Hexbyte Glen Cove Food scientists create national atlas for deadly listeria thumbnail

Hexbyte Glen Cove Food scientists create national atlas for deadly listeria

Hexbyte Glen Cove

Listeria, shown here in Martin Wiedmann’s laboratory, will be easier to trace in food recalls, thanks to a new genomic and geological mapping tool developed by a group led by Jingqiu Liao, Ph.D. ’20. Credit: Cornell University

Among the deadliest of foodborne pathogens, Listeria monocytogenes soon may become easier to track down in food recalls and other investigations, thanks to a new genomic and geological mapping tool created by Cornell food scientists.

The national atlas will tell scientists where listeria and other related species reside within the contiguous United States, which could help them trace and pinpoint sources of listeria found in ingredients, food processing facilities and finished products, according to research published July 15 in Nature Microbiology.

“As we’re trying to figure out the risk of getting listeria from soil and different locations, our group created a more systematic way of assessing how frequently different listeria are found in different locations,” said senior author Martin Wiedmann, Ph.D. ’97, the Gellert Family Professor in Food Safety and Food Science in the College of Agriculture and Life Sciences. “We’ve studied listeria in places as diverse as New York, Colorado and California, but before this atlas, [it] was difficult to make comparisons and assess listeria diversity in different locations.”

Listeria mononcytogenes in foods can make people extremely sick. The Centers for Disease Control and Prevention (CDC) estimate that each year 1,600 people in the U.S. get listeriosis; of those, about 260 die.

Knowing that listeria occurs naturally in soil, the Cornell group asked hundreds of other scientists across the country to scoop up from generally undisturbed places in the natural world, such as the off-trail areas of state and national parks.

From these samples, the group developed a nationwide atlas of 1,854 listeria isolates, representing 594 strains and 12 families of the bacteria called phylogroups.

Lead author Jingqiu Liao, Ph.D. ’20, who worked in Wiedmann’s laboratory as a graduate student, is now a post-doctoral researcher at Columbia University. She had supplemented the research by acquiring soil samples in her own travels and found listeria present across a wide range of environmental circumstances. This bacterium is controlled mainly by soil moisture, salinity concentrations and molybdenum—a trace mineral found in milk, cheese, grains, legumes, leafy vegetables and organ meats.

“The goal of this work was to systematically collect soil samples across the United States,” said Liao, “and to capture the true large-scale spatial distribution, genomic diversity and population structure of listeria species in the natural environment.

“With whole genome sequencing and comprehensive population genomics analyses,” Liao said, “we provided answers to the ecological and evolutionary drivers of bacterial genome flexibility—an important open question in the field of microbiology.”

Liao explained that this work can serve as a reference for future population genomics studies and will likely benefit the food industry by locating listeria contaminations that may have a natural origin.

If listeria is found in a processing facility in the western U.S., for example, and that facility had used ingredients from a distant state, Wiedmann said, “knowing the genomic information of listeria isolates and their possible locations across the U.S., we can better narrow the origins to a specific region. You can use this information almost like a traceback. It’s not always proof, but it leads you to evidence.”



More information:
Jingqiu Liao et al, Nationwide genomic atlas of soil-dwelling Listeria reveals effects of selection and population ecology on pangenome evolution, Nature Microbiology (2021). DOI: 10.1038/s41564-021-00935-7

Citation:
Food scientists create national atlas for deadly listeria (2021, August 6)
retrieved 9 August 2021
from https://phys.org/news/2021-08-food-scientists-national-atlas-deadly.html

Read More Hexbyte Glen Cove Educational Blog Repost With Backlinks —

Hexbyte Glen Cove More trees do not always create a cooler planet, geographer finds thumbnail

Hexbyte Glen Cove More trees do not always create a cooler planet, geographer finds

Hexbyte Glen Cove

Forest conversion from 1986 to 2000. Percentage of forest pixels converted, mapped at a 990 m x 990 m resolution. All cities with a population greater than 250,000 are displayed as black dots. Credit: Clark University Professor Christopher A. Williams

New research by Christopher A. Williams, an environmental scientist and professor in Clark University’s Graduate School of Geography, reveals that deforestation in the U.S. does not always cause planetary warming, as is commonly assumed; instead, in some places, it actually cools the planet. A peer-reviewed study by Williams and his team, “Climate Impacts of U.S. Forest Loss Span Net Warming to Net Cooling,” published today (Feb. 12) in Science Advances. The team’s discovery has important implications for policy and management efforts that are turning to forests to mitigate climate change.

It is well established that forests soak up from the air and store it in wood and soils, slowing the accumulation of greenhouse gases in the atmosphere; however, that is not their only effect on . Forests also tend to be darker than other surfaces, said Professor Williams, causing them to absorb more sunlight and retain heat, a process known as “the albedo effect.”

“We found that in some parts of the country like the Intermountain West, more forest actually leads to a hotter planet when we consider the full climate impacts from both and albedo effects,” said Professor Williams. It is important to consider the albedo effect of forests alongside their well-known carbon storage when aiming to cool the planet, he adds.

The research was funded by two grants from NASA’s Carbon Monitoring System. Williams and his research team—comprising data scientist Huan Gu, Ph.D. from The Climate Corporation and Tong Jiao, Ph.D.—found that for approximately one quarter of the country, forest loss causes a persistent net cooling because the albedo effect outweighs the carbon effect. They also discovered that loss of forests east of the Mississippi River and in Pacific Coast states caused planetary warming, while forest loss in the Intermountain and Rocky Mountain West tended to lead to a net cooling.

According to Professor Williams, scientists have known for some time that expanding forest cover cannot be assumed to cool the planet or to mitigate global warming. However, this has not always been appreciated broadly.

“If we fail to consider both the carbon and the albedo effects, large-scale tree-planting initiatives, such as Canada’s 2Billion Trees Initiative and The Nature Conservancy’s Plant a Billion Trees campaign, could end up placing trees in locations that are counterproductive for cooling the climate system,” said Professor Williams.

“It is all about putting the right trees in the right place,” said Williams, “and studies like ours can help identify where the potential for cooling is greatest.”

Every year, approximately one million acres of forest are being converted to non-forest areas across the lower 48 states of the U.S.; this is largely due to suburban and exurban expansion and development. Professor Williams’ team found that the net climate impact of a full 15 years of forest losses amounts to about 17% of a single year of U.S. fossil fuel emissions.

Clark University Professor Christopher A. Williams. Credit: Photographer Steven King

Williams’ research team used state-of-the-art satellite remote sensing to bring a detailed, observational perspective to examine this problem that had previously been assessed mostly with computer models. The three researchers pinpointed the locations of forest loss and identified what those sites became—urban, agricultural, grassland, shrubland, pasture, or something else. They then quantified how much biomass carbon was released to the atmosphere, and how much additional sunlight was reflected out to space. By comparing these two effects they measured the net impact of deforestation on the climate system.

The new datasets and methods used in Professor Williams’ study show that the tools are available to take the albedo effect into account. The Clark team hopes to generate actionable datasets to share with land managers and policymakers worldwide within the next one or two years, to help ensure that their tree-planting efforts focus on the right places and have the intended effects.



More information:
“Climate impacts of U.S. forest loss span net warming to net cooling” Science Advances (2021). advances.sciencemag.org/lookup … .1126/sciadv.aax8859

Provided by
Clark University

Citation:
More trees do not always create a cooler planet, geographer finds (2021, February 12)
retrieved 14 February 2021
from https://phys.org/news/2021-02-trees-cooler-planet-geographer.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

Read More Hexbyte Glen Cove Educational Blog Repost With Backlinks —