Applied Microbiology Lecture 6 - Eukaryotic Microbes

Learning Objectives

  • Characteristics of Protists & Fungi: Understand defining traits and examples.

  • Comparison of Eukaryotes, Bacteria, Archaea: Discuss the controversy surrounding the term prokaryote.

  • Eukaryotic Microbes: Examples related to food spoilage, human disease, and environmental impact.

  • Eukaryotic Terminology Proficiency: Familiarity with key terms and cellular components.

Woese’s Phylogenetic Tree

  • Domains: Bacteria, Archaea, Eukarya.

Domain Eukarya

  • Protists: Generally larger and more complex; mostly unicellular; includes algae (photosynthetic), protozoa (motile), slime moulds (decomposition), and water moulds (plant pathogens).

  • Fungi: Absorb nutrients; includes yeasts (unicellular) and moulds (multicellular with hyphae).

Eukaryotic Cells

  • Defined as organisms with a true nucleus and membrane-bound organelles.

  • Structures include centrioles, ribosomes, nucleus, endoplasmic reticulum, Golgi apparatus, mitochondria, and lysosomes.

Cytoplasm & Cytoskeleton

  • Cytoskeleton: Provides cell structure, organization, and movement.

  • Components: Actin filaments (movement), intermediate filaments (strength), microtubules (tracks for organelle movement).

Cell Envelope

  • Structure: Plasma membrane (lipid bilayer), cell wall (if present, varies by organism), and glycocalyx (carbohydrates layer for protection and recognition).

Organelles**

  • Endoplasmic Reticulum (ER): Network for synthesis and transport; Rough ER for protein synthesis, Smooth ER for lipid synthesis.

  • Golgi Apparatus: Modifies, sorts, and packages cellular materials.

  • Nucleus: Contains genetic material; surrounded by double membrane; site of ribosome production in the nucleolus.

  • Mitochondrion: Site of ATP production through cellular respiration; contains DNA.

  • Lysosomes: Digestive organelles in animal cells; contain enzymes for breaking down macromolecules.

  • Chloroplasts: In photosynthetic organisms; site of photosynthesis.

Flagella and Cilia

  • Structure and Function: Involved in movement; different lengths and numbers per cell.

Protists Classification

  • Diverse Group: Includes algae and protozoa; reproduction mainly asexual.

  • Important Protists Examples: Giardia lamblia (giardiasis), Trichomonas vaginalis (trichomoniasis).

Fungi Characteristics

  • Mycology & Mycosis: Study of fungi and fungal infections.

  • Types of Fungi: Unicellular yeasts; multicellular moulds with hyphae.

  • Reproduction: Asexual (spores) and sexual methods; dimorphic fungi adapt based on environment.

  • Plant Pathogens: Fungi causing crop diseases (e.g., rusts, mildews).

Fungal Diseases

  • Categories: Systemic, subcutaneous, cutaneous, superficial, and opportunistic mycoses.

  • Diagnosis: Based on morphology and culture.

Evolutionary Relationships

  • Protists & Fungi: More than a single evolutionary lineage; ongoing classification developments based on molecular evidence.