The Zoom seminar, open to all interested persons, will take place from 4:10 to 5 p.m. Click here for the form to obtain the Zoom link to connect.
"In this talk, we are going to demonstrate the tripartite interactions between the microbiome, mosquitoes of the genus Aedes and Zika virus that they transmit," she says. Aedes albopictus is also known as the Asian tiger mosquito.
"My research focuses on the tripartite interactions between the microbiome, mosquitoes as vectors and the arboviruses they transmit," Onyango says. "In addition, I am interested in the role the vector-host- pathogen interface plays in enhancing disease severity in the vertebrate host. The goal of my research is to develop innovative control mechanisms both for the vector and pathogens they transmit."
Host is medical entomologist-geneticist Geoffrey Attardo, assistant professor, UC Davis Department of Entomology and Nematology. Cooperative Extension specialist and assistant professor Ian Grettenberger coordinates the fall seminars.
"Dr. Maria Onyango works on the biology underlying interactions between arboviruses (Zika virus), vector mosquitoes and the associated microbiome," Attardo said.
Along with seven other scientists, Attardo and Onyango co-authored a research article in the Oct. 2nd edition of Frontiers in Microbiology on"Zika Virus Infection Results in Biochemical Changes Associated With RNA Editing, Inflammatory and Antiviral Responses in Aedes albopictus."
"Rapid and significant range expansion of both the Zika virus (ZIKV) and its Aedes vector species has resulted in the declaration of ZIKV as a global health threat. Successful transmission of ZIKV by its vector requires a complex series of interactions between these entities including the establishment, replication and dissemination of the virus within the mosquito. The metabolic conditions within the mosquito tissues play a critical role in mediating the crucial processes of viral infection and replication and represent targets for prevention of virus transmission. In this study, we carried out a comprehensive metabolomic phenotyping of ZIKV infected and uninfected Ae. albopictus by untargeted analysis of primary metabolites, lipids and biogenic amines. We performed a comparative metabolomic study of infection state with the aim of understanding the biochemical changes resulting from the interaction between the ZIKV and its vector. We have demonstrated that ZIKV infection results in changes to the cellular metabolic environment including a significant enrichment of inosine and pseudo-uridine levels which may be associated with RNA editing activity. In addition, infected mosquitoes demonstrate a hypoglycemic phenotype and show significant increases in the abundance of metabolites such as prostaglandin H2, leukotriene D4 and protoporphyrinogen IX which are associated with antiviral activity. These provide a basis for understanding the biochemical response to ZIKV infection and pathology in the vector. Future mechanistic studies targeting these ZIKV infection responsive metabolites and their associated biosynthetic pathways can provide inroads to identification of mosquito antiviral responses with infection blocking potential."
Onyango holds two degrees from the University of Nairobi, Kenya: a bachelor of science degree in biochemistry and zoology and a master's degree in applied parasitology. She received her doctorate in veterinary entomology from Deakin University and Australian Animal Health Laboratory, Commonwealth Scientific and Industrial Research Organisation (CSIRO), and then completed postdoctoral training at the Yale School of Public Health, Department of Epidemiology of Microbial Diseases.
For any technical issues regarding the seminar, contact Grettenberger at firstname.lastname@example.org
Despite COVID-19 pandemic precautions and constraints, the California Master Beekeeper Program (CAMBP), headquartered at the University of California, Davis, has certified its first-ever Master Beekeeper: Amy Hustead of Grass Valley, a veteran beekeeper who also happens to be the first and only beekeeper in her family.
Hustead, president of the Nevada County Beekeepers Association and a veterinary technician, recently passed the Master-level beekeeper certification process.
CAMBP, founded and co-directed by Extension apiculturist Elina Lastro Niño of the UC Davis Department of Entomology and Nematology, uses science-based information to educate stewards and ambassadors for honey bees and beekeeping. It offers three levels of certification (Apprentice, Journey and Master). Niño launched the first Apprentice class in 2016.
Hustead's passion is education and outreach, said Niño and CAMBP manager Wendy Mather.
Hustead's Master Capstone project involved teaching two, three-hour online CAMBP classes (“Planning Ahead for Your First Hives,” and “Working Your Colonies.”) She designed, developed and successfully delivered "Intermediate Backyard Beekeeping," an in-depth, online, four-hour course on science-based beekeeping for the hobbyist and sideliner. Topics included winter and spring preparation, swarm prevention, active swarming, splits and nucs (nucs, or nucleus colonies, are small colonies created from larger colonies), diseases, nutrition, maximizing honey production, and harvesting honey, wax, propolis and pollen.
Amy Hustead, a wife, mother of 9-year-old twin boys, and a seven-year beekeeper, said she really enjoys CAMBP. “It has allowed me to meet some really excellent beekeepers. I plan to continue to teach classes and help educate people on the biology of bees.”
What fascinates Hustead about bees? “When I was in college I studied sociobiology, which is a field of biology that explains social behavior in terms of evolution,” she said. “I have always been fascinated by the cross section of evolution and behavior. Bees are the epitome of social insects. Everything they do is for the good of the whole.”
“I dabbled in homesteading when I first moved to the foothills, and like a lot of people, started out keeping chickens. I think I wanted to get goats but my husband was not on board, so I decided to get bees instead.”
As a veterinary technician, she works in low-cost spay and neuter programs. "I also volunteer with an organization that provides veterinary care to pets of homeless and low-income people in the Sacramento area."
Bees keep her occupied at several locations. “I have between 15-20 personal colonies at three different locations,” Hustead related. ”I also manage a few colonies for other people.”
As it turns out, this year is not a good year for bees. “Mostly my bees aren't doing well this year,” she said. “The nectar flow was non-existent, and the recent fires haven't helped. For the first year ever I am harvesting no honey from my yard at home.”
Hustead home-schools her twins. “I am very serious about home-schooling my kids, and part of our curriculum is extensive travel.” The Hustead family has visited a number of states in the nation, and has already been to Mexico, Ireland, Costa Rica. “We are planning a Europe trip as soon as possible.“
“This year, despite COVID-19 constraints, the California Master Beekeeper Program continues its mission of using science-based information to educate stewards and ambassadors for honey bees and beekeeping, by moving its courses and exams online,” Mather said.
CAMBP's current 53 Apprentice candidates will take their online exam Sept. 12. To pass, they must score at least 75 percent. “Candidates will upload videos or partake in 'live from their apiary' Zoom sessions to satisfy the requirements of the practical rubric,” Mather said.
The Journey-level candidates have completed the online written portion of their certification and their videos and Zoom practicals are in progress. “So far, we're proud to announce that all 15 Journey level candidates scored above 80 percent on their written exams, and their videos and Zoom practicals are looking great!” Mather commented.
The Master level usually takes an average of five years to achieve. Some candidates choose to remain as Apprentice or Journey-level beekeepers. CAMBP offers pre-approved Master Capstone Tracks, but also encourages candidates to follow their passion if their favorites are not on the list, which includes:
- Native Bees and Pollinator Gardens
- Commercial Beekeeping
- Scientific Research
- Education and Outreach
- Policy for Honey Bees and Native Pollinators
Seven Master-Level Candidates
The seven Master-level candidates for the 2020-21 season are pursuing a variety of projects, including mapping drone congregation areas, authoring a book on the history of honey in ancient Greece, establishing a pollen library for the state of California, starting a commercial beekeeping business, and training a “detector dog” in the apiary.
To maintain active status as a Master Beekeeper with CAMBP, members are required to perform and log 25 hours of BEEs (Beneficial Education Experiences). Hustead will perform a minimum of 25 volunteer hours annually. Her volunteer service, at the minimum, is valued at $25.43 per hour or about $600 per year.
“Amy will have no problem doing that as she's active as the president of her local beekeeping club,” Mather said, “and she mentors many new beekeepers to help them become science-based stewards and ambassadors of honey bees and beekeeping.”
The UC Davis Honey and Pollination Center at the Robert Mondavi Institute is gearing up for two virtual events, one in September and the other in October:
- "Sips and Bites: The Hidden World of Honey" from 6 p.m. to 7 p.m., Wednesday, Sept. 9 on Zoom.
- Honey Sensory Workshop from 8 a.m. to 1:30 p.m.on Thursday, Oct. 22.
Honey Sensory Workshop
Amina Harris, director of the Honey and Pollination Center, said the Honey Sensory Workshop is a "one-day immersion into the complex world of honey. Each student will be guided through tastings and discussions laying the groundwork to understand the variety and nuance of honey." Master presenters are master taster and Italian Certified Expert Honey Taster, Orietta Gianjorio and Amina Harris, educator and founding director and the co-owner of Z Specialty Food, LLC, Woodland.
The course will cover all the basics through lectures and tastings including:
- Sensory evaluation and descriptive analysis
- Mono-varietal honeys
Registration closes Oct. 1. The cost is $160. More information is here.
Sips and Bites: The Hidden World of Honey
This event is part of the Sips and Bites series, "which explores the stories behind foods and drinks with winemakers, brewers, and culinary innovators with tastings and conversations about what inspires them to make their wines, beers, and foods," said Harris, who will serve as moderator. Registration is underway.
Trevor and Claire Tauzer, founders of Sola Bee Farms, Woodland, will discuss how sustainable beekeeping is key to the future of agriculture. They will elaborate on what goes into making honey from a single floral source and yield information about the taste.
Trevor Tauzer, beekeeper and general manager of Tauzer Apiaries/Sola Bee Farms, created Sola Bee Farms in 2011 to sell the family's varietal honey directly to customers. He grew up beekeeping with his father, and following his graduation from UC Santa Cruz, returned to beekeeping in 2008. Trevor says he enjoys running his second-generation family business with his wife Claire, and teaching their 3.5 year old and 1-year-old about honey bees.
Claire Tauzer is the community outreach and brand manager of Tauzer Apiaries/Sola Bee Farms. A former high school teacher, she applies her educational background to help communicate and promote the importance of professional pollination and the benefits of local varietal honey. Sola Bee Farm's Wild Blackberry honey won a Good Food Award in 2019.
Registrants are asked to order a special three-pack of Sola Bee Farms honey (cost is $30) by Wednesday, Sept. 2 to ensure arrival by Wednesday, Sept. 9. (See more information)
The Honey and Pollination Center's recently scheduled Mead Making 301 course, initially set Sept. 14-17, has been canceled.
(Editor's Note: Geoffrey Attardo, assistant professor, UC Davis Department of Entomology and Nematology, published this piece July 29, 2020 on The Conversation website. This article is republished from The Conversation under a Creative Commons license. Read the original article.)
Bloodthirsty tsetse flies nurse their young, one live birth at a time – understanding this unusual strategy could help fight the disease they spread
Tsetse flies are bloodthirsty. Natives of sub-Saharan Africa, tsetse flies can transmit the microbe Trypanosoma when they take a blood meal. That's the protozoan that causes African sleeping sickness in people; without treatment, it's fatal, and millions of people are at risk due to the bite of a tsetse fly.
My entomology research focuses on insects that feed on the blood of people and animals. From a human health standpoint, understanding what makes all these bugs tick is key to developing ways to control them and prevent transmission of the diseases they carry, such as malaria, dengue, Lyme disease, West Nile virus and many others.
Tsetse flies stand out from their blood-feeding cousins the mosquitoes and ticks because of their unique reproductive biology. They give birth to live young and, even more unusual, the mother lactates and provides milk for her offspring. Here's how it all works – and why their unusual reproduction strategy might be a key to controlling tsetse flies and the parasite they carry once and for all.
From egg to larva
Scientists know of other flies that hold onto their eggs in their reproductive tract until they hatch into young larvae, with each brood consisting of dozens of offspring. The mother then tries to find a suitable source of nutrition in the environment, deposits the larvae and leaves them to survive on their own. The mother does not provide any nutrition for her young.
That's the standard fly way of life. Tsetse flies take a different approach.
Female tsetse flies develop just one single egg at a time. When the egg is complete, the mother moves it from her ovaries into her uterus in a process called ovulation. Once in the uterus, the egg is fertilized with sperm the female has stored in an organ called the spermatheca. While females can mate multiple times, they obtain all the sperm they need for their lifetime from a male fly during a single mating event.
After fertilization, the female keeps the egg in her uterus for five days while an embryo develops within the egg. When the embryo is ready, the egg hatches in the uterus of the female and the tsetse fly larva begins its life living inside its mother's uterus.
Milk meals for baby
Here's where tsetse flies dramatically diverge from most other insects.
Attached to the mother's uterus is a specialized gland that makes a milk-like substance. The organ is called the milk gland, and it produces a rich mixture of fats and particular proteins that provide the larva with all the nutrition it needs to develop into an adult.
Just like in mammals, the milk also transfers beneficial bacteria from the mother to the offspring. These bacteria are essential for tsetse flies, and without them adult female flies are unable to reproduce.
After five or six days of developing and feeding on milk, the larva is fully grown and ready to enter the world. The mother finds a safe spot and gives birth. The larva immediately burrows underground to avoid predators and parasites.
Once buried, the outer surface of the larva's skin hardens and turns black, forming a protective shell. This is called the pupal stage and it lasts for around three weeks. During this time, the pupa transforms into an adult fly.
It then emerges from the pupa, climbs out of the ground, and begins its life as an adult tsetse fly looking for hosts to blood-feed on and other tsetse flies to mate with.
Why live birth?
Why would an insect evolve this slow and resource-intensive way to reproduce?
One idea is that this method provides a defensive advantage relative to free-living larvae against parasites and predation. Larvae on their own have few (if any) ways to defend against these threats. But keeping larvae in the mother's uterus provides shelter and a guaranteed food source. While this strategy is much slower, scientists think the extra maternal care results in higher larval survival rates. It's a matter of quality over quantity.
A result of this reproductive strategy is that tsetse fly populations are small and slow to recover from control efforts, relative to more prolific insects like mosquitoes.
My colleagues and I hope that we can parlay our understanding of the molecular processes that regulate tsetses' milk production and mating behavior into new environmentally friendly, cost-effective and tsetse-specific control strategies for these insects.
The sleeping sickness tsetse flies spread is a potential issue for millions of people in 36 sub-Saharan countries, though the number of annual cases has decreased drastically thanks to major control efforts – including trapping flies, applying insecticides and releasing sterile males to the environment where they mate with wild females but don't produce offspring. Ultimately, we'd like to contribute to the World Health Organization's goal of eliminating African sleeping sickness by 2030 with a new way to prevent the transmission of disease-causing trypanosomes to people and animals./h2>/h2>/h2>/figcaption>/h1>
Researchers from Harvard Medical School and the University of California, Davis, blocked the progression of cancer growth caused by environmental carcinogens and food contaminants by resolving an eicosanoid/cytokine storm triggered by cell debris.
The research, from the laboratories of physician-researcher Dipak Panigrahy of Harvard Medical School and UC Davis distinguished professor Bruce Hammock, is published in the current edition of the Proceedings of the National Academy of Sciences.
“We advanced the hypothesis that cell debris from chemotherapy, resection of tumors and even immunotherapy can make these therapies a double-edged sword stimulating cancer growth and metastasis while treating it,” said Hammock, who holds a joint appointment in the UC Davis Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center.
In their paper, “Resolution of Eicosanoid/Cytokine Storm Prevents Carcinogen and Inflammation-Initiated Hepatocellular Cancer Progression,” the scientists covered the potent environmental carcinogen and food contaminant aflatoxin. Aflatoxins are toxins produced by certain fungi that are found in such agricultural crops as corn, peanuts, cottonseed, and nuts.
“Not only is this fungal metabolite genotoxic but it is also a tumor promoter,” said Hammock, defining a genotoxic agent as “a chemical that damages cellular DNA, resulting in mutations or cancer.”
Lead authors Anna Fishbein of Harvard University, a recently enrolled medical student in the Georgetown University School of Medicine, and Weicang Wang, a postdoctoral scholar in the Hammock lab, said aflatoxin exerts some of its cancer-promoting effects by generating cell debris which activate a pathway leading to eicosanoid and cytokine storms. These two classes of natural chemical mediators, they explained, control many of our defenses against pathogens, but when out of control, these storms lead to growth and metastasis of liver cancer.
“We demonstrated that debris generated by aflatoxin B1accelerates tumor dormancy escape in liver cancer models by stimulating a macrophage-derived eicosanoid and cytokine storm of pro-inflammatory mediators,” said Fishbein. “Thus, targeting a single inflammatory mediator or eicosanoid pathway is unlikely to prevent carcinogen-induced tumor progression.”
The researchers showed that the inhibition of the soluble epoxide hydrolase (sEH) pathway or the combined inhibition sEH and cyclooxygenase-2 (COX-2) pathways prevented the carcinogen debris-induced storm of both cytokines and lipid mediators by macrophages--specialized detect-and-destroy cells.
In animal models, the dual COX-2/sEH inhibitor PTUPB prevented the onset of debris-stimulated liver cancer. The dual inhibition of COX-2/sEH pathways may be “a novel approach” to control cancer of the liver, the researchers said.
“We also showed that carcinogen-generated debris stimulates an endoplasmic reticulum (ER) stress response which may promote HCC progression. Importantly, PTUPB prevents the ER stress response,” Wang added. “We created a novel model of debris-stimulated liver cancer designed to study new strategies for the prevention and treatment of carcinogen-induced cancers with tremendous potential to translate to the clinic.”
From a nutritional standpoint, aflatoxin is a common food contaminant, Wang said. “But good agricultural practice and post-harvest technology keep the levels very low. However, in much of the world, aflatoxin levels are so high that many crops are discarded. In other cases, these contaminated grain and nut crops enter the human food chain, where they cause acute toxicity, severe anemia and of course later lead to cancer.”
UC Davis co-author and nutritional scientist Yuxin Wang (who is the wife of Weicang Wang) said that “finding a way to modulate the events that lead to the eicosanoid storm would have a major effect on children's health in many developing countries.”
Fishbein and Allison Gartung of the Panigrahy lab not only used the soluble epoxide hydrolase inhibitors from the Hammock lab but also used some prototype drugs synthesized by chemist Sung Hee Hwang of the UC Davis School of Veterinary Medicine “which proved to be even better,” Hammock said.
“These compounds are a synthetic combination of cyclooxygenase inhibitors like celebrex with epoxide hydrolase inhibitors,” Hammock said. “Since epoxide hydrolase inhibitors stabilize the endoplasmic reticulium stress response and transcriptionally down regulate inflammatory cyclooxygenase we expected them to synergize with cyclooxygenase inhibitors. We were surprised and pleased with the dramatic interaction of these inhibitors when combined in the same molecule in reducing the cytokine and eicosanoid production by in response to cell debris.”
“The observations from Harvard show that by inhibiting soluble epoxide hydrolase, we can block the activation of these inflammatory cascades leading to tumor promotion, growth and metastasis,” Hammock said. “We have a compound in human clinical trials that inhibits sEH, which should be clinically available in a few years. In addition. we have found natural inhibitors of the epoxide hydrolase in a variety of plants, including crop plants. This may allow us to reduce the cancer risk and block the gastrointestional erosion and bleeding caused by dietary aflatoxin using natural means.”
Other members of the 15-member team are UC Davis researchers Jun Yang, Yuxin Wang and Sung Hee Hwang; Harvard researchers Haixia Yang, Victoria Hallisey, Jianjun Deng, Sanne Verheul, Allison Gartung, Diane Bielenberg and Mark Kiernan (now of Bristol-Myers Squibb); and Sui Huang, Institute for Systems Biology, Seattle. Hammock and Panigrahy are the corresponding authors.
The research drew strong financial support as the Panigrahy's laboratory is generously supported by the Credit Unions Kids at Heart Team, the CJ Buckley Pediatric Brain Tumor Fund, and the Joe Andruzzi Foundation; and Hammock's UC Davis grants from the National Institute of Environmental Health (NIEHS) Superfund Research Program, and the NIEHS RIVER Award (Revolutionizing Innovative, Visionary, Environmental Health Research).
Hammock, a member of the UC Davis faculty since 1980, has directed the UC Davis Superfund Research Program for nearly four decades. It supports scores of pre- and postdoctoral scholars in interdisciplinary research in five different colleges and graduate groups on campus. Last year Hammock received a $6 million, eight-year “Outstanding Investigator” federal grant for his innovative and visionary environmental health research: The award is part of the Revolutionizing Innovative, Visionary Environmental Health Research (RIVER) Program of NIEHS.
“Toxic environmental carcinogens promote cancer via genotoxic and nongenotoxic pathways, but nongenetic mechanisms remain poorly characterized. Carcinogen-induced apoptosis may trigger escape from dormancy of microtumors by interfering with inflammation resolution and triggering an endoplasmic reticulum (ER) stress response. While eicosanoid and cytokine storms are well-characterized in infection and inflammation, they are poorly characterized in cancer. Here, we demonstrate that carcinogens, such as aflatoxin B1 (AFB1), induce apoptotic cell death and the resulting cell debris stimulates hepatocellular carcinoma (HCC) tumor growth via an ‘eicosanoid and cytokine storm.' AFB1-generated debris up-regulates cyclooxygenase-2 (COX-2), soluble epoxide hydrolase (sEH), ER stress-response genes including BiP, CHOP, and PDI in macrophages. Thus, selective cytokine or eicosanoid blockade is unlikely to prevent carcinogen-induced cancer progression. Pharmacological abrogation of both the COX-2 and sEH pathways by PTUPB prevented the debris-stimulated eicosanoid and cyto- kine storm, down-regulated ER stress genes, and promoted macrophage phagocytosis of debris, resulting in suppression of HCC tumor growth. Thus, inflammation resolution via dual COX-2/sEH inhibition is an approach to prevent carcinogen-induced cancer.”