Dear Drishya, have you tried selenium or tellurium as a substitute for sulphur? Just a thought since both on the same periodic column, and selenium in particular since its is half way a metalloid between sulphur and tellurium. Some bacteria use selenium extensively, be interesting to know if the machinery is similar to SOB

Thank you for the suggestion, Bernhard. No, I haven't looked at using selenium and tellurium but its definitely worth investigating.

I am planing to culture the GSB as well. The medium prepariaton is quite complicate. Do you have any better option? Is the medium very sensitive to oxygen?

Thank you.

Ps. I'm going to use Pfennig’s Medium

https://www.atcc.org/~/media/20E12721C7754920806B756A3E444FC4.ashx

Hi Natthaporn, thank you for the link . Yes, the preparation of the media does seem to be quite complicated and the GSB are sensitive to oxygen as well. The media I'm preparing is based on the below links. Hope it helps.

Dear Drishya,

Greetings!

I am using following culture media for green sulfur bacteria and thiosulfate as a substrate.

One liter of liquid medium for C. tepidum (CL) was made of

20 ml of salts A

(0.64 g of Na2 · EDTA · 2H2O, 10 g of MgSO4 · 7H2O, 2.5 g of CaCl2 · 2H2O, and 20 g of NaCl per liter),

20 ml of salts B

(25 g of NH4CH3COO, 20 g of NH4Cl, and 115 g of Na2S2O3· 5H2O per liter),

20 ml of buffers (25 g of KH2PO4 and 105 g of MOPS [3-{N-morpholino}propanesulfonic acid] per liter),

1 ml of trace elements,

50 μl of 10-mg ml−1 resazurin, and 20 μl of 1-mg ml−1 vitamin B12.

After the medium was autoclaved at 121°C for 20 min, a freshly made, filter-sterilized solution of 2.0 g NaHCO3 in 50 ml of water was added. The pH of the medium was usually within the desired range of 6.9 to 7.0 without further treatment but otherwise was aseptically adjusted with 1 M NaOH or 1 M HCl.

And I have attached Green sulfur bacteria (Grown in Sulfide and thiosulfate) picture

And the find the attachment for more information.

Thank you!

Dear Velraj,

Thank you for the detailed recipe. Just a few questions.

1.Where did you isolate your bacteria from? Was it a soil sample?

2. How long did it take to see a significant growth?

3. Did you use an LED light source for the growth?

4. How often did you change the media?

Thank you.

Dear Drishya,

Sorry for the late reply, Here is the answers.

1. I have used pure culture of Chlorobium tepidum; and also I have isolated from activated sludge from domestic waste water treatment plant. We can isolate from soil, for that we have to make winogradsky column for isolation of GSB.

2. Within 3-4 days u can see significant growth.(8.5mM sulfide)

3. I have used Incubator with LED light source.

4. Every 4 days.

Best

Velraj

Dear Drishya,

As for the genetics in thiosulfate only oxidation in the GSB Chlorobium tepidium: competent soxB gene (CT1021) is essential for thiosulfate oxidation completely to sulfate without sulphides present. This gene is also responsible for sulfide oxidation. Cytochrome c-554 increases the rate of electron transfer from thiosulfate, but is not essential. See "Sulfur oxidation in mutants of the photosynthetic green sulfur bacterium Chlorobium tepidum devoid of cytochrome c-554 and SoxB." Photosynth Res. 2009 May;100(2):57-65. doi: 10.1007/s11120-009-9426-2. Epub 2009 May 7.