COLLEGE PARK, Md.—Worldwide, more and more countries are strategically investing to extend their natural resource base beyond their borders, frequently into developing countries. New research from the University of Maryland (UMD) finds that this global trend could put already-vulnerable populations at a higher risk for undernourishment and food insecurity.

The UMD study, recently published in the Journal of Cleaner Production, takes a close look at the increasingly common practice of land displacement—the use of land in one country to grow food and other crops to be consumed in another country. The research team analyzed the amount of agricultural land used for the production of crops traded between 133 countries and regions. Their findings show a link between large-scale land acquisitions (LSLAs)—frequently referred to as “land grabs”— and undernourishment in countries exporting their land-based resources.

“International trade is playing an unprecedented role in the distribution of food between countries around the world and is greatly impacting the global food supply,” said lead author Suzanne Marielle Marselis, a researcher in the UMD Department of Geographical Sciences. “In the case of land displacement, even if local food production may increase, it is often not available to the local population. Therefore, food insecurity and undernourishment are not a result of a lack of food, but a maldistribution of available food.”

The study authors note that undernourishment and food security are complex problems influenced by many factors other than land displacement including natural disasters, conflict, governance and fluctuations in demand and commodity prices. Proponents of agricultural land acquisitions argue that the practice leads to higher crop yields, technological innovation and job opportunities for local populations. Others argue the benefits are overshadowed by negative impacts such as depletion of natural resources, environmental degradation, loss of land available to smaller farmers and misappropriation of funds and food. Countries like Ethiopia, Malawi, Sudan, Madagascar, Cambodia and Kenya are currently center stage in the debate over the relationship between land grabs and food insecurity.

“We hope our findings can contribute to and move the debate forward and that further research will consider the impact of land displacement on poverty and undernourishment,” said study co-author Klaus Hubacek, a UMD Geographical Sciences Professor. “Stronger restrictions may be necessary to control LSLAs and mitigate the potential negative consequences.”

In addition to Marselis and Hubacek, the research team included Kuishang Feng and Jose Daniel Teodoro, also with the UMD Department of Geographical Sciences; and Yu Liu from the Institute of Policy and Management at the Chinese Academy of Sciences. 

COLLEGE PARK, Md.-- Malaria kills nearly half a million people every year, according to the World Health Organization (WHO). In some of the hardest-hit areas in sub-Saharan Africa, the mosquitoes that carry the malaria parasite have become resistant to traditional chemical insecticides, complicating efforts to fight the disease.

A new study from researchers at the University of Maryland and colleagues from Burkina Faso, China and Australia suggests that a mosquito-killing fungus genetically engineered to produce spider and scorpion toxins could serve as a highly effective biological control mechanism to fight malaria-carrying mosquitoes. The fungus is specific to mosquitoes and does not pose a risk to humans. Further, the study results, which are published in the June 13 edition of Scientific Reports, suggest that the fungus is also safe for honey bees and other insects. 

“In this paper, we report that our most potent fungal strains, engineered to express multiple toxins, are able to kill mosquitoes with a single spore,” said Brian Lovett, a graduate student in UMD's Department of Entomology and a co-author of the paper. “We also report that our transgenic fungi stop mosquitoes from blood feeding. Together, this means that our fungal strains are capable of preventing transmission of disease by more than 90 percent of mosquitoes after just five days.”

The researchers used the fungus Metarhizium pingshaense, which is a natural killer of mosquitoes. The fungus was originally isolated from a mosquito and previous evidence suggests that the fungus is specific to disease-carrying mosquito species, including Anopheles gambiae and Aedes aegypti. When spores of the funguscome into contact with a mosquito’s body, the spores germinate and penetrate the insect’s exoskeleton, eventually killing the insect host from the inside out.

On its own, however, the fungus requires fairly high doses of spores and a large amount of time to have lethal effects. To boost the fungus’ deadly power, the researchers engineered the fungus with several genes that express neurotoxins from spider and scorpion venom—both alone and in combination with other toxins. The toxins act by blocking the calcium, potassium and/or sodium channels required for the transmission of nerve impulses.

The researchers then tested the engineered fungal strains on wild-caught, insecticide-resistant mosquitoes in Burkina Faso. Each engineered strain killed mosquitoes more quickly and efficiently than the unaltered fungus. But the most effective strain used a combination of two toxins, one derived from the North African desert scorpion Androctonus australis and another derived from the Australian Blue Mountains funnel-web spider Hadronyche versuta. The scorpion toxin blocks sodium channels, while the spider toxin blocks both potassium and calcium channels. Both of these toxins have already been approved by the U.S. Environmental Protection Agency for insecticidal use.

“The WHO has identified insecticide resistance as the major threat to effective mosquito control, which is relevant not only to malaria but to a number of mosquito-borne diseases such as dengue, yellow fever, viral encephalitis and filariasis,” said Raymond St. Leger, a distinguished university professor in the UMD Department of Entomology and senior author of the study. “Unlike chemical insecticides that target only sodium channels, many spider and scorpion toxins hit the nervous system’s calcium and potassium ion channels, so insects have no pre-existing resistance.”

When Lovett, St. Leger and their colleagues inserted the toxin genes into the Metarhizium fungus, they included an additional failsafe: a highly specific promoter sequence, or genetic “switch,” which ensures that the toxin genes can only be activated in the blood of insects. As a result, the fungus will not release the toxin into the environment.

To further ensure the safety of non-target insect species, the researchers also tested the engineered fungal strains on honey bees. Working in Burkina Faso, the team deliberately infected local bees using both passive methods (exposing the bees to spore-coated fabric) and direct methods (spraying the bees with spores suspended in liquid). After two weeks, no bees had died as a result of the toxin-boosted fungus.

“The toxins we’re using are potent, but totally specific to insects. They are only expressed by the fungus when in an insect. Additionally, the fungus does nothing at all to bees and other beneficial species,” St. Leger said. “So we have several different layers of biosecurity at work.”

Encouraged by the results of the current study, the researchers plan to expand their on-the-ground testing regimen in Burkina Faso. Currently, the team is testing the spores on mosquitoes contained in a custom-built enclosure that resembles a greenhouse, with walls made of netting instead of glass. The researchers are also testing the fungus on insect species that are closely related to mosquitoes, such as midges and gnats, to ensure that the fungus is completely safe for non-target insects. Eventually, the team hopes to deploy the spores in the field, on wild mosquito populations.

“This is our first in-depth study of the effects toxin-expressing fungi have on mosquitoes, beyond their ability to kill faster. This is also our broadest characterization of our arsenal of insect-killing spider and scorpion toxins,” Lovett said. “Our results directly extend our understanding of how these technologies may be used in the field against mosquito pests.”

Image: A dead female Anopheles gambiae mosquito covered in the mosquito-killing fungus Metarhizium pingshaense, which has been engineered to produce spider and scorpion toxins. The fungus is also engineered to express a green fluorescent protein for easy identification of the toxin-producing fungal structures. Image credit: Brian Lovett.

COLLEGE PARK, Md. – On June 12, at the Goddard Space Flight Center in Greenbelt, Maryland, NASA posthumously awarded the Exceptional Public Service Medal to University of Maryland Distinguished University Professor Michael F. A'Hearn, one of the world's leading cometary scientists. The NASA Medal is for “fundamental work on comets and small bodies of the solar system, leadership in space missions, and ensuring public access to data from NASA missions and related projects.”

A'Hearn, who died on May 29 at his home in University Park, Maryland at the age of 76, was most widely known as the principal investigator (PI) of the NASA Deep Impact mission. On July 4, 2005, the spacecraft released a washing-machine-sized probe that collided spectacularly with comet Tempel 1, while the main spacecraft observed the results. The powerful impact gave scientists their first-ever view of pristine material inside a comet and garnered massive public attention for planetary science, solar system exploration, NASA and the University of Maryland.

The impact was also observed by NASA and other space telescopes and from Earth by many professional groundbased telescopes and thousands of amateur astronomers. The event set a then NASA record for webpage hits (more than 1 million) and drew front-page news coverage by broadcast, print and web media outlets around the world.

“Mike A’Hearn devoted his life to exploration, and his work has transformed our understanding of what comets are made of and how they interact within our corner of the universe,” said Jim Green, director of NASA’s Planetary Science Division.  “This is a great loss for the small bodies community and for me personally.”

After Deep Impact’s original mission ended, A'Hearn and his science team convinced NASA to use the surviving primary spacecraft for continued cometary studies. With A'Hearn as PI, the project embarked on an extended mission, designated EPOXI, with dual purposes-- studying extrasolar planets and comet Hartley 2. On the way to Hartley 2, the Deep Impact spacecraft flew between the Earth and the Moon. Its instruments were able to confirm the surprising presence of water on the Moon’s surface. The Deep Impact spacecraft later imaged two other comets-- C/2009 P1 Garradd (in 2012), which had a surprisingly high carbon monoxide content, and C/2012 S1 ISON (in 2013), a comet that disintegrated as it grazed past the Sun.  The images and findings of these later missions further advanced comet science and attracted more media and public attention.  

When NASA lost contact with the Deep Impact spacecraft in September 2013, A’Hearn said: “Deep Impact has been a principal focus of my astronomy work for more than a decade and I’m saddened by its functional loss. But, I’m very proud of the many contributions to our evolving understanding of comets that it has made possible.”

Illuminating the Primordial Dust 
Distinguished University Professor Michael A’Hearn’s many scientific contributions started well before and continued well beyond Deep Impact. During his more than 50 years at UMD, he studied comets using ground-based observatories, space telescopes such as the Hubble Space Telescope, and Deep Impact and other spacecraft. 

He looked at comets across the range of light (electromagnetic radiation) wavelengths from extreme ultraviolet radiation to visible light to radio waves. In particular, in the 1970’s he pioneered the study of comets in the ultraviolet, using the International Ultraviolet Explorer space telescope, coordinated the world’s ground-based observations of comet Halley in the 80’s, and in the 90’s compiled the most comprehensive set of compositional data of comets to date. 

A’Hearn’s post-Deep Impact work included being co-investigator on the Stardust-NExT mission to re-visit comet Tempel 1, which documented changes on the comet’s surface since Deep Impact, and a co-investigator on two instrument teams (the OSIRIS camera and the NASA Alice ultraviolet spectrograph), on the European Space Agency’s Rosetta mission, which co-orbited and landed on comet Churyumov–Gerasimenko. 

In addition to being a pillar of cometary science, another major contribution to planetary science was A'Hearn’s nearly three decades as principal investigator for the Small Bodies Node, which is the part of NASA's Planetary Data System that specializes in the archiving, cataloging, and distributing scientific data sets relevant to asteroids, comets and interplanetary dust. A founder and advocate for the Planetary Data System, A’Hearn championed its mission to preserve data of planets and make it publically accessible for use by future generations as they seek answers to questions that current researchers don’t even know to ask. Under his leadership, the Small Bodies Node developed from a two-person group to a strong, UMD-based, organization of 18 scientists and programmers.

Together with colleagues, many of whom he had mentored, A’Hearn used observational and exploratory tools, computer models (numerical simulations), and experiments (biggest was the Tempel 1 impact) to help us better understand comet chemistry and comet components (body, or nuclei, and surrounding gas and dust called the coma).  This work was done with the goal of gaining new insights into how the dense disc of gas and dust that had rotated around our newly formed Sun, formed into our  solar system’s planets, comets and asteroids, and thus, ultimately, into us.

“Everything about Mike was genuine-- his love of comets and the secrets they hold to our origin and his concern for individuals,” said University of Maryland Professor Jessica M. Sunshine, director of the UMD Small Bodies Group. “Mike inspired thousands of UMD undergrads to appreciate science, formally and informally guided generations of young cometary scientists all over the world and he advocated for future solar system exploration, open and long-term access to planetary data, and the protection of our planet from the hazards of cometary and asteroidal impacts.”  

Defending Planet Earth 
A’Hearn was an avid sailor who noted in one NASA biography that his second choice of profession after astronomy would have been ship’s captain.  And, like a good captain, part of his work involved protecting Earth and the living things it carries by helping in the detection of comets and asteroids orbiting in “uncharted waters” of our solar system that pose potential impact hazards to Earth and determining the best methods to prevent or mitigate such impacts.

He was vice-chair of a 2010 National Academy of Sciences/National Research Council report entitled “Defending Planet Earth: Near-Earth-Object Surveys and Hazard Mitigation Strategies (2010) Chapter: 2 Risk Analysis.” He also chaired the mitigation sub-panel that wrote the section of the report devoted to protecting our planet from dangerous “near-Earth objects” and to mitigating the damage of unavoidable impacts.  A brief interview,  A'Hearn: Protecting Earth: Four Recommendations, can be seen here.

A Deep and Lasting Impact on Comet Science and Colleagues
A'Hearn was named a Distinguished University Professor in 2000. This formal UMD title denotes University of Maryland's academic honor of highest distinction and is awarded to a limited number of UMD's most accomplished professors. Awardees are established scholars, held in the highest esteem by professional colleagues nationally and internationally, whose contributions have had a significant influence on their discipline and perhaps beyond. 

Other recognitions of his work include an Exceptional Public Service Medal from NASA and the Gerard P. Kuiper Prize from American Astronomical Society Division for Planetary Sciences. The NASA Medal was approved shortly before his death in recognition of his “fundamental work on comets and small bodies of the solar system, leadership in space missions, and ensuring public access to data from NASA missions and related projects.”  The Kuiper Prize “recognizes and honors outstanding contributors to planetary science.”

A’Hearn’s tremendous impacts on his field and university were personal as well as professional. Colleagues universally say he was a great and thoughtful friend as well as a terrific teacher and mentor for younger scientists, many of whom now will continue his legacy by further advancing the understanding of comets and asteroids and the early history of our solar system.

"Mike was a wonderful friend, mentor, and colleague to so many in our astronomy department and everywhere,” said UMD Astronomy Department Chair Stuart Vogel. “He was the founder of the department's Small Bodies Group and one of the most respected and admired planetary scientists in the world. He will be deeply missed."

In 2011 A’Hearn became a professor emeritus, but, even in “retirement” he continued to produce important work and to mentor younger scientists.  He authored a review article, Comets: Looking Ahead that was published the day of his death. He is a coauthor of at least one other forthcoming paper. 

“Dr. Mike A’Hearn was one-of-a-kind in a group of unique individuals – the hand full of planetary scientists who have led a mission of exploration through our solar system,” said Lindley N. Johnson, NASA’s planetary defense officer and program executive for Deep Impact/EPOXI. “Mike was a joy to work with. Not only was he a treasured advisor to so many graduate students, he was a valued mentor to us all.  I’d like to now think of him as having grabbed a comet by its vibrant tail – and forever riding it around the solar system.”

Born in Wilmington, Delaware in 1940, A’Hearn grew up in Boston, graduated from Boston College High School and from Boston College (’62) and received his Ph.D. from the University of Wisconsin (’66), studying polarization of the atmosphere of Venus.

Michael A’Hearn passed away at his home on May 29, 2017. He is survived by his wife Maxine, sons Brian J. A’Hearn (Zlata) of Oxford, UK, Kevin P. A’Hearn (Kanlayane) of Vienna, VA, and Patrick N. A’Hearn of Seattle, WA; and grandchildren Sean, Brendan, Marie, Eliane, and Gabriel.