Lecture 1B- Classification Dr. Souki General Microbiology East Los Angeles College

What are microbes (microorganisms)? Cells and infectious agents too small to be seen with the naked eye – < 0.2 mm (= 200  m) Examples include: – Bacteria (Escherichia coli, Salmonella) – Archaea Extremophiles – Methanogens – Halophiles (salt lovers) – Thermophiles (heat lovers) – Protozoa – Fungi – Viruses (Human Immunodeficiency Virus [HIV]) – Viroids – Prions Microbiology Escherichia coli Thermophiles Halophiles Methanogens Protozoa Yeast

Where are microbes? Ubiquitous Normal flora – Staphylococcus epidermidis skin – Escherichia coli Colon – Bacteriodes sp. Small intestine Pathogenic bacteria – Helicobacter pylori – Methicillin-resistant Staphylococcus aureus (MRSA) Nosocomial

What other diseases are caused by microorganisms? Influenza Septicemia Respiratory infections HIV/AIDS – Virus Diarrhea – Bacterial Salmonella sp. E. coli Shigella sp. – Viral Rotavirus Norovirus Tuberculosis – Mycobacerium tuberculi

How is microbiology applied? Food Production – GMOs Commercial Products – Antibiotics & vaccines Bioremediation – Microbes used to degrade organic wastes Genetic Engineering – Microbes engineered to produce new compounds – Recombinant DNA technology Ex: Insulin, Vaccines

How is microbiology applied? Bacteria - Lactobacillus species and others yeast Saccharomyces Various bacteria (Lactococci sp., Lactobacillus sp., Streptococcus sp. and/or yeast

1.What is a microbe? 2.List 7 types of microbes. 3.Contrast bacteria and prions. How are they different? 4.List 3 practical uses for microbes. Explain how each is useful to society.

How are living things classified? Common characteristics – Physical characteristics – Life cycles – Nutrient requirements – Biochemical processes – DNA similarities Mitochondrial DNA Chloroplast DNA Nuclear DNA Taxonomy - study of classification of species – Cladistics Links organisms to common ancestor

Classifying Living Organisms: The Three Domain System Developed by Carl Woese Based on 16S rRNA nucleotide sequence

How are organisms named? Binomial nomenclature Developed by Carolus Linnaeus ~ 1735 Each organism is given a genus and species name Example: Staphylococcus aureus – Genus names are like last names – Species names are like first names Where do names come from? – description of an organism / habitat / in honor of a researcher / misc. Always italicize or underline genus & species

Naming Microbes Example: Staphylococcus aureus Genus: Species:

1.What is a species? 2.Explain how cladistics helps scientists with taxonomic classification of various species. 3.Who is Carl Woese? 4.Who is Carolus Linnaeus? 5.What are the three domains? List major members of each domain.

What are prokaryotes & eukaryotes?

Domain - Bacteria Single-celled organisms Prokaryotic – lack nucleus Simple shapes – round, rod, spiral Cell walls - peptidoglycan

Domain - Archaea Single-celled organisms Prokaryotic – lack nucleus Cell wall WITHOUT peptidoglycan 3 main groups: 1.Methanogens 2.Extreme halophiles 3.Extreme thermophiles

What are eukaryotic microorganisms? Includes the kingdoms – Fungi – Protista – Animalia – Plantae

Kingdom Fungi Domain – Eukarya Kingdom Fungi Includes: 1.Yeasts – unicellular 2.Molds – multicellular 3.Mushrooms – multicellular Absorb nutrients from environment

Kingdom Protista Domain – Eukarya Kingdom Protista Unicellular organisms Eukaryotic – have nucleus Motility by: -- Cilia -- Flagella -- Pseudopodia Are free-living or parasitic Protozoa cause diseases: – Malaria – Giardiasis – Amoebic dysentery

Kingdom Animalia Phylum Platyhelminthes Domain – Eukarya Kingdom Animalia Phylum Platyhelminthes Flatworms – Liver flukes Cause fascioliasis – Fluke found in bile duct & liver Transmission: – Contaminated water – Eating vegetables washed/irrigated in contaminated water Raw watercress – Eating undercooked liver/snails

Kingdom Animalia Phylum Nematoda Domain – Eukarya Kingdom Animalia Phylum Nematoda Roundworms – For example: Ascaris Causes infections of GI tract Transmission: – Eggs leaves body in feces – Ingestion food contaminated with dirt containing eggs Diagnosis: – Eggs in stool – Cough up worm Graphic Content

Kingdom Animalia Phylum Annelida Domain – Eukarya Kingdom Animalia Phylum Annelida Segmented worms – Leech Blood suckers Hirudo medicinalis – Used in early (1800s) blood- letting treatments Hirudin anticoagulant – Currently used in limited procedures Graphic Content

Viruses Non-living Infectious Agents - Viruses Require host cell for reproduction Obligate intracellular parasites Simple structures: – Nucleic acid DNA or RNA Capsid – Protein coat Envelope NO ORGANELLES Ebola Influenza

Viroid Non-living Infectious Agents - Viroid Require host cell for reproduction Obligate intracellular parasites Simple structures: -- RNA only Plant parasites Hep D in humans

Prions Non-living Infectious Agents - Prions Protein in misfolded form For example: – Bovine spongiform encephalitis (BSE) – Creutzfeldt-jakob disease Misfolded protein causes other proteins to become misfolded Results in neurodegeneration

1.What is an organelle? 2.Define prokaryote and eukaryote. 3.Which 2 domains are prokaryotic? 4.List various eukaryotes. 5.Are virus, viroids, and prions considered living? Explain why or why not. 6.What are the three main groups of archaea? 7.List 3 helminth phyla. Which are pathogenic? 8.What are protozoa?