We investigate the role of recombination in transposable element (TE) proliferation in the cyclical parthenogen, Daphnia pulex. Recombination provides a mechanism by which the rate of both TE gain and loss can be accelerated, a duality that has long intrigued many biologists interested in the influence of sex on mutation accumulation. We compared TE loads among populations of D. pulex where sex...

The acute toxicity of Tl(I) to the microalga, Pseudokirchneriella subcapitata, the planktonic crustaceans, Daphnia magna and Daphnia pulex, and early-life stage of the zebrafish, Danio rerio, has been studied according to OECD protocols. Toxicological end-point concentrations for the microalga ranged from 17 μg l(-1) for a 72 h EyC25 (yield inhibition) to 80 μg l(-1) for a 72 h ErC50 (growth in...

Previous studies have demonstrated that certain pesticides, including carbaryl and endosulfan, can modulate the expression of predator-induced morphology in Daphnia. These pesticides affect the transmission of nervous impulses in vertebrates and invertebrates. The aim of this study was to determine the role of two neurotransmitter systems, excitatory cholinergic transmission and inhibitory gamm...

Evolutionary adaptation could assist organisms to cope with environmental changes, yet few experimental systems allow us to directly track evolutionary trajectory. Using experimental evolution, evolutionary tolerance to Microcystis aeruginosa was investigated in two cladocerans (Daphnia pulex and Simocephalus vetulus) to test the hypothesis that cladoceran grazers rapidly adapt to toxic cyanoba...

Daphnia pulex were reared in 50 ml flasks, each containing 1, 20 or 40 individuals, which were serially connected with a 20-mum mesh screens between, in order to examine the effect of physical interference due to crowding on shifts of life history traits throughout two consecutive generations. A flow-through system, designed to maintain a sufficient food supply and minimize the accumulation of ...

A taxonomic study of the genus Ocellarnaca Gorochov, 2004 was presented. Four new species were described: O. omeica sp. nov., O. coomani sp. nov., O. xiai sp. nov., O. brevicauda sp. nov.. A key to the species and the distributional data of Ocellarnaca were provided. 

In this study, the oxidative stress effects of cadmium (Cd) toxicity depending on water temperature were investigated Gammarus pulex. The test organism individuals exposed to sublethal concentrations for 96 hours at certain rates (C1; 1/10, C2; 1/20 and C3; 1/40) LC50 values Cd each (10, 14, 18 °C). Malondialdehyde (MDA) level, glutathione peroxidase (GPx), catalase (CAT) enzyme activities temp...

marine ecosystem pollution is one of the important problems of today environment. in this study the existence of heavy metal in the namrood river, situated in firoozkooh in tehran province, iran has been investigated. the namrood river is located near firoozkooh route, and is affected by pollutant from tourist centers, entertainment, gas stations, nearby villages’ sewage systems, farming efflue...

Environmental contamination is a common cause of rapid evolution. Recent work has shown that Daphnia pulex, an important freshwater species, can rapidly evolve increased tolerance to a common contaminant, sodium chloride (NaCl) road salt. While such rapid evolution can benefit organisms, allowing them to adapt to new environmental conditions, it can also be associated with unforeseen tradeoffs....