Microbiology

Microbiology

Microbiology

• Microbiology is the study of microorganisms such as bacteria, viruses, protists & some fungi commonly referred to as microbes.

• These tiny organisms can only be seen with a microscope. For some (viruses for instance) only an electron microscope…

Disease

• A disease is a condition that prevents the body from functioning normally.

• Many diseases affecting humans are infectious meaning they can spread from person to person.

Pathogens

• A pathogen is a microbe that causes disease.

• Examples:– Bacteria– Viruses– Protists– Fungi

Bacteria

• Bacteria represent some of the oldest living organisms on the planet.

• They are single-celled, prokaryotic organisms.

• This means their DNA are not bound in a nucleus and they are missing some other cell structures.

Movement

• Many bacteria have flaggellum (plural flaggela) which are long, whip-like structures that act like a propeller.

• Those that do not are unable to move on their own and instead are carried by air, water currents, on organisms or objects that do move on their own, etc.

Shapes

All bacteria have one of three basic shapes:

spiral rod sphere

Energy

• Just like other living organisms, bacteria need energy for growth & repair.

• And just like other living organisms they get it either by making it from the sun, or other nutrients in their environment (autotroph) or they get it from consuming other organisms (heterotroph).

Asexual Reproduction

Asexual reproduction involves only 1 parent which produces genetically identical offspring binary fission – one cell

divides itself in 2 producing 2 identical offspring

Sexual reproduction involves 2 parents combining genetic material to produce a unique offspring conjugation – 2 bacterium

join through a thin thread-like bridge to transfer genetic material, they then separate and divide by binary fission

Sexual Reproduction

Bacterial Growth

• Many bacteria can reproduce as often as every 20 minutes, that being said…it doesn’t take long for them to increase to alarming numbers.

• Not to mention it is easy to see the evolutionary process at work since they have SO many generations in just ONE of ours.

• When environmental conditions are not favorable, bacteria will sometimes form endospores which are tiny little hardy cells that contain some genetic material.

• When conditions are favorable again the endospores will open up and begin to grow into full on bacteria.

Endospores

Good Bacteria

Most bacteria are either harmless or helpful to people. They help:• create oxygen• make many dairy products & pickles• recycle nutrients through

decomposition (remember the nitrogen cycle & the 2 types of bacteria needed for that)

• cleanup oil spills• make some medications• with your digestive process

Viruses

• Viruses are even smaller than bacteria.

• They are NOT living organisms! • The ONLY characteristic that

they share with living organisms is that they multiply BUT they can only do so with the help of a living cell, also known as a host making viruses parasitic in nature.

Size & Shape

• Viruses vary in size and shape though even the largest viruses are smaller than the smallest cells.

• They can be rod-shaped, spherical, bullet-shaped, and even complex like the bacteriophage (bacteria-eating virus).

Structure

• Regardless of the size or shape ALL viruses have 2 key components: – A protein coating– Genetic material

• The proteins on the outside match up with proteins on specific host cells. For this reason viruses can only attach themselves to specific host cells.

Reproduction• Once inside the host cell the

virus’s genetic material takes over the cell’s normal functions and instructs the cell to use its building materials to build new viruses.

• The new viruses break out when the cell dies and they move on to new cells and the process begins all over.

• Some viruses take over immediately (active), others wait for some time (hidden).

Fungi

• Fungi are eukaryotes that have cell walls.

• They are heterotrophs that feed by absorbing their food.

• They reproduce using spores.

• They need moist, warm places in which to grow. 

Food Fungi

Fungi are an important food source for humans:•Mushrooms•Bread yeast •Beer & Wine

fermentation•Blue cheese

Friendly Fungi

• Some fungi work in symbiotic relationships with other organisms.

• Over 92% of all plant species on earth have mycorrhizae fungi living on their roots that help them get nutrients out of the soil.

• Many organisms have beneficial fungi living on their skin (like humans) or in their gut.

Fungal Infections

• Not all fungi are beneficial, some are parasitic in nature.

• Keep in mind that fungi thrive in warm moist areas.

• Athlete’s Foot – from the locker room floor

• Yeast infection – when the balance of beneficial yeast is off.

• Ring worm – NOT a worm

Protists

• The kingdom protista is sort of the odds and ends kingdom for organisms that don’t fit well into the others.

• They are eukaryotic and all inhabit moist environments.

• They are mostly unicellular (single-celled).

• Categorized as: animal-like, plant-like, and fungi-like.

Animal-like Protists

• Like animals these protists, called protozoans are heterotrophs meaning that they must get their energy from another organism.

• Categorized by how they move: pseudopod, cilia, flagellum, oozing slime, via host organism.

Amoeba

• The pseudopod (pseudo = false, pod = foot) is used to help the amoeba move, and also to eat.

• It is a part of the amoeba's body that it can stretch out and pull itself with.

• To eat, the amoeba stretches out the pseudopod, surrounds a piece of food, and pulls it into the rest of the amoeba's body.

VIEW: HERE!

• When ingested by humans in contaminated food or water they can cause unpleasant diarrhea; this is known as amoebic dysentery. It is much more common in parts of the world where access to clean water is limited.

• Primary amoebic meningoencephalitis (PAM) is a rare infestation in the brain that causes death within 5 days of onset of symptoms. The offending amoeba live in very warm water and travel into the brain through the olfactory nerve.

Paramecium

• Paramecium move (and are aided in eating) with cilia which are tiny hair-like structures.

• The cilia sweep food into the oral groove which functions a bit like a mouth.

Zooflagellates

Are a class of protozoans that travel using one or more flagellum (plural: flagella) which is a long whip-like tail that propels them through the water.

Sporozoans

• A class of protozoans that travel via a host organism in a parasitic relationship.

• Example: Plasmodium that causes the disease malaria.

• The protist is transmitted from an infected person to another via the female Anopheles mosquito that lives in warm equatorial regions.

• Plasmodium requires red blood cells to reproduce, in the process destroying them.

• The destroyed red blood cells no longer serve their purpose (of caring oxygen through the body) and the debris of destroyed cells clogs up arteries.

• Left untreated it is extremely deadly.• 600,000 deaths per year are attributed to

malaria.

Fighting Malaria

• Prevention is the best strategy. That involves:– Mosquito nets– spraying insecticides– draining standing water (mosquito

breeding grounds)

• Anti-malarial drugs are available though drug resistant strains are becoming more and more prevalent.

• Insecticide resistant mosquitos are also becoming problematic.

Plant-like Protists

• Plant-like protists are so called because they are autotrophs.

• The majority of plant-like protists are algaes.

• 60% of the oxygen in the atmosphere is created by these organisms.

• Most are unicellular like diatoms

• Some are multicellular (seaweeds).

EUGLENA

VOLVOX

DIATOMS

Algae

• Algae come in a variety of sizes, shapes and colors (red, green & brown).

• Apart from creating a lot of oxygen they have other uses such as:– Food (think sushi) & food

additives (agar – thickener)– Habitats – kelp forest (brown)KELP

FOREST

Fungus-like Protists

• Like fungi, fungus-like protists are heterotrophs, absorbing their food energy from their environment (often from decaying organisms), have cell walls, and use spores to reproduce.

• The three types of fungus-like protists are slime molds, water molds, and downy mildews.

DOWNY MILDEW

SLIME MOLD

WATER MOLD

Infectious Disease

• Diseases that are spread from one organisms to another

• They are spread in 4 main ways:– Direct Contact with an infected

person

• By contaminated food & water– By indirect contact from an

infected person (airborne) or through contaminated objects (fomites)

– By contact with an infected animal

Outbreak

An outbreak is an occurrence of disease greater than would otherwise be expected at a particular time and place.

Epidemiology

• Epidemiology is the study of disease transmission (how it spreads).

• Many of this country’s epidemiologists work in Atlanta at the CDC (Centers for Disease Control).

• The first task is tracking the source of the outbreak.

• If the disease is easily transmitted and not easily treated the next step is to quarantine (isolate) the infected individuals.

Epidemic vs. Pandemic

An epidemic is an outbreak of a rapidly spreading disease.Ex: Obesity, FluA pandemic is a disease that occurs over a wide geographic area and affects a very high proportion of the population.Ex: •The Black Death in Europe in the 1300s, killed 75-200 million•Most recently HIV/AIDS & H1N1

Pathogens

The next slides are color coded by the type of pathogen (disease causing agent):• Bacteria• Virus• Fungus• Protist / parasite

Direct Contact

Examples of diseases spread by direct contact (touching, kissing, etc) with an infected individual:•Mononucleosis•Pink Eye (conjunctivitis)•Ring Worm•Chicken Pox•Cold Sores (Herpes Simplex)

Food & Water

Many pathogens that inflict serious harm on your digestive tract are spread via contaminated food or water, such as:

• Botulism• Salmonella• E. Coli• Cholera• Giardia• Amoebic dysentery• Viral Meningitis• Hepatitis A• Polio

Indirect Contact

Examples of diseases that are airborne, meaning they are spread via coughing and sneezing droplets into the air:•Cold•Flu•Whooping cough (pertussis)•Tuberculosis•Pneumonia•Meningitis (bacterial)These droplets can be inhaled directly or land on surfaces where they are picked up by unsuspecting victims.

Fomites

Fomites are inanimate objects that can become contaminated and pass diseases on from contact with them. Examples: surfaces such as floors & countertops, handles, clothing, blankets, etc.Examples of diseases that are passed only through fomites:•Tetanus•Anthrax•Athlete’s FootAny disease transmitted through contact (direct contact or by droplets/airborne) can wind up on fomites as well.

Zoonoses

Zoonotic diseases are those that can be passed from species to species such as:•Rabies•Mad Cow Disease (Bovine Spongiform Encephalopathy or BSE)•Cow pox•Hantaviruses (hemorrhagic fever)

Vectors

Many diseases are spread by animal carriers (called vectors) that are not necessarily affected by the disease.Such as:•Malaria (mosquito)•Lyme Disease (Deer Tick)•The Plague (fleas)•Many forms of Encephalitis (mosquito)•African Sleeping Sickness (tsetse fly)

Treatment

Depending on the pathogen, treatment options vary:

• Bacteria are treatable using antibiotics (so long as they are not resistant strains).

• Parasites can often be killed off using medications specifically targeted for them.

• Viruses are notoriously hard to treat, so where they are concerned PREVENTION is key and we achieve that using vaccines.

Antibiotics

• Pennecilium, a bread mold (fungus) that destroys bacterial cells was the first antibiotic to be discovered in 1928 by Alexander Fleming.

• There are now hundreds of types of antibiotics that work against different types of bacteria.

• Bacteria are becoming increasingly resistant to antibiotics due to a history of misuse.

• Each time an insufficient dose is administered the strongest bacteria survive to go on and reproduce.

Vaccines

• The first vaccine was created by Jonas Salk to combat the virus polio which was at the epidemic level in the 50s.

• The vaccine gives your body’s natural defenses (immune system) a chance to practice on an inactive or altered form of the virus.

• Vaccines are becoming increasingly controversial.

• People that are allergic to eggs or have ever had Guillain Barré syndrome (an auto-immune disease) should skip vaccination.

Biotechnology

Domestication

• Human manipulation of genes goes back as far as 12000 years ago with the domestication of cereal grains in The Fertile Crescent (between the Tigris & Euphrates Rivers in what is now Iraq).

• Domestication involves the selective breeding of plants or animals for desired characteristics.

• For instance modern corn was domesticated from an ancient wild grain that grew in Mexico called teosinte.

Gene Mapping

• A genome is the entirety of an organism’s hereditary information.

• In 1995 the first species’ (the bacterium Haemophilus influenzae) DNA was mapped in its entirety.

• Since then more than 180 more species have been mapped including humans!

• Knowing which sections of the DNA code for which traits makes choosing traits to alter or mix-and-match fairly easy.

Genetic Modification

• Genetic modification takes domestication a step further and actually allows us to select traits/characteristics based on where they are specifically within the organism’s genome.

• Examples: drought resistant corn, Round-Up Ready crops, and other Genetically Modified Foods (GMOs), GloFish

• GMOS are highly controversial.

Gene Splicing

• Gene splicing is the process of cutting a section of DNA from one organism and then inserting into the DNA of another so that that organism now has the desired trait from the other organism.

• Example: Bacteria are inserted with the gene for making human insulin and as the bacteria multiply large amounts of harvestable insulin are produced.

Cloning

• Cloning is a type of lab created asexual reproduction.

• There are 2 main types of cloning:– Reproductive cloning in which the

nucleus of a donor cell is replaced with the nucleus of a cell from the organism desired to be cloned. 22 species have been cloned to date.

– Therapeutic cloning in which embryos are created with the purpose of obtaining stem cells that can be used to treat a number of diseases.

• Cloning is quite controversial.

Agriculture

• At 7 billion, quickly approaching 9, FEEDING that many people will be a challenge.

• We know this because we can’t adequately feed the 7 billion we’ve got already.

• Increased crop yields will be necessary and that will not happen without help from the biotech industry.

• Example: developing drought tolerant plants.

Food Science

There are other ways that biotech can improve global food quality & processing such as:• Better tasting foods• More nutritious foods• Cleaner food & water• Leaner meat• Cows that produce more milk

DNA Testing

• DNA can be used by law enforcement to identify criminals.

• If the DNA at the crime scene matches (is identical) to DNA submitted by a suspect then a link can be made.

• Hair, skin cells and body fluids can be sources of evidence DNA.

• The DNA signature is obtained in a process called electrophoresis.

Medicine

• Research and developing new pharmaceuticals & vaccines.

• Researching and developing gene therapy or the use of DNA as a pharmaceutical agent to treat disease.

Bioremediation

• Bioremediation is the use of microbes to remove pollutants from the environment.

• Example: Petroleum eating bacteria that help to clean up oil spills.

Bioinformatics

Bioinformatics is the use of computers, software, and mathematical models to process and integrate biological information from large data sets.

Biotech Industry

RTP