Prescott's Microbiology Chapter 1

Viruses

Acellular entities that must invade a host cell to multiply.

The Three Domains of Life

Bacteria Archaea Eukarya

Francesco Redi

Carried out experiments on decaying meat and its ability to produce maggots.

Divisions and Types of Microbes

Cellular (fungi, protists, bacteria, and archaea) and acellular (viruses, viroids, satellites, and prions)

Modern Vs. Ancient (RNA)

Cellular pool of RNA in modern day cells exists in and is associated with the ribosome (rRNA, tRNA, and mRNA). --RNA catalytic in protein synthesis --RNA may be precursor to double stranded DNA. ATPis the energy currency and is a ribonucleotide. RNA can regulate gene expression.

Felix Pouchet

Claimed in 1859 to have carried out experiments conclusively proving that microbial growth could not occur without air contamination.

Satellities

Composed of a nucleic acid enclosed in a protein shell. They cause plant diseases and animal diseases (ex: hepatitis).

Louis Pasteur

Ended the debate with his famous swan-neck flask experiment, which allowed air to contact the broth

What is an attenuated vaccine

is a vaccine created by reducing the virulence of a pathogen, but still keeping it viable (or "live").

Describe a spirochete?

is any of a group of spiral-shaped bacteria, some of which are serious pathogens for humans, causing diseases such as syphilis, yaws, Lyme disease, and relapsing fever.

Parts of the microscope

1. Arm - all other parts are attached to it 2. Base - bottom 3. Stage - platform that holds the slide 4. Mechanical stage - device used to clamp slides to the stage - allows the slide to be moved 5. Light source - provides illumination and is located in the base 6. Voltage control - varies the intensity of light; light will last longer if the voltage control is kept on low 7. Lens system 8. Focusing knobs 9. Ocular adjustment 10. Ocular - eyepiece (10X); has 2 or more lenses 11. Condenser - under the stage; collects and directs the light; concentrates the light for uniform illumination.

Algae

A type of protist. They are photosynthetic combined with cyanobacteria. They produce 75% of the plants oxygen.

Microbiology

A branch of biology dealing especially with microscopic forms of life (generally < 1mm, some macroscopic; as bacteria, protozoans, viruses, and fungi).

Fungi

A diverse group of microorganisms that range from unicellular fungi (molds/mushrooms) that form thin, threadlike structures called hyphae.

Bacteria

A member of a large group of unicellular microorganisms that have cell walls but lack organelles and an organized nucleus, including some that can cause disease.

Pure Culture

A population of cells that are identical because they arise from a single cell.

Strain

A population of organisms that descends from a single organism or pure culture stain.

Hydrogenosomes

Analogous to mitochondria; can make hydrogen without oxygen Part of endosymbiotic hypothesis

Microorganisms

Algae Fungi Protist Bacteria

Theodore Schwann

Allowed air to enter a flask containing a sterile nutrient solution after the air had passed through a red hot tube.

George Friedrich Schroder & Theodore Van Dusch

Allowed air to enter a flask of heat sterilized medium after it had passed through sterile cotton wool, no growth occurred.

Eukaryotic Cells

An organism whose cells contain a nucleus surrounded by a membrane and whose DNA is bound together by proteins (histones) into chromosomes.

Universal Phylogenetic Tree

Based on comparisons of small subunit rRNA (SSU rRNA). Aligned rRNA sequences from diverse organisms are compared and differences counted to derive a value of evolutionary distance. Relatedness, but not time of divergence, determined this way.

Pasteur

Developed an attenuated anthrax vaccine.

Joseph Lister

Developed antiseptic surgery and transformed surgery.

Archaea

Distinguished from bacteria by their distinctive rRNA sequences, lack of peptidoglycan in cell walls. extreme temperatures

Indirect Evidences (Origins of Life)

Finding ancient characteristics in extant microorganisms. Microbial fossil record is not reliable (archaeon Apex Chert) Molecular fossils such as hopanes (bacterial lipid found in plasma membrane)

Agostino Bassi

Found that silkworm disease was due to fungal infection.

All cells have

Genetic Information Cytosol Cell Membrane

Species

Groups of interbreeding or potentially interbreeding natural populations that are reproductively isolated.

Prokaryotic Cells

Have an open floor plan. Their contents are not divided into compartments by membranes.

Antony Van Leeuwenhoek's contribution to microbiology?

He was one of the first people to observe microorganisms using a microscope of his own design.

Robert Hooke's contributions to microbiology?

He was the first to use an microscope to observe living things.

Microorganism

Organisms too small to be seen by the unaided eye. Most populous and diverse groups of organisms. Found everywhere on the planet. Play a major role in recycling essential elements.

Earliest Molecules (RNA)

Original molecule must have fulfilled protein and hereditary function. Ribozymes --RNA molecules that form peptide bonds. --Perform cellular work and replication Earliest cells may have been RNA surrounded by liposomes.

Eukarya

Includes microorganisms classified as protists or fungi.

Prions

Infectious agents composed only of protein, and are responsible for causing a variety of spongiform encephalopathies.

Viroids

Infectious agents composed only of ribonucleic acid (RNA). They cause numerous plant diseases.

Functions of capsules

It enhances the ability of bacteria to cause disease, and it can protect cells from engulfment by eukaryotic cells, such as macrophages. ... they also contain water which protects the bacteria against desiccation.

Evolution of Cellular Microbes

Mutation of genetic material led to selected traits. New genes and genotypes evolved - producing mosaic of genetic information. Bacteria and Archaea increase genetic pool by horizontal gene transfer within the same generation.

Pasteur

Prepared a rabies vaccine.

Slime Molds

Protists that behave like protozoa in one stage of their life cycle but like fungi in another. -have two life cycle stages

Water Molds

Protists that grow on the surface of freshwater and moist soil.

M.J Berkeley

Proved the great potato blight of ireland was caused by water mold.

Lazzaro Spallanzani

Sealed glass flasks the contained water and seeds and then placed the flasks in boiling water for 45 minuets. He found no growth took place as long as the flasks remained sealed.

Germ Theory

States that many diseases are caused by microorganisms.

John Needham

Suggested that the organic matter in these extracts contained a vital force that could confer the properties of life on nonliving matter.

Spontaneous Generation

That living organisms could develope from nonliving matter, as inferred from the apparent appearance of life in some supposedly sterile environments

Koch's Postulates

The bacteria must be present in every case of the disease. The bacteria must be isolated from the host with the disease and grown in pure culture. The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.

How are microbes named?

The genus and specific epithet. The genus is capitalized and the specific epithet is lowercase. EX: Ecoli

Koch's fourth postulate

The pathogen must be isolated from the inoculated animal and must be shown to be the original organism.

Last Universal Common Ancestor

The root or origin of modern life is on bacterial branch, but nature still controversial. Archea and Eukarya evolved independently of bacteria. Archea and Eukarya diverged from common ancestry.

Koch's third postulate

The same disease must result when the isolated microorganism is inoculated into a healthy host

Koch's first postulate

The same pathogen must be present in every case of the disease

Microbiology

The study of organisms too small to be seen with the naked eye.

Koch's second postulate

The suspected pathogen must be grown in pure culture

Why doesn't viruses fit into any of the 3 domains of life?

They're not living because they can't replicate without a hostile takeover of a living host cell.

Protozoa

Unicellular animal like protists that are usually motile.

Protists

Unicellular but larger than most bacteria and archaea. Include algae, protozoa, slime molds, and water molds.

The 4 acellular infectious agents

Viruses Viroids Satellites Prions

Louis Pasteur

designed an experiment to test whether sterile nutrient broth could spontaneously generate microbial life. To do this, he set up two experiments. In both, he added nutrient broth to flasks, bent the necks of the flasks into S shapes, and then boiled the broth to kill any existing microbes.

Robert Koch

developed ways of staining bacteria to improve the bacteria's visibility under the microscope, and were able to identify the bacterial causes of tuberculosis (1882) and cholera (1883).

John Tyndall and Ferdinand Cohn

discovered that different broths need different boiling times to be sterilized. Tyndall discovered that bacteria exists in two forms, ones that are killed by heat, and heat-resistant bacteria. cohn discovered endospores, and Koch discovered anthrax.

Function of Membrane proteins

relay signals between the cell's internal and external environments.