Unit 1: Biology of Microbes that Cause Infectious Diseases (BIO205)

Included: Intro to Micro, Bacteriology, Mycology, Parasitology, Virology

Robert Koch

• Supported the "Germ Theory" by showing how anthrax was caused by a single microorganism (Isolated anthrax from an infected cow and used the isolated bacterium to infect a healthy mouse)

• Proved that microorganism was the cause of infectious disease from his experiment

• He also figured out the chain of infection

Antonie van Leeuwenhoek

The Father of Microbiology; He observed living microorganisms (both protists and bacteria) using a microscope

Francesco Redi

came up with the idea of biogenesis; (did a maggot experiment that showed that maggots were the offspring of flies and did NOT arise by spontaneous generation)

Louis Pasteur

• Showed that microbes were present in air, liquid, and solid.

• Determined that life did not arise from non-living matter

• Proposed the 'germ theory' with his yeast and bacteria experiment with wine

Florence Nightingale

Founder of Modern Nursing!

• She set standards for hygiene in military hospitals w/ public health policies

• Advocated for nursing edu.

• She wanted reform of hospitals that included public health policies (hand washing between patients)

Edward Jenner

The Father of Immunology
He developed the smallpox vaccine
(Vaccination provides protection or immunity from disease)

Contagion

"seeds of disease" (1500s)

Biogenesis

life must arise from preexisting life

Germ Theory

infectious disease is caused by microorganisms

Disease

change in health that results in the inability to carry out normal functions

Vaccination

provides protection/immunity to a disease

Cell Theory

all living things are composed of cells; they are the basic structural/organizational unit of all organisms

Koch's Postulates (step 1)

The microorganism that causes the disease must be present in every case of the disease and not be present in healthy animals. examine the patient and obtain a sample

Koch's Postulates (step 2)

The microorganism must be isolated from the diseases animal and must be grown in pure culture perform lab tests

Koch's Postulates (step 3)

The same disease must be produced when microbes from the pure culture are injected into a healthy animal or cells in the lab

Koch's Postulates (step 4)

The same microorganism must again be isolated from this "injected" diseased animal, and again be grown in pure culture perform the same lab tests to identify the same microbe

List the following organisms in order from largest to smallest: Bacteria, yeast (fungi), protozoa, viruses, helminths, arthropods/insects.

Arthropods/insects --\> helminths --\> yeast (fungi) & protozoa --\> bacteria --\> viruses

Ultra small microbes

Nanometer

Larger microbes

Micrometer

Organization of organisms

atomic --\> molecular --\> organelle --\> cellular --\> tissues --\> organs --\> organ systems --\> multi-system organisms

Types of cellular organisms

Animals, Plants, Fungi, Protists, & Bacteria

Types of acellular microbes

viruses (largest), viroids, prions (smallest)

Pathology

the study of the causes and effects of disease or injury

Do Eukaryotes have a nucleus?

Yes

Do Eukaryotes have a nucleoid?

No

What genome do Eukaryotes have?

DNA

Do Eukaryotes have cytoplasm?

Yes

Do Eukaryotes have a cytoplasmic membrane?

Yes

Do Eukaryotes have a cell wall?

No

Do Eukaryotes have a capsid coat?

No

Are Eukaryotes composed of living cells?

Yes, multicellular

Do Prokaryotes have a nucleus?

No

Do Prokaryotes have a nucleoid?

Yes

What genome do Prokaryotes have?

DNA

Do Prokaryotes have cytoplasm?

Yes

Do Prokaryotes have a cytoplasmic membrane?

Yes

Do Prokaryotes have a cell wall?

Yes

Do Prokaryotes have a capsid coat?

No

Are Prokaryotes composed of living cells?

Yes, unicellular

Do Viruses have a nucleus?

No

Do Viruses have a nucleoid?

No

What genome do Viruses have?

DNA or RNA

Do Viruses have cytoplasm?

No

Do Viruses have a cytoplasmic membrane?

No

Do Viruses have a cell wall?

No

Do Viruses have a capsid coat?

Yes

Are Viruses composed of living cells?

No!

General Structure of a bacterial cell

Streptococcus

chains of spherical shaped bacteria

Staphylococcus

cluster of spherical shaped bacteria

Spirillum

spiral shaped bacteria

Streptobacilli

chains of rod shaped bacteria

Vibrio

curved rod shaped bacteria

Bacillus

Rod shaped bacteria

Diplococci

spherical bacteria that grow in pairs (two)

Bacteria

smallest living organism

What is the function of the flagella?

allow movement of the bacteria similar to a propeller on a boat or swimming (ex: sperm)

4 types of flagellar arrangements

monotrichous, lophotrichous, amphitrichous, peritrichous

Flagella

long, whip-like protein appendages that allow propeller-like movements of bacteria

fimbriae or pili

short, fingerlike protein projections that aid in bacteria cell attachment specific host membrane receptors

Sex pili

assist in transfer of genetic material between cells (conjugation)

What process are fimbriae and sex pili involved in?

Bacterial Conjugation (attachment to surface and motility)

Biofilms

living layers of bacteria (ex: plaque on teeth, indwelling medical implants)

Glycocalyx

sticky covering composed of polysaccharides & proteins (2 forms: rigid capsule & loose single layer
Function \= aid in formation of biofilms, protection, attachment to surfaces(dental plaque), storage, and inhibits phagocytosis

Does gram-negative have a thin or thick layer of peptidoglycan?

Thin

Does gram-negative have an outer membrane?

Yes

Does gram-negative have mycolic acid (wax)?

No

Does gram-negative have proins?

Yes

Does gram-negative have LPS or teichoic acid?

LPS

What color does gram-negative stain?

Pink

Does gram-positive have a thin or thick layer of peptidoglycan?

Thick

Does gram-positive have an outer membrane?

No

Does gram-positive have mycolic acid?

No

Does gram-positive have porins?

No

Does gram-positive have LPS or teichoic acid?

Teichoic acid

What color does gram-positive stain?

Purple

Does acid fast have a thin or thick layer of peptidogylcan?

Thick

Does acid fast have an outer membrane?

No

Does acid fast have mycolic acid?

Yes

Does acid fast have porins?

No

Does acid fast have LPS or teichoic acid?

Teichoic acid

What color does acid fast stain?

Fuchsia

Gm - vs. Gm + cell wall structure

Function of Plasmids

carry genes for antibiotic resistance

Peptidoglycan cell wall

surrounds cell membrane & provides shape, support, and protection from osmotic pressure

Teichoic acids

polysaccharide molecules attached to outer surface of cell

The structure and function of endospores

• 3-layer structure consisting of peptidoglycan, calcium, and a coat containing a keratin-like protein

• The overall function is long term storage & protection of genetic material

Process that endospores are formed

Formed due to lack of moisture or nutrients during sporulation (one spore per cell)... Sporulation steps:
1.) axial filament formation
2.) asymmetric cell division
3.) forespore engulfment
4.) cortex formation
5.) spore coat synthesis
6) Spore maturation and mother cell lysis
7.) free endospore

Gram-negative bacteria example

Staphylococcus aureus

Gram-negative bacteria example

Escherichia coli (E.coli)

Acid-Fast bacteria example

Mycobacterium tuberculosis

Heterotrophic

to obtain food from other sources

Dimorphic

have 2 forms (yeast and mold)

Bud scars

crater-like rings of scar tissue formed after newly emerged daughter yeast cell separates from the mother cell

Hyphae

long branching chains for cells

Mycelium

a visible mass of hyphae

Fungal spores

microscopic particles that allow fungi to reproduce

Binary Fision
(asexual reproduction)

bacterial cells splits into 2 identical copies called clones (parent cell --\> 2 daughter cells)ff

Do bacteria have a nucleus?

No

Are bacteria prokaryotic or eukaryotic?

Prokaryotic