Light responses (ReP) and pre-stimulus membrane potential (PMP) and conductance of photoreceptors of Astacus leptodactylus and Limulus polyphemus (lateral eye) were recorded and changes were observed when the photoreceptor was depolarized by the action of external ouabain of high potassium concentration application. 1 mM/1 ouabain application causes a transient increase of PMP and ReP in Limulu...

Rapid range expansion is one of the major attributes of invasion success. During range expansion, dispersing individuals face a novel environment where trade-offs between benefits of reduced conspecific density and pressure from niche competitors may differentially affect life-history traits essential for population growth. In this study, we examined differences in sex ratio, body condition, ph...

The exchange (release resp. uptake) of K+, Rb+, and Na+ ions in the isolated retina of the crayfish Astacus leptodactylus with the surrounding medium was measured using flame photometry and radioisotopic techniques. 1. The net release of K+ into a Na+ and K+ free, choline containing medium, as measured by means of flame photometry, is increased by illumination. 2. The release of 86Rb+, used as ...

Crayfish stocks collapsed in Turkey in mid 1980’s due to crayfish plague epidemics, with up to 25% survival in some cases. The collapsed stocks have then recovered slowly and commercial crayfish fishery was reinitiated gradually within a decade. We examined the prevalence of Aphanomyces astaciDNA in the narrow clawed crayfish (Astacus leptodactylus) collected from two Turkish lakes, Lake İznik ...

The crustacean Hyperglycemic Hormone (cHH) is present in many decapods in different isoforms, whose specific biological functions are still poorly understood. Here we report on the first chemical synthesis of three distinct isoforms of the cHH of Astacus leptodactylus carried out by solid phase peptide synthesis coupled to native chemical ligation. The synthetic 72 amino acid long peptide amide...

Tyrosinases, which are widely distributed among animals, plants and fungi, are involved in many biologically essential functions, including pigmentation, sclerotization, primary immune response and host defence. In the present study, we present a structural and physicochemical characterization of two new tyrosinases from the crustaceans Palinurus elephas (European spiny lobster) and Astacus lep...