Comment

Comment by Dr. Krishna Kumari Challa on July 10, 2024 at 6:49am

Initially, the researchers investigated whether cell growth can be regulated with an externally administered substance. Once successful, they examined whether the cells functioned normally.

They used stem cells to create insulin-producing β-cells that they then transplanted into laboratory animals. The cells regulated the blood glucose levels of the animals throughout the almost six-month experiment.
The cells are also able to differentiate into other tissue types as usual, and the researchers have not observed any differences in them other than their inability to proliferate without their say-so.
Stem cells are very primitive cells, as they have to be able to divide in abundance and develop in many different directions. They have potential for a range of purposes, but their primitive nature also poses a problem: What if some cells are not differentiated, but continue to grow in a primitive form? According to the scientists of the study, the research group's solution enables the efficient proliferation of cells during production, which can be halted at the desired time, such as following transplantation.
The solution also makes it possible to edit cells without fear of adverse effects of the editing itself. For example, cells can be made into something that the recipient's immune system does not recognize.
Previously, such cells would have been highly risky, as the immune system also monitors the onset of cancer. Now, that risk is very small or non-existent. Ideally, these cells could be turned into products suited to everyone and, when necessary, quickly deployed.

Rocio Sartori-Maldonado et al, Thymidylate synthase disruption to limit cell proliferation in cell therapies, Molecular Therapy (2024). DOI: 10.1016/j.ymthe.2024.06.014

Comment by Dr. Krishna Kumari Challa on July 10, 2024 at 6:46am

Scientists create a cell that precludes malignant growth

Cell therapies could help in the treatment of hereditary diseases, myocardial infarction and hundreds of other diseases. For many blood diseases, new cells can already be transplanted into human patients, and diabetes has also been treated by transplanting cells obtained through organ donation or, more recently, β-cells modified from the patient's own stem cells.

A risk associated with gene-edited cells is unintentional DNA mutations, including those that predispose patients to cancer. Moreover, the difference in tissue types makes it impossible to transfer cells simply from one person to another.

Cells that suit anyone, or immunologically invisible cells, as it were, have been created, but they too are associated with an increased risk of cancer. Over a decade ago,  a research group set out to develop cells where these problems could be avoided. Now, the group has succeeded in producing cells which cannot proliferate unaided and which cannot therefore turn into malignant cells.

The study was published in Molecular Therapy.

Almost all of our diseases are fundamentally caused by cellular dysfunction. One medical dream is to fight tissue damage, diseases or even aging with new healthy cells. This new study takes us a step closer to safe and novel cell therapies.

The researchers modified stem cells to divide only if they are supplemented with thymidine, one of the building blocks of DNA. The cells that have been subjected to this safety treatment cannot replicate their genome without the supplementary component vital for DNA synthesis. This precludes their proliferation. When the cells are differentiated for their various tasks, they cease to divide and no longer require the supplement. The innovation has been protected by the University's Helsinki Innovation services (HIS).

Part 1

Comment by Dr. Krishna Kumari Challa on July 9, 2024 at 11:53am

Air pollution linked to a decrease in IVF birth rate success, new study shows

A pioneering study, presented at the ESHRE 40th Annual Meeting in Amsterdam, has revealed that exposure to fine particulate matter (PM) prior to the retrieval of oocytes (eggs) during in vitro fertilization (IVF) can reduce the odds of achieving a live birth by almost 40%.

The study analyzed PM10 exposure in the two weeks leading up to oocyte collection, finding that the odds of a live birth decreased by 38% (OR 0.62, 95% CI 0.43–0.89, p=0.010) when comparing the highest quartile of exposure (18.63 to 35.42 µg/m3) to the lowest quartile (7.08 to 12.92 µg/m3). The study abstract was published in Human Reproduction.

Conducted over an eight-year period in Perth, Australia, the research analyzed 3,659 frozen embryo transfers from 1,836 patients. The median female age was 34.5 years at the time of oocyte retrieval and 36.1 years at the time of frozen embryo transfer.

The study examined air pollutant concentrations over four exposure periods prior to oocyte retrieval (24 hours, two weeks, four weeks, and three months), with models created to account for co-exposures.

Increasing PM_2.5 exposure in the three months prior to oocyte retrieval was also associated with decreased odds of live birth, falling from 0.90 (95% CI 0.70–1.15) in the second quartile to 0.66 (95% CI 0.47–0.92) in the fourth quartile.

Importantly, the negative impact of air pollution was observed despite excellent overall air quality during the study period, with PM₁₀ and PM_2.5 levels exceeding WHO guidelines on just 0.4% and 4.5% of the study days, respectively.

 Leathersich S.J, et al, Particulate matter (PM2.5 and PM10) exposure prior to oocyte collection is associated with decreased live birth rates in subsequent frozen embryo transfers. Human Reproduction (2024).

Comment by Dr. Krishna Kumari Challa on July 9, 2024 at 11:21am

Boys born with higher natural resistance to HIV, study finds

Baby girls are more likely to acquire HIV from their mothers during pregnancy or childbirth than infant boys, who are conversely more likely to achieve cure or remission, researchers say in a new study that sheds light on the gender differences in immune systems.

An estimated 1.3 million women and girls living with HIV become pregnant each year and the rate of transmission to the child during pregnancy, labor, delivery or breastfeeding—in the absence of any intervention—ranges from 15 to 45%, according to the World Health Organization.

This new study identified some of the key mechanisms by which sustained HIV remission can be achieved—mechanisms that are relevant to children and adults alike.

Researchers  evaluated 284 infants in KwaZulu-Natal, South Africa, one of the world's highest HIV-prevalent areas, who were started at birth on a mix of HIV medicines known as combination anti-retroviral therapy (cART), after being exposed to HIV during pregnancy.

They found that HIV transmission to male fetuses was 50% less common than to females.

Affected males had lower levels of the virus in the blood and to date, in this study, four male infants have been identified who have achieved HIV cure/remission—i.e. maintained undetectable levels of HIV in the blood even without therapy.

HIV cure is categorized as "true cure" in which the virus has been eradicated totally from the body and "functional cure" or "cure/remission," in which the virus is no longer detectable in the blood even after treatment has been discontinued.

The researchers say the disparity found between male and female infants is likely due to the lower levels of activated CD4 T cells in male fetuses than in females, making it harder for the virus to establish a reservoir and providing a barrier against infection.

If by chance a virus gets transmitted to a male, it struggles to persist because there are not enough activated CD4 T cells available to sustain the infection.

CD4 T cells are a type of white blood cell that help the body fight infections such as HIV. They are an important part of the immune system and are targeted by HIV during infection. HIV spreads more slowly with lower CD4 T cell counts.

Nomonde Bengu et al, Sustained aviremia despite anti-retroviral therapy non-adherence in male children after in utero HIV transmission, Nature Medicine (2024). DOI: 10.1038/s41591-024-03105-4

Comment by Dr. Krishna Kumari Challa on July 9, 2024 at 11:13am

Researchers reveal a master controller of development and aging

Researchers have unlocked crucial molecular secrets of aging in cells, potentially paving the way to improve quality of life as people age.

The study, published in Cell Metabolism, decoded the process by which genes regulate how people mature as they grow and age.

By analyzing molecular datasets from both people and mice and then comparing different age groups over time, the researchers investigated the activity of genes involved in both developmental and aging processes.

Master controller genes regulate which genes are turned on or off in each of our cells, making sure that each cell does its specific job.

The scientists followed the activity of the master regulator Activator Protein 1 or AP-1 and found that it progressively activated adult genes, while the activity of 'early-life' genes involved in development were dialed down, and this process was shared across cell types.

The study found this process in our cells was predictable across the different life stages, as people mature.

It was ongoing in adulthood, likely because AP-1 is also activated by a number of stress and inflammatory processes as well as by a protein in our blood that increases with age. This further dampens genes most active early in life, which may drive many of the predictable changes of aging.

To address the diseases associated with aging, like Alzheimer's disease, metabolic liver disorders and stroke, researchers must first understand the process causing bodies to age.

By pinpointing AP-1 as a master controller linked to aging across cell types, scientists can now study the effects of drugs that reduce its activity to extend quality of life. The goal is to prevent diseases of aging from escalating or occurring in the first place by targeting the underlying aging process to allow people to grow older in better health.

 Ralph Patrick et al, The activity of early-life gene regulatory elements is hijacked in aging through pervasive AP-1-linked chromatin opening, Cell Metabolism (2024). DOI: 10.1016/j.cmet.2024.06.006

Comment by Dr. Krishna Kumari Challa on July 9, 2024 at 10:54am

Bacterial glitter: New findings open up possibilities for sustainable color technologies

An international team of researchers  has investigated the mechanism that makes some types of bacteria reflect light without using pigments. The researchers were interested in the genes responsible and discovered important ecological connections. Their findings appear in the Proceedings of the National Academy of Sciences.

The iridescent colors known from peacock feathers or butterfly wings are created by tiny structures that reflect light in a special way. Some bacterial colonies form similar glittering structures.

The scientists sequenced the DNA of 87 structurally colored bacteria and 30 colorless strains and identified genes that are responsible for these fascinating colonies. These findings could lead to the development of environmentally-friendly dyes and materials.

Scientists  discovered that the genes responsible for structural color are mainly found in oceans, freshwater, and special habitats such as intertidal zones and deep-sea areas. In contrast, microbes in host-associated habitats such as the human microbiome displayed very limited structural colour. 

The study results indicate that the colorful bacterial colony structures are not only used to reflect light. Surprisingly, these genes are also found in bacteria that live in deep oceans without sunlight. This could imply that the colors could reflect deeper processes of cell organization with important functions, such as protecting the bacteria from viruses, or efficiently colonizing floating food particles. These findings could inspire new, sustainable technologies based on these natural structures.

Colin J. Ingham et al, Structural color in the bacterial domain: The ecogenomics of a 2-dimensional optical phenotype, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2309757121

Comment by Dr. Krishna Kumari Challa on July 8, 2024 at 10:31am

Incredible New Tech Lets Scientists Watch Fetuses Develop in Real Time

Comment by Dr. Krishna Kumari Challa on July 8, 2024 at 9:45am

Species went extinct on all continents except Antarctica and in all types of ecosystems, from tropical forests and savannas to Mediterranean and temperate forests and steppes to arctic ecosystems.
Many of the extinct species could thrive in various types of environments. Therefore, their extinction cannot be explained by climate changes causing the disappearance of a specific ecosystem type, such as the mammoth steppe—which also housed only a few megafauna species.
Most of the species existed under temperate to tropical conditions and should actually have benefited from the warming at the end of the last ice age.
The researchers point out that the loss of megafauna has had profound ecological consequences. Large animals play a central role in ecosystems by influencing vegetation structure (e.g., the balance between dense forests and open areas), seed dispersal, and nutrient cycling. Their disappearance has resulted in significant changes in ecosystem structures and functions.

Jens-Christian Svenning et al, The late-Quaternary megafauna extinctions: Patterns, causes, ecological consequences and implications for ecosystem management in the Anthropocene, Cambridge Prisms: Extinction (2024). DOI: 10.1017/ext.2024.4

The numbers of extinct and surviving species come from the freely accessible database PHYLACINE 1.2.1, which lists all known mammals that have lived in the past 129,000 years, including those that have gone extinct recently or are only found in captivity.

Part 3

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Comment by Dr. Krishna Kumari Challa on July 8, 2024 at 9:43am

The dramatic climate changes during the last interglacial and glacial periods (known as the late Pleistocene, from 130,000 to 11,000 years ago) certainly affected populations and distributions of both large and small animals and plants worldwide. However, significant extinctions were observed only among the large animals, particularly the largest ones.

An important observation is that the previous, equally dramatic ice ages and interglacials over the past couple of million years did not cause a selective loss of megafauna. Especially at the beginning of the glacial periods, the new cold and dry conditions caused large-scale extinctions in some regions, such as trees in Europe. However, there were no selective extinctions of large animals.

The large and very selective loss of megafauna over the last 50,000 years is unique over the past 66 million years. Previous periods of climate change did not lead to large, selective extinctions, which argues against a major role for climate in the megafauna extinctions.
Another significant pattern that argues against a role for climate is that the recent megafauna extinctions hit just as hard in climatically stable areas as in unstable areas.
Archaeologists have found traps designed for very large animals, and isotope analyses of ancient human bones and protein residues from spear points show that they hunted and ate the largest mammals.
Early modern humans were effective hunters of even the largest animal species and clearly had the ability to reduce the populations of large animals. These large animals were and are particularly vulnerable to overexploitation because they have long gestation periods, produce very few offspring at a time, and take many years to reach sexual maturity.
The analysis shows that human hunting of large animals such as mammoths, mastodons, and giant sloths was widespread and consistent across the world.

It also shows that the species went extinct at very different times and at different rates around the world. In some local areas, it happened quite quickly, while in other places it took over 10,000 years. But everywhere, it occurred after modern humans arrived, or in Africa's case, after cultural advancements among humans.
Part 2

Comment by Dr. Krishna Kumari Challa on July 8, 2024 at 9:41am

The evidence is mounting: Humans were responsible for the extinction of large mammals

The debate has raged for decades: Was it humans or climate change that led to the extinction of many species of large mammals, birds, and reptiles that have disappeared from Earth over the past 50,000 years?

By "large," we mean animals that weighed at least 45 kilograms—known as megafauna. At least 161 species of mammals were driven to extinction during this period. This number is based on the remains found so far.

The largest of them were hit the hardest—land-dwelling herbivores weighing over a ton, the megaherbivores. Fifty thousand years ago, there were 57 species of megaherbivores. Today, only 11 remain. These remaining 11 species have also seen drastic declines in their populations, but not to the point of complete extinction.

A research group  now concludes that many of these vanished species were hunted to extinction by humans.

They present this conclusion in a review article invited by and published in the journal Cambridge Prisms: Extinction. A review article synthesizes and analyses existing research within a particular field.

The researchers incorporated several research fields, including studies directly related to the extinction of large animals, such as:

• The timing of species extinctions
• The animals' dietary preferences
• Climate and habitat requirements
• Genetic estimates of past population sizes
• Evidence of human hunting

Additionally, they included a wide range of studies from other fields necessary to understand the phenomenon, such as:

• Climate history over the past 1–3 million years
• Vegetation history over the past 1–3 million years
• Evolution and dynamics of fauna over the past 66 million years
• Archaeological data on human expansion and lifestyle, including dietary preferences

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