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Comment by Dr. Krishna Kumari Challa on October 28, 2023 at 9:24am

Inside CERN’s ‘antimatter factory’ creating antihydrogen

Comment by Dr. Krishna Kumari Challa on October 27, 2023 at 7:34am

Mimics human tissue, fights bacteria: new biomaterial

Scientists have created a new material that could change the way human tissue can be grown in the lab and used in medical procedures.

The new material belongs to a family of substances called hydrogels, the essence of life’s ‘squishy’ substances found in all living things, such as cartilage in animals and in plants like seaweed. The properties of hydrogels make them very useful in biomedical research because they can mimic human tissue, allowing cells to grow in a laboratory.

There are also human-made hydrogels that are used in a broad range of commodity products ranging from food and cosmetics to contact lenses and absorbent materials, and more recently in medical research to seal wounds and replace damaged tissue. While they might function adequately as space fillers that encourage tissue growth, synthetic hydrogels fall short in recreating the complex properties of real human tissue.

But in a research paper published today in Nature Communications, scientists describe how a new lab-made hydrogel behaves like natural tissue, with a number of surprising qualities that have implications for medical, food and manufacturing technology.

The hydrogel material is made from very simple, short peptides, which are the building blocks of proteins. The material is bioactive, which means that encapsulated cells behave as if they are living in natural tissue. At the same time, the material is antimicrobial, meaning that it will prevent bacterial infections. This combination lands it in the sweet spot for materials that might be useful in medicine. The material is also self-healing, which means that it will reform after being squished, fractured, or after being expelled from a syringe. This makes it ideal for 3D bioprinting, or as an injectable material for medicine.

https://www.nature.com/articles/s41467-023-41907-1

Comment by Dr. Krishna Kumari Challa on October 25, 2023 at 10:01am

Biological fingerprints in soil show where diamond-containing ore is buried

Researchers have identified buried kimberlite, the rocky home of diamonds, by testing the DNA of microbes in the surface soil.

These "biological fingerprints" can reveal which minerals are buried tens of meters below Earth's surface without having to drill. The researchers believe it is the first use of modern DNA sequencing of microbial communities in the search for buried minerals.

The research published in Communications Earth and Environment represents a new tool for mineral exploration, where a full toolbox could save prospectors time and a lot of money.

When ore interacts with soil, it changes the communities of microbes in the soil. The researchers tested this in the lab, introducing kimberlite to soil microbes and watching how they changed in number and species.

Using these "indicator" microbes and their DNA sequences, the team tested the surface soil at an exploration site in the Northwest Territories where kimberlite had previously been confirmed through drilling. They found 59 of the 65 indicators were present in the soil, with 19 present in high numbers directly above the buried ore. They also identified new indicator microbes to add to their set.

Using this set, they tested the surface soil at a second site in the Northwest Territories where they suspected kimberlite was present, and precisely located the topological outline and location of kimberlite buried tens of meters beneath the Earth's surface. This showed that indicators from one site could predict the location at another site. In future, exploration teams could build up a database of indicator species and test an unknown site to find out if kimberlite deposits are buried beneath the soil.

The researchers evaluated their technique against another technique known as geochemical analysis, which involves testing elements in the soil to identify the minerals beneath. The microbes were more precise when it came to identifying the location of buried ore.

Rachel L. Simister et al, DNA sequencing, microbial indicators, and the discovery of buried kimberlites, Communications Earth & Environment (2023). DOI: 10.1038/s43247-023-01020-z

Comment by Dr. Krishna Kumari Challa on October 23, 2023 at 10:04am

Comment by Dr. Krishna Kumari Challa on October 23, 2023 at 9:30am

Two probiotics identified as promising hypertension treatments

An estimated 40% of the global adult population have high blood pressure, or hypertension, which puts people at risk of cardiovascular disease and other dangerous health conditions. Recent studies suggest that probiotics may offer a protective effect, but researchers have a limited understanding of why shaping the gut microbiota can regulate blood pressure.

A study published in mSystems adds two new strains to the list of potential antihypertensive probiotics.

In experiments on hypertensive mice, treatment with the two probiotics, Bifidobacterium lactis and Lactobacillus rhamnosus, returned blood pressure to normal levels. The researchers also tracked how those probiotics altered the animals' gut microbial mix over 16 weeks, identifying specific microbes and metabolic pathways that may help explain the protective effect.

Accumulated evidence supports an antihypertensive effect of probiotics and probiotic fermented foods in both in vitro and in vivo experiments

Previous studies have connected the rising rates of hypertension worldwide to increasing consumption of sugar. It likely boosts blood pressure through many mechanisms—increased insulin resistance or salt retention, for example—but in recent years researchers have investigated sugar's effect on the gut microbiome, as well.

In the new study, the researchers tested the two probiotic strains on mice that developed high blood pressure after consuming water mixed with fructose. Over 16 weeks, they measured the animals' blood pressures every four weeks. They found that fructose-fed mice that received either probiotic showed significantly lower blood pressures than those fed a high fructose diet and not treated with probiotics.

The researchers used shotgun metagenomic sequencing to probe connections between the altered gut microbiota and the change in blood pressure. They found that a high-fructose diet in the mice led to an increase in Bacteroidetes and a decrease in Firmicutes bacteria; however, treatment with probiotics returned those populations to those found in the control group. In addition, the analysis identified new microbial signatures associated with blood pressure: Increased levels of Lawsonia and Pyrolobus bacteria, and reduced levels of Alistipes and Alloprevotella, were associated with lower blood pressure.

 mSystems (2023). journals.asm.org/doi/10.1128/msystems.00331-23

Comment by Dr. Krishna Kumari Challa on October 22, 2023 at 9:03am

The encounter between Neanderthals and Homo sapiens as told by their genomes

 About 40,000 years ago, Neanderthals, who had lived for hundreds of thousands of years in the western part of the Eurasian continent, gave way to Homo sapiens, who had arrived from Africa. This replacement was not sudden, and the two species coexisted for a few millennia, resulting in the integration of Neanderthal DNA into the genome of Homo sapiens.

Researchers  have analyzed the distribution of the portion of DNA inherited from Neanderthals in the genomes of humans (Homo sapiens) over the last 40,000 years. These statistical analyses revealed subtle variations in time and geographical space. This work, published in the journal Science Advances, helps us to understand the common history of these two species.

Thanks to genome sequencing and comparative analysis, it is established that Neanderthals and Homo sapiens interbred and that these encounters were sometimes fruitful, leading to the presence of about 2% of DNA of Neanderthal origin in present-day Eurasians. However, this percentage varies slightly between regions of Eurasia, since DNA from Neanderthals is somewhat more abundant in the genomes of Asian populations than in those of European populations.

One hypothesis to explain this difference is that natural selection would not have had the same effect on genes of Neanderthal origin in Asian and European populations.

Another new theory suggests that such differences could be explained by migratory flows: when a migrant population hybridizes with a local population, in their area of cohabitation, the proportion of DNA of the local population tends to increase with distance from the point of departure of the migrant population.

In the case of Homo sapiens and Neanderthals, the hypothesis is that the further one moves away from Africa, Homo sapiens' point of origin, the greater the proportion of DNA from Neanderthal, a population mainly located in Europe. To test this hypothesis, the authors used a database made available by Harvard Medical School that includes more than 4,000 genomes from individuals who have lived in Eurasia over the past 40 millennia.

Statistical analyses revealed that, in the period following the dispersal of Homo sapiens from Africa, the genomes of Paleolithic hunter-gatherers who lived in Europe contained a slightly higher proportion of DNA of Neanderthal origin than the genomes of those who lived in Asia. This result is contrary to the current situation but in agreement with paleontological data, since the presence of Neanderthals was mainly reported in western Eurasia (no Neanderthal bones have been discovered further east than the Altai region of Siberia).

Subsequently, during the transition to the Neolithic, i.e. the transition from the hunter-gatherer lifestyle to the farmer lifestyle, 10,000 to 5,000 years ago, the study shows a decline in the proportion of DNA of Neanderthal origin in the genomes of European populations, resulting in a slightly lower percentage than that of Asian populations (as currently observed).

This study shows that the analysis of ancient genomes, coupled with archaeological data, makes it possible to trace different stages in the history of hybridized species.

Claudio S. Quilodrán, Jérémy Rio, Alexandros Tsoupas, Mathias Currat. Past human expansions shaped the spatial pattern of Neanderthal ancestry. Science Advances, 2023; 9 (42) DOI: 10.1126/sciadv.adg9817

Comment by Dr. Krishna Kumari Challa on October 21, 2023 at 11:47am

The researchers demonstrated that there were considerable differences in gene expression in the intestine, brain and placenta of the fetuses of germ-free and normal mouse dams.

In the gut, genes associated with the immune system and host–microbe interactions were less active in the fetuses of germ-free dams. There were significant differences in the expression of genes in the brain associated with the development and functioning of the nervous system. In the placenta, there were differences in the expression of several important genes that regulate pregnancy.

The differences were more extensive in male fetuses, indicating that they may be more sensitive to the effects of the maternal microbiota, at least in mice.

The researchers discovered that the expression of many important genes was associated with the concentration of metabolites likely to be modulated by the maternal microbiota. These metabolites were absent in the fetuses of germ-free dams, or occurred at least at significantly lower concentrations.

Aleksi Husso et al, Impacts of maternal microbiota and microbial metabolites on fetal intestine, brain, and placenta, BMC Biology (2023). DOI: 10.1186/s12915-023-01709-9

Part 2

Comment by Dr. Krishna Kumari Challa on October 21, 2023 at 11:46am

Maternal microbiota can affect fetal development

In a new study, significant differences in the gene activity of the faetal intestine, brain and placenta were identified, depending on the microbes in the mother's body and the compounds produced by them. The findings indicate that maternal microbes are important to her offspring's development and health.

The microbiota of the mother, or dam, is thought to be important for the development and health of her offspring. However, so far little is known about how interactions with the microbiota begin and what the mechanisms of action are.

A collaborative study investigated how the maternal microbiota affects fetal development by comparing the fetuses of normal and germ-free mouse dams living in a sterile environment. The researchers measured gene expression and the concentrations of small-molecular compounds, or metabolites, in the fetal intestine, brain and placenta.

This new  study sheds light on the significance of the microbiota and the mechanisms by which the microbiota affects individual development and pregnancy. Researchers identified previously unknown compounds in the fetus, which are likely to be microbial, and which can be important for individual development.

Part 1

Comment by Dr. Krishna Kumari Challa on October 21, 2023 at 11:26am

Meiosis, the cell division process giving rise to sperm and eggs, involves several steps, one of which is the formation of a large protein structure called the synaptonemal complex. Like a bridge, the complex holds chromosome pairs in place enabling necessary genetic exchanges to occur that are essential for the chromosomes to then correctly separate into sperm and eggs.

A significant contributor to infertility is defects in meiosis.  what happens right before that when the synaptonemal complex forms between the daughter reproductive cells .

Previous studies have examined many proteins comprising the synaptonemal complex, how they interact with each other, and have identified various mutations linked to male infertility. The protein the researchers investigated in this study forms the lattices of the proverbial bridge, which has a section found in humans, mice, and most other vertebrates suggesting it is critical for assembly. Modeling different mutations in a potentially crucial region in the human protein enabled the team to predict which of these might disrupt protein function.

The authors used a precise gene editing technique to make mutations in one key synaptonemal complex protein in mice, which allowed the researchers, for the first time, to test the function of key regions of the protein in live animals. Just a single mutation, predicted from the modeling experiments, was verified as the culprit of infertility in mice.

Katherine Billmyre et al, SYCP1 head-to-head assembly is required for chromosome synapsis in mouse meiosis, Science Advances (2023). DOI: 10.1126/sciadv.adi1562. www.science.org/doi/10.1126/sciadv.adi1562

Part 2

Comment by Dr. Krishna Kumari Challa on October 21, 2023 at 11:21am

Why do some men not produce sperm? Scientists uncover one underlying reason for male infertility

Millions of couples worldwide experience infertility with half of the cases originating in men. For 10% of infertile males, little or no sperm are produced. Now, new research is shedding light on what may be going wrong in the process of sperm formation, leading to potential theories on possible treatments.

In most sexually-reproducing species, including humans, a critical protein structure resembling a lattice-like bridge needs to be built properly to produce sperm and egg cells. The team  discovered that in mice, changing a single and very specific point in this bridge caused it to collapse, leading to infertility and thus providing insight into human infertility in males due to similar problems with meiosis.

Part 1

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