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COLLEGE PHYSICS

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Chapter 22 PROKARYOTES: BACTERIA AND ARCHAEA

Biology

CAMPBELL

BIOLOGYReece • Urry • Cain • Wasserman • Minorsky • Jackson

EDITION

27Bacteria and

Archaea

Figure 22.1

• Certain prokaryotes can live in extreme environments such as the Morning Glory pool, a hot spring in Yellowstone National Park. The spring’s vivid blue color is from the prokaryotes that thrive in its very hot waters. (credit: modification of work by Jon Sullivan)

Fig. 27-1

Anton van Leeuwenhoek

• Animalcules

Pasteur

• Asepetic technique –

heat treatment

• Fermentation

• Pasteurization

Germ Theory of Disease

• Semmelweis childbirth fever

• Lister aseptic technique for medicine

• Robert Koch anthrax• “pure” cultures

Koch’s Postulates

• cause-and-effect relationship

between a bacteria (or any other

type of microorganism) and a

clinical disease

• 4 criteria

• Bacteria present in all animals &

isolated from

• Isolated bacteria grown in pure

culture

• Pure culture bacteria inoculated into

healthy host to reproduce

• Re-isolate the bacteria

• Limitations:

• Can’t be grown (leprosy & syphilis)

• No suitable model host

• Multiple causes

• Minor or chronic conditions

Prokaryotes

• DNA not membrane

• Lack membrane bound

organelles

• No histone proteins

• Peptidoglycan

• Widespread

• Size (0.5 – 5 µm)

• Bacteria or Archaea

Figure 22.9

• Three basic categories based on their shape:(a) cocci, or spherical (a pair is shown); (b)bacilli, or rod-shaped; and (c) spirilli, or spiral-shaped. (credit a: modification of work by Janice Haney Carr, Dr. Richard Facklam, CDC; credit c: modification of work by Dr. David Cox; scale-bar data from Matt Russell)

• Strepto: chain

• Staphylo: cluster

Fig. 27-3

Cellwall

Peptidoglycanlayer

Plasma membrane

Protein

Gram-positive

bacteria

(a) Gram-positive: peptidoglycan trapscrystal violet.

Gram-negativebacteria

(b) Gram-negative: crystal violet is easily rinsed away,revealing red dye.

20 µm

Cellwall

Plasma membrane

Protein

Carbohydrate portionof lipopolysaccharide

Outermembrane

Peptidoglycanlayer

Cell Surface StructuresHans Christian Gram Gram Staining

LPS component•O polysacch antigens for ID (E. coli O157:H7)

•Lipid A endotoxin toxic (fever/shock)

antibiotics

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• Bacteria are divided into two major groups: Gram positive and Gram negative. Both groups have a cell wall composed of

peptidoglycan: in Gram-positive bacteria, the wall is thick, whereas in Gram-negative bacteria, the wall is thin. In Gram-

negative bacteria, the cell wall is surrounded by an outer membrane that contains lipopolysaccharides and lipoproteins.

Porins are proteins in this cell membrane that allow substances to enter the outer membrane of Gram-negative bacteria.

In Gram-positive bacteria, lipoteichoic acid anchors the cell wall to the cell membrane. (credit: modification of work by

“Franciscosp2”/Wikimedia Commons)

Figure 22.16

Fig. 27-3c

Gram-positive

bacteria

Gram-negativebacteria

20 µm

AntibioticsAntibiotics target peptidoglycan layer

• Broad spectrum Gram + & - (ampicilin/tetracycline)

• Narrow spectrum specific families

• Both dose, duration & state of invading bacteria

Antibiotics

• Bacteriostatic inhibits or delay growth & repro

• Bactericidal kills bacteria

• This scanning electron micrograph shows Clostridium difficile, a Gram-positive, rod-shaped bacterium that causes severe diarrhea. Infection commonly occurs after the normal gut fauna is eradicated by antibiotics. (credit: modification of work by CDC, HHS; scale-bar data from Matt Russell)

Figure 22.30

Fig. 27-4

Capsule

200 nm

Glycocalyx capsule (attachment, prevents, dehydration, provides virulence)

Bacterialcell wall

Fig. 16-2

Living S cells

(control)

Living R cells

(control)Heat-killed

S cells (control)

Mixture of heat-killed S cells and living R cells

Mouse diesMouse dies Mouse healthy Mouse healthy

Living S cells

RESULTS

EXPERIMENT

F. Griffith

1920’s

Transformation

Fig. 27-9

Endospore

0.3 µm

Resting cells Metabolically inactive

survives extreme heat, lack of water,

exposure to many toxic chemicals & radiation

Bacillus & Clostridium

Fig. 27-5

Fimbriae

200 nm

Figure 27.7

20 nmFilament

MotorCell wall

Plasmamembrane Rod

Peptidoglycanlayer

Flagellum

Chemotaxis (+/-)

Phototaxis (+/-)

Fig. 27-7

(a) Aerobic prokaryote (b) Photosynthetic prokaryote

Thylakoidmembranes

Respiratorymembrane

0.2 µm 1 µm

No complex compartments

Infolding of cell membrane specialized metabolic functions

Internal Organization and DNA

Figure 27.9

Plasmids

Chromosome

Internal Organization and DNA

DNA replication, transcription, and translation

differences from eukaryotes?

Binary FissionQuick reproduction – why?

• Small

• Short generation time

• Binary fission

Genetically Diverse (highly variable)

3) Genetic recombination

Horizontal Gene Transfer• Transformation

• Transduction

• Conjugation

1) Rapid reproduction

2) Mutation

Fig. 16-2

Living S cells

(control)

Living R cells

(control)Heat-killed

S cells (control)

Mixture of heat-killed S cells and living R cells

Mouse diesMouse dies Mouse healthy Mouse healthy

Living S cells

RESULTS

EXPERIMENTTransformation

F. Griffith

1920’s

Transformation

Phage infects bacterialdonor cell with A+ and B+

alleles.

Phage DNA is replicatedand proteins synthesized.

Fragment of DNA with A+

allele is packaged withina phage capsid.

Phage with A+ alleleinfects bacterial recipientcell.

Incorporation of phageDNA creates recombinantcell with genotype A+ B−.

Donor cell

Phage DNA

B−A−

Crossingover

Recombinantcell

Recipient cell

B−A+

Transduction

Fig. 27-12

Sex pilus 1 µm

Conjugation F factor

Fig. 27-13

F plasmid

F+ cell

F– cell

Matingbridge

Bacterial chromosome

Bacterialchromosome

(a) Conjugation and transfer of an F plasmid

F+ cell

F– cell

(b) Conjugation and transfer of part of an Hfr bacterial chromosome

F factor

Hfr cell A+A+

A+A– A– A–

A– A+

Recombinant

F– bacterium

F Factor & PlasmidsR Factor & Antibiotic resistance

Crossing over

Enzymesdegrade andDNA notincorporated

Conjugation F factor

• Besides binary fission, there are three other mechanisms by which prokaryotes can exchange DNA. In (a)

transformation, the cell takes up prokaryotic DNA directly from the environment. The DNA may remain

separate as plasmid DNA or be incorporated into the host genome. In (b) transduction, a bacteriophage injects

DNA into the cell that contains a small fragment of DNA from a different prokaryote. In (c) conjugation, DNA

is transferred from one cell to another via a pilus that connects the two cells.

Figure 22.17

Horizontal Gene Transfer

Table 27-1

• Autotrophs require CO2 as a carbon source

• Heterotrophs require an organic nutrient to make organic compounds

Oxygen Preferences

• Obligate aerobes

• Obligate anaerobes• Clostridium tetani

• C. botulinum

• C. perfringens

• Facultative anaerobes• Staphylococcus

• E. coli

• Prokaryotes play a significant role in continuously moving carbon through the biosphere. (credit: modification of work by John M. Evans and Howard Perlman, USGS)

Figure 22.18

Carbon Cycle

• Prokaryotes play a key role in the nitrogen cycle. (credit: Environmental Protection Agency)

Figure 22.19

Nitrogen Cycle

• Soybean (Glycine max) is a legume that interacts symbiotically with the soil bacterium Bradyrhizobium japonicum to form specialized structures on the roots called nodules where nitrogen fixation occurs. (credit: USDA

Figure 22.27

Nitrogen fixation

Fig. 27-14

Photosyntheticcells

Heterocyte

20 µm

Nitrogen fixation

Fig. 27-15

Metabolic cooperation Biofilms – Streptococcus mutans

• Five stages of biofilm development are shown. During stage 1, initial attachment, bacteria adhere to a solidsurface via weak van der Waals interactions. During stage 2, irreversible attachment, hairlike appendages called pili permanently anchor the bacteria to the surface. During stage 3, maturation I, the biofilm grows through cell division and recruitment of other bacteria. An extracellular matrix composed primarily of polysaccharides holds the biofilm together. During stage 4, maturation II, the biofilm continues to grow and takes on a more complex shape. During stage 5, dispersal, the biofilm matrix is partly broken down, allowing some bacteria to escape and colonize another surface. Micrographs of a Pseudomonas aeruginosa biofilm in each of the stages of development are shown. (credit: D. Davis, Don Monroe, PLoS)

Figure 22.8

Metabolic cooperation Biofilms – ex.Streptococcus mutans

Figure 22.11

• Bacteria and Archaea are both prokaryotes but differ enough to be placed in separate domains. An ancestor of modern Archaea is believed to have given rise to Eukarya, the third domain of life. Archaeal and bacterial phyla are shown; the evolutionary relationship between these phyla is still open to debate.

Figure 27.15

UNIVERSALANCESTOR

Eukaryotes

Korarchaeotes

Euryarchaeotes

Crenarchaeotes

Nanoarchaeotes

Proteobacteria

Chlamydias

Spirochetes

Cyanobacteria

Gram-positivebacteria

Table 27-2

Fig. 27-17

Archaea

Figure 22.6

(a) The Dead Sea is hypersaline. Nevertheless, salt-tolerant bacteria thrive in this sea.

(b) These halobacteria cells can form salt-tolerant bacterial mats. (credit a: Julien Menichini; credit b: NASA; scale-bar data from Matt Russell)

Fig. 27-20

Symbiosis mutualism, commensalism & parasite

Fig. 27-21

Pathogenic bacteria

Figure 22.21

• The (a) Great Plague of London killed an estimated 200,000 people, or about twenty percent of the city’s population.The causative agent, the (b) bacterium Yersinia pestis, is a Gram-negative, rod-shaped bacterium from the class GammaProteobacteria. The disease is transmitted through the bite of an infected flea, which is infected by a rodent. Symptomsinclude swollen lymph nodes, fever, seizure, vomiting of blood, and (c) gangrene. (credit b: Rocky MountainLaboratories, NIAID, NIH; scale-bar data from Matt Russell; credit c: Textbook of Military Medicine, Washington, D.C.,U.S. Dept. of the Army, Office of the Surgeon General, Borden Institute)

Figure 22.22

• The map shows regions where bacterial diseases are emerging or reemerging. (credit: modification of work by NIH)

Pathogenic Bacteria

• Exotoxin• Gram (+)

• Part of growth & metabolism

• Proteins (enzymes) secreted

• Gene location plasmids

• Antitoxins provide immunity

• Types:

» Cytotoxic (diptheria, gangrene)

» Neurotoxins (botulism,tetanus)

» Enterotoxins (cholera, staph)

• Endotoxins• Gram (-)

• Outer portion of cell wall

• LPS

• When Gram (-) dies

• Activates blood clotting

proteins

• Fever & shock

• Bioterrorism (anthrax)

Fig. 27-22

Bioremediation & Technology

(a) Cleaning up oil after the Valdez spill in Alaska, workers hosed oil from beaches and then used a floating boom to corral the oil, which was finally skimmed from the water surface. Some species of bacteria are able to solubilize and degrade the oil.

(b) One of the most catastrophic consequences of oil spills is the damage to fauna. (credit a: modification of work by NOAA; credit b: modification of work by GOLUBENKOV, NGO: Saving Taman)

Figure 22.29

• Some of the products derived from the use of prokaryotes in early biotechnology include (a)cheese, (b) wine, (c) beer and bread, and (d) yogurt. (credit bread: modification of work by F. Rodrigo/Wikimedia Commons; credit wine: modification of work by Jon Sullivan; credit beer and bread: modification of work by Kris Miller; credit yogurt: modification of work by Jon Sullivan)

Figure 22.28

Products derived from prokaryotes

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