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. 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. Eukaryotes have both membrane bound nuclei and organelles. They have DNA that are formed into chromosomes. Some reproduce through fission but most reproduce sexually.

Typical Prokaryotic Cell

Typical Eukaryotic Cell

Nomenclature “Living” Organisms have both a common and a scientific name “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. 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. 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. Virus only have common names as they are not considered “living” organisms.

Examples of Prokaryotes Borrelia Ehrlichia Staphylococcus

Morphology of Bacteria Coccus or Round

More Shapes Bacilli or Rods

Spirochete

Gram-Negative vs. Gram Positive Bacteria An easy way to categorize An easy way to categorize 2 “types” of bacteria. 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. 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? So, what good is this?

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

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

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

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

Functions of Virus Pathogens Pathogens Can be the cause of certain cancers Can be the cause of certain cancers Utilized in research- may be used to cure diseases through gene therapy Utilized in research- may be used to cure diseases through gene therapy ab_bio/simulacions/GeneTherapy/GeneTh erapy.htm ab_bio/simulacions/GeneTherapy/GeneTh erapy.htm ab_bio/simulacions/GeneTherapy/GeneTh erapy.htm ab_bio/simulacions/GeneTherapy/GeneTh erapy.htm

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

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

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

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. 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. There is only 1 ciliate spp. Pathogenic to humans.

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

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