The in vitro metabolism of lindane by an enzyme preparation from chicken liver.

The soluble fraction (105,000 x g, 30 min) of chicken liver homogenates contained an enzyme(s), probably a dehydrochlorinase(s), which metabolized lindane in vitro. The reaction was glutathione dependent and took place anaerobically. The enzyme(s) also metabolized the alpha- and delta-isomers but not the beta-isomer. About 66% of the in vitro metabolites were soluble in petroleum ether. From the ether-soluble fraction, o-, p- amd m-dichlorobenzene, 1,2,3- and 1,2,4-trichlorobenzene, gamma-2,3,4,5,6-pentachlorocyclohex-1-ene (gamma-PCCH), 2,3- and 2,4-dichlorophenol and 2,4,6-trichlorophenol were identified by comparison of mass spectra and gas chromatographic data with those of reference compounds. Seven additional metabolites were tentatively identified from their mass spectra data. These metabolites were: chlorobenzene, 2 isomers of trichlorocyclohexene, dichlorocyclohexadienetriol, chlorophenol, trichlorocyclohexenol and trichlorocyclohexanediol. The petroleum ether-extracted aqueous phase contained a number of unidentified conjugated metabolites. It was concluded that the metabolic pathway for lindane in the chicken is quite similar to that in the pheasant.     

Anaerobic microbial dechlorination: an approach to on-site treatment of toxaphene-contaminated soil

Enhanced microbial degradation of toxaphene by natural microorganisms occurred in soil and sediment amended with organic matter kept under anaerobic (flooded) conditions. Laboratory experiments yielded a dissipation half-life of approximately 3 and 1 week for soil and sediment, respectively, containing 10 ppm of technical toxaphene and a 1% alfalfa meal amendment. Dissipation was accompanied by an increase in early eluting gas chromatographic peaks and a decrease in later eluting peaks, indicating that dechlorination had occurred. Enhanced anaerobic dissipation also took place in soil containing 500 ppm of toxaphene, although at a lesser rate than at 10 ppm, and when cotton gin waste was used as amendment in place of alfalfa meal. Sediment in a toxaphene-contaminated pesticide waste disposal ditch was amended with 10% steer manure and flooded to ascertain field utility of the technique for on-site decontamination. Toxaphene residues were reduced from 63 to 23 ppm in 120 days, and some degradation activity still occurred up to 8 months after this single treatment.     

Genetic Polymorphisms and Their Relationships with Inbreeding and Breed Structure in Rare British Sheep: The Portland, Manx Loghtan, and Hebridean

Abstract: 320 sheep of three rare British breeds were typed for blood group and biochemical polymorphism. Genetic distance was least between the Manx Loghtan and Hebridean (D = 0.1241, supporting historical evidence of a close relationship between the breeds. Distances to the Portland breed were 0.144 and 0.186, respectively. The claim that the Portland is related to the Dorset Horn was substantiated by the fact that both breeds possess the i blood group allele. Pedigree analysis showed that most rare or unusual alleles in the three bee could be traced to particular ancestors, which had been accepted for registration as foundation stocks, i. e., there was little evidence of genetic introgression from other breeh. Highly inbred sheep showed the predicted lack of heterozygosity.
When these sheep were first registered (1973), foundation stocks were defined comprising animals of correct breed type. Today, the pedigree of each sheep reveals the percentages of its ancestry attributable to each foundation stock Sheep were classified according to these percentages into subgroups, each of which, therefore corresponds to a strain within the breed Genetic distances were calculated among these subgroups within each breed For the Portland these distances were rather large (D up to 0.069), but distances were rather small for the other two breeds (D up to 0.027). The Manx Loghtan and Hebridean breeds are therefore relatively homogeneous while the genetic distances among Portland subgroups reveal the genetic consequences of the reproductive isolation of certain important flocks