Combined Effect of Ferric Chloride and Mercuric Chloride on the Growth of Cyanobacteria Anacystis nidulans

1
Combined Effect of Ferric Chloride and Mercuric
Chloride on the Growth of Cyanobacteria Anacystis
nidulans

• By Ted Handler, Farrell Parker, Alex Lewis, and
  Nick Reed

2
Dr. Lee H. Lee
3
Background Information

• Industry spills massive amounts of heavy metals
  such as mercury, selenium, ferric chloride, and
  mercuric chloride in our water supply. This study
  tests the effects of ferric and mercuric chloride
  on the growth of Anacystis nidulans as an
  indicator of life in our waters.

4
Anacystis nidulans

• Small
• Sensitive
• Photosynthetic
• Simple
• Provide an indication of heavy metal pollution on
  metabolic activities of higher organisms in the
  ecosystem.

5
Toxicity of Mercury

• Mercury in any form is toxic.
• Toxic effects can result from vapor inhalation,
  ingestion, injection, or absorption through the
  skin.
• Hg accumulates mostly in the kidney, causing
  significant renal damage.
• Chronic exposure leads to accumulation within the
  brain, causing neurological symptoms and birth
  defects.

6
Iron as anEssential Micronutrient

• Mineral needed in small amounts for body to stay
  healthy.
• Found in meat, fish, and poultry.
• Functions in the transport and storage of oxygen.
• Involved in DNA synthesis and catecholamine
  metabolism.

7
Toxicity of Iron

• Toxicity most common in children.
• Toxicity occurs when free iron levels exceed the
  iron binding capacity of transferrin in blood.
• Free iron damages many organs by direct cellular
  toxicity.

8
Materials

• 4 Flasks
• 4 Cuvettes
• Disposable Pipettes
• 5 mL sterile pipettes
• Cotton
• Cloth (breathable)
• Foil
• Tape
• 3M Medium
• Cadmium and Ferric chloride
• Hand Tally Counters
• Microscope
• Micropipettes

9
Procedure

• We made a 3M medium for cell growth, using
  pipettes and micropipettes, and ten compounds.
• We adjusted the pH to 7.95.
• We sterilized it by autoclaving the medium at
  121 C.
• We mixed the Anacystis nidulans with the medium.
  Then distributed it into 4 flasks. Each flask
  with 100mL of Anacystis nidulans culture.
• 1st flask had no heavy metals, this was our
  control.
• 2nd flask has 0.5 mg/L of HgCl2 and 50 mg/L of
  FeCl3.
• 3rd flask has 1 mg/L of HgCl2 and 50 mg/L of
  FeCl3.
• 4th flask has 5 mg/L of HgCl2 and 50 mg/L of
  FeCl3.

10
Procedure (contd)

• We used a micropipette to transfer HgCl2 and
  FeCl3
• Then we observed the Anacystis nidulans every 3
  or 4 days by two methods.
• First, we used a spectrophotometer to measure
  absorbance levels at 750nm.
• Second, we used hand tally counters to count the
  cells under a microscope, on a special slide
  called a hemacytometer, or a bacterial counting
  chamber.

11
Results Control
12
Results Flask 2
13
Results Flask 3
14
Results Flask 4
15
pH Results
Day Flask 1 Flask 2 Flask 3 Flask 4
Day 1 7.95 7.95 7.95 7.95
Day 27 9 9.4 9.15 7.41
16
Conclusions

• After extensive growth of Anacystis nidulans in
  flasks 2 and 3, a resistance is built to the
  mercuric chloride and ferric chloride. The
  cyanobacteria thrives after growing a resistance
  and grows at a rate faster then that of the
  control. However, after a stationary point is
  reached at a high enough concentration, the
  cyanobacteria begin to die.

17
Conclusions (contd)

• In flask 4, the concentrations of the heavy
  metals were too high for the cyanobacteria to be
  able to resist it. The cyanobacteria had no
  chance to grow, and began to die very rapidly,
  from the beginning of the experiment.

18
Thank You!