What is microbiologyStudy of Micro-organisms: Organisms that EXIST as SingleCells 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 LIFE1. METABOLISM (nutrient uptake, biomass, waste output)

2. DIFFERENTIATION (Bacillus spp. Caulobacter)

3. REPRODUCTION (binary fission)

4. COMMUNICATION (Pseudomonas aeruginosa)

5. EVOLUTION (antibiotic resistance, pathogens)

Metabolism

Take in nutrients from the environmentglucose, lactose, other sugars, fats=lipids, proteins,toxic wastes, oils and petrol

Assimilate the nutrients into BIOMASSDNA, proteins, carbohydrates and complex carbohydrates, lipids

Release waste products into the environmentgases, alcohols, acids and organic compounds

Differentiation— to form distinct structures

Caulobacter spp. Vegetative cells versus stalk cells

K.C. Keiler M. Dworkin

Differentiation— to form distinct structures

Bacillus spp. endospore forming cellsAnabaena spp. Cyanobacteria forming heterocysts

T.J. Deveridge M. Dworkin

ReproductionTo 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.

J. Pitocchelli E. Hettema

Communicationinteraction with

other cells—response to other cells

Vibrio fischeri and Lantern fish

Kolter and Losick

AMNH--NYC

www.med.umich.edu

Genomenewsnetwork

Communication

Biofilms andHealth

EvolutionTo change ones genetic make up (DNA sequence) to

adapt to ones environment

Bacteria can take up DNA from the environment or other cells viaTransformation—uptake of naked DNA

Transduction—phage (bacterial specific virus) mediated uptake of DNA

Conjugation—uptake of DNA that requires the interaction of two bacteria

Antibiotic resistance, bacterial pathogenesis

What is microbiologyStudy of Micro-organisms: Organisms that EXIST as SingleCells or cell clusters and must be viewed individually with the aid of a Microscope

2. KEYWORD single CELLS (OR cell clusters)

CHARACTERISTICS THAT MICROORGANISMS HAVE THATMAKE THEM TRUE CELLS

1. CELL MEMBRANE –barrier that separates the inside of the cell from the outside

2. NUCLEUS OR NUCLEIOD – location of genetic information (DNA)

3. CYTOPLASM –location of the machinery for cell growth and function

4. MACROMOLECULES – proteins, nucleic acids, lipids, polysaccharides

3. KEYWORD exist as SINGLE cells (OR cell clusters)

We are multicellular creatures—made up of many cells

What makes one of our cells different from a microbial cell??

A single microbial cell can have an independent existence—ourspecialized cells need to interact with other cells in order to carry out their cellular functions for the good of the entire organism.

What organisms are considered to be microbial cells and studied in microbiology

1. BACTERIA2. FUNGI3. ALGAE4. PROTOZOA5. Viruses(although not a cellular entity but an

intracellular pathogen)6. Prions (a biochemical anomaly—misfolded proteins)7. Helminths Worms (multicellular)

TaxonomyThe study of phylogenetic relationships between organisms(The sorting of all living things based on their related or differentiating features)

KINDOM the highest level in classificationPHYLUM related classesCLASS related ordersORDER related familiesFAMILY related generaGENUS closely related speciesSPECIES organisms sharing a set of biological traits and reproducing only with their exact kind

Further classifications especially with bacteria:Strain—organisms within a species varying in a given qualityType—organisms within a species varying immunologically

Taxonomy::relatively easy to classify animals and plants based on their behaviour and appearance—old school

Taxonomy::initially 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 RNA—structural RNA of the ribosome that plays a role in protein synthesis)

Phylogenetic classification of micro-organisms (new school)

Universal Ancestor

AlgaeFungiProtozoa

ProkaryoticEubacteria Archaeabacteria

Eukaryotic

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

Major Differences between prokaryotic and eukaryotic micro-organisms

Prokaryotes1. Nonmembrane bound nucleiod region2. DNA-one circular molecule one chromosome3. Haploid-One copy of a gene4. Plasma membrane does not contain sterols5. Reproduction—simple binary

fission

Eukaryotes1. Membrane bound nucleus containing DNA2. DNA-linear molecules arranged to form several chromosomes3. Diploid-Two copies of a gene4. Plasma membrane contains

sterols5. Reproduction—meiosis and mitosis6. Presence of membrane bound

organelles such as chloroplasts and mitochondria

Why study Microbiology ??

Microbiology as a BASIC ScienceBacteria 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 ScienceMedicine—Vaccine development, production of antibiotics,production of important biological enzymes (insulin)Industry—Production of beer, wine, cheeses and yogurtAgriculture—maintenance of soil fertility/digestion in cattleEcology—Bioremediation—microorganisms that degrade toxic waste materials