Agricultural Microbiology Past Paper PDF

MICR20010 Agricultural Microbiology Dr. Tadhg Ó Cróinín  MICR20010 – Exam Schedule Practical Exam – 2-3pm November 22nd – 30 MCQ Questions over 1 hours – Only on Practical material (manual/online material) – Worth 15% of grade Final Exam – 9.30-11.30pm Thurs...

MICR20010 Agricultural Microbiology Dr. Tadhg Ó Cróinín  MICR20010 – Exam Schedule Practical Exam – 2-3pm November 22nd – 30 MCQ Questions over 1 hours – Only on Practical material (manual/online material) – Worth 15% of grade Final Exam – 9.30-11.30pm Thursday 12th December – Confirm on Exam timetable – 60 MCQ Questions over 2 hours – On Lecture Material – Worth 70% of grade Sample questions for both to be posted this week  MICR20010 - remaining lectures Lecture 10 – Microorganisms and Disease Lecture 11 – The Immune System Lecture 12 - Pathogenic Bacteria Lecture 13 – Pathogenic Fungi and Viruses Lecture 14 – Antibiotic Resistant Microorganisms Lecture 15 – Microbiology in the Food Industry – The Fungi Lecture 16 – Microbiology in the Food Industry - Fermentations Lecture 17 – The Nitrogen Cycle Where are the Viruses?  Viruses Acellular Consist of DNA or RNA core Core is surrounded by a protein coat Coat may be enclosed in a lipid envelope Viruses are replicated only when they are in a living host cell Figure 1.1e  Phages Bacteriophages are the most common biological entities on earth. Incredible specificity leading to emergence of phage therapy. Key for us is the life cycle of phages as these again involve transfer of genetic material Lytic or Lysogenic life cycles  A Borrowed Life Viruses called bacteriophages can infect and set in motion a genetic takeover of bacteria, such as Escherichia coli Viruses lead “a kind of borrowed life” between life-forms and chemicals The origins of molecular biology lie in early studies of viruses that infect bacteria Figure 19.1  Structure of Viruses Viruses are not cells A virus is a very small infectious particle consisting of nucleic acid enclosed in a protein coat and, in some cases, a membranous envelope  Viruses replicate only in host cells Viruses are obligate intracellular parasites, which means they can replicate only within a host cell Each virus has a host range, a limited number of host cells that it can infect.  Viruses Can penetrate and grow inside host Attach onto host cell and then enters – Effect host cell plasma membrane – Inhibit host DNA/RNA, protein synthesis – Can cause a Cytopathic effect (CPE) Cytoplasmic inclusion body in brain tissue-rabies Giant cell formed on measles infection Reported AIDS Cases in the United States Figure 14.4 Microbiology an introduction Figure 19.17 Fig 19.17 Microbiology an introduction “Our” Pandemic – Covid-19 A Coronavirus – RNA Viruses Cause diseases in Mammals and Birds Predominantly cause mild infections Some Exceptions – SARS – Severe acute respiratory syndrome 2003-4 – MERS – Middle East Respiratory Syndrome – 2012 – COVID-19 – SARS Cov-2  Why so problematic? Large numbers of people asymptomatic Very effective human to human spread Severe disease in a subset of individuals  The Solution? Vaccines – Vaccine results show great promise – Protection evident but for how long? Biotherapeutics – Large numbers of drugs entered pipeline including several monoclonal antibodies Test and Trace – Faster and cheaper tests to allow control of pandemic. Where are the Fungi and Protists? Remember these are Eukaryotes  Fungi Eukaryotes Chitin cell walls Use organic chemicals for energy Molds and mushrooms are multicellular, consisting of masses of mycelia, which are composed of filaments called hyphae Figure 1.1b Figure 31.6 introduction to Microbiology  Fungi are diverse and widespread About 100,000 species of fungi have been described It is estimated there are actually 1.5 million species of fungi Fungi consist of mycelia, networks of branched hyphae adapted for absorption Figure 31.3 Campbell Biology Figure 31.6 Campbell Biology  Fungal Diseases (Mycoses) Systemic mycoses: Deep within body Subcutaneous mycoses: Beneath the skin Cutaneous mycoses: Affect hair, skin, and nails Superficial mycoses: Localized, e.g., hair shafts  Fungi as parasites Toxic metabolic products from fungal growth in host Allergic response- fungal growth in homes Tichothecene toxins inhibit protein synthesis – Fusarium Proteases – Candida albicans (skin) , Trichophyton Capsule prevents phagocytosis – Cryptococcus neoformans- meningitis  Pathogenic Properties of Fungi Ergot toxin- – Claviceps purpurea (grains)- hallucinations like LSD – Killed 40,000 in France in 944. – characterized by gangrene, nervous spasms, burning sensations, hallucinations, and temporary insanity Aflatoxin- – Aspergillus- can be carcinogenic Mycotoxins – Neurotoxins: Phalloidin, amanitin Amanita phalloides- also known as deathcap Ergots on rye  Filamentous Fungi - Molds Widespread Found on bread and fruit Aspergillus Rhizopus Sporulation and conidia  Macropscopic Fungi - Mushrooms Produced for food - Agaricus Poisonous variants - Amanita Normally mycelium but occasionally fruiting bodies  Unicellular Fungi - The yeasts Cell division by budding and occasionally mating Can be pathogenic - Candida Albicans - filamentous Saccharomyces phase cerevisiae Facultative anaerobes and Bakers/Brewers yeast common where sugars are found  The Algae Contain chlorophyll and carry out oxygenic photosynthesis Most are microscopic but some can be macroscopic such as seaweeds Large and diverse group  Diversity in Algae Generally unicellular or colony forming - volvox and spirogyra Contain chlorphyll and other pigments such as Xanthophyll or caratenoids Pathogenic Algae - Red Tide Dinoflagellates Gonyaulax - neurotoxin kills fish and humans but harmless to shellfish Pfeisteria -Again a neurotoxin this time causing lesions - has been known to kill billions of fish  Lichens? Symbiotic relationship between fungus and an algae or cyanobacterium. Fungus provides anchor, algae provides the photosynthesis.  Protozoa Unicellular organisms without cell walls Generally colourless and motile Do not form spores or fruiting bodies  Protozoa – The Amoebae The Amoebae Some shelled Amoeboid movement Entamoeba histolytica pathogenic in humans  Protozoa – The Ciliates Use cilia to achieve motility Paramecium Food engulfed into a food vacuole Trichocysts to allow attachment Methanogenic archaea Parasitic?  Protozoa - Flagellates Motile Euglenoids – Dunaliella Some are pathogenic – Trypanosoma brucei African sleeping sickness via Tsetse fly  Protozoa – The Sporozoans Obligate parasites Many can be pathogenic Plasmodium vivax Toxoplasma gondii The Protozoa Anything left? Prions: The Simplest Infectious Agents Prions are slow-acting, virtually indestructible infectious proteins that cause brain diseases in mammals Prions propagate by converting normal proteins into the prion version Scrapie in sheep, mad cow disease, and Creutzfeldt-Jakob disease in humans are all caused by prions (Photo Credits: clockwise: Kunihiko Kobayashi; University of Iowa; Duke Medical School; University of California, Davis Prion disease agent  Agent insensitive to UV irradiation  distinct from conventional virus  devoid of DNA or RNA  The agent= composed primarily, even uniquely of a protein called Prion  Figure 19.11 Prion Original prion Aggregates of prions New Normal prion protein  CONVERSION PrPC PrPSc  Next on MICR20010 Antibiotic Resistance in Microorganisms Dr. Tadhg Ó Cróinín