesis of the O9-specific polysaccharide which has the structure 32-␣-Man- (132) (18,55), and the O3-and O5-specific polysaccharides of Klebsiella strains are identical to the O8 and O9 polysaccharides of E. coli (8,18,29). Mannans of algal origin were found to exert antitumor activity (37). Such an activity could later be attributed also to the mannan-containing LPS of E. coli and Klebsiella strains (13, 37).The genetics of LPS biosynthesis in enteric bacteria is well documented in recent reviews (33,43,48,55). Two mechanisms, block and monomeric, have been described for O-polysaccharide synthesis (49). In the block mechanism, observed for Salmonella typhimurium and related Salmonella serotypes, the oligosaccharide repeating units are assembled on undecaprenol phosphate (antigen carrier lipid [ACL]) under the direction of rfb genes. The first sugar transferred was found to be galactose-1-phosphate, and the corresponding transferase gene was termed rfbP (48). The repeating units are polymerized under the direction of the rfc gene, which may be located outside of or within the rfb gene cluster (41). The chain length is controlled by the rol gene, located between gnd and his (3, 4). The monomeric mechanism, experimentally proven only for E. coli O8 and O9 (18, 55), consists of the direct and sequential transfer of the monosaccharide residues from their nucleotideactivated precursors to the nonreducing end of the growing polysaccharide chain.The synthesis of some O polysaccharides requires the rfe gene. According to this requirement, LPS biosynthesis can also be divided into rfe-dependent and rfe-independent pathways. The rfe gene, first described by Mäkelä et al. (31), was found to be essential for the synthesis of the O polysaccharide in Salmonella strains of O groups C1 and L, and E. coli O8 and O9 (18, 33) and more recently in E. coli O4, O7, O18, O75, and O111 (1, 23a). It was reported to determine the tunicamycinsensitive transfer of N-acetylglucosamine (GlcNAc)-1-phosphate from UDP-GlcNAc to undecaprenol monophosphate

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Sendai virus (SeV) renders cells unresponsive to interferon (IFN)-K K. To identify viral factors involved in this process, we examined whether recombinant SeVs, which could not express V protein, subsets of C proteins (C, CP P, Y1 and Y2) or any of four C proteins, retained the capability of impeding IFN-K K-mediated responses. Among these viruses, only the 4C knockout virus completely lost the ability to suppress the induction of IFN-K K-stimulated gene products and the subsequent establishment of an anti-viral state. These findings reveal crucial roles of the SeV C proteins in blocking IFN-K K-mediated responses.z 1999 Federation of European Biochemical Societies.