The bicarbonate compensation concentration (BCC) measmed in Scenedesmus quadricauda increased significantly with increasing total alkalínity (TA): ířom 2-5 inmol(HC03') m'^ at an alkalinity of 0.5 mol m'^ to 416-444 mmol(HC03") m"^ at an alkalinity of 10 mol m'^. This should be taken into account when evaluating a species ability to use HC03’. The increase of BCC at higher alkalinities could be caused by carbonate inhibition of HC03‘ uptake and/or by extremely high assimilatory pH reached.
The aim of this study was to investigate the post-cyclic transmission of Acanthocephalus tumescens (von Linstow, 1896) from Galaxias maculatus Jenyns to Oncorhynchus mykiss (Walbaum). Wild G. maculatus naturally infected with A. tumescens were fed to cultured rainbow trout, which were sacrificed at the second, third and fourth weeks post infection. Normally attached male and female acanthocephalans were recovered alive from the intestine of rainbow trout. Parasites survive at least four weeks post infection, growing and attaining full sexual maturity. Prevalence and mean intensity generally decreased after infection. A. tumescens is the eighth acanthocephalan species in which post-cyclic transmission has been proven.
The review of the 16 years history of the Hubble Space Telescope is presented. After the correction of its spherical aberration Hubble Space Telescope becomes very important and successful astronomical apparatus on the Earth orbit. In the course of those 16 years the Telescope obtained many results. A few of them are presented in this review as examples of Hubble Space Telescope activities.