- Author: Kathy Keatley Garvey
Filipa Rijo-Ferreira, a UC Berkeley School of Public Health (BPH) assistant professor who specializes in parasitology and circadian rhythms, will present a UC Davis Department of Entomology and Nematology seminar at 4:10 p.m., Wednesday, Oct. 19 on "Circadian Rhythms in Parasitic Diseases" in 122 Briggs Hall.
Her seminar also will be virtual. The Zoom link is https://ucdavis.zoom.us/j/95882849672. Host is molecular geneticist and physiologist Joanna Chiu, professor and vice chair of the UC Davis Department of Entomology and Nematology.
"Malaria's main symptom is the periodic fevers experienced by patients, fevers that ‘come and go' at certain times of the day and are a consequence of synchronized parasite rhythms," Rijo-Ferreira says in her abstract. "In humans, circadian clocks regulate multiple aspects of physiology, including sleep-wake cycles, metabolism, and immune defense. Circadian biology leads to body rhythms experienced by the pathogens that infect humans. In addition to sensing host rhythms, we recently discovered that parasites which cause devastating health burdens such as malaria and sleeping sickness diseases also have their own intrinsic clocks. The clocks of parasites regulate core biological functions from metabolism to the cell cycle, and the discovery of the existence of their clocks serves as an opportunity to access the molecular mechanisms regulating their rhythmic biology."
Rijo-Ferreira, trained in infectious diseases and neuroscience, joined the UC Berkeley faculty in January 2022. A native of Lisbon, Portugal, she holds a bachelor's degree in molecular and cellular biology from Nova University of Lisbon, and her master's degree in 2009 in molecular genetics and biomedicine from Imperial College, London. She received her doctorate in 2016 at the University of Porto, Portugal, where she completed her studies in basic and applied biology, molecular parasitology, and neuroscience. Postdoctoral training followed at the University of Texas Southwestern Medical Center, Dallas.
"Our lab is interested in parasitic infections and we study them under the lenses of time of day," she wrote on her lab website. "Our rhythmic world has been a driving force for organisms to evolve a molecular clock to anticipate such daily rhythms. Similarly, our own circadian biology leads to physiological rhythms that parasites experience.We study the single-celled parasites Plasmodium spp. that causes malaria, and Trypanosoma brucei that causes sleeping sickness. We employ technical approaches spanning from next-generation sequencing, to cellular and behavioral assays to investigate the interactions of these parasites with their hosts.Our work seeks to understand how circadian rhythms modulate host-parasite-vector interactions and identify opportunities in their rhythmic biology to treat parasitic infections
In an interview with BPH staff writer Eliza Partika, published in February 2022, she commented: "I am fascinated about our day and night cycles and how organisms evolved to anticipate them. I find it incredible that parasites, such as the ones that cause malaria, show a coordinated rhythmic pattern themselves, which underlies periodic fevers in infected individuals. Our research is aimed at understanding how this phenomenon is regulated molecularly, and how we can disrupt these rhythmic patterns to offset the infection."
"At BPH, we aim to set up a framework where we can explore the relationships between parasites, hosts, and the mosquitoes that serve as the vector of disease transmission, based on the time of day," Rijo-Ferreira related. "We hypothesize that the circadian rhythms of these three organisms need to be aligned in order for the parasite to cause an efficient infection. In fact, when rhythms are misaligned, there is a reduction in parasite levels. Thus, identifying the molecular players from host, parasite, and mosquito is essential to understanding this phenomenon and creating alternative strategies to manage deadly infections like malaria and sleeping sickness."
Rijo-Ferreira said she seeks to "bring to the attention the circadian aspect of infectious diseases and bring awareness of the potential benefits of time of day vaccination and drug treatment."
Emily Meineke, assistant professor of urban landscape entomology, UC Davis Department of Entomology and Nematology, coordinates the department's seminars for the 2022-23 academic year. All 11 seminars will take place both person and virtually at 4:10 p.m. on Wednesdays in Room 122 of Briggs Hall except for the Nov. 9th and Dec. 7th seminars, which will be virtual only, she said. (See list of seminars)
For further information on the seminars or to resolve any technical difficulties with Zoom, contact Meineke at ekmeineke@ucdavis.edu.
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- Author: Kathy Keatley Garvey
DAVIS--UC Davis undergraduate entomology researcher Jadrian Ejercito of the Shirley Luckhart lab won second place in the highly competitive student poster competition at the 99th annual meeting of the Pacific Branch of the Entomological Society of America (PBESA), held recently in Coeur d'Alene, Idaho.
His poster, on a malaria mosquito, was titled “Effects of Abscisic Acid on the Lifespan and Fecundity of Anopheles stephensi.” Ejercito was the only UC Davis entomology student to win a poster award.
For the project, he collaborated with his mentor, Shirley Luckhart, a professor in the Department of Medical Microbiology and Immunity and co-director of the Center for Vectorborne Diseases; and doctoral candidate Elizabeth Glennon of the Luckhart lab.
Judges scored the poster on 12 criteria, including abstract, presentation, introduction, objectives, results and discussion, and significance of the results.
Ejercito, a senior scheduled to receive his bachelor's degree in entomology in June, works in the Luckhart main lab as well as the Contained Research Facility.
A graduate of Nathaniel A. Narbonne High School in Harbor City, Los Angeles County, Ejercito joined the Luckhart lab as a MURALS scholar, a program dedicated to supporting undergraduate researchers. MURALS is an acronym for “Mentorship for Undergraduate Research in Agriculture, Letters an Science.” Formed in the spring of 1988, under the sponsorship of the Office of Student Affairs and the academic leadership of the College of Letters and Science, MURALS now includes students from all academic disciplines. Its mission is to encourage students to further their education beyond the baccalaureate.

- Author: Kathy Keatley Garvey
The lecture, "Anthropogenic Forces Drive the Breakdown of Reproductive Isolation between Incipient Species of the African Malaria Mosquito," is from 12:10 to 1 p.m. in Room 122 of Briggs Hall. Plans are to record the lecture for later viewing on UCTV.
Lanzaro, who researches malaria vectors in Africa and Brazil says his area interest is in medical entomology with a focus on the genetics of vectors of human disease. He initiated his current work on the population genetics of malaria vectors in Africa in 1991 when he joined the Laboratory of Malaria Research at the National Institutes of Health and continues this work through today.
"A considerable part of our research program involves field work," he said. "Over the years we have worked in seven countries spanning sub-Saharan Africa." His Africa work is organized into three major research areas: (1) Genetics of complex behavioral phenotypes, host preference and adult resting behavior (2) Mutations in immune signaling pathway genes and mosquito susceptibility to malaria infection and (3) Speciation in anopheline mosquitoes.
"Just this year we have initiated a new research program focused on the genetics malaria vectors in Brazil," Lanzaro related. The Brazilian government supports the program, known as Brazil Science without Borders. The focus is on the population genetics and genomics of the mosquito Anoheles darlingi, the principal vector of malaria in Brazil.
The abstract of his talk on Nov. 13: "The M and S forms of Anopheles gambiae have been the subject of intense study by both malaria researchers and evolutionary biologists.The focus has centered on evaluating models of the evolution and maintenance of genetic divergence between the two forms in relation to speciation. The two forms occur in sympatry throughout west and central Africa. Hybrids are rarely found in nature and studies of reproductive isolation confirmed strong assortative mating with inter-form matings estimated at a frequency of ~1%. Progeny of laboratory crosses and backcrosses show no signs of reduced fitness, however, it is widely held that, in nature, some degree of ecologically dependent postzygotic isolation, in addition to assortative mating, contributes to divergence between the two forms. Comparative genomics studies have revealed divergence occurs at three discrete islands in genomes that are otherwise nearly identical. Two opposing models aimed at describing the evolution of M and S have been formulated. An 'islands of speciation' model proposes that diverged regions contain “speciation genes” that are maintained by selection in the face of gene flow. An alternative 'incidental island' model maintains that gene flow between M and S is effectively zero and that divergence islands are unrelated to speciation. A 'Divergence Island SNP' (DIS) assay was developed and used to explore the spatial and temporal distributions of hybrid genotypes. Results revealed that hybrid individuals occur at frequencies ranging between 5-97% in every population examined. A temporal analysis of DIS genotype frequencies spanning 20 years was conducted at a single site. This study revealed that assortative mating is unstable and periodically breaks down resulting in extensive hybridization. Results suggest that hybrids suffer a fitness disadvantage, but at least some hybrid genotypes are viable. Stable introgression of the 2L speciation island occurred at this site following a hybridization event. We present data suggesting that strong selection on a single gene within the 2L island is driving M/S introgression and that man-made changes to the environment is the source of this selection."
Lanzaro joined PMI in July 2006. He served as the director of the Center for Vectorborne Diseaes, UC Davis, from January 2006 through June 2007, and directed the UC Mosquito Research Program, headquartered in the UC Davis Department of Entomology, from June 2002 to 2008.
Prior his appointment at UC Davis, Lanzaro served on the faculty of Department of Pathology, University of Texas Medical Branch, Galveston, Texas, from August 1995 through May 2002, advancing from assistant and associate to full professor.
Lanzaro received his bachelor of science degree in biology/secondary education from Kansas State University, Manhattan, Kansas in 1972; his master's degree in entomology in 1978 from the Univeristy of Arizona, Tucson, and his doctorate in engomology in 1986 from the University of Florida.
The medical entomologist did post-doctoral work at three universities: from 1986 to 1988 in the Department of Entomology, Mississippi State University; from 1986 to 1988 in the Department of Entomology, Missisippi State University; and from 1988 to 1991 in the UC Davis Department of Entomology. He was a MacArthur Fellow in the Laboratory of Malaria Research, National Institutes of Health.
