What is microbiology

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What is microbiology
Study of Micro-organisms Organisms that EXIST
as Single Cells or cell clusters and must be
viewed individually with the aid of a Microscope
1. EXIST (Webster definition)To continue to be,
have life live

• HALLMARKS OF LIFE
• METABOLISM (nutrient uptake, biomass, waste
  output)
• DIFFERENTIATION (Bacillus spp. Caulobacter)
• REPRODUCTION (binary fission)
• COMMUNICATION (Pseudomonas aeruginosa)
• EVOLUTION (antibiotic resistance, pathogens)

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Metabolism
Take in nutrients from the environment glucose,
lactose, other sugars, fatslipids,
proteins, toxic wastes, oils and
petrol Assimilate the nutrients into
BIOMASS DNA, proteins, carbohydrates and
complex carbohydrates, lipids Release waste
products into the environment gases, alcohols,
acids and organic compounds
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Differentiation to form distinct structures
Caulobacter spp. Vegetative cells versus stalk
cells
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Differentiation to form distinct structures
Bacillus spp. endospore forming cells Anabaena
spp. Cyanobacteria forming heterocysts
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Reproduction
To generate progeny of ones same type
A bacterium duplicates its DNA and forms a
daughter cell via binary fission Yeast
duplicates its DNA and forms a daughter cell via
budding, or mates with another yeast cell and
produces haploid progeny.
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Communicationinteraction withother
cellsresponse to other cellsVibrio fischeri and
Lantern fish
AMNH--NYC
Kolter and Losick
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CommunicationBiofilms andHealth
Genomenewsnetwork
www.med.umich.edu
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Evolution
To change ones genetic make up (DNA sequence) to
adapt to ones environment
Bacteria can take up DNA from the environment or
other cells via Transformationuptake of naked
DNA Transductionphage (bacterial specific
virus) mediated uptake of DNA
Conjugationuptake of DNA that requires the
interaction of two bacteria
Antibiotic resistance, bacterial pathogenesis
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What is microbiology
Study of Micro-organisms Organisms that EXIST
as Single Cells or cell clusters and must be
viewed individually with the aid of a Microscope
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2. KEYWORD single CELLS (OR cell clusters)
CHARACTERISTICS THAT MICROORGANISMS HAVE
THAT MAKE THEM TRUE CELLS

• CELL MEMBRANE barrier that separates the inside
  of the cell from the outside
• NUCLEUS OR NUCLEIOD location of genetic
  information (DNA)
• CYTOPLASM location of the machinery for cell
  growth and function
• MACROMOLECULES proteins, nucleic acids, lipids,
  polysaccharides

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3. KEYWORD exist as SINGLE cells (OR cell
clusters)
We are multicellular creaturesmade up of many
cells
What makes one of our cells different from a
microbial cell??
A single microbial cell can have an independent
existenceour specialized cells need to interact
with other cells in order to carry out their
cellular functions for the good of the entire
organism.
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What organisms are considered to be microbial
cells and studied in microbiology

• BACTERIA
• FUNGI
• ALGAE
• PROTOZOA
• Viruses(although not a cellular entity but an
• intracellular pathogen)
• Prions (a biochemical anomalymisfolded
  proteins)
• Helminths Worms (multicellular)

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Taxonomy
The study of phylogenetic relationships between
organisms (The sorting of all living things based
on their related or differentiating features)
KINDOM the highest level in classification PHYLUM
related classes CLASS related orders ORDER
related families FAMILY related
genera GENUS closely related species SPECIES
organisms sharing a set of biological traits and
reproducing only with their
exact kind
Further classifications especially with
bacteria Strainorganisms within a species
varying in a given quality Typeorganisms within
a species varying immunologically
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Taxonomyrelatively easy to classify animals and
plants based on their behaviour and
appearanceold school
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Taxonomyinitially not easy to classify
microorganisms based on their behaviour and
appearance
Advancements in DNA amplification and DNA
sequencing has greatly helped
The phylogenetic relationships between
microorganisms can be determined by sequencing
the 16S and 18S ribosomal RNA of the organisms in
question
(ribosomal RNAstructural RNA of the ribosome
that plays a role in protein synthesis)
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Phylogenetic classification of micro-organisms
(new school)
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Phylogenetic classification of micro-organisms
EUBACTERIA most abundant of the bacteria
found in soil, water and animal digestive tracts
ARCHAEACTERIA live in extreme conditions
(temperature, pH etc) mostly anaerobic (unable to
live in the presence of oxygen)
EUKARYOTES algae live in soil and water,
contains chlorophyll for
photosynthesis, has a cell wall
fungi yeast, molds. Lack
chlorophyll and obtains energy from
organic compounds in soil and water, has
a cell wall
protozoa colorless, lacks a cell wall,
ingests other organisms or organic particles
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Major Differences between prokaryotic and
eukaryotic micro-organisms

• Prokaryotes
• 1. Nonmembrane bound
• nucleiod region
• DNA-one circular molecule
• one chromosome
• Haploid-One copy of a gene
• Plasma membrane does not
• contain sterols
• Reproductionsimple binary
• fission

• Eukaryotes
• 1. Membrane bound nucleus
• containing DNA
• DNA-linear molecules arranged
• to form several chromosomes
• Diploid-Two copies of a gene
• Plasma membrane contains
• sterols
• Reproductionmeiosis and
• mitosis
• Presence of membrane bound
• organelles such as chloroplasts
• and mitochondria

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Why study Microbiology ??
Microbiology as a BASIC Science Bacteria and
yeast are useful in studying molecular biology,
biochemistry and genetics --reproduce
rapidly --are genetically (DNA) and
biochemically more simple than higher order
organisms --working with bacteria and yeast for
understanding life processes has no ethical
ramifications
Microbiology as an APPLIED Science MedicineVacci
ne development, production of antibiotics, produc
tion of important biological enzymes
(insulin) IndustryProduction of beer, wine,
cheeses and yogurt Agriculturemaintenance of
soil fertility/digestion in cattle EcologyBiorem
ediationmicroorganisms that degrade toxic
waste materials