Microbial Monsters Part III : Misunderstood Green Monsters and Dracula! (Chloroplast & Micavibrio)
Updated: Nov 21, 2020
Leaving the forest of our fears behind we enter into the third segment of our macabre microbial monsters we are going quite classic once more (click here for all our Halloween articles). Today we will talk about our favorite green microbe and favorite green monster chloroplast and Frankenstein. As well as another blood sucking vampire segment, but this time the microbe is the vampire not just vectored by one.
Who Was Frankenstein?
Frankenstein’s monster has been a part of horror folklore for over 200 years and is the brainchild of a 19th century woman, Mary Shelley. Frankenstein was actually her submission to a friendly horror story competition between herself, her husband, and the great Lord Byron. She was 18 at the time and clearly won the competition.
The book has been transformed into many movie adaptations that have invigorated and intrigued the cinematic world for decades. The story revolves around a dedicated and passionate scientist who attempts to make life in a rather unorthodox way. Upon his success, he's horrified by his creation and decides the monster needs to be destroyed. To many, Frankenstein’s monster is just that, a monster and a failed experiment.
But it’s also a depiction of human society and our hatred for ugly and grotesque things. Humanity is always trying to create life, but it is never perfect. No matter what we create whether it's a thought, a human or another being, everyone needs to be loved and feel supported. Frankenstein’s monster was never given this, the moment he became conscious on this earth he was treated with disdain and hatred. He was even hated by his father, Dr. Frankenstein, who is the true monster in all of this. Victor Frankenstein never even gave his son a name before casting him out to the cruel unforgiving world.
So while most say Frankenstein and refer to his monster as the evil doer, we should continue referring to Frankenstein but point to the shameful and neglectful scientist.
How Does Chloroplast Fit Into All This?
At any rate, the idea of mashing together old parts and assembling them into new life has roots in ancient biology and probably in future biology as well. Today, we pair the giant, powerful, green monster of Frankenstein with the tiny green organelles of chloroplast and the powerhouse of the cell mitochondria.
But chloroplast and mitochondria are organelles in plants and animals, they aren’t microbes, so what are they doing here? This is true, but they were once microbes that live free in the world.
A billion years ago there was an eukaryotic cell (has nucleus) and prokaryotic cell (no nucleus). The eukaryotic cell was hungry and decided to eat the cyanobacterial cell whole. The cyanobacteria was still fully intact and decided to chill in its new home, photosynthesizing, and the eukaryotic cell was like well that’s pretty sweet now I don’t have to find food.
And from then on they went on like that; naturally, any relationship that lasts that long will inevitably end up in a fair bit of codependency. The bacterial cell would shed some genes, no longer needing to lug around the extra machinery, and the eukaryotic cell continued to grow, diversify and eventually speciate. Now, chloroplast only has around 120 genes as part of its genome and relies entirely on the host to provide everything that it can’t.
A similar thing happened to mitochondria. It was once a strong independent microbe but than one day it got gobbled up and was content joining forces with the larger cell for mutual survival.
Because of chloroplast, plants can photosynthesize and because of mitochondria, we all have energy! While plants have both chloroplast and mitochondria in their cells, animals only have mitochondria. Interestingly, some animals such as the Sacoglossan sea slugs have both chloroplast and mitochondria! But these little powerhouses of the cells, as they are sometimes called, weren’t always there.
It is believed that both mitochondria and chloroplasts were once free living microbes that were engulfed by a cell. Instead of degrading the engulfed cell, they learned to live with each other and live in perfect harmony. Alternatively I suppose you can say the prokaryotic cell enslaved the other, dooming chloroplast and mitochondria for centuries of hard labor! (*Insert evil laugh here*)
Micavibrio spp. - The Dracula of the Unseen World
We’ve already published a vampire blog, but microbes and vampires just have so much in common, so here’s a little different take on vampires in the microbial world….
Organisms that belong to the group of parasites are some of the most disturbing yet fascinating creatures. Like vampires, they feed off of the living for their own survival, sometimes by literally sucking the life from their prey. This same behavior exists at the microbial scale with a Micavibrio spp.
The Vampire Mechanism of Micavibrio
These microbes search for their victims and grip the cell, leaching nutrients from its prey, feeding off the life source for their own survival, just like a vampire. Lucky for us, their ideal meal is not mammals but microbes. Many of their favorite dishes are microbes that are harmful to mammals (aka pathogens). Interestingly, it is unable to replicate without a host, the death of another is the only way for it to survive. Despite this highly dependent nature, Micavibrio spp. actually has all the genes it needs to function metabolically.
Vampires as Living Antibiotics?
Given their specificity and affinity to some human pathogens, they may be a great targeted alternative to broad spectrum antibiotics (which kill the good along with the bad), therapy that would be deemed a “live antibiotic.”
In fact, one study saw a ~100 fold reduction in biofilm cell viability when Micavibrio aeruginosavorus was mixed with pathogen P. aeruginosa. Biofilms are a sticky protective coating that microbes can produce to protect themselves. These biofilms can enhance the microbes protection from antimicrobial by up to 1,000%. So the ability to not only prey on P. aeruginosa but also to disrupt its protective shield makes this sneaky vampire microbe a very viable option to control this pathogen.
The ability to prey on a pathogen is not enough to be used in medicine. An enemy of my enemy is only a friend if they are also not an enemy to you. However, there is no evidence that the Micavibrio spp. are harmful to humans.
In another study, which used a mouse model, showed introducing the vampire into the mouse did not produce any negative effects. Furthermore, the mouse immune system was not triggered and was able to flush out the microbe from its systems. This means that micavibrio spp. is potentially safe to use as therapeutic as they are non-toxic to mammals, an enemy to our enemy and do not linger or out stay their welcome in the body.
Unfortunately, because of their epibiotic (living on an organism parasitically) they can be hard to research as they are so dependent on the host for survival. Regardless, what an interesting solution to a pathogen problem.
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