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Coliphages as Fecal Pollution Indicators of
the Guavate River Basin, Puerto Rico
LEYDA VILLAGRASA
JOHN L. RIVERA MELENDEZ
Introduction What are coliphages?
•Phages that infect E.coli
Where are coliphages found?
•Anywhere E.coli thrives
What is E. coli?
•Bacteria found in warm blooded animal feces
Why are Coliphages important?
Used as E.coli indicator. E.coli is used to evaluate Salmonella in fresh water systems.
3.4 million people die from fresh water pollution due to Salmonella. Used to indicate how contaminated a fresh water system is. 780 million people don’t have access to uncontaminated and drinkable water. Drinking contaminated fresh water can lead to many symptoms, one being diarrhea which is the second leading cause of death among children around the world.
Related Investigations
1) Visible light has a negative effect in the number of E.coli
2) Survival of E.coli is prolonged if water is 25 C or more and survival is )decreased if temperature is 5 C or less. (Wislo, 2000) )
Problem
Will different areas of the Guavate river with factors, such as light, fast flow and stagnant(no flow),affect the amount of coliphages?
Hypothesis The different factors of each area will affect the quantity of coliphages.
Purpose of the experiment
Identifying coliphages by taking samples from the Guavate river basin, each sample having a different factor.
By doing this we can know if E.coli is present in the fresh water system and therefore fecal pollution.
Identify the number of plaque forming units of coliphages in the samples per area.
Procedure Before taking samples: Water conditions were verified to see if E. coli could survive in this river.
Area Hour Temperature PH Dissolved oxygen Conductivity Turbidity
Control 9:18 a.m. 20.7°C 7.91 8.4 mg/L 124.7 1.44 NTU
Stagnant water 9:07 a.m. 21°C 6.88 .7 mg/L 129.7 1.60 NTU
High flow 9:26 a.m. 20.8°C 7.87 8.42 mg/L 125 1.99 NTU
High light exposure
9:35 a.m. 21.6°C 7.59 8.06 mg/L 8.06 2.06 NTU
Guavate River basin
Procedure Sample Collection:
Sample 1: Control group
Sample 2: Stagnant water
Sample 3: Fast flow water
Sample 4: High light exposure
Samples on ice at 4°C
http://zyklon1985.blogspot.com/
2007_06_01_archive.html
Lab Procedure:
Aseptic technique
Labeling and dividing plates into groups
Single layer plaque assays
Incubation
Counting of viral plaques
http://www.youtube.com/watch?v=bRadiLXkqoU
Results
Plates divided into groups Control group results Groups 4: High light exposure
ResultsSample PFU’s per sampleSample 1: Control 1.67pfu/50mL
Sample 2: Stagnant water .67pfu/50mLSample 3: Fast flowing water .67pfu/50mL
Sample 4: High light exposure 34.7pfu/50mL
Conclusion
The different factors such as light, fast flowing water and stagnant water can affect the amount of coliphages found.
The area with high light exposure revealed the highest quantity of plaque forming units, there by showing more coliphages.
Future Works 1) Compare with the end of the river that discharges into the ocean.
2) Compare with a river that is in an urban area like San Juan. This way other factors like air contamination or salt can be taken in consideration.
References R. Wcisło, R.J. Chróst, 2000, Survival of Escherichia coli in Freshwater , http://www.google.com.pr/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=2&ved=0CDAQFjAB&url=http%3A%2F%2Fwww.pjoes.com%2Fpdf%2F9.3%2F215-222.pdf&ei=m1h1U_TqO4iqsQTB-4GICw&usg=AFQjCNFnVeh_3r0MA4JzOABehhtTUW2w4w, extracted May 17,2014
Hatfull GF, Cichon P, Foley A, Ford M, Gonda R, Houtz J, Hryckowian A, Kelchner V, Pelluda M, Serra D. et al. 2006,Exploring the Mycobacteriophage Metaproteome: Phage Genomics as an Educational Platform,http://www.plosgenetics.org/article/info%3Adoi%2F10.1371%2Fjournal.pgen.0020092
Science Education Alliance. 2012. SEA-PHAGES Resource Guide. Howard Hughes Medical Institute; Chevy Chase, MA.
Todar K. 2012 , Todar’s Online textbook of bacteriology.http://textbookofbacteriology.net/phage.html , extracted May 1,2014
Acknowledgements
Mrs. Jennifer Paredes Lopez
Dr. Javier Arce
RISE Program