FUNGI Chemoheterotroph, aerobic (molds) or facultatively anaerobic (yeasts) Mycology: Study of fungi Most fungi decomposers, few are parasites of plants and animals. bugs.bio.usyd.edu.au/.../TineaFoot.jpg Fig. 12.1

Characteristics of Fungi Hyphae: Filaments of cells, mostly septate Mycelium: Mass of hyphae. Molds: mostly filamentous. Yeasts: nonfilamentous, unicellular fungi. Budding yeasts divide asymmetrically. Dimorphic fungi: yeasts like 37C, molds 25C. Fungal spores differ from bacterial spores. Form from aerial hyphae. Growth in acidic, low-moisture, high osmotic pressure environments.

Fungal Diseases – Mycoses Systemic mycosis: infection deep within body, affects many tissues and organs. Histoplasmosis and coccidiomycosis. Subcutaneous mycosis: Saprophytic fungi, e.g.: Sporotrichosis. Cutaneous mycosis = Dermatomycosis: affects keratin-containing tissues (hair, nails, skin). Superficial mycosis: localized on hair shafts and superficial skin cells. Opportunistic mycoses: caused by normal microbiota or fungi that are not usually pathogenic (E.g.: Candidiasis and Pneumocystis pneumonia) usually systemic.

ALGAE Diatoms Mostly photoautotrophs, mostly in ocean Unicellular, store energy in form of oil Domoic acid  Neurological disease Ingestion of mussels that fed on diatomes (also affects birds and sealions) Dinoflagellates (plankton) Some produce neurotoxins: red tide Kills fish, marine mammals, and humans, e.g.: parasitic shellfish poisoning (PSP)

PROTOZOA Unicellular, eukaryotic chemoheterotrophs. Large and diverse group. Few are pathogenic. Found in soil and water and as normal microbiota in animals. Trophozoite: Vegetative form (feeding and growing). Asexual reproduction via fission, budding, or schizogony (multiple fission). Sexual reproduction via conjugation. Some protozoa can produce a cyst that provides protection during adverse environmental conditions.

Medically Important Protozoa Arcaezoa (lack mitochondria) Trichomonas and Giardia Microspora (no mitochondria and no microtubules) – diarrhea and keratoconjunctivitis in AIDS patients Amoebozoa (move via pseudopodia) Entamoeba (dysentery) Apicomplexa: not mobile, intracellular Plasmodium, Toxoplasma, Euglenozoa: Hemoflagellates Trypanosoma

HELMINTHS (Parasitic Worm) Kingdom: Animalia Phylum: Platyhelminthes (flatworms) Class: Trematodes (flukes) Class: Cestodes (tapeworms) Phylum: Nematoda (roundworms) few are human parasites Anatomy and life cycle modified for parasitism Adult stage in definitive host. Each larval stage in specific intermediate host. Characteristics: Reduced digestive system Reduced nervous system Reduced locomotion Complex reproduction

Life Cycle of Helminths Monoecious Male and female reproductive systems in one animal Dioecious Separate male and female Egg  larva(e)  adult

Nematodes Eggs infective for humans: Roundworms have a complete digestive system Eggs infective for humans: Ascariasis. most common worm infection in USA. (Most common worldwide; > 1 bio infected) (pinworm). Most common worm infection in USA (30% of children, 16% of adults infected) Live in human rectum. While infected person sleeps, female pinworms leave intestines through anus and deposit eggs on surrounding skin. Diagnosis with cellophane tape (scotch-tape test) first thing in the morning. Self limiting, but treatment of all family members recommended. .

Foundations of Virology Non-living agents that infect all life forms) Viral cultivation differs from bacterial cultivation  1,500 known viruses (estimates:  400,000 exist) Advent of EM allowed for visualization of viruses