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     

Bioaccumulation of endosulfan (Thiodan insecticide) in the tissues of Louisiana crayfish, Procambarus clarkii

The bioaccumulation potential of endosulfan was determined by constantly exposing male and female adult crayfish, Procambarus clarkii to 100 ppb Thiodan insecticide for 8 wks. The crayfish were removed at 2 wk intervals and the uptake by tissues (whole-body) was determined by electron capture gas-chromatography. The same number of pre-exposed crayfish (100 ppb Thiodan) were transferred to endosulfan-free water after 8 wks, and insecticide loss (depuration) was similarly quantitated. The maximum amount of insecticide and its metabolites detected after 8 wks were 197 ppb endosulfan II, 18 ppb endosulfan I and 3 ppb endosulfan sulfate. During the first 4 wks of depuration, endosulfan loss from cryfish tissues occurred rapidly, and only 3 ppb endosulfan I remained. No endosulfan II and sulfate were detected beyond 4 wks. The residues in male vs female were not significant statistically. Bioaccumulation factor (BF) for endosulfan II for crayfish tissues was 1.97, which is considerably lower than for other aquatic invertebrates (26 for scallop, Chlamys opercularis and 600 for mussel, Mytilus edulis. The presence of endosulfan sulfate in the tissues cannot be considered as 'detoxification' which is as toxic as the parent compound.     

Conservation Genetics of the Black Rhinoceros (Diceros bicornis), I: Evidence from the Mitochondrial DNA of Three Populations

Abstract: A drastic decline in the number of black rhinoceroses ( Diceros bicornis ), primarily as a result of poaching places this species in imminent danger of extinction. The remaining black rhinos are divided into small, isolated populations that are vulnerable to demographic extinction, disease epidemics, genetic drift and inbreeding. Some conservationists have suggested minimizing these threats by moving as many animals as possible from different isolated populations to a few safe "rhino sanctuaries." To examine the possible long-term genetic consequences of such a strategy, we focused our efforts on determining the level of genetic differences among the remaining black rhino populations by examining restriction fragment length polymorphisms of the rapidly evolving mitochondrial DNA molecule. The 23 black rhinos in our survey, including animals from three geographic regions and two named subspecies, showed very little mitochondrial DNA differentiation. Only 4 out of 18 restriction enzymes revealed any mtDNA polymorphism, and the average estimated percent sequence divergence between the four mtDNA genotypes observed as 0.17%. Mitochondrial DNA divergence between the two named subspecies, D. b. minor and D. b. michaeli , was estimated to be only 0.29%. These results indicate a very close genetic relationship among the black rhinos in our survey. Thus, the mitochondrial DNA data suggest that within national boundaries, the black rhino populations we sampled may be considered single populations for breeding purposes, which might increase the species' probability of survival.     

Job involvement as a moderator variable in the life events stress–illness relationship

It is hypothesized that the relationship between life events and reported symptoms of psychological and physical illness is moderated by the extent to which a person is job-involved. Analysis of the data in a sample of employed men shows large correlations between a measure of life events and reported symptoms for men with low job involvement, substantially higher than where the men are highly job-involved.