Microbiology Test 1

Microbiology in Disease - Prof Newsome MTSU Test 1

Microbiology

Deals with living things too small to be seen without a microscope

Microorganisms

Exist as single cells or clumps of cells

The two groups into which all living cells can be divided

Eukaryotic and prokaryotic

Prokaryotic organisms

Bacteria and Archaea

Viruses

Are not a cell

they live inside a eukaryotic or prokaryotic cell and have no metabolism outside the host cell

Virus

How should viruses be referred to according to the handout?

Viral agents

Anton van Leeuwenhoek

1600s microbiologist; invented single lens microscope and first person to see bacteria

Louis Pasteur

1860s - Invented what we now call pasteurization and disproved spontaneous generation

Pasteurization

A process of mild heating to kill susceptible spoilage microorganisms and vegetative pathogens

Tiny, dormant cells/survival structures produced by microorganisms and plants that pasteurization CANNOT kill

Spores

Approximately what temperature is used for pasteurization?

158°F or 70°C

Types of spores

Salmonella, E-Coli, Listeria

Germ theory

The concept that microorganisms (bacteria) can cause specific diseases

Dr. Semmelweis

Hungarian doctor who clearly showed that women in maternity wards of hospitals became infected more often than women who delivered by midwife at home

What did doctors do that contributed to infections in maternity wards?

They went from autopsy to delivery without washing their hands

Robert Koch

Scientist associated with Koch's postulates

Koch's postulates

A set of criteria that must be met before one can say a specific disease is caused by a specific microorganism

Koch's postulates serve as what in microbiology?

A cornerstone of microbiology

Koch's first postulate

The microbe is found in every case of the disease and absent from healthy individuals

Koch's second postulate

The microbe must be isolated from an infected individual and grown in a pure culture

Koch's third postulate

Inoculate a healthy host and observe the same resultant disease

Koch's fourth postulate

Isolate the same microbe from the diseased host

Joseph Lister

English surgeon who applied the germ concept to surgery in the late 1800s

Joseph Lister's contribution

Used chemical disinfection in the treatment of surgical instruments

Effect of Lister's chemical disinfection

Greatly reduced the number of post-surgical wound infections

Late 1800s

Joseph Lister applied the germ concept to surgery

Early 1900s

Concept of chemotherapeutic agents

Late 1930s

Sulfa drugs

Chemotherapeutic agents

Chemicals with therapeutic value

Alexander Fleming

Scottish microbiologist who discovered penicillin in late 1930s

Penicillin

An antibiotic derived from the common mold Penicillium

Penicillium

A common mold that often has a green color

Antibiotic

A metabolite produced by one microorganism that inhibits a specific metabolic pathway in another microorganism

Most antibiotics function by inhibiting what?

Cell wall synthesis
Protein synthesis
DNA synthesis
Metabolism (folic acid synthesis)
Cytoplasmic membrane function

Antibiotics: cell wall target

Inhibition of cell wall synthesis

Antibiotics: protein target

Inhibition of protein synthesis

Antibiotics: DNA target

Inhibition of DNA synthesis

Antibiotics: metabolism target

Inhibition of metabolism; folic acid synthesis

Antibiotics: membrane target

Inhibition of cytoplasmic membrane function

Eukaryotic cell

Includes all pathogenic protozoa such as malaria and Trichomonas, as well as all fungi and algae

Eukaryotic cell: nucleus

Contains chromosomes, and DNA is wrapped around histone proteins

Eukaryotic cell: mitochondria

Has its own DNA and replicates inside the cell

Mitochondria and energy

The more energy needed, the more mitochondria the cell has

We get our mitochondria only from our

Mother

Mitochondrial DNA

Can be used for interesting genetic studies and forensic analysis

Almost all bacteria are

Prokaryotic cells

Bacterial DNA

Is not enclosed in a nucleus; bacteria lack a defined cell nucleus

Bacterial DNA and histones

Bacterial DNA is not wrapped around histone proteins

Bacterial chromosome

DNA is circular, not linear

How many chromosomes do bacteria have?

All bacteria have a single circular chromosome

Bacteria have no

Mitochondria

Bacterial cell wall

Bacteria almost always have a cell wall composed of peptidoglycan

Peptidoglycan

The substance that composes the cell wall of almost all bacteria

Why is the bacterial peptidoglycan cell wall of great medical importance?

It is an important target for antibiotics because human cells do not have peptidoglycan cell walls

Eukaryotic vs. prokaryotic: nucleus

Eukaryotic cells have a defined nucleus; prokaryotic cells do not

Eukaryotic vs. prokaryotic: DNA

Eukaryotic DNA is wrapped around histone proteins and enclosed in a nucleus; bacterial DNA is not enclosed in a nucleus and is not wrapped around histones

Eukaryotic vs. bacterial chromosome

Eukaryotic chromosomes are linear; bacterial chromosomes are circular

Eukaryotic vs. bacterial mitochondria

Eukaryotic cells have mitochondria; bacteria do not

Eukaryotic vs. bacterial cell wall

Bacteria almost always have a peptidoglycan cell wall; eukaryotic cells do not have peptidoglycan

Paul Ehrlich

The German scientist who discovered that arsenic helped against syphilis as chemotherapeutic agent

Why are Eukaryotic cells more difficult to satisfactorily treat?

Very similar to human cells + lacks unique specific enzymes

Almost all bacteria need what for metabolism?

Folic Acid (converts paba to folic acid)

Originally derived as sulfur byproducts able to inhibit the conversion of paba to folic acid in bacteria, and are pioneer drugs for antibacterial chemotherapy

Sulfa drugs