World renowned artist to headline Ortiz/Labriola Lecture

February 17, 2014

World renowned Edgar Heap of Birds will headline the annual Simon Ortiz and Labriola Center Lecture on Indigenous Land, Culture, and Community at the Heard Museum at 7 p.m., Thursday, March 20.

ASU News spoke with him about his inspiration and ground-breaking work. headshot of artist Edgar Heap of Birds Download Full Image

What first attracted you to the arts?

I was attracted to arts as a young child via drawing – to make up what I wondered about: cars, airplanes, I guess boy stuff. Kiowa/Comanche artist Blackbear Bosin was a huge influence for me growing up in Wichita, Kan., during my teen years. He made art about Native life and was a popular figure locally. He mainly showed me that a native person could live and work as an artist. His subject matter was not very challenging, but to be a contemporary artist was a true challenge in America at that time, for an Indian. Later in graduate school, I was heavily influenced by New York City performance artist Vito Acconci.

You use a variety of mediums to express your art. Which one is your favorite?

I choose to work in many mediums because it serves the multiple parts of my existence. As humans, we are all complex people, but modern life and also the “Master Work” model for the artist (based on a classic Euro model) limits us to one form of job or art image. As I move through my diverse forms of art making, I can express myself better. It is hard to pick my favorite, but I guess the use of three-word phrases done in mono print is quick from my mind, and is realized in an almost mystical print medium. The three-word phrases are reminiscent of the new wave band “Talking Heads” and David Byrne, in particular. I was in grad school near New York City during the late 1970s, and their music and lyrics were in the flow then.

Where does your inspiration come from?

My inspiration comes from love of our indigenous lands and seas throughout the earth and its indigenous peoples and communities. I work globally, from Zimbabwe to Australia and Bali to Oklahoma, Europe and beyond. With these priorities then, one comes to the political issues which most are pronounced in order to protect the peoples, lands and seas. Thus, the inspiration also becomes subject.

How does your Native American heritage influence your work?

The main way my Native heritage influences my work is to always bear in mind a sense of reciprocity and grace.

What can the audience expect from your presentation at the Ortiz/Labriola Lecture?

For the Ortiz lecture, I will offer a traditional beginning of how Native women carry our past and future, and how as artists we work to protect what they are given. I will share many collaborative art projects from throughout the world, and also share my four or so specific art practices, including painting, public art, glass blowing, sculpture, printmaking and drawing. In addition to the PowerPoint talk, I will present short videos concerning recent art projects from Venice, London and Los Angeles.

What can we expect to see in the future from you as an artist?

At this time, I am painting newer versions of my “Neuf Series” paintings that come from time spent walking in the western Oklahoma landscape. I plan to offer more time to my painting in order for the practice to have a deeper development. I also plan to extend my public art projects, now begun in the Cheyenne and Arapaho reservation community halls. These 8- by 16-feet digital murals honor tribal elder artists from our sacred communities.

To learn more about the lecture, please visit the ASU Events calendar.

ASU Sponsors: American Indian Policy Institute; American Indian Studies Program; Department of English and School of Historical, Philosophical, and Religious Studies, both in the College of Liberal Arts and Sciences; Indian Legal Program in the Sandra Day O'Connor College of Law; Labriola National American Indian Data Center; School of Art in the Herberger Institute for Design and the Arts; Women and Gender Studies in the School of Social Transformation

Of mice and men: fine-tuning salmonella-based vaccines

February 17, 2014

An innovative vaccine technology makes use of reengineered salmonella to deliver protective immunity. If such recombinant attenuated salmonella vaccines, or RASVs, can be perfected, they hold the promise of safe, low-cost, orally-administered defenses against viral, bacterial, fungal and parasitic infections.

In a new study, lead author Karen Brenneman and her colleagues at ASU's Biodesign Institute propose an improved method of screening salmonella vaccines in small animal studies and enhancing their effectiveness in humans. Salmonella Download Full Image

The new research demonstrates a system for improving the ability of salmonella vaccine strains to survive the hostile environment of the stomach, where high acid concentrations are typically lethal for invasive bacteria. The data show a tenfold improvement in salmonella survivability in a mouse model, modified to mimic stomach acid conditions in humans.

The research team – which included Crystal Willingham, Jacquelyn A. Kilbourne, Kenneth Roland and Roy Curtiss III (director of Biodesign’s Center for Infectious Diseases and Vaccinology and Professor in ASU's School of Life Sciences) – recently reported their results in the journal PLOS ONE.

“Over the years, the mouse model has taught us a lot about how Salmonella interacts with mammalian hosts.  However, it turns out that the mouse model fails to provide relevant information on how Salmonella is able to deal with the extremely low pH of the human stomach,” says Roland, corresponding author of the new study.

An RASV vaccine uses salmonella – causative agent of gastrointestinal disorders, including common food poisoning. Researchers in the Curtiss lab have been modifying salmonella by removing virulence factors that cause illness, and outfitting the bacterium with key antigens associated with the vaccine disease target.

Salmonella-based vaccines are capable of powerfully stimulating mucosal, humoral and cellular immunity against invasive pathogens, but to be effective, the vaccine cargo ships – the salmonella – must survive hostile conditions of the stomach.

While RASV results in mice have been encouraging, human trials have proven less favorable. The authors speculate that the high acid (low pH) conditions of human stomachs compared with mice may be partly responsible for the discrepancy.

Many types of salmonella exist, and the form affecting humans – Salmonella enterica serotype Typhi – is species-specific. To test RASV vaccines in vivo, prior to human clinical trials, requires the use of Salmonella Typhimurium, a closely related strain affecting mice and producing an illness similar to human typhoid.

One critical area in which mice differ from humans however, is in the acidity of their stomachs. For humans, the pH level in an empty stomach is between 1.0 and 3.0, whereas for mice, it is around 4.0.

“Finding a way to temporarily lower the stomach pH of a mouse sets the stage for further research into designing more effective oral vaccines, such as RASVs, and will provide new insights into how wild-type pathogenic bacteria survive this barrier. Our paper also demonstrates the utility of our previously described, novel acid-resistance systems to increase survival of RASVs in vivo at low pH,” Roland says.

In the new study, high acid conditions in the mouse stomach were transiently induced through the injection of histamine. The histamine mouse model was capable of distinguishing Salmonella strains showing acid sensitivity or acid resistance, previously identified under laboratory conditions. The observed results in histamine mice were shown to closely correlate with in vitro acid resistance or sensitivity.

Low gastric pH is common to many host species, including humans, and acts in part as a defense mechanism to kill the majority of ingested microbes. The microbes, however, have actively developed strategies to attempt to survive such conditions, in a kind of evolutionary arms race.

Some microbes fare better than others under low pH, however. S. Typhi – the salmonella strain used for RASVs – is normally rather intolerant of low pH conditions, compared with the S. Typhimurium strains tested in mice.

A further factor of critical importance is the difference in gastric biology between mice in humans. Prior to RASV vaccine administration, both mice and humans are usually fasted in order to empty the upper part of the gastrointestinal tract. In mice, this has the effect of raising pH from around 3.0 to 4.0. In humans however, fasting pH is lowered, falling below 2.0. As the authors note, the mouse stomach after fasting poses only a mild challenge to the RASV invasive bacteria, whereas in the human stomach, conditions are hostile enough to kill most vaccine cells, undermining effectiveness.

Bacterial cells used for RASVs are generally not cultured for acid resistance, and are therefore particularly vulnerable to high acid gastric environments, further hampering their effectiveness. One common method for getting around the vulnerability of vaccine cells is to administer them in conjunction with an antacid or other agent designed to protect from low pH. The technique improves survivability – but at a cost. Without exposure to low pH, the salmonella vaccine bacteria lose valuable positional signals that help them colonize the intestine and successfully invade host tissue.

In the current study, heightened resistance to stomach acid was conferred to RASV strains through a special system using rhamnose-regulated arginine decarboxylase. The system was shown to dramatically increase survival of acid-sensitive S. Typhi in vitro at a pH of 2.5.

The researchers next sought to examine the effectiveness of RASVs containing the new acid resistance system in vivo, under the low pH conditions induced in the histamine mouse model. Results showed a tenfold improvement in the ability of these modified strains to survive a gastric pH of 1.5 in the mouse stomach, and to successfully reach the intestinal tract. The implication is that such modified vaccine strains will likewise survive similar low pH conditions in humans, dramatically improving their effectiveness.

The study findings suggest that the histamine mouse model may be a useful tool for evaluating not only RASV candidates, but any orally administered microbial treatment (for example, pro-biotic bacteria). For microbes displaying acid sensitivity, the rhamnose-regulated arginine decarboxylase acid-resistance system can improve survivability under low pH and successful transit to the intestinal tract. Such improvement may elevate vaccine effectiveness while allowing a reduction in dose.

Richard Harth

Science writer, Biodesign Institute at ASU