General Microbiology

Objective The student should acquire a correct view of the microbial world with a specific attention to the microbial applications, quality and safety problems realted to the food area. Teaching program:Microorganism definition. Description and use of the phase-contrast microscope. The procaryotic and the eucaryotic cell. Description of cell composition and structures. Composition, structure and function of cell membrane and cell wall. Description of teichoic-lipoteichoic acids and exopolysaccharides. The membrane transport systems. The chemical composition of the cell and the nutritional requirements. The composition of a microbiological media: solid and liquid media. The sterilization procedure. The microbial growth: the growth in bacteria and in the yeast Saccharomyces cerevisiae. Description of the growth curve. Description direct and indirect methods for microbial count. The energetic metabolism. The respiratory metabolism and electron chain transport. Glycolysis, homo- and heterolactic fermentation and lactic acid bacteria, the TCA cycle, the ethanol fermentation of S. cerevisiae, the acetic fermentation, the acetic metabolism and the acetic bacteria. The anabolism and the definition of auxotrophy and prototrophy. The anaplerotic reactions. Principle of microbial genetics: the structure and composition of DNA and RNA. The DNA replication. The genetic code. The transcriptional gene organizations. The RNA synthesis, the protein synthesis. Gene regulation: example of positive and negative gene-regulation. The mutations and the mechanisms of gene repair. Plasmids and virus. The mechanisms of phage resistance. The horizontal gene transfer mechanisms: conjugation, transduction and transformation. Principle of bacterial taxonomy: the species definition, the polyphasic approach in the species identification. The 16S rRNA gene in the taxonomy of living organisms. The PCR reaction: principle and applications. Description of sporeforming bacteria and enteric bacteria. Fungal taxonomy. Practical laboratory exercisesDuring the microbiology laboratory lessons the student will do practice in isolating pure bacterial culture from sample of soil, yogurt and fermented meat. The student will apply the viable count method to evaluate the total microbial count in the above mentioned samples. The student will learn to use a phase-contrast microscope to observe fresh cell suspension of bacteria and yeasts and to identify the Gram type of the strain isolated in pure culture for the samples described above. Moreover, the student will learn how to use different media in order to test the amylolytic and proteolytic activities of bacterial cultures.