Chemical ecologist Yuko Ishida of Toyama, Japan, a former UC Davis post-doctoral researcher who shared the same lab--and the same bench--in Briggs Hall that Duffey did, is the lead co-author of a cover story recently published in the Proceedings of the National Academy of Sciences (PNAS) about an invasive species of millipede that secrets hydrogen cyanide as a defensive mechanism. (See research paper)
Ishida and Duffey never met but they shared a love of science and chemical ecology, in addition to the same lab.
At the time of his death, Duffey was a professor and vice chair of the UC Davis Department of Entomology. When chemical ecologist/professor Walter Leal joined the UC Davis Department of Entomology faculty in 2000, he occupied the former labs of professors Duffey and Susumu Maeda (1950-1998) and memoralized their lives and work by naming his lab the “Honorary Maeda-Duffey lab.”
Ishida worked in the Honorary Maeda-Duffey lab from May 2001 to November 2007 at UC Davis.
“Yuko loves to tackle challenging problems and he is well prepared to solve them,” said Leal, former chair of the UC Davis Department of Entomology and now with the UC Davis Department of Molecular and Cellular Biology.
Ishida also photographed the millipede, found in southern Japan, for the PNAS cover.
The four scientists all work at the Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, and are affiliated with the Asano Active Enzyme Molecule Project, Exploratory Research for Advanced Technology, Japan Science and Technology Agency, Toyama.
“To discover more efficient and stable HNLs, we focused on the invasive cyanogenic millipede as a bioresource,” the scientists wrote. “The HNL identified from the millipede showed not only the highest specific activity toward benzaldehyde among known HNLs, including the almond HNL in industrial use, along with wide temperature and pH stabilities, but also high enantioselectivity in the synthesis of various cyanohydrins. These properties make it suitable as an industrial biocatalyst. Arthropods are likely to be valuable sources of potential biocatalysts for the next generation of industrial biotechnology.”
“There followed several papers on the biochemistry of HCN production and the production of other defensive compounds in these interesting animals,” they wrote. “After arriving at UC Davis, Sean began a long series of brilliant studies on the chemical mechanisms used by plants to fend off attack by insects and various pathogens. This work centered on resistance in tomatoes, and over the years he collaborated with numerous students and colleagues. Studies analyzed the role of numerous chemicals produced by plants including tomatine, proteinase inhibitors, and various plant oxidative enzymes. Recent studies had included analyses of induced defenses and the interactions of chemicals with the biological agents such as parasitoids and baculoviruses used in various IPM and biological control programs.”
“A constant theme and frequently emphasized message in Sean's work was the fact that chemical-biological interactions were rarely simple and straightforward,” they wrote. “He stressed that in order to understand plant-insect interactions, for example, it was necessary to understand the interactions among plant chemicals, the overall characteristics of the insect's diet, the physiological state of the insect, and the modifiable characteristics of plant and insect. Chemical and biological context and chemical mixture were seen as critical determinants of biological activity; a simple view that natural products functioned merely as "toxins" or isolated defensive factors was often misleading.”
Carey, Dingle and Ullman praised Duffey's "truly interdisciplinary research that included several joint projects with members of the Entomology Department and also with colleagues in the departments of Nematology Ecology and Plant Pathology. We all experienced Sean insisting over and over that interactions are not simple and that one must understand the chemistry, the physiology, and the ecology to really understand interactions between plants, insects, and their pathogens. Sean's legacy is an outstanding record of how to go about studying plant-insect interactions, not just the gathering of data on interactions that occur.”
The legacy continues...
Especially since the United States is busily restoring diplomatic relations with Cuba.
Think entomology. Think ICE. Think ICE'ing on the cake. Think ICE'ing on an entomological cake.
When the 2016 International Congress of Entomology (ICE 2016), co-chaired by a UC Davis chemical ecologist Walter Leal takes place next year in Orlando, Fla., it truly will follow the theme, “Entomology without Borders.”
One of Cuba's leading entomologists will deliver an invitational lecture on the mosquito that transmits dengue, announced Leal, professor of biochemistry and chemical ecology at the UC Davis Department of Molecular and Cellular Biology, and former chair of the UC Davis Department of Entomology
Juan Andrés Bisset, head of the Vector Control Department at the Pedro Kouri Institute of Tropical Medicine and an advisor to the Cuban Public Health Ministry, will speak on “Aedes aegypti Management Strategies for Dengue Control in Cuba.” He studied at UC Riverside with G.P. Georgiou in 1986.
“When I received my first passport as a Brazilian citizen, it was stamped ‘not valid' for Cuba,” recalled Leal. “That sparked a curiosity about that country. After I become an entomologist and a U.S. citizen, my curiosity shifted toward entomology in Cuba. Fast forward to today: The International Congress of Entomology could not justify its theme, ‘Entomology without Borders,' if we did not have at least one delegate from Cuba.”
“We are absolutely delighted to host Dr. Juan Bisset.”
Added ICE 2016 co-chair Alvin Simmons, U.S. Department of Agriculture research entomologist: “We are dedicated to providing a premier congress experience for 7,000 to 8,000 international attendees. This includes fostering an environment of scientific breadth and all-inclusiveness. So, it is quite fitting for participation from Cuba to be a part of this historical event.”
The conference, expected to be the world's largest gathering of entomologists, takes place Sept. 25-30, 2016. Bisset will speak from 4:30 to 5:30 p. m. Tuesday, Sept. 25. Many mosquito researchers, including those from the University of California, are expected to attend.
In an email to Bisset, Leal called attention to a recent editorial in Science magazine “Science in U.S. Cuba relations” (May 15, 2015).
“ICE 2016 will be a historic global event, as this conference will return to the United States after a 40-year hiatus,” Leal told him. “We are expecting the participation of 7,000-8,000 delegates, including Dr. Peter Agre (Nobel Laureate, 2003 - a strong advocate for science diplomacy, particularly Cuba-US relations) and Dr. Jules Hoffmann (Nobel Laureate, 2011), Dr. John Hildebrand, and many other distinguished scholars."
Bisset is heavily involved in the control of vectorborne diseases, including diseases transmitted by several mosquitoes, such as Culex quinquefasciatus, Anopheles albimanus, and Aedes aegypti. He focuses his main research on ecology, dynamic population of insects, insecticide resistance, and resistance mechanisms.
The recipient of some 18 international and national awards, Bisset has been published his research in 106 scientific papers. Since 1990, he has participated in more than 45 technical activities as an adviser on malaria and dengue vector control in Latin American countries, and is a frequent lecturer in Cuba and other countries.
ICE is held once every four years in different countries around the world. Next year it will be held simultaneously with the annual meetings of the Entomological Society of America, the Entomological Society of Canada, and other organizations.
“Each Congress provides a forum for scientists, researchers, academia, technicians, government, and industry representatives to discuss the latest research and innovations in the many diverse fields of entomology, to share expertise in their specific fields of interest, and to present their research and products,” said Richard Levine, ESA's communications program manager, in a news release. “The week-long meetings allow participants to meet others from around the world with similar focus areas and to form important networks to collaborate and share knowledge, with an overarching goal of supporting and protecting the world's population through better science."
For more information about ICE 2016, access http://ice2016orlando.org.
Well, ICE is red hot.
The International Congress of Entomology (ICE) is gearing up for its 2016 conference, "Entomology without Borders," to take place Sept. 25-30, 2016 in Orlando, Fla., and the line-up of speakers should make all entomologists--and others interested in insect science--mark their calendars.
With a red-hot pen.
The ICE meeting will be co-located with the annual meetings of the Entomological Society of America (ESA) and the Entomological Society of Canada, along with events hosted by the entomological societies of China, Brazil, Australia, and others.
First of all, the ICE co-chairs, chemical ecologist Walter Leal of UC Davis and vegetable research entomologist Alvin Simmons of USDA/ARS, managed to book not one, but two Nobel Laureautes: Peter Agre (2003 Nobel Prize in Chemistry) and Jules Hoffmann (2011 Nobel Prize in Physiology or Medicine).
Then the next announcement. Last weekend at the ESA meeting in Portland, Ore., Leal revealed the list of ICE plenary speakers, selected from 77 nominated worldwide.
Carey, a distinguished professor of entomology with the UC Davis Department of Entomology and Nematology, is considered the world's foremost authority on arthropod demography. Page, provost of Arizona State University and emeritus professor and former chair of the UC Davis Department of Entomology, is considered the most influential honey bee biologist of the past 30 years.
“We are delighted to have the first Hispanic woman (Latina) to give a plenary lecture at ICE; likewise, the first kiwi (New Zealander), as well as the first native African to have the opportunity to highlight their work in this venue,” said Leal, professor in the UC Davis Department of Molecular and Cellular Biology.
The list of plenary speakers:
- Carolina Barilla-Mury, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Guatemala & USA, who will speak on medical entomology immunity
- Jacqueline Beggs, University of Auckland, New Zealand. Topic: biodiversity and biosecurity
- James R. Carey, University of California, Davis. Topic: insect biodemography
- Fred Gould, North Carolina State University. Topic: GMOs: crop and health protection
- Robert E. Page, Arizona State University. Topic: bee biology: Spirit of the Hive” (title of his latest book)
- José Roberto Postali Parra, ESALQ, University of Sao Paulo, Brazil. Topic: biological control.
- John A. Pickett, Rothamsted Research, UK. Topic: insect-plant interactions
- Baldwyn Torto, Centre of Insect Physiology & Ecology, based in Nairobi, Kenya. Topic: colony collapse disorder and pollination.
Capsule information on the UC Davis-affiliated entomologists:
James R. Carey has authored more than 250 scientific articles, including landmark papers in Science that shaped the way scientists think about lifespan limits and actuarial aging, and two articles in the Annual Review series that provide new syntheses on insect biodemography (2003, Annual Review of Entomology) and aging in the wild (2014, Annual Review of Ecology, Evolution, and Systematics). He directed a $10 million multi-university grant for more than a decade (2003-2013).
Carey is the author of three books, including Applied Demography for Biologists with Special Emphasis on Insects (Oxford University Press), the go-to source for all entomologists studying demography. Highly honored for his work, Carey received the 2014 C. W. Woodworth Award, the highest honor bestowed by the Pacific Branch of the Entomological Society of America (ESA), and the 2014 UC Davis Academic Senate Distinguished Teaching Award for innovative and creative teaching.
Carey chaired the University of California Systemwide Committee on Research Policy—one of the most important and prestigious committees in the UC system and served on the systemwide UC Academic Council. In addition, he serves as the associate editor of three journals: Genus, Aging Cell, and Demographic Research. In addition, he is the first entomologist to have a mathematical discovery named after him by demographers—The Carey Equality—which set the theoretical and analytical foundation for a new approach to understanding wild populations.
He is a fellow of four professional organizations: ESA, the Gerontological Society of America, the California Academy of Sciences and the American Association for the Advancement of Science.
Carey has presented more than 250 seminars in venues all over the world, from Stanford, Harvard, Moscow, Beijing to Athens, London, Adelaide and Okinawa. In addition, Carey is considered a worldwide authority on the demography and invasion biology of tephritid fruit flies, particularly the Mediterranean fruit fly; and a preeminent authority on biodemographics of human aging and lifespan. He is also a pioneering force advocating the educational use of digital video technology, work that he is sharing throughout much of the state, nation and the world.
Carey received his bachelor's degree (animal ecology, 1973) and master's degree (entomology, 1975) from Iowa State University, and his doctorate in entomology from UC Berkeley in 1980.
Robert E. Page Jr.
Page has published more than 200 reviewed publications, three edited books and two authored books. His latest book is "Spirit of the Hive." His lab pioneered the use of modern techniques to study the genetic bases to the evolution of social behavior in honey bees and other social insects.
Page was the first to employ molecular markers to study polyandry and patterns of sperm use in honey bees. He provided the first quantitative demonstration of low genetic relatedness in a highly eusocial species.
Among his other achievements involving honey bee research:
- Page and his students and colleagues isolated, characterized and validated the complementary sex determination gene of the honey bee; perhaps the most important paper yet published about the genetics of Hymenoptera.
- He and his students constructed the first genetic map of any social insect, demonstrating that the honey bee has the highest recombination rate of any eukaryotic organism mapped to date.
In addition, Page was personally involved in genome mappings of bumble bees, parasitic wasps and two species of ants. His most recent work focuses on the genetic bases to individuality in honey bees.
Page also built two modern apicultural labs (in Ohio and Arizona), major legacies that are centers of honey bee research and training. He has trained many hundreds of beekeepers, and continues to teach beekeeping even as provost of the largest public university in the United States. He is also the Foundation Chair of Life Sciences.
An internationally recognized scholar, Page is an elected foreign member of the Brazilian Academy of Science, a fellow of the American Association for the Advancement of Science, and an elected member of the American Academy of Arts and Sciences and the oldest scientific academy of science, the Germany Academy of Sciences Leopoldina. He was elected to Leopoldina, founded in 1652, for his pioneering research in behavioral genetics of honey bees.
It promises to be an informative, educational and entertaining meeting in Orlando!
However, not everyone wants to use DEET, a synthetic insect repellent. There's that smell, for one thing. "Properties that people do not like in addition to the smell is that DEET is a solvent for plastic," says chemical ecoloigst Walter Leal of the University of California, Davis. "So, one gets eyeglass frames and watchbands dissolved by DEET."
There's also "the misconception that everything synthetic is bad."
So what is it with DEET that repels mosquitoes? What odorant receptor is involved? Mosquitoes, as we know, detect smells with their antennae.
The Leal lab today (Oct. 27) published research in the Proceedings of the National Academy of Sciences (PNAS) that pinpoints the exact odorant receptor that repels them. They also identified a plant defensive compound that might mimic DEET, a discovery that could pave the way for better and more affordable insect repellents.
For more than six decades, DEET has been known as the gold standard of insect repellents. More than 200 million people worldwide use the chemical insect repellent, developed by scientists at the U.S. Department of Agriculture and patented by the U.S. Army in 1946.
So when Leal and his team--project scientist Pingxi Xu, postdoctoral scholar Young-Moo Choo, and agricultural and environmental chemistry graduate student Alyssa De La Rosa-- published their groundbreaking research, “Mosquito Odorant Receptor for DEET and Methyl Jasmonate,” they drew global attention.
In their research, they examined the receptors of the southern house mosquito, Culex quinquefasciatus, which transmits such diseases as West Nile virus.
The researchers set out to investigate two hypotheses regarding DEET's mode of action: activation of ionotropic receptor IR40a vs. odorant receptor(s). “Ionotropic receptor is another family of olfactory receptors, which seem to be the ancestral version when insects were aquatic,” Leal said. “So, the ionotropic receptors normally detect acid, bases, and other water soluble compounds.”
“Vector-borne diseases are major health problems for travelers and populations living in endemic regions,” said Leal. “Among the most notorious vectors are mosquitoes that unwittingly transmit the protozoan parasites causing malaria and viruses that cause infections, such as dengue, yellow fever, chikungunya, and encephalitis.”
Leal said that diseases transmitted by mosquitoes destroy more lives annually “than war, terrorism, gun violence, and other human maladies combined. Every year, malaria decimates countless lives – imagine a city of San Francisco perishing to malaria year after year. The suffering and economic consequences in endemic areas are beyond imagination for those living in malaria-free countries. Both natives and visitors to endemic areas want to keep these ‘infected needles' at bay. In the absence of vaccines for malaria, dengue, and encephalitis, one of the most ancient and effective prophylactic measures against mosquito-borne diseases is the use of DEET.”
Dan Strickman of the Bill and Melinda Gates Foundation, not involved in the study, praised the work. “We are at a very exciting time for research on insect repellents,” said Strickman, senior program officer of the Global Health Program's Vector Control. “ For decades, the field concentrated on screening compounds for activity, with little or no understanding of how chemicals interacted with mosquitoes to discourage biting. Use of modern techniques that combine molecular biology, biochemistry, and physiology has generated evidence on how mosquitoes perceive odors.”
Said zoologist Paul Weldon of the Smithsonian's Conservation Biologist Institute, also not involved in the study: “Since DEET is strictly synthetic and not a natural product, it has been challenging to understand the adaptive nature of the response it elicits. It is not as if the compound emanates from, say, spider webs or fishy water, where avoidance by mosquitoes would make sense. Xu et al. have solved the mystery of where the DEET response comes from: it is in response to plant chemical defenses.”
“This, by the way, also explains why the DEET response is widespread, occurring in many arthropods, including those that are not ectoparasitic -- like cockroaches,” Weldon said. The repellence of other arthropods by DEET may have tipped off some of those investigating the DEET response, but I'm not sure that it did. The focus of research on DEET seems to have been with the organisms in which it just so happened to be discovered -- mosquitoes. The Xu et al. study suggests that there is a much broader array of DEET-sensitive organisms than previously suspected. No doubt, this finding will assist further investigations of it.”
Professor John Pickett, Rothamsted Research, UK, also not involved in the study, called the link between the plant compound and synthetic insect repellent, DEET as a “surprising evolutionary link.”
Pickett, the Michael Elliott Distinguished Research Fellow and Scientific Leader of Chemical Ecology at Rothamsted Research and a foreign associate of the National Academy of Sciences, said: “Not only does this work demonstrate that a mosquito response to the gold standard repellent DEET, as well as the more recently developed repellents, is mediated by a specific odorant receptor (OR136 for the southern house mosquito Culex quinquefasciatus) but that the receptor responds specifically also to methyl jasmonate, involved in plant hormone-based defense against insects, which suggests a surprising evolutionary link between these types of insect interactions.”
The UC Davis researchers pointed out that “insect repellents have been used since ancient times as prophylactic agents against diseases transmitted by mosquitoes and other arthropods, including malaria, dengue fever, and encephalitis. They were developed from plant-based smoke or extracts (essential oils) into formulations with a single active ingredient.”
Progress toward development of better and more affordable repellents has been slow, they said, because scientists weren't sure which odorant receptor was involved. Now they are.
Mosquito researcher Anthony "Anton" Cornel, associate professor with the UC Davis Department of Entomology and Nematology, and based at the UC Kearney Agricultural Research and Extension Center, Parlier, provided the mosquitoes that allowed the Leal lab to duplicate his mosquito colony at UC Davis.
Look for more exciting research to come!
When chemical ecologist Walter Leal, professor of entomology at the University of California, Davis, was elected to the prestigious Brazilian Academy of Sciences, his lab members donned matching t-shirts--t-shirts with a touch of humor and a dose of humility.
On the front: "I did the work."
On the back: "And Walter Leal got in the Academy."
It was his idea and he purchased the t-shirts.
Leal, a native of Brazil, will be honored at a ceremony on May 7 in Rio de Janeiro.
“Let me say that your election to the Brazilian Academy of Sciences is a well-deserved recognition for your accomplishments as a distinguished scientist in your field of studies, entomology, and also for the very important role you have been playing in promoting cooperation among Brazilian and U.S .universities and, through those arrangements, fostering scientific development in our country,” said Ambassador Eduardo Prisco of the Brazilian Consulate in San Francisco.
Leal, a native of Brazil, is a liaison with UC Davis and the Brazil government’s Scientific Mobility Program, launched to exchange graduate and undergraduate students.
The U.S. currently hosts the largest number of students participating in the Brazil government’s Scientific Mobility Program, according to the Institute of International Education, and UC Davis leads the nation, hosting more than 30 Brazilian undergraduate scholarship students. Leal is also involved in the Brazilian/UC Davis student exchange with the Federal Agency for Support and Evaluation of Graduate Education (CAPES) and the National Council for Scientific and Technological Development (CNPq) grants for research related to Brazil.
A pioneer in the field of insect communication and on the cutting edge of research, Leal employs innovative approaches to insect olfaction problems. His work examines how insects detect smells, communicate with their species, detect host and non-host plants, and detect prey. Leal has designed and synthesized complex pheromones from many insects, including scarab beetles, true bugs, longhorn beetles and the citrus leafminer. He and his lab discovered the secret mode of the insect repellent DEET.
Leal, educated in Brazil and Japan, joined the UC Davis Department of Entomology in 2000. He holds a doctorate in applied biochemistry from Tsukuba University, Japan, and also earned degrees in chemical engineering and agricultural chemistry.
You'll be hearing much more of Walter Leal. Active in national and international entomological circles, the UC Davis professor is serving as co-chair of the International Congress of Entomology (ICE) conference, to be hosted by the Entomological Society of America (ESA) Sept. 25-30, 2016 in Orlando, Florida.
His honors and awards are many. He is a Fellow of the ESA, the Royal Entomological Society, and the American Association for the Advancement of Science. He served as president of the International Society of Chemical Ecology (ISCE). Among his awards: the ISCE Silver Medal, and awards from ESA and scientific societies in Japan and Brazil.
Caption (Top Photo):
The Walter Leal lab wore humorous t-shirts to announce his selection to the Brazilian Academy of Sciences. Four countries are represented in this lab photo. The four in front are (from left) Junior Specialist Hang Gao, United States; Professor Fen Zhu, Huazhong Agricultural University, China; Professor Leal, a native of Brazil; and Graduate Student Alyssa De La Rosa (Agricultural and Environmental Chemistry Graduate Group). Circling them in back are (from left) Postdoctoral Fellow Cherre Sade, Brazil; Postdoctoral Fellow Young-Moo Choo, Korea; Project Scientist Pingxi Xu, China; Graduate Student Kevin Cloonan (entomology major), Professor Carlos Ueira Vieira, Federal University of Uberlandia, Brazil; Graduate Student Yinliang Wang, Northeast Normal University, China; and Graduate Student Washington Carvalho, Federal University of Uberlandia.