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Comment by Dr. Krishna Kumari Challa on January 4, 2023 at 9:06am

Self-assembling proteins can store cellular 'memories'

As cells perform their everyday functions, they turn on a variety of genes and cellular pathways. Researchers have now coaxed cells to inscribe the history of these events in a long protein chain that can be imaged using a light microscope.

Cells programmed to produce these chains continuously add building blocks that encode particular cellular events. Later, the ordered protein chains can be labeled with fluorescent molecules and read under a microscope, allowing researchers to reconstruct the timing of the events.

This technique could help shed light on the steps that underlie processes such as memory formation, response to drug treatment, and gene expression.

If the technique could be extended to work over longer time periods, it could also be used to study processes such as aging and disease progression, the researchers say.

Recording of cellular physiological histories along optically readable self-assembling protein chains, Nature Biotechnology (2022). DOI: 10.1038/s41587-022-01586-7

Comment by Dr. Krishna Kumari Challa on December 31, 2022 at 11:09am

Researchers identify 100,000 new types of viruses

A groundbreaking  study has discovered about 100,000 new types of previously unknown viruses , a ninefold increase in the amount of RNA viruses known to science until now. The viruses were discovered in global environmental data from soil samples, oceans, lakes, and a variety of other ecosystems. The researchers believe that the discovery may help in the development of anti-microbial drugs and in protecting against agriculturally harmful fungi and parasites. 

Comment by Dr. Krishna Kumari Challa on December 31, 2022 at 11:03am

Human brain organoids implanted into mouse cortex respond to visual stimuli for first time

 A team of engineers and neuroscientists has demonstrated for the first time that human brain organoids implanted in mice have established functional connectivity to the animals' cortex and responded to external sensory stimuli. The implanted organoids reacted to visual stimuli in the same way as surrounding tissues, an observation that researchers were able to make in real time over several months thanks to an innovative experimental setup that combines transparent graphene microelectrode arrays and two-photon imaging.

Madison N. Wilson, Martin Thunemann, Xin Liu, Yichen Lu, Francesca Puppo, Jason W. Adams, Jeong-Hoon Kim, Mehrdad Ramezani, Donald P. Pizzo, Srdjan Djurovic, Ole A. Andreassen, Abed AlFatah Mansour, Fred H. Gage, Alysson R. Muotri, Anna Devor, Duygu Kuzum. Multimodal monitoring of human cortical organoids implanted in mice reveal functional connection with visual cortex. Nature Communications, 2022; 13 (1) DOI: 10.1038/s41467-022-35536-3

Comment by Dr. Krishna Kumari Challa on December 31, 2022 at 10:11am

Quasicrystal formed during accidental electrical discharge

Quasicrystals, as their name suggests, are crystal-like substances. They possess characteristics not found in ordinary crystals, such as a non-repeating arrangement of atoms. To date, quasicrystals have been found embedded in meteorites and in the debris from nuclear blasts. In this new effort, the researchers found one embedded in a sand dune in Sand Hills, Nebraska.

A team of researchers  has found an incidence of a quasicrystal formed during an accidental electrical discharge.

Study of the quasicrystal showed it had 12-fold, or dodecagonal, symmetry—something rarely seen in quasicrystals. Curious as to how it might have formed and how it ended up in the sand dune, the researchers did some investigating. They discovered that a power line had fallen on the dune, likely the result of a lightning strike. They suggest the electrical surge from either the power line or the lightning could have produced the quasicrystal.

The researchers note that the quasicrystal was found inside of a tubular piece of fulgurite, which they suggest was also formed during the electrical surge due to fusing of melted sand and metal from the power line. 

In looking at the quasicrystal using an electron microscope, the researchers were able to make out its composition. In so doing, they found bits of silicon dioxide glass, which told them that temperatures inside the sand dune during the electrical discharge had to have reached at least 1,710 degrees Celsius. They also found that the quasicrystal had been retrieved from an area of transition between melted aluminum alloy and silicate glass. Their work confirmed that the object they were studying was, indeed, a quasicrystal, and that it had a previously unseen composition.

The researchers conclude that finding a quasicrystal in such a place suggests that others are likely out there, as well, having formed due to lightning strikes or downed power lines. They also suggest their work could lead to techniques to create quasicrystals in the lab.

Luca Bindi et al, Electrical discharge triggers quasicrystal formation in an eolian dune, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2215484119

Comment by Dr. Krishna Kumari Challa on December 31, 2022 at 10:04am

How chronic blood cancer transitions to aggressive disease

A type of chronic leukemia can simmer for many years. Some patients may need treatment to manage this type of blood cancer—called myeloproliferative neoplasms (MPN)—while others may go through long periods of watchful waiting. But for a small percentage of patients, the slower paced disease can transform into an aggressive cancer, called secondary acute myeloid leukemia, that has few effective treatment options. Little has been known about how this transformation takes place.

But now, researchers  have identified an important transition point in the shift from chronic to aggressive leukemia. They have shown that blocking a key molecule in the transition pathway prevents this dangerous disease progression in mice with models of the disease and in mice with tumors sampled from human patients.

Tim Kong et al, DUSP6 mediates resistance to JAK2 inhibition and drives leukemic progression, Nature Cancer (2022). DOI: 10.1038/s43018-022-00486-8

Comment by Dr. Krishna Kumari Challa on December 31, 2022 at 10:01am

Analysis also revealed that by inhibiting NMDA receptors, ketamine administration added noise to gamma frequencies in the post-stimulation 200–700 ms period in one thalamic nucleus and in one layer of the somatosensory cortex. It can be assumed that this observed increase in noise, ie a reduction in the signal-to-noise ratio, also indicates the neurons' impaired ability to process incoming sensory signals.

These findings suggest that psychosis may be triggered by an increase in background noise impairing the function of thalamo-cortical neurons. This, in turn, could be caused by a malfunction of NMDA receptors affecting the balance of inhibition and excitation in the brain. The noise makes sensory signals less defined or pronounced. In addition, this may cause spontaneous outbursts of activity associated with a distorted perception of reality.

"The discovered alterations in thalamic and cortical electrical activity associated with ketamine-induced sensory information processing disorders could serve as biomarkers for testing antipsychotic drugs or predicting the course of disease in patients with psychotic spectrum disorders.

 Yi Qin et al, The psychotomimetic ketamine disrupts the transfer of late sensory information in the corticothalamic network, European Journal of Neuroscience (2022). DOI: 10.1111/ejn.15845

Thomas J. Reilly, Ketamine: Linking NMDA receptor hypofunction, gamma oscillations and psychosis (commentary on Qin et al., 2022), European Journal of Neuroscience (2022). DOI: 10.1111/ejn.15872

Part 2 

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Comment by Dr. Krishna Kumari Challa on December 31, 2022 at 10:00am

Ketamine found to increase brain noise

An international team of researchers found that ketamine, being an NMDA receptor inhibitor, increases the brain's background noise, causing higher entropy of incoming sensory signals and disrupting their transmission between the thalamus and the cortex. This finding may contribute to a better understanding of the causes of psychosis in schizophrenia. An article with the study's findings has been published in the European Journal of Neuroscience.

Schizophrenic spectrum disorders affect approximately one in 300 people worldwide. The most common manifestations of these disorders are perceptual disturbances such as hallucinations, delusions and psychoses. A drug called ketamine can induce a mental state similar to psychosis in healthy individuals. Ketamine inhibits NMDA receptors involved in the transmission of excitatory signals in the brain. An imbalance of excitation and inhibition in the central nervous system can affect the accuracy of sensory perception. Similar changes in the functioning of NMDA receptors are currently thought to be one of the causes of perception disorders in schizophrenia. However, it is still unclear how exactly this process occurs in the brain regions involved.

To find out, neuroscientists 

studied how the brains of laboratory rats on ketamine process sensory signals. The researchers examined beta and gamma oscillations occurring in response to sensory stimuli in the rodent brain's thalamo-cortical system , a neural network connecting the cerebral cortex with the thalamus responsible for the transmission of sensory information from the organs of perception to the brain.

Beta oscillations are brainwaves in the range of 15 to 30 Hz, and gamma waves are those in the range of 30 to 80 Hz. These frequencies are believed to be critical for encoding and integrating sensory information.

In the experiment, rats were implanted with microelectrodes to record the electrical activity in the thalamus and the somatosensory cortex , a region of the brain which is responsible for processing sensory information coming from the thalamus. The researchers stimulated the rats' whiskers (vibrissae) and recorded the brain's responses before and after ketamine administration.

A comparison of the two datasets revealed that ketamine increased the power of beta and gamma oscillations in the cortex and the thalamus even in the resting state before a stimulus was presented, while the amplitude of the beta/gamma oscillations in the 200–700 ms post-stimulus period was significantly lower at all recorded cortical and thalamic sites following ketamine administration.

The post-stimulation time lapse of 200–700 ms is long enough to encode, integrate and perceive the incoming sensory signal. The observed decrease in the power of sensory stimulus-induced oscillations can be associated with impaired perception.

Part 1

Comment by Dr. Krishna Kumari Challa on December 31, 2022 at 9:51am

Researchers discover that soap film on bubbles is cooler than the air around it

A team of researchers has discovered that the film that makes up ordinary soap bubbles is cooler than the surrounding air.

Bubbles exist in a wide variety of environments, from beer glasses to clothes and dish washers to crests on waves. They even exist in tiny environments, like in the space between human teeth. A lot of research has been done with bubbles, much of it focused on controlling them during industrial processes.

 In their work, the researchers created bubbles using ordinary dish soap, water and glycerol. After discovering a temperature difference, the team refocused their efforts to learn more. They tried changing the temperature of the air, the humidity level and also the proportions of the ingredients used to make the bubbles. They found that they were able to make bubbles that were up to 8 degrees Celsius cooler than the air around them. They also found that changing the amount of glycerol impacted the temperature of the resulting bubbles—more of it yielded higher temperatures.

The researchers suggest the cooler films could be the result of evaporation as the bubbles form. They noted also that as the bubbles persisted, their films slowly grew warmer, eventually matching the ambient air temperature. They suggest the large temperature differences they found with some bubbles might have an impact on bubble stability, and conclude that more work is required to find out why the films are cooler and if it might be a useful attribute.

 François Boulogne et al, Measurement of the Temperature Decrease in Evaporating Soap Films, Physical Review Letters (2022). DOI: 10.1103/PhysRevLett.129.268001. On Arxiv: arxiv.org/abs/2212.07104

Comment by Dr. Krishna Kumari Challa on December 30, 2022 at 11:39am

Parental astigmatism may increase risk for child astigmatism

Parental astigmatism may confer an independent and dose-dependent association with child astigmatism, according to a study published online Dec. 21 in JAMA Network Open.

Researchers examined the association between parental astigmatism (an optical system with astigmatism is one where rays that propagate in two perpendicular planes have different foci. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances) and child astigmatism. The analysis included 5,708 familial trios, each comprising a child aged 6 to 8 years and both parents, participating in the Hong Kong Children Eye Study.

The researchers found that astigmatism of ≥1.0 D in both parents was associated with greater odds of refractive astigmatism (RA; odds ratio, 1.62) and corneal astigmatism (CA; odds ratio, 1.94) in the child. When both parents had astigmatism ≥2.0 D, the risk increased further (odds ratios, 3.10 and 4.31, respectively), with higher parental astigmatism conferring higher risks for both RA and CA in children. There was a significant association between each parental astigmatism and corresponding child astigmatism (odds ratios, 0.76, 0.82, 1.70, and 1.33 for maternal RA, paternal RA, maternal CA, and paternal CA, respectively).

"The findings of this cross-sectional study suggest that parental astigmatism may confer an independent and dose-dependent association with child astigmatism," the authors write. "Children with parents with astigmatism should have early eye examinations for timely detection of astigmatism to facilitate age-appropriate vision correction and visual development."

More information: Ka Wai Kam et al, Association of Maternal and Paternal Astigmatism With Child Astigmatism in the Hong Kong Children Eye Study, JAMA Network Open (2022). DOI: 10.1001/jamanetworkopen.2022.47795

Comment by Dr. Krishna Kumari Challa on December 30, 2022 at 11:36am

Gastroesophageal reflux disease raises risk for periodontitis: Study

Patients with gastroesophageal reflux disease (GERD) have an increased risk for periodontitis development, according to a study published online Nov. 19 in Biomedicines.

Researchers conducted a retrospective cohort study to examine the association between GERD and subsequent periodontitis risk using epidemiological data from the Taiwan National Health Insurance Research Database from 2008 to 2018. A total of 20,125 participants with a minimum age of 40 years were included in the GERD group and propensity-matched in a 1:1 ratio with non-GERD participants.

The researchers found that the incidence rate of periodontitis was significantly higher in patients with versus those without GERD (30.0 versus 21.7 per 1,000 person-years; adjusted hazard ratio, 1.36). Patients with GERD had a higher risk for periodontitis in analyses stratified for age (adjusted hazard ratios, 1.31 and 1.42 for age 40 to 54 and 55 to 69 years, respectively), sex (adjusted hazard ratios, 1.40 and 1.33 for men and women, respectively), and presence and absence of comorbidity (adjusted hazard ratios, 1.36 and 1.40, respectively) compared with those without GERD. The risk for periodontitis was increased with an increasing number of emergency room visits among the GERD cohort (one or more versus less than one; adjusted hazard ratio, 5.19).

"Clinicians should pay more attention to the development of periodontitis while caring for patients with GERD," the authors write. "On the other hand, dentists may consider GERD as an etiology of unexplained periodontitis."

More information: Xin Li et al, Risk of Periodontitis in Patients with Gastroesophageal Reflux Disease: A Nationwide Retrospective Cohort Study, Biomedicines (2022). DOI: 10.3390/biomedicines10112980

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