Chemical Xenobiotics Research Articles

Double-Edged Sword Effect of Diet and Nutrition on Carcinogenic Molecular Pathways in Breast Cancer.

Environmental exposure to a mixture of chemical xenobiotics acts as a double-edged sword, promoting or suppressing tumorigenesis and the development of breast cancer (BC). Before anything else, we are what we eat. In this review, we highlight both "the good" and "the bad" sides of the daily human diet and dietary patterns that could influence BC risk (BCR) and incidence. Thus, regularly eating new, diversified, colorful, clean, nutrient-rich, energy-boosting, and raw food, increases apoptosis and autophagy, antioxidation, cell cycle arrest, anti-inflammation, and the immune response against BC cells. Moreover, a healthy diet could lead to a reduction in or the inhibition of genomic instability, BC cell stemness, growth, proliferation, invasion, migration, and distant metastasis. We also emphasize that, in addition to beneficial compounds, our food is more and more contaminated by chemicals with harmful effects, which interact with each other and with endogenous proteins and lipids, resulting in synergistic or antagonistic effects. Thus, a healthy and diverse diet, combined with appropriate nutritional behaviors, can exert anti-carcinogenic effects and improve treatment efficacy, BC patient outcomes, and the overall quality of life of BC patients.

Fatty Acid Elongase Gene PcELO7 is Essential for Lipid Accumulation and Fecundity of Panonychus citri (Acari: Tetranychidae).

RNA interference (RNAi) has been proposed as a promising strategy for sustainable and ecofriendly pest control. The insect cuticle lipids were deposited on the body surface and functioned as a defense against chemical xenobiotics. They consisted of aliphatic compounds, including free fatty acids (FFAs). However, elongase of very long chain fatty acids (ELOs) is essential for FFA biosynthesis; the function of ELO is still unknown in many arthropods, including Panonychus citri (P. citri). In this study, three ELOs were cloned. Developmental-specific mRNA expression results revealed that three PcELOs were highly expressed in egg and adult females. Whereas PcELO7 was dominantly expressed in adult females. Under spirobudiclofen stress, ELOs mRNA expression had different changes, and PcELO7 was down-regulated. The silencing of PcELO7 resulted in a dramatic reduction of oviposition and hatchability. Significant reduction of FFA contents was also examined within PcELO7-repressed P. citri. In addition, we found that PcELO7 mRNA levels were related to fecundity and could affect triacylglycerol (TG) contents. The findings demonstrated that the introduction of dsPcELO7 via oral feeding induced the RNA interference-mediated silencing of a special target gene and could result in mortality and reproduction. In conclusion, PcELO7 is a special RNAi target for P. citri control, and its lethal mechanism might be disturbing lipids biosynthesis.

ЕКОЛОГІЧНІ АСПЕКТИ СТАНУ УРБАНОЗЕМІВ

Physical and chemical transformation is typical for urban soils, that considerably aggravate their agroecological functions. The purpose of this work consists in ecological assessment of the current state of urban soils of Cherkasy. The city soils have a significant man-made load and contain many chemical xenobiotics. Diagnostics of the indicators of urban soils, which are crucial for assessing their ecological status and their agroecological functions, will provide an opportunity to determine the optimal and critical values for the sustainable functioning of urban landscapes and to propose the most effective and timely measures to be implemented. The urban soils analysis has shown that the humus content varies within the range of 0.03- 3.01 %, with an average value of 0.84 %, a standard deviation of 0.67, a dispersion of 0.41, a variation coefficient of 76 %. 6.25 % of the studied soil samples have insufficient supply of humus (2-4 %), 25 % have poor supply (1-2 %) and 69 % have extremely poor supply (less than 1 %). The active acidity (pH) varies from 6.45 to 10.90 with an average value of 7.20, a standard deviation of 0.83, a dispersion of 0.69, a variation coefficient of 11 %. The soils mostly have a weakly alkaline and neutral environment. The oxidation-reducing potential varies from 252 to 287 mV, with an average value of 262 mV (standard deviation of 7.3, a dispersion of 52.6, a variation coefficient of 3 %). The ratio of Ca2+ and Mg2+cations in soil adsorption complex is not optimal. The content of Ca2+ ranges from 3.80 to 10.12 mg-eq./100 g of soil with an average value of 6.60, a standard deviation of 1.66, a dispersion of 2.77, a variation coefficient of 25 %. The content of Mg2+ varies from 0.0 to 10.40 mg-eq./100 g of soil with an average value of 3.14 (standard deviation of 2.50, a dispersion of 6.26, a variation coefficient of 80 %). The content of K+ ranges from 0.12 to 6.20 with an average value of 0.59 mg-eq./100 g of soil, a standard deviation of 0.67, a dispersion of 1.39, a variation coefficient of 95 %. The soils have a significant deviation from optimal values and that characterizes them as anthropogenically and technogenically urbanized. There is a need in soil gypsuming, organic fertilizers, moisture supply and reduction of moisture evaporation, improvement of aeration conditions.

Динамика накопления химических ксенобиотиков в организме животного и механизм их выведения

Динамика накопления химических ксенобиотиков в организме животного и механизм их выведения

The membrane-associated MUC1 improves adhesion of salivary MUC5B on buccal cells. Application to development of an in vitro cellular model of oral epithelium

ObjectivesThe mucosal pellicle is a thin layer of salivary proteins, mostly MUC5B mucins, anchored to epithelial oral cells. This pellicle is involved in protection of oral mucosae against abrasion, pathogenic microorganisms or chemical xenobiotics. The present study aimed at studying the involvement of MUC1 in mucosal pellicle formation and more specifically in salivary MUC5B binding using a cell-based model of oral epithelium. DesignMUC1 mRNAs were not detected in TR146 cells, and therefore a stable cell line named TR146/MUC1 expressing this protein was developed by transfection. TR146 and TR146/MUC1 were incubated with human saliva in order to evaluate retention of MUC5B by epithelial cells. ResultsThe cell surface of both TR146 and TR146/MUC1 was typical of a squamous non-keratinized epithelium, with the presence of numerous microplicae. After incubation for 2h with saliva diluted in culture medium (1:1) and two washes with PBS, saliva deposits on cells appeared as a loose filamentous thin network. MUC5B fluorescent immunostaining evidenced a heterogeneous lining of confluent cell cultures by this salivary mucin but with higher fluorescence on TR146/MUC1 cells. Semi-quantification of MUC5B bound to cells confirmed a better retention by TR146/MUC1, evaluated by Dot Blot (+34.1%, p<0.05) or by immunocytochemistry (+44%, p<0.001). ConclusionThe membrane-bound mucin MUC1 is a factor enhancing the formation of the mucosal pellicle by increasing the binding of salivary MUC5B to oral epithelial cells. An in vitro model suitable to study specifically the function and properties of the mucosal pellicle is proposed.

Ongoing activation of autoantigen-specific B cells in primary biliary cirrhosis.

The serologic hallmark of primary biliary cirrhosis (PBC), the antimitochondrial response to the E2 component of the pyruvate dehydrogenase complex (PDC-E2), has unique features, including continuous high titers of immunoglobulin M (IgM) and IgG reactivity throughout all stages of disease, capable not only of target enzyme inhibition, but also crossreactive with chemical xenobiotics that share molecular homology with the inner lipoyl domain of PDC-E2; such chemicals have been proposed as potential etiological agents. We used flow cytometry and enzyme-linked immunospot assay (ELISPOT) to examine B-cell subsets in 59 subjects, including 28 with PBC, 13 with primary sclerosing cholangitis (PSC), and 18 healthy controls. Strikingly, in PBC, although there were no significant differences in B-cell phenotype subpopulations, 10% of the total IgG and IgA plasmablast population and 23% of the IgM plasmablast population were uniquely reactive with PDC-E2, detected in the CXCR7+ CCR10low plasmablast population. In contrast, plasmablast reactivity to a control antigen, tetanus toxoid, was minimal and similar in all groups. Additionally, we isolated plasmablast-derived polyclonal antibodies and compared reactivity with plasma-derived antibodies and noted a distinct noncirculating tissue source of xenobiotic crossreacting antibodies. The high levels of autoantigen specific peripheral plasmablasts indicate recent activation of naive or memory B cells and a continuous and robust activation. The presence of CXCR7+ CCR10low PDC-E2-specific ASCs suggests a mechanistic basis for the migration of circulating antigen specific plasmablasts to the mucosal epithelial ligands CXCL12 and CCL28. Our findings suggest a sustained rigorous B-cell response in PBC, likely activated and perpetuated by cognate autoantigen.

Animal models of primary biliary cirrhosis.

Within the last decade, several mouse models that manifest characteristic features of primary biliary cirrhosis (PBC) with antimitochondrial antibodies (AMAs) and immune-mediated biliary duct pathology have been reported. Here, the authors discuss the current findings on two spontaneous (nonobese diabetic autoimmune biliary disease [NOD.ABD] and dominant negative transforming growth factor-β receptor II [dnTGFβRII]) and two induced (chemical xenobiotics and microbial immunization) models of PBC. These models exhibit the serological, immunological, and histopathological features of human PBC. From these animal models, it is evident that the etiology of PBC is multifactorial and requires both specific genetic predispositions and environmental insults (either xenobiotic chemicals or microbial), which lead to the breaking of tolerance and eventually liver pathology. Human PBC is likely orchestrated by multiple factors and hence no single model can fully mimic the immunopathophysiology of human PBC. Nevertheless, knowledge gained from these models has greatly advanced our understanding of the major immunological pathways as well as the etiology of PBC.

Gene Frequencies of the Human GSTT1 (Null Allele) and GSTP1 (Ile105Val) Polymorphisms among South Indian Populations

Background: Glutathione S-transferases (GSTs) are members of the phase II biotransformation enzymes that play a key role in cellular detoxification of chemical carcinogens and xenobiotics. Variations at GST genes have been reported in different human populations, and some association studies have reported increased risk for cancers and other disease end points. The present study was conducted to investigate the allele frequency variations in south Indian populations. Methods: GSTT1 null allele and GSTP1 Ile105Val polymorphisms were genotyped in two hundred and twelve subjects (aged 34 to 60 years old) belong to six populations using PCR and PCR-RFLP techniques respectively. Results: Both GSTT1 ins-del and GSTP1 Ile105Val are polymorphic in all populations. GSTP1 Ile105Val followed the Hardy-Weinberg equilibrium. The GSTT1 null allele frequencies ranged from 11.6% to 22.2% and GSTP1 Ile105Val “Val” allele frequency ranged from 20.0% to 38.2% in the study populations. HapMap data showed the highest frequency of Val105 allele in African populations followed by European populations. East Asian populations showed the lowest frequency of Val105 allele. Conclusion: The variations observed in allelic distribution of GST genes may presumably be due to the selective pressure exerted on populations of that region. In conclusion, the present study reports the frequency of GSTT1 null allele and GSTP1 Ile105Val polymorphisms in Indian populations which provides foundation for potential epidemiological and clinical studies.

Environment and primary biliary cirrhosis: Electrophilic drugs and the induction of AMA

Environmental stimulation is a major factor in the initiation and perpetuation of autoimmune diseases. We have addressed this issue and focused on primary biliary cirrhosis (PBC), an autoimmune disease of the liver. Immunologically, PBC is distinguished by immune mediated destruction of the intra hepatic bile ducts and the presence of high titer antimitochondrial autoantibodies (AMA) directed against a highly specific epitope within the lipoic acid binding domain of the pyruvate dehydrogenase E2 subunit (PDC-E2). We submit that the uniqueness of AMA epitope specificity and the conformational changes of the PDC-E2 lipoyl domain during physiological acyl transfer could be the lynchpin to the etiology of PBC and postulate that chemical xenobiotics modification of the lipoyl domain of PDC-E2 is sufficient to break self-tolerance, with subsequent production of AMA in patients with PBC. Indeed, using quantitative structure activity relationship (QSAR) analysis on a peptide-xenobiotic conjugate microarray platform, we have demonstrated that when the lipoyl domain of PDC-E2 was modified with specific synthetic small molecule lipoyl mimics, the ensuing structures displayed highly specific reactivity to PBC sera, at levels often higher than the native PDC-E2 molecule. Hereby, we discuss our recent QSAR analysis data on specific AMA reactivity against a focused panel of lipoic acid mimic in which the lipoyl di-sulfide bond are modified. Furthermore, data on the immunological characterization of antigen and Ig isotype specificities against one such lipoic acid mimic; 6,8-bis(acetylthio)octanoic acid (SAc), when compared with rPDC-E2, strongly support a xenobiotic etiology in PBC. This observation is of particular significance in that approximately one third of patients who have taken excessive acetaminophen (APAP) developed AMA with same specificity as patients with PBC, suggesting that the lipoic domain are a target of APAP electrophilic metabolites such as NAPQI. We submit that in genetically susceptible hosts, electrophilic modification of lipoic acid in PDC-E2 by acetaminophen or similar drugs can facilitate loss of tolerance and lead to the development of PBC.

Natural history and management of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic inflammatory autoimmune disease that mainly targets the cholangiocytes of the interlobular bile ducts in the liver. It is a rare disease with prevalence of less than one in 2000. Its prevalence in developing countries is increasing presumably because of growth in recognition and knowledge of the disease. PBC is thought to result from a combination of multiple genetic factors and superimposed environmental triggers. The contribution of the genetic predisposition is evidenced by familial clustering. Several risk factors, including exposure to infectious agents and chemical xenobiotics, have been suggested. Common symptoms of the disease are fatigue and pruritus, but most patients are asymptomatic at first presentation. The prognosis of PBC has improved because of early diagnosis and use of ursodeoxycholic acid, the only established medical treatment for this disorder. When administered at adequate doses of 13–15 mg/kg/day, up to two out of three patients with PBC may have a normal life expectancy without additional therapeutic measures. However, some patients do not respond adequately to ursodeoxycholic acid and might need alternative therapeutic approaches.

Primary biliary cirrhosis and autoimmunity: molecules and mimics

There have been significant advances both in humans and experimental models that relate to the etiopathogenesis of primary biliary cirrhosis. Many of these advances are based on the rigorous definition of the antimitochondrial response, the serologic signature of PBC. First, it is well established that AMA are directed against members of the 2-oxoacid dehydrogenase complexes (2-OADC), among which the major epitopes are within the lipoylated domains of the E2 subunit of the pyruvate dehydrogenase complex (PDC-E2). Second, autoreactive CD4+ and CD8+ T cells can be detected in PBC peripheral blood, regardless of the AMA status, and the infiltration of autoreactive T cells in the liver and periductular spaces is one of the most prominent immune features. Autoreactive T cells of both subtypes recognize PDC-E2 sequences overlapping with the AMA epitopes. An increase in cytotoxic T cell precursors in the blood in the early stages of the disease compared to the advanced ones and a 10-fold increase of specific liver CD8+ T cells compared to peripheral blood have been demonstrated. Third, additional data on the immunobiology components of PBC autoimmunity has been recently obtained in CD4+CD25 high natural regulatory T cells which appear to be numerically reduced in PBC. PBC bile duct cells manifest unique features during apoptosis while co-culture experiments do not support a direct role for these cells in determining their immune –mediated injury. Apoptotic cells are phagocytosed by BECs and consequently are an exogenous source of autoantigens in cholangiocytes, possibly through anti-CD16. As a result, the impact of putative changes in apoptosis and autophagy specific to BEC remains to be fully determined in PBC. Fifth, the innate immune compartment has been recently investigated in PBC with promising results. PBC monocytes manifest an increased response to pathogen associated stimuli, as indicated by higher levels of pro-inflammatory cytokines. Further, the hyper-IgM associated with PBC is secondary to an aberrant innate immune response, potentially induced by stimulation of toll like receptor 9 by bacterial CpG-B. The female preponderance may hold an important key to PBC etiology. X-linked genes determine gender-related characteristics at different levels while also regulating the immune function, particulalry to maintain tolerance. Major X chromosome defects such as those leading to Turner’s syndrome or premature ovarian failure are commonly characterized by autoimmune comorbidities (particularly thyroid disease) and, less frequently, cholestasis. Our group first determined a significantly higher frequency of monosomy of the X chromosome in peripheral leukocytes (particularly those of the adaptive immune response, i.e. T and B cells) in women PBC compared to age-matched control women. Monosomy frequency correlated with age in all three groups, as expected but monosomic cells were not microchimeric cells. We further demonstrated that the X loss in PBC affected was not random but affected more frequently one parentally-inherited chromosome. Several key animal models of autoimmune cholangitis have now been described. First, a genomic variant of the non obese diabetic (NOD) mouse (NOD.c3c4) has been observed to manifest autoimmune cholestasis with AMA and ANA positivities in 50%–60% and 80%–90%, respectively. Liver histology demonstrated portal lymphocyte infiltration with chronic non-suppurative cholangitis and PBC-like granulomas. Second, a dominant negative form of trasforming growth factor β (TGFβ) receptor II (dnTGFβRII) mouse develop serum AMA in 100% of mice. The TGFβ receptor II regulates lymphocyte activation and the appearance of PBC in this model suggests a specific condition of T cells with impaired TGFβ signaling in the presence or absence of B cells is involved. Third, the knockout of interleukin 2 receptor α leads to a murine phenotype with 100% serum AMA positivity, 80% serum ANA positivity, and portal lymphocyte infiltration and vanishing bile ducts. This model is of particular interest based on the report of autoimmune cholangitis in a pediatric case of IL2Rα deficiency. Fourth, Ae2a,b also develop autoimmune phenomenon and a PBC-like disease. Finally, immunization of mice with chemical xenobiotics has also been shown to lead to a PBC-like disease. These data and observations will be put in the context of the key mechanisms, including the role of TLRs in modulating these responses.

Infectious Agents and Xenobiotics in the Etiology of Primary Biliary Cirrhosis

Primary biliary cirrhosis (PBC)is a chronic autoimmune cholestatic liver disease that manifests a latitudinal gradient in prevalence and incidence. The mechanisms leading to the initiation and perpetuation of PBC remain largely enigmatic, although it is established that a combination of genetic predisposition and environmental stimulation is required. PBC is also characterized by a high concordance rate in monozygotic twins and is considered a model autoimmune disease because of several features common to other conditions and the relatively homogeneous serological and biochemical features. From a diagnostic standpoint, PBC is characterized by the highest specificity of serum autoantibodies directed at mitochondrial proteins. Several risk factors have been suggested to be associated with PBC, including exposure to infectious agents and chemical xenobiotics that will be critically discussed in the present review article.

Environmental agents involved in the cause of primary biliary cirrhosis.

Primary biliary cirrhosis (PBC) is an immune mediated chronic cholestatic liver disease with a slowly progressive course It is a universal disease with a reported latitudinal gradient in prevalence and incidence. The aetiology of primary biliary cirrhosis is still unknown. It is characterized by a 60% concordance in monozygotic twins and is considered an autoimmune disease because of several features common to other autoimmune conditions and the relatively homogeneous serological and biochemical features. However geoepidemiological and clinical studies strongly imply that environmental factors also play an important role. It is accepted that the disease is clearly the result of a combination of genetic and environmental factors. Several risk factors have been suggested to be associated with PBC, including exposure to infectious agents and chemical xenobiotics. This review will attempt to place such factors in perspective.

Environmental Agents Involved in the Cause of Primary Biliary Cirrhosis

Primary biliary cirrhosis (PBC) is an immune mediated chronic cholestatic liver disease with a slowly progressive course It is a universal disease with a reported latitudinal gradient in prevalence and incidence. The aetiology of primary biliary cirrhosis is still unknown. It is characterized by a 60% concordance in monozygotic twins and is considered an autoimmune disease because of several features common to other autoimmune conditions and the relatively homogeneous serological and biochemical features. However geoepidemiological and clinical studies strongly imply that environmental factors also play an important role. It is accepted that the disease is clearly the result of a combination of genetic and environmental factors. Several risk factors have been suggested to be associated with PBC, including exposure to infectious agents and chemical xenobiotics. This review will attempt to place such factors in perspective.

Infectious agents and xenobiotics in the etiology of primary biliary cirrhosis.

Primary biliary cirrhosis (PBC)is a chronic autoimmune cholestatic liver disease that manifests a latitudinal gradient in prevalence and incidence. The mechanisms leading to the initiation and perpetuation of PBC remain largely enigmatic, although it is established that a combination of genetic predisposition and environmental stimulation is required. PBC is also characterized by a high concordance rate in monozygotic twins and is considered a model autoimmune disease because of several features common to other conditions and the relatively homogeneous serological and biochemical features. From a diagnostic standpoint, PBC is characterized by the highest specificity of serum autoantibodies directed at mitochondrial proteins. Several risk factors have been suggested to be associated with PBC, including exposure to infectious agents and chemical xenobiotics that will be critically discussed in the present review article.

Environmental causes of autoimmunity: Clues to the loss of tolerance in primary biliary cirrhosis (137.14)

Abstract Primary biliary cirrhosis (PBC) is a human autoimmune disease that destroys small bile ducts and is characterized by antimitochondrial antibodies (AMAs) directed to the inner lipoyl domain of pyruvate dehydrogenase (PDC-E2). Our thesis is that environmental factors trigger the onset of PBC by breaking tolerance to PDC-E2. In particular, we submit that chemical xenobiotic modification of the lipoyl moiety of PDC-E2 results in creation of a neoantigen with a subsequent immune response in genetically predisposed individuals. Our previous work has been focused in two areas: the use of microarrays to identify chemical xenobiotics that react to AMAs as well as or better than native autoantigen and, second, the demonstration that a PBC-like disease can be generated in mice following immunization with our optimal xenobiotic coupled to BSA. Herein, we have focused on fine mapping of the optimal chemical compounds that mimic lipoic acid. We modified the S-S linkage ring structure of lipoic acid and conjugated an array of such chemicals on a PDC-E2 peptide backbone and then analyzed such compounds for reactivity using sera from patients with PBC and a variety of controls. Importantly, by such chemical fine mapping, we now identify 6,8-bis(acetylthio)octanoic acid as an optimal chemical structure. Finally, we note that this compound has striking structural similarity with a variety of drug metabolites.

Loss of tolerance in C57BL/6 mice to the autoantigen E2 subunit of pyruvate dehydrogenase by a xenobiotic with ensuing biliary ductular disease†

There have been important advances in defining effector mechanisms for several human autoimmune diseases. However, for most human autoimmune diseases, the induction stage is less well defined and there are very few clues on etiology. Our laboratory has focused on defining the molecular basis of autoantibody recognition and epitope modification in primary biliary cirrhosis (PBC). Our work has demonstrated that antibodies to mitochondria, the hallmark of disease, are directed against a very conserved site of pyruvate dehydrogenase, the E2 subunit of pyruvate dehydrogenase (PDC-E2). We have also demonstrated that several chemical xenobiotics, chosen based on quantitative structural activity relationship analysis and rigorous epitope analysis, when coupled to the lysine residue that normally binds the lipoic acid cofactor of PDC-E2, reacts as well or better to PBC sera than native autoantigen. In the present studies, we immunized C57BL/6 mice with one such xenobiotic, 2-octynoic acid, coupled to bovine serum albumin and we followed the mice for 24 weeks. Animals were studied for appearance of histologic lesions as well as appearance of antibodies to PDC-E2, serum levels of tumor necrosis factor-alpha and interferon-gamma, and splenic and liver lymphoid phenotyping by flow cytometry. Mice immunized with 2-octynoic acid manifest autoimmune cholangitis, typical mitochondrial autoantibodies, increased liver lymphoid cell numbers, an increase in CD8(+) liver infiltrating cells, particularly CD8(+) T cells that coexpress CD44, and finally an elevation of serum tumor necrosis factor-alpha and interferon-gamma. these data provide a persuasive argument in favor of an environmental origin for human PBC.

Chemical Xenobiotics and Mitochondrial Autoantigens in Primary Biliary Cirrhosis: Identification of Antibodies against a Common Environmental, Cosmetic, and Food Additive, 2-Octynoic Acid

Emerging evidence has suggested environmental factors as causative agents in the pathogenesis of primary biliary cirrhosis (PBC). We have hypothesized that in PBC the lipoyl domain of the immunodominant E2 component of pyruvate dehydrogenase (PDC-E2) is replaced by a chemical xenobiotic mimic, which is sufficient to break self-tolerance. To address this hypothesis, based upon our quantitative structure-activity relationship data, a total of 107 potential xenobiotic mimics were coupled to the lysine residue of the immunodominant 15 amino acid peptide of the PDC-E2 inner lipoyl domain and spotted on microarray slides. Sera from patients with PBC (n = 47), primary sclerosing cholangitis (n = 15), and healthy volunteers (n = 20) were assayed for Ig reactivity. PBC sera were subsequently absorbed with native lipoylated PDC-E2 peptide or a xenobiotically modified PDC-E2 peptide, and the remaining reactivity analyzed. Of the 107 xenobiotics, 33 had a significantly higher IgG reactivity against PBC sera compared with control sera. In addition, 9 of those 33 compounds were more reactive than the native lipoylated peptide. Following absorption, 8 of the 9 compounds demonstrated cross-reactivity with lipoic acid. One compound, 2-octynoic acid, was unique in both its quantitative structure-activity relationship analysis and reactivity. PBC patient sera demonstrated high Ig reactivity against 2-octynoic acid-PDC-E2 peptide. Not only does 2-octynoic acid have the potential to modify PDC-E2 in vivo but importantly it was/is widely used in the environment including perfumes, lipstick, and many common food flavorings.

DNA integrity determination in marine invertebrates by Fast Micromethod ®

This study was focused toward the adaptation of the previously developed Fast Micromethod ® for DNA damage determination to marine invertebrates for the establishment of biomonitoring assessment. The Fast Micromethod ® detects DNA damage (strand breaks, alkali-labile sites and incomplete excision repair) and determines DNA integrity in cell suspensions or tissue homogenates in single microplates. The procedure is based on the ability of the specific fluorochrome dye PicoGreen ® to preferentially interact with high integrity DNA molecules, dsDNA, in the presence of ssDNA and proteins in high alkaline medium, thereby allowing direct fluorometric measurements of dsDNA denaturation without sample handling and stepwise DNA separations. The results presented herein describe the influence of the DNA amount and the pH of the denaturation media on slopes of the kinetic denaturation curves and calculated strand scission factors (SSFs). The optimal amount of DNA in Mytilus galloprovincialis gills homogenate was found to be 100 ng ml −1 and the greatest differences in DNA unwinding kinetics (slopes and SSF values) were reached at pH 11.5. The induction of DNA damage and loss of DNA integrity was measured in native DNA isolated from cotton-spinner Holothuria tubulosa, marine sponge Suberites domuncula cells and mussel M. galloprovincialis gills homogenate. DNA damage and loss of DNA integrity were detected after induction by different doses of (γ-rays, generated by 137 Cs 1800 Ci; 0–500 rad in marine sponge S. domuncula cells up to SSF×(−1) values 0.082±0.012 for the highest radiation dose). Analysis by chemical xenobiotics based on the in vitro action of bleomycin (bleomycin–Fe(II) complex 0–50 or 0–83 μg ml −1 (μM)) with native DNA from cotton-spinner H. tubulosa and mussel M. galloprovincialis gills homogenate yielded values of 0.537±0.072 and 0.130±0.018, respectively. In vivo experiments with mussel M. galloprovincialis gills homogenate by 4-nitroquinoline- N-oxide (NQO; 0–1 μg g −1 NQO mussel) and bezo[a]pyrene (B[a]P; 0–20 μg g −1 B[a]P mussel) indicated SSF×(−1) values of 0.121±0.016 and 0.090±0.007, respectively, for the highest applied doses of chemical xenobiotics. The analytical technique described here allows simple and fast analysis of DNA integrity, requires very short time for multiple analyses (less than 3 h) and even less than 100 ng DNA per single well (50 ng DNA isolated from cotton-spinner, 12,500 sponge cells or about 10 mg of mussel gills homogenate) in a microplate. This makes the Fast Micromethod ® applicable for the measurement of DNA integrity of small samples for genotoxicity assessment (biomonitoring), the effects of genotoxins on lower marine taxa or sessile invertebrates in marine environment (e.g. sponges, mussels) and the estimation of directional changes and harmful effects in the ecosystem.

Early onset of virus infection and up-regulation of cytokines in mice treated with cadmium and manganese.

A substantial database indicates that a large number of environmental pollutants, chemicals and therapeutic agents to which organisms are exposed cause immunotoxicity. The suppression of immune functions may cause increased susceptibility of the host to a variety of microbial pathogens potentially resulting in a life-threatening state. Evaluation of the immunotoxic potential of chemical xenobiotics is of great concern and, therefore, we have investigated the impact of exposure of inorganic metals, specifically cadmium (Cd) and manganese (Mn) on Encephalomyocarditis virus (EMCV), Semliki Forest virus (SFV), and Venezuelan Equine Encephalitis virus (VEEV) infection. Pretreatment with a single, oral dose of Cd or Mn increased the susceptibility of mice to a sub-lethal infection of these viruses as observed by increased severity of symptoms and mortality compared to untreated controls. An early onset of virus infection was found in brains of Cd and Mn treated animals. Histopathological observations of the brain indicate evidence of inflammation and greater tissue pathology in Cd-or Mn-exposed mice compared to control animals. Meningitis and vascular congestion was seen in virus infected mice in all the metal treated groups, and further, the perivascular inflammation appeared earlier in treated mice compared to control. Encephalitis was maximum in Cd pretreated mice. Widespread environmental contamination of metals and the potential for their exposure and subsequent infection of humans or animals is indicative that further studies of these and all other metals are important to understand the effect of environmental pollution on human health.