So says noted chemical ecologist Walter Leal, newly selected recipient of the 2020 Distinguished Teaching Award for Undergraduate Teaching from the UC Davis Academic Senate.
The award recognizes outstanding teaching and dedication to student success. Leal will be honored with other Academic Senate and Academic Federation award recipients at a ceremony in the spring.
"When I started teaching chemistry in high school--while I was a sophomore in college--students were only one to two years older than me," said Leal, a distinguished professor in the UC Davis Department of Molecular and Cellular Biology and former chair of the UC Davis Department of Entomology (now Department of Entomology and Nematology). "Now they are younger than my sons and daughter! My goal remains the same--not only to excite students about the content of my lectures, be it high school chemistry, insect physiology, or biochemistry, but also to trigger their curiosity.
"I don't teach because I have to; I teach because it is a joy to light the way and to spark the fire of knowledge," Leal said. "Teaching is, and out to be, the raison d'etre of a university professor. It is really an honor to receive the Academic Senate Distinguished Teaching Award. Many thanks to my peers, all students, and teaching assistants, particularly Fran Keller and Silvia Hilt who teamed up for insect physiology and biochemistry, respectively, for more than three years."
Nominator J. Clark Lagarias, distinguished professor of biochemistry in the Department of Molecular and Cellular Biology described Leal as an exemplary, innovative and highly respected teacher. “Walter excels in developing new courses, programs and teaching methods. He is a trendsetter whose passion, innovation, dedication and outstanding contributions to teaching inspire us all.”
Distinguished professor James R. Carey of the UC Davis Department of Entomology and Nematology--and the recipient of four teaching awards including the Academic Senate's top teaching award--praised Leal's innovative and dedicated teaching.
"I consider Professor Leal as an exceptional instructor," Carey wrote in the nomination packet. "His exceptionalism is derived from his dedication to student learning, his innovation in content delivery, his engagement with students (including his always-clever touches of humor), and his ability to both motivate them and incentivize their investment in studies. All of these efforts rest on the deep foundation of the disciplinary authority that he brings to the classroom as an eminent basic and applied biochemist, a stature that his students clearly recognize...Walter is a natural teacher who not only speaks with a voice of great authority in the classroom, but with the voice of a person who cares deeply about student learning."
Stanford graduate student Garrison Buss, who studied with Leal ("my research mentor at UC Davis"), said the professor "consistently encouraged active learning at a high level through a variety of modalies. Among these, the most novel and beneficial included having students solve equations by writing them out on an iPad and projecting what they wrote in real time—similar to having a portable overhead projector that any student in the lecture hall could use. This way, the whole class could see and provide feedback by critiquing the problem and solutions together with Dr. Leal. The lecture material itself was also innovative. Dr. Leal would show videos of real life experiments and interviews that he had made with prominent scientists who were subject matter experts in the topic that we were discussing."
"The lecture material itself was also innovative," Buss related. "Dr. Leal would show videos of real life experiments and interviews that he had made with prominent scientists who were subject matter experts in the topic that we were discussing. As an instructor, he challenged the way that I understood my academic performance and through his extra effort showed me that I could achieve much more than I had previously believed. As a mentor, he gave me opportunities and responsibilities that were out of reach for many of my fellow researchers."
A native of Brazil, Leal was educated in Brazil, Japan and the United States in the fields of chemical ecology, biochemistry, insect physiology and olfaction. He joined the UC Davis faculty in 2000, and chaired the Department of Entomology from 2006 to 2008.
The veteran teacher, a member of the Department of Molecular and Cellular Biology faculty since 2013, has taught insect physiology for 13 years and biochemistry for six years. In his classrooms, he employs the strategic use of digital technology, which has led to such unsolicited comments on the “Rate My Professors” website as “best professor at UC Davis.” His tools include Camtasia, PowerPoints, podcasts, e-reviews and Skype for ease of learning and knowledge retention. He generates animated e-reviews by recording a narrative summary of each of his lectures with Camtasia software. In place of a verbal narrative, his students watch videos--featuring animations and illustrations--to review major concepts.
The e-reviews can be time-consuming to produce but he considers them—and rightfully so—valuable for increased student engagement and comprehension. With Skype, Leal also brings noted guests into his classroom: researchers, textbook authors and colleagues who have made landmark discoveries in the field.
Known as a leader and inventor as well as a noted scientist and teacher, Leal co-chaired the 2016 International Congress of Entomology and also served as president of the International Society of Chemical Ecology. He is a fellow of the 7000-member Entomological Society of America, which selected him to deliver the Founders' Memorial Lecture at its recent meeting in St. Louis, Mo. His topic chronicled the life of Tom Eisner, the father of chemical ecology and a role model: “Tom Eisner: an Incorrigible Entomophile and Innovator Par Excellence.” Leal also is a newly selected fellow of the National Academy of Inventors, which honors and encourages academic inventions that benefit society.
Teaching, however is the raison d'etre.
"I don't teach because I have to; I teach because it is a joy to light the way and to spark the fire of knowledge."
- Walter Leal, distinguished professor, Department of Molecular and Cellular Biology and former chair of the Department of Entomology (now the Department of Entomology and Nematology
- Cristina Davis, the Warren and Leta Geidt Endowed Professor and Chair, Department of Mechanical and Aerospace Engineering
NIA honors and encourages academic inventions that benefit society. Between the two UC Davis faculty members, they hold 42 patents: Davis with 12; and Leal with 28 Japanese and 2 U.S. patents.
Davis is a world leader in trace chemical sensing, while Leal is a leading global scientist in the field of insect olfaction and communication, investigating how insects detect odors, how they detect host and nonhost plant matter, and how they communicate within their species.
Leal's research, spanning three decades, focuses on insects that carry mosquito-borne diseases as well as agricultural pests, such as the Asian citrus psyllid and the orange navelworm. He and his lab drew international attention with their discovery of the mode of action of DEET, the gold standard of insect repellents.
We remember when Leal and a group of 18 students hosted a Zika Public Awareness Symposium in 2016 on the UC Davis campus. It was an amazing symposium that drew attention to Aedes aeqytpi, which transmits the disease. Soon thereafter, Brazilian-born Leal and his colleagues in Brazil, detected the Zika virus in wild-caught Culex quinquefasciatus mosquitoes in Recife, the epicenter of the Zika epidemic.
We also remember when Leal identified the sex pheromones of the navel orangeworm (Amyelois transitella), a pest of almonds, figs, pomegranates and walnuts, the major hosts. This led to practical applications of pest management techniques in the fields.
Those are just several examples of the work he does. And still, he found time to co-chair the 2016 International Congress of Entomology meeting, "Entomology Without Borders," in Orlando, Fla., that drew the largest delegation of scientists and experts in the history of the discipline: 6682 attendees from 102 countries.
We're not sure how Leal can find the time to do all this (see news story on the UC Davis Department of Entomology and Nematology). We figure he must have a clone! Make that multiple clones!
At any rate, Leal is the second faculty member affiliated with the entomology department to be selected an NIA fellow. The other scientist: Bruce Hammock, distinguished professor, who holds a joint appointment in the Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center. Hammock is the co-founder and chief executive officer of EicOsis LLC, a Davis-based company that is developing a non-opiate drug to relieve inflammatory pain in companion animals and target chronic neuropathic pain in humans and horses.
As Hammock said: “When Walter Leal reached UC Davis (in 2000), he came with the reputation of being a 'one man army in research.' This reputation was well deserved. I know of no one at UC Davis who matches Walter in taking his remarkable fundamental advances in science and translating them to increase the safety and magnitude of world food production.”
Jordan, the second-highest-scoring NBA player scorer (5,987 points), "wasn't good enough" to make his high school varsity basketball team (at first). And the late Tom Eisner, the renowned Cornell University professor who went on to be known as "the father of chemical ecology," just "wasn't good enough" to be accepted at Cornell as an undergraduate student.
"Sorry, you didn't make it!" probably rang in their ears.
So when chemical ecologist and distinguished professor Walter Leal of the University of California, Davis, delivers the Founders' Memorial Award Lecture on Tom Eisner (1929-2011) at the Nov. 17-20 Entomological Society of America (ESA) meeting in America's Center in St. Louis, Mo., the Jordan-Eisner comparison will surface amid all of Eisner's incredible accomplishments, including his National Medal of Science award in 1994 from President Bill Clinton for his "seminal contributions in the fields of insect behavior and chemical ecology, and for his international efforts on biodiversity."
Leal will speak on "Tom Eisner--An Incorrigible Entomophile and Innovator Par Excellence" at the Founders' Breakfast meeting that begins at 7:30 a.m., Tuesday, Nov. 19. His presentation, at 8:15, promises to be inspirational, educational and entertaining. (And it's free to all ESA meeting registrants.)
ESA established the Founders' Memorial Award in 1958 to honor the memory of scientists providing outstanding contributions to entomology.
Eisner is known as an exemplary scientist, teacher and leader whose research discoveries focused on how insects use their chemical substances as friends or foes: to attract mates or to defend from foes. He discovered how "a bombardier beetle creates a chemical reaction within its body and then ejects a boiling hot chemical from its abdomen." As Joe Rominiecki, ESA communications manager, said: “Notable among them was deciphering how the bombardier beetle defends itself with an internal exothermic chemical reaction, explosively sprayed at attackers. That discovery topped a lengthy list of revelations about the complex and often surprising biochemicals insects produce, from the bitter, predator-deterring taste of the cochineal scale's brilliant red pigment to the sticky foot secretions that allow the palmetto beetle to cling so tightly to leaf surfaces.“
Leal, whose career spans three decades (see Bug Squad blog) built his career on Eisner's work. So we asked Leal to name 10 interesting facts about Tom Eisner. He obliged.
- Tom Eisner was born in Nazi Germany, moved to Spain, grew up in Uruguay, moved to the United States, and lived the rest of life here.
- In 1969 Tom delivered the Founders' Memorial Lecture to honor Robert Snodgrass. This year he is being honored by the same memorial lecture.
- Tom was an excellent musician; he owned three Steinway Grands (two remain with his daughters and the other he gave to the Cornell Music Department
- Cornell University rejected his undergraduate application in 1947.
- After being rejected by Cornell, Tom attended community college and received both his bachelor's degree and doctorate from Harvard.
- Ten years after Cornell rejected his undergraduate application, Cornell hired him as an assistant professor. Tom kept a framed copy of his rejection letter from Cornell on his office wall, all during his career.
- Tom is considered one of the founding fathers of chemical ecology but he joked that this cannot be proved "without a paternity test."
- Tom humbly said he had no good ideas, but that he "got good data to support other people's ideas."
- One of Tom's many covers of Science appeared on 4th of July (1969) to highlight the “fireworks” from bombardier beetles.
- For an unknown reason, Tom never traveled by air. He loved to drive long stretches to allow time to connect thoughts and relive experiences.
Leal, whose distinguished career includes co-chair of the 2016 International Congress of Entomology (ICE), serves as a distinguished professor in the UC Davis Department of Molecular and Cellular Biology and is a past chair of the UC Davis Department of Entomology (now the Department of Entomology and Nematology). In his research, Leal investigates the molecular basis of olfaction in insects and insect chemical communication. (See the Leal lab's work on DEET in Entomology Today.)
And another factoid: Leal is the first UC Davis scientist selected to present the Founders' Memorial Lecture. (Medical entomologist Shirley Luckhart of the University of Idaho, formerly of UC Davis, delivered the lecture in 2018.)
One other factoid: Tom Eisner, born in Berlin, was multi-lingual in German, French, Spanish and later English. Leal, born in Brazil, speaks Portuguese, Japanese and English fluently.
(Editor's Note: Listen to Walter Leal's presentation on YouTube)
The insect, a native of Asia, was first detected in the United States (Palm Beach County, Florida) in 1998, and California (San Diego County) in 2008. HLB, the bacterial disease that it transmits, was first detected in Florida in 2005, and in California (Hacienda Heights, Los Angeles County), 2012.
“The ACP has the potential to establish itself throughout California wherever citrus is grown,” according to the California Department of Food and Agriculture (CDFA).
Now an international team of scientists, led by chemical ecologist Walter Leal of the University of California, Davis, has discovered a new lure or male attractant that's more efficient and effective than the current trap surveillance system of yellow sticky traps.
“Our newly discovered lure captures an average of three times more ACP than the current trapping system, the sticky yellow traps,” said Leal, a distinguished professor in the Department of Molecular and Cell Biology and a former chair of the Department of Entomology and Nematology. “And it works in areas with low population densities. This is particularly important in California, because HLB is already established in urban areas and, therefore, trap surveillance systems are at a premium.”
The research, “Laboratory and Field Evaluation of Acetic Acid-Based Lures for Male Asian Citrus Psyllid, Diaphorina citri, is published today (Sept. 9) in Scientific Reports. It can be accessed free online at https://www.nature.com/articles/s41598-019-49469-3.
The 16-member team, which includes scientists from Brazil and Costa Rica and Benjamin Lehan of California State Polytechnic University, Pomona, wrote in their abstract: “Lures are much needed for improving ACP trapping systems for monitoring populations and surveillance. Previously, we have identified acetic acid as a putative sex pheromone and measured formic acid- and propionic acid-elicited robust electroantennographic responses. We have now thoroughly examined in indoor behavioral assays (4-way olfactometer) and field tests the feasibility of these three semiochemicals as potential lures for trapping ACP. Formic acid, acetic acid, and propionic acid at appropriate doses are male-specific attractants and suitable lures for ACP traps, but they do not act synergistically.”
“An acetic acid-based homemade lure, prepared by impregnating the attractant in a polymer, was active for a day,” they wrote. “A newly developed slow-release formulation had equal performance but lasted longer, thus leading to an important improvement in ACP trap capture at low population densities.”
“The disease has ravaged the citrus industry in China and Brazil,” said Leal, a native of Brazil. “In Brazil, about one-fourth of the citrus trees in the state of São Paulo has been eradicated since 2004 as part of an HLB control strategy. Florida has also sustained severe losses.
Now the disease threatens California's citrus growers “Of note, 1,100 findings of HLB in urban, but not in commercial orchards, suggest that the disease is already established in urban areas in California,” the scientists wrote. “Monitoring ACP populations is essential for integrated vector management and, more importantly, for surveillance. One of the challenges for abatement personnel in areas of low ACP densities is to capture the vector to determine infection status so that control strategies can be implemented before HLB is spread. Therefore, the development of trapping systems is at a premium, particularly the discovery of lures for enhancing ACP captures in areas of low populations.”
Earlier, an international team of scientists led by Leal identified the sex pheromone of the Asian citrus psyllid. Leal, a fellow of the Entomological Society of America and the Entomological Society of Brazil, announced the discovery, encompassing six years of research, at the 10th Annual Brazilian Meeting of Chemical Ecology in Sao Paulo in December 2017. (See Bug Squad blog)
Pheromones and other semiochemicals are widely used in agriculture and medical entomology. “Growers use them as lures in trapping systems for monitoring and surveillance, as well as for strategies for controlling populations, such as mating disruption and attraction-and-kill systems,” Leal noted.
In response to the ACP invasion in California, the CDFA has launched an extensive monitoring program to track the distribution of the insect and disease. They check yellow sticky traps in both residential areas and commercial citrus groves, and also test psyllids and leaf samples for the presence of the pathogen.
Survey methods for ACP include visual inspections; sweep netting, and placement of yellow sticky traps in trees in citrus nurseries, commercial citrus-producing areas and residential properties throughout the state, according to the CDFA. They also place sticky traps in California fruit packing houses, specialty markets, retail stores and airports that receive such produce from areas known to be infested with ACP.
CDFA has set up a hotline at (1-800-491-1899) for residents to report suspicious insects or disease symptoms in their citrus trees.
They manage to find us, don't they? Even when we're doing our best to try to avoid them!
It's not so well-known that mosquitoes, both male and female, frequent plants to feed on nectar for energy.
And now UC Davis chemical ecologist Walter Leal and scientists Fangfang Zen and Pingxi Xu of the Leal lab have discovered that the odorant receptors from the southern house mosquito, Culex quinquefasciatus, and the yellow fever mosquito Aedes aegypti, are sensitive to floral compounds.
The manuscript: "Odorant Receptors from Culex quinquefasciatus and Aedes aegypti Sensitive to Floral Compounds."
The team, led by Leal, a distinguished professor in the Department of Molecular and Cellular Biology and a former chair of the UC Davis Department of Entomology, cloned the genes of several odorant receptors from the mosquitoes and tested them, using egg cells of Xenopus toads. They exposed the cloned receptors to different scent chemicals.
"We are delighted to find out how mosquitoes smell plant-derived compounds and are repelled by them," Leal said. "These findings may lead to the discovery of better repellents from natural sources."
"Mosquitoes rely heavily on the olfactory system to find a host for a bloodmeal, plants for a source of energy and suitable sites for oviposition," the scientists explained in their abstract. "Here, we examined a cluster of 8 odorant receptors (ORs), which includes one OR, CquiOR1, previously identified to be sensitive to plant-derived compounds. We cloned 5 ORs from Culex quinquefasciatus and 2 ORs from Aedes aegypti, ie, CquiOR2, CquiOR4, CquiOR5, CquiOR84, CquiOR85, AaegOR14, and AaegOR15 and then deorphanized these receptors using the Xenopus oocyte recording system and a large panel of odorants. 2-Phenylethanol, phenethyl formate, and phenethyl propionate were the best ligands for CquiOR4 somewhat resembling the profile of AaegOR15, which gave the strongest responses to phenethyl propionate, phenethyl formate, and acetophenone. In contrast, the best ligands for CquiOR5 were linalool, PMD, and linalool oxide. CquiOR4 was predominantly expressed in antennae of nonblood fed female mosquitoes, with transcript levels significantly reduced after a blood meal. 2-Phenylethanol showed repellency activity comparable to that of DEET at 1%. RNAi experiments suggest that at least in part 2-phenylethanol-elicited repellency is mediated by CquiOR4 activation."
Meanwhile, Leal is gearing up for the 2019 Entomological Society of America (ESA) meeting in St. Louis, Mo., where he will deliver the Founders' Memorial Award Lecture on “Tom Eisner — An Incorrigible Entomophile and Innovator Par Excellence,” at the awards breakfast on Tuesday, Nov. 19.
ESA officials selected Leal, an ESA fellow and internationally recognized chemical ecologist, for the global honor. Leal is the first UC Davis scientist selected to present the Founders' Memorial Lecture, although medical entomologist Shirley Luckhart of the University of Idaho, formerly of UC Davis, delivered the lecture in 2018.
The 7000-member ESA is the world's largest organization serving the professional and scientific needs of entomologists and people in related disciplines. ESA, founded in 1889, is headquartered in Annapolis, Md.