
I began my scientific career as a Plant Protection Research Officer in Nematology in Zimbabwe. This was followed by a teaching and research career in Nematology, Parasitology and Invertebrate Zoology at the University of Zimbabwe (UZ). For five years during this period, I was Chair of the Department of Biological Sciences. In addition, I was also a UZ team leader for the joint UZ/Nihon University of Japan research grant for the advancement of molecular technology in vegetable production for the small scale farmers of Zimbabwe, UZ coordinator of a collaborative UZ/IUP exchange link agreement and a fish parasite research collaborator with the UZ/Belgian Flemish Universities Fisheries project.
Prior to my joining Eastern University in Fall of 2005, I spent three and half years at Indiana University of Pennsylvania as a Visiting Professor and later as a temporary faculty in the Dept of Biology. Inspired by the plight of small holder farmers in Zimbabwe in their quest to increase vegetable food production and by my overall desire to be a practical, environmentally conscious scientist in the fight to alleviate hunger among the less privileged, my research interest has remained focused on an ecologically sustainable integrated nematode control strategy.Plant-parasitic nematodes particularly rook - knot nematodes (Meloidogyne spp.,) are a severe constraint on agricultural vegetable production. My current research involves the integrative use of bacteria (Pasteuria penetrans), fungi (Paecilomyces lilacinus), soil solarization and organic amendments in managing root-knot nematodes (Meloidogyne spp.) on vegetable crops. As Christians, we have been commissioned to use our creative capacities to glorify God in service to others and in the management of His creation.
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I was always fascinated by the way in which God intricately designed all living creatures from head to toe (and beyond). As an undergraduate biology major, I became interested in research and spent a summer at SUNY Buffalo School of Medicine investigating agents that affect insulin secretion under a fellowship from the Juvenile Diabetes Foundation. At the University of Pennsylvania where I received my Ph.D., I studied the molecular mechanisms of drug action against the intracellular parasite, Toxoplasma gondii.
My current research explores herbicide action and resistance in Toxoplasma gondii. This parasite, which can infect all vertebrate animal hosts including humans, is a close relative of the parasite that causes malaria. Toxoplasma infection is quite common and goes unnoticed in a large portion of the adult population where a healthy immune system keeps the parasite at bay. However, this parasite can cause disastrous consequences for those with compromised immune systems, such as AIDS patients or the unborn. Infection is controlled through extensive drug treatment protocols, which often yield allergic side effects for the patient. Therefore, alternative treatments to kill Toxoplasma without harming the host are currently being investigated.
In an effort to search for novel chemotherapeutic agents, my research examines herbicide resistance in Toxoplasma gondii. Dinitroaniline herbicides, commercially utilized weed-killers since the 1960’s, have been shown to kill Toxoplasma and other related parasites while exhibiting very low toxicity in mammalian cells. These agents are thought to affect tubulin proteins – cellular building blocks that are necessary to construct microtubules. Microtubules play a role in essential cell activities such as cell division, movement, and intracellular transport. Studies on herbicide action in plants and green algae identified specific mutations in tubulin DNA that correlated with dinitroaniline resistance. To assess the nature of herbicide resistance in Toxoplasma, dinitroaniline-resistant mutants were generated in the laboratory through chemical mutagenesis, and the tubulin genes from mutant parasites were isolated and sequenced.
Parasites resistant to the dinitroaniline herbicide benfluralin exhibited a point mutation in nucleotide position 1801 of α-tubulin (guanine to adenine substitution) which, when translated, revealed a substitution of valine with methionine at amino acid 252. Likewise, parasites resistant to the dinitroaniline herbicide trifluralin exhibited a point mutation in nucleotide position 1850 of α-tubulin resulting in a thymine to cytosine substitution. Translation of this mutated sequence revealed a substitution of methionine with threonine at amino acid 268. These mutations are similar to known mutations that confer resistance to oryzalin (another dinitroaniline) in Toxoplasma or goosegrass.
Electron crystallography data of bovine tubulin dimers was employed to display the mutations on the tubulin protein structure. The amino acid substitutions for the benfluralin and trifluralin mutants are in close proximity of each other in the core of α-tubulin.
To confirm that the identified mutations in the tubulin DNA are responsible for the parasites’ resistance to dinitroaniline herbicides, the mutant tubulin DNA gene will be placed into wild type, non-resistant parasites through transformation, and their conversion into dinitroaniline-resistant parasites will be studied. This aspect of the project is already in progress.
GRANTS RECEIVED
PRESENTATIONS AND OTHER ACTIVITIES
I have always loved nature and wanted to understand how the world around us works, how the plants, animals, water, and soil interact to create such a beautiful world. I majored in Ecology and Marine Biology at Millersville University, where I focused my studies on nutrient chemistry, wetlands, and estuaries. I took field courses at the Marine Science Consortium at Wallops Island, VA and enjoyed learning more about the field aspect of ecological research. I earned my Master’s in Marine Science at the University of Delaware, where my research focused on nutrient and water cycling through the beachface at Cape Henlopen, DE. I stayed at the University of Delaware for my Ph.D. work in Oceanography and returned to research that was more biological in nature – salt marshes! I used aerial photography, LiDAR (Light Detection and Ranging), and GIS to examine the relationship between vegetation and ground elevation in a salt marsh. I also developed a model for determining the role of salt marshes in altering the nutrient loads that flow through them. As a postdoc, I explored paleoceanography using diatoms and bulk sediments from the Southern Ocean.
I am very excited to be a professor at Eastern University and look forward to teaching biology courses, especially environmental courses. My research will continue to focus on nutrient chemistry in wetland and aquatic systems, using remote sensing and GIS to examine vegetation patterns, and examining the relationships between organisms and their hydrological and geochemical environments. I am also interested in studying the impacts of humans on their environment, perhaps through eutrophication studies or examining vegetation change overtime due to human expansion. If you are interested in field research opportunities, please let me know.
I am also excited to be at Eastern University as it will be my first time being part of a Christian academic community. The ability to combine my faith with my passion for science is wonderful, as it will allow me to further understand God. To me, scientific study and research is another way to get to know God, to understand how He thinks, and to worship.
Since childhood, I have been fascinated by the world of living things, their physical characteristics, and how they can be manipulated by changing the physical environment around them. My earliest scientific tour de force was the discovery that garden lettuce and tomatoes do not grow well in sandy soil beneath leafy Maple trees, but thrive in a sunny plot with plenty of composted horse manure. In high school, I became interested in microorganisms, and in college merged my two interests (plants and microorganisms) by studying Plant Pathology – microorganisms that infect plants!
After college, I focused on viruses, microorganisms that infect almost every species on earth. Viruses are obligate parasites, and require a living cell in which to replicate. How these small microorganisms are able to reprogram a much larger organism (like a plant, or a human) to cause disease is a subject of intense research in labs around the world.
In my lab, we are interested in two very different groups of viruses: human retroviruses, specifically human immunodeficiency virus; and a group of plant viruses called begomoviruses. These viruses all cause disease in their respective hosts, and the central question we ask (and try to answer!) is: how do the viruses get into the host cells? Of course, with HIV we also want to answer the related question, what can stop the virus from entering the host cell?
Cyclic peptides to block HIV entry
A great deal is known about how human immunodeficiency virus type 1 (HIV-1) enters a host cell to begin the infection process. HIV entry is a multi-step process that requires both a viral protein and at least 2 cellular proteins on the host cell. This information is essential, because it helps researchers understand what types of drugs could be effective in blocking virus entry. Many of these new drugs have yet to be made and tested, however, and there are many creative ideas that are still in development.
As part of an ongoing project with Dr. Jon Rudick, a protein chemist at Stony Brook University, we are designing and testing novel cyclic peptides to block HIV entry. A panel of cyclic peptides has been synthesized and the first round of testing is completed. We are now using biochemical assays to determine why some cyclic peptides modestly block HIV entry, while others have no effect.
Begomoviruses and their whitefly vectors
Plant viruses that infect food and fiber crops are primarily an economic problem in developed countries, but may have a broad impact on community welfare in developing countries. This is the case with begomoviruses, which infect tomatoes, squash, peppers, cotton, and many other important crops. The viruses are spread from plant to plant by Bemisia whiteflies, which feed on infected plants, taking up the viruses in plant sap and transmitting them to uninfected plants. Bemisia whiteflies are endogenous to tropical and semi-tropical climates, but have now spread to six continents. We are interested in identifying proteins in the whitefly that allow virus acquisition and transmission, and are in the beginning stages of cloning viruses with GFP-tagged proteins in order to follow them as they transit through the insect. Future experiments will require isolation of specific whitefly cell types and gene knockdown experiments.
Both projects share significant similarities in that they require creative experimental design, knowledge of viral life cycles, and lots of molecular biology.
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I received my B.A. degree from Muhlenberg College, and later graduated from the Palmer College of Chiropractic (Davenport, Iowa), magna cum laude, in 1979, where I received my Doctor of Chiropractic degree. After receiving Diplomate status from the National Board of Chiropractic Examiners, passing exams of the Michigan and Pennsylvania Board of Chiropractic Examiners and the New Jersey Board of Medical Examiners and receiving licenses to practice within these states – I associated in Michigan, Pennsylvania, and New Jersey in 1984, and had a private practice in Ocean City, N.J., until retiring in summer 2006.
My continuing education has been ongoing since graduation, and has included over 800 hours of coursework encompassing Physical Therapy, Orthopedics, Sports Injury, Biomechanics, Nutrition, Pain Control, Diagnostics, and Radiology.
During my years in Ocean City, my practice was a family- oriented, treating patients of all ages. In addition to treating the subjective complaints of my patients, I was fortunate to be able to integrate my Christian faith into my professional private practice by making my practice a place where one could receive more than just the NJ state mandated/recognized standards for chiropractic care and treatment. I also used it as a place to “plant seeds” and witness.
From the time I was young, I wanted to be a nurse. This I accomplished when I received my BSN from Penn State, and worked in critical care for 15 years. By then, my other passion, physical fitness, became a new professional pursuit for me. I became increasingly interested in the role of exercise in the health of the human body.
Exercise is not merely a recreational pursuit, but a first-line therapeutic treatment for many of the diseases, such as those I encountered as a nurse. Furthermore, if implemented with regularity, exercise can help prevent the diseases that kill the majority of people in developed countries.
This led me to graduate school at Temple University where I received my Ph.D. in Exercise Physiology. My passion became studying the human body; in disease, in health, and in response to physical activity.
I am interested in all aspects of exercise and health. My research at Temple involved regulation of body temperature in men and women during exercise in hot and humid conditions. I also studied thermoregulation of exercising women at different points in their menstrual cycle. I assisted others on studies that looked at nutrient use of obese women during exercise, and insulin sensitivity in exercising rats. I have become convinced that the human body was exquisitely designed and intended by our Creator to do and adapt to physical work. Furthermore, the lack of physical activity leads to less than optimal physical and mental health. I am delighted to teach anatomy, physiology, and health-related courses here at Eastern University. I especially enjoy teaching students about the miracle that is the human body, and how to best care for the temple of the Holy Spirit.
I have worked in ecological consulting since 1973, with extensive experience in applied ecology (Environmental Impact Statements, mitigation plans, regulatory consulting, etc.). In recent years, my professional design and consulting work has focused on the restoration of degraded or destroyed natural ecological systems, especially wetland habitats. I have taught 16 courses, mostly for professionals, and developed and teach the Environmental Regulation & Policy course (Bio. 420) at Eastern University every spring of odd-numbered years.
I began my scientific career as a plant breeder, studying both genetics and agronomy/agricultural ecology. After several years at the University of Puerto Rico, researching disease resistance and harvest quality in vegetables and dry beans, I worked at the Fox Chase Cancer Center in Philadelphia, studying tropical plants with potential antiviral effects as part of a five year grant. I came to Eastern in 1992, where I teach Ecology and related courses. Two of my most popular electives are 'Medical Botany', and 'Tropical Biology'. Since 2003, I have taught 'Tropical Agriculture and Missions' through the Au Sable Institute and ECHO, based in south Florida.
Much of my focus outside teaching is currently in service related to sustainable agriculture. I serve as a trustee on the boards of Christian missions that focus on sustainable community development. For these organizations, as well as with mission teams from Eastern, I often travel to Latin American countries. ECHO (www.echonet.org) is a Christian service mission providing training and agricultural extension in poorer countries globally, Floresta (www.floresta.org) promotes reforestation, especially in the Caribbean basin and Hope Seeds (www.hopeseeds.org) aids many relief and development programs of other organizations with appropriate, high quality seeds.
I also teach a course (BIO 180- Science in Society), built around a case study of genetics and the concept of "race". Partly out of my own personal experience growing up in Chicago and later living and traveling in Latin America, partly out of my training in genetics, and always rooted in the Bible, addressing the damage done by the concept of race is a priority for me. Shattering the myth of race: genetic realities and Biblical truths developed out of this class, and is available from Judson Press (www.judsonpress.com).
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My education is in medicine and population biology, and my specific scientific research interests center on theoretical models of fitness, the nature of genomic blueprint hierarchies, selective models for punctuated change, and human origins. I have written and published a number of integrative studies in the faith / science area, including a book length manuscript Supernatural Selection in review for publication. My presuppositions for science (and life) begin with the conviction that we live in an open and providentially governed universe which the Lord Jesus Christ creates, maintains (holds together), and governs by the Word of His power. That activity, I maintain, we usually call natural law, and science is possible because He is faithful in that governance. I also assume the (limited) rationality of the human mind (made in God's image) which can therefore hope to understand God's universe.
Further, I consider scientific investigation to be a particular sort of response to the Creation Mandate given to humanity. Thus, the business of a particular science (like biology) is to investigate a specific aspect of that "word" as it manifests itself in the world around us.
PUBLISHED WORKS
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