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Questions and Answers
What is a key characteristic of viruses when they infect a host cell?
What is a key characteristic of viruses when they infect a host cell?
Why is COVID-19 particularly concerning in terms of its spread?
Why is COVID-19 particularly concerning in terms of its spread?
What major public health solution has shown promise in controlling pandemics like COVID-19?
What major public health solution has shown promise in controlling pandemics like COVID-19?
Which of the following conditions is NOT a result of viral infections?
Which of the following conditions is NOT a result of viral infections?
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Which of these diseases is caused by an RNA virus?
Which of these diseases is caused by an RNA virus?
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What are the two types of fungi that are classified based on their structure?
What are the two types of fungi that are classified based on their structure?
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Which type of mycosis affects the deepest parts of the body?
Which type of mycosis affects the deepest parts of the body?
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What is the primary function of mycelia in fungi?
What is the primary function of mycelia in fungi?
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What is the role of ergot toxin produced by Claviceps purpurea?
What is the role of ergot toxin produced by Claviceps purpurea?
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Which of the following accurately describes the cell walls of fungi?
Which of the following accurately describes the cell walls of fungi?
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Which of the following symptoms can be associated with gangrene?
Which of the following symptoms can be associated with gangrene?
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What type of fungi is primarily known for producing mycotoxins, including neurotoxins like phalloidin and amanitin?
What type of fungi is primarily known for producing mycotoxins, including neurotoxins like phalloidin and amanitin?
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What is the primary characteristic that distinguishes algae from other groups mentioned?
What is the primary characteristic that distinguishes algae from other groups mentioned?
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Which protozoan is known for its amoeboid movement and is pathogenic in humans?
Which protozoan is known for its amoeboid movement and is pathogenic in humans?
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Which organism is responsible for causing African sleeping sickness?
Which organism is responsible for causing African sleeping sickness?
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What do lichens represent in terms of biological relationships?
What do lichens represent in terms of biological relationships?
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Which type of fungi is commonly found on bread and fruit?
Which type of fungi is commonly found on bread and fruit?
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What characteristic is true for the majority of unicellular fungi?
What characteristic is true for the majority of unicellular fungi?
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What is the primary characteristic that distinguishes viruses from living cells?
What is the primary characteristic that distinguishes viruses from living cells?
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What does it mean for a virus to be an obligate intracellular parasite?
What does it mean for a virus to be an obligate intracellular parasite?
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Which of the following statements about bacteriophages is true?
Which of the following statements about bacteriophages is true?
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What is the core structure of a virus composed of?
What is the core structure of a virus composed of?
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What is the significance of the host range of a virus?
What is the significance of the host range of a virus?
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Which life cycle of a bacteriophage involves the integration of viral DNA into the host's genome?
Which life cycle of a bacteriophage involves the integration of viral DNA into the host's genome?
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What may surround the protein coat of some viruses?
What may surround the protein coat of some viruses?
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What term describes the phenomenon where viruses lead to a 'borrowed life'?
What term describes the phenomenon where viruses lead to a 'borrowed life'?
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Study Notes
Agricultural Microbiology - MICR20010
- Course code: MICR20010
- Course name: Agricultural Microbiology
- Lecturer: Dr. Tadhg Ó Cróinín
Exam Schedule
-
Practical Exam:
- Date: November 22nd
- Time: 2-3pm
- Duration: 1 hour
- Questions: 30 Multiple Choice Questions (MCQs)
- Material: Covers practical material (manual/online)
- Weightage: 15% of the total grade
-
Final Exam:
- Date: Thursday, December 12th
- Time: 9.30-11.30pm
- Duration: 2 hours
- Questions: 60 MCQs
- Material: Covers lecture material
- Weightage: 70% of the total grade
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
Viruses
- Acellular
- Consist of DNA or RNA core
- Core surrounded by a protein coat
- Coat may be enclosed in a lipid envelope
- Replicate only within a living host cell
Phages
- Bacteriophages are the most common biological entities on earth.
- Show incredible specificity, leading to the emergence of phage therapy.
- Their life cycle involves the transfer of genetic material.
Lytic or Lysogenic life cycles
- Diagrams illustrating the two types of viral replication cycles in a host cell. One cycle destroys the host cell and the other incorporates the viral genetic material into the host cell's genome.
- The diagram illustrates lysis and lysogeny.
A Borrowed Life
- Viruses, called bacteriophages, can infect and lead to a genetic takeover of bacteria (like Escherichia coli).
- Viruses have a unique existence between life forms and chemical processes.
- The origins of molecular biology are linked to early studies of pathogenic viruses that infect various hosts.
Structure of Viruses
- Not cells
- Small infectious particles made of a protein coat with nucleic acid inside (DNA or RNA)
- Images of specific types of viruses show different dimensions (sizes)
Viruses Replicate Only in Host Cells
- Obligate intracellular parasites; can only replicate inside host cells
- Each virus has a host range (limited number of host cells it can infect).
Viruses, Host Cells & CPE
- Viruses penetrate and grow inside the host cells.
- They enter host cells and disrupt cell functions like cell membrane, DNA/RNA, and protein synthesis.
- Viruses can cause cytopathic effects (CPE).
- Two image examples representing characteristic visible effects.
AIDS Cases
- Provides a graph tracking reported AIDS cases in the U.S. over time.
- Cases showed rapid increase initially, levelled out and then increased and stabilized after reaching a certain point.
Global HIV/AIDS Prevalence
- Visual representation (world map) demonstrating the geographic distribution of HIV/AIDS prevalence
- The map shows the concentration of HIV/AIDS prevalence in specific regions (Africa, North America, Latin America, etc)
"Our" Pandemic - Covid-19
- Coronavirus - an RNA virus
- Causes disease in mammals and birds
- Predominantly causing mild infections
- Notable exceptions: SARS, MERS, COVID-19
Why COVID-19 is Problematic
- Large number of asymptomatic carriers.
- Very effective human-to-human transmission.
- Severe disease in a subset of individuals.
Solutions for COVID-19
- Vaccines: showing great promise, but protection's indefinite duration is uncertain.
- Biotherapeutics: many drugs are being researched, including monoclonal antibodies.
- Testing and Contact Tracing: faster tests facilitating pandemic control.
Fungi
- Eukaryotes
- Cell walls composed of chitin
- Extract energy from organic compounds
- Include both molds and multicellular mushrooms.
- Mushroom mycelia consist of filaments called hyphae.
Fungal Diversity & Widespread Occurrence
- Vast number of fungi – Estimated 1.5 million species
- Numerous, diverse and widespread fungal species exist
- Fungi have complex networks of branched hyphae for absorption.
Fungal Diseases (Mycoses)
- Systemic: deep within the body
- Subcutaneous: beneath the skin
- Cutaneous: affect hair, skin, and nails
- Superficial: localized; e.g., hair shafts
Fungi as Parasites
- Toxic metabolic products can be produced from fungal growth within a host.
- Allergic reaction can be triggered.
- Tichothecene toxins inhibit protein synthesis
- Proteases produced by fungi
- Capsule formation in some types of fungi inhibits phagocytosis, e.g., Cryptococcus neoformans causing meningitis.
Pathogenic Properties of Fungi
- Ergot toxin (Claviceps purpurea): Causes hallucinogenic effects like LSD and other severe symptoms
- Aflatoxin (Aspergillus): carcinogenic
- Mycotoxins: Neurotoxins (Phalloidin, amanitin); e.g., Amanita phalloides (deathcap).
Filamentous Fungi - Molds
- Widespread on bread and fruit
- Examples: Aspergillus, Rhizopus
- Reproduce through sporulation and conidia
Macroscopic Fungi - Mushrooms
- Edible fungi (e.g., Agaricus)
- Poisonous variants (e.g., Amanita species)
- Normally mycelia, but occasionally fruit
Unicellular Fungi - Yeasts
- Cell division by budding and occasionally mating.
- Pathogenic versions like Candida albicans
- Facultative anaerobes.
- Important in environments containing sugars.
- Examples include Saccharomyces cerevisiae, baker's/brewer's yeast
The Algae
- Contain chlorophyll for oxygenic photosynthesis.
- Most are microscopic, some macroscopic (seaweeds).
- Diverse group
Diversity in Algae
- Generally unicellular or forming colonies (volvox, spirogyra)
- Contain chlorophyll and other pigments (xanthophyll, carotenoids)
Pathogenic Algae - Red Tides
- Dinoflagellates (Gonyaulax): harmful neurotoxins, kill fish and humans but harmless to shellfish.
- Pfeisteria: neurotoxin, causing lesions, has been known to devastate fish populations.
Lichens
- Symbiotic relationship between a fungus and an alga or cyanobacterium.
- Fungus provides an anchor, while the alga carries out photosynthesis.
Protozoa
- Unicellular organisms without cell walls.
- Usually colorless and motile.
- Do not form spores or fruiting bodies.
Protozoa - The Amoebae
- Amoeboid movement.
- Some are shelled.
- Pathogenic amoeba (Entamoeba histolytica).
Protozoa - The Ciliates
- Use cilia for movement and feeding.
- Paramecium
- Food engulfed into food vacuoles.
- Trichocysts allowing attachment.
Protozoa - Flagellates
- Motile using flagella.
- Euglenoids (Dunaliella)
- Some are pathogenic, e.g., Trypanosoma brucei causing African sleeping sickness.
Protozoa - The Sporozoans
- Obligate parasites
- Many are pathogenic.
- Examples: Plasmodium vivax, Toxoplasma gondii.
Typical Protozoa Representatives and Diseases
- Table that lists different groups of protozoa, representative species, habitats, and prevalent diseases. Showing correlations between the organisms and habitats associated with those diseases.
Anything Left?
- Diagrams that classify organisms
Prions
- Slow-acting, virtually indestructible infectious proteins.
- Cause brain diseases in mammals.
- Propagation occurs via conversion of normal proteins into prion versions.
- Examples include Scrapie (sheep), Mad Cow, Creutzfeldt-Jakob disease.
- These diseases are linked to abnormal protein aggregations.
Prion Disease Agent
- Agent insensitive to UV irradiation
- Distinct from conventional viruses
- Devoid of DNA/RNA
- Composed primarily of proteins (prion).
- The abnormal protein forms aggregates
Antibiotic Resistance in Microorganisms
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Description
Prepare for your Agricultural Microbiology exams with this comprehensive quiz covering key topics such as microorganisms, the immune system, pathogenic bacteria, and antibiotic resistance. Test your knowledge in a structured format with multiple choice questions based on lecture material and practical applications.
