What is the definition of microbiology?
The study of microorganisms
-Are unicelluular (single cell), multicellular, or acellular (lacking cells)
Microorganisms are microscopic organisms
-Not visible to the naked or unaided eye
Why is microbiology important?
Terraform the planet by producing oxygen
-Photosynthetic bacteria
Backbone of the food chain
-Fix nitrogen required for plant growth
Cause disease (plant, animal and human)
Promote health
-Provides vitamins
Biotechnology and industries
-Produce vinegar and medication
What is the ancestral knowledge about microbes?
Traditional knowledge
-Oral tradition in Indigenous nations: 1993 Four Corners hantavirus outbreak, discovery of Rickettsia rickettsia (Rocky mountain spotted fever)
Traditional medicine
-Moldy bread to treat skin wounds
-Otzi “Iceman” used fungi with medical properties
Infrastructures
-Aquaducts for fresh water
-Sewage
Fermented food and beverages
Aquired immunity
What is the Miasma theory and spontaneous generation?
-Infectious disease were caused by bad air (miasma) emitted by rotting organic matter
-The theory of spontaneous generation: living organisms arise from non-living matter
-Prevalent ideas in Europe and some part of Africa and Asia
How was the field of microbiology started?
Robert Hooke
-Published a book called Microphagia
-Described fruiting structure of moulds
-First descriptions of microorganisms
-Existed during the fermentation of food and beverage, infrastructures and traditional medicine before the microscope
INVENTION OF THE MICROSCOPE (start the field of microbiology)
Antonie van Leeuwenhoek
-Simple microscope
-Observed and described bacteria
-“wee animalcules”
-Made advances in food microbiology, public health measures and modern pharmacology of infectious disease
Who were the important figures in the golden age of microbiology?
Louis Pasteur
-Fermentation: specific microbes (yeast), spoilage = unwanted microbes
-Pasteruization: kills bad microbes
-Vaccination
Robert Koch
-Established link between disease and microbes
-Laboratory techniques
(Microbial ecology)
Sergei Winogradsky:
-Microcosm and cross-feeding (Winogradsky columns)
Martinus Beijerinck:
-Identified nitrogen fixing
What are the types of microbes?
Cellular
-Prokaryotes: bacteria and archaea
-Eukaryotes: protists, fungi, and microanimals
Acellular microbes
-Viruses
-Prion
How do we classify microbes?
Two domains:
-Bacteria
-Archaea/Eukarya: Asgard (archaea) gave rise to eukarya
-Carl Woese compared 16S or 18S ribosomal RNA (rRNA sequence)
-viruses do not have rRNA
Three distinct lineage domains:
-Bacteria (prokaryotic)
-Archaea (prokaryotic)
-Eukarya (eukaryotic)
What are 70S or 80S rRNA?
How do we name cellular life?
-Domain (Bacteria/Eukarya/Archaea)
-Genus species (italicized), use short form once long form is used once. First name is genus (related) and second name is species (not related but similar cause)
What makes a microscope powerful?
Describe the Brightfield light microscope
Eye piece (ocular lens) and objective lenses are responsible for magnification
-Multiply together to obtain total magnification
-Used for bacteria but not smaller objects such as viruses due to lack of increased resolution with further magnification
What are the simple staining steps?
- Fixing the sample (place into fixative to preserve tissue and maintain life-like structure
- Add the stain (i.e. colour)
- Rinse the sample
What are the different simple staining methods?
Basic: positive stains for negative charged cell walls
-basic fuchsin
-Crystal violet
-Malachite green
-Methylene blue
-safranin
Acidic: negative stains repelled by negatively charged cell walls
-rose bengal, eosin, acid fuchsin
Describe differential staining
Explain the process of gram staining
Explain the process of acid-fast staining bacteria
Differentiates two types of gram-positive cells
Describe the darkfield light microscope
Does not require stains hence, high-contrast and high-resolution images for live specimens and motility
Describe the phast contrast light microscope
No stain = live specimens
-View cell structures such as eukaryotic organelles and prokaryotic endospores
Describe the fluorescence light microscope and its staining
Describe electron microscopy (EM)
TEM
-Uses electromagnets
SEM
-Electrons “bounce” on sample
-Give a 3D-like appearance
-Image of a surface
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