AND Section1: DSE Bio Elective 3 Microorganisms and Humans Quick Review Oline: 1. 2. Use of Microorganisms 3. Microbial 4.Harmful Effects of Microorganisms ② ① Attachment I. Microbiology

② oo• cycle of a Penetration ¥14, ✓ "⑤ Release 1. Attachment The virus attaches itself to 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 to synthesise new viral DNA/RNA and 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 are exhausted, newly formed will lyse the host cell and spread to infect nearby cells ***Viruses are cell-type specific/ -specific ***Viruses without host cell will disintegrate rapidly ***Growth of viruses are different from other living things * Note (Latent ) Viral nucleic (DNA/ RNA) may be integrated into host cells DNA and replicated along with host cell’s DNA during cell During latent period, no new viruses are produced Viral are activated later oooo Growth of microorganisms * Growth requirement 1. Supply of source→ eg. Dead organic for 2. Supply of = source→ eg. Nitrogen for nitrogen fixing

3. Suitable and Suitable. pH - - → 4. Supply of- eg.aerobic respiration required for aerobic bacteria

5.Supply of -

* Stages of growth of microorganisms


Logarithm of living bacterial cells L . 1. Lag phase a. of bacterial cell b.Synthesis of and ATP 2. Exponential/ Log phase→ Max. growth a.Maximum growth rate under favourable conditions 3. Stationary phase→ growth rate= rate a.Depletion of b.Accumulation of toxic waste 4. Death phase→ growth rate

II. Use Microorganisms

Baa processing a. -/ -making/ -making

ORising Temperature - p q ( ) :ol Acti ve IT ' EH Anaerobic ORespiration ( I Source)

. o w. ¥ Stirring o¥i÷÷÷aRespiration ¥ - xMicrobes Killed # oHeating ⑨ b. Production of


Microbes Milk Killed

IT [Adding. Lactic ] ⇐ Thicken The Milk

Cool ¥ [Cooling] ⇐ ¥ Yogurt

••2. production ÷ ofE¥ → Antibody Microbes Fungi Bacteria t Nutrients

Q Extraction . ••2. production

' ' → → a ÷÷÷÷÷ Vaccine

••2.⑧ Industrial

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 of cells for extra fruit juice extraction

Pectin Pectinases Breakdown Catalyse In Cell Wall →

EH Juice •••2. treatment

•Factory & Household

Screening ¥FwSolids, Grits


Sludges . Fuel


Organic Substances

¥÷EDisinfection ET Pathogensw 2. production

Agricultural Industrial Food ••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 Genics

• Potential :

1. allergic response 2. Production of superbug 3. Transfer of GM genes to wild type IV. Hmful Effects of Microorganisms Toxins

a. Food poisoning→ caused by toxins produced by microorganisms .÷÷k÷. b. Food-borne → caused by pathogenic microorganisms present in food A.it#E*.E.E*E.EEE.a... o• Controlling growth of microorganisms

1. Physical method a. → avoid contact b. Heating→ kill microorganisms i. / 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. B. d. Drying→ dehydrate microbes to inhibit growth i.Natural-drying ii.Freeze-drying iii.Adding of large amount of / sugar e. Irradiation→ high to damage microbial DNA/ proteins 2. Chemical method a./ Antiseptics→ kill microorganisms b. → kill/ inhibit growth of microorganisms c. → slow down/ inhibit the growth of microorganisms d. Acids→ low pH to denature enzymes in microorganisms MICROORGANISMS AND HUMANS Section2: How is related in these Topics

Oline: 1. Phage Lytic Cycle 2. Bread Making 3. I. Phage lyric cycle (2018 iGEM Evry Paris-Saclay)

Q. What will happen if 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 to the host cell’s and are passed to the daughter cell. Therefore only lysing the daughter cell instead of the host cell. →→ In this way the could get a constant 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 secreted outside of the cell controlled by a 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 produces carbon • 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 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, waste, but have you of how synthetic dye are treated inside the waste stream???

There are 3 existing , 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 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 and spy CotA Lactase + ÷÷÷EaaaaaaCatcher By using genes that codes for SpyCatch and SpyTag (SpyCatch will catch SpyTag, just like the 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.