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Comment by Dr. Krishna Kumari Challa on December 8, 2022 at 9:42am

Discovery of world's oldest DNA breaks record by one million years

Two-million-year-old DNA has been identified for the first time—opening a 'game-changing' new chapter in the history of evolution.

Microscopic fragments of environmental DNA were found in Ice Age sediment in northern Greenland. Using cutting-edge technology, researchers discovered the fragments are one million years older than the previous record for DNA sampled from a Siberian mammoth bone.

The ancient DNA has been used to map a two-million-year-old ecosystem which weathered extreme climate change. Researchers hope the results could help to predict the long-term environmental toll of today's global warming.

Extensive work by 40 researchers from several countries  unlocked the secrets of the fragments of DNA. The process was painstaking—first they needed to establish whether there was DNA hidden in the clay and quartz, and if there was, could they successfully detach the DNA from the sediment to examine it? The answer, eventually, was yes. The researchers compared every single DNA fragment with extensive libraries of DNA collected from present-day animals, plants and microorganisms. A picture began to emerge of the DNA from trees, bushes, birds, animals and microorganisms.

Some of the DNA fragments were easy to classify as predecessors to present-day species, others could only be linked at genus level, and some originated from species impossible to place in the DNA libraries of animals, plants and microorganisms still living in the 21st century.

The two-million-year-old samples also help academics build a picture of a previously unknown stage in the evolution of the DNA of a range of species still in existence today.

Eske Willerslev, A 2-million-year-old ecosystem in Greenland uncovered by environmental DNA, Nature (2022). DOI: 10.1038/s41586-022-05453-y. www.nature.com/articles/s41586-022-05453-y

Comment by Dr. Krishna Kumari Challa on December 7, 2022 at 10:10am

This is what we wanted: EU agrees ban on imports driving deforestation

The European Union reached an agreement yesterday to ban the import of products including coffee, cocoa and soy in cases where they are deemed to contribute to deforestation.

The draft law, which aims to ensure "deforestation-free supply chains" for the 27-nation EU, was hailed by environmental groups as "groundbreaking".

It requires companies importing into the EU to guarantee products are not produced on land that suffered deforestation after December 31, 2020, and that they comply with all laws of the source country.

The scope encompasses palm oil, cattle, soy, coffee, cocoa, timber and rubber as well as derived products such as beef, furniture and chocolate.

Illegal production has spurred massive deforestation in countries such as Brazil, Indonesia, Malaysia, Nigeria, the Democratic Republic of Congo, Ethiopia, Mexico and Guatemala.

The United Nations' Food and Agriculture Organization estimates that an aggregate area of land bigger than the European Union, or some 420 million hectares (more than one billion acres), has been deforested around the world over the past three decades.

The law opened the way for technology such as satellite monitoring and DNA analysis to verify the provenance of targeted imports. The legislation would be reviewed one year after coming into force, to see whether it should be extended to other wooded land. Another review at the two-year mark would have the commission considering whether to expand it to cover other ecosystems and commodities, as well as financial institutions.

WWF, called the agreement "groundbreaking" and "historic".

source: AFP

Comment by Dr. Krishna Kumari Challa on December 6, 2022 at 10:51am

Insulin sensitivity is preserved in mice made obese by feeding a high starch diet

Abstract: Obesity is generally associated with insulin resistance in liver and muscle and increased risk of developing type 2 diabetes, however there is a population of obese people that remain insulin sensitive. Similarly, recent work suggests that mice fed high carbohydrate diets can become obese without apparent glucose intolerance. To investigate this phenomenon further, we fed mice either a high fat (Hi-F) or high starch (Hi-ST) diet and measured adiposity, glucose tolerance, insulin sensitivity, and tissue lipids compared to control mice fed a standard laboratory chow. Both Hi-ST and Hi-F mice accumulated a similar amount of fat and tissue triglyceride compared to chow-fed mice. However, while Hi-F diet mice developed glucose intolerance as well as liver and muscle insulin resistance (assessed via euglycaemic/hyperinsulinaemic clamp), obese Hi-ST mice maintained glucose tolerance and insulin action similar to lean, chow-fed controls. This preservation of insulin action despite obesity in Hi-ST mice was associated with differences in de novo lipogenesis and levels of C22:0 ceramide in liver and C18:0 ceramide in muscle. This indicates that dietary manipulation can influence insulin action independently of the level of adiposity and that the presence of specific ceramide species correlates with these differences.

https://elifesciences.org/articles/79250?utm_source=content_alert&a...

Comment by Dr. Krishna Kumari Challa on December 6, 2022 at 9:37am

Using a green algae capsule to deliver chemotherapeutic drugs to a ...

A team of researchers at the University of California, San Diego, has developed a green algae capsule for delivering chemotherapy drugs to the gastrointestinal (GI) tract. In their study, published in the journal Science Robotics, the group delivered drugs via the capsule, which passed through the stomach without being digested.

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Signs of brain ageing after severe COVID

Severe COVID-19 has been linked to changes in the brain similar to those seen in old age. Scientists studied brain samples from 21 people who had severe SARS-CoV-2 infections when they died. Inflammation and stress genes in the frontal cortex — a brain region essential for cognition — were more active in infected people than in uninfected people, and genes linked to forming connections between brain cells were less active. Proteomics researcher Daniel Martins-de-Souza says the work is preliminary but could ultimately help people who have lingering cognitive difficulties after COVID-19.

Comment by Dr. Krishna Kumari Challa on December 6, 2022 at 9:04am

Researchers harness bacteria-eating viruses to create powerful food decontamination spray

Researchers  have created a powerful new weapon against bacterial contamination and infection.

They have developed a way to coax bacteriophages—harmless viruses that eat bacteria—into linking together and forming microscopic beads. Those beads can safely be applied to food and other materials to rid them of harmful pathogens such as E. coli 0157. Each bead is about 20 microns, (one 50th of a millimeter) in diameter and is loaded with millions of phages.

The researchers' sprayable new super-disinfectant is food-safe and highly effective, as they describe in an article  published recently in the journal Nature Communications.

Self-assembling nanofibrous bacteriophage microgels as sprayable antimicrobials targeting multidrug-resistant bacteria, Nature Communications (2022). DOI: 10.1038/s41467-022-34803-7

Comment by Dr. Krishna Kumari Challa on December 6, 2022 at 8:51am

Study hints at the potentially crucial role of shear stress in the activation of pain sensing neurons

Feelings of pain and discomfort are crucial to the survival and evolution of animals, as they help to detect injuries or existential threats and pinpoint their location in the body. Pain signals are produced by nociceptors, sensory neurons that respond to damage to the body and send "threat" signals to the spinal cord.

Nociceptors (i.e., neurons sensing pain) are essentially bare nerve endings that can be found in all parts of the body, including the skin, muscles, bones and viscera. While many neuroscience studies have investigated their structure and function, the mechanisms underpinning their activation remain poorly understood.

Researchers have recently set out to better understand these mechanisms by conducting experiments on fruit fly larvae. Their findings, published in Neuron, suggest that these neurons specifically respond to shear stress (i.e., stress caused by two forces of similar strength acting on opposite sides of a body and moving in opposite directions), but do not respond to stretch.

The key goal of the recent work was to identify the specific forces that lead to the activation of these pain sensing neurons and elucidate the underlying transduction mechanisms. To do this, the researchers first conducted behavioral experiments, where they poked a fruit fly larva using a calibrated fishing line. "In the absence of stimulation, larvae tend to move forward with frequent changing of direction. However, when they poked a larva, it stopped moving and displayed a 360-degree body rotation. This rolling was interpreted as nocifensive behaviour (i.e., animal behavior aimed at withdrawing from danger). The strength of response was measured as a percentage of animals that rolled in response to poking. Using computer modeling, the team found that poking a fruit fly larva could elicit two different kinds of forces, stretch and shear stress to stimulate nociceptors. In the following calcium imaging experiments to explore which forces are responsible for nociceptor activation, the researchers stretched the larvae's nociceptors or apply a shear force to them. They found that the larvae's nociceptors were activated by shear stress, but not by stretch. They were also able to identify the specific type of ion channel that is found in nociceptors and is activated by shear stress, called transient receptor potential A1 (TrpA1). Interestingly, shear stress appeared to be able to activate TrpA1 in a small patch of cell membrane devoid of cellular environment, providing evidence of TrpA1 as a molecular sensor of shear stress. They further show the effect of shear stress was through modulation of membrane's fluidity.

This study has two notable findings:First, the researchers showed that shear stress could be a physiologically relevant force that is critical for activation of nociceptors. Second, it provided evidence that TrpA1 is a shear stress sensor and this property is conserved for TrpA1 derived from Drosophila, mice and humans.

Jiaxin Gong et al, Shear stress activates nociceptors to drive Drosophila mechanical nociception, Neuron (2022). DOI: 10.1016/j.neuron.2022.08.015

Comment by Dr. Krishna Kumari Challa on December 5, 2022 at 9:16am

Mapping the hidden connections between diseases

A new study by  researchers has identified patterns in how common health conditions occur together in the same individuals, using data from 4 million patients.

With advancing age, millions of people live with multiple conditions—sometimes referred to as multimorbidity—and the proportion of people affected in this way is expected to rise over the next decades. However, medical education and training, health care delivery, clinical guidelines and research have evolved to focus on one disease at a time.

The Academy of Medical Sciences and the UK Chief Medical Officer (CMO) have recognized this problem and set out a challenge of investigating which diseases co-occur in the same individuals and why.

In the new study, published in The Lancet Digital Health, the team used routine health records data to systematically identify patterns of clustering of 308 common mental and physical health conditions of men and women of different ages and with different ethnicities.

Some patterns found include: heart failure often co-occurred with hypertension, atrial fibrillation, osteoarthritis, stable angina, myocardial infarction, chronic kidney disease, type 2 diabetes, and chronic obstructive pulmonary disease.

Hypertension was most strongly associated with kidney disorders in those aged 20–29 years, but with dyslipidaemia, obesity, and type 2 diabetes in individuals aged 40 years and older.

Breast cancer was associated with different comorbidities in individuals from different ethnicities, asthma with different comorbidities between the sexes, and bipolar disorder with different comorbidities in younger ages compared with older ages.

Millions of people live with multiple diseases, yet our understanding of how and when these transpire is limited. This research project is the first step towards understanding how these diseases co-occur and identifying how to best treat them.

The study includes accessible tools to help users visualize patterns of disease co-occurrence, including for diseases that cluster more commonly than expected by chance, providing an entry point to investigate common risk factors and treatments.

The findings should help patients better understand their illness, doctors better plan management of patients with multimorbidity, health care providers optimize service delivery, policy makers plan resource allocation, and researchers to develop new or use existing medicines to treat several diseases together.

Valerie Kuan et al, Identifying and visualising multimorbidity and comorbidity patterns in patients in the English National Health Service: a population-based study, The Lancet Digital Health (2022). DOI: 10.1016/S2589-7500(22)00187-X

The findings, the researchers say, provide the data and resources to help improve health and care planning for patients in England living with more than one condition.

Comment by Dr. Krishna Kumari Challa on December 4, 2022 at 12:18pm

Janavis: new species of toothed bird from the Age of Dinosaurs

Comment by Dr. Krishna Kumari Challa on December 4, 2022 at 12:16pm

Brain cells use a telephone trick to report what they see

"How many fingers am I holding up?”

For vision-sensing brain cells in a monkey’s visual cortex, that answer depends on whether the digits are next to each other or partially overlapping.

A new study from Duke University finds that single neurons conveying visual information about two separate objects in sight do so by alternating signals about one or the other. When two objects overlap, however, the brain cells detect them as a single entity.

The new report is out Nov. 28 in the journal eLife.

The findings help expand what is known about how the brain makes sense of its complicated and busy world. Most research on sensory processing, be it sounds or sights, sets the bar too low by testing how brain cells react to a single tone or image.

This study is the first one  to show that single auditory brain cells efficiently transmit information about two different sounds by using something called multiplexing.

Multiplexing is an idea that comes from engineering. When you have one wire and a lot of signals, you can swap the signals out, kind of like a telephone party line.

The telecommunications technology works by rapidly switching back-and-forth between relaying information from one phone call and the other using just one wire. In the brain, the switching is probably happening much more slowly but the general idea is similar.

“Coordinated Multiplexing of Information About Separate Objects in Visual Cortex,” Na Young Jun, Douglas A. Ruff, Lily E. Kramer, Brittany Bowes, Surya T. Tokdar, Marlene R. Cohen, Jennifer M. Groh. eLife, Nov. 29, 2022. DOI: 10.7554/eLife.76452.sa0

Comment by Dr. Krishna Kumari Challa on December 4, 2022 at 11:52am

Researchers discover new form of antimicrobial resistance

Researchers have uncovered a new form of antimicrobial resistance (AMR), undetectable using traditional laboratory testing methods, in a discovery set to challenge existing efforts to monitor and tackle one of the world's greatest health threats.

In research published today in Nature Communications, the researchers revealed a new mechanism that enables bacteria to take up nutrients from their human host and bypass antibiotic treatment. The researchers made the discovery while investigating antibiotic susceptibility of group A. streptococcus—a potentially deadly bacteria often found in the throat and on the skin.

Bacteria need to make their own folates to grow, and in turn, cause disease. Some antibiotics work by blocking this folate production to stop bacteria growing and treat the infection. When looking at an antibiotic commonly prescribed to treat group A. strep skin infections, researchers found a mechanism of resistance, where for the first time ever, the bacteria demonstrated the ability to take folates directly from its human host when blocked from producing their own. This makes the antibiotic ineffective and the infection would likely worsen when the patient should be getting better.

This new form of resistance is undetectable under conditions routinely used in pathology laboratories, making it very hard for clinicians to prescribe antibiotics that will effectively treat the infection, potentially leading to very poor outcomes and even premature death.

Researchers  suspect that this is just the tip of the iceberg—they have identified this mechanism in group A. strep but it's likely it will be a broader issue across other bacterial pathogens.

Host-dependent resistance of Group A Streptococcus to sulfamethoxazolemediated by a horizontally-acquired reduced folate transporter, Nature Communications (2022). DOI: 10.1038/s41467-022-34243-3

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