Estimation of dieldrin in cured tobacco

Estimation of dieldrin in cured tobacco using published methods of clean-up followed by electron-capture g.l.c., suffers from serious interferences. Such interference can be eliminated by Storherr sweep codistillation and t.l.c. on alumina. The limit of detection is 0.01 part/million.     

The effects of dieldrin and isomeric aldrin diols on synaptic transmission in the American cockroach and their relevance to the dieldrin poisoning syndrome

Dieldrin and two of its metabolites, 6,7-trans-dihydroaldrindiol, and 6,7-cis-dihydroaldrindiol, were studied with regard to their toxicity to the American cockroach, effects on ganglia of the ventral nerve cord, and penetration into the ventral nerve cord of poisoned cockroaches. An approximate LD₅₀ for injected doses of dieldrin was 0.45 mg/kg. After injection at 115 mg/kg, the trans isomer of aldrin diol caused about 70%, and the cis isomer about 50% mortality. Injected doses of 40 mg/kg of the three compounds appeared in the ventral nerve cord to the extent of 0.13–0.26% of the doses. Dieldrin was more potent, but slower acting than the diols in causing synaptic after-discharge and elevated spontaneous activity in isolated nerve cords. The results are discussed in relation to other studies on these compounds. It was concluded that, in the American cockroach, dieldrin, rather than either of the diols, is the insecticidal agent in dieldrin poisoning, and that metabolic conversion of dieldrin to the cis and/or trans aldrindiol constitutes a detoxification.     

The concentrations of aldrin and dieldrin and their photoisomers in the atmosphere

Air samples taken in 1973 at a point remote from areas of organochlorine pesticide usage, Bantry Bay in S.W. Ireland, were analysed for aldrin and dieldrin in the vapour state and in association with particupate matter. In addition, some of the samples were analysed for the photoisomers of aldrin and dieldrin, and for pp'-DDT, 1,1-dichloro-2,2-di-(4-chlorophenyl) ethylene (pp'-DDE) and pp'-IDE. Detection and quantitation of all compounds were by gas-liquid chromatography with electron capture detection (g.l.c./e.c.). Confirmatory evidence for the presence of dieldrin and pp'-DDE was obtained with some samplesusing gas-liquid chromatography with mass fragmento-graphic detection (g.l.c./m.f.). Dieldrin was detected in all seventeen samples of air taken, but the mean concentration was 0.36 ng/kg and the range of concentrations was 0.06–1.60 ng/kg. Aldrin was not detected in the samples examined, neither were the two photoisomers. Only pp'-DDE of the pp'-DDT group of compounds was detected in the nine samples examined, and the apparent mean concentration was 0.14 ng/kg. None of the compounds was detected in particulate matter.     

The effects of DDT and dieldrin on rat peritoneal macrophages

The effects of DDT and dieldrin on cell population, viability, and phagocytic activity on the rat peritoneal macrophages were studied. It was observed that both pesticides, at low levels of concentration, exhibited a marked effect on this cell type. At the lowest concentrations tested both pesticides produced an increase in the macrophage population which appeared to be the result of a foreign-body response. At higher concentrations of pesticide this foreign-body response appears to be inhibited. The phagocytic activity of the cells steadily decreased as the concentration of the pesticide administered increased, and a decrease in cell viability with increased pesticide exposure was also noted.     

The toxicity of dieldrin (HEOD) to domestic fowl

Domestic fowl were fed control diet or diets containing 10 or 20 μg/g HEOD. Eggs and samples of blood were collected at intervals and the concentration of HEOD was determined. The concentrations of HEOD in body tissues were also determined after 7 and 13 months. Some of the birds died, but the health of the remainder appeared to be unaffected. The hens of the 20 parts/million group showed an increased egg production, but chick mortality in this group was higher than in the other two groups. The dynamics of HEOD in domestic fowl were qualitatively similar to that in other vertebrates and was consistent with the mamillary type compartmental model.     

Metabolism of [14C]dieldrin in bluegill fish

The exposure of bluegill fish to 50 parts per billion [¹⁴C]dieldrin in a static system resulted in the absorption of 73.00% of the radioactivity in 48 hr. Following transfer of the fish to clean water, only 16.20% of the absorbed radiolabel was eliminated in 23 days. Out of the 93.65% of the absorbed radioactivity recovered, 9 radioactive spots were isolated which included unchanged dieldrin (74.39%), pentachloroketone (8.17%), and aldrin-trans-diol (8.04%) as major metabolites.     

The weathering of ant baits containing aldrin,dieldrin and meirx in trinidad

Sufficinent amounts of insecticide remained in baits to be effecitive against ants over the period when baits retained their attractiveness. Aldrin was lost at similar rates from waterproofed and non-waterproofed baits, but the former had advantages over the latter. Dieldrin and mirex were lost at slower ratesthan aldrin, and insecticide losses were governed by temperature and not by rainfall.     

Conversion of the aldrin/dieldrin metabolite dihydrochlordene dicarboxylic acid-14C in rats

Upon intravenous application of dihydrochlordene dicarboxylic acid-¹⁴C to rats, the radioactivity is quickly excreted, and 44% of the excreted radioactivity consists of metabolites. Nine metabolites have been isolated from feces and urine extracts. Three metabolites could be identified by means of authentic samples by thin layer chromatography, gas chromatography, and mass spectrometry: two isomers of dechlorodihydrochlordene-dicarboxylic acid (metabolites I and II, total 22.5%) and dihydrochlordene-dicarboxylic acid-dimethyl-ester (metabolite III, 11.3%).     

Detection and estimation of Citrus Tristeza Virus infection rates based on Elisa Assays of packing house fruit samples

Enzyme-linked immunosorbent assay (ELISA) proved to be a sensitive detector for citrus tristeza virus (CTV) in orange fruits (Citrus sinensis (L.) Osbeck). Samples of five fruits were taken from 350-kg packing house containers and tested by ELISA to predict the infection rate of CTV in two infected orange groves. The predicted infection rates, 1% and 11%, were in reasonable agreement with the observed rates of 1% (15/1400) and 16% (324/2053), respectively. The 360 test samples from reputedly uninfected groves all tested negative. These results suggest that the ELISA procedure may provide a general method of detecting viral or other systemic pathogenic infections using the fruit as the test material in place of tree tissue. Fruit samples can be collected routinely at the packing house to reduce test costs.     

Bioconversion of dieldrin by wood‐rotting fungi and metabolite detection

BACKGROUND: Dieldrin is one of the most persistent organochlorine pesticides, listed as one of the 12 persistent organic pollutants in the Stockholm Convention. Although microbial degradation is an effective way to remediate environmental pollutants, reports on aerobic microbial degradation of dieldrin are limited. Wood‐rotting fungi can degrade a wide spectrum of recalcitrant organopollutants, and an attempt has been made to select wood‐rotting fungi that can degrade dieldrin, and to identify the metabolite. RESULTS: Thirty‐four isolates of wood‐rotting fungi were investigated for their ability to degrade dieldrin. Strain YK543 degraded 39.1 ± 8.8% of dieldrin during 30 days of incubation. Phylogenetic analysis demonstrated that strain YK543 was closely related to the fungus Phlebia brevispora Nakasone TMIC33929, which has been reported as a fungus that can degrade chlorinated dioxins and polychlorinated biphenyls. 9‐Hydroxydieldrin was detected as a metabolite in the cultures of strain YK543. CONCLUSION: It is important to select the microorganisms that degrade organic pollutants, and to identify the metabolic pathway for the development of bioremediation methods. Strain YK543 was selected as a fungus capable of degrading dieldrin. The metabolic pathway includes 9‐hydroxylation reported in rat's metabolism catalysed by liver microsomal monooxygenase. This is the first report of transformation of dieldrin to 9‐hydroxydieldrin by a microorganism. Copyright © 2010 Society of Chemical Industry     

Uptake of dieldrin,lindane, and DDT by isolated rat hepatocytes

Studies of the uptake of dieldrin, lindane, and DDT by isolated rat hepatocytes in Krebs-Henseleit salt solution containing 2.34% bovine serum albumin have shown that the partition equilibrium of these hydrophobic organochlorine compounds is established very rapidly between the hepatocytes and the extracellular medium by reversible uptake and release processes. In the hepatocyte suspension system, these compounds are in dynamic partition equilibrium between the hepatocytes and the Krebs-Henseleit salt solution, and also between the bovine serum albumin molecules and the solution. The respective rate constants for the uptake and release processes were 0.83 and 2.52 × 10^?2 sec^?1 in a 2-ml suspension containing 10⁶ cells. It has thus been demonstrated that the transport of hydrophobic organochlorine compounds between the hepatocytes and the extracellular medium is a much faster process than the metabolic transformation reaction in hepatocytes.     

Synthesis and confirmation of structure of four mammalian metabolites of dieldrin and endrin

The first syntheses of syn-12-hydroxydieldrin, syn-12-hydroxyendrin and anti-12-hydroxyendrin have been accomplished by debenzoylation and epoxidation of three isomeric adduction products of hexachlorocyclopentadiene and 1,7,7-trinorborna-2,5-dien-7-yl benzoate. A third known metabolite of endrin, 12-ketoendrin, and a putative metabolite of dieldrin, 12-ketodieldrin, were prepared from the corresponding alcohols by oxidation with chromium trioxide. Characterisation of the three debenzoylated intermediates as syn-12-hydroxyaldrin, and syn- and anti-12-hydroxyisodrin constitutes the first syntheses of these three possible metabolites of aldrin and isodrin.     

Cytochrome P-450 content and aldrin epoxidation to dieldrin in isolated rat hepatocytes

A rat hepatocyte suspension effectively epoxidized aldrin to dieldrin with a V_max of 7.19 mol/mol P-450/min and a K_m of 9.27 μM. Viability and metabolic activity were stable for 6 hr after isolation when cells were maintained at room temperature (20°C) with the gentle introduction of $\text{O}{}_2\text{CO}{}_2$ onto the surface of the suspension. The cytochrome P-450 content of the suspension was 303 pmol/10⁶ cells. Primary maintenance culture of the cells also epoxidized aldrin. During culture for 3 days, metabolic activity decreased slowly day by day. Metabolic activity of microsomal fraction from rat liver was also examined. Microsomes epoxidized aldrin with a V_max of 5.11 mol/mol P-450/min and a K_m of 1.64 μM. Significant loss of some subspecies of cytochrome P-450 during fractionation of liver homogenate was indicated.     

Electrophysiological studies on the effect of sesamex upon the action of dieldrin in Blaberus discoidalis

Treatment of the metathoracic ganglion of the cockroach, Blaberus discoidalis, with dieldrin (HEOD) at a concentration of 10^?5M produced changes in spontaneous efferent activity and afterdischarge in efferent pathways. Pretreatment with sesamex markedly reduced the spontaneous activity caused by dieldrin and also reduced the latency of appearance of symptoms from 60 min to nearly 30 min. However, pretreatment with sesamex did not alter the intensity and duration of the dieldrin-induced synaptic afterdischarge. Pretreatment of cockroaches with sesamex did not measurably change the toxicity of dieldrin in vivo.     

Immunotoxicity of aminocarb : I. Comparative studies of sublethal exposure to aminocarb and dieldrin in mice

Immunotoxicity of a carbamate pesticide, aminocarb (Matacil), introduced orally in sublethal doses to C57B1/6 inbred mice, has been compared to the immunosupressive effects of the organochlorine pesticide, dieldrin (served as a positive control), in bacterial and viral infections. In vivo infection of pesticide-exposed mice with Salmonella typhimurium and mouse hepatitis virus 3 (MHV3) showed that two subsequent LD₅₀ doses of aminocarb did not decrease the resistance of animals to the pathogens, whereas exposure to dieldrin resulted in augmented mortality. In vitro studies showed that the spread of MHV3 virus infection and virus-induced cytopathic effects (cpe) were augmented in peritoneal macrophages after exposure to aminocarb, albeit to a much less extent than in the dieldrin group. Similarly, a decrease in the anti-MHV3 IgM serum antibody titer by aminocarb was less marked than in the dieldrin group. Alternatively, immunization of animals with a neutral antigen, sheep red blood cells (SRBC), showed a significant increase in the anti-SRBC humoral response 10 days after a single oral exposure to LD₅₀ aminocarb. The cellular immune response, determined by mixed lymphocyte reaction, was unaffected by sublethal aminocarb exposure. In addition, macrophage antigen processing of a single protein, avidin, was unaffected by aminocarb, contrary to the inhibition of avidin processing in macrophages from dieldrin-gavaged mice. The data do not indicate that immunotoxic properties are associated with aminocarb, and only slight effects with high sublethal doses of orally given aminocarb on macrophage susceptibility to the MHV3 viral pathogen were observed at a terminal phase of the disease.     

Excitation of central neurons by dieldrin and picrotoxinin in susceptible and resistant Drosophila melanogaster (meigen)

Neurophysiological studies were used to characterize the resistance mechanism in a new cyclodiene-resistant strain of Drosophila melanogaster. Suction electrode recordings were taken from the peripheral nerves of transected larval central nervous system. Treatment of nerve preparations with 1 mM GABA reduced the spontaneous firing of peripheral nerves. This inhibition was effectively reversed within 10 min by exposing preparations from susceptible insects (Oregon-R wild type) to 10 μM dieldrin. In contrast, 30 min incubations with 10 μM dieldrin had no effect on preparations from resistant individuals. At 10 μM, picrotoxinin was also effective in antagonizing the action of GABA in susceptible nerve preparations. In recordings from resistant insects (n = 3), picrotoxinin displayed either no antagonism of GABA-dependent inhibition, weak antagonism of GABA, or hyperexcitation indistinguishable from those of susceptible preparations. These results demonstrate that cyclodiene resistance in the Maryland strain of D. melanogaster is present at the level of the nerve, and that the resistance extends to picrotoxinin, albeit at a reduced level. The possible role of an altered GABA receptor in this resistance is discussed.