Mikrobiologi

• Robert Hooke


  first to observe "small chambers" in cork and call them cells.
• Antonj Philips van Leeuwenhoek


  father of microbiology. Used microscope to make their first observations of microbes
• Ferdinand Julius Cohn


  Established sterile techniques and systematic classification of bacteria. Founder of a journal which published most of the early bacteriology papers
• Louis pasteur


  saw that yeast was the source of fermentation that turned grape → wine

  also founder of the swan-necked flask experiment
• Robert Heinrich Hermann Koch


  father of medical microbiology

  Koch's postulates: system for linking certain microbes to diseases as causative.

  Also various microbiological tools were developed in Koch's lab including Petri dish and agar based solid media
• Sergei Nikolaievich Winogradsky


  Advanced our understanding of microbes in the environment and the critical roles they play in nutrient cycles of our planet
• Martinus Willem Beijerinck


  Enrichment culture techniques that help isolate and study specific microorganisms
• Koch's postulates are a set of criteria used to establish a casual relationship between a microorganism and a disease:


  1. microorganism must be found in all organisms suffering from the disease but should not be found In healthy organism

  2.. The microorganism must be isolated from a diseased organism and grown in pure culture

  3. The cultured microorganism must cause disease when introduced into a healthy organism
• Swan-necked flask experiment


  spontaneous generation of life do not occur. The neck prevented dust and microbes from reaching the broth in the flask --> life only arises from pre-existing life
• Robert Hooke


  first to observe "small chambers" in cork and call them cells.
• What is an organic molecule?


  contain C-C and/or C-H bonds
• ex Non organic molecules:


  diamond, graphite, carbon nanotubes

  carbonic acid

  hydrogen cyanide
• ex Organic molecules:


  carbon tetrafluoride

  mesoxalic acid
• GOE, what is it?

  great oxygenation event. It was a gradual process when the earth's ocean was saturated (mättad) with dissolved Fe2+
• explain why the ocean became saturated and what happened next:

  Fe needs to be soluble to be absorbed by cells.

  
  

  As soon as O2 was produced by cyanobacteria it reacted with Fe2+ to produce Fe2O3 (hematite) and Fe3O4 (magnetite)

  
  

  both hematite and magnetite are very insoluble and therefor sinks to the bottom of the ocean
• Eutrophication: freshwater and seawater ecosystem


  a process when an aquatic ecosystem becomes richer with minerals or nutrients

  
  

  Freshwater ecosystem: excess phosphorus

  seawater ecosystem: excess nitrogen or N+P
• Nitrogen fixation:


  N2 to NH3
• Nitrification


  Nh3 to No3-
• Nitrate reduction


  NO3- -> NO2-
• Denitrification


  NO2- to N2
• adhesions

  common bacterial adhesion molecules
• three type of adhesions

  fimbriae, pili, polysaccharides
• fimbriae

  filamentous protein structures which help organisms to stick to surfaces
• pili, what does it assist in?

  filamenotus protein structures, longer than fimbriae.

  
  

  Some types of pili assist in surface attachment.

  
  

  Some facilitate genetic exchange between cells

  
  

  Type IV is involved in a type of gliding mobility: this is called twitching motility
• polysaccharides and how do bacteria use it

  capsule/slime layers, biofilm matrix polysaccharides.

  
  

  Many bacteria produce and secrete polysaccharides to the outside of the cell, they are generally sticky molecules. Also, some polysaccharides create a thick layer around the cells
• what is biofilm matrix polysaccharides?

  biofilm is a community of bacteria grown attached to a surface

  
  

  surrounded by/imbedded into extracellular matrix polysaccharides
• lipoglycans


  lipoteichoic acids and LPS
• What do flagella assist in?

  microbial swimming mobility which rotates to provide a propeller-like locomotion with a helical shape
• 4 types of ring : a bacterial flagellum

  L ring

  P ring

  MS ring

  C ring
• what is a flagellum is powered by?

  PMF (proton motive force) approx. 1000 protons per rotation

  
  

  C ring

  MS ring

  Rod

  mot protein
• polar flagellar motility (fast): monotrichous

  1.reversible flagella: change direction without stopping

  
  

  2. unidirectional flagella: cell has to stop to reorient
• flagellar motility (slow): peritrichous


  bundled flagella becomes separated and then flagella get bundled again
• What is taxis? Describe 2 types.

  a movement in response to chemical or physical gradients. Bacteria move towards chemoattractants and away from chemorepellents
• Vertical gene transfer

  when cell division occurs
• Horizontal gene transfer

  DNA is transferred from one cell to another
• What are mobile genetic elements?

  segments of DNA capable of moving within a genome or between different genomes

  
  

  such as:

  Transposons

  Plasmids

  Lysogenic bacteriophage
• what is Transformation:

  DNA is directly taken up by the cell from the extracellular environment such as:

  
  

  - DNA from lysed cell

  - Externally added DNA in laboratory condition

  - Environmental "free" DNA
• we can thank.... for observation

  Frederick Griffith's observation from how genetic materials can be passed from one cell to another
• explain Frederick Griffith's experiment:

  Frederick Griffith's experiment with Streptococcus pneumoniae revealed the phenomenon of bacterial transformation. He observed that mixing heat-killed virulent S strain bacteria with non-virulent R strain bacteria resulted in becoming virulent. This suggested the transfer of genetic material between strains. Although Griffith didn't grasp the molecular nature of this process, his work laid the groundwork for later discoveries about DNA's role as the hereditary material and bacterial transformation.
• Competence: ability of a cell to take up extracellular DNA by transformation


  naturally competent bacteria: only some organisms