Advance Magazine - Winter 2008/2009

O F F I C I A L P U B L I C AT I O N O F T H E A DVA 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

Volume V Number 1 Winter 2008/09

Partners inpeptides

page10Prof. 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.

INSIDE:

• Consumer food panel page 8

• Encapsulating probiotics page 12

• Yogurt for AIDS relief page 16

Français

au verso

Partners inpeptides

page10

Welcome

3AFMNet – ADVANCE 2009

Welcome to our fifth annual edition of Advance,the official publication of the Advanced Foods andMaterials Network (AFMNet).

AFMNet is Canada’s national food and bio-materials research network. Our researchers arehelping to produce commercially viable, sociallyacceptable, value-added products and processes thatbenefit all Canadians. Partnering with industry,government, not-for-profit organizations andnational and international research institutions,AFMNet’s vision is for a healthier Canada.

In this issue you will find interesting updates onresearch stories from past issues. You will read aboutthe progress that Gregor Reid and his team have madeusing probiotic yogurt to treat patients withHIV/AIDS and other immune deficiencies andmalnutrition; the exciting work being done by LouiseNelson and Peter Sholberg to solve the age-oldproblem of post-harvest fruit loss due to fungal decay;and how Ahmed El-Sohemy and his team haveprovided the first evidence that a variation in theGLUT2 gene plays a role in sugar intake, which helpsexplain individual preferences for high-sugar foods.

We also bring you news of many other projectsof benefit to Canadians. You will see how RotimiAluko (cover) is developing a natural approach toreduce hypertension (high blood pressure) in kidneypatients; how Spencer Henson and John Cranfieldhave created a large-scale consumer network to allow researchers toaccurately track changes in Canadian eating habits and measureconsumer response to issues like food scares; and how Yoshinori Minehas provided the first evidence of the tremendous antioxidantpotential 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 newfaces to our research network and continuing to benefit from theinnovation and insight of many familiar ones. We hope you enjoy thisissue, and encourage you to share it with others. As always, wewelcome your feedback and ideas.

Sincerely,

Chief Research Officer, AFMNet Chair of the Board of Directors, AFMNet

Volume V Number 1 Winter 2008/09

The official publication of the Advanced Foodsand Materials Network

A publication to promote dialogue and understanding about sophisticated foods and materials research across Canada

Executive EditorLouise Jessup

Project Co-ordinatorKaitlyn Little

Project ManagerLise Smedmor

EditorOwen Roberts

Copy EditorStacey Curry Gunn

DesignJnD Marketing

Financial ManagerJan Smith

Address correspondence to:Louise Jessup, Communications Manager

150 Research Lane, Suite 215Guelph, Ontario, Canada N1G 4T2

E-mail: [email protected]

Visit the AFMNet website:www.afmnet.ca

This publication was written by students in theSPARK program, Students Promoting Awareness

of Research Knowledge, at the University of Guelph in Ontario, Canada.

Publications Mail Agreement Number 40064673

Please return undeliverable Canadian addresses to:AFMNet, 150 Research Lane, Suite 215, Guelph,

Ontario, Canada N1G 4T2

Dr. R

ickey Yad

aD

r. Larry M

illigan

Clockwise from right:

Third-year economics student ArpanaChakravarty 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 KaitlynLittle 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.

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.

4 AFMNet – ADVANCE 2009

C O N T R I B U T O R S

Photo by Dave Peleschak


C O N T E N T S

Foods and Health

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

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 16Cover photo by Ian Causland

6

8

16

10


Sugarcraving?Blameyour parentsBy Arpana Chakravarty

People with a genetic variation in agene dubbed GLUT2 – which controlssugar entry into cells – tend to consumemore sugar than those without it, sayUniversity of Toronto researchers.

Prof. Ahmed El-Sohemy, Departmentof Nutritional Sciences, and PhDcandidate Karen Eny are examining thebiological reasons behind people’s foodconsumption behaviours.

“This line of research helps usunderstand why some people, based ongenetics, consume more sugars thanothers,” says Eny.

In their research studies, the teamfound that people with the geneticvariation consumed more sugars, especially

from sweets and sweetened beverages, thanthose without the variation.

Potential confounders such as age, sex,physical activity and BMI did not have animpact on the results.

With the rise of obesity and type-2diabetes, there is growing interest inunderstanding how genetics plays a role inthese diseases, says Eny. The researchershope this study’s findings will provideinsight into the role GLUT2 plays incarbohydrate consumption and how thismay affect diabetes risk, which is linked toobesity.

A number of biological reasons maybe behind people’s food consumptionbehaviours. The research team’s work withGLUT2 suggested this glucose transportermonitors the level of sugar in the blood,to signal the brain to eat or to stop eating.That helps maintain adequate levels ofsugar to fuel our body.

Besides providing energy, sugars canalso enhance mood for some people morethan others. Now the team is investigatingwhether a variation in a gene that affects theactions of dopamine – a mood-alteringchemical that occurs naturally in the brain– explains why some people consume moresugars than others.

For those people, consuming sugarsmight be more related to how it makesthem feel.

This research was funded byAFMNet, the Canadian Institute of HealthResearch and a Julie Payette ResearchScholarship that Eny received from theNatural Sciences and EngineeringResearch Council.

Other collaborators involved in thisstudy are University of Toronto Prof.Thomas Wolever and graduate studentBénédicte Fontaine-Bisson. l

Foods and Health

There’s a new approach emerging to try to solve themystery of Irritable Bowel Disease (IBD), a conditionon the rise in Canada.

Prof. Yoshinori Mine, Department of Food Scienceat the University of Guelph, is examining a peptideisolated from egg yolk that can decrease gutinflammation caused by diseases such as IBD.

This permits the condition to be managed withoutthe adverse side effects that may accompanymedications.

“Just eating eggs won’t help with the symptoms.Dietary interventions are necessary,” says Mine. “Youhave to extract the peptide using an enzyme, and thenconsume it as a supplement to get the health benefits.”

Precision cutting

An egg peptide sliced just rightmay hold the key to treatingIrritable Bowel Disease

By Anupriya Dewan

University of Toronto researchers Prof. Ahmed El-Sohemy and PhD candidate Karen Eny havefound 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.


The jury is still out on the effectivenessand safety of a fatty acid marketed as ahuman weight-loss supplement, although ithas been shown to work in animals.

At the same time that Europeapproved a conjugated linoleic acid (CLA)supplement that claims to help people shedpounds, research emerged in Canadashowing CLA could not be proven topromote weight loss in humans.

Preliminary animal studies werepromising; CLA was shown to be effectivefor reducing weight as well as possessinganti-cancer properties. But the benefitsdon’t seem to transfer to humans.

In fact, CLA may be causing adverse

health effects, says University of Manitobaresearcher Peter Jones.

“An increasing number of clinical trialsshow that CLA is not working, and here itis being approved by the [European]government,” says Jones. “We need tofigure out why it works in animal modelsand not in humans.”

Indeed, findings several years agoresulted in the popularization of CLAsupplements as weight loss agents. Inprevious human studies, a group of patientswere given the CLA supplement and therest were given a placebo. The CLA-ingesting group lost more weight, but a trialconducted by Jones failed to replicate that

data. What caused the weight loss in theoriginal study was – and still is – unknown.

Jones says weight loss may be causedby a state of inflammation caused by CLA.Increased liver mass or inflammation ischaracteristic of a condition known as fattyliver disease (fat being accumulated in theliver), which is caused when the liver isstressed by removing toxins from the blood.

Another suspected reason for thisdiscrepancy between animal models andhumans is the young age of the animals instudies, versus human adults. Animals notfully grown may be using CLA in adifferent way, resulting in the weight loss.

“Public safety needs to be at theforefront of everyone’s mind when we arelooking at food additives. We need to makesure it’s not harmful,” says Jones.

Others involved in this research areProf. Roger McLeod, Dalhousie University;Profs. Spencer Proctor, Catherine Field andDonna Vine, University of Alberta; Profs.Helen Jacques and Andre Marette,University of Laval; Harold Aukema,University of Manitoba; Prof. StephenCunnane, University of Sherbrooke; andDrew Wakefield of the Univerity ofManitoba’s Centre for Functional Foodsand Nutraceuticals.

Funding has been provided byAFMNet, Beef Information Centre,Alberta Agriculture and RuralDevelopment, Dairy Farmers of Canada,Alberta Livestock and Development Fund,National Dairy Council, and theAgricultural Bioproducts InnovationProgram. l

Scientists believe IBD may be causedby stress, lifestyle and diet. The disease ischaracterized by inflammation of thegastrointestinal tract, resulting incramping, abdominal pain, constipationand diarrhea. Other chronic diseases,including diabetes, are linked to IBD,making it a condition with far reachingconsequences. Currently, the only way totreat it is by reducing its symptoms withthe use of steroids, which leads to otherside effects.

Mine has found that the peptide isactivated when its proteins are cut at

specific spots. Once activated, it can helpreduce the inflammation associated withIBD. This activated peptide can be used asa supplement in a variety of products,including juices, or in capsule form.

Supplementation is necessary because,unfortunately, humans can’t convert theprotein from eggs into this beneficialpeptide. Pepsin – an enzyme in the humanstomach that breaks down proteins –doesn’t cut the protein at the spots neededto activate the peptide.

“We want to improve gut health andimmunity to improve lives and prevent

diseases by foods. This way we can developproducts to improve Canadians’ health,”says Mine.

Also involved in this research areUniversity of Guelph Prof. Ming Fan ofthe Department of Animal and PoultryScience, University of Toronto nutritionalscientist Prof. Ahmed El-Sohemy, andRong Cao of Agriculture and Agri-FoodCanada.

Funding for this project has beenprovided by AFMNet. l

New questionsabout fatty-acidsupplement

CLA shows promise in animal studies but needs a closer look for human use

By Anupriya Dewan and Andrea Hruska


Consumer and Ethical Issues

Gaining insight quickly and thoroughly intoCanadian consumers’ perceptions of food –including the acceptability of functional foods andnutraceutical products – is easier and more accuratethanks to a consumer food panel created at theUniversity of Guelph.

The panel, developed by Profs. John Cranfieldand Spencer Henson, Department of Food,Agriculture and Resource Economics, uses bi-monthly online surveys of the same group ofindividuals to better understand consumer views offood, health and agricultural products such asfunctional foods and nutraceuticals.

“Using the panel we are able to see howpeople’s concerns, perceptions and consumptionpatterns of food change over time,” says Cranfield.“Knowing this will allow us to better understandwhat drives consumer acceptance.”

The panel consists of 2,000 Guelphconsumers who are representative of the city basedon their age, education level and gender. Theresearch team chose Guelph specifically, because itspopulation broadly represents the overall Canadianpopulation.

When looking at consumer acceptability offunctional products, researchers have found thatdemographics are irrelevant. Acceptability comesdown to attitudinal and behavioural factors, theysay. Two groups of consumers emerged whenlooking at attitudinal factors: those who are pricesensitive, and those whose acceptance is based solelyon the health and nutrition information of theproduct.

With the price-sensitive group, the nutritionalbenefit had no impact. Decisions to purchase the

product always came back to its price. However, asthe industry develops, product prices will generallystart to come down, Cranfield predicts.

On the flip side, as the reported nutritionalbenefit of the product increased, consumeracceptance followed in the group whose uptake wasbased on health and nutrition information.

When looking at behavioural factors, the panelrevealed that the consumers who are most likely tobuy foods with functional compounds alreadyexhibit healthy behaviours.

The panel also found the meaning of“functional foods” remains unclear to manyconsumers. Cranfield says the industry needs tobetter communicate about these foods andnutraceutical products, especially the mostcommon ones. For example, consumers might notmake the connection that their probiotic yogurtfalls into this category of being a functional food,he says.

With the panel, researchers hope to trackindividuals over time and ask follow-up questionsto see how views and attitudes relate to previousanswers.

“Better understanding consumer acceptancewill allow researchers and industry to developproducts that meet consumer demand,” saysCranfield.

Also involved in this project are post-doctoralresearchers Oliver Masakure and Jose Blandon ofthe Department of Food, Agriculture and ResourceEconomics at the University of Guelph.

This research is funded by AFMNet and theOntario Ministry of Agriculture, Food and RuralAffairs. l

A quick read on Canadian consumersNew research panel reveals views and consumption patterns of functional foods

By Kaitlyn Little

These Enviropigs are anexample of animal

biotechnology. Created atthe University of Guelph,Enviropigs are genetically

modified to better usedietary phosphorus,

reducing surface andground water phosphorus

contamination.

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Investigating the value and ethicalconcerns of animal biotechnology – usingresearch on what stakeholders think aboutspecific applications, including geneticallymodified animals and cloned animals – isthe focus of a new book that combinesstakeholder views with expert opinion. Itwill be published by University of TorontoPress in 2009.

Prof. Sarah Hartley, Department ofPolitical Science, Simon Fraser University,and Prof. Conrad Brunk, Department ofPhilosophy, University of Victoria, securedsix expert researchers to write chapters thatdraw on the results of a series of stakeholderfocus groups. In these groups, the researchersengaged participants to explore theirperspectives on issues raised by animalbiotechnology, says Hartley.

“This approach to research is notsupposed to be representative of the overallCanadian population. Instead it represents aflavour of what stakeholders think about theissues,” says Hartley.

Seven focus groups were conductedwith key stakeholders, including researchscientists, government regulators, farmers,health researchers, health care providers andrepresentatives of alternative agriculture andanimal justice.

During the focus groups, researcherspresented the participants with 10 possibleapplications of animal biotechnology –ranging from cloning bulls for agriculturalpurposes to genetically modifying mice forhuman health research – and askedparticipants to rank their selections from themost supportable to least supportable.

Researchers were not interested in theparticipants’ rankings per se, but used theexercise to understand the values behind therankings and the value tradeoffs that weremade.

The focus groups resulted in someinteresting findings. For example, theyshowed that among the various stakeholdergroups there seemed to be a perceived

hierarchy of being – that is, the closer tohumans the animal ranked on thephylogenetic scale, which measuresrelatedness in terms of common ancestors,the more adverse reaction participants had toa specific animal biotechnology application.An example of this is that applicationsinvolving a mouse or a fish were deemedmore supportable than those using primates.

Another finding was that using animalbiotechnology strictly for economic gain wasnot particularly supportable. For instance,the focus group participants across allstakeholder groups found that goldfish thatglow in the dark (sold as a novelty fish in theU.S.) are frivolous and therefore not easilysupportable.

The book examines these values andethical issues and others in six chapters thatinclude industrialized agriculture, alternativeagriculture, animal justice, health care,health research and religion. Theintroduction and a final chapter that dealswith the regulatory implications of thesefindings will be penned by Hartley andBrunk.

The book also includes two chaptersoutlining the current state of the science ofanimal biotechnology and the ethical issuesrelated to it.

“The hope is that this book willcontribute to the debate on animalbiotechnology and provide information forthose who are interested in seeing a range ofopinions on the issue,” says Hartley.

Chapter authors include MickeyGjerris, University of Copenhagen; PaulThompson, University of Michigan; LyneLetourneau, Laval University; HaroldCoward, University of Victoria; Nola Ries,University of Alberta; Peter Phillips,University of Saskatchewan; and LoriSheremeta, University of Alberta. CecilForsberg, University of Guelph, and DavidFraser, University of British Columbia, arethe scientific advisors for the project.Michelle Illing, Canadian Food InspectionAgency, and Amanda Whitfield, HealthCanada, are the project’s governmentpartners. Other project partners includedKeith Pitts, formally from the Pew Initiativeand Genome BC.

This project is funded by AFMNet. l

Unravelling valuesand ethical concernsaround animalbiotechnology By Kaitlyn Little


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“Inhibiting reninis like cutting off

the head of a giantcalled hypertension.”

- Prof. Rotimi Aluko

Prof. Rotimi Aluko,University ofManitoba, is workingwith pea peptidesthat can reducehypertension andcure kidney disease.

Pea peptides fight hyper-tension and kidney diseaseBy Anupriya Dewan

Pea proteins that have been hydrolyzed and split into smallerpieces called peptides have been shown to combat kidney diseaseand hypertension, say researchers at the University of Manitoba.

Prof. Rotimi Aluko, Department of Human NutritionalSciences, says pea peptides provide relief for hypertension in twoways. They block renin, the root cause of increased blood pressurefound early on in the biochemical pathway, and they reduce kidneydisease progression.

Current medications target Angiotensin Converting Enzyme(ACE), which amplifies the effects of renin, making it a less effectivemethod of curing the kidney disease.

The body regulates blood pressure using a variety ofcompounds, including renin, by changing the diameter of bloodvessels. Renin increases blood pressure by producing a compoundthat helps blood vessels contract. But if excess renin is released,blood vessels contract more than they should, increasing bloodpressure to dangerous levels. ACE normally amplifies renin’s effectand makes the problem worse.

“Inhibiting renin is like cutting off the head of a giant calledhypertension. It can’t be a problem anymore,” says Aluko. “BlockingACE is like cutting off an arm or a leg. The giant still lives.”

The isolated pea peptides block renin’s activity, which preventsthe blood vessels from contracting excessively. With the bloodvessels dilated, the blood pressure remains normal because there ismore space for blood to flow through. With little renin activitypresent, there’s also no amplification due to ACE, solving theproblem at its root.

As a result, these peptides are more effective at treatinghypertension than drugs on the market today, because medicationstarget ACE, not renin.

The isolated peptides also increased cyclooxygenase 1 (COX1)levels, which is known to reduce inflammatory agents released bythe kidney. Reduced inflammation improves kidney function andreduces 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 causeof the problem for the first time, but the work isn’t done yet. Alukoplans to do clinical studies to measure the impact of the peptides onhumans.

“Curing hypertension may become as easy as drinking juice ortaking 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, theNatural Sciences and Engineering Research Council and theManitoba Centre of Excellence Fund. l


Materials

Get-well gelAntimicrobials could be anew remedy for bacterialinfections

By Hayley Millard

Experience has shown that naturally occurring antimicrobialscan effectively fight off bacterial infections. However, many ofthese compounds are highly reactive and rapidly break downbefore they actually come in contact with undesirable bacteria. Ifresearchers could find a way to overcome this obstacle,antimicrobials could become a more practical treatment forbacterial infections than antibiotics, where overuse can produceantibiotic-resistant bacterial infections.

Prof. Dérick Rousseau, Ryerson University, and Prof. AllanPaulson, Dalhousie University, are working with allylisothiocyanate (AITC) – a highly water-soluble antimicrobial.Although AITC can effectively suppress bacterial growth, it reactswith other compounds in the body before encountering the actualproblem: harmful bacteria.

Rousseau and Paulson want to harness this compound so itwill react only at the site of the infection. And they say rigid gelstructures called hydrogels are the answer.

Encapsulating antimicrobial compounds such as AITC in gelcapsules that could be swallowed, or in gel patches that could beplaced 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’ expansionrate controls how quickly the compound within the gel is released.Rousseau and Paulson are experimenting with the hydrogel’sintricate formation to control the size of the gel’s pores and howthey expand when gel swells.

“We’re looking at controlling the rate of diffusion for a slow,timed release of the encapsulated compound,” says Rousseau. “Ifthe pores are too small, not enough of the antimicrobialcompound will pass through, but if the pores are too big, toomuch will pass through too quickly.”

Others involved in the research include Profs. MichaelNickerson of the University of Saskatchewan; GianfrancoMazzanti and Lisbeth Truelstrup Hansen of Dalhousie University;Pascal Delaquis of Agriculture and Agri-Food Canada; andphysicist David Pink from St. Francis Xavier University.

This research is funded by AFMNet. l

Researchersare looking atnew techniquesfor better colonhealth

By Matthew DiCicco

Probiotics – sometimes called “helpful”bacteria – are said to reduce colon cancer,increase mineral absorption and out-compete harmful bacteria. Researchers at theUniversity of Saskatchewan are exploringnew ways to help probiotics get to the large

intestine safely, and to flourish there.Some good bacteria naturally inhabit

the colon. However, they can’t prosperwithout a proper diet and help fromprebiotics – food ingredients that stimulateprobiotic growth, helping to crowd out badbacteria such as Escherichia coli.

That’s where Prof. Nicholas Low andhis research team at the Department of Foodand Bioproduct Sciences come in. They’reconducting research on how to effectivelycombine and encapsulate prebiotics andprobiotics for transport and delivery to thelarge intestine.

“This research could be of significanthealth benefit to people everywhere,” Lowsays.

The project’s main focus is to findappropriate oligosaccharides – carbohydratesfound naturally in many plants – to use asprebiotics, and to determine how they affectprobiotic growth. Oligosaccharides makegood prebiotics because they’re a superbcarbon source for probiotics, and are notutilized well by harmful bacteria. Theyusually escape digestion in the smallintestine and make it to the colon wherethey can support the growth of “helpful”bacteria.

Most probiotics found in food aremainly in yogurt and other cultured dairyproducts. Typically, they are killed by thestomach’s harsh acidic environment, bycommon food processing techniques, or byboth. The stomach is designed to kill offbacteria, good or bad, so the researchers arelooking to find an efficient balance ofprebiotics and probiotics that they canencapsulate to reach the right spot in theintestines.

Encapsulation is an importantcomponent of the research. Without properprotection, the probiotics will die in thestomach en route to the large intestine, ortravel past the colon without disintegrating.Encapsulation with a suitable protein couldhelp the compound to bypass the stomachand disintegrate at the correct time and placeleading to maximum health benefits.

In the future, this multi-componentmaterial will be employed as a foodingredient to produce functional foods withthe goal of targeted delivery in human andanimal digestive systems.

Right now, however, getting the threecomponents working together effectivelywill be a big achievement on its own.

“It is a significant scientific endeavor toget these three components workingtogether,” says Low.

Others involved in this research projectare Profs. Michael Nickerson and DarrenKorber, Department of Food andBioproduct Sciences, University ofSaskatchewan.

Funding for the research is provided by AFMNet, the Saskatchewan AgriculturalDevelopment Fund and Bioriginal Food &Science Corporation. l


Materials

Beneficialbacteriaease intestinalills

ThesenaturalproteinsCAP diseaseBy Arpana Chakravarty

Bacterial food-borne illnesses pose athreat to food supply. In addition, there is aneed to extend the shelf life of foods.Dalhousie and St. Francis Xavier universityresearchers are hoping to improve thesituation with anti-bacterial proteins.

All living organisms are equipped withsmall innate protein molecules that naturallyfight bacteria, known as CationicAntimicrobial Peptides (CAPs). Finding outhow CAPs enter bacteria will allowresearchers to better understand how thesepeptides work to destroy disease-causing andspoilage-promoting bacteria.

Prof. Tom Gill at Dalhousie’sDepartment of Process Engineering andApplied Science is looking at how CAPsinhibit Gram-negative bacteria – a group ofbacteria with a unique cell membranestructure.

“CAPs are part of Mother Nature’snatural defense,” says Gill. “They’re builtinto every living organism, so why not usethem to preserve our food?”

CAPs have a unique ability to enter anddestroy bacteria. Gill is testing to see if andhow peptides enter through porins – barrel-shaped proteins on a bacterial cell’s outermembrane that allow nutrients and wastes inand out of the cell – so he can mimic theporins’ structure and develop a successfulsynthetic version to use in food.

Gill extracts protamine, a type of CAP

naturally found in herring, and purifies it.Then, his colleagues separate the porinsfrom the bacteria and insert them into anartificial cell wall to observe protamine’schief method of entry.

Part of this multidisciplinary approachinvolves Prof. David Pink, a theoreticalphysicist at St. Francis Xavier University.Pink predicts molecular behaviour usingmathematical modeling and computersimulations. His coworkers can then verify the outcomes experimentally orpredict and understand new experimentalmeasurements.

To deliver peptides to the intended siteof attack, researchers have been trying todesign a platform for delivering CAPs withbarrel-like porins so the peptides won’t bedigested by bacterial enzymes orunintentional targets upon entry. Pinkdeveloped a mathematical model andcomputer simulation for the proposeddelivery system. Although this system stillneeds to be tested in the lab, his results lookpromising.

“We are cautiously optimistic that wemight have come up with a delivery vehiclethat will deliver the CAP to bacterialsurfaces,” says Pink.

Research shows long-term treatmentwith CAPs doesn’t produce the same type ofbacterial resistance as other antimicrobialcompounds, including penicillin. Bacteriaare gaining resistance to conventional

treatment options, a serious problem thatCAPs may solve.

The results from this project may leadto the development of new antimicrobials(drugs that kill or prevent the growth ofmicrobes, including bacteria, fungi andviruses) and, perhaps in the future, betterantibacterial compounds for the healthsector.

“We are addressing a problem that boththe health sector and food industry arestruggling with,” says Pink.

This research is funded by AFMNet,the Natural Sciences and EngineeringResearch Council and the AtlanticInnovation Fund. Others involved in thisresearch include Prof. Erich Sackmann,Technical University of Munich, and Prof.Motomu Tanaka, Heidelburg University.The late Terry Beveridge, Department ofMolecular and Cellular Biology at theUniversity of Guelph, was also involved inthe study. l


Protamine, a CationicAntimicrobial Peptide (CAP),

naturally found in herring, wasused by researchers to discoverhow the peptide kills bacteria.

Researchers can use thisknowledge to create a synthetic

version to use in foodpreservation.

Eduardo Luzzatti Buyé

Engineering plants resistant to commondiseases will help increase crop productivity, saysan AFMNet member.

Dr. Ravinder Kumar of the University ofVictoria says his work will help alleviate the risingdemand for food that will accompany an increasein population.

“Food scarcity can become a major issue ifadequate measures are not taken now. So, it’snecessary to have an appropriate technology toprotect our yields…and we have [it],” he says.

Kumar’s research group is working withtypes of proteins that naturally fight diseases,called antimicrobial peptides (AMPs). Theresearchers have inserted peptides into severalspecies of plants to make them resistant to adiverse group of pathogens, including mycotoxicfungi, which pose serious food safety issues.

The peptides are collected from a variety ofsources, including frogs and insects, which live ina challenging environment and have a naturalability to prevent infection.

Peptides are made under the direction of agene, so once the target peptide is identified, itsgene is then transferred to plants. The resultingtransgenic plants are tested rigorously against aspectrum of pathogens.

Augmenting plants’ natural immunity is aneco-friendly alternative to using pesticides, saysKumar. “Unlike other ways of incorporatingresistance in plants that are associated with pooryield, we are glad to say that this technologyincreases plant productivity by 15-20 per cent evenin the absence of diseases,” he says. “Thistechnology has an added advantage of preventingfield and storage losses while providing safer food.”

Currently, the group is working towardsturning the gene on only whenever and whereverit’s required. The approach would alleviate theconcerns of those who are wary of transgeniccrops.

“I believe that this research is importantbecause, as the world population is growing,arable land is shrinking, meaning there is morepressure for field productivity. If we have acertain technology developed, we can use itanytime. We may not need it now, but we mustthink down the road when the traditional way ofdoing agriculture is not sufficient,” says Kumar.

Next, Kumar plans to conduct field studiesin India.

Dr. Kumar’s group is headed by Prof.Santosh Misra, Department of Biochemistry andMicrobiology, University of Victoria. Alsoinvolved in this research is Dr. DmytroYevtushenko of the university’s Department ofBiochemistry and Microbiology.

This research is funded by AFMNet. l



Using peptidesto protect yieldsBy Arpana Chakravarty

Antimicrobial peptides --natural disease-fightersfound in frogs and insects --are inserted into plants byDr. Dmytro Yevtushenko and Dr. Ravinder Kumar,University of Victoria, tocreate illness-resistanttransgenic plants.

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When apples on trees are exposed to fungalpathogens, post-harvest rot can occur duringstorage. This problem costs the apple industry five to10 per cent a year in crop losses. Now, researchers atthe University of British Columbia have developed atwo-pronged approach to protect apples from thesepathogens. Their method combines on-sitepathogen detection and the use of an organicbiological control agent that is applied to protectexposed apples.

Prof. Louise Nelson, Department of Biologyand Physical Geography, and her research team havedeveloped a DNA-based macroarray technology thatallows detection of the three most prevalentpathogens (blue mould, grey mould and mucor)from samples of the air, leaves and blossoms in anorchard during the growing season.

They have also developed several soil bacterialisolates for use as an organic biological control agentto protect the apples from rotting while in storage.

“Our goal is to develop new economicalmethods for the detection and control of fungalpathogens,” says Nelson.

After the first field trial, researchers found thatthe soil bacterial isolates were effective in protectingthe apples for the first three months of cold storage.The team will now study the survival of the isolateson apples during storage beyond three months, animportant health and regulatory consideration priorto commercialization of the product.

Next, the researchers will use the DNAmacroarray technology to try to determine therelationship between weather and factors such as leafwetness, a pathogen’s presence at blossom and fruitset, and the incidence of disease during storage.They hope to develop a prediction model that willassist growers in determining the probability ofdisease occurring during storage.

Others involved in this research are post-doctoral researcher Danielle Hirkala and graduatestudent Daylin Mantyka from the University ofBritish Columbia and Peter Sholberg of Agricultureand Agri-Food Canada’s Pacific Agri-Food ResearchCentre.

This project is funded by the AFMNet. l


Rot stops hereBy Kaitlyn Little

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.

Tim

Swanky

Nausea, decreased immunity anddiarrhea are some of the side effects manyHIV/AIDS patients experience every day,especially as their immune systemweakens. Fortunately, many side effectsmay be eased or potentially eradicatedwith daily consumption of a newlyformulated, micronutrient-supplementedprobiotic yogurt, say researchers at theLawson Health Research Institute.

Prof. Gregor Reid, University ofWestern Ontario Department ofMicrobiology and Immunology, andJaimie Hemsworth, a MSc student fromBrescia College, have recently finishedtesting micronutrient-supplementedprobiotic yogurt – a regular yogurt withLactobacillus rhamnosus GR-1 and a rangeof micronutrients added.

“We modulate our health in manyways through the food we eat,” says Reid.“The bacteria inside us play a huge role inour very existence.”

Probiotics improve immunity in anumber of ways, including by signallingthe T-cells – a type of white blood cell thatattacks invaders – to begin working.

In HIV/AIDS patients, the depletionof their immune system (measured by alowering of their CD4 cell count) makesthem highly susceptible to commonviruses such as the flu, pneumonia and

the common cold, and harmful bacteria. In the spring of 2008, Hemsworth

performed a pilot study at the HIV Clinicin London, Ontario that showed themicronutrient-supplemented probioticyogurt had potential to improve the well-being of HIV patients. She then travelledto Africa to the Lawson research site at theNational Institute for Medical Researchin Tanzania to determine if the conceptcould help AIDS patients there.

A program called Western HeadsEast had already taught local mothershow to make probiotic yogurt. WithHemsworth’s assistance they prepared thenew formulation in their communitykitchen. HIV/AIDS patients wererecruited with the help of student RubenHummelen, and randomized to receivethe new formulation or a regular yogurt to serve as the control group.Recruitment exceeded expectations and112 patients enrolled. They received theyogurt for one month on a daily basis andthe results showed that those with thelowest immunity that received the newformulation yogurt had their disease-fighting ability significantly boosted.They also had more energy for tacklingthe challenges of daily life.

Funding for this research project hasbeen provided by AFMNet. l



Yogurt with a differenceHIV/AIDS patients can benefit from eating micronutrient-supplementedprobiotic yogurt

By Andrea Hruska

Consuming micronutrient-supplemented probiotic yogurt cangreatly reduce AIDS side effectssuch as nausea, decreasedimmunity and diarrhea.

Ina

Pete

rs

Advance Magazine - Winter 2008/2009

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Transcript of Advance Magazine - Winter 2008/2009