CH 27 Origin of Life & Bacteria

Universe formed 15 billion years ago (Big Bang) Galaxies formed from stars, dust and gas Earth formed 4.6 billion years ago

Suns energy stripped away 1 st atmosphere 2 nd atmosphere formed from volcanic outgassing Primitive atmosphere: CO 2, water vapor, lesser amts of CO, N 2, H 2, HCl, and traces of NH 3 and CH 4 (3.5 bya)

O 2 came in 1.5 bya Autotrophic Organisms: photosynthesis Another environmental change Result in evolution

0.5 billion years ago Atmosphere O 2 to 1% current Compare to present: 78% N 2, 21% O 2, 0.04% CO 2, + trace gasses Relatively small, most single cell Start of multicellularity Increase in cell complexity

Life began~ 3.5 bya Organic molecules (C H O N P S) swimming in shallow seas Stage 1: Abiotic synthesis of organic molecules such as proteins, amino acids and nucleotides

Stage 2: joining of small molecules (monomers) into large molecules

Stage 3: origin of self-replicating molecules that eventually made inheritance possible

Stage 4: packaging these molecules into pre-cells, droplets of molecules with membranes that maintained an internal chemistry

Thomas Huxley- Search for origin of life Wyville Thompson: HMS Challenger ( ) found it was actually diatomacous ooze reacting with seawater and ethyl alcohol Bathybias heckali- primordial ooze

Miller and Urey’s Experiment ELECTRICITY!!! Organic molecules like amino acids

Produced: 20 amino acids Several sugars Lipids Purine and pyrimidine bases (found in DNA, RNA & ATP)

Concept 27.4: Molecular systematics is illuminating prokaryotic phylogeny Until the late 20th century, systematists based prokaryotic taxonomy on phenotypic criteria Applying molecular systematics to the investigation of prokaryotic phylogeny has produced dramatic results

Lessons from Molecular Systematics Molecular systematics led to the splitting of prokaryotes into bacteria and archaea Molecular systematists continue to work on the phylogeny of prokaryotes © 2011 Pearson Education, Inc.

Eukaryotes Korarchaeotes Euryarchaeotes Crenarchaeotes Nanoarchaeotes Proteobacteria Chlamydias Spirochetes Cyanobacteria Gram-positive bacteria Domain Bacteria Domain Archaea Domain Eukarya UNIVERSAL ANCESTOR Figure 27.15

The use of polymerase chain reaction (PCR) has allowed for more rapid sequencing of prokaryote genomes A handful of soil may contain 10,000 prokaryotic species Horizontal gene transfer between prokaryotes obscures the root of the tree of life © 2011 Pearson Education, Inc.

Figure 27.UN02 Eukarya Archaea Bacteria

Table 27.2

Archaea Archaea share certain traits with bacteria and other traits with eukaryotes © 2011 Pearson Education, Inc.

Archaebacteria Archaebacteria are CHEMICALLY DISTINCT from other BACTERIA in several ways: 1.The Cell Walls, Cell Membranes, and Ribosomal RNA are different from those of other BACTERIA. No PEPTIDOGLYCAN. 2.Extremophiles 3.The PREFIX "ARCHEA" means ANCIENT. 4.Archaebacteria live in conditions similar to when life first appeared and began to evolve.

Methanogens Archaebacteria Types Extreme Halophiles Thermoacidophiles Hot springs sewage Great salt lakes

Archaebacteria Purple sulfur bacteria

Chemosynthesis 6CO 2 +6H 2 O+3H 2 S  C 6 H 12 O 6 +3H 2 SO 4

Kingdom Monera Species number low (~17, 000), but most numerous on Earth 3.5 byo Two Divisions Eubacteria (Bacteria & Cyanobacteria) Archaebacteria

l Prokaryotic l Single-celled l Diverse energy types: Chemoautotrophic- Purple sulfur bacteria Photoautotrophic- cyanobacteria Heterotrophic- E. coli l saprobes l parasites Kingdom Monera

l Some with cell walls, but cell walls composed of peptidoglycan, not cellulose (as in higher plants). l Asexual and sexual reproduction Kingdom Monera

anthrax pneumonia cyanobacteria Eubacteria

BASIC SHAPES OF EUBACTERIA SPHERICAL ROD-SHAPED SPIRILLA

Gram-Positive Bacteria Gram-positive bacteria include – Actinomycetes, which decompose soil – Bacillus anthracis, the cause of anthrax – Clostridium botulinum, the cause of botulism – Some Staphylococcus and Streptococcus, which can be pathogenic – Mycoplasms, the smallest known cells © 2011 Pearson Education, Inc.

Most Species of Eubacteria may be Grouped Based on Staining Gram-Negative –thin layer of peptidoglycan –Stain pink –Endotoxins Gram-Positive –Thicker layer of peptidogycan –Stain purple –Exotoxins (released when bacteria die)

Gram + Gram -

Gram-Positive Bacteria Streptomyces, the source of many antibiotics (SEM)

Gram-Positive Bacteria Hundreds of mycoplasmas covering a human fibroblast cell (colorized SEM)

Proteobacteria These gram-negative bacteria include photoautotrophs, chemoautotrophs, and heterotrophs Some are anaerobic, and others aerobic

Figure a Alpha Beta Gamma Delta Proteo- bacteria Epsilon Subgroup: Alpha Proteobacteria Rhizobium (arrows) inside a root cell of a legume (TEM) 2.5  m Subgroup: Delta Proteobacteria Subgroup: Gamma Proteobacteria Subgroup: Epsilon Proteobacteria Nitrosomonas (colorized TEM) 1  m Subgroup: Beta Proteobacteria 2  m 300  m Helicobacter pylori (colorized TEM) Fruiting bodies of Chondromyces crocatus, a myxobacterium (SEM) 200  m Thiomargarita namibiensis containing sulfur wastes (LM)

Figure 27.17a Alpha Beta Gamma Delta Proteobacteria Epsilon

Subgroup: Alpha Proteobacteria Many species are closely associated with eukaryotic hosts Scientists hypothesize that mitochondria evolved from aerobic alpha proteobacteria through endosymbiosis

Example: Rhizobium, which forms root nodules in legumes and fixes atmospheric N 2 Example: Agrobacterium, which produces tumors in plants and is used in genetic engineering

Figure 27.17b Subgroup: Alpha Proteobacteria Rhizobium (arrows) inside a root cell of a legume (TEM) 2.5  m

Subgroup: Beta Proteobacteria Example: the soil bacterium Nitrosomonas, which converts NH 4 + to NO 2 –

Figure 27.17c Nitrosomonas (colorized TEM) 1  m Subgroup: Beta Proteobacteria

Subgroup: Gamma Proteobacteria Examples include sulfur bacteria such as Chromatium and pathogens such as Legionella, Salmonella, and Vibrio cholerae Escherichia coli resides in the intestines of many mammals and is not normally pathogenic

Figure 27.17d Subgroup: Gamma Proteobacteria 200  m Thiomargarita namibiensis containing sulfur wastes (LM)

Subgroup: Delta Proteobacteria Example: the slime-secreting myxobacteria

Figure 27.17e Subgroup: Delta Proteobacteria 300  m Fruiting bodies of Chondromyces crocatus, a myxobacterium (SEM)

Subgroup: Epsilon Proteobacteria This group contains many pathogens including Campylobacter, which causes blood poisoning, and Helicobacter pylori, which causes stomach ulcers

Gastric ulcers erosion of stomach wall; pain occurs 1-3 hrs after eating 90% of recurrent ulcers due to bacterial infection, which destroys mucous protective barrier; Treatment- use antibiotic therapy to kill bacteria Helicobacter pylori Barry Marshal

Chlamydias These bacteria are parasites that live within animal cells Chlamydia trachomatis causes blindness and nongonococcal urethritis by sexual transmission

Figure 27.17g Chlamydias 2.5  m Chlamydia (arrows) inside an animal cell (colorized TEM)

Spirochetes These bacteria are helical heterotrophs Some are parasites, including Treponema pallidum, which causes syphilis, and Borrelia burgdorferi, which causes Lyme disease

Figure 27.17h 5  m Spirochetes Leptospira, a spirochete (colorized TEM)

Cyanobacteria These are photoautotrophs that generate O 2 Plant chloroplasts likely evolved from cyanobacteria by the process of endosymbiosis

Cyanobacteria “Blue-green algae” Only 200 species? In different conditions they grow differently Lots of colors Photosynthetic 7,500 ? species 40  m Oscillatoria, a filamentous cyanobacterium Cyanobacteria

Cyanobacteria were the first organisms on Earth to do modern photosynthesis and they made the first oxygen in the Earth's atmosphere. 3.5 byo O 2 levels increase by 1.5 bya

Stromatolites mainly cyanobacteria 2.8 bya in fossil record Dominant, no herbivores

Mats of cyanobacteria

Red Sea Red-pigmented cyanobacteria floating on the surface Red Sea Saudi Arabia Egypt Iran Turkey

Bad Bacteria!

Bacteria Caused Diseases Bacteria can cause the following diseases: –Tuberculosis –Pneumonia –Strep throat –Staph infections –Scarlet fever –Syphilis –Gonorrhea –Chlamydia –Boils –Tetanus –Lyme disease –Ear infections Many sexually transmitted diseases (STD’s) are caused by bacteria. Gonorrhea Syphilus Chlamydia

E. coli anthrax salmonella Helibacter pilori

Black Band disease

Botulism One group of bacteria called clostridia, can form endospores. Clostridium botulinum, produces a toxin. If canned food is not properly sterilized these endospores can become active inside a can and the disease “botulism” can occur.

Antibiotics Antibiotics are drugs that combat bacteria by interfering with cellular functions –Penicillin – interferes with cell wall production –Tetracycline – interferes with protein production –Sulfa drugs – produced in the laboratory –Broad-spectrum antibiotics will affect a wide variety of organisms

Penicillin, an antibiotic, comes from molds of the genus Penicillium Notice the area of inhibition around the Penicillium.

Bacteria aren’t all Bad!

Root Nodules NifTAL: Nitrogen Fixation of Tropical Agricultural Legumes 50% to 70% of the biological nitrogen fixation Atmospheric N 2 N “fixer” Plant roots

Nitrogen Cycle

Actinomycetes, produce antibiotics such as streptomycin and nocardicin.

Bacteria make Vitamin K

Bacteria put the tang in yogurt and the sour in sourdough bread. Saprobes help to break down dead organic matter. Bacteria make up the base of the food web in many environments. Streptococcus thermophilus in yogurt

Sewage treatment

Oil Spills

Bioluminescence

Bacteria Reproduction Under optimum conditions bacteria can reproduce every 20 minutes. Bacteria reproduction is controlled by various factors including : temperature and food availability.

Bacteria Reproduction Asexual:binary fissionSexual: conjugation

Binary Fission It involves the copying of the DNA and the splitting into two new cells.

Conjugation Sexual reproduction One bacteria is able to transfer its DNA into another bacteria by means of a pilus (pili)

Hansen’s Disease (Leprosy) Mycobacterium leprae

Bubonic Plague January 1900 Yersinia pestis

Antibiotic Resistance Antibiotics- drugs that fight infection caused by bacteria Antibiotic resistance- when bacteria change eliminating the effectiveness of the drug designed to cure or prevent infection. How does it happen? Bacteria survive antibiotic control and continue to multiply into resistant strains.

Timeline of Antibiotic Resistance Alexander Fleming discovers the 1 st antibiotic (penicillin) penicillin available through mass production million lbs of antibiotics produced in the U.S. annually 1960’s- various resistant strains emerging due to abused antibiotic use Today- 50 million lbs of antibiotics produced in the U.S. annually

Antibiotic Resistance How it happens

Diseases that have Exhibited Antibiotic Resistance Gonorrhea Head lice Malaria Methicillin- resistant Staphylococcus aureus (MRSA) Streptococcus pneumoniae Typhoid fever Vancomysin/Glyco peptide intermediate Stapylococcus aureus (VISA/GISA) Vancomycin- resistant Enterococci Tuberculosis

Antibiotic Resistance on Factory Farms Antibiotic Resistance Fish Vaccination