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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...

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

AI can detect the sound of healthy machines. Can you?

Comment by Dr. Krishna Kumari Challa on March 8, 2022 at 9:43am

For the Earth's lower mantle, this changeover is relevant because some of the sediments on the seafloor, in which material from dead living creatures is deposited, enter the mantle through plate tectonics. Along the subduction zones, these sediments—along with the underlying oceanic crust—are transported to great depths. In this way, the carbon that was stored as organic material in the sediments also reaches the Earth's mantle. There the sediments mix with other rock material from the Earth's mantle and after a certain time, estimated to at least 200–300 million years, rise to the Earth's surface again in other places—for example in the form of kimberlite magmas.

It is remarkable that changes in marine sediments leave such profound traces, because overall, only small amounts of sediment are transported into the depths of the mantle along a subduction zone. This confirms that the subducted rock material in the Earth's mantle is not distributed homogeneously, but moves along specific trajectories.

In addition to carbon, the researchers also examined the isotopic composition of other chemical elements. For example, the two elements strontium and hafnium showed a similar pattern to carbon.

Andrea Giuliani et al, Perturbation of the deep-Earth carbon cycle in response to the Cambrian Explosion, Science Advances (2022). DOI: 10.1126/sciadv.abj1325

https://phys.org/news/2022-03-life-earth-deep-mantle.html?utm_sourc...

Part 2

Comment by Dr. Krishna Kumari Challa on March 8, 2022 at 9:41am

Traces of life in the Earth's deep mantle

The rapid development of fauna 540 million years ago has permanently changed the Earth—deep into its lower mantle. A team of researchers now found traces of this development in rocks from this zone.

It is easy to see that the processes in the Earth's interior influence what happens on the surface. For example, volcanoes unearth magmatic rocks and emit gases into the atmosphere, and thus influence the biogeochemical cycles on our planet.

What is less obvious, however, is that the reverse is also true: what happens on the Earth's surface effect the Earth's interior—even down to great depths. This is the conclusion reached by an international group of researchers  in a new study published in the journal Science Advances. According to this study, the development of life on our planet affects parts of Earth's lower mantle.

In their study, the researchers examined rare diamond-bearing volcanic rocks called kimberlites from different epochs of the Earth's history. These special rocks are messengers from the lowest regions of the Earth's mantle. Scientists measured the isotopic composition of carbon in about 150 samples of these special rocks. They found that the composition of younger kimberlites, which are less than 250 million years old, varies considerably from that of older rocks. In many of the younger samples, the composition of the carbon isotopes is outside the range that would be expected for rocks from the mantle.

The researchers see a decisive trigger for this change in composition of younger kimberlites in the Cambrian Explosion. This relatively short phase—geologically speaking—took place over a period of few tens of million years at the beginning of the Cambrian Epoch, about 540 million years ago. During this drastic transition, almost all of today's existing animal tribes appeared on Earth for the first time. The enormous increase in life forms in the oceans decisively changed what was happening on the Earth's surface. And this in turn affected the composition of sediments at the bottom of the ocean.

Part 1

Comment by Dr. Krishna Kumari Challa on March 8, 2022 at 9:31am

Tiny 'skyscrapers' help bacteria convert sunlight into electricity

Researchers have made tiny 'skyscrapers' for communities of bacteria, helping them to generate electricity from just sunlight and water.

The researchers used 3D printing to create grids of high-rise 'nano-housing' where sun-loving bacteria can grow quickly. The researchers were then able to extract the bacteria's waste electrons, left over from photosynthesis, which could be used to power small electronics.

Other research teams have extracted energy from photosynthetic bacteria, but now the researchers have found that providing them with the right kind of home increases the amount of energy they can extract by over an order of magnitude. The approach is competitive against traditional methods of renewable bioenergy generation and has already reached solar conversion efficiencies that can outcompete many current methods of biofuel generation.

Their results, reported in the journal Nature Materials, open new avenues in bioenergy generation and suggest that 'biohybrid' sources of solar energy could be an important component in the zero-carbon energy mix.

Jenny Zhang, 3D-printed hierarchical pillar array electrodes for high-performance semi-artificial photosynthesis, Nature Materials (2022). DOI: 10.1038/s41563-022-01205-5. www.nature.com/articles/s41563-022-01205-5

https://techxplore.com/news/2022-03-tiny-skyscrapers-bacteria-sunli...

Comment by Dr. Krishna Kumari Challa on March 7, 2022 at 9:08am

It appears that this pocket, specifically built to recognize these fatty acids, gives SARS-CoV-2 an advantage inside the body of infected people, allowing it to multiply so fast. This could explain why it is there, in all variants, including Omicron. Intriguingly, the same feature also provides us with a unique opportunity to defeat the virus, exactly because it is so conserved—with a tailormade antiviral molecule that blocks the pocket.

Kapil Gupta et al, Structural insights in cell-type specific evolution of intra-host diversity by SARS-CoV-2, Nature Communications (2022). DOI: 10.1038/s41467-021-27881-6

Oskar Staufer et al, Synthetic virions reveal fatty acid-coupled adaptive immunogenicity of SARS-CoV-2 spike glycoprotein, Nature Communications (2022). DOI: 10.1038/s41467-022-28446-x

https://medicalxpress.com/news/2022-03-sars-cov-infected-individual...

Part 2

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