Chapters 20,21,22Microbiology

Microorganisms

VirusesNonliving or Living?

• Prokaryotes• Bacteria

• Eukaryotes• Protists• Fungus

Viruses• Living because they reproduce• Nonliving because…– Require a host aka Parasitic– Replicate instead of reproduce

• Sizes:– Smaller than monerans (Bacteria)

• Almost all organisms have one virus that infects them.

• They are “host-specific” meaning that they will usually only infect 1 organism.

This is what we consider them to be in this class!

Viral Parts• Capsid: outer

protein coat• Genetic Material:

DNA or RNA• Envelope:

Protective layer around the capsid.– NOT ALL VIRUSES

HAVE THESE– Comes from the

host cell membrane

Viral Shapes• Spiral,

polygons, rods, bullet, needle

• Bacteriophage

Types of Viruses• Bacteriophages– Infect Bacteria

only

Types of Viruses• DNA Viruses– Has DNA as

Genetic MaterialSingle-stranded DNA virus:Canine Parvovirus

Double-stranded DNA virus:Chicken pox (Varicella zoster)

DNA Viruses

Herpes Virus in a host cell

Human Papilloma virus: causes warts

Adenovirus: causes some colds

RNA viruses

Paramyxovirus: Measles and Mumps (in a host cell)

Rabies virus

Rhinovirus: Common ColdHas RNA as Genetic

Material

Types of Viruses• Retroviruses- RNA as genetic

material.– To replicate, they convert RNA to DNA

and then use host to make more RNA.HIV (Human immunodeficiency virus)

Characteristics of Bacteria (Monerans)

• All are prokaryotic• All have a cell wall• All have DNA as genetic material• All have ribosomes, and no other

organelles• All are unicellular• Most are heterotrophic (not all!), some

are chemo or photo-autotrophic

Shapes• Coccus: Round bacteria• Example: Staphylococcus sp.

Shapes• Bacillus: rod bacteria– Example: Bacillus anthracis

Shapes• Spirochetes: spiral bacteria– Example: Treponema pallidum

Fungus Characteristics• Eukaryotes• Heterotrophic

decomposers– Saprophytes,

parasites, predators, mutualistic

• Non-motile

• Cell walls of chitin• Most have hyphae that into tangled

masses called mycelium• Growth occurs rapidly at tips

General Characteristics of Protists

• Have a nucleus• Are grouped based on the method of

locomotion– Cilia– Flagella– Pseudopods– Non-motile

3 Groups1. Protozoans– animals

2. Algae– plants

3. Molds– fungus

Viral• Cystic

fibrosis treatment

• Tulip colors• Treat

bacterial diseases ***

• Genetic engineering ***

Bacteria• Fix nitrogen• Decomposer• Food

production• Sewage

treatment• Antibiotics• Genetic

engineering

Fungus• Mutualism• Decomposer• Antibiotics• Fermentation• Food

production

Protists• Producers in

water• Oxygen

production

Microorganism benefits

Viral• Disease• Cancer

Bacteria• Disease• Spoilage

Fungus• Disease• Spoilage

Protists• Disease• Algal

blooms

Microorganism disadvantages

What do microorganisms need?• Each species has an OPTIMUM– Temperature– pH– Air– Osmotic Pressure–Water– Nutrients

How can we prevent them from getting these requirements?

• Heat• Change pH• Add salt or sugar• Remove oxygen (canning)• Remove water by

Dehydrating foods

How do we spread diseases and how do we stop them?

• Five methods for spreading disease.– AIR– FOOD–WATER– PERSON to PERSON– VECTORS- insects

How does an infection makes us sick?

• What they do: Grow and Reproduce– Destroys cells– Release toxins– Block passages

• What we do: – Crummy Article

Germ Theory of Disease 1857Louis Pasteur• Eliminates theory of spontaneous

generation• Saves the wine Industry in France• Proposes that there is a relationship

between a microorganism (pathogen) and a disease

• Develops– Pasteurization– Vaccines for anthrax and rabbies

Koch’s Postulates 1876Find suspect organism

Isolate suspect and grow in pure culture

Inject pure culture into healthy subject and get the same disease symptoms

Re-isolate the same suspect organism and grow it in pure culture

Va

ccines:

• Treatment for viruses

• Taken as a preventative method

• Cannot help you once you have the disease

• Viruses can become resistant to these, but it is not usually a fast process

• Human production Antibioti

cs: • Treatment for

bacterial infections• Taken once you

have the disease• Cannot be used as

a preventative• Bacteria can easily

become resistant to these

• Bacteria and some fungi produce these

Vaccines• Involves your immune system being

stimulated• Dead or weakened antigen (foreign

particle)• Engulfing cells and antibody producing cells

destroy the antigen• Memory cells prepare for another infection– Response to virus is faster and stronger the

second time• Adds to the health of the community

Antibiotics• Work ONLY on bacteria– Bacteria are prokaryotic, we are eukaryotic– Bacteria have a cell wall, we do not.

• These help, but our immune system still has to “clean-up”

• Examples:– Penicillin – stops cell wall formation– Tetracycline – stops protein synthesis– Ciprofloxacin – stops DNA replication

Proper use of antibioticsPrevents Resistance

Only taking them for bacterial infections

Taking pills on time

Taking all your

prescription

Concentration of Bacteria at which you feel better =====

Time in DaysShot of Penicillin-Pill taking intervals – missed interval

Concentration of antibiotic - Effective concentration of antibiotic ---Concentration of bacteria ……

Conc

entra

tion

Antibiotic Resistance• Development of Resistance

– Alter the antibiotic– Alter the target or structure– Pump out the antibiotic

• Developing new anti-resistance antibiotics– Target the mechanism that confers resistance

• Stop alteration of antibiotic• Stop alteration of target• Stop the molecular pumping mechanism

Stop the Spread of antibiotic resistance

Do not demand antibiotics

Take them exactly as prescribed

Wash fruits and vegetables(no such thing) thoroughly; avoid raw eggs and undercooked meat, especially in ground form

Use soaps and other products with antibacterial chemicals only when protecting a sick person whose defenses are weakened

The BIG picture• Diet• Rest• Exercise both aerobic and resistance

• Personal Cleanliness e.g. wash your hands• Proper Preparation and storage of food

– It Must Have Been Something You Ate• Environmental Cleanliness pollution, filth• Annual Physical

Big Picture cont…• Report symptoms promptly to a

responsible person• Follow physicians instructions– antibiotics

• Vaccinations: Vital– The Vaccine Conundrum