🧬 1. Microbial Biochemistry & Energy Acquisition

--- Types of Trophs: Autotrophs : Synthesize their own food from inorganic sources. Heterotrophs : Require organic compounds for nutrition. Photoautotrophs : Use light energy to fix CO₂ (e.g., cyanobacteria). Calvin Cycle: Central pathway for carbon fixation in photoautotrophs. Converts CO₂ → glucose using ATP and NADPH from light reactions. Key enzymes : RuBisCO, G3P dehydrogenase, etc. Importance : Foundation of photosynthetic energy storage. Modern Concepts in Energy Acquisition: Diversity of metabolic strategies: Chemolithotrophy Phototrophy Fermentation Aerobic/anaerobic respiration --- 2. Principles of Medical Microbiology Historical Contributors of Medical Microbiology : Louis Pasteur : Germ theory, rabies vaccine. Robert Koch : Koch’s postulates, TB bacterium. Joseph Lister : Antiseptic surgery. --- 3. Prokaryotic Cell Structures External Structures : Capsule : Anti-phagocytic; immune evasion. Cell wall : Gram-positive : Thick peptidoglycan, teichoic acids. Gram-negative : Thin peptidoglycan + outer membrane with LPS . Flagella : Motility. Fimbriae/Pili : Attachment and conjugation. Internal Structures : Plasmids : Extrachromosomal DNA; often carry resistance genes. Ribosomes : 70S. Nucleoid : Circular DNA. --- 4. Antibiotics and Resistance Antibiotics Overview : Classes: Penicillins, Aminoglycosides, Macrolides, etc. Targets: Cell wall, protein synthesis, nucleic acid synthesis. Mechanisms of Resistance : Genetic transfer : Transformation, conjugation, transduction. Enzymatic inactivation : e.g., β-lactamases. Target modification . Efflux pumps . Types of Action : Bacteriostatic : Inhibit growth (e.g., tetracycline). Bactericidal : Kill bacteria (e.g., penicillin). --- 5. Viruses and Pathogenesis Viral Pathogenesis : Types of infection : Productive : Virus replicates and lyses host. Abortive : Entry occurs, but no replication. Latent : Virus remains dormant (e.g., HSV). Latency & Immune Evasion : Latency : Viral genome persists in host without expression. Immune escape :Hiding in neurons (e.g., HSV) Downregulating MHC I Antigenic variation Importance of Viral Spikes : Spikes = surface glycoproteins (e.g., hemagglutinin in influenza). Function : Host cell attachment and entry. Mutations in spikes → antigenic drift/shift (esp. in flu virus). --- 6. Virology - Specific Topics Retroviruses : RNA viruses that reverse transcribe into DNA (e.g., HIV). Viral latency : Integration into host genome. Immune evasion via antigenic variation and hiding. Phages : Bacteriophages = viruses that infect bacteria. Can transfer resistance genes. Used in phage therapy. --- 7. Antiviral & Antiretroviral Drugs Antiviral Drugs : Target various stages of viral replication: Entry inhibitors Uncoating inhibitors Nucleoside analogues (e.g., acyclovir) Protease inhibitors Antiretroviral Therapy (ART) : Used in HIV treatment. Common classes: Reverse transcriptase inhibitors (NRTIs, NNRTIs) Protease inhibitors Integrase inhibitors Entry inhibitors --- ---