15179 - Microbiology Applied to Animal-based Productions

Learning outcomes

The student knows the fundamentals of the biology of microorganisms, has elements of soil microbiology, knows food and feed fermentation (silage), as well as basis of food hygiene. In particular, the student is able to handle the elements of dairy and meat microbiology.

Course contents

Introduction. What is microbiology and general descriptions. Difinition of microrganism: composition and functions of the microbial cells. Eukaryotic and prokaryotic cells: differences and common traits.

Structure of cells. Morphology of bacterial cells; cell wall, peptidoglycan. Gram stain; Gram positive and Gram negative bacteria; External membrane and periplasmic space in Gram negative bacteria. Cell membrane; structure and functions. Membrane embedded proteins and membrane fluidity. External structures (S-layer, capsules e exopolysaccharides). Motility organelles. Bacterial taxes. Cytoplasm. Ribosomes. Endospore formation. Morphology of eukariotic cells: wall, chloroplasts and mithocondria. Nucleous and chromosomes. Endoplasmatic reticulum. Golgi apparatus.

Microbial growth . Culture media: definition, classification, preparation. Micronutrients. Microbial counting. Microbial growth curve: lag, exponential, stationary ans death phase. Diauxic growth. Main factors able to influence growth curve: temperature, pH, aw and oxygen.

Nutrition and transport systems . Chemical component of cells. Energy (phototrophy, chemiotrophy, lithotrophy). Organic substance (autotrophy and organotrophy). Growth factors. Transport systems (primary, secundary group translocation).

Microbial metabolism . Energetic strategies. Fermentation and respiration. Electronic chain, redox potential and bioenergetics. Membrane carrier (NADH, quinones, cytochrome, Fe S proteins, flavoproteins) and Proton Motive Force (PFM) generation of PFM.

Energetic pathways . Glicolysis, Entner Doudoroff pathway. Oxidation of pentose phosphate. Fermentations: homolactic, heterolactic, alcoholic, mixed acid, butandiolic, acetic, butyric, propionic, homoacetic, bifidobacteria pathway, Stickland reaction. Aerobic and anaerobic respiration. Krebs cycle.. Catabolism of macromolecules. Nucleic acids, proteins, polysaccharides, lipids.

Assimilative metabolism and biosynthesis . Key intermediate products. Gluconeogenesis. Calvin pathway. Nitrogen assimilation. Ammonia and ammonium ion assimilation. Nitrate assimilation Sulphur assimilation. Phosphate assimilation. Aminoacid biosynthesis, Nucleotide biosynthesis. Fatty acid biosynthesis

Bacterial genetic . Bacterial genome and nucleoid. Chromosome organization. Mobile genetic elements in bacteria. Plasmids, transposones, integrons, insertion sequences, viral genomes. Replication, transcription and translation of genetic information. DNA replication and enzymes involved. Replication of chromosome: enzyme involved in replisome. Transcription: phases, mRNA role, sigma factor. Translation: tRNA, genetic code, protein synthesis, ribosome functions and characteristics. Role and function of operons. Regulation od transcription. Mutation and mutagenesis. Recombination, Horizontal genetic transfer: transformation, transduction and conjugation.

Virus: Viral structure. Genetic material in viruses. Steps of viral replication. Proteine virali. Bacterial viruses (fagi). Virulent fagi virulenti and temperate fagi. Characteristic of lysogenic fagi

Bacterial classification. Phylogenesis. Methods for classification; genotype and phenotype. Definition of microbial species. Taxonomy of Bacteria: most important Phyla (Proteobacteria, Firmicutes, Actinobacteria). Characteristics of the main microbial groups: Pseudomonadacee, Enterobacteriacee, Acetobacteraceae, Acinetobacter and Chromobacterium, Vibrio e Photobacterium, lactic acid bacteria, Bacillus, Clostridium, Staphyilococci, Micrococci, Listeria, Corinebacteria, propionic bacteria, bifidobacteria. Taxonomy of fungi: yeasts and moulds.

Microorganisms and foods of animal origin: spoilage, pathogenic and toxinogenic microorganisms. Fermented foods: introduction to dairy products (cheeses and fermented milks) and fermented meats

Practical training in laboratory . Microscope. Microbial growth curves: counting anddefinition of the different phases of the curve through direct (plate counting) and indirect (optical density) methods. Microbiological sampling through plate counting (superficial or immersion inoculum).Counting and identification of the microbial concentration in a food samples for different microbial groups. Isolation of microorganisms. Purification and characterization of isolates. Optical microscope (cell morphology) and test of catalane. Fermentation trials.

Readings/Bibliography

Microbiologia Generale ed Agraria (a cura di Claudia Sorlini e Bruno Biavati). CEA Editrice Milano

 

Microbiologia alimentare applicata (a cura di Luca Cocolin, Marco Gobbetti, Erasmo Neviani) CEA Editrice Milano

Teaching methods

Theoretical lessons and practical training in laboratory

Assessment methods

The preparation of the students will be tested through a test with two types of questions. There are three open questions for each of which a maximum score of three points will be assigned. Then there are 24 multiple choice questions, for each of which a maximum of one points will be assigned. The time available to complete the test is 120 minutes. Text books, notes, and other tools are not admitted. The test is passed if a score of 18 points is reached. Score of 33 determines the obtaining of laude.

Teaching tools

Slides of the lessons

Office hours

See the website of Fausto Gardini