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Tag: Life Sciences

Go Fish: Decline in Poleward-Moving Fish

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How Does Global Warming Impact Fish Abundance?

An extensive international study led by researchers from Tel Aviv University found a decline in the abundance of marine fish species that rapidly move toward the poles to escape rising sea temperatures. The researchers explain that many animal species are currently moving toward cooler regions as a result of global warming, but the velocity of such range shifts varies immensely for different species. Examining thousands of populations from almost 150 fish species, the researchers show that contrary to the prevailing view, rapid range shifts coincide with widescale population declines. According to the study, on average, a poleward shift of 17km per year may result in a decline of 50% in the abundance of populations. The international study was led by Ph.D. student Shahar Chaikin and Prof. Jonathan Belmaker from the School of Zoology in the Wise Faculty of Life Sciences and the Steinhardt Museum of Natural History at Tel Aviv University. The paper was published in the leading scientific journal Nature Ecology & Evolution. For the first time, the new study correlated two global databases: (1) a database that tracks fish population size over time, and (2) a database that compiles range shift velocities among marine fishes. Altogether, 2,572 fish populations belonging to 146 species were studied, mostly from the Atlantic and Pacific Oceans in the Northern Hemisphere.   Left to right - Prof. Jonathan Belmaker Shahar Chaikin Left to right – Prof. Jonathan Belmaker and Shahar Chaikin

Off the Hook

Prof. Belmaker explains: “We know that climate change causes animal species to move – northward, southward, upwards, or downwards – according to their location relative to cooler regions. In the mountains they climb upwards, in the oceans they dive deeper, in the Southern Hemisphere they move south toward Antarctica, and in the Northern Hemisphere, they move north toward the North Pole. In the present study we wanted to see what happens to species that move from one place to another: do they benefit by increased survivability, or are they in fact harmed by the shift – which was initially caused by greater vulnerability to climate change? We found that the faster fish shift toward the poles, the faster their abundance declines. Apparently, it is difficult for these populations to adapt to their new surroundings”.
PhD student Chaikin: “We found that species shifting their geographical range more rapidly towards the poles, are in fact more likely to lose their abundance (e.g. European seabass). Additional findings show differences between populations that are closer to or further from the poles – within the geographical range of a particular species. While it might have been assumed that populations closer to the cooler polar margins of the species range would be less affected by climate change, we found that the opposite is true: fast poleward range shifts of populations from higher latitudes resulted in a more rapid decline in abundance compared to equatorial populations of the same species”.
The researchers highlight that the new findings can and should guide environmental decisionmakers, by enabling a reevaluation of the conservation status of various species and populations. The study’s results suggest that populations exhibiting rapid poleward range shifts require close monitoring and careful management. Thus, for example, pressures that threaten their survival can be mitigated through measures like fishing limits. Prof. Belmaker: “The common belief is that rapid range shifts safeguard a species against local population decline. But in this study, we found that the opposite is true. Apparently, species rapidly shifting their range in search of cooler temperatures do so because they are more vulnerable to climate change, and consequently require special attention. Last year we published another study that focused on local fish species along Israel’s coastline, which resulted in similar findings: species that move towards deeper and cooler habitats in the face of rising water temperatures exhibit declining populations. In the next stage of our research, we intend to investigate this causal relationship in additional marine species, other than fish”.  

Do Viruses Have Consciousness?

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Bacteria-Targeting Viruses Adapt, Improving their Decision-Making.

Researchers from the Shmunis School of Biomedicine and Cancer Research at Tel Aviv University have deciphered a novel complex decision-making process that helps viruses choose to turn nasty or stay friendly to their bacterial host. In a new paper, they describe how viruses co-opt a bacterial immune system, intended to combat viruses like themselves, in this decision-making process. The study was led by Polina Guler, a PhD student in Prof. Avigdor Eldar’s lab, in addition to other lab members, at the Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences. The paper was published in Nature Microbiology.  

All-You-Can-Eat Bacteriophage

  Bacteriophages, also known as phages, are types of viruses that infect bacteria and use the infected bacteria to replicate and spread. Even though the word ‘bacteriophage,’ meaning ‘bacteria devouring’ in ancient Greek, suggests destruction, many phages can adopt a “sleeping” mode, in which the virus incorporates itself into the bacterial genome. In fact, in this mode of action, the virus can even have a symbiotic relationship with the bacteria, and its genes can help its host prosper.     In general, Eldar explains that phages usually prefer to stay in the “sleeping”, dormant mode, in which the bacteria “cares” for their needs and helps them safely replicate. Previous research published by the Eldar lab has shown that the phages’ decision-making uses two kinds of information to decide whether to stay dormant or turn violent: the “health status” of their host and signals from outside indicating the presence of other phages around.    
“A phage can’t infect a cell already occupied by another phage. If the phage identifies that its host is compromised but also receives signals indicating the presence of other phages in the area, it opts to remain with its current host, hoping for recovery. If there is no outside signal, the phage ‘understands’ that there might be room for it in another host nearby and it’ll turn violent, replicate quickly, kill the host, and move on to the next target”, Eldar explains.
 

Death by Phage

  The new study deciphers the mechanism that enables the virus to make these decisions. “We discovered that in this process the phage actually uses a system that the bacteria developed to kill phages”, says Guler. If it does not sense a signal from other phages—indicating that it has a good chance of finding new hosts—the phage activates a mechanism that disables the defense system. “The phage switches to its violent mode, and with the defense system neutralized, it is able to replicate and kill its host”, describes Guler. “If the phage senses high concentrations of the signal, instead of disabling the defense system, it utilizes its defense activity in order to turn on its dormant mode”.     “The research revealed a new level of sophistication in this arms race between bacteria and viruses,” adds Eldar. Most bacterial defense systems against phages were studied in the context of viruses that are always violent. Far less is known about the mechanisms of attacks and interaction with viruses that have a dormant mode. “The bacteria also have an interest in keeping the virus in the dormant mode, first and foremost to prevent their own death, and also because the genes of the dormant phage might even contribute to bacterial functions,” says Eldar.     “This finding is important for several reasons. One reason is that some bacteria, such as those causing the cholera disease in humans, become more violent if they carry dormant phages inside them – the main toxins that harm us are actually encoded by the phage genome,” explains Eldar. “Another reason is that phages can potentially serve as replacements to antibiotics against pathogenic bacteria. Finally, phage research may lead to better understanding of viruses in general and many human-infecting viruses can also alternate between dormant and violent modes”.

Unlocking Quantum Mysteries with Pendula

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Pendulum Experiment Sheds Light on Quantum Mysteries in Topological Materials, Revealing Insights Unreachable by Traditional Methods.

A recent study conducted at Tel Aviv University has devised a large mechanical system that operates under dynamical rules akin to those found in quantum systems. The dynamics of quantum systems, composed of microscopic particles like atoms or electrons, are notoriously difficult, if not impossible, to observe directly. However, this new system allows researchers to visualize phenomena occurring in specialized “topological” materials through the movement of a system of coupled pendula.   The research is a collaboration between Dr. Izhar Neder of the Soreq Nuclear Research Center, Chaviva Sirote-Katz of the Department of Biomedical Engineering, Dr. Meital Geva and Prof. Yair Shokef of the School of Mechanical Engineering, and Prof. Yoav Lahini and Prof. Roni Ilan of the School of Physics and Astronomy at Tel Aviv University and was recently published in the Proceedings of the National Academy of Sciences of the USA (PNAS).  
    Exploring Quantum Wave Phenomena   Quantum mechanics governs the microscopic world of electrons, atoms and molecules. An electron, which is a particle that moves in an atom or in a solid, may have properties that give rise to wave-like phenomena. For instance, it may demonstrate a probability of dispersing in space similar to waves spreading out in a pool after a stone is thrown in, or the capability to exist simultaneously in more than one place.     Such wave-like properties lead to a unique phenomenon that appears in some solid isolators, where even though there is no electric current through them, and the electrons do not move due to an external electric voltage, the internal arrangement of the material shows up in a state referred to as “topological”. This means that the wave of electrons possesses a quantity that can “close on itself” in different ways, somewhat like the difference between a cylinder and a Möbius strip. This “topological” state of the electrons, for which the 2016 Nobel Prize in Physics was awarded, is considered a new state of matter and attracts much current research.   Chaviva Sirote-Katz   Despite the theoretical interest, there is a limitation in measuring these phenomena in quantum systems. Due to the nature of quantum mechanics, one cannot directly measure the electron’s wave function and its dynamical evolution. Instead, researchers indirectly measure the wave-like and topological properties of electrons in materials, for instance by measuring the electrical conductivity at the edges of solids.     In the current study, the researchers considered the possibility of constructing a sufficiently large mechanical system that would adhere to dynamical rules akin to those found in quantum systems, and in which they could directly measure everything. To this end, they built an array of 50 pendula, with string lengths that slightly varied from one pendulum to the other. The strings of each neighboring pair of pendula were connected at a controlled height, such that each one’s motion would affect its neighbors’ motion.     Quantum Pendulum Insights   On one hand, the system obeyed Newton’s laws of motion, which govern the physics of our everyday lives, but the precise lengths of the pendula and the connections between them created a magical phenomenon: Newton’s laws caused the wave of the pendulum’s motion to approximately obey Schrödinger’s equation – the fundamental equation of quantum mechanics, which governs the motion of electrons in atoms and in solids. Therefore, the motion of the pendula, which is visible in the macroscopic world, reproduced the behaviors of electrons in periodic systems such as crystals.     The researchers pushed a few pendula and then released them. This generated a wave that propagated freely along the chain of pendula, and the researchers could directly measure the evolution of this wave – an impossible mission for the motion of electrons. This enabled the direct measurement of three phenomena. The first phenomenon, known as Bloch oscillations, occurs when electrons within a crystal are influenced by an electric voltage, pulling them in a specific direction. In contrast to what one would expect, the electrons do not simply move along the direction of the field, but they oscillate back and forth due to the periodic structure of the crystal. This phenomenon is predicted to appear in ultra-clean solids, which are very hard to find in nature. In the pendula system, the wave periodically moved back and forth, exactly according to Bloch’s prediction.     The second phenomenon that was directly measured in the pendula system is called Zener tunneling. Tunneling is a unique quantum phenomenon, which allows particles to pass through barriers, in contrast to classical intuition. For Zener tunneling, this appears as the splitting of a wave, the two parts of which then move in opposite directions. One part of the wave returns as in Bloch oscillations, while the other part “tunnels” through a forbidden state and proceeds in its propagation. This splitting, and specifically its connection to the motion of the wave in either direction, is a clear characteristic of the Schrödinger equation.     In fact, such a phenomenon is what disturbed Schrödinger, and is the main reason for the suggestion of his famous paradox; according to Schrödinger’s equation, the wave of an entire cat can split between a live-cat state and a dead-cat state. The researchers analyzed the pendula motion and extracted the parameters of the dynamics, for instance, the ratio between the amplitudes of the two parts of the split wave, which is equivalent to the quantum Zener tunneling probability. The experimental results showed fantastic agreement with the predictions of Schrödinger’s equation.     The pendula system is governed by classical physics. Therefore, it cannot mimic the full richness of quantum systems. For instance, in quantum systems, the measurement can influence the system’s behavior (and cause Schrödinger’s cat to eventually be dead or alive when it is viewed). In the classical system of macroscopic pendulum, there is no counterpart to this phenomenon. However, even with these limitations, the pendula array allows the observation of interesting and non-trivial properties of quantum systems, which may not be directly measured in the latter.     The third phenomenon that was directly observed in the pendula experiment was the wave evolution in a topological medium. Here, the researchers found a way to directly measure the topological characteristic from the wave dynamics in the system – a task that is almost impossible in quantum materials. To this end, the pendula array was tuned twice, so that they would mimic Schrödinger’s equation of the electrons, once in a topological state and once in a trivial (i.e. standard) state. By comparing small differences in the pendulum motion between the two experiments, the researchers could classify the two states. The classification required a very delicate measurement of a difference between the two experiments of exactly half a period of oscillation of a single pendulum after 400 full oscillations that lasted 12 minutes. This small difference was found to be consistent with the theoretical prediction.     The experiment opens the door to realizing further situations that are even more interesting and complex, like the effects of noise and impurities, or how energy leakage affects wave dynamics in Schrödinger’s equation. These are effects that can be easily realized and seen in this system, by deliberately perturbing the pendula motion in a controlled manner.

Bye Bye Birdie: How Will Crows Survive Without Us?

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When the Humans Are Away, Do the Crows Still Play?

A new study from Tel Aviv University examined what happens to birds that are accustomed to living around humans, when their habitat is suddenly emptied of the presence of humans. The study found that when humans are suddenly absent from the urban environment, the activity of the crows and ringneck parakeets that “live” in the area reduces significantly. Conversely, the graceful prinias, who are generally considered shy, increased their activity.  

Bird’s Eye View

Among other birds, the researchers tested crows, ringneck parakeets (also known as rose-ringed parakeets) and graceful prinias – and the findings are surprising: while the crows and ringneck parakeets, who are characterized by their tendency to “follow” humans, are already accustomed to the noises they make and feed on their food scraps, decreased their activity, the graceful prinias, which are considered shy, actually increased their activity in the same area.   A prinia bird leaninn on a branch A prinia bird leaninn on a branch.   The research was conducted under the leadership of research student Congnan Sun, Dr. Arjan Boonman and Prof. Yossi Yovel, head of The Sagol School of Neuroscience and a member of The School of Zoology at TAU, in collaboration with Prof. Assaf Shwartz from the Landscape Architecture Department at the Technion. The study’s results were published in ELIFE magazine.  

Birdemic: A Lockdown Story

As part of the current study, the researchers took advantage of the first COVID-19 lockdown to test the interrelationship between man and nature, and placed 17 recording wide-band sensitive microphones in the Yarkon Park and the streets adjacent to it in northern Tel Aviv. With the help of artificial intelligence, an analysis of the recordings from the first days of the lockdown until 10 days after its end (March 25 to May 28) showed that the activity of the crows and ringneck parakeets was significantly lower (the calls from the crows in the park decreased by about 50% during the lockdowns and the chirping of ringneck parakeets in the park dropped by about 90%). In contrast, the graceful prinias actually benefited from the absence of people and increased their presence by about 12%.   Prof. Yossi Yovel explains: “When the first COVID-19 lockdown began, we, like many researchers, in many fields, identified a rare opportunity to conduct field experiments that would examine how animals behave in the absence of humans. In general, many studies indicated the return of species to habitats that humans had ‘abandoned’ because of the coronavirus, but most of these studies were carried out through human observation, which obviously requires humans, who are, as mentioned, the factor whose effect we want to examine. We decided to use microphones to allow us to monitor the activity of birds while humans aren’t present, and to disperse them densely throughout parks and residential neighborhoods. We chose the Yarkon Park area, heading south until Arlozorov Street, and we placed 17 microphones at a distance of about 500 meters away from each other. We chose the ‘old north’ neighborhood of Tel Aviv because it is an urban area adjacent to a park, to enable a comparison between the activity of the birds in a park and the activity of the birds in a city”.   Cry of the Crow The researchers examined the changes in the presence of three particularly common and particularly loud bird species, which differ from each other in the extent to which they exploit humans: hooded crow, ringneck parakeet and graceful prinia. The hooded crow is classified as a “human-following species,” that is, it stays near humans and feeds on their food scraps. The ringneck parakeet is an invasive species, it also follows humans. The graceful prinia is classified as “adaptive” – it adapts itself to humans, and knows how to get along in an urban environment, but does not feed on humans’ food scraps and prefers to avoid their company.     In total, the researchers recorded 3,234 hours containing around 250,000 bird calls, using artificial intelligence to identify the calls and the birds that made them. During the lockdown, human activity in the residential areas increased by 49% and human activity in the Yarkon Park – while leaving homes to go to parks was still prohibited – decreased by 31%.   “First, we found that the overall activity of the birds, regardless of COVID-19, is 53% higher in the parks than in the streets adjacent to them”, explains Prof. Yuval. “The parks are a center of activity for birds, and that is always true. On the other hand, a complex picture emerges from the lockdown period. The crows and ringneck parakeets, which usually subsist on leftover food from people in the park, searched for other avenues. The calls from the crows in the park decreased by about 50%, and the chirping of the ringneck parakeets in the park dropped by around 90%. Conversely, the shy graceful prinia, an outstanding adaptor, increased its activity by about 12%. These findings highlight the fact that there are animals that depend on us in the city, as well as the flexibility of these animals and the complexity and diversity of the urban ecosystem”.

Revolutionizing Plant Cloning: Boosting Global Agriculture?

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Can better rooting in plant cloning improve crop variety, cost, and climate resilience?

In an extensive and multi-phased international study that lasted for eight years, led by researchers from the School of Plant Sciences and Food Security at TAU and the Volcani Institute, there were new compounds developed that significantly increased the rooting efficiency of cuttings (typically small branches) taken from mature trees. The researchers explain that getting cuttings to root is a critical component in modern agriculture: “A significant number of fruit trees, as well as forest trees and ornamental plants, are today based on cutting propagation: the creation of plants that are genetic clones of an individual with desirable characteristics. Improving the rooting process can contribute to global agriculture in various aspects: developing new, high-quality varieties, lowering prices for farmers and consumers, increasing the economic viability of new cultivars of crops, and adapting crops to the changing climate conditions”.

Enhancing Nature

The research was led by Dr. Roy Weinstain, research student Ohad Roth from the School of Plant Sciences and Food Security at TAU and Dr. Einat Sadot from the Institute of Plant Sciences at the Volcani Institute. Also participating in the research were Dr. Inna Vints from the TAU School of Plant Sciences and Food Security, Prof. Nir Ben-Tal and Dr. Amit Kessel from the Department of Biochemistry and Molecular Biology at TAU, Sela Yechezkel, Ori Serero, Avi Eliyahu, Pan Tzeela, Dr. Vikas Dwivedi, Dr. Mira Carmeli-Weissberg, Felix Shaya, and Dr. Adi Faigenboim-Doron from the Volcani Institute and Prof. Joseph Riov from the Faculty of Agriculture of the Hebrew University of Jerusalem. The study was in collaboration with researchers from the USA, Germany, Denmark and England and published in the prestigious journal Nature Biotechnology.

Left to right: Dr. Einat Sadot, Dr. Roy Weinstain, Ohad Roth & Sela Yechezkel. Photo credit: The Volcani Institute.

Left to right: Dr. Einat Sadot, Dr. Roy Weinstain, Ohad Roth & Sela Yechezkel. Photo credit: The Volcani Institute.

Dr. Sadot explains: “vegetative propagation through cuttings is a method used to propagate plants asexually – not through seeds. In this method, a branch is selected from a plant with desirable properties (e.g. fruit taste, drought resistance, disease resistance, etc.), and parts of that branch, called cuttings or propagules, are exposed to conditions that cause them to grow roots and become independent plants. The new individuals created this way were actually clones with the same genetics as the mother plant. For a crop to be economically viable, rooting percentages of at least 50-60% are necessary, and this figure is a significant consideration for farmers. Rooting percentages vary between different genuses of the same family, between different species of the same genus, and even between different cultivars of the same species, and there are important agricultural plants that are particularly difficult to root”.

Cutting-Edge, Literally

To improve the percentage of plants developing roots, it is necessary to expose cuttings to the plant hormone auxin – a procedure that was discovered more than 70 years ago and has hardly changed since. Dr. Weinstain: “The effectiveness of the existing auxin treatment varies from plant to plant. Numerous agriculturally important plants hardly respond to the standard auxin treatment in terms of root formation that couldn’t be commercialized. In our study, we sought to increase the effect of auxin on the cuttings. Evidence in the scientific literature and observations by experts in the field led us to address the question: will a slow release of the auxin in the plant increase the rooting success of the cuttings?” To do this, the researchers first created a ‘library’ of materials based on synthetic auxin conjugates – molecules in which a synthetic auxin attaches to another chemical group that neutralizes its activity but can be released slowly in plant cells. The library was examined using cuttings from a mature Eucalyptus grandis tree, in which the standard auxin treatment reached low rooting percentages of only 10-15%.

Research student Ohad Roth explains: “The initial examination identified several compounds that have a positive effect on the rooting process, and further research focused on the most effective one. We discovered that this compound enables a combination of high permeability to the plant with a prolonged release of the active substance, the synthetic auxin, so that the auxin stays in the plant much longer, up to a week and a half”. Indeed, the upgraded treatment increased the rooting percentage of the Eucalyptus grandis cuttings to 60% – up to 6 times higher than the rooting percentages found using the standard method.

Later, to more deeply understand the new compound’s mode of action, the researchers used the model plant Arabidopsis thaliana. They discovered that the synthetic auxin used in the new material is more stable (breaks down more slowly) in the plant cells compared to the auxin used in the standard treatment. In addition, the researchers identified a family of enzymes in the plant that are responsible for the release of the synthetic auxin. By modeling these enzymes’ structure and biochemical properties, they have identified important characteristics of their activity.

In the next step, the researchers wanted to see if similar enzymes are also present in other plants – assumingly their presence will allow the new material to be used as well as in other crops. They discovered that this family of enzymes is very ancient and preserved throughout evolution in every tree tested. In light of the encouraging findings, they began to test the effectiveness of the materials they developed on various crops.

Transforming Argan Trees to Agricultural Crops

One of the most meaningful crops examined in the study is the argan – the Moroccan oil tree. The researchers: “The global demand for argan oil is increasing by the years because of its incorporation to a large variety of food, health and skincare products. But to date, the almost exclusive source of this oil is the fruits of argan trees that grow endemically in Morocco and multiply by sexual reproduction, i.e. through seeds. All efforts to turn argan into an agricultural crop, which can be propagated by rooting cuttings, have failed – including attempts here in Israel. In our research, we took cuttings from several argan trees growing in Israel, exposed them to the material we developed, and, this way, succeeded in producing large seedlings from elite selections. In collaboration with the Kibbutzim of Ketura, Beit Kama, Hatzerim and Samar, we planted argan plots based on cuttings from individual specimens, which were rooted using the new rooting material, and we are now examining the possibility of turning them into an agricultural crop”.

The Beautiful Argan Tree

Encouraging results were also observed in experiments with cuttings from apple trees rootstocks, poplar and other varieties of eucalyptus. Higher rooting percentages were achieved in all of them – twice as high or more when compared to the standard auxin treatment. The researchers conclude: “During the research, we developed a material that significantly improves the rooting percentages of cuttings from mature trees. The development could be significant for global agriculture in three aspects:

● Cost reduction: improving the efficacy of the rooting procedure may significantly reduce the cost of procuring seedlings for farmers and, ultimately, the agricultural produce for consumers.

● Improved produce quality: Thanks to the new method, more high-quality cultivars could developed and traded, negating the need to ‘compromise’ on lower-quality varieties simply because they have high rooting rates.

● Environmental compatibility: developing new crop cultivars that adapt to climate change conditions is imperative to sustain agricultural output. The new method can expedite this process and make it more efficient.

In follow-up studies, we plan to deepen the understanding of the new substances’ mechanisms of action and look for additional compounds, perhaps even more effective ones, that can be used as conjugates to slow down the release of auxin in the plant.”

A Scientific Breakthrough That Will Help Increase Plant Yields in Dry Conditions

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Using CRISPR technology, researchers succeed in growing tomatoes that consume less water without compromising yield.

A new discovery by Tel Aviv University has succeeded in cultivating and characterizing tomato varieties with higher water use efficiency without compromising yield. The researchers, employing CRISPR genetic editing technology, were able to grow tomatoes that consume less water while preserving yield, quality, and taste.

The research was conducted in the laboratories of Prof. Shaul Yalovsky and Dr. Nir Sade, and was led by a team of researchers from the School of Plant Sciences and Food Security at Tel Aviv University’s Wise Faculty of Life Sciences. The team included Dr. Mallikarjuna Rao Puli, a former postdoctoral fellow supervised by Prof. Yalovsky, and Purity Muchoki, a doctoral student jointly supervised by Prof. Yalovsky and Dr. Sade. Additional students and postdoctoral fellows from TAU’s School of Plant Sciences and Food Security, along with researchers from Ben Gurion University and the University of Oregon, also contributed to the research. The study’s findings were published in the academic journal PNAS.

The researchers explain that in light of global warming and the diminishing of freshwater resources, there is a growing demand for agricultural crops that consume less water without compromising yield. Naturally, at the same time, because agricultural crops rely on water to grow and develop, it is particularly challenging to identify suitable plant varieties.

In a process called transpiration, plants evaporate water from their leaves. Concurrently, carbon dioxide enters into the leaves, and is assimilated into sugar by photosynthesis, which also takes place in the leaves. These two processes — transpiration and carbon dioxide uptake — occur simultaneously through special openings in the surface of leaves called stomata. The stomata can open and close, serving as a mechanism through which plants regulate their water status.

The researchers highlight that under drought conditions, plants respond by closing their stomata, thereby reducing water loss by transpiration. The problem is that due to the inextricable coupling between the transpiration of the water and the uptake of carbon dioxide, the closing of the stomata leads to a reduction in the uptake of carbon dioxide by the plant. This decrease in carbon dioxide uptake leads to a decline in the production of sugar by photosynthesis. Since plants rely on the sugar generated in photosynthesis as a vital energy source, a reduction in this process adversely affects plant growth.

In crop plants, the decline in photosynthetic sugar production manifests as a decline in both the quantity and quality of the harvest. In tomatoes, for example, the damage to the crop is reflected in a decrease in the number of fruits, their weight, and the amount of sugar in each fruit. Fruits with lower sugar content are less tasty and less nutritious.

In the present study, the researchers induced a modification in the tomato through genetic editing using the CRISPR method, targeting a gene known as ROP9. The ROP proteins function as switches, toggling between an active or inactive state.

Prof. Yalovsky: “We discovered that eliminating ROP9 by the CRISPR technology cause a partial closure of the stomata. This effect is particularly pronounced during midday, when the rate of water loss from the plants in the transpiration process is at its highest. Conversely, in the morning and afternoon, when the transpiration rate is lower, there was no significant difference in the rate of water loss between the control plants and ROP9-modified plants. Because the stomata remained open in the morning and afternoon, the plants were able to uptake enough carbon dioxide, preventing any decline in sugar production by photosynthesis even during the afternoon hours, when the stomata were more closed in the ROP9-modified plants.”

To assess the impact of the impaired ROP9 on the crop, the researchers conducted an extensive field experiment involving hundreds of plants. The results revealed that although the ROP9-modified plants lose less water during the transpiration process, there is no adverse effect on photosynthesis, crop quantity, or quality (the amount of sugar in the fruits). Furthermore, the study identified a new and unexpected mechanism for regulating the opening and closing of the stomata, related to the level of oxidizing substances, known as reactive oxygen species, in the stomata. This discovery holds significant implications for basic scientific knowledge as well.

Dr. Sade: “There is great similarity between the ROP9 in tomatoes and ROP proteins found in other crop plants such as pepper, eggplant and wheat. Therefore, the discoveries detailed in our article could form the basis for the development of additional crop plants with enhanced water use efficiency, and for a deeper understanding of the mechanisms behind stomatal opening and closing.”

Head of Science at the Chan Zuckerberg Initiative Meets TAU’s Scientific Community

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Prof. Stephen Quake visited Tel Aviv University and talked about science and collaboration.

Prof. Stephen Quake, the head of science at the Chan Zuckerberg Initiative, visited Tel Aviv University recently and met with its leading scientists.

CZI, which was founded by Facebook’s co-founder Mark Zuckerberg and his wife Priscilla Chan in 2015, is looking to diversify and expand its scientific grant programs, and Quake’s visit was an important step in building cooperation between the Intitative’s and the University’s science communities.

 

“Mark and Priscilla’s goal is to cure, manage or treat all human disease over the course of the century.” 

 

“Mark and Priscilla have decided to give their entire fortune away in their lifetime. Their goal is to achieve a lot … and in science it is to cure, manage or treat all human disease over the course of the century—to try to stimulate the global research community to do it,” said Quake upon being interviewed on Tel Aviv University’s podcast channel, TAU Unbound.

To achieve that, Quake said, CZI’s decision has been “to focus on basic science for a couple of decades—that’s where we think transformative breakthroughs will come from.”

 

 

Currently, CZI is funding research through grants in about 30 different countries, including 9 in Israel. Grant support is given in five broad areas: cell biology, neuroscience, imaging, rare diseases and genome science, and open science, explained Quake.

Another way CZI is catalyzing breakthroughs is by establishing bio-hubs—institutes that partner with “great universities” to take on “a big decade-long problem that they wouldn’t do on their own, be a nexus for driving that collaboration.” For now, CZI has two institutes based in the US, but may consider opening an international bio-hub in the future. “Nobody has all the answers themselves, science goes faster when you share knowledge,” said Quake replying to a question about why international collaboration is important. In the podcast, he also outlined the procedure and criteria for CZI’s grant-giving.

Besides speaking on the podcast, Prof. Quake and the CZI delegation met with a group of TAU’s leading scientists headed by Prof. Dan Peer, TAU’s VP of Research& Development, as well as with the University’s President Prof. Ariel Porat, and the VP for Resource Development, Amos Elad.

“TAU is looking forward to expanding collaboration with the Chan Zuckerberg Initiative, which is an amazing organization with the potential to do great things for humanity,” said President Ariel Porat. 

Researchers Produce Highly Efficient, Low-cost “Green” Hydrogen

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Initial hope for mass production of green hydrogen, which will dramatically reduce global CO2 emissions.

Tel Aviv University researchers have achieved a groundbreaking milestone by successfully producing highly efficient and low-cost “green” hydrogen. By harnessing the power of green electricity and utilizing a highly efficient biocatalyst, this innovative process generates hydrogen without any air pollution.

Hydrogen plays a vital role as raw material in both agriculture and industry. However, most of the hydrogen produced globally, approximately 95%, falls in the “black” or “gray” category. These types of hydrogen are derived from coal or natural gas, emitting a significant 9-12 tons of carbon dioxide for every ton of hydrogen produced.

Over 90% Efficiency

The new method was developed by doctoral student Itzhak Grinberg and Dr. Oren Ben-Zvi, under the guidance of Prof. Iftach Yacoby of the School of Plant Sciences and Food Security at the Faculty of Life Sciences and Prof. Lihi Adler-Abramovich of the School of Dental Medicine and the Center for Nanoscience and Nanotechnology. The promising research results were published in the prominent journal Carbon Energy, focusing on advanced materials and technology for clean energy and CO2 emission reduction.

“Hydrogen is very rare in the atmosphere,” explains Itzhak Grinberg, “although it is produced by enzymes in microscopic organisms, which receive the energy for this from photosynthesis processes. In the lab, we ‘electrify’ those enzymes, that is, an electrode provides the energy instead of the sun. The result is a particularly efficient process, with no demand for extreme conditions, that can utilize electricity from renewable sources such as solar panels or wind turbine. However, the enzyme ‘runs away’ from the electric charge, so it needs to be held in place through chemical treatment. We found a simple and efficient way to attach the enzyme to the electrode and utilize it.”

The researchers used a hydrogel (a water-based gel) to attach the enzyme to the electrode and were able to produce green hydrogen using a biocatalyst, and with over 90% efficiency; that is, over 90% of the electrons introduced into the system were deposited in the hydrogen without any secondary processes.

 

 

“We hope that in the future, it will be possible to employ our method commercially, to lower the costs, and to make the switch towards using green hydrogen in industry, agriculture, and as a clean energy source.” – Dr. Oren Ben-Zvi

 

Prof. Iftach Yacoby explains that, “The material of the gel itself is known, but our innovation is to use it to produce hydrogen. We soaked the electrode in the gel, which contained an enzyme for producing hydrogen, called hydrogenase. The gel holds the enzyme for a long time, even under the electric voltage, and makes it possible to produce hydrogen with great efficiency and at environmental conditions favorable to the enzyme — for example, in salt water, in contrast to electrolysis, which requires distilled water.

Prof. Lihi Adler-Abramovich adds: “Another advantage is that the gel assembles itself — you put the material in water, and it settles into nanometric fibers that form the gel. We demonstrated that these fibers are also able to stick the enzyme to the electrode. We tested the gel with two other enzymes, in addition to the hydrogenase, and proved that it was able to attach different enzymes to the electrode.”

“Today, ‘green’ hydrogen is produced primarily through electrolysis, which requires precious and rare metals such as platinum along with water distillation, which makes the green hydrogen up to 15 times more expensive than the polluting ‘grey’ one, says Dr. Oren Ben-Zvi. “We hope that in the future, it will be possible to employ our method commercially, to lower the costs, and to make the switch towards using green hydrogen in industry, agriculture, and as a clean energy source.”

Researchers Induce Cancer Cell “Suicide”

Written by AUFTAU on . Posted in Newsroom.

Tel Aviv University’s breakthrough study unleashes self-produced toxin, targeting and eliminating cancer cells with impressive results.

For the first time in the world: researchers at Tel Aviv University encoded a toxin produced by bacteria into mRNA (messenger RNA) molecules and delivered these particles directly to cancer cells, causing the cells to produce the toxin – which eventually killed them with a success rate of 50%.

 

“Our idea was to deliver safe mRNA molecules encoded for a bacterial toxin directly to the cancer cells – inducing these cells to actually produce the toxic protein that would later kill them. It’s like placing a Trojan horse inside the cancer cell.” – Prof. Dan Peer

 

“It’s like placing a Trojan horse inside the cancer cell”

The groundbreaking study was led by PhD student Yasmin Granot-Matok and Prof. Dan Peer, a pioneer in the development of RNA therapeutics and Head of the Nanomedicine Laboratory at The Shmunis School of Biomedicine and Cancer Research, also serving as TAU’s VP R&D. The study’s results were published in Theranostics.

Prof. Peer explains: “Many bacteria secrete toxins. The most famous of these is probably the botulinum toxin injected in Botox treatments. Another classic treatment technique is chemotherapy, involving the delivery of small molecules through the bloodstream to effectively kill cancer cells. However, chemotherapy has a major downside: it is not selective, and also kills healthy cells. Our idea was to deliver safe mRNA molecules encoded for a bacterial toxin directly to the cancer cells – inducing these cells to actually produce the toxic protein that would later kill them. It’s like placing a Trojan horse inside the cancer cell.”

Prof. Dan Peer

Impressive Results

First, the research team encoded the genetic info of the toxic protein produced by bacteria of the pseudomonas family into mRNA molecules (resembling the procedure in which genetic info of COVID-19’s ‘spike’ protein was encoded into mRNA molecules to create the vaccine). The mRNA molecules were then packaged in lipid nanoparticles developed in Prof. Peer’s laboratory and coated with antibodies – to make sure that the instructions for producing the toxin would reach their target, the cancer cells. The particles were injected into the tumors of animal models with melanoma skin cancer. After a single injection, 44-60% of the cancer cells vanished.  

 

“With a simple injection to the tumor bed, we can cause cancer cells to ‘commit suicide’, without damaging healthy cells. Moreover, cancer cells cannot develop resistance to our technology as often happens with chemotherapy – because we can always use a different natural toxin.” – Prof. Dan Peer

 

“In our study, the cancer cell produced the toxic protein that eventually killed it,” says Prof. Peer. “We used pseudomonas bacteria and the melanoma cancer, but this was only a matter of convenience. Many anaerobic bacteria, especially those that live in the ground, secrete toxins, and most of these toxins can probably be used with our method. This is our ‘recipe’, and we know how to deliver it directly to the target cells with our nanoparticles. When the cancer cell reads the ‘recipe’ at the other end it starts to produce the toxin as if it were the bacteria itself and this self-produced toxin eventually kills it. Thus, with a simple injection to the tumor bed, we can cause cancer cells to ‘commit suicide’, without damaging healthy cells. Moreover, cancer cells cannot develop resistance to our technology as often happens with chemotherapy – because we can always use a different natural toxin.”

Other contributors to the study included: Dr. Assaf Ezra, Dr. Srinivas Ramishetti, Dr. Preeti Sharma Dr. Gonna Somu Naidu and Prof. Itai Benhar, Head of the Antibody Engineering Lab at the Shmunis School of Biomedicine and Cancer Research at TAU. The study was funded by the Shmunis Family Foundation for Biomedicine and Cancer Research.

Metabolomics – A New Frontier in Preventive Medicine

Written by AUFTAU on . Posted in Newsroom.

Tel Aviv University’s new Metabolite Medicine Division at the BLAVATNIK Center for Drug Discovery poised to revolutionize the field.

Even the simplest blood tests of today – which monitor about 20 substances in our body – have powerful predictive and diagnostic power. For example, high cholesterol suggests possible heart trouble, and abnormal glucose could indicate pre-diabetes.

Now imagine that routine and low-cost bloodwork could check for thousands of compounds all at once, as well as calculate the balance between them. Such a real-time status check would provide doctors with unparalleled knowledge for diagnosing patients and creating personalized profiles for the most effective treatment of disease.

 

“Metabolomics is poised to revolutionize the field of preventive medicine. It holds tremendous potential (…) not only for detecting diseases but also for enabling individuals to proactively monitor their overall physiological well-being even before the onset of illness.” – Prof. Ehud Gazit

 

The Super Blood Test

We are entering such an era at TAU’s new Metabolite Medicine Division at the BLAVATNIK CENTER for Drug Discovery. This suite of labs is the most advanced at an Israeli university for the emerging science of metabolomics – the study of small molecules called metabolites that our bodies produce every second of our lives as part of ongoing cell processes. Sometimes, all that is required is to identify the one metabolite culprit that is throwing the body off balance.

“Metabolomics is poised to revolutionize the field of preventive medicine. It holds tremendous potential as a cornerstone and indispensable tool, not only for detecting diseases but also for enabling individuals to proactively monitor their overall physiological well-being even before the onset of illness,” explains Prof. Ehud Gazit, the Founding Director of the Metabolomic Medicine division.

“Unlike genetics, which cannot be easily altered, the composition of metabolites provides a valuable reflection of the body’s physiological state, making it possible to optimize towards an ideal state through dietary interventions, physical activity, and lifestyle modifications,” he says. 

 

“The establishment of the Metabolite Medicine division at the BLAVATNIK CENTER for Drug Discovery is highly important for the entire biomed framework of Tel Aviv University.” – Dr. Ludmila Bozhansky

 

Driving Real-Life Implementation

Using state-of-the-art equipment, scientists will be able to identify specific metabolic signatures in laboratory and patient cell culture samples, learn about their mechanisms of action, and develop AI-aided data analysis tools. The ultimate aim of the Metabolite Division is to connect promising university discoveries with Israeli hospitals for clinical samples and testing, and with the pharma industry for creating or repurposing drugs. 

“The establishment of the Metabolite Medicine division at the BLAVATNIK CENTER for Drug Discovery is highly important for the entire biomed framework of Tel Aviv University,” says Dr. Ludmila Buzhansky, the Managing Director of the BLAVATNIk Center for Drug Discovery. “By leveraging the capabilities of metabolomics and benefiting from the exceptional expertise now available at TAU in this field, our researchers develop interdisciplinary collaborations that drive innovation and knowledge dissemination across diverse domains within the university community and beyond.”

Source: TAU Review

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