Showing papers by "University of Guelph published in 1985"

Hybridization using cytoplasmic male sterility, cytoplasmic herbicide tolerance, and herbicide tolerance from nuclear genes

Abstract: The process of the present invention provides a convenient route for producing a predetermined hybrid variety of a crop which is capable of undergoing both self-pollination and cross-pollination Cytoplasmic male sterile plants which also exhibit cytoplasmic herbicide tolerance (ie, to a Type A herbicide) and tolerance to a different herbicide attributable solely to nuclear genes (ie, to a Type B herbicide) are the key plants for use in the present process The maintainer and restorer plants exhibit tolerance to different herbicides (ie, to either a Type A herbicide or a Type B herbicide) The economical bulk planting of the parent plants is made possible during each step of the process For instance, cytoplasmic male sterile plants, plants resulting from the self-pollination of a maintainer, and restorer plants can be grown in a substantially random population, with the self-pollinated maintainer plants being destroyed by an appropriate herbicide prior to pollination, and the self-pollinated restorer plants being destroyed by an appropriate herbicide immediately following pollination or in the subsequent generation The process of the present invention is applicable to grain crops, forage crops, seed-propagated fruits, seed-propagated ornamentals, and industrial species In a particularly preferred embodiment a predetermined variety of Brassica napus (ie, rape or improved forms thereof known as canola) is formed which is the product of cross-pollination

Multiple Discrepancies Theory (MDT)

Abstract: A fairly thorough account of multiple discrepancies theory (MDT) is presented, with a review of its historical antecedents and an examination of its strength in accounting for the happiness (H) and satisfaction (S) of nearly 700 university undergraduates. Basically, MDT asserts that H and S are functions of perceived gaps between what one has and wants, relevant others have, the best one has had in the past, expected to have 3 years ago, expects to have after 5 years, deserves and needs. MDT explained 49% of the variance in H, 53% in global S and 50% or more in 7 out of 12 domain S scores. The domains studied were health, finances, family, job, friendships, housing, area, recreation, religion, self-esteem, transportation and education.

Hybridization using cytoplasmic male sterility and herbicide tolerance from nuclear genes

Abstract: The process of the present invention provides a convenient route for producing a predetermined hybrid variety of a crop which is capable of undergoing both self-pollination and cross-pollination. Cytoplasmic male sterile plants which also exhibit herbicide tolerance attributable solely to nuclear genes are the key plants for use in the present process. Economical bulk planting of the key plants with either maintainer or restorer plants is made possible. Following cross-pollination from a pollen source which lacks the herbicide tolerance unneeded plants effectively are eliminated by use of a herbicide. For instance, unwanted plants may be effectively eliminated immediately after pollination or prior to pollination in the succeeding generation (provided the requisite genes for herbicide tolerance are present therein) to make possible the existence in an unharmed state of a substantially homogeneous stand of the desired plants. In a preferred embodiment cytoplasmic male sterile plants, plants resulting from the self-pollination of a maintainer, and restorer plants are planted in a substantially random population prior to the application of two different herbicides (as defined) at the appropriate times. The process of the present invention is applicable to grain crops, forage crops, seed-propagated fruits, seed-propagated ornamentals, and industrial species. In a particularly preferred embodiment a predetermined variety of Brassica napus (i.e., rape or improved forms thereof known as canola) is formed which is the product of cross-pollination.

Evidence of heavy-neutrino emission in beta decay.

Abstract: The observation of a distortion of the $\ensuremath{\beta}$ spectrum of tritium is reported. This distortion is consistent with the emission of a neutrino of mass about 17.1 keV and a mixing probability of 3%.

Flower petal microtexture is a tactile cue for bees

Abstract: Honeybees are shown to be able to detect, learn, and discriminate between microsculptured epidermes of flower petals The sensilla trichodea at the tips of the bees' antennae are in the same size range as the microsculptural features of the petals (ca 10 μm), which presumably deflect these mechanoreceptive sensilla in characteristic ways Honeybees were trained to associate reward with one floral texture and to choose that over another Further, the bees also recognized differences in textures at different ends of petals of the same species The phenomenon is significant in that it suggests another way in which insect pollinators can discriminate between the flowers of different plant species and so act as species isolators Also, the microsculptural patterns differ from one end of a petal to the other and, therefore, can be used as nectar-guides by foraging bees This study presents a previously unreported conditioned response to texture by insects and shows the functional significance of a floral character used in plant taxonomy

A family-of-origin scale†

Abstract: While family-of-origin interventions are widely used, the theoretical assumptions upon which these techniques are based are largely without empirical validation. This paper reports on the development of a family-of-origin scale that may be used in such research as well as employed as an adjunct to therapy. The resultant scale attempts to measure self-perceived levels of health in one's family of origin. Presented are data pertaining to the scale's validity, reliability, and normative sample.

Stochastic models of failure in random environments

Abstract: Stochastic models of failure modes of frequent occurrence in the engineering sciences are considered The failure-producing stress environment is modelled as a stationary stochastic process Using theoretical properties of the sample paths of these processes, failure-time distributions which belong to the Birnbaum-Saunders family are obtained Several examples of particular engineering relevance are treated Grǎce aux processus stochastiques, il est possible de representer de maniere assez juste de nombreux types de defaillances ďorigine repandue en ingenierie Un processus stochastique en regime permanent peut notamment servir de modele pour certaines causes exogenes de defaillance En faisant appel aux proprietes des chemins echantillonnaux de tels processus, il est possible de calculer les distributions des temps de bris On constate que celles-ci appartiennent a la famille de lois dite de Birnbaum-Saunders On presente aussi de nombreux exemples ďinterět pratique

Social Networks and Social Support: An Overview of Research, Practice, and Policy Implications

Abstract: Following a brief overview of the stressful life events-illness model and its implications for intervention, this article highlights the role of social support as a resource for resisting stress- induced illness and disability. It identifies three different connotative meanings that have been assigned to the social support construct, and describes their empirical operationalizations in several recent studies. Specifically, the social integration/participation formulation, the social network approach, and the social intimacy measurement strategy are described and contrasted. Within the latter approach, one study that illuminated types of informal helping behaviors is discussed in greater detail. A review of possible mechanisms whereby social support accom plishes its health-protective impact is also offered, and two types of planned interventions involving the mobilization or optimization of social support are spotlighted. The article concludes with ideas about ways that professionals can safeguard the nat...

Digestion and absorption of carbohydrates in fowl and events through perinatal development.

Abstract: Starch is the main carbohydrate in the food of poultry. Starch granules are digested by pancreatic alpha-amylase in the small intestine. Intestinal villi have enterocytes that project microvilli with a fibrous glycocalyx from the surface. These fine structures are envisaged to entrap water that is mixed with mucin from nearby goblet cells to form the "unstirred water layer." Maltose, maltotriose and alpha-limit dextrins must diffuse across this first barrier to absorption to be hydrolyzed by maltase and sucrase-isomaltase immobilized at the membrane; however, the resultant glucose, once formed, accrues at the surface to provide a concentration advantage. Fowl adjust to changes in dietary starch by altering the amount of amylase released, intestinal surface area and enterocyte carbohydrase concentration. Enterocytes arising during embryonic development have no carbohydrases and are not involved with glucose absorption, but they appear to be specialized for maternal immunoglobin transfer in ovo. Embryonic villi are stimulated by transfer activity, and their growth depends on enterocytes arising from the crypt. Mature crypt cells are capable of digestion-absorptive activities and dominate the villus shortly after the chick hatches when yolk sac reserves are depleted.

A review of textural defects in cooked reconstituted legumes —the influence of structure and composition

Abstract: Legumes provide an important part of the world's protein requirements, as well as other nutrients, but they are underutilized as food. A major factor limiting expanded consumption is storage induced textural defects that prolong cooking time and demand correspondingly higher energy requirements for preparation. These defects, including the hard-to-cook phenomenon and hardshell, are initiated by structural and compositional factors but can be at least partially controlled by storage and processing conditions. Structural components implicated include seed coat, cell walls, middle lamella, starch granules and membranes while, compositionally, proteins, carbohydrates, phytate, polyphenols and lignin may also be important. Methods of texture measurement of legumes, including mechanical, physical and sensory properties are reviewed. The most commonly held hypothesis for the mechanism of the hard-to-cook defect states that beans fail to soften after exposure to high temperature and humidity storage because the increased water activity potentiates phytase which hydrolyzes phytate, rendering it no longer capable of chelating the Ca++ and Mg++ ions of the middle lamella and, hence, undissoluble. More recent evidence, however, provides potential roles for lignification, starch gelatinization and perhaps other mechanisms depending upon conditions. The possibility of a nonenzymatic as well as an enzymatic route is raised and thoughts presented on a course of action for future research.

Characteristics and composition of melon and grape seed oils and cakes

Abstract: Watermelon (Citrullus vulgaris) and grape (Vitis vinifera) seeds were investigated for their nutritional quality and oil characteristics. The yields of seeds on an as is basis (edible portion) were 1.6 and 1.8% for grape and melon, respectively. The melonseed on a dry weight basis consisted of 53.6% testa and 46.4% kernel. The crude protein, fat and fiber content were 16.4, 23.1 and 47.7% for melon and 8.2, 14.0 and 38.6% for grape (dry weight basis). Both seeds were found to contain significant levels of Ca, Mg, P and K. The fatty acid profiles showed an unsaturated fatty acid content of 76.1% for melonseed oil and 88.6% for grapeseed oil. The predominant fatty acid in both seeds was linoleic acid. The iodine value, saponification number and acid value were 116, 248 and 0.97 for melonseed oil and 132, 194 and 1.59 for grapeseed oil. The amino acid profiles of both seed cake proteins were determined and compared with hen’s egg protein.

Social Support and the Study of Personal Relationships

Abstract: The study of social support as a resource for resisting stress has been pursued independently of its role in the initiation and maintenance of personal relationships. Moreover, the tendency to define and measure support, like loneliness, in psychological rather than transactional terms will further limit knowledge about the conduct of close relationships. While psychological or perceived support is strongly coloured by personality variables and is not an accurate predictor of the support that actually materializes, it does play a critical role in the cognitive appraisal process. In contrast, experienced or received support figures centrally in the actual coping process. In addition there are covert, unintentional, and indirect forms of support that have been overlooked due to researchers' exclusive focus on the prosocial potential and behaviours of the social network. The article concludes by spotlighting two topics warranting integrative research in the fields of personal relationships and social support.

Constraints in the performance of bimanual tasks and their expression in unskilled and skilled subjects

Abstract: Unskilled and skilled subjects were asked to perform a variety of bimanual tapping tasks. Three major effects were seen. First, right-handers performed dual tasks better when the preferred hand took the “figure” and when the nonpreferred hand took the “ground” of the dual movement. This effect was not seen in left-handers. Second, subjects performed a simple slow/fast dual task better when they commenced the task with the fast rather than with the slow hand. This effect was seen in right- and lefthanders. Third, both unskilled and skilled subjects showed marked interdependence of movements such that performance of one hand was a function of movements in the other hand. The results are in agreement with a model that postulates the presence of a superordinate control mechanism that initiates action in subordinate control mechanisms, which in turn set the movement trajectories in the two hands. The results also show that attention is an important factor in the interaction between these two levels of...

Polychlorinated biphenyls: Correlation between in vivo and in vitro quantitative structure-activity relationships (QSARs)

Abstract: The in vivo quantitative structure‐activity relationships (QSARs) for several polychlor‐inated biphenyls (PCBs) were determined in the immature male Wistar rat. The ED25 and ED50 values for hepatic microsomal aryl hydrocarbon hydroxylase (AHH) and ethoxyresorufin O‐deethylase (EROD) induction as well as for body weight loss and for thymic atrophy were determined for nine PCB congeners and 4'‐bromo‐2,3,4,5‐tetrachlorobiphenyl. The most active compounds were the coplanar PCB congeners, 3,3’,4,4’,5‐penta‐ and 3,3’,4,4’,5,5'‐hexachlorobiphenyl; for example, their ED50 values for body weight loss were 3.25 and 15.1 μmol/kg, respectively. The in vivo toxicity of the coplanar PCB, 3,3’,4,4'‐tetrachlorobiphenyl, was significantly lower (ED50 for body weight loss = 730 μmol/kg) than the values observed for the more highly chlorinated homologs, and this was consistent with the more rapid metabolism of the lower chlorinated congener. The dose‐response biologic and toxic effects of several mono‐ortho‐chloro‐substitut...

27Al and29Si magic angle spinning nuclear magnetic resonance spectroscopy of Al-substituted tobermorites

Abstract: Solid-state27Al and29Si NMR spectroscopy with magic angle spinning (MAS) of samples was used to study several 1.13 nm tobermorites, most of which were deliberately substituted with aluminium.27Al MASNMR clearly showed that aluminium is tetrahedrally co-ordinated in tobermorite structures. In addition two different aluminium environments resonating at ∼ 57 and 64 ppm from [Al(H2O)6]3+ were detected.29Si MASNMR of pure, anomalous tobermorites showed resonances at −85.7 and −95.7 ppm from tetramethylsilane representing chain middle groups (Q2) and branching sites (Q3), respectively. Anomalous Al-substituted tobermorites, on the other hand, showed two to four resonances representing different silicon environments. One Al-substituted tobermorite showed two resonances at −84.6 and −91.5 ppm which were assigned to Q2(0 Al) and Q3 (1 Al), respectively. In the above tobermorite aluminium appeared to have substituted into branching sites only. Two other Al-substituted tobermorites, however, showed four distinct resonances at ∼ −82.0, −85.2, −92.0 and −96.0 and these were assigned to Q2 (1 Al), Q2 (0 Al), Q3 (1 Al) and Q3 (0 Al), respectively. Thus these two tobermorites showed substitution of aluminium in the chain middle groups as well as branching sites. Another Al-substituted tobermorite which showed a normal thermal behaviour exhibited, as expected, only Q2(0 Al) and Q2 (1 Al) sites resonating at −84.7 and ∼ −80.2 ppm, respectively. No Q3 sites were detected because few or no branching sites are present in this normal tobermorite. The results reported here clearly demonstrate the usefulness of solid-state27Al and29Si MASNMR spectroscopy for the investigation of short-range order in alumino-silicate materials.

Effect of rearing density on thyroid and interrenal gland activity and plasma and hepatic metabolite levels in rainbow trout, Salmo gairdneri Richardson

Abstract: There were significant inverse correlations between rearing density of rainbow trout, Salmo gairdneri Richardson, and final body weight, plasma L-thyroxine (T4), truodo-L-tryronine (T3), cortisol and protein concentrations, plasma T4/T3 ratios and thyroid epithelial cell height. In addition, hepatosomatic indices and plasma free fatty acid concentrations were higher in fish reared at low (134 g 1−1) density compared with groups reared at medium (210g1−1) or high density (299g 1−1), and the post-feeding (3.5-4h) elevation in plasma glucose and triglyceride levels evident in trout maintained at low rearing density was not found in those fish reared at higher densities. There were no significant effects of rearing density on hematocrit, carcass composition, hepatic glycogen and lipid levels and interregnal nucleus size.

Cellulolytic Activity of Clostridium acetobutylicum.

Abstract: Clostridium acetobutylicum NRRL B527 and ATCC 824 exhibited extracellular and cell-bound endoglucanase and cellobiase activities during growth in a chemically defined medium with cellobiose as the sole source of carbohydrate. For both strains, the endoglucanase was found to be mainly extracellular (70 to 90%) during growth in continuous or batch cultures with the pH maintained at 5.2, whereas the cellobiase was mainly cell associated (60 to 90%). During continuous cultivation of strain B527 with cellobiose as the limiting nutrient, maximum production of the endoglucanase and cellobiase occurred at pH values of 5.2 and 4.8, respectively. In the carbon-limited continuous cultures, strain 824 produced similar levels of endoglucanase, cellobiosidase, and cellobiase activities regardless of the carbon source used. However, in ammonium- or phosphate-limited cultures, with an excess of glucose, only 1/10 of the endoglucanase was produced, and neither cellobiosidase nor cellobiase activities were detectable. A crude extracellular enzyme preparation from strain B527 hydrolyzed carboxymethylcellulose and phosphoric acid-swollen cellulose readily and microcrystalline cellulose (A vicel) to a lesser extent. Glucose accounted for more than 90% of the reducing sugar produced by the hydrolysis of acid-swollen cellulose and Avicel. Strain B527 did not grow in medium with acid-swollen cellulose as the sole source of carbohydrate, although it grew readily on the products obtained by hydrolyzing the cellulose in vitro with a preparation of extracellular cellulase derived from the same organism.

Na+ (Li+)-proline cotransport in Escherichia coli.

Abstract: Na+ and Li+ were found to stimulate the transport of L-proline by cells of Escherichia coli induced for proline utilization. The gene product of the put P gene is involved in the expression of this transport activity since the put P+ strains CSH 4 and WG 148 show activity and the put P- strain RM 2 fails to show this cation coupled transport. The addition of proline was found to stimulate the uptake of Li+ and of Na+. Attempts to demonstrate proline stimulated H+ uptake were unsuccessful. It is concluded that the proline carrier (coded by the put P gene) is responsible for Na+ (or Li+)-proline cotransport.

Xylanolytic Activity of Clostridium acetobutylicum.

Abstract: Of 20 strains of Clostridium spp. screened, 17 hydrolyzed larch wood xylan. Two strains of Clostridium acetobutylicum, NRRL B527 and ATCC 824, hydrolyzed xylan but failed to grow on solid media with larch xylan as the sole carbon source; however, strain ATCC 824 was subsequently found to grow on xylan under specified conditions in a chemostat. These two strains possessed cellulolytic activity and were therefore selected for further studies. In cellobiose-limited continuous cultures, strain NRRL B527 produced maximum xylanase activity at pH 5.2. Strain ATCC 824 produced higher xylanase, xylopyranosidase, and arabinofuranosidase activities in chemostat culture with xylose than with any other soluble carbon source as the limiting nutrient. The activities of these enzymes were markedly reduced when the cells were grown in the presence of excess glucose. The xylanase showed maximum activity at pH 5.8 to 6.0 and 65°C. The enzyme was stable on the alkaline side of pH 5.2 but was unstable below this pH value. The extracellular xylanolytic activity from strain ATCC 824 hydrolyzed 12% of the larch wood xylan during a 24-h incubation period, yielding xylose, xylobiose, and xylotriose as the major hydrolysis products. Strain ATCC 824, after being induced to grow in batch culture in xylan medium supplemented with a low concentration of xylose, failed to grow reproducibly in unsupplemented xylan medium. A mutant obtained by mutagenesis with ethyl methanesulfonate was able to grow reproducibly in batch culture on xylan. Both the parent strain and the mutant were able to grow with xylan as the sole source of carbohydrate in continuous culture with the pH maintained at either 5.2 or 6.0. Under these conditions, the cells utilized approximately 50% of the xylan. Images

Effect of cultural practices, soil phosphorus, potassium, and pH on the incidence of fusarium head blight and deoxynivalenol levels in wheat

Abstract: In a survey conducted in 1984 in Essex, Lambton, and Middlesex Counties of Ontario, Canada, greater incidences of head blight and greater concentrations of deoxynivalenol in grain were observed in fields of winter wheat planted after corn than in those planted after soybeans, barley, and mixed grains. Neither head blight nor deoxynivalenol level were correlated significantly with soil P, K, or pH. Head blight was reduced in wheat planted after corn where the residues from a preceding corn crop were plowed down or where seed was treated with Vitaflo 280. However, head blight and deoxynivalenol levels were not affected significantly by the level of N application, cultivar, other diseases or herbicides.

The effect of some carbon substrates on denitrification rates and carbon utilization in soil

Abstract: Soil was amended with a variety of carbon sources, including four soluble compounds (glucose, sucrose, glycerol and mannitol) and two plant residues (straw and alfalfa).. Potential denitrification rates, measured both as N2O accumulation and NO3− disappearance, were compared, and the predicted values of available C, measured as CO2 production and water-extractable C, were assessed.

Simulation of dehydration injury to membranes from soybean axes by free radicals.

Abstract: Smooth microsomal membranes were isolated from axes of soybean (Glycine max L. Merr.) seeds at the dehydration-tolerant (6 hours of imbibition) and dehydration-susceptible (36 hours of imbibition) stages of development and were exposed to free radicals in vitro using xanthine-xanthine oxidase as a free radical source. Wide angle x-ray diffraction studies indicated that the lipid phase transition temperature of the microsomal membranes from the dehydration-tolerant axes increased from 7 to 14°C after exposure to free radicals, whereas those from the dehydration-susceptible axes increased from 9 to 40°C by the same free radical dose. The increased phase transition temperature was associated with a decrease in the phospholipid:sterol ratio, and an increase in the free fatty acid:phospholipid ratio. There was no significant change in total fatty acid saturation, which indicated that free radical treatment induced deesterification of membrane phospholipid, and not a change in fatty acid saturation. Similar compositional and structural changes have been previously observed in dehydration-injured soybean axes suggesting that dehydration may induce free radical injury to cellular membranes. Further, these membranes differ in their susceptibility to free radical injury, presumably reflecting compositional differences in the membrane since these membranes were exposed to free radicals in the absence of cytosol.

Acclimation of rainbow trout, Salmo gairdneri Richardson, to zinc: kinetics and mechanism of enhanced tolerance induction

Abstract: Pre-exposure of rainbow trout to 0.31–0.53 of the lethal concentration of zinc increased their tolerance of the metal by a factor of 2.5. This acclimation was fully induced within 5 days, and completely lost within 7 days when fish were returned to zinc-free water. The changes in tolerance were closely paralleled by changes, in both liver and gill tissue, of heat-stable, sulfhydryl-rich protein (an estimate of levels of metal lothionein, MT). This strongly suggests that MT is involved in the induction of enhanced tolerance of zinc. Zinc residues in liver and gill tissue did not parallel the changes in MT levels and tolerance. Thus MT does not appear to bind and store excess zinc; however, it may increase the ability of acclimated fish to regulate the levels of zinc in their gills. This hypothesis is supported by the observation that the rate of accumulation of zinc in gill tissue was slower in acclimated fish than in control fish.

Is the United States Really Underinvesting in Agricultural Research

Abstract: That the level of public investment in U.S. agricultural research is too low is widely accepted. This paper argues that there are two important limitations to the evidence assembled in support of the underinvestment hypothesis: (a) many authors have compared the social rate of return to public investments with the private rate of return to private investments; (b) costs of public expenditures on agricultural research have been underestimated by a failure to account for the marginal excess burden of the tax collection system. Taking these two factors into account, evidence in support of the underinvestment hypothesis is weakened considerably.