Bacteria Morphology

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					   USING BACTERIA MORPHOLOGY
CHARACTERISTICS TO STUDY BACTERIAL
            DIVERSITY.
            092404 EMJT


         By Ellie Masserrat
              Pian Lu
           John Taucher
                          Bacteria…?
                                                    Leptospira, causes serious disease in livestock




   Bacteria are often viewed as the cause of diseases in humans and animals.

   Some bacteria are useful, for example certain bacteria aids in digestion.

   Bacteria make up the base of the food web in many environments.

   Bacteria are of such immense importance because of their extreme
    flexibility, capacity for rapid growth and reproduction, and great age.

   They can be photosynthetic, using light, or chemosynthetic, using inorganic
    chemicals as the source of energy, but most are heterotrophic, absorbing
    nutrients from the environment.
Background Information
Prokaryotes



   Prokaryotes represent two domains, bacteria
    and archaea.

   Archaea live in Earth’s extreme environments.

   Bacteria are the most abundant and diversified
    organisms on Earth.
                 Bacterial Structure
   Biochemical processes that
    normally occur in a chloroplast
    or mitochondrian of eukaryotes
    will take place in the inner
    membrane of prokaryotes.

   Bacterial DNA is circular and
    arrayed in a region of the cell
    known as the nucleotide .

   Scattered within bacteria’s
    inner membrane are numerous
    small loops of DNA known as
    plasmids .
Structure
        Some bacteria have
         flagella with a different
         microtubule structure than
         the flagella of eukaryotes..
        Ribosomes are the
         structures in cells where
         proteins are assembled.
        Bacterial ribosomes have
         different sized ribosomal
         subunits than do
         eukaryotes.
Bacteria Have One of Three
      Cellular Shapes
                Rods (bacilli)




                Coccoid-Shaped




                Spirilla
Reproduction
         Prokaryotic cell division is
          binary fission.
           –   Single DNA molecule that first
               replicates.
           –   Attaches each copy to a
               different part of the cell
               membrane.
           –   Cell begins to pull apart.
           –   Following cytokinesis, there
               are then two cells of identical
               genetic composition.
Now…On to our experiment...
   Purpose: Identify varieties of bacterial colonies and investigate
    bacterial species diversity, by isolating, culturing, and analyzing
    bacterial colonies, or species, that inhabit:
            Air
            Pond Water
            Raw Chicken
            Washed/Unwashed hands
            Keyboard
            Soil Sample

   Hypothesis: Knowing that bacteria can thrive in almost anywhere
    on our planet, we reason that all of the environments tested will
    grow bacterial species. We further hypothesize that the thumb
    print of the washed hand with the anti-bacterial soap, should
    house less species than any others tested, because the anti-bacterial
    soap should kill off all bacteria.
                                           Methods
                                                           For chicken, soil, pond water,
                                     A
                                                            and keyboard samples, streak
                                     .                      the plate using the streak plate
                                                            method to isolate bacterial
                                                            colonies.
                                                           Leave agar plate open for air
                                   B.                       sample.
                                                           For the unwashed hand gently
                                                            press thumb against agar.
                                                           Take washed hand and gently
                                     C.                     press thumb against agar.
                                                           Wrap in Parafilm and incubate
                                                            the cultures for about one week
Figure 1.   Streak Plate Method. (a) Streak the
plate back and forth across top half of plate. (b)          at 22 C.
Rotate plate a quarter turn counter clockwise and          Observe and Interpret Data
streak top right quarter of plate. (c) Rotate plate a
quarter turn counter clockwise and streak top right
quarter of plate again.
            Results: Soil
SIZE   SHAPE             MARGIN        SURFACE      COLOR

4 mm    Irregular        Lobate         Wavy      Yellow/white

3 mm    Irregular        Lobate        Wrinkled   Brown/yellow

5 mm   Filamentous   Filamentous       Wrinkled   Green/white




                                   2
                     1

                      3
    Results: Pond Water
    Size Shape         Margin   Surface Color
#
1   2 mm round         smooth   Smooth      grey
2   2 mm round         lobate   contoured   beige
3   1 mm round         Smooth   Smooth      clear



                      2.

    1.
                 3.
            Results: Raw Chicken
 #   Size   Shape       Margin   Surface     Color
1    2mm    Irregular   lobate   contoured   yellow/green
2    3mm    irregular   lobate   wrinkled    clear/white
3    1mm    round       Smooth   Smooth      Yellow/green
4    2mm    Irregular   wavy     contoured   brown


                                             1.
                                                        3.
                                                  2.

                                                   4.
                                Results: Air
            #        Size        Shape      Margin Surface       Color
            1       5 mm        Irregular   Smooth Smooth Yellow/orange
            2       5 mm         Round      smooth contoured Yellow/orange
            3       1 mm        Irregular    Wavy contoured Yellow/white
            4       3 mm        Irregular   Lobate wrinkled Yellow/brown
            5       3mm         Irregular   Lobate   smooth      White
            6       5 mm          round     Smooth Smooth White/yellow
            7       8 mm        irregular    lobate contoured White/yellow


        1                        2
                1


    7                       3

6                                4

                                             5

                    5
     Results: Washed Hand


1.


     2.

            Size   Shape         Margin     Surface   Color
          #
          1 4 mm   Irregular     lobate      Smooth   yellow
          2 1 mm   filamentous   filamentous smooth   white
         Results: Unwashed Hand

  Size    Shape       Margin   Surface Color
#
1 2 mm    Irregular   lobate   smooth   yellow
2 2 mm    round       Smooth   smooth   yellow
3 1 mm    round       Smooth   Smooth   white
                                                     1
                                                 2       3
                               Results: Keyboard
          Size            Shape                  Margin     Surface   Color
    #
    1 4 mm Irregular                             lobate      Smooth   yellow
    2 1 mm filamentous                           filamentous smooth   white
 # Size   Shape       Margin   Surface Color
1 2 mm    Irregular   lobate   wrinkled yellow
2 1 mm    round       smooth   smooth greenish

                                                                      2.


                                                             1.
                     Control
   An unopened agar
    nutrient plate, which
    ruled out agar
    contamination, had no
    bacteria species
    present.
   Species vs. Environments

         Number of Bacterial Species on Agar Plate


            8

            6

# of Species 4

            2

            0
                 Air Keyb Unw Was Pond Chic Soil
       Series1   7    2    2   3    3    4    3
                          Environments
       Conclusions/Observations
   The results supported our hypothesis since
    bacteria grew in all of our samples.
   The results did not support our hypothesis
    concerning the hand washed with anti-bacterial
    soap since it did not house less species than the
    other environments tested.
   We were surprised to learn that the air not only
    housed the most bacteria, but housed the most
    bacterial diversity of species as well.
        Further Investigations…
   Further studies can be conducted by using TEM
    microscopy, SEM microscopy, and gram staining,
    to specifically identify what type of bacterial
    species were present in each environment.
   Research can also be conducted to figure out as to
    why the unwashed hand contained more bacteria
    than the washed hand.
   Further research can be done to determine if any
    of the bacteria found in our samples are harmful to
    humans.
       Questions to Ponder…
 Do all bacteria grow at the same rate, and
  what factors in the environment contribute
  to determining their “carrying capacity?”
 What research can be done to determine
  whether bacterial species and fungus
  compete with each other for nutrients and
  space in selected environments?
References
  Coccoid-shaped Bacterium (causes skin infections), Enterococcus faecium
(SEM x33,370). This image is copyright Dennis Kunkel at
www.davidkunkel.com, used with permission.
 Morgan, I.G. and Brown Carter, M. E., Investigating Biology: A
Laboratory Manual for Biology. California: Benjamin/Cummings Publishing
Co., Inc. 1993.
 Rod-Shaped Bacterium, hemorrhagic E. coli, strain 0157:H7 (division)
(SEM x22,810). This image is copyright Dennis Kunkel at
www.davidkunkel.com, used with permission.
 Spirilla- shaped Bacterium (SEM x33,370). This image is copyright Dennis
Kunkel at www.davidkunkel.com , used with permission.
         Serratia marcescens




Gram stain       Negative.
Motility         Motile.
Habitat          Occurs naturally in soil and water as well as the
                 intestine.
Pathogenicity:   Associated with urinary and respiratory tract infections,
                 endocarditis, wound infections, and eye infections.
Gram-positive and gram-negative bacteria
             Difference Between Gram-Negative
             and Gram-Positive Bacteria


Gram-Negative Bacteria                 Gram-Positive Bacteria


More complex cell wall.                Simple cell wall.


Thin peptidoglycan celll wall layer.   Thick peptidoglycan celll wall layer.


Outer lipopolysaccharide wall layer.   No outer lipopolysaccharide wall layer.


Retain safranin.                       Retain crystal violet/iodine.


Appear pink/red.                       Appear blue/purple.
Antibiotic Sensitivity Test
  Antibiotic Sensitivity Test




                          P10
        TE30


       Ø10




E15                               C30




        Ø14                Ø20



 K30
                                 NA30

               Ø14   Ø8




         S10              NB30
Hypothesis:
Kanamycin is one of the most sensitive
antibiotics because infections treated
include respiratory tract, urinary tract, skin,
soft- tissue and abdominal infections.
Prediction:
The size of the zone of inhibition is the
largest.
Results:
The size of the zone of inhibition is the 2nd
largest
                 Antibiotic Resistance




•   Some bacteria have developed resistance to antibiotics naturally.
•   Bacteria can become resistant to drugs in a number of ways.
         - Mutation.
         - Exchange genes with other bacteria.
         - Resistant traits spread to future generations quickly because
              of rapid reproducing.
    Mechanism
    Antibiotics kill or stop the growth of harmful bacteria.



    Limitations
   Reason unknown why S. marcescens is sensitive to certain
    medications.
   Further research needed.


Future Work
   Develop new drugs to confront bacteria resistance.

				
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