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Summary. The double-stranded DNA genome of Blueberry red ringspot virus (BRRV), a member of the family Caulimoviridae, was cloned and sequenced. The genome organization and relationships of the 8303 nt sequence revealed BRRV to be a tentative member of the genus that has been provisionally named “Soybean chlorotic mottle-like viruses”, rather than a member of the genus Caulimovirus, in which it had been placed previously. Insertion of the putative 35S promoter homolog of BRRV into promoterless constructs carrying the UidA (β-glucuronidase) gene resulted in high-level transient expression from cranberry and stable expression from transgenic tobacco. Sequences of 5′-RACE clones derived from transcripts from transgenic tobacco were consistent with the map position of the promoter. [ABSTRACT FROM AUTHOR]

The disposition ofC-dieldrin (HEOD) was examined in a Terrestrial Microcosm Chamber (TMC) model ecosystem consisting of a synthetic soil medium, agricultural crops, numerous invertebrates and a microtine rodent. Residues were determined in air, soil, water, plants, invertebrates, and tissues of the vole ( Microtus canicaudus) and her offspring. Design considerations for this experiment were (a) whether the test system satisfactorily measured the fate of the material applied, (b) whether the results were comparable to field and laboratory studies of the rates and extent of movement, transformation and biological effects of HEOD, and (c) whether the TMC was comparable to other microcosm test systems. The average accountability was 89% of theC-dieldrin applied to three TMCs. At termination, the soil contained 55% (± 19%) of theC, plants 30% (± 18%) and fauna 1.5% (± 0.9%). The vole exhibited an average Ecological Magnification index of 59.5. An average concentration of 17.7 ppm HEOD was noted in the vole brain. Dieldrin adversely affected both vole survival and reproductive performance. The results in the TMC are highly consistent with the behavior of the chemical in the natural environment and in other microcosm systems. [ABSTRACT FROM AUTHOR]

A mathematical model simulating the blood transport and tissue residue distributions of the highly toxic and highly lipid soluble pesticide dieldrin in mammals is presented. This model is a significant improvement over our previously published preliminary model for dieldrin distribution in mammals. The assumptions and working hypotheses of the model are presented and used in generating a set of differential equations based upon mass balance principles. Two simulation cases are examined. The first simply demonstrates the gross features of: 1) Transport limiting conditions; 2) equal transport-equal membrane transfer conditions, and 3) membrane transfer limit conditions. The second studies a single tissue (the blood-brain barrier case) example of the above mentioned conditions. All simulations made were conducted for a hypothetical mature male rate of the average Wistar type eating food ad lib. [ABSTRACT FROM AUTHOR]

The preliminary model of the lipid-phase pharmacokinetics of dieldrin in mammals is applied to evaluation of the probable role of auto-induction, the effect(s) of growth, and the role of compartmentalization. Realistic simulations and comparison to actual data permit the conclusion to be drawn that induction of its own metabolism plays a relatively minor role in the distribution and level of dieldrin residues. Although some of the effects of growth are reasonably well simulated, the model as constructed does not permit compartmentalization. It was concluded that the model should be revised to include aspects of the as-yet quantitatively unknown intracellular binding and membrane transport within the flow-limited model. [ABSTRACT FROM AUTHOR]

A mathematical model for dieldrin (HEOD) distributions in mammalian tissues is presented. The model is based upon lipid-phase transport of dieldrin, large tissue region compartments and destruction of dieldrin via enzymes in the liver. Several simple hypothetical cases involving a 300-gm mature male rat or a 68-kg mature male human are given. Realistic estimates of compartment masses, blood flow, and lipid content are provided, to illustrate the model's predictive potential. Discontinuous dieldrin administration is considered to illustrate procedural effects upon both blood and depot fat lipid-phase dieldrin concentrations. [ABSTRACT FROM AUTHOR]