Main Themes of Microbiology

BIO 370 Microbiology

Dr. Ramos

What is a microorganism?

• Microscopic organisms

• Ubiquitous

• Different types– Bacteria

– Viruses

– Fungi

– Protozoa

– Algae

– Helminths

Origin of Microorganisms• Fossil record

– Early microorganisms

• Small, simple

• Lack of specialized internal structures

• Prokaryotics

– Eukaryotics

– Endosymbiosis

What are some of the differences between eukaryotic and prokaryotic

organisms?

Microorganism Diversity

• There are 10 million species of prokaryotes.

• There are over 3600 known viruses.

• There are over 70,000 describes species of fungi.

Is a virus a cell?

• Small particles

• Between cell and large molecules.

• Small amount of hereditary material wrapped in a protein covering.

– DNA

– RNA

• Large impact on hosts.

What is your experience with microorganisms?

How do we use microorganisms?Why should we study them?

Branches of MicrobiologyLargest and most complex area of biological

sciences

• Agricultural microbiology

• Biotechnology

• Food, dairy, and aquatic microbiology

• Genetic engineering and recombinant DNA technology

• Public health microbiology and epidemiology

• Immunology

• Many, many more

Sub-Disciplines of Microbiology

• Microbiologists are sometimes referred to by the type of microbial system that they study

• Bacteriology: Study of prokaryotes

• Mycology: Study of fungi

• Phycology: Study of algae

• Protozoology: The study of protozoa

• Virology: The study of viruses

• Immunology: The study of the immune system

Importance of Microbes

• The study of microbiology is relevant to our everyday life in many different ways.

1.Microbes are the earliest organisms found in the fossil record (survival, adaptation and evolution)

2.Microbes are ubiquitous (found nearly everyway)

3.They perform essential reactions in the environment

4.Microbes can be harnessed to work for us

5.They sometimes cause infectious diseases

Ubiquity of Microorganisms• Found nearly everywhere

• Occur in large numbers

• Live in places many other organisms cannot

– Earths crust, polar ice caps, bodies of plants and animals

Microbes in the Environment

• Microbial photosynthesis (CO2 ---light organic mat’l) account for most of the atmospheric oxygen on Earth– Anoxgyenic, Oxygenic (70% oxygen)

• Microbes are essential for decomposition of dead organisms into simple compouns

• Many biologically important elements (S, N, P) are cycled by microbes = nutrient recycling – Gas production, carbs in cattle

Human Use of Microorganisms

• Humans have been using microorganisms for thousands of years– Baker’s and brewer’s yeast

– Sugar Alcohol in wine and beer

– Cheeses

– Moldy bread on wounds

– Extraction of copper from ore (top)

– Synthesis of drugs, hormones and enzymes (mid)

Harnessing the Power of Microbes

• Can be used to make or preserve food products (e.g. yogurt, salami, cheeses)

• Can produce important compounds (e.g. antibiotics, MSG, ethanol)

Biotechnology• Biotechnology- when humans manipulate

microorganisms to make products in an industrial setting– Genetic engineering

• create new products and genetically modified organisms (GMOs)

– Recombinant DNA technology• allows microbes to be engineered to synthesize desirable

proteins (i.e. drugs, hormones, and enzymes)

– Gene therapy• replaces missing parts of defective genes in human cells

through genetic engineering

Bioremediation

• Bioremediation- use of microbes to restore stability or clean up toxic pollutants

– Oil spills

– Chemical spills

– Water and sewage treatment

History of Microbiology

• Key to the study of microorganisms was the development of…

History of Microbiology• Earliest record of microbes was from the work of

Robert Hooke in the 1660’s

Cell

History of Microbiology• The most careful observations of microbes was

possible after Antonie van Leeuwenhoekcreated the single-lens microscope.

• Known as the father of bacteriology and protozoology

• Described:• Algae• Sperm• Erythrocytes• Muscular fibers• Bacteria

Spontaneous generation• For many centuries many people believed in the

concept of spontaneous generation, the creation of life from organic matter.

• Francesco Redi disproved spontaneous generation for large organisms by showing that maggots arose from meat only when flies laid eggs in the meat.

Spontaneous generation

• Spontaneous generation for small organisms again gained favor when John Needham showed that if a broth was boiled (presumed to kill all life) and then allowed to sit in the open air, it became cloudy.

Spontaneous generation

• Louis Pasteur ended the debate with his famous swan-neck flask experiment, which allowed air to contact the broth. Microbes present in the dust were not able to navigate the tortuous bends in the neck of the flask.

Scientific Method

• Inductive reasoning

• Hypothesis

• Theory

• Law

Development of Medical Microbiology

Development of Medical Microbiology

Discovery of Spores and Sterilization

• John Tyndall

– High resistance to heat

– Vigorous treatment

• Ferdinand Cohn

– Spores

– Sterile

Aseptic Technique

• Poisonous vapors

• Variety of scientists linked microscopic organisms with disease.

• Hospital induced infections

• Joseph Lister

– Disenfecting hands

– Disenfecting air

Germ Theory of Disease

• Louis Pasteur

– Vaccine development (anthrax and rabies)

– Role of microbes in wine and beer fermentation

– Pasteurization

First studies to show human diseases could arise from infection.

Koch’s Postulates

• The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms.

• The microorganism must be isolated from a diseased organism and grown in pure culture.

• The cultured microorganism should cause disease when introduced into a healthy organism.

• The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.

Taxonomy: Naming, Classifying, and Identifying Microorganisms

• Microbial nomenclature- naming microorganisms

• Taxonomy- classifying living things

• Originated over 250 years ago with the work of Carl von Linné

• Identification- discovering and recording the traits of organisms so they can be named and classified

• Levels of Classification – Dear King Philip Came Over From Germany Saturday

Simple Taxonomy

Assigning Specific Names

• A standardized nomenclature allows scientists from all over the world to exchange information

• The binomial system of nomenclature

– The generic (genus) name followed by the species name

– Generic part is capitalized, species is lowercase

• What constitutes a species?

– Both are italicized or underlined if italics aren’t available

– Staphylococcus aureus

Naming Examples

• Staphylococcus aureus

– staphule- bunch of grapes, kokkus- berry, aureus - golden

• Campylobacter jejuni

– kampylos-curved, bakterion- little rod, jejunum- part of intestine

• Giardia lamblia

– Alfred Giard- Fr. Microbiologist, Victor Lambl – Bohemian physician

• After first use, scientific names may be abbreviated with first letter of genus and full species epithet (Ex. E. coli)

Levels of Classification• Domain

• Kingdom

• Phylum or division

• Class

• Order

• Family

• Genus

• Species

The Origin and Evolution of Microorganisms

• Phylogeny- the degree of relatedness between groups of living things

• Phylogeny usually represented by a tree-showing the divergent nature of evolution

The Origin and Evolution of Microorganisms

• Based on the process of evolution- hereditary information in living things changes gradually through time; these changes result in structural and functional changes through many generations

• Two preconceptions:– All new species originate from preexisting species

– Closely related organisms have similar features because they evolved from a common ancestor

OLD - The Five Kingdom ModelRobert Whittaker

(1959)

1. Animals

2. Plants

3. Fungi (microbes)

4. Protists (microbes)

5. Monera (microbes)

New Views of Phylogeny• Carl Woese (1975)

• Used 16S rRNA

• Three “Domains”1. Archaea

(all microbes)

2. Bacteria (all microbes)

3. Eukarya (some microbes)

You should be able to…• List the various types of

microorganisms

• Describe the role and impact of microbes on Earth

• Explain the theory of evolution and why it is called a theory.

• Explain the ways that humans manipulate organisms for their own uses.

• Summarize the relative burden of human diseases caused by microbes

• Differentiate between prokaryotic and eukaryotic microorganisms

• Identify a third type of microorganism (other than prokaryote and eukaryote)

• Make a timeline of the development of microbiology from the 1600s to today

• Explain what is important about the scientific method

• Correctly write the binomial name of a microorganism