Effects of controlled exposure of L cells to bromodeoxyuridine. II. Turnover rates and activity profiles during cell cycle of bromodeoxyuridine-sensitive and -resistant enzymes.
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Biomedical subjects
Publications and source records attributed to B B Mukherjee.
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Two new penicillins and a new cephalosporin have been synthesized by condensing 2-hydroxy-1-naphthaldehyde with epicillin, 6-aminopenicillanic acid and cephradine, and subsequently reducing the SCHIFF bases with NaBH4. The antimicrobial activities of these compounds are also described.
In the present study the extent of endogenous, type-C virus genome transcription in normal and regenerating mouse liver was analysed by using the technique of nucleic acid hybridization. The RNA preparations from regenerating liver tissues collected at various intervals following partial hepatectomy, and from normal liver samples of BALB/c mice, were hybridized to 3H-DNA complementary to 60 to 70S RNA of an endogenous, N-tropic virus, released spontaneously from BALB/c mouse cells in culture. Although partial transcription of the endogenous virus genome can be clearly detected in normal liver, a significant increase in the level of virus-specific RNA synthesis in the regenerating liver, in comparison to normal liver, is apparent, following partial hepatectomy. This increase in virus-specific RNA synthesis attains its highest level just before the level of DNA synthesis in the regenerating liver reaches its maximum. These observations may indicate a qualitative or quantitative change in the endogenous type-C virus genome transcription pattern in hepatocytes, in response to partial hepatectomy and suggest that this change in the transcription pattern and the initiation of cell proliferation, in regenerating livers, are probably sequential and related events.
Several adult tissues, newborns, and embryos of uninfected BALB/c mice were analysed for RNA complementary to [3H]-DNA transcripts synthesized from an endogenous type-C virus of BALB/c 3T3. The technique of RNA:DNA hybridization was used and the extent of hybridization was measured by the use of a single-strand-specific nuclease (S-I), purified from Aspergillus oryzae. Virus-specific RNA was detected in all adult and embryonic tissues tested. However, the RNA extracted from tissues having higher proliferative activity, such as spleen, small intestine, uterus and embryos, hybridize the [3H]-DNA probe to a greater extent than the RNA from tissues with low proliferative activity, such as kidney and liver. These observations add further support to the view that the repression of the virus genome in normal cells is not complete, and suggest the existence of a correlation between a qualitative or quantitative change in the endogenous C-type virus genome transcription pattern and cell proliferation.
An organism isolated from soil samples collected near a terpene plant grew in the presence of 1-menthene, with no other major source of carbon and energy. The organism was tentatively identified as a member of the genus Cladosporium. When this organism was grown in the presence of 1-menthene, with no other major source of carbon, substantial quantities of beta-isopropyl glutaric acid accumulated in the fermentation medium. beta-Isopropyl glutaric acid is probably an end product of the degradation of 1-menthene by the organism.
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The transformation of three monocyclic terpenes by three soil microorganisms have been studied. The organisms were isolated on, and grew rapidly in, mineral salts medium containing the appropriate terpene substrates as sole carbon sources. These organisms belong to the class Fungi Imperfecti, and two of them have been tentatively identified as Cladosporium species. A Cladosporium species designated T(1) was isolated from terpene-soaked soil, using 1-menthene as the sole source of carbon. The major catabolic product isolated from the growth medium of this organism was found to be a cyclic 1,2-diol identified as trans-p-methane-1,2-diol. A similar but biochemically distinct Cladosporium sp. designated T(7) was isolated on D-limonene. After growth, the medium of this organism contained 1.5 g/liter of the analogous product, trans-limonene-1,2-diol. Minor quantities of the corresponding cis-1,2-diol were also isolated. The third organism, designated as laboratory culture T(8), was isolated on 3-menthene and yielded a diol identified as trans-p-menthane-3,4-diol. From these results it is concluded that the formation of diols is a common intermediate in the fungal metabolism of monocyclic terpenes.
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The present study shows that a high degree of variability in the distribution of XX and XY cells exists among various tissues of artificially assembled or spontaneously occurring mouse chimeras. This variation from the expected equal distribution in various tissues of an animal may have resulted from random distribution, unequal segregation, or selective differences of such cells during development. This variation may also explain the observed intertissue and interanimal variations in the distribution of inactive paternal and maternal X-chromosomes in some mammalian females.
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