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Validation Of A Fluorescence-Based Bacteria Enumeration And Viability Determination Method Using Image Cytometry, Matthew R. Hodgkin Dec 2019

Validation Of A Fluorescence-Based Bacteria Enumeration And Viability Determination Method Using Image Cytometry, Matthew R. Hodgkin

Electronic Theses and Dissertations

Craft beer production in the United States has been increasing significantly in recent years. As production and participation in the industry increases, so have consumer demands for more beer options. Breweries have met this call with experimentation of ingredients in their beer and also the styles they brew. One such beer, the sour beer, is an example of this experimentation and new product development. Sour beers are a style that differ from most other beers by how they are manufactured. Instead of being fermented with only yeast, both a lactic acid-producing bacteria and yeast are used. With increased competition amongst ...


Microbial Diversity Of The Symbiotic Colony Of Bacteria And Yeast (Scoby) And Its Impact On The Organoleptic Properties Of Kombucha, Danielle L. St-Pierre Aug 2019

Microbial Diversity Of The Symbiotic Colony Of Bacteria And Yeast (Scoby) And Its Impact On The Organoleptic Properties Of Kombucha, Danielle L. St-Pierre

Electronic Theses and Dissertations

Kombucha is an effervescent fermented tea beverage that is gaining popularity for its probiotic nature and purported health benefits. The market for kombucha is expected to reach $1.8 billion by the year 2020. The composition of microbes that compose the symbiotic colony of bacteria and yeast (SCOBY) is highly variable with some species commonly found from the Gluconobacter, Acetobacter, Zygosaccharomyces, Saccharomyces, and Schizosaccharomyces genera.

It was hypothesized that different SCOBYs, obtained from different sources would vary in microbial diversity and produce different biochemical and flavor profiles in the resulting beverage over several generations. Kombucha is a fermented product and ...


Efficacy Of Alternative Sanitization Methods On Wild Blueberries And Fresh Cut Cantaloupe, Selena Callahan Aug 2019

Efficacy Of Alternative Sanitization Methods On Wild Blueberries And Fresh Cut Cantaloupe, Selena Callahan

Electronic Theses and Dissertations

In the last decade, outbreaks linked to the consumption of contaminated fresh produce have increased mitigation efforts to minimize the risks associated with these products. Due to the lack of a kill step during processing of ready-to-eat (RTE) foods, good manufacturing practices (GMP’s), and sanitization are the key prevention areas most commonly used to control these risks. Many factors must be considered by processors for successful intervention such as sanitizer type, method of application, duration of application, and concentration. Additionally, product considerations such as water content, pH, and bacterial harborage sites can contribute greatly to how effective an applied ...


Effects Of Salt Concentration On The Physicochemical Properties And Microbial Safety Of Spontaneously Fermented Cabbage, Surbhi Khanna May 2019

Effects Of Salt Concentration On The Physicochemical Properties And Microbial Safety Of Spontaneously Fermented Cabbage, Surbhi Khanna

Electronic Theses and Dissertations

Fermented foods, including sauerkraut, have gained consumer popularity due to an increased awareness of reported health benefits associated with probiotics. Sauerkraut is typically produced at 2−3% salt concentrations or higher, which helps to reduce the growth of pathogenic and spoilage microorganisms. The FDA has recently issued guidance to the food industry to voluntarily reduce sodium in products due to health concerns associated with high sodium consumption. Therefore, interest in lower salt fermented foods may increase. However, information on quality and safety of lower sodium sauerkraut is limited. Two separate studies were conducted to evaluate the physicochemical properties and quality ...


Safety Assessment Of Hydroponic Closed System, Adwoa S. Dankwa May 2019

Safety Assessment Of Hydroponic Closed System, Adwoa S. Dankwa

Electronic Theses and Dissertations

The hydroponic system is an increasing sector for horticultural production. It is used mostly for fruit and vegetable production. Lettuce (Lactuca sativa) is one of the most cultivated types of produce in the hydroponic system. It runs on nutrient solution and in some cases substrates. Water serves as the backbone for hydroponic production, mainly utilized for nutrient solution preparation. Substrates are sometimes added to provide support for plants root systems. Selection of substrate depends on the type of crop and the availability of the substrate. A good substrate should be able to balance the oxygen - water ratio around the root ...


Broth: Enhancing Market Opportunities And Improving Sustainability Of Maine Farmed Seaweed, Zachary M. Bonelli Aug 2018

Broth: Enhancing Market Opportunities And Improving Sustainability Of Maine Farmed Seaweed, Zachary M. Bonelli

Electronic Theses and Dissertations

Seaweed is becoming popular across the world as consumers learn about the variety of seaweed-based products and their health benefits. Sugar kelp is one of Maine’s seaweed varieties that is locally grown each year. Sugar kelp and similar species contain many useful nutrients including iodine, calcium, magnesium, iron, and vitamins A, B, C, and E. Even though the health benefits of seaweed have been proven, locally-sourced seaweed has not yet become any more popular in Maine. Part one of this study identified suitable processing steps for a sugar kelp-based broth. Part two assessed how consumers’ demographics and food neophobia ...


Development Of Kefir Products Using Aronia Or Elderberries And The Impacts Of Fermentation On The Health-Promoting Characteristics Of Aronia Polyphenols, Xue Du Aug 2018

Development Of Kefir Products Using Aronia Or Elderberries And The Impacts Of Fermentation On The Health-Promoting Characteristics Of Aronia Polyphenols, Xue Du

Electronic Theses and Dissertations

Diabetes is a global health problem. The consumption of dietary polyphenols may help to decrease the risk of type 2 diabetes and slow the progression of diabetic complications. Aronia (Aronia melanocarpa) and elderberry (Sambucus nigra L. ssp. canadensis) fruits are rich in polyphenols and exhibit health-promoting properties, but they are underutilized. Aronia and elderberries are rarely consumed raw due to the astringent mouth feel. New food products are needed to increase their consumption. Kefir, a fermented dairy beverage, was chosen to be the matrix for incorporating berries due to: 1) the protein matrix can help mask the astringency; 2) an ...


Flower Visitation In Relation To Pollen And Nectar Nutrition: Implications For Pollinator Habitat And Conservation, Megan E. Leach Aug 2018

Flower Visitation In Relation To Pollen And Nectar Nutrition: Implications For Pollinator Habitat And Conservation, Megan E. Leach

Electronic Theses and Dissertations

Pollination of both wild and crop plants is at a crossroads; honey bee populations are experiencing losses at a higher rate than ever before, and some native bee species are declining in abundance to the point of being listed as endangered species. A few examples of these threats include pesticide exposure, habitat loss, and climate change. In response to bee population declines, conservation efforts have been initiated to increase habitat quality for bees by planting pollinator reservoirs or gardens. Plants provide nutrition to bees in the form of pollen and nectar. Several studies have shown links between higher nutritional quality ...


The Effect Of Wild Blueberry Anthocyanins And Phenolic Acids On Innate Immunity: The Compliment System, Vasiliki Papakotsi Aug 2018

The Effect Of Wild Blueberry Anthocyanins And Phenolic Acids On Innate Immunity: The Compliment System, Vasiliki Papakotsi

Electronic Theses and Dissertations

Ingestion of berries containing polyphenols is associated with lower risk of inflammatory, metabolic, cardiovascular and degenerative diseases. Diet has been shown to modulate the activation of the complement system, a set of over 50 proteins present in the circulation and tissues that reacts in response to damage or microbial encounter and is critical for the maintenance of homeostasis. Imbalanced activation is tightly correlated with inflammation and various pathologies. Wild blueberries are a rich source of anthocyanins and phenolic acids, which can be found in plasma shortly after consumption. Given the involvement of both complement and polyphenols in the modulation of ...


Development And Shelf Life Evaluation Of A Novel Fermented Seaweed Sauerkraut Utilizing Commercially Important Maine Seaweeds, Sarah M. Brochu Aug 2018

Development And Shelf Life Evaluation Of A Novel Fermented Seaweed Sauerkraut Utilizing Commercially Important Maine Seaweeds, Sarah M. Brochu

Electronic Theses and Dissertations

Fermented vegetables can provide consumers with important health benefits, particularly due to the presence of probiotics. These fermented products have gained popularity with American consumers over the past decade. Therefore, a lacto-fermented seaweed sauerkraut, containing seaweed and cabbage, was developed to address this trend and to create a value-added seaweed product with extended refrigerated shelf life. The objective of this study was to evaluate the effects of kelp species and seaweed incorporation level on the fermentative success, microbial safety, consumer acceptability, and refrigerated shelf life of seaweed sauerkraut for 60 days post inoculation.

Six treatments with varying levels (25%, 50 ...


Extraction And Purification Of (E)-Resveratrol From The Bark Of Maine's Native Spruces, Panduka S. Piyaratne May 2018

Extraction And Purification Of (E)-Resveratrol From The Bark Of Maine's Native Spruces, Panduka S. Piyaratne

Electronic Theses and Dissertations

Resveratrol is a plant secondary metabolite which protects plants from pathogenic invasions and acts as a remedial agent against injury, stress, and tissue damage by UV radiation. With its characteristic stilbene structure, resveratrol adopts (E) and (Z) isomeric forms. However, the (E) isomer is the most biologically active and abundant form of resveratrol in nature.

(E)- Resveratrol confers a variety of benefits to human health and well-being. Besides its antioxidant activity, the role of (E)-resveratrol as an anti-inflammatory, anti-aging, cardioprotection, and anticancer agent has been a widely explored research interest. Many plant species including mulberry, peanut, and grape are ...


Detrital Protein Contributes To Oyster Nutrition And Growth In The Damariscotta Estuary, Maine, Usa, Cheyenne M. Adams May 2018

Detrital Protein Contributes To Oyster Nutrition And Growth In The Damariscotta Estuary, Maine, Usa, Cheyenne M. Adams

Electronic Theses and Dissertations

Oyster aquaculture is an expanding industry that relies on identifying and utilizing natural estuarine conditions for the economically viable production of a filter-feeding crop. The eastern oyster, Crassostrea virginica, is the principal species currently cultured in Maine. In addition to preferentially consumed phytoplankton, various detrital complexes (non-algal and/or non-living organic matter) may provide some nutrition to C. virginica between times of phytoplankton abundance. Here I investigated the importance of detrital proteins in supporting the growth of oysters cultured in the upper Damariscotta Estuary. Oyster aquaculture in this area is highly successful and previous reports indicate that labile detrital protein ...


Attenuating The Antibody Reactivity Of The Shrimp Major Allergen (Tropomyosin) Using Food Processing Methods, Adeseye Lasekan Aug 2017

Attenuating The Antibody Reactivity Of The Shrimp Major Allergen (Tropomyosin) Using Food Processing Methods, Adeseye Lasekan

Electronic Theses and Dissertations

Shrimp is one of the major causes of adverse allergic reactions in both adults and children. Consumers with shrimp allergy have an immune system that is hypersensitive towards certain proteins in shrimp. The immune system of these consumers produces an antibody, immunoglobulin E (IgE), which binds to specific regions on these proteins and activates reactions leading to adverse symptoms. Most shrimp allergic consumers have IgE that binds to a shrimp myofibrillar protein known as tropomyosin. Other than avoidance of shrimp, structural modification of shrimp tropomyosin using food processing methods could influence the capacity of this allergenic protein to bind IgE ...


Refrigerated Shelf Life Evaluation And Effects Of Minimal Processing On Antioxidant Capacity Of Fresh Sea Vegetables From New England, Dhriti Nayyar Aug 2016

Refrigerated Shelf Life Evaluation And Effects Of Minimal Processing On Antioxidant Capacity Of Fresh Sea Vegetables From New England, Dhriti Nayyar

Electronic Theses and Dissertations

Sea vegetables (also known as seaweeds) are gaining popularity among American consumers as a new superfood. Some sea vegetable farmers in New England have begun to distribute fresh or minimally processed sea vegetables to local restaurants and to retail distributors. However, limited knowledge about quality loss and processing effects on fresh, farm-raised sea vegetables postharvest obstructs the growth of a vibrant sea vegetable industry. The objectives of this research were to: 1) evaluate the quality changes and shelf life of four fresh sea vegetables species - dulse, Gracilaria, sugar kelp and winged kelp - during refrigerated storage, 2) determine the basic nutritional ...


A Competitive Assessment Of Commercial Elderberry (Sambucus Sp.) Products And The Evaluation Of Copigmentation Within Elderberry Tinctures, Joseph A. Galetti Phd May 2016

A Competitive Assessment Of Commercial Elderberry (Sambucus Sp.) Products And The Evaluation Of Copigmentation Within Elderberry Tinctures, Joseph A. Galetti Phd

Electronic Theses and Dissertations

Elderberry (Sambucus sp.) fruit is a healthful food with a variety of reported curative properties and is among the richest sources of anthocyanic pigmentation, which are the primary factors for its commercial use. Although a variety of value-added elderberry products are available to consumers, it is questionable as to which product form contains the highest nutrient levels and color stability characteristics, and represents the best value to consumers. It was the objectives of this research to evaluate a variety of commercial elderberry products, and to develop a value-added elderberry product with enhanced nutrient and color stability.

The first part of ...


Improving Extraction Of Allergenic Soy Proteins From Soy Products, Amma Konadu Amponsah Dec 2015

Improving Extraction Of Allergenic Soy Proteins From Soy Products, Amma Konadu Amponsah

Electronic Theses and Dissertations

With recent increase in the utilization of soy proteins, there are mounting concerns of the escalation of soy allergies. It is, therefore, important to improve current methods of allergen detection to ensure accurate labeling of foods, produce more reliable and representative results in studies to create hypoallergenic food and establish allergen thresholds. The conditions used to extract proteins from foods are important determinants for appropriate detection and interpretation of the allergenicity of food materials. The extraction of soy proteins for soy allergen detections is conventionally performed with phosphate buffered saline (PBS) buffer for an extraction period of at least 2 ...


Method Development For Vitamin C Quantification In Two Complex Matrices, Hannah D. Hutt Aug 2015

Method Development For Vitamin C Quantification In Two Complex Matrices, Hannah D. Hutt

Electronic Theses and Dissertations

The following liquid chromatographic (LC) method developments and applied research studies were done using two complex food matrices, potatoes and elderberries, which are common to the state of Maine. Potatoes are Maine’s largest agricultural crop, a staple food in most U.S. households, and are, from an analytical standpoint, considered a complex matrix due to the high starch content that can be difficult to remove without degrading or removing nutrients in the process. Elderberries are an emerging crop in the U.S. because of their antioxidant and anti-viral properties and are found growing wild, throughout Maine. Elderberries are also ...


Effects Of High Pressure Processing On The Quality Of Farm-Raised Abalone (Haliotis Rufescens), Brianna H. Hughes May 2014

Effects Of High Pressure Processing On The Quality Of Farm-Raised Abalone (Haliotis Rufescens), Brianna H. Hughes

Electronic Theses and Dissertations

High pressure processing (HPP) is a non-thermal method used to increase food safety and shelf-life. HPP has been explored for meat tenderization, with conflicting results depending on rigor status during HPP. In the seafood industry, HPP is used to shuck oysters and lobsters, but has been minimally investigated for use in processing abalones. Abalones are shellfish with high perishability that are typically sold live or frozen in the U.S. HPP has been proposed as an alternative method to process shucked abalone meats. The objectives of this research were to evaluate the effects of 1) rigor status during HPP on ...


The Effect Of Wild Blueberry Consumption On The Inflammatory Response, Oxidative Stress And Dna Damage Associated With Exercise, Taylor K. Bloedon Dec 2013

The Effect Of Wild Blueberry Consumption On The Inflammatory Response, Oxidative Stress And Dna Damage Associated With Exercise, Taylor K. Bloedon

Electronic Theses and Dissertations

At all levels of intensity and duration, exercise is known to cause an increase in the generation of reactive oxygen species (ROS). When derivatives of oxygen occur and exist independently with one or more unpaired electrons they are known as “free radicals” (Halliwell and Gutteridge 2007). Since atoms possess electrons that are usually associated in pairs, free radicals have the potential to act negatively in the body. Reactive oxygen species refer to oxygen-centered radicals as well as nonradical but reactive derivatives of oxygen (Halliwell and Gutteridge 2007). When ROS are created in excess, resulting in the disruption of the pro-oxidant ...


Mechanical Processing Of European Green Crab (Carcinus Maenas), The Development Of A Value-Added Product And The Use Of Restructuring Additives To Increase The Functional Properties Of Green Crab Patties, Joseph A. Galetti Dec 2010

Mechanical Processing Of European Green Crab (Carcinus Maenas), The Development Of A Value-Added Product And The Use Of Restructuring Additives To Increase The Functional Properties Of Green Crab Patties, Joseph A. Galetti

Electronic Theses and Dissertations

The European Green Crab (Carcinus maenas) has proven to be a successful invasive predator and has potential to be a valuable food source for human consumption. Due to the small size of green crab, hand picking commercial operations are not feasible. The objectives of this research were to develop uses for this undervalued resource by examining mechanical separation techniques of mince meat; developing a consumer acceptable mince meat product and exploring the functionality of green crab mince meat with additions of restructuring additives. The first part of this research was designed to determine how boil versus steam thermal processing, large ...


Assessing Sleep Quality In Young Adult College Students, Aged 18 - 24 In Relation To Quality Of Life And Anthropometrics, Douglas Mathews May 2010

Assessing Sleep Quality In Young Adult College Students, Aged 18 - 24 In Relation To Quality Of Life And Anthropometrics, Douglas Mathews

Electronic Theses and Dissertations

Little is known about the impact of sleep on quality of life and anthropometrics in young adults. College students (n=218) were recruited through a variety of methods for a study on weight management for obesity prevention and randomized into control (n=108) or treatment (n=110) groups. Of those, 152 (71%) completed pre- and post-tests, including the Pittsburg Sleep Quality Index (PSQI), scored 0-4 =normal and 5-21=disordered, (a=0.80), the General Health Questionnaire-12 (GHQ), scored from 0-14=good quality of life to 15-36=poor quality of life, (ct=0.87), and anthropometrics. Statistical analyses included linear regression ...


Analysis Of Melamine And Cyanuric Acid By Liquid Chromatography With Diode Array Detection And Tandem Mass Spectrometry, Byungchul Kim May 2009

Analysis Of Melamine And Cyanuric Acid By Liquid Chromatography With Diode Array Detection And Tandem Mass Spectrometry, Byungchul Kim

Electronic Theses and Dissertations

Melamine and cyanuric acid are the compounds that caused the global incidences of kidney related disease to pets and infants in North America and China during the last two years. After a concerted research effort by U.S. laboratories, it was discovered that they were intentionally added in raw ingredients to pet foods or milk to increase nitrogen levels without providing protein. Melamine and cyanuric acid can easily combine by hydrogen bonding and produce a melamine-cyanurate complex that directly caused renal failure to pets and infants who consumed the tainted pet food or milk. Many analytical methods for the determination ...


The Effect Of Wild Blueberries On Endothelium-Dependent Vasodilation In Spontaneously Hypertensive Rats, Aleksandra S. Kristo Aug 2008

The Effect Of Wild Blueberries On Endothelium-Dependent Vasodilation In Spontaneously Hypertensive Rats, Aleksandra S. Kristo

Electronic Theses and Dissertations

The effect of wild blueberries on major endothelium-dependent vasodilation pathways and arterial blood pressure (BP) was examined in the young adult Spontaneously Hypertensive rat (SHR), used as a model of endothelial dysfunction, and the Wistar Kyoto (WK) rat, with functional endothelium, used as the control. Male SHR and WK rats were fed a control (SHR-C and WK-C), or a wild blueberry-enriched (SHR-B and WK-B) diet for nine weeks. By the age of 21 weeks, thoracic aortae were excised and 3mm arterial rings were prepared and immersed in Radnoti tissue baths. Rings were precontractred with phenylephrine (Phe) (10"6M), followed by ...


Serum 25-Hydroxyvitamin D Response To Daily Oral Supplementation With 800 Iu Cholecalciferol In Premenopausal Women Living In Maine, Monica Nelson Dec 2007

Serum 25-Hydroxyvitamin D Response To Daily Oral Supplementation With 800 Iu Cholecalciferol In Premenopausal Women Living In Maine, Monica Nelson

Electronic Theses and Dissertations

The purpose of this research was to measure the serum 25-hydroxyvitamin D [25(OH)D] response to daily supplementation with 800 IU vitamin D3 during winter in premenopausal women living in Maine, and to examine the effects of body composition and hormonal contraceptive use on baseline serum 25(OH)D levels and the response to supplementation. One hundred twelve women (22.2±3.7 years old) received placebo from March 2005 until September 2005 when they were randomized to receive either placebo or 800 IU vitamin D3 through February 2006. Eighty-six women completed the study. Body composition was measured by ...


Development Of A Soy-Blueberry Burger And The Changes In Anthocyanins And Phenolics During Storage And Broiling, Pamela Beth Small Aug 2007

Development Of A Soy-Blueberry Burger And The Changes In Anthocyanins And Phenolics During Storage And Broiling, Pamela Beth Small

Electronic Theses and Dissertations

Blueberries are high in phenolic acids and flavonoids, which make them one of the leading sources of antioxidants. When added to foods, antioxidants can increase shelf life, maintain nutritional quality, and retard production of heterocyclic amines in meats during cooking thus having the potential to be of great significance to the food industry. Soy and soy-based foods have been gaining in popularity as a functional food for specific health conditions. Increased media coverage touting the health benefits of soy has generated a rise in consumer awareness. Two soy-blueberry burgers were prepared using 10 and 15% blueberry puree. A soy burger ...


Gelation Of Previously Cooked Jonah Crab (Cancer Borealis) Minced Meat In New Food Product Development, Shari R. Baxter May 2007

Gelation Of Previously Cooked Jonah Crab (Cancer Borealis) Minced Meat In New Food Product Development, Shari R. Baxter

Electronic Theses and Dissertations

Gelation of meat products plays an important role in utilization of by-products. Low-value muscle tissue that may go to waste can be reformed into new products that consumers find acceptable and want to purchase. In the crab industry, the need for byproduct utilization is great. Crab processing typically involves cooking whole crabs and picking the claw meat. A lower grade minced meat can then be extracted mechanically from the walking legs and carapace of the crab. Traditional protein chemistry indicates that only raw muscle proteins can form gels. However, by using a modified surimi processing technique, previously cooked Jonah crab ...


Tourism Stakeholders Envision A Sustainable Path: Strengthening Maine's No. 1 Industry Through The Blaine House Conference Recommendations, Elizabeth Munding Jan 2006

Tourism Stakeholders Envision A Sustainable Path: Strengthening Maine's No. 1 Industry Through The Blaine House Conference Recommendations, Elizabeth Munding

Electronic Theses and Dissertations

Tourism, as Maine’s No. 1 industry, draws approximately 44 million visitors annually who spend $6 billion and contribute $340 million in sales tax. Despite these figures, annual statistics show zero growth or, often, loss, with the exception of the outdoor recreation sector. The tourism industry, made of government bodies, recreation associations and individual businesses, depends on the health of the natural resources and the compliance of related players, such as landowners. Discontent exists with the state and the industry’s leadership. The quandary comes in determining which actions to take to improve the state’s existing nature-based tourism into ...


Dietary Patterns Of Mediterranean Adolescents, Sandra Ellan Brussee Aug 2005

Dietary Patterns Of Mediterranean Adolescents, Sandra Ellan Brussee

Electronic Theses and Dissertations

The Mediterranean Diet (MD) is renowned for its health benefits. However, adherence appears to be lessening in the Mediterranean region as rates of overweight, obesity, and chronic disease are increasing. The adoption of a "western diet" (high amounts of meats, refined grains, snacks, and fast-food products) has been termed the "Nutrition Transition". Adolescents appear to be the most affected; therefore their diets and eating patterns were examined in this study. The objectives were to study food group-based consumption of adolescents, compare average servings with recommendations from the USDA Food Guide Pyramid (FGP) and the MD Pyramid, identify and compare eating ...


The Effect Of Dietary Manganese On Arterial Functional Properties, Anastasia Z. Kalea Aug 2005

The Effect Of Dietary Manganese On Arterial Functional Properties, Anastasia Z. Kalea

Electronic Theses and Dissertations

Dietary manganese affects the structure and integrity of blood vessels, as well as vessel predisposition to endothelial dysfunction and cardiovascular disease. In this thesis, we studied the role of manganese on the functional properties of rat aorta as defined by the endothelial and vascular smooth muscle cell pathways for adrenergic-mediated vasoconstriction and cholinergic-mediated vasodilation. Weanling Sprague-Dawley rats were fed a manganese deficient (MnD), adequate (MnA-control group) or supplemented (MnS) diet (<1, 10-15 and 45-50ppm Mn respectively). After 14 weeks on the diet the aorta was excised and four aortic rings of three mm length were prepared from each animal. Alterations in vasoconstriction among diet groups were detected by dose-response curves to the ^-adrenergic agonist LPhenylephrine in endothelium-intact and endothelium-disrupted rings. Alterations in endothelium-dependent vasodilation among diet groups were determined by doseresponse curves to Acetylcholine. We studied the mechanism by which dietary manganese affects two different endothelium-dependent vasodilation pathways: the Larginine/ nitric oxide (NO) and the cyclooxygenase (COX) pathways. Inhibition of the enzymes for NO synthesis (NOS) with L-NMMA, and of prostanoids (COX I and II) with Mefenamic acid, determination of NOS expression, and in vitro addition of L-Arginine (substrate for NO formation) to vessel rings revealed the effect of manganese on the regulation of endothelium-mediated vasodilation and vasoconstriction. Dose-response curves to sodium nitroprusside provided data for the dietary effect on endotheliumindependent vasodilation. Supplementary dietary manganese increased adrenoreceptor-mediated vascular smooth muscle contraction, which was significantly reduced in the presence of functional endothelium. Absence of dietary manganese increased endothelial cell sensitivity to the (Xi-adrenergic vasoconstrictor agent. Manganese had a small effect on the cGMP-pathway for dilation of vascular smooth muscle but affected vasodilation primarily through an endothelium-mediated pathway, probably by preserving NO bioavailability. Inhibition of vasodilation in Mn deficiency appears to occur through an endothelium-derived vasoconstrictor, possibly thromboxane with a concomitant decrease in the synthesis of endothelium-mediated vasodilator prostanoids. Our results demonstrate that dietary manganese influences the contractile machinery of vascular smooth muscle cells and regulates the bioactivity of endothelium-mediated vasodilators to affect agonist-induced signaling pathways that participate in the regulation of vasomotor tone. This suggests possibilities for dietary intervention in blood pressure regulation.


The Effect Of Whole Wild Blueberries On Endothelial Function Of The Sprague-Dawley Rat As Related To Cardiovascular Disease, Cynthia Ann Norton Dec 2003

The Effect Of Whole Wild Blueberries On Endothelial Function Of The Sprague-Dawley Rat As Related To Cardiovascular Disease, Cynthia Ann Norton

Electronic Theses and Dissertations

Weanling male Sprague-Dawley rats were randomly fed three different diets (n=8 per group), a control diet (AIN '93) (C), a blueberry diet (B) for 13 weeks and a reverse diet (R)(C for 13 weeks, switched to B for 8 weeks). Aortae were excised, rings were prepared, and two intact and two denuded rings were immersed in tissue baths containing physiological salt solution (PSS) at 37OC, aerated with 95% 0 2 and 5% CO2 (pH 7.4). Following equilibration and pre-conditioning under 1 Sgm preload, cumulative dose response curves were generated with six doses of the a-1 adrenergic receptor ...