Search results for "Chironomus"
showing 10 items of 33 documents
Toxicity of fullerene (C60) to sediment-dwelling invertebrate Chironomus riparius larvae
2011
An environmentally realistic method to test fullerene (C(60) ) toxicity to the benthic organism Chironomus riparius was created by allowing suspended fullerenes to settle down, making a layer on top of the sediment. To test the hypothesis that higher food concentrations will reduce toxic responses, two food concentrations were tested (0.5 and 0.8% Urtica sp.) in sediment containing fullerene masses of 0.36 to 0.55 mg/cm(2) using a 10-d chronic test. In the 0.5% food level treatments, there were significant differences in all growth-related endpoints compared with controls. Fewer effects were observed for the higher food treatment. Fullerene agglomerates were observed by electron microscopy …
Detecting Cd adaptation footprint in C. riparius with a multi-genomic approach
2021
AbstractEvolutionary processes and acquired tolerance to toxicants are important factors governing how animals respond to chemical exposure. Evidence for increased tolerance to cadmium (Cd), a widely distributed toxic metal in aquatic environments, in Chironomus riparius is conflicting and still questioned if it happens through phenotypic plasticity or genetic adaptation. The present study considered the relevance of directional environmental changes by increasing contaminant concentration in a multigenerational selection experiment. Evaluation of measurable life-cycle traits, transcriptomic responses and quantitative genetics from an evolve and resequencing (E&R) experiment were integr…
Establishing Laboratory Cultures and Performing Ecological and Evolutionary Experiments with the Emerging Model Species <em>Chironomus Riparius…
2018
Chironomus riparius is a well-established model organism in various fields such as ecotoxicology and ecology, and therefore environmental preferences, ecological interactions and metabolic traits are well-studied. With the recent publication of a high-quality draft genome, as well as different population genetic parameters such as mutation and recombination rate, the species can be used as an alternative to the Drosophila models in experimental population genomics or molecular ecology. To facilitate access to this promising experimental model species for a wider range of researchers, we describe experimental methods to first create and sustain long term cultures of C. riparius and then use …
Chironomus riparius exposure to fullerene-contaminated sediment results in oxidative stress and may impact life cycle parameters
2015
A key component of understanding the potential environmental risks of fullerenes (C60) is their potential effects on benthic invertebrates. Using the sediment dwelling invertebrate Chironomus riparius we explored the effects of acute (12 h and 24 h) and chronic (10 d, 15 d, and 28 d) exposures of sediment associated fullerenes. The aims of this study were to assess the impact of exposure to C60 in the sediment top layer ((0.025, 0.18 and 0.48) C60 mg/cm2) on larval growth, oxidative stress and emergence rates and to quantify larval body burdens in similarly exposed organisms. Oxidative stress localization was observed in the tissues next to the microvilli and exoskeleton through a method fo…
A variable intron distribution in globin genes of Chironomus: evidence for recent intron gain
1998
The intron positions found in globin genes of plants, protozoa and invertebrates have been interpreted as evidence for a three-intron-four-exon structure of the ancestral globin gene. In particular, the so-called 'central' introns, which are not found in vertebrate globin genes but are present in a variety of invertebrate and plant species, have been used as an argument for an ancestral gene structure featuring three introns. We have analyzed the presence or absence of central introns in the Gb genes 2beta, 9 and 7A of various European and Australasian species of the insect Chironomus. We find unrelated central introns at different positions in some of the species investigated, while other …
Genome instability ofChironomus ripariusMg. andChironomus pigerStrenzke (Diptera, Chironomidae)
2007
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 popula…
Subrepeats result from regional DNA sequence conservation in tandem repeats in Chironomus telomeres
1990
Repeat units, widespread in eukaryotic genomes, are often partially or entirely built up of subrepeats. Homogenization between whole repeat units arranged in tandem usually can best be understood as a result of unequal crossing over. Such a mechanism is less plausible for maintaining similarities between subrepeats within a repeat unit when present in a regular array. In Chironomus telomeres, large blocks of tandemly repeated approximately 350 base-pair units contain two or three pairs of subrepeats with high mutual identities, embedded in linker DNA, non-repetitive within the repeat unit. Measurements of evolutionary base changes in two closely related species, Chironomus tentans and Chiro…
The Primary Structure of Several Hemoglobin Genes from the Genome of Chironomus tentans
1991
In addition to Chironomus thummi thummi, Chironomus tentans is another Chironomid species in which the Hb proteins have been investigated (1) and in which the Hb genes have been localized (2). Thus, this species is an ideal candidate for the study of Hb gene structure and evolution.
In situlocalization of the evolutionary conserved Cpy/Cty gene in the subfamily Chironominae (Chironomidae, Diptera): establishment of chromosomal ho…
2009
The homologous sites on the salivary gland chromosomes of 13 species from three genera: Chironomus, Glyptotendipes, Kiefferulus have been mapped by means of fluorescent in situ hybridization using the evolutionary conserved gene Cpy⁄Cty (clone Cla1.1). In all species of genus Chironomus and genus Kiefferulus, the Cty⁄Cpy gene is located on arm F of chromosome EF. The relocation of the gene among the species of genus Chironomus can be done by simple or complex homozygous inversions which occurred during the divergent evolution of the chromosome of the species. In the genus Glyptotendipes, the Cty⁄Cpy gene was localized in arm E of chromosome EF. Since the banding patterns of salivary gland c…
Ecotoxicity of sediments in rivers: Invertebrate community, toxicity bioassays and the toxic unit approach as complementary assessment tools
2015
The determination of the real toxicity of sediments in aquatic ecosystems is challenging and necessary for an appropriate risk assessment. Different approaches have been developed and applied over the last several decades. Currently, the joint implementation of chemical, ecological and toxicological tools is recommended for an appropriate and successful toxicity risk assessment. We chose the combination of the toxic unit approach with acute pore water tests (Vibrio fischeri, Pseudokirchneriella subcapitata and Daphnia magna) and whole-sediment exposure tests (V. fischeri, Chironomus riparius), together with invertebrate community composition (multivariate analyses) to detect short and long-…