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Jinhee Choi - One of the best experts on this subject based on the ideXlab platform.
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effect of cadmium exposure on the globin protein expression in 4th instar larvae of Chironomus riparius mg diptera chironomidae an ecotoxicoproteomics approach
Proteomics, 2009Co-Authors: Jinhee Choi, Mihee HaAbstract:In order to identify Chironomus hemoglobin (Hb) as a biomarker of ecotoxicity monitoring; herein, the effects of cadmium chloride (Cd) on Hb parameters were investigated in the 4th instar larvae of Chironomus riparius. The expressions of globin mRNA and hemolymph protein, using ecotoxicoproteomic approach, were investigated. Conventional ecotoxicity tests were also conducted to validate the ecotoxicological relevance of the response of Chironomus Hb as a biomarker. The proteomic analysis indicated that exposure to Cd lead alteration in the expression of hemolymph protein, with the total expressions of 12 hemolymph protein spots decreasing in response to treatment, with that of two increasing in response to Cd exposure. In addition, all of the spots differentially expressed in response to Cd treatment were identified as globin proteins. The decreased total Hb content observed in the hemolymph of larvae exposed to Cd suggested that the decreased expression of selected globin proteins in response to Cd exposure impacted on Hb synthesis. The overall results suggested that Hb could be a target molecule for exposure to Cd in C. riparius, with a proteomic approach appearing to be an ideal tool for the discovery of biomarkers in ecotoxicological research.
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chemical induced alteration of hemoglobin expression in the 4th instar larvae of Chironomus tentans mg diptera chironomidae
Environmental Toxicology and Pharmacology, 2008Co-Authors: Jinhee ChoiAbstract:In this study, a preliminary characterization of the multiplicity of Chironomus hemoglobin (Hb) was conducted on the larvae of Chironomus tentans Mg. (Diptera: Chironomidae) by the molecular mass and isoelectric point. In order to identify Chironomus Hb as potential biomarker of environmental contamination, alteration of individual Hb by exposure to environmental chemicals, namely, nonylphenol, benzo[a]pyrene, chloropyriphos and cadmium chloride, were evaluated. To validate the ecotoxicological relevance of Chironomus Hb as a potential biomarker, ecotoxicity test using growth rate as toxic endpoint was also conducted. This study revealed a striking heterogeneity in C. tentans Hb; 10 Hb isoforms were observed in the larvae of 4th instar C. tentans by their molecular mass and by their isoelectric point. Chemical-induced alteration of individual Hb expression suggests that C. tentans Hb can be a target molecule for chemical exposure. Overall results suggest that the expression pattern of Hb proteins may potentially contribute to the development of a biomarker for ecotoxicity monitoring in C. tentans.
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effects of environmental contaminants on hemoglobin of larvae of aquatic midge Chironomus riparius diptera chironomidae a potential biomarker for ecotoxicity monitoring
Chemosphere, 2008Co-Authors: Mihee Ha, Jinhee ChoiAbstract:The effects of environmental contaminants (i.e., nonylphenol, bisphenol A diglycidyl ether, benzo[a]pyrene, chlorpyriphos, paraquat dichloride, and lead nitrate) on Chironomus hemoglobin were investigated in the 4th instar larvae of Chironomus riparius (Diptera: Chironomidae), with respect to the total hemoglobin contents, individual globin gene expression, individual globin protein expression and hemoglobin oxidation. In our studies, 7 and 6 globin isoforms were preliminarily characterized by molecular weight and isoelectric point, respectively, in the 4th instar larvae of C. riparius. Most chemicals were unable to modify the total hemoglobin contents, however, the expression patterns of the globin transcript and proteins suggest that C. riparius globin exists in both inducible and consecutively expressed forms, with multiplicity that may allow this animal to better adapt toward stressful environmental conditions, including pollution stress. The oxyhemoglobin was observed to be downregulated in C. riparius on exposure to bisphenol A and chlorpyriphos, probably reflecting its increased autoxidation to methemoglobin. The overall results would suggest that globin can be a target molecule of environmental contaminants, and of the tested parameters, the alteration of individual globin levels (i.e., mRNA or protein levels) may have potential for the development of a biomarker for ecotoxicity monitoring.
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expression of heat shock protein and hemoglobin genes in Chironomus tentans diptera chironomidae larvae exposed to various environmental pollutants a potential biomarker of freshwater monitoring
Chemosphere, 2006Co-Authors: Chulhwi Park, Jinhee ChoiAbstract:To identify a sensitive biomarker of freshwater monitoring, we evaluated pollutant-induced expression of heat shock proteins (HSPs) and hemoglobins (Hbs) genes in the larvae of the aquatic midge Chironomus tentans (Diptera, Chironomidae). As pollutants, we examined nonylphenol, bisphenol-A, 17α-ethynyl estradiol, bis(2-ethylhexyl) phthalate, endosulfan, paraquat dichloride, chloropyriphos, fenitrothion, cadmium chloride, lead nitrate, potassium dichromate, benzo[a]pyrene and carbon tetrachloride. We also investigated larval growth as a physiological descriptor by measuring changes in the body fresh weight and dry weight after chemical exposure. The response of the HSPs gene expression by chemical exposure was rapid and sensitive to low chemical concentrations but it was not stressor specific. Interestingly, an increase in the expression of HSPs genes was observed not only in a stress inducible form (HSP70), but also in a constitutively (HSC70) expressed form. The expression of Hb genes showed chemical-specific responses: that is, alkyl phenolic compounds increased the expression of hemoglobin genes, whereas pesticides decreased the expression. As expected, molecular-level markers were more sensitive than physiological endpoints, suggesting that gene expression could be developed as an early warning biomarker in this animal. The overall results suggest that the expression of HSP and Hb genes in Chironomus could give useful information for diagnosing general health conditions in fresh water ecosystem. The expression of Hb genes, in particular, seems to be a promising biomarker, especially in view of the potential of Chironomus larvae as a biomonitoring species and of the physiological particularities of their respiratory pigments.
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effect of potassium dichromate and fenitrothion on hemoglobins of Chironomus riparius mg diptera chironomidae larvae potential biomarker of environmental monitoring
Environmental Monitoring and Assessment, 2004Co-Authors: Jinhee Choi, Hélène RocheAbstract:In an attempt to identify Chironomus hemoglobins as biomarkers for environmental monitoring, alterations in the hemoglobins in Chironomus riparius Mg. (Diptera: Chironomidae) larvae, exposed to potassium dichromate and fenitrothion, were investigated under laboratory conditions. The hemoglobins were evaluated in terms of their total contents by a cyanomethemoglobin procedure, individual components by electrophoresis of isoelectric focusing, and their oxidation by multi wavelength rapid-scanning spectrophotometry. The total hemoglobin contents increased at the high level of fenitrothion exposure. No variations in the individual hemoglobin component levels were found, by exposure to either fenitrothion or potassium dichromate. Whereas, the absorption spectra of the hemoglobinsshowed decreases in the peaks corresponding to the oxyhemoglobins by exposure to both compounds, but more sensitively by the chromium, which probably reflects the increase of the autoxidation of the oxyhemoglobins to methemoglobins by these compounds. These results suggest that autoxidation of the hemoglobins in Chironomus riparius seems to be a sensitive parameter in response to redox-active chemicalexposure, and this biochemical parameter could be developed as a biomarkerin environmental monitoring.
Mihee Ha - One of the best experts on this subject based on the ideXlab platform.
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effect of cadmium exposure on the globin protein expression in 4th instar larvae of Chironomus riparius mg diptera chironomidae an ecotoxicoproteomics approach
Proteomics, 2009Co-Authors: Jinhee Choi, Mihee HaAbstract:In order to identify Chironomus hemoglobin (Hb) as a biomarker of ecotoxicity monitoring; herein, the effects of cadmium chloride (Cd) on Hb parameters were investigated in the 4th instar larvae of Chironomus riparius. The expressions of globin mRNA and hemolymph protein, using ecotoxicoproteomic approach, were investigated. Conventional ecotoxicity tests were also conducted to validate the ecotoxicological relevance of the response of Chironomus Hb as a biomarker. The proteomic analysis indicated that exposure to Cd lead alteration in the expression of hemolymph protein, with the total expressions of 12 hemolymph protein spots decreasing in response to treatment, with that of two increasing in response to Cd exposure. In addition, all of the spots differentially expressed in response to Cd treatment were identified as globin proteins. The decreased total Hb content observed in the hemolymph of larvae exposed to Cd suggested that the decreased expression of selected globin proteins in response to Cd exposure impacted on Hb synthesis. The overall results suggested that Hb could be a target molecule for exposure to Cd in C. riparius, with a proteomic approach appearing to be an ideal tool for the discovery of biomarkers in ecotoxicological research.
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effects of environmental contaminants on hemoglobin of larvae of aquatic midge Chironomus riparius diptera chironomidae a potential biomarker for ecotoxicity monitoring
Chemosphere, 2008Co-Authors: Mihee Ha, Jinhee ChoiAbstract:The effects of environmental contaminants (i.e., nonylphenol, bisphenol A diglycidyl ether, benzo[a]pyrene, chlorpyriphos, paraquat dichloride, and lead nitrate) on Chironomus hemoglobin were investigated in the 4th instar larvae of Chironomus riparius (Diptera: Chironomidae), with respect to the total hemoglobin contents, individual globin gene expression, individual globin protein expression and hemoglobin oxidation. In our studies, 7 and 6 globin isoforms were preliminarily characterized by molecular weight and isoelectric point, respectively, in the 4th instar larvae of C. riparius. Most chemicals were unable to modify the total hemoglobin contents, however, the expression patterns of the globin transcript and proteins suggest that C. riparius globin exists in both inducible and consecutively expressed forms, with multiplicity that may allow this animal to better adapt toward stressful environmental conditions, including pollution stress. The oxyhemoglobin was observed to be downregulated in C. riparius on exposure to bisphenol A and chlorpyriphos, probably reflecting its increased autoxidation to methemoglobin. The overall results would suggest that globin can be a target molecule of environmental contaminants, and of the tested parameters, the alteration of individual globin levels (i.e., mRNA or protein levels) may have potential for the development of a biomarker for ecotoxicity monitoring.
Thomas Hankeln - One of the best experts on this subject based on the ideXlab platform.
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genome instability of Chironomus riparius mg and Chironomus piger strenzke diptera chironomidae
Caryologia, 2007Co-Authors: Thomas Hankeln, Erwin R. Schmidt, P Michailova, G Sella, Keith N WhiteAbstract:Intra and interspecific variation was evaluated in two Bulgarian populations (Pancharevo and Koka- lijane) of the two sibling and homosequential species Chironomus riparius Mg. and Chironomus piger Strenzke, by analyzing structural and functional alterations in salivary gland polytene chromosomes. In both species genome in- stability was demonstrated, which was expressed by structural and functional somatic chromosomal alterations. In the C. riparius population from Pancharevo, living in sediments containing high concentrations of Cu, Pb and Zn, salivary gland cells containing somatic rearrangements appeared at a significantly higher frequency (51.92%) than in the Kokalijane C. piger population, living in heavy metal-unpolluted sediments (21.3%). In the C. riparius popu- lation, somatic aberrations were distributed at different points along the chromosomes while in the C. piger popula- tion, somatic rearrangements were concentrated in the pericentromeric regions of chromosomes CD, EF and in proximal part of arms D and F. At the cytological level using FISH analysis, both species can be identified also by the different location of tandem-repetitive minisatellite DNA clusters of Alu and Hinf families, and insertion sites of the LINE retrotransposon NLRCTh1. While location of the former is fixed, NLRCth1 appeared to have both fixed and inter-individually variable positions in both species. On average, 19.0 ± 9.5 insertions of NLRCth1 per individ- ual were observed in C. riparius and 5.57 ± 2.09 in C. piger. In both species locations of minisatellite DNA clusters, NLRCth1 retrotransposons and aberration breakpoints concentrated in proximal regions of chromosomes, and the majority of the breakpoints were located in sections containing blocks of repetitive DNA clusters.
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development and localization of microsatellite markers for the sibling species Chironomus riparius and Chironomus piger diptera chironomidae
Molecular Ecology Notes, 2006Co-Authors: Carsten Nowak, Erwin R. Schmidt, Thomas Hankeln, Klaus SchwenkAbstract:Five variable microsatellite loci are reported for the nonbiting midge species Chironomus riparius and Chironomus piger. All loci show considerable intraspecific variation and species-specific alleles, which allow to discriminate among the two closely related species and their interspecific hybrids, and to estimate genetic diversity within and between populations. Additionally, the loci were localized on C. riparius polytene chromosomes to verify their single copy status and investigate possible chromosomal linkage. The described markers are used in different studies with regard to population and ecological genetics and evolutionary ecotoxicology of Chironomus.
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transposition of minisatellite like dna in Chironomus midges
Genome, 1994Co-Authors: Thomas Hankeln, Angela Rohwedder, Bettina Weich, Erwin R. SchmidtAbstract:Cla elements are a family of tandem repetitive DNA sequences present in the genome of several Chironomus species. Interspersed clusters of Cla elements are widely distributed all over the chromosomes in C. thummi thummi, while they seem to be limited to the centromeric regions in the closely related subspecies C. t. piger. Here we present molecular evidence that this differential distribution is due to a transposition of Cla elements during evolution of the C. t. thummi genome. We have cloned a "filled" integration site (containing a Cla element cluster) from C. t. thummi and the corresponding "empty" genomic site from C. t. piger and other related species. The comparison shows that tandem repetitive elements may be mobilized together with flanking DNA.Key words: minisatellites, transposition, Chironomus.
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The organization, localization and nucleotide sequence of the histone genes of the midge Chironomus thummi.
Chromosoma, 1991Co-Authors: Thomas Hankeln, Erwin R. SchmidtAbstract:Several histone gene repeating units containing the genes for histones H1, H2A, H2B, H3 and H4 were isolated by screening a genomic DNA library from the midge Chironomus thummi ssp. thummi. The nucleotide sequence of one complete histone gene repeating unit was determined. This repeating unit contains one copy of each of the five histone genes in the order and orientation 〈H3 H4〉 〈H2A H2B〉 H1〉. The overall length is 6262 bp. The orientation, nucleotide sequence and inferred amino acid sequence as well as the chromosomal arrangement and localization are different from those reported for Drosophila melanogaster. The codon usage also shows marked differences between Chironomus and Drosophila. Thus the histone gene structure reported for Drosophila is not typical of all insects.
J L Diez - One of the best experts on this subject based on the ideXlab platform.
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telomeres in Chironomus thummi are characterized by different subfamilies of complex dna repeats
Chromosoma, 2001Co-Authors: J L Martinez, Jan Edstrom, Gloria Morcillo, J L DiezAbstract:Members of the genus Chironomus, as well as other Diptera, lack the highly conserved structure of most telomeres, characterized by short repeats generated by telomerase, and have long repeats at their chromosome ends. Among Chironomus species with characterized telomeres Chironomus thummi is of particular interest because one of the telomeres, 3R, forms a giant puff in response to heat shock and other stress treatments. The puff contains nucleoprotein granules in which transcripts of the telomeric repeats are present. Most other nontelocentric telomeres irregularly form less pronounced heat shock puffs. One, the 4R telomere is, however, exceptional in being completely refractory to heat shock. We now pose the question whether the repeats in 3R and 4R have special sequence features. We find three different subfamilies of telomeric repeats in C. thummi, named TsA, TsB and TsC. They have an identical length (176 bp) and display base differences in defined regions, V1 and V2, connected by conserved segments. The TsA subfamily is localized exclusively at 3R, TsC only at 4R, whereas TsB repeats are shared by the remaining nontelocentric telomeres: 1R, 1L, 2R, 2L and 3L. Consequently both 3R and 4R have unique types of telomeric repeats. The 176 bp type repeats are absent from the telocentric, left end of chromosome 4. These results allowed us to differentiate in polytene chromosomes four types of telomeres characterized by tandemly repeated specific sequences.
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hsp90 associates with specific heat shock puffs hsr omega in polytene chromosomes of drosophila and Chironomus
Chromosoma, 1993Co-Authors: G Morcillo, J L Diez, M E Carbajal, Robert M TanguayAbstract:The heat shock protein HSP90, which is mainly cytoplasmic, has recently been reported to be present in the nucleus. We have found a specific chromosomal localization of HSP90 in different species of Drosophila and Chironomus using immunocytochemical techniques with different mono- and polyclonal antibodies for this hsp. HSP90 was found associated with heat shock-induced puffs at 93D and 48B in salivary gland chromosomes of Drosophila melanogaster and Drosophila hydei, respectively. The localization of HSP90 to locus 93D occurred rapidly after the onset of heat shock and disappeared during recovery, concomitant with puff regression. The association of HSP90 with the 93D locus was strictly heat shock dependent as shown by the absence of HSP90 in puff 93D induced by either benzamide or colchicine. No specific nuclear staining was observed in unstressed control cells. HSP90 was also found in the temperature-induced telomeric Balbiani ring puffs (T-BRs) in Chironomus thummi and in one heat shock puff at I-1C in Chironomus tentans. Other heat shock puffs also appeared lightly stained with the HSP90 polyclonal antibody in both species of Chironomus. HSP90 was absent from the T-BRs when RNA synthesis was inhibited with Actinomycin D suggesting that the localization of HSP90 is dependent on transcription. Inhibition of protein synthesis did not prevent association of this hsp with the T-BRs, indicating that pre-existing HSP90 can associate with this locus. HSP90 did not associate with any telomeric chromosomal regions of unstressed cells. The present observations suggest that heat shock gene products such as HSP90 may somehow be involved in the regulation at the chromosomal level of other members of the heat shock gene family. Puffs 93D (D. melanogaster) and 48B (D. hydei) are equivalent and correspond to homologous gene loci (hsrω) that have unusual features that distinguish them from other heat shock puffs. The binding of HSP90 at T-BRs and at puff I-1C in the genus Chironomus is the first demonstration, albeit indirect, of the existence of hsrω analogous loci in species other than Drosophila.
Hélène Roche - One of the best experts on this subject based on the ideXlab platform.
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effect of potassium dichromate and fenitrothion on hemoglobins of Chironomus riparius mg diptera chironomidae larvae potential biomarker of environmental monitoring
Environmental Monitoring and Assessment, 2004Co-Authors: Jinhee Choi, Hélène RocheAbstract:In an attempt to identify Chironomus hemoglobins as biomarkers for environmental monitoring, alterations in the hemoglobins in Chironomus riparius Mg. (Diptera: Chironomidae) larvae, exposed to potassium dichromate and fenitrothion, were investigated under laboratory conditions. The hemoglobins were evaluated in terms of their total contents by a cyanomethemoglobin procedure, individual components by electrophoresis of isoelectric focusing, and their oxidation by multi wavelength rapid-scanning spectrophotometry. The total hemoglobin contents increased at the high level of fenitrothion exposure. No variations in the individual hemoglobin component levels were found, by exposure to either fenitrothion or potassium dichromate. Whereas, the absorption spectra of the hemoglobinsshowed decreases in the peaks corresponding to the oxyhemoglobins by exposure to both compounds, but more sensitively by the chromium, which probably reflects the increase of the autoxidation of the oxyhemoglobins to methemoglobins by these compounds. These results suggest that autoxidation of the hemoglobins in Chironomus riparius seems to be a sensitive parameter in response to redox-active chemicalexposure, and this biochemical parameter could be developed as a biomarkerin environmental monitoring.
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Hypoxia, hyperoxia and exposure to potassium dichromate or fenitrothion alter the energy metabolism in Chironomus riparius Mg. (Diptera: Chironomidae) larvae.
Comparative Biochemistry and Physiology C-toxicology & Pharmacology, 2001Co-Authors: Jinhee Choi, Hélène Roche, Thierry CaquetAbstract:Abstract Short-term (24 h) effects of four stressors (hypoxia, hyperoxia, potassium dichromate, fenitrothion) on the activity of the electron transport system (ETS) and total lipid, glycogen and protein contents were assessed in 4th instar larvae of Chironomus riparius. Hypoxia and hyperoxia caused an increase in ETS activity and protein content. Glycogen content decreased when larvae were placed under hypoxic conditions. ETS activity increased following exposure to 2 μg l−1 of fenitrothion. It decreased in larvae exposed to 20 μg l−1 of this insecticide. A decrease in lipid and glycogen contents was observed in larvae exposed to potassium dichromate or fenitrothion. Changes in ETS activity and lipid and glycogen contents may be related to the activation of the respiratory chain due to an increase in energy cost associated with homeostatic phenomena, such as detoxification processes. These results suggest that some parameters related to energy metabolism, such as ETS activity and lipid and glycogen contents, may be used as biomarkers of environmental disturbance in Chironomus riparius larvae.