Nutrients and Environmental Factors for the Growth of Nostoc commune Cells Infection and Migration of Marked Rhizobia in Alfalfa (Medicago sativa) Bud Seedlings under the Action of Exogenous Substances CHARACTERIZATION OF EXOPOLYSACCHARIDES FROM Alcaligenes faecalis AND ITS MUTANTS PURIFICATION AND ANALYSIS OF EXOPOLYSACCHARIDES FROM Alcaligenes faecalis AND ITS MUTANTS Components of exopolysaccharides of Nitzschia closteriumand preparation of their sulfated products Effects of Salt Stress on Carbohydrate Metabolism in Desert Soil Alga Microcoleus vaginatus Gom. Effects of Bacillus pumilus on Biomass and β-carotene Accumulation in Dunaliella salina SZ-05 Freezing properties of Antarctic bacterial exopolysaccharides solutions by differential scanning calorimetry Optimization of Extraction for Exopolysaccharides from Grifola Frondosa