MCB 100 1st Edition Lecture 37Outline of Last Lecture I. Major groups of eukaryotic microorganisms a. Algaeb. Fungic. Protozoa (will cover next class) Outline of Current Lecture I. Topical fungal infections II. Fungal infections of the lungsIII. Protozoa IV. Examples of protozoa Current LectureI. Topical fungal infections1. Candida2. Athlete's foota. Dermatophytosisb. Caused by mold, most commonly trichophyton rubrum, trichophyton mentagrophytes, interdigitale, Epidermophyton floccosumc. These fungal species can cause "jock itch" and onychomycosis- fungal infection of the nails)d. Dermatophytes are contagious fungi2. Ringworma. Tinea corporis b. Caused by trichophyton rubrum, microsporum gypseum, and microsporum canis 4. Limited infections can be treated with topical antifungal agents while more widespread infections can be treated with orally administered terbinafine 5. Candida albicans a. A diploid fungus in phylum Ascomycotab. A commensal organism commonly found in the gut flora but can also be an opportunistic pathogenc. Thrush caused by an overabundance of candida in the moutha. Infection of oral cavityb. White patches on tongue c. Fungal infection of the upper respiratory tractThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.b. Candida is the most common opportunistic invader in diaper areas but diaper rash is mainly caused by irritation due to ammonia released from urine in presence of urease enzyme found in fecesc. Other invaders of diaper rash regions include- staphylococcus aureus, proteus mirabilis, enterococci, pseudomonas aeruginosa II. Fungal infections of the lungs1. Histoplasmosisa. Caused by dimorphic fungus Histoplasma capsulatumb. Found in soils contaminated by bat or bird droppings c. Contracted by inhalation of spores in dustd. Common sites to encounter this microorganism include: bat cave (Spelunker's disease) or a chicken coope. Infection is usually benign but may spread to disseminated form- raref. Symptoms mimic TB: fever, cough, chest pain, shortness of breathg. In severe cases- may cause lung cavities with tissue coughed up h. Treated with amphotercin B, ketoconazole 2. Coccidioidomycosisa. Valley fever, Desert rheumatism, San Jaquin Valley Feverb. Coccidioides immitis- a dimorphic fungus that grows as a mold in the soil and as a yeast in the human lungsc. Lives in soil in hot, dry, dusty areas (southwest) d. Typically encountered when a person inhales airborne sporese. Fungus invades lungs producing an inflammatory response, fever, cough, chest pain, loss of appetite, weight loss, and sometimes there is a hypersensitivity and rash f. Infection usually benign, but disseminated form may follow- spreading to the meninges, bones, joints, skin)g. Treatment- Amphotercin B and ketoconazole 2. Pneumocytosisa. Pneumocystis cariniib. More than 20,000 cases in 2000c. Associted with AIDSd. Behaves like protozoan, antgenically like a fungus, treat like bacterium (sulfonamide) 1. Pulmonary blastomycosisIII. Protozoa 1. Eukaryotic cells2. No cell wall3. Not photosynthetic4. Some absorb nutrient molecules by osmosis, others engulf food particles by phagocytosis5. Both sexual and asexual reproduction6. Most have mitochondria7. Most prefer aerobic conditions8. Size: 2-3 um (plasmodium merozoites) to 200-300 um (paramecia) 9. Motility: pseudopods, flagella, cilia10. Phagocytosis- engulfing food particles, digestion within vacuoles11. Encystment- cysts are a tough resting form of the organism12. Reproduction cycles can be asexual or sexual IV. Examples of protozoa: 1. Diplomonadsa. 2 nucleib. Flagellac. Thought to be very ancient lineage d. No mitochondria- some mitochondrial genes in the genomee. Trophozoite and cyst stagesf. Causes peristent diarrhea (giardiasis)g. Commonly affects wildlifeh. Found in creeks and ponds 2. Trichomonadsa. One nucleus b. Parabasal body- like a golgi apparatus c. Flagella, undulating membraned. Causes viginitise. Hydrogenosomes- energy-generating organelle, like mitochondria except they produce hydrogen and do not reduce oxygen f. No cyst stage- person to person transmission g. Ex. Trichomonas vaginalis 2. Amoeboflagellatesa. One nucleusb. Amorphous shaped cells c. One stage in life cycle has flagellad. Causes an uncommon form of meningitis, symptoms develop rapidly, affects brain e. Mitochondriaf. Three forms- amoeba, flagellated, cyst g. Ex. Naeglaria 2. Entamoebidsa. One nucleus b. E histolytica causes amoebic dysentery- fecal-oral cycle, cysts ingested- ingestion by human in contaminated food or water c. Most amoebas are free living and eat bacteriad. Most amoebas are motile using pseudopodse. Foraminifera have distinctive hard shells made of calcium carbonate or silicates- contribute to the formation of chalk deposits)f. Ex. Entamoeba histolytica and other amoebas 2. Ciliophoraa. Usually 2 nucleib. Most are free living c. Eat bacteria and algaed. Large- up to 300 ume. Cilia are short but numerous f. Macro nucleus- large, polyploid- multiple copies of genomeg. Micro nucleus- small, involved in sexual reproduction (DNA exchange) h. B coli can cause dysentery, usually in pigs i. Ex. Paramecium species, Balantidium coli 2. Trypanosomesa. Flagella, undulating membrane b. Have kinetoplasts- a form of mitochondria associated with flagella c. Blood diseases, transmitted by insects d. T brucei causes african sleeping sickness- transmitted by the tsetse fly e. T cruzii causes Chagas' disease- common in Bolivia2. Apicomplexaa. Contains some important human parasitesb. Most lack flagella ad cilia c. Complex life cycle with sexual stage d. Plasmodium species are transmitted by mosquitoes and cause malaria e. 4 different species of plasmodium cause 4 different types of malaria-like diseasef. Sporozoite stage derives from the zygote and is the infective form in humans g. Merozoite form invades and lyses human cells- especially red blood cellsh. Haploid gamet cells arise late in infection, gametes fuse to prduce a zygotei. Crystosporidium parvum is a water borne parasite in the apicomplexa family that causes diarrhea 2. Toxoplasma gondiia. Protozoa found in nearly all mammals and birds but is common in catsb. Animals shed oocysts in fecesc. Oocysts enter another host by way of the nose or mouth and the parasites colonize the intestinesd. Can also be transmitted by consumption of undercooked meat, blood transfusion,