Volume V Number 1 Winter 2008/09
O F F I C I A L P U B L I C AT I O N O F T H E A D VA N C E D F O O D S A N D M AT E R I A L S N E T W O R K
Partners in peptides
Prof. Rotimi Aluko (bottom left) of the University of Manitoba and his research team are using peptides from peas to find a cure for hypertension and kidney disease.
page 10
INSIDE:
• Consumer food panel page 8 • Encapsulating probiotics page 12 • Yogurt for AIDS relief page 16
Welcome The official publication of the Advanced Foods and Materials Network A publication to promote dialogue and understanding about sophisticated foods and materials research across Canada Executive Editor Louise Jessup Project Co-ordinator Kaitlyn Little Project Manager Lise Smedmor
Copy Editor Stacey Curry Gunn Design JnD Marketing Financial Manager Jan Smith Address correspondence to: Louise Jessup, Communications Manager 150 Research Lane, Suite 215 Guelph, Ontario, Canada N1G 4T2 E-mail: louise.jessup@afmnet.ca Visit the AFMNet website: www.afmnet.ca This publication was written by students in the SPARK program, Students Promoting Awareness of Research Knowledge, at the University of Guelph in Ontario, Canada.
Dr. Larry Milligan
Editor Owen Roberts
Welcome to our fifth annual edition of Advance, the official publication of the Advanced Foods and Materials Network (AFMNet). AFMNet is Canada’s national food and biomaterials research network. Our researchers are helping to produce commercially viable, socially acceptable, value-added products and processes that benefit all Canadians. Partnering with industry, government, not-for-profit organizations and national and international research institutions, AFMNet’s vision is for a healthier Canada. In this issue you will find interesting updates on research stories from past issues. You will read about the progress that Gregor Reid and his team have made using probiotic yogurt to treat patients with HIV/AIDS and other immune deficiencies and malnutrition; the exciting work being done by Louise Nelson and Peter Sholberg to solve the age-old problem of post-harvest fruit loss due to fungal decay; and how Ahmed El-Sohemy and his team have provided the first evidence that a variation in the GLUT2 gene plays a role in sugar intake, which helps explain individual preferences for high-sugar foods. We also bring you news of many other projects of benefit to Canadians. You will see how Rotimi Aluko (cover) is developing a natural approach to reduce hypertension (high blood pressure) in kidney patients; how Spencer Henson and John Cranfield have created a large-scale consumer network to allow researchers to accurately track changes in Canadian eating habits and measure consumer response to issues like food scares; and how Yoshinori Mine has provided the first evidence of the tremendous antioxidant potential of eggs yolks in the treatment of gut-related diseases. AFMNet looks forward to more exciting developments in 2009, as we enter our third project cycle. We will be welcoming many new faces to our research network and continuing to benefit from the innovation and insight of many familiar ones. We hope you enjoy this issue, and encourage you to share it with others. As always, we welcome your feedback and ideas.
Dr. Rickey Yada
Volume V Number 1 Winter 2008/09
Publications Mail Agreement Number 40064673 Please return undeliverable Canadian addresses to: AFMNet, 150 Research Lane, Suite 215, Guelph, Ontario, Canada N1G 4T2
Sincerely,
Chief Research Officer, AFMNet
Chair of the Board of Directors, AFMNet
AFMNet – ADVANCE 2009
3
CONTRIBUTORS All contributors to Advance are part of Students Promoting Awareness of Research Knowledge (SPARK) at the University of Guelph. SPARK’s mandate is to write and broadcast research in ways that are relevant to the public. Clockwise from right: Third-year economics student Arpana Chakravarty knows that the consequence of lost productivity is a decrease in supply. Creating transgenic plants that can withstand pathogens and disease will greatly increase field productivity and result in a greater supply of food, battling possible food shortages. Read her story on page 14. Anupriya Dewan, a fourth-year nutrition and nutraceutical science student, enjoys learning about how to naturally heal and treat illnesses. A researcher’s discovery of isolated pea peptides and their ability to treat hypertension is the focus of Anupriya’s natural-healing story on page 11. Fourth-year public management student Kaitlyn Little knows the importance of understanding consumers views and attitudes around new products. The co-ordinator of this issue of Advance writes about how a new consumer panel is providing insight into the acceptability of functional foods and nutraceutical products on page 8. Tailoring goods to a specific group of people requires a targeted marketing approach, so that those products reach the intended market. Andrea Hruska, a third-year marketing management student, took a close look at the development of a probiotic yogurt designed to help AIDS patients and the researcher’s efforts to get it to those most in need. See her story on page 16. Encapsulated probiotics are protected on their journey to the colon, where they offer maximum benefit. Matthew DiCicco, a third-year biological engineering student, highlights the benefits of engineering foods to enhance human health in his story on page 12.
Photo by Dave Peleschak
4
AFMNet – ADVANCE 2009
CONTENTS
Foods and Health
6
A new approach to gut health
6
A gene that controls carbohydrate cravings
6
Taking a closer look at CLA
7
Consumer and Ethical Issues
8 10
16 Cover photo by Ian Causland
Functional foods examined by new panel
8
Ethical issues around animal biotechnology
9
Materials Fighting kidney disease with pea peptides
10
This research really gels
11
Intestinal health benefits from bacteria
12
Proteins that CAP disease
13
Strategic Transition and Research Application Transgenic plants increase productivity
14
Preventing post-harvest rot in apples
15
Yogurt provides AIDS relief
16
AFMNet – ADVANCE 2009
5
Foods and Health
Sugar craving? Blame your parents By Arpana Chakravarty People with a genetic variation in a gene dubbed GLUT2 – which controls sugar entry into cells – tend to consume more sugar than those without it, say University of Toronto researchers. Prof. Ahmed El-Sohemy, Department of Nutritional Sciences, and PhD candidate Karen Eny are examining the biological reasons behind people’s food consumption behaviours. “This line of research helps us understand why some people, based on genetics, consume more sugars than others,” says Eny. In their research studies, the team found that people with the genetic variation consumed more sugars, especially
University of Toronto researchers Prof. Ahmed El-Sohemy and PhD candidate Karen Eny have found the sugar cravings some people experience may be caused by genetic variations in the GLUT2 gene, which causes them to consume more sweets and sugary drinks. from sweets and sweetened beverages, than those without the variation. Potential confounders such as age, sex, physical activity and BMI did not have an impact on the results. With the rise of obesity and type-2 diabetes, there is growing interest in understanding how genetics plays a role in these diseases, says Eny. The researchers hope this study’s findings will provide insight into the role GLUT2 plays in carbohydrate consumption and how this may affect diabetes risk, which is linked to obesity. A number of biological reasons may be behind people’s food consumption behaviours. The research team’s work with GLUT2 suggested this glucose transporter monitors the level of sugar in the blood, to signal the brain to eat or to stop eating. That helps maintain adequate levels of sugar to fuel our body.
Precision cutting An egg peptide sliced just right may hold the key to treating Irritable Bowel Disease By Anupriya Dewan
6
AFMNet – ADVANCE 2009
Besides providing energy, sugars can also enhance mood for some people more than others. Now the team is investigating whether a variation in a gene that affects the actions of dopamine – a mood-altering chemical that occurs naturally in the brain – explains why some people consume more sugars than others. For those people, consuming sugars might be more related to how it makes them feel. This research was funded by AFMNet, the Canadian Institute of Health Research and a Julie Payette Research Scholarship that Eny received from the Natural Sciences and Engineering Research Council. Other collaborators involved in this study are University of Toronto Prof. Thomas Wolever and graduate student Bénédicte Fontaine-Bisson. l
There’s a new approach emerging to try to solve the mystery of Irritable Bowel Disease (IBD), a condition on the rise in Canada. Prof. Yoshinori Mine, Department of Food Science at the University of Guelph, is examining a peptide isolated from egg yolk that can decrease gut inflammation caused by diseases such as IBD. This permits the condition to be managed without the adverse side effects that may accompany medications. “Just eating eggs won’t help with the symptoms. Dietary interventions are necessary,” says Mine. “You have to extract the peptide using an enzyme, and then consume it as a supplement to get the health benefits.”
New questions about fatty-acid supplement CLA shows promise in animal studies but needs a closer look for human use By Anupriya Dewan and Andrea Hruska The jury is still out on the effectiveness and safety of a fatty acid marketed as a human weight-loss supplement, although it has been shown to work in animals. At the same time that Europe approved a conjugated linoleic acid (CLA) supplement that claims to help people shed pounds, research emerged in Canada showing CLA could not be proven to promote weight loss in humans. Preliminary animal studies were promising; CLA was shown to be effective for reducing weight as well as possessing anti-cancer properties. But the benefits don’t seem to transfer to humans. In fact, CLA may be causing adverse
health effects, says University of Manitoba researcher Peter Jones. “An increasing number of clinical trials show that CLA is not working, and here it is being approved by the [European] government,” says Jones. “We need to figure out why it works in animal models and not in humans.” Indeed, findings several years ago resulted in the popularization of CLA supplements as weight loss agents. In previous human studies, a group of patients were given the CLA supplement and the rest were given a placebo. The CLAingesting group lost more weight, but a trial conducted by Jones failed to replicate that
Scientists believe IBD may be caused by stress, lifestyle and diet. The disease is characterized by inflammation of the gastrointestinal tract, resulting in cramping, abdominal pain, constipation and diarrhea. Other chronic diseases, including diabetes, are linked to IBD, making it a condition with far reaching consequences. Currently, the only way to treat it is by reducing its symptoms with the use of steroids, which leads to other side effects. Mine has found that the peptide is activated when its proteins are cut at
specific spots. Once activated, it can help reduce the inflammation associated with IBD. This activated peptide can be used as a supplement in a variety of products, including juices, or in capsule form. Supplementation is necessary because, unfortunately, humans can’t convert the protein from eggs into this beneficial peptide. Pepsin – an enzyme in the human stomach that breaks down proteins – doesn’t cut the protein at the spots needed to activate the peptide. “We want to improve gut health and immunity to improve lives and prevent
data. What caused the weight loss in the original study was – and still is – unknown. Jones says weight loss may be caused by a state of inflammation caused by CLA. Increased liver mass or inflammation is characteristic of a condition known as fatty liver disease (fat being accumulated in the liver), which is caused when the liver is stressed by removing toxins from the blood. Another suspected reason for this discrepancy between animal models and humans is the young age of the animals in studies, versus human adults. Animals not fully grown may be using CLA in a different way, resulting in the weight loss. “Public safety needs to be at the forefront of everyone’s mind when we are looking at food additives. We need to make sure it’s not harmful,” says Jones. Others involved in this research are Prof. Roger McLeod, Dalhousie University; Profs. Spencer Proctor, Catherine Field and Donna Vine, University of Alberta; Profs. Helen Jacques and Andre Marette, University of Laval; Harold Aukema, University of Manitoba; Prof. Stephen Cunnane, University of Sherbrooke; and Drew Wakefield of the Univerity of Manitoba’s Centre for Functional Foods and Nutraceuticals. Funding has been provided by AFMNet, Beef Information Centre, Alberta Agriculture and Rural Development, Dairy Farmers of Canada, Alberta Livestock and Development Fund, National Dairy Council, and the Agricultural Bioproducts Innovation Program. l
diseases by foods. This way we can develop products to improve Canadians’ health,” says Mine. Also involved in this research are University of Guelph Prof. Ming Fan of the Department of Animal and Poultry Science, University of Toronto nutritional scientist Prof. Ahmed El-Sohemy, and Rong Cao of Agriculture and Agri-Food Canada. Funding for this project has been provided by AFMNet. l
AFMNet – ADVANCE 2009
7
Consumer and Ethical Issues
A quick read on Canadian consumers New research panel reveals views and consumption patterns of functional foods These Enviropigs are an example of animal biotechnology. Created at the University of Guelph, Enviropigs are genetically modified to better use dietary phosphorus, reducing surface and ground water phosphorus contamination.
Gaining insight quickly and thoroughly into Canadian consumers’ perceptions of food – including the acceptability of functional foods and nutraceutical products – is easier and more accurate thanks to a consumer food panel created at the University of Guelph. The panel, developed by Profs. John Cranfield and Spencer Henson, Department of Food, Agriculture and Resource Economics, uses bimonthly online surveys of the same group of individuals to better understand consumer views of food, health and agricultural products such as functional foods and nutraceuticals. “Using the panel we are able to see how people’s concerns, perceptions and consumption patterns of food change over time,” says Cranfield. “Knowing this will allow us to better understand what drives consumer acceptance.” The panel consists of 2,000 Guelph consumers who are representative of the city based on their age, education level and gender. The research team chose Guelph specifically, because its population broadly represents the overall Canadian population. When looking at consumer acceptability of functional products, researchers have found that demographics are irrelevant. Acceptability comes down to attitudinal and behavioural factors, they say. Two groups of consumers emerged when looking at attitudinal factors: those who are price sensitive, and those whose acceptance is based solely on the health and nutrition information of the product. With the price-sensitive group, the nutritional benefit had no impact. Decisions to purchase the
8
AFMNet – ADVANCE 2009
product always came back to its price. However, as the industry develops, product prices will generally start to come down, Cranfield predicts. On the flip side, as the reported nutritional benefit of the product increased, consumer acceptance followed in the group whose uptake was based on health and nutrition information. When looking at behavioural factors, the panel revealed that the consumers who are most likely to buy foods with functional compounds already exhibit healthy behaviours. The panel also found the meaning of “functional foods” remains unclear to many consumers. Cranfield says the industry needs to better communicate about these foods and nutraceutical products, especially the most common ones. For example, consumers might not make the connection that their probiotic yogurt falls into this category of being a functional food, he says. With the panel, researchers hope to track individuals over time and ask follow-up questions to see how views and attitudes relate to previous answers. “Better understanding consumer acceptance will allow researchers and industry to develop products that meet consumer demand,” says Cranfield. Also involved in this project are post-doctoral researchers Oliver Masakure and Jose Blandon of the Department of Food, Agriculture and Resource Economics at the University of Guelph. This research is funded by AFMNet and the Ontario Ministry of Agriculture, Food and Rural Affairs. l
Cecil Forsberg
By Kaitlyn Little
Unravelling values and ethical concerns around animal biotechnology By Kaitlyn Little Investigating the value and ethical concerns of animal biotechnology – using research on what stakeholders think about specific applications, including genetically modified animals and cloned animals – is the focus of a new book that combines stakeholder views with expert opinion. It will be published by University of Toronto Press in 2009.
Prof. Sarah Hartley, Department of Political Science, Simon Fraser University, and Prof. Conrad Brunk, Department of Philosophy, University of Victoria, secured six expert researchers to write chapters that draw on the results of a series of stakeholder focus groups. In these groups, the researchers engaged participants to explore their perspectives on issues raised by animal biotechnology, says Hartley. “This approach to research is not supposed to be representative of the overall Canadian population. Instead it represents a flavour of what stakeholders think about the issues,” says Hartley. Seven focus groups were conducted with key stakeholders, including research scientists, government regulators, farmers, health researchers, health care providers and representatives of alternative agriculture and animal justice. During the focus groups, researchers presented the participants with 10 possible applications of animal biotechnology – ranging from cloning bulls for agricultural purposes to genetically modifying mice for human health research – and asked participants to rank their selections from the most supportable to least supportable. Researchers were not interested in the participants’ rankings per se, but used the exercise to understand the values behind the rankings and the value tradeoffs that were made. The focus groups resulted in some interesting findings. For example, they showed that among the various stakeholder groups there seemed to be a perceived
hierarchy of being – that is, the closer to humans the animal ranked on the phylogenetic scale, which measures relatedness in terms of common ancestors, the more adverse reaction participants had to a specific animal biotechnology application. An example of this is that applications involving a mouse or a fish were deemed more supportable than those using primates. Another finding was that using animal biotechnology strictly for economic gain was not particularly supportable. For instance, the focus group participants across all stakeholder groups found that goldfish that glow in the dark (sold as a novelty fish in the U.S.) are frivolous and therefore not easily supportable. The book examines these values and ethical issues and others in six chapters that include industrialized agriculture, alternative agriculture, animal justice, health care, health research and religion. The introduction and a final chapter that deals with the regulatory implications of these findings will be penned by Hartley and Brunk. The book also includes two chapters outlining the current state of the science of animal biotechnology and the ethical issues related to it. “The hope is that this book will contribute to the debate on animal biotechnology and provide information for those who are interested in seeing a range of opinions on the issue,” says Hartley. Chapter authors include Mickey Gjerris, University of Copenhagen; Paul Thompson, University of Michigan; Lyne Letourneau, Laval University; Harold Coward, University of Victoria; Nola Ries, University of Alberta; Peter Phillips, University of Saskatchewan; and Lori Sheremeta, University of Alberta. Cecil Forsberg, University of Guelph, and David Fraser, University of British Columbia, are the scientific advisors for the project. Michelle Illing, Canadian Food Inspection Agency, and Amanda Whitfield, Health Canada, are the project’s government partners. Other project partners included Keith Pitts, formally from the Pew Initiative and Genome BC. This project is funded by AFMNet. l
AFMNet – ADVANCE 2009
9
- Prof. Rotimi Aluko
Giant killer
Ian McCausland
“Inhibiting renin is like cutting off the head of a giant called hypertension.”
Prof. Rotimi Aluko, University of Manitoba, is working with pea peptides that can reduce hypertension and cure kidney disease.
10
AFMNet – ADVANCE 2009
Materials Pea peptides fight hypertension and kidney disease By Anupriya Dewan Pea proteins that have been hydrolyzed and split into smaller pieces called peptides have been shown to combat kidney disease and hypertension, say researchers at the University of Manitoba. Prof. Rotimi Aluko, Department of Human Nutritional Sciences, says pea peptides provide relief for hypertension in two ways. They block renin, the root cause of increased blood pressure found early on in the biochemical pathway, and they reduce kidney disease progression. Current medications target Angiotensin Converting Enzyme (ACE), which amplifies the effects of renin, making it a less effective method of curing the kidney disease. The body regulates blood pressure using a variety of compounds, including renin, by changing the diameter of blood vessels. Renin increases blood pressure by producing a compound that helps blood vessels contract. But if excess renin is released, blood vessels contract more than they should, increasing blood pressure to dangerous levels. ACE normally amplifies renin’s effect and makes the problem worse. “Inhibiting renin is like cutting off the head of a giant called hypertension. It can’t be a problem anymore,” says Aluko. “Blocking ACE is like cutting off an arm or a leg. The giant still lives.” The isolated pea peptides block renin’s activity, which prevents the blood vessels from contracting excessively. With the blood vessels dilated, the blood pressure remains normal because there is more space for blood to flow through. With little renin activity present, there’s also no amplification due to ACE, solving the problem at its root. As a result, these peptides are more effective at treating hypertension than drugs on the market today, because medications target ACE, not renin. The isolated peptides also increased cyclooxygenase 1 (COX1) levels, which is known to reduce inflammatory agents released by the kidney. Reduced inflammation improves kidney function and reduces the ability of kidney disease to elevate blood pressure, solving this cause of hypertension at its root. Animal studies look promising and are targeting the root cause of the problem for the first time, but the work isn’t done yet. Aluko plans to do clinical studies to measure the impact of the peptides on humans. “Curing hypertension may become as easy as drinking juice or taking a pill that contains the peptide,” says Aluko. Also working on this project are Prof. Harold Aukema and Prof. Paramjit S. Tappia from the University of Manitoba. Funding for this project has been provided by AFMNet, the Natural Sciences and Engineering Research Council and the Manitoba Centre of Excellence Fund. l
Get-well gel Antimicrobials could be a new remedy for bacterial infections By Hayley Millard Experience has shown that naturally occurring antimicrobials can effectively fight off bacterial infections. However, many of these compounds are highly reactive and rapidly break down before they actually come in contact with undesirable bacteria. If researchers could find a way to overcome this obstacle, antimicrobials could become a more practical treatment for bacterial infections than antibiotics, where overuse can produce antibiotic-resistant bacterial infections. Prof. Dérick Rousseau, Ryerson University, and Prof. Allan Paulson, Dalhousie University, are working with allyl isothiocyanate (AITC) – a highly water-soluble antimicrobial. Although AITC can effectively suppress bacterial growth, it reacts with other compounds in the body before encountering the actual problem: harmful bacteria. Rousseau and Paulson want to harness this compound so it will react only at the site of the infection. And they say rigid gel structures called hydrogels are the answer. Encapsulating antimicrobial compounds such as AITC in gel capsules that could be swallowed, or in gel patches that could be placed on the skin, would control the reactive element’s release. When the capsule is swallowed, or the patch is placed on the skin, the gel swells, enlarging its pores. Modifying the pores’ expansion rate controls how quickly the compound within the gel is released. Rousseau and Paulson are experimenting with the hydrogel’s intricate formation to control the size of the gel’s pores and how they expand when gel swells. “We’re looking at controlling the rate of diffusion for a slow, timed release of the encapsulated compound,” says Rousseau. “If the pores are too small, not enough of the antimicrobial compound will pass through, but if the pores are too big, too much will pass through too quickly.” Others involved in the research include Profs. Michael Nickerson of the University of Saskatchewan; Gianfranco Mazzanti and Lisbeth Truelstrup Hansen of Dalhousie University; Pascal Delaquis of Agriculture and Agri-Food Canada; and physicist David Pink from St. Francis Xavier University. This research is funded by AFMNet. l
AFMNet – ADVANCE 2009
11
Materials
Beneficial bacteria ease intestinal ills Researchers are looking at new techniques for better colon health By Matthew DiCicco Probiotics – sometimes called “helpful” bacteria – are said to reduce colon cancer, increase mineral absorption and outcompete harmful bacteria. Researchers at the University of Saskatchewan are exploring new ways to help probiotics get to the large
12
AFMNet – ADVANCE 2009
intestine safely, and to flourish there. Some good bacteria naturally inhabit the colon. However, they can’t prosper without a proper diet and help from prebiotics – food ingredients that stimulate probiotic growth, helping to crowd out bad bacteria such as Escherichia coli. That’s where Prof. Nicholas Low and his research team at the Department of Food and Bioproduct Sciences come in. They’re conducting research on how to effectively combine and encapsulate prebiotics and probiotics for transport and delivery to the large intestine. “This research could be of significant health benefit to people everywhere,” Low says.
The project’s main focus is to find appropriate oligosaccharides – carbohydrates found naturally in many plants – to use as prebiotics, and to determine how they affect probiotic growth. Oligosaccharides make good prebiotics because they’re a superb carbon source for probiotics, and are not utilized well by harmful bacteria. They usually escape digestion in the small intestine and make it to the colon where they can support the growth of “helpful” bacteria. Most probiotics found in food are mainly in yogurt and other cultured dairy products. Typically, they are killed by the stomach’s harsh acidic environment, by common food processing techniques, or by both. The stomach is designed to kill off bacteria, good or bad, so the researchers are looking to find an efficient balance of prebiotics and probiotics that they can encapsulate to reach the right spot in the intestines. Encapsulation is an important component of the research. Without proper protection, the probiotics will die in the stomach en route to the large intestine, or travel past the colon without disintegrating. Encapsulation with a suitable protein could help the compound to bypass the stomach and disintegrate at the correct time and place leading to maximum health benefits. In the future, this multi-component material will be employed as a food ingredient to produce functional foods with the goal of targeted delivery in human and animal digestive systems. Right now, however, getting the three components working together effectively will be a big achievement on its own. “It is a significant scientific endeavor to get these three components working together,” says Low. Others involved in this research project are Profs. Michael Nickerson and Darren Korber, Department of Food and Bioproduct Sciences, University of Saskatchewan. Funding for the research is provided by AFMNet, the Saskatchewan Agricultural Development Fund and Bioriginal Food & Science Corporation. l
These natural proteins CAP disease By Arpana Chakravarty Bacterial food-borne illnesses pose a threat to food supply. In addition, there is a need to extend the shelf life of foods. Dalhousie and St. Francis Xavier university researchers are hoping to improve the situation with anti-bacterial proteins. All living organisms are equipped with small innate protein molecules that naturally fight bacteria, known as Cationic Antimicrobial Peptides (CAPs). Finding out how CAPs enter bacteria will allow researchers to better understand how these peptides work to destroy disease-causing and spoilage-promoting bacteria. Prof. Tom Gill at Dalhousie’s Department of Process Engineering and Applied Science is looking at how CAPs inhibit Gram-negative bacteria – a group of bacteria with a unique cell membrane structure. “CAPs are part of Mother Nature’s natural defense,” says Gill. “They’re built into every living organism, so why not use them to preserve our food?” CAPs have a unique ability to enter and destroy bacteria. Gill is testing to see if and how peptides enter through porins – barrelshaped proteins on a bacterial cell’s outer membrane that allow nutrients and wastes in and out of the cell – so he can mimic the porins’ structure and develop a successful synthetic version to use in food. Gill extracts protamine, a type of CAP
naturally found in herring, and purifies it. Then, his colleagues separate the porins from the bacteria and insert them into an artificial cell wall to observe protamine’s chief method of entry. Part of this multidisciplinary approach involves Prof. David Pink, a theoretical physicist at St. Francis Xavier University. Pink predicts molecular behaviour using mathematical modeling and computer simulations. His coworkers can then verify the outcomes experimentally or predict and understand new experimental measurements. To deliver peptides to the intended site of attack, researchers have been trying to design a platform for delivering CAPs with barrel-like porins so the peptides won’t be digested by bacterial enzymes or unintentional targets upon entry. Pink developed a mathematical model and computer simulation for the proposed delivery system. Although this system still needs to be tested in the lab, his results look promising.
treatment options, a serious problem that CAPs may solve. The results from this project may lead to the development of new antimicrobials (drugs that kill or prevent the growth of microbes, including bacteria, fungi and viruses) and, perhaps in the future, better antibacterial compounds for the health sector. “We are addressing a problem that both the health sector and food industry are struggling with,” says Pink. This research is funded by AFMNet, the Natural Sciences and Engineering Research Council and the Atlantic Innovation Fund. Others involved in this research include Prof. Erich Sackmann, Technical University of Munich, and Prof. Motomu Tanaka, Heidelburg University. The late Terry Beveridge, Department of Molecular and Cellular Biology at the University of Guelph, was also involved in the study. l
Eduardo Luzzatti Buyé
“We are cautiously optimistic that we might have come up with a delivery vehicle that will deliver the CAP to bacterial surfaces,” says Pink. Research shows long-term treatment with CAPs doesn’t produce the same type of bacterial resistance as other antimicrobial compounds, including penicillin. Bacteria are gaining resistance to conventional
Protamine, a Cationic Antimicrobial Peptide (CAP), naturally found in herring, was used by researchers to discover how the peptide kills bacteria. Researchers can use this knowledge to create a synthetic version to use in food preservation.
AFMNet – ADVANCE 2009
13
Strategic Transition and Research Application
Using peptides to protect yields By Arpana Chakravarty
Ravinder Kumar
Antimicrobial peptides -natural disease-fighters found in frogs and insects -are inserted into plants by Dr. Dmytro Yevtushenko and Dr. Ravinder Kumar, University of Victoria, to create illness-resistant transgenic plants.
Engineering plants resistant to common diseases will help increase crop productivity, says an AFMNet member. Dr. Ravinder Kumar of the University of Victoria says his work will help alleviate the rising demand for food that will accompany an increase in population. “Food scarcity can become a major issue if adequate measures are not taken now. So, it’s necessary to have an appropriate technology to protect our yields…and we have [it],” he says. Kumar’s research group is working with types of proteins that naturally fight diseases, called antimicrobial peptides (AMPs). The researchers have inserted peptides into several species of plants to make them resistant to a diverse group of pathogens, including mycotoxic fungi, which pose serious food safety issues.
14
AFMNet – ADVANCE 2009
The peptides are collected from a variety of sources, including frogs and insects, which live in a challenging environment and have a natural ability to prevent infection. Peptides are made under the direction of a gene, so once the target peptide is identified, its gene is then transferred to plants. The resulting transgenic plants are tested rigorously against a spectrum of pathogens. Augmenting plants’ natural immunity is an eco-friendly alternative to using pesticides, says Kumar. “Unlike other ways of incorporating resistance in plants that are associated with poor yield, we are glad to say that this technology increases plant productivity by 15-20 per cent even in the absence of diseases,” he says. “This technology has an added advantage of preventing field and storage losses while providing safer food.” Currently, the group is working towards turning the gene on only whenever and wherever it’s required. The approach would alleviate the concerns of those who are wary of transgenic crops. “I believe that this research is important because, as the world population is growing, arable land is shrinking, meaning there is more pressure for field productivity. If we have a certain technology developed, we can use it anytime. We may not need it now, but we must think down the road when the traditional way of doing agriculture is not sufficient,” says Kumar. Next, Kumar plans to conduct field studies in India. Dr. Kumar’s group is headed by Prof. Santosh Misra, Department of Biochemistry and Microbiology, University of Victoria. Also involved in this research is Dr. Dmytro Yevtushenko of the university’s Department of Biochemistry and Microbiology. This research is funded by AFMNet. l
Rot stops here By Kaitlyn Little Tim Swanky
When apples on trees are exposed to fungal pathogens, post-harvest rot can occur during storage. This problem costs the apple industry five to 10 per cent a year in crop losses. Now, researchers at the University of British Columbia have developed a two-pronged approach to protect apples from these pathogens. Their method combines on-site pathogen detection and the use of an organic biological control agent that is applied to protect exposed apples. Prof. Louise Nelson, Department of Biology and Physical Geography, and her research team have developed a DNA-based macroarray technology that allows detection of the three most prevalent pathogens (blue mould, grey mould and mucor) from samples of the air, leaves and blossoms in an orchard during the growing season. They have also developed several soil bacterial isolates for use as an organic biological control agent to protect the apples from rotting while in storage. “Our goal is to develop new economical methods for the detection and control of fungal pathogens,” says Nelson. After the first field trial, researchers found that the soil bacterial isolates were effective in protecting the apples for the first three months of cold storage. The team will now study the survival of the isolates on apples during storage beyond three months, an important health and regulatory consideration prior to commercialization of the product. Next, the researchers will use the DNA macroarray technology to try to determine the relationship between weather and factors such as leaf wetness, a pathogen’s presence at blossom and fruit set, and the incidence of disease during storage. They hope to develop a prediction model that will assist growers in determining the probability of disease occurring during storage. Others involved in this research are postdoctoral researcher Danielle Hirkala and graduate student Daylin Mantyka from the University of British Columbia and Peter Sholberg of Agriculture and Agri-Food Canada’s Pacific Agri-Food Research Centre. This project is funded by the AFMNet. l
From left, University of British Columbia researchers Daylin Mantyka, Prof. Louise Nelson and Danielle Hirkala are working towards early detection methods to protect against post-harvest rot.
AFMNet – ADVANCE 2009
15
Strategic Transition and Research Application
Consuming micronutrientsupplemented probiotic yogurt can greatly reduce AIDS side effects such as nausea, decreased immunity and diarrhea.
Yogurt with a difference HIV/AIDS patients can benefit from eating micronutrient-supplemented probiotic yogurt By Andrea Hruska
Ina Peters
Nausea, decreased immunity and diarrhea are some of the side effects many HIV/AIDS patients experience every day, especially as their immune system weakens. Fortunately, many side effects may be eased or potentially eradicated with daily consumption of a newly formulated, micronutrient-supplemented probiotic yogurt, say researchers at the Lawson Health Research Institute. Prof. Gregor Reid, University of Western Ontario Department of Microbiology and Immunology, and Jaimie Hemsworth, a MSc student from Brescia College, have recently finished testing micronutrient-supplemented probiotic yogurt – a regular yogurt with Lactobacillus rhamnosus GR-1 and a range of micronutrients added. “We modulate our health in many ways through the food we eat,” says Reid. “The bacteria inside us play a huge role in our very existence.” Probiotics improve immunity in a number of ways, including by signalling the T-cells – a type of white blood cell that attacks invaders – to begin working. In HIV/AIDS patients, the depletion of their immune system (measured by a lowering of their CD4 cell count) makes them highly susceptible to common viruses such as the flu, pneumonia and
16
AFMNet – ADVANCE 2009
the common cold, and harmful bacteria. In the spring of 2008, Hemsworth performed a pilot study at the HIV Clinic in London, Ontario that showed the micronutrient-supplemented probiotic yogurt had potential to improve the wellbeing of HIV patients. She then travelled to Africa to the Lawson research site at the National Institute for Medical Research in Tanzania to determine if the concept could help AIDS patients there. A program called Western Heads East had already taught local mothers how to make probiotic yogurt. With Hemsworth’s assistance they prepared the new formulation in their community kitchen. HIV/AIDS patients were recruited with the help of student Ruben Hummelen, and randomized to receive the new formulation or a regular yogurt to serve as the control group. Recruitment exceeded expectations and 112 patients enrolled. They received the yogurt for one month on a daily basis and the results showed that those with the lowest immunity that received the new formulation yogurt had their diseasefighting ability significantly boosted. They also had more energy for tackling the challenges of daily life. Funding for this research project has been provided by AFMNet. l