It's an interesting question. Yes, Bacillus subtilis is used to create a good variety of sensors. Naturally, with the help of genetic engineering. Some reasons: it's a harmless bacterium, it grows easily and its metabolism is well known. Here are a few examples: www.nature.com/articles/s41467-023-37582-x journals.asm.org/doi/10.1128/spectrum.00432-23 onlinelibrary.wiley.com/doi/10.1002/cjoc.201300487 :-)

@BernardJenni really interesting I like the h202 sensor. I wonder what kind of electrodes they used, gold maybe ? I see them mention how silver ion isn't encompassed by glucose and acid, not sure if it would be the case against our door particles like proteins and what not. It doesn't really tell me how the sensor work though, using silver particle I can only speculate. Using a magnetic sensor they can manually charge the agnp ( silver particles) which would deliver a charge thru the leectrod previously installed on the agnp . And the shock's current is what they would observe to find the amount of h202 in the solution . It's an interesting field, I don't think it's what I was looking for though sadly

Thanks for your visit and comment :-)

www.shimadzu.ch/products/maldi/ms/axima-confidence/index.html

Dear Jerry, Thank you for your kind comment. I am retired and work in my homelab. This gives me total freedom to study only what is of interest. Next week I'll be posting a video about a mold that I shot last year. The Mayorella video is from footage taken in 2019. I still have plenty to work with from my archives, and am busy now with chlorophyceae, but I can't predict what fascinating things I'll observe under the microscope tomorrow.

Thank you for your interest. Your channel contains lots of interesting videos. My video ‘Set-up for the galvanotaxis experiments with protozoa’ in the same playlist contains most of the answers to your questions. I think an important aspect of the problem is the concentration of ions in the water. In our calcareous region, the water contains a lot of Ca++ ions. Water from granite regions will be much softer, which will considerably change the electrical parameters (resistance, mA, etc...). I think that protozoa follow the flow of ions, which must be present in fairly high concentrations.

@@BernardJenni Thank you very much for your reply. It was my pleasure. Do you mean that the displacement is due to the need for cations such as Ca++? I would be interested in clarifying whether it was 0.1 mA, 0.1 A or 0.01 A. Regards.

According to my notes, I measured 0.09 mA for 50V, 0.13 mA for 75V and 0.18 mA for 100V. Tetrahymena begins to move at 0.01 mA minimum. It would be interesting to repeat these experiments with water containing ions other than Ca++.

@@BernardJenni Thank you very much

Thanks!

Thank you for your interest! Bacillus subtilis is not a pathogenic bacterium, but its characteristics depend on the strain that is used. Japanese natto is made exclusively from the B. subtilis var. natto strains. These have been extensively studied and are also used as probiotics because they provide numerous vitamins and other beneficial substances. The strains of B. subtilis used to treat concrete are not often mentioned in publications. They are often isolated from the environment and selected to obtain the required properties. Bacillus subtilis inhabits the rhizosphere and secretes anti-fungal metabolites that protect plants from infections. Certain strains of B. subtilis are therefore also used as biocontrol agents.

@@BernardJenni thank you!

Thanks for your kind comment :-)

Thanks for your comment. Initially, I thought of Cylindrotheca closterium but the frustule corresponds more to Nitzschia sp. We'll have to investigate further...

@@BernardJenni Strange creatures! Following up on Dr. Kryvenda's comment, a search in Google Scholar turned up lots of references to "flexible rostra" in both Cylindrotheca fusiformis and C. closterium. Apparently, the rostra contain adhesives enabling the diatom to attach to a substrate, such as a copepod. Amazing to see them wriggling around like this. 😃

Hi Bruce! Thanks for your comment. I found most of these publications. If you grab inside, you'll see that the info concerning our issue is meager.

A research microscope Leica DMRB, mostly with interference contrast for protists. Thanks for your visit!

Good luck! ;-)

It seems to be fairly common, but this is the first time I've seen it. If the sampling site corresponds to its favorite biotope (e.g., anoxic surface sediments with decaying plants in freshwater ponds), it should be possible to find it.

@@BernardJenni Thank you very much!

Thanks Carlos !

Shooting probably with the 20x objective, not the 100x.

Thanks !

:-)