We report the analysis of the distribution of the C677T mutation on the methylenetetrahydrofolate reductase (MTHFR) gene in prenatally diagnosed neural tube defects (NTD) cases and controls. In contrast to previous reports, we found the same distribution in fetuses with NTD and controls, which suggests that the MTHFR C677T mutation cannot be regarded as a genetic risk factor for NTD.

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DNA-DNA hybridization was used to determine the levels of genomic relatedness of the three species of "false neisseriae," Neisseria caviae, Neisseria cuniculi, and Neisseria ovis. The reference strains of these species exhibited high levels of intraspecies relatedness (93 to 100% for N. caviae, 79 to 100% for N. cuniculi, and 68 to 100% for N. ovis) but low levels of interspecific relatedness (less than 34%) to each other and to various species belonging to the Q subclass of the Proteobacteria (Kingella kingae, Neisseria gonorrhoeae, Neisseria meningiiidis, and Oligellu urethralis) or to the y subclass (Branhamella catarrhalis, Kingella indologenes, Moraxella atluntae, Moraxella bovis, Moraxella lucunata subsp. lacunata, Moraxella lucunata subsp. liquefaciens, Moraxella nonliquefaciens, Moraxella osloensis, and Moraxella phenylpyruvica) . However, the levels of DNA-DNA hybridization for the three species of "false neisseriae" were significantly higher with the species belonging to the y subclass (average, 13.7%) than with the species belonging to the B subclass (average, 4.5%).These data suggest that N. caviae, N. cuniculi, and N. ovis are three separate genomic species in the y subclass.An ascendant hierarchical classification based only on fatty acid profiles distinguished four main classes containing (i) most of the 6cclassical moraxellae," the "false neisseriae," and B. catarrhalis, (ii) only Acinetobacter spp., (iii) M. nonliquefaciens and "misnamed moraxellae" (M. atluntae, M. osloensis, and M. phenylpyruvica), and (iv) the '&true neisseriae," the three Kingella species, and 0. urethralis. Fatty acids that distinguish these four classes were identified. The fatty acid profiles of the two strains of Psychrobacter immobilis which we studied are not very similar to the profiles of the other taxa. Our results support the hypothesis that the three species of "false neisseriae," B. catarrhalis, the "classical moraxellae," and Acinetobacter spp. should be included in the same family.The genus Branhamella, containing Branhamella catarrhtzlis as the only species, was proposed by Catlin in 1970 to accomodate Nekseria catarrhalis, which was more closely irelated to Moraxella spp. than to Neisseria spp. as determined by genetic transformations (12). In 1979, Bmre proposed that B. catarrhalis should be included in the genus Moraxella and that this genus should be divided into two subgenera, subgenus Moraxella for rod-shaped bacteria and subgenus Branhamella for coccal organisms, including Moraxella (Branhamella) catarrhalis (4). In 1984 Bovre recognized the following four genera in the family Neisseriaceae: Neisseria, Moraxella (with two subgenera), Acinetobacter, and Kingella (5).The genus Neisseria, as described by Vedros (47), contains 11 species that are regarded in this paper as the "true neisseriae" and the following 4 species regarded as species incertae sedis: Neisseria caviae, Neisseria ovis, and Neis-,yeria cuniculi (the "false neisseriae"), as well as Neisseria