In this post we will know how the prokaryotes are harmful to humans and how they badly impact humans both directly and directly.
So, let’s dive into it…
Not all prokaryotes are harmful to humans. It’s about less than 1% of prokaryotes (which are all bacteria) that are thought to be human pathogens and harmful to them.
It’s is also interesting to note that, collectively these 1% prokaryotic species are responsible for a large number of the diseases that harm humans.
Moreover, besides pathogens that have a direct impact on human health. Prokaryotes also affect humans in many indirect ways like damaging crops, etc.
Prokaryotes are those organisms that lack a distinct nucleus and other membrane-bound organelles and are usually one celled-living organism.
They possess a simple-living cell with not many functionalities. They are microscopic, single-cell organisms that live almost everywhere.
Bacteria like prokaryotes live in every climate and location on earth and, even inside humans and plants causing pathogenic activities.
We’ll know it all. So, just keep reading!
Prokaryotes cause half of all human diseases
Bacteria are among the best-known prokaryotic organisms. Here we will talk only about bacteria that act pathogenic to humans.
Bacterias are different and can cause disease upon entering the body. Those bacteria that cause the disease are called pathogens.
A typical bacterial infection is simply the proliferation of a harmful strain of bacteria on or inside the body.
Bacteria itself can create the disease or the virus that has used the bacteria as a host to enter the body can create the disease.
Bacteria can infect any area/part of the human body from skin to brain and even in rare cases the bones as well.
It is to be noted that almost all of our body surfaces that includes the skin, gut, mucosa membranes, etc. are covered with bacteria. In fact, our body occupies about 10 times more bacterial cells than a human actually needs.
Some of these bacterias can cause diseases if your immunity (defense mechanism) of the body fails to protect it.
In many cases, these bacterias are so virulent that the body’s defense mechanism can’t stop it from entering the body and so they cause many harmful diseases to humans.
Prokaryotic Bacteria causes half of all human diseases. A few of the well-known diseases caused by bacteria are listed below:
Skin Diseases: These affect the Skin mainly.
- Boils: Caused by Staphylococcus aureus, it shows firm, red, tender bumps that progress until pus accumulates underneath the skin.
- Cellulitis: Caused by Staphylococcus aureus, it forms a painful red infection layer on the skin that is usually warm to the touch.
- Folliculitis: Caused by Staphylococcus aureus, it is an infection of the hair follicles that causes red, swollen bumps that look like pimples.
- Carbuncles: Caused by Staphylococcus aureus, it makes the infected mass to fill with fluid, pus, and dead tissue.
Food Poisoning: These affect the gastrointestinal region mainly
- Botulism: Caused by Clostridium botulinum, causes double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, and muscle weakness.
- Listeriosis: Caused by Listeria monocytogenes, it causes diarrhea, fever, headache, and sometimes resulting in lifelong harm and even death.
- Salmonellosis: Caused by bacteria Salmonella, it causes diarrhea, fever, and stomach cramps.
- Staph food poisoning: Caused by Staphylococcus aureus, it shows nausea, vomiting, and stomach cramps. Most people also have diarrhea.
Sexually Transmitted Diseases: It mainly affects the sex organs and the urinary bladder.
- Chlamydia: Caused by Chlamydia trachomatis, it shows pain when urinating, itching in the urethra, watery discharge from the tip of the penis in men & in women it shows pain when urinating, unusual vaginal discharge, pain in the tummy or pelvis, unusual bleeding through the vagina.
- Gonorrhea: Caused by Neisseria gonorrhoeae, it can increase the risk of pelvic inflammatory disease (PID) in women.
- Syphilis: Caused by Treponema pallidum, it shows a mild fever, fatigue, sore throat, hair loss, weight loss, swollen glands, headache, and muscle pains.
Prokaryotic bacteria typically cause diseases by releasing Endotoxins and Exotoxins
Prokaryotic Bacteria produces Endotoxins and Exotoxins which when released into the body causes diseases and shows various bad symptoms.
Exotoxins are usually heat-labile proteins, meaning that these proteins can be easily destroyed or deneturated in the excess of heat. Exotoxins are secreted by certain species of bacteria that diffuse into the surrounding medium.
Exotoxins are usually excreted from the inner portion of the bacterial living cell. These are found in both Gram-positive and Gram-Negative bacteria.
Endotoxins on the other hand are the integral part of cell wall and is only secreted when the cell wall breaks.
Endotoxins come out from the inner portion of the bacterial cell wall and these are mostly found in Gram-Negative bacteria.
Whenever the bacteria enter the living human body, exotoxins are immediately released into the surrounding environment whereas, endotoxins are not released until and unless the bacteria gets killed by the body’s immune system of the body..
Sometimes endotoxins may also be released from growing bacterial cells and cells that are lysed as a result of effective host defense (e.g. lysozyme) or by the activities of certain antibiotics (e.g. penicillins and cephalosporins).
In one way or the other, these toxins get released from the bacteria, thus disrupting the host’s metabolic pathways. These include damaging cell membranes, disrupting protein synthesis, inhibiting neurotransmitter release, or activating the host immune system.
The mechanisms of action by which toxins disrupt eukaryotic cell processes are dependent on the target of the bacteria and its toxin type.
This resultantly creates various symptoms and inflammatory reactions in the effecting part of the body.
Prokaryotes break off the body’s defense mechanisms
Prokaryotic Bacteria can break off the body’s defense mechanisms and can enter the body to cause its disease.
Our body is covered by millions to billions of prokaryotic bacterias. Not all bacterias present in the surface of the body are harmful in nature.
And those that are harmful can’t actually enter the body so easily due to the host body’s strong defense mechanism. But, the most virulent ones can surpass that defense mechanism and can enter.
The body’s defense system includes the protection by the skin, nails, and hair forming the integumentary system which stops dirt and pathogens from entering the body. You also have the internal defense systems, which include white blood cells and the antibodies they produce for defense.
The process of surpassing the host’s primary and secondary defense mechanisms of the body and entering the cells and the tissues by secreting invasins by the bacteria thus causing the breaking off the body’s defense mechanisms.
This lets the bacteria to simply enter the body and cause its pathogenicity and the various diseases and the symptoms.
Mechanism of Prokaryotes that infect Humans
We have learned that the prokaryotic bacteria infect humans and so they are harmful. But, do you know how do they infect the humans?
Infection is basically on the basis of the relationship between a host (human) and a pathogen (bacteria) which is dynamic since each modifies the activities and functions of the other.
The outcome of such a relationship between a host (human) and a pathogen (bacteria) depends on the disease-causing ability (virulence) of the pathogen and the level of resistance of the host to protect itself from having the disease with the aid of the host defense mechanisms.
Mechanisms of Bacteria that infect humans go through the three steps of Pathogenicity to cause the disease:
1. Colonization: Colonization is actually the presence and adherence of bacteria on a body surface like that on the skin, mouth, intestines, or nasal cavities, through which the various species of bacteria can enter the body, without causing any disease in the person. In this step, the bacteria are actually multiplying and preparing themselves with a variety of mechanisms to fight the surface defense system of the body and enter inside it.
2. Invasiveness: Invasiveness is the process through which the bacteria have successfully entered the host’s body by the production of bacterial extracellular substances (invasins) that act against the host by breaking down primary or secondary defenses of the body. This leads to the entry of the bacteria into the host’s cell and tissues and this causes the disease.
3. Toxigenesis: Toxigenesis is the ability to produce toxins once the bacteria has successfully invaded the cell. Either Exotoxin or Endotoxin may be released or, in rare cases, both are released by the same bacteria. These toxins are transported by blood or lymph and cause cytotoxic effects at the tissue sites and this shows the symptoms of the disease caused.
Prokaryotes are economically harmful to humans as well
Prokaryotic Bacteria not only harm humans directly but also indirectly. At this point, we are not talking about the health issues of the humans.
But, in fact, we are talking about the economic loss and harms that these organisms do to the humans. In either way its harmful.
You must not that bacterial diseases cause multi-billion dollars loss to the livestock and agricultural industry as well.
Diseases caused by Prokaryotic bacteria in the various livestock and other industries which leads to major economic harm and loss:
1. In Apiculture: Americal foulbrood disease (AFB), European foulbrood disease (EFB), etc.
2. In Sericulture: Bacterial Flacherie disease, Septicemia, Sotto disease, Court disease, etc
4. In Poultry Farming: In Chicks bacterial diseases like Omphalitis, Salmonelloses, Paratyphoid infections, Fowl cholera, Riemerella anatipestifer infections, Mycoplasma, Necrotic enteritis, etc. are seen. In Duck, Duck Cholera, Botulism, etc. are more common.
5. In Aquaculture: Yersiniosis (enteric redmouth disease) in salmonids; Edwardsiella ictaluri causes enteric septicemia in catfish; columnaris disease, coldwater disease, and bacterial gill disease of marine fishes; Bacterial kidney disease in cultured salmonids; mycobacteriosis in fishes; Rickettsial disease associated with Piscirickettsia salmonis; Franciselliosis disease in a variety of aquacultured and wild-caught species.
6. In Dairy Farms: In cow it causes E. coli disease, Mad cow disease, Campylocater disease, Brucellosis disease, etc.
7. In Agriculture: Black rot (Xanthomonas campestris pv. campestris), Bacterial canker (Clavibacter michiganensis pv. michiganensis), Bacterial soft rot (Pseudomonas spp., Erwinia spp.), Bacterial leaf spot/Bacterial spot (Xanthomonas campestris – various strains), Bacterial wilt (Ralstonia solanacearum), Bacterial leaf spot/Bacterial spot/Bacterial blight (Pseudomonas syringae – various strains), Bacterial blight (Pseudomonas syringae pv. pisi), Bacterial brown spot (Pseudomonas syringae pv. syringae), etc.