Small HSPs molecular weights as new indication to the hypothesis of segregated status of thermophilic relict Gmelinoides fasciatus among baikal and palearctic amphipods

Among the great diverse of Baikal fauna of amphipods (more than 350 species and subspecies) Gmelinoides fasciatus (Stebbing 1899) takes the special place. It is characterized by a high morphological variability and wide thermal-adaptive possibilities. By common opinion G. fasciatus is a thermophilic relict segregated from other Baikal temperature sensitive amphipods' fauna. In present study we tested hypothesis of segregated status of G. fasciatus among some Baikal and some Palearctic amphipods using of heat-shock proteins’ (HSP) molecular weight as comparative biomarkers. We used heat-shock proteins (HSP) from two families: HSP70 and small HSP (sHSP) immunochemically related to α-crystalline. 15 species of Baikal amphipods from different genera and families and 2 Palearctic species from genus Gammarus were tested. It was shown, that molecular weights of HSP70 were the same in all investigated species and corresponds close to 70 kD. In the contrast, the molecular weights of sHSP in G. fasciatus was 37 kD and differed from all other species, in which molecular weights of sHSP were 35 kD. In sum, this study showed that sHSPs molecular weights may relate to evolutional differences between the close related species. Additionally, obtained data can be taken as new indication of segregated status of thermophilic relict G. fasciatus which linked with its phylogenetic history in Lake Baikal

Sub-littoral and supra-littoral amphipods respond differently to acute thermal stress

Thermal tolerance was determined in two closely related amphipod species from contrasting environments (sub-littoral and supra-littoral zones of the sea) using HSP expression and the activity of antioxidant enzymes. The levels of HSP70 and small HSPs present in untreated control animals were higher in the supra-littoral Orchestia gammarellus than in the sub-littoral Gammarus oceanicus. Under the acute thermal stress, HSP levels increased less strongly in O. gammarellus than in G. oceanicus. Activities of antioxidant enzymes peroxidase, catalase and glutathione S-transferase, were more pronounced in the supra-littoral O. gammarellus then in the sub-littoral G. oceanicus. We conclude that the environmental temperature regime modifies key cellular defense mechanisms in amphipods. Higher levels of constitutive HSP synthesis and higher levels of antioxidant enzymes in the supra-littoral species likely reflects adaptation to this highly thermally variable environment

Preliminary Analysis of Hemocyanins in Hemolymph Plasma of Baikal Endemic Amphipods

Two-dimensional electrophoresis of plasma hemolymph proteins of several endemic Baikal amphipod species showed that, as expected, hemocyanin is the main major protein in plasma of these species. Isoforms of hemocyanins form on the gels maximum 24 separate spots with slightly different molecular weight and vary by their isoelectric points. Analysis of transcript sequences of hemocyanin of Baikal amphipod Eulimnogammarus verrucosus revealed a broad heterogeneity of hemocyanin isoforms, which were divided into 2 distinct groups on their amino acid sequence and have different calculated molecular weight and isoelectric points. The β-type of hemocyanin has been described for percarid crustaceans for the first time

COMPARISON OF STRESS PROTEINS PARTICIPATION IN ADAPTATION MECHANISMS OF BAIKALIAN AND PALEARCTIC AMPHIPOD (AMPHIPODA; CRUSTACEA) SPECIES

The aim of the present study was a study of the influence different stressful factor on syntheses and activity of the stress proteins (HSP70, sHSP and peroxidase) of freshwater organism. Six freshwater amphipod species were investigated: Eulimnogammarus cyaneus (Dyb.), E verrucosus (Gerstf.), E vittatus (Dyb.) - endemic species from Lake Baikal which were compared with Palearctic species - Gammarus lacustris Sars., G tigrinus (Sexton), Chaetogammarus ischnus (Stebbins). It was shown expression of sHSP by heat and toxic stresses for all amphipods species. Oxidative stress induced HSP70 for Palearctic species G tigrinus and C ischnus but not for baikalian species. Heat stress did not caused the increase of HSP70 level for Baikalian species of amphipods. The activity of the peroxidase was decrease by heat and toxic stresses. Oxidative stress caused the increase of peroxidase activity for Palearctic species, and the decrease for Baikalian once