All Scientific Activities

Zebrafish imaging and cancer

One Weizmann Institute scientist is making critical advances in studying the lymphatic system, a mechanism involved in the metastatic spread of cancer cells, by conducting live imaging experiments in zebrafish embryos.

Prof. Karina Yaniv, along with her team members in the Department of Biological Regulation, have long focused on uncovering the origins of lymphatic vessels during embryonic development.

Read More about Zebrafish imaging and cancer

Light on brain chemistry

Using an innovative method to switch the electrical impulses of brain cells on and off with pulses of light, Weizmann Institute scientists are now obtaining reliable structural and spectroscopy data from mouse brain tissue. The new, experimental protocol relies on optogenetics, a genetic engineering technology that can control the brain with light. 

Dr. Assaf Tal, from the Department of Chemical Physics, and Dr. Ofer Yizhar, from the Department of Neurobiology, combined their expertise to develop a method based on magnetic resonance spectroscopy, which makes it possible to visualize how the brain’s neurochemical profile changes in response to selective optogenetic light pulses. While the scientists began by working with computer simulations, they are now planning to conduct similar studies on live mice, in order to determine how the chemistry of the brain transforms in real time.

Read More about Light on brain chemistry

The way proteins gossip

Just like office employees often congregate to “gossip around the coffee machine”, so do many proteins. According to the findings of Dr. Emmanuel Levy from the Department of Structural Biology, proteins often interact “promiscuously” with one another.

During his postdoctoral work at the University of Montreal, Dr. Levy showed how key proteins alter their chemical properties to minimize their promiscuous interactions.  Now, Dr. Levy is devising new ways to understand how promiscuous interactions evolve. Ultimately, he hopes to better understand how proteins are organized within cells, and use this knowledge to treat cells in diseased states.

Read More about The way proteins gossip

Single-celled architects

In nearly every ecological niche across the Earth, single-celled algae, called diatoms, are hard at work crafting elaborate cell walls at a nanometer scale. As they produce exceedingly thin layers of silica - a material similar to common glass - diatoms are building walls through methods unrivaled by any human technique. While the potential biotechnological applications for such a mechanism are plentiful, scientists have struggled to mimic the process due to the insolubility and short-lived nature of the inorganic materials involved.

Read More about Single-celled architects

Neuroimaging and artificial networks

While the in-vivo imaging of cerebral vasculature has long been vital to medical scientists, the expensive, invasive nature of existing technologies has hampered the advancement of brain studies. 

Dr. Vyacheslav Kalchenko is working to change this reality. Together with his colleagues at the In Vivo Optical Imaging Unit, he has successfully developed a simple approach that utilizes standard fluorescent imaging protocol, inexpensive micro imaging, and computation procedures to provide a clear and accessible picture of the brain’s vascular network.

Read More about Neuroimaging and artificial networks

The first line of defense against invaders

Certain cytokines – the proteins responsible for conveying signals into the cell from the external environmental – play a critical role as protectors against foreign invaders. After a cytokine binds to the portion of a receptor protein located outside the cell, a signal is transferred inside for further processing. Particularly of interest to scientists is the potential to obtain a variable set of outcomes from the same cytokine, depending on the biophysical and cellular parameters of receptor activation.

Read More about The first line of defense against invaders

Tracking migration of white blood cells

Equipped with a state-of-the-art, live imaging fluorescent microscope, Prof. Ronen Alon is tracking the differences in migration routes of white blood cells (leukocytes), as they travel from the bloodstream to specific inflammation sites. Visualizing these routes, and the complex mechanisms governing them, may offer vital information as to why leukocyte response to a variety of medical conditions can sometimes be weakened.

Read More about Tracking migration of white blood cells

Looking at neuronal connectivity

As the human brain processes sensory information, coordinates motor activity, and stores and retrieves memories, a large number of molecules are working in concert to fine-tune the activity of the individual neurons that govern circuit connectivity.

A slight change in the function of one of these molecules, however, could lead to devastating consequences such as uncontrolled electrical activity in the case of epilepsy or neuronal death in conditions like Parkinson’s or Alzheimer’s diseases. If this change occurs in the early stages of development, other harmful possible outcomes include mental retardation or autism.

Read More about Looking at neuronal connectivity

Cell invasion and cancer metastasis

Living cells display an extraordinary capacity to sense the chemical and physical properties of the extracellular environment, and respond to environmental cues by altering their fate and behavior. Behind these interactions - particularly the adhesion of living cells to one and other, and to their surrounding environment - are a number of complex molecular mechanisms that likely contribute to the spread of cancer.

Prof. Benjamin Geiger from the Department of Molecular Cell Biology is investigating the role of cell-matrix and cell-cell adhesions in regulating collective cell migration. 

Read More about Cell invasion and cancer metastasis

Metals and cancer growth

While modern electron microscopy excels in visualizing cell structure, it is very poor in distinguishing the molecular or atomic makeup of cellular components. Proteins, sugars, and lipids consist primarily of carbon, nitrogen, oxygen, and hydrogen in different proportions, but the process of image formation reduces this information to levels of gray.

​Many essential enzymatic processes depend on heavier metal ions such as zinc, calcium, or even iron. Conventional imaging cannot reveal these, while the tools that exist for atomic analysis require high doses of electron radiation that damage the delicate biological materials.

Read More about Metals and cancer growth

A multi-channel recording

In order to get a clearer picture of the formation of blood and lymphatic vessels during embryogenesis, Dr. Karina Yaniv, from the Department of Biological Regulation, is taking advantage of the genetic accessibility of zebrafish embryos.

Because these embryos develop externally, they provide a noninvasive opportunity to observe stage-by-stage development of the entire vascular system. To do so, Dr. Yaniv and her team rely on their ability to image live embryos at high-resolution, through sophisticated technology.

Read More about A multi-channel recording

The mystery of neural communication

Imaging the activities of a specialized nervous system membrane called myelin could provide critical insights into the formation of certain diseases like multiple sclerosis. Of particular interest is myelination, or the process of electrically insulating axons—nerve fibers that conduct electrical impulses—to promote the rapid and energy efficient propagation of action potentials.

Read More about The mystery of neural communication