Prokaryotes are Complex, Despite What We Learned
We all know prokaryotes are composed of only ribosomes, a plasma membrane, and genetic material (DNA or RNA). Likewise, in either a grade school or college introductory biology class, we’ve all been shown a table comparing prokaryotes and eukaryotes, and let’s just say, the list for the prokaryotes was shorter than the list for the eukaryotes. Despite what we’ve been told in textbooks and lectures, scientists have recently discovered that bacteria hold fascinating compartments which make them complex. Of course bacteria function in complex ways, an example being how they control gene expression with operons. Yet, from a structural point of view, they are one of the simplest types of cells that exist on Earth. So … what are these compartments exactly, and what kind of purpose do they serve? Let’s take a closer look.
Scientists have fathomed the thought of bacterial organelles for years. If we were to take a super-resolution microscope, we would see that bacterial organelles are extremely small: 10,000 times smaller than a pinhead! Within eukaryotic cells, organelles play key roles that allow the cell to function. To name a few, the vacuoles store waste, the mitochondria generates ATP for the cell, the ribosomes enable protein synthesis, and the nucleus directs cell activity. In short, organelles allow eukaryotic cells to carry out complex functions. So, what do the organelles within prokaryotic cells do? They enable them to carry out extraordinary, complex functions!
Professor Trevor Lithgow and Associate Professor Chris Greening, from the Monash Biomedicine Discovery Institute (BDI), have recently placed the spotlight on bacterial organelles. Some of the complex roles these bacteria play involve breaking down toxic compounds and helping bacteria photosynthesize in low lit areas. It has also been seen that it helps bacteria obtain the nutrients they need for cell growth and reproduction by allowing them to utilize gas obtained from the organelles to enable the cell to rise or sink in water. If such organelles give one bacterial cell such complexity, then handling the millions of bacterial cells that surround us becomes much more complex.
Antimicrobial resistance is a growing health issue around the globe. Pathogens such as Methicillin-Resistant Staphylococcus Aureus (MRSA) and Vancomycin-Resistant Enterococcus (VRE) have become serious threats that cause thousands of people to fall ill every year. Associate professor Greening brings up that the pathogen that causes tuberculosis uses fatty molecules from the host to store energy allowing the pathogen to stay within the host’s lungs for years. In addition to inappropriate antibiotic use, such characteristics of pathogens enable antimicrobial resistance to spread around the globe.
Studying these organelles and how they function could be critical to understanding how to combat antimicrobial resistance. Perhaps antibiotics that inhibit some of the essential organelles to function could be created. As of now, a majority of antibiotics target transpeptidase that prevent the cross linkage of peptidoglycan necessary to create the bacterial cell wall. However, bacteria have found there way around this by coming up with proteins such as Penicillin Binding Protein (PBP) 2a which has a low affinity for most beta-lactam antibiotics that target PBPs. Finding alternative methods by which antibiotics can target antimicrobials is something future microbiologists should look into. Prokaryotic organelles is just one route of many.
Resource:
MonashUni. “Monash Scientists Expose Fascinating ‘Compartments’ in Bacteria.” EurekAlert!, eurekalert.org/pub_releases/2020–07/mu-mse072920.php.
