Dynamics of skeleton formation in the Lake Baikal sponge Lubomirskia baicalensis. Part I. Biological and biochemical studies

In ancient Lake Baikal (East Siberia), freshwater sponges have diversified to an extraordinary degree. The skeleton of Lubomirskia baicalensis, which attains a size of up to 1 m, is constructed from spicules, which are cemented into longitudinal bundles. Our X-ray analysis revealed that the architecture of the specimens follows a highly ordered radiate accretive growth pattern. The spicules have a central axial canal with an axial filament inside. This organic filament is composed of silicatein, the major enzyme involved in silica formation of the spicules. We found that the specific activity of silicatein in samples from the non-growing (basal) zone is much lower than in those from the growth zone (tips) and that even the composition of this molecule differs in these regions. The present study shows for the first time that the turnover of silicatein, the major element of the axial canal of sponge spicules, changes within a sponge specimen depending on the region in which it is found.     

Photo-Akustik-Spektroskopie an festen Stoffen

A short historic introduction into the subject and the basics of the generation of a photoacoustic signal with the emphasis upon the particularities of solid samples are given. The set-up of a two-beam photoacoustic spectrometer is described. For a better understanding of the investigations of solid samples the basic theory is presented. Specially treated subjects are: the saturation effect and how to overcome it; depth profiles of thin layers as a nondestructive method used in the investigation of a green leaf and a sheet of color reversal paper; the investigation of solid solutions in a polymer matrix with the determination of the thermic data of the matrix itself, and the fluorescence quantum yield of organic dyes solved therein. Finally a summary of numerous other applications of the PAS is given.     

The lumisphere,a new model of pre-biotic evolution

Lyophilization of the amber-colored, fluorescent oils obtained via thermolysis of amino acid mixtures (Lys, Ala, Gly) leads to a cellular-structured material—with an average cell diameter of 50 μm. The cellular aggregates show a resemblance to epithel tissues. Single cellular entities find their analogs in Fox microspheres as well as in the microfossilsIsuasphaera. Short-wave UV (254 nm) irradiation of the aqueous suspensions destroys the cells, whereas suspension in saline solutions (NaCl) offers protection against dissolution by UV light. The fluorescence spectrum of the microscopic preparations containing the highly fluorescent cellular material (“lumispheres”) was registered.