The genera Escherichia is thought to have emerged around 102 million years ago and is known as a gram-negative pathogenic bacteria mostly found in the intestines of warm blooded animals [1]. German pediatrician and bacteriologist Theodor Escherich discovered E. coli in 1885, and for many years the bacterium was simply considered to be a commensal organism of the large intestine. It was not until 1935 that a strain of E. coli was shown to be the cause of an outbreak of diarrhea among infants [2]. The reason its pathogenic properties were discovered so late is that many of its strains are harmless. However, virulent strains of E. coli can cause various diseases in humans and in domestic animals, and are also sometimes responsible for product recalls due to contamination. Gastroenteritis, urinary tract infections, and neonatal meningitis are the most commonly observed diseases in humans, and in rare cases virulent strains are also responsible for haemolytic-uremic syndrome, peritonitis, mastitis, septicaemia and Gram-negative pneumonia [2]. Various outbreaks all around the world have been caused by E. coli, causing millions of deaths and sick people and billions of dollars have been spent fighting it. Even though death rates have decreased with the evolution of modern medicine and the discovery of antibiotics, the outbreaks are still a major concern for all countries, such as the recent outbreak in Germany in 2011 affecting 3,950 people and killing 53 [3].

Its reputation has not been one of great dignity, and it has ruined the reputation of many. You may recall in 1993, the fast food chain restaurant “Jack in the Box” suffered a major corporate crisis involving E. coli O157:H7 bacteria. Four children died of hemolytic uremic syndrome and 600 others were reported sick after eating undercooked patties contaminated with fecal material containing the bacteria at locations in Seattle and the Pacific Northwest, USA. The chain was faced with several lawsuits, each of which was quickly settled but left the chain nearly bankrupt and losing customers.

But don’t these creatures have any properties to be appreciated, I wonder…

Compared to eukaryotic cells, bacteria have a pretty basic mechanism of functioning. They don’t have sophisticated organelles, and they do not have a cell nucleus where their DNA is stored. Everything is floating along all together in the cell cytoplasm (which shocks me when I reflect upon how such a small and simple organism can cause such severe pain on “highly evolved modern humanity”). It has the basic metabolic tools for survival. And even though, at first sight, it is tempting to look down on its simplicity, today we know that it is this simplicity that gives us space for making many modifications and experiments on it, whereas in more complicated cells, like animal cells, the moment a modification is made, the entire system reacts to that and causes much trouble in the process.

The turning point of E.coli making a huge impact on our lives was in 1973, when Stanley Cohen and Herbert Boyer discovered the “Recombinant DNA Technology.” This technology allowed specific genes to be isolated from one organism and cloned to another organism by the help of bacterial plasmids. The first commercial product to be synthesized by this technology was human insulin, which is used for the treatment of diabetes [4]. This brought an amazing amount of recognition and appreciation for the technology, as the practical aspect of the technology was now proven to be commercially profitable. For the insulin to be produced, the DNA sequence that encodes human insulin was synthesized and transplanted into a plasmid that could be maintained in a non-pathogenic strain of E.coli [4]. Now the bacterial host cells acted as biological factories for the production of the two peptide chains of human insulin, which, after being combined, could be purified and used to treat diabetics who were allergic to the commercially available porcine (pig) insulin, or for diabetics from certain religious groups who abstain from pork products such as Muslims, Jews, some Christian groups, and many more who have similar concerns.

This was only the start of an incredible new technology which used bacteria to produce different proteins or enzymes to cure human diseases. Today more than 200 new drugs have been produced by recombinant DNA technology and have been used to treat over 300 million people for diseases such as cancer, multiple sclerosis, cystic fibrosis, and stroke, and to provide protection from other infectious diseases. Over 400 new drugs are in the process of being tested in human trials to treat such diseases as Alzheimer disease and heart disease (to name only two) [4].

Today E.coli is frequently used as a model organism for all kinds of microbiological experiments. In the lab, E. Coli. is one of the first micro-organisms that is thought of for testing a biological experiment. The reason is that E.coli cells are cheap to purchase and to sustain. They grow easily and rapidly in lab conditions and have non-pathogenic strains, so they are not dangerous for the researches doing the experiment. Whereas purchasing more complicated cells such as cancer cells or stem cells may be very costly, and moreover, may need special lab conditions to be sustained; so before more complicated cells are purchased, the experiments are usually tried out with E.coli or some other kind of model organism. More importantly, E. coli was one of the first organisms to have its genome sequenced; the complete genome of E. coli K12 was published by Science in 1997 [5]. Other areas in which modified E.coli has helped humanity are vaccine development, bioremediation (fighting pollution), and production of immobilised enzymes [6].

One specific example of the benefit of recombinant DNA technology for the environment is its use in the paper industry. Before the 1970’s, when there wasn’t much environmental awareness in the paper producing industry, poisonous chlorine compounds were conventionally used to achieve pulp brightness of a high order in the manufacture of high-quality paper products [7]. This chemical bleaching technique precipitated a tremendous environmental concern considering the magnitude of the industry. Plants treated with elemental chlorine produced significant amounts of dioxins. Dioxins are highly toxic, and their health effects on humans include reproductive, developmental, immune and hormonal problems. They are also known to be carcinogenic. Over 90% of human exposure is through food, primarily meat, dairy, fish and shellfish, as dioxins accumulate in the food chain in the fatty tissue of animals [7]. One alternative for these chemical bleaching processes is the use of the enzyme “xylanase,” which degrades the linear polysaccharide beta-1,4-xylan into xylose, thus breaking down hemicellulose, one of the major components of plant cell walls. Even though the use of xylanases in this industry has increased significantly with the discovery of Viikarri et al. (1986), the enzyme needs further improvements for it to be commercially acceptable [6]. To ensure the commercial utilization of hemicellulosic residues in the pulp and paper industries, the production of higher xylanase yields at low capital cost is required [6]. Such studies are ongoing with the purpose of partially mutating the amino acid sequence for the purpose of especially increasing the thermal stability of the enzyme and also increasing its metabolic activity. The gene mutation and gene expressions are generally done in either E.coli or yeast cells. Davoodi et al. has mutated the enzyme up to the point where the transition temperature increased 12 0C by introducing disulfate bonds in the enzyme [8]. The wonders this enzyme can do for the health of the environment is breathtaking, and is an area which should be further studied until finding the commercially viable kind that will eliminate chemicals from the paper industry during bleaching.

Even though some controversy remains on gene transferring, its tremendous positive impact on humanity cannot be denied. I personally think that it does need constraints and strict regulations, but this technique is one of the most remarkable techniques discovered in modern times, and E.coli has no doubt played a great role in the availability of this technology.

Even though condemning E.coli and stating its “evilness” seems like the most obvious path, we all ought to appreciate the variety and uniqueness of these creatures which also allow us to produce such large varieties of drugs. We ought to appreciate its simplicity, which allows it to have a chance of producing such sophistication. We ought to reflect upon the fact that something can be classified as “good” or “bad” only by the means in which we perceive it, and the reality of it may be completely opposite of what we had thought initially.

McPen is a freelance writer in natural sciences, Montana, US.

References

1. Battistuzzi FU, Feijao A, Hedges SB. 2004. “A genomic timescale of prokaryote evolution: insights into the origin of methanogenesis, phototrophy, and the colonization of land”. BMC Evol. Biol.
2. Todar, K. “Pathogenic E. coli”. Online Textbook of Bacteriology. University of Wisconsin–Madison Department of Bacteriology.
3. “German-grown food named likely culprit in deadly outbreak”. CNN. (5 June 2010).
4. Glick, Bernard, Jack Pasternak, and Cheryl Patten. 2010. “MOLECULAR BIOTECHNOLOGY Principles and Applications of Recombinant DNA . 4th Edition.” Washington,DC: ASM Press, pp. 3-13.
5. Blattner FR, Plunkett G, Bloch CA, Perna NT, Burland V, Riley M, Collado-Vides J, Glasner JD, Rode CK, Mayhew GF, Gregor J, Davis NW, Kirkpatrick HA, Goeden MA, Rose DJ, Mau B, Shao Y (September 1997). “The complete genome sequence of Escherichia coli K-12”. Science 277 (5331): 1453–62.
6. Cornelis P. 2000. “Expressing genes in different Escherichia coli compartments”. Curr. Opin. Biotechnol. 11 (5): 450–454.
7. Beg, Q.K., M. Kapoor, L. Mahajan, and G.S. Hoondal. 2001. “Microbial xylanases and their industrial applications: a review.” Springer.
8. Davoodi J., Wakarchuk W.W., Carey P.R., Surewicz W.K. 2007. “Mechanism of stabilization of Bacillus circulans xylanase upon the introduction of disulfide bonds.” Biophysical Chemistry, 125 (2-3) , pp. 453-461.

We are three pairs of large glands that secrete into the mouth through canals and hundreds of very small glands around the throat. The large glands in front of the ear area are called the parotid glands, the glands under the chin are called the submandibular glands, and the ones under the tongue are called the sublingual glands. The parotid glands secrete saliva from the sides of the upper molar teeth, the submandibular glands from the front under the tongue, and the sublingual glands from many openings in the mouth’s base. There are also many more salivary glands in your inner cheeks and lips, and in all other wet spots in your mouth and throat.

Every sugary and starchy food you eat must first interact with our secretion in order to be digested. For this, an enzyme called ptyalin has been placed within us. But for this enzyme to work properly you must chew your food well. Also, you shouldn’t eat anything that is too hot or too cold, or anything that could change the pH (acidity) level of your mouth. Otherwise, this enzyme cannot function correctly. We produce an average of about 1000 milliliters (one liter) of secretion every day; however, we have the capacity to produce 1.5 liters of saliva per day.

Sometimes, the calcium in our enzymes may precipitate and form tartar due to acidic foods. Tartar can sometimes block our secretion canals. When you eat something, saliva production accelerates; but if our secretion canals are blocked by tartar, then the saliva cannot flow. This causes infection accompanied by severe pain and swelling. If our canals aren’t completely blocked, we may swell a little while eating, but we will slowly deflate after a while. Microbes can reproduce easier in accumulated saliva that cannot flow, thus causing severe pain and swelling. Our most frequently seen infection is the one that makes the parotid glands swell up, and is called the “mumps”. Even though it is seen more frequently in children, it may also be observed in adults. The swelling of both of the parotid glands is more frequent in alcoholics.

The thiocyanate ions that have been put in our saliva secretion kill the bacteria in your mouth by breaking them apart. In addition, lysozyme enzymes attack and kill bacteria in your mouth while digesting food remains to prevent the bacteria to feed and reproduce. Hungry bacteria perish more easily. Our infinitely merciful Lord put special proteins called anticorps in our saliva to prevent many diseases that can enter from the mouth before they develop. These anticorps act like special agents that attack and destroy bacteria. If we don’t secrete enough saliva, ulcers will develop in your mouth frequently. If they last long enough, they will get infected and also cause tooth decay.

The control of our secretion is connected to an area that includes the appetite center in the brain stem through the involuntary nervous system. When you smell or taste foods you like, we immediately start secreting saliva as a reflex. When you come across foods that you don’t like, or when you get scared or excited, we slow down saliva production, again reflexively. Suspects in the past used to be given a handful of rice to swallow, with the thought that the real culprit would not be able to swallow them, because the excitement caused by the feeling of guilt would cause his/her mouth to dry.

Diabetes, which is a systemic illness, also has a negative effect on our functioning. Diabetes presents itself with drying of the mouth, along with excessive intake of water, and the frequent need to visit the restroom. One type of rheumatoid arthritis may also cause dry mouth and dry eyes together with joint pain.

As you see, Peter, I’ve briefly explained to you how invaluable and necessary your saliva is. I have not even mentioned our histological and anatomical structure, which resembles a bunch of grapes. I believe you can imagine how each and every one of my gland cells is like a perfect biochemical factory. You wouldn’t relate all these to your mouth being wet for no reason, would you?

Irfan Yilmaz is a professor of biology in Dokuz Eylul University, Izmir, Turkey.

I have been placed under the cavity of the chest. So that we do not harm each other, the Creator has placed a membrane between me and my neighbors, the heart and lung; I can hear them, but cannot see them. They are further protected by the rib cage, because they are more sensitive than I. Of course that does not mean that I am without protection. Our Lord has placed all of us in the most appropriate way. If I had bones covering me you would have a lot of difficulty eating and drinking and since you could not store what you eat you would need to eat little portions throughout the day. But since I have been placed in the stomach cavity and all the walls are flexible I can easily store all that you eat and drink until you digest them. This means that you are busy with eating only at certain times, allowing you to spend your time with other things.

I look like a kettle and this rather simple-looking shape might make you undermine my skills. It is for this reason that some people speak of me in a rude way, describing me as “a sack-like organ.” To understand how important I am, ask those with stomach ulcers or stomach cancer. God forbid, should I stop functioning; life would become a living hell. Each drop that you drink and each morsel you eat would be like poison and all of the world’s pleasures would vanish.

My walls, which seem like a simple sack, are made of four layers of special tissue. On the outer layer there is a strong tissue, below this are layers of muscle that have been placed vertically and horizontally in a diagonal manner, and under this there is tissue engulfed in a flexible layer and a final lining called the epithelium. Of course, we should not forget the web of blood vessels and nerves that nourish these thick walls. My system of nerves is such a complex system that you would be amazed; it resembles a second brain and it is aware of your whole body without you being aware. When you hurt your foot or you are upset with the slightest thing or laugh because of joy I am affected by this. This nervous system is so sensitive that it affects all my actions and my digestive excretions.

It is through this nervous system that I control my actions and my excretions when the scent of the food comes and you are getting ready to eat, saving you trouble after you have eaten. I can also be easily trained. If you can stick with it you can get me used to a new life after three days. Some stomachs are used to three meals, while others are content with two or one meal a day. My recommendation is that you get me used to two meals a day.

Not a lot of chemical decomposition can occur in the mouth, so all the nourishment you have eaten needs to pass through me before it is digested by the intestines and it becomes part of your body. What happens is that the things you have eaten are broken up mechanically into little pieces by the teeth so that I can accept them. If you hurry and swallow without chewing and do not soften the morsels you tire me out. In addition to this, if the morsels are sharp or too large they can rip the walls of the esophagus and make them bleed. It is best to chew the morsel 30 times, but unfortunately most people do not do this. They send me mouthfuls after having only chewed on it once or twice. They do not realize that they are full and therefore eat too much, disturbing the balance. If you eat slowly I will let the relevant section of the brain know and the feeling of hunger will stop after you have received enough nutrients. In this manner you do not tire me out too much and the nutrients do not go to waste. If you eat too fast I will be full before I get a chance to bring to the surface the molecules that give the sensation of being full and there will be no room for water or air, which allow me to move comfortably.

There are three different types of cells on the mucous layer that lines the inner layer of my walls and which is in contact with the food. One of these excretions is hydrochloric acid (HCl). This acid, which can dissolve even a piece of rock, is used not only to digest all the meat and proteins, but it also kills any bacteria that may come with the food and beverage. Without this acid the pepsinogen enzyme, which breaks down the protein, cannot be activated. The pepsinogen enzyme also synthesizes some other cells. This enzyme cannot function on its own and cannot be excreted if I do not have food in me. It starts to be excreted together with the hydrochloric acid as soon as I start to be filled with food. So how is it that such a strong acid and protein digesting enzyme do not harm my walls? My Creator has provided my lining with a temporary protective layer. The goblet cells that excrete this protective mucous are so sensitive that they excrete a protective liquid that coats it. Every day I sacrifice one and a half million cells to these enzyme and acids. In other words, every three days my inner layer is destroyed by these corrosive enzymes and acids. But thank God, I have been given me such a revitalizing strength that each day this lining is renewed with new cells.

Sometimes, if there is a problem with the excretion of this protective liquid, the acid and enzyme can start to eat at the stomach walls, leading to blood leaking from the arteries that are in the outer layer; this is known as an ulcer, a wound on my walls. Nervousness and tension affect the excretions in me, and therefore people who have a nervous character can develop ulcers more easily than relaxed people. The best thing to do is to live a life where one faces things with patience, neither being too panicky nor too happy, but living in a balanced and mature way. If you try to live in a balanced way then you will maintain order in the stomach and I will be happy.

You cannot move the muscles of my walls like you can your arm or leg muscles. The muscles are commanded and start working according to orders from an autonomous nervous system that you are not even aware of. An important feature of these muscles is that they work slowly, but take a long time to get tired. At the same time, they are very susceptible to growing if you do not take care of yourself properly; if you are not careful I can swell up quickly like a balloon. The evil side of human character has a very close connection with me; so you have to be very careful not to eat and drink too much and consume unlawful food. Otherwise, you might become weak and be easily misled and consequently this makes me nothing more than a waste container and then I become a pest.

Let me tell you some of the things that I do not like. At the top of the list is very hot or very cold food or beverages. Both ruin the enzymes and make them dysfunctional. The best condition for enzymes to work is at your body temperature-that is 36-37 degrees. There are more scientists today than before who think that overly hot or burnt food can cause my cells to turn cancerous. If you heat very cold items in your mouth and then swallow you protect me from getting cold – because if I get cold I contract and my working balance becomes dysfunctional so that I am no longer able to do my job.

When I finish my job of extracting the nutrients and treating them with the enzymes the food takes on a liquid form. When the food has achieved the desired texture I send it through to the intestines that are right below me. In this regard, I am like this transitory worldly life, which is nothing more than a two-door guesthouse-one door for entrance and the other door for exit. I never retain anything in me-I receive from one end and send it out the other. There is no door between myself and the esophagus, so I can take out what is in me if I have to by vomiting. At first, this vomiting reflex might seem a bad thing and you might wonder why there is nothing to prevent this? But let me remind you of something, what if you mistakenly eat something poisonous or something that has gone off, what would you do if you could not vomit? You would have to be taken to hospital so that you do not die of food poisoning and an incision would have to be made in the stomach; I would have to be cleansed out, but by this time you might have died. However, if I feel that something you have eaten is bad I can remove it. But with the gateway that is placed between myself and the intestines I am able to stop the food in the intestines from coming back to ruin the acidic atmosphere in me, as the enzymes in the intestines work under more neutral conditions. My acidic structure would disrupt the intestine’s enzymes. In particular, if the bile salts excreted from the liver and the pancreas enzymes should spill into me the situation would be very chaotic.

Another important piece of advice I can offer to you Peter is not to play any sports when I am full and not to strain yourself. The thick muscle lining on the walls requires a lot of blood to move. After eating a significant amount of blood is withdrawn from other parts of the body and sent to me. If you try to be active in this state you will suffer, as the rest of your organs will not be nourished properly and stress will be put on your heart.

Here’s another secret I’m going to let you in on: the more you fill me up without thinking about whether it is necessary and lawful or not, the more likely it is that you will make spiritual mistakes. Your spiritual well-being and health are inversely proportional to a full stomach. If you make me grow too much all your veins, starting with your heart, will start to gather fat and therefore their functions will slow down. Also your spiritual side will be dulled. Actually it is enough for a person to eat only what they need to survive. Serving your senses of taste and eating within the allowed parameters by remembering the Giver will not only give me peace but will also take you to spiritual horizons. After the food passes through your mouth it does not make much of a difference to me whether it is sweet or salty. Therefore, if you can take charge of your mouth, which acts as a gatekeeper, you can protect yourself from waste and from putting on extra kilos.

Some time ago some people would laugh at my above advice, and they would say, “Good food is the backbone of life and one should feed well.” But now modern medicine and dieticians have started to give the same advice I have been giving for years and they state that eating enough for sustenance is adequate. Most illnesses arise from over-eating; good food may be the backbone of life, but too much of it is a prescription for an early death.

In particular, with the dietary change that you make during the month of Ramadan, I and my team are able to renew ourselves; it is like a fitness camp that prepares us for a new term. This is an important need for us to start the new season. The time for this is approaching. I expect you will use your will power and allow me to rest as commanded. To continue with your life you need me to provide you the nutrients and energy, because without me even your heart could not function. At the root of all biological sustenance there is a need for food intake. Accordingly, I am like a double bladed sword. You should neither neglect me nor indulge me too much. I hope that you will display this balanced outlook and behavior.