Microbiology 1 Week 1

Anton Von Leeuwenhoek

the first person to create a microscope

Francesco Redi

Created one of the first biological experiments. Used a closed meat jar and an open meat jar

Louis Pasteur

Performed a fermentation experiment where a culture exposed to air grew organisms, while the flask not exposed to air did not grow anything

Infectious organisms types

Viruses

Prions

Fungi

Protists

Helminths

Bacteria

Micrometer

1e-6

Nanometer

1e-9

Physical control agents

heat and radiation

Chemical control agents

disinfectants, antibiotics, and other drugs

Sterilization

removal of all microorganisms and infectious particles including spores and viruses

Bacteriostatic

prevention or slowing of bacterial reproduction and metabolism

Disinfection

a physical process used to destroy vegetative forms of pathogens

Sepsis

growth of microorganisms and or toxins in the blood or other sterile tissues

Antiseptics

chemical agents applied directly to the body

Infectious agent / pathogen

a microbe that is able to penetrate host defenses, invade sterile tissues, and multiply

True pathogen

capable of causing disease in healthy persons with normal immune defenses

Opportunistic pathogens

Become infections when the host's defenses are compromised or when established outside of natural environment

Pathogenicity

ability to cause harm to the host

Virulence

Determines the degree of pathogenicity, determined by an ability to establish itself in the host and cause damage

Virulence factor

something that contributes to the pathogenicity of a pathogen

All things that have pathogenicity are virulent, but...

not all things that have virulence are pathogenic

"Cidal"

kills something (whatever is in front determines what is killed, e.g. bactericidal)

Vegetative

a happy, growing form of microorganism

Spore

a survival form

Flagella

The only motile prokaryotic appendage

What shape are most bacteria that have flagella?

Rod-shaped (Bacilli)

3 components of flagella

Filament, Hook, and basal body

Flagellar filament

rigid helical structure composed of flagellin (causes the movement)

Flagellar Hook

universal joint that connects filament and basal body

Flagellar Basal Body

anchors flagellum to cell wall, consists of a rod and series of rings

How is flagellar motion created?

proton motive force generated from an electron transport chain

Mot protein

move protons to power the flagella

Monotrichous

one flagella

Lopgotrichous

many flagella on one side

Amphitrichous

one flagella on either side

Peritrichous

multiple flagella all over the cell

what are the two functions of the flagella?

Movement and immune system signalling

Taxis

movements of the flagella in response to a stimulus

Chemotaxi

Movement in response to chemical stimulus, regulated by chemoreceptors

Attractant-based gradients

the bacteria will tumble less often as it moves up the gradient

Repellent-based gradients

the bacteria will tumble more often down the gradient at increased speeds

Phototaxi

Movement in response to light

Osmotaxi

Movement in response to a water gradient

Aerotaxi

Movement towards or away from oxygen (depends on whether the bacterium likes oxygen or not)

Thermotaxi

Movement in response to temperature

Tumble

clockwise movement of flagella, Flagella will move randomly in a drunken stumble

Run

counterclockwise movement of flagella, Flagella will work together to move in one direction

Which is a counterproductive function of the flagella?

Immune system identification

PAMP

pathogen-associated molecular pattern (the flagella is a type of PAMP)

Axial Filament

found only in spirochetes, an internal flagella which causes a spinning and undulating pattern of locomotion

Pilus

non-motile bacterial appendage

Short pili

"fimbriae" used for attachment

How do short pili attach a bacterium to a host cell?

they help overcome electrostatic repulsion between the two cells (which carry a similar charge)

Long Pili

"F / sex pili" used for conjugation / transfer of genetic material

Glycocalyx

A bacterial appendage which helps with adherence

How can the glycocalyx be counterproductive for bacteria?

It can signal antibody stimulation

Capsule gylcocalyx

A hard layer, composed of repeating polysaccharide units, or proteins, or both, capsules are bound more tightly than slime layers

Slime layer glycocalyx

A gooey layer, a loose shield made of a polysaccharide coating, protects from dehydration and loss of nutrients as well as serving in adhesion

Cell Envelope

external covering of the cell that encloses the cytoplasm

Cell wall

Determines the shape of the bacterium and provides structural support

Mycoplasma

bacteria that do not have a cell wall

Do all bacteria have a cell wall?

No

Do all bacteria have a cell membrane?

Yes

Peptidoglycan

"murein" a semi-rigid molecular network of glycosidic linkages. Functions to prevent osmotic lysis

What are the two components that make up a cell wall?

NAG (N-acetyl glucosamine) and NAM (N-acetyl muramic acid)

Gram + cell wall

A single, thick layer of peptidoglycan on top of the cell membrane

Gram - cell wall

A thin layer of peptidoglycan between two layers of phospholipid membrane

T or F: Gram - cell walls have more proteins than gram +

True

Which type of cell wall contains lipopolysaccharides?

Gram -

Which type of cell wall contains lipoteichoic acid?

Gram +

Acid Fast / Mycobacteria

Contain large amounts of lipids such as mycolic acid

Has a large and waxy cell wall

What is the Archaean cell wall made of?

Proteins

Exotoxin

a toxin which is released away from the bacteria

Mesosome

invagination of the membrane, important for division

Components of bacterial cytoplasm

water and CHNOPS (carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur)

Bacterial Ribosomes

perform translation simultaneously with transcription

Inclusion bodies

aggregates of nutrients in prokaryotic cells

Plasmid

a collection of the cell's favourite genes, not all bacteria have a plasmid (always formed into a circle)

Bacterial Chromosome

contains all genetic material the cell needs to survive, organized circularly or linearly

Do all bacteria have plasmids?

No

Do all bacteria have chromosomes?

yes

Actin cytoskeleton

the cytoskeleton of prokaryotic cells

Which bacteria produce endospores?

Bacillus, clostridium, sporosarcina, coxiella (the only gram - producer)

Endospores

dormant bodies that are produced by bacteria that help the bacteria withstand hostile conditions

Spore coat

protein based outer coating (contains appendeges)

Cortex

peptidoglycan (pre-cell wall)

Inner and outer membrane

lipid based part of the spore that becomes cell membrane

Core

contains DNA, ribosomes, and large amounts of dipicolinic acid (plays a major role in dormancy

Clostridium tetani

Tetanus

The spore gets inside a puncture wound, the wound closes and creates an anaerobic environment for the spore to grow inside of

Clostridium botulinum

botulism

Infant botulism

spores get into infant digestive tract and causes problems (because the tract is undeveloped)

Foodborne botulism

the spore gets processed in a can and grows in an anaerobic environment, the toxin is then ingested

Bacillus anthracis

anthrax

can be breathed in or enter through cuts in the skin