MCB 2610 Exam #2 - Eukarya and Antibacterials

Clostridium botulinum

Gram-positive

Obligate anaerobes

Bacillus

Produce heat resistant endospores

Ferments sugars or Amino Acids

Causative agent of botulism

C. botulinum Locations

Soil, lake sediments, and decaying vegetation.

Botulism

Paralytic illness caused by a nerve toxin produced by C. botulinum.

Foodborne Botulism

Caused by eating foods that contain the botulinum toxin

Wound Botulism

Caused by a wound infected with C. botulinum, typically caused by injecting drugs or traumatic injury.

Inadvertent Botulism

Accidental overdoes of botulinum toxin

Infant Botulism

Caused by a child consuming spore or bacteria, which germinate in the intestine and release toxin.

Adult Intestinal Colonization Botulism

Caused by an adult consuming spores, which germinate in the intestine and release toxin.

Botulism Toxin Effect on Acetylcholine (Ach)

Blocks SNARE proteins from guiding Ach to the nerve membrane, leading to forced muscle relaxation and muscle paralysis.

Known Botulism Toxins

A, B, C, D, E, F, G, and F/A Hybrid.

A is most common in the United States; most responsible for foodborne outbreaks.

Harmful Effect of Botulism Toxin

Can travel into the central nervous system causing paralysis.

C. botulinum Symptoms

Double vision, Blurred vision, Drooping eyelids, Slurred speech, Difficulty Swallowing, Dry Mouth, and Muscle Weakness.

Infant C. botulinum Symptoms

Lethargy, Poor feeding, Constipation, Weak cry, and Poor Muscle Tone.

Untreated C. botulinum

Progress to cause paralysis of respiratory muscles and airway obstructions, later leading to death.

Foodborne Botulism Onset

4 to 36 Hours

Dr. Justinus Andreas Christian Kerner (1800s)

Performed experiments on himself by eating small amount of sour sausage and then documented the signs and symptoms.

1895

C. botulinum isolated from a Belgium scientist

Dr. Vernon Brooks (1950)

Find that C. botulinum blocks the release of acetylcholine from motor nerve terminals.

1989

BOTOX approved by the US FDA in December 1989 for muscle spasms.

C. botulinum Epidemiology (2024)

Foodborne: 9

Infant: 67

Wound: 12

Other: 5

Total: 93 cases

C. botulinum Diagnosis

Serum analysis looking for Botulism Toxin

Needs to be caught early

C. botulinum Treatments

Treated with an antitoxin that blocks the action of the toxin circulating in the blood. --> Only available from food.

If from food, inducing vomiting or enemas to remove food.

Supportive care

Antibiotics for Infection Site (Wounds)

Several Months of Medical care

Patients who survive will have fatigue and shortness of breath for years after.

C. botulinum Prevention

Boil home-canned foods for 10 minutes before eating

When in doubt, throw it out.

Eukaryotic Glycocalyx

Sticky carbohydrate extending from animal plasma membrane.

Bound to proteins and lipids in membrane --> Glycoproteins.

Eukaryotic Glycocalyx Function

Strengthens the cell surface, helps attach cells together, and cell-cell recognition.

Eukaryotic Flagella and Cili

Make the cell move or "beat" via microtubules.

Propel the cell through water.

Pseudopodia/Pseudopods

a temporary foot-like projection of the cytoplasm

Contains cytoplasm

Used for cellular locomotion

Eukaryotic Flagella

Few and long

Eukaryotic Cilia

Short and Many

Microtubule Array

Nine parallel pairs of microtubules surrounding a central pair of microtubules, 9+2 array.

Hollow Tube.

Microtubule Protein

Tubulin

How Does Eukaryotic Flagella Move

Whip-like motion.

Sliding of microtubules relative to each other causes flagellum to bend.

Powered by ATP.

Eukaryotic Cell Wall

Simpler than bacterial.

Eukaryotes that lack this have some kind of protective layer on them.

Plant Cell Wall Component

Cellulose

Fungus Cell Wall Component

Chitin and N-acetylglucosamine (NAG) units.

Yeast Cell Wall Component

Glucan and Mannan

Animal Cell Wall

Does not exist.

Protozoa Cell Wall Homolog

Flexible outer protein covering called a pellicle.

Eukaryotic Plasma Membrane

Very similar to Prokaryotic.

Contains carbohydrates for attachment sites.

Contains sterols/cholesterol for resistance to osmotic lysis and increase flexibility.

Phospholipid bilayer.

Transport Methods of Eukaryotic Plasma Membrane

Simple Diffusion, Facilitative Diffusion, Osmosis, Active Transport, and Endocytosis.

Phagocytosis

Pseudopods extend and and engulf particles

Pinocytosis

Membrane folds inward, bringing fluid and dissolved substances

Receptor-mediated endocytosis

Binding to a receptor then membrane folds in.

What is the nature of eukaryotic cytoplasm?

Semifluid, gelatinous, nutrient matrix

What are the complex internal structures found in eukaryotic cytoplasm?

Microfilaments, intermediate filaments, and microtubules

Where do most metabolic reactions occur in eukaryotic cells?

In the cytoplasm

What functions does the eukaryotic cytoplasm provide?

Support, shape, and assists in solute/ion transport

What does eukaryotic cytoplasm contain?

Storage granules and organelles

Eukaryotic Ribosome

Site for Protein Synthesis

80s

Small Eukaryotic Ribosomal Subunit

40s

Large Eukaryotic Ribosomal Subunit

60s

Free Ribosome

Suspended in the cytosol, makes proteins that function in the cytosol.

Bound Ribosome

Attached to the outside of the Rough ER, makes proteins for insertion into membranes.

Chloroplast and Mitochondria Ribosomes

70s, endosymbiont theory.

Nucleus

Contains chromosomes

DNA

Nuclear Envelope

Encloses the nucleus, covered in pores.

Pore Complex

Regulates entry and exit of proteins and RNAs, as well as large complexes of macromolecules.

Chromosomes

Area where DNA is organized.

Structures that carry genetic information.

Each one contains one long linear DNA molecules associated with many proteins/histones.

Eukaryotic DNA Histone Complex

Octamer, 160 Nucleotide Base Pairs.

Chromatin

Histones and DNA together.

Characteristic of A Particular Species

The number and composition of chromosomes and the number of genes on each chromosome.

Human (46), Elephants (56), Nematodes (11)

Endoplasmic Reticulum

Transport network

Golgi Complex

Membrane formation and secretion

Lysozyme

Digestive Enzyme

Membranous sac with acid environment.

Lysozyme Function

Hydrolytic enzymes that digest various molecules without harming cytoplasmic components of the cell.

Can digest bacteria.

Vacuole

Brings food into cells and provides support.

Mitochondria

Powerplant, powerhouse, energy factories of the cell.

Found in all eukaryotic cells.

ATP molecules are produced within by cellular respiration.

Number depends on activities of the cell, can grow and divide independently.

Endosymbiont Theory Based On Eukaryotic Mitochondria

Double membranes, Contain ribosomes to produce their own proteins, Circular DNA, and grow independent within the cell.

Chloroplast

Photosynthesis

Peroxisome

Oxidation of fatty acids; destroys H2O2

Centrosome

Consists of protein fibers and centrioles, important for cell division

Tsetse Flies Endosymbiont

Wigglesworthia, Fly has a specialized organ for it, Sodalis glossinidius

Paramecium Endosymbiont

Ingesting algae and using them for photosynthesis.

Protozoa Harmful Microorganisms

Small amount needed to cause disease

Can be intracellular or extracellular

Unable to withstand drying --> cannot be free in environment

Arthropod Vectors

Examples of Protozoa

Plasmodium falciparum, Trypanosoma brucei, Giardia lamblia, and Toxoplasma gondii

Protozoa

Nonphotosynthetic, eukaryotic organisms.

Unicellular

Free-living

More animal-like than plant-like.

Protozoa Locations

Soil and water

Protozoa Motility

Divided into groups based on their method of locomotion.

Amebae

Pseudopodia

Ciliates

Cilia

Flagellates

Flagella

Amoeboid

Entamoeba histolytica; Parasite in GI tract

Flagellated Protozoans

Giardiasis

Trypanosomiasis

- African sleeping Disease (Tsetse flies)

- Chagas Disease (Kissing Bugs)

Ciliated Protozoans

Balantidium coli

Spore-forming Protozoans

Malaria (Plasmodium)

Helminths

Harmful Eukaryote whose life cycle is part microscopic, when it is typically spread.

Helminths Example

Roundworms and Flatworms

Taeniasis

adult tapeworm infects the intestine; from livestock.

Mycology

Study of Fungi

Fungi

Some are harmful, some are beneficial.

Yeasts, molds and mushrooms.

Not photosynthetic.

Fungi Cell Membrane

Ergosterols; antifungal drugs.

Fungi Growth

Unicellular and Hyphae

Fungal Spores

Help classify, either asexual or sexual.

Harmful fungal spore

Blastomycosis; Blastomyces dermatitidis

Yeast Locations

Soil and water, On skins of produce, and On Humans

Used in baking.

Saccharomyces cerevisiae

Most frequent yeast isolated from human clinical specimens

Candida albicans

Mycosis

fungal infection

Fungal Pathogen Cycle

Between Hyphae and yeast-like (Dimorphic)

Fungal Diseases

Chronic (long lasting)

Fungi grow slow

Hard to treat