BIOMED NOTES 24/25

Holobiont = humans are superorganisms composed of human and microbial cells evolving together  Microbes = essential partners  Balance vs imbalance, good vs bad  Microbiome = combined genetic material of microbes in a particular environment  Microbiota = microbes in specific environment  Types of microbes:  Bacteria - firmicutes - Strep Lacto, bacteriodetes, proteobacteria - Klebsiella Enterobacter, actinobacteria  Virus  Fungi - basidomycota, ascomycota  Archaea Protist  Distribution of microbes: ✓ Skin - Actinobacteria - Propionibacterium acnes, Cornyebacterium 1000 21% Mouth 600+ 26% Upper respiratory tract 600+ 14% GIT 25 in stomach 500-1000 in intestine 29% Urogenital tract - Lactobacillus 60sp 9% Functions:  Metabolic contribution  Promote tissue integrity and development  Immune modulation  Protection from pathogens  Roles:  Facilitate nutrients and vitamin acquisition  " Stimulate innate a...

Factors make microbes thrive: GERM SEP Genetic exchange  Ecological interaction  Rapid reproduction  Metabolic versatility  Small size & large surface area  Extreme adaptability  Pervasive environment presence  Factors govern microbial growth:  Resources: carbon, nitrogen, micronutrients SPK Mg, electron receptor sulphate, inorganic electron donors H2 Environmental: temperature, water, pH, oxygen, light, osmotic conditions  Biological: competition for space and resources, predation, symbiosis  Environment reservoir: ✓ 1. Soil CBB Clostridium tetani  Bacillus anthracis  Burkholderia pseudomallei - wet soil, rice paddy, stagnant water  2. Water Freshwater   Vibrio cholera - flood  Leptospira interrogans - rice field, flood  Free living amoeba   Acanthamoeba - granulomatous encephalitis  Naegleria fowleri - warm freshwater - PAM Biofilms in water systems  LP PA Legionella pneumophila - hosp...

Fungal structure:  Spore sexual: asco, basidio, zygo  Spore asexual: conidia, sporangiospores  Hypha Pseudohyphae  Coneocyte  Septa  Mycelium  Cell wall: chitin, beta glucans, mannans, glycoprotein  Cell membrane: ergosterol  Acquisition → adhesion/colonization → invasion → immune evasion/proliferation → damage  Routes of infection: ✓ Inhale  Trauma/inoculation  Colonization overgrowth  Ingestion  Thermotolerance = able to grow at 37°C  Virulence factors  1. Structural factors  Capsule: galactoxylomannan induces T cell apoptosis, glucoxylomannan inhibit phagocytosis  Melanin - uv, free radicals  2. Enzymatic factors  Protease degrade collagen, elastin, IgA by candida  Phospholipase disrupt membrane by candida, cryptococcus  Urease alkalinize environment by cryptococcus  3. Morphological factors  ✓ Dimorphism  Biofilms  Phenotypic switching = white-opaque chan...