MicrobiologyThe early years Medical Microbiology Antoni van Leeuwenhoek

Microbiology—The early years Medical Microbiology

Antoni van Leeuwenhoek 1632– 1723 • Father of _____________ • Dutch tailor, merchant, and lens grinder • Created his own magnifying _______ to examine the quality of cloth • Looked at a drop of water through his lens and discovered microorganisms (microbes) – All organisms too small to see without a microscope • Invented the first _________ • The only microbe that van Leeuwenhoek didn’t see was a ________

How are Microorganisms classified? • Carolus Linnaeus (1707– 1778) developed a ______________—a system for __________ plants and animals and grouping similar organisms together. (either animal or plant) • Now there are 6 categories: – – – ________________ Archaea ________________________________ Algae small multicellular animals.

Bacteria and Archaea • Prokaryotes—cells lack a ____________ • _____________ reproduction • Bacteria may or may not have a ___________ • Archaea live in _____________ environments and do not cause disease (acidic hot springs) • Most bacteria do NOT cause disease and are _______________ to humans – Break down dead plants and animals

Streptococcus bacteria Nucleus of cheek cell Cells of the bacterium Streptococcus (dark blue) and two human cheek cells

Fungi • ____________(cells have a nucleus) • Are not plants – Do not ____________ their own ________ • Are not animals – Have _______________ • Molds and yeasts – Molds—multicellular, reproduce using ______ • “cottony” growths on cheese and bread • Penicillum chrysogenum—mold that produces __________________ – Yeasts—unicellular, reproduce by ___________

Protozoa • Eukaryotes • Most are capable of _____________ • Plasmodium—protozoa that causes malaria • Protozoa typically live freely in __________, but some live inside ______________, where they can cause disease. • Most protozoa reproduce asexually, though some are sexual as well.

Pseudopodia (Amoeba proteus) • _______________— extensions of a cell that flow in direction of travel pseudopodia nucleus

Cilia (Euplotes) • _________—hair-like, beat rhythmically for cell movement

Flagellum (Perenema) • ______________– longer and fewer in number than cilia, whip-like

Algae • Unicellular or multicellular • Use _______________ – Make food from ____________and ______ using energy from ______________ • Different from plants due to ________________________ __ • ______________—seaweed and kelp • Unicellular algae—live in ___________and in _____________ – Provide most of the world’s ___________ through photosynthesis

Parasitic Worms • Range from microscopic to 23 ft long tapeworms • Infections are diagnosed by finding microscopic ___________ and immature parasites in _________, _________ and lymph specimens. Erythrocyte (RBC)

Viruses • Not discovered until the invention of the ___________________ __in 1932 • _______________ parasite – Made up of DNA or RNA surrounded by a protein coat

virus bacterium Viruses assembling inside the cell

Spontaneous Generation? • Scientists believed that microorganisms could be spontaneously created out of inanimate objects for 2000 years—Aristotle • Disproved by Louis Pasteur in the 1800’s Francesco Redi disproved spontaneous generation for large organisms by showing that maggots arose from meat only when flies laid eggs in the meat.

Louis Pasteur’s swan necked flasks Pasteur filled a flask with medium, _________ to kill all life, and then drew out the neck of the flask into a long S shape. This prevented microorganisms in the air from easily entering the flask, yet allowed some air interchange. If the swan neck was broken, microbes readily entered the flask and grew.

Pasteurization • Pasteur was asked the question, ” Why does beer and wine become sour? ” • Pasteur discovered that ________, rather than air, converted the sugars in beer and wine into alcohol – ______________ • He heated the wine just enough to kill the bacteria and prevent spoilage – _______________ – What other fluids are pasteurized?

Germ theory of disease • Prior to Pasteur, people believed that disease was a result of ____________ by God or demons • The germ theory states that ______________ are the cause of most diseases. • Robert Koch—proved that bacteria causes diseases – Koch discovered rod -shaped bacteria now known as Bacillus anthracis in the blood of cattle that had died of anthrax. – He cultured the bacteria on nutrients and then injected samples of the culture into healthy animals. – When these animals became sick and died, Koch compared both blood samples and found that the two sets of blood cultures contained the same bacteria.

Koch’s postulates • Koch's research provides a framework for the study of the etiology of any infectious disease. • The ________ pathogen must be present in every case of the disease. • The pathogen must be __________ from the diseased host and grown in __________ culture. • The pathogen from the pure culture must _________ the disease when it is inoculated into a healthy, susceptible laboratory animal. • The pathogen must be isolated from the inoculated animal and must be shown to be the original organism.

Vaccinations • Edward Jenner—_________ vaccine 1796 • The protection from disease provided by vaccination (or by recovery from the disease itself) is called ______________. • Vaccines are made from: – ____________ viruses produced in a lab – ______________ viruses – parts of viruses – __________________.

Chemotherapy—the search for the magic bullet • Chemotherapy—treatment of disease using _____________ – Also the treatment of cancer using chemicals • _____________—chemicals produced by bacteria and fungi to combat other microorganisms • The success of chemotherapy is based on the fact that some chemicals are more ____________ to microorganisms than to the hosts infected by the microbes. • In 1910, Paul Ehrlich theorized about a “magic bullet" that could hunt down and destroy a pathogen _________________the infected host.

It’s okay to be a slob sometimes… • In 1928, Alexander Fleming noticed that, in the areas where mold contaminated his culture plates, bacteria would not grow. • The bacteria was identified as _________________ • The bacterial inhibitor was named ______ • The medication Penicillin was not manufactured and distributed until 10 years later. • The antibiotic challenge: create a medication that will __________the microorganism, but won’t harm the host.

Penicillin contaminated agar plate