Introduction to Microbiology and Key Concepts (lecture 1)

Microbiology

Study of microorganisms, which are organisms that are too small to be seen with the naked eye, including bacteria, viruses, fungi, and protozoa.

True microorganisms

All microscopic living organisms.

Biotechnology

The use of living systems and organisms to develop or create products, often involving genetic manipulation.

Ubiquity

The concept that microorganisms are found everywhere in the environment, from extreme conditions to human bodies.

Biological Decomposition

The process by which organic substances are broken down into simpler organic or inorganic matter, essential for nutrient cycling.

Bioremediation

Introduction of microbes into the environment to restore stability or to clean up toxic pollutants.

Pathogen

An organism that causes disease.

Primary pathogens

Pathogens that can cause disease in healthy individuals.

Opportunistic pathogens

Pathogens that cause disease when the host's immune system is compromised.

Germ Theory of Disease

States that specific diseases are caused by specific microorganisms.

Robert Hooke

First observations of microbes in the 1600s.

Anton van Leeuwenhoek

Made a crude microscope to examine threads in fabrics and made drawings of what he called 'animalcules' in rainwater and scraped from his teeth.

Tyndall

Found that microbes in the dust and air have high heat resistance.

Lister

First to utilize handwashing and misting operating rooms with antiseptic chemicals.

Cohn

Found endospores.

Koch

Linked a specific microorganism with a specific disease.

Holmes

Observed that mothers who gave birth at home experienced fewer infections than mothers who gave birth in the hospital.

Semmelweis

Women became infected in the maternity ward after examinations by physicians who had been working in the autopsy rooms without washing their hands.

Louis Pasteur

Disproved spontaneous generation and developed pasteurization, demonstrating that microorganisms cause fermentation and spoilage.

Germ Theory

Diseases are caused by microscopic organisms, (germs).

Spontaneous Generation

The disproven theory that living organisms can arise from non-living matter.

Scientific Method

0. Observation 1. Question 2. Hypothesis 3. Experiment 4. Conclusion 5. Repeat.

Taxonomy

The science of classifying biological species.

Levels of organization

Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species (DKPCOFGS).

Binomial nomenclature

Naming a bacterial species, which includes the genus name followed by the species identifier.

3 Domains of Life

1. Bacteria 2. Archaea 3. Eukarya.

Bacterial Cell Structures

All bacteria possess: cell membrane, chromosome, and ribosomes.

Most Bacteria

Have cell wall, flagella, pili.

Some Bacteria

Have glycocalyx (made of polysaccharide units).

Flagella 4 Parts

Basal body, filament, hook, ring.

Chemotaxis

(Movement toward or away from chemical stimuli).

Phototaxis

(Movement toward or away from light).

Pili

Made of pilin protein, provide adhesion, not locomotion

Run

Straight line towards stimulus

Tumble

Random changing of directions from stimulus

Spirochetes

Group that has axial filaments

Fimbria

Small, bristle-like fibers, responsible for biofilms, provide adhesion, not locomotion

Cell Membrane Composition

Phospholipid bilayer, chromosome, nucleoid, inclusion, Cytoskeleton, ribosomes

Cell Membrane Function

Regulate transport, selective permeability

OUTER Membrane Composition

LPS, lipoproteins, endotoxin, porin proteins

OUTER Membrane Function

LPS for protection against deterrents, lipoproteins anchor to peptidoglycan, endotoxin stimulates fever, porin protein act as pores.

Glycocalyx

2 forms: Slime layer & Capsule

Cell Envelope

Consists of the cell wall and cell membrane; gram-positive bacteria have a thick peptidoglycan layer, while gram-negative bacteria have a thin layer and an outer membrane.

Teichoic Acids

Found in gram-positive bacteria, they provide cell wall maintenance and play a role in acidic charge on cell surface maintenance and enlargement during cell division.

Biofilm

Microbial habitats that attract more microbes, cause chronic infections and antimicrobial drug resistance.

Cell Wall Composition

Composed of Peptidoglycan.

MYCOPLASMA

The Genus with no cell wall.

Waxy Coating Genera

Two genera with waxy coating: Mycobacterium, nocardia; waxy coating is mycolic acid.

Nucleoid

The region in bacteria where the circular DNA is located, distinct from eukaryotic nuclei.

Bacterial DNA

Typically circular and supercoiled.

Bacteria Ribosome

70S ribosomes, essential for protein synthesis, differing from the 80S ribosomes found in eukaryotes.

Plasmid

Nonessential pieces of DNA, give protective traits to other bacteria.

Function of Inclusions

Storage sites for metabolic products.

Function of Granules

Type of inclusion; inorganic compounds not enclosed in membranes.

Cytoskeleton

Made of long polymers of proteins similar to eukaryotic actin.

Cytoskeleton Function

Contribute to cell shape, potential target for antibiotic development.

Sporulation

The process by which vegetative bacteria form endospores, a dormant and highly resistant form that can survive extreme conditions.

Purpose of Sporulation

To survive.

Germination

The process by which an endospore returns to its vegetative state when conditions become favorable.

Genera Producing Spores

Bacillus, clostridium, clostridioides, sporolactobacillus.

Pathogenic Genera

Bacillus anthracis, Clostridium tetani, C. perfringens, C. botulinum.

Bacterial Shapes

The 3 major shapes of bacteria: cocci, bacilli and spirilla.

Bacteria Arrangements

Diplococci (pairs), tetrads (groups of 4), staphylococci (irregular), streptococci (few to hundreds of chains), sarcina (cubical, 8, 16+).

Aerobic

Use oxygen in metabolism.

Anaerobic

Do not use oxygen in metabolism.

Facultative

May or may not use oxygen.

Bergey's Manual of Systemic Bacteriology

The definitive published source for bacterial and archaea classification, combines phenotypic information with rRNA sequencing for classification.

Bergey's Manual of Determinative Bacteriology

Uses ONLY phenotypic characteristics.

Gracilicutes

G (-) cell walls, thin skinned.

Firmicutes

G (+) cell walls, thick skinned.

Tenericutes

Lack cell walls, soft.

Mendosicutes

Archaea.

Species

Collection of bacterial cells which share an overall pattern of similar traits.

Subspecies

Same species that have differing characteristics.

Serotype

Species that stimulate a distinct pattern of antibody responses.

Archaea

Has MORE in common with eukaryotes than bacteria; still prokaryotic (no nucleus) most primitive lifeform.