This was a productive week! I finished extracting DNA from all of the 4126 collection strain organisms that we did not have 16S for on Wednesday morning as part of my BIOL 3999 activities. Monday afternoon we set up for carbohydrate utilization tests on basal media plates containing 17 (correct me if I’m wrong I forgot to write them all in my book) varying types of carbohydrates. The media contained no carbon source yet 1% NaCl was added due to the fact that all the strains grew well when tested at this salt concentration. 2.5g of yeast extract/L along with 1g of CaCO3, a buffer that soaks up acid produced, made up the rest of the media. We spotted 10 µl of a liquid suspension of our strains that had been rinsed in saline to get off any residue from its previous media that could possible aid in its growth. We also streaked our strains that grew at 10°C onto plates of their optimal media to be incubated at 4°C in the cold room. 22 out of 26 of our strains grew at 10°C so I am excited to see which, if any, can grow at 4°C. Wednesday we extracted DNA from our soil samples using the Ultra Clean Mega Soil DNA Kit. It was fun and I found it easier than the regular small bead beating kit but maybe because it wasn’t so many small tubes. We also observed our pH plates. We had a couple of strains that had some interesting results. For strain 7 we observed a lighter pink band around the outside with a darker center beginning at pH 6 but then at pH 9 is suddenly appeared cream then it was right back to pink at pH 10. Strain 8 was also dark in the center but had a light, almost white, band around the edge at pH 6 and 7 but lost it and the entire colony appeared light pink. Strain 16 was our only strain that displayed strong growth at all pH levels tested. Strain 24 grew the best at pH 4 then had no growth at pH 5 then moderate growth from pH 6- pH 10. I am not sure what happened at pH 5 but we might need to test it again. Overall our strains did not grow well at pH 4 or 5. Only 4 grew at pH 4 and 3 at pH 5. pH’s 6- 10 had growth for all the strains. Below you can see our pH plates for strains 1,2,4,5 and 7. None of these grew at pH 4 and 5 and all grew from 6-10. Strain 7, mentioned above, can be seen in this picture. The best part about the week was our party Wednesday… we should do that more often!!
pH 4
pH 5
pH 6
pH 7
pH 8
pH 9
pH 10 
Carbon Sources:
ReplyDelete1. Control C
2. Arabinose AR
3. Dulictol DL
4. Galactose GA
5. Glucose GU
6. Glycerol GY
7. Inositol IN
8. Lactose LA
9. Mannitol MN
10. Melezitose MZ
11. Melibiose MB
12. Raffinose RF
13. Rhannose RH
14. Ribose RI
15. Sucrose SU
16. Xylose XY
17. Xylan XN
wow you guys had a lot of strains that grew at 10 degrees...seems like everyone did but us...LARRY!!!! LOL j/jk
ReplyDeletemost of the organisms that we are working with usually grow around pH 7 or so. that's probably why many of your strains did not grow at pH's 4-5.
ReplyDeleteyeah we did have a lot that grew at 10 C but i am doubtful about them growing at 4 C.... doesn't one of the groups have some strains that are from Antarctica? I would think those would have the best chance at growing in the cold room.
ReplyDeleteand thanks for the carbon list lroach!!
are the Antarctica strains the ones that start with AT03 or AT04?
ReplyDeleteI think those are Aticama
ReplyDeleteI'm really interested in these color changes at the various pHs. I hope that we can talk about it in class. I really don't think that we had contamination on 69 if other people are observing similar color changes and rings around their colonies!
ReplyDeleteAT is Atacama
ReplyDeletePO strains came from the glacier on Pico de Orizaba in Mexico