Analysis Of Congeners Research Articles

Persistent organic pollutants (PCBs and DDTs) in small size specimens of bluefin tuna ( Thunnus thynnus) from the Mediterranean Sea (Ionian Sea)

The concentration levels and pattern distribution of polychlorinated biphenyls (PCBs) and organochlorine pesticides (DDTs), were investigated in liver of small size specimens of bluefin tuna ( Thunnus thynnus) from Mediterranean Sea (Ionian Sea). PCB concentrations (average: 526 ng g − 1 lipid wt) were comparable with DDT levels (average: 435 ng g − 1 lipid wt). The specific analysis of PCB congeners revealed a profile dominated by hexa-, penta- and heptachlorinated congeners, while among DDTs, the compounds with the higher concentration was p,p'-DDE, constituting 91.9% of the total DDT. The total 2,3,7,8-TCDD toxic equivalent (TEQs) of coplanar PCBs, including mono- and non- ortho congeners, was 0.55 pg g − 1 wet weight with. The congeners with highest TEQs values were non- ortho congeners followed by mono- ortho ones.

Simultaneous use of gas chromatography/ion trap mass spectrometry ‐ electron capture detection to improve the analysis of bromodiphenyl ethers in biological and environmental samples

Bromodiphenyl ethers (BDEs) are a class of synthetic flame retardants and are widely present in the environment. Analysis of higher BDE congeners has proven to be a challenge. We report the development of a method that enhances their analysis by splitting the eluent of a gas chromatograph (GC) between an electron capture detector (ECD) and an ion trap mass spectrometer (ITMS): 1:10, ECD:ITMS. This allowed the quantitation of the lower molecular weight (MW) BDE congeners (Br1-Br7) with the ITMS and of the higher MW BDEs (Br8-Br10) with the highly sensitive ECD. The IT temperature, ionization mode, and MS/MS parameters (excitation amplitude and stability parameter) were optimized. This method took the advantages of the best detector for the different BDE homologues and was suitable for the analysis of BDEs in environmental and biological samples. Average recoveries were 52-112% for BDEs from spiked sand samples and 57-126% from spiked lard samples after accelerated solvent extraction followed by silica gel and alumina column clean-up. Average recoveries ranged from 51% to 130% for 13C-labeled BDEs spiked in the real and in matrix samples. The method detection limits for specific congeners were 0.18-120 pg/g of the BDEs in animal tissue samples, and 0.05-40 pg/g in soil and indoor dust samples. The utility of the method was demonstrated by analyzing actual harbor seal blubber, indoor dust and soil samples. The concentration of each BDE ranged from non-detectable (nd) to 41 ng/g in the dry soil sample, nd to 1042 ng/g in the indoor dust, nd to 15 ng/g wet weight in the Alaskan harbor seal blubber sample, and 0.02 to 11 ng/microL of the identified 23 of the 42 breakdown products from BDE-209 after zerovalent iron treatment. Finally, an interlaboratory comparison showed high correspondence between the GC/ITMS-ECD method and a GC high-resolution MS system for the analysis of BDEs in soil samples.

Mouse chromosome 9 quantitative trait loci for soft tissue regeneration: Congenic analysis and fine mapping

Development of gene therapies for wound healing will depend on the identification of the genes involved in wound healing and tissue regeneration. Previous quantitative trait loci (QTL) studies in mice using the ear punch model have shown that major QTL exist on chromosome (Chr) 9 for soft tissue regeneration. In this study, we have developed a congenic line that contains the Chr 9 QTL chromosomal region from super healer MRL/MpJ in the genomic background of poor-healing SJL/J. The phenotypic effect of this QTL was confirmed in male mice, where the congenic line has shown significant healing improvement over SJL. Fine mapping of the Chr 9 QTL region with 23 markers at an average distance of 4.2 Mb using a total of 1,564 MRL/MpJ x SJL/J F(2) mice revealed the presence of at least three QTL peaks, implying that three separate loci may contribute to the phenotypic effect of this QTL. Based on the 2-LOD intervals, the total QTL region was confined to a combined length of no more than 28.2 Mb. Application of a Bayesian shrinkage estimation indicated that a major locus was located in a region of just 1.3 Mb.

Is There a Need to Revise Health Canada’s Human PCB Guidelines?

This article assesses if there is a need to revise Health Canada's polychlorinated biphenyl (PCB) guidelines for whole blood given that plasma is typically favoured over whole blood for analysis, technological advancements in analytical methods have occurred, and the congener profiles of PCBs in the environment continue to change due to degradation and re-compartmentalization. Canadian epidemiological and exposure studies within the last 11 years were examined in order to determine the dominant method of PCB reporting and the human tissues or fluids analyzed. In all but one study, PCBs were analyzed on a congener basis. In the cases where an Aroclor equivalency was reported, the result was calculated using an Aroclor estimation equation based on several PCB congeners. To date, a wide variety of tissues and fluids are still being analyzed; however, only one study performed the analysis using whole blood, the basis of Health Canada's guidelines. Additionally, congener profiles in the environment are changing due to degradation and re-compartmentalization; therefore, guidelines should reflect this change. The reporting of whole blood PCB levels in Canada is a rare practice, and reporting PCBs solely as an Aroclor mixture can result in false non-detection; however, the Health Canada guidelines are based on Aroclor 1260 levels in whole blood. PCB congener analysis by gas chromatography/mass spectroscopy results in greater accuracy with greater sensitivity and limit of detection for the samples when compared to gas chromatography alone. Further, Aroclor equivalency can be estimated from congener analysis results. No other nation has yet prescribed PCB guidelines in human fluids or tissues; this is likely due to the uncertainty associated with PCB health risk assessment. Given the findings, whole blood PCB guidelines must be revised in order to reflect advances in the medical sciences.

Associations between Prenatal Exposure to Polychlorinated Biphenyls and Neonatal Thyroid-Stimulating Hormone Levels in a Mexican-American Population, Salinas Valley, California

BackgroundStudies have reported that prenatal exposure to polychlorinated biphenyls (PCBs) may alter neurodevelopment in both humans and animals. Furthermore, prenatal exposure to some PCB congeners and commercial mixtures has been shown to decrease free and total thyroxine (T4) blood levels in animals. Because thyroid hormones (TH) are essential for normal neurologic development, it has been suggested that the deleterious neurodevelopmental effect of PCBs may occur through TH disruption. PCBs may in turn affect TH levels by inducing the microsomal enzyme uridinediphosphate glucuronosyltransferase (UDP-GT), which is involved in TH elimination.ObjectivesOur goals were to group PCB congeners based on their potential to induce microsomal enzymes in animals, and to examine the relationship between neonatal TSH levels and prenatal exposure to PCB congeners grouped according to their structure and potential mechanisms of action.MethodsWe measured the concentration of 34 PCB congeners in serum samples collected from 285 pregnant women and the thyroid-stimulating hormone (TSH) levels in their children’s blood collected shortly after birth.ResultsWe found no association between the sum of PCB congeners, the toxic equivalents, or structure-based groupings (mono- or di-ortho substituted congeners), and TSH blood concentration. However, we found a positive association between the sum of congeners suspected to be UDP-GT inducers (more specifically cytochrome P450 2B inducers) in animals and neonatal TSH levels. In individual congener analyses, PCBs 99, 138, 153, 180, 183, 187, 194, and 199 were positively associated with neonatal TSH levels after adjustment for covariates. PCBs 194 and 199 remained significant after adjustment for multiple hypothesis testing.ConclusionsOur results support grouping PCB congeners based on their potential mechanism of action of enzyme induction when investigating associations with TH. Findings also suggest that PCBs affect TH homeostasis even at the low background level of exposure found in the CHAMA-COS (Center for the Health Assessment of Mothers and Children of Salinas) population.

Cometabolic degradation of polychlorinated biphenyls (PCBs) by axenic cultures of Ralstonia sp. strain SA-5 and Pseudomonas sp. strain SA-6 obtained from Nigerian contaminated soils

Substantial metabolism of 2,3,4,5-tetrachlorobiphenyl (2,3,4,5-tetraCB) and 2,3′,4′,5-tetraCB by axenic cultures of Ralstonia sp. SA-5 and Pseudomonas sp. SA-6 was observed in the presence of biphenyl supplementation, although, the strains were unable to utilize tetrachlorobiphenyls as growth substrate. The former was more amenable to aerobic degradation (∼70% degradation) than the latter (22–45% degradation). Recovery of 2,5-chlorobenzoic acid and chloride from 2,3′,4′,5-tetraCB assay is an indication of initial dioxygenase attack on the 3,4-dichlorophenyl ring. The PCB-degradative ability of both strains was also investigated by GC analysis of individual congeners in Aroclor 1242 (100 ppm) following 12-day incubation with washed benzoate-grown cells. Results revealed two different catabolic properties. Whereas strain SA-6 required biphenyl as inducer of the degradation activity, such induction was not required by strain SA-5. Nearly all the detectable congeners in the mixture were extensively degraded (% reduction in ECD area counts for individual congeners ranged from 50.0 to 100% and 14.2 to 100%, respectively, for SA-5 and SA-6). The two strains exhibited no noticeable specificity for congeners with varying numbers of chlorine substitution and positions. The degradative competence of these isolates most especially SA-5 makes them among the most versatile PCB-metabolizing organisms yet reported.

Taxonomic review of fossil Proboscidea (Mammalia) from Langebaanweg, South Africa

Comparative morphological and metric study of proboscidean dental fossils from the Quartzose (QSM) and Pelletal Phosphate (PPM) Members of the Varswater Formation at Langebaanweg, South Africa identifies the presence in the fauna of an anancine gomphothere and two species of elephant. The gomphothere, from the QSM and PPM, displays a unique combination of primitive and derived molar features, and consequently is placed in a new species (Anancus capensis sp. nov.) that is regionally distinct from other African species of Anancus. A new species of loxodont elephant (Loxodonta cookei sp. nov.) is identified from the PPM, distinguished from penecontemporaneous L. adaurora by having anterior and posterior accessory central conules that contribute to the formation of strong median sinuses throughout its molar crowns. It is further differentiated from other loxodont elephants by its primitive retention of permanent premolars, lower crown height, fewer molar plates, thicker enamel, and lower lamellar frequency, and extends the L. exoptata-L. africana lineage back into the late Miocene. A second elephant species, from the QSM, is referable to Mammuthus subplanifrons, and represents the most archaic stage of mammoth evolution. The elephants appear to have been more cosmopolitan in distribution than the gomphothere. Together, these taxa support a latest Miocene-early Pliocene age of ca. 5.0 Ma for the Vars-water Formation. Based on isotopic analyses of congeners from other African sites, it may be inferred from the occurrence of these taxa that open conditions were present locally and abundant grazing resources were available in the ecosystems of Langebaanweg during the time of deposition of the QSM and PPM.

Fine mapping reveals sex bias in quantitative trait loci affecting growth, skeletal size and obesity-related traits on mouse chromosomes 2 and 11.

Previous speed congenic analysis has suggested that the expression of growth and obesity quantitative trait loci (QTL) on distal mouse chromosomes (MMU) 2 and 11, segregating between the CAST/EiJ (CAST) and C57BL/6J-hg/hg (HG) strains, is dependent on sex. To confirm, fine map, and further evaluate QTL x sex interactions, we constructed congenic by recipient F2 crosses for the HG.CAST-(D2Mit329-D2Mit457)N(6) (HG2D) and HG.CAST-(D11Mit260-D11Mit255)N(6) (HG11) congenic strains. Over 700 F2 mice were densely genotyped and phenotyped for a panel of 40 body and organ weight, skeletal length, and obesity-related traits at 9 weeks of age. Linkage analysis revealed 20 QTL affecting a representative subset of phenotypes in HG2DF2 and HG11F2 mice. The effect of sex was quantified by comparing two linear models: the first model included sex as an additive covariate and the second incorporated sex as an additive and an interactive covariate. Of the 20 QTL, 8 were sex biased, sex specific, or sex antagonistic. Most traits were regulated by single QTL; however, two closely linked loci were identified for five traits in HG2DF2 mice. Additionally, the confidence intervals for most QTL were significantly reduced relative to the original mapping results, setting the stage for quantitative trait gene (QTG) discovery. These results highlight the importance of assessing the contribution of sex in complex trait analyses.

PCB levels in European eel (Anguilla anguilla) from two coastal lagoons of the Mediterranean

Eels are exposed to pollutants due to their unusual life cycle and are vulnerable to contamination associated with sediment due to their diet, feeding habits and territoriality. Since the 1980s, a decline in American and European eel populations has been recorded. The causes of this decline still are unknown but pollution from domestic and industrial effluents is known to be involved. Since little data is available on PCB contamination in eels from Italian waters, PCBs were measured in muscle of Anguilla anguilla captured in 2001 in two brackish ecosystems of the Mediterranean: the lagoons of Orbetello and Santa Giusta (Italy). PCBs were higher in samples from Orbetello lagoon than in those detected from Santa Giusta lagoon (P < 0.05). Congener and isomer analyses indicated Aroclor 1260 as a likely source of PCBs in the Orbetello and Santa Giusta samples. Only the toxic equivalents (TEQs) of mono-ortho PCBs were calculated.

Occurrence of polychlorinated biphenyls (PCBs) in the Soulou stream in the power generation area of Eordea, northwestern Greece

The occurrence of polychlorinated biphenyls (PCBs) was investigated in the Soulou stream in the area of Eordea, northwestern Greece, receiving the effluents of two lignite burning power plants. The study was carried out after an accidental fire in one of the power plants during which losses of an amount of Aroclor 1232 were recorded. PCBs were determined in water and sediment samples collected from the wastewater treatment unit of the power plant and various points across the stream. Concentrations of PCBs were in the same order of magnitude as in other surface waters and sediments previously found in the Greek territory. The sum concentrations of seven PCBs (#28, #52, #101, #118, #138, #153, #180) varied between 94 and 206 ng l −1 in waters, and between 67 and 500 ng g −1 in sediments. Profile analysis of PCB congeners revealed large differences between waters and sediments, showing also significant dissimilarity with the profile of Aroclor 1232.

Supervised Pattern Recognition Procedures for Discrimination of Whiskeys from Gas Chromatography/Mass Spectrometry Congener Analysis

The volatile congener analysis of 52 commercialized whiskeys (24 samples of single malt Scotch whiskey, 18 samples of bourbon whiskey, and 10 samples of Irish whiskey) was carried out by gas chromatography/mass spectrometry after liquid-liquid extraction with dichloromethane. Pattern recognition procedures were applied for discrimination of different whiskey categories. Multivariate data analysis includes linear discriminant analysis (LDA), k nearest neighbors (KNN), soft independent modeling of class analogy (SIMCA), procrustes discriminant analysis (PDA), and artificial neural networks techniques involving multilayer perceptrons (MLP) and probabilistic neural networks (PNN). Classification rules were validated by considering the number of false positives (FPs) and false negatives (FNs) of each class associated to the prediction set. Artificial neural networks led to the best results because of their intrinsic nonlinear features. Both techniques, MLP and PNN, gave zero FPs and zero FNs for all of the categories. KNN is a nonparametric method that also provides zero FPs and FNs for every class but only when selecting K = 3 neighbors. PDA produced good results also (zero FPs and FNs always) but only by selecting nine principal components for class modeling. LDA shows a lesser classification performance, because of the building of linear frontiers between classes that does not apply in many real situations. LDA led to one FP for bourbons and one FN for scotches. The worse results were obtained with SIMCA, which gave a higher number of FPs (five for both scotches and bourbons) and FNs (six for scotchs and two for bourbons). The possible cause of these findings is the strong influence of class inhomogeneities on the SIMCA performance. It is remarkable that in any case, all of the methodologies lead to zero FPs and FNs for the Irish whiskeys.

Site Specific PCB-Correlated Interspecies Differences in Organ Somatic Indices

We correlated site specific differences in the organ somatic indices of nestlings of five passerine species (tree swallow, red-winged blackbird, house wren, Carolina chickadee, and eastern bluebird) with the degree of polychlorinated biphenyls (PCB) exposure in ovo and post-hatching. The birds were exposed to PCBs at or downstream of four PCB-contaminated sites. Of the organs evaluated for this paper, brain, bursa, heart, kidneys, lungs, pancreas, spleen, stomach, and thyroid varied significantly (p<0.05) or marginally significantly (0.05<p<0.11) between sites for at least one species. Differences were noted in the direction of the mean SI change (increased or decreased with increasing contaminant exposure by site) between different species for brain, lung, pancreas, spleen and thyroids. Our results indicated that no single passerine species fully represented the response characteristics observed in these species, and no single difference in organ SI should be used in ecotoxicological evaluations. Further, it is critical to include congener analysis in any evaluations since some endpoints in some species correlate well with total TEQs, and some with total PCBs and not TEQs. Some samples containing biologically significant levels of dioxin-like congeners would have been "non-detects" for total PCBs using common analytical methods.

Three Stages of a Biofilm Community Developing at the Liquid-Liquid Interface between Polychlorinated Biphenyls and Water

Soil contaminated with polychlorinated biphenyls (PCB) was used as an inoculum to grow a complex biofilm community on PCB oil (Aroclor 1242) on a substratum (Permanox). The biofilm was monitored for 31 days by confocal laser scanning microscopy, community fingerprinting using single-strand conformational polymorphism (SSCP), amplicons of the 16S rRNA genes, and chemical analyses of the PCB congeners. SSCP analysis of the young biofilm revealed a rather diverse microbial community with species of the genera Herbaspirillum and Bradyrhizobium as dominant members. The biofilm developing on the PCB droplets displayed pronounced stages of PCB degradation and biofilm development not described before from pure-culture experiments. The first step was the colonization of the substratum while the PCB oil was hardly populated. When a certain density of bacteria was reached on the Permanox, the PCB was colonized, but soon the degradation of the congeners was markedly reduced and many cells were damaged, as seen by LIVE/DEAD staining. Finally, the biofilm formed aggregates and invaded the PCB oil, showing lower numbers of damaged cells than before and a dramatic increase in PCB degradation. This sequence of biofilm formation is understood as a maturation process prior to PCB oil colonization. This is followed by a thin biofilm on the PCB droplet, an aggregation process forming pockets in the PCB, and finally an invasion of the biofilm into the PCB oil. Only the mature biofilm showed degradation of pentachlorinated PCB congeners, which may be reductively dechlorinated and the resulting trichlorobiphenyls then aerobically metabolized.

Polychlorinated biphenyls (PCBs) levels and distribution in Ethiope and Benin Rivers of the Niger Delta, Nigeria: surface water and sediments

Concentrations of polychlorinated biphenyls (PCBs) were determined in surface water and sediment samples from the Ethiope and Benin Rivers of the western Niger Delta. Specific individual congener analysis of PCBs was undertaken using a HPGC, series 6890. Mean levels of ΣPCBs (sum of eight congeners) in surface water samples from river stations ranged from 1.50–1.5 µg l−l (Ethiope River) and 0.03–2.93 µg l−l (Benin River). Levels in sediment samples were higher with mean concentration of PCBs ranging from 0.73–6.7 ng g−l (Ethiope River) and 0.35–15.15 ng g−l (Benin River). The null hypothesis of normality was rejected at P > 0.05 indicating a significant difference between the matrices. The principal component analysis (PCA) showed that patterns of distribution of individual congeners differed between the stations and matrices. Although low levels of PCBs were observed in the water samples, some stations, had values exceeding the USEPA PCBs limits in surface waters (0.0005 mgl−l) and water quality criterion for chronic exposure (79 pgl) through drinking water and fish ingestion. This observation makes PCBs, contaminants of concern in western Niger Delta aquatic ecosystem.

Modifier loci condition autoimmunity provoked by Aire deficiency

Loss of function mutations in the autoimmune regulator (Aire) gene in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy patients and mutant mice lead to autoimmune manifestations that segregate as a monogenic trait, but with wide variation in the spectrum of organs targeted. To investigate the cause of this variability, the Aire knockout mutation was backcrossed to mice of diverse genetic backgrounds. The background loci strongly influenced the pattern of organs that were targeted (stomach, eye, pancreas, liver, ovary, thyroid, and salivary gland) and the severity of the targeting (particularly strong on the nonobese diabetic background, but very mild on the C57BL/6 background). Autoantibodies mimicked the disease pattern, with oligoclonal reactivity to a few antigens that varied between Aire-deficient strains. Congenic analysis and a whole genome scan showed that autoimmunity to each organ had a distinctive pattern of genetic control and identified several regions that controlled the pattern of targeting, including the major histocompatibility complex and regions of Chr1 and Chr3 previously identified in controlling type 1 diabetes.

Congener profiles of PCDDs, PCDFs, and dioxin-like PCBs in the breast milk samples in Tokyo, Japan

Exposure to dioxins has raised much public concern recently. We determined the congeners’ distribution of polychlorinated-dibenzo- p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in the breast milk samples collected in Tokyo, Japan. Breast milk was taken from 240 mothers, 30 days after delivery in 1999 and 2000 in Tokyo, Japan. The actual concentration and TEQ concentration of PCDDs (14 congeners), PCDFs (15 congeners), and dl-PCBs (12 congeners), and each congener’s contribution to the total TEQ level were calculated. Among all the samples, PCDDs accounted for 34.8%, PCDFs accounted for 23.5%, dl-PCBs accounted for 41.7%, which was also similar in the breast milk from the primiparae and secundiparae. The main contributors to the total TEQ with increasing percentages were 2,3,4,7,8-PeCDF, 1,2,3,7,8-PeCDD and 3,3′,4,4′,5-PCB (#126), and they accounted for more than 65% of the total TEQ. Detailed congener analysis in breast milk samples is effective to understand dioxin sources.

Dioxin concentration in human milk in Hebei province in China and Tokyo, Japan: Potential dietary risk factors and determination of possible sources

Very limited information is available on body burdens and environmental levels of dioxins and dioxin-like PCBs (dl-PCBs) in mainland China. In the current studies, human milk samples were collected from 30 breastfeeding mothers in Shijiazhuang city (industrialized) and 11 in the Tanshan countryside (agricultural) of Hebei Province in northern China. An additional 20 samples were obtained from mothers in Tokyo, Japan. PCDDs, PCDFs, and dl-PCBs in human milk were analyzed by high-resolution gas chromatography/high-resolution mass spectrometry. Our results show that arithmetic means for body burdens of PCDDs/Fs and dl-PCBs in Hebei were 3.6 and 1.9 pg TEQ g −1 fat, respectively, which were only about one fourth of the levels in Japan. In addition, no difference was found in the chemical levels except dl-PCBs between the urban and rural areas. Based on the results of an in-person interview of the Chinese mothers using a 59-item questionnaire, freshwater fish consumption was found to correlate with the body burden of dioxins. Principal component analysis of dioxin congeners revealed that the patterns of dioxins in the Hebei urban and rural areas are quite similar; however, they are clearly different from those in Japan. Collectively, our results suggest that the lower body burdens of dioxin in Hebei may be due in part to the relatively slow industrialization and a lower consumption of marine foods. Finally, the results indicate that comprehensive monitoring of dioxins and dl-PCBs in humans as well as in the environment and foods is necessary in China.

Conditioning the genome identifies additional diabetes resistance loci in Type I diabetes resistant NOR/Lt mice

While sharing the H2g7 MHC and many other important Type I diabetes susceptibility (Idd) genes with NOD mice, the NOR strain remains disease free due to resistance alleles within the approximately 12% portion of their genome that is of C57BLKS/J origin. Previous F2 segregation analyses indicated multiple genes within the 'Idd13' locus on Chromosome 2 provide the primary component of NOR diabetes resistance. However, it was clear other genes also contribute to NOR diabetes resistance, but were difficult to detect in the original segregation analyses because they were relatively weak compared to the strong Idd13 protection component. To identify these further genetic components of diabetes resistance, we performed a new F2 segregation analyses in which NOD mice were outcrossed to a 'genome-conditioned' NOR stock in which a large component of Idd13-mediated resistance was replaced with NOD alleles. These F2 segregation studies combined with subsequent congenic analyses confirmed the presence of additional NOR resistance genes on Chr. 1 and Chr. 4, and also potentially on Chr. 11. These findings emphasize the value for diabetes gene discovery of stratifying not only MHC loci conferring the highest relative risk but also as many as possible of the non-MHC loci presumed to contribute significantly.

Several Genes Contribute to the Production of Autoreactive B and T Cells in the Murine Lupus Susceptibility LocusSle1c

The systemic lupus erythematosus 1 (Sle1) locus mediates the loss of tolerance to nuclear Ags in the NZM2410 mouse model of lupus through intrinsic defects in both B and T cells. Congenic analysis has shown that Sle1 corresponds to at least three genetic loci, Sle1a, Sle1b, and Sle1c. Telomeric Sle1c is associated with abnormal B cell responses to subthreshold stimulation with anti-IgM and C3d and with decreased T-dependent humoral immune responses. We have proposed that these phenotypes resulted from polymorphisms in the C3 complement receptor Cr2 gene. We have also found that Sle1c was associated with the production of histone-specific autoreactive CD4(+) T cells, which correlated with higher activation and proliferative responses, and a reduction in the CD4(+)CD25(+)CD62L(+)forkhead/winged helix transcription factor gene (Foxp3(+)) compartment. In this study we showed, using congenic recombinants, that the decreased humoral immune response and impaired GC formation map to the NZM2410 Cr2 allele. A chronic graft-vs-host disease model also showed that Sle1c produces significantly more autoreactive B cells than B6 controls, and that this phenotype maps to two regions excluding the Cr2 gene. Mixed bone marrow chimera demonstrated that the increased activation, proliferative response, and reduced regulatory T cell compartment were intrinsic to Sle1c-expressing CD4(+) T cells. These phenotypes mapped to the same two loci identified with the chronic graft-vs-host disease model, excluding the Cr2 region. Overall, these results show that Sle1c results in the production of autoreactive B and T cells through the expression of three different genes, one of which is consistent with Cr2, based on the phenotypes of the Cr2-deficient mice, and the other two corresponding to as yet unidentified genes.

Analysis of 4-nonylphenols, phthalates, and polychlorinated biphenyls in soils and biosolids

When sewage sludge is added to agricultural land, organic chemicals contaminants are also added. The fate of these chemicals, particularly those shown to have oestrogenic potential, has received much research and regulatory interest in recent years. A method was developed for the analysis of 4-nonylphenols, phthalates, and PCB congeners in soils, mesophilic anaerobially digested dewatered (MADD) sewage sludge, and MADD sludge-amended soil. After Soxhlet-extraction, the 4-nonylphenols and phthalates were separated from the PCBs on an isolute cyanopropyl SPE cartridge and analysed by GC–MS directly. The PCBs were acid treated on a Bakerbond PCB-A cartridge, then passed through a gel filtration column of Biobeads SX-3 resin, before GC–MS analysis. The method was successfully validated and then used for routine analysis, where average recoveries of the surrogate standards were 83 ± 17% (4- n-heptylphenol), 96 ± 11% (dimethyl- tere-phthalate), 101 ± 12% (dibenzyl-phthalate), and 79 ± 13% (PCBs 6, 54, 104, 155, and 198).