Acute toxicity tests for the pesticides endosulfan and malathion on the larvae of Chironomus ramosus were conducted. Median Lethal Concentration (LC50) values of endosulfan were 0.55 x 10(-2), 0.16 x 10(-2), 0.089 x 10(-2) and 0.036 x 10(-2) ppb respectively, while those for malathion were 0.139 x 10(-2), 0.054 x 10(-2), 0.019 x 10(-2) and 0.0032 x 10(-2) ppb respectively, at 24, 48, 72 and 96 ...

Short mobile elements are present in different recombined forms as interspersed GC-rich islands between AT rich centromeric 155 bp tandem repeats in the dipteran Chironomus pallidivittatus . The basic element is 80 bp long, has a pronounced invert repeat structure and contains a 17 bp segment similar to the CENP-B box in mammals. The element inserts into a specific site of the 155 bp repeat in ...

The ecdysone titer of larvae and pupae of Chironomus thummi was determined by radioimmune assay (RIA) and revealed a concentration of about 150 ng/g fresh weigth in late third instar larvae and a peak of more than 450 ng/g fresh weight just preceding pupation. The ecdysone titer curve shows a high degree of correlation with previously observed puffing activity at the ecdysone sensitive chromoso...

The phylogenetic relationships and karyotype differentiation of 14 sibling species of Chironomus plumosus group were studied using comparative analysis of polytene chromosome banding sequences. Revision of banding sequence pools has been made for all species. Main and alternative banding sequences of 6 chromosomal arms (A, B, C, D, E, and F) of each species were used for the analysis. In total ...

Crustacean calcium bodies are epithelial sacs which contain a mineralized matrix. The objectives of this study were to describe the microscopic anatomy of calcium bodies in the terrestrial isopod Hyloniscus riparius and to establish whether they undergo molt-related structural changes. We performed 3D reconstruction of the calcium bodies from paraffin sections and analyzed their structure with ...

In most freshwater ecosystems, aquatic insects are dominant in terms of diversity; however, there is a disproportionately low number of records of alien species when compared to other freshwater organisms. The Chironomidae is one aquatic insect family that includes some examples of alien species around the world. During a study on aquatic insects in Amazonas state (Brazil), we collected specime...

Flow cytometric 1-parameter DNA analysis and 2-parameter DNA/protein analysis have been performed with cell material of the diptera species Chironomus thummi, Drosophila melanogaster, Calliphora vicina and Musca domestica using an impulse cytophotometer with a new quartz objective, that was especially manufactured for cytofluorometric investigations. The occurrence of heterogenous cell populati...

Embryos of Chironomus samoensis are programmed, by anterior u.v. irradiation, to form the abnormal body pattern 'double abdomen'. Most double abdomen embryos show a mirror-image duplication of abdominal segments in the absence of cephalic or thoracic segments. Such embryos can be 'rescued', i.e. restored to normal development, by microinjection of cytoplasm or RNA from unirradiated donor embryo...