EUKARYOTIC-MICROBES.pptx

EUKARYOTIC-MICROBES.pptx

1. Burton's Microbiology for the Health Sciences Chapter 5. Microbial Diversity Part 2: Eucaryotic Microbes

2. Chapter 5 Outline Fungi Characteristics Classification Medical Significance Lichens Slime Moulds Introduction Algae Characteristics and Classification Medical Significance Protozoa Characteristics Classification and Medical Significance

3. Meet the Microbes: Eukaryotes Image: Aspergillus fumigatus , CDC Aspergillus fumigatus From the Virtual Microbiology Classroom on ScienceProfOnline.com

4. Algae Characteristics and Classification Algae are photosynthetic , eukaryotic organisms. All algal cells consist of cytoplasm, a cell wall (usually), a cell membrane, a nucleus, plastids, ribosomes, mitochondria, and Golgi bodies. Some have a pellicle, a stigma, and/or flagella Algae range in size from unicellular microorganisms to large, multi-cellular. Algae produce energy by photosynthesis. Some may use organic nutrients.

5. Algae Characteristics and Classification, cont. Algae may be arranged in colonies or strands. Most algal cell walls contain cellulose . Depending on their photosynthetic pigments, algae are classified as green , golden , brown , or red algae. Algae include: diatoms, dinoflagellates, desmids, Spirogyra, Chlamydomonas, Volvox, and Euglena.

6. Algae are an important source of food , iodine , fertilizers , emulsifiers , and stabilizers and gelling agents for jams and culture media .

7. Algae: Medical Significance One genus of algae, Prototheca , is a very rare cause of human infections Causes protothecosis Algae in several other genera secrete toxic substances called phycotoxins Poisonous to humans, fish, and other animals If ingested by humans, the phycotoxins produced by the dinoflagellates that cause “ red tides ” can lead to a disease called paralytic shellfish poisoning.

8. Common Pond Water Algae and Protozoa

9. Protozoa Characteristics Protozoa are nonphotosynthetic , eucaryotic organisms. Most protozoa are unicellular and free-living; found in soil and water. Most protozoa are more animal-like than plant-like. All protozoal cells possess a variety of eucaryotic structures/organelles. Protozoa cannot make their own food ; they ingest whole algae, yeasts, bacteria, and smaller protozoa for nutrients.

10. Protozoa Characteristics, cont. Protozoa do not have cell walls, but some possess a thickened cell membrane called a “ pellicle ,” which serves the same purpose – protection. Some flagellates and ciliates ingest food through a primitive mouth or opening called a cytostome .

11. A typical protozoan life cycle has 2 stages – a trophozoite and a cyst. The trophozoite is the motile, feeding, dividing stage. The cyst is the nonmotile, dormant, survival stage. Some protozoa are parasites. Parasitic protozoa cause many human diseases, such as malaria, giardiasis, and trypanosomiasis.

12. Protozoa are divided into groups, based on their method of locomotion: Amebae move by means of pseudopodia (“false feet”) – example: Entamoeba histolytica , the cause of amebic dysentery. Ciliates move by means of hairlike cilia – example: Balantidium coli , the cause of balantidiasis . Flagellates move by means of whiplike flagella – example: Giardia lamblia , the cause of giardiasis. Sporozoa have no visible means of locomotion – example: Plasmodium spp., which cause malaria.

13. Protozoa That Cause Human Diseases Photomicrograph of a B. coli trophozoite (Arrows are pointing to the cilia). SEM of a Giardia lamblia trophozoite.

14. Image: Textbook, Microbiology, with Diseases by Taxonomy , R. Bauman . Protozoan Life Cycle From the Virtual Microbiology Classroom on ScienceProfOnline.com

15. Inflammatory disorder of the intestine, especially the colon, that results in severe diarrhea containing mucus and/or blood in the feces. Untreated, dysentery can be fatal due to massive dehydration. Can be caused by bacteria, protozans or parasitic worms. Image: Source Unknown Disease, Please : Dysentery From the Virtual Microbiology Classroom on ScienceProfOnline.com

16. Pathogenic species that feed off the intestinal lining. Infection results from eating food / drinking water contaminated by the organism - usually from feces. Chronic infection may result in malnourishment, blocking absorption of food across their intestinal wall. Protozoan Species : Giardia lamblia (aka G. intestinalis ) Images: Public Health Image Library, ( PHIL) #11649; #11632 & #3394 From the Virtual Microbiology Classroom on ScienceProfOnline.com My dog Lulu was diagnosed with Giardia . The vet ordered an ELISA test on a stool sample. Unlike a routine flotation stool check that gets parasite eggs and cysts to float to the top of a solution, the ELISA test looks for a specific antigen (or protein) of the Giardia organism. Giardiasis is typically treated over several days with the drug Metronidazole.

17. • A type of amoebae . • Eat and move by extending parts of their bodies to form pseudopods (SUE-dough-pods). • Exists asymptomatically in 10% of world’s population. • When disease develops, can be fatal (kills 100,000 annually). • Feeds on the lining of the gut. Irritation created can lead to condition known as amoebic dysentery. Protozoan Species : Entamoeba histolytica (ENT-ah-MEE-bah HISS-tow-LIT-ick-ah) Image: E. histolytica spore , CDC; E. histolytica life cycle , Mariana Ruiz; E. histolytica trophozoite, CDC From the Virtual Microbiology Classroom on ScienceProfOnline.com

18. Toxoplasma gondii . Can get from contaminated water, eating undercooked infected meat (especially pork, lamb & venison), or contact with cat feces that contain Toxoplasma . Mild symptoms are flu-like. Pregnant women and people with compromised immune systems could develop serious health problems. Severe toxoplasmosis can damage the brain, eyes and other organs. Severe cases are more likely in individuals who have weak immune systems. Disease : Toxoplasmosis

19. Life-threatening disease caused by Plasmodium protozoan parasites transmitted through the bites of infected mosquitoes. Symptoms include fever, chills, and flu-like illness. Left untreated can cause coma and death if progresses to cerebral malaria. Disease: Malaria

20. Fungi Characteristics The study of fungi is called mycology ; scientists who study fungi are called mycologists. Fungi are found virtually everywhere. Some fungi are harmful, some are beneficial. Fungi represent a diverse group of eucaryotic organisms that include yeasts, moulds, and fleshy fungi (e.g., mushrooms). Fungi are the “garbage disposers” of nature. Fungi are not plants – they are not photosynthetic.

21. Fungi Characteristics, cont. Fungal cell walls contain a polysaccharide called chitin . Some fungi are unicellular, while others grow as filaments called hyphae . Hyphae intertwine to form a mass called a mycelium . Some fungi have septate hyphae (the hyphae are divided into cells by cross walls or septa). Some fungi have aseptate hyphae (the hyphae do not have septa).

22. Fungi Reproduction Depending on the species, fungal cells can reproduce by budding, hyphal extension, or the formation of spores. There are 2 general categories of spores: Sexual spores Asexual spores (also called conidia ) Some fungi produce both asexual and sexual spores.

23. Fungal Colonies and Terms Relating to Hyphae

24. Fungi Classification Classification of fungi is based primarily on their mode of sexual reproduction and the type of sexual spore they produce. Deuteromycotina or Deuteromycetes include the medically important moulds such as Aspergillus and Penicillium. Fungi in this phylum have no mode of sexual reproduction or the mode of sexual reproduction is not known.

25. Microscopic Appearance of Various Fungi Aspergillus fumigatus Aspergilus flavus Penicillium sp . Curvularia sp. Scopulariopsis sp . Histoplasma capsulatum Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

26. Fungi: Yeasts Yeasts are eucaryotic , unicellular organisms that lack mycelia. Individual yeast cells, also referred to as blastospores or blastoconidia , can only be observed using a microscope. Yeasts usually reproduce by budding , but occasionally by a type of spore formation . A string of elongated buds is known as a pseudohypha (not really a hypha). Some yeasts produce thick-walled, spore-like structures called chlamydospores (or chlamydoconidia ).

27. Gram-Stained Clinical Specimen Containing Budding Yeast Cells

28. Microscopic Appearance of the Yeast Candida albicans A = Chlamydospores B = Pseudohyphae C = Budding yeast cells (blastospores)

29. Fungi: Yeasts, cont. Yeasts are found in soil and water and on the skins of many fruits and vegetables. Yeasts have been used for centuries to make wine and beer. Saccharomyces cerevisiae is a yeast used in baking. Candida albicans is the yeast most frequently isolated from human clinical specimens, and is also the fungus most frequently isolated from human clinical specimens.

30. Fungi: Yeasts, cont. Yeast colonies may be difficult to distinguish from bacterial colonies. A simple wet mount can be used to differentiate yeast colonies from bacterial colonies. Yeasts are larger than bacteria and are usually oval-shaped. Yeasts are often observed in the process of budding. Bacteria do not bud.

31. Colonies of C. albicans on Blood Agar

32. Gram-Stained Clinical Specimen Containing Yeasts, Bacteria, and White Blood Cells

33. Fungi: Moulds Often spelled “molds.” Moulds are often seen in water and soil and growing on food. Moulds produce cytoplasmic filaments called hyphae. Aerial hyphae extend above the surface of whatever the mould is growing on. Vegetative hyphae grow beneath the surface.

34. Fungi: Moulds, cont. Moulds have great commercial importance. Some produce antibiotics. Examples: Penicillium and Cephalosporium Some moulds are used to produce large quantities of enzymes that are used commercially. The flavor of cheeses like bleu cheese, Roquefort, camembert, and limburger are due to moulds that grow in them.

35. Fungi: Fleshy Fungi Include mushrooms, toadstools, puffballs and bracket fungi Consist of a network of filaments or strands (the mycelium) that grows in soil or on rotting logs The fruiting body that grows above the ground forms and releases spores Some mushrooms are edible; some are extremely toxic

36. Fungi Medical Significance A variety of fungi including yeasts, moulds , and some fleshy fungi, are of medical, veterinary and agricultural importance because of the diseases they cause in humans, animals, and plants. The infectious diseases of humans and animals that are caused by moulds are called mycoses . Fungal infections of humans are categorized as superficial, cutaneous, subcutaneous, and systemic mycoses.

37. Superficial and Cutaneous Mycoses Superficial mycoses are fungal infections of the outermost areas of the human body – hair, nails and epidermis. Cutaneous mycoses are fungal infections of the living layer of the skin, the dermis. A group of moulds collectively referred to as dermatophytes cause tinea (“ringworm”) infections. Note that “ringworm” infections have nothing to do with worms. The yeast, Candida albicans , can also cause cutaneous, oral, and vaginal infections.

38. Subcutaneous and Systemic Mycoses Subcutaneous and systemic mycoses are more severe types of fungal infections. Subcutaneous mycoses are fungal infections of the dermis and underlying tissues. Example: Madura foot. Systemic mycoses are fungal infections of the internal organs of the body. Spores of some pathogenic fungi may be inhaled with dust from contaminated soil or dried bird or bat feces. They may also enter through wounds of the hands and feet.

39. Subcutaneous and Systemic Mycoses, cont. Examples of deep-seated pulmonary infections include blastomycosis, coccidioidomycosis, cryptococcosis, and histoplasmosis. Inhalation of common bread moulds like Rhizopus and Mucor spp. can cause disease and even death in immunosuppressed patients. Diagnosis of mycoses is accomplished by culture techniques and immunodiagnostic procedures. Yeasts are identified using a series of biochemical tests. Moulds are identified using a combination of macroscopic and microscopic observations.

40. Fungal Infections: Types of Mycoses Superficial Mycoses: Most patients are not even aware that they have condition. Fungi only growing on dead skin, hair and nails. Fungus doesn’t secretes metabolites into body. Cutaneous Mycoses: Fungi growing and secreting metabolites into the skin. Person is definitely aware of the infection. An example of this is Epidermophyton floccosum , one of the causes of athlete's foot. Subcutaneous Mycoses: Fungus must be traumatically implanted into the body. Systemic Mycoses: Fungi are inhaled into the lungs and subsequently are transported to other internal organs, usually through the bloodstream.

41. Dimorphic Fungi A few fungi, including some pathogens, can live as either yeasts or moulds , depending on growth conditions. This phenomenon is known as dimorphism and the fungi are called dimorphic fungi . When grown in vitro at body temperature (37 o C), dimorphic fungi grow as yeasts and produce yeast colonies. When grown in vitro at room temperature (25 o C), dimorphic fungi exist as moulds , producing mould colonies. In vivo , dimorphic fungi exist as yeasts.

42. Dimorphic Fungi, cont. Dimorphic fungi that cause human diseases include: Histoplasma capsulatum (histoplasmosis) Sporothrix schenckii (sporotrichosis) Coccidioides immitis (coccidioidomycosis) Blastomyces dermatitidis (blastomycosis)

43. Fungi Heterotrophic (consumers) digest their food externally , secrete digestive enzymes and then absorb nutrient molecules into their cells. Examples: yeasts, molds, and mushrooms. Fungi are also used extensively by humans: yeasts responsible for fermentation of beer & bread mushroom farming is big industry produce some antibiotics

44. Fungal Infections Also called mycoses (singular mycosis) A fungus is actually a primitive vegetable. Mushrooms, mold and mildew are examples. You are more likely to get a fungal infection if you have a weakened immune system or take antibiotics. Fungi can be difficult to kill . For skin and nail infections medication applied directly to the infected area. Oral antifungal medicines available for serious infections.

45. Epidemiology of Mycoses Transmission and Prevalence of Fungal Infections It is your immune system that keeps you safe from fungal infection. Mycoses are typically acquired via inhalation , trauma or ingestion . Since usually not contagious, difficult to report incidence, other than epidemics or when they effect a specific population (such as AIDS patients). Image: Source unknown

46. True Fungal Pathogens vs. Opportunistic Fungi There are only four types of fungi that are considered true pathogens… - Blastomyces dermatitidis - Coccidioides immitis - Histoplasma capsulatum - Paracoccidioides brasiliensis … the rest are considered opportunistic. What’s the difference? True pathogenic fungi have the ability to actively attack and invade tissues of healthy individuals. Have specific enzymes and proteins that help them survive and reproduce within the body. Oppurtunistic fungi do not cause disease in healthy individuals, but can cause disease in those with weakened immune system. Pathogen : Blastomyces Opportunist : Aspergillus

47. True Fungal Pathogen Species: Blastomyces dermatitidis (blast-o-MICE-ease dur-ma-TID-id- iss ) What Is Blastomycosis ? Caused by f ungus found in soil in the eastern and central US. Infection occurs by inhalation of spores. Once inhaled, fungus grows and may disseminate through blood to other organs. Pulmonary Blastidiomycosis Resolves on its own in most people. In immune compromised can cause respiratory failure. Disseminated Blastidiomycosis If disseminates from lungs, can result in wart-like or recessed skin lesions (cutaneous blastidiomycosis ) or damage to bones ( osteoarticular blastidiomycosis ). AIDS patients are prone to develop meningitis from infection.

48. Opportunistic Fungal Pathogen Species: Aspergillus fumigatus Can cause disease aspergillosis . Has become leading infectious cause of death in leukemia and bone marrow transplant patients. Can result in: - allergic reaction - pulmonary mass - systemic infection - can also exacerbate asthma Five things increase a persons risk of experiencing opportunistic mycoses: Invasive medical procedures Medical therapies that weaken the immune system Certain preexisting conditions / Immune compromised Specific lifestyle factors

49. Lichens and Slime Moulds Lichens are observed as colored, often circular patches on tree trunks and rocks. Lichens are composed of an alga and a fungus living in a mutualistic relationship. Lichens are classified as protists. Slime moulds are found in soil and on rotting logs. Slime moulds have both fungal and protozoal characteristics. Slime moulds are classified as protists.

50. Different Types of Lichens

51. Helminths Helminths are parasitic worms that live inside their host. Examples: hook, whip, pin, heart and round worms Belong to the Kingdom Animalia. Live in and feed off living hosts. Receive nourishment and protection while disrupting their hosts' nutrient absorption, causing weakness and disease. Many types of helminths live in the digestive tract of their host. These are referred to as intestinal parasites . Watch a video clip, called Worm in My Butt , of a man describing his helminth infection.

52. You are my host ! I am burrowing up through your feet, to your throat, where you’ll swallow me. I live and grow, with my teeth hooked into the lining of your intestine! Ancylostoma duodenale From the Virtual Microbiology Classroom on ScienceProfOnline.com

53. Two species commonly infect humans: Ancylostoma duodenale and Necator americanus . Infect > 600 million worldwide. Eggs in fecally-contaminated soil mature into larvae. Larvae penetrate skin of foot (sometimes causing “ground itch”), ride the lymph system to the right side of heart, and pumped into lungs, are coughed up , and are then swallowed. Enter digestive system, and mature into adult worms in small intestines. Worms suck blood voraciously. Cause anemia, loss of iron & protein , and damage mucosa. Helminth : Hookworms

54. Parasitic nematode worm (helminth) that lives in small intestine of host. Taeniasis is the infection of humans with adult tapeworm of Taenia saginata (beef) or Taenia solium (pork). People with taeniasis may not know they have an infection because symptoms are usually mild or absent. T . solium tapeworm infections can lead to cysticercosis , a disease that can cause seizures, so it is important to seek treatment. Images: Tapeworm scolex , T. Port; Tapeworm life cycle , CDC, Tapeworm segments on cat’s tail, Worms in Cats website . Helminth : Tapeworms From the Virtual Microbiology Classroom on ScienceProfOnline.com