Today, Scientists Working With Telescopes At The European Southern Observatory And NASA Announced A Remarkable

More ‪#‎WorldChocolateDay‬ chemistry: this time with C&EN, looking at dark chocolate, milk chocolate, and white ‘chocolate’: ow.ly/ugB93021z64

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IN THE MIX

Matti Koivisto, an undergraduate student working in the laboratory of Kari Haajanen at Turku University of Applied Sciences, designs solutions similar to this one to detect the bacteria Escherichia coli. He uses a dye called rhodamine 6G, which has a strong orange color when dissolved in ethanol. In solution, the dye separates into negatively and positively charged ions, the latter of which are largely responsible for the dye’s color. Negatively charged molecules on the outer membranes of E. coli attract the dye’s positive ions. This interaction causes the dye to change color to a pinkish hue, and the level of color change allows Koivisto to gauge how many of the bacteria are present.

Submitted by Matti Koivisto

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Related C&EN content:

How dyes in mouse feces help track insects

Using an ink-jet printer to simplify analytical chemistry

Finally got the pure Nile Red in solution, just need to evaporate to get the pure dye.

Interesting fact: Nile Red is a solvatochromic dye. What does this mean? Solvatochromism is the ability of a chemical substance to change color due to a change in solvent polarity, so it has different color in different solvents. Also its emission and excitation wavelength both shift depending on solvent polarity, so it fluoresces with with different color depending on the solvent what it’s dissolved in. 

In this case it was dissolved in dichloromethane.

Today is the Autumn Equinox in the northern hemisphere! What’s behind the changing colours of autumn leaves? http://wp.me/p4aPLT-sn

“Sixth sense” may be more than just a feeling

With the help of two young patients with a unique neurological disorder, an initial study by scientists at the National Institutes of Health suggests that a gene called PIEZO2 controls specific aspects of human touch and proprioception, a “sixth sense” describing awareness of one’s body in space. Mutations in the gene caused the two to have movement and balance problems and the loss of some forms of touch. Despite their difficulties, they both appeared to cope with these challenges by relying heavily on vision and other senses.

“Our study highlights the critical importance of PIEZO2 and the senses it controls in our daily lives,” said Carsten G. Bönnemann, M.D., senior investigator at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and a co-leader of the study published in the New England Journal of Medicine. “The results establish that PIEZO2 is a touch and proprioception gene in humans. Understanding its role in these senses may provide clues to a variety of neurological disorders.”

Dr. Bönnemann’s team uses cutting edge genetic techniques to help diagnose children around the world who have disorders that are difficult to characterize. The two patients in this study are unrelated, one nine and the other 19 years old. They have difficulties walking; hip, finger and foot deformities; and abnormally curved spines diagnosed as progressive scoliosis.

Working with the laboratory of Alexander T. Chesler, Ph.D., investigator at NIH’s National Center for Complementary and Integrative Health (NCCIH), the researchers discovered that the patients have mutations in the PIEZO2 gene that appear to block the normal production or activity of Piezo2 proteins in their cells. Piezo2 is what scientists call a mechanosensitive protein because it generates electrical nerve signals in response to changes in cell shape, such as when skin cells and neurons of the hand are pressed against a table. Studies in mice suggest that Piezo2 is found in the neurons that control touch and proprioception.

“As someone who studies Piezo2 in mice, working with these patients was humbling,” said Dr. Chesler. “Our results suggest they are touch-blind. The patient’s version of Piezo2 may not work, so their neurons cannot detect touch or limb movements.”

Further examinations at the NIH Clinical Center suggested the young patients lack body awareness. Blindfolding them made walking extremely difficult, causing them to stagger and stumble from side to side while assistants prevented them from falling. When the researchers compared the two patients with unaffected volunteers, they found that blindfolding the young patients made it harder for them to reliably reach for an object in front of their faces than it was for the volunteers. Without looking, the patients could not guess the direction their joints were being moved as well as the control subjects could.

The patients were also less sensitive to certain forms of touch. They could not feel vibrations from a buzzing tuning fork as well as the control subjects could. Nor could they tell the difference between one or two small ends of a caliper pressed firmly against their palms. Brain scans of one patient showed no response when the palm of her hand was brushed.

Nevertheless, the patients could feel other forms of touch. Stroking or brushing hairy skin is normally perceived as pleasant. Although they both felt the brushing of hairy skin, one claimed it felt prickly instead of the pleasant sensation reported by unaffected volunteers. Brain scans showed different activity patterns in response to brushing between unaffected volunteers and the patient who felt prickliness.

Despite these differences, the patients’ nervous systems appeared to be developing normally. They were able to feel pain, itch, and temperature normally; the nerves in their limbs conducted electricity rapidly; and their brains and cognitive abilities were similar to the control subjects of their age.

“What’s remarkable about these patients is how much their nervous systems compensate for their lack of touch and body awareness,” said Dr. Bönnemann. “It suggests the nervous system may have several alternate pathways that we can tap into when designing new therapies.”

Previous studies found that mutations in PIEZO2 may have various effects on the Piezo2 protein that may result in genetic musculoskeletal disorders, including distal arthrogryposis type 5, Gordon Syndrome, and Marden-Walker Syndrome. Drs. Bönnemann and Chesler concluded that the scoliosis and joint problems of the patients in this study suggest that Piezo2 is either directly required for the normal growth and alignment of the skeletal system or that touch and proprioception indirectly guide skeletal development.

“Our study demonstrates that bench and bedside research are connected by a two-way street,” said Dr. Chesler. “Results from basic laboratory research guided our examination of the children. Now we can take that knowledge back to the lab and use it to design future experiments investigating the role of PIEZO2 in nervous system and musculoskeletal development.”

Neuroscientists’ Study Sheds Light on How Words Are Represented in the Brain

Reading is a relatively modern and uniquely human skill. For this reason, visual word recognition has been a puzzle for neuroscientists because the neural systems responsible for reading could not have evolved for this purpose. “The existence of brain regions dedicated to reading has been fiercely debated for almost 200 years,” said Avniel Ghuman, an assistant professor in the University of Pittsburgh Department of Neurological Surgery. “Wernicke, Dejerine, and Charcot, among the most important and influential neurologists and neuroscientists of the 19th century, debated whether or not there was a visual center for words in the brain.”

In recent years, much of this debate has centered on the left mid-fusiform gyrus, which some call the visual word form area. A recent study by Pitt neuroscience researchers addresses this debate and sheds light on our understanding of the neurobiology of reading.

In a study published July 19 in the Proceedings of the National Academy of Sciences, Ghuman, Elizabeth Hirshorn of Pitt’s Learning Research and Development Center (LRDC), and colleagues from the Department of Psychology and Center for the Neural Basis of Cognition used direct neural recordings and brain stimulation to study the role of the visual word form area in reading in four epileptic patients. The patients chose surgical treatment for their drug-resistant epilepsy and volunteered to participate in the research study. As part of the surgical treatment, neurosurgeons implanted electrodes in the patients’ visual word form area, providing an unprecedented opportunity to understand how the brain recognizes printed words.

First, painless electrical brain stimulation was used through the electrodes to disrupt the normal functioning of the visual word form area, which adversely affected the patients’ ability to read words. One patient dramatically misperceived letters, and another felt that there were words and parts of words present that were not in what she was reading. Stimulation to this region did not disrupt their ability to name objects or faces. A brief video of the stimulation can be seen here.

In addition to stimulating through these electrodes, the activity from the area was recorded while the patients read words. Using techniques from machine learning to analyze the brain activity that evolved over a few hundred milliseconds from this region, the researchers could tell what word a patient was reading at a particular moment. This suggests that neural activity in the area codes knowledge about learned visual words that can be used to discriminate even words that are only one letter different from one another (for example, “hint” and “lint”).

“This study shows that the visual word form area is exquisitely tuned to the fine details of written words and that this area plays a critical role in refining the brain’s representation of what we are reading. The disrupted word and letter perception seen with stimulation provides direct evidence that the visual word form area plays a dedicated role in skilled reading,” said Hirshorn. “These results also have important implications for understanding and treating reading disorders. The activity in the visual word form area, along with its interactions with other brain areas involved in language processing, could be a marker for proficient reading. Having a better understanding of this neural system could be critical for diagnosing reading disorders and developing targeted therapies.”

“It is exciting that with modern brain-recording techniques and advanced analysis methods, we are finally able to start answering questions about the brain and the mind that people have asked for centuries and contribute to our understanding of reading disorders,” said Ghuman.

R.I.P. Dr. Vera Rubin

As I write this, reports are spreading rapidly through the astronomy community of the death of Dr. Vera Rubin on December 25, 2016. If you don’t know who she was, or what she worked on, come sit by me and let me tell you a story about this lady.

It was at one of the first meetings of the American Astronomical Society I attended. I was a graduate student and giving a talk about outreach and amateur astronomy. I was scared to death because, hey, it was me, a lowly student giving a talk to all these exalted astronomers. A woman sat in the front row and smiled at me as I shuffled the papers on the podium. The room filled and then the session chair gave me the signal that my 10 minutes had started. I plunged into my talk.

At the end, a few people asked questions, everyone clapped politely, and the next person stepped up to the podium. I fled the room to catch my breath. The woman followed me out and asked if I’d like to get a cup of coffee. At the same moment my advisor came out and said, “Oh, I see you’ve met Vera Rubin”, and he proceeded to introduce me to her before being collared by someone else for a chat. Dr. Rubin and I went to get coffee, and for the next 30 minutes or so she asked me all about my work and what I hoped to do when I graduated. It was a wonderful experience.

Over the years we met here and there, and I learned more about her work with galaxy rotation studies and the existence of dark matter. I found it fascinating, as so many people do, and followed her research with interest. When I was asked to write a book about astronomy, one of the directions I got from the editors was to include some bios of “seminal” astronomers. Dr. Rubin was one of those I chose. In retrospect, I wish could have done a book on her work instead of simply a chapter.

I know that Vera Rubin didn’t work in a vacuum on dark matter — that, like Newton and every other astronomer has done — she stood on the shoulders of giants. Her work forged a new path in understanding dark matter and its affect on the universe. Now, she is a giant in her own right. Now, others will stand on her shoulders. Her insights and drive to understand the difficult “galaxy rotation problem” led directly to the theory of dark matter, and more recently to the confirming observations of its existence. It was a monumental achievement.

For her work, Dr. Rubin should have received a Nobel Prize. That didn’t happen and the Nobel physics committee should be thinking hard about why she was overlooked. She has been honored with many other prizes and awards for her insights, and she will be long remembered for her seminal contributions to astronomy.

RIP Dr. Vera Rubin, and deepest condolences to her extended family.

C.C. PETERSEN is a science writer and media producer specializing in astronomy and space science content. 

Source: The Spacewriter

This Week in Chemistry: Preventing marble statue weathering, further progress towards hydrogen fusion, and more! Links: http://goo.gl/WeJRV5

Today is World Blood Donor Day – here’s a look at some blood chemistry! More info/high-res image: http://wp.me/s4aPLT-blood