This is really, really interesting... My wife who teaches Classical Studies, and who has no interest at all in microbiology, might develop a bit more respect for your work when I tell her about the Roman baths' sample - - Ha!! (Keep the videos coming! Subscribed.)
How do you isolate the specific bacterium you are looking for from what I imagine must be an enormous variety of bacteria contained in your starting sample (lake sediment, cow manure, etc)? I imagine you first do a rough isolation by growing the bacteria in conditions where your target bacteria will thrive but other bacteria will die out or slow their growth, then streak the surviving bacteria to produce individual colonies. But wouldn't that still have too many non-target species, or what if two different types of methanotrophs coexist in the same sample? I suppose at that point you bring in DNA analysis to make sure that you have a genetically uniform culture consisting of just one species.
Mr Schrödinger - I am the one who games. Isolation is a two part process. First and foremost selective media will be used on a sample. We know that certain environments will be conducive to certain species of bacteria and will limit or inhibit growth of other species. We imitate this in the lab, using media that help one species or group of bacteria grow while limiting or killing others. This is the primary way isolation occurs. We can then streak out, or quadrant streak, the remaining bacteria on plates covered in another selective or the same selective media. This streaking process allows us to identify individual colonies of bacteria and select one to grow based on colony morphologies.
Thanks for the question. The key concepts of the isolation I used have been described below but I will go into a little bit more detail on the methods I used and answer some of your other questions. The isolations first started with taking a small amount of environmental sample and adding it to a larger volume of liquid growth media designed for growth of the target organisms. Methane was added to these samples and this simultaneously dilutes out carbon compounds that support non-methanotrophic bacteria (from the original environmental sample) and promotes the growth of methanotrophic bacteria. After this stage the proportion of methanotrophs to non methanotrophs greatly increases, though as you said, the sample and colonies would be a mixed population of methanotrophs including non-target organisms. I regrew single colonies to isolate out a single bacterium though I used a method called “extinction dilution” where I successively diluted the colony multiple times until no bacteria remain and then grew these dilutions on an agar plate. The dilution just before no bacteria remain contains few or one cell. This dilution is then spread over an agar plate and grown and the single cell forms a colony containing one species. This allows for separation of single cells and therefore single species from the many species present in the original sample. Mixed methanotroph colonies are less likely as they can grow independently in the media very well and so are not hard to separate (unlike non-methanotrophic bacteria). A mixed methanotroph colony, as you said, can be seen by diverse colony morphology or colour and non-genetic uniformity in the DNA sequencing.
These white marks are not representative of the bacterias amounted together, right? If not indeed, where does it come from? A side question: why are these two last vids unlisted?
1:59 "This was isolated from cow manure... Eh, that was a fun sampling" XD
This is really, really interesting... My wife who teaches Classical
Studies, and who has no interest at all in microbiology, might develop a
bit more respect for your work when I tell her about the Roman baths'
sample - - Ha!! (Keep the videos coming! Subscribed.)
Just drooling over the equipment these people have...
I'm fine with that as long as you clean it afterwards.
How do you isolate the specific bacterium you are looking for from what I imagine must be an enormous variety of bacteria contained in your starting sample (lake sediment, cow manure, etc)? I imagine you first do a rough isolation by growing the bacteria in conditions where your target bacteria will thrive but other bacteria will die out or slow their growth, then streak the surviving bacteria to produce individual colonies. But wouldn't that still have too many non-target species, or what if two different types of methanotrophs coexist in the same sample? I suppose at that point you bring in DNA analysis to make sure that you have a genetically uniform culture consisting of just one species.
Mr Schrödinger - I am the one who games. Isolation is a two part process. First and foremost selective media will be used on a sample. We know that certain environments will be conducive to certain species of bacteria and will limit or inhibit growth of other species. We imitate this in the lab, using media that help one species or group of bacteria grow while limiting or killing others. This is the primary way isolation occurs. We can then streak out, or quadrant streak, the remaining bacteria on plates covered in another selective or the same selective media. This streaking process allows us to identify individual colonies of bacteria and select one to grow based on colony morphologies.
Thanks for the question. The key concepts of the isolation I used have been described below but I will go into a little bit more detail on the methods I used and answer some of your other questions.
The isolations first started with taking a small amount of environmental sample and adding it to a larger volume of liquid growth media designed for growth of the target organisms. Methane was added to these samples and this simultaneously dilutes out carbon compounds that support non-methanotrophic bacteria (from the original environmental sample) and promotes the growth of methanotrophic bacteria.
After this stage the proportion of methanotrophs to non methanotrophs greatly increases, though as you said, the sample and colonies would be a mixed population of methanotrophs including non-target organisms. I regrew single colonies to isolate out a single bacterium though I used a method called “extinction dilution” where I successively diluted the colony multiple times until no bacteria remain and then grew these dilutions on an agar plate. The dilution just before no bacteria remain contains few or one cell. This dilution is then spread over an agar plate and grown and the single cell forms a colony containing one species. This allows for separation of single cells and therefore single species from the many species present in the original sample.
Mixed methanotroph colonies are less likely as they can grow independently in the media very well and so are not hard to separate (unlike non-methanotrophic bacteria). A mixed methanotroph colony, as you said, can be seen by diverse colony morphology or colour and non-genetic uniformity in the DNA sequencing.
Is this like a lysteria strain? So by this logic if we ferment cow manure long enough with a balloon it'd produce us methanol or better
These white marks are not representative of the bacterias amounted together, right? If not indeed, where does it come from?
A side question: why are these two last vids unlisted?
They probably batch uploaded all the parts and are releasing them one at a time. Also, how'd you find it if it was unlisted?
Rafael Marques Which white marks?
The white marks in the petri dishes? I think those are from the tip of the tool they used to spread the bacteria in each quadrant of the dish.
I used the playlist in which they appeared. There's also the fifth there, which is pretty interesting as well.
Thanks, do you know if this is common pratice in order to select apart which region you have bacteria in?
'Meee' - Thane. 🤣 You Brits are so funny.
Now drop them on venus.