Placenta changes could mean male offspring of older mums more likely to develop heart problems in later life, rat study finds.
Changes occur in the placenta in older pregnant mothers leading to a greater likelihood of poor health in their male offspring, a study in rats has shown. Both male and female fetuses do not grow as large in older mothers, but there are sex-specific differences in changes to placental development and function. These are likely to play a central role in the increased likelihood of later-life heart problems and high blood pressure in males.
In humans, women over 35 are considered to be of advanced maternal age. The study, published in Scientific Reports, looked at pregnant rats of a comparable age. In aged mothers, the placenta of female fetuses showed beneficial changes in structure and function that would maximise the support of fetal growth. In some instances, the placenta even supported the female fetus better than the placenta of a younger mother. In the case of male fetuses however, the placenta showed changes that would limit fetal growth in the aged pregnant rats.
"This new understanding of placental development and function could contribute to better management of human pregnancies, and development of targeted interventions to improve the longer-term health of children born to older mothers," said Dr Tina Napso, a postdoctoral fellow at the University of Cambridge and first author of the study.
Pregnancy in older mothers is associated with a heightened risk of complications for both the mother and her baby. These include preeclampsia -- raised blood pressure in the mother during pregnancy, gestational diabetes, stillbirth and fetal growth restriction. Until now there has been limited understanding of how the placenta is altered by advanced maternal age.
"With the average age of first pregnancy in women becoming higher and higher, and especially so in developed countries, it is very important to understand how the age of the mother and the sex of the baby interact to determine pregnancy and later-life health of the child," said Dr Amanda Sferruzzi-Perri, lead author of the study and a Royal Society Fellow in the Centre for Trophoblast Research at the University of Cambridge's Department of Physiology, Development and Neuroscience.
The placenta transports nutrients and oxygen from mother to fetus, secretes signalling factors into the mother so she supports fetal development, and is the main protective barrier for the fetus against toxins, bacteria, and hormones -- such as stress hormones -- in the mother's blood. It is highly dynamic in nature, and its function can change to help protect the growing fetus when conditions become less favourable for its development, for example through a lack of nutrients or oxygen or when the mother is stressed.
The researchers analysed the placentas of young (3-4 months old) and aged rats (9.5-10 months old) that were pregnant with male and female offspring. The aged rats correspond to approximately 35 year-old humans. Rats are a useful model as their biology and physiology have a number of important characteristics in common with those of humans.
The study found that advanced maternal age reduced the efficiency of the placenta of both male and female fetuses. It affected the structure and function of the placenta more markedly for male fetuses, reducing its ability to support growth of the fetus.
"A pregnancy at an older age is a costly proposition for the mother, whose body has to decide how nutrients are shared with the fetus. That's why, overall, fetuses do not grow sufficiently during pregnancy when the mother is older compared to when she is young," said Dr Napso. "We now know that growth, as well as gene expression in the placenta is affected in older mothers in a manner that partially depends on sex: changes in the placentas of male fetuses are generally detrimental."
The research involved a collaboration between scientists at the University of Cambridge, the University of Alberta in Canada, the Robinson Research Institute and the University of Adelaide, Australia.
An earlier study performed by the collaborators showed that offspring from mothers who enter pregnancy at an older age have poor heart function and high blood pressure as young adults, and particularly so if they are male. This new research was conducted to understand why, and whether this sex difference may be due to how the male and female fetuses are supported within the womb in an aged mother.
Read more at Science Daily
Dec 1, 2019
Nov 30, 2019
We love coffee, tea, chocolate and soft drinks so much, caffeine is literally in our blood
Scientists at Oregon State University may have proven how much people love coffee, tea, chocolate, soda and energy drinks as they validated their new method for studying how different drugs interact in the body.
In conducting mass spectrometry research, Richard van Breemen and Luying Chen worked with various biomedical suppliers to purchase 18 batches of supposedly pure human blood serum pooled from multiple donors. Biomedical suppliers get their blood from blood banks, who pass along inventory that's nearing its expiration date.
All 18 batches tested positive for caffeine. Also, in many of the samples the researchers found traces of cough medicine and an anti-anxiety drug. The findings point to the potential for contaminated blood transfusions, and also suggest that blood used in research isn't necessarily pure.
"From a 'contamination' standpoint, caffeine is not a big worry for patients, though it may be a commentary on current society," said Chen, a Ph.D. student. "But the other drugs being in there could be an issue for patients, as well as posing a problem for those of us doing this type of research because it's hard to get clean blood samples."
The study was published in the Journal of Pharmaceutical and Biomedical Analysis.
In addition to caffeine, the research also involved testing pooled serum for alprazolam, an anti-anxiety medicine sold under the trade name Xanax; dextromethorphan, an over-the-counter cough suppressant; and tolbutamide, a medicine used to treat type 2 diabetes.
All of the pooled serum was free of tolbutamide, but eight samples contained dextromethorphan and 13 contained alprazolam -- possibly meaning that if you ever need a blood transfusion, your odds of also receiving caffeine, cough medicine and an anti-anxiety drug are pretty good.
"The study leads you in that direction, though without doing a comprehensive survey of vendors and blood banks we can only speculate on how widespread the problem is," said van Breemen, the director of OSU's Linus Pauling Institute. "Another thing to consider is that we found drugs that we just happened to be looking for in doing the drug interaction assay validation -- how many others are in there too that we weren't looking for?"
The purpose of the study by Chen and van Breemen was to test a new method for evaluating the potential for interactions between botanical dietary supplements and drug metabolism.
The method involves rapid protein precipitation and ultra high pressure liquid chromatography and is being used to support clinical studies. In the clinical studies, participants take a drug cocktail along with a botanical supplement -- hops, licorice or red clover -- to see if the supplement causes any of the drugs to be metabolized differently than they otherwise would.
"Botanicals basically contain natural products with drug-like activities," van Breemen said. "Just as a drug may alter the drug-metabolizing enzymes, so can natural products. It can become a real problem when someone takes a botanical supplement and is also on prescription drugs -- how do those two interact? It's not straightforward or necessarily predictable, thus the need for methods to look for these interactions. The odd thing in this case was finding all the tainted blood."
Read more at Science Daily
In conducting mass spectrometry research, Richard van Breemen and Luying Chen worked with various biomedical suppliers to purchase 18 batches of supposedly pure human blood serum pooled from multiple donors. Biomedical suppliers get their blood from blood banks, who pass along inventory that's nearing its expiration date.
All 18 batches tested positive for caffeine. Also, in many of the samples the researchers found traces of cough medicine and an anti-anxiety drug. The findings point to the potential for contaminated blood transfusions, and also suggest that blood used in research isn't necessarily pure.
"From a 'contamination' standpoint, caffeine is not a big worry for patients, though it may be a commentary on current society," said Chen, a Ph.D. student. "But the other drugs being in there could be an issue for patients, as well as posing a problem for those of us doing this type of research because it's hard to get clean blood samples."
The study was published in the Journal of Pharmaceutical and Biomedical Analysis.
In addition to caffeine, the research also involved testing pooled serum for alprazolam, an anti-anxiety medicine sold under the trade name Xanax; dextromethorphan, an over-the-counter cough suppressant; and tolbutamide, a medicine used to treat type 2 diabetes.
All of the pooled serum was free of tolbutamide, but eight samples contained dextromethorphan and 13 contained alprazolam -- possibly meaning that if you ever need a blood transfusion, your odds of also receiving caffeine, cough medicine and an anti-anxiety drug are pretty good.
"The study leads you in that direction, though without doing a comprehensive survey of vendors and blood banks we can only speculate on how widespread the problem is," said van Breemen, the director of OSU's Linus Pauling Institute. "Another thing to consider is that we found drugs that we just happened to be looking for in doing the drug interaction assay validation -- how many others are in there too that we weren't looking for?"
The purpose of the study by Chen and van Breemen was to test a new method for evaluating the potential for interactions between botanical dietary supplements and drug metabolism.
The method involves rapid protein precipitation and ultra high pressure liquid chromatography and is being used to support clinical studies. In the clinical studies, participants take a drug cocktail along with a botanical supplement -- hops, licorice or red clover -- to see if the supplement causes any of the drugs to be metabolized differently than they otherwise would.
"Botanicals basically contain natural products with drug-like activities," van Breemen said. "Just as a drug may alter the drug-metabolizing enzymes, so can natural products. It can become a real problem when someone takes a botanical supplement and is also on prescription drugs -- how do those two interact? It's not straightforward or necessarily predictable, thus the need for methods to look for these interactions. The odd thing in this case was finding all the tainted blood."
Read more at Science Daily
Ultrafast quantum simulations: A new twist to an old approach
Billions of tiny interactions occur between thousands of particles in every piece of matter in the blink of an eye. Simulating these interactions in their full dynamics was said to be elusive but has now been made possible by new work of researchers from Oxford and Warwick.
In doing so, they have paved the way for new insights into the complex mutual interactions between the particles in extreme environments such as at the heart of large planets or laser nuclear fusion.
Researchers at the University of Warwick and University of Oxford have developed a new way to simulate quantum systems of many particles, that allows for the investigation of the dynamic properties of quantum systems fully coupled to slowly moving ions.
Effectively, they have made the simulation of the quantum electrons so fast that it could run extremely long without restrictions and the effect of their motion on the movement of the slow ions would be visible.
Reported in the journal Science Advances, it is based on a long-known alternative formulation of quantum mechanics (Bohm dynamics) which the scientists have now empowered to allow to study the dynamics of large quantum systems.
Many quantum phenomena have been studied for single or just a few interacting particles as large complex quantum systems overpower scientists' theoretical and computational capabilities to make predictions. This is complicated by the vast difference in timescale the different particle species act on: ions evolve thousands of times more slowly than electrons due to their larger mass. To overcome this problem, most methods involve decoupling electrons and ions and ignoring the dynamics of their interactions -- but this severely limits our knowledge on quantum dynamics.
To develop a method that allows scientists to account for the full electron-ion interactions, the researchers revived an old alternative formulation of quantum mechanics developed by David Bohm. In quantum mechanics, one needs to know the wave function of a particle. It turns out that describing it by the mean trajectory and a phase, as done by Bohm, is very advantageous. However, it took an additional suit of approximations and many tests to speed up the calculations as dramatic as required. Indeed, the new methods demonstrated an increase of speed by more than a factor of 10,000 (four orders of magnitude) yet is still consistent with previous calculations for static properties of quantum systems.
The new approach was then applied to a simulation of warm dense matter, a state between solids and hot plasmas, that is known for its inherent coupling of all particle types and the need for a quantum description. In such systems, both the electrons and the ions can have excitations in the form of waves and both waves will influence each other. Here, the new approach can show its strength and determined the influence of the quantum electrons on the waves of the classical ions while the static properties were proven to agree with previous data.
Many-body quantum systems are the core of many scientific problem ranging from the complex biochemistry in our bodies to the behaviour of matter inside of large planets or even technological challenges like high-temperature superconductivity or fusion energy which demonstrates the possible range of applications of the new approach.
Prof Gianluca Gregori (Oxford), who led the investigation, said: "Bohm quantum mechanics has often been treated with skepticism and controversy. In its original formulation, however, this is just a different reformulation of quantum mechanics. The advantage in employing this formalism is that different approximations become simpler to implement and this can increase the speed and accuracy of simulations involving many-body systems."
Dr Dirk Gericke from the University of Warwick, who assisted the design of the new computer code, said: "With this huge increase of numerical efficiency, it is now possible to follow the full dynamics of fully interacting electron-ion systems. This new approach thus opens new classes of problems for efficient solutions, in particular, where either the system is evolving or where the quantum dynamics of the electrons has a significant effect on the heavier ions or the entire system.
Read more at Science Daily
In doing so, they have paved the way for new insights into the complex mutual interactions between the particles in extreme environments such as at the heart of large planets or laser nuclear fusion.
Researchers at the University of Warwick and University of Oxford have developed a new way to simulate quantum systems of many particles, that allows for the investigation of the dynamic properties of quantum systems fully coupled to slowly moving ions.
Effectively, they have made the simulation of the quantum electrons so fast that it could run extremely long without restrictions and the effect of their motion on the movement of the slow ions would be visible.
Reported in the journal Science Advances, it is based on a long-known alternative formulation of quantum mechanics (Bohm dynamics) which the scientists have now empowered to allow to study the dynamics of large quantum systems.
Many quantum phenomena have been studied for single or just a few interacting particles as large complex quantum systems overpower scientists' theoretical and computational capabilities to make predictions. This is complicated by the vast difference in timescale the different particle species act on: ions evolve thousands of times more slowly than electrons due to their larger mass. To overcome this problem, most methods involve decoupling electrons and ions and ignoring the dynamics of their interactions -- but this severely limits our knowledge on quantum dynamics.
To develop a method that allows scientists to account for the full electron-ion interactions, the researchers revived an old alternative formulation of quantum mechanics developed by David Bohm. In quantum mechanics, one needs to know the wave function of a particle. It turns out that describing it by the mean trajectory and a phase, as done by Bohm, is very advantageous. However, it took an additional suit of approximations and many tests to speed up the calculations as dramatic as required. Indeed, the new methods demonstrated an increase of speed by more than a factor of 10,000 (four orders of magnitude) yet is still consistent with previous calculations for static properties of quantum systems.
The new approach was then applied to a simulation of warm dense matter, a state between solids and hot plasmas, that is known for its inherent coupling of all particle types and the need for a quantum description. In such systems, both the electrons and the ions can have excitations in the form of waves and both waves will influence each other. Here, the new approach can show its strength and determined the influence of the quantum electrons on the waves of the classical ions while the static properties were proven to agree with previous data.
Many-body quantum systems are the core of many scientific problem ranging from the complex biochemistry in our bodies to the behaviour of matter inside of large planets or even technological challenges like high-temperature superconductivity or fusion energy which demonstrates the possible range of applications of the new approach.
Prof Gianluca Gregori (Oxford), who led the investigation, said: "Bohm quantum mechanics has often been treated with skepticism and controversy. In its original formulation, however, this is just a different reformulation of quantum mechanics. The advantage in employing this formalism is that different approximations become simpler to implement and this can increase the speed and accuracy of simulations involving many-body systems."
Dr Dirk Gericke from the University of Warwick, who assisted the design of the new computer code, said: "With this huge increase of numerical efficiency, it is now possible to follow the full dynamics of fully interacting electron-ion systems. This new approach thus opens new classes of problems for efficient solutions, in particular, where either the system is evolving or where the quantum dynamics of the electrons has a significant effect on the heavier ions or the entire system.
Read more at Science Daily
Nov 29, 2019
Nine climate tipping points now 'active,' warn scientists
More than half of the climate tipping points identified a decade ago are now "active," a group of leading scientists have warned.
This threatens the loss of the Amazon rainforest and the great ice sheets of Antarctica and Greenland, which are currently undergoing measurable and unprecedented changes much earlier than expected.
This "cascade" of changes sparked by global warming could threaten the existence of human civilisations.
Evidence is mounting that these events are more likely and more interconnected than was previously thought, leading to a possible domino effect.
In an article in the journal Nature, the scientists call for urgent action to reduce greenhouse gas emissions to prevent key tipping points, warning of a worst-case scenario of a "hothouse," less habitable planet.
"A decade ago we identified a suite of potential tipping points in the Earth system, now we see evidence that over half of them have been activated," said lead author Professor Tim Lenton, director of the Global Systems Institute at the University of Exeter.
"The growing threat of rapid, irreversible changes means it is no longer responsible to wait and see. The situation is urgent and we need an emergency response."
Co-author Johan Rockström, director of the Potsdam Institute for Climate Impact Research, said: "It is not only human pressures on Earth that continue rising to unprecedented levels.
"It is also that as science advances, we must admit that we have underestimated the risks of unleashing irreversible changes, where the planet self-amplifies global warming.
"This is what we now start seeing, already at 1°C global warming.
"Scientifically, this provides strong evidence for declaring a state of planetary emergency, to unleash world action that accelerates the path towards a world that can continue evolving on a stable planet."
In the commentary, the authors propose a formal way to calculate a planetary emergency as risk multiplied by urgency.
Tipping point risks are now much higher than earlier estimates, while urgency relates to how fast it takes to act to reduce risk.
Exiting the fossil fuel economy is unlikely before 2050, but with temperature already at 1.1°C above pre-industrial temperature, it is likely Earth will cross the 1.5°C guardrail by 2040. The authors conclude this alone defines an emergency.
Nine active tipping points:
The collapse of major ice sheets on Greenland, West Antarctica and part of East Antarctica would commit the world to around 10 metres of irreversible sea-level rise.
Reducing emissions could slow this process, allowing more time for low-lying populations to move.
The rainforests, permafrost and boreal forests are examples of biosphere tipping points that if crossed result in the release of additional greenhouse gases amplifying warming.
Despite most countries having signed the Paris Agreement, pledging to keep global warming well below 2°C, current national emissions pledges -- even if they are met -- would lead to 3°C of warming.
Although future tipping points and the interplay between them is difficult to predict, the scientists argue: "If damaging tipping cascades can occur and a global tipping cannot be ruled out, then this is an existential threat to civilization.
"No amount of economic cost-benefit analysis is going to help us. We need to change our approach to the climate problem."
Professor Lenton added: "We might already have crossed the threshold for a cascade of inter-related tipping points.
"However, the rate at which they progress, and therefore the risk they pose, can be reduced by cutting our emissions."
Read more at Science Daily
This threatens the loss of the Amazon rainforest and the great ice sheets of Antarctica and Greenland, which are currently undergoing measurable and unprecedented changes much earlier than expected.
This "cascade" of changes sparked by global warming could threaten the existence of human civilisations.
Evidence is mounting that these events are more likely and more interconnected than was previously thought, leading to a possible domino effect.
In an article in the journal Nature, the scientists call for urgent action to reduce greenhouse gas emissions to prevent key tipping points, warning of a worst-case scenario of a "hothouse," less habitable planet.
"A decade ago we identified a suite of potential tipping points in the Earth system, now we see evidence that over half of them have been activated," said lead author Professor Tim Lenton, director of the Global Systems Institute at the University of Exeter.
"The growing threat of rapid, irreversible changes means it is no longer responsible to wait and see. The situation is urgent and we need an emergency response."
Co-author Johan Rockström, director of the Potsdam Institute for Climate Impact Research, said: "It is not only human pressures on Earth that continue rising to unprecedented levels.
"It is also that as science advances, we must admit that we have underestimated the risks of unleashing irreversible changes, where the planet self-amplifies global warming.
"This is what we now start seeing, already at 1°C global warming.
"Scientifically, this provides strong evidence for declaring a state of planetary emergency, to unleash world action that accelerates the path towards a world that can continue evolving on a stable planet."
In the commentary, the authors propose a formal way to calculate a planetary emergency as risk multiplied by urgency.
Tipping point risks are now much higher than earlier estimates, while urgency relates to how fast it takes to act to reduce risk.
Exiting the fossil fuel economy is unlikely before 2050, but with temperature already at 1.1°C above pre-industrial temperature, it is likely Earth will cross the 1.5°C guardrail by 2040. The authors conclude this alone defines an emergency.
Nine active tipping points:
- Arctic sea ice
- Greenland ice sheet
- Boreal forests
- Permafrost
- Atlantic Meridional Overturning Circulation
- Amazon rainforest
- Warm-water corals
- West Antarctic Ice Sheet
- Parts of East Antarctica
The collapse of major ice sheets on Greenland, West Antarctica and part of East Antarctica would commit the world to around 10 metres of irreversible sea-level rise.
Reducing emissions could slow this process, allowing more time for low-lying populations to move.
The rainforests, permafrost and boreal forests are examples of biosphere tipping points that if crossed result in the release of additional greenhouse gases amplifying warming.
Despite most countries having signed the Paris Agreement, pledging to keep global warming well below 2°C, current national emissions pledges -- even if they are met -- would lead to 3°C of warming.
Although future tipping points and the interplay between them is difficult to predict, the scientists argue: "If damaging tipping cascades can occur and a global tipping cannot be ruled out, then this is an existential threat to civilization.
"No amount of economic cost-benefit analysis is going to help us. We need to change our approach to the climate problem."
Professor Lenton added: "We might already have crossed the threshold for a cascade of inter-related tipping points.
"However, the rate at which they progress, and therefore the risk they pose, can be reduced by cutting our emissions."
Read more at Science Daily
Unique sled dogs helped the inuit thrive in the North American Arctic
Inuit sled dogs have changed little since people migrated to the North American Arctic across the Bering Strait from Siberia with them, according to researchers who have examined DNA from the dogs from that time span. The legacy of these Inuit dogs survives today in Arctic sled dogs, making them one of the last remaining descendant populations of indigenous, pre-European dog lineages in the Americas.
The latest research is the result of nearly a decade's work by University of California, Davis, researchers in anthropology and veterinary genetics, who analyzed the DNA of hundreds of dogs' ancient skeletal remains to determine that the Inuit dog had significantly different DNA than other Arctic dogs, including malamutes and huskies.
The article, "Specialized sledge dogs accompanied the Inuit dispersal across the North American Arctic," was published Wednesday in the Proceedings of the Royal Society B: Biological Sciences. From UC Davis, authors include Christyann Darwent, professor of anthropology; Ben Sacks, adjunct professor and director of the Mammalian Ecology and Conservation Unit, Veterinary Genetics Laboratory, School of Veterinary Medicine; and Sarah Brown, a postdoctoral researcher. Lead author Carly Ameen is an archaeologist from the University of Exeter; Tatiana Feuerborn is with the Globe Institute in Denmark and Centre for Palaeogenetics in Sweden; and Allowen Evin is at the CNRS, Université de Montpellier, Institut des Sciences de l'Evolution in Montpellier, France. The list of authors includes many others from a large number of collaborating institutions.
Qimmiit (dogs in Inuktitut) were viewed by the Inuit as particularly well-suited to long-distance hauling of people and their goods across the Arctic and consuming local resources, such as sea mammals, for food.
The unique group of dogs helped the Inuit conquer the tough terrain of the North American Arctic 2,000 years ago, researchers said. Inuit dogs are the direct ancestors of modern Arctic sled dogs, and although their appearance has continued to change over time, they continue to play an important role in Arctic communities.
Experts examined the DNA from 921 dogs and wolves who lived during the last 4,500 years. Analysis of the DNA, and the locations and time periods in which they were recovered archaeologically, shows dogs from Inuit sites occupied beginning around 2,000 years ago were genetically different from dogs already in the region.
According to Sacks "the genetic profiles of ancient dogs of the American Arctic dating to 2,000 years ago were nearly identical to those of older dogs from Siberia, but contrasted starkly with those of more ancient dogs in the Americas, providing an unusually clear and definitive picture of the canine replacement event that coincided with the expansion of Thule peoples across the American Arctic two millennia ago."
Read more at Science Daily
The latest research is the result of nearly a decade's work by University of California, Davis, researchers in anthropology and veterinary genetics, who analyzed the DNA of hundreds of dogs' ancient skeletal remains to determine that the Inuit dog had significantly different DNA than other Arctic dogs, including malamutes and huskies.
The article, "Specialized sledge dogs accompanied the Inuit dispersal across the North American Arctic," was published Wednesday in the Proceedings of the Royal Society B: Biological Sciences. From UC Davis, authors include Christyann Darwent, professor of anthropology; Ben Sacks, adjunct professor and director of the Mammalian Ecology and Conservation Unit, Veterinary Genetics Laboratory, School of Veterinary Medicine; and Sarah Brown, a postdoctoral researcher. Lead author Carly Ameen is an archaeologist from the University of Exeter; Tatiana Feuerborn is with the Globe Institute in Denmark and Centre for Palaeogenetics in Sweden; and Allowen Evin is at the CNRS, Université de Montpellier, Institut des Sciences de l'Evolution in Montpellier, France. The list of authors includes many others from a large number of collaborating institutions.
Qimmiit (dogs in Inuktitut) were viewed by the Inuit as particularly well-suited to long-distance hauling of people and their goods across the Arctic and consuming local resources, such as sea mammals, for food.
The unique group of dogs helped the Inuit conquer the tough terrain of the North American Arctic 2,000 years ago, researchers said. Inuit dogs are the direct ancestors of modern Arctic sled dogs, and although their appearance has continued to change over time, they continue to play an important role in Arctic communities.
Experts examined the DNA from 921 dogs and wolves who lived during the last 4,500 years. Analysis of the DNA, and the locations and time periods in which they were recovered archaeologically, shows dogs from Inuit sites occupied beginning around 2,000 years ago were genetically different from dogs already in the region.
According to Sacks "the genetic profiles of ancient dogs of the American Arctic dating to 2,000 years ago were nearly identical to those of older dogs from Siberia, but contrasted starkly with those of more ancient dogs in the Americas, providing an unusually clear and definitive picture of the canine replacement event that coincided with the expansion of Thule peoples across the American Arctic two millennia ago."
Read more at Science Daily
Researchers study chickens, ostriches, penguins to learn how flight feathers evolved
If you took a careful look at the feathers on a chicken, you'd find many different forms within the same bird -- even within a single feather. The diversity of feather shapes and functions expands vastly when you consider the feathers of birds ranging from ostriches to penguins to hummingbirds. Now, researchers reporting in the journal Cell on November 27 have taken a multidisciplinary approach to understanding how all those feathers get made.
"We always wonder how birds can fly and in different ways," says corresponding author Cheng-Ming Chuong of the University of Southern California, Los Angeles. "Some soar like eagles, while others require rapid flapping of wings like hummingbirds." Some birds, including ostriches and penguins, don't fly at all.
"Such differences in flight styles are largely due to the characteristics of their flight feathers," Chuong adds. "We wanted to learn how flight feathers are made so we can understand nature better and learn principles of bioinspired architecture."
In the new study, the researchers put together a multidisciplinary team to look at feathers in many different ways, from their biophysical properties to the underlying molecular biology that allows their formation from stem cells in the skin. They examined the feathers of flightless ostriches, short-distance flying chickens, soaring ducks and eagles, and high-frequency flying sparrows. They studied the extremes by including hummingbirds and penguins. To better understand how feathers have evolved and changed over evolutionary time, the team also looked to feathers that are nearly 100 million years old, found embedded and preserved in amber in Myanmar.
Based on their findings, the researchers explain that feathers' modular structure allowed birds to adapt over evolutionary time, helping them to succeed in the many different environments in which birds live today. Their structure also allows for the specialization of feathers in different parts of an individual bird's body.
The flight feather is made of two highly adaptable architectural modules: the central shaft, or rachis, and the peripheral vane. The rachis is a composite beam made of a porous medulla that keeps feathers light surrounded by a rigid cortex that adds strength. Their studies show that these two components of the rachis allow for highly flexible designs that enabled to fly or otherwise get around in different ways. The researchers also revealed the underlying molecular signals, including Bmp and Ski, that guide the development of those design features.
Attached to the rachis is the feather vane. The vane is the part of the feather made up of many soft barbs that zip together. The researchers report that the vane develops using principles akin to paper cutting. As such, a single epithelial sheet produces a series of diverse, branched designs with individual barbs, each bearing many tiny hooklets that hold the vane together into a plane using a Velcro-like mechanism. Their studies show that gradients in another signaling pathway (Wnt2b) play an important role in the formation of those barbs.
To look back in time, the researchers studied recently discovered amber fossils, allowing them to explore delicate, three-dimensional feather structures. Their studies show that ancient feathers had the same basic architecture but with more primitive characteristics. For instance, adjacent barbs formed the vane with overlapping barbules, without the Velcro-like, hooklet mechanism found in living birds.
"We've learned how a simple skin can be transformed into a feather, how a prototypic feather structure can be transformed into downy, contour, or flight feathers, and how a flight feather can be modulated to adapt to different flight modes required for different living environments," Chuong says. "In every corner and at different morphological scales, we were amazed at how the elegant adaption of the prototype architecture can help different birds to adapt to different new environments."
The researchers say that, in addition to helping to understand how birds have adapted over time, they hope these bioinspired architectural principles they've uncovered can be useful in future technology design. They note that composite materials of the future could contribute toward the construction of light but robust flying drones, durable and resilient wind turbines, or better medical implants and prosthetic devices.
Read more at Science Daily
"We always wonder how birds can fly and in different ways," says corresponding author Cheng-Ming Chuong of the University of Southern California, Los Angeles. "Some soar like eagles, while others require rapid flapping of wings like hummingbirds." Some birds, including ostriches and penguins, don't fly at all.
"Such differences in flight styles are largely due to the characteristics of their flight feathers," Chuong adds. "We wanted to learn how flight feathers are made so we can understand nature better and learn principles of bioinspired architecture."
In the new study, the researchers put together a multidisciplinary team to look at feathers in many different ways, from their biophysical properties to the underlying molecular biology that allows their formation from stem cells in the skin. They examined the feathers of flightless ostriches, short-distance flying chickens, soaring ducks and eagles, and high-frequency flying sparrows. They studied the extremes by including hummingbirds and penguins. To better understand how feathers have evolved and changed over evolutionary time, the team also looked to feathers that are nearly 100 million years old, found embedded and preserved in amber in Myanmar.
Based on their findings, the researchers explain that feathers' modular structure allowed birds to adapt over evolutionary time, helping them to succeed in the many different environments in which birds live today. Their structure also allows for the specialization of feathers in different parts of an individual bird's body.
The flight feather is made of two highly adaptable architectural modules: the central shaft, or rachis, and the peripheral vane. The rachis is a composite beam made of a porous medulla that keeps feathers light surrounded by a rigid cortex that adds strength. Their studies show that these two components of the rachis allow for highly flexible designs that enabled to fly or otherwise get around in different ways. The researchers also revealed the underlying molecular signals, including Bmp and Ski, that guide the development of those design features.
Attached to the rachis is the feather vane. The vane is the part of the feather made up of many soft barbs that zip together. The researchers report that the vane develops using principles akin to paper cutting. As such, a single epithelial sheet produces a series of diverse, branched designs with individual barbs, each bearing many tiny hooklets that hold the vane together into a plane using a Velcro-like mechanism. Their studies show that gradients in another signaling pathway (Wnt2b) play an important role in the formation of those barbs.
To look back in time, the researchers studied recently discovered amber fossils, allowing them to explore delicate, three-dimensional feather structures. Their studies show that ancient feathers had the same basic architecture but with more primitive characteristics. For instance, adjacent barbs formed the vane with overlapping barbules, without the Velcro-like, hooklet mechanism found in living birds.
"We've learned how a simple skin can be transformed into a feather, how a prototypic feather structure can be transformed into downy, contour, or flight feathers, and how a flight feather can be modulated to adapt to different flight modes required for different living environments," Chuong says. "In every corner and at different morphological scales, we were amazed at how the elegant adaption of the prototype architecture can help different birds to adapt to different new environments."
The researchers say that, in addition to helping to understand how birds have adapted over time, they hope these bioinspired architectural principles they've uncovered can be useful in future technology design. They note that composite materials of the future could contribute toward the construction of light but robust flying drones, durable and resilient wind turbines, or better medical implants and prosthetic devices.
Read more at Science Daily
Ostrich eggshell beads reveal 10,000 years of cultural interaction across Africa
Ostrich eggshell beads are some of the oldest ornaments made by humankind, and they can be found dating back at least 50,000 years in Africa. Previous research in southern Africa has shown that the beads increase in size about 2,000 years ago, when herding populations first enter the region. In the current study, researchers Jennifer Miller and Elizabeth Sawchuk investigate this idea using increased data and evaluate the hypothesis in a new region where it has never before been tested.
Review of old ideas, analysis of old collections
To conduct their study, the researchers recorded the diameters of 1,200 ostrich eggshell beads unearthed from 30 sites in Africa dating to the last 10,000 years. Many of these bead measurements were taken from decades-old unstudied collections, and so are being reported here for the first time. This new data increases the published bead diameter measurements from less than 100 to over 1,000, and reveals new trends that oppose longstanding beliefs.
The ostrich eggshell beads reflect different responses to the introduction of herding between eastern and southern Africa. In southern Africa, new bead styles appear alongside signs of herding, but do not replace the existing forager bead traditions. On the other hand, beads from the eastern Africa sites showed no change in style with the introduction of herding. Although eastern African bead sizes are consistently larger than those from southern Africa, the larger southern African herder beads fall within the eastern African forager size range, hinting at contact between these regions as herding spread. "These beads are symbols that were made by hunter-gatherers from both regions for more than 40,000 years," says lead author Jennifer Miller, "so changes -- or lack thereof -- in these symbols tells us how these communities responded to cultural contact and economic change."
Ostrich eggshell beads tell the story of ancient interaction
The story told by ostrich eggshell beads is more nuanced than previously believed. Contact with outside groups of herders likely introduced new bead styles along with domesticated animals, but the archaeological record suggests the incoming influence did not overwhelm existing local traditions. The existing customs were not replaced with new ones; rather they continued and incorporated some of the new elements.
In eastern Africa, studied here for the first time, there was no apparent change in bead style with the arrival of herding groups from the north. This may be because local foragers adopted herding while retaining their bead-making traditions, because migrant herders possessed similar traditions prior to contact, and/or because incoming herders adopted local styles. "In the modern world, migration, cultural contact, and economic change often create tension," says Sawchuk, "ancient peoples experienced these situations too, and the patterns in cultural objects like ostrich eggshell beads give us a chance to study how they navigated these experiences."
The researchers hope that this work inspires a renewed interest into ostrich eggshell beads, and recommend that future studies present individual bead diameters rather than a single average of many. Future research should also investigate questions related to manufacture, chemical identification, and the effects of taphonomic processes and wear on bead diameter. "This study shows that examining old collections can generate important findings without new excavation," says Miller, "and we hope that future studies will take advantage of the wealth of artifacts that have been excavated but not yet studied."
From Science Daily
Review of old ideas, analysis of old collections
To conduct their study, the researchers recorded the diameters of 1,200 ostrich eggshell beads unearthed from 30 sites in Africa dating to the last 10,000 years. Many of these bead measurements were taken from decades-old unstudied collections, and so are being reported here for the first time. This new data increases the published bead diameter measurements from less than 100 to over 1,000, and reveals new trends that oppose longstanding beliefs.
The ostrich eggshell beads reflect different responses to the introduction of herding between eastern and southern Africa. In southern Africa, new bead styles appear alongside signs of herding, but do not replace the existing forager bead traditions. On the other hand, beads from the eastern Africa sites showed no change in style with the introduction of herding. Although eastern African bead sizes are consistently larger than those from southern Africa, the larger southern African herder beads fall within the eastern African forager size range, hinting at contact between these regions as herding spread. "These beads are symbols that were made by hunter-gatherers from both regions for more than 40,000 years," says lead author Jennifer Miller, "so changes -- or lack thereof -- in these symbols tells us how these communities responded to cultural contact and economic change."
Ostrich eggshell beads tell the story of ancient interaction
The story told by ostrich eggshell beads is more nuanced than previously believed. Contact with outside groups of herders likely introduced new bead styles along with domesticated animals, but the archaeological record suggests the incoming influence did not overwhelm existing local traditions. The existing customs were not replaced with new ones; rather they continued and incorporated some of the new elements.
In eastern Africa, studied here for the first time, there was no apparent change in bead style with the arrival of herding groups from the north. This may be because local foragers adopted herding while retaining their bead-making traditions, because migrant herders possessed similar traditions prior to contact, and/or because incoming herders adopted local styles. "In the modern world, migration, cultural contact, and economic change often create tension," says Sawchuk, "ancient peoples experienced these situations too, and the patterns in cultural objects like ostrich eggshell beads give us a chance to study how they navigated these experiences."
The researchers hope that this work inspires a renewed interest into ostrich eggshell beads, and recommend that future studies present individual bead diameters rather than a single average of many. Future research should also investigate questions related to manufacture, chemical identification, and the effects of taphonomic processes and wear on bead diameter. "This study shows that examining old collections can generate important findings without new excavation," says Miller, "and we hope that future studies will take advantage of the wealth of artifacts that have been excavated but not yet studied."
From Science Daily
Nov 28, 2019
Stem cell therapy helps broken hearts heal in unexpected way
Stem cell therapy helps hearts recover from a heart attack, although not for the biological reasons originally proposed two decades ago that today are the basis of ongoing clinical trials. This is the conclusion of a Nov. 27 study in Nature that shows an entirely different way that heart stem cells help the injured heart -- not by replacing damaged or dead heart cells as initially proposed.
The study reports that injecting living or even dead heart stem cells into the injured hearts of mice triggers an acute inflammatory process, which in turn generates a wound healing-like response to enhance the mechanical properties of the injured area.
Mediated by macrophage cells of the immune system, the secondary healing process provided a modest benefit to heart function after heart attack, according to Jeffery Molkentin, PhD, principal investigator, director of Molecular Cardiovascular Microbiology a Cincinnati Children's Hospital Medical Center and a professor of the Howard Hughes Medical Institute (HHMI).
"The innate immune response acutely altered cellular activity around the injured area of the heart so that it healed with a more optimized scar and improved contractile properties," Molkentin said. "The implications of our study are very straight forward and present important new evidence about an unsettled debate in the field of cardiovascular medicine."
The new paper builds on a 2014 study published by the same research team, also in Nature. As in that earlier study, the current paper shows that injecting c-kit positive heart stem cells into damaged hearts as a strategy to regenerate cardiomyocytes doesn't work. The findings prompted Molkentin and his colleagues to conclude that there is a need to "re-evaluate the current planned cell therapy based clinical trials to ask how this therapy might really work."
An Unexpected Discovery
The study worked with two types of heart stem cells currently used in the clinical trials -- bone marrow mononuclear cells and cardiac progenitor cells. As the researchers went through the process of testing and re-verifying their data under different conditions, they were surprised to discover that in addition to the two types of stem cells, injecting dead cells or even an inert chemical called zymosan also provided benefit to the heart by optimizing the healing process. Zymosan is a substance designed to induce an innate immune response.
Researchers reported that stem cells or zymosan therapies tested in this study altered immune cell responses that significantly decreased the formation of extra cellular matrix connective tissue in the injury areas, while also improving the mechanical properties of the scar itself. The authors concluded: "injected hearts produced a significantly greater change in passive force over increasing stretch, a profile that was more like uninjured hearts."
Molkentin and his colleagues also found that stem cells and other therapeutic substances like zymosan have to be injected directly into the hearts surrounding the area of infarction injury. This is in contrast to most past human clinical trials that for patient safety reasons simply injected stem cells into the circulatory system.
"Most of the current trials were also incorrectly designed because they infuse cells into the vasculature," Molkentin explained. "Our results show that the injected material has to go directly into the heart tissue flanking the infarct region. This is where the healing is occurring and where the macrophages can work their magic."
The researchers also noted an interesting finding involving zymosan, a chemical compound that binds with select pattern recognition receptors to cause an acute innate immune response. Using zymosan to treat injured hearts in mice resulted in a slightly greater and longer-lasting benefit on injured tissues than injecting stem cells or dead cell debris.
Looking to the Future
Molkentin said he and other collaborating scientists will follow up the findings by looking for ways to leverage the healing properties of the stem cells and compounds they tested.
For example, considering how heart stem cells, cell debris and zymosan all triggered an acute innate immune response involving macrophages in the current paper, Molkentin explained they will test a theory that harnesses the selective healing properties of macrophages. This includes polarizing or biologically queuing macrophages to only have healing-like properties.
Read more at Science Daily
The study reports that injecting living or even dead heart stem cells into the injured hearts of mice triggers an acute inflammatory process, which in turn generates a wound healing-like response to enhance the mechanical properties of the injured area.
Mediated by macrophage cells of the immune system, the secondary healing process provided a modest benefit to heart function after heart attack, according to Jeffery Molkentin, PhD, principal investigator, director of Molecular Cardiovascular Microbiology a Cincinnati Children's Hospital Medical Center and a professor of the Howard Hughes Medical Institute (HHMI).
"The innate immune response acutely altered cellular activity around the injured area of the heart so that it healed with a more optimized scar and improved contractile properties," Molkentin said. "The implications of our study are very straight forward and present important new evidence about an unsettled debate in the field of cardiovascular medicine."
The new paper builds on a 2014 study published by the same research team, also in Nature. As in that earlier study, the current paper shows that injecting c-kit positive heart stem cells into damaged hearts as a strategy to regenerate cardiomyocytes doesn't work. The findings prompted Molkentin and his colleagues to conclude that there is a need to "re-evaluate the current planned cell therapy based clinical trials to ask how this therapy might really work."
An Unexpected Discovery
The study worked with two types of heart stem cells currently used in the clinical trials -- bone marrow mononuclear cells and cardiac progenitor cells. As the researchers went through the process of testing and re-verifying their data under different conditions, they were surprised to discover that in addition to the two types of stem cells, injecting dead cells or even an inert chemical called zymosan also provided benefit to the heart by optimizing the healing process. Zymosan is a substance designed to induce an innate immune response.
Researchers reported that stem cells or zymosan therapies tested in this study altered immune cell responses that significantly decreased the formation of extra cellular matrix connective tissue in the injury areas, while also improving the mechanical properties of the scar itself. The authors concluded: "injected hearts produced a significantly greater change in passive force over increasing stretch, a profile that was more like uninjured hearts."
Molkentin and his colleagues also found that stem cells and other therapeutic substances like zymosan have to be injected directly into the hearts surrounding the area of infarction injury. This is in contrast to most past human clinical trials that for patient safety reasons simply injected stem cells into the circulatory system.
"Most of the current trials were also incorrectly designed because they infuse cells into the vasculature," Molkentin explained. "Our results show that the injected material has to go directly into the heart tissue flanking the infarct region. This is where the healing is occurring and where the macrophages can work their magic."
The researchers also noted an interesting finding involving zymosan, a chemical compound that binds with select pattern recognition receptors to cause an acute innate immune response. Using zymosan to treat injured hearts in mice resulted in a slightly greater and longer-lasting benefit on injured tissues than injecting stem cells or dead cell debris.
Looking to the Future
Molkentin said he and other collaborating scientists will follow up the findings by looking for ways to leverage the healing properties of the stem cells and compounds they tested.
For example, considering how heart stem cells, cell debris and zymosan all triggered an acute innate immune response involving macrophages in the current paper, Molkentin explained they will test a theory that harnesses the selective healing properties of macrophages. This includes polarizing or biologically queuing macrophages to only have healing-like properties.
Read more at Science Daily
A new theory for how black holes and neutron stars shine bright
 |
| Black hole illustration. |
Astrophysicists believe that this high-energy radiation -- which makes neutron stars and black holes shine bright -- is generated by electrons that move at nearly the speed of light, but the process that accelerates these particles has remained a mystery.
Now, researchers at Columbia University have presented a new explanation for the physics underlying the acceleration of these energetic particles.
In a study published in the December issue of The Astrophysical Journal, astrophysicists Luca Comisso and Lorenzo Sironi employed massive super-computer simulations to calculate the mechanisms that accelerate these particles. They concluded that their energization is a result of the interaction between chaotic motion and reconnection of super-strong magnetic fields.
"Turbulence and magnetic reconnection -- a process in which magnetic field lines tear and rapidly reconnect -- conspire together to accelerate particles, boosting them to velocities that approach the speed of light," said Luca Comisso, a postdoctoral research scientist at Columbia and first author on the study.
"The region that hosts black holes and neutron stars is permeated by an extremely hot gas of charged particles, and the magnetic field lines dragged by the chaotic motions of the gas, drive vigorous magnetic reconnection," he added. "It is thanks to the electric field induced by reconnection and turbulence that particles are accelerated to the most extreme energies, much higher than in the most powerful accelerators on Earth, like the Large Hadron Collider at CERN."
When studying turbulent gas, scientists cannot predict chaotic motion precisely. Dealing with the mathematics of turbulence is difficult, and it constitutes one of the seven "Millennium Prize" mathematical problems. To tackle this challenge from an astrophysical point of view, Comisso and Sironi designed extensive super-computer simulations -- among the world's largest ever done in this research area -- to solve the equations that describe the turbulence in a gas of charged particles.
"We used the most precise technique -- the particle-in-cell method -- for calculating the trajectories of hundreds of billions of charged particles that self-consistently dictate the electromagnetic fields. And it is this electromagnetic field that tells them how to move," said Sironi, assistant professor of astronomy at Columbia and the study's principal investigator.
Sironi said that the crucial point of the study was to identify role magnetic reconnection plays within the turbulent environment. The simulations showed that reconnection is the key mechanism that selects the particles that will be subsequently accelerated by the turbulent magnetic fields up to the highest energies.
The simulations also revealed that particles gained most of their energy by bouncing randomly at an extremely high speed off the turbulence fluctuations. When the magnetic field is strong, this acceleration mechanism is very rapid. But the strong fields also force the particles to travel in a curved path, and by doing so, they emit electromagnetic radiation.
"This is indeed the radiation emitted around black holes and neutron stars that make them shine, a phenomenon we can observe on Earth," Sironi said.
The ultimate goal, the researchers said, is to get to know what is really going on in the extreme environment surrounding black holes and neutron stars, which could shed additional light on fundamental physics and improve our understanding of how our Universe works.
They plan to connect their work even more firmly with observations, by comparing their predictions with the electromagnetic spectrum emitted from the Crab Nebula, the most intensely studied bright remnant of a supernova (a star that violently exploded in the year 1054). This will be a stringent test for their theoretical explanation.
Read more at Science Daily
Humans co-evolved with immune-related diseases -- and it's still happening
 |
| Immune system word cloud. |
"In the past, people's lifespans were much shorter, so some of these inflammatory and autoimmune diseases that can appear in the second half of life were not so relevant," says first author Jorge Dominguez-Andres (@dominjor), a postdoctoral researcher at Radboud Institute for Molecular Life Science in the Netherlands. "Now that we live so much longer, we can see the consequences of infections that happened to our ancestors."
One of the body's best defenses against infectious diseases is inflammation. Dominguez-Andres and senior author Mihai Netea, a Radboud University immunologist and evolutionary biologist, compiled data from genetics, immunology, microbiology, and virology studies and identified how the DNA from people within different communities commonly infected with bacterial or viral diseases was altered, subsequently allowing for inflammation. While these changes made it more difficult for certain pathogens to infect these communities, they were also associated with the emergence -- over time -- of new inflammatory diseases such as Crohn's disease, Lupus, and inflammatory bowel disease.
"There seems to be a balance. Humans evolve to build defenses against diseases, but we are not able to stop disease from happening, so the benefit we obtain on one hand also makes us more sensitive to new diseases on the other hand," says Dominguez-Andres. "Today, we are suffering or benefiting from defenses built into our DNA by our ancestors' immune systems fighting off infections or growing accustomed to new lifestyles."
For example, the malaria parasite Plasmodium sp. has infected African populations for millions of years. Because of this, evolutionary processes have selected people with DNA that favors resistance to infections by causing more inflammation in the body. In doing so, this has also contributed to making modern Africans prone to developing cardiovascular diseases, such as atherosclerosis, later in life.
Dominguez-Andres and Netea also write about how the early-human ancestors of Eurasians lived in regions still inhabited by Neanderthals and interbred. Today, people with remainders of Neanderthal DNA can be more resistant against HIV-1 and 'staph' infections, but are also more likely to develop allergies, asthma, and hay fever.
The negative side effects of changes in each population's immune systems are a relatively recent finding. "We know a few things about what is happening at the genetic level in our ancestry, but we need more powerful technology. So, next generation sequencing is bursting now and allowing us to study the interplay between DNA and host responses at much deeper levels," says Dominguez-Andres. "So, we are obtaining a much more comprehensive point of view."
These technologies are also revealing how our immune systems are evolving in real time because of modern lifestyle changes. African tribes that still engage in hunting have greater bacterial gut diversity than urbanized African-Americans that eat store-bought foods. Also, changes in hygiene patterns seen in the last two centuries have improved sanitation, drinking water, and garbage collection, and have led to reduced exposure to infectious pathogens relative to previous times. As humans move toward processed foods and stricter hygiene standards, their bodies adapt by developing what researchers call "diseases of civilization," such as type 2 diabetes.
Read more at Science Daily
Subscribe to:
Posts (Atom)