WELCOME to Microbiology!

(Biology 2240)Instructor: Dr. Dana Nayduch

TEXT: Foundations in Microbiology, 7th edition,

K.P. Talaro

Microbiology

• The study of of organisms too small to be seen without magnification

Evolutionary timeline

Branches of study within microbiology

• Immunology• Public health microbiology &

epidemiology• Food, dairy and aquatic microbiology• Biotechnology• Genetic engineering & recombinant DNA

technology

Microbes are involved in• nutrient production & energy flow

• Decomposition

• production of foods, drugs & vaccines

• Bioremediation

• causing disease (pathogens)

Decomposition and nutrient recycling:Affects content of atmosphere, soil and water

Energy flow and nutrient production: Photosynthesis sunlight + CO2 sugar (energy) + O2

Role of microbes in ENERGY and NUTRIENT flow

Human use of microorganisms

Impact of pathogens

• Pathogens = disease producing organisms• Infectious diseases = caused my microbes• Nearly 2,000 different microbes cause diseases• 10 B infections/year worldwide• 13 M deaths from infections/year worldwide

Top causes of death (US vs. Worldwide)

Worldwide infectious disease statistics

Characteristics of microbes

microorganisms

*Also, helminths

History of Microbiology

Antonie van Leeuwenhoek

• First to observe living microbes

• his single-lens magnified up to 300X

• “Animalcules”

(1632-1723)

Leeuwenhoek’s simple microscope

Robert Hooke

• Contemporary/ collaborator of Leeuwenhoek

• Developed the compound microscope (Ch. 3)

• Wrote “Micrographia” on observations

Scientific Method

• Form a hypothesis - a ___________________ that can be supported or refuted by observation & experimentation predictions

• A lengthy process of experimentation, analysis & testing either supports or refutes the hypothesis.

• Results must be published & repeated by other investigators.

• If ___________ is supported by a growing body of evidence & survives rigorous scrutiny, it moves to the next level of confidence - it becomes a theory

• Evidence of a __________ is so compelling that the next level of confidence is reached - it becomes a ___________ ___________________

Spontaneous generation• Early belief that some forms of life could arise from vital forces present in nonliving or decomposing matter. (flies from manure, etc)

• ___________ vs. ____________

Air/dust source of microbes

Louis Pasteur • Showed microbes caused

fermentation & spoilage• Disproved spontaneous

generation of m.o.• Developed a rabies vaccine.• .

(1822-1895)

Robert Koch• Established a sequence of

experimental steps to show that a specific microbe causes a particular disease. “__________________”

• Developed pure culture methods.

• Identified cause of anthrax, TB, & cholera.

(1843-1910)

• Anthrax; Bacillus anthracis; (Gr., coal)-refers to the "black" blood in killed, diseased animals

• cattle and sheep graze in infected pastures • anthrax spores (resistant form of bacteria) are in soil

enter bloodstream via mucosal abrasions • Animals are very ill, weak, swollen, have black, bloody

discharges• Animal dies and is buried earthworms pick up spores

and carry them to the surface dirt animals graze in infected pastures, etc.

• CONTROL: bury animals at a depth of at least 6 feet (no earthworms this deep)

FIRST DEMONSTRATION OF BACTERIAL DISEASE:1876- Robert Koch

1. The suspected microorganism is present in every case of the disease and absent from healthy animals.

2. One must isolate and grow the microorganism in pure culture.

3. Injection (infection) of a healthy host with the microorganism in pure cultures must cause disease.

4. One must be able to isolate the microorganism from the new host.

Koch’s postulates

Germ theory of disease (really a law ?)

Many diseases are caused by the growth of microbes in the body and not by sins, bad character, or poverty, etc.

High impact on practice of medicine, public health.

Other important contributions to microbiology

• John Tyndall, Ferdinand Cohn – heat-resistant bacterial endospores

• Joseph Lister – Aseptic techniques (in medical setting)– Aseptic techniques employed by

microbiologist prevent contamination of cultures and lab.

Microbial evolution and classification

Evolution- living things change gradually over millions of years

• Changes favoring survival are retained & less beneficial changes are lost.

• All new species originate from preexisting species.• Evolution usually progresses toward greater

complexity.• Closely related organism have similar features

because they evolved from common ancestral forms.

Relatedness = Phylogeny; phylogeny used to create taxonomy

_____________ - system for organizing, classifying & naming living things

Taxa:

• Domain - Archaea, Bacteria & Eukarya• Kingdom – 5 or 6• Phylum (proto, animals) or Division (bacteria,

algae, plants, fungi)• Class • Order• Family• Genus• species

3 domains

• _____________ -true bacteria, peptidoglycan• _____________–odd bacteria that live in

extreme environments, high salt, heat, etc. NOT older than bacteria.

• _____________ have a nucleus, & organelles

Kingdoms (Whittaker system)Which contain microbes?

• __________ (Eubacteria and archaebacteria)• __________(single celled; algae, protozoa)• __________(myceteae) – single or multi-celled • __________– (microscopic larvae; invertebrates such

as helminths, arthropods)• __________• NOTE: no viruses – not “alive”; _____________ .

Sample taxonomy

Naming 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)

Chapter 2

The chemistry of Biology

Fundamental Building Blocks

• ____________ - all materials that occupy space & have mass (mass=amt. of matter)

• Matter is composed of atoms• ____________– simplest form of matter not

divisible into simpler substances without losing its properties– composed of protons, neutrons, & electrons

Models of atoms

____________– atoms that differ in numbers of protons (atomic number)

________________________ = # electrons in outermost shell

Molecules & Bonds

• ____________– distinct chemical substance that results from the combination of two or more atoms (O2, N2)

• ____________– molecule with 2 or more different elements (H2O, CO2, NaCl)

• ____________– when 2 or more atoms share, donate or accept electrons.

• 3 types: covalent, ionic, & hydrogen

3 Types of Chemical Bonds

1. ____________ bonds – electrons are shared among atoms

– polar covalent bonds– unequal sharing– nonpolar covalent bonds– equal sharing

2. ____________ bonds – electrons are transferred to one atom forming positively charged cations & negatively charged anions

3. ____________ bonds – weak bonds between hydrogen & other atoms

3 Types of Chemical Bonds

Covalent bonds

See web Video

Hydrogen bonding, H2O and polar molecules

• Some covalent bonds result in unequal sharing of electrons

• Molecule has “poles” that are relatively negative or positive

• ________________________________________________________________________________

Ionization• Electrons are

____________ (donated/accepted) between atoms

• Valences complement each other, and after the transfer they have full outer shells

• Each atom is now an ion and is charged (+/-)

See web video

H-bonding in H2O

____________– a mixture of one or more substances called solutes, dispersed in a dissolving

medium called a solvent

Solutes – Na+ & Cl-

Solvent – H2O

Concentration = amt. solute/ amt. solvent

• Most biological activities occur in aqueous (water-based) solutions.

• ____________ molecules – dissolve in water (ex. Charged or polar; salts)

• ____________ molecules – repel water (ex. Uncharged or nonpolar; lipids)

• ____________ molecules -have both hydrophilic and hydrophobic properties

pH:• pH scale – ranges from 0 to 14, expresses

the concentration of H+ ions –pH is the negative log of the

concentration (moles/liter) of H+ ions. • pH 6 = moles H+/ l• pH 9 = moles H+/ l0.0000010.000001

0.0000000010.000000001

pH scale

•More H ions = ________________________

•Acids release H+ ions in solution

•Less H ions = ________________________

•Bases release OH- ions in solution

Chemical shorthand

Shows elements involved and #

Shows elements, #, and # of bonds

Shows elements, #, # of bonds and detailed structureCan be abbreviated

Chemical reactions

S + O2 SO2

2H2 + O2 2H2O (must be balanced)

Note: 2H2Subscript denotes a ____________________________________________ ________________________________________

This means ____________________________________________

____________ molecules

• Complex molecules, contain C and H• Make up structures in living things

• ____________– do not contain C and H. example: salt, water

Why Carbon???• Carbon is

VERSATILE• Likes to form

covalent bonds• Can form up to 4

bonds• Gives rise to

interesting structures: Chains, rings, branching molecules

Functional groups of organic compounds

Macromolecules: 4 families of biochemical (organic) molecules

1. ____________2. ____________3. ____________4. ____________ acids

Except for lipids, all are formed by polymerization, where subunits, called monomers are bound into chains called polymers.

____________ synthesis forms polymers; ____________ breaks them.

1. Carbohydrates• Sugars, -ose (pentose = 5; hexose = 6).

“saccharide”• general formula (CH2O)n

• monomer – ____________ (glucose, fructose)• polymer –____________ (starch, cellulose,

glycogen)• subunits linked by glycosidic bonds• functions – structural support, nutrient & energy

1. Carbohydrates

1. Carbohydrates1. Carbohydrates

cellulose starch

Polysaccharides1. Carbohydrates1. Carbohydrates

Polysachharides of microbes

•agar, chitin (fungi, insects; glucosamine)•_______________– glycans with peptide fragments; bacterial cell wall

•________________– LPS – in G- bacteria cell wall

•____________– polysaccharides bound to protein (mucoprotein or glycoprotein)

- Attachment or receptors

1. Carbohydrates1. Carbohydrates

2. Lipids

1. Fats• Not soluble in water (nonpolar; hydrophobic)• Long complex hydrocarbon chains

–triglycerides –phospholipids in membranes

2. Also steroids like cholesterol, waxes

______________

• Glycerol + 3 FA• Stored as fats• High energy storage molecules

2. Lipids2. Lipids

2. Lipids2. Lipids

2. Lipids2. Lipids

Phospholipid:•Found in cell membranes

•Glycerol + 2 FA + phosphate

Cholesterol:Reinforces cell membrane(mycoplasma)

Cell membranes are very important – they separate cells from their environment and regulate interaction with the environment

3. Proteins

• shapers of life• predominant molecules in cells• monomer – ______________– 20• polymer – ___________________________• subunits linked by __________________

(dehydration)• fold into very specific 3-d shapes• function- perform most of the activities in a cell -

enzymes, transport, structure, etc.

20 amino acids

Amino acid basic structure

NH COH

H HO

C

R

3. Proteins3. Proteins

Peptide bonds form by ______________ between amino and carboxyl groups

3. Proteins3. Proteins

Functional groups of AA are involved in protein structure (secondary, tertiary)

They form ________ bonds

3. Proteins3. Proteins

*also covalent bonds with cysteine (disulfide)

3. Proteins3. Proteins

This is an old figure not in your current text book

4. Nucleic acids

• DNA & RNA• Monomer – ______________• DNA – A,T,C,G – Double helix – hereditary

material• RNA – A,U,C,G – organize protein synthesis

Nucleotides• Nitrogenous base (ATGCU) • Sugar (pentose; ribose or deoxyribose)• Phosphate

4. Nucleic Acids4. Nucleic Acids

DNA & RNA 4. Nucleic Acids4. Nucleic Acids

DNA• Is wound in a double helix• The backbone is sugar-

phosphate• The “rungs” of the ladder

are the N bases• The strands are held

together by H-bonds between bases

• ______________________ ______________________

• ______________________ ______________________

DNA replication in cells 4. Nucleic Acids4. Nucleic Acids

RNA

3 kinds• rRNA – makes ribosomes; “protein factories”

(translation)• tRNA – “decodes” DNA code during protein

synthesis• mRNA – carries genetic message from DNA for

translation

4. Nucleic Acids4. Nucleic Acids

ATP – a special nucleotide• Adenosine triphosphate• Energy currency of the cell• Energy carried in bond b/w 2 and 3 phosphate

4. Nucleic Acids4. Nucleic Acids