Human membrane cofactor protein (MCP, CD46) has been suggested, although no convincing evidence has been proposed, to be a fertilization-associated protein, in addition to its primary functions as a complement regulator and a measles virus receptor. We have cloned a cDNA encoding the murine homologue of MCP. This cDNA showed 45% identity in deduced protein sequence and 62% identity in nucleotide sequence with human MCP. Its ectodomains were four short consensus repeats and a serine/threonine-rich domain, and it appeared to be a type 1 membrane protein with a 23-amino acid transmembrane domain and a short cytoplasmic tail. The protein expressed on Chinese hamster ovary cell transfectants was 47 kDa on SDS/PAGE immunoblotting, approximately 6 kDa larger than the murine testis MCP. It served as a cofactor for factor I-mediated inactivation of the complement protein C3b in a homologous system and, to a lesser extent, in a human system. Strikingly, the major message of murine MCP was 1.5 kb and was expressed predominantly in the testis. It was not detected in mice defective in spermatogenesis or with immature germ cells (until 23 days old). Thus, murine MCP may be a sperm-dominant protein the message of which is expressed selectively in spermatids during germ-cell differentiation.

We have studied the fluorescence dynamics of “nonfluorescent” flavoproteins including flavodoxin (FD), its mutants W60F, Y98F, and W60F/Y98F, and riboflavin binding protein (RBP) with the femtosecond fluorescence up-conversion method and have observed the fluorescence quenching dynamics of FD and its mutants for the first time. The strong fluorescence quenching in these flavoproteins seems to be caused by ultrafast electron transfer (ET) from aromatic amino acid residues to the excited flavin chromophore in stacked configuration according to previous transient absorption studies. In the present work, we have made comparative studies on the dynamics of fluorescence quenching due to ET to the excited chromophore in RBP and FD. We have observed also fluorescence dynamics of FD mutants where active electron donors Trp·NH and Tyr·OH are partially (either of them) or completely replaced by inactive phenylalanine and directly demonstrated the ET mechanism of the ultrafast fluorescence quenching in PNS of FD.

The development of a new catalyst effective for the vapor-phase Beckmann rearrangement of cyclohexanone oxime has made it possible to establish a commercial process for the production of "-caprolactam without producing any ammonium sulfate. Through fundamental studies of the catalyst, it was discovered that an MFI-type zeolite composed exclusively of silica had a high selectivity and activity for the vapor-phase Beckmann rearrangement. Based on acidity measurements and on the reactivity of oximes with different sizes as well as the calculation results of the deprotonation energies of some silanols, we have suggested that the active sites are nest silanols located close to their mouth of the micro pores. By addition of methanol into the reaction system, the selectivity for "-caprolactam was markedly improved to the levels required for industrialization. A fluidized bed reactor was used for the reaction system in order to maintain a continuous production. By combining the ammoximation process for production of cyclohexanone oxime using the TS-1 catalyst and the vapor-phase Beckmann rearrangement, a commercial plant has been operating on a 60000 tons per year scale since April 2003, without any troubles.

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The SN2 reaction has been well recognized not to occur at sp2 carbons, while such an SN2‐type substitution reaction was found to proceed readily at the sp2 nitrogen of oximes. Ab initio MP2 calculations show that the activation energy of the nucleophilic substitution at sp2 nitrogen is almost same as that of the Beckmann rearrangement. By the intramolecular SN2‐type reaction at the oxime nitrogen, various aza‐arenes and cyclic imines, such as quinolines, aza‐spiro compounds, and dihydropyrroles, can be synthesized. Intermolecular substitution of oximes with organometallic reagents also proceeds, and electrophilic amination of Grignard reagents is accomplished by the use of 4,4,5,5‐tetramethyl‐1,3‐dioxolan‐2‐one O‐(phenylsulfonyl)oxime. Anion radicals generated by one‐electron reduction of oxime derivatives act as iminyl radical equivalents. That is, the intramolecular C–N bond formation of γ,δ‐unsaturated or β‐aryl oximes is induced by a single electron transfer to give various pyrroles, quinolines, and carbolines, in which phenols, hydroquinones, or copper reagents can be used as electron donors. A photo‐induced radical process is also applied to the transformation of γ,δ‐unsaturated oximes to dihydropyrroles. Oxidative addition of oximes to palladium(0) complexes generates alkylideneaminopalladium(II) species, which are utilized as key intermediates in carbon–nitrogen bond formation. Various aza‐heterocycles, including pyrroles, pyridines, isoquinolines, spiroimines, and aza‐azulenes, are synthesized from O‐(pentafluorobenzoyl)oximes having olefinic moieties via the intramolecular Heck‐type reaction (amino‐Heck reaction) by treatment with a catalytic amount of a Pd0 complex. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Background: The largest cytogenetic survey involving infertile men was undertaken to clarify whether chromosomal abnormalities, including autosomal abnormalities, affect semen qualities. Method: All male patients who visited an infertility clinic from 1990 to 1998 underwent chromosomal and semen analysis. Results: Chromosomal abnormalities were found in 225 of 1790 patients (12.6%). The most frequent anomaly was Klinefelter syndrome (64 cases). Autosomal anomalies accounted for 126 cases. 46,XY,1qh(+) was the most common autosomal anomaly (30 cases) and its incidence was significantly higher than those of normal controls. The seminograms of these patients varied widely, with nine patients having azoospermia and three patients achieving natural pregnancies. Itis not yet clear if this karyotype affects spermatogenesis. Conclusion: Autosomal anomalies as well as sex chromosomal abnormalities might affect spermatogenesis. Cytogenetic study is important before intracytoplasmic sperm injection.

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