MICROORGANISMS AND HUMANS Section1: DSE Bio Elective 3 Microorganisms and Humans Quick Review O line: 1. Microbiology 2. Use of Microorganisms 3. Microbial Genetics 4.Harmful Effects of Microorganisms ② ① Attachment I. Microbiology
② oo• Life cycle of a virus Penetration ¥14, ✓ "⑤ Release 1. Attachment The virus attaches itself to host cell Synthesis of viral components
2. Penetration t L ④ It injects its genetic content (DNA/ RNA)÷③④Assembly 3. Synthesis of viral components Viral genetic content takes over the host cell’s metabolism to synthesise new viral DNA/RNA and protein coat respectively
4.Assembly New viral DNA/ RNA and protein coat assemble into new virus inside host cell
5. Release Once the host cell’s resources are exhausted, newly formed viruses will lyse the host cell and spread to infect nearby cells ***Viruses are cell-type specific/ species-specific ***Viruses without host cell will disintegrate rapidly ***Growth of viruses are different from other living things * Note (Latent period) Viral nucleic acids (DNA/ RNA) may be integrated into host cells DNA and replicated along with host cell’s DNA during cell division During latent period, no new viruses are produced Viral genes are activated later oooo Growth of microorganisms * Growth requirement 1. Supply of carbon source→ eg. Dead organic matter for decomposer 2. Supply of =nitrogen source→ eg. Nitrogen gas for nitrogen fixing bacteria
3. Suitable Temperature and Suitable. pH - - → 4. Supply of- oxygen eg.aerobic respiration required for aerobic bacteria
5.Supply of -water
* Stages of growth of microorganisms
A
Logarithm of living bacterial cells L . Time 1. Lag phase a.Adaptation of bacterial cell b.Synthesis of proteins and ATP 2. Exponential/ Log phase→ Max. growth a.Maximum growth rate under favourable conditions 3. Stationary phase→ growth rate=death rate a.Depletion of nutrients b.Accumulation of toxic waste 4. Death phase→ growth rate II. Use Microorganisms Baa Food processing a. Beer-brewing/ Bread-making/ Wine-making ORising Temperature - p q ( Enzyme) :ol Acti ve IT ' EH Anaerobic ORespiration (Sugar I Source) . o w. ¥ Stirring o¥i÷÷÷aRespiration ¥ - xMicrobes Killed # oHeating ⑨ b. Production of yogurt [Pre-heating] Microbes Milk Killed IT [Adding. Lactic Acid] ⇐ Thicken The Milk Cool ¥ [Cooling] ⇐ ¥ Yogurt ••2. Antibody production ÷ ofE¥ → Antibody Microbes Fungi Bacteria t Nutrients Q Extraction . ••2. Vaccine production ' ' → → a Toxins ÷÷÷÷÷ Pathogens Vaccine ••2.⑧ Industrial enzymes a. Proteases and lipases from bacteria that could withstand alkaline environment→ used in biological washing powder to remove stains PH>7 4 Lipases Dress → Proteases the b. Pectinases from fungi to catalyse the breakdown of pectin in cell wall of fruit cells for extra fruit juice extraction Pectin Pectinases Breakdown Catalyse In Cell Wall → EH Juice •••2. Sewage treatment •Factory & Household Screening ¥FwSolids, Grits Sedimentation Sludges . Fuel Fertilizer Aerobic Decomposition Organic Substances ¥÷EDisinfection ET Pathogensw 2. Biogas production Agricultural Industrial Food Animal ••Waste③ Waste DOWaste 0Waste Collection of Organic Waste Organic waste To Pretreatment Fertilizer CSTR Digesters Bio Desulphurization Decomposition by Anaerobic Bacteria Self-sufficient . Electricity Gas-powered Biogas Holder Generator Collection of Fuel Excessive Electricity III. Microbial Gen ics • Potential hazards: 1. Cause allergic response 2. Production of superbug 3. Transfer of GM genes to wild type IV. H mful Effects of Microorganisms Toxins a. Food poisoning→ caused by toxins produced by microorganisms .÷÷k÷. b. Food-borne infection→ caused by pathogenic microorganisms present in food A.it#E*.E.E*E.EEE.a... o• Controlling growth of microorganisms 1. Physical method a. Filtration→ avoid contact b. Heating→ kill microorganisms i. boiling/ autoclaving maidens ii.Pasteurization of milk iii.Ultra high temperature treatment in milk c. Exposure to low temperature→ limiting microbial growth and enzymatic activities i.Refrigeration ii.Freezing B. d. Drying→ dehydrate microbes to inhibit growth i.Natural-drying ii.Freeze-drying iii.Adding of large amount of salt/ sugar e. Irradiation→ high energy radiation to damage microbial DNA/ proteins 2. Chemical method a.Disinfectant/ Antiseptics→ kill microorganisms b. Antibiotics→ kill/ inhibit growth of microorganisms c. Preservatives→ slow down/ inhibit the growth of microorganisms d. Acids→ low pH to denature enzymes in microorganisms MICROORGANISMS AND HUMANS Section2: How is Synthetic biology related in these Topics O line: 1. Phage Lytic Cycle 2. Bread Making 3. Sewage Treatment I. Phage lyric cycle (2018 iGEM Evry Paris-Saclay) Q. What will happen if bacteriophage only has lytic cycle (the cycle you learnt) to infect bacteria??? In an isolated environment, phages might not be able to survive eventually, because all bacteria might be infected by phage and are lysed. Phages might lose all host cells to continue its survival. Therefore there is another cycle of infection of phages----Lysogenic cycle. The phages integrate their nucleic acid to the host cell’s genome and are passed to the daughter cell. Therefore only lysing the daughter cell instead of the host cell. →→ In this way the bacteriophages could get a constant reproduction of itself!!! And actually a phage that enters a bacterium early infection will follow the lytic cycle by default. And there are ways that allow the phage to switch its ‘hunting mode’ from lytic to lysogenic… And the switching is because of an amino acid secreted outside of the cell controlled by a gene called aimP. ② ⇒ a¥ s :*' y ÷ aimP Switch from lytic to lysogenic :¥. a " L T say Lysis cycle Lysogenic cycle In short, during the lytic cycle, aimP expresses the amino acids and it is secreted out. The amino acid enters another host cell, eventually causing the new host cell to inactivate the gene for starting the lytic cycle, which leads to the activation of lysogeny II. Bread making (2011 iGEM Johns Hopkins) A You know that yeast produces carbon • vitamin dioxide during respiration to help raise the 1- bread dough. And in fact we could Secret engineered bacteria to allow it to produce more nutrients to our bread! iGEM team Yeast from Johns Hopkins try to insert genes that codes for enzymes that are essential in the biochemical pathway of producing Secret Vitamin A and Vitamin C in a way to t . solve Vitamin A deficiency in undeveloped C countries! • Vitamin III. Sewage eament (2018 iGEM SHSBNU China) Q. Now you know how microorganisms aid in sewage treatment, and it seems it is effective dealing with larger, solid waste, but have you thought of how synthetic dye are treated inside the waste stream??? There are 3 existing solutions, physiochemical method, photocatalytic method and microbiological method. However, these methods are either sophisticated or inefficient. Therefore, an iGEM team in 2018 try to solve this problem by using-----Biofilm. Biofilm is a slimy layer produced by bacteria on the surface to protect itself and its enzymes on the surface at a wide range pH environment Biofilm iEBtEgEBacteria Biofilm and spy CotA Lactase + ÷÷÷EaaaaaaCatcher By using genes that codes for SpyCatch and SpyTag (SpyCatch will catch SpyTag, just like the name suggests) and a gene that codes for laccase (an enzyme that decolourises dye). They try to connect bacterial biofilm using SpyCatch and SpyTag with laccase on it. In this way they could create a large sheet of biofilm with enzymes that could decolorize dye inside the sewage system.