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Comment by Dr. Krishna Kumari Challa on March 11, 2022 at 11:32am

Living in more polluted areas increases risk for poor mental wellbeing

People  who live in more polluted areas, such as near busy roads, are at a higher risk of poor mental wellbeing, new research has found.

The study examined four types of air pollutants—nitrogen dioxide, sulfur dioxide and two types of particulate matter, those with diameters of less than 10 and 2.5µm (micrometers)—and linked these to individual-level health data.

It found a connection between air pollution and people reporting low mental wellbeing affects such as feeling unhappy, being under stress and not being able to concentrate.

It also found a potential link between increasing concentration of sulfur dioxide and particulate matter and elevated scores of poor mental wellbeing for people from a Pakistani/Bangladeshi origin in comparison with British-White people, and for non-UK born individuals in comparison with those born in the UK.

Nitrogen dioxide is mainly produced from traffic exhaust around busy roads, while sulfur dioxide is mainly an industrial type of pollutant. Nitrogen dioxide and sulfur dioxide are gaseous types of pollutants. Particulate matter is related to both traffic exhaust and industrial processes and it is made up of microscopic solid or liquid matter suspended in the atmosphere.

Mary Abed Al Ahad et al, Air pollution and individuals' mental well-being in the adult population in United Kingdom: A spatial-temporal longitudinal study and the moderating effect of ethnicity, PLOS ONE (2022). DOI: 10.1371/journal.pone.0264394

https://phys.org/news/2022-03-polluted-areas-poor-mental-wellbeing....

Comment by Dr. Krishna Kumari Challa on March 11, 2022 at 11:18am

The researchers used global maps of the current growing areas of 25 major crops, including wheat, barley and soybean, which together account for over three quarters of croplands worldwide. They developed a mathematical model to look at all possible ways to distribute this cropland across the globe, while maintaining overall production levels for each crop. This allowed them to identify the option with the lowest environmental impact.

Relocating croplands could drastically reduce the environmental impacts of global food production, Nature Communications Earth & Environment, DOI: 10.1038/s43247-022-00360-6

https://phys.org/news/2022-03-relocating-farmland-clock-twenty-year...

Part 2

Comment by Dr. Krishna Kumari Challa on March 11, 2022 at 11:17am

Relocating farmland could turn back clock twenty years on carbon emissions, say scientists

Scientists have produced a map showing where the world's major food crops should be grown to maximize yield and minimize environmental impact. This would capture large amounts of carbon, increase biodiversity, and cut agricultural use of freshwater to zero.

The reimagined world map of agriculture includes large new farming areas for many major crops around the cornbelt in the mid-western US, and below the Sahara desert. Huge areas of farmland in Europe and India would be restored to natural habitat.

The redesign—assuming high-input, mechanized farming—would cut the carbon impact of global croplands by 71%, by allowing land to revert to its natural, forested state. This is the equivalent of capturing twenty years' worth of our current net CO₂ emissions. Trees capture carbon as they grow, and also enable more carbon to be captured by the soil than when crops are grown in it.

In this optimized scenario, the impact of crop production on the world's biodiversity would be reduced by 87%. This would drastically reduce the extinction risk for many species, for which agriculture is a major threat. The researchers say that croplands would quickly revert back to their natural state, often recovering their original carbon stocks and biodiversity within a few decades.

The redesign would eliminate the need for irrigation altogether, by growing crops in places where rainfall provides all the water they need to grow. Agriculture is currently responsible for around 70% of global freshwater use, and this causes drinking water shortages in many drier parts of the world.

Part 1

Comment by Dr. Krishna Kumari Challa on March 9, 2022 at 10:30am

Bacteria Set Off Viral “Bombs” Inside Neighbors

A study finds some E. coli can deploy a chemical called colibactin to reawaken long-dormant viruses inside bacteria, causing destruction.

Certain E. coli strains can engage in a form of bacterial warfare by producing colibactin, a chemical that can awaken long-dormant viruses inside neighboring cells’ DNA, sometimes resulting in their destruction, according to a new study published February 23 in Nature. 

Throughout a bacterium’s life, bacteriophages—viruses that infect bacteria—insert their DNA into its genome. Typically, these embedded viruses, known as prophages, are harmless and lie dormant unless something triggers their escape. The study reports that E. coli can release colibactin, which damages neighbors’ DNA, triggering the bacteria’s DNA repair system, known as an SOS response. This releases prophage DNA from the bacteria’s genome, causing the virus to regain its virulence. Once these viruses are released from the bacterial genomes, they replicate and burst out of the host microbe, destroying it. They can also begin to infect other, neighboring bacteria—including the bacteria that released the colibactin. 

Colibactin can damage DNA in mammalian cells. In humans, studies suggest that this damage can lead to colon cancer. The new study suggests that the colibactin may be a weapon bacteria use against other bacteria—not human hosts. 

Colibactin isn’t usually lethal to bacteria. Although it caused DNA damage in most bacteria, the study’s authors report that the majority were able to repair the damage. According to Science News, this may be because colibactin is unstable and quickly degrades before it can do irreparable harm. The researchers also found that some bacteria make chemicals that can inhibit colibactin.  

Colibactin may not be acting alone. The team found that the chemical by itself could not reactivate prophages. The researchers were only able to see this effect by combining all of the chemicals the colibactin-producing bacteria produced and delivering them to other bacteria. 

https://www.nature.com/articles/s41586-022-04444-3.epdf?sharing_tok...

https://www.the-scientist.com/news-opinion/bacteria-set-off-viral-b...

Comment by Dr. Krishna Kumari Challa on March 9, 2022 at 10:22am

The Toxic Gas That Provides (Almost) All of Our Food

Comment by Dr. Krishna Kumari Challa on March 9, 2022 at 9:27am

How genes from Mom or Dad shape behaviour

Parenting is not the only way moms and dads impact the behavior of their offspring. Genes matter, too. And although most of our genes are inherited in pairs—one copy from each parent—moms and dads exert their genetic influence in different ways. According to new research  by scientists, each parent has their own impact on hormones and other chemical messengers that control mood and behaviour.

The research team reports that certain groups of cells in the brains of mice rely exclusively on the mother's copy of a gene that is needed to produce essential chemical messengers in the brain called neurotransmitters. In those cells, the father's copy of the gene remains switched off. However, in a different organ, the adrenal gland, certain cells favor the father's copy of the same gene. There, the gene is involved in producing the stress hormone, adrenaline.

After identifying this unexpected switch in parental control of a single gene, the research team went on to demonstrate that it had consequences for behaviour. They found that each parent's gene affected sons and daughters differently: certain decisions in sons were controlled by their mother's gene, whereas fathers had control over some decision-making in daughters.

Evolutionarily speaking, this form of genetic regulation may reflect different parental priorities. The revelation that maternal and paternal alleles of the same gene along the brain-adrenal axis could have disparate, or possibly even antagonistic, phenotypic consequences on behavior is an intriguing observation.

The brain-adrenal axis is a very important part of mammalian biology that controls behavior and affects stress, mood, metabolism and decision-making. This finding is a first step toward understanding how a parent's genes may affect more routine behaviours and related health conditions in people, from mental illnesses and addiction to cancer and Alzheimer's disease.

Christopher Gregg, Noncanonical genomic imprinting in the monoamine system determines naturalistic foraging and brain-adrenal axis functions, Cell Reports (2022). DOI: 10.1016/j.celrep.2022.110500. www.cell.com/cell-reports/full … 2211-1247(22)00236-4

https://phys.org/news/2022-03-parental-genes-mom-dad-behavior.html?...

Comment by Dr. Krishna Kumari Challa on March 9, 2022 at 9:15am

Conversely, female-derived proteins that may help the sperm with functions such as energy metabolism, begin to associate with the sperm immediately after mating, signifying a changing of the guard of proteins. After several days of storage within the FRT, the research team was surprised to discover that nearly 20% of the sperm's proteins had been replaced by female-derived proteins. The female contributions support sperm viability during the prolonged period between copulation and fertilization. This "hand-off" in the maintenance of sperm viability from males to females means that sperm are materially the product of both sexes, and this may be a crucial aspect of reproduction in all internally-fertilizing species, including humans.

By studying the intimate ways in which sperm interact with the FRT during the final stages of functional maturation, the team's research advances understanding of animal fertility and the contributions of each sex to reproductive success.

Erin L. McCullough et al, The life history of Drosophila sperm involves molecular continuity between male and female reproductive tracts, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2119899119

https://phys.org/news/2022-03-biologists-molecular-hand-off-key-rol...

Part 2

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Comment by Dr. Krishna Kumari Challa on March 9, 2022 at 9:14am

Biologists observe a molecular 'hand-off' that plays a key role in reproduction

Everyone considers sperm to be made exclusively by males. Well, it turns out that females also contribute to what makes a sperm a sperm.

In species with internal fertilization, such as humans, the ability for a female to become pregnant and carry a pregnancy to term is dependent upon effective interactions between sperm  and the female reproductive  tract(FRT). When those interactions are defective, the result can be a failed pregnancy. Therefore, understanding the factors that contribute to sperm viability between copulation and fertilization is crucial.

Researchers have been studying the life history of fruit fly (Drosophila melanogaster) sperm to better understand molecular continuity between male and female reproductive tracts—in other words, how the male and female reproductive tracts provide support to keep the sperm viable before fertilization. Their results, published on March 7, 2022 in the journal Proceedings of the National Academy of Sciences (PNAS), shed light on important events that may play a role in infertility that up until now have been poorly understood.

Scientists explored the compositional changes in fruit fly sperm, beginning shortly after they leave the testis, following insemination and finally after protracted storage within the FRT. Fruit flies are powerful model organisms for investigations such as this one because they are easy to culture in the laboratory, have a short generation time and their genetics are richly understood. In their study, the group uncovered that the proteome, or protein makeup, of the sperm undergoes substantial changes after being transferred to the FRT.

For species with internal fertilization, a sperm's developmental "journey"—on the way to its final destination of fertilizing an egg and beginning a new life—transcends both male and female reproductive tracts. After leaving the testis, sperm travel through the male's seminal vesicles and descend through the ejaculatory duct, where they mix with seminal fluid proteins. The team found that many of these seminal proteins are progressively lost after sperm migrate beyond the site of insemination within the FRT.

Part 1

Comment by Dr. Krishna Kumari Challa on March 9, 2022 at 8:56am

Mammalian offspring derived from a single unfertilized egg

A team of researchers affiliated with several institutions in China and one in the U.S. has successfully derived offspring from a single unfertilized mammalian egg—in a mouse. In their paper published in Proceedings of the National Academy of Sciences, the group describes their technique when tested in mice.

Parthenogenesis is the development of embryos from a single unfertilized egg. In nature, it occurs in aphids, fish, reptiles, scorpions, mites and some bees—but not in mammals. In mammals, sexual reproduction involves a fusion of male DNA with female DNA, with the resulting offspring having genetic material from both parents. Prior research has shown that most of the cells in mammals express copies of genes from both parents—but a few do not, instead expressing genes from only the mother or the father. In their work, the researchers took advantage of such exceptions.

Prior research efforts aimed at forcing parthenogenesis in mammals have failed, the researchers note, due to genomic imprinting. They overcame this problem by taking a different approach. Their work involved removing an egg from a mouse and then using CRISPR to edit its genes to mimic the genes a male parent would have contributed during normal fertilization. They then injected an enzyme into the egg to switch on some genes and switch others off to make the genes in the egg resemble those of an egg that has been fertilized by a father. The egg was then implanted into the female's uterus, where it was allowed to grow into a fetus. The researchers repeated this process with several eggs, implanting them all together into a single mouse uterus—mice typically give birth to between eight and 12 pups at a time. All of the pups survived the birth, but only one of them survived to adulthood—and it did well enough to produce offspring as well.

The researchers suggest that parthenogenesis in mammals is achievable, though they acknowledge much more work is required before it can be used in real-world applications. 

Yanchang Wei et al, Viable offspring derived from single unfertilized mammalian oocytes, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2115248119

https://phys.org/news/2022-03-mammalian-offspring-derived-unfertili...

Comment by Dr. Krishna Kumari Challa on March 9, 2022 at 8:47am

Astronomers discover largest molecule yet in a planet-forming disc

Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, researchers  have for the first time detected dimethyl ether in a planet-forming disc. With nine atoms, this is the largest molecule identified in such a disc to date. It is also a precursor of larger organic molecules that can lead to the emergence of life.

Dimethyl ether is an organic molecule commonly seen in star-forming clouds, but had never before been found in a planet-forming disc. The researchers also made a tentative detection of methyl formate, a complex molecule similar to dimethyl ether that is also a building block for even larger organic molecules.

The molecules were found in the planet-forming disc around the young star IRS 48 (also known as Oph-IRS 48) with the help of ALMA, an observatory co-owned by the European Southern Observatory (ESO). IRS 48, located 444 light-years away in the constellation Ophiuchus, has been the subject of numerous studies because its disc contains an asymmetric, cashew-nut-shaped "dust trap". This region, which likely formed as a result of a newly born planet or small companion star located between the star and the dust trap, retains large numbers of millimetre-sized dust grains that can come together and grow into kilometre-sized objects like comets, asteroids and potentially even planets.

Many complex organic molecules, such as dimethyl ether, are thought to arise in star-forming clouds, even before the stars themselves are born. In these cold environments, atoms and simple molecules like carbon monoxide stick to dust grains, forming an ice layer and undergoing chemical reactions, which result in more complex molecules. Researchers recently discovered that the dust trap in the IRS 48 disc is also an ice reservoir, harbouring dust grains covered with this ice rich in complex molecules. It was in this region of the disc that ALMA has now spotted signs of the dimethyl ether molecule: as heating from IRS 48 sublimates the ice into gas, the trapped molecules inherited from the cold clouds are freed and become detectable.

N. G.C. Brunken et al, A major asymmetric ice trap in a planet-forming disk. III. First detection of dimethyl ether, Astronomy & Astrophysics (2022). DOI: 10.1051/0004-6361/202142981

https://phys.org/news/2022-03-astronomers-largest-molecule-planet-f...

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