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Comment by Dr. Krishna Kumari Challa on December 3, 2020 at 9:21am

Plant-generated electricity

Comment by Dr. Krishna Kumari Challa on December 3, 2020 at 9:21am

How microorganisms can produce renewable energy for us

We can generate electricity from microorganisms as an alternative to the usual power from water, wind, solar or steam.

Scientists have been studying the ability of microorganisms - the smallest living things on Earth—to produce energy other than for their natural activities for more than a century. This transformation is what scientists call a bioelectrochemical system.

Microbial fuel cell (MFC) is one form of bioelectrochemical system.

This system generally has one anode chamber (negative electrode) and one cathode chamber (positive electrode). MFC works in a similar way to batteries.

Microorganisms decompose organic or inorganic matters (or substrates) in the anode chamber to produce electrons. These electrons flow from anode to cathode via an external circuit made of conductive materials, such as copper-based wires, to generate electricity.

Deciding on the types of microorganism to generate the energy is an influential factor.

To date, the groups of microorganisms that demonstrate the ability to transfer electrons from their cells to the electrodes—called exoelectrogens – are in particular Geobacter and Shewnella.

Geobacter sulfurreducens KN400 can generate up to 3.9 Watts of electricity per square meter (W/m²) of anode area. Shewanella putrefaciens produces up to 4.4 W/m².

For its spaceship, NASA generates energy from Shewanella oneidensis bacteria.

Other microorganisms such as Rhodopseudomonas palustris DX1, Candida melibiosica, Saccharomyces ... also demonstrate exoelectrogenic capabilities.

A new exoelectrogenic microorganism is Desulfuromonas acetexigens.

Exoelectrogens can be obtained from various environments, such as waste water, compost, manure, dirt, river or lake sediments, swamps and marine ecosystems.

https://theconversation.com/this-is-how-microorganisms-can-produce-...

Comment by Dr. Krishna Kumari Challa on December 3, 2020 at 9:05am

Cancer cells 'remove blindfold' to spread

Cunning ways of cancer cells

Cancer cells spread by switching on and off abilities to sense their surroundings, move, hide and grow new tumours, a new study has found.

This sensitivity to their surroundings is the key ability that makes small numbers of cancer cells better at spreading than other cells in a tumour, scientists  discovered.

The researchers developed a new method combining evolutionary biology and artificial intelligence techniques to study the movement and shape of cancer cells in more detail than ever, to learn why some can move more easily to different parts of the body and grow new tumours.

They found some cells displayed an apparent 'awareness' and ability to react to their surroundings, that was previously thought to be lost in of cancer. This means they may be able to adapt their shape to navigate barriers like blood vessel walls or other competing cells far more efficiently in order to replicate elsewhere.

 A phenotypic switch in the dispersal strategy of breast cancer cells selected for metastatic colonisation, Proceedings of the Royal Society B (2020). rspb.royalsocietypublishing.or … .1098/rspb.2020.2523

https://phys.org/news/2020-12-cancer-cells-blindfold.html?utm_sourc...

Comment by Dr. Krishna Kumari Challa on December 3, 2020 at 8:58am

Flightless birds more common globally before human-driven extinctions

There would be at least four times as many flightless bird species on Earth today if it were not for human influences, finds a study by researchers. The study, published in Science Advances, finds that flightlessness evolved much more frequently among birds than would be expected if you only looked at current species. 

Researchers say their findings show how human-driven extinctions have biased our understanding of evolution. 

Human impacts have substantially altered most ecosystems worldwide, and caused the extinction of hundreds of animal species. This can distort evolutionary patterns, especially if the characteristics being studied, such as flightlessness in birds, make species more vulnerable to extinction. We get a biased picture of how evolution really happens.

For the study, the researchers compiled an exhaustive list of all bird species known to have gone extinct since the rise of humans. They identified 581 bird species that went extinct from the Late Pleistocene (126,000 years ago) to the present, almost all of which were likely due to human influences.

The fossils or other records show that 166 of these extinct species lacked the ability to fly. Only 60 flightless bird species survive today.

Birds that cannot fly were much more diverse than previous studies had assumed, the study shows. The findings also confirm that flightless species were also much more likely to go extinct than species that could fly.

"Anthropogenic extinctions conceal widespread evolution of flightlessness in birds" Science Advances (2020). advances.sciencemag.org/lookup … .1126/sciadv.abb6095

https://phys.org/news/2020-12-flightless-birds-common-globally-huma...

Comment by Dr. Krishna Kumari Challa on December 3, 2020 at 8:53am

Continents prone to destruction in their infancy, study finds

Geologists have shed new light on the early history of the Earth through their discovery that continents were weak and prone to destruction in their infancy.

The Earth is our home and over its 4,500,000,000 (4.5 billion) year history has evolved to form the environment we live in and the resources on which we depend.

However, the early history of Earth, covering its first 1.5 billion years remains almost unknown and, consequently, poorly understood.

This was the time of formation of the first continents, the emergence of land, the development of the early atmosphere, and the appearance of primordial life—all of which are the result of the dynamics of our planet's interiors.

Reproducing the conditions of the early Earth in computer-generated numerical models, scientists showed that the release of internal primordial heat, three to four times that of the present-day, caused large melting in the shallow mantle, which was then extruded as magma (molten rock) onto the Earth's surface.

According to the researchers, the shallow mantle left behind by this process was dehydrated and rigid and formed the keels of the first continents.

These results explain that continents remained weak and prone to destruction in their infancy, ~4.5 to ~4.0 billion years ago, and then progressively differentiated and became rigid over the next billion years to form the core of our modern continents. The emergence of these rigid early continents resulted in their weathering and erosion, changing the composition of the atmosphere and providing nutrients to the ocean seeding the development of life.

Thermochemical lithosphere differentiation and the origin of cratonic mantle, Nature (2020). DOI: 10.1038/s41586-020-2976-3 , www.nature.com/articles/s41586-020-2976-3

https://phys.org/news/2020-12-continents-prone-destruction-infancy....

Comment by Dr. Krishna Kumari Challa on December 2, 2020 at 6:40am

Breaking the rules of chemistry unlocks new reaction

Scientists have broken the rules of enzyme engineering to unlock a new method for creating chemical reactions that could unlock a wide range of new applications—from creating new drugs to food production. They show a new method to produce chemical molecules more efficiently through a new one step reaction in the enzyme.

They have demonstrated how a very simple mutation in one of the key residues of a useful enzyme has dramatically expanded its synthetic scope, enabling the use of the mutant variant in the preparation of challenging chemical molecules, as well as natural metabolites that are vital in many biological processes in the body."

Any textbook on enzymes will report on how the catalytic amino acids in any given enzyme family are highly conserved, they are in fact a signature of the type of chemistry an enzyme can do. Variations do occur and in some cases, if the replacing amino acid is similar, both can be found in significant proportion in Nature, but others can be much less common and are found only in a limited number of species.

"In this study theyhave explored an untouched area of enzyme engineering and modified the a key catalytic residue in the active site of an enzyme. Previously it was thought that doing this would cause a loss of activity of the enzyme but we have found this is not the case when this biocatalyst is used in a synthetic direction and in fact challenging but very useful molecules can now be made under mild conditions which could be easily scaled up and replicated commercially for use in a wide range of products.

Martina L. Contente et al, A strategic Ser/Cys exchange in the catalytic triad unlocks an acyltransferase-mediated synthesis of thioesters and tertiary amides, Nature Catalysis (2020). DOI: 10.1038/s41929-020-00539-0

https://phys.org/news/2020-12-chemistry-reaction.html?utm_source=nw...

Comment by Dr. Krishna Kumari Challa on December 2, 2020 at 6:32am

Discovery shines light on how cancer cells could protect themselves

Researchers have found cancer cells can repair their DNA by using 'cables' in their nucleus. The findings open new possibilities for designing future cancer treatments. They  have made an unexpected discovery about cancer cells and how they harness 'cables' in a cell's nucleus to aid DNA repair and replication.

This discovery  revealed an unexpected function for the protein actin. Actin is well known as the protein that interacts with another protein called myosin to make muscles contract. Actin also forms cables inside cells that connect up and function like girders in a building, contributing to the structure and shape of cells.

While scientists have known for decades that actin plays this critical role in the main body of the cell, its role in the cell's control center, the nucleus, has been controversial.

For cancers to grow, cancer cells need to make many new copies of themselves. Every time this happens, the DNA in the cancer cells' nuclei must be replicated.

DNA replication in a cancer cell is like an old car traveling at its top speed—it frequently breaks down and has to get restarted. Cancer chemotherapy exploits this weakness in cancer cells by making the process break down even more frequently in an attempt to destroy them.

Researchers found that when cancer cells encounter problems replicating their DNA, actin cables form inside the nucleus. This allows the nucleus to change shape and increases the ability of the cancer cell to repair its DNA and restart the replication process.

Using advanced super resolution microscopy, the researchers showed that damaged DNA slides along the actin network to move to areas in the nucleus where repair occurs most efficiently. Scientists were previously unaware that cancer cells protected themselves in this way. Critically, this research found that actin performed these unexpected functions in response to treatment with chemotherapy and helped cancer cells resist the treatment.

Noa Lamm et al. Nuclear F-actin counteracts nuclear deformation and promotes fork repair during replication stress, Nature Cell Biology (2020). DOI: 10.1038/s41556-020-00605-6

https://medicalxpress.com/news/2020-12-discovery-cancer-cells.html?...

Comment by Dr. Krishna Kumari Challa on December 2, 2020 at 6:26am

AI predicts which drug combinations kill cancer cells

When healthcare professionals treat patients suffering from advanced cancers, they usually need to use a combination of therapies. In addition to cancer surgery, the patients are often treated with radiation therapy, medication or both.

Medication can be combined with drugs selected for specific cancer cells. Combinatorial drug therapies often improve the effectiveness of the treatment and can reduce the harmful side-effects if the dosage of individual drugs can be reduced. However, experimental screening of drug combinations is very slow and expensive, and therefore, often fails to discover the full benefits of combination therapy. With the help of a new machine-learning method, it is possible to identify the best combinations that selectively kill cancer cells with specific genetic or functional makeup.

developed a machine learning model that accurately predicts how combinations of cancer drugs kill various types of cancer cells. The new AI model was trained with a large set of data obtained from previous studies that investigated the association between drugs and cancer cells. "The model learned by the machine is actually a polynomial function familiar from school mathematics, but a very complex one. The model gives very accurate results. 

Heli Julkunen et al. Leveraging multi-way interactions for systematic prediction of pre-clinical drug combination effects, Nature Communications (2020). DOI: 10.1038/s41467-020-19950-z

https://medicalxpress.com/news/2020-12-ai-drug-combinations-cancer-...

Comment by Dr. Krishna Kumari Challa on December 2, 2020 at 6:17am

New device offers faster way to detect antibiotic-resistant bacteria

Bacterial infections have become one of the biggest health problems worldwide, and a recent study shows that COVID-19 patients have a much greater chance of acquiring secondary bacterial infections, which significantly increases the mortality rate.

Combatting the infections is no easy task, though. When antibiotics are carelessly and excessively prescribed, that leads to the rapid emergence and spread of antibiotic-resistant genes in bacteria—creating an even larger problem. 

One factor slowing down the fight against antibiotic-resistant bacteria is the amount of time needed to test for it. The conventional method uses extracted bacteria from a patient and compares lab cultures grown with and without antibiotics, but results can take one to two days, increasing the mortality rate, the length of hospital stay and overall cost of care.

To effectively treat the infections, we need to select the right antibiotics with the exact dose for the appropriate duration. There's a need to develop an antibiotic-susceptibility testing method and offer effective guidelines to treat these infections.

A new technique 's developed now that relies on the same principles as the batteries: Bacterial electron transfer, a chemical process that certain microorganisms use for growth, overall cell maintenance and information exchange with surrounding microorganisms. Researchers leverage this biochemical event for a new technique to assess the antibiotic effectiveness against bacteria without monitoring the whole bacterial growth.

A medical team would extract a sample from a patient, inoculate the bacteria with various antibiotics over a few hours and then measure the electron transfer rate. A lower rate would mean that the antibiotics are working.

"The hypothesis is that the antiviral exposure could cause sufficient inhibition to the bacterial electron transfer, so the readout by the device would be sensitive enough to show small variations in the electrical output caused by changes in antibiotic effectiveness. The device could provide results about antibiotic resistance in just five hours, which would serve as an important point-of-care diagnostic tool, especially in areas with limited resources.

Yang Gao et al, A simple, inexpensive, and rapid method to assess antibiotic effectiveness against exoelectrogenic bacteria, Biosensors and Bioelectronics (2020). DOI: 10.1016/j.bios.2020.112518

https://phys.org/news/2020-12-device-faster-antibiotic-resistant-ba...

Comment by Dr. Krishna Kumari Challa on December 1, 2020 at 1:13pm

How Bats Can Transmit Viruses | Virus Hunters

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