Hi dear Earthlings ! Here is my first biology report. In the main part of this microbiology project, I will try to detect and characterize bacteria from desert's soil samples. In this aim, I will use various observations, colorations, biochemical tests and growth on selective media. Further investigations will be made when back on Earth to confirm the bacteria's identity. Among them, probably PCR and sequencing, or mass spectroscopy (not confirmed yet).
(04/12/2015)
First thing I did yesterday was a complete inventory of the lab equipment, with the help of the inventory kindly sent by Dr. Jean Hunter. Most of the biology supplies were present, but some were not found or broken. Here is a short list of the modifications :
- no 200 ml graduated cylinder
- only one 10 ml graduated cylinder
- only 1L of distilled water
- only 11 erlenmeyers (500ml)
- only 4 beakers (1000ml), 4 beakers (500ml), 5 beakers (250ml), 1 beaker (100ml)
- 2 pairs of heat gloves
- field vest with pockets and flagging not found
- vortex MS1 Minishaker not working
- labcoat not found
- scissors not found
- only 4 graduated bottles (500ml)
- didn't found 10 powder spoons
- tube holders and falcons not found
- hot plate not found (not the one with the stirrer)
The most annoying thing for my experiment is the vortex MS1 Minishaker, which is probably broken. It seems old, this is maybe the reason why it is not working anymore. It shouldn't be a serious problem for my project (I can homogenize my eppendorfs without a vortex), but it could be interesting to buy a new one for next season.
In the afternoon, I tidied up the laboratory. In my project, I will have to use the following material : microscopes, centrifuge (minifuge), stirrer, balance, incubator, fridge. I also brought all the following equipment :
- petri dishes (360)
- surface thermometer
- falcons
- eppendorfs
- inoculation loop
- micropipettes (P20, P200, P1000) and tips
- petrifilms
- immersion oil
- parafilm
- 0,45µm filters
- bunsen + gas (sterile zone)
- gram staining (iodin, decolorizer, safranin, crystal violet)
- LB medium (200g)
- simmons citrate medium (17g)
- Mc Conkey medium (38g)
- King A medium (33g)
- DNA medium (32g)
- thiolglycolate (23g)
- starch (4g)
- milk medium (30g)
- PBS
- yeast extract (20g)
- NaCl (40g)
- tryptone (20g)
- agar (40g)
- hydrogen peroxyde (catalase tests)
- oxydase tests
(04/13/2015)
Today, I tried the new protocol of sterilization with the pressure cooker. I prepared 1L of LB-agar medium, with some eppendorfs and toothpicks. The LB Petri dishes will be used to grow bacteria coming from samples of the EVA planned for tomorrow. The LB medium is not selective, so I will first try to dilute the samples to obtain pure cultures (single colony on the surface). The dilution will go from 1 to 10-5. The day after tomorrow, I will begin the identification protocol (observation, gram staining, catalase/oxydase tests, growth on selective media).
The sterilization in the pressure cooker was succesful, since all the sterilization strips became black. I then runned the LB-agar in Petri dishes. One liter allowed me to obtain 48 Petri dishes. I let them cool down, and then put them in the fridge over night.
I also too part in the EVA of the afternoon with Bastien. I found some interesting spots to collect samples in the next days. I also would like to go to the old river bed situated at the followings coordinates: 125-0518150-4253750. I plan to collect 5 samples in various soils and various places. I will then begin the biochemical characterization. Any suggestion will be welcome !