1. Putting a New Twist on Speciation: Campylobacter Cells Reunite At Last
C. jejuni and C. coli are microaerophilic bacteria that have a characteristic corkscrew shape. Both belong to the same genus, Campylobacter (which means “twisted bacteria”). They are the foodborne pathogens responsible for the campylobacteriosis infection, which can cause periodontitis, dysentery, and inflammatory diarrhea.
Scientists recently discovered that C. jejuni and C. coli are beginning to merge into one species through a process called hybridization. Though they share about 85 percent of their genetic code, the two species have traditionally been very different, having adapted to fill specific niches inside the guts of chicken, cows, and other livestock.
But because of industrialized farming—which involves keeping livestock in ultra-close proximity—C. jejuni and C. coli have been pushed closer together, facilitating the exchange of genes through a process called hybridization.
This false-color electron-microscope image shows Campylobacter cells clumping together.
2. High-Tailing It: Listeria Moving Through a Cell
Listeria monocytogenes, a rod-shaped bacterium, is one of the world’s deadliest foodborne pathogens. It causes listeriosis, a group of life-threatening diseases that include meningitis, encephalitis, pneumonia, septicemia, and intrauterine or cervical infections in pregnant women. The latter account for around 27 percent of the 500 listeria deaths that occur in the U.S. every year.
L. monocytogenes infects and moves through white blood cells using actin rockets, also known as “comet tails.” The rockets work like this: A protein anchored to the bacterium’s membrane triggers the rapid polymerization of the protein actin; this provides an explosive boost, so the bacterium can push through the membrane of white blood cells and burst out to infect another cell.
In this image, the bacteria (shown in red) are traveling around a cell using their bright actin rockets.
3. The Pretty Invasion: Endothelial Cells Infected by Cytomegalovirus
More commonly known as human herpesvirus 5 or HCMV, cytomegalovirus is the most frequently transmitted intrauterine infection and can result in serious disabilities at birth, though most people will exhibit only mild symptoms or none at all.
About 1 in 150 children is born with congenital CMV, and 1 in 750 children suffers from permanent disabilities due to the infection. This multicolor immunofluorescence image shows human endothelial cells being infected by cytomegalovirus.
4. Microcellular Warfare: When Neutrophils Attack
Streptococcus pyogenes, a spherical bacteria that typically grows in long chains, can cause minor infections like impetigo to potentially deadly diseases like streptococcal toxic shock syndrome. The cells possess a number of defense mechanisms, known as virulence factors, which allow them to evade the host’s immune system and spread through its tissues.
In this image, human neutrophils—white blood cells that are one of the body’s first lines of defense—are engulfing S. pyogenes cells through a process known as phagocytosis.
M I Walker, Wellcome Images
This striking image actually shows part of an ox’s eye, and the capillaries in it. Capillaries are small blood vessels, which act as the connective network between arteries and veins. The capillaries have been made visible by injection of an insoluble dye into the artery that supplied them.
Top Ten Myths About the Brain
When it comes to this complex, mysterious, fascinating organ, what do—and don’t—we know?
By Laura Helmuth
1. We use only 10 percent of our brains.
This one sounds so compelling—a precise number, repeated in pop culture for a century, implying that we have huge reserves of untapped mental powers. But the supposedly unused 90 percent of the brain is not some vestigial appendix. Brains are expensive—it takes a lot of energy to build brains during fetal and childhood development and maintain them in adults. Evolutionarily, it would make no sense to carry around surplus brain tissue. Experiments using PET or fMRI scans show that much of the brain is engaged even during simple tasks, and injury to even a small bit of brain can have profound consequences for language, sensory perception, movement or emotion.
2. “Flashbulb memories” are precise, detailed and persistent.
We all have memories that feel as vivid and accurate as a snapshot, usually of some shocking, dramatic event—the assassination of President Kennedy, the explosion of the space shuttle Challenger, the attacks of September 11, 2001. People remember exactly where they were, what they were doing, who they were with, what they saw or heard. But several clever experiments have tested people’s memory immediately after a tragedy and again several months or years later.
3. It’s all downhill after 40 (or 50 or 60 or 70).
It’s true, some cognitive skills do decline as you get older. Children are better at learning new languages than adults—and never play a game of concentration against a 10-year-old unless you’re prepared to be humiliated. Young adults are faster than older adults to judge whether two objects are the same or different; they can more easily memorize a list of random words, and they are faster to count backward by sevens.
But plenty of mental skills improve with age. Vocabulary, for instance—older people know more words and understand subtle linguistic distinctions. Given a biographical sketch of a stranger, they’re better judges of character. They score higher on tests of social wisdom, such as how to settle a conflict. And people get better and better over time at regulating their own emotions and finding meaning in their lives.
4. We have five senses.
Sure, sight, smell, hearing, taste and touch are the big ones. But we have many other ways of sensing the world and our place in it. Proprioception is a sense of how our bodies are positioned. Nociception is a sense of pain. We also have a sense of balance—the inner ear is to this sense as the eye is to vision—as well as a sense of body temperature, acceleration and the passage of time.
5. Brains are like computers.
We speak of the brain’s processing speed, its storage capacity, its parallel circuits, inputs and outputs. The metaphor fails at pretty much every level: the brain doesn’t have a set memory capacity that is waiting to be filled up; it doesn’t perform computations in the way a computer does; and even basic visual perception isn’t a passive receiving of inputs because we actively interpret, anticipate and pay attention to different elements of the visual world.
6. The brain is hard-wired.
This is one of the most enduring legacies of the old “brains are electrical circuits” metaphor.
But one of the biggest discoveries in neuroscience in the past few decades is that the brain is remarkably plastic. In blind people, parts of the brain that normally process sight are instead devoted to hearing. Someone practicing a new skill, like learning to play the violin, “rewires” parts of the brain that are responsible for fine motor control. People with brain injuries can recruit other parts of the brain to compensate for the lost tissue.
7. A conk on the head can cause amnesia.
Next to babies switched at birth, this is a favorite trope of soap operas: Someone is in a tragic accident and wakes up in the hospital unable to recognize loved ones or remember his or her own name or history. (The only cure for this form of amnesia, of course, is another conk on the head.)
8. We know what will make us happy.
In some cases we haven’t a clue. We routinely overestimate how happy something will make us, whether it’s a birthday, free pizza, a new car, a victory for our favorite sports team or political candidate, winning the lottery or raising children. Money does make people happier, but only to a point—poor people are less happy than the middle class, but the middle class are just as happy as the rich. We overestimate the pleasures of solitude and leisure and underestimate how much happiness we get from social relationships.
9. We see the world as it is.
We are not passive recipients of external information that enters our brain through our sensory organs. Instead, we actively search for patterns (like a Dalmatian dog that suddenly appears in a field of black and white dots), turn ambiguous scenes into ones that fit our expectations (it’s a vase; it’s a face) and completely miss details we aren’t expecting. In one famous psychology experiment, about half of all viewers told to count the number of times a group of people pass a basketball do not notice that a guy in a gorilla suit is hulking around among the ball-throwers.
10. Men are from Mars, women are from Venus.
Some of the sloppiest, shoddiest, most biased, least reproducible, worst designed and most overinterpreted research in the history of science purports to provide biological explanations for differences between men and women. Eminent neuroscientists once claimed that head size, spinal ganglia or brain stem structures were responsible for women’s inability to think creatively, vote logically or practice medicine. Today the theories are a bit more sophisticated: men supposedly have more specialized brain hemispheres, women more elaborate emotion circuits. Though there are some differences (minor and uncorrelated with any particular ability) between male and female brains, the main problem with looking for correlations with behavior is that sex differences in cognition are massively exaggerated.
In the image: Bryan Ballif, University of Vermont Bryan Ballif, a University of Vermont biologist, in front of his mass spectrometer. Joshua Brown, University of Vermont, 2012
Researchers at the University of Vermont have discovered two new proteins on red blood cells that confirm the testable existence of two new blood types. It’s an important discovery, one that’ll greatly reduce the risk of incompatible blood transfusions among tens of thousands of people. But what we were more struck by in this press release was the fact that these two new blood types—named Junior and Langereis—bring the total number of recognized blood types up to 32. 32!
Turns out there’s much more than just A, B, AB, and O: there are now 28 other, rarer types, often named after the person in whom they were discovered. These rarer types are identified by the presence of a particular group of antigens (substances that tell your immune system to send out antibodies), and many, like the Kell and MNS blood types, can actually be concurrent with more common blood types like A or O.
But the discovery of new blood types is pretty rare; the last new one was discovered more than a decade ago. So it’s big news that two were discovered at the same time. The Junior and Langereis groups are particularly prevalent in East Asia, especially Japan. Says University of Vermont biologist Bryan Ballif: “More than 50,000 Japanese are thought to be Junior negative and may encounter blood transfusion problems or mother-fetus incompatibility.”
The study appears in the February issue of Nature Genetics.
20 Things You Didn’t Know About Sugar
We eat it, we love it, and it may have been a chemical precursor to life on Earth.
sucrose, the most common free sugar.Magnification of grains of refined
1 The average American eats 61 pounds of refined sugar each year, including 25 pounds of candy. Halloween accounts for at least two pounds of that.
2 Trick: Sugar may give you wrinkles via a process called glycation, in which excess blood sugar binds to collagen in the skin, making it less elastic.
3 Or treat: Cutting back on sugar may help your skin retain its flexibility. So actually, no treats.
4 People in India have been crystallizing cane sugar for at least 2,000 years. When Alexander the Great’s companions arrived there, they marveled at the production of honey without bees.
5 In 1747 German chemist Andreas Marggraf discovered that the sugar in a sugar beet is identical to that in sugarcane. In 1802 the first beet-sugar refinery began operations, bringing cheap sweets to northern climes.
6 More than half the 8.4 million metric tons of sugar produced annually in the United States comes from beets.
7 Can you imagine eating 16 sugar cubes at one sitting? You probably have. That’s a little less than what is contained in a 20-ounce bottle of cola.
8 Soft drinks with artificial sweeteners may actually help make you fat. In a Purdue University study, rats drinking liquids with artificial sweeteners consumed more calories overall than rats whose drinks were sweetened with sugar.
9 The artificial sweeteners saccharin and aspartame were found accidentally when lab workers doing research that had nothing to do with sweetening put a bit of the test compounds in their mouths and liked what they tasted.
10 What kind of researcher sticks an experiment in his mouth?
11 At least he had an excuse. The scientists who discovered sucralose (now sold as Splenda) were originally trying to create an insecticide. An assistant thought he had been instructed to “taste” a compound he’d only been asked to “test.”
12 A compound called lugduname is the sweetest compound known—more than 200,000 times as sweet as table sugar.
13 Sugars are molecules of carbon, hydrogen, and oxygen. The simplest include glucose, fructose, and galactose. Table sugar is crystallized sucrose, a fusion of one fructose and one glucose molecule.
14 Can’t escape them: Sugars are the building blocks of carbohydrates, the most abundant type of organic molecules in living things.
15 Glycolaldehyde, an eight-atom sugar, has even been found in an interstellar gas cloud near the center of the Milky Way.
16 Glycolaldehyde can react with a three-carbon sugar to form ribose, the basis for both RNA and DNA, so the glycolaldehyde found in deep space may be a chemical precursor to life on Earth.
17 That cloud also contains ethylene glycol, a sweet relative of glycolaldehyde and the main ingredient in antifreeze. Either complex sugars can be synthesized between the stars or there is a truck stop at the end of the universe.
18 Sugar can help get you there to find out. Burn sucrose with a dose of corn syrup and saltpeter and you get “sugar propellant,” a popular amateur rocket fuel.
19 How do you spell relief? “Obecalp,” a sugar pill manufactured to FDA standards, is marketed as a treatment for children’s mild complaints. (Try reading the name backward.)
20 It’s not all mind games. The sugar glucosamine works as an immunosuppressant in mice, and xylitol (a sugar alcohol) can prevent ear infections in kids. Sweet!
Scientists Can Now Actually Read Your Mind
In a series of new experiments, scientists have been able to use a computer to decipher brain activity. So what, huh? Well, the computer can reconstruct those signals into the actual words the participants are thinking about. It can read your mind.
OK, so sometimes the words were difficult to recognise, but that’s not the point: it means that people unable to speak could generate a voice just by thinking in sentences.
“Potentially, the technique could be used to develop an implantable prosthetic device to aid speaking, and for some patients that would be wonderful,” Robert Knight, a senior member of the team and director of the Helen Wills Neuroscience Institute at the University of California, Berkeley, told the Guardian. “Perhaps in 10 years it will be as common as grandmother getting a new hip.”
The experiment involved 15 patients having the top of their skull removed — don’t worry, they were already having surgery that required that — and having a net of electrodes laid across the surface of their brain.
The patients were then played a series of words for five to ten minutes while having their brain activity recorded. Software was then used to decode the brain signals and reconstruct the words. The research is published in PLoS Biology.
For now, reading someone’s mind like this is an invasive process requiring access to the brain, but that’s not to say it always will be. The idea of creating a device that could help give people a voice would surely cause some headaches, not least the problem of filtering private thoughts from information to be communicated. But scientists love a challenge. [PLoS Biology andThe Guardian; Image: dierk schaefer]
Republished from http://gizmodo.com
June 15, 1667: First Human Blood Transfusion Is Performed
1667: The first blood transfusion involving a human being is performed.
Jean-Baptiste Denys, personal physician to France’s Louis XIV, is generally credited with performing the first human blood transfusion, although some sources award that distinction to Englishman Richard Lower. What is not in dispute is the year — 1667 — and the patient — a 15-year-old boy who had been bled so much by his doctor that he required an infusion of blood.
The source is also not under dispute: Whoever the physician was, he used a sheep’s blood. And, somehow, the kid recovered.
Subsequent transfusions using sheep’s blood were not as successful, however, and the practice was eventually banned. Science was unaware of the danger not only of interspecies transfusions but of the fact that human beings possessed different, generally incompatible, blood types.
The four major blood groups were not identified until the first decade of the 20th century.
Another discovery that advanced the science of blood transfusions occurred in 1901, when Viennese physician Karl Landsteiner demonstrated the presence of agglutinins and iso-agglutinins in the blood. Landsteiner’s work earned him a Nobel Prize.
Image: Valentina Petrova/AP
This article first appeared on Wired.com June 15, 2007.
The pharmaceutical industry spends untold millions of dollars trying to discover the next wonder drug. The potential profits from a breakthrough drug can be counted in the billions of dollars — and a great new medication can improve the lives of countless people. But sometimes the greatest breakthroughs in drug development come from the weirdest sources. Here are 10 drugs that started their lives as poisons, road coverings, or as treatments for very different maladies.
Rogaine (Minoxidil) first came to market as Loniten, a drug used to treat high blood pressure. Users observed an interesting side effect — Loniten increased the darkness of hair and caused hair growth. The Upjohn Corporation soon produced a decreased strength version to be sold over the counter for direct application to the scalp. One of the downsides of Rogaine is the need for continued application to prevent hair loss, but it’s not banned by the International Olympic Committee like another anti-baldness drug.
9. Pink Bismuth
Bismuth is an element, so it did not follow the typical drug development scheme. The heavy metal is of little apparent use, but is known for its extremely low thermal conductivity and low human toxicity. Bismuth’s pharmaceutical application comes through the consumption of Bismuth subsalicylate, the active ingredient in the anti-diarrheals Pink Bismuth (better known as Pepto-Bismol) and Kaopectate. The element is also used in the form of Bismuth subgallate, a component of the internal deodorant Devrom, an over the counter medication for preemptive removal of fecal odor. If you ever have a blow torch and some Pepto-Bismol around, you can recover the solid bismuth oxide slag if you are ever bored enough and like fire.
8. Botulinum toxin
Botulinum is the most powerful neurotoxin known to humanity, but for some reason, people started injecting the protein into their foreheads to stop eyelid twitching and cosmetically to paralyze muscles in the forehead to alleviate frown lines in 1989.
Finasteride, better known as Proscar or Propecia, is a molecule initially used for treatment of an enlarged prostate. Like Loniten, an interesting side effect occurred with finasteride users, as long-term use resulting in a decrease in male pattern baldness.
6. Coal tar
A brownish black liquid left over from the use of coal as fuel, coal tar contains a plethora of hydrocarbons and is traditionally used to pave roads or prevent lice infestation and dandruff when added to shampoos.
The single most important discovery on this list, and one I’m sure most of you are familiar with. Alexander Fleming is noted for discovering that Penicillium chrysogenum, a blue-green fungi that loves damp environments, secretes a substance with antibacterial properties when grown in the right situation. A stray spore of mold landed landed on a bacteria culture used in Fleming’s research, leading to his keen observation.
4. Acetylsalicylic acid
Hippocrates wrote that an extract from the bark of the willow tree relieved pain and quelled fevers, with several cultures, including Native Americans, independently determining the special attributes of the bark. The active ingredient in the willow tree bark, salicylic acid, is a plant hormone playing roles in photosynthesis and plant growth.
Your dad or grandmother probably takes Warfarin (also known as Coumadin) to prevent blood clots, going in to check their INR readings every couple of weeks. The same thing your relatives take as a preventive measure to extend their lives started out as a quick and dirty way to kill rats.
Sildenafil citrate, also know as the scourge of retirement homes or Viagra in some circles, began as compound UK-92,480, reaching phase 1 clinical trials for treatment of hypertension and angina. Sildenafil citrate didn’t perform well in trials to treat either malady, but molecule did give patients erections.
1. Nitrogen Mustards
Release of mustard gas on citizens of Italy during World War II decreased the number of lymphocytes in exposed individuals. Clinical trials underway at the same time in secret at Yale University used nitrogen mustard to combat cancer. Bis(2-chloroethyl)methylamine (better known as the chemical warfare agent HN2) is one of the best known nitrogen mustards, with HN2 becoming the first anticancer chemotherapy drug.
Messenger RNA Discovery: “Biology’s Most Important Molecule” —Built-in ‘Clock’ Causes Its Ultimate Death
“The fate of the mRNA molecules we studied resembles a Greek tragedy,” said Robert Singer, Ph.D., co-director of the Gruss Lipper Biophotonics Center and professor and co-chair of anatomy and structural biology at Einstein College of Medicine. “Their lifespans are determined at the moment of their birth.”