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Wake-Up Call: Global Warming and Deforestation Threaten Wildlife

Research

May 21st, 2024
Wake-Up Call: Global Warming and Deforestation Threaten Wildlife

A New TAU Study Shows that Global Warming and Deforestation Could Cause Mass Animal Extinctions.

  • Life Sciences

A joint study by TAU and the University of Colorado (CU) states that the combination of global warming and extreme heat events, alongside the continued expansion of deforestation in the world, may be devastating for many species of animals, especially those that know how to climb trees. As part of the study, the researchers focused on lizards and showed that following the effects of climate change, they will seek refuge from the hot ground by spending a lot of time on trees. However, due to human-related activities, such as deforestation, urbanization and the expansion of agricultural lands at the expense of natural lands, the availability of trees in the areas where the lizards live will decrease, and this may lead to the collapse of many populations.

 

The research was conducted under the leadership of doctoral student Omer Zlotnick from the laboratory of Dr. Ofir Levy at the School of Zoology, the Wise Faculty of Life Sciences and the Steinhardt Museum of Natural History at TAU and in collaboration with Dr. Keith Musselman from CU. The study was published in the journal Nature Climate Change. 

 

Climate Crisis: Animals Seeking Comfort in Trees

The researchers explain that the climate crisis and global warming force animals to search for more comfortable places to stay to escape the extreme heat, just as we look for a shady area on a hot day. For climbing animals, trees can serve as a comfortable and pleasant refuge. One of the reasons for this is that the farther you get from the ground, the lower the air temperature gets, and the stronger the wind becomes. Therefore, on hot days, for example, animals can climb up trees to escape from the hot ground.

 

 

The importance of trees, then, is expected to increase as the climate warms. The problem is that in many places in the world, the density of trees is decreasing, mainly due to phenomena such as deforestation and the expansion of the use of trees for various purposes such as construction, etc. This phenomenon creates a situation where, on the one hand, due to climate change, animals will depend more on trees for their survival, while on the other hand, the destruction of habitats will lead to a decrease in the availability of trees.

 

Lizards' Habitat Loss

Doctoral student Omer Zlotnik: "As part of the research, we wanted to examine how the combined effect of these two processes would be on animals. Specifically, we focused on lizards because they are very dependent on their environment to maintain a normal body temperature, and a lack of comfortable places to stay can affect them dramatically. In the study, we used a computer simulation to simulate where the lizard should be, in the sun, in the shade, or on the tree, every minute for 20 years, under the climate conditions that existed in the past and under those expected in the future. Using the simulation, we examined how populations of lizards would be affected by climate change when trees are available and how their situation would change following the felling of trees in their habitat".

 

Left to right - Dr. Ofir Levy & Omer Zlotnick

 

The results showed that, in general terms, climate change is going to benefit many lizard populations. In most places, the expected warming will allow lizards to be active longer throughout the day and the year, as there will be fewer times when it is too cold to come out of their burrows. However, when climate change occurs at the same time as the felling of trees, the trend is likely to reverse, so that many lizard populations may collapse. In areas with a warm climate, climate change, even if no trees are cut down, is expected to harm lizard populations, and cutting down trees will make the situation even worse.

 

"What's really interesting about lizards is that they just need to be able to move a short distance around the tree trunk to get to a very different climate and habitat environment", said Keith Musselman, an assistant professor in the Department of Geography and CU Boulder’s Institute of Arctic and Alpine Research. 

 

Musselman: "These microhabitats are particularly important when we think about how we modify our natural environment and make conservation decisions".

 

Dr. Ofir Levy concludes: “Our research focused on lizards, but it actually demonstrates a broader problem that is relevant to many species of animals. Our results demonstrate that trees are crucially important to the ability of animals to cope with climate change, and in many cases, their availability can be, for the animals, the difference between crawling and collapsing. Our research proves how important it is to preserve forested areas and trees in general, especially in light of the changing climate. As part of the research, we also provide more practical tools for decision-makers, such as the height or density of trees required in different areas. We hope that this research will be used to build more effective programs for the conservation and restoration of natural areas so that we can provide the animals with what they need to survive".

 

Research

May 19th, 2024
Will Existing Drugs Stop Cancer's Bone Spread?

Existing Meds May Prevent Bone Spread in Breast Cancer Patients

  • Medicine

Researchers at TAU developed a new therapeutic strategy based on existing medications to inhibit bone metastasis in breast cancer patients. Using both an animal model and tissue samples from patients in Israel and the US, they demonstrated that a combination of drugs already available on the market can hinder bone metastasis and improve survival. Based on their findings, the researchers predict that in the future, the treatment can apply to human patients with breast cancer, as well as other types of cancer.

 

The groundbreaking study was led by Prof. Neta Erez and Dr. Lea Monteran at Prof. Erez's Laboratory for Tumor Biology at the Pathology Department, Faculty of Medical and Health Sciences, Tel Aviv University. The paper was published in Cancer Discovery. The researchers explain that over 75% of patients with metastatic breast cancer suffer from bone metastases, which destroy bone tissues, causing fractures and a great deal of pain. Moreover, with today's technologies such as MRI or CT imaging, diagnosis of bone metastasis occurs, in most cases, when the disease cannot be cured.  In this study, the researchers looked for a novel way to inhibit the progression of bone metastasis. 

 

Cancer Cell Sabotage

Prof. Erez: "A tumor is more than a collection of cancer cells. Just like healthy tissues, a tumor is a whole ecosystem consisting of reciprocal interactions between different cell types, including cells of the immune system, connective tissues, blood vessels, etc. Moreover, cancer cells often 'corrupt' normal cells, causing them to 'collaborate' with the tumor and support the growth of cancer cells. Blocking the communication channels between cancer cells and healthy cells at an early stage can hinder the growth of cancer cells in the bones. To achieve this, the early stages of the process must be investigated". To understand processes of bone metastasis the researchers compared three types of bones from model mice:  healthy, early-stage metastasis, and advanced metastasis. They found that when bone metastasis begins, T cells from the immune system arrive on the scene and penetrate the metastases but are unable to destroy them. 

 

Prof. Neta Erez

 

Next, the researchers discovered that the killing activity of T cells is inhibited by another type of immune cells and identified the proteins responsible for this effect. To neutralize these inhibitory proteins and reactivate the T-cells, they created a novel therapeutic combination that has never been tried before a drug that counters the activity of the immune-inhibiting cells, along with an antibody that activates T cells. This combination was administered to model mice, and the results were encouraging: the bone metastases were reduced, and survival was significantly improved compared to untreated model mice. 

 

At the final stage of the study, the TAU research team collaborated with the Sheba and Ichilov (Tel Aviv) Medical Centers and the Baylor College of Medicine in Texas. They examined tissue samples from bone metastases taken from patients with breast cancer, as well as other types of cancer, and found that the immune cells inhibiting T cells express the same proteins as those found in the animal model. Prof. Erez: "Our findings suggest that the combined treatment – attacking the cells that inhibit T cells while activating the T cells – can be effective for treating bone metastasis resulting from breast cancer as well as other types of cancer. The great advantage of our strategy is that both drugs are already available on the market and consequently, the process of obtaining permits to use them against bone metastasis in humans can be relatively short. At the same time, clinical trials need to verify the effectiveness of the new therapeutic strategy".

 

The study was funded by the Israel Cancer Research Fund (ICRF), the Israel Science Foundation (ISF), Worldwide Cancer Research (WWCR), and the U.S. Department of Defense (DoD).

 

Research

May 16th, 2024
How Do Lightning Storms Affect North Pole Sea Ice?

TAU Research Shows that Lightning Storms are Causing Sea Ice to Melt Faster at the North Pole

  • Environment

A new international study with the participation of researchers from Tel Aviv University found that alongside the general warming of the globe, lightning storms have been directly hastening the ongoing process of sea ice retreat covering the Arctic Ocean. According to the researchers: “Until recently, lightning as a phenomenon was extremely rare in the Arctic region of the North Pole, due to the intense cold. However, due to the warming of the Earth, lightning storms have become more common there in the summers, and these storms further increase the melting process of the ice sheets - in a feedback loop”.

 

Prof. Colin Price and MSc student Tair Plotnik from the Department of Geophysics at TAU’s Porter School of the Environment and Earth Sciences participated in the study, alongside Dr. Anirban Guha and Dr. Joydeb Saha from Tripura University in India. The article was published in the journal Atmospheric Research.

 

Arctic's Cold Reality: Understanding Rapid Ice Loss

Prof. Price explains: “The Arctic region is defined as the region located north of the 66.5° latitude. In the heart of this region, around the North Pole, there is no land, and due to the extreme cold conditions, the sea is covered with a thick layer of sea ice, which currently extends over about 8 million square kilometers. The white ice reflects the sun’s rays and thus contributes to the cooling of the Earth. But in recent decades, with the warming of the Earth, the ice cover has retreated at a rate of about 70,000 square kilometers per year, or 6.5% per decade (In this context, it is important to note that the temperature at the North Pole has been rising at an accelerating pace - about 4° until today, in contrast to about 1° on Earth as a whole).

 

Prof. Colin Price

 

The retreat of the ice increases the warming even further, because the dark areas of the ocean under the ice, which are getting bigger and bigger, absorb the sun’s rays that would normally be reflected in space. This is how a feedback loop is created: the retreat of the ice increases the warming, which in turn increases the melting of the ice, and the cycle repeats”.

 

Lightning's Role in Polar Ice Melt

According to the researchers, the phenomenon of melting ice sheets at both poles is firstly attributed to the result of human activity due to the increase in the amount of greenhouse gases in the atmosphere, creating a kind of ‘blanket’ that preserves the heat and does not allow it to disperse into space. However, studies have not found a direct match between the greenhouse gas changes, which increase at a more or less constant rate every year, and the rate of sea ice melting, which varies immensely from year to year. This study sought to examine the possible effect of another factor – lightning storms - on the melting of the sea ice in the Arctic region.

 

The researchers explain that lightning, as a phenomenon, was extremely rare in the Arctic region until recently, due to the intense cold that prevails there. But in recent decades, apparently, due to global warming, lightning storms have been observed there in the summertime, when the sun does not set at all, heating the surface (Lightning storms form when the surface of the ground heats up, and pockets of air rise in the atmosphere, where they cool, condense, and become clouds that sometimes develop into thunderstorms).

 

 

To test their hypothesis that lightning storms contribute to the melting of the ice around the North Pole, the researchers compared two sets of data: images from NASA satellites that have been documenting the retreat of the ice in the Arctic Sea for more than 40 years, and lightning data collected by the global network WWLLN (wwlln.net) – which includes around 70 lightning detection stations, deployed in research institutions all over the world – one of which stands on the roof of the Faculty of Exact Sciences building at TAU. Prof. Price explains: “Lightning is the result of a massive electric field that is discharged at once and transmits radio waves that can be received even thousands of kilometers away from the lightning. The global network’s sensors detect and map thunderstorms anywhere on the planet, in real-time and non-stop. Cross-referencing the information from the various stations allows for an accurate determination of the location and time of each lightning strike detected, and thus, a global map of lightning over time is obtained. For this study, we collected data on lightning in the Arctic region during the summer months of June, July and August every year since 2010".

 

Lightning Storms: Catalysts for Polar Ice Melt

A statistical analysis of the ice sheet retreat crossed with the number of lightning storms revealed a correlation: as the number of storms increased in a certain year, so did the melting of the sea ice increase that year. The researchers explain this by comparing thunderstorms to a giant vacuum cleaner, sucking water vapor up from the surface layer to the upper atmosphere (5-10km altitude), where it accumulates and acts like an additional blanket, trapping the surface heat from leaving, and increasing the surface temperature – just like man-made greenhouse gases. Another possibility observed in a previous study is that these same lightning storms lead to an increase in the formation of high cirrus clouds in the upper layers of the atmosphere – which also form a similar 'blanket'.

 

Prof. Price concludes: “In our research, we found a clear statistical relationship between the number of lightning storms in the Arctic region in a certain year and the rate of sea ice melting that year. This means that the storms are another factor that increases the melting of the polar ice, producing a feedback loop: the initial melting of the ice increases the dark surface areas of the sea, which absorb more of the sun’s rays, warming up the waters, causing more melting, accelerating the rate of warming, which in turn increases the number of lightning storms, and the cycle repeats itself. As a result of this, and of the warming of the Earth in general, we expect that the frequency of lightning storms in the Arctic region will increase in the coming years, and with it, the rate of sea ice retreat in the Arctic Sea will accelerate".

Is the Heaviest Black Hole in Our Galaxy Closer Than We Think?

Research

Apr 16th, 2024
Is the Heaviest Black Hole in Our Galaxy Closer Than We Think?

Gaia Spacecraft Reveals Massive Black Hole in Milky Way

  • Astronomy

An international team of researchers, with the participation of researchers from Tel Aviv University (TAU) led by Prof. Tsevi Mazeh, discovered a star which orbits a black hole 33 times heavier than the sun’s mass, and lies 1500 light-years away from Earth. The black hole, discovered using data from the European Gaia spacecraft, is more than three times heavier than the other known black holes in our galaxy. 

 

The Gaia spacecraft was launched by the European Space Agency in 2013 and has since then been regularly measuring the position and brightness of over a billion stars in our galaxy – the Milky Way galaxy – with unprecedented precision, equivalent to accurately determining the position of a single grain of sand on the moon to the millimeter. 

 

An organization of hundreds of scientists across Europe processes the data coming in from the spacecraft and makes it accessible to the entire scientific community. The research group was led by Prof. (emeritus) Tsevi Mazeh, from TAU’s Raymond and Beverly Sackler School of Physics and Astronomy, recently awarded the Israel Prize in Physics for the year 2024. Prof. Mazeh participates in the study of binary star systems discovered using spacecraft data. The research was published in the prestigious journal Astronomy & Astrophysics.

 

Credit: ESA/Gaia/DPAC

 

Cosmic Odyssey: Exploring the Depths of the Universe

The large sample of binary stars should also include systems which include a black hole - one of the rarest celestial objects in the universe. The existence of a black hole is one of the most amazing phenomena in the universe, the existence of which was predicted by Einstein’s theory of general relativity back in 1939.

 

According to the accepted theory, when the fuel for the nuclear combustion process that takes place in the core of a star runs out, it collapses in on itself, towards its center. If the star is massive enough, all the remaining matter collapses into a single point of infinite density. It is possible, therefore, to see the black hole as the “corpse” of a star that has ended its life cycle and collapsed in on itself. Astrophysicists are still trying to understand the extreme conditions that lead to the collapse of matter into the central point, and therefore every discovery of a black hole is accompanied by enormous excitement among astronomers.

 

Into the Abyss of the Black Hole

It is very difficult to discover black holes since light cannot overcome the strong gravitational force in its vicinity. When a black hole is in a binary system with a normal star, the motion of the visible star is used to measure the mass of its invisible partner and thus prove that it is indeed a black hole. Indeed, in a matter of just a few years, the Gaia spacecraft has already discovered two black holes.

 

With the expectation that the data that continues to be collected by the spacecraft will lead to the discovery of more black holes, Prof. Mazeh together with Prof. Laurent Eyer from the University of Geneva established a small team to find black holes using the spacecraft’s data, including scientists from France, Germany, Spain, Belgium, Poland and Switzerland. While examining the new data, the team came across a binary system containing a special black hole, the likes of which has never been found before, with a mass of 33 solar masses, around 1,500 light years away from us.

 

The new black hole is more than three times heavier than any other known black hole in the Milky Way galaxy. The binary system, named Gaia BH3, contains an ordinary star that seems to have formed more than ten billion years ago when our galaxy was still very young. The star orbits the black hole in an 11-year cycle.

 

Prof. Tsevi Mazeh - 2024 Israel Prize Winner in Physics

 

At the suggestion of Prof. Mazeh, it was decided to publish the sensational disclosure right now and not wait until the orderly publication of all the systems that were discovered. The entire spacecraft team, including researchers from TAU - Prof. Shay Zucker, head of the Porter School of Environment and Earth Sciences, Dr. Simchon Faigler, Dr. Sahar Shahaf (now at the Weizmann Institute), Dr. Dolev Bashi (now at the University of Cambridge), Avraham Binnenfeld (research student) and Oded Orenstein (second-year undergraduate student) - are listed as contributors to the scientific article published today which reports on the discovery.

 

Prof. Tsevi Mazeh: “This is an exciting discovery of the heaviest black hole in a binary system known today in the galaxy. About thirty years passed from the first hypothesis of the existence of a black hole until the discovery of the first black hole, and more than fifty years passed before we were able to discover Gaia BH3 - the binary system with the longest cycle known today. It is amazing how humankind manages to navigate the vast expanses of the universe and discover such mysterious objects. I am convinced that the discovery will lead to a new mode of thinking regarding the presence and prevalence of the black holes that cruise through the expanses of our galaxy.”

Research

Apr 14th, 2024
Heart Disease's Cancer Link Unveiled

A Recent TAU Study Exposes the Connection Between Heart Disease and Cancer

  • Medicine

Researchers at Tel Aviv University and the Leviev Cardiothoracic and Vascular Center at the Sheba Medical Center have found a mechanism that is responsible for increasing the risk of developing cancer among patients with heart disease: those small extracellular bubbles, or vesicles (sEVs), that are secreted from the sick heart to heal itself are released into the bloodstream – and promote the growth of cancer cells throughout the body. The researchers estimate that the important discovery may improve the protocols for treating heart disease so that clinicians also consider the increased risk of cancer. The study was funded by the Israel Cancer Association and the Israel Science Foundation. 

 

The research was conducted under the leadership of Prof. Jonathan Leor from the Neufeld Cardiac Research Institute, Faculty of Medical & Health Sciences at Tel Aviv University and the Taman Institute at Sheba’s Leviev Center and his student Tal Caller, a medical and research student at Tel Aviv University's School of Medicine. The research was published in the important medical journal Circulation.

 

Heart Disease's Silent Hand in Cancer's Rise

Caller explains: “In 2013, the Israeli cardiologist Tal Hasin showed for the first time that there is a connection between heart failure and cancer. Patients with heart disease are at a higher risk of developing cancer, and since heart disease is already a leading cause of death–first place in the US and second place in Israel – that means that many people are at risk. Our research revealed that the diseased heart secretes cancer-promoting factors, which we identified as small extracellular vesicles (sEVs). These are tiny particles wrapped in a simple membrane, which all cells secrete, However, due to heart damage, these vesicles are released in greater quantities and contain factors related to inflammation, healing, growth, creation of new blood vessels, and changes in the immune system. These vesicles move through the circulatory system and eventually reach the tumor or the pre-cancerous tissue”.

 

Caller adds, “Following an injury in the heart muscle and deterioration to heart failure, sEVs containing growth factors and small nucleic acid molecules that promote cell division are released. These sEVs contribute to the healing of the injured cardiac tissue. However, released from the injured heart, those vesicles move within the body’s circulatory system, eventually targeting cancerous growths”.

 

Prof. Jonathan Leor: “Many theories have been proposed to explain the increased risk of cancer in heart patients. They started with shared risk factors such as smoking, diabetes, and obesity and ended with a single protein or molecule. We showed for the first time that the diseased heart secretes sEVs that contain thousands of different growth factors. These bubbles directly promote the growth of certain tumors and also modulate the immune system, making the body more vulnerable to tumor growth”.

 

To test their hypothesis, the researchers at TAU inhibited the formation of sEVs in animal models with heart disease and found that the risk of cancer decreases along with the inhibition of vesicle production. However, this is not a viable therapeutic option since inhibiting the production of the vesicles causes severe undesired side effects.

 

Disrupting Cancer's Path

Prof. Leor: “When you systemically inhibit the formation of sEVs, you get less cancer – but you cause collateral damage along the way. That is why we tried a different strategy: treat the patient’s heart to reduce the damage to the cardiac tissue so that it secretes fewer sEVs. We used spironolactone, which is a well-known, old, and effective drug used to treat heart failure. We treated the animals with spironolactone at a very early stage of the disease and found that the heart secreted 30% fewer sEVs– and the cancerous tumors grew more slowly. Our experiment shows that it is possible to intervene in heart disease in a way that reduces the risk of cancer among heart patients”.

 

As for the clinical implications of the study, Caller is careful in his words: “It may be necessary to adjust the existing treatments for the heart so that they also consider the risk of cancer. In addition, it is possible to find biomarkers among heart patients that will indicate an increased risk of cancer since not all patients are at an increased risk. This is basic research, and much work is still required to unravel the connection between the two”.

 

Moshe Bar-Haim, CEO of the Israel Cancer Association, adds: “Thanks to public donations and designated funds, the research committee of the Israel Cancer Association examines and selects dozens of studies every year and funds researchers and doctors from research and treatment centers across Israel. From these studies, new methods were developed for the diagnosis, treatment, and rehabilitation of cancer patients. Research has no territorial boundaries, so every achievement in research here in Israel is an achievement for the entire world. We hope that the new research – that reveals that because of heart diseases, extracellular bubbles are secreted and increase the risk of cancer – will allow for immediate application in Israel and around the world for the benefit of accurate treatment for patients”.

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