Archaebacteria and Eubacteria

1. Archaebacteria and Eubacteria

2. Bacteria are of immense importance because of their rapid growth, reproduction, and mutation rates, as well as, their ability to exist under adverse conditions. • The oldest fossils known, nearly 3.5 billion years old, are fossils of bacteria-like organisms.

3. Bacteria can be autotrophs or hetertrophs. • Those that are classified as autotrophs are either photosynthetic, obtaining energy from sunlight or chemosynthetic, breaking down inorganic substances for energy .

4. Bacteria classified as heterotrophs derive energy from breaking down complex organic compoundsin the environment. This includes saprobes, bacteria that feed on decaying material and organic wastes, as well as those that live as parasites, absorbing nutrients from living organisms.

5. Depending on the species, bacteria can be aerobic which means they require oxygen to live or • anaerobic which means oxygen is deadly to them. Green patches are green sulfur bacteria.  The rust patches are colonies of purple non sulfurbacteria.  The red patches are purple sulfur bacteria.

6. CH4 1. Methanogens Archaebacteria • use carbon dioxide, nitrogen gas, or hydrogen sulfide as a source of energy • produce methane (natural gas) as a waste product • anaerobes – live in oxygen free environments (such as swamps, marshes, and sewage disposal plants)

7. 2. Halophiles • salt-loving • live in extremely saline environments such as the Great Salt Lake of Utah (picture on left) or salt ponds on the edge of San Francisco Bay • must live in high salt concentrations that may reach up to 15% (seawater is 3.5% salt)

8. Extreme halophiles can live in extremely salty environments. Most are photosynthetic autotrophs. The photosynthesizers in this category are purple because instead of using chlorophyll to photosynthesize, they use a similar pigment called bacteriorhodopsin that uses all light except for purple light, making the cells appear purple.

9. 3. Thermoacidophiles • heat- and acid- loving • live in extremely hot and acidic environments • some species live in hot sulfur springs (low pH) and use sulfur as their source of energy • others prefer spots on volcanoes, or near deep sea vents, and grow best at temperatures above 80 degrees celsius

10. Thermophiles These are Archaebacteria from hot springs and other high temperature environments. Some can grow above the boiling temperature of water. They are anaerobes, performing anaerobic respiration. Thermophiles are interesting because they contain genes for heat-stable enzymes that may be of great value in industry and medicine. An example is taq polymerase, the gene for which was isolated from a collection of Thermus aquaticus in a Yellowstone Park hot spring. Taq polymerase is used to make large numbers of copies of DNA sequences in a DNA sample. It is invaluable to medicine, biotechnology, and biological research. Annual sales of taq polymerase are roughly half a billion dollars.

11. Eubacteria Cyanobacteria This is a group of bacteria that includes some that are single cells and some that are chains of cells. You may have seen them as "green slime" in your aquarium or in a pond. Cyanobacteria can do "modern photosynthesis", which is the kind that makes oxygen from water. All plants do this kind of photosynthesis and inherited the ability from the cyanobacteria.

12. Cyanobacteria were the first organisms on Earth to do modern photosynthesis and they made the first oxygen in the Earth's atmosphere.

13. Other Bacteria live symbiotically in the guts of animals or elsewhere in their bodies. For example, bacteria in your gut produce vitamin K which is essential to blood clot formation. Still other Bacteria live on the roots of certain plants, converting nitrogen into a usable form.

14. 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

15. Bacteria can reproduce asexually by binary fission.

16. Bacterial conjugation is the transfer of genetic material between bacteria through direct cell to cell contact, or through a bridge-like connection between the two cells Sometimes referred to as sexual reproduction because it involves 2 cells instead of one Antibiotic resistant plasmids can be passed on – not good! Bacterial Conjugation

17. Shapes of Bacteria Arrangements: Also mono = single * Add these arrangements to your D10

19. Bacteria Summary • They are living cells that have a cell wall, capsule, cytoplasm, and ribosomes • Genetic material is in the form of a single chromosome (and possibly an additional plasmid) • They are unicellular, prokaryotic and do not have membrane-bound organelles • They may be anaerobic or aerobic. • Archaebacteria are classified based on the type of environment they inhabit • Eubacteria are classified based on the shape or on their source of energy.

20. Penicillin, an antibiotic, comes from molds of the genus Penicillium Notice the area of inhibition around the Penicillium. Penicillin kills bacteria by making holes in their cell walls. Unfortunately, many bacteria have developed resistance to this antibiotic. Antibiotics

21. Antibiotics-Resistance • Bacterial resistance to antibiotics comes from genes found on the plasmid (circular DNA piece). • Since bacteria reproduce so quickly, thus there is a high rate of mutation in the plasmid to create antibiotics-resistance. • Remember that antibiotics cannot kill viruses. • Also, remember that the human immune system naturally kills bacteria by engulfing them via phagocytosis.

22. The Gram stain, which divides most clinically significant bacteria into two main groups, is the first step in bacterial identification.  • Bacteria stained purple are Gram + - their cell walls have thick petidoglycan and teichoic acid. • Bacteria stained pink are Gram – their cell walls have have thin peptidoglycan and lipopolysaccharides with noteichoic acid.

23. Gram (+) organisms are more susceptible to Penicillin than Gram (-).Gram (+) bacteria include causative organisms of anthrax, rheumatic fever, diphtheria, botulism, etc.Gram(-) bacteria are identified as causative agents of cholera, typhoid, dysentery, whooping cough, some food poisonings, bubonic plague, etc.

24. Thus, the importance of determining the Gram (+) and the Gram(-) bacteria. This is how the physician will determine the diagnosis and treatment.The Gram (+) and Gram (-) bacteria will require different certain antibiotics to eradicate the bacteria. Some are susceptible to a particular antibiotic and some are resistant the the same antibiotic. This is how the physician decides which antibiotic to administer or prescribe.

25. In Gram-positive bacteria, the purple crystal violet stain is trapped by the layer of peptidoglycan which forms the outer layer of the cell. In Gram-negative bacteria, the outer membrane of lipopolysaccharides prevents the stain from reaching the peptidoglycan layer. The outer membrane is then permeabilized by acetone treatment, and the pink safranin counterstain is trapped by the peptidoglycan layer.

26. The Gram stain has four steps: • 1. crystal violet, the primary stain: followed by • 2. iodine, which acts as a mordant by forming a crystal violet-iodine complex, then • 3. alcohol, which decolorizes, followed by • 4. safranin, the counterstain.

28. Is this gram stain positive or negative? Identify the bacteria.

29. Is this gram stain positive or negative? Identify the bacteria.

30. Foodborne Pathogens • Remember the pneumonic FATTOM • F - Food - There are sufficient nutrients available that promote the growth of microorganisms. Protein-rich foods, such as meat, milk, eggs and fish are most susceptible. • A - Acidity - Foodborne pathogens require a slightly acidic pH level of 4.6-7.5, while they thrive in conditions with a pH of 6.6-7.5. FDA regulations for acid/acidified foods require that the food be brought to pH 4.5 or below. • T - Temperature - Foodborne pathogens grow best in temperatures between 41 °F (5 °C) to 135 °F (57 °C), a range referred to as the temperature danger zone (TDZ). They thrive in temperatures that are between 70 °F (21 °C) to 120 °F (49 °C).

31. FATTOM • T - Time - Food should be removed from "the danger zone" within two hours, either by cooling or heating. While most guidelines state two hours, a few indicate four hours is still safe. • O - Oxygen - Almost all foodborne pathogens are aerobic, that is requiring oxygen to grow. Some pathogens, such as clostridium botulinum, the source of botulism, are anaerobic and do not require oxygen to grow. • M - Moisture - Water is essential for the growth foodborne pathogens, water activity (wa) is a measure of the water available for use and is measured on a scale of 0 to 1.0. Foodborne pathogens grow best in foods that have a wa between 1.0 and 0.86. FDA regulations for canned foods require wa of 0.85 or below.

32. Endospore • Bacteria can survive unfavorable conditions by producing an endospore.

33. Clostridium botulinum(food-poisoning) • Clostridium botulinum is an anaerobic, Gram+, spore-forming rod that produces a potent neurotoxin (that can be destroyed if heated at 80°C for at least 10 minutes). • The spores are heat-resistant and can survive in foods that are incorrectly or minimally processed. • Four types of botulism are recognized: foodborne, infant, wound, and undetermined classification. • Symptoms occur usually 18-36 hours (sometimes 4 hours – 8 days) after ingestion of the food containing the toxin. • Early signs include marked lassitude, weakness and vertigo, usually followed by double vision and progressive difficulty in speaking, swallowing and breathing, weakness of other muscles, abdominal distention, and constipation.

34. How do these Food Preparation Methods utilize FATTOM? • Cooking • Freezing • Dehydrating • Pasteurizing • Refridgerating • Canning • Preservatives • Radiation • Smoking • Chlorination • Salting • Vacuum sealing

35. Homework Fun • Questions on D10 • Read section 2.2 • 2.2 LC #7-12 pg 62 • 2.2 rev #1-12 pg 66 • Read D15-D18 Antibacterial resistance