By Darla Martin Tucker

Like determined detectives, a La Sierra University biology professor and an undergraduate pre-medical student are bent on playing their part in helping defeat a health menace that plagues millions.

Dr. Lee Greer and student researcher Liao Tzu Yi, known as Janice Liao, are using recently acquired DNA sequencing equipment in Greer’s lab to tackle the job. Their mission: uncover population genetic data that may help better understand how to break the life cycle of a parasite that infects an estimated 200 million people in some 74 tropical countries with schistosomiasis, or snail fever. The parasitic infection causes anemia, bladder dysfunction, kidney and liver disease, and stunts physical and cognitive development in children.

Greer and Liao, together with other students in the lab, are working in conjunction with Dr. Grace Adeoye, a Seventh-day Adventist zoology
instructor at the University of Lagos, Nigeria. In June Adeoye provided the lab with a first set of vials of preserved parasites and their eggs. Adeoye ultimately connected with Greer after sending word through her son, who attended Loma Linda University in Loma Linda of her interest in working with U.S. researchers in battling schistosomiasis. Loma Linda University is a sister institution to La Sierra University. Another La Sierra scientist, Dr. John Perumal, heard of Adeoye’s proposed project and brought it up to Greer. “I said yes. It fits with everything we’re trying to do,” Greer said.

Greer’s DNA Sequencing and Genomics Lab (http://faculty.lasierra.edu/~lgreer), which he established this past school year, is dedicated to research that embraces humanitarian and ecological causes and at turning out top young scientists devoted to such work.

There are currently no vaccines for schistosomiasis. Only one drug, praziquantel, treats the infection. Due to limited manufacturing, few large-scale drug donations and funding constraints of humanitarian nonprofits, the medication is dispensed to a fraction of those infected. Essentially, schistosomiasis falls into the category of ailments scientists call neglected tropical diseases, or NTDs.

"The schistosomiasis research at La Sierra is very significant as very
little has been done on the molecular aspect of schistosomiasis in Nigeria,"
Adeoye said. "My research team at the University of Lagos is carrying out
epidemiological surveys of schistosomiasis in different parts of the country
among school aged children. We are also studying the snail intermediate
hosts for schistosomiasis. The parasite materials obtained during the
epidemiological surveys are sent to La Sierra University for molecular
analysis."

"It is hoped that as soon as funding is available, my Ph.D. student and
myself will go to La Sierra University to acquire the relevant molecular
skills," she said.

Schistosomiasis affects “an estimated 207 million of the bottom billion people who live on no money. It is neglected because it is exclusively a disease of the poor,” said Peter Hotez, president of the Albert B. Sabin Vaccine Institute in Washington D.C. Researchers there are working on a new recombinant vaccine to prevent schistosomiasis. Hotez is also chair of the Department of Microbiology, Immunology & Tropical Medicine at George Washington University, and editor-in-chief of PLoS Neglected Tropical Diseases journal.

“There [is] a dearth of researchers for schistosomiasis in the U.S. and the world. And there is great importance to identifying vulnerable spots in the parasite life cycle,” Hotez said.

Schistosomiasis is brought about by a parasite borne by a freshwater snail host that lives in lakes, ponds and other water sources. The parasite leaves the snail at an infectious larvae stage and burrows into humans through the skin when people swim and wash clothes in watery snail habitats. The parasite larvae enter humans’ veins and mature into adult parasites in the liver. The tiny, destructive creatures lay eggs which lodge in the intestines or the bladder. Humans expel the parasite ova back into the water through human waste.

“We’re trying to compare the genetic diversity of populations of the parasitic worm in the North and South of Nigeria,” Greer said. They also hope to obtain samples of the snail host and compare its DNA to that of the worm. “This will help us understand which worm species most often occur in which snail host species. Information about the parasitic life cycle has relevance in public health and may be applied in finding ways to break the life cycle,” he said.

Greer and student collaborators in the laboratory, will first amplify, or make multiple copies of select parasite genes and insert the amplified gene sequences into a carrier DNA, called a plasmid, to be grown up in special bacteria. The plasmids with the parasite sequences are harvested and the parasite DNA sequenced. Comparative analyses are done to determine how the parasitic gene sequences are related to other populations or species of the Schistosoma parasite. The same procedures will be performed next on the snail hosts. “The end result is that we will know more about parasite-host populations and their interactions with each other and their human victims,” says Greer.  

Schistosomiasis is found in Africa, the Caribbean, eastern South America, East Asia, and in the Middle East. It is second only to malaria as the most devastating parasitic disease in tropical countries. At least half of infected persons, or 100 million people, reside in Africa; the disease is most endemic in the African nation of Nigeria, according to The Carter Center in Atlanta, Ga. Former U.S. President Jimmy Carter and former First Lady Rosalynn Carter founded The Carter Center in 1982 toward aiding humanitarian causes.

The center, in conjunction with Nigerian health authorities, dispenses praziquantel through a community-based treatment and drug distribution system in three Nigerian states.

In April 2007, drug maker Merck KGaA announced it would provide 20 million praziquantel tablets per year for 10 years through the World Health Organization based in Switzerland. Last November, WHO representatives announced the organization would in turn provide The Carter Center 1.5 million tablets per year beginning in 2008 for use in the center’s schistosomiasis control program in Nigeria, said Frank O. Richards Jr., The Carter Center’s schistosomiasis control program director and guest researcher at the U.S. Centers for Disease Control and Prevention.

“As a result of this generosity, our treatments in 2008 have tripled,” Richards said. “Still, this is not enough. It is estimated that in Nigeria alone at least 20 million people need treatment, at an average dose of 2.5 tablets per treatment.” 

In addition to Merck KGaA, Bayer AG, Medochemie Ltd., MedPharm International, Shin Poong Pharmaceutical Co., Ltd., and other firms make praziquantel tablets. At about 20 cents per dose, the drug is relatively inexpensive. However most pharmaceutical manufacturers do not volunteer large-scale donations of the medicine and “global industrial capacity to produce praziquantel is likely not sufficient to meet overall global need,” Richards said.

La Sierra University DNA Sequencing and Genomics Laboratory
Greer arrived at La Sierra University in July 2007 from Loma Linda University where he earned his doctorate in biology in 2006. With a Genomics Education Matching Fund (GEMF) grant application to LI-COR Biosciences in Omaha, Neb., Greer obtained $38,154. With this money and with matching funds from long-standing La Sierra University donors, the university purchased for Greer’s lab the LI-COR 4300 DNA Analyzer to read the deoxyribonucleic acid, or DNA, code contained in animal tissue samples. With funding from an LSU College of Arts and Sciences grant, the lab also purchased a powerful number-crunching, spiral-shaped computer with four core processors. The processors perform tandem or parallel number crunching. The computer, which Greer and his students call “the sacred snail,” can perform more swiftly the involved types of genetic analyses needed in the laboratory.

As of spring quarter, 18 students had signed up to study in Greer’s DNA sequencing and genomics lab. “You are doing something much bigger than just acquiring experience for a CV,” Greer tells his student colleagues. Undergraduate researchers in the sequencing lab are gaining the tools and actual experience of doing and eventually publishing basic science, and hopefully gaining a vision of making the world a better place.

Along with the schistososmiasis project, students are engaged in a number of projects including analyzing DNA from new gecko species discovered on limestone karsts in southern Cambodia by La Sierra herpetologist Dr. Lee Grismer. Every year, Grismer treks through Cambodia’s remote Cardamom Mountains, or some other region of southeast Asia, in search of new species of reptiles and amphibians. The DNA lab research ultimately aims at preserving the gecko’s habitat where limestone karsts are being ground down, and at preserving the livelihoods of the Khmer Loeu people. Students are also studying a new pit viper species Grismer discovered on the tiny Vietnamese island of Hon Son. Their work in part targets the preservation of the region’s biodiversity and the rights of its indigenous peoples.

Six of Greer's student researchers this spring quarter wrote four successful Ray Ryckman Endowment for Undergraduate Research grant applications totaling more than $2,600 on behalf of these and other projects in the laboratory. These students included 2008 graduates Tara Lauw, a pre-dental student, pre-medical students Nolan Bayen and Taka Fujimura, as well as senior students Ashish Mesepam and Phuong-Mai Nguyen and senior-with-honors Valitsinee Gift Pattanaprommas.

Greer accepts any student interested in DNA research, but students’ continuation in the lab is based on performance. “Students that are not committed to research tend to weed themselves out,” Greer adds.

Greer is particularly interested in helping students who are struggling against steep odds. “They are already starting to demonstrate the caliber of persistence it takes to succeed in science,” Greer explains. To that end he established a special purpose fund for the lab in April 2007 seeded with his own money. The fund, now also sustained by donations from others, provides grants and paid work opportunities to promising students in dire need of tuition and other assistance. One such student, gifted freshman researcher Caroline Remigio, a foreign student from Brazil, is able to return to LSU because of the lab and various prospective generous donors. Hired in April, then 18-year-old Remigio made tremendous progress in the laboratory and was lead author of a faculty-sponsored science poster for LSU's Research Emphasis Week 2008¹.  

Schistosomiasis undergraduate researcher Janice Liao is another such student. The 20-year-old pre-med junior was leading a stressful, exhausting life that involved long commutes from her parents’ home in Diamond Bar. She struggled with irregular and inadequate sleep and meals wedged between long hours of study and work. And yet, she managed to maintain a quite high grade point average. With some scheduling and accommodation adjustments, some assistance from and work in the lab, Liao quickly distinguished herself by winning a prize for her excellent presentation as primary author of a faculty-sponsored science poster during LSU's Research Emphasis Week².

Liao immigrated to the United States from Taiwan approximately eight years ago with her parents and three siblings. The future scientist-physician lights up when discussing her work on the schistososmiasis project and her goals: Liao hopes to teach preventive medicine to underserved populations, rather than focusing only on treating people after they get sick. And she hopes to help spread the word about the need for funding to buy low-cost schistosomiasis medication. “I really like this project. I’m really excited about it,” she said.

PR Contact: Larry Becker
Executive Director of University Relations
La Sierra University
Riverside, California
951.785.2460 (voice)