Biopharmaceutical studies of spirobishexahydropyrimidine.

Oral administration of spirobishexahydropyrimidine showed an increase in the activity of serum transaminases, lactate dehydrogenase and alkaline phosphatase. Biological half life and other pharmacokinetic parameters showed rapid absorption and slow elimination of the drug.     

Southeast Asian Mitochondrial DNA Analysis Reveals Genetic Continuity of Ancient Mongoloid Migrations

Human mitochondrial DNAs (mtDNAs) from 153 independent samples encompassing seven Asian populations were surveyed for sequence variation using the polymerase chain reaction (PCR), restriction endonuclease analysis and oligonucleotide hybridization. All Asian populations were found to share two ancient AluI/DdeI polymorphisms at nps 10394 and 10397 and to be genetically similar indicating that they share a common ancestry. The greatest mtDNA diversity and the highest frequency of mtDNAs with HpaI/HincII morph 1 were observed in the Vietnamese suggesting a Southern Mongoloid origin of Asians. Remnants of the founding populations of Papua New Guinea (PNG) were found in Malaysia, and a marked frequency cline for the COII/tRNA(Lys) intergenic deletion was observed along coastal Asia. Phylogenetic analysis indicates that both insertion and deletion mutations in the COII/tRNA(Lys) region have occurred more than once.     

Mutagenic activity of oxathiolane steroids: structural requirement for the genotoxic activity in Salmonella and E. coli.

Oxathiolanes and disulfonyl derivatives of steroids were tested for mutagenic activity in the Ames tester strains. The test compounds exhibited mutagenic activity without metabolic activation although metabolic activation markedly enhanced their activity. A significant decrease in the survival of the radiation-sensitive mutants recA, lexA and rer of E. coli was observed as compared to their wild-type counterpart in the presence of the test steroid. Structural features which appear to be crucial for the mutagenic activity in these steroidal drugs are: (i) an electron-donating group at position 3, and (ii) a bulky group anchored at the 5th and 6th positions. The test steroids appear to damage DNA which in turn initiates the SOS repair with the concomitant induction of mutation.     

Immobilization of Rhodococcus equi DSM 89-133 onto porous celite beads for cholesterol side-chain cleavage

Summary Rhodococcus equi cells immobilized onto porous celite beads were active in side-chain cleavage of cholesterol. The effect of bead size, adsorption time and washing cycles were examined. The degradation of cholesterol side-chain using adsorbed cells was studied in batch and semi-continuous systems. Compared to free cells (80 mol%), the end-product (1,4-androstadiene-3,17-dione and 4-androstene-3,17-dione) profile was lower (70 mol%) with the celite-adsorbed system. Correspondence to: B. N. Johri     

Nucleotide sequences of three different isoforms of beta-tubulin cDNA from Chinese hamster ovary cells.

The complete cDNA sequences of two clones encoding beta-tubulin isotypes and the partial sequence of a third isoform from Chinese hamster ovary cells have been determined. The deduced amino acid sequences of the three isoforms show extensive homology to each other as well as with other alpha and beta-tubulin sequences from various species. These results provide evidence for the expression of three different isoforms of beta-tubulin in Chinese hamster ovary cells.     

Mammalian pyruvate carboxylase: effect of biotin on the synthesis and translocation of apo-enzyme into 3T3-L adipocyte mitochondria

The effect of biotin on the induction (and possible requirement for uptake into mitochondria) of apopyruvate carboxylase has been examined in 3T3-L adipocytes. Cells fed biotin-sufficient medium contained only holoenzyme in mitochondria and no apoenzyme was detected. The amount of apoenzyme elaborated in biotin-deficient 3T3-L adipocytes was comparable to the holopyruvate carboxylase protein found in cells maintained on biotin-sufficient medium. Like the holoenzyme, the apoenzyme was detected exclusively in the mitochondrial fraction of 3T3-L adipocytes. This indicates that the synthesis of apopyruvate carboxylase and its translocation into mitochondria occur independently of the cofactor, biotin.     

Microbial transformation of sterols to C19-steroids by Rhodococcus equi

A wild-type strain of Rhodococcus equi, isolated from soil, degraded cholesterol, -sitosterol, stigmasterol and mixed sterois to androst-4-ene-3,17-dione (AD) and androsta-1,4-diene-3,17-dione (ADD). A definite preference for a relatively simply structured cholesterol side chain was observed. Highest specific cholesterol side-chain cleavage was associated with active growth of the culture. Maximum yield of ADD was obtained when sodium acetate and cholesterol were incorporated together in the medium. Specific side-chain cleavage required the presence of 2,2-dipyridyl, an inhibitor of ring cleavage.S. Ahmad and B.N. Johri are with the Department of Microbiology, College of Basic Sciences and Humanities, G.B. Pant University of Agriculture and Technology, Pantriagar 263 145, Nainital, UP, India. P.K. Roy, A.W. Khan and S.K. Basu are at Fermentation Technology Division, Central Drug Research Institute, Lucknow, India.     

Reversed-phase chromatographic method for specific determination of glutathione in cultured malignant cells

A chromatographic method for the specific determination of glutathione in malignant cell lines is described. The method is based on the ability of glutathione-S-transferase to specifically and quantitatively conjugate glutathione to 1-chloro-2,4-dinitrobenzene and chromatographic quantitation of the resultant conjugate, dinitrophenyl-S-glutathione, by reversed-phase liquid chromatography. The assay can be performed on 20 000 g supernatants of cell homogenates without acid extraction. 2-Mercaptoethanol, a sulfhydryl compound often used as a thiol-protective agent to preserve enzymatic activities of a number of enzymes, did not interfere with glutathione determination by this method. The dinitrophenyl-S-glutathione isolated from either standard glutathione samples or from cell homogenates was shown to be identical to authentic dinitrophenyl-S-glutathione using mass spectrometry. Recovery of glutathione in standard samples by the current method was identical to that determined using 5,5′-dithiobis(2-nitrobenzoic acid). Exogenous glutathione added to supernatants of cell homogenate in the presence or absence of 2-mercaptoethanol was also completely recovered.     

Synergistic interaction between immune serum and thoracic duct cells in the adoptive transfer of rapid expulsion of Trichinella spiralis in adult rats

Rapid expulsion of Trichinella spiralis could be transferred to naive adult rats with thoracic duct lymphocytes and immune serum. Thoracic duct cells collected from Days 3-5 and immune serum collected on Day 28, respectively, after infection were effective. Both cells and serum were unable to transfer rapid expulsion when given alone, even in large volumes. Recipients of immune serum and cells eliminated a significantly higher number of larvae than control rats by 1 hr after challenge with muscle larvae. Rapid expulsion produced 30-80% larval worm rejection but could not be increased by the transfer of more cells or immune serum. Mucus trappings did not appear to play a role in the rejection process. After transfer of 2 x 10(8) cells and 4.0 ml immune serum, rapid expulsion persisted for less than 1 week. However, after adoptive transfer of cells alone, the gut remained functionally receptive to the passive transfer of immune serum for 7 weeks. Therefore, the changes effected by transfer of cells were long lived in contrast to the 1 week, or less, of functional persistence by transferred immune serum. The data indicate that two separate processes, one cell mediated and the other immune serum mediated, interact synergistically in the intestine and lead to the expression of rapid expulsion.     

Biopharmaceutical studies of 3-substituted isatin derivatives

The metabolic fate of isatin hydrazone (Ia), isatin-3-thiosemicarbazone (Ib), isatin-3-semicarbazone (Ic), isatin-3-phenylhydrazone (Id), isatin oxime (Ie) and 3-hydroxy-3-acetonyl oxindole (II) was studied in rabbits. The compounds were administered orally in the dose of 300 mg/kg body wt. Isatin anthranilic acid, tryptophan and nicotinic acid were identified as the major metabolites excreted in urine. The 3-hydroxy-3-acetonyl oxindole (II) gave on additional metabolite, oxindole. The major metabolites were separated and identified unambiguously on thin layer silica gel plate. Metabolic pathways have been proposed to explain the biotransformation of the compounds investigated.