Unit_2A_Ch_5_Eukaryotic_Microbes_Fa24

Page 1: Course Information

• Title: Introduction to Eukaryotic Microbes - Unit 2A

• Main Topics Covered: Microbiology, Eukaryotic organisms including fungi, protists, helminths, and arthropods.

Page 2: Diversity of Eukaryotic Microbes

• Fungi

  • Includes molds and yeasts

• Protists (Protozoans):

  • Divided into subgroups:

    • Alveolates

    • Amoebas

    • Trypanosomes

• Helminths:

  • Nematodes

  • Cestodes

  • Trematodes

• Arthropods:

  • Insects (fleas, lice, mosquitoes)

  • Non-insects (mites)

Page 3: Structure of Eukaryotic Cells

• Cell Organelles:

  • Nucleus: Contains nucleolus and nuclear envelope

  • Cytoplasm: Contains various organelles

  • Plasma membrane: Encloses the cell

• Key Organelles:

  • Ribosome, mitochondrion, lysosome, Golgi complex, rough and smooth endoplasmic reticulum, peroxisome, centrosome, flagellum, cilia, microtubule, microfilament

• Distinguishing Features of Eukaryotic Cells:

  • Compartmentalized with membrane-bound organelles

  • Presence of a true nucleus

Page 4: Bacterial Reproduction

• Binary Fission: Most bacteria reproduce via binary fission.

• Stages Include:

  • DNA replication

  • Formation of division septum

  • Cell elongation

  • Cell separation

Page 5: Eukaryotic Genome

• Chromosome Structure:

  • Linear chromosomes located in the nucleus

• Haploid vs. Diploid:

  • Haploid (n): Seen in most fungi, many algae, and gametes of animals

  • Diploid (2n): Found in remaining fungi, algae, protozoa, and somatic cells of animals

Page 6: Human Somatic Genetics

• Chromosome Count:

  • Humans have 46 chromosomes organized into 23 pairs (diploid)

• Meiosis Overview:

  • Process of forming egg and sperm (haploid)

  • Key processes include fertilization, zygote formation, and embryo development

Page 7: Mitosis Phases

• Phases of Mitosis:

  • Prophase: Chromosomes condense and spindle fibers emerge.

  • Prometaphase: Nuclear envelope breaks down

  • Metaphase: Chromosomes align at the metaphase plate

  • Anaphase: Sister chromatids pulled apart to opposite poles

  • Telophase: Nuclear envelope forms around separated chromosomes

  • Cytokinesis: Division of cytoplasm (cleavage furrow in animal cells, cell plate in plant cells)

Page 8: Meiotic Process

• Meiosis Breakdown:

  • Meiosis I: Reduction division, resulting in haploid cells

  • Meiosis II: Similar to mitosis, results in further haploid cells

Page 9: Tetraploid Cells

• Tetraploidy Details:

  • Cells with 4 copies of each chromosome

  • Formation occurs through failed meiosis in certain species

Page 10: Reproductive Strategies of Eukaryotes

• Reproductive Methods:

  • Asexual: Mitosis, budding, schizogony, fission

  • Sexual: Meiosis

  • Some organisms exhibit both methods (e.g., algae, fungi, protozoa)

Page 11: Yeast Reproduction

• Budding in Yeast:

  • Parent yeast cell forms a bud which will develop into a new yeast cell

  • Example of a unicellular eukaryote's asexual reproduction

Page 12: Fungal Cell Structures

• Cytoskeletal Structure:

  • Coenocyte: Multinucleated fungal cell

  • Septate hyphae: Hyphae with septa between cells

• Mold Characteristics:

  • Coenocytic (nonseptate) hyphae

Page 13: Protozoan Reproduction

• Asexual Reproduction in Protozoa:

  • Usually occurs via mitosis

  • Schizogony: Rapid multiple mitoses without cytokinesis

• Example: Plasmodium species

Page 14: Sexual Reproduction in Protozoa

• Methods include:

  • Conjugation

  • Multiple fission

• Example: Paramecium caudatum

Page 15: Classifying Eukaryotic Parasites

• Unicellular Eukaryotic Parasites:

  • Previously classified in Kingdom Protista

  • Current classification based on rRNA sequencing

Page 16: Microbial Taxonomy of Protozoa

• Characteristics:

  • Unicellular and eukaryotic

  • Generally lack a cell wall, do not have true tissues

  • Most are harmless; some are parasites/pathogens

• Major Groups:

  • Excavata, Archaeplastida, SAR Clade, Unikonta

Page 17: Morphological Diversity of Protists

• Varieties of Motility Structures:

  • Pseudopods, flagella, cilia

  • Features include contractile vacuoles, ectoplasm, endoplasm

Page 18: Ecological Role of Phytoplankton

• Importance:

  • Primary producers in aquatic environments

  • Crucial for oxygen production

Page 19: Life Cycles and Reproductive Strategies in Protozoans

• Stages:

  • Trophozoite (active feeding stage)

  • Cyst (dormant resting stage)

• Life cycles range from simple to complex, with excystment and encystment occurring under varying environmental conditions

Page 20: Clinical Application: Amoebiasis

• Pathogen: Entamoeba histolytica

• Infectious Cycle:

  1. Human ingests cysts.

  2. Cysts excyst in the intestine, forming trophozoites.

  3. Trophozoites can ingest red blood cells, leading to disease.

  4. Dormant cysts exit in feces.

Page 21: Clinical Signs of Amoebiasis

• Signs/Symptoms:

  • Ranges from mild diarrhea to severe dysentery and colitis

• Transmission: Via fecal-oral route, contaminated water/food

• Diagnosis: Fecal tests for cysts and trophozoites

• Treatment: Metronidazole, tinidazole, etc.

Page 22: Acanthamoeba Spp. Clinical Application

• Diseases: Acanthamoeba keratitis and Amoebic Encephalitis

Page 23: Naegleria Fowleri Clinical Application

• Disease: Primary amoebic meningoencephalitis (PAM)

• Transmission: Water-related activities, enters through the nasal mucosa

• Symptoms: Central nervous system infection, often fatal

Page 24: Reported Cases of PAM in the United States

• Statistics: Breakdown of cases by state from 1962-2022

Page 25: Alveolates: Apicomplexans

• Characteristics:

  • Non-motile, possess unipolar apical complex for host cell invasion

• Example: Plasmodium sporozoite

Page 26: Complex Life Cycle of Apicomplexans

• Schizogony: Multi-stage life cycle involving mosquito and human hosts

Page 27: Clinically Significant Apicomplexans

• Notable Disease: Malaria caused by Plasmodium spp.

• Symptoms & Transmission: Through Anopheles mosquito, severe disease presentations

Page 28: Global Impact of Malaria

• Statistics from WHO: Significant morbidity and mortality associated with malaria

Page 29: Malaria Lifecycle

• Stages include transformation in both mosquito and human hosts, with significant multiplication steps in the liver and bloodstream.

Page 30: Clinical Application: Toxoplasmosis

• Etiology: Toxoplasma gondii

• Transmission: Generally asymptomatic, severe complications in immunocompromised individuals

Page 31: Clinical Application: Cryptosporidiosis

• Etiology: Cryptosporidium parvum

Page 32: Characteristics of Ciliates

• General Traits:

  • Motile via cilia, possess two nuclei (micronucleus, macronucleus)

  • Reproduce by binary fission and conjugation

Page 33: Balantidiasis Clinical Application

• Etiology: Balantidium coli

• Infective Stage: Cysts transmitted through contaminated water/food

Page 34: Excavata - Euglenozoa

• Habitat: Aquatic

• Key Traits: Unicellular with flagella, chloroplasts, mixotrophic metabolism

Page 35: African Trypanosomiasis

• Pathogen: Trypanosoma brucei

• Lifecycle: Involves various stages in tsetse fly and mammalian hosts

Page 36: American Trypanosomiasis (Chagas’ Disease)

• Etiology: Trypanosoma cruzi

• Transmission & Reservoir: Reduviid bug, primary reservoirs include opossums and armadillos

Page 37: Chagas’ Disease Symptoms

• Acute Symptoms: Changoma, Romaña's sign

• Chronic Symptoms: Megaesophagus, megacolon, heart failure

Page 38: African Trypanosomiasis Lifecycle

• Involves stages in tsetse fly and human bloodstream.

Page 39: Giardiasis Clinical Application

• Etiology: Giardia intestinalis

• Transmission: Fecal-oral

• Symptoms: Ingestion of cyst leads to trophozoite formation.

Page 40: Trichomoniasis Clinical Application

• Etiology: Trichomonas vaginalis

• Transmission: Direct STI

• Symptoms: Often asymptomatic, but notable symptoms include vaginitis in women and urethritis in men.

Page 41: Overview of Invertebrate Parasites

• Focus: Helminths and Arthropods as eukaryotic parasites

Page 42: Helminths Overview

• Characteristics: Complex life cycles involving definitive and intermediate hosts

Page 43: Helminths Features

• Traits: Multicellular, elongated body, bilateral symmetry, cuticle presence

Page 44: Types of Helminths

• Categories:

  • Trematodes (flukes)

  • Cestodes (tapeworms)

  • Nematodes (roundworms)

Page 45: Enterobiasis (Pinworm Infection)

• Etiology: Enterobius vermicularis

• Transmission: Fecal-oral (direct/indirect)

• Symptoms: Itching in the perianal area, common reinfection

Page 46: Life Cycle of Enterobius Vermicularis

• Eggs ingested, larvae hatch, and adult worms migrate to release eggs.

Page 47: Clinical Application: Trichinosis

• Etiology: Trichinella spiralis

• Transmission: Contaminated pork

Page 48: Trichinosis Symptoms

• Disease Presentation: Varies based on infection level

Page 49: Flatworms (Platyhelminthes)

• Characteristics: Oral and ventral suckers, bilateral symmetry.

Page 50: Trematodes Overview

• Digestive Structure: Simple with oral suckers and both sexes present.

Page 51: Cestodes Characteristics

• Transmission Mechanism: Ingestion of undercooked meat containing larvae.

Page 52: Tapeworm Lifecycle

• Lifecycle stages and interactions with hosts, involving egg shedding and transmission via fleas.

Page 53: Arthropods as Disease Vectors

• Description: Invertebrate animals that can transmit infectious diseases.

Page 54: Common Household Infestations

• Findings: Dust mites and bed bugs with descriptions of their impact in homes.

Page 55: Clinical Application: Scabies

• Etiology: Sarcoptes scabiei

• Transmission: Direct contact leading to skin rash and itching.

Page 56: Clinical Application: Pediculosis (Lice)

• Etiology: Different species including head and pubic lice.

• Transmission: Direct contact, causing dermatitis and itching.

Page 57: Unit 2A Eukaryotic Summary

• Overview: Introduction to fungi and their significance.

Page 58: Mycology and Mycologists

• Definitions: Study of fungi and specialists in the field.

Page 59: Examples of Fungal Organisms

• Species:

  • (a) Penicillium chrysogenum (multicellular)

  • (b) Saccharomyces cerevisiae (unicellular)

Page 60: Fungi Characteristics

• General Features:

  • Eukaryotic with a membrane-bound nucleus

  • Cell walls of chitin, no chlorophyll.

Page 61: Modes of Nutrition in Fungi

• Heterotrophic: Absorption methods, including saprophytes and parasitic organisms.

Page 62: Filamentous Fungi Features

• Structural Characteristics:

  • Hyphae: Septate or coenocytic

  • Mycelium consisting of vegetative and reproductive structures.

Page 63: Yeast Characteristics

• Identification:

  • Unicellular, reproduce asexually through budding.

  • Presence of pseudohyphae.

Page 64: Fungal Reproductive Strategies

• Asexual and Sexual Reproduction: Through spores and budding.

Page 65: Ascomycete Life Cycle

• Life Cycle Characteristics: Dominance of haploid phase, stages involve dikaryon and karyogamy.

Page 66: Yeast Life Cycle Overview

• Stages: Involves haploid mating, zygote formation, and a process of budding.

Page 67: Classification of Fungi

• Basis: Traditionally based on sexual stage with classifications including Zygomycota, Ascomycota, and others.

Page 68: Challenges in Fungal Classification

• Issues: Complications in identifying sexual stages, habitat influences, and dimorphism.

Page 69: Importance of Fungi

• Positive Contributions:

  • Essential decomposers, mycorrhizal symbionts aiding plant growth.

Page 70: Lichen Diversity

• Examples of Lichens:

  • Crustose, foliose, and fruticose types with ecological roles.

Page 71: Economic Impact of Fungi

• Uses:

  • Food production (mushrooms, fermentation products) and industrial applications.

Page 72: Fungi in Religion and Science

• Historical Significance: Used in religious rituals and research for medicinal properties.

Page 73: Negative Impact of Fungi

• Pathogenic Effects: Causes diseases (mycoses), allergies, and toxin production.

Page 74: Clinical Application: Dermatomycoses

• Etiology: Different fungi causing skin infections.

Page 75: Tinea Versicolor Clinical Application

• Etiology: Malassezia furfur, a common skin microbe leading to dandruff.

Page 76: Various Types of Tinea

• Classifications:

  • Tinea corporis, Tinea pedis, Tinea cruris, etc.

Page 77: Diagnosis of Tinea Capitis

• Diagnostic Techniques: Using UV light for identification.

Page 78: Clinical Application: Candidiasis

• Etiology: Candida species causing opportunistic infections in humans.

Page 79: Clinical Impact of Basidiomycota

• Human Pathogens: Species causing respiratory infections like cryptococcosis.

Page 80: Pneumocystis Jiroveci Overview

• Significance: Common pathogen in both immunocompromised and healthy individuals.

Course Information

Title: Introduction to Eukaryotic Microbes - Unit 2AMain Topics Covered: An overview of microbiology with a focus on eukaryotic organisms, including fungi, protists, helminths, and arthropods, emphasizing their diversity, structure, reproduction, and clinical significance.

Diversity of Eukaryotic Microbes

Fungi

• Types: Includes molds, which are filamentous fungi that reproduce via spores, and yeasts, which are unicellular fungi that reproduce typically by budding.

• Role: Fungi are essential decomposers that play a significant role in nutrient cycling within ecosystems.

Protists (Protozoans):

Divided into Subgroups:

• Alveolates: Characterized by the presence of alveoli under the plasma membrane. Exemplified by organisms such as dinoflagellates and ciliates.

• Amoebas: Protozoans that move using pseudopodia; they have complex behaviors and feeding mechanisms.

• Trypanosomes: Flagellated protozoa known for causing significant diseases (e.g., sleeping sickness).

Helminths:

• Nematodes (Roundworms): Have a complete digestive system and can be free-living or parasitic.

• Cestodes (Tapeworms): Flat, segmented worms that live in the host's intestines and absorb nutrients.

• Trematodes (Flukes): Have suckers for attachment to their host and can cause various diseases depending on the species.

Arthropods:

• Insects: Includes vectors such as fleas, lice, and mosquitoes, which can transmit pathogens.

• Non-insects: Includes mites and crustaceans, often significant in both ecology and as disease vectors.

Structure of Eukaryotic Cells

Cell Organelles:

• Nucleus: Contains genetic material housed within the nuclear envelope and contains the nucleolus responsible for ribosome production.

• Cytoplasm: The matrix where organelles reside, facilitating cellular metabolic activities.

• Plasma membrane: A lipid bilayer that regulates the entry and exit of substances, maintaining homeostasis.

Key Organelles:

• Ribosome: Protein synthesis, can be found free in the cytoplasm or bound to the endoplasmic reticulum.

• Mitochondrion: The powerhouse of the cell, involved in aerobic respiration and energy production.

• Lysosome: Contains enzymes for intracellular digestion.

• Golgi complex: Modifies, sorts, and packages proteins and lipids for secretion or internal use.

• Endoplasmic Reticulum: Rough ER is studded with ribosomes for protein synthesis, while smooth ER is involved in lipid synthesis.

• Peroxisome: Contains enzymes for oxidative reactions and the breakdown of fatty acids.

• Centrosome: Plays a critical role in cell division and organization of the microtubules.

• Flagellum and Cilia: Structures for motility in certain eukaryotic cells; flagella are typically longer and used for swimming, while cilia are shorter and used for movement of substances past the cell.

Distinguishing Features of Eukaryotic Cells:

• Characterized by compartmentalization with membrane-bound organelles, allowing for specialized functions.

• Presence of a true nucleus which segregates genetic material from the cytoplasm, a key distinction from prokaryotic cells.