Microbiology Exam 5

Know the microbial realtionships

• symbiosis

• mutalism

• commensalism

• antagonism

• competition

• parasitism

• predation

What is the flow of energy and water in order

• sun (ultimate source of energy)

  • exception - chemolithotrophic (inorganic energy - atomic)

• primary producers

  • autotrophs - energy from sun

    • photosynthetic bacteria, cyanobacteria, protists, algae

• consumers

  • heterotrophs - hetrotrophic bacteria, protisits, fungi, viruses - eat producers or consumers (every level down lose 10%)

    • 1, 2, 3 degree consumers

• Decomposers - eat dead bodies or waste products

  • numerous fungi and bacteria

  • detritus

What is the carbon cycle

• carbone dioxide fixation

  • photosynthesis

  • chemosynthesis

• forms in carbon in soil

  • derived from plant material

    • cellulose and hemicellulose

    • lignin

    • waxes

    • phenolic compounds

What is the nitrogen cycle

• mainly terrestrial cycle

• nitrogen cycled in series of microbially-mediated oxidation and reduction reactions

• 4 main forms nitrogen: dinitrogen gas (N2), organic nitrogen (amino acids), ammonia (NH3), nitrate (NO3-)

• Detrification: NO3 > N2

• Nitrificaton: NH3 > NO2 > NO3

• Ammonification/Deammonifcation: amino acids > NH3 ammonia

What is nitrogen fixation and its 2 types, and what are the 3 methods used to fix nitrogen

Nitrogen fixation: N2 + 3H2 > 2NH2

• industrial, lightening, biological nitrogen fixation

2 types:

• Non-symbiotic nitrogen fixation (free living microorganisms)

  • important in flooded rice fields, rock surfaces, and nitrogen deficient soils

    • microorganisms: Axotobacter, Clostridium, Cyanobacteria

• Symbiotic nitrogen fixation (association of microorganisms with another organism)

  • association - a nitrogen fixing microorgansim with a plant

  • important: soils where fixed nitrogen is insufficient for more than one growing season

  • Rhizobium - legume

  • Anabaena (cyanobacteria) - azolla (fern)

  • Frankia (actinomycetes) - alder tree

Industrial Nitrogen Fixation

Haber-Bosch process

• fixes nitrogen (typically water) under high temps and pressures

• source of most fertilizer nitrogen

  • main forms of fertilizer nitrogen are ammonium, nitrate, urea, diammonium phosphates

Lightening Nitrogen Fixation

energy from lightening

• sufficient to oxidize dinitrogen to nitrogen oxides

• major global contributer of fixed nitrogen

Biological Nitrogen Fixation

• requires lots of energy

• requires 12 ATPs per NH3 fixed

  • 4 ATPs per bond broken by enzyme nitrogenase (works w/o O2)

What are the names of organisms that fix nitrogen (non symbiotic and symbiotic)

• Non-symbiotic

  • clostridium

  • azobacter

  • cyanobacteria

• Symbiotic

  • rhizobium - legume

  • anabaena (cyanobacteria) - azolla (fern)

  • frankia (actinomycetes) - alder tree

What is the symbiotic relationship of Rhizobium, anabaena, and frankia have with their plants

How does Rhizobium form nodules on legumes

Legumes

• soybeans

• peas, vetch, sweetpea

• alfalfa, sweet clover

• beans

• lupines

• clover

How does decompistion take placee and under what conditions will it proceed faster or slower

• plant and animal microbial resides

  • proteins in soil

• proteins undergo proteolysis

  • amino acids

• most nutrients go through living microbial biomass before accessible to other organisms

  • heterotrophs

• aerobic conditions decompistion faster and more complete and anaerobic slower

  • deamination/ammonification: degredation of amino acids and release of ammonia

What are the nitrogen compounds that are useable to plants

ammonium (NH4) and nitrate (NO3-) most useable to plants

What is the difference between nitrification and dentriification and organisms that are responsible for each

Nitrification (ammonia oxidation)

• NH3 > NO2- > NO3-

  • 2 step process

    • ammonia converted into nitrate (NO2-) —- nitire toxic to plants

    • aerobic process

    • oxidation of nitrite inhibited by ammonium

    • chemolithotrophic microorganisms or some heterotrophs

  • NH3 > NO2-nitrosomoas

  • NO2- > NO3- nitrobacter

Dentrification (nitrate reduction)

• NO3- > NO2- > NO > N2O > N2

• mineral nitrogen (NO3-) reduced to dinitrogen gas (N2)

• anaerobic process (O2 poor soils)

• heterotrophic organisms using nitrate as terminal e- acceptor: anaerobic respiration (breath nitrate)

  • pseudomonas, thiobacillus, micrococcus species

  • removes nitrates and interfers with plant growth

What is the sulfur cycle and organisms involved with sulfur reducing and sulfur oxidizing

Sulfur reducing

• SO4 > H2S

• mainly aquatic

• occurs in deep water (anaerobic) — warm springs

• sulfate reducing bacteria:

  • deusulfovibrio, desulfomonas, desulfotomaculum

• reduce SO4² to H2S

• anaerobic process SO4²- final e- acceptor

Sulfur oxidizing

• S2 > SO4

• aerobic

• occurs in mines, soil

• plants use SO4 to make amino acids

How do microbes transmit in the air and the condition that affect their survival

air very inhospitable for microorganisms, need a ride

• dust particles, water, sputum, or aerosol droplets

• some droplet nuclei may exsist for hours or days

• spores - molds and bacteria, bacillus subtilis (200 year survival)

Factors:

• humidity

• temperature

• sunlight

• size of particles harboring microorganisms

• formation of cysts and spores

Paricles come from:

• soil (wind picks up dust)

• oceans (wind creates sprays)

• Industry, agriculture, and municipal facilities can create aerosols

  • water treatment plants

  • irrigation

How do we control airborne microbes

• to spray in air: Triethylene glycol, resorcinol, lactic acid

• UV raditation

• filtration (laminar airflow)

  • HEPA filters

Where do most microbes live in soil and the general makeup of microbe population

• most found in topsoil/humus layer

  • 97% bacteria and 3% fungi

What are the factors affecting soil microbes

• moisture

• oxygen

• pH

  • optimum 6-8

• temperature

What are the soil pathogens

• clostridium tetani (tetanus)

• clostridium botulinum (botulism)

• clostridium pefringens (gas gangrene)

• bacillus anthracis (anthrax)

What are the factors affecting microbes in an aquatic environment

• temp

• hydrostatic pressure

• light

• salinity

• turbidity

• pH

  • fresh 2-9

  • ocean 6.5-8.3 (alkaline)

• Nutrients

What is the oxygen compisition in water and soil

too much water promotes dentrification, and the balance and breakdown or organic material promotes nitrification for healthy microbe environment in soils

What are the organisms in a marine environment

• phytoplankton, cyanobacteria, algae, diatoms, dinoflagellates

• gram (-) bacteria

  • pseudomonas, vibrio, arcobacter, flavobacterium

• marine fungi and protozoa

• ocean environment oligotrophic (nutrient poor)

What is an oligotrophic environment

few nutrients available for organisms to use for growth

What are the steps of water purification and what does each step do

1. allum (aluminum potassium sulfate) - filtering system, clumps

   1. flocculation

2. filtration

   1. beds of sand or charcoal

3. Chlorination

   1. kills bacteria and some viruses

What is the multiple tybe test for water purity

1. presumpitive test - ferments lactose into acid and gas

2. confirmed test - streak from lactose broth onto EMB and incubate for E. coli growth

3. completed test - select typical coliform colonies (e. coli) and innoculate in lactose broth and incubate 24 hrs

   1. coliform = + test

Why is E. coli a good indicator organism for water quality

• present in polluted water

• present when pathogens present

• quantity correlates with number of pathogens

• survives better than pathogens

• has uniform and stable properties

• generally harmless to humans

• present in greater numbers than pathogen

• easily detected in a lab

What are the pathogens transmitted in water

• salmonella typhi (typhoid fever)

• campylobacter fetus (gastroenteritis)

• vibrio cholerae (asiatic cholera)

• vibrio parahaemolyticus (gastroenteritis)

• E. coli (gastroenteritis)

• Shigella species (shigellosis)

• Poliovirus (poliomyelitis)

• balantidium coli (balantidiasis)

• entamoeba hist (amoebic dysentery)

• Hep A virus

What are the steps to sewage treatment

1. Sedimentation

   1. screens to filter out larger items

   2. settling tank for sludge

2. filtration

3. Chlorination

   1. nitrogen stripping

   2. preciptation

What are the different kinds of pesticides and what do they kill

• herbicides: control of weeds

• insecticides: insects

• fungicides: fungi

• nematicides: nematodes

What is biremediation and what are the factors that influence the breakdown of pesticides

Bioremediation: use of microorganisms to clean up pollutants

depends on:

• complexity of molecule w/ presence of halogens, such as chlorine atoms in molecule

• presence and number of microorganisms capable of degrading pesticide

• presence of other nutrients

• concentration of pesticide

What is the effect of chlorine (PCB) on breakdown of molecules

• pesticide residues in foods and drinking water

• ozoone, nitrogen, and sulfur oxides

• heavy metals

What is the fungus to break down PCBs, heavy metals, and TNT

phanerodchaete chyrsosporium (white rot fungus)

what is the bacteria that breaks down PCBs and where are they found

chlorinated biphenyls > (actinobacter) > chlorobenzoic acid > (pseudomonas) > cells + Cl-

found in soil

What are the microbes found on grains

molds

• claviceps purpurea (ergot)

  • hallucinogenic - deadly

• aspergiullus flavis

  • alflatoxins - mutagens (one of most potent toxins known to man) - carcinogens

• rhizopus nigricans

• penicillum, aspergillus, chrysonilia sitophilia (formerly pink bread mold)

What are the microbes found on fruits and vegtables

• pseudomonds

• salmonella, shigella, entamoeba histolytica, ascaris

• viruses

• skin of fruits and vegtables

  • waxes w/ antimicrobial substances

• leafy vegtables

  • erwinia carotovora

    • soft rot on leaves and potatoes

  • phytophthora infestans (water mold)

    • irish potato blight (famine 1846)

  • Fruits

    • bacteira: Fusarium, Rhizopus, Penicillin

    • fungi: Leuconostoc, Lactobacillus

What are the microbes present on meats and poultry

• molds -rhizopus, mucor (white fluffy growth)

• bacteria

  • pseudomonas mephitica - green color w/ stink (H2S)

  • clostridium spp. - bone stink

• ground meats

  • lactobacilli - helps retard growth of pathgoens

  • molds - rhizopus, mucor

• pork

  • trichnella sprialis (helminth) trichinosis

• Poultry

  • more than 20 pathogens

    • 50% salmonella, 25% clostridium perfringens, 25% staphylococcus aures

    • pseudomonds (slime)

• Eggs

  • salmonella

  • fungi

• Fish and Shellfish

  • salmonella typhimurium, vibrio cholera

    • filter feeders -filter sewage

• Crabs and Shrimp

  • clostridium botulinum, cryptococcus, candida

    • growth before processing

What are the organisms in fresh and sour milk including pathogens and non pathogens and what diseases do these cause

Fresh Milk

• staphylococcus epidermis, micrococcus, pseudomonas, flavorbacterium, erwinia

  • Spoilage organisms: E. coli, Acinetobacter johnsoni

• Mycobacterium bovis (TB)

• Brucella spp. (brucellosis or undulant fever)

  • testing and vaccination have elimianted these pathogens

• staphylococcus aureus, salmonella

Sour milk

• streptococcus lactis, lactobacillus spp.

Why is honey dangerous for a small baby

clostridium botulinum and other toxins present

What are the pathogens in food and milk and the disease that they cause

• staphylococcus aureus (food poisoning)i

• Clostridium perfringes (food poisoning)

• bacillus cereus (food poisoning)

• clostridium botulinum (botulism)

• Salmonella species (Salmonellosis)

• Shigella species (Shigellosis)

• Enteropathogenic and E. coli (Montezuma’s revenge + other diseases)

• Campylobacter (Gastroenteritis)

• Virbio cholera (cholera)

• Vibrio parahaemolyticus (asian food poisoning) 

What are the 3 kinds of canned food spoilage and how to recognize them

• Thermophilic anaerobic spoilage

  • gas and acid - bulging and blackened can

• Flat Sour Spoilage

  • acid - blackened can

• Mesophilic spoilage

  • improper canning and broken seal

Canning

• moist heat under pressure (autoclave)

• kills most endospores

  • bacillus stearothermophilus

  • bulging cans, gas production, seals broken

Why is bacillus stearothermophilus important in canning

highly heat resistant bacterium causes flat sour spoilage makes it key organism for monitoring effectiveness of sterilizing process

What is the preservation process behind jams, jellies, refrigeration, freezing, drying, and lyophilization, and the effect if any on microbes

Jams & Jellies

• osmotic pressure

  • sugar and artifical sweetners

Refrigeration and Freezing

• 4 C and -10 C

• does not destroy most microbes

• freeze thawing promotes growth of organisms

Drying & Lyophilization

• oldest method

• 90% H2O removed

• stops growth - does not kill

• addition of salt, sugar, or chemical preservatives alters osmotic pressure

• water activity is measure of available water

  • water activity of .90 inhibits most bacteria from growing

  • water activity of .85 required to inhibit staphylococcus aureus

What are the types of radiation and the benefits and drawbacks of each

• UV (nonionizable)

  • surface, poor penetration

• Microwave (nonionizable)

  • cooking and food prep but not preservation

• Gamma rays (ionizable)

  • penetrates well

  • vitamins destoryed

  • formaldehyde - benzene are formed

  • alters taste of food

What are the chemical additives to food and how do they work

• organic acids

  • benzoic, sorbic, proprionic

• alkylating agents

  • ethylene oxide, propylene oxide

    • nuts and spices

• sulfur dioxide

  • dried fruits

• ozone

  • beverages and shellfish

• NaCl - osmotic pressure

What are the beneftis of using nitrates on meat and why is it dangerous

nitrates and nitrites > nitroamines (carcinogen)

keeps meat red

What is a natural occuring antibiotic in foods and organisms that produces it

nisin — streptococcus lactis

Why are antibiotics not used much to preserve food

To prevent/to avoid:

• good santitation techniques

• resistance development

• allergic rxns

• desired fermentation

How is milk pasteruized and sterilized

HTST (High Temp Short Time) - flash

• 71.6 C for 15 sec

LTLT (Low Temp Long Time) - holding

• 62.9 C for 30 min

UHT (Ultra High Temp) - sterilized

• 90 C for 3 sec

• alters flavor

What advantages do yeast and algae have as food sources

Yeast

• proteins and vitamins

• grow on waste materials - sewage

Algae

• scendesmus and chlorella

• shortens food chain

• treated sewage

What is the organism used to make bread and sour dough bread

Yeast - saccharomyces cerevisiae

sour dough - proprionic bacteria

What are the organisms used to make yogurt

• streptococcus thermophilus

• lactobacillus bulgaricus

• lactobacillus acidophilus

What is the process behind cheese production and organsims used to make cheese

• lactic acid bacteria

• rennin

  • enzyme from calf stomachs

• curd and whey

Which organisms are involved in Roquefort and blue, swiss, brie, and cheddar

• Roquefort and Blue: S. lactic, S. cremoris, Brevibacterium linens

• Swiss: S. lactis, S. thermophilus, S. helveticus, Propionibacterium shermani, or L. bulgaricus and P. freudenreichii

• Brie: S. lactis, S. cremoris, Penicillium camemberti

• Cheddar: S. lactis, S. cremoris, Brevibacterium linens

What is the symbiotic relationship Rhizobium, Anabaena, and Frankia have with their plants

Rhizobium

• mutalistic relationship with legumes

• converted N2 > NH4 (ammonia) in root nodules in exchange for carbs and shelter

Frankia

• mutalisitc relationship with non-leguminous actinorhizal plants

• creates root nodules to fix nitrogen for plants and recieve sugars from it

Anabaena

• Forms symbiotic relationship with plants

• fixes nitrogen for plant and in return receives protection and other benefits like plant growth regulators

How does a Rhizobium form nodules on legumes

• attatchment of rhizobia to surface of root hair

• penetration of rhizobia into deformed root hair

• formation of infection thread of bacteria from root hair to root cortical cells

• formation of nodule containing bacteriods

  • very specific interaction

  • anaerobic environment inside nodule