In a groundbreaking discovery, a scientific team of Brazilians and Brazilian-born chemical ecologist Walter Leal of the University of California, Davis, has announced that the Zika virus has been detected in wild-caught Culex quinquefasciatus mosquitoes in Recife, the epicenter of the Zika epidemic.
Scientists from the Fiocruz Institute, Pernambuco, confirmed the discovery July 21. The detection could have widespread repercussions, as the Culex mosquitoes are more common and widespread than the yellow fever mosquito, Aedes aegypti, known as the primary carrier of the Zika virus.
Leal, who collaborates with Fiocruz Institute researcher Constancia Ayres in a National Institutes of Health-sponsored project on the investigation of Zika in the C. quinquefasciatus, said that the Brazilian lab earlier discovered that Culex had the capability of transmitting the virus. Although the scientists were able to infect the lab mosquitoes with the virus, they had not found the virus in wild-caught mosquitoes—until now.
“This could have major repercussions here in the United States and in other parts of the world,” said Leal, a distinguished professor in the UC Davis Department of Molecular and Cellular Biology who is co-chairing the International Congress of Entomology meeting Sept. 25-30 in Orlando, Fla. The conference is expected to draw some 7000 entomologists throughout the world.
Leal said more work needs to be done to see if Culex mosquitoes are playing a role in the current epidemic. In an interview July 21 with health reporter Jennifer Yang of the Toronto Star, Canada's largest daily, he commented: “It looks like there were more vectors than we thought, and this is one of them. We don't have to panic, but we have to know. And now that we know, we have to take care of the Culex.”
A. aegypti is already established in California; it has spread to at least seven counties since its discovery in Clovis, Fresno County, in June 2013, according to medical entomologist Anthony Cornel of the UC Davis Department of Entomology and Nematology and the UC Kearney Agricultural Research and Extension Center, Parlier.
The Zika virus, which can result in birth defects in pregnancy, can be transmitted through exposure to infected blood or sexual contact. The Centers for Disease Control estimates that between 400,000 and 1.3 million cases have been discovered across South, Central, and North America, where the disease was previously unknown.
Leal and a group of 18 students just hosted a Zika Public Awareness Symposium on May 26 at Giedt Hall, UC Davis campus. The podcast can be accessed at https://video.ucdavis.edu/media/Zika+Virus+Public+Awareness+Symposium/0_n3aupf5c
Have you heard about the entomologist who went from researching venomous scorpions to alleviating human neuropathic pain?
That would be Bora Inceoglu, who holds a doctorate in entomology from the University of California, Davis. He and five colleagues were recently informed that their groundbreaking research on neuropathic pain made Discover magazine's Top 100 Science Stories of 2015. In fact, the research ranks among the Top 15 in the Medicine/Genetics category.
The Proceedings of the National Academy of Sciences published the UC Davis research, “Endoplasmic Reticulum Stress in the Peripheral Nervous System is a Significant Driver of Neuropathic Pain,” in July 2015. (See UC Davis news story)
Inceoglu, a researcher in the Bruce Hammock lab, UC Davis Department of Entomology and Nematology/UC Davis Comprehensive Cancer Center, and Ahmed Bettaieb, then of the Fawaz Haj lab, Department of Nutrition, served as the lead researchers. The six-member team, in addition to Inceoglu, Bettaieb, Haj, and Hammock, included K.S. Lee and Carlos Trindade da Silva, both of the Department of Entomology and Nematology/UC Davis Comprehensive Cancer Center.
They pinpointed the key mechanism that causes neuropathic pain--a complex, chronic and difficult-to-treat pain caused by nerve injuries from trauma or from such diseases as diabetes, shingles, multiple sclerosis and stroke.
Discover magazine headlined its story on the UC Davis research: “A Key Piece of the Pain Puzzle Is Solved.” Writer Heather Stringer quoted Hammock as saying: “Medications have historically focused on turning down the nerve response to pain, but now we've found one way to block the stress signal that generates the pain.
“Most of us probably take for granted that physical pain—whether it be from a sports injury, a kidney stone or appendicitis—can be attributed to some form of inflammation and that it will end,” Stringer wrote.
“Neuropathic pain, however, affords its sufferers no such luxuries,” Stringer pointed out. “It's chronic and unrelenting, and its cause is unknown, making treatment difficult. It turns out that neuropathic pain is triggered when the body experiences endoplasmic reticulum (ER) stress, a condition in which the production and transport of protein exceeds the cells' capacities, say researchers from the University of California, Davis. Because diabetics are at high risk of having neuropathic pain, the team studied diabetic rats that had neuropathic symptoms: hypersensitivity to touch and lack of heat sensation. And the rats' nerve cells showed clear signs of ER stress.”
“When the researchers treated the rats with a compound that blocks ER stress, the pain symptoms disappeared. Conversely, healthy rats developed neuropathy when they received chemicals that induce the stress response.”
How It All Began
Hammock discovered a human enzyme termed sEH which regulates a new class of natural chemical mediators. He and his lab then developed inhibitors of the sEH enzyme which degrades natural mediators reducing hypertension, inflammation and pain.
Recently he founded the company, Eicosis LLC, to target diabetic neuropathic pain. The company just received two large federal grants for translational drug development and aims to move one of the sEH inhibitors to human clinical trials.
Hammock, who holds a doctorate in entomology/toxicology from UC Berkeley in 1973, joined the UC Davis entomology faculty in 1980. He is a member of the National Academy of Sciences and a fellow of the National Academy of Inventors. The Hammock lab is the 30-year home of the UC Davis/NIEHS Superfund Research and Training Program, an interdisciplinary program funded by the National Institute of Environmental Sciences (NIEHS) that has brought in almost $60 million to the UC Davis campus. The Hammock lab is also the home of the NIH Training Grant in Biomolecular Technology. The lab alumni, totaling more than 100 graduates, hold positions of distinction in academia, industry and government as well as over 300 postdoctorates.
From Insects to Humans
How did Bora Inceoglu move from entomology to neuropathic pain?
"As most kids I found insect fascinating from the start, little machines that could do so much," he said. "As an undergraduate, I studied plant protection. Half of the curriculum was basic and applied entomology, the other half being plant pathology and weed science. Therefore, my college degree was mostly based on pest management and I found insecticide resistance most interesting. This was the impetus for seeking an advanced degree in this area."
Inceoglu was awarded two separate scholarships to study insecticide resistance in the U.S. His research of prominent laboratories in this area landed him in the Hammock laboratory in 1996. "Bruce was my major professor and I completed my Ph.D. in his laboratory in 2002," Inceoglu said. "My thesis was isolation and characterization of insect selective toxins from the venom of scorpions and Dr. Hammock had just received a sizable sample of venom of a South African scorpion, well known for its highly toxic properties. The insect selective toxins were highly sought after at the time because Dr. Hammock developed the technology to engineer these small peptides into the genome of an insect selective virus, a baculovirus. The genetically modified baculoviruses are much faster in killing the pest insects owing to the toxin being produced as the virus infects the host larvae and replicates within."
"Although unexpected, when I started characterizing the new venom we had, we found no insect selective peptide toxins in it," Inceoglou recalled. "Instead we identified a whole new class of peptides that affect mammalian ion channels." To make his work easier, he tried and obtained the live scorpion specimens imported from South Africa. "I do not think they are available for sale now but at the time I was able to get together a few dozens of these animals. I periodically milked the venom from these scorpions which enabled me to have a consistent supply of venom. "
"Currently we are not working on scorpion venoms," Inceoglu says, "but the technology developed by Dr. Hammock remains as one of the more innovative approaches to pest control."
Meanwhile, neuropathic pain research emanating from UC Davis continues to be spotlighted, as well it should be. It affects some 100 million Americans alone, but even more worldwide.
- Discover Magazine 100 Top Stories of 2015
- Discover Magazine: Key Piece of the Pain Puzzle Is Solved
- PNAS article
- UC Davis News Story: Groundbreaking Research on Neuropathic Pain
- Faculty 1000 Honor
When you're chasing a tiger, you don't have to worry about the fangs or the claws.
No worries about this tiger. This tiger has wings.
If you head over to the Storer Garden at the UC Davis Arboretum, you'll see plenty of tigers, Western tiger swallowtail, on the dwarf plumbago, Ceratostigma plumbaginoides. The plumbago is an Arboretum All-Star. (The UC Davis Arboretum horticultural staff has singled out 100 tough, reliable plants as All-Stars; that is, they're "easy to grow, don't need a lot of water, have few problems with pests or diseases, and have outstanding qualities in the garden. Many of them are California native plants and support native birds and insects. Most All-Star plants can be successfully planted and grown throughout California.")
The Western tiger swallowtail (Papilio rutulus) probably would consider the plumbago an All-Star, too, as it flutters around, sipping nectar and looking for a mate.
If you're lucky, you might be able to capture an image of the tiger next to the dwarf plumbago sign. Or, if you're really lucky, you might get two butterflies in one photo.
The Western tiger swallowtail is the kind of butterfly that takes your breath away; you tend to hold your breath while you're trying to hold onto a view of the tiger. It's a bit of flying sunshine in days darkened with trouble and turmoil.
Butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology, writes this about the tiger on his website (he's been monitoring the butterfly populations of Central California for more than 40 years): "The Western Tiger Swallowtail is basically a species of riparian forest, where it glides majestically back and forth along the watercourse. It has expanded into older urban neighborhoods where several of its host genera are grown as shade trees, and behaves as if the street were a watercourse. In the high country and on the Sierran east slope its usual host is Aspen."
Shapiro says the tiger "visits Yerba Santa, California Buckeye, Milkweed, Dogbane, Lilies, Coyotemint" and frequents gardens for Lilac and Buddleia. "Spring individuals are smaller and usually paler than summer. Low-elevation hosts include Sycamore (Platanus), Ash (Fraxinus), Cherry and other stone fruits (Prunus), Willow (Salix), Privet (Ligustrum), Lilac (Syringa) and (in Sacramento County) Sweet Gum (Liquidambar)."
On our block, we've seen the tiger flying around the sycamore and sweet gum. It then flutters over to our pollinator garden to sip nectar from the Buddleia (butterfly bush), Tithonia (Mexican sunflower) and Lantana.
This tiger has wings!
"You can hawk and perch in our yard all day if you want," I told her.
And she did.
A spotted dragonfly chose a spot in our pollinator garden--a bamboo stake overlooking a patch of Verbena and African blue basil--and she stayed most of the day.
At first I mistook the insect for the twelve-spotted dragonfly, Libellula pulchella. All I could see were spots! Bohart Museum of Entomology associate Greg Kareofelas of Davis who studies and photographs dragonflies and butterflies and other insects, identified it as a female whitetail, Plathemis lydia.
Plathemis lydia? It's a common dragonfly found across much of North America, according to Wikipedia. "The male's chunky white body (about 5 cm long), combined with the brownish-black bands on its otherwise translucent wings, give it a checkered look. Females have a brown body and a different pattern of wing spots, closely resembling that of female Libellula pulchella, the twelve-spotted skimmer. Whitetail females can be distinguished by their smaller size, shorter bodies, and white zigzag abdominal stripes; the abdominal stripes of L. puchella are straight and yellow."
"The common whitetail can be seen hawking for mosquitoes and other small flying insects over ponds, marshes, and slow-moving rivers in most regions except the higher mountain regions," according to Wikipedia. "Periods of activity vary between regions; for example in California, the adults are active from April to September."
This one was hawking and perching within several yards of our fish pond, as honey bees, carpenter bees, long-horned digger bees, European wool carder bees, Gulf Fritillaries and monarchs staked out their own territory.
I thought Ms. Libellula pulchella would move as soon as I approached her, but she held her ground--or stake. Occasionally, she'd leave to grab a meal and then return to her perch.
Another dragonfly circled but didn't land. I was hoping for a male, the one with the chunky white abdomen...
(Note: The Bohart Museum of Entomology offers a "Dragonflies of California" poster, featuring 18 images of dragonflies, in its gift shop at 1124 Academic Surge, Crocker Lane, UC Davis. The posters are the work of Bohart associates Greg Kareofelas and entomologist Fran Keller, who received her doctorate in entomology at UC Davis.)
So here's this tattered old worker bee seeking some nectar from the broadleaf milkweed, Asclepias speciosa. She looks as if she's not only been around the block a few times but around the county several dozen times. Her wings look too ragged to support her flight back to her colony. She'll probably live just a few more days. Worker bees live only four to six weeks in the peak season, and this is the peak season.
She bends her head and sips nectar, only to realize she is not alone. She encounters long antennae...the long antennae of a monarch caterpillar munching on a blossom. Whose plant is this? The bee wants the nectar. The monarch caterpillar wants the entire plant. This is the larval host plant of the monarch butterfly, Danaus plexippus. The caterpillars turn into veritable eating machines, devouring the leaves, flowers and some of the stems. Without milkweed, no monarchs. It's a matter of survival.
The tattered old bee touches antennae with the hungry caterpillar--Well, hello, there, dining companion!--and she backs off. There will be another blossom--if she moves quickly to claim it.
Another bee, this one much younger than the senior citizen bee, buzzes over to nearby blossom while another caterpillar, partially hidden, munches away. The bee gets stuck in the sticky mass of gold pollinia and struggles to free herself, just as another bee flies off with some of that gooey "winged" substance, anchoring her flight. She will remove it. She will return. The nectar is too enticing.
Just another chapter in the Saga of the Milkweed, the Bee and the Caterpillar...