Regulation of RNA polymerase II (RNAPII) during transcription is essential for controlling gene expression. Here we report that the transcriptional activity of RNAPII at the Balbiani ring 2.1 gene could be halted during stable elongation in salivary gland cells of Chironomus tentans larvae for extended time periods in a regulated manner. The transcription halt was triggered by heat shock and af...

Threshold concentrations for treatment related effects of 31 insecticides, as derived from aquatic micro-/mesocosm tests, were used to calibrate the predictive value of the European Tier-1 acute effect assessment on basis of laboratory toxicity tests with Daphnia magna, Chironomus spp., Americamysis bahia and Gammarus pulex. The acute Tier-1 effect assessment on basis of Daphnia (EC(50)/100) ov...

(With One Text-figure) Tendipes (= Chironomus) plumosus larvae are unique among species of Tendipes in employing a filter-feeding mechanism for obtaining their food (Walshe, 1947 a). The larva spins a sheet of salivary secretion across the lumen of its tube, after which, by rapid anteroposterior undulations of the body, it irrigates the tube. Plankton or other organic particles in the incoming ...

Divisispiculimermis mirus n. gen., n. sp., a mermithid parasitizing larvae of Chironomus sp. in the Cajón o Grande Stream, Córdoba, Argentina, is described. The new genus differs from all other mermithid genera in having paired spicules which are separated and divided into proximal and distal sectors. The other diagnostic characters of the genus are medium size, nematodes with the cuticle appea...

Single molecule observation in cells and tissue allows the analysis of physiological processes with molecular detail, but it still represents a major methodological challenge. Here we introduce a microscopic technique that combines light sheet optical sectioning microscopy and ultra sensitive high-speed imaging. By this approach it is possible to observe single fluorescent biomolecules in solut...

The distribution and speciation of arsenic (As) were analyzed in individuals of various life stages of a midge, Chironomus riparius, and the mosquito Culex tarsalis exposed to 1000 μg/l arsenate. X-ray absorption spectroscopy (XAS) revealed that C. riparius larvae accumulate As in their midgut, with inorganic arsenate [As(V)] being the predominant form, followed by arsenite [As(III)] and an As-...

Mercury bioavailability was assessed by exposing the dipteran Chironomus riparius for whole life cycle to legacy-contaminated fluvial sediments (0.038–0.285 mg Hg kg−1 d.w.) and analyzing tissue concentrations in larvae at different exposure times (7, 11, 16 days) adults. In same experiment, diffusive gradients thin-film passive samplers (DGTs), both piston- probe-shaped, were co-deployed retri...

Given the chemical properties of synthetic pyrethroids, it is probable that compounds, including esfenvalerate, that enter surface waters may become incorporated into aquatic insect food sources. We examined the effect of dietary esfenvalerate uptake in aquatic insects representing different functional feeding groups. We used three field-collected aquatic insect species: A grazing scraper, Ciny...

Abstract In nature, organisms face multiple abiotic stress concurrently. Our previous study has indicated how threshold level of lethality depends on the type and combination stressors. Many mechanisms exist by which respond to stressors maintain homeostasis. We examined homeostatic pliability in an extremophilic oriental midge Chironomus ramosus larvae under various combinatorial conditions de...