A special bacteria and an important thing.

A few days ago I saw a special kind of bacteria called magnetotactic bacteria in the internet. Its a special polyphyletic group of bacteria that orient themselves along the earth’s magnetic field lines. So they can only move north or south in a one dimensional motion. They do this for staying in the zone where there is perfect concentration of oxygen in the pool or water body. They make small crystals of magnetite or gergite in their small organells called magnetosome. They align these crystals to become a mini magnetic compass which can move only north or south. But you can change the direction by taking a magnet near to them. See the video.

Here’s how to extract them:

You can control their motion while viewing them under a microscope too. But folscope has two magnets near the place of slide. So the bacteria might just move up and down only which might be a problem to see them. How to solve this problem? Give your ideas in the comments please.

An important thing:

Is 108935-02-AK in my post ‘Old observations‘ a Naegleria fowleri (the brain eating amoeba) or indicate it’s presence? Please check it. Because the water was collected from a pond of saintmartin’s island where many people live and many go to visit every year. I am embedding the video here for you:



7 Comments Add yours

  1. Akib says:

    Will anyone make any comment here?
    I am hopeless (Especially about 108935-02-AK).

  2. laksiyer says:

    Hi @Akib. To say it is Naegleria fowleri would be stepping too far. Based on the fact that it is unipodal (only one foot) and amoebal, it generally falls in the Vahlkamfiidae family. I guess I might have been better calling it Naegleria-like as Naegleria belongs to this family. However, in order to distinguish different genera, you need to look at more details such as
    1. Presence of mitochondria (absence –Lyromonas)
    2. Flagellate stage with one nucelus (Vahlkampfia).
    3. Beak like rostrum– Paratetramitus
    4. If cytosome– Heramoeba
    5. If cysts have pores– Naegleria.. Given this you need to establish pure culture and see how they encyst.
    4. Flagellate stage with 3 flagella- Trimastigamoeba and so on

    1. Akib says:

      Thanks for the reply and information. But does it indicate that the pool might contain naegleria floweri? What should I say to the people who live there? Should I forbid them to use water of that pool? The pool is actually not a swimming pool and it is not in a usable condition during winter. But people might use it’s water in rainy season and summer. You might know that I am too busy to observe it futher. I am scared about it’s contamination in the water tanks and pipes (if it is in there). It was found in the soil near the surface of the pond. I am trying to culture it by kepping the water sample in a small bottle (with soil in it). I can’t observe it but can do a little experiment with it. I can put the water on a small piece of cow/goat brain and see what happens (although it can’t prove it’s presence). Should I do it? Please check the recent comments as they may conatin reply to your comments or something important.

  3. laksiyer says:

    @Akib. Love the detailed instructions on isolating magnetotactic bacteria. You are right, the magnetic field is perpendicular to the slide view. How might we be able to clearly see this? What if you introduce a small magnetized iron pin in the slide? Magnetizing an iron pin is quite trivial by the well known rubbing magnet trick, or perhaps you have access to small magnets. NOw if you place the pin under a coverslip with the bacteria, will the bacteria concentrate on one side of the pin? Dunno need to try it.

    1. laksiyer says:

      Hi @Akib. I wouldnt worry too much. Every recreational water body that is not a swimming pool will have Naegleria and friends. Also it is a very low incidence disease (34 infections in 10 years in the US) and human pathogenesis is not in its regular cycle. Naegleria alarms are never raised by scanning primary water bodies. Water bodies are only designated as to be avoided if someone falls sick with Naegleria after swimming in it. Naegleria fowleri testing requires a lot more rigor and post pathogenesis is done by a spinal tap. However, we might be able to come up with a protocol. To a bacterial culture add your water sample and grow it up above 42C. IF you still see these amoebae, you will raise some interest about its identification and you can pursue it.

      1. Akib says:

        Thanks again. I don’t have any agar for bacterial culture now. But I’ll try it soon. Please check the recent comments again as your comment on the magbetotactic bacteria have opened my mind
        I have 4 new ideas on it . I will make a comment on these (or edit the post). So please check the recent comments and try to inform @Manu because I think he missed this post.

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