Microbiological Community Interactions PDF

competition - may mamamatay palagi, may mananalo and matatalo antagonism -​ there's a product that comes from one then impact or harm the other -​ antibiotic: opposing life -​ can be from a fungi which harmed the bacteria FUNGAL INTERACTION -​ Why are there fungal interactions?...

competition - may mamamatay palagi, may mananalo and matatalo antagonism -​ there's a product that comes from one then impact or harm the other -​ antibiotic: opposing life -​ can be from a fungi which harmed the bacteria FUNGAL INTERACTION -​ Why are there fungal interactions? -​ morphology -​ can trigger production of their morphology modulating compounds -​ survival -​ production of antifungal compounds -​ mycoparasitism -​ protection from antibiotics/ antimycotics -​ Growth -​ bacterial growth promoting factors -​ change in nutrient availability -​ co- aggregation -​ competitive inhibition -​ virulence -​ production of virulence factors that enable them to easily invade tissues -​ bacterial precursors for fungal secondary metabolites Fungi-bacteria Interactions -​ endofungal bacteria: bacterial symbionts of fungi residing within the fungal mycelium; bacteria that resides inside a fungi -​ endosymbionts: any microbes that lives inside another organism or cells of an organisms -​ example Burkholderia produces the rice-killing toxin, rhizoxin, and enables the fungus to produce infecting spores -​ these bacteria reside in the mycelium of Rhizopus microsporus (host) which cause changes happen to the host's morphology and molecular profile, enabling it to produce infecting spores -​ pathogen of Rice : causes Rice seedling Blight Disease Fungi-Fungi Interaction -​ mycoparasitism : fungus becoming parasite of another fungus -​ mycoparasitic fungus: establishes itself as a parasite on another fungus  -​ example: Trichoderma species are applied in the biological control of fungal plant diseases -​ dalawang fungus naglalaban sila, while yung isa doon is parasite -​ Trichoderma species can be use as a biological control against the fungus that causes Rice seedling Blight Disease -​ you target the fungus not the whole plant, not use pesticides ARCHAEAL INTERACTIONS Archaea-archaea Interaction -​ symbiont Nanoarchaeum equitans directly attaches to the specialized outer membrane of Ignicoccus hospitalis and obligatory depends on the Ignicoccus host -​ outer membrane of Ignicoccus host has a specialized molecule that allows N. equitans to directly attach to it Archaea-Bacteria Interaction -​ Methanobacillus omelianskii comprises a methanogenic archaeon and a Gram- negative bacterium, which in synthrophy convert ethanol to acetate and methane BACTERIAL INTERACTIONS Virus - Bacteria Interaction -​ Bacteriophages or phages: viruses that specifically infect bacteria -​ virus main structure only consist of 1) protein and 2) DNA/RNA genetic material -​ Biological cycle of Bacteriophages -​ lytic cycle/phase: stage of a virus life cycle wherein it replicates or destroys an infected cell -​ virus will attach to the cell of the host then injects DNA to enter the cell, then learn the cell's mechanism and hijack it to reproduce/metabolize -​ cell lyses will occur: host cell will die and burst, releasing phage virions -​ lysogenic cycle/phase: wherein DNA is integrated into the host's cell DNA -​ once virus already injected its DNA and entered the host cell, the virus will integrate its DNA to the DNA Of the host cell, producing prophage  -​ asexual reproduction: prophage will split into two, bacteriophage will proliferate and easily hijacks the host cell then undergoes lytic cycle (bursting of cell) Bacteria-Bacteria Interaction -​ Quorum sensing (QS) : cell to cell communication system used by many bacteria to coordinate colony wider functions such as: bioluminescence, virulence, conjugation, and biofilm formation -​ release of AI (auto inducers), small molecules produce by bacteria that are released to communicate w/ each other, serve as their signal to ask other bacteria to join them -​ Biofilm : aggregate of microorganisms in which cells are embedded in a self-produced matrix of extracellular polymeric substance (EPS) -​ planktonic cells attached to surfaces release autoinducer in order reach a certain population density enough to form biofilm MICROBE-HOST (EUKARYOTIC) INTERACTIONS Lynn Margulis- first recognized the importance of bacteria in the evolution of higher organisms Endosymbiotic Theory -​ coevolution which help them survive over time -​ oxygen breathing bacteria -​ photosynthetic bacterium -​ larger cells can engulfed smaller cells -​ larger cells that engulfed oxygen breathing bacteria became mitochondria organelle which then evolved into animal cell -​ larger cells that engulfed photosynthetic bacterium became chloroplast organelle which then evolved to plant cell Holobiont /Metaorganism Theory -​ Holobiont: the idea that a host organism and microbes that lived in it are a single ecological unit -​ Metaorganism: further describes the totality of relationship between the host and its associated microorganisms ; the entirety of microbiota in the host makeup the metaorganism which impact different functions -​ helps the health and fitness of a host which appear to be fundamentally multi organismal where any disturbance within the complex partnership can have drastic consequences for the member's health  -​ host and microbes intensively interact and coevolve -​ EXAMPLES: -​ gut microbiome were shown to shape the tissues, cells, and molecular profile of mammalian gastrointestinal immune system during development -​ from lactic acid group -​ human digestion relies on low pH (1-2) extremely acidic -​ experiments w/ mice demonstrated that during evolution, gut microbiota affects the brain, and consequently behavior -​ ruminant gut microbiome -​ cows /ruminants have four chambers in their stomach -​ digestion happens in rumen chamber, pH level of 5 so not reliant in acidity but instead on microbiota -​ rumen home of million bacteria with enzymes that help with digestion of leafy diet rich in cellulase through fermentation -​ cows produce CH4 methane, greenhouse gas which contributes to climate change -​ zooxanthellae-corals -​ host: corals -​ polyps: tentacles of corals, has Nematocysts where you can find zooxanthellae -​ colors of corals come from zooxanthellae -​ home to several marine microorganisms -​ symbionts: zooxanthellae, microalgae eukaryotes -​ ocean photosynthesis because of planktons -​ ocean absorbs carbon dioxide which reacts with calcium carbonate (comes from marine organisms with shells), reaction product is carbonic acid -​ When the ocean gets acidic, corals get stressed then also zooxanthellae. their coral host becomes too toxic for them so they leave which results to coral bleaching and also lack of nutrients for corals since zooxanthellae are also photosynthetic -​ Anglerfish- Bioluminescent Bacteria -​ light organ: Esca -​ has chambers that enable species of Vibrio to inhabit them  -​ Vibrio species will release auto inducer for quorum sensing enticing others to colonize the chambers which will produce light for Anglerfish -​ Legumes- Rhizobium -​ Nitrogen cycle -​ atmospheric nitrogen can't be directly used by cells so it must undergo nitrogen cycle to be useful -​ lightning converts atmospheric nitrogen into certain nitrogenous compounds that are usable -​ Nitrogen fixation : nitrogen-fixing soil bacteria fix nitrogen on soil (first step to Nitrogen cycle) -​ legumes: plants (peanut, peas, etc.) -​ bacteria from Rhizobium genera lives in the root nodules of legumes and fix nitrogen to give to plants which in turn will give the bacteria carbon & lipids HUMAN- MICROBIAL INTERACTIONS -​ infection : used to imply the growth of microorganisms on or in the host -​ disease: reserved for actual tissue damage or injury that impairs the host function -​ pathogen: an organism or agent that cause disease in a host -​ if it gains access to the specific tissues it want to infect, disease will occur only if it first adhere (microbial adherence) to the tissue, multiply and yield many cells then proceeds to damage the cells Microbial Adherence -​ enhanced ability of a microorganism to attach to a cell surface -​ Process -​ Infection process: -​ must first be exposed to pathogens -​ adherence to skin or mucosa -​ invasion through epithelium -​ multiplication growth and production of virulence factors and toxins -​ Disease process -​ Toxicity: toxin effects are local or systemic -​ invasiveness: further growth at original and distant sites -​ Tissue or systemic damage -​ Adherence structures -​ flagellum : motility  -​ fimbriae : attachment to surface -​ capsule -​ sIime layers Invasion -​ the ability of the pathogen to enter into host cells or tissues, spread, and cause diseases -​ some pathogens remain localized after Initial entry -​ example: skin boil caused by Staphylococcus aureus -​ sometimes pathogen enter the bloodstream -​ Bacteremia: simple presence of bacteria in the blood; less amount of bacteria present -​ Septicemia : presence and multiplication of bacteria in the blood ; potentially life threatening, large amounts of bacteria present -​ sepsis: body reaction to septicemia Colonization -​ the growth of microorganism after it has gained access to host tissues; typically begins at sites in the mucous membranes (mucosa) -​ example: -​ Tooth decay/ Human Dental Caries -​ Streptococcus sobrinus and Streptococcus mutans are most often implicated in tooth decay Pathogenicity, Virulence, and Attenuation -​ pathogenicity: overall ability of the pathogen to cause disease -​ virulence: measure of pathogenicity, quantifiable -​ lethal dose: # of cells that pathogens kill in a test group -​ virulence factors : toxic or destructive produced by the pathogen that directly or indirectly enhance invasiveness and host damage by facilitating & promoting infection -​ Helicobacter pylori: causes ulcer ; virulence factor is can release enzyme that neutralizes acidity -​ attenuation : decrease or loss of virulence of a pathogen -​ can happen when pathogen is continuously/constantly cultured in the laboratory Enzymes as Virulence Factors -​ Coagulase: induce fibrin clotting, allows bacterial cells to remain at site of infection (prevents access to pathogens by cells of the immune response)  -​ Nuclease , Lipase: break down nucleic acids or lipids -​ Hyaluronidase: dissolves hyaluronic acid in connective tissues; allows bacterial cells to spread (enhance pathogen invasion) -​ Streptokinase: dissolves fibrin clots, allows bacterial cells to spread -​ Collagenase: breaks down collagen , allowing the bacterium to spread to other tissues -​ Gas gangrene: mabaho, nangingitim na kamay & paa -​ Protease: breaks down proteins TOXINS Toxicity : ability of an organism to cause disease by means of a toxin that inhibits host cell function or kills host cells -​ toxins are proteins -​ exotoxins: toxic proteins released from the pathogen as it grows -​ endotoxin: toxic lipopolysaccharides found in the cell wall of most Gram-negative bacteria -​ Botulinum toxin (Botox) -​ Botulism (flaccid paralysis) -​ neurotransmitter can't be released due to blockage which causes flaccid paralysis and inhibits muscle contraction -​ Tetanus Toxin -​ spastic paralysis -​ muscle keeps contracting, spasms Cholera Enterotoxin -​ carried by Vibrio cholerae -​ targets normal ion movement from lumen to blood -​ activation of epithelial adenylate cyclase : hijacks normal ion movement which cause massive water movement to the lumen -​ cholera symptom: diarrhea Fundamentals of Host Defense -​ immunity: ability of an organism to resist infection -​ innate immunity -​ myeloid precursor cell -​ non inducible, inherent -​ dont require previous exposure to a pathogen or its products for activation  -​ largely dependent on the activity of phagocytes (cells that ingest pathogens) -​ responses develop quickly within a few hours of exposure to a pathogen -​ adaptive immunity -​ lymphoid precursor cell -​ acquired ability to recognize and destroy a specific pathogen or its products -​ adaptive responses show specificity because they are directed at unique pathogen surface molecules called antigens -​ Phagocytes ingest and process antigen molecules and present them to immune cells called lymphocytes -​ the presented antigens bind specific receptors on the surface of the lymphocyte, triggering genes that promote lymphocyte multiplication and production of antigen-specific proteins called antibodies (immunoglobulins) that interact with the pathogen and mark it for destruction -​ takes several days to develop -​ immune memory: the ability to quickly produce specific immune cells or antibodies after subsequent exposure to previously encountered antigen -​ Natural Host Resistance -​ several resistance factors common to vertebrate hosts inhibit infection by most pathogens in a nonspecific way -​ nasopharynx : removal of particles -​ lysozymes -​ mucus -​ inflammation: a nonspecific reaction to noxious stimuli, such as toxins and pathogens— cytokines & chemokines (regulates immune system), produces highly concentrated phagocytes and lymphocytes causing swelling -​ fever: condition of elevated body temperature as inflammatory response -​ cytokines: stimulates hypothalamus (control center) including temp control center that releases prostaglandins which increase body temp -​ natural killer cells (NK cells): cytotoxic lymphocytes that are distinct from T and B cells. They seek out and destroy compromised cells, such as cells infected by intracellular pathogens (viruses) or cancer cells -​ interferons ( alpha & beta) : small proteins in the cytokine family that prevent viral replication by stimulating production of antiviral proteins in uninfected cells ; innate defense