Quantitative characterization of different strains of Saccharomyces yeast by analysis of fluorescence microscopy images of cell populations.

Much of our knowledge concerned with microbial cells is based on population-based analysis of cultures, which give useful insights into average responses but neither on individual cells nor subpopulations. In this work we demonstrate how to access and utilise large amounts of valuable information concerned with cell populations contained in laser scanning microscopy images. To this aim we carried out quantitative characterization of selected strains of Saccharomyces yeast by image and statistical analysis of the Laser Scanning Microscopy images.

Characterization of yeast strains by fluorescence lifetime imaging microscopy.

The results of fluorescence lifetime imaging microscopy of selected yeast strains were presented and the fact that the lifetime distributions can be successfully used for strain characterization and differentiation was demonstrated. Four strains of industrially relevant yeast Saccharomyces were excited at 405 nm and the autofluorescence observed within 440-540 nm. Using statistical tools such as empirical cumulative distribution functions with Kolmogorov-Smirnov testing, the four studied strains were categorized into three different groups for normal sample size of 70 cells slide(-1) at a significance level of 5%.

Fluorescence amplification by electrochemically deposited silver nanowires with fractal architecture.

Electrochemically deposited silver structures with nanowires 50-100 nm in diameter show high fluorescence amplification and strongly reduced fluorescence lifetimes. Both quantities depend on the structure thickness. With increasing thickness the fluorescence amplification proportionally increases and the fluorescence lifetime decreases.

Stromatolite reef from the Early Archaean era of Australia.

The 3,430-million-year-old Strelley Pool Chert (SPC) (Pilbara Craton, Australia) is a sedimentary rock formation containing laminated structures of probable biological origin (stromatolites). Determining the biogenicity of such ancient fossils is the subject of ongoing debate. However, many obstacles to interpretation of the fossils are overcome in the SPC because of the broad extent, excellent preservation and morphological variety of its stromatolitic outcrops--which provide comprehensive palaeontological information on a scale exceeding other rocks of such age.