Indoor household pesticides: hazardous waste concern or not?

Many indoor household pesticides are efficient and useful tools for a variety of functions necessary to maintain clean, sanitary, and pleasant homes and institutional facilities, and to provide significant public health benefits. They do so by incorporating active ingredients and formulation technology that have not been associated with significant environmental impact in use or when disposed in landfills. Chemical and environmental fate properties, toxicological characteristics, and use patterns of indoor household pesticides that distinguish them from other categories of pesticides which have been associated with environmental contamination should be recognized when HHW policy is debated and established by governmental agencies. Most indoor household pesticides as defined here should not be considered hazardous waste or HHW because those relatively few containers, often no longer full, that have been disposed with MSW over the years have not been associated with environmental contamination. The tiny amounts of those product residues that will reach MSW landfills have been shown, in general, not to have chemical or environmental fate characteristics that would make them susceptible to leaching. Those that do have the potential to leach based on these characteristics, in most cases, do not represent a threat to human health based on toxicological considerations. However, compounds such as propoxur, which are very mobile and relatively persistent in soil and in addition have been associated with significant potential health effects, may be targeted by the screening process as described here and could be selected for further investigation as candidates for special waste management status (such as HHW). Our analysis and recommendations have not been extended to the many types of lawn and garden pesticides that are commonly used by homeowners and are frequently brought to HHW programs. However, their potential for groundwater contamination could also be judged using the same technical considerations as applied in this review to indoor household pesticides. In light of the very high costs of diverting wastes from the MSW stream and into HHW programs, it is recommended that, as a matter of public policy, all categories of household waste that might be considered as HHW be carefully and objectively evaluated for their potential to harm public health or the environment after disposal at MSW landfills.

Purification of eukaryotic RNA polymerase II by immunoaffinity chromatography. Elution of active enzyme with protein stabilizing agents from a polyol-responsive monoclonal antibody.

Active eukaryotic RNA polymerase II (RNAP II) was purified by immunoaffinity chromatography, using a monoclonal antibody (mAb) that reacts with the highly conserved heptapeptide repeat of the largest subunit. This mAb (designated SWG16) was conjugated to CNBr-activated Sepharose and used to purify RNAP II from wheat germ and calf thymus. The subunit composition of the immunoaffinity-purified enzyme was essentially the same as RNAP II purified by conventional chromatography except that it contained only the form with the unproteolyzed largest subunit. Active enzyme could be eluted from the SWG16-Sepharose, at pH 7.9, with combinations of low molecular weight polyols and nonchaotropic salts. The superior eluting procedure used combinations of ethylene glycol (30-40%) and ammonium sulfate (0.5-0.75 M). Active enzyme also could be eluted with a synthetic peptide containing four repeats of the heptapeptide; however, the peptide was not as effective as the polyol and salt combinations for eluting the enzyme. This mAb should be useful for purifying RNAP II from many eukaryotic species. Because the elution of enzyme from the immunoadsorbent seems to be dependent upon the presence of a polyol, this antibody is referred to as a "polyol-responsive mAb." A procedure that helps to identify a polyol-responsive mAb and to optimize the eluting conditions is described. Polyol-responsive mAbs might have broad applicability to the purification of many labile enzymes by immunoaffinity chromatography.

Inhibition of in vivo and in vitro transcription by monoclonal antibodies prepared against wheat germ RNA polymerase II that react with the heptapeptide repeat of eukaryotic RNA polymerase II.

Wheat germ RNA polymerase II was used to raise monoclonal antibodies (mAbs) that cross-react with the largest subunit of calf thymus RNA polymerase II. Most of these mAbs were of the IgM isotype and were shown to react with a synthetic peptide containing the consensus sequence for the C-terminal heptapeptide repeat that has been found on the largest subunit of RNA polymerase II from a variety of eukaryotic organisms. A representative mAb (3WG2) was tested for its effect on transcription in both in vitro and in vivo systems. Antibody 3WG2 did not affect the transcription (elongation) of wheat germ RNA polymerase II on denatured calf thymus DNA. When HeLa cell nuclear extracts were preincubated with the mAb, run-off transcription from a promoter that contains a TATA box (the adenovirus-2 major late promoter) and from a promoter that does not contain a TATA box (the murine dihydrofolate reductase gene promoter = dhfr) was inhibited. Transcription from these promoters was also inhibited by the synthetic peptide containing the consensus sequence when it was conjugated to bovine serum albumin. HeLa cell nuclear extract in which the endogenous RNA polymerase II had been inhibited by the specific mAb was used to examine the ability of added mammalian RNA polymerase II that lacks the C-terminal domain to accurately transcribe specific genes. When calf thymus RNA polymerase II that lacked the C-terminal domain was added back to the inhibited extract, a discrete transcript that was initiated correctly was obtained with the adenovirus-2 major late promoter; however, no discrete transcript was observed from the mouse dhfr gene promoter. When injected into Xenopus laevis oocytes, antibody 3WG2 inhibited transcription of the human histone H2b gene (contains a TATA box) and the human U1 small nuclear RNA gene (does not contain a TATA box), but did not inhibit transcription from RNA polymerase I or RNA polymerase III promoters. These results indicate that the C-terminal heptapeptide repeat plays a critical role in promoter-directed transcription, although enzyme that lacks this domain can initiate from some promoters in vitro.