Open wide, as in “ooooooh!”
Scientists have discovered the DNA of millions of microbes trapped in the calcified plaque of four medieval skeletons, which may give clues to what our ancestors ate and the diseases they fought, according to news reports.
Plaque is a biofilm, usually pale yellow that naturally accumulates on teeth. It’s created by multitudinous oral bacteria attempting to attach themselves to the smooth surfaces of your teeth. When you don’t brush well or regularly visit your dentist, it builds up. It’s the stuff scraped away by dental hygienists using whirring grinders and tiny, terrifying stainless steel tools.
In the days of yore, dental hygiene was far less rigorous, of course. Plaque built up on folk’s teeth, layer upon hardening layer, until it completely covered them and was often thicker than the tooth itself.
So brush often and well – and don’t forget to thoroughly rinse off your toothbrush when you’re done. The image above is a single toothbrush bristle covered with microscopic mouth detritus.
The awe of similars
Samuel Hahnemann’s “law of similars" is one of the foundations of homeopathy and the notion that “like cures like.” That is, a substance that produces certain symptoms in a healthy person should be able to relieve those same symptoms in an unwell person.
For example, a person drinking a cup of strong coffee for the first time is likely to experience some or all of the effects of caffeine: racing thoughts, palpitations, increased urine production, shaky hands, excitability and restlessness (which is admittedly why many coffee drinkers consume the stuff in the first place).
According to Hahnemann’s law of similars, coffee should do just the opposite in a sick person already experiencing these symptoms. For example, a homeopath (someone who practices homeopathy) would treat a hyperactive child or an insomniac with a preparation of “coffee cruda,” or unroasted coffee beans. According to homeopathic hypothesis, the caffeine in the cruda would calm the kid and help the insomniac sleep.
Such notions are widely disputed, to say the least. There is very little empirical evidence, broadly accepted, that homeopathic remedies are effective treatments for any specific condition. Indeed, some homeopathic notions, such as medicinal concoctions in which the “active ingredient” has been diluted to the point of no longer actually existing in the concoction, fly in the face of scientific logic and reason.
But this blog post isn’t about celebrating the law of similars but rather the awe of the same. Many, many objects and phenomena in nature appear remarkably alike in appearance, but are, in fact, completely different or unrelated in function or purpose.
Take the two images above: The one on the left is a scanning electron micrograph of different human circulatory system cells: dimpled red blood cells, bumpy white blood cells, called lymphocytes, and disk-shaped platelets. The image on the right is a scanning electron micrograph of diverse pollen grains magnified many times.
A hairy death
Apoptosis or programmed cell death is an essential part of life. For example, it’s critical to human development. Where would we be if every fetal cell survived? Some cells must die to form, say, our fingers and toes; others must perish to shape our functional brains.
Cells frequently commit suicide for the good of the whole. They may become apoptotic in response to viruses or gene mutations in order to prevent further damage. Menstruation relies upon programmed cell death.
Apoptosis may be necessary, but it’s not necessarily pretty. Above is a scanning electron micrograph of several cultured HeLa cancer cells. The cell at the center is undergoing apoptosis. During the process, the cell’s cytoskeleton breaks up, causing the outer membrane to bulge and decouple. The resulting wart-like structures are called blebs, which eventually break off and are consumed by phagocytic cells for recycling.
This is your brain, boiled
Well, not yours obviously, but someone’s.
In its alive and healthy state, the human brain is roughly three pounds of tissue with the reported consistency of oatmeal, though more fun-loving folks might prefer the Jell-O analogy. Men have slightly larger brains than women, but no one suggests that’s any correlation to actual intelligence.
In composition, a whole human brain is almost 80 percent water, with the remainder made up of lipids, proteins, carbohydrates, soluble organic substances and inorganic salts.
So the natural presumption might be that, say, boiling a brain would render it, well, non-existent. Wouldn’t it just dissolve? Not necessarily.
The image above depicts one of four brains found in human skeletons unearthed from a 4,000-year-old Bronze Age burial mound near the city of Kutahya in western Turkey. The bodies had been burned and buried (possibly victims of a long-ago earthquake and fire), but circumstances and chemistry strangely preserved the brains.
The New Scientist explained:
“The flames would have consumed any oxygen in the rubble and boiled the brains in their own fluids. The resulting lack of moisture and oxygen in the environment helped prevent tissue breakdown.”
Soil chemistry also helped. Potassium, magnesium and aluminum in the dirt reacted with fatty acids in brain tissue to help maintain the brains’ original shapes.
You can dig further into the story here.
The awe of similars
Nature is famously conservative. If it does something right, it repeats the plan.
Sometimes, technology reveals less obvious or unseen similarities. More fanciful, perhaps, but stunning nonetheless. Above are two images: One is a bright-field micrograph of a meadow buttercup floral bud, taken by Stephen S. Nagy, an honorable mention winner in the 2006 Nikon Small World microscopy contest. The other is a multi-photon fluorescence micrograph depicting intestinal villi of a mouse, taken by Thomas Deerinck at the National Center for Microscopy and Imaging Research, which took 8th place in Nikon’s 2005 contest.
Which is which? Answer below.
Answer: Flower bud top; intestine below.
Image courtesy of Mariela Loschi, Nikon Small World photomicrography competition
If you guessed nest…
Nature is famously misleading. Think, for example, about all of those insects whose camouflage is so fantastic you’re often not sure you’re actually looking at an insect. Or fractals – those remarkable self-similar patterns found in nature at every scale, from river deltas to lightning bolts to leaves.
All of which is only a slightly misleading introduction to the image above – a confocal micrograph produced by Mariela Loschi, a Pfizer analyst based in Buenos Aires, Argentina. What looks remarkably like a robin’s egg in a nest is, in fact, a much magnified image of a cultured kidney cell from a grivet, a species of Old World monkey. The blue center is the stained nucleus of the cell. It’s surrounded by microtubules, tiny filaments of protein that help maintain the physical structure of the cell, serve as internal transport highways and are involved in fundamental processes like mitosis.
Scanning electron micrograph of pleasingly plump human red blood cells. Courtesy of Thomas Deerinck, NCMIR
Hard to swallow
The average adult has a blood volume of about 5 liters or 1.3 gallons. Red blood cells, which do the vital grunt work of shuttling oxygen throughout the body, constitute about 45 percent of whole blood, white blood cells, which are part of the immune system, make up 0.7 percent and plasma (the pale yellow liquid that keeps everything in suspension) measures in at 54.3 percent.
Altogether, blood accounts for about 7 percent of human body weight.
But maybe not so much if you’re trying to lose weight.
Among the myriad popular how-to weight loss books on the market at the moment is Peter D’Adamo’s best-selling Eat Right for Your Type, in which he posits that an individual’s nutritional needs vary according to one of the four blood-types: A, B, AB or O.
According to D’Adamo, a naturopathic physician and director of the Center of Excellence in Generative Medicine at the University of Bridgeport in Connecticut, adhering to a diet that matches a specific, evolved blood type can improve health and reduce the risk of chronic disease. D’Adamo’s book has sold more than 7 million copies.
It did not, however, sell researchers at the University of Toronto who found no evidence that the blood-type/diet link was grounded in empirical evidence.
Writing in PLOS ONE, the researchers examined data from 1,455 study participants who provided detailed information about their usual diets and provided blood samples to assess various health risk factors, such as levels of cholesterol, insulin and triglycerides. Diet scores were calculated based upon the book’s guidelines.
The conclusion: Certain “blood-type” diets were associated with favorable effects on some risk factors, but the associations were independent of the person’s blood type. Study author Ahmed El-Sohemy didn’t outright dismiss the possible efficacy of the blood-type diet.
But he did note: “There was just no evidence, one way or the other. It was an intriguing hypothesis so we felt we should put it to the test. We can now be confident in saying that the blood-type diet hypothesis is false.”
Another diet bites scientific dust.
The reclusive worms are rarely seen, poking out their tentacled heads only to grab at passing bits of food or grains of sand, duly sorted for future construction and repair.
It’s the worm’s constructive capabilities that have recently earned it new headlines. Or more specifically, it’s the glue they use, which works remarkably well underwater.
In 2005, researchers at UC Santa Barbara reported that the worm glue was composed of specific proteins with opposite charges called polyphenolic proteins. Four years later, scientists at the University of Utah announced they had managed to synthesize it.
The biomedical applications were – and remain – immediately obvious. Such a glue could become an effective, new bioadhesive, used to repair broken bones or seal back together delicate tissues in the very watery environment of the human body.
Not surprisingly, there have been lots of challenges to creating an effective, real-world product, but researchers at Brigham and Women’s Hospital in Boston may be getting closer, as described in a recent NPR story using the worm-inspired glue to patch holes in pigs’ hearts.
The colon is the last part of your digestive system, charged with extracting water and salts from solid wastes at the end of the gastrointestinal line. It’s not a pretty job – a lot of bacterial-aided fermentation occurs there – but it’s essential.
To do the job right and regularly requires a fair amount of lubrication. That’s the responsibility of colonic crypts – mucus-producing intestinal glands that keep things moving along.
In this cross-sectional confocal micrograph by Michela Schaeppi of Wellcome Images, yellow cells that produce mucin are shown inside the hexagonal-shaped crypts. The white spots at the centers are crypt lumen where mucus is excreted into the colon. The blue staining indicates pericryptal sheaths.
Hate to burst your bubble
For years, the antibacterial soap industry as asserted their products kill bacteria and other pathogens more effectively than plain soap and water, that they’re much, much better at preventing illness and the spread of infections over the long haul.
Now the Food and Drug Administration is asking manufacturers to prove it.
This isn’t just another case of concerns about commercial hyperbole. An increasing number of scientists and public health groups fear the antibiotics used in these soaps are promoting resistance in the targeted microbes. Rising antibiotic resistance, however, is just part of the problem. A number of studies have shown that triclosan – a common antibacterial agent in these soaps – may interfere with human hormone activity.
The FDA action follows another bit of recent research news about personal hygiene: Washing your hands in hot water apparently offers no more hygienic benefit than using room temperature water.
A recent Vanderbilt University study found that hot water did not measurably improve the efficacy of the typical hand-washing experience.
“It is true that heat kills bacteria,” said study author Amanda Carrico. “However, the level of heat required to neutralize pathogens is beyond what is considered safe for prolonged human contact.”
The researchers noted too a downside to using all of that hot water to wash our collective hands to no great effect: It requires a lot of energy and significantly adds to greenhouse gas emissions worldwide.
They estimated that if Americans en mass used tepid water instead of warm or hot, the avoided energy use and prevented greenhouse gas emissions would be equivalent to the entire output of a nation the size of Barbados.