Posts Tagged: Gregory Lanzaro
Anthony “Anton” Cornel knows his mosquitoes--and a few snakes, too.
When he was doing research in Brazil in September, he draped a snake around his neck and posed for the camera.
His favorite research subjects, though, are mosquitoes.
- The yellow fever mosquito, Aedes aegypti, found throughout the tropics and subtropics and a newly invasive species in central California.
- The West Nile virus mosquito, Culex quinquefasciatus, found throughout much of the world.
- The malaria mosquito, Anopheles gambiae, which wreaks worldwide havoc.
Cornel's name appeared in the news this week when the UC Davis lab of Walter Leal announced that it had found the odorant receptor that repels DEET in the southern house mosquito, Culex quinquefasciatus mosquito. Cornel provided the mosquitoes that allowed the Leal lab to duplicate his colony. Proceedings of the National Academy of Sciences (PNAS) published the work Oct. 27.
Cornel's main research keys in on the population genetics and ecology of West Nile virus vectors in the United States and population genetics and ecology of major malaria vectors in Africa.
“Anton is a great asset to our program, a wonderful colleague, and a nice team player,” said Leal, a professor in the Department of Molecular and Cellular Biology. “We benefit greatly from his generosity by sharing not only mosquito colonies, but also his encyclopedic knowledge on mosquito biology and ecology. We shared co-authorship in a number of publications, and many more are coming.”
Cornel collaborates with Leal on oviposition attraction in Culex quinquefasciatus and “we are now endeavoring to come up with effective oviposition attractive chemical lures to use in virus surveillance and kill traps.”
“The invasion of Aedes aegypti into central California has been of great concern especially as current control methods do not appear to be working very well,” said Cornel, who works closely with state's mosquito abatement personnel. “We have found that the Aedes aegypti have insecticide resistance genes which likely explains why their ultra-low volume (ULV) and barrier spray applications have not worked as well as expected. Work will be ongoing next year when the Aedes aegypti become active again after a brief slow overwintering period from November to March.”
A native of South Africa, Cornel received his doctorate in entomology, focusing on mosquito systematics, in 1993 from the University of the Witwatersrand, Johannesburg. He completed a post-doctoral fellowship with the Entomology Branch of the Centers for Disease Control and Prevention (CDC), Atlanta, before joining UC Davis in 1997 as an assistant professor and researcher.
How did he get involved in mosquitoes? “My interest in mosquito research started in the mid-1980s when I agreed to conduct a masters study under the guidance of Dr. Peter Jupp at the National Institute of Virology who researched West Nile and Sindbis viruses transmitted by mosquitoes in South Africa,” Cornel recalled. “Thereafter I continued to work on mosquitoes as a scientist employed at the South African Institute for Medical Research before moving to the USA.”
“Who would have thought that that the expertise that I gained on West Nile virus as a master student in South Africa would be used many years later after West Nile virus invaded and spread throughout the USA?”
For more than two decades, Cornel has teamed with fellow medical entomologist and “blood brother” Professor Gregory Lanzaro of the UC Davis School of Veterinary Medicine to study malaria mosquitoes in the West African country of Mali. Their work is starting to show significant results.
“Because of our commitment to conduct long term longitudinal studies and not static investigations,” Cornel said, “we have now shown that considerable selective processes are taking place causing spatiotemporal dynamics of gene flow and fitness events in major malaria vectors M (now Anopheles coluzzii) and S (now Anopheles gambiae) and M/S hybrids in West Africa.”
“We are currently establishing further evidence of the important role of insecticide resistance traits in spatiotemporal dynamics of Anopheles coluzzii, Anopheles gambiae and the Bamako form.” Cornel noted that these results have “considerably important implications in future efficacies of insecticide treated bednets to control indoor biting malaria vectors in West Africa.”
Cornel also teams with Lanzaro and Professor Heather Ferguson of the University of Glasgow to examine the ecology and associated genetics of the major malaria vector Anopheles arabiensis in Tanzania. They began working on the project four years ago.
One of his newest projects is the study of population/genetics, insecticide resistance and cytogenetics in the major malaria vector in Brazil. Cornel and Lanzaro launched their study in September when they traveled to Brazil to begin targeting the culprit, Anopheles darlingi, a “widely distributed species that has adapted to survive in multiple ecological zones and we suspect that it may consist of multiple incipient or closely related species,” Cornel said.
“While in Brazil I collected larvae and dissected salivary glands from them to examine their polytene chromosome inversion structure and polymorphisms,” Cornel related. “Inversions are vitally important to consider in genetic analyses and it takes considerable patience to interpret the chromosomes.”
Cornel and Lanzaro collaborate with Professor Paulo Pimenta of the Laboratory of Medical Entomology, René Rachou Research Centre- FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil. The UC Davis medical entomologists hope to produce good preliminary data from their research trip to write grants and establish a long-term project in Brazil.
Cornel also studies avian malaria. That interest sparked four years ago when he began working in Cameroon with scientists from UCLA and San Francisco State University (SFSU), including SFSU's Ravinger Sehgal, who studies avian blood parasites. Cornel's graduate student Jenny Carlson, in her final year of her Ph.D studies at UC Davis, is investigating avian malaria in Fresno County.
The Cornel-Carlson research implicates that considerable fidelity exists between Culex mosquito species and species of plasmodium they transmit. “This is contrary to the currently held belief that all Culex mosquitoes are equally capable of transmitting avian malaria,” Cornel said. “In our investigations, we described a new species of avian malaria which is very common in songbirds in Fresno County (published in Parasitology Research).”
Cornel plans to continue working with Sehgal investigating the effects of deforestation on transmission of avian parasites in Cameroon. They recently submitted a National Science Foundation grant proposal. “A large swath of primary forest is slated to be deforested in Cameroon and replaced with Palm oil plantations and we will investigate the effects of this hopefully, as it happens.”
Also new on the horizon: Cornel will be starting a new mosquito-borne virus project in February. He received a Carnegie Foundation scholarly three-month fellowship to work in South Africa (February through to April). The primary objective of the project? To examine mosquito-borne viruses cycling in seven national parks in South Africa and two National Parks in Bostwana.
“It's extremely difficult to get permission to conduct field research in national parks in Southern Africa and this provides an unprecedented exciting opportunity for me to work with a friend, Professor Leo Braack from the University of Pretoria, in these parks. One has to be very careful working in some of these parks at night because of the wild predators, elephants, hippos and buffalo.”
Cornel is active in the 30- member Center for Vectorborne Diseases (CVEC), headquartered in the UC Davis School of Veterinary Medicine and considered the most comprehensive vectorborne disease program in California. Both interdisciplinary and global, CVEC encompasses biological, medical, veterinary and social sciences.
Medical entomologist Anthony Cornel with a snake in Brazil.
UC Davis medical entomologists Anthony Cornel (foreground) and Gregory Lanzaro make annual trips to Mali to study malaria mosquitoes.
Bradley White, assistant professor at UC Riverside, will speak on “Ecological Genomics of Malaria Mosquitoes” at the UC Davis Department of Entomology seminar from 12:05 to 1 p.m. in Room 1022 of the Life Sciences Building, corner of Hutchison and Kleiber Hall drives.
Professor Gregory Lanzaro of the UC Davis School of Veterinary Medicine will introduce White. Plans call for video-recording the seminar for later posting on UCTV.
"Anopheles gambiae is the most important malaria vector in the world,” White says in is abstract. “Remarkable adaptive flexibility has enabled this mosquito to track humans across the diverse ecoclimates of sub-Saharan Africa where it thrives in both highly mesic and xeric conditions. These rapid, recent ecological adaptations have driven incipient speciation into two ecotypes, which differentially exploit permanent and temporary larval habitats. Within each nascent species, abundant chromosomal inversion polymorphisms facilitate adaptation to local conditions along latitudinal environmental gradients."
“To elucidate the genetic basis of ecological adaptation in Anopheles gambiae, we performed a series of genome-wide divergence scans, which revealed candidate regions subject to recent natural selection. Dissection of one of these genomic regions established a link between naturally occurring allelic variation and an adaptive phenotype. In the context of evolutionary genomics, these studies shed light on the maintenance of inversion polymorphisms and also provide insight into the genomic architecture of reproductive isolation. From a public health standpoint, this work demonstrates how divergent ecological selection can impact the vectorial capacity of Anopheles gambiae -- with consequences for malaria epidemiology and control.”
White began working on mosquitoes as an undergraduate at Oberlin College in Ohio. “At the time, West Nile virus (WNV) was sweeping through the midwest and during the summers I participated in a project to identify the Culex vectors of WNV and to determine environmental factors affecting their abundance,” he said. “After leaving Oberlin, I spent the next seven years in Nora Besansky's lab at Notre Dame where I focused on the population genomics of the African malaria mosquito Anopheles gambiae."
White, who joined the UC Riverside Department of Entomology faculty in 2011, focuses his research on quantitative and functional genomics of Anopheline malaria vectors.
More information? Check out his website at http://www.mosquitogenomics.org.
The malaria mosquito, Anopheles gambiae. (Photo by Anthony Cornel)
This year's event, set Wednesday, April 25 from 9 a.m. to 4 p.m. in Room 1031 of the Gladys Valley Hall, School of Veterinary Medicine, will include presentations on the historical, current and future efforts of malaria control, as well as updates on other vector biology research.
The UC Davis World Malaria Day is an opportunity "for students and researchers engaged in vector biology and genetics research to come together to discuss their research efforts,” said spokesperson Michelle Sanford, a postdoctoral scholar in the UC Davis Vector Genetics Lab.
The event supports World Malaria Day and the Roll Back Malaria Program in promoting education and research in the fight against malaria.
How did the UC Davis World Malaria Day observance originate? It was launched in 2007 by the (now folded) UC Mosquito Research Program, a UC Agricultue and Natural Resources program based in the UC Davis Department of Entomology and directed by medical entomologist Gregory Lanzaro. Lanzaro is now a professor in the Department of Pathology, Microbiology and Immunology of the School of Veterinary Medicine.
For the last several years, the Vector Genetics Lab has funded the World Malaria Day observance through a National Institutes of Health training grant.
Lanzaro and his "blood brother" medical entomologist Anthony Cornel direct the Vector Genetics Lab research programs. They've been doing research in Africa together for years. Cornel is an associate professor in the UC Davis Department of Entomology and a mosquito researcher at the Kearney Agricultural Research and Extension Center, Parlier.
The target: malaria, a mosquito-borne disease caused by infected Anopheles mosquitoes transmitting Plasmodium parasites.
The bad news is that more than half of the world's population is at risk for malaria. According to the World Malaria Report 2011, more than 216 million cases of malaria and an estimated 655 000 deaths occurred worldwide in 2010. Children in Africa are the still most susceptible to malaria; a child dies every minute of the disease.
The good news: Due to investments in malaria control, malaria mortality rates have dropped by more than 25 percent globally since 2000. Statistics show that malaria deaths in Africa have been cut by one-third within the last decade, according to the World Health Organization (WHO).
The strides we're making in tackling this massive killer are reflected in this year's World Malaria Day theme: "Sustain Gains, Save Lives: Invest in Malaria."
Sustain. Save. Invest. Well said.
Malaria mosquito, Anopheles gambiae. (Photo by Anthony Cornel)
UC Davis medical entomologist Anthony Cornel collecting mosquitoes. (Photo by Rory McAbee)
Postdoctoral researcher Rebecca “Becky” Trout-Fryxell (right), who studies Culex and Anopheles mosquitoes with University of California, Davis medical entomologists Anthony Cornel and Gregory Lanzaro, just received an award designating her as one of the top young entomologists in the nation.
Trout-Fryxell won one of the five John Henry Comstock Graduate Student Awards presented at the Entomological Society of America’s 58th annual meeting, held recently in San Diego. The Southwestern Branch of ESA selected her at its most outstanding entomology graduate student in a region encompassing Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, South Carolina and Tennessee, plus the U.S. territories of Puerto Rico and the U.S. Virgin Islands.
The other four ESA branches—Pacific, Eastern, North Central, and Southwestern Branch—also each selected a recipient.
Trout-Fryxell works with population genetics of the West Nile virus vector Culex pipiens, and does research on the malaria mosquito, Anopheles gambiae.
Fryxell joined the UC Davis team in April of 2009. Cornel is an associate professor of entomology, with offices and labs at UC Kearney Agricultural Center, Parlier, and UC Davis. Lanzaro is a professor in the Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine.
Trout-Fryxell previously won a Isley-Duport Entomology Scholarship and was a member of the 2007 Linnaean Games National Championship team from the University of Arkansas. The Linnaean Games is a college bowl-type competition featuring questions about insects, entomologists and entomological facts.
Trout-Fryxell has published her research in Journal of Medical Entomology, Journal of American Mosquito Control, Emerging Infectious Diseases, Medical and Veterinary Entomology, among others, on topics ranging from mosquitoes and ticks to bed bugs.
Trout-Fryxell received her master’s degree in entomology from the University of Kentucky, Lexington, where she studied with major professor Grayson Brown. Her research focused on reducing mosquito populations in the peridomestic environment.
She received her doctorate in entomology from the University of Arkansas, Fayetteville, last May. Studying with major professors Dayton Steelman and Allen Szalanski, she completed her dissertation on the distribution and occurrence of ticks in Arkansas, also examining tick-host pathogen interactions.
The four other winners of the coveted John Henry Comstock Awards:
Pacific Branch: Ashfaq Sial, Washington State University
North Central Branch: Anna Fiedler, Michigan State University
Southwestern Branch: Joe Lewis, University of North Texas
Eastern Branch: Gaylord Desurmont, Cornell
Back, in 2008, mosquito researcher Christopher Barker of the William Reisen lab at UC Davis won the Comstock award from the Pacific Branch.
Davis is definitely a good place to be for mosquito research!
It was a major milestone, sequencing the genome of Culex quinquefasciatus, the so-called “southern house mosquito.”
The research, spearheaded by UC Riverside geneticists and published in the Oct. 1, 2010 edition of Science, involved scientists from 37 other institutions. The mosquito is a medically important mosquito that transmits the West Nile virus, St. Louis encephalitis, lymphatic filariasis and other diseases.
UC Riverside research entomologist Peter Arensburger led the bioinformatics component of the multiyear research effort, launched in 2004.
Cornel collected and established the mosquito colony that was sequenced. Cornel is an associate professor of entomology at UC Davis who directs the mosquito research lab at UC Kearney Agricultural Center, Parlier.
“We have multiple sub colonies of the Johannesburg colony now established in numerous insectaries worldwide,” said Cornel.
Lanzaro, a longtime collaborator with Cornel, is a professor in the School of Veterinary Medicine and former director of the UC Mosquito Research Program and the Center for Vectorborne Diseases. Both Cornel and Lanzaro serve as graduate student advisors in the UC Davis Department of Entomology. They mentor future medical entomologists.
The Hammock lab played a role in annotating and examining divergence of esterases and glutathione-S tranferases in this mosquito. Bruce Hammock is a distinguished professor of entomology. The lab of Walter Leal, professor of entomology, added expertise in chemical ecology.
Cornel hailed the research as “another milestone in mosquito genomics—we now have a full genome sequence of a third medically important mosquito, Culex quinquefasciatus.”
Said Cornel: "This is the first species within the Culex genus fully sequenced and now offers many opportunities for research on comparative genomics and post genomics between three mosquito species now fully sequenced—namely the major malaria vector, Anopheles gambiae; the major dengue virus vector, Aedes aegypti; and a major vector of West Nile virus, Culex quinquefasciatus.”
The genome of Culex quinquefasciatus, Cornel said, is much larger than the other two species--52 percent more than Anopheles gambiae and 22 percent more than Aedes aegypti. “Research on these three mosquitoes--how they find their hosts and vector diseases and the mechanisms involved--will likely blossom in the near future.”
This is indeed research to watch.