Thursday, April 7, 2011

IB Microbes and Biotechnology Option F

Nitrogen Cycle and Microbes involved........


Picture taken from
http://bettersoils.soilwater.com.au/module2/images/27.gif
Bacteria involved in Nitrogen cycle are in words below


Picture taken from
http://www.finnslough.com/Environment%20Pages/nitrogen_cycle.htm


Bacteria Involved in Nitrogen Cycle 
picture from
http://www.splammo.net/bact102/102exp091011.html
Keywords are 
Nitrogen Fixation, Nitrification, Denitrification, Ammonification, Nitrites, Nitrates, 
Microbes Involved

  • Nitrogen Fixing bacteria, Azotobacter and Rhizobium ( mutualistically ) in root nodules in legume plts Convert Nitrogen to Ammonia
  • Nitrifying Bacteria, Nitrosomonas and Nitrobacter (aeration) needed. Nitrosomonas convert Ammonia to Nitrites, Nitrobacter convert Nitrites to Nitrates
  • Denitrifying Bacteria, Pseudomonas ( anaerobic ) convert Nitrates to Nitrogen
............................................................................................................
Quorum Sensing by Vibrio Fischer and Bobtail squids....
Keywords are 
Symbiosis, Autoinducers, Quorum Sensing, Bioluminescence, Aggregates, Quorum quenching


TEDTALK on Bacteria Communication using Quorum Sensing


Quorum Sensing
Quorum Sensing was observed in Vibrio fischeri, a bioluminiscent bacterium that lives as a mutualistic symbiont in Hawaiian bobtail squid.
Bacteria used it to coordinate behavior/control their population density by producing signalling molecules known as autoinducers which are used to regulate gene expression.
How it works!
Squid has a built-in flashlight uses bacteria to help navigate night waters, hunt for prey, and hide from predators. A little cavity on squid's underside houses colonies of bacteria known as Vibrio fischeri.
Cilia sweep bacteria from water into the cavity, once the colony reaches critical density population it produces autoinducers which acts as communication tool that control gene regulation to release an bioluminescent enzyme called luciferase leading to bioluminescence.

Mutual Beneficial Symbiotic Relationship ( Endosymbiotic )


How Bacteria Benefit from Squid?

Squid feed the bacteria with amino acids and nutrients.
How Squid Benefit from Bacteria?
At Night, squid uses bacteria light to hide its silhouette/shadow whereby bacteria able to produce enough light from the bottom (bio flashlight) to match the amount of light striking the top. (antipredator devise).

During Day, squid releases the bacteria into water and as conc of bacteria drop, conc of autoinducers drop, and it stop producing light. As day progresses, bacteria conc increases, conc autoinducers increase, and light will be produced again.


How Quorum Sensing Works
  • Bacteria population increases and start to release autoinducers
  • Autoinducers will bind to specific receptors and induce the release of enzyme luciferase
  • Enzyme luciferase will cause bioluminescence
  • Bacteria population drops, autoinducers will drops and light will not be produced.
  • Production of autoinducers/bioluminescence is dependent on population density of bacteria
  • Bacteria Communicate/Talk with each other

Bioluminesence by Vibrio Fischeri........................


Click HERE for more videos on how bacteria communicate using secreted chemical signals molecules called autoinducers. 
Keywords from TedTalk are
  • Bacteria Communication using Quorum Sensing
  • Bacteria acts collectively using intramolecular/ intermolecular signals called autoinducers
  • Once reaches a population density, chemical signals will be released and bacteria will attack
  • Cell to cell communication signal is used to regulate production of virulence factors/biofilms
  • Develop anti-quorum sensing agent to block bacteria communication or block production of virulence factors
  • Anti-Quorum Sensing drugs as replacement for Antibiotics( most bacteria are resistant against antibiotics now)
"Latest New Discovery News on 16 May 2011
NASA's Endeavour space shuttle will be carrying a peculiar live cargo: a creature named, Hawaiian Bobtail Squid to study the effect of microgravity environment on the squid's ability to be colonized by the bacteria. It is important as our body is also colonised by 90 trillion and 500 different species of bacteria
..................................................................................................................................................... 
Gene Therapy, altering the genotype....Somatic or Germline 
Gene therapy using Adenovirus for SCID treatment
Click HERE to get into Animation for SCID
What is ADA deficiency, SCID, T Cell, Purines, Immunity
Click HERE to find out...........
Gene therapy in Powerpoint Presentation.......
Risk of gene therapy are ......
Short lived, Immune Response, Problems with Viral vectors, Multigene disorder, Inducing a Tumor
..........................................................................................................................................................
6 Methods on how pathogens are Transmitted.
Key words
Contact, Vector/ insect, Food and Water, Airborne, Sexual Contact, Droplets, Wounds

......................................................................................................................................................
Distinguish between extracellular and intracellular infection....
Keywords for Extracellular infection are......
Infection outside cell, virulence factors/proteins, opsonins, Gram positive, Streptococcus, sphere....
Picture taken from CDC.....
Keywords for Intracellular are....
Infection inside cell, multiply in host cells, reticulate bodies, endocytosis, Gram negative, Chlamydia

Distinguish between Exotoxins and Endotoxins.
Exotoxins secreted destroys connective tissues, enzymes,  puncture/perforates holes on cell ....
Tetanus, Gram positive Clostridium Tetani, Nervous system, Muscle spasm, Neurotoxin, Lock jaw
Endotoxins  is lipopolysaccharide on the membrane surface of Gram negative bacteria, Salmonella
Endoxins causes symptoms are diarrheafevernauseavomiting, stomach cramps
Differences between Endotoxins Vs Exotoxin
   Endotoxin                                                                    Exotoxin
Toxin on cell membrane (LPS)                                   Toxin a protein that is released
Less toxic and is localised                                         Toxic in minute amount and spreads
Released from cell during cell lysis                           Secreted from live cell and attack specific cell
Toxin stable, cause inflammation/fever/diarrhea     Toxin unstable and denatured by heat
Gram negative like Salmonella, E Coli, Shigella     Gram positive like Streptococcus,                       
                                                                                  Clostridium Tetani/ Botulinum (Neurotoxin)
                                                                                     
Picture taken from AAIM
http://allaboutim.webs.com/apps/blog/show/6238249-enteric-fever
.............................................................................................................................................................
Microbial growth control by
Irradiation, Pasturization, Antiseptics, Disinfectants
Keywords .........
Phenol, chlorhexidine, hypochlorite, bacteriocidal, bacteriostatic, gamma ray, sterilise, 72/15s
Action of Antibiotics...............
Keywords............
Inhibits.....cell wall synthesis by penicillin, vancomycin and cephalosporin
Inhibits....protein/ribosomes for protein synthesis by erythromycin, streptomycin, tetramycin
Inhibits...nucleic acids/RNA polymerase  by rifampin, anthracyline


Cell wall inhibition on peptidoglycans..........


Ribosomes Inhibition by Macrolides/Erythromycin/Streptomycin
Bacteria ribosomes are 30/50S while humans are 40/60S


Antibiotics Resistance....................




Epidemiology is the Spread of disease, Factors Influencing Its Spread and How to control
Rabies............................................Rhabdo (Virus)........................zoonosis dog and animal bites
Ebola...........................................Ebolavirus( Virus )....................suspect bats, monkey
Flu Virus


Zoom it in to view Flu Virus



Click HERE to get into Infographics for diseases........
Asian Flu (1957)........................ H2N2 ( Virus )
SARS  (2004 )...............................H1N1 ( Virus )
Swine Flu (2009) Mexico ...........H1N1 ( Virus)

Pandemic vs Epidemic


Epidemic is localised in a region or country while Pandemic is widely spread to many countries
Worst Pandemic 


Bubonic Plague 1350  by Yersinia pestsis ( Bacteria ) in fleas on rats
75 million death.................................





Spanish Flu 1918 by H1N1 Virus
20 to 50 million death.............


Method to control Epidemic or Pandemic
Vaccination...1st disease to be eradicated  is smallpox in 1980 using cowpox.
Thanks to Eward Jenner ( Father of Immunology)

Discuss the origin and epidemilogy of a named example of a pandemic.
Keywords..............
Define pandemic, Give an example, Caused by, How is it spread, Cross species from animal to Human, Mutation of new strain from H1N1 to H2N2 to H5N1, Mode of Transmission, Why it spreads so fast, Symptom, Heath measure to control, Vaccination, Restrict travel, Quarantine, Medical, Antiviral drugs against it.

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