Seminar Series Promotes the Exchange of Scientific Information: New Methods to Measure Toxins and Their Effects on Human Cells
On Monday, April 21st, the Superfund Research Programs at UC Davis (UCD) and the University of Arizona (UA) collaborated to showcase cell-based tools for environmental assessment in the seminar series titled: “New Research on Toxicity Screening Methods.” Dr. Scott Boitano (UA) described how he conducts Real Time Cell Analysis (RTCA) using the XCELLigence system, while Dr. Michael Denison explained his technology called the Chemically-Activated Luciferase Expression (CALUX) Bioassay. Both technologies are radically new means in which scientists can measure human cell responses after exposure to varying levels of environmental toxins.
The "Live at EPA Region 9" lecture series provides a platform for NIEHS Superfund Research Program (SRP) researchers to share their research findings with scientists in the Pacific Southwest (EPA Region IX). The lecture is presented at Region 9 headquarters in San Francisco to EPA staff and invited attendees, and is coordinated by Michael Gill, Superfund and Technology Liaison, in collaboration with UA and UCD Research Translation Core Leaders. Approximately one month after the live seminar at Region 9, the researchers will publically broadcast another live presentation via webinar through the EPA CLU-IN website (date: TBD; check the CLU-IN website for the most recent information).
L to R: Michael Gill (US EPA), Dr. Scott Boitano (UA SRP), Dr. Michael Denison (UCD SRP), and Dr. Candace Bever (UCD SRP Translation Coordinator)
In the interest of science: What can cells-based technologies do for environmental regulators?
For Dr. Scott Boitano, cell-based technologies help him examine dangers found in air pollution. At the cellular level, there already exist methods to detect cytotoxicity (cell death caused by toxins). Dr. Boitano uses RTCA, which provides a way to measure non-lethal changes in the cell when exposed to toxins. The ability to observe these phenomena is highly relevant for studies examining chronic, long-term environmental exposure of the air we breathe, as the levels of contaminants humans are exposed to on a daily basis may not cause immediate cell death but may affect other biological functions.
Dr. Boitano’s research focuses on the toxicity of inhaled engineered nanoparticles, metals, and metalloids on the epithelial lining of the respiratory tract and uses a human, immortal epithelial cell line in his RTCA assays. RTCA allows for taking time points in intervals as short as 30 seconds and for running the assay for as long as needed, three weeks in Dr. Boitano’s experiments. RTCA is a valuable tool for evaluating the toxicity of chronic, low-level toxin exposure from air pollution because it can detect cell signaling abnormalities that contribute to the negative health outcomes observed in humans.
Dr. Michael Denison, on the other hand, uses cell-based technologies to tell him if a common consumer product or an environmental sample contains toxins that interfere with natural biological functions, such as hormone regulation. His CALUX bioassays are designed to detect gene expression induced by chemicals that mimic endogenous ligands for specific receptors. By inserting the gene that produces the fluorescent compound in fireflies, luciferase, next to the genes that respond to these ligands, researchers can quantify the potency of a sample based on the fluorescence level expressed in the cell. Dr. Denison’s research has shown that CALUX bioassays can predict toxicity in animal studies more accurately than strictly analytical means because the results are based on whether the pathway is activated, not solely on the presence or absence of a particular chemical.
CALUX bioassays are more useful for analyzing unknown chemicals from the environment, which usually contain mixtures of chemicals. Using CALUX, Dr. Denison’s lab evaluated a range of everyday products for estrogenic activity. They found that all but one sunscreen brand of those sampled had estrogenic activity, and that children’s plastic cups and plates showed estrogenic activity. A particularly concerning finding showed that some of the plastics leached potent estrogenics into pure water without any heating or chemical treatment, with color-changing sippy cups as the worst offenders. Dr. Denison advocates for using the CALUX bioassay as a fast and inexpensive tool for screening new chemicals for their biological potency. It is estimated that new chemicals are introduced into commerce at a rate of 7 chemicals/day*!
Spreading the Word About Toxin Exposure: Superfund Research Highlighted at the Annual UC Davis Picnic Day
On April 12th, 2014, UC Davis celebrated its 100th Picnic Day, a celebration of its agricultural roots and of its premier research facilities and projects. The UC Davis Superfund Research Program (SRP) again took advantage of this tremendous opportunity to engage with the public and developed an exhibit to inform the public about their research and their mission. Graduate students Sean Kodani and Erika Fritsch, as well as Research Translation Core Leader Dr. Candace Bever and intern Allison Dycaico, led an exhibit which focused on how organisms accumulate toxins through the food chain via the ecological processes known as bioaccumulation and biomagnification. This year, the UCD SRP invited the Oregon State University (OSU) SRP to participate, which included Training Core Leader, Dr. Craig Marcus, and trainees Andrea Knecht and Erin Madeen. Alongside the UCD SRP exhibit about biomagnification and daily toxin exposure, the OSU SRP presented posters about their research on polycyclic aromatic hydrocarbons (PAHs) in smoked meat prepared by Native Americans and the effect of PAHs on development in zebrafish.
OSU SRP Trainees Andrea Knecht (left) and Erin Madeen (right) present posters about their research at the collaborative Superfund booth at Picnic Day.
Amid the vast crowds flocking to the ever-popular dachshund races, maggot painting exhibit, or cow milking tutorial, many stopped to check out the Davis SRP’s children’s game “Toxin Hunt” or to engage with the scientists about how to mitigate daily toxin exposure. As with previous years, the public was anxious to learn more about chemicals directly affecting their health. Dr. Marcus reported that adults seemed most drawn to the information on PAHs in smoked meat because of a universal truth: “people like food.”
Children experience biomagnification in a “Toxin Hunt” game
The UCD SRP “Toxin Hunt” provided an excellent platform to engage with the more than 125 children who played the game. The activity was designed to teach participants about biomagnification hands-on. First, participants personalized a headband depicting the animal of their choice: shrimp, fish, seal, or polar bear. Each animal could eat only certain colors of Easter eggs – representing different prey animals – depending on their trophic level in the food chain. For example, a shrimp could only eat algae (green), whereas a seal could eat algae (green), shrimp (yellow), and fish (blue). Unbeknownst to the participants, the Easter egg contained specific amounts of cotton balls to represent 'toxins'. After the participants collected as many eggs of the appropriate color as possible in ten seconds, they counted their total number of accumulated 'toxins' and plotted them on a graph. Dr. Bever was delighted with how this portion of the activity worked out, since it provided the participants with a sense of "being a scientist", demonstrating how we collect and interpret data.
UCD SRP Trainee Sean Kodani (right) helps a young “scientist” report her data on a graph.
The participants as a whole clearly understood the idea of biomagnification, leading some children to lament that they had chosen the more toxin-accumulating polar bear over the relatively clean shrimp, and some self-appointed shrimps to congratulate themselves on their wise decision. The children also seemed to have an intuitive grasp of how to depict data on a graph. Through integrating fun and creativity with education in “Toxin Hunt,” the UCD SRP team was able to convey an important message to both children and adults about how we are exposed to toxins through the food we eat.
UCD SRP Trainee Erika Fritsch (left) counts toxins with participants of all ages.
OSU SRP Trainees enjoy their first Picnic Day
Trainee Erin remarked that she was pleasantly surprised that the animal laboratories opened their doors to the public for Picnic Day, explaining that, “people have this strong, negative perception of animal research, and if they can see it in person and how it actually is, that will really influence public opinion and support for research.” Andrea and Erin celebrated their first Picnic Day by networking with the UCD SRP members and touring their labs. Both trainees are researching the health effects of PAHs. When asked which part of the event she enjoyed most, Andrea responded, “I’d have to say the dachshund races. Adorable!” The UCD SRP and OSU SRP found this outreach collaboration to be highly beneficial for both programs and have already discussed plans for future collaborative events.
SRP Trainee Webinar featuring Erika Fritsch from UC Davis and Chase Williams from U of Washington
This webinar series features the outstanding work being conducted by graduate student, Chase Williams and postdoctoral scholar, Erika Fritsch, conducting SRP-funded research. Specifically, this year's series consists of presentations from Poster Award Winners from the previous SRP Annual Meeting. This is an excellent opportunity for peers, SRP researchers, SRP alumni, and SRP's partners (NIEHS, U.S Environmental Protection Agency, and Agency for Toxic Substances and Disease Registry, etc.) to hear the poster winners describe their current research/activities. This will also be a chance for others to learn more about the research/activities being conducted by SRP trainees (i.e., graduate students/post-docs) and for those who were not able to view their posters at the Annual Meeting. Most importantly, the intent of the series is to increase collaboration and exchange of ideas among young investigators conducting SRP-funded research/activities and to hear about their award-winning work. The presentation titles and abstracts are below.
The webinar will be held on May 23rd, 2013 2:00 – 3:00 pm EDT. (Mark it on your calendar!)
Please register via the gotowebinar registration page.
Erika Fritsch: Non-coplanar PCBs and Ca2+ Signaling in Teleost Species: Addressing Comparative Mechanisms of Toxicity and Developed Resistance in New Bedford Harbor
To date risk assessment practices for polychlorinated biphenyls (PCBs) primarily focus on the impact of dioxin-like or so called coplanar congeners, especially in non-mammalian species. Non-coplanar PCBs (ncPCBs) lack dioxin like toxicity but have been found to enhance the activity of the ryanodine receptor (RyR) a Ca2+ release channel necessary for excitation-contraction coupling in cardiac and skeletal muscle. Thus far, these effects have only been addressed in mammals even though ncPCBs account for more than 50% of the documented PCB burdens in aquatic organism, namely fish species. Fritsch utilized in vitro assays to investigate the impact of commonly detected ncPCBs on RyR activity in rainbow trout (Oncorhynchus mykiss). Additionally, she investigated whether Atlantic killifish (Fundulus heteroclitus) inhabiting the heavily PCB contaminated New Bedford Harbor (NBH) have RyR related mechanisms of ncPCB resistance. She found that environmentally relevant ncPCBs, but not coplanar PCBs, enhance the activity of the RyR isoform 1 (RyR1) found in rainbow trout skeletal muscle. She also shows that in accordance with increased RyR1 related protein expression; RyR1 channels in NBH killifish display increased ligand binding, increased responses to Ca2+ sensitivity and increased maximal responses to channel disruption by the ncPCB congener 95. Additionally, NBH killifish had elevated protein levels of the FK-binding protein, known to play a role in ncPCB mediated toxicity at the RyR. These findings further the understanding of PCB induced altercations at the RyR by exploring common mechanisms of action across vertebrate species and describing population susceptibility in an effort to protect human and wildlife health.
Chase Williams: Effects of Cadmium on Olfactory Mediated Behaviors and Molecular Biomarkers in Coho Salmon (Oncorhynchus kisutch)
Salmon populations have declined in the western United States, with several species being listed as extinct or endangered. One factor implicated in these population declines is inhibition of olfactory processes associated with exposures to waterborne pollutants, including metals such as copper and cadmium. Cadmium (Cd) represents an EPA priority compound but remains relatively under studied in regards to olfactory toxicity in salmonids. In the current study, Williams analyzed olfactory-mediated alarm responses, epithelial injury and recovery, and a suite of olfactory molecular biomarkers encoding genes critical in maintaining olfactory function in juvenile coho salmon receiving acute exposures to Cd. The molecular biomarkers analyzed included four G-protein coupled receptors (GPCRs) representing the two major classes of odorant receptors, as well as markers of antioxidant responses to metals. Coho received acute exposures to 3.7 ppb and 347 ppb Cd, and a subset of fish was analyzed following a 16-day depuration. The results indicate that acute Cd exposures can have rapid and persistent effects on olfactory neurobehavioral function. Similar behavioral effects have been linked to impaired survival and increased susceptibility to predation in salmonids. Williams’ approach involving molecular biomarkers, histological analysis, and behavior suggested that impairment of key olfactory sensory neurons (OSNs) and GPCRs may underlie impaired alarm responses. In the context of biomonitoring for olfactory injury in the field, the molecular biomarkers of oxidative stress may be of particular relevance in reflecting metal exposures and the ability of fish olfactory tissues to mount an antioxidant response within the olfactory epithelium.
Dr. Pamela Ronald discusses role of GMOs in ecological farming
Friday night (May 3rd), UC Davis' Superfund Research Program and the UC Davis Genome Center co-sponsored a “Science and You - Informational Talk” (SAY-IT) forum featuring plant pathologist Dr. Pamela Ronald. SAY-IT is a series of free lectures, hosted quarterly at the Pence Gallery in downtown Davis, where UC Davis scientists share research findings and initiate dialogue with the general public.
Ronald (top right corner) engages a very interested community in Davis, CA in a discussion about GMOs.
Ronald’s talk covered the spectrum of methods to developing genetically improved crops - from conventional breeding to genetic engineering. She pointed out that virtually everything we eat has been genetically altered in some way. Very few of the foods we eat (with the exception of line-caught salmon caught off the Farallon islands or wild mushrooms gathered in the coastal range) exist outside of farms. Every new crop variety, whether it is the product of GE or conventional breeding must be evaluated on a case by case basis. Each must be evaluated in light of the economic, environmental and social benefits, the three pillars of sustainable agriculture.
Ronald provided several examples, such as virus resistant papaya, that is resistant to a devastating virus and insect tolerant cotton, which reduced the use of sprayed insecticides in Arizona, India and China. In Bangladesh, rice crops genetically altered through precision breeding to withstand frequent flooding retain three times the yield of unmodified rice. For families living on less than a dollar a day, that makes a world of difference.
Ronald also addressed many stigmas associated with genetic engineering as she opened the floor to questions and people voiced their concerns about tweaking crop genes. The stigma, Ronald believes, stems from preconceived notions and limited insight on the technology’s transformative effect in developing countries.
“Today, genetic engineering is still fraught with politics,” said Ronald. “As with climate change, we see the same kind of schism in GMO debates. There’s often a split between accepted scientific consensus and the general public.”
Attendees of the SAY-IT public lecture series mull over the presentation while enjoying light refreshments at the Pence Gallery in downtown Davis.
Motivated to find out more
After the lecture, the group headed downstairs for refreshments, where the conversation continued. Many attendants, like Maria Cabrera, who works with immigrant students at Pioneer Elementary, expressed gratitude for the event because it broadened their perspectives on the subject.
“I was very impressed by the dramatic time-lapse video comparing the yields of regular and genetically modified rice after a flood,” said Cabrera. “Hearing this talk made me want to do more research looking into the risks and benefits of genetic engineering.”
Organic-favoring communities, like Davis, sometimes hold negative slants on genetic engineering. But Ronald’s talk underscored the global agricultural progress it fosters.
“The talk was wonderful and informative,” said Carolyn Munch, a retired dental hygienist. “I came in pretty skeptical about genetic engineering, but the talk gave me another look at GMOs that I hadn’t heard of before.”
While genetic engineering is a scientific endeavor, Ronald stresses that public support is just as important. Through venues like SAY-IT, people from a wide range of backgrounds— from scientists at the lab bench to consumers at the farmer’s market—can pool their expertise and come to the table to further examine the science. In the end, says Ronald, “We want everyone at the table.”
Superfund provide a science demonstration for a local elementary school
Davis, CA basked in the ripe heat of spring this Picnic Day as thousands flocked to the 99th annual gala of cow milking, cockroach racing, and pitbull kissing. Tucked in the air-conditioned cool of Meyer Hall, UC Davis' Superfund Research Program (SRP) engaged Picnic Day attendees with a different kind of exhibit—one that left them better-informed of household toxins.
SRP’s interactive “Hide and Seek” poster prompted visitors to find the hidden toxin (under flaps) and seek its respective solution (on the side panels). Since SRP investigates hazardous waste and its impact on human health, the poster aimed to inform audiences of everyday toxins that might be lurking in their homes. Pharmacology and Toxicology graduate students Sean Kodani and Lindsey Curley moderated the poster exhibit throughout the day.
“You kind of have to ring people into the conversation,” said Kodani. “But when you do, you get people from all different levels of knowledge interested in finding out more, because it’s so relevant to their lives.”
What are the hidden chemicals?
The topics of greatest concern among visitors—mostly parents with young children—were the effects of Teflon, lead, and flame retardants. Curley also noted that the hazards of an antibacterial chemical (triclosan) added to toothpaste and soap surprised many; in fact, most had never heard of the chemical. Triclosan fights bacteria, a common culprit of gum disease, but it’s also known to disrupt crucial hormone signals, as well as heart and muscle function.
At the exhibit, flyers reinforced the poster’s message and provided further resources for those concerned about toxin exposure. People especially appreciated the lead testing flyer, and many inquired about lead testing kits.
“The flyers helped because they weren’t just about ‘You shouldn’t do this, you shouldn’t buy that,’” said Kodani. “They gave people information on where to get their household items checked out, or where to find alternative solutions.”
April 2, 2013
In groundbreaking research, the team of 16 scientists led by Dr. Guodong Zhang of the Bruce Hammock laboratory, Department of Entomology and the UC Davis Comprehensive Cancer Center, discovered cytochrome P450 epoxygenase metabolites of omega-3 fatty acid DHA or epoxy docosapentaenoic acids (EDPs) block blood supply to the tumor and thus inhibit tumor growth and metastasis.
The natural EDPs were further stabilized by a drug called a soluble epoxide hydrolase inhibitor which is already under development to control pain and hypertension. The research is to be published the week of April 1-5 in the Proceedings for the National Academy of Sciences (PNAS). The studies, conducted on mice, also suggest that a combination of omega-3 diet and some anti-cancer drugs such as sorafenib.
Other co-authors of the paper in addition to Hammock were Jun Yang, Jun-Yan Liu, King Sing Stephen Lee, Arzu Ulu, and Sung Hee Hwang, all of the UC Davis Department of Entomology and UC Davis Comprehensive Cancer Center; Lisa Mahakian, Xiaowen Hu, Katherine Ferrara, Sarah Tam, and Elizabeth Ingham, UC Davis Department of Biomedical Engineering; Hiromi Wettersten of the UC Davis Division of Nephrology, Department of Internal Medicine; Robert Weiss, Comprehensive Cancer Center, Division of Nephrology and U.S. Department of Veterans’ Affairs Medical Center, Sacramento; and Dipak Panigrahy and Mark Kieran of the Vascular Biology Program, Children’s Hospital, Harvard Medical School.
UC Davis to test experimental drug for laminitis in horses
November 14, 2012
UC Davis Bioassay Adopted for EPA Screening Program
The UCD SRP Center Project that developed the assay, entitled “Development and Applications of Integrated In Vitro and Cell-Based Bioassays,” aims to develop and validate mechanistically-based cell and in vitro bioassays to screen for specific chemicals or chemical classes in environmental and biological samples.
Data generated from studies performed using the validated BG1Luc assay will be accepted in all 34 OECD member countries, including the United States. It will also satisfy the Estrogen Receptor Transcriptional Activation requirement of the EPA's Endocrine Disruptor Screening Program.