Biology 331Eukaryotic Microbes

Eukaryotic Groups With Microbes

Algae - many chlorophylls, few pathogens

Fungi - structure groups, many pathogens

Protozoa - motility groups, many pathogens

Fig. 2.32, rRNA

Fig. 18.12, many genes/proteins

Mycology - More About Fungi

Fungi Features

Nearly all have chitin (NAG only) walls and…

Membrane ergosterols - antifungal drug target

Most differentiate - unicellular, hyphae, spores

Chemotroph decomposers - soil, water

Will NOT tackle book classification - too in flux!

X

Pathogenic Fungi

Mycoses grouped by depth - skip subcutaneous

Superficial = e.g. Trichophyton - athlete’s foot

Systemic = e.g. Candida - thrush, vaginitis

More About Protozoa

Protozoa Features

Unicellular, vegetative forms lack cell walls

Predatory chemotrophs, some make hardy cysts

Phenotypic Classification - motility groups…

DNA - new vs. old flagellates (no mitochondria)

Antiprotozoal drugs - agent/disease-specific, major side effects, resistance issues

Old Flagellate - Giardia lamblia

Cysts - mammal GI, 97% freshwater, resists Cl

2-4 weeks - foul, greasy stool, sulfuric gas

Can become chronic in liver - cyclic diarrhea

90% infants/oral-fecal; 30% gay men/STD

30% developing – carry or have Ab/exposure

Drug: Flagyl inhibits e- carriers

Old Flagellate - Trichomonas vaginalis

Hydrogenosome - novel anaerobic organelles

No survival outside host - STD or perinatal

Females: vaginitis, yellow/foul discharge, pain

Males: asymptomatic carriers

Drugs: Flagyl; condoms = effective control

This is NOT a notifiable disease - even though it likely causes 3 million US cases/year.

New Flagellate - Trypanosoma brucei

No survival outside host - insect-borne

African Sleeping - Tsetse Fly/Glossina saliva…

Fatal (0.5-2 yrs) – heart and/or CNS failure

Drug: Suramin halts metabolic enzymes

20,000 Africans die/year vs. 24 tourist deaths in 40 years (of 20,000 tourists to Africa/year).

New Flagellate - Trypanosoma cruzi

No survival outside host - insect-borne

Chagas - assassin/kissing bugs GI/feces

Mild flu-like to chronic heart/GI/CSF

Latin America: 16-18 million, 10% heart defects

Drug: Nifurtimox alkylates DNA

Disturbingly, US blood is not screened and this is not a notifiable disease.

Amoeba - Naegleria fowleri

Cysts - free-living in soil, water, hot springs

Nose to brain - hemorrhagic encephalitis

Fast frontal headache, taste/smell loss, seizure

Death in days, 4 survivors/140 cases worldwide

Drug: Amphotericin B attacks membranes

Sporozoa - Plasmodium

No survival outside host - insect-borne

Tropical Anopheles bite to liver (1 hour) to RBC

Sickle cell carriers PROTECTED

Acute Malaria: fever, headache, anemia

Drug: Quinolones/Quinine binds DNA

US/DDT eradicated in 1950’s but re-emerging = 2000 cases/year, most airport-associated