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Comment by Dr. Krishna Kumari Challa on January 10, 2021 at 10:40am

Rare quadruple-helix DNA found in living human cells with glowing probes

New probes allow scientists to see four-stranded DNA interacting with molecules inside living human cells, unraveling its role in cellular processes.

DNA usually forms the classic double helix shape of two strands wound around each other. While DNA can form some more exotic shapes in test tubes, few are seen in real living cells.

However, four-stranded DNA, known as G-quadruplex, has recently been seen forming naturally in human cells. Now, in new research published today in Nature Communications, a team led by Imperial College London scientists have created new probes that can see how G-quadruplexes are interacting with other molecules inside living cells.

G-quadruplexes are found in higher concentrations in cancer cells, so are thought to play a role in the disease. The probes reveal how G-quadruplexes are 'unwound' by certain proteins, and can also help identify molecules that bind to G-quadruplexes, leading to potential new drug targets that can disrupt their activity.

A different DNA shape will have an enormous impact on all processes involving it—such as reading, copying, or expressing genetic information.

"Evidence has been mounting that G-quadruplexes play an important role in a wide variety of processes vital for life, and in a range of diseases, but the missing link has been imaging this structure directly in living cells.

They used a chemical probe called DAOTA-M2, which fluoresces (lights up) in the presence of G-quadruplexes, but instead of monitoring the brightness of fluorescence, they monitored how long this fluorescence lasts. This signal does not depend on the concentration of the probe or of G-quadruplexes, meaning it can be used to unequivocally visualize these rare molecules.

Peter A. Summers et al. Visualizing G-quadruplex DNA dynamics in live cells by fluorescence lifetime imaging microscopy, Nature Communications (2021). DOI: 10.1038/s41467-020-20414-7

https://phys.org/news/2021-01-rare-quadruple-helix-dna-human-cells....

Comment by Dr. Krishna Kumari Challa on January 10, 2021 at 9:56am

Scientists discover virus-like particles in Bryozoa

Scientists from Russia, Austria, and the USA have discovered virus-like particles in the bacterial symbionts of Bryozoa—a phylum of colonial aquatic invertebrates—filter-feeders dominating in many bottom ecosystems.

Some of the virus-like particles resemble red blood cells, while others have a sea-urchin-like appearance. Although viruses have never been reported inside symbiotic bacteria in bryozoans, scientists suggest that this 'matryoshka doll' may have a prominent effect on the bacterial hosts.

A. E. Vishnyakov et al, First evidence of virus-like particles in the bacterial symbionts of Bryozoa, Scientific Reports (2021). DOI: 10.1038/s41598-020-78616-4

https://phys.org/news/2021-01-scientists-virus-like-particles-bryoz...

Comment by Dr. Krishna Kumari Challa on January 10, 2021 at 9:40am

Entangling electrons with heat

A joint group of scientists from various countries has demonstrated that temperature difference can be used to entangle pairs of electrons in superconducting structures.

 The team has shown that the thermoelectric effect provides a new method for producing entangled electrons in a new device.

In quantum computing, entanglement is used to fuse individual quantum systems into one, which exponentially increases their total computational capacity. "Entanglement can also be used in quantum cryptography, enabling the secure exchange of information over long distances.

Given the significance of entanglement to quantum technology, the ability to create entanglement easily and controllably is an important goal for researchers.

The researchers designed a device where a superconductor was layered withed graphene and metal electrodes. Superconductivity is caused by entangled pairs of electrons called "cooper pairs." Using a temperature difference, they cause them to split, with each electron then moving to different normal metal electrode. "The resulting electrons remain entangled despite being separated for quite long distances.

Thermoelectric current in a graphene Cooper pair splitter, Nature Communications (2021). DOI: 10.1038/s41467-020-20476-

https://phys.org/news/2021-01-entangling-electrons.html?utm_source=...

Comment by Dr. Krishna Kumari Challa on January 10, 2021 at 9:36am

Bacteria can tell the time

Humans have them, so do other animals and plants. Now research reveals that bacteria too have internal clocks that align with the 24-hour cycle of life on Earth.

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The research answers a long-standing biological question and could have implications for the timing of drug delivery, biotechnology, and how we develop timely solutions for crop protection.

Biological clocks or circadian rhythms are exquisite internal timing mechanisms that are widespread across nature enabling living organisms to cope with the major changes that occur from day to night, even across seasons.

Existing inside cells, these molecular rhythms use external cues such as daylight and temperature to synchronise biological clocks to their environment. It is why we experience the jarring effects of jet lag as our internal clocks are temporarily mismatched before aligning to the new cycle of light and dark at our travel destination.

A growing body of research in the past two decades has demonstrated the importance of these molecular metronomes to essential processes, for example sleep and cognitive functioning in humans, and water regulation and photosynthesis in plants.

Although bacteria represent 12% biomass of the planet and are important for health, ecology, and industrial biotechnology, little is known of their 24hr biological clocks.

Previous studies have shown that photosynthetic bacteria which require light to make energy have biological clocks.

But free-living non photosynthetic bacteria have remained a mystery in this regard.

In this international study researchers detected free running circadian rhythms in the non-photosynthetic soil bacterium Bacillus subtilis.

 A circadian clock in a non-photosynthetic prokaryote, Science Advances (2021). advances.sciencemag.org/lookup … .1126/sciadv.abe2086

https://phys.org/news/2021-01-bacteria.html?utm_source=nwletter&...

Comment by Dr. Krishna Kumari Challa on January 10, 2021 at 9:33am

Skin cells protect their DNA from bumps and bruises with a jello-like response

Cells’ responses to microscopic pushes and pulls prevent cancers from forming

https://massivesci.com/articles/skin-cells-mechanics-forces/?utm_so...

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Deadly parasites create unique cellular structures to survive

Scientists have solved a key parasitic puzzle, revealing the unique and complex structures toxoplasmosis and malaria parasites make in order to survive in different hosts.

The new work details how certain parasites can create unique cellular structures to control how they create energy and thus survive in different hosts.

Malaria and toxoplasmosis, both potentially deadly diseases, are caused by similar parasites which organize themselves to exploit their host's energy resources in order to infect and transmit to new hosts. However, until now, scientists didn't fully understand the detailed mechanisms behind this process.

In this new research, researchers have solved a parasitic puzzle at the heart of how these deadly pathogens are able to survive in different hosts in order for them to transmit onwards.

In order to survive these parasites rely on resources available in their host—for toxoplasmosis it is animals and humans, while for malaria this includes also insects. This means that in order to survive, to infect the host and to transmit between hosts, these parasites have to be flexible in how they create energy based on what is available to them.

Scientists studied a vital energy-producing machine within the parasite called ATP synthase. In addition to making energy, ATP synthase machines can also come together into large structures that together shape the mitochondrial membrane, controlling the rate of energy production, and key to its survival. Researchers found that, in these parasites, the ATP synthase machines were able to make complex and unique pentagonal pyramid structures, unlike anything produced by the same systems in their human host.

Alexander Mühleip et al. ATP synthase hexamer assemblies shape cristae of Toxoplasma mitochondria, Nature Communications (2021). DOI: 10.1038/s41467-020-20381-z

https://phys.org/news/2021-01-deadly-parasites-unique-cellular-surv...

Comment by Dr. Krishna Kumari Challa on January 10, 2021 at 9:30am

Identical twins are not so identical

Scientists have quantified the small genetic differences between monozygotic twins. Researchers analysed the DNA of 381 identical twin pairs (and 2 triplets) and found thousands of mutations that appeared in one twin and not the other. Twins differed on average by 5.2 early developmental mutations, which occurred after the initial formation of the zygote. Some siblings differed by dozens of mutations, and some did not differ at all. “The implication is that we have to be very careful when we are using twins as a model” .

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Identical twins are not so identical, study suggests

Research finds they differ by an average of 5.2 early mutations, adding new perspective to nature-versus-nurture debates

https://www.nature.com/articles/s41588-020-00755-1

Comment by Dr. Krishna Kumari Challa on January 10, 2021 at 9:28am

The Riemann Hypothesis, Explained

Comment by Dr. Krishna Kumari Challa on January 7, 2021 at 12:40pm

Quicksand Science: Why It Traps, How to Escape

If stumbling into quicksand ranks on your list of worries, don't panic. A new study suggests that quicksand is not as deadly as it may seem.

https://www.nationalgeographic.com/news/2005/9/quicksand-science-wh...

Comment by Dr. Krishna Kumari Challa on January 7, 2021 at 9:29am

How Earth's oddest mammal got to be so bizarre

Often considered the world's oddest mammal, Australia's beaver-like, duck-billed platypus exhibits an array of bizarre characteristics: it lays eggs instead of giving birth to live babies, sweats milk, has venomous spurs and is even equipped with 10 sex chromosomes. Now, an international team of researchers led by University of Copenhagen has conducted a unique mapping of the platypus genome and found answers regarding the origins of a few of its stranger features.

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It lays eggs, but nurses, it is toothless, has a venomous spur, has webbed feet, fur that glows and has 10 sex chromosomes.

The complete genome has provided us with the answers to how a few of the platypus' bizarre features emerged. At the same time, decoding the genome for platypus is important for improving our understanding of how other mammals evolved—including us humans. It holds the key as to why we and other eutheria mammals evolved to become animals that give birth to live young instead of egg-laying animals.

Yang Zhou et al. Platypus and echidna genomes reveal mammalian biology and evolution, Nature (2021). DOI: 10.1038/s41586-020-03039-0

Paula Spaeth Anich et al. Biofluorescence in the platypus (Ornithorhynchus anatinus), Mammalia (2020). DOI: 10.1515/mammalia-2020-0027

https://phys.org/news/2021-01-earth-oddest-mammal-bizarre.html?utm_...

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Comment by Dr. Krishna Kumari Challa on January 7, 2021 at 9:22am

How an embryo tells time

It is estimated that the majority of pregnancies that fail do so within the first seven days after fertilization, before the embryo implants into the uterus. In this time period, a complicated cascade of events occurs with precise timing. One particularly important process is called polarization, when the individual cells that make up the embryo become asymmetrical. Polarization occurs at 2.5 days for mouse embryos and 3.5 days for human embryos.

Just as musicians playing together in an orchestra need to play at the right time—not early, not late—the timing of polarization is critical for proper embryonic function. Studies have shown that if polarization occurs too early or too late, the embryo is less likely to develop properly. Embryos obviously cannot look at a clock to know when it is time to polarize, so how do they "know" when it is time?

A new study has uncovered the signals that mouse embryos follow to initiate polarization. Understanding the molecular mechanisms underlying embryonic development is critical for understanding how life begins.

The first is the zygotic genome activation, or ZGA, which represents the initial "awakening" of the embryonic DNA after it has combined from sperm and egg, with certain genes for development flipped on like a dormant computer booting up. A flood of molecular activity follows ZGA, and during that period, the team found, three specific factors—protein-based structures called Tfap2c, Tead4, and RhoA—work together to initiate polarization.

This research is the first to identify the necessary and sufficient conditions that drive cell polarization. Once the team had identified the three factors that initiate polarization, they turned their focus to the polarization process itself.

 Meng Zhu et al. Developmental clock and mechanism of de novo polarization of the mouse embryo, Science (2020). DOI: 10.1126/science.abd2703

https://phys.org/news/2021-01-embryo.html?utm_source=nwletter&u...

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