Naoki Yamanaka, an assistant professor at UC Riverside (UCR), is known for his innovative and creative research. In fact, the National Institute of Health (NIH) just awarded him a $2.4 million grant in its High-Risk, High-Reward Research Program to study the role of steroid hormone transporters in insect development and reproduction. A UCR news release pointed out that he will "translate that knowledge into new ways to combat the spread of mosquitoes, which are among the deadliest animals on the plant."
Fast forward to today--actually next week! And this time, it's about fruit flies. Steroid hormone transporters in fruit flies.
Yamanaka will discuss "A Membrane Transporter Is Required for Steroid Hormone Intake in Drosophila" at the UC Davis Department of Entomology and Nematology seminar, set from 4:10 to 5 p.m., Wednesday, Oct. 24, in 122 Briggs Hall. Host is seminar coordinator and medical entomologist Geoffrey Attardo, assistant professor of entomology.
"Steroid hormones are a group of lipophilic hormones that are believed to enter cells by simple diffusion to regulate diverse physiological processes through intracellular nuclear receptors," Yamanaka explains. "We recently challenged this model in the fruit fly Drosophila melanogaster by demonstrating that a membrane transporter that we named Ecdysone importer (Ecl) is involved in cellular uptake of the steroid hormone ecdysone.Eci encodes an organic anion transporting polypeptide of the evolutionary conserved solute carrier organic anion superfamily. Results of our study may have wide implications for basic and medical aspects of steroid hormone research."
Yamanaka, who received his doctorate in biological sciences in 2007 from the University of Tokyo, says that his lab is "focused on identifying and characterizing neuroendocrine signaling pathways that regulate physiological and behavioral changes during insect development. Similar to humans, where physical and mental development during juvenile stage (puberty) is controlled by the neuroendocrine system, insects also have a sophisticated hormone signaling network that regulates their developmental transitions. Mainly by using fruit fly molecular genetic tools, we would like to understand what kind of hormones and receptors are involved in this system, how they work at the molecular level, and how such knowledge can be applied to develop new approaches to control animal development."
This is exciting research.
What exactly are "steroid hormones?" As author Sarah Nightingale explained in the UCR news release:
"Steroid hormones mediate many biological processes, including growth and development in insects, and sexual maturation, immunity and cancer progression in humans. After they are produced by glands of the endocrine system, steroid hormones must enter cells to exert their biological effects. For decades, the assumption has been that these hormones enter cells by simple diffusion, but preliminary work in Yamanaka's lab suggests a defined passageway controlled by proteins called membrane transporters."
Said Yamanaka: "The overall goal of this project is to challenge the conventional paradigm in endocrinology that steroid hormones freely travel across cell membranes by simple diffusion. We will also screen chemicals that inhibit steroid hormone entry into cells, with the goal of developing new pest control reagents.”
The NIH High-Risk, High-Reward Research Program is quite competitive. This year NIH officials granted only 89 awards and they were to “extraordinarily creative scientists proposing highly innovative research to address major challenges in biomedical research.”
Yamanaka's research may lead to important pest control strategies for mosquitoes that transmit deadly diseases. As Nightingale explained: "Using the simple but powerful fruit fly model, his team will study how the insect steroid hormone ecdysone is transported in (and potentially out) of cells with the help of membrane transporters. Since ecdysone controls metamorphosis and molting as an insect moves from one stage of its life cycle to the next, blocking its transport could offer a new way to inhibit insect growth and development. The team will then study the same transport pathway in the mosquito that causes yellow fever, hoping to identify chemicals that inhibit steroid hormone transport as a pest control strategy. Worldwide, mosquito-borne diseases cause millions of deaths each year, with malaria alone causing more than 400,000 deaths, according to the World Health Organization."
Bottom line: “By targeting the membrane transporter from outside the cells, we may be able to circumvent common pesticide resistance machinery provided by proteins within the cells, such as detoxification enzymes and drug efflux pumps,” Yamanaka pointed out in the news release.
His seminar at UC Davis is the fifth in a series of fall seminars coordinated by Attardo. (Note: The Yamanaka seminar will not be recorded.)
Upcoming seminars include:
4:10 p.m., Wednesday, Oct. 31
Fred Wolf, assistant professor, UC Merced: (tentative title) "Drunken Drosophila and the Coding of Brain Plasticity"
Host: Joanna Chiu, associate professor and vice chair, UC Davis Department of Entomology and Nematology
4:10 p.m., Wednesday, Nov. 7
Lark Coffey, assistant professor in the Department of Pathology, Microbiology and Immunology, UC Davis School of Veterinary Medicine: "Zika Virus in Macaques, Mice and Mosquitoes: Contrasting Virulence and Transmissibility in Disparate Hosts"
Host: Geoffrey Attardo
So you're walking along Doran Regional Park Beach in Sonoma County on Tuesday, Oct. 16 and thinking about the pollinators in your back yard. (Don't we all?)
And then: what a delight to see. Apis mellifera (honey bees) and Eristalis tenax, syrphid flies (better known as a "drone flies") nectaring on the tiny blossoms of a sea rocket plant (genus Cakile).
This particular plant species? The European sea rocket, Cakile maritima, a succulent annual that's a member of the mustard family. It grows in clumps or mounds on sandy beaches and bluffs along the coastlines of North Africa, western Asia, and North America. It boasts a long, slender and stout taproot.
You've probably seen it. But you may not have noticed the pollinators.
"Their leaves are fleshy," is how Wikipedia describes the plant. "Flowers are typically pale mauve to white, with petals about 1 cm in length. Each fruit has two sections, one that remains attached to the adult, and the other which that falls off for dispersal by wind or water."
At Doran Beach, two species of sea rocket (C. maritima or European sea rocket, and C. edentula or American sea rocket) bloom from spring through summer--and sometimes in early fall.
Bees at the beach? Floating fruit?
And flies (syrphids), too.
It starts out slow.
Beginning in the spring (and sometimes year-around in some locales) Gulf Fritillaries (Agraulis vanillae) lay their eggs on their host plant, the passionflower vine (Passiflora).
They deposit their eggs on the tendrils, on the leaves, and sometimes on the fence, wall or door where the passionflower vine climbs.
When fall approaches and the Gulf Frits are still laying eggs, you won't recognize your vine. It is skeletonized. The caterpillars, incredible shredding machines, have devoured all the leaves, leaving nothing but scarred sticks. And the 'cats are now gobbling up the remaining fruit. Hungry, hungry caterpillars!
Your plant, now incognito, looks like it should be in the Federal Witness Protection Program--and you have to defend yourself for "being a bad gardener."
But that's why we plant the Passiflora: for the Gulf Frits.
"No plant wants to be eaten," wisely observes Bruce Hammock, a UC Davis distinguished professor with a joint appointment in the Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center. "They all have defenses. They do not like insects, fungi, cows or even vegetarians that eat them."
At the time, Professor Hammock was talking to a reporter about toxic plants, and how we have bred many poisons out of plants or learned to not eat the most toxic parts. "In some cases, we like the taste of the poisons: cinnamon, potato, parsley, and mustard," Hammock told him.
In the case of the passionflower vine, aka Scraped Skinny Stick, it probably wishes (if plants could wish) and wonders (if plants could wonder) "Why am I so attractive?" and "Where are all the birds, wasps and other predators of caterpillars when I need them?"
They don't announce their arrival or departure.
If you're an insect photographer, or a wanna-be-insect photographer, expect the unexpected and don't go anywhere without your camera.
That applies to such simple things as walking out your back door and stepping into your pollinator garden.
It was Friday morning, Oct. 12, and we watched a gust of wind stir the African blue basil, tousle the milkweed, and whip the 12-foot-high Mexican sunflower. "Ah, wind," I thought. "A good day for dragonflies."
As if on cue, a variegated meadowhawk dragonfly, Sympetrum corruptum, touched down on a bamboo stake, and looked right at me. I edged closer and "she" (gender identified by naturalist Greg Kareofelas, an associate with the Bohart Museum of Entomology, University of California, Davis) quickly left her perch.
I figured she would return and she did. Camera already raised, I slowly pointed my Nikon D800 with the 200mm macro lens and pressed the shutter. She left. She returned. She left. She returned.
A 'portrait studio' with the subject giving me "yes-no-maybe" answers.
In one view below, you can see the “bi-colored” Pterostigma on the wing tip and the two black spots on the top of the tip of the abdomen," noted Kareofelas. "This is unique to this species."
In another view, you can see the blurred image of a Mexican sunflower (Tithonia) forming a backdrop.
Insect photography takes patience, persistence and perseverance because these six-legged critters don't announce their arrival or their departure, not like at an airport or a train station.
But they are there. "At any time, it is estimated that there are some 10 quintillion (10,000,000,000,000,000,000) individual insects alive," according to the Smithsonian Institute. That's about 200 million insects for every human on the planet.
Your camera will find at least one of them at any given time of day.
But they're not welcome.
Agriculturists who commercially grow cabbage and other cucurbits aren't fond of the cabbage white butterlfy, Pieris rapae, because its larvae are pests that ravish their crops.
No welcome mat for them.
This butterfly, however, is welcome--sort of--starting Jan. 1 of every year in the three-county area of Sacramento, Solano and Yolo. It's the target of the "Beer for a Butterfly Contest," sponsored by Art Shapiro, UC Davis distinguished professor of evolution and ecology. The first one collected in the three-county area collects a pitcher of beer or its equivalent.
Professor Shapiro, who maintains a research website at http://butterfly.ucdavis.edu, launched the contest in 1972 as part of his long-term studies of butterfly life cycles and climate change. Pieris rapae is emerging earlier and earlier as the regional climate has warmed, he says. "The cabbage white is now emerging a week or so earlier on average than it did 30 years ago here."
He usually wins the suds-for-a-bug contest; he has been defeated only four times, and all by UC Davis graduate students. This year (2018) he collected the cabbage white butterfly, Pieris rapae, at 11:23 a.m. Friday, Jan. 19 in one of his frequented sites—a mustard patch by railroad tracks in West Sacramento, Yolo County. (See Bug Squad blog)
Last weekend we spotted a cabbage white nectaring on lantana, a common occurrence. What was not so common was that this one wasn't skittish. It lingered like a ballerina anticipating a curtain call, and allowed us to photograph it in flight.