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Comment by Dr. Krishna Kumari Challa on June 24, 2020 at 7:44am

Nanomaterials used as broad-spectrum antimicrobial agents for first time

In a significant breakthrough in the battle against antibiotic resistance, a research team from the Indian Institute of Science (IISc) has synthesized a nanomaterial that mimics an enzyme and can disintegrate the cell membranes of a range of disease-causing bacteria.

Antibiotics typically work by interfering with the cellular activities of the bacteria. Over many generations, thanks in large part to misuse and overuse of antibiotics, several bacteria have developed resistance to antibiotics by producing their own enzymes that target the drugs.

The cell membranes of all organisms, including bacteria, have two layers of lipids containing phosphate molecules. "Phospholipid is an essential component of the cell membrane.

Therefore, the researchers decided to target these phospholipids with the help of nanomaterials that would break the bonds holding the membrane bilayer together. These nanomaterials are known as nanozymes. According to the authors, since the nanozymes directly target the chemical integrity of the phospholipids to destroy the cell membrane, bacteria are less likely to be able to develop resistance against them.

To develop this novel compound, the team synthesized a cerium oxide based nanozyme using what is known as a chemical co-precipitation method. In the next step, they carried out a reaction between cerium oxide and sodium polyacrylate in a basic solution to coat the nanoparticles with polymers. The polymer coating allows the nanozyme to disperse onto any surface or material and boosts its activity.

The nanomaterial was then tested in the lab on several potentially pathogenic bacteria such as Salmonella Typhi, Shigella flexneri, Escherichia coli, Vibrio cholerae and Klebsiella pneumoniae, which cause typhoid, gastroenteritis, dysentery, cholera and pneumonia respectively. What the team found was that the nanozyme stopped their growth and subsequently inhibited the formation of biofilm—a densely packed community of bacteria.nanomaterials were able to penetrate even a 10-day old, well-developed biofilm and showed anti-bacterial activity inside the biofilm because of their small size

 Kritika Khulbe et al. Nanoceria-Based Phospholipase-Mimetic Cell Membrane Disruptive Antibiofilm Agents, ACS Applied Bio Materials (2020). DOI: 10.1021/acsabm.0c00363

https://phys.org/news/2020-06-nanomaterials-broad-spectrum-antimicr...

Comment by Dr. Krishna Kumari Challa on June 24, 2020 at 7:26am

Shock and kill approach: New drug candidate reawakens sleeping HIV in hopes of functional cure

https://medicalxpress.com/news/2020-06-drug-candidate-reawakens-hiv...

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https://phys.org/news/2020-06-janus-nanorods-pollutants.html?utm_so...

'Janus' nanorods convert light to heat that can destroy pollutants in water

With a new nanoparticle that converts light to heat, a team of researchers has found a promising technology for clearing water of pollutants.

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https://phys.org/news/2020-06-microscopic-wires-future-molecules.ht...

Microscopic computers: The wires of the future may be made of molecules

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https://phys.org/news/2020-06-fifty-photons-quantum-supremacy.html?...

Fifty perfect photons for 'quantum supremacy'

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**  https://phys.org/news/2020-06-volcanic-eruption-alaska-roman-republ...

Did a volcanic eruption in Alaska help end the Roman republic?

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NASA simulation shows kaleidoscope of sunsets on other worlds

Comment by Dr. Krishna Kumari Challa on June 24, 2020 at 7:19am

Immune system works differently between first and later pregnancies

A mother's immune system is altered during pregnancy to prevent a fetus from being rejected by the body. It is a delicate immunological balance that, if disrupted, could cause a miscarriage or multiple miscarriages. And unfortunately, that balance does too often become disrupted by environmental exposures or physiological changes leading to pregnancy complications.

Researchers now found that a woman's immune system behaves very differently between a first and second pregnancy. First and subsequent pregnancies work very differently and understanding these differences can lead to improved therapies that target the unique immunological perturbations that occur in first and later pregnancies.

The study shows the immune pathways that promote a healthy first pregnancy are not the same pathways that promote later pregnancies.

The authors discuss how pregnancy causes physiological exposure, and often re-exposure, to foreign fetal allo-antigens, which are expressed by the developing fetus. These allo-antigens interact directly with the mother's immune system. The consequences after pregnancy are highly varied, they note.

The researchers found evidence of both alloimmunization (where the immune system attacks) and expanded tolerance phenotypes where it does not. Their data show that pregnancy primes accumulation of fetal-specific maternal CD8+ T cells, and that mothers remember their babies immunologically in that these cells persists as an activated memory pool after she gives birth.

Expression to two proteins, PD-1 and LAG-3 by what are called memory T cells, reminds the cells to again be tolerant of the developing fetus again during subsequent pregnancies. But molecular disruptions that neutralize expression of these proteins unleash the activation of fetal-specific CD8+ T cells, causing miscarriage selectively during subsequent, but not first pregnancies, according to the study

Cell Reports (2020). DOI: 10.1016/j.celrep.2020.107784 , www.cell.com/cell-reports/full … 2211-1247(20)30764-6

https://medicalxpress.com/news/2020-06-immune-differently-pregnanci...

Comment by Dr. Krishna Kumari Challa on June 24, 2020 at 7:14am

How myxobacteria distinguish self from non-self

A fundamental question in biology is how individual cells within a multicellular organism interact to coordinate diverse processes.

Scientists studied myxobacteria—common soil microbes that prey off other microbes for food—and posed the question: "How do cells from a diverse environment recognize other cells as related or clonal to build social groups and a multicellular organism?"

Myxobacteria assemble a multicellular organism by cobbling together cells from their environment. This is in contrast to plants and animals, where gametes fuse to create a unique cell, which, upon clonal expansion, creates a multicellular organism. The ability of myxobacteria to create multicellular organisms is remarkable, given that soil is considered to be the most diverse environment on the planet, wherein a small sample can consist of tens of thousands of microbial species.

Multicellularity is a difficult way of life to evolve and maintain, because cells are the smallest unit of life, and there is selective pressure for them to exploit their environment, including other cells, for their own benefit," he explains. "For example, cancer cells do this and are constantly arising in our own body. Fortunately, our immune system recognizes them as non-self and eliminates them. Our system works in an analogous manner.

The work in the PNAS paper showed that Myxococcus xanthus expresses a highly variable cell surface receptor called TraA. Cells use these receptors, which have many different sequences or alleles in populations, to recognize other cells as possible clonemates or as self. If the other cells bear identical TraA receptors, they interact. This results in the transient fusion of cells where they exchange cellular components, such as proteins and lipids, but no DNA. Included in this cargo are highly variable toxin proteins.

Thus, if the other cells are true clonemates, they have genetically encoded immunity to those toxins. But if they are divergent cells that happen to have compatible TraA receptors, but are not clonemates, they will be killed by toxin transfer. 

Christopher N. Vassallo et al, Rapid diversification of wild social groups driven by toxin-immunity loci on mobile genetic elements, The ISME Journal (2020). DOI: 10.1038/s41396-020-0699-y

https://phys.org/news/2020-06-myxobacteria-ability-distinguish-non-...

Comment by Dr. Krishna Kumari Challa on June 24, 2020 at 6:56am

Quantum physics provides a way to hide ignorance

https://phys.org/news/2020-06-quantum-physics.html?utm_source=nwlet...

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https://phys.org/news/2020-06-isotope-mendelevium-.html?utm_source=...

Introducing a new isotope: Mendelevium-244

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Comment by Dr. Krishna Kumari Challa on June 24, 2020 at 6:41am

How an intelligent alien civilization can exploit a black hole for energy

Experiment confirms 50-year-old theory describing how an alien civilization could exploit a black hole

A 50-year-old theory that began as speculation about how an alien civilization could use a black hole to generate energy has been experimentally verified for the first time in a Glasgow research lab.

In 1969, British physicist Roger Penrose suggested that energy could be generated by lowering an object into the black hole's ergosphere—the outer layer of the black hole's event horizon, where an object would have to move faster than the speed of light in order to remain still.

Penrose predicted that the object would acquire a negative energy in this unusual area of space. By dropping the object and splitting it in two so that one half falls into the black hole while the other is recovered, the recoil action would measure a loss of negative energy—effectively, the recovered half would gain energy extracted from the black hole's rotation. The scale of the engineering challenge the process would require is so great, however, that Penrose suggested only a very advanced, perhaps alien, civilisation would be equal to the task.

Two years later, another physicist named Yakov Zel'dovich suggested the theory could be tested with a more practical, earthbound experiment. He proposed that "twisted" light waves, hitting the surface of a rotating metal cylinder turning at just the right speed, would end up being reflected with additional energy extracted from the cylinder's rotation thanks to a quirk of the rotational doppler effect.

But Zel'dovich's idea has remained solely in the realm of theory since 1971 because, for the experiment to work, his proposed metal cylinder would need to rotate at least a billion times a second—another insurmountable challenge for the current limits of human engineering.

https://phys.org/news/2020-06-year-old-theory-alien-civilization-ex...
Marion Cromb et al. Amplification of waves from a rotating body, Nature Physics (2020). DOI: 10.1038/s41567-020-0944-3

Comment by Dr. Krishna Kumari Challa on June 23, 2020 at 11:40am

What are antibodies and how they work

Comment by Dr. Krishna Kumari Challa on June 23, 2020 at 9:18am

Genetic Diversity of Malaria in a Single Mosquito Bite May Be Huge

New blood tests help to track disease-causing Plasmodium strains

https://www.scientificamerican.com/article/genetic-diversity-of-mal...

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https://theconversation.com/autoimmune-diseases-we-discovered-how-t...

Autoimmune diseases: scientists discovered how to turn white blood cells from attacking the body to protecting it

Comment by Dr. Krishna Kumari Challa on June 23, 2020 at 8:34am

In a new article, scientists provide an exhaustive, evidence-based review of how COVID-19 droplets from infected patients spread through the air and describe how health care professionals can protect themselves. This Pulmonary Perspective is published online in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

In "Coughs and Sneezes: Their Role in Transmission of Respiratory Viral...

 Research recommendations for reducing the transmission of respiratory tract infections, which are consistent with guidelines from the Centers for Disease Control and Prevention. They include :

• Avoid procedures that irritate airways and provoke violent coughing and try to reduce exposure to infectious aerosol.
• If possible, health care providers should stay six feet away from infected patients, especially when the patient is coughing or sneezing.
• When using a mechanical ventilator, institute barriers to filter the virus or reduce virus dispersion by placing a filter at the exhalation port of the ventilator or connecting a filter to the oxygen mask.
• For spontaneously breathing patients, placing a surgical mask on the patient's face or using tissue to cover his or her mouth, especially during coughing, sneezing or talking, may reduce the dispersion distance or viral load.
• Employ PPE for health care providers.
• While, ideally, infected patients should be in single rooms to prevent droplet dispersion, it is acceptable for two patients with the same infection that is spread by respiratory droplets to be in the same room.

Coughs and sneezes create respiratory droplets of variable size that spread respiratory viral infections. Because these droplets are forcefully expelled, they are dispersed in the environment and can be exhaled by a susceptible host. While most respiratory droplets are filtered by the nose or deposit in the oropharynx, the smaller droplet nuclei become suspended in room air and individuals farther away from the patient may inhale them.

These finer particles are carried by the airstream into the lungs, where their site of deposition depends on their size and shape and is governed by various mechanisms. The respiratory transmission of the SARS-CoV-2 virus that causes COVID-19 is mainly by respiratory droplets. Appropriate protective measures are necessary to prevent virus transmission in various settings.

https://www.atsjournals.org/doi/abs/10.1164/rccm.202004-1263PP

Comment by Dr. Krishna Kumari Challa on June 23, 2020 at 8:19am

Switch off your engine, it’s not hard: how to cut your fuel bill, clear the air and reduce emissions

https://theconversation.com/switch-off-your-engine-its-not-hard-how...

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