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PubMed2002

Specific and overlapping functions of the nuclear hormone receptors CAR and PXR in xenobiotic response.

The products of the cytochrome P450 (CYP) genes play an important role in the detoxification of xenobiotics and environmental contaminants, and many foreign chemicals or xenobiotics can induce their expression. We have previously shown that the nuclear hormone receptor CAR (Constitutive Androstane Receptor, NR113) mediates the well studied induction of CYP2B10 gene expression by phenobarbital (PB) and 1, 4-bis-[2-(3, 5,-dichloropyridyloxy)] benzene (TCPOBOP). We have used the CAR knockout mouse model to explore the broader functions of this xenobiotic receptor. In addition to the liver, CAR is expressed in the epithelial cells of the villi in the small intestine, and this expression is required for CYP2B10 induction in response to PB and TCPOBOP in those cells. In agreement with previous observations that CAR can bind to regulatory elements in CYP3A genes, CAR is also required for induction of expression of CYP3A11 in response to both PB and TCPOBOP in liver. In males, CAR is also required for induction of liver CYP2A4 expression. In wild type animals, pretreatment with the CAR inverse agonist androstenol blocks the response of both the CYP2B10 and CYP3A11 genes to PB and TCPOBOP, and decreases basal CYP3A11 expression. CAR is also required for the response of CYP2B10 to several additional xenobiotic inducers, including chlorpromazine, clotrimazole and dieldrin, but not dexamethasone, an agonist for both the xenobiotic receptor PXR (Pregnane X Receptor NR112) and the glucocorticoid receptor. Chlorpromazine induction of CYP3A11 is also absent in CAR-deficient animals, but the responses to clotrimazole and dieldrin are retained, indicating that both of these inducers can also activate PXR (Pregnane X Receptor NR112). We conclude that CAR has broad functions in xenobiotic responses. Some are specific to CAR but others, including induction of the important drug metabolizing enzyme CYP3A, overlap with those of PXR.

Animals↗
PubMed2006

Comprehensive re-analysis of archived herring gull eggs reconstructs historical temporal trends in chlorinated hydrocarbon contamination in Lake Ontario and Green Bay, Lake Michigan, 1971-1982.

Herring gull egg homogenates collected between 1971 and 1982 from a colony in central Lake Ontario (Scotch Bonnet Island) and from a colony in central Green Bay, Lake Michigan (Big Sister Island) were archived in the Canadian Wildlife Service Specimen Bank. Pooled samples (N = 10) were exhaustively analyzed in 1993 for a wide range of individual chlorinated hydrocarbon contaminant (CHC) compounds: DDT, mirex and chlordane compounds and metabolites, chlorobenzenes (CBzs), dieldrin, chlorostyrenes (CSs), hexachlorocyclohexanes (HCHs), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), and 87 PCB congeners, including the TCDD-like non-ortho and mono-ortho congeners. PCBs and DDTs were the dominant residues in eggs from both Lake Ontario (31-242 mg kg(-1) and 9-64 mg kg(-1)) and Green Bay (34-133 mg kg(-1) and 14-91 mg kg(-1)). SigmaPCBs declined by a factor of 4-5 and DDTs a factor of 4-7 at both colonies between 1971 and 1982. Lake Ontario eggs had significantly higher residues of 2,3,7,8-TCDD (0.2-2.0 microg kg(-1)), HCBz (0.1-4.7 mg kg(-1)), OCS (0.03-0.45 mg kg(-1)), three HpCSs (0.13-0.97 mg kg(-1)), mirex and mirex photodegradation products (2.1-9.2 mg kg(-1)) than Green Bay eggs. HCBz levels in Lake Ontario eggs declined a factor of 40, TCDD and chlorostyrenes a factor of 8-10, and mirex a factor of 4 between 1971-1978. Green Bay eggs had slightly higher levels of chlordane-related compounds, dieldrin and beta-HCH than Lake Ontario eggs. There were no consistent or strong trends in residue levels of these pesticides, PCDDs (except TCDD) and PCDFs in either lake, indicating that rates of input and removal of these CHCs in the lakes were much closer in the early 1970s than was the case for the other compounds.

Animals↗
PubMed2006

Persistent organic pollutants in Alaskan ringed seal (Phoca hispida) and walrus (Odobenus rosmarus) blubber.

Since 1987, the Alaska Marine Mammal Tissue Archival Project (AMMTAP) has collected tissues from 18 marine mammal species. Specimens are archived in the National Institute of Standards and Technology's National Biomonitoring Specimen Bank (NIST-NBSB). AMMTAP has collected blubber, liver and/or kidney specimens from a number of ringed seals (Phoca hispida) from the areas near Nome and Barrow, Alaska and walruses (Odobenus rosmarus) from several locations in the Bering Sea. Thirty-three ringed seal and 15 walrus blubber samples from the NIST-NBSB were analyzed for persistent organic pollutants (POPs). The compounds determined included PCBs (28 congeners or congener groups), DDT and related compounds, hexachlorobenzene (HCB), hexachlorocyclohexane isomers (HCHs), chlordanes, dieldrin, and mirex. POP concentrations in ringed seal blubber were significantly higher in Barrow than in Nome when statistically accounting for the interaction of age and gender; HCB, however, was not statistically different between the two locations. Unlike males, POP concentrations and age were not significantly correlated in females probably as a result of lactational loss. POP concentrations in walrus blubber were lower than in ringed seal blubber for SigmaPCBs, chlordanes, and HCHs, but higher for dieldrin and mirex. POP concentrations in ringed seals and walrus from Alaska provide further evidence that the western Arctic tends to have lower or similar POP concentrations compared to the eastern Canadian Arctic.

Adipose Tissue↗
PubMed2002

In situ hybridization to the Rdl locus on polytene chromosome 3L of Anopheles stephensi.

We are interested in generating a Y-autosome translocation of the Resistance to dieldrin (Rdl) locus in the malaria vector mosquito Anopheles stephensi Liston (Diptera: Culicidae), for use in sterile insect release. To ensure stability of the system, a recombination suppressing inversion can also be induced which encompasses the Rdl locus. As a first step, here we report the cloning of fragments of the Rdl gene from both An. stephensi and An. gambiae Giles using degenerate primers in the polymerase chain reaction. These fragments encode the second membrane-spanning region of the gamma-aminobutyric acid receptor and show high levels of both nucleotide and predicted amino acid identity to other Rdl-like receptors. They confirm that, as in all other arthropod species examined, dieldrin resistance in An. stephensi is associated with replacement of alanine302, in this case with a serine. In situ hybridization of the Rdl probe to polytene chromosomes of An. stephensi localizes the gene to the left arm of chromosome 3 (3L) in region 45C. Rdl localization will enable us to identify chromosomal rearrangements encompassing the Rdl locus and help anchor the genome sequence of An. gambiae to the polytene map.

Amino Acid Sequence↗
PubMedDate not supplied

Concentrations of organochlorine pesticides in milk of Nicaraguan mothers.

Breast-milk samples from 101 mothers from the basin of Rio Aloya, Nicaragua, were collected on two occasions within the first trimester of lactation. Milk samples were analyzed for 13 organochlorine pesticides: (1) p,p'-dichlorophenyldichloroethylene; (2) p,p'-dichlorophenyltrichloroethane; (3) p,p'-dichlorophenyldichlorodiene; (4) alpha-hexachlorocyclohexane; (5) beta-hexachlorocyclohexane; (6) gamma-hexachlorocyclohexane; (7) delta-hexachlorocyclohexane; (8) toxaphene; (9) dieldrin; (10) endrin; (11) aldrin; (12) heptachlor; and (13) heptachlor-epoxide. Organochlorines of the dichlorodiphenylethane class (i.e., p,p'-dichlorodiphenylethane and p,p'-dichlorodiphenylethane) were found in all samples and at the highest mean concentrations observed in the study. Chemicals in the hexachlorocyclohexane family (i.e., alpha- and delta-hexachlocyclohexane) were not found at all (0%), and the other hexachlorocyclohexane compounds (i.e., beta > gamma) were found in less than 6% of the samples. Twenty percent or less of the sample contained chlorInated cyclodienes (i.e., dieldrin > endrin > heptachlor-epoxide > heptachlor). No measurable concentrations of alpha-hexachlorocyclohexane, aldrin, p,p'-dichlorophenyldichlorodiene, and toxaphene were found in the breast milk samples. Analysis of variance demonstrated that only the concentration of p,p'-dichlorophenyldichloroethylene p,p'-dichlorophenyltrichloroethane, and endrin were affected significantly by maternal age. Overall, with the exception of p,p'-chlorophenyldichloroethylene, and p,p'-dichlorophenyltrichloroethane, the mean concentrations of the analyzed pesticides were low. Total p,p'-dichlorophenyltrichloroethane concentrations that exceeded the allowed daily intake set by the World Health Organisation were found in 5.9% of the samples.

Agriculture↗
PubMedDate not supplied

Some dietary predictors of plasma organochlorine concentrations in an elderly German population.

Associations between reported consumption of animal products and chlorinated hydrocarbon concentrations were examined in 297 elderly people who lived in Germany. Consumption of beef and lamb was correlated positively with hexachlorobenzene (HCB), beta-hexachlorocyclohexane (beta-HCH), total polychlorinated biphenyls (PCBs), and total dichloro-diphenyl-trichloroethane (DDT) (r = .13-.19, p < .05). Consumption of saltwater fish was correlated positively with alpha-HCH, dieldrin, and PCBs (r = .12-.26, p < .05). Other univariate predictors were body mass index, plasma cholesterol, pork consumption, poultry consumption, and age. Multivariate linear models of predictors of each chlorinated species were constructed, and some form of meat was used as the main predictor; the sum of all meats (exclusive of fish) was the best predictor of dieldrin and In(alpha-HCH) concentrations. Beef and lamb consumption was a positive predictor of HCB, heptachlor epoxide, total DDT, and beta-HCH. Saltwater fish was the major dietary predictor of PCBs.

Age Factors↗
PubMedDate not supplied

Levels and trends of chlorinated hydrocarbon contaminants in the breast milk of Canadian women.

A total of 210 breast milk samples from 5 different regions across Canada were analyzed for polychlorinated biphenyls (PCBs), hexachloro-1,3-butadiene, ten chlorinated benzenes, two chlorinated naphthalenes, Mirex, photomirex, alpha, beta and gamma hexachlorocyclohexane, alpha and gamma chlordane, oxychlordane, trans-nonachlor, p,p'-DDT and some analogs, heptachlor epoxide, dieldrin and octachlorostyrene. There was no evidence for the presence of hexachloro-1,3-butadiene, Mirex, octachlorostyrene, chlorinated naphthalenes or tetrachlorobenzenes in the breast milk. Residues of other compounds were found in all samples, except 1,2-dichlorobenzene, gamma hexachlorocyclohexane, alpha and gamma chlordane and p,p'-TDE, which were less frequently observed, while o,p'-DDT was only found in approximately one quarter of all samples. Since 1967, a steady decline in heptachlor epoxide, dieldrin and p,p'-DDT and related residues is apparent. At the same time however, there is an apparent increase in PCB residue levels since 1970. This apparent increase should be viewed with some caution, since much of this increase might be attributed to better sampling and analytical techniques. Residue levels of breast milk in Canada were similar to those found in other industrial nations. Regional differences in residue levels appeared to be minimal.

Canada↗
PubMedDate not supplied

Levels of chlorinated hydrocarbon residues in Canadian human breast milk and their relationship to some characteristics of the donors.

A total of 412 breast milk samples from women in all provinces of Canada were analysed for polychlorinated biphenyls, eight chlorinated benzenes, 2,3-dichloronaphthalene, Mirex, alpha, beta, gamma and delta hexachlorocyclohexane, alpha and gamma chlordane, oxychlordane, transnonachlor, p,p'-DDT and some analogues, heptachlor epoxide, dieldrin and octachlorostyrene. No delta-hexachlorocyclohexane, heptachlor or aldrin were found in any of the samples, while median levels of the 1,2,4- and 1,3,5-trichlorobenzene, 1,2,3,4- and 1,2,3,5-tetrachlorobenzenes, gamma chlordane, o,p'-DDT and octachlorostyrene were all less than the minimum detectable level (MDL). All other compounds were present at median levels ranging from < 0.1 to 7.2 ng/g whole milk, but did not occur in all samples. Di to tetrachlorobenzenes, except 1,2,4-trichlorobenzene, 2,3-dichloronaphthalene and alpha-chlordane were observed in < 50% of the samples. From 1967 to 1986 a steady decline of hexachlorobenzene, gamma-hexachlorocyclohexane, DDTs, heptachlor epoxide and dieldrin was observed in Canadian breast milk. In addition, a decrease in some chlorinated benzenes, gamma-hexachlorocyclohexane and PCBs was also observed between 1982 and 1986. Levels of oxychlordane and trans-nonachlor remained constant. Canadian breast milk contamination appears to be one of the lowest among the industrialized nations. Regional and provincial differences in residue levels appeared minimal, although more often samples from Quebec and British Columbia had higher levels of some contaminants, such as oxychlordane, than samples from other provinces. No relationship was found between maternal age and residue levels, but some contaminants, such as PCBs, were significantly higher in the milk of mothers who breastfed their first child as compared to multiparous mothers. Breast milk residue levels were not related to fish consumption.

Adult↗
PubMed1985

Organochlorine residues in finfish from Maryland waters 1976-1980.

Organochlorine pesticide and herbicide levels were monitored in samples of a variety of edible finfish harvested from the Maryland section of the Chesapeake Bay and its tributaries over a five-year period (1976-80). Qualitative and quantitative information was obtained for the various polychlorinated biphenyls (PCB's), heptachlor, alpha-BHC, chlordane, DDD, DDE, DDT, dieldrin, endrin, heptachlorepoxide, lindane, mirex, methoxychlor, aldrin, toxaphene, hexachlorobenzene, kepone and dacthal. In addition to analyses of the flesh of the animals, organochlorine residue levels were determined in roe or gonad tissue of several samples. Striped bass, white perch and yellow perch samples showed significantly higher concentrations of certain of these substances in roe or gonad tissue, especially PCB's, chlordane, DDD and dieldrin. Significantly higher levels of six organochlorine residues were found in the gonad tissue of striped bass; however, similar studies on gonad tissue of American Shad, harvested from the same region, show no such enhancement. Rather, the reverse is true; levels of certain organochlorine residues are higher in flesh tissue. All mean values, and virtually all individual values of organochlorine concentrations in the edible portion of the fish were within the U.S. Food and Drug Administration guideline, where such guidelines have been established.

Animals↗
PubMed2002

The distribution of organochlorine pesticides in marine samples along the Indian Ocean coast of Kenya.

The concentrations of organochlorine residues of lindane, aldrin, alpha-endosulfan, dieldrin, endrin, p,p'-DDE, p,p'-DDD and p,p'-DDT in samples of seawater, sediment, fish and seaweed from different locations along the coast of Kenya are discussed in relation to the geographical location of the sampling sites and potential sources of residue over a period of two years. All sediment samples were found to contain very low levels of organic carbon except those sampled from Sabaki River that had high (4.7%) organic carbon due to greater primary activity. Most of the pesticides residues (112 samples analysed in 1997 and 258 analysed in 1998/99) were detected in fish, water, sediments and seaweed. The concentration of some residues was higher during the wet season than the dry season in 1997, but no marked seasonal variation was observed in 1998/99. Lindane, aldrin, p,p'-DDT and p,p'-DDE were the most frequently observed residues in all samples while alpha-endosulfan, dieldrin, p,p'-DDD and endrin were either present low concentrations or absent in most samples. Water samples had the lowest concentrations of residues (range 0.503 - 9.025 ng g(-1)). Sediments had the second highest levels of pesticides residues with a range of 0.584 - 59.00 ng g(-1) while fish lipid content had the highest levels of residues in 1989/99 with p,p'-DDT concentration of 1011 ng g(-1) and 418 ng g(-1) p,p'-DDD in Siganus rivulatus.

Animals↗
PubMed2002

Monitoring of organochlorine pesticide residues in pikeperch, Stizostedion lucioperca L. in Beysehir Lake (Central Anatolia).

Fishes in Beysehir Lake were analysed to determine organochlorine pesticide residues. The more frequently detected compounds are DDT complex (DDT, DDD, DDE and isomers), total HCH complex (alpha-HCH, beta-HCH and gamma-HCH or lindane), aldrin, dieldrin, endrin and heptachlorine. Eighty five percent of the fish samples were found to be contaminated. While 75% of the total samples were contaminated by one or more HCH isomers, 63% of the organochlorinated pesticide is DDT and its metabolites. Aldrin, dieldrin and endrin are minor pesticides in samples. Heptachlorine was found in only one sample. Despite their presence high concentrations are sporadic, the mean values being less than FAO/WHO maximum recommended limits.

Animals↗
PubMedDate not supplied

Determination of organochlorine pesticides and metabolites in drinking water, human blood serum, and adipose tissue.

Previously published analytical procedures by which drinking water, human blood serum, and adipose tissue may be analyzed for trace amounts of organochlorine pesticides have been modified to permit use of smaller samples. Data on percent recovery, detector sensitivity, and limit of detectability have been collected for each of the three reported procedures. The methodology has been applied to 59 blood samples, 20 drinking water samples, and 10 necropsy adipose tissue samples. Only hexachlorobenzene and dieldrin were detected in water. Hexachlorobenzene, beta-hexachlorocyclohexane, dieldrin, p,p'DDE, and p,p'DDT were present in blood. No heptachlor, heptachlor epoxide, oxychlordane, trans-nonachlor, or o,p'-DDT was found. In.fat, the compounds present in blood plus oxychlordane, heptachlor epoxide, and trans-nonachlor were detected. No heptachlor, aldrin, o,p'-DDT, or alpha- or gamma-chlordane was present. The reported values are representative of the levels of persistent organochlorine pesticides and pesticide metabolites found in 1978 in white female residents of Dade County, Florida.

Adipose Tissue↗
PubMed1986

Organochlorine pesticides in human milk from different areas of Kenya 1983-1985.

Residue levels of the chlorinated hydrocarbons p,p'-DDT (2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane), p,p'-DDE (2,2-bis(p-chlorophenyl)-1,1-dichloroethane), hexachlorobenzene (HCB), alpha-, beta-, and gamma-hexachlorocyclohexane (HCH), aldrin, dieldrin, and polychlorinated biphenyls (PCBs) were determined in human milk of Kenyan mothers living in different areas of Kenya. The main organochlorine contaminants found in all the milk samples analyzed were p,p'-DDT and p,p'-DDE. Great regional differences were found, and mean levels of sum DDT and DDT/DDE ratio ranged from 1.1 to 18.7 mg/kg milk fat and from 0.7 to 5.7, respectively. In general, relatively low residue levels of HCB, alpha-HCH, beta-HCH, aldrin, and dieldrin were detected in 59, 37, 27, 37, and 19%, respectively, of all the milk samples analyzed. Quantifiable residue levels of PCBs and alpha-HCH were not found. The results were examined in relation to differences in living conditions with regard to agricultural activities, dietary habits, and reported use of pesticides in the various sampling areas.

DDT↗
PubMed1988

Effect of selected insecticides on rat brain synaptosomal adenylate cyclase and phosphodiesterase.

Previous reports from our laboratory and others clearly indicated that organochlorine insecticides such as chlordecone and DDT are potent inhibitors of ATPases involved in active ion transport. The present studies were initiated to study the effect of plictran, chlordecone, toxaphene, aldrin, dieldrin, endrin, isodrin, and telodrin on enzymes involved in cyclic AMP metabolism. Rat brain synaptosomes were prepared by Ficoll-sucrose gradient centrifugation method. Adenylate cyclase activity, which is involved in anabolism of cAMP, was determined using the radioactive method by measuring [32P]cAMP formed during hydrolysis of [32P]ATP. Phosphodiesterase activity, which is involved in the catabolism of cAMP, was estimated by measuring [3H]adenosine formed using [3H]cAMP as a substrate. Synaptosomal adenylate cyclase activity was inhibited significantly by plictran with an IC50 of 25 microM, and a maximum inhibition of 30% was observed with 50 microM chlordecone. Toxaphene, aldrin, dieldrin, endrin, isodrin, and telodrin did not affect the adenylate cyclase activity. Similarly, none of the insecticides studied inhibit the activity levels of synaptosomal phosphodiesterase. The significant inhibition of adenylate cyclase observed with plictran might be due to the tin component, since several heavy metals affect cAMP metabolism. The lack of inhibition of adenylate cyclase and phosphodiesterase with other compounds tested clearly supports our postulation that these organochlorine insecticides exert their neurotoxic action by the selective inhibition of ATPases in synaptosomes.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1982

Enzyme histochemical characteristics of spontaneous and induced hepatocellular neoplasms in mice.

Hepatocellular neoplasms are known to differ in enzyme activity from the surrounding non-neoplastic liver. We have compared histochemically the enzyme activity of spontaneous hepatocellular tumors in mice with tumors induced by diethylnitrosamine and dieldrin. Some neoplasms had increased activity, others had decreased enzyme activity, yet other had the same activity as the surrounding liver. Alkaline phosphatase, glucose-6-phosphatase, succinic dehydrogenase and adenosine triphosphatase, as well as glycogen levels were studied. Carcinomas differed from adenomas in having elevated enzyme activity significantly more often than adenomas. However, the carcinomas showed elevated glycogen levels less frequently than adenomas. Histochemically, pulmonary metastases resembled the primary hepatocellular carcinomas from which they were derived. Tumors of dieldrin animals were notable in having increased activity of all the enzymes which we studied more frequently than tumors of diethylnitrosamine animals or of controls. Differences in enzyme activity between the three mouse strains were slight.

Adenosine Triphosphatases↗
PubMed1999

Development of a stably transfected estrogen receptor-mediated luciferase reporter gene assay in the human T47D breast cancer cell line.

Development of an estrogen receptor-mediated, chemical-activated luciferase reporter gene-expression (ER-CALUX) assay was attempted by stable transfection of luciferase reporter genes in a number of cell lines. Stable transfection of the chimeric Gal4 estrogen receptor and luciferase gene constructs in MCF-7 breast cancer and Hepa.1c1c7 mouse hepatoma cell lines, as well as transfection of a newly constructed luciferase reporter gene pEREtata-Luc in the ECC-1 human endometrial cell line, resulted in constitutive, non-estradiol-inducible clones. Stable transfection of pEREtata-Luc in the T47D breast cancer cell line, however, resulted in an extremely sensitive, highly responsive cell line. Following a 24-h exposure to estradiol (E2), stably transfected T47D.Luc cells demonstrated a detection limit of 0.5 pM, an EC50 of 6 pM, and a maximum induction of 100-fold relative to solvent controls. No clear reduction in responsiveness has been found over extended culture periods (50 passages). Anti-estrogens ICI 182,780, TCDD, and tamoxifen inhibited the estradiol-mediated luciferase induction. Genistein, nonylphenol, and o,p'DDT were the most potent (pseudo-)estrogens tested in this system (EC50 100, 260, and 660 nM, respectively). Determination of interactive effects of the (pseudo-)estrogens nonylphenol, o,p'DDT, chlordane, endosulfan, dieldrin, and methoxychlor revealed that, in combination with 3 pM E2, (pseudo-)estrogens were additive. Slightly more than additive effects (less than 2-fold) were found for combinations of dieldrin and endosulfan tested in the range of 3 to 6 microM. At these concentrations, the combination of endosulfan and chlordane demonstrated additive interaction. The ER-CALUX assay with T47D cells can provide a sensitive, responsive, and rapid in vitro system to detect and measure substances with potential (anti-)estrogenic activity.

Biological Assay↗
PubMed1979

Pesticides for locust control.

The factors influencing the choice of insecticides for locust control are effectiveness, safety in use, relative cost, and the formulations available. The relative importance of these factors varies with the scale of control. In small scale control by farmers safety and simplicity are paramount and a BHC dust is commonly used, but in large scale control operations by specialized organizations more toxic formulations ultra-low-volume (u.l.v.) concentrates and methods of application requiring considerable skills can be used. The remarkable effectiveness of dieldrin as a stomach poison appears to be due to its conversion to photodieldrin after application. Cases of poisoning following large scale control operations are rare, and fatalities in man unknown. Alternatives to organochlorine insecticides include fenitrothion, already recommended and used on a large scale against adults. Against nymphs the correct dosage of fenitrothion would cost nearly 11 times as much as that of dieldren. Recent experimental work with new insecticides has included safety tests with domestic animals and measurements of persistence. 1 microgram deposits of cyanofenphos, decamethrin and mecarphon, as well as of dieldrin and photodieldrin, on wheat seedlings left in the open under tropical conditions for two days, killed 80% or more first instar nymphs of the Desert Locust which fed on them.

Animals↗
PubMed1987

Location of genes on chromosome arms in the Anopheles gambiae group of species and their correlation to linkage data for other anopheline mosquitoes.

The use of paracentric inversions as genetic markers in the Anopheles gambiae group of mosquitoes is described. The gene for dieldrin resistance is assigned to chromosome 2 which in turn is correlated to the previous assignment of the gene to linkage group II. The locus of the enzyme phosphoglucomutase 2 (Pgm 2) is similarly assigned to chromosome 2 and evidence is presented for possible linkage between Pgm 2 and dieldrin resistance. There was no linkage or correlation of chromosome 2 and loci of the enzymes superoxide dismutase (Sod) and octanol dehydrogenase (Odh). These genes are therefore assumed to be on chromosome 3 (linkage group III). Evidence that such gene linkage group/chromosome correlations may extend to other species for which chromosome maps and homologies have been worked out is discussed.

Alcohol Oxidoreductases↗