Introduction to Microbiology student notes

Microbiology

The study of microscopic organisms

“Microbiology” Root words

(micro = small, + bios = life, + logos = word/study)

Prokaryotes’ root words

(pro = before, + karyo/karyon = kernel = nucleus)

Prokaryote domains

Archaea, Bacteria, Monera (abolished)

Prokaryotes’ characteristics:

unicellular organisms; lack subcellular structures such as membrane-bound nuclei or organelles (mitochondria, chloroplasts); the simplest living organisms

What are the two main groups of Prokaryotes?

Bacteria (eubacteria/D. Bacteria), and Archaea (D. Archaea)

What are the characteristics of Eubacteria (True/good bacteria)

very small, unicellular, prokaryotic; most have cell wall that contains a very large polymer compound called peptidoglycan

What is Cyanobacteria and its characteristics?

Eubacteria; Blue-green algae; photosynthetic; either free-living or symbiotic found mostly in aquatic habitats; some nitrogen-fixers; no known pathogens

What are examples of Eubacteria pathogens?

Staphylococcus aureus, Clostridium Difficile, Escherichia coli (E. Coli), Yersinia pestis (Black plague), Klebsiella pneumoniae (pneumonia), Mycobacterium tuberculosis

Archaea (archaebacteria = “ancient bacteria”) Characteristics:

Prokaryote; extremely small; cell walls lack peptidoglycan; they have other biochemical difference from bacteria; no known pathogens.

Eukaryote root words’ meaning, and domain

Eu = good/true + karyon = nucleus; Domain Eukarya

What were Protists formerly called? Are they eukaryotic?

Of Kingdom Protista; yes

What is an example of a plant-like protist?

Algae

Characteristics of Eukaryotes:

very diverse: microscopic, unicellular members, filamentous members, and colonial organisms; macroscopic seaweeds and kelps; all free-living and aquatic; photosynthetic.

What are some examples of eukaryotic protist pathogens?

Red Tide organisms, Prototheca, Pfiesteria piscicida

What are protozoa?

Animal-like protists

Characteristics of protozoa:

Unicellular, animal-like microbes (“animalcules”) = protozoa; move via flagellae, cilia, or pseudopodia (“false feet); mostly free-living and aquatic; some are soil microfauna

Examples of protozoan pathogens:

Plasmodium falciparum, Trypanosoma gondii, Giardia lamblia, Entamoeba histolytica

What are examples of Fungus-like protists?

water- and slime molds

example of the importance of water molds for plants:

Phytophthora infestans causes potato late blight, the cause of the Irish potato famine of the 1800s

What are the two main groups of Animal parasites - kingdom animalia:

helminths (worms) and arthropods (insects and arachnids)

What are examples of pathogens that are of the Kingdom Animalia?

taenia species (tapeworm); Necator americanus (hookworm)

Are arthropods directly pathogenic? what are they?

Aren’t usually pathogenic but are the carriers (=vectors) of a number of pathogenic microbes

examples of pathogenic microbes and their carriers:

Mosquitoes + malaria/west nile virus; ticks + lyme disease/rocky mountain spotted fever.

Scabies, mites, and lice cause disease by directly infesting animals/humans

Characteristics of viruses:

Crystallizable; acellular; very small (smallest = 30nm in diameter); virions = nucleic acid (RNA or DNA but not both) + protein shell = capsid; can be enveloped or unenveloped

Are obligate, intracellular parasites

Characteristics of Prions:

Infectious proteins; cause other similar proteins that are part of normal cells to become deformed

Fibrous masses = plaques; prions are obligate, intracellular parasites

Cause Transmissible Spongiform Encephalopathies (BSE = Mad Cow Disease; kuru = laughing sickness caused by eating human brains; Creutzfeldt-Jacob disease; Chronic Elk Wasting disease)