This research, led by research scientist Chandani Limbad, PhD, found that cellular senescence in astrocytes downregulates the glutamate transporters, which are vital for glutamate homeostasis in the brain. Glutamate is one of the most important neurotransmitters in the brain; an excess of it causes neurons to repeatedly fire leading to their eventual death. Memantine, an FDA-approved drug for Alzheimer’s disease, reduces glutamate toxicity in patients suffering from moderate to severe disease for up to a year, but evidence that the drug might slow pathology is weak. “This study gets to the underlying mechanisms that drive the toxicity,” said senior author and Buck professor Judith Campisi, PhD. “We have identified targets that may be of more use in drug development.”

Cellular senescence is one of the hottest topics in research on aging. Success in the Campisi lab and others around the world has given rise to companies and research projects aimed at developing either senolytics, drugs that clear senescent cells, or senomorphics, drugs that suppress the senescence-associated inflammation. Earlier work in the Campisi lab in collaboration with the Buck Institute’s Andersen lab showed that clearing senescent cells prevented Parkinson’s in a mouse model of the disease.

Campisi says that most of the research aimed at understanding the characteristics of cellular senescence involves human fibroblasts, cells in connective tissue which produce collagen and other fibers. She says this work in astrocytes should be a wake-up call to those studying Alzheimer’s disease, arguing that, “What is commonly termed non-familial Alzheimer’s disease should probably more accurately be termed age-related dementia. If you see five spontaneous Alzheimer’s patients, all of them present differently. Some have personality changes, others don’t. Memory is affected differently in each patient; some people lose motor control, others don’t. These findings highlight aging as the biggest risk factor for almost all neurodegeneration and that is where the research should be focused.”

Co-author Pierre-Yves Desprez, PhD, a scientific consultant in the Campisi lab, who also runs a lab at the California Pacific Medical Center Research Institute, says the research also has implications for those studying glioblastoma, a particularly aggressive form of brain cancer which happens in astrocytes. “Cellular senescence is a double-edged sword and the current state of senescence-associated research is messy. While senescence leads to chronic inflammation which promotes cancer and neurodegeneration, it also acts as a tumor suppressor. There are many factors secreted by senescent astrocytes, we think some of them could be exploited as a way to treat glioblastoma.”

The research, which involved unbiased RNA sequencing of transcripts expressed by senescent and non-senescent astrocytes, found changes in the expression of more than 5,000 genes whose functions are important in cancer, infectious diseases, and neurological diseases. Results are available to the research community.

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Materials provided by Buck Institute for Research on Aging. Note: Content may be edited for style and length.

For many forests, fire is as essential as rainfall. But while several studies have outlined the benefits of human-controlled prescribed burns on forest ecosystems, little was understood about how prescribed burns, or fires in general, may impact pollinators.

“There is global concern about the decline of insects in general, and pollinators in particular, so it’s really important for land managers to understand how prescribed fire affects insect communities,” says Elsa Youngsteadt, co-author of a paper on the work and an assistant professor in NC State’s Department of Applied Ecology.

“Given the importance of fire in maintaining longleaf pine ecosystems overall, you would expect it to be good for the region’s native bees. But it’s also easy to imagine small bees and their nests, especially nests in twigs and stems, just getting incinerated. We weren’t sure where we would find the most robust pollinator community.”

NC State researchers worked with the Walthour-Moss Foundation’s longleaf pine savannah reserve, which was established to protect this endangered pine. The reserve regularly burns 90% of its plots in 3-year cycles, while the remaining 10% of plots have not been burned for at least 50 years. This provided an ideal opportunity to compare bee abundance and diversity between unmanaged and managed ecosystems.

“The southeastern U.S. has some of the highest lightning strike rates in the world, which used to contribute to low-intensity fires passing through the longleaf pine savannas every 2 or 3 years,” Youngsteadt says. “But agriculture, development, and logging fragmented this landscape and blocked the movement of fire.”

For this study, researchers placed bee “traps” at 16 sites: four that had been burned the year of sampling, four that had been burned one year before sampling, four that had been burned two years before sampling, and four unburned control sites.

The researchers found that burned sites supported 2.3 times more total pollinators than plots that had not burned in 50 years. Burned sites also had 2.1 times as many different bee species as unburned sites. Within those burned areas, bee abundance and diversity tended to be greatest at sites that were most recently burned, and this abundance and diversity decreased with time since the last fire.

But why?

Fires maintain openings in the forest canopy, reduce ground cover and release nutrients into soils at the same time, creating the perfect environment for large blooms, increasing the flower resources pollinators rely on. The study also found that the low-intensity prescribed burns did not reduce the amount of nesting material for above-ground nesting pollinators, and the abundance of above-ground nesting pollinators was not impacted by the fires. Meanwhile, below-ground nesting species appeared to benefit from the increased access to bare soil.

“It’s great news that prescribed fire, as currently used in longleaf pine savannas, is helping to support the pollinator community,” Youngsteadt says. “But there’s still a lot to learn. For example, the fires in this study were set in the winter, but many land managers use summer burns. Knowing the effects of fire in different seasons will be an important next step, as will knowing the optimal area of land to burn at any one time.”

Around the world, each person eats an average of 70 pounds of the grain each year, with even more grown for animal feed and biofuel. And as the global population continues to boom, increasing the amount of food grown on the same amount of land becomes increasingly important.

One potential solution is to develop crops that perform better in cold temperatures. Many people aren’t aware that corn is a tropical plant, which makes it extremely sensitive to cold weather. This trait is problematic in temperate climates where the growing season averages only 4 or 5 months — and where more than 60% of its 1.6 trillion pound annual production occurs.

A chilling-tolerant strain could broaden the latitudes in which the crop could be grown, as well as enable current farmers to increase productivity.

A group of researchers led by David Stern, president of the Boyce Thompson Institute, have taken a step closer to this goal by developing a new type of corn that recovers much more quickly after a cold snap. Stern is also an adjunct professor of plant biology in Cornell University’s College of Agriculture and Life Sciences.

The research is described in a paper published online in Plant Biotechnology Journal on December 20.

This work built on research published in 2018, which showed that increasing levels of an enzyme called Rubisco led to bigger and faster-maturing plants. Rubisco is essential for plants to turn atmospheric carbon dioxide into sugar, and its levels in corn leaves decrease dramatically in cold weather.

In the latest study, Stern and colleagues grew corn plants for three weeks at 25°C (77°F), lowered the temperature to 14°C (57°F) for two weeks, and then increased it back up to 25°C.

“The corn with more Rubisco performed better than regular corn before, during and after chilling,” said Coralie Salesse-Smith, the paper’s first author. “In essence, we were able to reduce the severity of chilling stress and allow for a more rapid recovery.” Salesse-Smith was a Cornell PhD candidate in Stern’s lab during the study, and she is now a postdoctoral researcher at the University of Illinois.

Indeed, compared to regular corn, the engineered corn had higher photosynthesis rates throughout the experiment, and recovered more quickly from the chilling stress with less damage to the molecules that perform the light-dependent reactions of photosynthesis.

The end result was a plant that grew taller and developed mature ears of corn more quickly following a cold spell.

Steve Reiners, a co-team leader for Cornell Cooperative Extension’s vegetable program, says that sweet corn is a major vegetable crop in New York, worth about $40-$60 million annually. He notes that many New York corn growers plant as soon as they can because an early crop commands the highest prices of the season.

Reiners, who was not involved in the study, is also a professor of horticulture at Cornell.

“The corn we developed isn’t yet completely optimized for chilling tolerance, so we are planning the next generation of modifications,” said Stern. “For example, it would be very interesting to add a chilling-tolerant version of a protein called PPDK into the corn and see if it performs even better.”

The researchers believe their approach could also be used in other crops that use the C4 photosynthetic pathway to fix carbon, such as sugar cane and sorghum.

Co-authors on the paper include researchers from The Australian National University in Canberra.

The study was supported by the U.S. Department of Agriculture’s National Institute of Food and Agriculture (2016-67013-24464) and Australian Research Council Centre of Excellence for Translational Photosynthesis (CE1401000015).

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Materials provided by Boyce Thompson Institute. Original written by Aaron J. Bouchie. Note: Content may be edited for style and length.