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Comment by Dr. Krishna Kumari Challa on December 5, 2018 at 6:46am

It is not common but fathers too can pass mitochondrial DNA to their children!

Fathers in three unrelated families passed mitochondria — tiny energy factories found in cells — on to their children, researchers report.

Scientists have long thought that children inherited mitochondria exclusively from their mothers, since mitochondria from the father’s sperm are usually destroyed after fertilizing the egg. The new research, published online November 26, 2018 in the Proceedings of the National Academy of Sciences, suggests that in rare cases dads can contribute mitochondria too. For now, the consequences of inheriting mitochondria from both parents aren’t known.

Mitochondrial disease researcher Paldeep Atwal spotted the paternal signature after examining DNA from a woman who came to the Mayo Clinic in Jacksonville, Fla. DNA in a cell’s nucleus is inherited equally from both parents and contains all the genetic instructions for building a body. Mitochondria have their own DNA, too, that contains some of the genes needed for building and running the organelles. The woman’s cells weirdly contained two types of mitochondrial DNA, some from mom and some “from elsewhere”. 

Thinking the result was a mistake, Atwal and colleagues repeated the test. “The same thing came back the second time, and that’s when the researchers started to get a little bit suspicious”.

The researchers had DNA from both of the woman’s parents, so the team examined the father’s mitochondrial DNA, and found that he was the source of the mystery mitochondria. The woman’s brother also inherited mitochondria from their father. 

So Atwal got in touch with Taosheng Huang, a mitochondrial disease expert at Cincinnati Children’s Hospital Medical Center. It turns out that Huang had examined patients from two other families in which fathers had handed mitochondria down to their children. All together, the researchers found 17 people in the three families who inherited 24 percent to 76 percent of their mitochondria from dad.

http://www.pnas.org/content/early/2018/11/21/1810946115

Comment by Dr. Krishna Kumari Challa on December 5, 2018 at 6:41am

New technique to do biopsy on living cells
A new set of nanotweezers can extract DNA and other single molecules from a living cell without killing it.

Examining the molecular contents of a single cell has traditionally required killing the cell by bursting it open. But that process provides only a single snapshot of the cell’s molecular makeup at the time of its death. The new nanotweezers, reported online December 3 in Nature Nanotechnology, could enable long-term analysis of what’s going on inside individual cells to better understand how healthy cells work and where diseased cells go wrong.

The nanotweezers comprise a glass rod with a tip less than 100 nanometers across, capped with two carbon-based electrodes. Applying an electric voltage to the tweezers creates a powerful electric field in the immediate vicinity of the electrodes, which can attract and trap biomolecules within about 300 nanometers of the tweezer tip.

Once caught in this 300-nanometer net, molecules are stuck until the tweezer voltage turns off. By positioning the needlelike tweezers with extreme precision, researchers can puncture specific cell compartments and fish for particular molecules.
B.P. Nadappuram et al. Nanoscale tweezers for single-cell biopsies. Nature Nanotechnology. Published online December 3, 2018. 

https://www.nature.com/articles/s41565-018-0315-8

Comment by Dr. Krishna Kumari Challa on November 2, 2018 at 8:53am

Scientists are warning that if human beings continue to mine the world’s wildernesses for resources and convert them into cities and farms at the pace of the previous century, the planet’s few remaining wild places could disappear in decades.

Today, more than 77 percent of land on earth, excluding Antarctica, has been modified by human industry, according to a study published recently in the journal Nature, up from just 15 percent a century ago.

The study, led by researchers from the University of Queensland in Australia and the Wildlife Conservation Society in New York, paints the first global picture of the threat to the world’s remaining wildernesses — and the image is bleak.

Wilderness is defined as an area not subject to direct human use.

These areas are the only places on earth that have natural levels of biodiversity, and can continue to sustain plant and animal species on an evolutionary time scale.

Moreover, these spots often act as the world’s lungs, storing carbon dioxide that would otherwise be released into the atmosphere.

Policy experts, take note that even more aggressive action is needed to stop global resource extraction and industrial expansion. 

Healthy ecosystems are crucial in their own right for biodiversity and mitigating climate change, but more importantly, said the researchers, they are home for hundreds of millions of indigenous people, who rely on the wilderness to survive and thrive.

Comment by Dr. Krishna Kumari Challa on October 31, 2018 at 10:03am

60% of world's wildlife has been wiped out since 1970 says WWF

Well over half the world's population of vertebrates, from fish to birds to mammals, have been wiped out in the past four decades, says a new report from the World Wildlife Fund.

Between 1970 and 2014, there was 60 per cent decline, on average, among 16,700 wildlife populations around the world according to the 2018 edition of the Living Planet Report  released recently.

We've had a loss of nearly two-thirds, on average, of our wild species. The magnitude of that should be eye opening… We really are reaching a point where we're likely to see species go extinct.

The WWF says the biggest drivers of the declines are habitat loss and overexploitation, but says climate change is a growing threat. The results of the new report shows a trend in the wrong direction, and "there's a real urgency" to take action to protect wildlife.

Comment by Dr. Krishna Kumari Challa on October 25, 2018 at 10:07am

Brain-eating amoebae halted by silver nanoparticles

Researchers have developed silver nanoparticles coated with anti-seizure drugs that can kill brain-eating amoebae while sparing human cells. The researchers report their results in ACS Chemical Neuroscience.

Although infections with brain-eating amoebae (Naegleria fowleri) are rare, they are almost always deadly. Most cases result from inhaling warm, dirty water in ponds, hot springs or unchlorinated swimming pools. Another species, Acanthamoeba castellanii, can cause blindness by entering the eyes through dirty contact lenses. Common treatments include antimicrobial drugs, but they often cause severe side effects because of the high doses required for them to enter the brain. Ayaz Anwar and colleagues wondered if three anti-seizure drugs -- diazepam, phenobarbitone and phenytoin -- could kill amoebae, alone or in combination with silver nanoparticles. The drugs are already approved by the U.S. Food and Drug Administration and are known to cross the blood-brain barrier. The researchers reasoned that they might be more effective when attached to silver nanoparticles, which can improve the delivery of some drugs and also have their own antimicrobial effects.

The team chemically attached the drugs to silver nanoparticles and examined their ability to kill amoebae. They found that each of the three drugs alone could kill N. fowleri and A. castellanii, but they worked much better when bound to silver nanoparticles. The drug-nanoparticle combos protected human cells from the microbes, increasing their survival rate compared with untreated infected human cells. The researchers propose that these repurposed drugs, aided by the nanoparticles, might kill amoebae by binding to protein receptors or ion channels on the single-celled organism's membrane.

https://pubs.acs.org/doi/abs/10.1021/acschemneuro.8b00484

Comment by Dr. Krishna Kumari Challa on October 24, 2018 at 9:59am

Microplastics have been found in the human food chain as particles made of polypropylene (PP), polyethylene-terephthalate (PET) and others were detected in human stools, research presented recently at the 26th UEG Week in Vienna reveals.

Researchers from the Medical University of Vienna and the Environment Agency Austria monitored a group of participants from countries across the world, including Finland, Italy, Japan, the Netherlands, Poland, Russia, the UK and Austria. The results show that every single stool sample tested positive for the presence of microplastic and up to nine different plastic types were identified.

Microplastics are small particles of plastic less than 5mm and are used in various products for specific purposes; as well as being created unintentionally by the breaking down of larger pieces of plastic through weathering, degradation, wear and tear. Microplastic may impact human health via the GI tract where it could affect the tolerance and immune response of the gut by bioaccumulation or aiding transmission of toxic chemicals and pathogens.
The stools were tested at the Environment Agency Austria for 10 types of plastics following a newly developed analytical procedure. Up to nine different plastics, sized between 50 and 500 micrometres, were found, with polypropylene (PP) and polyethylene terephthalate (PET) being the most common. On average, the researchers found 20 microplastic particles per 10g of stool.
Schwabl, P. et al (2018), Assessment of microplastic concentrations in human stool - Preliminary results of a prospective study, Presented at UEG Week 2018 Vienna, October 24, 2018.

Comment by Dr. Krishna Kumari Challa on October 18, 2018 at 10:28am

Alarming news! Microplastics found in 90% of table salt around the world. 

A paper published in the journal Environmental Science & Technology.

recently says those from Asian brands were especially high. In another indicator of the geographic density of plastic pollution, microplastics levels were highest in sea salt, followed by lake salt and then rock salt. The new study estimates that the average adult consumes approximately 2,000 microplastics per year through salt.

For more information read this article....

https://kkartlab.in/group/some-science/forum/topics/the-perils-of-p...

Comment by Dr. Krishna Kumari Challa on September 14, 2018 at 8:41am

New molecule with sneaky tactics to kill drug-resistant superbugs ...
A new molecule can kill deadly strains of common bacteria, such as Escherichia coli and Klebsiella pneumonia, that are resistant to most existing antibiotics. The drug works differently from currently available antibiotics, potentially making it harder for bacteria to develop resistance, researchers report September 12 in Nature.
Most antibiotics kill bacteria by weakening their cell wall or by preventing the production of certain proteins. But bacteria have, over time, evolved ways to circumvent these drugs.
The newly developed drug uses a different tactic. It inhibits a key enzyme in the cell membrane that helps the bacteria secrete proteins. That means that strategies that bacteria use to evade existing antibiotics won’t work here, giving the molecule an edge. When the enzyme is blocked, proteins build up in the cell membrane until the membrane bursts, ultimately killing the cell.
The molecule will need to go through additional testing and tweaking before it can be used in humans.
P. Smith et al. Optimized arylomycins are a new class of Gram-negative antibiotics. Nature. Published online September 12, 2018. doi: 10.1038/s41586-018-0483-6.

Comment by Dr. Krishna Kumari Challa on August 25, 2018 at 12:19pm

Comment by Dr. Krishna Kumari Challa on July 25, 2018 at 6:02am

Chemical additives in food for kids are highly harmful

The American Academy of Pediatrics is cautioning parents and pediatricians to avoid exposing children to eight chemicals found in food and in plastic packaging. The chemicals may be especially harmful to kids due to their small size, says the report published July 23 in Pediatrics. Pregnant women should also avoid the chemicals. And lower-income families who eat a lot of prepackaged foods could be at greater risk for exposure.

The chemicals include nitrates and nitrites, often added to processed meats as a preservative, as well as bisphenol A, or BPA, which is used to make durable plastics and has been linked to cancer, obesity and cardiovascular disease . Also listed are phthalates, which help make plastic flexible, and perfluoroalkyl chemicals, or PFCs, which are resistant to stains, grease and water. These and other compounds have also been associated with endocrine disruption, obesity and insulin resistance, when cells don’t respond properly to insulin leading to an overproduction of the hormone .

Some of these chemicals may also have neurocognitive effects, such as increased hyperactivity in children, says study coauthor Sheela Sathyanarayana, a physician and epidemiologist at the University of Washington in Seattle.

Scientists are unable to test the effects of these chemicals directly in humans, so evidence shows only that there is correlation, not causation, between exposure and disease.

To avoid these chemicals, the report suggests that parents buy fresh or frozen produce and skip processed meats packaged in plastic or food in metal cans, which can be lined with BPA. People should also avoid putting plastic containers in the dishwasher or microwave, the team says, where heat can draw chemicals out of plastic.

The researchers say that they hope the report prompts more strict regulation of these additives.

L. Trasande, R.M. Shaffer and S. Sathyanarayana. Food additives and child health. Pediatrics. Published online July 23, 2018. doi:10.1542/peds.2018-1408.

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