Chapter 27.5: Prokaryotes have both harmful and beneficial impacts on

humans

Maggie , Will, Namroo

Contents

Intro Pathogenic Prokaryotes Prokaryotes in research and technology

Although one may think the amount of harmful prokaryotes is higher than the amount beneficial prokaryotes, it is actually the opposite.

Prokaryotes cause about half of all human diseases

There are many diseases caused by prokaryotes› Tuberculosis› Diarrheal diseases› Lyme disease (caused by parasites)

Lyme disease

Exotoxins and Endotoxins

Illness producing poisons are classified as exotoxins and endotoxins

Exotoxins are proteins secreted by eukaryotes› Can produce a disease even if the prokaryotes

that manufacture them are not present Endotoxins are lipopolysaccharide

components of the outer membrane of gram-negative bacteria› Only released when the bacteria die and their

cell walls break down

So how have humans slowed the reproduction of prokaryotic diseases?› Antibiotics› Better sanitation habits

Pathogenic Prokaryotes Cont...

Improvements in sanitation and antibiotics has reduced the threat of pathogenic prokaryotes.

However, resistance to the antibiotics are becoming more likely because of the fast reproduction of prokaryotes.

Examples

Horizontal gene transfer turns normally harmless prokaryotes to fatal pathogens.

E.Coli for example is harmless, but strains that cause bloody diarrhea emerged.

O157:H7 causes 75,000 infections per year often from contaminated beef. › It was compared to K-12 and 1,387 out of

5,416 genes have no counterpart in K-12.

Prokaryotes in Research and Technology

Prokaryotes are the principal agents in bioremediation.› Bioremediation is the use of organisms

to remove pollutants from soil, air, or water.

› Bioremediation also breaks down radioactive waste and cleans up oils spills.

Figure 27.17

Technology Cont..

Prokaryotes are used in mining. Through genetic engineering, humans can

now modify prokaryotes to produce vitamins, antibiotics, and hormones.

Craig Venter – one of the leaders of the Human Genome Project.