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Microbes and Society

Microbes and Society. Brief Introduction to Microbes. Prokaryotes vs. Eukaryotes. Prokaryotes have no membrane bound nucleus or organelles. They have a single closed loop of DNA. Most of the prokaryotes reproduce by fission.

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Microbes and Society

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  1. Microbes and Society Brief Introduction to Microbes

  2. Prokaryotes vs. Eukaryotes • Prokaryotes have no membrane bound nucleus or organelles. They have a single closed loop of DNA. Most of the prokaryotes reproduce by fission. • Eukaryotes have both membrane bound nuclei and organelles. They have DNA that are formed into chromosomes. Some reproduce through fission but most reproduce sexually.

  3. Typical Prokaryotic Cell

  4. Typical Eukaryotic Cell

  5. Nomenclature • “Living” Organisms have both a common and a scientific name • Genus name is always capitalized while species name is not. Both are italicized or underlined. • For example, the black-legged tick (common name) has a scientific name of Ixodes scapularis. • Virus only have common names as they are not considered “living” organisms.

  6. Examples of Prokaryotes Borrelia Ehrlichia Staphylococcus

  7. Morphology of Bacteria Coccus or Round

  8. More Shapes Bacilli or Rods

  9. Spirochete

  10. Gram-Negative vs. Gram Positive Bacteria • An easy way to categorize 2 “types” of bacteria. • Dye bacteria using crystal violet and iodine. Gram-positives “soak” up the purple dye, gram negatives don’t. Then rinse in alcohol and counter stain with safranin. Gram-negatives stain orange-red while gram-positives stay purple. • So, what good is this?

  11. Functions of Bacteria • Commensals • Photosynthesis • Nitrogen fixation • Pathogens • Medicine (Recombinant) • Research • Others!!!!

  12. Types of Virus • They are simple, very small, and utilize others for help in reproduction. • Shapes include: • Helical, e.g. bacteriophage M13 • Polyhedral/cubic, e.g. poliovirus • Enveloped - may have poyhedral (e.g. herpes simplex) or helical (e.g. influenzavirus) capsids • Complex, e.g. poxviruses

  13. Other way to categorize Virus using nucleic acid • Some virus have double stranded DNA (like us) • Others have single stranded RNA (for example HIV)

  14. Viral Replication • There are 5 major steps in the replication cycle of all viruses: • Attachment • Penetration • Nucleic acid and protein synthesis • Assembly of virions • Release/egress

  15. Functions of Virus • Pathogens • Can be the cause of certain cancers • Utilized in research- may be used to cure diseases through gene therapy • http://www.edu365.cat/aulanet/comsoc/Lab_bio/simulacions/GeneTherapy/GeneTherapy.htm

  16. Protists • Eukaryotic, these include protozoa, certain types of algae and a few others • Four types of protozoans • Amoebas • Flagellates • Ciliates • Apicomplexans.

  17. Amoebas • They can change their shape and move by sending out pseudopodia. Water-borne amoebas cause amoebic dysentery.

  18. Flagellates • Move using flagella, this group causes diseases such as African sleeping sickness, common venereal disease- Trichimonas, and Giardia (or beaver fever) Trichomonad of cattle

  19. Ciliates • Tiny hairlike projections all over the surface beat in networks along the cell which allows the organisms to move forward, backwards and rotate. They are also capable of sexual recombination. • There is only 1 ciliate spp. Pathogenic to humans.

  20. Apicomplexans • Many are intracellular in parts of their life cycle, they have organelles that allows them to gain access into cells. • Malaria-up to 2 million/year die • Toxoplasma- dangerous for immunocompromised/preganant women • Pneumocystis carinii- one of the leading causes of death in AIDS patients

  21. Fungi • Yeasts- lots of positive uses including fermentation that leads to bread rising, and alcohol production. • Some yeasts can cause infection (thrush or yeast infections) • Molds- Decomposers that are sometimes compacted together known as a mushroom • Lichens-part fungus part other (cyanobacteria) • Ringworm

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