Micro Lecture 4 Euka 2024 CA (2) PDF

Lecture 4 Eukaryotic Microorganisms Dr. Claire Atkinson [email protected]. uk  Today Lecture Break Quiz Tutorial–Malaria Learning outco...

Lecture 4 Eukaryotic Microorganisms Dr. Claire Atkinson [email protected]. uk  Today Lecture Break Quiz Tutorial–Malaria Learning outcomes Identify the characteristics of Fungi, Algae and Protozoan, Helminths Understand the differences between them Understand their life cycle Identify their involvement in human health  Do you know any EUKARYOTIC microorganism?  Do you know any EUKARYOTIC microorganism? Molds Mushrooms Fungi Yeasts Algae Protozoa Hemiths Have you ever eaten an algae? Most likely!  Classification of Eukaryotic Microorganisms With membrane-bound cell organelles and complex life cycle Algae Cellulose and a variety of glycoproteins Polysaccharide inclusions used in algal taxonomy Aquatic, photosynthetic, can be unicellular or complex multicellular Fungi Cellulose, glucosamine, and chitin Not all fungi have cell walls Can be unicellular or complex multicellular Protozoa No cell wall Are unicellular and require moist environment Slonczewski J.L,.Microbiology: An Evolving Science. 5th Edition Brock Biology of Microorganisms, Global Editiony Michael T. Madigan; Kelly S. Bender; Daniel H. Buckley; W. Matthew Sattley; David  Fungi Fungi are the most widely distributed organism on the earth Fungi are found free-living in the soil or water Some of these organisms create parasitic or symbiotic relationships with plants and animals. Fungi have been of great importance to human beings, as it produces food items like bread, cheese and wine  Fungal Characteristics Range from unicellular to whole mushrooms! They are free living and heterotrophic Metabolize complex carbohydrates In general resistant to osmotic pressure and can growth with low moisture They appear as: Brock Biology of Microorganisms, Global Editiony Michael T. yeast - mostly microscopic Madigan; Kelly S. Bender; Daniel H. Buckley; W. Matthew Sattley; David A. Stahl 2022 molds –Both microscopic and macroscopic fleshy fungi (mushrooms)- mostly macroscopic Have cell wall composed of strong flexible polysaccharide called chitin Slonczewski J.L,.Microbiology: An Evolving Science. 5th Edition  Fungal Characteristics Fungal colonies are vegetative Generally grow as filamentous, multicellular organisms They form filaments called hyphae or unicellular organisms Mycelium is a collective mass of hyphae- long and thread like Differ from plants/algae — do not contain chlorophyll Do not use photosynthesis They are heterotrophs Ribosomal RNA is 80s can be ID via 18s subunit Some synthesize toxins— ergot alkaloids, psychotropic agents, aflatoxins Brock Biology of Microorganisms, Global Editiony Michael T. Madigan; Kelly S. Bender; Daniel H. Buckley; W. Matthew Sattley; David A. Stahl 2012  Yeast Single cells that reproduce by budding (similar to binary fission) Some may become multicellular by connecting budding cells Classified according to the presence or absence of capsules, size and shape of their cells, daughter cell formation (budding, fission) formation of hyphae, presence of sexual spores, and genetics Do not require light for its growth May require oxygen or may grow in the absence of oxygen- fermentation  Life cycle of Fungi Fungi reproduce sexually and/or asexually asexual reproduction: Yeast typically bud in a similar to binary fission – Filamentous fungi reproduce by fragmentation of their hyphae and by spore formation -formation of sporangia Sporangia release spores into environment Spores can cause infection after inhalation Brock Biology of Microorganisms, Global Editiony Michael T. Madigan; Kelly S. Bender; Daniel H. Buckley; W. Matthew Sattley; David A. Stahl 2018  Life cycle of Fungi Sexual reproduction Introduces genetic variation Occurs when nutrients are limited or other unfavorable conditions are present all include the following three stages 1. plasmogamy (literally, “marriage or union of cytoplasm”), two haploid cells fuse, leading to a dikaryotic stage where two haploid nuclei coexist in a single cell. 2. karyogamy (“nuclear marriage”), the haploid nuclei fuse to form a diploid zygote nucleus. 3. meiosis back to haploid, at this stage, spores are disseminated into the environment. https://courses.lumenlearning.com/wm-biology2/chapter/  Molds Rapidly growing Asexual reproduction Develop hyphae that develop characteristic culture structure/colour Generally hyphae have cross walls called septa—divide the hyphae into distinct unicellular, cell-like units called septate hyphae Some have coenocytic hyphae— no septae In an appropriate environment, hyphae grow to form a mycelium, which is visible to the naked eye Brock Biology of Microorganisms, Global Editiony Michael T. Madigan; Kelly S. Bender; Daniel H. Buckley; W. Matthew Sattley; David A. Stahl 2022  Fungi Study of fungi—mycology Although there are over 100,000 known species of fungi only about 200 cause disease Immune system usually fights fungal invasion Can you think of a scenario where this may not be true? Play a major role in decomposition Brock Biology of Microorganisms, Global Editiony Michael T. Madigan; Kelly S. Bender; Daniel H. Buckley; W. Matthew Sattley; David A. Sta  Dimorphic Fungi Generally fungi can be divided into yeast and molds Some fungi can grow both forms depending on temperature—called dimorphic fungi As mold with septate hyphae in their natural environment and at 25° C in laboratory on fungal media As yeast in tissues—in laboratory at 37°C on enriched media Some can cause systemic mycoses – a fungal infection that affects the internal organs For example Candida spp, Cryptococcus spp. and Apergillus spp. Mosby items and derived items © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.  Fungal Pathogens Why are fungal pathogens in general more difficult to treat than bacterial pathogens? Questions  Algae Photosynthetic organisms Widespread in fresh and marine waters Main component of plankton Others are found in soil, on rocks, plants, and some even exist in hot springs or snow banks Medical concern—food poisoning caused by toxins of marine algae such as dinoflagellates Overgrowth of dinoflagellates causes the “red tide” Marine animals feed on dinoflagellates—accumulate toxin given off by the algae Toxin can persist for several months Shellfish poisoning in humans Mosby items and derived items © 2010 by Mosby, Slonczewski J.L,.Microbiology: An Evolving Science. 5th Edition Inc., an affiliate of Elsevier Inc.  Characteristics of Algae Two things in common All are photosynthetic All are aquatic They are not a unified group Differ in distribution, morphology, reproduction, and biochemical preferences Classification is problematic and has not been completely determined Can be unicellular (microscopic) or macroscopic  Classification of Algae Chlorophyta Green algae Pigments are chlorophyll a and b Most are unicellular or filamentous Living in freshwater ponds, lakes, and pools Form characteristic green to yellow scum Spirogyra Mosby items and derived items © 2010 by Mosby, Inc., an affiliate of Elsevier Inc. Slonczewski J.L,.Microbiology: An Evolving Science. 5th Edition  Classification of Algae Slonczewski J.L,.Microbiology: An Evolving Science. 5th Edition Rhodophyta Contain red accessory pigment Have cell walls containing agar Used in agar plates, thickener for soups, jellies, and ice cream Phaeophyta Brown algae— brown pigment in addition to chlorophyll and carotene Mosby items and derived items © 2010 by Mosby, Inc., an affiliate of Elsevier Brock Biology of Microorganisms, Global Editiony Michael T. Madigan; Kelly S. Bender; Daniel H. Buckley; Inc. W. Matthew Sattley; David A. Stahl 2022 Questions BREAK  Protozoans Defined by three common characteristics They are eukaryotes They are unicellular They lack a cell wall Many are free-living—others are potential parasites of humans and other animals Brock Biology of Microorganisms, Global Editiony Michael T. Madigan; Kelly S. Bender; Daniel H. Buckley; W. Matthew Sattley; David A. Stahl 202  Characteristics of Protozoans Diverse group With the exception of one subgroup, they are motile due to cilia, flagella, and/or pseudopodia Require moist environment to survive Most live in ponds, streams, lakes, and oceans Others live in moist soil, beach sand, and decaying organic matter Aquatic protozoans are important components of plankton Most are chemoheterotrophs and obtain food by Phagocytosis of bacteria Decaying organic matter Other protozoans Host tissue Some protozoans are photoautotrophic Brock Biology of Microorganisms, Global Editiony Michael T. Madigan; Kelly S. Bender; Daniel H. Buckley; W. Matthew Sattley; David A. Stahl 2022  Life Cycle of Protozoans Protozoans exist in a motile active, feeding state called the trophozoite When environment becomes unfavorable for feeding; many enter a dormant stage; cyst (spherical and lack cilia) Cysts can be distributed by air, which may play a role in transmitting diseases such as amebic dysentery Some exist as trophozoites only Others alter between trophozoite stage and cyst stage Main method of reproduction— asexual Schizogony— multiple fission; the nucleus undergoes multiple divisions before the cell divides Mosby items and derived items © 2010 by Mosby, Inc., an affiliate of Elsevier Inc. Brock Biology of Microorganisms, Global Editiony Michael T. Madigan; Kelly S. Bender; Daniel H. Buckley; W. Matthew Sattley; David A. Stahl 2018  Classification of Protozoans Trichomonas Classification has changed —advances in molecular genetics Giardia vaginalis Protozoans may colonize and infect various areas of the human body Archaezoa Do not have mitochondria Have mitosomes instead Many are spindle shaped with two or more flagella Human parasites include Trichomonas vaginalis and Giardia lamblia Mosby items and derived items © 2010 by Mosby, Inc., an affiliate Brock Biology of Microorganisms, Global Editiony Michael T. Madigan; Kelly S. Bender; Daniel H. Buckley; W. Matthew Sattley; David of Elsevier Inc. A. Stahl 2022  Classification of Protozoans - Microspora Do not have mitochondria Obligate intercellular parasites in animals including humans - Euglenozoa Large group of flagellated protozoa Haemoflagellates – blood parasites transmitted by bites Tryphamosoma (African sleeping sickness) - Ciliophora Generally harmless Only human pathogen: Balantidium coli Mosby items and derived items © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.  Classification of Protozoans Amoeba Amoebozoa Most are unicellular and common in soil and water Pseudopods Entamoeba histolytica— amoebic dysentery Transmitted through engestion of cysts Slonczewski J.L,.Microbiology: An Evolving Science. 5th Edition  Classification of Protozoans Apicomplexa Apicomplexa Complex life cycle requiring several hosts Plasmodium—causative agent of malaria Toxoplasma gondii— toxoplasmosis (host: cats) Plasmodium Toxoplasma gondii Slonczewski J.L,.Microbiology: An Evolving Science. 5th Edition Mosby items and derived items © 2010 by Mosby, Inc., an affiliate Brock Biology of Microorganisms, Global Editiony Michael T. Madigan; Kelly S. Bender; Daniel H. Buckley; W. Matthew Sattley; David A. Stahl 2022 of Elsevier Inc.  Slime Molds Have both fungal and amoebal characteristics More closely related to amoeba than fungi Cellular slime molds Most of their lives as single amoeboid cells; unfavorable conditions; cell aggregation Plasmodial slime molds Masses of protoplasm containing thousands of nuclei called plasmodium Brock Biology of Microorganisms, Global Editiony Michael T. Madigan; Kelly S. Bender; Daniel H. Buckley; W. Matthew Sattley; David A Stahl 2022  Helminths Not microbes Interesting to microbiologists because parasitic helminths produce microscopic infective and diagnostic stages in their life cycle—usually eggs or larvae Often found in blood, feces, and urine Must be distinguished from microbes Many parasitic helminths spend much of their life cycle in mammalian host Most of the ones affecting humans belong to flatworms and roundworms Adult animals usually large enough to be seen with the naked eye Eggs and larvae—microscopic Mosby items and derived items © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.  Life Cycle of Helminths Includes fertilized egg, larvae, and adult Can be extremely complex, involving a succession of intermediate hosts and a definite (final) host Larval development usually in intermediate host Adulthood and mating generally in the definite host Mosby items and derived items © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.  Classification of Helminths Trematodes Trematodes - flatworms Lung fluke, liver fluke, blood fluke All named by definite host tissue Cestodes or tapeworms Intestinal parasites Cestode (Tapeworm) Morphology LabXchance Mosby items and derived items © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.  Classification of Helminths Nematodes—roundworms Enterobius vermicularis Pinworm—spends life in human host Eggs transmitted to other host by fomite Ascaris lumbricoides Human parasite without intermediate host Necator americanus and Ancylostoma duodenale Hookworm Small intestine of humans Mosby items and derived items © 2010 by Mosby, Inc., an affiliate of Elsevier Inc. LabXchance  Life cycle of Helminths Tapeworm LabXchance Questions  Lecture 5 Tutorial Malaria Dr. Claire Atkinson ps://www.youtube.com/watch?v=wY-3psl1iBE C E G A F D H B  Sleeping Sickness - an introduction to African Trypanosomiasis https://www.youtube.com/watch?v=mKnlRVfjl-o Leishmaniasis - Plain and Simple https://www.youtube.com/watch?v=eOVpd7rORog Questions? Thanks