Exploring Eukaryotic Microorganisms and Internal Cell Membranes

1. 2019 Chapter 12 Eukaryotic MicroorganismsAlgae FungiProtozoa

2. Major Groups of Eukaryotic Microorganisms Algae, Fungi, Protozoa

3. “Yeast” and “Mold” are not taxonomic terms. Rather the words describe the appearance of a fungus. Some species will grow like yeast under one set of conditions and like a mold under other conditions.

5. Internal Cell Membranes - Endoplasmic Reticulum - elaborate membrane network within the cytoplasm - continuous with both the cytoplasmic and nuclear membranes - increases surface area for excretion of proteins - increases surface area for membrane bound enzymes - many 80S ribosomes are attached to the E.R. (rough ER)

6. Internal Cell Membranes - Nuclear Membrane - separates transcription from translation - eukaryotic mRNAs are extensively modified after translation Eukaryotic genes are organized into pieces. Exons are gene parts that encode information for protein synthesis. Introns are “nonsense” sequences that interrupt eukaryotic genes. Both introns and exons are transcribed to make RNA. Introns are removed and exons are joined together (spliced). Eukaryotic mRNAs are polyadenylated on the 3’ end (poly- A tail). Eukaryotic mRNAs have modified bases added to the 5’ end (capping).

7. Internal Cell Membranes - Membrane Bound Organelles Mitochondria, Hydrogenosomes, Kinetoplasts and Chloroplasts Mitochondria - organelles of cellular aerobic respiration - ETC located in inner mitochondrial membrane - ATP synthase located in inner mitochondrial membrane - mitochondria make most of the ATP that is used in the cell (ETC pumps protons into space between inner and outer mitochondrial membranes, PMF is used to generate ATP by ATP synthase.) - respiratory poisons such as cyanide act by inhibiting the flow of electrons in the mitochondrial Electron Transport Chain. - dual membrane - mitochondria contain a small autonomous chromosome - mitochondria contain their own ribosomes - most eukaryotic cells including all plant and animal cells have mitochondria and depend on them for ATP production by aerobic respiration

8. The hydrogenosome is a membrane-enclosed organelle that is seen in some anaerobic eukaryotic microorganisms, including: Trichomonas, some ciliated protozoa and some fungi. Hydrogenosomes produce H2, acetate, CO2 and ATP. Hydrogenosomes may have evolved from mitochondria or they may be degenerate mitochondria. They often lack a mitochondrial genome and have no cristae.

9. A Kinetoplast is an independently replicating, disk-shaped mass of circular mitochondrial DNA molecules found inside a large mitochondrion. Kinetoplasts are associated with the basal body of a flagella and are seen only in protozoa of the class Kinetoplastea, which includes Trypanosomes and Leishmania. They may not be directly involved in motility Trypanosoma brucei, black bar = 10 micronssource: Wikipedia source: Mark Wiser, Tulane University

10. Chloroplasts - organelles of photosynthesis in plants and algae - dual membrane - chlorophylls and electron transfer chain of light harvesting apparatus are found in the thylakoid membranes - contain a small autonomous chromosome - contain their own 70S ribosomes Chloroplast Structurefrom: schools.look4.net.nz Chloroplasts Dividingfrom: www.msu.edu

11. Eukaryotic Cells – Internal Cellular Membranes and Membrane Bound Organelles Which one of the following options is the best description for hydrogenosomes? A. a membrane-bound compartment within a eukaryotic cell in which the chromosomes are located B. a variation of mitochondria seen in Trypanosomes and Euglenas that is associated with the basal body of a cluster of flagella, basically they are large mitochondria with a defined body that contains DNA C. a variation of mitochondria seen in anaerobic protozoa such as Trichomonas, the oxidation of NADH to NAD+ is coupled to hydrogen production rather than the reduction of oxygen to form water as is seen in aerobic respiration D. a membrane-bound organelle involved in photosynthesis

12. Eukaryotic Cells – Internal Cellular Membranes and Membrane Bound Organelles Which one of the following options is the best description for hydrogenosomes? A. a membrane-bound compartment within a eukaryotic cell in which the chromosomes are located (nucleus) B. a variation of mitochondria seen in Trypanosomes and Euglenas that is associated with the basal body of a cluster of flagella, basically they are large mitochondria with a defined body that contains DNA(kinetoplasts) C. a variation of mitochondria seen in anaerobic protozoa such as Trichomonas, the oxidation of NADH to NAD+ is coupled to hydrogen production rather than the reduction of oxygen to form water as is seen in aerobic respiration D. a membrane-bound organelle involved in photosynthesis (chloroplast)

13. Eukaryotic Cell Structure Which ONE of the following statements about eukaryotic microorganisms is FALSE? A. All eukaryotic cells have ribosomes of a size of 80S. B. Most eukaryotic cells have mitochondria but there are some protozoa that don’t. C. All photosynthetic eukaryotic microorganisms have cell walls that are made of cellulose. D. Eukaryotic chromosomes are linear and typically have several origins of replication. E. The vast majority of DNA in a typical eukaryotic cell is found in the nucleus but there is a small amount of DNA found in the mitochondria and chloroplasts.

14. Eukaryotic Cell Structure Which ONE of the following statements about eukaryotic microorganisms is FALSE? A. All eukaryotic cells have ribosomes of a size of 80S. B. Most eukaryotic cells have mitochondria but there are some protozoa that don’t. C. All photosynthetic eukaryotic microorganisms have cell walls that are made of cellulose. (Euglenas don’t) D. Eukaryotic chromosomes are linear and typically have several origins of replication. E. The vast majority of DNA in a typical eukaryotic cell is found in the nucleus but there is a small amount of DNA found in the mitochondria and chloroplasts.

15. Algae

16. Algae - Ecological Significance - common in water, and upper millimeters of damp soil and in snow - oxygenic photosynthesis - bottom of food chain - some are involved in symbiotic relationships with fungi (lichens)

18. Algae – Traits of the 6 major groups - Euglenophyta - euglena, no cell wall, thick flexible membrane called a pellicle, they have flagella (Kinetoplastids) - Chlorophyta - green algae, cell walls are cellulose, chlorophylls etc. are similar to plants (Plantae) - Chrysophyta - diatoms, cell walls often contain glass-like silicates, often golden-brown color (Stramenopila) (Heterokont) - Pyrrophyta - dinoflagellates, have two flagella, many produce toxins, cause “red tide” (a shell fish infection that can cause food poisoning) (Alveolates) - Rhodophyta - red algae, sea weed, source of agar and carrageenan (Rhodophyta) - Phaeophyta - brown algae, sea weed (Stramenopila)

19. Algae Which of the following descriptions is the best fit to the Rhodophyta?   A. Members of this group have cell walls that are made of glass-like silicates. B. Members of this group are found in the oceans and sometimes called red sea weed. Their cell walls often contain compounds like agar or carrageenan. C. Members of this group have cell walls, chloroplasts and photosynthetic pigments that are most like those of higher plants. D. These marine algae are more closely related to paramecia and malaria parasites than they are to the green algae. Some make red pigments & neurotoxin causing “red tide”. E. Members of this group don’t have cell walls but rather a thickened but flexible cytoplasmic membrane called a pellicle. They are motile by means of flagella.

20. Algae Which of the following descriptions is the best fit to the Rhodophyta?   A. Members of this group have cell walls that are made of glass-like silicates. (Diatoms) B. Members of this group are found in the oceans and sometimes called red sea weed. Their cell walls often contain compounds like agar or carrageenan. (Rhodophyta) C. Members of this group have cell walls, chloroplasts and photosynthetic pigments that are most like those of higher plants. (Chlorophyta) D. These marine algae are more closely related to paramecia and malaria parasites than they are to the green algae. Some make red pigments & neurotoxin causing “red tide”. (Dinoflagellates) E. Members of this group don’t have cell walls but rather a thickened but flexible cytoplasmic membrane called a pellicle. They are motile by means of flagella. (Euglenas)

21. Fungi Amanita Picture from: www.microbiologyonline.org.uk

22. Fungi Kingdom specific traits (myco-) - cell walls made of chitin (a polymer of n-acetylglucosamine) - cytoplasmic membranes contain ergosterol - about 100,000 species have been cataloged - most fungi survive by degrading dead plant matter, can digest lignocellulose - some fungi are significant plant pathogens - some fungi, especially plant pathogens, produce potent toxins - a few fungi are human pathogens - have mitochondria (yeast petite mutants lack them, but they don’t grow well) - most can reproduce either sexually or asexually (fungi imperfecta lack sex) - unicellular fungi = yeasts, multicellular fungi grow as filamentous hyphae - a mycelium is a tangled mass or mat of hyphae - higher forms of fungi form complex fruiting bodies that produce spores - molds have relatively small fruiting bodies - mushrooms, shelf fungi and gill fungi have more elaborate fruiting bodies - fungal classification is based on sexual cycle and type of fruiting bodies

23. Fungal Spores Unlike the bacterial endospore fungal spores are reproductive. A Bacillus makes one spore per cell and the function of the endospore is to survive harsh conditions like drying out, freezing or heat. Molds and Mushrooms make thousands of spores and scatter them in the wind as a way of reproducing and spreading. Fungal spores can be of medical significance because people can become allergic to mold spores and fungal infections are often acquires from inhalation or contact with spores. Fungal sporescan be either asexual vegetative spores that are produced by mitosis or sexual spores that are produced in the diploid state or shortly after diploid cells undergo meiosis. Sexual recombination involves the fusion of two haploid cells to form a diploid cell and some time later meiosis to form haploid cells again. The diploid stage may include cell growth and division, or it may not.

26. AscomycetesAn Ascus is a sac that contains haploid spores that are formed by a sexual cycle. Meiosis is part of spore formation. • faculty.clintoncc.suny.edu de.wikipedia.org

27. Life Cycle of a Typical Ascomycete Examples of Ascomycetes include: Morel Mushrooms, Saccharomyces cerevisiae (yeast used to make beer and wine) and Penicillium mold. from: io.uwinnipeg.ca

28. Basidiomycetes • www.botany.hawaii.edu comenius.susqu.edu

29. Basidiomycetes • Produce sexual spores at the tips of club-shaped cells that are called basidia (singular: basidium) • Aeriel hyphae are diploid • Examples include: Agaricus bisporus (a common edible mushroom, AKA: Button Mushroom, when immature, white and small, or the Portobello Mushroom, when mature, brown and large), Amanita muscaria (a hallucinogenic and toxic mushroom, or toadstool), Amanita phalloides (a very toxic toadstool), and Rhodotorula glutinis (an orange-colored yeast)

30. Fungi: Basidiomycetes Basidiospores develop at the end of club-shaped projections called basidia, which develop from the tightly woven intertwined hyphae of the basidocarp. pictures from: davidlnelson.md answers.com plantpath.cornell.edubiology.ed.ac.uk

31. Fungi: ZymycotaZygomycetes are mostly molds such as Rhizopus and Mucor species. They reproduce asexually via sporangiospores. The sexual cycle involves the production of a mass of diploid cells called the zygosporangium.Meiosis within the zygosporangium yields haploid cells that form an asexual hypha and sporangium.

32. Lichens Lichens are a community of microorganisms formed by a symbiotic partnership between a fungus and green algae or cyanobacteria.pictures from: royal botanic garden Edinburghrgbe.org.uk andbiologie.uni-hamburg.de Foliose lichens on a log from: botany.wisc.edu

33. Fungi 1 Which TWO of the following statements about fungi are TRUE?W. In the Ascomycetes, ascospores are produced during a sexual reproductive cycle while conidiospores are made during asexual reproduction. X. In the Basidiomycetes, basidiospores are produced during an asexual reproductive process. Y. Fungal classification is based on the morphology of the mycelium. Z. Some yeast species are classified in the Ascomycetes while others are classified as Basidiomycetes. A. choices W and X are true B. choices W and Y are true C. choices W and Z are true D. choices X and Y are true

34. Fungi 1 Which TWO of the following statements about fungi are TRUE?W. In the Ascomycetes, ascospores are produced during a sexual reproductive cycle while conidiospores are made during asexual reproduction. X. In the Basidiomycetes, basidiospores are produced during an asexual reproductive process. Y. Fungal classification is based on the morphology of the mycelium. Z. Some yeast species are classified in the Ascomycetes while others are classified as Basidiomycetes. A. choices W and X are true B. choices W and Y are true C. choices W and Z are true D. choices X and Y are true

35. Examples of Fungi a. Saccharomyces cerevisiae (yeast) Used to make beer and raise bread. Grows fastest in the presence of air, carries out alcoholic fermentation in the absence of air, the CO2 makes bread rise and the bubbles in beer b. Candida albicans (yeast) Normal flora of human gut, mouth and other mucous membranes. An overgrowth of yeast in the mouth causes thrush. A “yeast infection” is an overgrowth of vaginal Candida. Thrush in the throat is a sign of AIDS. c. Penicillium chrysogenum (mold) Used to produce penicillin. Grows fastest on glucose but produces antibiotic in stationary phase (when grown on lactose and limiting nitrogen) d. Phytophora infestans (water molds are now classified with diatoms and brown algae in Stramenopila) (Heterokont) Plant pathogen, there are many strains, one strain caused the Great Irish Potato blight of the 1850s, (late potato blight) other strains of Phytophora infestans can infect tomatoes. Potato blight

36. e. Aspergillus flavus (mold) Causes a black smut on grains such as peanuts, corn, rye,etc. Produces aflatoxin, a potent carcinogen. f. Claviceps purpurea (AKA: Ergot) (mold) Causes a rust on rye and other grains Produces hallucinogenic compounds similar to LSD (can be used to induce labor, lower blood pressure and ease migraines) g. Histoplasma capsulatum Spelunker’s disease or Ohio Valley Fever A dimorphic fungus: hyphae in soil, yeast form in lung infection May spread from lungs to other organs h. Coccidiodies immetis San Joaquin Valley Fever A dimorphic fungus: hyphae in soil, yeast form in lung infection i. Trichophyton rubrum A cause of dermatophytosis such as Athlete’s foot, or ringworm

37. Aspergillus flavus Fungus, Ascomycota, mold, conidia look like broccoli heads Aflatoxin liver carcinogen appears in improperly stored grain & peanuts high doses cause acute hepatic necrosis, followed by cirrhosis or hepatocarcinoma probability of liver disease increases in people with hepatitis B aflatoxins convert guanines into thymines Above: Aspergillus flavus on corn Image from: ces.ncsu.edu Left: Aspergillus flavus conidia Right: nuts

38. j. Penicillium italicum grows on citrus k. Penicillium roqueforti used to make blue cheese l. Blastomyces dermatitidis infects skin and/or lungs can cause a systemic disease called blastomycosis

39. Topical Fungal Infections • - Candida • - Athlete’s Foot • Ringworm • Candida albicans is a diploid fungus in the phylum Ascomycota. It is a commensal organism commonly found in the gut flora but it can also be an opportunistic pathogen. Thrush is an caused by an overabundance of Candida in the mouth. Candida is the most common opportunistic invader in diaper areas but diaper rash is primarily caused by irritation due to ammonia released from urine in the presence of urease enzyme found in feces. Other invaders of diaper rash regions include: Staphylococcus aureus, Proteus mirabilis, Enterococci and Pseudomonas aeruginosa.

40. Candida albicans – Diaper Rash

41. Athlete’s Foot

42. Dermatophytosis Athlete’s Foot is caused by mold, most commonly Trichophyton rubrum, Trichophyton mentagrophytes var. interdigitale and Epidermophyton floccosum. These fungal species can also cause “jock itch” and onychomycosis (fungal infection of a nail). Dermatophytes are amoung the few contagious fungi. Ringworm, also known as tinea corporis, is caused by Trichophyton rubrum, Microsporum gypseum and Microsporum canis. Limited infections can be treated with topical antifungal agents while more widespread infections can be treated with orally administered terbinafine.

43. Ringworm

44. SYSTEMIC FUNGAL INFECTIONS Fungal Infections of the Upper Respiratory Tract - Thrush Fungal Infections of the Lungs (and possibly spreading to other parts of the body) - Histoplasmosis - Coccidioidomycosis - Pneumocystosis - Pulmonary Blastomycosis - Aspergillosis

45. Thrush, caused by Candida albicans Thrush Candida albicans Infection of oral cavity. White patches on tongue.

46. Histoplasmosis Caused by the dimorphic fungus Histoplasma capsulatum. Which is found in soils contaminated by bat or bird droppings. Contracted by inhalation of spores in dust. Common sites to encounter this microorganism include: bat cave (Spelunker’s disease) or a chicken coop. The infection is usually benign but may spread to disseminated form (rare). The symptoms mimic TB and include: fever, cough, chest pain, shortness of breath. In severe cases it may cause lung cavities with tissue coughed up. Treated with Amphotercin B, ketoconazole

47. Fungi 2 Which of the following best describes Aspergillus flavus? A. A dimorphic fungus that causes Ohio Valley fever, it grows as a mold in soil that is rich in bird or bat droppings but as yeast in the human body. B. A yeast strain than can cause opportunistic infections in the human mouth and vagina. C. This plant pathogen, which causes potato blight, is not a fungus. It is a water mold and is now classified in the protozoa Kingdom Stramenopila. D. A mold that grows on rotting grain and makes a potent carcinogen. It is an Ascomycete but mostly reproduces by making asexual conidiospores.

48. Fungi 2 Which of the following best describes Aspergillus flavus? A. A dimorphic fungus that causes Ohio Valley fever, itgrows as a mold in soil that is rich in bird or bat droppings but as yeast in the human body. (Histoplasma capsulatum) B. A yeast strain than can cause opportunistic infections in the human mouth and vagina. (Candida albicans) C. This plant pathogen, which causes potato blight, is not a fungus. It’s a water mold now classified in the protozoa Kingdom Stramenopila. (Phytophora infestans) D. A mold that grows on rotting grain and makes a potent carcinogen. It is an Ascomycete but mostly reproduces by making asexual conidiospores. Some strains of Aspergillus flavus make aflatoxin!

49. Coccidioidomycosis Cocciodiomycosis is also called: Valley Fever, Desert Rheumatism, or San Jaquin Valley Fever. Coccidioides immitis is a dimorphic fungus that grows as a mold in the soil and as a yeast in the human lungs. It lives in soil in hot, dry, dusty areas (Southwest) Typically encountered when a person inhales airborne spores. The fungus invades the lungs producing an inflammatory response, fever, cough, chest pain, loss of appetite, weight loss and sometimes there is a hypersensitivity and rash. The infection is usually benign, but the disseminated form may follow (spreading to the meninges, bones, joints, skin). Treatment is with Amphotercin B and ketoconazole. Oct. 2001: California, people attending world championship of model airplane flying (endemic in Central Valley of CA). Dust generating event

50. Dissemination of Coccidioides immitis