20 JULY 2022

What is a strain?

We had all heard the word “strain” before, whether in the context of a relentless pandemic (no fingers pointed!) or while watching a zombie apocalypse movie. This term has many meanings, and even in the same field of application, it can be loosely defined. In microbiology, a strain can be a genetic variation so small between two microorganisms that they are still considered the same species. In other words, a bacterium or yeast can only belong to the same strain if their whole genetic sequence is identical – that is, if they are clones. Any small detectable change will turn them into different strains. This concept, an artificial construct, is of great use in research and industry.

Why do we need a particular strain?

Imagine you want to buy (or adopt!) a dog. Responsible owners wish to research as much before committing to a pet. Thus, you will not only concern yourself with which breed is the most aesthetically pleasing. You must consider which size, temperament, and intelligence suit you best. You must also observe a thousand million details like how much hair they shed, how loudly they bark, and how much time outside they need. Last, it would be best if you watched out for unique quirks and even abilities. Some dogs are good support for the differently abled, some are great guardians, and some are excellent at drooling all over your carpet. They are all dogs, but the possibilities are endless.

Just as every prospective dog owner has a perfect canine friend, every research and field application potentially has an excellent match to suit its needs. An example would be the different E. coli strains in laboratories all around the world. Some of them cause illnesses, some are harmless and excellent subjects to conduct studies, and some even produce life-saving insulin. No wonder finding the perfect strain is such a big deal.

How do we find it?

Unlike the lucky dog owners, scientists cannot exactly go to a shelter or pet store to find their new best friend. Their only option is to isolate the microorganism from samples in the wild. But, much like adopting a stray dog, it is a toss of the dice and will probably not suit their exact needs. So instead of shopping around, researchers have to get a little adventurous: they must create their perfect strain. 

There are a few ways to go on about this. One of them, genetic engineering, consists of isolating a characteristic present in another organism and introducing it to the target microbe. This technique produces Genetically Modified Organisms. Yes, the (in)famous GMOs. While genetic engineering technology continues advancing, it has caught a lot of flack from the scientific community and the public, as these mutations are “unnatural” and would never occur in the wild. In addition, there exists concern over how GMOs could displace natural organisms and create ecological catastrophes. 

A different but still helpful strategy is to expose natural organisms to mutagens. These can be chemicals, radiation, or even UV light. These stimuli are harmful to microbes. However, what doesn’t kill you makes you stronger, and in this case, the survivors are left with random natural mutations. It is up to the researcher to sift through them to find the best fit. Organisms created by this technique are not considered GMOs by legislation, and since their mutations are natural (just sped-up), fewer objections exist against them.

How do we keep it?

Once we have found our match, we need to ensure it is available for our purposes for a long time. Thankfully, microbes reproduce fast and effortlessly, taking mere minutes or hours to create new spawns. The bad news is that microscopic organisms subscribe to the “live hard, die fast” ideology. As quickly as they reproduce, they can be notoriously short-lived – some perish within a few hours of being exposed to the air on a surface without nutrients. Paradoxically, if the conditions are right, these microbes can live much longer than you, me, and every employee at Mycorena combined. Usually, this involves very low temperatures (way below freezing), making the microbes dormant. However, after some slow thawing and adding nutrients, they will return to business. I wish my morning coffee woke me up that quick!



Zelfa Hotema, M.Sc

R&D Intern






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