Scientists develop sugar-coated nanosheets to target pathogens

Molecular Foundry-designed 2-D sheets mimic the surface of cells

Researchers have developed a process for creating ultrathin, self-assembling sheets of synthetic materials that can function like designer flypaper in selectively binding with viruses, bacteria, and other pathogens.
In this way the new platform, developed by a team led by scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), could potentially be used to inactivate or detect pathogens.

The team, which also included researchers from New York University, created the synthesized nanosheets at Berkeley Lab’s Molecular Foundry, a nanoscale science center, out of self-assembling, bio-inspired polymers known as peptoids. The study was published earlier this month in the journal ACS Nano.
The sheets were designed to present simple sugars in a patterned way along their surfaces, and these sugars, in turn, were demonstrated to selectively bind with several proteins, including one associated with the Shiga toxin, which causes dysentery. Because the outside of our cells are flat and covered with sugars, these 2-D nanosheets can effectively mimic cell surfaces.

>Read more on the Advanced Light Source website

Image: A molecular model of a peptoid nanosheet shows loop structures in sugars (orange) that bind to the Shiga toxin (shown as a five-color bound structure at upper right).
Credit: Berkeley Lab

Study reveals mechanism in spruce tree that causes growth

While it’s common knowledge that trees grow when days start to become longer in the springtime and stop growing when days become shorter in the fall, exactly how this happens has not been well understood.

Now, scientists using the Canadian Light Source are offering insights into the mechanisms of how certain cells in the winter buds of Norway spruce respond to changes in seasonal light, affecting growth. The research was published in Frontiers in Plant Science.

Such knowledge allows for better predictions of how trees might respond to climate change, which could bring freezing temperatures while daylight is still long or warmer temperatures when daylight is short.

Professor Jorunn E. Olsen and YeonKyeong Lee, plant scientists at the Norwegian University of Life Sciences, along with colleagues from the University of Saskatchewan investigated winter bud cells from Norway spruce and how they differ with respect to the amount of daylight to which they were exposed.

>Read more on the Candian Light Source website

Image (from left to right, extract): plant with terminal winter bud after short day exposure for three weeks; plant with brown bud scales after short day exposure for eight weeks; plant showing bud break and new growth three weeks after re-transfer to long days following eight weeks under short days. Entire picture here.

Supporting World Cancer Day 2018

Diamond is proud to be supporting World Cancer Day and highlighting our role, working with our user community, in pioneering synchrotron research in every area of cancer – from developing a better understanding of how cancer cells work to delivering new cancer therapies.
Despite major advances in diagnosis and treatment, cancer still claims the lives of 8.8 million people every year around the world. About 4 million of these die prematurely (under the age of 70). World Cancer Day aims to raise the awareness of cancer and its treatment around the world. With the tagline ‘We can. I can.’, World Cancer Day is exploring how everyone can play their part in reducing the global burden of cancer.

Diamond has published over 900 publications in the last 12 months, with around 10% of these focusing on cancer. The wide-ranging research currently covers at least 12 cancer types, with many more general studies on the structure of cancer cells and pathways, potential drug targets and possible drug candidates. Building on last year’s review of some of the key studies in cancer that have taken place at Diamond, here is an update on studies that have been published in the last 12 months.

>Read more on the Diamond Light Source website

 

Modified antibody clarifies tumor-killing mechanisms

The structure of an antibody was modified to selectively activate a specific pathway of the immune system, demonstrating its value in killing tumor cells.

Immunotherapy—the use of the immune system to fight disease—has made tremendous progress in the fight against cancer. Antibodies such as immunoglobulin G (IgG) can identify and attack foreign or abnormal substances, including tumor cells. But to control and amplify this response, scientists need to know more about how elements of the immune system recognize tumor cells and trigger their destruction. There are two main pathways for this: antibody-dependent mechanisms and complement-dependent mechanisms.

The antibody pathway involves coating the surfaces of tumor cells with antibodies that recruit “natural killer” (NK) cells and macrophages (a type of white blood cell) to destroy the tumor cells. The complement pathway (so named because it complements the antibody pathway) also engages NK cells and macrophages and includes a third mechanism—a cascade of events culminating in tumor-cell destruction via a membrane attack complex (MAC).

>Read more on the ALS webpage

Image: extract of a schematic illustration (see on the ALS webpage)

Malaria in Action

Seeing the invisible

In 2007 Helen Saibil was at a conference in Australia. Amongst the presentations there happened to be talks on the parasites malaria and toxoplasma and how they infect mammalian cells, causing disease. Helen is a structural biologist and whilst listening she began to realise that her newly acquired skills -she was doing electron tomography of cells- might allow the researchers to see things they had never seen before.

Electron tomography reveals structures in the interiors of cells in great detail. What she hoped was that it could be used to look at the malaria parasites inside red blood cells [See images below] to get a better understanding of what they do there. Helen approached one of the speakers, Mike Blackman, then at the National Institute for Medical Research at Mill Hill in London, and so began a thriving collaboration. One that has produced the remarkable pictures of malaria parasites breaking out of infected human red blood cells on this page.

Helen Saibil and her colleagues used electron tomography to peer into malaria infected cells, looking at the parasites hiding and multiplying inside. The technique produces exquisitely detailed pictures able to reveal very tiny features, but it has one big drawback. Electrons cannot penetrate deep into the sample so it only works on very thinly sliced samples, much thinner than an individual cell. As a result it cannot be used to look at entire cells, or in this case red blood cells containing malaria parasites.

>Read more on the Diamond Light Source website