The Microbial World and You

The Microbial World and You

 Microorganisms  too small to be seen with unaided eye  “Germ”  rapidly growing cell

What are microbes?

 Fungi (molds, yeasts)  mycology  Protozoa  parasitology  Microscopic algae  phycology

What do they do?

      Decompose  organic waste Producers in the ecosystem  by photosynthesis Produce industrial chemicals  Ethanol and acetone Produce fermented foods  vinegar, cheese, and bread Produce manufacturing products  (e.g., cellulase) and treatment (e.g., insulin) A few are pathogenic,  disease-causing

Microbes everywhere on your body Microbes— Lactobacillius acidophilus —make yogurt Others make beer and wine— Saccharaomyces cereviceae

The better question might be, “what don’t they do?”

 Allows humans to  Prevent food spoilage  Prevent disease occurrence  Led to aseptic techniques to prevent contamination in medicine and in microbiology laboratories

Did you know?

    Bacteria causes body odor Bacteria, tiny as they are, can get sick, too!

Under the right conditions a bacterium like Escherichia coli can grow from just one cell to 1 million cells in less than 7 hours!

How their size compares?

How are microbes named and classified?

 Linnaeus established  system of scientific nomenclature.

 Each organism has two names:  genus and specific epithet.

 Are italicized or underlined. The genus is capitalized and the specific epithet is lower case.

 Are “Latinized” and used worldwide.

 May be descriptive or honor a scientist.

Scientific Names



Staphylococcus aureus

 Describes the clustered arrangement of the cells (staphylo-) and the golden color of the colonies (aur-).



Escherichia coli

 Honors the discoverer, Theodor Escherich, and describes the bacterium’s habitat–the large intestine or colon

Taxonomy

What is systematics?

 Study of phylogenetic relationships  Phylogenetics = ________  Taxonomy = __________  Also a way of organizing/ classifying  Taxa (taxon— singular)

Look at the background!

     Plant and Animal Kingdoms Bacteria and fungi  put in the Plant Kingdom Kingdom Protista proposed  for bacteria, protozoa, algae, and fungi

Prokaryote

introduced for cells "without a nucleus“

Prokaryote

defined as cells in which nucleoplasm is    not surrounded by a nuclear membrane Kingdom Fungi Kingdom Prokaryotae proposed Two types of prokaryotic cells found

How are prokaryotes classified?

 Use Bergey’s Manual

of Systemic Bacteriology

 Divides prokaryotes into (based on rRNA sequences)  Bacteria  Archaea

Who is Carl Woese?

1978: created current classification scheme

 Three domains  Bacteria  Archaea  Eukarya  Protists  Fungi  Plants  Animals

What are the key differences between the three divisions?

Cell type Cell wall Organelles/ nucleus?

Sensitive to antibiotic?

Eukaryotes Prokaryotes Archaea

What is the taxonomy of organisms?

 Domain  Kingdom  Phylum  Class  Order  Family  Genus  Species

How are eukaryotes classified?

 Endosymbiotic theory  Numerous kingdoms, including  Protista  Fungi  Plantae  Animalia

What about viruses—How are they classified?

 Not included in three domains, which are _______ _______ and ______  Why not?

 Viral species: population of viruses with similar characteristics

How do I tell prokaryotes apart?

 Really difficult  Morphology is very similar!

B. anthracis B. japonicum

So how can we tell them apart?

 Lab techniques such as  Staining  Gram positive vs. Gram negative

So how can we tell them apart?

    Biochemical test  Different bacteria will grow on different types of media  Carbohydrates  Proteins Serology  Slide agglutination test  Look for clumping of bacteria with antiserum  Serotypes are strains with different antigens DNA fingerprinting rRNA sequencing

A closer look at the microbes

What are bacteria?

      Simple, single celled  ubiquitous Prokaryotes  DNA is not inside a membrane Come in different shapes  Coccus (cocci, plural)   Bacillus (bacilli, plural) Spiral (corkscrew, comma or curved) Peptidoglycan cell wall Binary fission Some have flagella

What are archaea?

 Also prokaryotes  Cells wall do not have peptidoglycan  Live in extreme conditions  Extreme halophiles  Hyperthermophiles  Methanogens  Not pathogenic Figure 4.5b

What are fungi?

    Eukaryotes  Have a true nucleus  More closely related to __________ wall of chitin Uni- and multicellular Includes  Molds  Mushrooms   Yeasts Slime molds  Sexual and asexual reproduction Figure 1.1b

What are protozoa?

 Eukaryotes  Absorb or ingest organic chemicals  May be motile via pseudopods, cilia, or flagella Figure 1.1c

What are algae?

 Eukaryotes  Cellulose cell walls  Use photosynthesis for energy  Produce molecular oxygen and organic compounds Figure 1.1d

What are viruses?

 Acellular  Consist of DNA or RNA core  Core is surrounded by a protein coat.

 Coat may be enclosed in a lipid envelope.

 Viruses are replicated only when they are in a living host cell.

Figure 1.1e

What are multicellular animal parasites?

 Eukaryote  Multicellular animals  Parasitic flatworms and round worms are called helminths.

 Microscopic stages in life cycles.

Figure 12.28a

Brief History of Microbiology

The First Observations

 Ancestors of bacteria were  first life on Earth.

 observed in 1673.

 1665, Robert Hooke reported  living things were composed of little boxes or cells.

 1858, Rudolf Virchow  cells arise from preexisting cells.

 Cell theory: All living things are composed of cells and come from preexisting cells.

How did we discover microbes?

   Before the microscope:  Spontaneous generation  “vital force” forms life.

Microscope

 Van Leeuwenhoeke, 1670s Louis Pasteur, 1861  Showed microorganisms are in the air  Refutes spontaneous generation with biogenesis  Used curved flask Conditions Results Nutrient broth placed in flask, Microbial growth heated, not sealed Nutrient broth placed in flask, No microbial growth heated, then sealed S

pontaneous generation or biogenesis?

       When was the golden age of microbiology?

1857-1914 Pasteurization  Developed after investigation of fermentation Demonstration of aseptic technique  microbes are responsible for fermentation.

Fermentation  conversion of sugar to alcohol to make beer and wine.

Microbial growth  responsible for spoilage of food.

Pasteur demonstrated  spoilage bacteria killed by heat Pasteruization  high heat for a short time.

The Germ Theory of Disease

 Joseph Lister, 1860s used a chemical disinfectant to prevent surgical wound infections  Germ theory of disease  Robert Koch, 1876, Germany   Bacillus anthracis causes anthrax provided the experimental steps  Vaccination  Edward Jenner, 1796   Small pox and cow pox Immunology

What about modern microbiology?

 1928: Alexander Fleming  first antibiotic.

 Penicillium fungus made  antibiotic, penicillin, that killed S. aureus.

 1940s: Penicillin was tested clinically and mass produced.

Figure 1.5

Some terms in microbiology

 Bacteriology is the study of bacteria.

 Mycology is the study of fungi.

 Parasitology is the study of protozoa and parasitic worms.

 Immunology is the study of immunity. Vaccines and interferons are being investigated to prevent and cure viral diseases  Virology is the study of viruses.

Some modern concepts

 Bioremediation  degrade organic matter in sewage.

 degrade or detoxify pollutants such as oil and mercury.

 Biological Insecticides  Biotechnology  Genetic engineering UN 2.1

What is normal microbiota?

 Normal microbiota prevent growth of pathogens.

 Normal microbiota produce growth factors such as folic acid and vitamin K.

 Resistance is the ability of the body to ward off disease.  Resistance factors include skin, stomach acid, and antimicrobial chemicals.

What are infectious diseases?

 When a pathogen overcomes the host’s resistance, disease results.

 Emerging infectious diseases (EID): New diseases and diseases increasing in incidence.

      West Nile Virus Bovine spongiform encephalopathy Ebola hemorrhagic fever Hantavirus AIDS Anthrax