Microbial Me

Bacteroides trichoides, one of the many species of bacteria that live in the human intestine (CDC image)
One of the most fascinating aspects of the biological world is the phenomenon of mutualism – two or more different species living together so that each organism benefits. I have blogged about this topic before (here, here, and here), and I discuss it quite a bit in my science texts. Technically, it is a subcategory of symbiosis, where two or more organisms live together. If all organisms benefit from this living arrangement, we call it mutualism. If one benefits and the others are not harmed, we call it commensalism. If one benefits and another is harmed, we call it parasitism.

Many scientists consider mutualism (and symbiosis as a whole) to be a fairly uncommon thing in nature. Sure, you can find some organisms that help each other out from time to time, but overall, nature is about organisms “battling it out” for survival. Nothing could be further from the truth! While organisms do compete against one another in nature, they also help each other quite a bit. As George D. Stanley, Jr wrote a few years ago in the journal Science:1

Symbiosis is the most relevant and enduring biological theme in the history of our planet.

Indeed, symbiosis (and mutualism in particular) is incredibly common throughout creation, and nothing makes that more apparent than a study of the microbiological communities that live in each one of us.

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New Survey in Science Shows That Evolutionary Propaganda Isn’t As Effective As Some Had Hoped

The journal Science recently reported on the results of The National Survey of High School Biology Teachers.1 This survey studied the teaching habits 926 public high school biology instructors that are supposed to be representative of the nation as a whole. The results cause alarm in some and hope in others.

The “take home” result is that 13% of the teachers surveyed spend at least one hour teaching either creationism or intelligent design in a positive light. In contrast, 28% of teachers are strong advocates of evolutionary biology, stressing it as a unifying theme in the life sciences. The majority (roughly 60%), however, advocate neither position. In fact, many of them spend as little time as possible on the subject of origins.

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DNA Is Even More Complex Than We Thought!

An Illustration of DNA.
Author: Kevin Spear
James D. Watson and Francis Crick are credited with determining the basic structure of DNA. They had been studying an enormous amount of data that had been collected on DNA, and in a brilliant flash of insight, they came to the conclusion that DNA is shaped like a spiral staircase. The “stairs” on the staircase were composed of two nucleotide bases linked together. There are four nucleotide bases in DNA: adenine (A), thymine (T), cytosine (C), and guanine (G). In their model, A could only link to T and C could only link to G. This has become the generally-accepted view of DNA’s molecular structure, and a simplified illustration is shown on the left.

One of DNA’s elegant features is that the nucleotide bases are linked together with hydrogen bonds. Unlike their name implies, hydrogen bonds aren’t really chemical bonds at all. Instead, they are very strong attractions that exist between a hydrogen atom on one molecule and another atom (typically oxygen or nitrogen) on another molecule. Because hydrogen bonds are not true chemical bonds, they are not nearly as strong as chemical bonds. As a result, they can be “broken” with only a small amount of energy.

It turns out that this is the perfect design, because in order for DNA to code for proteins, the double helix must “open up” to expose the nucleotide bases. To do this, the link between the nucleotide bases must be broken. If the nucleotide bases were held together with chemical bonds, it would take a lot of energy to break the link, and that energy could easily damage the other bonds in DNA. Since the nucleotide bases are linked with hydrogen bonds, however, it takes only a small amount of energy to break the link. As a result, DNA can “open up” very easily, and the rest of the molecule is not harmed when that happens.

Watson and Crick determined all this, including exactly where the hydrogen bonds formed. Not surprisingly, the way in which the links form is called Watson-Crick pairing. Well, it turns out that there is another way the nucleotide bases can pair up, and a recent study shows that this is yet another amazing design feature of DNA.

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Here’s How Desperate Naturalists Are Becoming

This illustration shows that some molecules form two isomers that are like hands. They are mirror images but are not superimposable.
(Image courtesy of NASA)
Naturalistic evolutionists face many problems, most of which are the result of the fact that science doesn’t support what they want to believe. As a result, they must make up desperate explanations to work around what science clearly says. Nowhere is this more true than in origin-of-life research. Serious scientists understand that life comes only from other life. That’s what all the data clearly demonstrate. However, a naturalistic evolutionist simply cannot believe that. As a result, he or she must cook up wild scenarios by which nonliving chemicals can react with one another to magically create life.

Of course, there are countless problems with such wild scenarios. Demski and Wells recount many of them in their book, The Design of Life. Simon Conway Morris has an even more devastating review of the various origin-of-life scenarios in his book, Life’s Solution. One of the many intractable issues in any naturalistic origin-of-life scenario is chirality.

There are many molecules that have the same chemical formula but are quite different chemically. Glucose, for example is the sugar found in green, leafy vegetables. Fructose, on the other hand, is the sugar found in fruit. They are chemically quite different (which is why they taste different), but they have the exact same chemical formula: C6H12O6. They are chemically different because despite the fact that they contain exactly the same complement of atoms, the atoms arrange themselves into differently structured molecules. We call such molecules isomers.

There are many kinds of isomers, and one specific kind is a stereoisomer. Consider your hands. They are mirror images of one another. If you hold them together at the palms, your fingers and thumbs all match. However, if you try to lay one of your palms on the back of your other hand, your fingers and thumbs will not match. Your thumbs, for example, will be on opposite sides. In other words, while your hands are reflections of each other, they cannot be superimposed on one another. There are molecules like that as well. They are mirror images of each other, but there is no way you can turn one of the molecules around and make it look exactly like the other molecule. Such molecules are called stereoisomers. Because they are like your hands, we actually refer to one stereoisomer as the “left-handed” isomer and the other as the “right-handed” isomer.

An example of such a molecule is shown in the sketch above. The amino acid alanine can be formed two ways. Like your hands, those two molecules are mirror images of each other, but there is no way you can turn one of those images into an exact replica of the other. If a molecule has a stereoisomer, it is called a chiral molecule, and chiral amino acids cause all sorts of headaches for those who want to believe that life sprung from nonliving chemicals.

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Oh No! He’s Wrong Again!

Susumu Ohno is famous for postulating the existence of “junk DNA.” In his paper introducing the term, here is what he wrote about DNA sequences that he thought were nonfunctional:1

Our view is that they are the remains of nature’s experiments which failed. The earth is strewn with fossil remains of extinct species; is it a wonder that our genome too is filled with the remains of extinct genes?

Of course, as time went on, we slowly learned how wrong Ohno was in this assessment. While many DNA sequences are not used to produce proteins, specific functions have been found for much of this supposed “junk.” Indeed, as more and more functions have been found for more and more “junk” sequences, it is becoming increasingly clear that very little junk exists in the genome.

While Ohno did some marvelous work in his illustrious career, much of it was hampered by the blinders of evolution. When you are compelled to believe that nothing but natural processes are responsible for life, you simply cannot see the deep complexity of creation. As a result, you force simplistic ideas on science, whether the data support them or not. The idea that much of an organism’s genome could be filled with “junk DNA” is a perfect example of how evolutionary thinking produces absurd conclusions.

Recently, Yuanyan Xiong and colleagues have laid to rest another evolution-inspired idea that originated with Susumu Ohno.

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The Amazing Design of Human Tears

Tears do some amazing things!
(click image for credit)
You probably don’t think about them very often, but tears are amazing. They are produced continually by your body’s lacrimal glands in order to lubricate your eyes as well as various tissue membranes associated with your eyes. They generally drain away through two structures called the lacrimal punctua. This is why you normally don’t notice your tears. However, if your lacrimal glands start producing tears too quickly for them to be drained away, they collect in your eyes until they eventually fall down your cheek. At that point, you (and other people) notice them, because you are crying.

There are two reasons for crying: eye irritation and strong emotions. If dust or other debris gets into your eyes, your lacrimal glands start producing a lot of tears in order to flush out the debris. All creatures with moveable eyes can cry because of irritation. I will call the tears produced by this kind of crying “irritant tears.” The chemical content of irritant tears is not all that surprising. In addition to oils for lubrication, water, and salt, they contain a powerful enzyme called lysozyme. This broad-spectrum antibiotic helps to prevent eye infections.

The second reason for crying has inspired today’s blog. A friend of mine sent me a news story regarding some new research that has been done on tears that are the result of emotion. Interestingly enough, she I and disagree strongly on what should trigger emotional tears (I am an old sap – she rarely cries for emotional reasons), but she knew the story would be of interest to me. When I looked a the study that generated the news story, it reminded me of some old research that was done on tears. Together, the old and new research tell us a lot about how amazing tears are.

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What Makes Bone So Strong?

Even this electron microscope image of hydroxyapatite crystals in bone doesn't reveal its amazing secret.
(Public domain image)
Bone is a truly incredible substance. It is as strong as steel but at as light as aluminum. Not only is it strong, but it is surprisingly flexible as well. As is the case with most things God made, human technology cannot come close to producing something with bone’s amazing properties. Consider, for example, the work of Antoni Tomsia at Lawrence Berkeley National Laboratory in California. He and his colleagues are trying to artificially produce something with the characteristics of bone, but they simply cannot come up with anything as elegant and sophisticated as bone. He says:

People want a strong, light, and porous material, which is almost a contradiction in terms, but nature does it…Bone is made from calcium phosphate and collagen, which are both extremely weak. But nature mixes them together at room temperature and without toxic chemical [sic] to create something that is very tough — this fascinates us.

What makes bone so special? The short answer is that we don’t really know. However, we are learning. For quite some time now we have known that bone is a mixture of many things, principal among them a protein called collagen and a calcium compound called hydroxyapatite. The collagen gives bone its flexibility, while the hydroxyapatite gives bone its strength.

However, the hydroxyapatite in bone is stronger than hydroxyapatite made in the lab. Why? It has to do with the size of the crystals. When hydroxyapatite is made artificially, the individual crystals that form are very large. In bone, the crystals are very small, on the order of 3 billionths of a meter long. These nanocrystals have long been thought to be the reason that hydroxyapatite in bone is so strong. However, scientists haven’t been able to understand why the nanocrystals stay so small in bone.

Now Klaus Schmidt-Rohr and his colleagues might just have figured that part out!

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Bacteria That Cause Tooth Decay….Good for you?

A human mouth infected with thrush.
(Image in the public domain)
You are looking at the inside of a person’s mouth. I know…the picture is gross. However, sometimes science is gross. You just have to get used to it. In my opinion, the science is well worth the gross picture. What makes this picture more gross than most pictures of a person’s mouth is that this mouth is infected with a yeast called Candida albicans. That’s what is causing the yellow gook you see in the mouth. This infection, commonly called thrush, is not very serious. Of course, it’s not very pleasant, either.

Interestingly enough, the yeast in question is called a dimorphic fungus. This means it can exist in one of two forms. It can exist as a collection of individual yeast cells, or it can grow threadlike structures called hyphae. These hyphae clump together to form a fungal body called a mycelium, which is what you are looking at in the gross picture above. The microscopic photo below shows you both forms of Candida albicans.

Candida Albicans in both forms. Click image for credit.

So if you have Candida albicans in your mouth, you won’t have thrush as long as the cells don’t form hyphae. If they stay in their yeast cell form, your mouth won’t look like the picture above. The interesting question, of course, is what keeps them from forming the hyphae?

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“Conserved DNA” and “Useful DNA” – An Evolutionary Predicament

As I have stated before, naturalistic evolutionists are forced to have a very simplistic view of life. Since they cannot accept that life was designed by an incredibly intelligent designer, they are forced to look at life through a ridiculously simplistic lens. This produces all sorts of problems for them. One of the more recent ones involves the amount of DNA that is “conserved” in class Mammalia.

For those who don’t know the term, “conserved DNA” is DNA that is similar across many different species. In the simplistic evolutionary view, DNA that is very important will be very similar in many different organisms, because important DNA cannot change very much. As Tina Hesman Saey writes in Science News1

About 7 percent of the human genome is similar to the DNA of other mammals, said Arend Sidow of Stanford University. Because it is similar, or “conserved,” geneticists assume this DNA is the most integral.

As Saey’s article indicates, this leaves Sidow to conclude that, “very little of the human genome is really necessary.” According to evolution, if only 7% of the human genome is conserved across all of class Mammalia, this indicates that most mammalian DNA was mutating freely, with very little constraint, during the long period of mammalian evolution. This, in turn, indicates that most mammalian DNA does little to affect the survivability of the mammal in question, and thus most mammalian DNA is not necessary. Indeed, the title of the article is, “Genome may be full of junk after all.”

Like most evolution-inspired ideas, however, this flies in the face of what science tells us about DNA.

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I Always Knew Cats Were More Elegant…

Cats have an elegant means of drinking. (Click for image credit)
I have always been a cat lover. It’s not that I don’t like dogs; I do. In fact, I have one friend who says his dog misses me for a while every time I leave his home. Nevertheless, when it comes to what pets I want to have in my home, cats win over dogs every time. I have always found cats more… well… elegant than dogs. Now, a new study confirms this is true, at least when it comes to how they drink.

Pedro M. Reis, the lead author of the study, was watching his cat (Cutta Cutta) drink one day. He knew that like dogs, cats cannot use their cheeks to suck in liquid. Thus, they must pull liquid into their mouths using their tongues. As he watched his cat, he wondered what physical mechanisms were at work. He thought surely someone had studied how cats drink water before, but the best thing he could find was a 1940 film called Quicker ‘n a Wink, which featured MIT professor Harold “Doc” Edgerton.1 While it had some nice high-speed photography of a cat drinking, it didn’t really explore what was going on in terms of the physics involved. As a result, his team decided they would find out for themselves.

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