The fine structure and cytochemistry of the extremely large RNA puffs, or Balbiani rings, in salivary gland nuclei of midge, Chironomus thummi, larvae have been investigated. The Balbiani rings are composed of a diffuse mass of electron-opaque 400 to 500 A granules, short threads about 180 to 220 A in diameter and associated fine chromatin fibrils. These components appear to be organized into b...

In recent years, adult Chironomidae (particularly Chironomus yoshimatsui and Tokunagayusurika akamushi) emerging from polluted natural and man-made aquatic habitats in urban areas of Japan have become intolerable because they pose severe nuisance and economic problems. Several organophosphorus (OP) insecticides and insect growth regulators (IGRs) including methoprene and diflubenzuron were test...

Di(2-ethylhexyl) phthalate (DEHP) is a ubiquitous environmental pollutant used worldwide as a plasticizer and solvent in many formulations. Based on available toxicological data, it has been classified as toxic for reproduction and as an endocrine disruptor. Despite this, ecotoxicological studies in aquatic wildlife organisms are still scarce. In the present work, the toxic molecular alteration...

The composition and distribution of the benthic macroinvertebrate community in a lagoon fish-pond system in the Bay of Cadiz. Spain, were studied by taking monthly samples at 4 sites during 1991. A total of 29 macroinvertebrate species, representing 16 orders. were identified. Gastropods, amphipods and chironomid larvae dominated the macrofauna in term of numbers of individuals, while in biomas...

The secretory proteins of Chironomus tentans larvae, which are used to construct underwater feeding and pupation tubes, assemble into complexes in vitro. Members of a family of 1000 kDa proteins, the spIs, appear to form the fibrous backbone of the assembled complexes. The spIs consist of a core of tandemly repeating units of 60 to 90 amino acids that can be subdivided into two regions: the sub...

Polydimethylsiloxane (PDMS) is widely used in a number of industrial processes and consumer products that result in down-the-drain disposal. The log p value for the PDMS used in the present study was 10, and the vapor pressure and water solubility values were below detection limits. These physicochemical characteristics and a measured degradation rate of 3% after six months in moist soils sugge...

In contrast to bird flocks, fish schools and animal herds, midge swarms maintain cohesion but do not possess global order. High-speed imaging techniques are now revealing that these swarms have surprising properties. Here, I show that simple models found on the Langevin equation are consistent with this wealth of recent observations. The models predict correctly that large accelerations, exceed...

The uptake kinetics of waterborne Ca and Cd, both independently and in combination, were examined in C. riparius larvae, which are extremely Cd tolerant. Larvae exposed to Ca (100-2500 micromol L(-1)), exhibited classic Michaelis-Menten saturation kinetics for Ca influx, measured using (45)Ca as a radio-tracer. The maximum rate of Ca influx (J(max)(Ca)) was 0.39 micromol g(-1)h(-1), and the Ca ...