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.
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!
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?
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.
The Amazon Molly reproduces without any genetic contribution from a male (click for credit)Most biology students know that there are two forms of reproduction: sexual and asexual. In sexual reproduction, the genome of the offspring is made from two contributors: the male parent and the female parent. In asexual reproduction, a single organism reproduces, and the offspring are genetically identical (barring any mutations) to the single parent. In general, bacteria reproduce asexually, while most animals and plants reproduce sexually. However, there are some animals that can reproduce asexually. Sea stars, hydra, and planarians are examples.
What most biology students don’t know is that there are examples of individual species of animals that reproduce asexually, even though other very similar animals reproduce sexually. Take, for example, the Amazon molly (Poecilia formosa), which is pictured above. It is thought that this species arose when a female Atlantic molly (P. mexicana) sexually reproduced with a male sailfin molly, (P. latipinna). While both the mother and the father (as well as all other members of the genus) reproduce sexually, the Amazon molly reproduces asexually. So when this interesting fish produces offspring, they are all genetically identical to the parent, except in certain rare instances, such as when mutations occur.
Now interestingly enough, there are a few forms of asexual reproduction in animals, and the one employed by the Amazon molly is called “gynogenesis.” In this form of asexual reproduction, a male is needed, but he contributes nothing to the genetics of the offspring. Essentially, the female produces eggs that have the full complement of genes (technically called a “diploid egg”), but they cannot begin development into offspring until they are stimulated by the presence of a male’s sperm. The problem, of course, is that all Amazon mollys are female. As a result, the Amazon molly “mates” with similar fishes, usually ones from the same genus.
One really interesting question related to all this is, “Why is it rare?” After all, sexual reproduction is annoying. You have to find a member of your own species that is the opposite gender. The Amazon molly’s form of asexual reproduction still requires a male, but it can be from a wide range of species. As a result, it is much easier for the Amazon molly to find a mate. Why, then, isn’t this kind of reproduction found very often in animals?
I recently commented on NASA’s paper regarding bacteria that can successfully incorporate arsenic into their biochemistry. Well, another blogger who has more expertise related to the paper has posted a very critical analysis. It is worth reading.
Essentially, the blogger believes that it is very possible the bacteria that lived in the arsenic-only cultures might have been scavenging phosphorous from others in the population that had died. As a result, the blogger is skeptical that arsenic was incorporated into the bacteria’s biochemistry to any meaningful extent.
The blogger is especially critical of the analysis claiming to have found arsenic incorporated into the bacteria’s DNA. He thinks the DNA-related data can be explained by contamination:
If this data was [sic] presented by a PhD student at their committee meeting, I’d send them back to the bench to do more cleanup and controls.
Based on the comments, it seems the blogger is sending a modified version of the post to Science as a letter to the editor. It will be interesting to see how the NASA group responds.
“NASA Finds New Life Form” is the headline on the Fox News website. The article says:
NASA has discovered a new life form, a bacteria called GFAJ-1 that is unlike anything currently living in planet Earth. It’s capable of using arsenic to build its DNA, RNA, proteins, and cell membranes. This changes everything…NASA is saying that this is “life as we do not know it”. The reason is that all life on Earth is made of six components: Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. Every being, from the smallest amoeba to the largest whale, share the same life stream. Our DNA blocks are all the same. That was true until today.
While the NASA team has done something quite amazing, Fox News and other similar outlets have really over-hyped it. Not surprisingly, to get the real story, you must read the scientific article, which is groundbreaking indeed, but not in the way that the standard media outlets are saying.
We now know that some bacteria can walk
(Click Image for credit)The hostess says, “Hold on there. We don’t allow bacteria in this fine establishment.” The bacterium says, “It’s okay…I’m staph!” It’s a stupid joke, I know, but at least the beginning isn’t scientifically inaccurate. It turns out that some bacteria can, indeed, walk!
Microbiologists have already shown that bacteria can swim through liquid using their amazingly well-designed flagella. They have also found that bacteria can crawl along a surface. However, no one had ever caught them in the act of walking until a team of UCLA researchers started studying the dynamics of bacterial biofilms.
The researchers were studying Pseudomonas aeruginosa, a species of bacterium found in soil, water, and many human-made environments. It can cause lung, skin, eye, and gastrointestinal infections. Like many bacteria, members of the species can exist as either free-swimming individuals or surface-clinging colonies. The surface-clinging colonies form biofilms.
Interestingly enough, a free-swimming bacterium can be genetically identical to a member of a biofilm. However, because the two different lifestyles have different requirements, some genes are active in the free-swimming bacteria but not in the biofilm bacteria, and vice-versa. This switching on and off of genes produces bacteria that look and behave quite different, even though they have the same genome.
Velvet worms make amazing slime! (public domain image)As a chemist, I have always loved slime. There are so many different kinds of slime and so many different ways to make it! For example, you can make slime at home using glue, water, and borax. You can also make it using water, cornstarch, and some heat. Both slimes are different, and they both bring out the kid in me. Chemistry really can produce great stuff! Of course, nature does a far better job at chemistry than even the best of today’s chemists. Indeed, the best chemists in the most sophisticated chemistry labs on earth cannot begin to make many of the sophisticated chemicals that a “simple” bacterium makes every day!
There is an obvious reason for this, of course. While chemistry has developed over thousands of years and was guided by some incredibly intelligent people, nature was made by God. As a result, you expect nature to be filled with things that put the most amazing achievements of chemistry (and science in general) to shame. Of course, that’s exactly what you find. From the best possible design for the vertebrate eye to the lightning-fast chameleon tongue, nature’s designs are significantly better than anything human science can produce. Indeed, world-renowned atheist Antony Flew had to give up his atheistic faith specifically because of the amazing design he saw in nature.
Well, it turns out that even some of nature’s slime is amazing!
A bumblebee has a small brain but can do complex calculations (click the image for its credit)As I mentioned in a previous post, because they are not willing to understand that it has been designed by an incredibly intelligent and powerful Designer, evolutionists are forced to look at nature in a ridiculously simplistic way. Take the naive evolutionary idea that brain size correlates with intelligence. Because evolutionists can’t appreciate the incredible design that went into producing brains, they generally assume that the smaller the brain, the lower the intelligence of the organism. Nearly a year ago, I reviewed The Design of Life , which discusses some powerful evidence against this silly notion. Recent research1 on bumblebees has just added more evidence to the pile.
In the research, the investigators wanted to know how a bumblebee decides the order in which it visits flowers. It has been observed for quite a while that bees tend to visit the flowers they have identified as good food sources in a predictable order. In other words, they don’t fly “willy nilly” amongst the flowers they visit. Instead, the have a planned flight route. This has been called trapline foraging, because human trappers typically follow a preplanned route when checking the traps they have set.2
The question the authors wanted to address was how the bees arrive at their preplanned “trapline” route. Do they just visit the flowers in the same order in which the flowers were originally discovered, or is there more thought given to the process? In the end, the researchers were able to show that there is a lot of thought devoted to the process.
