Tag Archives: bacterial counts

Vibrio challenge CONTINUED (from yesterday)

Significantly more bacteria in the container containing autoclaved oysters. Collected 2 x 50mL from each treatment. Collected ~750mL from each treatment. Cells were pelleted 4000RPM, 15mins, 4C. Supe was removed and pellets frozen @ -80C.

100uL of a 1:1,000,000 dilution of the control bacteria were plated on 1x LB + 1% NaCl plates and incubated O/N @ RT. 100uL of a 1:10,000,000 dilution of the exposed bacteria were plated on 1x LB + 1% NaCl plates and incubated O/N @ RT. Control colony count the next day = 563 colony forming units (CFU). Exposed colony count the next day = 367 CFU.

Control Calculations
563 CFU/100uL = 5.63 CFU/uL
5.63 CFU/uL x 1:1,000,000 dilution = 5.63 x 10^6 CFU/uL
5.63 x 10^6 CFU/uL x 1000uL/mL = 5.63 x 10^9 CFU/mL

Exposed Calculations
367 CFU/100uL = 3.67 CFU/uL
3.67 CFU/uL x 1:10,000,000 dilution = 3.67 x 10^7 CFU/uL
3.67 x 10^7 CFU/uL x 1000uL/mL = 3.67 x 10^10 CFU/mL

Share

Vibrio challenge CONTINUED (from yesterday)

500mL culture was split evenly between two containers containing 3L sterile sea water each. One container also contained 3 large, autoclaved C. gigas. Containers had an air stone to promote circulation. 4 x 1mL samples were collected from each container, pelleted @ 10,00RPM 1min. Supe removed and samples stored @ -80C. Samples will be collected @ t = 0, 0.5, 1.0 and 24 hrs. Containers were covered with aluminum foil to minimize splashing caused the by the air stone.

100uL of a 1:1,000,000 were plated on 1x LB + 1% NaCl plates and incubated O/N @ 37C. Colony count the next day = 399 colony forming units (CFU).

399 CFU/100uL = 3.99 CFU/uL
3.99 CFU/uL X 1:1,000,000 dilution = 3.99 x 10^6 CFU/uL
3.99 x 10^6 CFU/uL x 1000uL/mL = 3.99 x 10^9 CFU/mL
3.99 x 10^9 CFU/mL x 250 mL/container = 9.975 x 10^11 CFU/container

Share