- Author: Kathy Keatley Garvey
Her seminar takes place at 3:30 in 366 Briggs Hall, and also will be on Zoom.
Mack studies Aedes aegypti with a focus on analysis of transcriptomic datasets and 3D imaging datasets. "Throughout my time in graduate school, my projects have considered pyrethroid resistance in Aedes aegypti ;examining the genetic response to this insecticide. As I finish up my dissertation, I hope to pursue a career in industry using the skills I've developed to continue to analyze large datasets!"
Insecticide resistance is a global issue, Mack says in her exit seminar abstract. Ae. aegypti, known as "the yellow fever mosquito," can transmit dengue fever, chikungunya, Zika fever, Mayaro and yellow fever viruses, and other disease agents. The mosquito was first colonized California in 2013 and arrived resistant to pyrethroids. "The pyrethroid target site genotype differs geographically in California and partially infers resistance phenotype, indicating that other mechanisms are at play as well."
"Since their detection in 2013, Aedes aegypti has become a widespread urban pest in California," the co-authors wrote in the abstract. "The availability of cryptic larval breeding sites in residential areas and resistance to insecticides pose significant challenges to control efforts. Resistance to pyrethroids is largely attributed to mutations in the voltage gated sodium channels (VGSC), the pyrethroid site of action. However, past studies have indicated that VGSC mutations may not be entirely predictive of the observed resistance phenotype."
"To investigate the frequencies of VGSC mutations and the relationship with pyrethroid insecticide resistance in California, we sampled Ae. aegypti from four locations in the Central Valley, and the Greater Los Angeles area. Mosquitoes from each location were subjected to an individual pyrethrum bottle bioassay to determine knockdown times. A subset of assayed mosquitoes from each location was then analyzed to determine the composition of 5 single nucleotide polymorphism (SNP) loci within the VGSC gene."
The conclusion:
"Resistance associated VGSC SNPs are prevalent, particularly in the Central Valley. Interestingly, among mosquitoes carrying all 4 resistance associated SNPs, we observe significant heterogeneity in bottle bioassay profiles suggesting that other mechanisms are important to the individual resistance of Ae. aegypti in California."
Mack, who holds a bachelor of science degree (2018) in biology from Creighton University, Omaha, Neb., enrolled in the UC Davis graduate school program in 2018.
Active in the Entomological Society of America, Mack scored second place in student competition at the 2022 joint meeting of the Entomological Societies of America, Canada, and British Columbia, held last November in Vancouver, British Columbia. She entered her presentation, "Three Dimensional Analysis of Vitellogenesis in Aedes aegypi Using Synchrotron X-Ray MicroCT,” in the category, "Graduate School Physiology, Biochemistry and Toxicology: Physiology.
Her abstract: "Traditional methods of viewing the internal anatomy of insects require some degree of tissue manipulation and/or destruction. Using synchrotron-based x-ray phase contrast microCT (pcMicroCT) avoids this issue and has the capability to produce high contrast, three dimensional images. Our lab is using this technique to study the morphological changes occurring in the mosquito Aedes aegypti during its reproductive cycle. Ae. aegypti is the primary global arbovirus vector, present on all continents except Antarctica. Their ability to spread these viruses is tightly linked with their ability to reproduce, as the production of eggs in this species is initiated by blood feeding. Amazingly, this species produces a full cohort of eggs (typically 50-100) in just 3 days' time following a blood meal. This rapid development represents dramatic shifts in physiological processes that result in massive volumetric changes to internal anatomy over time. To explore these changes thoroughly, a time course of microCT scans were completed over the vitellogenic period. This dataset provides a virtual representation of the volumetric, conformational, and positional changes occurring in tissues important for reproduction across the vitellogenic period. This dataset provides the field of vector biology with a detailed three-dimensional internal atlas of the processes of vitellogenesis in Ae. aegypti."
"As for career plans, I am applying to computational biology positions in industry," Mack said. "I'm not filing my dissertation until July so I am still working on this."
- Author: Kathy Keatley Garvey
His presentation also will be virtual. The Zoom link:
https://ucdavis.zoom.us/j/95882849672.
Zach, a member of Professor Phil Ward's laboratory, says in his abstract: "Ants belonging to the subfamily Leptanillinae (Hymenoptera: Formicidae) are sister to nearly all other extant Formicidae. Miniscule and subterranean, little is known of them. Contrary to the collecting bias observed in most Formicidae, male leptanilline specimens are acquired more easily than workers or queens. The sexes are almost never collected together, and certain groups are known from males only—some of these being so bizarre as to not resemble ants at all. These restrictions obstruct our understanding of evolutionary relationships among the Leptanillinae."
"My thesis is aimed at leptanilline taxonomy that reflected phylogeny and integrated morphological data from both sexes. I here present the culmination of this work, reliant on phylogenomic inference from ultra-conserved elements (UCEs), supplemented by total-evidence inference from male morphological data and UCEs. I also here summarize my exploration of leptanilline male genital skeletomusculature, a surreal vista illuminated by micro-computed tomography, in collaboration with Ziv Lieberman and others."
Griebenow will be filing his dissertation before May 19. He joined the Ward lab in September 2017. He holds a bachelor of science degree (2017) in agriculture (entomology) from The Ohio State University. He graduated magna cum laude. He minored in music.
Griebenow was a member of the UC Davis Linnaean Games team (now renamed Entomology Games) that won two national championships (2018 and 2022) at the Entomological Society of America (ESA) meetings. He also was a member of Ohio State's Linnaean Games team that won second place in the 2017 national championship.
His publication list includes:
Griebenow, Z. H., Isaia, M., and Moradmand, M. (2022). Discovery of a troglomorphic ant (Hymenoptera: Formicidae: Leptanillinae: Yavnella laventa sp. nov.) in southwestern Iran, with the first description of the worker caste of Yavnella Kugler. Invertebrate Systematics, 36, 1118-1138.
Griebenow, Z. H. (2021). Synonymisation of the male-based ant genus Phaulomyrma (Hymenoptera, Formicidae) with Leptanilla based upon Bayesian total-evidence phylogenetic inference. Invertebrate Systematics, 35(6), 603-636.·
Griebenow, Z. H. (2020). Morphological and phylogenomic delimitation of tribes in the subfamily Leptanillinae (Hymenoptera: Formicidae), with a description of the male of Protanilla lini Terayama, 2009. Myrmecological News, 30, 229-250.
Department seminar coordinator is urban landscape entomologist Emily Meineke, assistant professor. For technical issues (Zoom), she may be reached at ekmeineke@ucdavis.edu. (See complete list of spring seminars.)
- Author: Kathy Keatley Garvey
Winokur will discuss "Temperature Drives Transmission of Mosquito-borne Pathogens: Improving Entomological Estimates for Aedes aegypti-borne Virus Transmission Risk." Her seminar will be both in-person and virtual. The Zoom link:
https://ucdavis.zoom.us/j/95882849672.
"The mosquito Aedes aegypti is the primary vector of a range of viruses that cause a major burden on human health worldwide, including dengue, Zika, chikungunya, and yellow fever viruses," Winokur writes in her abstract. "As the Zika epidemic emerged in 2016, estimates for Zika risk were based on proxy evidence from closely related dengue virus. To improve risk estimates, we studied how temperature affects Zika virus extrinsic incubation period. We sought to further improve risk estimates by studying thermal preferences of Ae. aegypti mosquitoes in the laboratory and in the field. Current mosquito-borne pathogen risk models primarily use temperatures from weather stations or thermal imagery as a proxy for the temperatures mosquitoes experience, however such approaches do not account for local environments or microclimates available to adult mosquitoes. Taken together, the results of these studies can be used to improve prediction of mosquito-borne pathogen risk and inform mosquito control decisions."
A doctoral student at UC Davis since 2016, Winokur is studying for her PhD in entomology with a designated emphasis in the biology of vector-borne diseases. She will submit her dissertation in October and officially graduate then, "although I participated in the doctoral ceremony in June," she related. "I will be a postdoc in the Barker lab working with VectorSurv (https://vectorsurv.org/), and also have a PacVec postdoctoral fellowship (https://pacvec.us/) to dedicate 25 percent of my time to "Enriching Practical Learning Resources for Entomological, Medical, and One-Health Curricula.'
Olivia received her bachelor's degree in May of 2015 from Cornell University where she was an interdisciplinary studies major (environmental effects on human health).
At UC Davis, Winokur served as the 2019-2020 president of the Entomology Graduate Student Association and as a 2020-2022 committee member of the UC Davis Entomology Diversity, Equity, Inclusion, & Belonging. She co-founded the Girls' Outdoor Adventure in Leadership and Science (GOALS) in 2017 and continues to serve in leadership roles. GOALS is a free two-week summer science program for high school girls and gender expansive youth from backgrounds underrepresented in STEM fields. They learn science, outdoors skills, and leadership hands-on while backpacking in Sequoia National Park.
In academic leadership, Winokur co-developed a Stanford course in 2019 on "How Vector-Borne Diseases Have Shaped Human History" and co-developed a syllabus and mentored students. She also co-developed a UC Davis course (2019, 2019, 2020) with other entomology graduate students on "The Natural History of Insects." She has served as both a teaching assistant and lecturer, as well as a mentor.
Active in the vector-borne disease community, Winokur completed a 2019-2020 term as the Executive Council student representative for the American Committee on Medical Entomology (ACME) and as a 2017-2019 volunteer with the Vector-Borne Disease Section of the California Department of Public Health, where she assisted with hantavirus and plague surveillance. She peer-reviews manuscripts for the Journal of Medical Entomology.
Winokur is the recipient of numerous fellowships and grants, including a $140,00 National Science Foundation Graduate Research Fellowship; a $30,000 Pacific Southwest Center of Excellence in Vector-Borne Diseases Graduate Fellowship; a $25,000 Pacific Southwest Center of Excellence in Vector-Borne Diseases Postdoctoral Fellowship; a Professors for the Future Fellowship (UC Davis) of $3,000; and two-consecutive Hazeltine Student Research Awards (UC Davis), totaling $5,500. She also received an American Geophysical Union Centennial Grant of $9,720 and an American Association for University Women Community Action Grant of $5,000 (outreach grants).
Winokur's latest peer-reviewed publications include co-authoring "The Influence of Vector-borne Disease on Human History: Socio-Ecological Mechanisms" in the journal Ecology Letters; and serving as the lead author of "Impact of Temperature on the Extrinsic Incubation Period of Zika Virus in Aedes aegypti in the journal PLOS (Public Library of Science): Neglected Tropical Diseases.
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 technical difficulties with Zoom, contact Meineke at ekmeineke@ucdavis.edu.
