The purpose of the study was to optimize the removal of Cr(VI) by means of the Trichoderma viride strain isolated from chromium mud samples a well as the Aspergillus niger and Penicillium citrinum strains from other environments. The growth of organism and removal of chromium(VI) was carried out in water solution of various chromium(VI) contents. The research was carried out at optimal pH for each fungus i.e. Aspergillus niger 4.0, Penicillium citrinum 5.0 and Trichoderma viride 4.5. During 14 days of incubation, samples of 5 ml each were collected every day in order to determine chromium(VI) content in the solution and the efficiency of bioaccumulation of this element was then specified. Furthermore, chromium contents in filtrate and mycelium were checked to verify this type of biological activity of microorganisms. The fungi culture investigated in this study could grow at 10-125 mg/l chromium concentration which indicated that it was characterized by high tolerance to various concentrations of chromium. At 125 mg/l chromium, these organisms could accumulate successfully about 90% of chromium. High tolerance of this culture can make it a potential candidate to be a heavy metal scavenger of chromium.
O b j e c t i v e s: To evaluate the properties of natural sweetener solutions in whole organ preservation and assess their influence on the dimension, weight and shape of cardiac tissue samples in stated time intervals, up to a one-year period of observation. B a c k g r o u n d: Tissue fixation is essential for biological sample examination. Many negative toxic effects of formaldehyde-based fixatives have forced us to seek alternatives for formaldehyde based solutions. It has been demonstrated that natural sweeteners can preserve small tissue samples well and that these solutions can be used in histopathological processes. However, their ability to preserve whole human organs are unknown. M e t h o d s: A total of 30 swine hearts were investigated. Th ree study groups (n = 10 in each case) were formed and classifi ed on the type of fixative: (1) 10% formaldehyde phosphate-buffered solution (FPBS), (2) 10% alcohol-based honey solution (ABHS), (3) 10% water-based honey solution (WBHS). Samples were measured before fi xation and in the following time points: 24 hours, 72 hours, 168 hours, 3 months, 6 months and 12 months. R e s u l t s: The WBHS failed to preserve heart samples and decomposition of tissues was observed one week after fixation. In half of the studied parameters, the ABHS had similar modifying tendencies as compared to FPBS. Th e overall condition of preserved tissue, weight, left ventricular wall thickness, right ventricular wall thickness and the diameter of the papillary muscle differed considerably. C o n c l u s i o n s: The ABHS may be used as an alternative fi xative for macroscopic studies of cardiac tissue, whereas the WBHS is not suited for tissue preservation.
The fusulinid foraminifers of Schellwienia arctica (Schellwien, 1908) have been investigated from Polakkfjellet Mt., south Spitsbergen, and used as biostratigraphic marker for the latest Carboniferous earliest Permian strata of the Treskelodden Formation. A series of thin sections enable to investigate the internal structure and growth pattern of individual specimens. The observed variation of growth suggests dynamic environmental conditions at the investigated location and most likely over one-year long life span of this foraminifer.