Introductory Microbiology Dr. Heather Townsend

Characteristics of Life Growth and development Reproduction and heredity Metabolism Movement and/or irritability Cell support, protection, and storage mechanisms Transport of nutrients and waste Living things are made of cells!!

All cells……. Have an outer plasma membrane Contain DNA Enclosed within the cell somewhere Contain cytoplasm Everything between the plasma membrane and the region of DNA Gives cells their shape Assist in movement of cell and organelles

Characteristics of Microbes Prokaryotic cells Smaller Lack special structures such as a nucleus and organelles All prokaryotic cells are microorganisms Some microorganisms are eukaryotic Viruses?

“Micro”organisms

Characteristics of Cells Eukaryotic cells Animals, plants, fungi, and protists contain double-membrane bound nucleus with DNA contain membrane-bound organelles 10–100 µm in diameter

Characteristics of Cells Prokaryotic cells ~1.0 µm in diameter Bacteria and archaea no nucleus no membrane-bound organelles

Microbiology The study of of organisms (microorganisms or microbes) too small to be seen without magnification This includes: Bacteria Viruses Fungi Protozoa Helminths (worms) Algae

Klebsiella pneumoniae, bacteria that causes pneumonia in humans The Microbes 1. Bacteria Single-celled organisms Various shapes Spherical Rod Spiral shapes Cellular Lack membrane-enclosed cellular structures Widely distributed in nature Klebsiella pneumoniae, bacteria that causes pneumonia in humans

The Microbes 2. Viruses Acellular Composed of nucleic acid and a few proteins Replicate themselves to display other properties of living organisms when they invade living cells

The Microbes 3. Fungi Yeasts and molds Mushrooms Single-celled, microscopic Mushrooms Multicellular, macroscopic Cell nucleus and other cellular structures Absorb nutrients from their environment Widely distributed in water and soil Act as decomposers of dead organisms The Microbes

The Microbes 4. Protozoa Single-celled, microscopic organisms Have at least one nucleus and many cellular structures Obtain food by engulfing or ingesting smaller organisms Most can move Found in many different environments The Microbes Amoeba

The Microbes 5. Helminths Large, multicellular Parasitize host tissues Organs for reproduction, digestion, movement, protection Mouthparts Ingestion of larvae or eggs in food Tapeworm Head

Micrasterias, a green algae living in The Microbes 6. Algae Single-celled microscopic organisms Have a nucleus and many membrane-enclosed cellular structures Photosynthesize their own food Widely distributed in fresh and salt water Important source of food for other organisms Micrasterias, a green algae living in fresh water

General cell characteristics Locomotor appendages External boundaries

External Structures of Cells Locomotor appendages flagella long, sheathed cylinder containing microtubules covered by an extension of the cell membrane function in motility cilia similar in overall structure to flagella shorter and more numerous found only on a single group of protozoa and certain animal cells function in motility, feeding and filtering

External Boundary Structures Plasma (cell) membrane typical bilayer of phospholipids and proteins serves as selectively permeable barrier in transport

External Structures of Cells Glycocalyx an outermost boundary that comes into direct contact with environment usually composed of polysaccharides appears as a network of fibers, a slime layer or a capsule functions in adherence, protection, and signal reception Beneath the glycocalyx: Fungi and most algae - cell wall Protozoa, a few algae, and all animal cells – cell membrane

External Boundary Structures Cell wall Fungi thick inner layer of polysaccharide fibers composed of chitin or cellulose and a thin layer of mixed glycans Algae varies in chemical composition substances include cellulose, pectin, mannans, silicon dioxide, and calcium carbonate Bacteria!!! Dependent on cell wall composition

Prokaryote Eukaryote

Branches of Study Within Microbiology Immunology: studies immune chemicals and cells that are produced in response to infection Public health microbiology & epidemiology: aim to monitor and control the spread of diseases (CDC) Food, dairy and aquatic microbiology: examine the ecological and practical roles of microbes in food and water Biotechnology: ranges from bread making to gene therapy Genetic engineering & recombinant DNA technology: altering the genetic makeup of organisms

Microbes Are Involved In: nutrient production & energy flow i.e., photosynthesis decomposition and nutrient recycling production of foods, drugs & vaccines bioremediation causing disease

Impact of Pathogens Pathogens Diseases-causing agents Nearly 2,000 different microbes cause diseases in the human body 10 B infections/year worldwide 13 M deaths from infections/year worldwide killing about 1/3 of the U.S. population each year

Impact of Pathogens Emerging diseases Reemerging Becoming more prominent over the years Zoonosis SARS Reemerging Older diseases increasing in occurrence TB Malaria Hepatitis

Historical Microbiology 1546 – physician suggest that invisible organisms may be involved with disease Abiogenesis vs biogenesis

Antonie van Leeuwenhoek First to observe living microbes His single-lens magnified up to 300X (1632-1723)

Early Medical Microbiology Spontaneous generation “Living things arise from nonliving things” Belief that some forms of life could arise from vital forces present in nonliving or decomposing matter Debate over spontaneous generation led in part to development of scientific method

Early Medical Microbiology Louis Pasteur: Worked in the wine industry Had knowledge about yeast producing alcohol Swan-neck flasks Tipping the flask would allow the microbes to enter the infusion Cause them to become cloudy Main experiment that helped disprove spontaneous generation Developed Pasteurization Developed a rabies vaccine

Early Medical Microbiology Robert Koch (~120 years ago, German) Linked a microscopic organism with a specific disease (anthrax) Developed method to grow bacteria in pure cultures (cultures containing only one kind of organism) Used solidified gelatin from potato slices mixed with agar Creates a firm surface that microbes could grow on

Koch’s Postulates The specific causative agent must be found in every case of the disease The disease organism must be isolated in pure culture Inoculation of a sample of the culture into a healthy, susceptible animal must produce the same disease The disease must be recovered from the inoculated animal

Early Medical Microbiology Oliver Wendell (American physician) observed mothers who gave birth at home experienced fewer infections than those that gave birth in a hospital Ignaz Semmelweis (Hungarian doctor) showed that women became infected with puerperal fever during delivery by doctors coming directly from the autopsy room

Early Medical Microbiology Joseph Lister (English surgeon) Introduced aseptic techniques Aimed at reducing microbes in a medial setting and preventing wound infections Improved sanitation Promotes use of carbolic acid on bandages and medical instruments

1900s Alexander Fleming Two types of cells recognized!!! observed that a species of Penicillium mold killed bacterial cells led to the development of penicillin Two types of cells recognized!!!

Microbiology—Now Microbiology continues to face many challenges A pathogen can cause more than one disease Pathogens are becoming resistant to antimicrobials Pathogens can be used intentionally to infect large numbers of people through bioterrorism

Science Scientific method 1. Observe some aspect of the natural world and ask questions about it 2. Hypothesis 3. Make predictions 4. Test the predictions 5. Repeat the tests or develop new ones 6. Analyze and report the test results and conclusions

Microscopy Micrometer Size Range Most bacterial and archaeal cells are 1-5 micrometers (µm) in length

How to view microbes? Light Microscopy Visible light passes through multiple lenses and through the specimen Light microscopes usually have at least 3 lenses low-power high-power oil-immersion

How to view microbes? Staining techniques simple stain technique negative stain technique Special stains

Taxonomy Organizing, classifying and naming living things In the mid-1700s, Carolus Linnaeus published Systema Naturae, establishing a uniform system for naming organisms Nomenclature gives scientific names to organisms Identifying and classifying organisms according to specific criteria

Taxonomy Domain Kingdom Phylum Class Order Family Genus species

3 Domains Eubacteria Archaea Eukarya true bacteria peptidoglycan odd bacteria that live in extreme environments high salt, heat, etc. (usually called extremophiles) Eukarya have a nucleus & organelles Protista Algae Fungi Plantae Animalia

Naming “Most” Micoorganisms Binomial (scientific) nomenclature Gives each microbe 2 names: Genus - noun, always capitalized species - adjective, lowercase Both italicized or underlined**** Staphylococcus aureus (S. aureus) Bacillus subtilis (B. subtilis) Escherichia coli (E. coli)

What to expect…….. Different microorganisms How to detect microorganisms Common disease caused by microorganisms How to control the spread of microorganisms Immune system