The secret of centenarians, the oldest traces of life, pigs for xenotransplantation

The oldest traces of life found — they are 3.5 billion years old

When scientists determine the age of life on Earth, they largely rely on indirect data. Dating the material traces of the activity of ancient living organisms is extremely difficult: over billions of years, geological rocks are reformed. They are folded, melted, and recrystallized. Organic matter in this process turns into kerogen — a polymer of amino acids and carbohydrates. No organic substance can survive under such conditions. Therefore, ancient fossils or carbon compounds are dated by the surrounding rock layers. Moreover, traces of ancient organic matter may not be of biological origin at all; they could have formed geologically.

This is why the study published this week by an international group of scientists is so important. Geologists examined rock samples taken from India, in the oldest preserved region of the continental shield. The sedimentary rock, formed billions of years ago on the seabed of a former ocean, preserved traces of an ancient microbial mat (a colony of bacteria that formed in layers over a long period). The main task was to determine the age of this kerogen. By measuring the concentration of uranium and lead isotopes in zircon crystals that covered the microbial mat, the geologists determined that they formed 3.5 billion years ago.

Additional studies proved that the scientists were indeed dealing with kerogen of biological origin — this was shown by the ratio of carbon isotopes.

To date, this is the oldest proven material trace of life that has been relatively accurately dated.

Scientists at Sechenov University aim to create a genetic line of pigs suitable for organ transplantation into humans

In recent years, scientists have been actively exploring the possibilities of xenotransplantation — transplanting organs from animals to humans. Today, pigs are most often considered as donors — their hearts, livers, and kidneys are similar to ours in physiology and size. At the same time, pigs reproduce and grow quickly, allowing relatively short-term creation of genetic lines with desired characteristics. Modern genetic modification methods are also used for this.

Xenotransplantation has many problems. The main one is the immune response of the human body to the invasion of foreign biological material. So far, all experiments conducted on humans have resulted in organ rejection. Nine such xenotransplantations have been performed to date. But scientists are working to overcome this problem. Researchers use genome editing technologies — primarily CRISPR/Cas9. “Turning off” genes in pig material that are responsible for synthesizing specific substances that trigger an immune response could solve the problem. At the same time, human-like genes that regulate inflammation and blood clotting are introduced into the pig genome.

This week, scientists from the First Moscow State Medical University named after Sechenov published a large-scale study examining options for modifying the pig genome. In this work, the researchers stated a strategic goal — to breed a population of genetically modified pigs whose organs could be transplanted into humans. This work will take at least 10 years: restructuring the animal's immune system and adapting it for compatibility with the human body is a slow process.

Physicists against snoring

Humanity solves a wide variety of complex problems, but has not yet managed to conquer snoring. Oddly enough, doctors still do not fully understand how it is formed — and therefore do not fully understand what to do about it. Now physicists have joined the effort — it seems the problem is keeping the entire scientific community awake.

Researchers from the Royal Institute of Technology in Stockholm (Sweden) built a 3D model of the upper respiratory tract and studied how airflow forms during sleep, how soft tissues behave, and how the body produces annoying snoring sounds. The main focus of the Swedish physicists' effort was the soft palate. They found that the loudest snoring sounds occur when the airflow passes unstably and irregularly through the folds of the soft palate tissue.

Having established this fundamental point, the Swedes concluded that fighting snoring requires working with the vibrations of the soft palate and the unstable aerodynamic load on it. This means attention should be paid to procedures that strengthen the tissues of the nasopharynx.

However, the physicists did not specify how exactly to do this. They say that new research is needed first: to understand how the stiffness of the palate affects the amplitude, frequency, and even the pattern of airflow. In short, if you have a snoring relative at home, you have a real black box — a gift for acoustic physicists.

Perhaps the authors will eventually recommend treatment options. For now — let's keep snoring!

Lunar expeditions could contaminate the satellite's polar regions with terrestrial microorganisms

Until now, Earthly expeditions to the Moon have landed closer to the equator — where it is easiest to do so. But now that water has been proven to exist in craters near the lunar poles, human attention is focused on these areas. American astronauts plan to land precisely at the poles in upcoming missions. This entails not only technical problems.

The fact is that the human body contains more bacterial cells than human cells. This means that our spacecraft, spacesuits, and all our equipment are teeming with bacteria. It has been proven that terrestrial microorganisms can survive in space. They survive even the strictest sterilization, can withstand vacuum, cold, and zero pressure. On the lunar surface closer to the equator, bacteria are guaranteed to die from ultraviolet radiation and the +127°C temperatures that prevail on the sunlit side during the day. Even bacterial spores did not survive there, as proven by the Apollo landings. However, in the polar regions, according to the authors of a recent article, microorganisms could not only survive but also divide. After all, temperatures near the south and north poles of our satellite do not rise above the survival threshold of bacteria and fungi. Ultraviolet kills microorganisms within a day, but in craters where direct sunlight is blocked by the terrain, it may not reach them.

Microbes are unlikely to grow and reproduce under such conditions — there is no liquid water there, only ice. But they could certainly spoil the research picture. If astronauts bring terrestrial microbes on their spacesuits or instruments, then during a second outing in the same area, these microbes could easily be detected. This would create false assumptions about lunar life.

The secret of super-centenarians: the immune system restructures itself to defeat cancer and old age

Scientists from Osaka University have discovered how people over 110 manage to avoid deadly diseases. It turns out that their immunity not only “works” but restructures itself, creating an army of killer cells to destroy cancer at its root.

We are used to thinking that with age, the body's defenses inevitably weaken, leaving us vulnerable to infections and cancer. However, a study by Japanese scientists turns this notion on its head. It turns out that in those who have crossed the 110-year mark, the immune system does not decline but undergoes an amazing evolutionary restructuring, turning ordinary helper cells into deadly tumor hunters.

In the study, scientists compared the immune status of three groups: people aged 70–90, centenarians, and super-centenarians (over 110). The result was astonishing. In the blood of people over 110, a huge population of rare immune cells was found — CD4 cytotoxic T lymphocytes (CD4 CTLs).

While in ordinary elderly people their proportion was only about 4%, in centenarians this figure rose to 10%, and in super-centenarians it reached a staggering 18%. This means that almost every fifth immune cell in 110-year-olds turns into a precision weapon.

The main secret is that these cells are hybrids. Normally, T cells are divided into “helpers” (CD4), which coordinate the attack, and “killers” (CD8), which kill the enemy. But in super-centenarians, the “helpers” retrain: they take on the functions of killers, stocking up on enzymes (perforins and granzymes) that literally dissolve diseased or cancerous cells.

The most intriguing discovery awaited the researchers when they analyzed what exactly these cells target. By comparing the receptors of CD4 CTLs from super-centenarians with a database of cancer patient receptors, the scientists found a remarkable overlap.

About 30 sequences matched receptors found in patients with lung, breast, and liver cancer. However, critically, the super-centenarians themselves had never had cancer in their lives.

This led to a bold hypothesis: the bodies of long-lived individuals maintain constant “immune vigilance.” As soon as the first microscopic mutant cells appear in tissues, specialized CD4 CTLs instantly recognize and destroy them, preventing the tumor from even starting to develop. Essentially, these people carry a lifelong vaccine against age-related cancers.

Previously, it was thought that a large number of such cells in the elderly was merely a coincidence or a side effect of aging. The new study proves the opposite: it is a conscious adaptation. The cells actively clone themselves — replicating their exact copies — to counter the threats accumulating with age.

This discovery gives scientists a new goal: if we can understand how this restructuring is triggered, perhaps in the future we will be able to “switch on” such a protective mechanism in ordinary people, significantly increasing their healthy lifespan.