Lab #11 Effects of Atmosphere

A little late- This is info from Lab Practical 1

-streak plate technique was use when applying bacteria to plates

-plates were then incubated in oxygen, low oxygen (or high CO2), 

or NO oxygen and growth was evaluated

-When evaluating growth on plates determine if bacteria is:

Obligate aerobe= aerobic respiration

Obligate anaerobe= fermentation

Facultative anaerobe= aerobic respiration and fermentation

Microaerophile= aerobic respiration

Aerotolerant anaerobe= fermentation 

Thioglycolate broth

Lab 17: Enzymes of Respiration

Catalase Test 

-tests for enzyme catalase which breaks down 

hydrogen peroxide (H2O2) into water and oxygen

-medium= hydrogen peroxide substrate 

-Positive test= bubbles of O2

Oxidase Test 

-tests for enzyme cytochrome c oxidase which is the last component of the electron transport chain in aerobic and some facultative organisms 

-cytochrome c oxidase accepts electrons from cytochrome c (oxidizing it) and donates electrons to oxygen, reducing it into water

medium=BBL DrySlide oxidase Slide w/ reagent 

positive test= purple spot (by ~20sec)

negative= no change

Nitrate Reduction Test 

tests for the ability of an organism to reduce Nitrate (NO3-) to Nitrite (NO2-) using nitrate reductate

also tests for ability to do denitrification= reduce nitrate (NO3-) to Nitrite (NO2-) and eventually reducing it enough to Nitrogen Gas (N2)  using various enzymes 

* note- when reading these tests we start with N2 gas, then Nitrite, then Nitrate

Growth Medium= nitrate broth

Positive Test for N2= bubble

 Negative test for N2= no bubble-and Nitrite test is performed 

Nitrite (NO2-) test

growth medium= nitrate broth

reagents= sulfuric acid (H2SO4) and Tromdorff's reagent (TDR) 

Positive Test= immediate color change to brown/purple -seen on 1st row #6 and #8

Negative Test= no color change and Nitrate Test is performed

Nitrate (NO3-) test

growth medium= nitrate broth

reagents= sulfuric acid (H2SO4), Tromdorff's reagent (TDR) and Zinc

- zinc causes nitrate to be reduced to nitrite 

Positive Nitrate test= immediate change in color to purple/brown 

-seen in #5 second row

Lab 15: Catabolism of Carbohydrates -Fermentation of Carbs Test

Fermentation Of Carbohydrates Test 

tests for Fermentation enzymes

Mediums= glucose (G), Lactose (L), or Sucrose (S)

all tubes contain protein and pH indicator 

(acid= yellow; neutral=green; base= blue)

protein sparring-  if bacteria can't use carbohydrates for metabolism,

 it will use protein which causes the medium to turn blue

Positive Result= if tubes are: yellow +/- bubble 

Key Symbols to Know for Test

A= Acid= yellow color

AG= Acid + Gas= yellow and air bubble

K= alkaline= blue color 

NC= no change

A= Acid= yellow color (ignore middle tube)= Positive Result 

AG= Acid + Gas= yellow and air bubble= Positive Result 

K= alkaline= blue color= Negative Result, and Protein Sparring 

 NC= no change= Negative Result 

Lab 14: Exoenzymes

1. Positive Amylase Test = has a clearing

tests for exoenzyme amylase which hydrolyzes starch (a polysaccharide)

 outside of cell into glucose subunits which can enter cell 

growth medium= starch agar

reagent= iodine- binds to starch

ie #8= positive; #16=negative 

2. Positive Lipase Test =has a clearing 

tests for exoenzyme lipase which hydrolyzes tributyrin (a triglyceride) into 

glycerol and 3 fatty acid subunits which can be taken into cell for energy

growth medium= tributyrin agar -has lipid so it looks white

no reagent 

ie. #8 positive; # 16 negative

3. Positive Gelatinase Test= has a clearing 

tests for exoenzyme gelatinase which hydrolyzes gelatin (a protein) into 

amino acids which can enter cell and be used in metabolism 

growth medium= gelatin agar

no reagent

Bacteria For Lab Practical 1

Here is a list of Bacteria/some other stuff to know for Lab Practical1
 (note names of bacteria are NOT underlined like they should be)

1. Grain Stain
Bacillus subtilis
E. Coli

2. Nonmotile Bacteria
Klebsiella pnemoniae
Micrococcus luteus

3. Secondary Stain
a. Acid Fast Ziehl Neelsen
Mycobacterium smegmatis
Staphylococcus epidermidis
b. Endospore stain= crystal violet method and schaeffer fulton method
Bacillus subtilis
c. Flagella stain= Leifon's Technique with rolling drop slide and mordant
Proteus vulgaris
d. Capsule stain
Klebsiella pneumoniae

4. Colony morphology
Bacillus globigii
Bacillus lincheniformis
Bacillus megaterium
Bacillus mycoides

5. Pigments of Bacteria
Bacillus globigii
Chromobacterium violaceum
Micrococcus luteus
Micrococcus roseus
Pseudomonas aeruginoa
Serratia marcescens
Janothinobacterium lividum

6. Effects of Osmotic Pressure
Staphylococcus epidermidis
Halobacterium salinarium

7. Effects of Temperature
Bacillus stearothermophilus

8. Effects of Atmosphere
Clostridium sporogenes

9. Molds
Spores
Hypha
Hyphae
Mycelium
Spore producing bodies
Penicillilum
Aspergillus
Rhizopus
Coccidiodes

10. Yeasts
Saccharomyces cervisiae
Candida albicans

11. Physical/Chemical control of Growth
Bacillus subtilis (forming endospores)
E. coli
Staphylococcus epidermidis

12. Plasmodial Slime Molds
Physarum polycephalum

13. The Confirmed Test
 E. coli
Enterobacter aeogenes

14. Parasite lab
Plasmodium falciparum
Ascaris lumbricoides
Aedes aegypti mosquito




Good Luck Studying... if i've missed any please let me know : )

Lab 10: Effect of Temperature

#10 Effect of Temp 

-grew different bacteria at different temps to determine min, max, optimum

- min, max, optimum determined by first incubation -growth scaled from 0 (least)-3(most)

min temp= lowest temp in which growth occurred

max temp= highest temp in which growth occurred

optimum temp= temp in which most growth occurred 

- any tubes that had no initial growth were reincubated at optimum to determine if original temp was bacteriostatic or bacteriocidal

Lab 9: Effect of Osmotic Pressure

Parasites Lab

Parasite Lab: Movie “Parasite: Eating us Alive”


1.Parasite= an organism that lives on or in another organism- parasites are detrimental to host

2. Major ways parasites spread:

water, food, vectors

3. Vector= a carrier that transmits parasites from one host to another ex. mosquito

4. Intermediate host= a host that is part of the lifecycle of a parasite

- is needed for development of the parasite and is not the final host

5. Difference bw Vector and Intermediate Host

-both harbor and transmit parasite to host

-Vector= seeks out host ex. mosquito seeks out your blood

-Intermediate host= is just there and it is random if it finds you

6. Ways scientists are trying to Stop/slow spread of Parasites: 

a. Chemicals-can potentially harm environment ex. DDT

b. Water treatment

c. Proper food storage/preparation 

d. Vector control

e. Biological controls=  using one parasite to kill another

f. Vaccines= difficult to produce bc parasites have so many different stages of life with different antigenic markers

7. Parasites can NEVER completely be eliminated bc there are multiple different species that they use as their hosts

8. Plasmodium falciparum= Severe Cerebral Malaria= 

-parasite carried by mosquitoes

-big problem worldwide

-lives in human blood

- can be deadly, especially this form that attacks the brain

Parasites Seen in Our Lab

3 Categories of Parasites

1. Protozoa: ex. Plasmodium falciparum= severe cerebral malaria- we look a blood smear with RBCs containing parasite

2. Helminths (worms) 3 types:

a. Nematodes= roundworms

ex. we look at Ascaris eggs in microscope- Ascaris is a worm that produces eggs with bumps on surface

b. Cestodes= tapeworms

c. Trematodes= flukes

3. Ectoparasites= live/feed on surface of host

ecto= outside

2 types we look at in lab- note only females in these species are parasitic

a. Mosquitos

b. Ticks 

Protozoa= Plasmodium falciparum

Helminths - Ascaris Lumbricoides  Eggs 

Helminths - Ascaris Lumbricoides

Helminths- Cestodes= tapeworms

 these look like little white rice granules

Trematodes- flukes 

Ectoparasites- live/feed on host

Mosquito 

Ectoparasites- live/feed on host

Tick- after feeding 

Tick before feeding 

Lab 40: The Confirmed Test

#40 The Confirmed test 

Introduction

1. Confirmed test= in water testing, is a test done on positive and uncertain presumptive test tubes to confirm the presence of coliform bacteria ex. E. coli

-this test allows you to culture and visualize coliforms

2. In this lab-

-we use streak plate technique to culture bacteria from presumptive test tubes on Eosin Methylene Blue (EMB) agar plates

-Eosin Methylene Blue (EMB) agar plates=

a. redish-purple agar that contains:

1. lactose

                        2. two dyes:

a. Eosin= red

b. Methylene blue 

b. is a differential medium- bc it differentiates coliforms from non-coliforms by dyeing coliform colonies

c. is a selective medium- bc it selects FOR Gram negative bacteria

- the two dyes inhibit Gram positive bacteria 

3. After incubation, you should be able to identify two specific coliform groups and differentiate them from non coliforms

1. E. coli group= typical coliform group 1= Purple with Green metallic sheen

a. these bacteria form colonies that ferment lactose, producing MANY organic acids

b. the acid causes precipitation of a dye complex (methylene blue eosinate) onto the colonies, forming dark  purple colonies with a green metallic sheen 

(precipitation= formation of a solid)

2. Enterobacter aerogenes= typical coliform group 2= Pink/purple colonies

a. these bacteria form colonies that ferment lactose, and produce FEWER organic acids

b. less of the dye complex is precipitated, forming pink/purple colonies 

3. NON-coliforms= colorless colonies

- NON lactose fermenters

- may include fecal bacteria ex. Salmonella and Shigella

-have colorless colonies (which may transmit the reddish purple color of the medium)

Positive test= you have E. coli (purple w. green sheen) or Enterobacter aerogenes (just pink/purple)

Negative test= you don’t and cultures are colorless 

E. coli group =purple with green metallic sheen 

Enterobacter aerogenes group= pink/purple colonies 

Non-coliforms= Colorless

Mixed culture with Enterobacter aerogenes group (purple) and Non-coliforms (little clear dots) 

Lab 41: Standard Plate Count of Soil Bacteria

Colonies made from 1 gram of Soil in different diultions

Lab 39: Presumptive Test

Positive Presumptive test=  yellow (is acidic) and has bubbles 

Negative Presumptive test= blue (basic)  OR yellow with no bubbles

Lab 23: Plasmodial Slime Molds

Plasmodial Slime Molds of Physarum polycephalum  or “many headed slime”