Showing papers by "University of Guelph published in 1987"

Anthocyanins as food colorants —a review

Abstract: A number of factors affecting anthocyanin stability and color are discussed in this review. The anthocyanins are probably the most spectacular of plant pigments since they are responsible for most of the red, purple and blue pigmentation of flowers, fruits and vegetables. However, because of their highly reactive nature, anthocyanins readily degrade, or react with other constituents in the media, to form colorless or brown colored compounds. The presence of an ox-onium ion adjacent to carbon 2 makes the anthocyanins particularly susceptible to nucleophilic attack by such compounds as sulfur dioxide, ascorbic acid, hydrogen peroxide and even water. Loss of anthocyanin pigmentation also occurs in the presence of oxygen and various enzymes, and as a result of high temperature processing. A certain degree of pigment stabilization may be conferred by acylation with various organic acids, copigmentation, self-association and/or metal chelation. In addition, pH has a marked effect on anthocyanin stability, and on the color of media containing these pigments. A number of anthocyanin-rich sources have been investigated for their potential as commercial pigment extracts. Although their application is primarily limited to acidic media, continued research on the chemistry of anthocyanins may lead to application and stabilization of these pigments in a wider variety of food products.

Introduction to noncovariant gauges

Abstract: The most important single attribute of noncovariant gauges is their ghost-free nature. Although noncovariant gauges have been an integral part of quantum field theory for many decades, their effectiveness in the quantization of non-Abelian theories and their broad range of applicability have only recently been appreciated by theorists at large. The purpose of this review is to explain and illustrate the essential characteristics of some typical noncovariant gauges, such as the axial gauge, the planar gauge, the light-cone gauge, and the temporal gauge. The author's aim is to acquaint the reader not only with the basic properties of these ghost-free gauges, but also with their deficiencies and advantages over covariant gauges, their computational idiosyncrasies, and their dominant areas of application.

Family and friends as social environments and their relationship to young adolescents' use of alcohol, tobacco, and marijuana.

Abstract: This study examines the role of family and friends in accounting for alcohol, tobacco, and marijuana use among young adolescents. The sample included 1,008 males and 1,040 females with a mean age of 14.5 years. Lack of parental affection, concern, involvement, and modeling appeared to be centralfactors in the family's influence, which accounted for up to 22% of the variance in drug use. Friends' delinquency and use of drugs largely determined the influence of friendship, which accounted for up to 40% of adolescent drug use. Comparisons are made between characteristics of family and friends.

Mercury levels in Bonaparte's gulls (Larus Philadelphia) during autumn molt in the Quoddy region, New Brunswick, Canada

Abstract: No significant between sex differences were detected in Hg concentrations in primary feathers, pectoral muscle, brain, liver, and kidney tissues of fall migrating juvenile and second-year Bonaparte's gulls (Larus Philadelphia) collected in the Quoddy region. Adults showed sexual differences only in the first 5 primary feathers, and in muscle, kidney and brain. Differences in Hg concentrations among age groups were reflected in the primary feathers and body tissues, but as the molt progressed, Hg concentrations decreased as they converged toward a minimum asymptotic Hg level for each tissue. This suggests that the body burden of Hg was reduced through its redistribution from the body tissues into the growing feathers. Mercury concentrations in premolt head feathers (pre-egg-laying) did not vary significantly between adult females and males, whereas Hg concentrations in postmolt feathers (post-egg-laying) were significantly lower in females, suggesting that egg-laying was also a route for Hg elimination. After the completion of the molt, the new feathers contained most of the body burden of Hg (93.0% in adults).

Synthesizing Statistical Knowledge from Incomplete Mixed-Mode Data

Abstract: The difficulties in analyzing and clustering (synthesizing) multivariate data of the mixed type (discrete and continuous) are largely due to: 1) nonuniform scaling in different coordinates, 2) the lack of order in nominal data, and 3) the lack of a suitable similarity measure. This paper presents a new approach which bypasses these difficulties and can acquire statistical knowledge from incomplete mixed-mode data. The proposed method adopts an event-covering approach which covers a subset of statistically relevant outcomes in the outcome space of variable-pairs. And once the covered event patterns are acquired, subsequent analysis tasks such as probabilistic inference, cluster analysis, and detection of event patterns for each cluster based on the incomplete probability scheme can be performed. There are four phases in our method: 1) the discretization of the continuous components based on a maximum entropy criterion so that the data can be treated as n-tuples of discrete-valued features; 2) the estimation of the missing values using our newly developed inference procedure; 3) the initial formation of clusters by analyzing the nearest-neighbor distance on subsets of selected samples; and 4) the reclassification of the n-tuples into more reliable clusters based on the detected interdependence relationships. For performance evaluation, experiments have been conducted using both simulated and real life data.

Fat crystal networks: structure and rheological properties

Abstract: The solid character of plastic fats is the result of the presence of a certain percentage of crystallized fat Although methods are now available to measure solid/liquid ratios without difficulty, there is no conclusive theory which will relate crystal size and shape, solid fat content and rheological properties It is generally assumed that plastic fats contain a three-dimensional network of fat crystals, held together by primary (nonreversible) and secondary (reversible) bonds This paper highlights the hypotheses that have been put forward concerning the forces existing between fat crystals, the rheological properties of plastic fats, and recent information on crystal network structure

Comparison of total mercury levels in relation to diet and molt for nine species of marine birds

Abstract: Total mercury (Hg) concentrations were analyzed for tissues of nine species of marine birds from the Quoddy region, New Brunswick, Canada, including cormorants (Phalacrocorax auritus), eiders (Somateria mollissima), guillemots (Cepphus grylle), phalaropes (Phalaropus lobatus), gulls (Larus argentatus, L. Philadelphia), terns (Sterna hirundo, S. paradisaea) and kittiwakes (Rissa tridactyla). There was a progressive decrease in Hg concentration from the innermost to the outermost primary feather in Bonaparte's gulls, herring gulls, black-legged kittiwakes and Arctic terns. Primaries of common terns and black guillemots showed no significant trend. Cormorants, guillemots and eiders, which feed on benthic organisms, and common terns, which feed predominantly on fish, had the highest tissue Hg levels, whereas birds such as kittiwakes and phalaropes, which consume mainly pelagic invertebrates, had the lowest Hg levels.

Second language attrition: The role of motivation and use.

Abstract: This study investigated the nature of second language (French) skills lost by grade 12 students over the course of the summer vacation, and the role played by attitudes and motivation in promoting language achievement and language maintenance. The results demonstrated that students rated many of their skills somewhat weaker after the summer vacation, but these effects were more general for items dealing with understanding skills than for speaking skills, and somewhat intermediate for reading and writing skills. Comparisons on objective assessments appeared to indicate improvement over the summer months on some skills, except for grammatical accuracy, that decreased, but these were interpreted as quite probably reflecting measurement artifacts. Although the attitude and motivation measures correlated quite meaningfully with the various measures of French proficiency, they did not correlate with loss of skill as indexed by simple change scores. A causal modelling analysis indicated nonetheless that attitude...

Synthesis of the infectious pancreatic necrosis virus polyprotein, detection of a virus-encoded protease, and fine structure mapping of genome segment A coding regions.

Abstract: Full-length and truncated genome segment A-specific infectious pancreatic necrosis virus cDNA was subcloned into plasmid transcription vectors, and runoff transcripts were produced in vitro. These transcripts were translated in cell-free rabbit reticulocyte lysates and the translation products were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Virus-specific polypeptides were gel purified and mapped by partial proteolysis with N-chlorosuccinimide and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Peptide profiles were compared with those of the corresponding polypeptides purified from infectious pancreatic necrosis virus-infected cells or prepared by in vitro translation of denatured genomic RNA. The cDNA directed the synthesis of authentic pVP2, VP3, and NS polypeptides as well as a number of previously undescribed polypeptides. A 101,000-molecular-weight polypeptide was isolated and shown to be the unprocessed infectious pancreatic necrosis virus polyprotein. The NS polypeptide appears to be a virus-encoded protease responsible for the cleavage of pVP2 from the polyprotein. The carboxy terminus of NS was mapped to within three or four amino acids on the polyprotein. The most likely internal translation start sites responsible for NS and VP3 production in vitro were also mapped.

Production of 1,3-Propanediol from Glycerol by Clostridium acetobutylicum and Other Clostridium Species.

Abstract: Glycerol was fermented with the production of 1,3-propanediol as the major fermentation product by four strains of Clostridium acetobutylicum, six of C. butylicum, two of C. beijerinckii, one of C. kainantoi, and three of C. butyricum. 1,3-Propanediol was identified by its retention times in gas chromatography and high-pressure liquid chromatography and by its mass spectrum. During growth of C. butylicum B593 in a chemostat culture at pH 6.5, 61% of the glycerol fermented was converted to 1,3-propanediol. When the pH was decreased to 4.9, growth and 1,3-propanediol production were substantially reduced.

Resolutions of control episodes between well and affectively ill mothers and their young children.

Abstract: Control interactions between 87 well and affectively ill mothers and their 15- to 51-month-old children were studied. Spontaneously occurring control interventions (conceptualized as episodes of interaction between mother and child) were coded from 90 minutes of videotaped interactions in a naturalistic laboratory apartment setting. The results suggest developmental changes in mother-child interaction in the 2nd to 4th years of life: the increase of the rate of immediate maternal success (p < .05) and compromise (p < .05), on the decrease in maternal use of power (ultimate sucess by enforcement, p < .01). Well mothers achieved compromise with their children, particularly daughters, more often than did affectively ill mothers (p < .05). Affectively ill mothers more often than well mothers avoided confrontation with their children (p < .05). The impairments in control interventions of affectively ill mothers were exacerbated by the severity of the disorder.

Dynamic mechanical analysis studies of the interphase

Abstract: The dynamic mechanical properties of unidirectional glass-fiber-reinforced polyester measured along the fiber direction were recently investigated In the same polyester, the type of organosilane coated on the glass fiber, the amount of organosilane, the fiber volume fraction, and the fiber diameter affect the value of the loss tangent, tan δ, at the glass-transition temperature of the glass-fiber-reinforced polyester The interfacial shear strength and the tan δ at the glass-transition temperature of the glass-fiber-reinforced polyester show good correlation suggesting that the latter can be used to characterize the quality of the interphase Factors affecting the glass-transition temperature and the application of Zorowski and Murayama's equation in the characterization of the interfacial adhesion are also discussed

Extensive homology between the leukotoxin of Pasteurella haemolytica A1 and the alpha-hemolysin of Escherichia coli.

Abstract: The 19.8- and 101.9-kilodalton leukotoxin proteins of Pasteurella haemolytica (LKTC and LKTA, respectively) share extensive homology with the HLYC and HLYA alpha-hemolysin proteins of Escherichia coli. The leukotoxin LKTA protein cross-reacts with hemolysin-specific antisera in Western blot (immunoblot) analysis, indicating that it shares epitopes with the alpha-hemolysin HLYA protein. Both LKTA and HLYA contain a conserved hydrophobic region, as well as a set of tandemly repeated domains. These features have been implicated in the lytic function of the alpha-hemolysin.

Production of cole crops which exhibit triazine tolerance

Abstract: Improved plants of Brassica oleracea and seeds capable of forming the same are provided. Such plants are fully male and female fertile and possess the usual complement of 18 chromosomes. However, unlike previously available cole crops, these plants exhibit cytoplasmic triazine tolerance when atrazine is applied as a foliar spray at a rate of 1.5 kilograms per hectare. For the first time a triazine herbicide can effectively be used to destroy unwanted broadleaf weeds which have a propensity to grow in the same planting area with the cole crop. Accordingly, an improved process for producing a cole crop is provided through the application of triazine to the planting area.

Inhibition of hepatocarcinogenic responses to 1,2-dimethylhydrazine by diallyl sulfide, a component of garlic oil

Abstract: The mechanisms by which diallyl sulfide (DAS), a component of garlic oil, inhibits hepatocarcinogenicity of 1,2-dimethylhydrazine (DMH) were examined in male Fischer 344 rats. Rats were subjected to partial hepatectomy to stimulate hepatocellular proliferation required for initiation by DMH (50-200 mg/kg i.p.) given 12 h later. Initiation was assessed by the numbers of foci and nodules of hepatocytes that were positive for gamma-glutamyl transpeptidase (gamma-GT) or glutathione-S-transferase-P (GST-P) after 6 weeks promotion by orotic acid (1% in semi-purified diet). DAS at doses above 50 mg/kg (by gavage) administered 1 h before DMH (50 mg/kg) partially reduced the numbers of gamma-GT and GST-P-positive foci. By comparison, all doses of DAS (25-100 mg/kg) completely prevented liver necrosis by DMH (200 mg/kg). DAS substantially reduced macromolecular binding of [14C]DMH in cultured liver cells, but had no effect on their levels of glutathione-S-transferase, glutathione reductase or glutathione peroxidase at 18 h. These findings suggest that low dosages of DAS which reduce DMH binding appear more likely to inhibit hepatocarcinogenicity by reducing the promoting influences of post-necrotic regeneration than by preventing initiation.

Ingestion of Fish Oil or a Derived n-3 Fatty Acid Concentrate Containing Eicosapentaenoic Acid (EPA) Affects Fatty Acid Compositions of Individual Phospholipids of Rat Brain, Sciatic Nerve and Retina

Abstract: The effect of feeding redfish (Sebastes marinus or mantella) oil or a derived n-3 fatty acid concentrate containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the fatty acid compositions of individual phospholipids in selected neural tissues was studied in growing male rats. Control animals were given sunflower oil in the diet for the 5-wk feeding trial. Lipid analyses revealed that EPA (20:5n-3) became significantly enriched in all phospholipid fractions (phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol) in the tissues studied (brain, retina and sciatic nerve) in the two n-3 fatty acid dietary groups relative to controls. Corresponding changes were also found in the 22:5n-3 contents of these tissues, whereas little or no significant elevation in DHA (22:6n-3) was found. In contrast, the percentages by weight of the n-6 fatty acids including 18:2n-6, 20:4n-6 (arachidonic acid, AA), 22:4n-6 and 22:5n-6 were generally lower in the various phospholipids/tissues of the animals given fish oil or the n-3 fatty acid concentrate; the levels of 22:5n-6 and 22:4n-6 were markedly affected in this regard. These results indicate that dietary n-3 fatty acids (as EPA plus DHA) can greatly affect the fatty acid compositions of the various membrane phospholipids in nervous tissues within a relatively short time. These biochemical alterations may be important for functional changes including altered membrane fluidity, cellular responses, ion transport and the biosyntheses of AA- and EPA-derived prostaglandins and leukotrienes.

Structural States of Mg-Cordierite I: Order Parameters from Synchrotron X-Ray and NMR Data

Abstract: The hexagonal to orthorhombic phase transition in synthetic Mg-cordierite has been studied by (i) measuring the spontaneous strain associated with the transition using Synchrotron X-ray powder diffraction and (ii) measuring the degree of Al, Si order in terms of the number of Al-O-Al bonds per formula unit using solid state NMR spectroscopy. This defines the two order parametersQ andQ od respectively, and their relationship as a function of annealing temperature and time is used to define the structural states of cordierite during the ordering sequence. The formation of modulated hexagonal cordierite within which a high degree of Al, Si order can be attained, results in a strongly non-linear relationship betweenQ andQ od .The transition from modulated to orthorhombic cordierite is strongly first-order under all temperature conditions studied and involves a large step inQ, whileQ od changes continuously throughout the ordering sequence with no marked discontinuity at the phase transition. The lattice distortion, traditionally defined in cordierite by the Δ index provides no full information on the degree of Al, Si order in anhydrous Mg-cordierite, and both order parameters must be used to define its structural state. Transmission electron microscopy has been used to study the mechanism of the transformation from hexagonal to modulated to orthorhombic cordierite.

Calcium logistics in the laying hen.

Abstract: The hourly changes in the Ca2+ content of various physiological compartments in relation to shell formation has been calculated for the domestic hen throughout a 4-d ovulatory sequence. These calculations consider the circadian rhythm in Ca2+ intake when the hen is fed a complete feed or a diet containing oyster shell, the effect of the stage of the ovulatory sequence and the stage of shell formation. The calculations indicate that medullary bone accrues Ca2+ during the day and that Ca2+ is drawn from the bone reserve during the scotophase if shell calcification is active. When fed Ca2+ as an identifiable feedstuff, the hen will ingest large amounts of Ca2+ at the end of the photophase. Some of this Ca2+ is temporarily stored in medullary bone and the remainder is metered into the lower digestive tract throughout the early part of the scotophase. It is suggested that the preovulatory surge of estrogens sensitizes medullary bone to the osteoclastic effect of parathyroid hormone, the production of which is stimulated by a decline in the total and ionized concentrations of Ca2+ during shell formation.