Ch 01_lecture_presentation

PowerPoint® Lecture Presentations prepared byBradley W. Christian, McLennan Community College

C H A P T E R

© 2016 Pearson Education, Inc.

The Microbial World and You

1


Microbes in Our Lives

Learning Objective1-1 List several ways in which microbes affect our

lives.



• Microorganisms are organisms that are too small to be seen with the unaided eye

• Microbes include bacteria, fungi, protozoa, microscopic algae, and viruses



• A few are pathogenic (disease-producing) • Decompose organic waste• Generate oxygen by photosynthesis• Produce chemical products such as ethanol,

acetone, and vitamins• Produce fermented foods such as vinegar, cheese,

and bread• Produce products used in manufacturing

(e.g., cellulase) and disease treatment (e.g., insulin)


Designer Jeans: Made by Microbes?

• Denim fading: Trichoderma• Cotton production: Gluconacetobacter• Bleaching: mushroom peroxidase• Indigo: Escherichia coli• Plastic: bacterial polyhydroxyalkanoate


Applications of Microbiology 1.1


Applications of Microbiology 1.2



• Knowledge of microorganisms allows humans to• Prevent food spoilage• Prevent disease • Understand causes and transmission of disease to

prevent epidemics


Check Your Understanding Describe some of the destructive and beneficial

actions of microbes.1-1


Naming and Classifying Microorganisms

Learning Objectives1-2 Recognize the system of scientific

nomenclature that uses two names: a genus and a specific epithet.

1-3 Differentiate the major characteristics of each group of microorganisms.

1-4 List the three domains.


Naming and Classifying Microorganisms

• Carolus Linnaeus established the system of scientific nomenclature in 1735

• Each organism has two names: the genus and the

specific epithet


Nomenclature

• Scientific names• Are italicized or underlined

• The genus is capitalized; the specific epithet is lowercase• Are "Latinized" and used worldwide• May be descriptive or honor a scientist


Nomenclature

• Escherichia coli • Honors the discoverer, Theodor Escherich• Describes the bacterium's habitat—the large intestine,

or colon


Nomenclature

• Staphylococcus aureus • Describes the clustered (staphylo-) spherical

(coccus) cells• Describes the gold-colored (aureus) colonies


Nomenclature

• After the first use, scientific names may be abbreviated with the first letter of the genus and the specific epithet:• Escherichia coli and Staphylococcus aureus are found

in the human body• E. coli is found in the large intestine, and S. aureus is on

skin


Check Your Understanding Distinguish a genus from a specific epithet.

1-2


Types of Microorganisms

• Bacteria• Archaea• Fungi• Protozoa• Algae• Viruses• Multicellular Animal Parasites


Figure 1.1 Types of microorganisms.

BacteriaFoodparticle

Sporangia

Pseudopod

HIVsCD4 + T cell


Bacteria

• Prokaryotes• ”Prenucleus"

• Single-celled• Peptidoglycan cell walls• Divide via binary fission• Derive nutrition from organic or inorganic

chemicals or photosynthesis


Figure 1.1a Types of microorganisms.

Bacteria


Archaea

• Prokaryotes• Lack peptidoglycan cell walls• Often live in extreme environments• Include:• Methanogens• Extreme halophiles• Extreme thermophiles


Fungi

• Eukaryotes• Distinct nucleus

• Chitin cell walls• Absorb organic chemicals for energy• Yeasts are unicellular• Molds and mushrooms are multicellular • Molds consist of masses of mycelia, which are

composed of filaments called hyphae


Figure 1.1b Types of microorganisms.

Sporangia


Protozoa

• Eukaryotes• Absorb or ingest organic chemicals• May be motile via pseudopods, cilia, or flagella• Free-living or parasitic (derive nutrients from a

living host)


Figure 1.1c Types of microorganisms.

Pseudopod

Foodparticle


Algae

• Eukaryotes• Cellulose cell walls• Found in freshwater, saltwater, and soil• Use photosynthesis for energy• Produce oxygen and carbohydrates


Figure 1.1d Types of microorganisms.


Viruses

• Acellular• Consist of DNA or RNA core• Core is surrounded by a protein coat• Coat may be enclosed in a lipid envelope• Are replicated only when they are in a living

host cell• Inert outside living hosts


Figure 1.1e Types of microorganisms.

CD4 + T cell HIVs


Multicellular Animal Parasites

• Eukaryotes• Multicellular animals• Not strictly microorganisms• Parasitic flatworms and roundworms are called

helminths• Some microscopic stages in their life cycles


Check Your Understanding Which groups of microbes are prokaryotes?

Which are eukaryotes?1-3


Classification of Microorganisms

• Developed by Carl Woese• Three domains based on cellular organization• Bacteria• Archaea• Eukarya

• Protists• Fungi• Plants• Animals


Figure 10.1 Three-Domain System.


Check Your Understanding What are the three domains?

1-4


A Brief History of Microbiology

Learning Objectives1-5 Explain the importance of observations made

by Hooke and van Leeuwenhoek.1-6 Compare spontaneous generation and

biogenesis.1-7 Identify the contributions to microbiology made

by Needham, Spallanzani, Virchow, and Pasteur.


The First Observations

• 1665: Robert Hooke reported that living things are composed of little boxes, or "cells"• Marked the beginning of cell theory: All living things are

composed of cells• The first microbes were observed from 1623–1673

by Anton van Leeuwenhoek• "Animalcules" viewed through magnifying lenses


Figure 1.2b Anton van Leeuwenhoek's microscopic observations.

Lens

Location of specimen on pin

Specimen-positioning screw

Focusing control

Stage-positioning screw

Microscope replica


Check Your Understanding What is the cell theory?

1-5


The Debate over Spontaneous Generation

• Spontaneous generation: the hypothesis that life arises from nonliving matter; a "vital force" is necessary for life

• Biogenesis: the hypothesis that living cells arise only from preexisting living cells



• 1668: Francesco Redi filled jars with decaying meat

Conditions Results

Jars covered with fine net No maggots

Open jars Maggots appeared

Sealed jars No maggots

From where did the maggots come?What was the purpose of the sealed jars?Spontaneous generation or biogenesis?


Conditions Results

Nutrient broth heated, then placed in covered flask

Microbial growth

From where did the microbes come?Spontaneous generation or biogenesis?


• 1745: John Needham put boiled nutrient broth into covered flasks


Conditions Results

Nutrient broth placed in flask, sealed, then heated

No microbial growth

Spontaneous generation or biogenesis?


• 1765: Lazzaro Spallanzani boiled nutrient solutions in sealed flasks


The Theory of Biogenesis

• 1858: Rudolf Virchow said cells arise from preexisting cells



• 1861: Louis Pasteur demonstrated that microorganisms are present in the air

Conditions Results

Nutrient broth placed in flask, heated, NOT sealed

Microbial growth

Nutrient broth placed in flask, heated, then immediately sealed

No microbial growth

Spontaneous generation or biogenesis?



• Pasteur also used S-shaped flasks • Keep microbes out but let air in

• Broth in flasks showed no signs of life• Neck of flask traps microbes• Microorganisms originate in air or fluids, not

mystical forces


Figure 1.3 Disproving the Theory of Spontaneous Generation.


Check Your Understanding What evidence supported spontaneous

generation?1-6

How was spontaneous generation disproved?1-7


A Brief History of Microbiology

Learning Objectives1-8 Explain how Pasteur's work influenced Lister

and Koch.1-9 Identify the importance of Koch's postulates.1-10 Identify the importance of Jenner's work.1-11 Identify the contributions to microbiology made

by Ehrlich and Fleming.


The Golden Age of Microbiology

• 1857–1914• Beginning with Pasteur's work, discoveries

included the relationship between microbes and disease, immunity, and antimicrobial drugs



• Pasteur showed that microbes are responsible for fermentation

• Fermentation is the microbial conversion of sugar to alcohol in the absence of air

• Microbial growth is also responsible for spoilage of food and beverages

• Bacteria that use air spoil wine by turning it to vinegar (acetic acid)



• Pasteur demonstrated that these spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine

• Pasteurization is the application of a high heat for a short time to kill harmful bacteria in beverages


Figure 1.4 Milestones in the Golden Age of Microbiology (1 of 3).


The Germ Theory of Disease

• 1835: Agostino Bassi showed that a silkworm disease was caused by a fungus

• 1865: Pasteur showed that another silkworm disease was caused by a protozoan

• 1840s: Ignaz Semmelweis advocated handwashing to prevent transmission of puerperal fever from one obstetrical patient to another



• 1860s: Applying Pasteur's work showing that microbes are in the air, can spoil food, and cause animal diseases, Joseph Lister used a chemical antiseptic (phenol) to prevent surgical wound infections



• 1876: Robert Koch discovered that a bacterium causes anthrax and provided the experimental steps, Koch's postulates, to demonstrate that a specific microbe causes a specific disease


Vaccination

• 1796: Edward Jenner inoculated a person with cowpox virus, who was then immune from smallpox

• Vaccination is derived from the Latin word vacca, meaning cow

• The protection is called immunity


Check Your Understanding Summarize in your own words the germ theory of

disease.1-8

What is the importance of Koch's postulates?1-9

What is the significance of Jenner's discovery? 1-10


The Birth of Modern Chemotherapy: Dreams of a "Magic Bullet"• Treatment of disease with chemicals is called

chemotherapy• Chemotherapeutic agents used to treat infectious

disease can be synthetic drugs or antibiotics• Antibiotics are chemicals produced by bacteria

and fungi that inhibit or kill other microbes


The First Synthetic Drugs

• Quinine from tree bark was long used to treat malaria

• Paul Ehrlich speculated about a "magic bullet" that could destroy a pathogen without harming the host• 1910: Ehrlich developed a synthetic arsenic drug,

salvarsan, to treat syphilis• 1930s: Sulfonamides were synthesized


A Fortunate Accident—Antibiotics

• 1928: Alexander Fleming discovered the first antibiotic (by accident)

• Fleming observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus

• 1940s: Penicillin was tested clinically and mass-produced


Normalbacterialcolony

Area ofinhibitedbacterialgrowth

Penicilliumcolony

Figure 1.5 The discovery of penicillin.


Check Your Understanding What was Ehrlich's "magic bullet"?

1-11


Modern Developments in Microbiology

Learning Objectives1-12 Define bacteriology, mycology, parasitology,

immunology, and virology.1-13 Explain the importance of microbial genetics

and molecular biology.


Bacteriology, Mycology, and Parasitology

• Bacteriology is the study of bacteria• Mycology is the study of fungi• Parasitology is the study of protozoa and

parasitic worms


Figure 1.6 Parasitology: the study of protozoa and parasitic worms.


Immunology

• Immunology is the study of immunity• Vaccines and interferons are used to prevent and cure

viral diseases• A major advance in immunology occurred in 1933

when Rebecca Lancefield classified streptococci based on their cell wall components


Figure 1.7 Rebecca Lancefield (1895–1981), who discovered differences in the chemical composition of a polysaccharide in the cell walls of many pathogenic streptococci.


Virology

• Virology is the study of viruses• Dmitri Iwanowski in 1892 and Wendell Stanley in

1935 discovered the cause of mosaic disease of tobacco as a virus

• Electron microscopes have made it possible to study the structure of viruses in detail


Recombinant DNA Technology

• Microbial genetics: the study of how microbes inherit traits

• Molecular biology: the study of how DNA directs protein synthesis

• Genomics: the study of an organism's genes; has provided new tools for classifying microorganisms

• Recombinant DNA: DNA made from two different sources• In the 1960s, Paul Berg inserted animal DNA into

bacterial DNA, and the bacteria produced an animal protein


Recombinant DNA Technology

• 1941: George Beadle and Edward Tatum showed that genes encode a cell's enzymes

• 1944: Oswald Avery, Colin MacLeod, and Maclyn McCarty showed that DNA is the hereditary material

• 1953: James Watson and Francis Crick proposed a model of DNA structure

• 1961: François Jacob and Jacques Monod discovered the role of mRNA in protein synthesis


Figure 1.4 Milestones in the Golden Age of Microbiology.


Check Your Understanding Define bacteriology, mycology, parasitology,

immunology, and virology. 1-12

Differentiate microbial genetics from molecular biology. 1-13


Microbes and Human Welfare

Learning Objectives1-14 List at least four beneficial activities of

microorganisms.1-15 Name two examples of biotechnology that use

recombinant DNA technology and two examples that do not.


Recycling Vital Elements

• Microbial ecology is the study of the relationship between microorganisms and their environment

• Bacteria convert carbon, oxygen, nitrogen, sulfur, and phosphorus into forms used by plants and animals


Bioremediation: Using Microbes to Clean Up Pollutants• Bacteria degrade organic matter in sewage• Bacteria degrade or detoxify pollutants such as oil

and mercury


Figure 27.8 Composting municipal wastes.


Insect Pest Control by Microorganisms

• Microbes that are pathogenic to insects are alternatives to chemical pesticides• Prevent insect damage to agricultural crops and disease

transmission• Bacillus thuringiensis infections are fatal in many

insects but harmless to animals and plants


Figure 11.21 Bacillus.

Bacillus thuringiensis. The diamond-shapedcrystals shown next to the endospore are toxicto insects that ingest them. This electronmicrograph was made using the technique ofshadow casting.

Endospore

Collapsed B. thuringiensis

Toxic crystal


Modern Biotechnology and Recombinant DNA Technology

• Biotechnology is the use of microbes for practical applications, such as producing foods and chemicals

• Recombinant DNA technology enables bacteria and fungi to produce a variety of proteins, vaccines, and enzymes• Missing or defective genes in human cells can be

replaced in gene therapy• Genetically modified bacteria are used to protect crops

from insects and from freezing


Check Your Understanding Name two beneficial uses of bacteria.

1-14 Differentiate biotechnology from recombinant DNA

technology. 1-15


Microbes and Human Disease

Learning Objectives1-16 Define normal microbiota and resistance.1-17 Define biofilm.1-18 Define emerging infectious disease.


Normal Microbiota

• Bacteria were once classified as plants, giving rise to the term flora for microbes• This term has been replaced by microbiota

• Microbes normally present in and on the human body are called normal microbiota


Figure 1.8 Several types of bacteria found as part of the normal microbiota on the surface of the human tongue.


Normal Microbiota

• Normal microbiota prevent growth of pathogens• Normal microbiota produce growth factors such as

vitamins B and K• Resistance is the ability of the body to ward off

disease• Resistance factors include skin, stomach acid, and

antimicrobial chemicals


Biofilms

• Microbes attach to solid surfaces and grow into masses

• They will grow on rocks, pipes, teeth, and medical implants

• Biofilms can cause infections and are often resistant to antibiotics


Figure 1.9 Biofilm on a catheter.

Staphylococcus


Emerging Infectious Diseases

• When a pathogen invades a host and overcomes the host's resistance, disease results

• Emerging infectious diseases (EIDs): new diseases and diseases increasing in incidence



• Middle East respiratory syndrome (MERS)• Caused by Middle East respiratory syndrome

coronavirus (MERS-CoV)• Common to SARS

• Severe acute respiratory syndrome• 100 deaths in the Middle East from 2012 to 2014



• Avian influenza A (H5N1)• Influenza A virus• Primarily in waterfowl and poultry• Sustained human-to-human transmission has not yet

occurred


Figure 13.3b Morphology of an enveloped helical virus.

Spikes



• Methicillin-resistant Staphylococcus aureus (MRSA)• 1950s: Penicillin resistance developed• 1980s: Methicillin resistance• 1990s: MRSA resistance to vancomycin reported

• VISA: vancomycin-intermediate S. aureus • VRSA: vancomycin-resistant S. aureus



• West Nile encephalitis (WNE)• Caused by West Nile virus• First diagnosed in the West Nile region of Uganda

in 1937• Appeared in New York City in 1999• In nonmigratory birds in 48 states• Transmitted between birds and to horses and humans

by mosquitoes


Diseases in Focus 22.2 (1 of 3)



• Bovine spongiform encephalopathy • Caused by a prion

• An infectious protein that also causes Creutzfeldt-Jakob disease (CJD)

• New variant of CJD in humans is related to cattle that have been given feed made from prion-infected sheep


Figure 22.18b Spongiform encephalopathies.

Holes



• E. coli O157:H7 • Toxin-producing strain of E. coli• First seen in 1982; causes bloody diarrhea• Leading cause of diarrhea worldwide


Figure 25.11 Pedestal formation by Enterohemorrhagic E. coli (EHEC) O157:H7.



• Ebola hemorrhagic fever (EHF)• Ebola virus• Causes fever, hemorrhaging, and blood clotting• Transmitted via contact with infected blood or body fluids• First identified near Ebola River, Congo• 2014 outbreak in Guinea; hundreds killed


Figure 23.21 Ebola hemorrhagic virus.



• Cryptosporidiosis• Cryptosporidium protozoa• First reported in 1976• Causes 30% of diarrheal illness in developing countries• In the United States, transmitted via water


Figure 25.17 Cryptosporidiosis.

OocystIntestinalmucosa



• AIDS (acquired immunodeficiency syndrome)• Caused by human immunodeficiency virus (HIV)• First identified in 1981• Sexually transmitted infection affecting males and

females• Worldwide epidemic infecting 35 million people;

6000 new infections every day• HIV/AIDS in the United States: 26% are female, and

49% are African American


Check Your Understanding Differentiate normal microbiota and infectious

disease. 1-16

Why are biofilms important? 1-17

What factors contribute to the emergence of an infectious disease? 1-18

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