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How Green Fluorescent Proteins Bioluminesce: “
Berkeley researchers have identified the mechanism that makes green fluorescent protein (GFP) light up the way it does. They used femtosecond lasers to image the molecules as they undergo structural changes that cause them to fluoresce.
The transfer of a positively-charged hydrogen atom – a bare proton – along a reaction chain in GFP generates a green flash of light. The laser snapshots show that when the light absorber, or chromophore, nestled in the middle of the protein barrel absorbs an incoming photon of blue light, it starts vibrating, and the electrons start sloshing around the chromophore until it is aligned just right for the proton to hop via a water molecule to a nearby amino acid in the protein. From there, it continues down the reaction chain, creating a state with a negatively charged chromophore that emits green light.
Previous studies had shown that after the chromophore absorbs blue light, it undergoes proton transfer, and green light is emitted. In the current study, Mathies, Fang and their colleagues could actually resolve the early stage of this proton transfer reaction, taking snapshots of the vibrational wagging of the chromophore skeleton in sync with the electron cloud in the chromophore sloshing back and forth. However, the wagging oscillation might have stopped after a few picoseconds, when the chromophore and its vicinity are aligned just right for the proton to hop off down the reaction chain, and the whole protein shines bright green – which it does in its own good time, in about 3 nanoseconds.
Femtosecond stimulated Raman spectroscopy on GFP involves hitting the protein molecule with an approximately 80 femtosecond pulse of ultraviolet light, which excites many vibrational modes in the molecule, and then a one-two punch of picosecond red and femtosecond white light to stimulate Raman emission. The spectrum of emitted signals tells researchers the vibrational modes of various parts of the molecule. If the molecule is in the middle of a reaction, the emitted light at different time delays tells the researcher the various steps the molecule goes through during the reaction.
Berkeley Lab press release: Vibrations key to efficiency of green fluorescent protein …
Abstract in Nature: Mapping GFP structure evolution during proton transfer with femtosecond Raman spectroscopy
(Via Medgadget.)
2 Online Guides to Check Your Illness Symptoms Online: “
There are times when we want to check certain illness symptoms we or our loved ones are experiencing. We may not be sure if the symptoms warrant further investigation or we might just want to satisfy our curiosity about health and fitness in general.
In this article, let us look at two online guides to check your illness symptoms online, which are extremely easy to use and provide information about probable causes.
Before we proceed, it is necessary to stress that these guides should not be used as a substitute for professional medical advice. It is better that you use these tools as a supplementary resource to get more information, while you may be waiting for your doctor’s appointment, or to learn more about certain illnesses.
Check Symptoms Online With WebMD Symptom Checker
Web MD Symptom Checker is an easy to use interactive tool, where you select specific symptoms and it identifies possible causes.
You start by selecting your gender and age, after which you can specify the symptoms in three ways in the left panel:
- You can identify the symptom by zooming in on the affected body part in the interactive map of the human body on the left.
- You can select from a list of 76 possible symptoms organized in an alphabetical list and a common symptoms list.
- You can search for symptoms using the search box.
If applicable, you can select and add more symptoms. Once you identify the symptoms, the Symptom Checker shows you a list of possible conditions that may be the cause of them. You can check more about any possible condition right within the Symptom Checker.
For each condition, Symptom Checker provides you with an overview, a list of all symptoms associated with that condition, and related articles and videos on the WebMD website.
Mayo Clinic Symptom Checker
Use this guide to discover the most common causes of the most common symptoms. The Mayo Clinic Symptom Checker takes a different approach to isolating possible conditions than the WebMD version.
You first select between Adult and Child symptoms on the first page. For Adults, there are 28 common symptoms listed. After you choose one kind of symptom, the next page lets you select related factors depending upon the selected symptom:
- Details such as persistent/intermittent, started suddenly/gradually, etc.
- Whether it affects both pairs of hands/legs/etc.
- Details of the pain – duration, pattern, severity, location
- Trigger factors such as injury, repetitive use, stress, change in sleeping pattern, etc.
- Relieving factors such as medication, rest
- Accompanying symptoms associated with the selected symptom
Note that this page is specific and different for each of the 28 symptoms listed in the first page. The questions on this page are similar to what a doctor would ask you after you tell him about a symptom. So the process actually feels similar to an actual diagnosis!
After you make the appropriate selections on this page, the next one gives you possible causes of the symptoms. Here, you can see all associated factors or symptoms related to this condition.
Clicking on the condition takes you to the main page for it on the Mayo Clinic website. Here, you will find a wealth of information and resources such as description, causes, risk factors, tests and diagnosis, treatment and drugs, home and alternative remedies, prevention, etc.
For more health-related articles, check out our health category.
Did you find these tools useful? Any other online illness guide that you prefer? Tell us in the comments!
Did you like the post? Please do share your thoughts in the comments section!
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(Via MakeUseOf.com.)
Melody Transcatheter Cardiac Valve Replacement Shows Good Results in Children: “
Cardiologists from Miami Childrens Hospital, Morgan Stanley Childrens Hospital, New York, and Childrens Hospital Boston just published preliminary results from the study of Medtronics Melody® Transcatheter Pulmonary Valve in 34 children and young adults who were implanted with the device for dysfunctional right ventricular outflow tract conduits. The early results are promising and may help the Melody valve get approved in the US as the first transcatheter cardiac valve on the market.
All patients underwent cardiac catheterization with the intention of implanting the artificial valve, and 30 of the 34 underwent actual implantation attempts, of which 29 were successful. Three patients (9 percent) had complications during implantation, but all survived.
At follow-up six months later, no patient had more than mild pulmonary regurgitation. Of 24 patients who had Class II or III heart failure (mild to moderate limitation of physical activity) before the procedure, 19 had improved by at least one functional class at six months, and no patient’s function had declined.
Eight of the 29 devices developed partial fractures during follow-up, and 3 patients required a second Melody valve (inserted inside the first one) for recurrent blockage.
Children’s Hospital Boston press statement: Catheter-delivered Valve May Help People with Heart Defects Avoid Multiple Surgeries; Medtronic statement: Melody® Transcatheter Valve Demonstrates Encouraging Results in Study on Patients with Congenital Heart Disease…
Abstract in Journal of the American College of Cardiology: Implantation of the Melody Transcatheter Pulmonary Valve in Patients With a Dysfunctional Right Ventricular Outflow Tract Conduit …
Product page: Melody® Transcatheter Pulmonary Valve and Ensemble® Transcatheter Delivery System …
Flashbacks: Medtronic’s Melody Transcatheter Pulmonary Valve on Track for Approval ; Melody Transcatheter Pulmonary Valve Still Being Tested in the US …; The Melody Valve Approved in Canada; The Melody Transcatheter Pulmonary Valve
(Via Medgadget.)
Travel Secrets of Ulcer Causing Bacteria Revealed: “
A team from Boston University, MIT, and Harvard discovered how the H. pylori bacteria penetrate the stomach mucus to cause ulcers in the lining.
H. pylori secretes the enzyme urease, which interacts with urea in the stomach to produce ammonia–the ammonia is what neutralizes the acids in the immediate environment. The less-acidic environment de-gels the mucin, allowing the microbe to travel through it using standard, flagella-based locomotion, much like other swimming bacteria.
To confirm their findings, the researchers placed H. pylori into an acidic mucin gel in a laboratory setting. While its flagella moved, the organism could not. After the microbes secreted urease and acidity diminished, the microbes were able to forge through the gel.
Bansil and her colleagues next want to understand the progress of H. pylori-related diseases, particularly in the context of living hosts. The team is planning to work on new imaging techniques that may reveal even greater detail about the organisms and how they inflict damage on the human body.
H. pylori bacterium stuck in a mucin gel at pH4. The flagella rotate but the bacterium does not move freely. But it gains motility as it increases the pH level of the mucin:
This video clip shows H. pylori bacteria moving around in a mucin solution at pH 6. The higher pH level means the mucin is less solid and allows greater movement for the bacteria:
Abstract in PNAS: Helicobacter pylori moves through mucus by reducing mucin viscoelasticity …
Read on from the National Science Foundation: How Bacteria Get Past Our Defenses …
(Via Medgadget.)
Patients Waiting for Lung Transplants May Soon Breathe a Sigh of Relief | 80beats: “
Emphysema and cystic fibrosis patients who need new lungs are faced with a life-threatening problem: more than 80 percent of donated lungs can’t be used—they’re inflamed and barely functional [Scientific American]. Transplanted lungs also fail at a much higher rate than other transplanted organs, as they’re more likely to be rejected by the recipient’s body. But a new procedure that makes use of gene therapy may soon double or triple the supply of undamaged donated lungs, and may also improve their function once transplanted.
In both pre- and post-transplant lungs, the problem is inflammation caused by insufficient amounts of an immune molecule called IL-10. Donated lungs are immediately chilled on ice, which destroys any IL-10 that may remain in the lungs, allowing substantial damage to occur before the organ can be implanted. And a lack of the molecule after transplantation increases the likelihood that inflammation will damage the organ and induce rejection [Los Angeles Times].
To get around these problems, the researchers first built a domed chamber where pig lungs were kept at body temperature with a steady flow of oxygen and nutrients moving through them. That arrangement alone prevented substantial damage to the lungs. Next, in the gene therapy stage, the researchers used a harmless virus to bring a gene that produces IL-10 into the lung cells.
Lead researcher Shaf Keshavjee explains that the lungs that received the therapy had better blood flow and were more able to take in oxygen and expel carbon dioxide, the study showed. ‘It’s as if gene therapy turbocharges each individual cell to manufacture many more proteins in its own IL-10 factory,’ Keshavjee said [Bloomberg]. The lungs also performed better and were better tolerated by the pigs who received the transplants, according to the study published in Science Translational Medicine.
The researchers also tried the first parts of the procedure on donated human lungs that were too damaged to transplant. The human lungs showed the same improvements in blood flow and respiration, suggesting that the therapy could repair lungs that would otherwise have been discarded, and could therefore increase the stock of available organs. Last year, 234 people in the U.S. died while waiting for a lung transplant…. Currently, more than 1,800 people in the U.S. are waiting for a lung [Bloomberg].
The human lungs weren’t transplanted into sick patients, but if Keshavjee’s experiments continue to go well human trials could begin in about a year. While questions about gene therapy remain–in some cases, the viral vectors used to transport genes have been found to cause serious side effects–the new approach has the potential to be a breath of fresh air.
Related Content:
80beats: Doctors Work Towards Womb Transplants–But Are They Ethical?
80beats: China May Stop Harvesting Organs From Executed Prisoners
80beats: Making Pig Stem Cells Raises the Possibility of Animal Organ Donors
DISCOVER: The Second Coming of Gene Therapy
Image: Science / AAAS
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(Via Discover Health & Medicine.)
Sensium Life Pebble Wireless Vitals Monitor for Sport Training, Cardiac Health Auditing: “
Toumaz Technology out of Abingdon, UK has released the Sensium™ Life Pebble vital sign monitoring device. Featuring a single lead ECG, a skin thermometer, and an accelerometer to monitor physical activity, the unit can track ones performance for later analysis by a clinician.
Device features:
Wireless monitoring of heart rate and activity optimised for ambulatory conditions Accurate electrically-derived heart rate from R to R peak measurements 3-axis accelerometer to detect and measure physical activity Skin temperature sensor Robust data communication, even in noisy channels Up to 5 days’ operational use on a single hearing aid battery Light weight and ultra-small size (20gm with LR44 battery, excluding EKG leads)
Press release: Toumaz Technology Announces Availability of Sensium Life Pebble Wireless Vital Signs Monitor…
(Via Medgadget.)
Nikon Small World 2009 Winners Announced: “
The winners in this year’s Nikon Small World photomicrography contest have been announced. The competition, held annually since 1974, gives a good overview of how optics and digital technology have opened up the beauty of the microworld. Below is the grand prize winner and one of the runners up that we particularly enjoyed.
Heiti Paves, Arabidopsis thaliana (thale cress) anther (20X)
Arlene Wechezak, Algae and diatoms (10X)
Link: Nikon Small World 2009 Winners…
(Via Medgadget.)
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