Bacteria Survival

1. Bacteria Survival • Endospore- • a thick celled structure that forms inside • the cell • they are the major cause of food poisoning • allows the bacteria to survive for many years • they can withstand boiling, freezing, and extremely dry conditions • it encloses all the nuclear materials • and some cytoplasm 1

2. Bacteria Survival Bacillus subtilis Endospore-the black section in the middle • highly resistant structures • can withstand radiation, UV light, and boiling at 120oC for 15 minutes. 2

3. Microbe Survival – Food sources • parasites–microbe that feed on living things • saprophytes–use dead materials for food (exclusively) • decomposers –get food from breaking down dead matter into simple chemicals • important- because they send minerals and other materials back into the soil so other organisms can use them 3

4. Beneficial Microbe • “What is soil, becomes grass, becomes a cow, becomes you and me and then becomes soil again. Without microbes, the whole ecosystem would collapse”

5. Importance of Microbes • Life is microbial! (to the first approximation) • Micro-organisms colonise every environment on earth • >80% of life’s history was bacterial • You have more bacterial cells than human cells • Microbes play a key role in the biosphere • Pathogenic microbes globally are the most important cause of human disease and death

6. Are all Microbe pathogens? No, most are harmless Some are even helpful Examples of helpful bacteria: Lactobacillus: makes cheese, yogurt, & buttermilk and produces vitamins in your intestine Leuconostoc: makes pickles & sauerkraut Pediococcus: makes pepperoni, salami, & summer sausage

7. The Importance of MOs Most microbes are not harmful! In fact, a large number have beneficial effects Human health (historical) Environmental recycling Industrial applications Mining, Agriculture Human health (contemporary) Biotechnology Food/beverage commodities primary producers

8. Microbes and Agriculture Certain soil bacteria live symbiotically in the roots of legumes (Rhizobium) Convert N2 to NH3 provides amine for aa’s Mycorrhizal fungi and enhanced plant vigor Also, bacteria in rumens of cattle, sheep benefit these animals in breakdown of cellulose

9. Importance of microbes in food production Bread Beer & Wine Yogurt Pickles Sauerkraut Cheeses Kim-chi Production of vitamins, amino acids, flavors

10. A Closer Look – Helpful Bacteria Pediococcus - used in production of fermented meats Lactobacillus casei – found in human intestines and mouth to improve digestion Leuconostoc cremoris – used in the production of buttermilk and sour cream Lactobacillus bulgaricus – used in the production of yogurt

11. Mineral and energy related industries involving MOs Natural gas (methane) is a product of bacterial action Will be discussed in Archaebacteria section Anaerobic, methanogens Crude oil is subject to microbial ATTACK. In fact crude oil is a product of microbial planktonic algae zooplankton Drilling *All of these require Recovery methods which minimize Storage microbial damage.

12. Other important roles cont’d Biogeochemistry oil production/degradation soil genesis harvest gold reduce sulfur in oil Chemical production Food additives, citric acid, lactic acid, xanthan gum, MSG Chemicals, alcohols, glycerol, dextran, biocontrol agents, proteases, antioxidants

13. MOs can produce natural proteins Insulin-lowers blood sugar Interferon-an anti-viral substance Factor VIII-substance for clotting blood; missing in hemophiliacs Streptokinin -a substance used to dissolve blood clots in coronary arteries Beta endorphins-pain suppressors

14. impact of microorganisms on human affairs:

15. Fermentation

16. Microbes and Agriculture • Nitrogen fixation 1. association between plants (legumes) and bacteria 2. reduce need for fertilizer • Rumen microbes in cattle and sheep allow them to breakdown/digest grass and hay • Nutrient cycling (C, N, and S) • Plant and animal diseases

17. 1. Microorganisms and Food • prevent microbial spoilage of food and food borne disease • Manufacturing of foods 2. Microorganisms, energy and environment • Natural gas (methane) • Ethanol (biofuel) • Bioremediation 3. Microbes and the future • Biotechnology-genetic engineering

18. The Alphaproteobacteria • Nitrogen-fixing bacteria • Rhizobium • Fix nitrogen in the roots of plants Figure 27.5, step 5

19. The Nitrogen Cycle Figure 27.4

20. Nitrogen Cycle Microbial decomposition Proteins and waste products Amino acids Microbial ammonification Amino acids (–NH2) Ammonia (NH3) Nitrosomonas Ammonium ion (NH4+) Nitrite ion (NO2- ) Nitrobacter Nitrite ion (NO2-) Nitrate ion (NO3- ) Pseudmonas Nitrate ion (NO3-) N2 Nitrogen - fixation N2 Ammonia (NH3)

21. The Sulfur Cycle Figure 27.7

22. Decomposition by Microbes Bioremediation Use of microbes to detoxify or degrade pollutants; enhanced by nitrogen and phosphorus fertilizer Bioaugmentation Addition of specific microbes to degrade of pollutant Composting Arranging organic waste to promote microbial degradation Figure 27.9

23. Decomposition by Microbes Figure 27.10

24. Harmful Bacteria • some bacteria cause diseases • Animals can pass diseases to humans • Communicable Disease – • Disease passed from one organism to another • This can happen in several ways: • Air • Touching clothing, food, silverware, or toothbrush • Drinking water that contains bacteria 24

25. What are some common pathogens? Pathogenic E. coli (like O157:H7) Found in ground beef, contaminated fruits and vegetables Salmonella Found in raw meats, poultry, eggs, sprouts, fruit and vegetables Listeria Found in deli foods, lunch meats, smoked fish and vegetables E. coli O157:H7 Salmonella Listeria

26. Examples of Pathogens Salmonella E. coli O157:H7 What shape are these bacteria? Cocci, bacilli, or spiral? Staphylococcus aureus Campylobacter jejuni

27. Infection and Disease • Infection the entry of a microbe into the host. • Disease infection followed by the appearance of signs and symptoms. • Pathogen an infectious or disease agent. • Saprobe a microbe that lives on dead or decaying organic matter. • Opportunistic pathogen is a microbe that cause disease in immunocompromised hosts or when the normal microbiota is altered.

28. Medically-important Endospore-forming Bacteria • Bacillus anthracis causes anthrax • Bacillus cereus causes food poisoning • Clostridium tetani causes tetanus • Clostridium botulinum causes botulism • Clostridium perfringens causes food poisoning and gas gangrene • Clostridium difficile causes antibiotic-induced diarrhea and pseudomembranous colitis

29. Koch’s Postulates (1884) • Suspect pathogenic organism should be present in all cases of the disease and absent from healthy animals • Suspect organism should be grown in pure culture • Cells from a pure culture of suspect organism should cause disease in healthy animal • Organism should be reisolated and shown to be same as the original

31. Controlling Microbe 3 ways to control bacteria: 1) Canning-the process of sealing food in airtight cans or jars after killing bacteria • endospores are killed during this process 2) Pasteurization-process of heating milk to kill harmful bacteria 3) Dehydration-removing water from food • Bacteria can’t grow when H2O is removed • example: uncooked noodles & cold cereal 31

32. Controlling Microbe Antiseptic vs. Disinfectants Antiseptic- chemicals that kill bacteria on living things • means – “against infection” Examples: iodine, hydrogen peroxide, alcohol, soap, mouthwash Disinfectants- stronger chemicals that destroy bacteria on objects or nonliving things 32