Dissertationen: „Plant and animal science“

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Bagchi, Anita. „Plant and animal science in ancient India : perspective, attitude and conservation measures“. Thesis, University of North Bengal, 2009. http://hdl.handle.net/123456789/1529.

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Bingham, Troy J. „Plant and Animal Performance in Tall Fescue and Tall Fescue/Legume Pastures“. DigitalCommons@USU, 2014. https://digitalcommons.usu.edu/etd/2769.

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Tall fescue is the one of most common grasses in irrigated pastures throughout the Intermountain West. Two limitations of tall fescue are a decrease in productivity during hot summer months and the need for supplemental nitrogen (N). The objective of this research was to compare tall fescue-alfalfa (TF+ALF), tall fescue-birdsfoot trefoil (TF+BFT), tall fescue-nitrogen fertilizer (TF+N), and tall fescue without nitrogen fertilizer (TF-N) on forage yield, nutritional quality, and livestock performance. Research plots were established at the Utah State University Pasture Research Facility in Lewiston, UT in 2010 and grazed in 2012 and 2013. Treatments were arranged in a randomized complete block design with four replications and divided into four paddocks per replication. Three Angus crossbred steers with an average starting weight of 380 kg were placed on each treatment and rotated to a new paddock every 7 days. A put-and-take method was used throughout the growing season such that each paddock received 80% utilization. Four forage samples were collected from each paddock just prior to grazing using a 0.5 m2 quadrat for determination of dry matter (DM) and nutrient content. ADF, NDF, IVTD, and TDN were used to estimate nutrient content and steers were weighed every 28 days to determine livestock performance. Forage yield was highest (P<0.05) in TF+N (5164 kg ha-1), followed by the TF+BFT (4721 kg ha-1) and TF+ALF (4463 kg ha-1) treatments, whereas, the TF-N treatment had the lowest yield (2920 kg ha-1). In this study, TF+BFT (593 g kg-1) and TF+ALF (593 g kg-1) had a better (P≤ 0.05) season-long average TDN value than TF+N (558 g kg-1), which in turn was higher (P≤ 0.05) than TF-N (550 g kg-1). Steer average daily gains (ADG) were different (P<0.05) in every treatment with TF+BFT (0.73 kg d-1) being the highest, followed by TF+ALF (0.67 kg d-1), then TF+N (0.61 kg d-1), and similar to forage yield, TF-N had the lowest ADG (0.40 kg d-1). Tall fescue greatly benefits from added N whether via fertilizer or N transfer by legumes and this study showed that BFT and ALF mixed with TF increases plant and animal performance while reducing fertilizer costs and helps maintain a more environmentally sustainable pasture.

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Huynh, Mark D. „Targeted Sequencing of Plant Genomes“. BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4353.

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Next-generation sequencing (NGS) has revolutionized the field of genetics by providing a means for fast and relatively affordable sequencing. With the advancement of NGS, whole- genome sequencing (WGS) has become more commonplace. However, sequencing an entire genome is still not cost effective or even beneficial in all cases. In studies that do not require a whole-genome survey, WGS yields lower sequencing depth and sequencing of uninformative loci. Targeted sequencing utilizes the speed and low cost of NGS while providing deeper coverage for desired loci. This thesis applies targeted sequencing to the genomes of two different, non-model plants, Artemisia tridentate (sagebrush) and Lupinus luteus (yellow lupine). We first targeted the transcriptomes of three species of sagebrush (Artemisia) using RNA-seq. By targeting the transcriptome of sagebrush we have built a resource of transcripts previously unmatched in sagebrush and identify transcripts related to terpenes. Terpenes are of growing interest in sagebrush because of their ability to identify certain species of sagebrush and because they play a role in the feeding habits of the threatened sage-grouse. Lastly, using paralogs with synonymous mutations we reconstructed an evolutionary time line of ancient genome duplications. Second, we targeted the flanking loci of recognition sites of two endorestriction enzymes in genome of L. luteus genome through genotyping-by-sequencing (GBS). GBS of yellow lupine provided enough single-nucleotide polymorphic loci for the construction of a genetic map of yellow lupine. Additionally we compare GBS strategies for plant species without a reference genome sequence.

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Wilhelm, Amanda. „Investigation of the Toxicity and Toxicokinetics of Selenium from the Accumulator Plant Symphyotrichum spathulatum (Western Mountain Aster) in Sheep“. DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/553.

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This study was designed to observe the effects of selenium from plant material in sheep after a single, oral dose. Purified sodium selenite and selenomethionine were given as positive controls. The plant Symphyotrichum spathulatum (Western Mountain Aster) was collected, analyzed for selenium content, and administered orally to sheep at varying doses according to body weight. Clinical signs were observed for 7 days during which time whole blood, serum, and expired air were collected. Following euthanasia, tissues were collected for histopathological analysis and mineral analysis. Clinical signs were less apparent than expected and included depression and mild dyspnea in sheep receiving the highest doses of selenium as plant material, whereas pathologic lesions were prominent. Acute myocardial degeneration and necrosis was most severe in the highest dose animals, but present to lesser degrees as dose decreased. Pulmonary lesions of edema and congestion were less frequently observed. Thirteen animals died prior to study completion. Selenium concentration in tissues, brain, liver, kidney cortex, atrium, ventricle, and skeletal muscle, increased with increasing dose of plant material. Treatment had a significant impact on selenium concentration in all tissues collected for mineral analysis (P < 0.01). Whole blood and serum were collected to study the toxicokinetics of selenium in these sheep. Serum kinetic parameters that increased significantly with increasing dose included the elimination rate constant, peak selenium concentration, and area under the selenium concentration versus time curve. Serum kinetic parameters that significantly decreased with increasing dose included the absorption and elimination half-lives. Whole blood kinetic parameters that increased significantly with increasing dose included the elimination rate constant, peak selenium concentration, and area under the curve. Expired air was collected to study the respiratory toxicokinetics of selenium in the sheep. The selenium concentration in expired air from sheep receiving selenomethionine was significantly greater than all other treatments (P < 0.0001) at all collection time points. But an intriguing finding was the dramatic differences in elimination profile curves as selenium dose increased with the plant material. The highest dose group elimination curve continually increased through all collection time points. All other groups dosed with plant material saw a decrease in selenium elimination by the last collection time point.

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Pirone, Cary L. „Bilirubin: an Animal Pigment in the Zingiberales and Diverse Angiosperm Orders“. FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/336.

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Strelitziaceae is a tropical monocot family comprising three genera and seven species: Ravenala Adans and Phenkospermum Endl., which are monotypic, and five species of Strelitzia Aiton. All species produce woody capsular fruits that contain vibrantly colored arillate seeds. Arils of the Strelitzia species are orange, those of Phenakospermum are red, and those of Ravenala are blue. Unlike most plant pigments, which degrade after cell death, aril pigments in the family persist for decades. Chemical properties of the compounds are unusual, and do not match those of known pigment classes (carotenoids, flavonoids, betalains, and the chlorophylls). I isolated the orange pigment from the arils of Strelitzia nicolai, and performed HPLC-ESMS, UV-visible, 1H NMR and 13C NMR analyses to determine its chemical structure. These data indicated the pigment was bilirubin-IX, an orange-yellow tetrapyrrole previously known only in mammals and some other vertebrates as the breakdown product of heme. Although related tetrapyrroles are ubiquitous throughout the plant kingdom and include vital biosynthetic products such as chlorophyll and phytochromobilin, this is the first report of bilirubin in a plant, and evidence of an additional biosynthetic pathway producing orange coloration in flowers and fruits.

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Dal, Gobbo Alice. „Becoming-poor, becoming-animal, becoming-plant ... becoming-imperceptible : an ethnographic study of everyday energy assemblages in transition“. Thesis, Cardiff University, 2018. http://orca.cf.ac.uk/117613/.

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The 2008 financial crisis has meant for the West a much wider social, political and economic questioning of its underpinnings. This delicate contingency combines with an increasingly evident ecologic crisis, indissolubly related to the capitalist, post-industrial, consumer economy that cracked in 2008. As the latter is proving unsustainable on all these levels, there is space for challenging this economic system and its underpinnings: development, industrialism and infinite growth (via consumption). Governments are putting in place measures that aim at environmental change mitigation, but with too little effect. With my study, I investigate the potentiality of the everyday as a site of ecological resistance, difference and creation. As a way of pursuing this, I designed a multimodal and multimedia participant observation study, focusing on energy use in everyday life. The locale is a town in the North-East of Italy, Vittorio Veneto, an interesting example of a formerly affluent area strongly hit by the recession. As a contribution to existent literature in this field, I draw and expand upon recent reflections that seek to go beyond the limitations of constructionism as the guiding approach to critical qualitative social sciences investigations. This “post-qualitative” literature calls for more attention to the ways in which language and discourses are co-emerging with, and co-constitutive of, the material, affective and non-representational qualities of experience. In line with this, I give special attention to the desiring and unconscious dimensions of energy use and everyday life more generally. Nonetheless, these are not conceptualised as subjective, interior or personal – but rather as trans-human flows that traverse and shape the social world. In this sense, focussing on desire is also a way to address the political and power-ridden aspects of energy use, little addressed in current research. Inspired above all by the philosophy of Gilles Deleuze (also with Félix Guattari), I look at the ways in which (collective) desire shapes the energy “assemblages” that we live through in ordinary life. If the dominant (libidinal) economy gears towards hyper-consumption and intensive energy practices, are molecular desires being mobilised that evade such hegemony? To what extent are they capable of a radical creation of more ecologically sensitive, life affirmative, assemblages? By making treasure of the different affordances of multi-media representation of the field, in my thesis I map contemporary everyday energy assemblages as they are territorialised and deterritorialised along lines of (ecological) becoming. I bring attention not only to the chances, but also to the risks and contradictions of emerging “lines of flight” from our unsustainable economy. This critical reflection is also applied to the theory informing my own study and its potential pitfalls. Finally, I reflect on the politics and ethics of social sciences in participating to draw lines of transitions towards sustainability.

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Landeen, Melissa L. „Mountain Big Sagebrush (Artemisia tridentata ssp vaseyana) Seed Production“. BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5740.

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Big sagebrush (Artemisia tridentata Nutt.) is the most widespread and common shrub in the sagebrush biome of western North America. Of the three most common subspecies of big sagebrush (Artemisia tridentata), mountain big sagebrush (ssp. vaseyana; MBS) is the most resilient to disturbance, but still requires favorable climactic conditions and a viable post-fire seedbank for successful unassisted recovery. This study was designed to assess MBS seed production throughout post-fire recovery. We performed 2 pilot studies to develop methods for estimating seed production and plant age. The results of the pilot studies and a space-for-time substitution strategy were used to measure seed production on 13 sites ranging from 10-33 years post-fire. We hypothesized that seed rain (mean seeds produced/ m2) would peak before stand density had maximized due to decreasing individual plant fecundity (mean seeds produced/ plant) in high density stands. We measured population density and individual plant fecundity for three size classes of MBS and used forward stepwise regression analysis to identify environmental factors influencing seed production over time. Density for small (basal stem diameter (BSD) <1 cm) and medium-sized (BSD=1-3 cm) plants was consistently low and was not affected by time since fire (TSF), while large-sized (BSD > 3 cm) plant density increased steadily with TSF (p=0.0002). Plant fecundity decreased with TSF for all three size classes (p range = 0.019 – 0.0506), with large plants dominating reproductive output. Small and medium-sized plant fecundity was negatively correlated with winter precipitation (p range = 0.0106-0.0174), while large plant fecundity was positively correlated with winter precipitation (p<0.0001) and negatively correlated with elevation (p=0.0001). Despite losses in plant fecundity over time for all size classes, steady recruitment in population density resulted in increased seed rain (p=0.0039), suggesting that increases in stand density compensated for losses in individual plant fecundity. Results partially support our hypothesis that the time required for MBS seed rain to be maximized was not tightly bound to indicators of stand maturation. Understanding the factors that influence post-fire seed production can help land managers better manage for successful recovery by providing them with tools for evaluating seed production capabilities of MBS communities.

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Martin, Miriam Sharon. „Survey of Management and Marketing Practices on U.S. Cow-calf Operations and Evaluation of Different Captive Bolt Lengths in a Commercial Slaughter Plant“. Thesis, Colorado State University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10784935.

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Finding ways to objectively measure welfare within different sectors of the beef industry is necessary to continually improve cattle welfare from birth to slaughter. The first objective of Study 1 was to benchmark cow-calf producer perspectives on management strategies and challenges that ultimately affect cattle welfare on ranches in the United States. The second objective of Study 1 was to quantify how producers are marketing their calf crop, their priorities when selecting replacements, and if producers saw value in handling and care guidelines. A total of 1,414 responses from cow-calf producers in 44 states were collected through a survey done in partnership with BEEF Magazine. Thirty questions were asked of producers to gather demographic information, producers’ current handling and health management practices, and how they prioritized industry challenges. As well as establish at what age and through what avenue producers are marketing their calf crop, and gauge producer perspectives on a quality assessment outlining handling and care guidelines.

After analyses of producer responses, it was concluded that the frequency of management methods and decisions are impacted by age, operation size, location, and BQA certification. A higher percentage of respondents who were BQA certified used electronic eartags, followed by freeze branding. A higher percentage of respondents not BQA certified used basic eartags and hot branding. 74.5% of respondents were preconditioning their calf crop. A higher percentage of respondents were preconditioning their calf crop that were BQA certified, than those who were not BQA certified. The most important beef industry challenge identified was cow-calf health and the biggest challenge to producer’s own operation was identified as land availability/price. The most important animal health issues on producers’ operations were identified as Bovine Respiratory Disease, flies, Pinkeye, and reproductive health. By producer age, calf/neonate health was identified as the biggest challenge for respondents under the age of 30. Respondents age 55-70 responded that Veterinary Feed Directive (VFD)/regulations was more of a challenge than any other age group. Respondents with 50 head or less or more than 1,000 head more frequently retained their calf crop through finishing and respondents with 51 to 200 head and 201 head to 500 head more frequently backgrounded and then sold their calf crop. 13.5% of respondents answered yes, a veterinarian had offered to administer a drug for pain management when castrating or dehorning. Of those 13.5% who responded yes pain management had been offered, 54.55% of respondents chose to use a pain relief method. A higher percentage of producers that precondition also indicated that they use a pain relief method when castrating or dehorning more frequently, though it was still a low percentage. Overall, 46.3% of respondents saw value in handling and care guidelines and 54.9% of respondents saw value in a program including source and age verification, a vaccination plan, and handling and care guidelines. Respondents who were BQA certified, had a beef cow inventory of 501 to 1,000 head, who preconditioned their calves and backgrounded them before selling, and who lived in the West more frequently saw value in a quality assessment outlining handling and care guidelines.

The objective of Study 2 was to examine the effects of captive bolt length and breed type on post-stun leg activity in cattle. A total of 2,850 Holstein (HOL) and non-Holstein British/Continental bred (NHOL) steers and heifers were observed post-stunning at a large commercial slaughter facility. A penetrating pneumatic captive bolt stunner was used with three different bolt lengths: CON, 15.24 cm; MED, 16.51 cm; and LON, 17.78 cm. Hind limb kicking, forelimb activity, take away belt stops, carcass swing and number of knife sticks during exsanguination were recorded for each animal from video recording. Hind limb and forelimb kicks observed ranged from 0 to 25 and 0 to 8, respectively. A significant main effect of treatment, breed type and an interaction between treatment and breed type on hind limb activity was found. Analysis of post-stun hind limb and forelimb activity indicated that increasing pneumatic captive bolt length does not decrease post-stun leg activity but alternatively can increase kicking when using the longest bolt tested in particular types of cattle, i.e. Holsteins. Other parameters associated with the shackling and hoisting process were impacted by breed type as well. There was a higher percentage of cattle experiencing take away belt stops and carcass swing in HOL as compared with NHOL. (Abstract shortened by ProQuest.)

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Gardner, Eric T. „Arthropod and Plant Communities as Indicators of Land Rehabilitation Effectiveness in a Semi-arid Shrub-steppe“. BYU ScholarsArchive, 2008. https://scholarsarchive.byu.edu/etd/1733.

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We describe a case study evaluating the ecological impact of Bromus tectorum L. (cheatgrass) invasion following fire disturbance and the effectiveness of revegetation in improving ecological integrity in a degraded semi-arid shrub steppe system. The effectiveness of rehabilitation efforts was assessed from measurements of arthropod richness, vegetation and arthropod community composition, and ground cover characteristics in three habitats: undisturbed, burned and weed-infested (B. tectorum), and burned and rehabilitated with native and non-native vegetation. Arthropods were collected in each habitat using pitfall traps. Differences in arthropod richness were compared using rarefaction curves. Non-metric multidimensional scaling, and non-parametric multivariate statistical procedures including analysis of similarity and similarity percentages routines were used to compare arthropod and vegetation community composition and ground cover characteristics between habitats. Arthropod communities in the rehabilitated habitat were distinct from and intermediate to those observed in the undisturbed and weed-infested habitats. Rehabilitation in this instance resulted in an improvement in ecological integrity and perhaps an intermediate step on the way complete restoration. Arthropod richness, arthropod and vegetation community composition, and ground cover characteristics were all useful indicators of ecological integrity, but returned slightly different results. Assessing multiple variables yielded the most complete understanding of the habitats studied.

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Arzt, Alexandra E. „Dispersal: a multidisciplinary investigation of plant life“. VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/3957.

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Using plants as a basis for exploring the interstices between the human and nonhuman, this thesis investigates ideas of awareness, intelligence, deep time, animism, and the fluctuating human perception of the agency of Nature. It outlines environmental art practices since the 1950s involving vegetal life. In addition, the paper provides a critical analysis of plant perception of Jakob von Uexküll’s work and theories of vital materialism and “critical plant studies” while noting recent studies in plant neurobiology. In my work, plants become active participants via their movement, seeding, and smell. This study takes the form of imitation, purposeful symbiosis, anthropomorphism, and touch and uses an interdisciplinary practice involving various experiments, video, and plant life. In suggesting a new possible understanding of plants, the work argues for a new ecological ethos in a time when global warming weighs heavily on world policy and consciousness.

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Hollingshead, Andrew K. „Control of Alternaria solani Resistance to Boscalid, Fluopyram, and Chlorothalonil“. BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5720.

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Alternaria solani, cause of early blight, threatens potato yields. Fungicide resistance has made control of early blight difficult and there are concerns that in-season fungicide use results in resistance to boscalid, fluopyram, and chlorothalonil. Concern of high levels of resistance to boscalid a group 7 fungicide may confer cross-resistance to fungicides of the same group such as fluopyram. From 2014 to 2015, A. solani isolates were collected from field plots treated with boscalid, fluopyram, and chlorothalonil to test resistance levels. Isolates were determined resistant if EC50 values were higher than 5 µg ml-1. Boscalid and chlorothalonil mean EC50 values decreased two fold from 2014 to 2015, while fluopyram values increased two fold. A negative correlation between fluopyram and boscalid indicate no cross-resistance. Higher resistance levels to fluopyram (17.1 µg ml-1) were observed in the treatment C-14 where only fluopyram was applied in 2014. Treatments D-14 and D-15, only treated with chlorothalonil, had the highest mean EC50 values to chlorothalonil (2.3 and 1.1 µg ml-1, respectively). Field trials show fluopyram+chlorothalonil had lowest disease severity of 6.6 to 6.8%. Leaf residues of boscalid fluopyram, and chlorothalonil measured an average of 10.2, 4.9, and 55.0 ppm on leaves throughout the canopy. After 14 days average residues diminished to 0.74, 0.39, and 16.9 ppm for boscalid, fluopyram and chlorothalonil, respectively. Boscalid is not effective for early blight control because of high resistance; fluopyram resistance is increasing as treatments of fluopyram are applied; and chlorothalonil does not seem to be affected by continued fungicide application.

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Horn, Kevin J. „Factors Underlying Invasive Grass Fire Regimes in the Mojave Desert and its Consequences on Plant and Animal Communities“. BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/4172.

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Climate change and exotic plant invasions are significant anthropogenic threats to desert community structure and resilience . In the Mojave Desert, the invasive grass red brome (Bromusrubens L) is increasing fire frequency and extent in response to climatic factors. The resilience of this ecosystem will be affected by how plant and animal communities respond to fire. To better understand these dynamics, we studied the environmental factors underlying changes in invasive grass fire regimes in the Mojave Desert and its structural and functional effects on plant and animal communities. Following fire, reestablishment of native vegetation can be preempted by repeated burning associated with the abundant exotic grass red brome. Red brome density is correlated with various climate and landscape variables, but to establish causality, we experimentally assessed germination and growth of red brome. Red brome responded positively to fall precipitation, finer-textured soils, fertile-islands soils, and soils from burned landscapes. Red brome germination is maximized in wet fall periods when adequate water and optimal temperatures overlap . To evaluate landscape responses of pre- and post-fire plant communities and the potential for repeated burning we analyzed vegetation greenness (NDVI) data from 1985-2011 in response to temperature and precipitation. Landscape analysis indicated that the dominance of exotic grasses increases on post-fire landscapes. Following wet fall and winter seasons, high red brome productivity increases fire potential. Without mitigation, the establishment of an invasive-plant-driven fire regime is likely and may drive state transitions from arid shrublands to arid annual grasslands. Potential revegetation of post-fire landscapes will depend at least in part upon the physiological response of surviving vegetation to post-fire landscapes. Plant physiological responses to post-fire landscapes were generally neutral or positive, suggesting that revegetation of post-fire landscapes is not precluded by resource loss associated with fire and may even be enhanced by post-fire conditions. This will likely translate to increased reproductive potential of surviving plants. Alterations to small mammal populations will likely play a role in the reestablishment of vegetation (both native and exotics) as small mammals have strong top-down effects in arid ecosystems. Diversity and species richness responded negatively to burned landscapes as Merriam's kangaroo rat (Dipodomys merriami) increased in abundance while other species practically disappeared from burned landscapes. Merriam's kangaroo rat affects propagule sources through direct consumption, and seed dispersal. Increases in abundance and dominance of Merriam's kangaroo rat will likely alter plant recruitment.

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Duca, Radu Corneliu. „Food quality monitoring and analytical techniques optimization of some aliments within plant-animal correlation Contaminated aliments effects on the detoxication enzymes“. Phd thesis, Université Paris Sud - Paris XI, 2009. http://tel.archives-ouvertes.fr/tel-00447178.

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Zéaralénone (Zen) est un métabolite secondaire de type polykétide biosynthétisé par différentes espèces de Fusarium (Fusarium graminearum, F. culmorum, F. equiseti, et F. crookwellense). Il s'agit d'un oestrogène non-stéroïdien (ou mycoestrogène) souvent nommé phytoestrogène. La Zen est un contaminant de cultures de céréales dans le monde entier (Bennett et Klich, 2003). Elle résiste à la plupart des traitements qui ont lieu au cours de la fabrication des denrées alimentaires. En dépit de sa structure non-stéroïdienes, le zen est capable de se lier aux récepteurs des oestrogènes et provoque des altérations morphologiques et fonctionnelles des organes de reproductions. Elle interagit non seulement avec les deux types de récepteurs aux oestrogènes (Celius et al., 1999; Shier et al., 2001; Yu et al., 2004; Takemura et al., 2007), mais aussi avec les substrats dans un certain nombre d'insuffisance des enzymes hépatiques. La Zen est bien absorbée et est capable d'atteindre des cibles intracellulaires. La disparité importante des effets de la Zen entre les différentes espèces animales pourrait en partie due à la différence entre leur profil des enzymes hépatiques (Gaumy et al., 2001; Cavret et Lecoeur, 2006). Le métabolisme de la Zen est complexe, il est dominé par des réactions de conjugaison (considérées comme des voies de détoxication) et des réactions de réduction qui correspondent à l'activation biologique (Gaumy et al., 2001). Nos principaux objectifs étaient l'élucidation des effets des aliments contaminés (en particulier avec le zéaralénone) sur les enzymes de détoxication (en particulier CYP P450) et la compréhension des effets de la zéaralénone sur les différentes espèces. Dans la littérature l'effet de la Zen sur l'expression et sur l'activité des enzymes de détoxication est limité à des expériences in vitro, à notre connaissance aucune recherche in vivo n'a encore été publiée. En vue d'établir les effets in vivo de la zéaralénone sur les enzymes de détoxication nous avons effectué plusieurs expériences: tout d'abord sur le rat, qui est un modèle animal classique pour les études biologiques et sur lequel on trouve une large documentation sur les effets des xénobiotiques et en particulier sur les effets de la Zen, et ensuite sur le poulet, l'une des espèces considérée comme la plus résistante et «habituée» à la présence de la Zéaralénone. Des approches complémentaires ont été utilisées pour déterminer les effets de la zéaralénone sur les enzymes de détoxication: a) Le développement d'outils d'analyses pour des études de la pharmacocinétique des mycotoxines; b) la détermination in vivo des effets de la zéaralénone sur l'expression des enzymes de détoxication et de son devenir dans l'organisme animal c) du mécanisme moléculaire in vitro de la zéaralénone - les effets directs sur les enzymes de détoxification hépatique d) la spécificité des espèces et l'évaluation des risques humains. D'importants effets stimulants sur l'expression d'ARNm de la P-gp ont été observés in vivo chez le rat traitait avec Zéaralénone, ce qui suggère que la P-glycoprotéine pourrait être impliqué dans la voie de détoxication de la zéaralénone. L'implication de la P-glycoprotéine dans le transport de la Zen a été déterminé dans des lignées cellulaires Caco2 par Videmann et al., en 2008. La présence de zéaralénone induit des réponses métaboliques précoces et rapides, en particulier pour le CYP2C7, il pourrait jouer un rôle important dans la voie de détoxication de la Zen chez le rat. Une influence des traitements par la Zéaralénone sur l'expression des RNAm et sur l'activité des isoformes de P450, CYP2B2 et 3A a également été réalisée. CYP2C7 et CYP3A1 sont respectivement les homologues chez le rat des formes CYP2C8 et CYP3A4 humaine (Nelson, 1999), ces cytochromes sont impliqués dans la formation d'un nouveau métabolite le 8-hydroxy Zen. In vivo l'apparition de ce métabolite (le 8-hydroxy Zen) a également été démontrée. Le devenir dans le rat et le poulet de la Zéaralénone a été évalué en utilisant les nouvelles méthodes développées: HPLC-DAD et LC-MS (en utilisant comme étalon interne Zen 13C enrichi). Chez le rat, la zéaralénone est rapidement éliminée. Elle est retrouvée dans les urines, pendant les 6 premières heures après l'administration : environ 60% (47,8 ± 14,3 mg) du montant total de la zéaralénone urinaire éliminé (79,8 ± 23,9 mg) et la Zen et ses métabolites éliminés par l'urine sont d'environ 4% de la zéaralénone administrés. Dans les échantillons de muscle de poulet les niveaux d'α-Zol (13,42 mg / kg) sont plus élevés que le niveau JEFCA accepté (2 mg / kg). Ces volailles sont donc impropres à la consommation. A l'échelle mondiale l'évaluation des risques de l'exposition de l'homme à la zéaralénone, en prenant en compte les habitudes alimentaires, a été réalisée et il en résulte un important et constant risque pour la santé humaine. Aussi la nécessité d'apporter des modifications au règlement concernant la teneur maximale acceptable de la zéaralénone dans les céréales a était surligniez, et nous considérons comme acceptable la valeur 5 μg/kg.

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Buck, Joshua R. „Plant-Soil Feedbacks and Subalpine Fir Facilitation in Aspen-Conifer Forests“. BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3397.

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This thesis includes two studies. The first study examined changes in soil characteristics as a result of prolonged conifer dominance in successional aspen-conifer forests. Changing disturbance patterns in aspen-conifer forests appear to be altering successional dynamics that favors conifer expansion in aspen forests. The primary objective of this paper was to identify how increasing conifer dominance that develops in later successional stages alters forest soil characteristics. Soil measurements were collected along a stand composition gradient: aspen dominated, aspen-conifer mix, conifer dominated and open meadow, which includes the range of conditions that exists through the stages of secondary succession in aspen-conifer forests. Soil chemistry, moisture content, respiration, and temperature were measured. There was a consistent trend in which aspen stands demonstrated higher mean soil nutrient concentrations than adjacent meadows, mixed or conifer stands. Soil moisture was significantly higher in aspen stands and meadows in early summer. Soil respiration was significantly higher in aspen stands than conifer stands or meadows throughout the summer. The results indicate that soil resource availability and respiration peak within aspen dominated stands that are present during early succession and then decrease as conifer abundance increases along our stand composition gradient, representative of stand characteristics present in mid to late successional stages. Emerging evidence from other studies suggest that these observed changes in soil characteristics with increasing conifer dominance may have negative feedbacks on aspen growth and vigor. The second study examined the facilitation effect between aspen and subalpine fir establishment. In subalpine forests, conifer species are often found intermixed with broadleaf species. However, few if any studies have explored the existence and influence of facilitation between broadleaf tree species and conifers. We have observed the general establishment of subalpine fir seedlings at the base of aspen trees in a subalpine forest, indicating that a facilitative relationship may exist. To explore the potential facilitative relationship during secondary succession in subalpine forests, subalpine fir seeds were planted across a stand composition gradient (aspen dominated → mixed → conifer dominated stands) at six study sites in the Fishlake National Forest. Seeds were placed during the fall of 2010, at distances of 0 cm and 25 cm in each cardinal direction at the base of mature aspen and subalpine fir trees in each of the three stand types. Seeds were also planted within stand interspaces and in adjacent meadows. Seedling emergence was recorded at the beginning of the summer of 2011 and seedling mortality was recorded in October 2011. Soil moisture content was measured at the position that seeds were placed during the summers of 2009 and 2011. Aspen dominated stands had subalpine fir germination that was on average 11 times greater than mixed or conifer dominated stands. Germination was 2.3 fold greater at the base of aspen trees than fir trees and two fold greater at the base of aspen trees than interspaces. Seedling mortality was lower in aspen stands but was not significantly influenced by position relative to mature trees. Soil moisture was highest in aspen dominated stands, with better soil moisture conditions at the base of aspen trees and in interspaces compared to the base of fir trees. Few if any studies regarding conifer facilitation have provided evidence for facilitation at the germination life stage, rather they focus on seedling survival. However, our study illustrates a strong facilitative interaction in which both aspen dominated stands and aspen trees increase the likelihood of subalpine fir seedling establishment by drastically increasing rates of subalpine fir germination. Because of aspen's primary role in initiating secondary succession through post-disturbance sucker regeneration, and the subsequent dependence of conifers on aspen for establishment, aspen mortality via competition with conifers under longer fire cycles, droughts, or intensive ungulate browsing may result in a loss of aspen-conifer forest communities in some locales.

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Junger, Ashley. „Can this burger save the planet? : synthetic beef and the dream of an American animal-free diet“. Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119972.

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Thesis: S.M. in Science Writing, Massachusetts Institute of Technology, Department of Comparative Media Studies/Writing, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 22-26).
Sustainable food movements are focused on reducing meat consumption for one simple reason: meat is extremely environmentally costly. This enormous resource use by one industry makes it an appealing target for those looking to reduce American resource use. As a result, many are looking at ways to make livestock more sustainable. And there are two main ways to do so. Clover Food Lab represents one idea: a return to local farming with an emphasis on a plant-based diet. Impossible Foods is the second: using biotechnology to provide a sacrifice free alternative, synthetic beef. These companies aren't solutions in of themselves, but proposals on the way solutions should be implemented. The partnership between these two opposing strategies reveals the promises and pitfalls of trying to reform the American diet and, most importantly, that above all else our food system is unsustainable as it is now.
by Ashley Junger.
S.M. in Science Writing

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Chun, Elizabeth M. „Developing a Recombinant Plant Virus Nanoparticle Vaccine for Rift Valley Fever Virus“. Scholarship @ Claremont, 2019. https://scholarship.claremont.edu/scripps_theses/1345.

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Rift Valley Fever (RVF) is an emerging infectious disease found in both livestock and humans. RVF is associated with high abortion and mortality rates in livestock and can be fatal in humans. As such, RVF is economically and socially significant to affected smallholder and subsistence farmers, those infected, and national livestock industries. However, Rift Valley Fever virus (RVFV) vaccines are not commercially available outside of endemic areas or for humans, and current vaccines are limited in their safety and efficacy. A plant-based, viral nanoparticle vaccine offers a more affordable alternative to conventional vaccines that is safe, rapidly producible, and easily scalable, better meeting the needs of impacted communities. This project focuses on assessing the potential of using a Nicotiana benthamiana plant expression system to generate recombinant tobacco mosaic virus (TMV) nanoparticles displaying RVFV glycoprotein epitopes. Eight TMV-RVFV glycoprotein constructs were designed. Five TMV-RVFV constructs were successfully cloned, and four recombinant TMV constructs were successfully expressed in planta. The antigenicity of these constructs was examined for their possible use in RVFV vaccine development.

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Auman, Brian S. „Livestock as Seed Disseminators for Reseeding Degraded Rangelands: The Role of Dung in Gap Formation and Plant Establishment“. DigitalCommons@USU, 1996. https://digitalcommons.usu.edu/etd/6490.

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Livestock (cattle and sheep) were examined as seed disseminators for reseeding degraded Intermountain rangelands. "Hycrest" crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult. X A. cristatum (L.) Gaert.] seed was fed to yearling Holstein steers and Suffolk ewes. Dw1g was collected from each animal type and deposited on plots of high and low densities of an annual [cheatgrass (Bromus tectorum L.)] and perennial [squirreltail (Sitanion hystrix Nutt.)] grass species. The experiment evaluated the ability of the dung to suppress the resident vegetation, and the recruitment and establishment of Hycrest seedlings emerging from the dung. Sheep dung had little suppressive effect on resident vegetation and did not provide Hycrest with a favorable microsite for germination and establishment. Cattle dung provided favorable conditions for germination of Hycrest on all plots, but seedlings were unable to compete with either high or low densities of cheatgrass. Hycrest seedlings emerging from cattle dung were more successful in establishing on squirreltail plots, and most successful in establishing on the control plots (bare ground). Cheatgrass plants located near cattle and sheep dung benefited from an input of nutrients and a gapformation (with cattle dung), which translated into greater plant height, weight, and fecundity. The squirreltail plants did not show any noticable advantages gained from adjacent dung deposition. Even though cheatgrass was suppressed by cattle dung on the surface, its roots proliferated in the soil profile immediately under the cattle dungpat to levels equal to that found in other areas within the plots.

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Gordillo, Luis F. Jr. „Identification and Manipulation of Resistance to Tomato Spotted Wilt Virus Derived From Solanum peruvianum“. BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/2180.

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The domesticated tomato Solanum lycopersicum (L.), formerly known as Lycopersicon esculentum is a genetically well-studied crop species with high-density linkage and molecular maps based on crosses done between cultivated tomato and its distant related wild species. Wild tomato species harbor a wealth of resistance to many pathogens that have been introgressed into domesticated tomato for genetic control of diseases and pests and for improvement of many agronomic traits. The wild tomato S. peruvianum (L.) is the source of the Sw-5 gene, characterized and mapped to chromosome 9 of the tomato genome and introgressed into elite tomato germplasm, providing resistance to the tospovirus Tomato spotted wilt virus (TSWV). TSWV has been reported to be a major problem for tomato growers in many parts of the world, which in some cases, has resulted in tomato fields having been abandoned for some time. Additionally, there are reports that new races of TSWV have evolved that overcome Sw-5. TSWV replicates in both, plant cells and in the alimentary canal cells of thrips and then transmitted to plants by this insect acting as a vector. Both, TSWV and thrips have co-evolved to infest and infect more than 1090 plants species in over 100 families, thrips becoming resistant to pesticides and easily escaping by hiding deep in plant parts. World trade has disseminated thrips all over the world and environmental pressures have forced TSWV to recombine its RNA to overcome new resistance.

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Parker, Adam Calvin. „Evidence of Ancient Maya Agriculture in the Bajos Surrounding Tikal, Guatemala“. BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5784.

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Current Central American agricultural practices are environmentally and economically unsustainable, yet the ancient Maya who lived in the same region thrived for thousands of years. Archaeologists have attempted to understand the factors enabling the prolonged success and ultimate collapse of the Maya societies. Some have proposed that the karst seasonal wetlands, called bajos, that border many Maya sites in the region were an influential factor in the Maya's ability to flourish. For the past decade, researchers have used carbon isotope analyses to identify areas of ancient maize agriculture at Maya archaeological sites. In this study, we collected soil samples from bajos and upland areas at Tikal, one of the most prominent Maya sites, located in northern Guatemala, and analyzed the samples for evidence of past C4 vegetation. Our results confirm that bajos were utilized by the ancient Maya for long-term maize cultivation. Additionally, they suggest that modern agricultural methods in Guatemala that strategically utilize bajos may improve productivity and sustainability.

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Picard, Sophie. „Les Phénolglucosides dans la feuille de peuplier : identification, dosage, synthèse et propriétés physico-chimiques : rôle dans l'interaction plante-insecte“. Orléans, 1994. http://www.theses.fr/1994ORLE2030.

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Les Phénolglucosides présents dans les feuilles de peuplier semblent jouer un rôle déterminant dans l'interaction plante insecte. Différentes méthodes de conservation du matériel végétal, d'extraction, d'analyses par CLHP couplée à un détecteur DEDL et d'identification ont permis de définir avec certitude la composition en phénolglucosides de cinq clones sélectionnes comme modèles de référence pour une étude de la résistance aux attaques des chrysomèles C. Tremulae et C. Populi. Parallèlement, l'association du protocole d'extraction et d'une technique chromatographique de purification a conduit à l'obtention à l'échelle préparatoire des principaux phénolglucosides caractéristiques de ces clones et plus particulièrement d'une nouvelle substance naturelle, la deltoïdine. Un certain nombre de ces phénolglucosides et différents dérives o-acyles de la salicine ont été synthétises selon plusieurs stratégies de o-acylation régiospécifique en position 2' sur le glucose ou en position 7 sur l'aglycone de la salicine. Les tests alimentaires réalises in vitro ont permis de confirmer l'influence des phénolglucosides sur le comportement des chrysomèles et principalement le rôle anti-appètent de la tremuloidine du probablement à la 2'-o-benzoylation du glucose. Par ailleurs, la réalisation in vivo d'attaques naturelles et mécaniques de jeunes plants a permis de mettre en évidence d'une part une augmentation de la concentration en tremuloidine, significative de l'existence d'un système de défense induite, et d'autre part que seule l'attaque naturelle des chrysomèles est susceptible de déclencher un mécanisme d'auto-défense de l'arbre, avec propagation du phénomène aux rameaux voisins

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Young, Kert R. „Plant Establishment and Soil Microenvironments in Utah Juniper Masticated Woodlands“. BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3318.

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Juniper (Juniperus spp.) encroachment into sagebrush (Artemisia spp.) and bunchgrass communities has reduced understory plant cover and allowed juniper trees to dominate millions of hectares of semiarid rangelands. Trees are mechanically masticated or shredded to decrease wildfire potential and increase desirable understory plant cover. When trees are masticated after a major increase in tree population density and associated decrease in perennial understory cover, there is a risk that invasive annual grasses will dominate because they are highly responsive to the increased resource availability that commonly follows removal of the main resource user. To determine if tree mastication increases resource availability and subsequently favors invasive annual or perennial grasses, we compared soil temperature, water, and nutrient microenvironmental conditions and seedling establishment and growth. We used the major rangeland weed, cheatgrass (Bromus tectorum L.), to represent invasive annual grasses and Anatone bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) A. Löve), a natural accession of native bluebunch wheatgrass, to represent the perennial grasses of the sagebrush-bunchgrass plant community. These comparisons were made between and within paired-adjacent masticated and untreated areas at three locations in Utah dominated by Utah juniper (Juniperus osteosperma (Torr.) Little). Juniper tree mastication generally increased resource availability with masticated areas having greater soil temperature, soil water availability, and soil N supply rates than untreated areas. Prior to juniper tree mastication litter mounds were not found to be resource islands probably because juniper trees themselves were using subcanopy soil water and nutrients. After juniper tree mastication and elimination of these predominant resource users, litter mounds served as resource islands with greater soil water availability and N supply rates than bare interspaces during the critical time for seedling establishment in spring. Plant growth followed in line with greater resource availability after tree mastication with masticated areas having more productive although fewer invasive-annual and perennial grass seedlings than untreated areas. These results suggest that increases in resource availability and warmer spring temperatures associated with mastication will not necessarily favor invasive annual over perennial grass seedling establishment. Resilience of the sagebrush-bunchgrass community to return to dominance after juniper control will likely be greatly influenced by how much of the sagebrush-bunchgrass community remains following tree control and the intensity of propagule pressure by invasive species. If only invasive annuals remain when the trees are treated then invasive annuals would be expected to dominate the post-treatment plant community especially with their ability to establish inside litter mounds unless they were also controlled and perennial grasses planted at the time of treatment.

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Owens, Jacob Michael. „Influence of Supplemental Legumes that Contain Tannins and Saponins on Intake and Diet Digestibility in Sheep Fed Grasses that Contain Alkaloids“. DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/174.

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My objectives were to determine if nutritional benefits occur when animals are offered foods with compounds -- alkaloids, saponins, and tannins - that are potentially complementary. I hypothesized that food intake and digestibility increase when lambs consume plants such as alfalfa ALF that contain saponins or birdsfoot trefoil (BFT) that contain tannins when the basal diet is endophyte-infected tall fescue (TF) or reed canarygrass (RCG) both of which contain alkaloids. I predicted that the nutritional status of lambs would be enhanced if basal diets of alkaloid-containing grasses were supplemented with ALF or BFT. Lambs fed a basal diet of either endophyte-infected TF or RCG ate more food and consequently digested more dry matter, energy and nitrogen when supplemented with ALF or BFT. Lambs ingested more dry matter and digested more nutrients when fed a basal diet of RCG than one of TF, and supplementing with ALF and BFT was more beneficial for lambs fed TF than for lambs fed RCG. Increased intake of digestible nutrients was due to greater intake when lambs were offered more than one food, not due to an increase in digestibility. In pen trials meant to complement the field trials, lambs were offered an alkaloid-containing (either gramine or 5-methoxy-N,N-dimethyltryptamine) total mixed ration and supplemented with a food that contained saponins or tannins. All rations were isocaloric (3.3Mcal/kg) and isonitrogenous (14% CP). Lambs fed a ration with either alkaloid and offered a food containing saponin digested approximately the same amount of dry matter, energy, nitrogen, and NDF as lambs not offered saponin. When lambs were fed a ration with either alkaloid and supplemented with food that contained tannins, tannin consumption adversely affected dry matter, energy, and NDF digestibility, but lambs offered food with tannins increased dry matter intake, and as a result, they digested the same amount of dry matter, energy, and NDF as lambs not offered the food with tannins. Lambs offered tannin digested and retained more nitrogen than lambs not offered tannin. These findings indicate a nutritional advantage for sheep eating mixtures as opposed to monocultures of foods with different profiles of secondary compounds and nutrients.

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Buck, Rachel Lynn. „Importance of Placement Depth in Evaluating Soil Nitrogen, Phosphorus, and Sulfur Using Ion Exchange Resin Capsules in Semi-Arid, Low Fertility Soils“. BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/4293.

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Ion exchange resin capsules provide a possible alternative to conventional soil testing procedures. Previous studies with semi-arid, low fertility soils observed poor relationships with poorly mobile nutrients such as phosphorus (P). We propose that placement depth may improve those relationships. Our objective was to (1) determine if placement depth could improve resin capsule estimation of the bioavailability of nitrogen (N), P, and sulfur (S) and (2) to determine if resin capsules can effectively estimate S availability in semi-arid, low fertility soils. Field sites were established in Rush and Skull Valleys, Utah on loam and sandy loam soils, respectively. Fertilizer was surface applied as ammonium sulfate and triple superphosphate with six N, P and S treatments (0, 5.5, 11, 22, 44 and 88 kg ha-1 of N and P2O5 and 0, 7, 14, 28, 56 and 112 kg ha-1 of S). Thirty 4.0-m2 plots were established at each field location. Resin capsules were placed three per plot at 0–5, 5–10, and 10–15 cm deep in the soil and soil samples taken at respective depths. The capsules were removed and replaced after approximately 90 d. Final removal and soil sampling occurred approximately 240 d later. For the second study, fertilizer was surface applied as ammonium sulfate with six S treatments (0, 7, 14, 28, 56 and 112 kg ha-1 of S) with one resin capsule placed in each 4.0-m2 plot at a depth of 5 cm in the soil. Resin capsules were removed and replaced approximately every 90 d for a total of four samplings. Soil samples were taken with every resin capsules install and removal. In the first study, bicarbonate extractable P was significantly related to P application at all depths and times except the two lowest depths at the time of final sampling, and resin capsule P was only related to P application 398 days after application in the 0–5 and 5–10 cm depths. However, this is an improvement in estimates of bioavailability compared to a single placement depth. The 5–10 cm depth was the best for placement for determination of NH4-N, and resin capsules improved upon soil test estimates. For NO3-N, depth was not important, but resin capsules had a stronger relationship with N applied than the soil test 398 d after application. In addition, both resin capsules and the S soil test were related to S applied, but resin capsules were more able to pick up S cycling through the system. In the second study resin capsules and conventional soil tests were both effective in distinguishing between fertilizer rates, though only the conventional soil test was related to S applied at the last sampling (366 d after fertilizer application). Overall resin capsules were effective at reflecting application rates, and may be a good tool to estimate nutrient bioavailability. Correlation with plant uptake is required to determine if soil tests or resin capsules were a better estimate of bioavailable nutrients.

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Jones, Mary Pletsch. „Evaluating Nutrient Availability in Low Fertility Soils With Resin Capsules and Conventional Soil Tests“. BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/3049.

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Commonly used soil analysis and resin capsule procedures are used to assess nutrient status in fertile soils, but their validity in semi-arid ecosystems is unknown. Three studies were performed to assess resin capsule effectiveness in semi-arid ecosystems. An incubation study was completed in which loamy sand and sandy clay loam soils were treated with rates of N, P, Fe and Zn. Each soil treatment was implanted with a resin capsule and incubated for 60 or 120 days. Resin capsules reflected NH4-N and P fertilizer at low rates in the loamy sand. NO3-N reflected rates in both soils, but did not reflect Fe or Zn application. Resin capsule NH4-N was a better indicator than KCl-extractable NH4-N, but resin capsule NO3-N was not as effective as water extraction, and resin capsule P was poor compared to NaHCO3-P. A second study was performed in glasshouse conditions using the incubation study soils. Soils were treated with rates of N, P and resin capsules were placed in pots. Pots were seeded with squirreltail grass (Elymus elymoides) and placed in a glasshouse. Resin capsules were removed at 120 days, soil samples taken, grass harvested and yield measured. Yield and total nutrient removal was correlated to resin NH4-N, marginally related to resin or soil NO3-N, and unrelated to resin P. Yield and total nutrient removal was correlated with application rates and resin NH4-N and NaHCO3-extracted P. The third field study, compared two sites with rates of N and P application were established on clay loam and sandy loam soils. Resin capsule and conventional soil tests for NO3-N, NH4-N and P were measured and plant nutrient status examined. Resin capsules were removed and replaced and soil samples taken every 90 days. Resins P was not related to P application or to plant tissue P but NaHCO3-extracted P was, while resin NO3-N, KCl-extracted NO3-N and NH4-N were correlated to N application and plant N. Soil test P was more effective in predicting P status and bioavailability than resin capsules. Resin NH4-N and NO3-N predicted N status and bioavailability, but soil tests were just as effective in semi-arid conditions.

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Ng, Terry Fei Fan. „Discovery of Novel Viruses From Animals, Plants, and Insect Vectors Using Viral Metagenomics“. Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3506.

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Understanding emerging viruses is critical for disease monitoring and prediction; however, surveys of novel viruses are hindered by the lack of a universal assay for viruses. Viral metagenomics, consisting of viral particle purification and shotgun sequencing, is a powerful technique for discovering viruses in a wide variety of sample types. However, current protocols are not effective on tissue samples (e.g., lungs, livers and tumors), where they are hindered by the high amount of host nucleic acids which limits the percentage of sequences that originate from viruses. In this dissertation, a modified viral metagenomics protocol was developed and utilized to effectively purify viruses from tissues, enabling the sequencing of novel viruses from animals, plants, and insect vectors. Viral metagenomics performed directly on tissue samples enabled the discovery of novel vertebrate, plant, insect and bacterial viruses. From a sea turtle fibropapilloma, viral metagenomics revealed a novel tornovirus STTV1, which is only the second single-stranded DNA virus known in reptiles and is extremely different from any previously described viruses. Similarly, from the lung of a sea lion involved in a mortality event, viral metagenomics identified a novel sea lion anellovirus (ZcAV), which is the first anellovirus characterized from a marine animal. The STTV1 and ZcAV genomes were highly divergent from known viruses, to a degree that they could not have been detected by degenerate PCR assays or microarrays, demonstrating viral metagenomics as an effective method for characterizing novel viruses. In addition to discovery of viruses in individual diseased animals, this dissertation pioneered a technique called vector-enabled metagenomics (VEM) to examine viruses present in insect vectors. VEM combines the power of metagenomics to sequence novel viruses with the ability of insect vectors to integrate viral diversity over space, time, and many host individuals and species. VEM allows for the investigation of viral diversity among the broad range of hosts that the insects feed on, providing an unprecedented snapshot of the viral diversity in natural reservoirs. This dissertation describes the first viral metagenome performed on mosquitoes and whiteflies, providing significant insights to the viral diversity in animal and plant reservoirs. Both animal and plant viruses were represented in the mosquito viromes, which likely originate from animal blood and plant nectar that the mosquitoes feed on. Mosquito viromes contained a diverse range of viruses, including vertebrate, insect, plant, and bacterial viruses, and almost all the viral sequences were novel, suggesting the pan-animal virome is largely uncharacterized. In contrast, only plant viruses were observed in the whitefly viromes because whiteflies feed solely on plants. Whitefly viromes contained known and novel viral sequences infecting crops, novel viral sequences infecting native plants, as well as novel satellites that were the first viral satellites to be documented in North America. Distinct viromes were found amongst the three mosquito samples as well as between the two whitefly samples, demonstrating the diverse and dynamic nature of the viruses in plant and animal reservoirs. By enabling the discovery of virus in diseased organisms and in insect vectors, viral metagenomics is a powerful technique that will significantly enhance our fundamental scientific understanding of the diversity, transmission, biogeography, and emergence of viruses. The viral metagenomic approach described here has implications for surveillance of emerging viruses, prediction of viral epidemics, and proactive control of diseases.

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Hellberg, Lou. „Communicating Sustainable Consumption?: How the Environmental Impact of Animal-Based Food Consumption is Expressed by Swedish Environmental Non-Governmental Organizations“. Thesis, Malmö universitet, Fakulteten för kultur och samhälle (KS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-21923.

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The demand and consumption of food products created by the livestock- and fishing industries, have a major environmental impact, affecting climate change, biodiversity, and ecosystems. Yet, there seems to be a lack of public awareness of the direct impact one’s choice of food has on the environment, which suggests that more effective efforts are needed in order to introduce the concept to consumers. By the influence of a post-humanist perspective, this thesis investigates how the environmental impact of consuming animal-based food is communicated by Swedish environmental non-governmental organizations, and how the organizations are actively working to change consumers’ dietary habits by selecting more sustainable options. The research has focused on the external communication channels of the organizations, where verbiage and imagery have been analyzed in context, by using an analytical perspective of a constructionist view of communication, of where I acknowledge that communication has changed in our digital society. The findings indicated that the organizations are showing clear efforts and willingness of communicating the environmental impact of consuming animal-based food, although these efforts remain quite limited. The promotion of a plant-based diet as a way to help mitigate climate change was also communicated to a fair extent, but the organizations seemed to be privileging the preferences of consumers for animal-based food products over the actual need for them. Given that scientific evidence has shown that human consumption of animal-based food products has a major environmental impact, the overall produced knowledge by the organizations’ communication of consuming such products is still lacking. This suggests that more effective communication efforts are still needed, given the severity of the issue, which requires a drastic social change in eating habits as currently practiced in developed nations, in order to effectively mitigate climate change.

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Badrakh, Turmandakh. „Effects of Abscisic Acid (ABA) on Germination Rate of Three Rangeland Species“. BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5881.

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Seeds sown in the fall to restore sagebrush (Artemisia spp.) steppe plant communities could experience high mortality when they germinate and seedlings freeze during the winter. Delaying germination until the risk of frost is past could increase seedling survival. We evaluated the use of abscisic acid (ABA) to delay germination of Elymus elymoides, Pseudoroegneria spicata, and Linum perenne. The following treatments were applied: uncoated seed, seed coated with ABA at 2.2, 4.4, 8.8, 13.2, and 17.6 g of active ingredient kg-1 of seed, and seed coated with no ABA. The influence of seed treatments on germination were tested at five different incubation temperatures (5-25°C). The lowest application rate of ABA had no significant influence on germination percentage but higher application rates showed a decline. All concentrations of ABA tested delayed germination, especially at low incubation temperatures. For example, the time required for 50% of the seeds to germinate at 5°C was increased with the use of the lowest ABA application rate by 56, 61, and 14 days, for E. elymoides, P. spicata, and L. perenne, respectively. Quadratic thermal accumulation regression models were developed for each species and treatment to predict progress toward germination. For the two grasses, models had sufficient accuracy (R2 = 0.61- 0.97) to predict germination timing using field seedbed temperatures. Equations for L. perenne were less accurate (R2 = 0.03-0.70). Use of these models will allow testing whether ABA will delay germination sufficiently to avoid winter frost periods and provide the basis for future field tests.

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Heinken, Thilo, und Eckart Winkler. „Non-random dispersal by ants : long-term field data versus model predictions of population spread of a forest herb“. Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2010/4648/.

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Myrmecochory, i.e. dispersal of seeds by ants towards and around their nests, plays an important role in temperate forests. Yet hardly any study has examined plant population spread over several years and the underlying joint contribution of a hierarchy of dispersal modes and plant demography. We used a seed-sowing approach with three replicates to examine colonization patterns of Melampyrum pratense, an annual myrmecochorous herb, in a mixed Scots pine forest in northeastern Germany. Using a spatially explicit individualbased (SEIB) model population patterns over 4 years were explained by short-distance transport of seeds by small ant species with high nest densities, resulting in random spread. However, plant distributions in the field after another 4 years were clearly deviating from model predictions. Mean annual spread rate increased from 0.9 m to 5.1 m per year, with a clear inhomogeneous component. Obviously, after a lag-phase of several years, non-random seed dispersal by large red wood ants (Formica rufa) was determining the species’ spread, thus resulting in stratified dispersal due to interactions with different-sized ant species. Hypotheses on stratified dispersal, on dispersal lag, and on non-random dispersal were verified using an extended SEIB model, by comparison of model outputs with field patterns (individual numbers, population areas, and maximum distances). Dispersal towards red wood ant nests together with seed loss during transport and redistribution around nests were essential features of the model extension. The observed lag-phase in the initiation of non-random, medium-distance transport was probably due to a change of ant behaviour towards a new food source of increasing importance, being a meaningful example for a lag-phase in local plant species invasion. The results demonstrate that field studies should check model predictions wherever possible. Future research will show whether or not the M. pratense–ant system is representative for migration patterns of similar animal dispersal systems after having crossed range edges by long-distance dispersal events.

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Achu, Nina Cristóbal. „Determination of the botanical and chemical composition of the pasture diet selected by llamas (Lama glama) during the rainy season in the community of Pujrata“. BYU ScholarsArchive, 2003. https://scholarsarchive.byu.edu/etd/5324.

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Llamas (Lama glama) take advantage of poor natural forage (grasses and others) due to their efficient digestive physiology that is adapted for this type of forage. The problem now faced is the gradual exhaustion of the native grassland (low phytomass production). The vegetation does not cover the dry matter consumption requirements, and less so the nutrient requirements, of these animals. Because of this there is the necessity of determining the botanical composition, pasture selection by plant parts, and chemical composition of what llamas ingest in order to improve these animals' nutrition in the pasture. This study occurred at the Larqa Uma ranch, located on Cachaca hill, north of the community of Pujrata, Santiago de Callapa municipality, Pacajes province, department of La Paz. It is located between 4390 and 4530 meters above sea level, at 17° 14' South latitude by 68° 18' West longitude. The botanical composition, plant parts, and chemical composition (organic matter content, raw protein, and neutral detergent fiber) of pastured llama ingestions were determined on the reserved pasture and the pasture with native grasses during February, March, and April in the rainy season. Three male q'ara-variety llamas of three ages were used. They were fistulated at the esophagus to collect ingestion samples. Determination of botanical composition of the ingestions was done by the point stereoscopic technique (Heady and Torrel 1959), and the chemical composition by Proximal Weende analysis (organic matter and raw protein) and the Van Soest method (neutral detergent fiber). The variance analysis showed highly significant differences for the botanical composition of llama ingestions by pasture groups (p<0.05) and significant differences for the monthly evaluation interaction with pasture groups (p<0.05). Meanwhile, the month of evaluation, pasturing site, monthly evaluation interactions with pasturing site, pasturing site with pasture groups, and month of evaluation with pasturing sight with pasture groups did not have significant differences (p>0.05). The llamas selected 80.13% grasses, higher than the other pasture groups: 8.64% for grassoids and 8.63% herbs, which were selected in similar proportions (p>0.05). Statistically, there are no differences between these pasture groups found in llama ingestions. Shrubs contributed a very low proportion of ingestion (2.86%). Selection for grasses (84.95%) during February was higher than the month of April and similar to March. In contrast, the March average of 80.62% is similar to the first month and higher than in April (74.83%). Shrub consumption of 4.36% during April was higher than in February and similar to in March. March's average of 3.92% is similar to the last month and higher than in February (0.20%). During February, March, and April, grass consumption by llamas (84.95%, 80.62%, and 74.83%, respectively) was higher than the average consumption of the other pasture groups. Grassoids, herbs, and shrubs were selected in similar proportions (p>0.05). The variance analysis showed highly significant differences for selection for parts of the plants, interaction between the evaluation month with parts of the plant, and interaction of pasturing site with plant parts (p<0.05).

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Cromer, Elaina. „A Comparative Analysis of the Nutrient Composition and Digestibility of California Perennial and Annual Grasses at Four Stages of Growth“. DigitalCommons@CalPoly, 2017. https://digitalcommons.calpoly.edu/theses/1787.

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Beef products represent the fourth largest agricultural commodity in the state of California, valuing more than $3 billion from 2013 to 2015 (CDFA, 2016) and procure 90% of the income for the range livestock industry (FRAP, 2003). Forages found on California’s coastal, desert, foothill, and mountain ranges are the basis of the state’s beef cattle industry. Understanding their nutritional quality of these forages is important for their effective use (George et al., 2001a; Waterman et al., 2014). The objectives of this research were to investigate the nutritional characteristics, and in situ digestbilities in Angus beef cattle, of common California annual and perennial grasses: wild oats (Avena barbata and Avena fatua), soft chess (Bromus hordeaceous), filaree (Erodium botrys), Italian ryegrass (Lolium multiflorum), blue wildrye (Elymus glaucus), creeping wildrye (Leymus tritichoides), melic (Melica californica, Melica imperfecta, Melica torreyana), foothill needlegrass (Nasella lepida), purple needlegrass (Nasella pulchra). Nutritional composition as a percentage of dry matter (crude protein, CP; neutral detergent fiber, NDF; acid detergent fiber, ADF; and acid detergent lignin, ADL) and digestibilities were compared at four growth stages: late vegetative (LV), early reproductive (ER), late reproductive (LR), and dry (D). Plant samples were collected in San Luis Obispo County, CA. Crude protein concentrations decreased, and fiber concentrations increased, with maturity (P ≤ 0.05). Perennial grasses contained more NDF and ADF than annual grasses, across all growth stages (P ≤ 0.05). Annual grasses were significantly higher than perennials in dry matter digestibility (%DMD) at the 48 h incubation, when averaged across all growth stages (P ≤ 0.05); and at the LR and D stages, when averaged across all incubation periods (P ≤ 0.05). Within the annual grasses, %DMD was similar between ER, LR, and D stages. Within the perennial grasses, %DMD was similar between the LR and D stages (P ≤ 0.05).

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Taylor, Victoria A. „PHYSIOLOGICAL CHANGES ASSOCIATED WITH PREGNANT OR NONPREGNANT MARES GRAZING PASTURES OF ORCHARDGRASS-BLUEGRASS, KENTUCKY 31 TALL FESCUE INFECTED WITH EPICHLOË COENOPHIALA, OR KYFA9821 TALL FESCUE INFECTED WITH THE NOVEL ENDOPHYTE AR584“. UKnowledge, 2017. https://uknowledge.uky.edu/gluck_etds/33.

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Kentucky 31 tall fescue (KY31) infected with the common toxic endophyte strains of Epichloё coenophiala produces toxic alkaloids that improve plant vigor, but cause numerous adverse effects in grazing animals. Researchers developed a variety of KY31 containing an alternative strain of E. coenophiala, termed novel endophyte (NE). Adverse health effects in mares have not been evaluated. Experiments in this thesis tested the hypothesis that the NE pasture does not cause adverse effects typically associated with KY31. Specific aims were to: 1) compare forage ergovaline concentrations between KY31 vs NE pastures; 2) evaluate palmar artery diameters in mares grazing KY31, NE, or orchardgrass-bluegrass (OGBG) pastures; 3) determine mare serum prolactin, estradiol, and progesterone concentrations associated with ingesting each pasture type over time; and 4) measure foaling outcomes, including percentage of live foals, foal birth weights, and foal growth rates. In 2015, six nonpregnant mares grazed KY31, six pregnant mares grazed NE and six pregnant mares grazed OGBG pastures. In 2016, eighteen mares were used; six mares grazed each pasture type. Study results showed that ergovaline did not appear to be produced by NE. Novel endophyte pasture did not have negative effects on palmar artery diameter, reproductive hormones, or foaling outcomes.

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Lucero, Jacob Elias. „Cheatgrass (Bromus tectorum), Native Grasses, and Small Mammals in the Great Basin: a Test of the Apparent Competition Hypothesis Facilitated by a Novel Method of Decanting Seeds from a Flotation Solution“. BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3405.

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The effect of shared enemies between invasive and native species has been argued to facilitate biological invasions (i.e., the apparent competition hypothesis or ACH). This study investigated a previously untested possibility: whether granivorous small mammals facilitate cheatgrass (Bromus tectorum) invasion by driving food-mediated apparent competition between cheatgrass and native grasses. Specifically, we tested three predictions that must be true if such apparent competition occurs. First, cheatgrass invasion augments total seeds available to granivorous small mammals. Second, density of granivorous small mammals increases in response to increased seed availability (simulated with experimental additions of cheatgrass seeds). Third, granivorous small mammals prefer seeds from native grasses over cheatgrass seeds. We tested these predictions in the Great Basin Desert of Utah, USA. Cheatgrass invasion augmented total yearly seed production. Granivorous small mammals preferred native seeds over cheatgrass seeds. However, neither abundance, richness, nor diversity of granivorous small mammals increased in response to experimental additions of cheatgrass seed. We therefore conclude that granivorous small mammals did not drive food-mediated apparent competition during the study period. The lack of support for the ACH in this study may suggest that the role of small mammal-driven apparent competition is either unimportant in the Great Basin, or that the appropriate indirect interactions between small mammals, cheatgrass, and native grasses have yet to be evaluated. Testing the third prediction required the separation of seeds from the soil matrix. We employed a chemical flotation methodology to recover target seeds from soil, and developed a novel method of decanting target material from the flotation solution. We compared the utility of the novel method to that of a traditional decantation method. Specifically, we compared effectiveness (the proportion of seeds recovered from a known sample), rapidity (the time required to decant that sample), efficiency (the number of seeds decanted per second), and recovery bias (the effect of relative density on seed recovery) between methods. Our proposed method was more effective, more rapid, more efficient, and less biased than the traditional method. Therefore, any future work relying on flotation to analyze seed banks should clearly describe how samples are decanted and should consider the proposed method as a potential means of enhancing the efficiency of chemical flotation.

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Cobb, Joshua Nathaniel. „Studies on Transformation of Tomato(Solanum lycopersicum L.) and Arabidopsis thaliana using Chimerical constructs of varying Tospoviral Origin“. Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2519.pdf.

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Drew, Gary S. „Winter Habitat Selection by American Marten (Martes americana) in Newfoundland: Why Old Growth?“ DigitalCommons@USU, 1995. https://digitalcommons.usu.edu/etd/6518.

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Although the American marten (Martes americana) generally is recognized as an obligate late-seral species, the factors dictating this association are poorly understood. Martens were studied in Newfoundland, Yellowstone National Park, and in a captive setting. As expected, use of habitat types was not proportional to availability P < 0.001). Defoliated and late-seral conifer stands were used more than expected, while all other types indicated expected or less than expected use. Habitat selection by martens was detectable at spatial scales greater than 80 m (P < 0.001). Newfoundland martens were radio-collared and monitored for diet activity during the winters of 1990 and 1991. A regression of the percent active fixes on temperature had a negative slope (P = -4.45, P= 0.084, n = 12), indicating that martens did not minimize their exposure to low temperatures. A log-linear model suggested that the presence or absence of light was the only factor associated with marten activity patterns (P < 0.001). Martens in Western Newfoundland and a population in Yellowstone National Park were tested for their response to predation risk using bait stations in various habitat types. Visitation rates of martens at bait-boxes were not different between study sites (P = 0 .190). However, martens visitation by habitat was different (P = 0.001). Martens use of bait-boxes was similar in old-growth and defoliated habitats, suggesting that foliar cover may not have a strong influence on the risk of predation for martens during winter. Martens did use bait-boxes in defoliated stands to a greater extent than those in open habitats (P < 0.001), suggesting that they perceived stem structure as decreasing predation risk. In captive experiments, martens selected areas with both overhead cover and woody stem structure (P = 0.012). I detected no difference between the use of areas with only overhead cover and those having only stem structure (P = 0.671). However, martens decreased foraging activity in response to a predatory cue (P = 0.004). The inability of martens to use food resources in areas lacking cover during the summer suggests a perception of increased threat associated with these areas.

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Abdulle, Abdinasir M. „A Descriptive Study of Range Livestock Operations in the Somali Central Rangelands“. DigitalCommons@USU, 1990. https://digitalcommons.usu.edu/etd/6440.

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Information on livestock operations, particularly what kind of livestock operations are practiced in the Somali central rangelands, and how these operations differ for different herders in different vegetation types and farming systems, could serve as a major tool in making management decisions. This study provides a detailed description of range livestock operations in the Somali Central Rangelands. It also answers some important management questions. Range livestock operations were inventoried through personal interviews with the owners and herders. Data are supplemented by previous nation-wide and regional survey statistics. Herd productivity data which include herd structures, age, age-related sales, slaughters, gifts, and Zakat (religious payment) was derived from the herd recording survey. The results indicate the need for long term data to serve as a base for decisions concerning range and livestock development.

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Rabin, Daniel. „Using Computer Imaging to Assess Visual Impacts of Forest Insect and Disease Pests“. DigitalCommons@USU, 1989. https://digitalcommons.usu.edu/etd/6446.

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Forest insect and disease pests alter the appearance of trees, thereby impacting visual resources. Because of the complexity of most forest landscapes, the degree of visual impact of pest-infested forest stands is difficult to quantify. This paper describes a method of measuring visual impacts of pest-infested forest stands. Photographs of healthy Ponderosa pine trees were entered into a computer video-image-processing system. Using this system, images of trees were altered to simulate different degrees of infestation by limb rust, a forest pathogen. The altered and unaltered images were shown to groups of observers who rated the scenes in terms of "scenic beauty." The great majority of individuals were able to detect a change in the appearance of trees infected with limb rust disease even when only small sections of a tree were altered. There was also general agreement within the groups of observers that the presence of limb rust disease had a detrimental effect on the visual quality of the forest scenes. The tests also suggested that the location of infestation in the tree crown, the amount of crown mortality, and the number of infected Ponderosa pine in a stand influenced the degree to which visual quality was impacted.

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Sharp, Aaron Robert. „Improving Cotton Agronomics with Diverse Genomic Technologies“. BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5845.

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Agronomic outcomes are the product of a plant's genotype and its environment. Genomic technologies allow farmers and researchers new avenues to explore the genetic component of agriculture. These technologies can also enhance understanding of environmental effects. With a growing world population, a wide variety of tools will be necessary to increase the agronomic productivity. Here I use massively parallel, deep sequencing of RNA (RNA-Seq) to measure changes in cotton gene expression levels in response to a change in the plant's surroundings caused by conservation tillage. Conservation tillage is an environmentally friendly, agricultural practice characterized by little or no inversion of the soil prior to planting. In addition to changes in cotton gene expression and biological pathway activity, I assay the transcriptional activity of microbial symbiotes living in and around the cotton roots. I found a large degree of similarity between cotton individuals in different treatments. However, under conventional disk tillage I did find significantly greater activity of cotton phosphatase and sulfate transport genes, as well as greater abundance of the microbes Candidatus Burkholderia brachynathoides and Arthrobacter species L77. This study also includes the use of high-throughput physical mapping of DNA to examine the genomic structure of a wild cotton species, Gossypium raimondii, which is closely related to the economically significant crop species Gossypium hirsutum. This technology characterizes genomic regions by assembling large input DNA molecules labeled at restriction enzyme recognition sites. I created an efficient algorithm and generated 812 whole genome assemblies from two datasets. The best of these assemblies allowed us to detect 3,806 potential misassemblies in the current release of the G. raimondii genome sequence assembly.

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Cline, Nathan Lyle. „Wet-Thermal Time and Plant Available Water in the Seedbeds and Root Zones Across the Sagebrush Steppe Ecosystem of the Great Basin“. BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4384.

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Following wildfires, plant materials are direct-seeded to limit erosion and annual weed invasion. Seedlings often fail to establish because selected plant materials are not always well adapted to local soil moisture and temperature conditions. In an effort to help improve plant materials selection and to evaluate sites potential revegetation, we have worked toward developing methodology to predict germination and root growth based on site specific soil moisture and temperature conditions. First, we characterized the seedbed environment of 24 sagebrush (Artemisia spp.) steppe sites throughout the Intermountain West to determine the wet-thermal time of five temperature ranges relevant to germination response and thermal-time model accuracy (Chapter 1). Second, we predicted potential germination for 31 plant materials at those same sites (Chapter 2). Third, in preparation to predict root growth at multiple sites, we characterized the drying patterns and the associated plant-available water for in the seedling root zone across nine woodland (Juniperus spp. and Piñus spp.) sites (Chapter 3). For all of these studies, we determined the effects of tree reduction and tree infilling phase at time of tree reduction. Our key findings are that seedbeds generally sum most wet-thermal time at temperature ranges where the germination rates fit thermal accumulation models quite well (R2 ≥ 0.7). The majority of plant materials summed enough wet-thermal time for a potential germination at most sites during the fall, early spring, and late spring. Soil drying primarily occurs from the soil surface downward. Drying rates and Plant available water associated with the first drying event increased with increasing soil depth. Root zone (1-30 cm) plant-available water increased before and decreased after the first spring drying event with increasing soil depth. Tree removal with increasing pretreatment tree infilling phase generally added progress toward germination, plant available water, and wet-thermal time in the seedbed and root zones of the sagebrush steppe in the Great Basin. Because soil moisture and temperature does not appear to be limiting for potential germination, combining germination and root growth models to create a more comprehensive model may allow for a more robust prediction for seedling survival. For either root growth or combined germination and root growth models, plant available water and wet-thermal time before the first spring drying period hold the most potential for successfully predicting seedling survival.

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Laurent, Christine. „La "micro-archéologie": méthode et applications sur des sites de Wallonie et de la Région bruxelloise“. Doctoral thesis, Universite Libre de Bruxelles, 2001. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211696.

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Ehanno, Bernard. „Les Hétéroptères miridés de France (heteroptera-miridae) : distribution biogéographique et contribution à l'étude de leurs rapports avec les plantes et les milieux naturels“. Rennes 1, 1988. http://www.theses.fr/1988REN10019.

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L'importance de la taxinomie dans la réactualisation des données est mise en valeur. Le rôle prééminent de la plante hôte est souligné : elle offre aux insectes un abri pour l'hibernation des œufs et contribue leur support nutritionnel. L'accent est kis sur l'importance des végétaux pérennes ou à organes pérennants susceptibles d'accueillir le miridé et de conserver sa ponte. L'étude biogéographique intègre les données écologiques, elle propose une répartition de 490 miridés

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Vesterlund, Katja, und Alexandra Adamovic. „Proteiner : En kvantitativ studie om individers kunskap och val av proteiner“. Thesis, Luleå tekniska universitet, Institutionen för hälsovetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-74932.

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Vi påverkas av allt runt omkring oss vilket direkt eller indirekt styr våra beslut av matval. Tidigare studier indikerar vikten av en balanserad kosthållning med ett likvärdigt intag av animalisk och växtbaserad protein för en hälsofrämjande livshållning. Studiens syfte var att ta del av allmänhetens kunskap och val kring proteiner. En webbaserad enkätundersökning delades ut via sociala medier för ett bredare urval. Bland de 105 respondenterna fanns en överrepresentation inom åldrarna 18-32 år och majoriteten var högutbildade. De främsta skälen till deras val av proteiner var pris, smak och djurhållning. Trots hög andel med universitetsutbildning var kunskapsnivån bristande kring proteiner och dess ändamål. Slutsatsen av studien pekar på vikten av kontinuerlig och uppdaterad information för att rätt kunskap ska erhållas av individerna. Detta är något som hälsovägledare kan bidra med.
Humans are affected from their surrounding which may control our choices when it comes to food intake. Previous studies highlights the importance of a balanced nutrition which contains equal intake of animal and plant-based protein for the health outcome. The aim of this study is to find out people's knowledge and options of proteins. A web-based survey was sent out via social media in order to gain a wide ranging variety in participants. Amongst the participants, there was a preponderance amongst persons between the ages of 18-32 and people with higher education. The foremost reasons the respondents gave about their choices were costs (price), taste and animal agriculture. Although mainly were highly educated, the results of the study showed lack of knowledge about protein and its purpose. This leaves us to the conclusion that the profession as health promoters is needed to provide continuously and updated information to the public in order to maintain a state of good health.

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König, Malin A. E. „Context dependency of plant – animal interactions“. Doctoral thesis, Stockholms universitet, Institutionen för ekologi, miljö och botanik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-101067.

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The strength and direction of interactions between organisms vary spatially across the landscape. Traditionally, the focus has been on how trait variation affects the interactions between species. However, differences in abiotic and biotic environmental factors may also alter the distribution, phenology and behavior of the interacting species. To be able to understand why an interaction varies across the landscape, the effects of trait variation has to be separated from the effects of the environmental context. In this thesis, I try to separate the effects of context and trait differences on plant resistance against herbivory, through experimental and observational studies conducted with two cytotypes of the perennial herb Cardamine pratensis and its main herbivore, Anthocharis cardamines. The results show that differences in plant resistance against oviposition under controlled conditions were mainly mediated by flower size; larger flowers were more attractive to the female butterfly. However, among-populations differences in oviposition under natural conditions were not related to the resistance observed under controlled conditions, or to ploidy type, flowering phenology or plant size. Within populations under natural conditions the oviposition patterns by A. cardamines was affected by the plant traits plant size and flowering phenology. The result of this thesis shows that among-population differences in intensity of plant-herbivore interactions were caused by differences in environmental context rather than by herbivore preferences for any phenotypic plant traits, while host plant selection within population was based on plant traits. This suggests that biotic and biotic context can have important effects on the intensity of plant-herbivore interactions. Although genetic traits influenced the outcome of the interaction within populations, it was the environmental context of the populations that determined largely if the interaction took place or not.

At the time of the doctoral defence the following papers were unpublished and had a status as follows: Paper 2: Manuscript in review in Plos One; Paper 3: Manuscript in review in Ecological Entomology; Paper 4: Manuscript

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Middlebrooks, Michael Louis. „Consequences of Kleptoplasty on the Distribution, Ecology, and Behavior of the Sacoglossan Sea Slug, Elysia clarki“. Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4162.

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The sacoglossan sea slug Elysia clarki is able to photosynthesize for three to four months using chloroplasts sequestered from its algal food sources. Furthermore, the slug is able to store multiple chloroplasts from different algal species within the same cell. This research, consisting of several related studies, explores the role that provision of organic nutrients via photosynthesis plays in the biology of the slug. The first chapter demonstrates that, under conditions of starvation, photosynthetic activity in E. clarki remains fully functional for one month after which it then declines. During the first month of starvation the slug exhibits similar feeding behavior as slugs provided a continuous supply of food, suggesting that photosynthesis delays the onset of starvation-induced behavioral changes. The second chapter explores E. clarki's spatial relationships with algae known to be food sources in the field. In areas with high slug density, edible algal populations were very low. DNA barcoding was employed to demonstrate that the algae found near slugs were poor predictors of which foods were actually consumed by slugs. Generally, there was a mismatch between algae available in the field and slug diets. The third chapter explores how E. clarki is able to maintain photosynthesis. After labeling with a C14 ALA incubation process, then chlorophyll was extracted from slugs and purified using HPLC. Results indicate that recently collected E. clarki are able to synthesize chlorophyll, whereas slugs starved for 3 months were not. Photosynthesis plays a very important role for E. clarki and its relationships with food algae.

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Granados, Alys. „Ecological effects of disrupting plant-animal interactions“. Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62963.

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Human disturbances threaten tropical forests, potentially disrupting plant-animal interactions. Though many studies have assessed the effects of habitat disturbance on either plants or animals, we have a limited understanding of how disrupted interactions will affect both groups of interacting species and whether impacts vary with spatial scale. This hinders our ability to predict how logging, a widespread threat to tropical forests, affects plant and animal communities, particularly in combination with overhunting, a common co-occurring threat. I excluded small to large-bodied mammals from research plots in logged and unlogged forests in Borneo to quantify the effects of logging and hunting on seed predation and establishment in five dominant tree species (Chapter 2). Granivore-induced seed mortality was higher in logged forest. Defaunation did not affect seed mortality. Seedling establishment was highest when small to large-bodied mammals were excluded in logged forest, suggesting that the effects of logging and hunting interact to alter seedling recruitment. I used the same animal exclusion plots to assess impacts on diversity and the distribution of morphological traits in tagged seedling communities over four years (Chapter 3). Excluding small to large vertebrates did not affect overall seedling diversity but animals disproportionately killed seedlings from large-fruited genera in logged forest, reducing community fruit size. Animals altered plant traits, though impacts may be underestimated by focusing only on changes to taxonomic diversity. Selective logging can also intensify the patchiness of food availability across the landscape. Spatiotemporal variability in food abundance is especially pronounced during mast fruiting events, yet the consequences for animal habitat use at different spatial scales in faunally intact systems is unclear. I used camera traps to estimate the site use of several vertebrate species across two dipterocarp mast years and a non-mast year at large and small spatial scales (Chapter 4). Site use was positively associated with masting for several taxa, though strong response were mostly limited to intact forest. Even key consumers (bearded pigs) showed reduced responses in the logged forest at the small scale. Overall, my work demonstrates that anthropogenic disturbances disrupt plant-animal interactions by altering plant recruitment and limiting vertebrate responses to resource availability.
Science, Faculty of
Zoology, Department of
Graduate

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Zemp, Franz Joseph, und University of Lethbridge Faculty of Arts and Science. „The bystander effect : animal and plant models“. Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2008, 2008. http://hdl.handle.net/10133/685.

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Bystander effects are traditionally known as a phenomenon whereby unexposed cells exhibit the molecular symptoms of stress exposure when adjacent or nearby cells are traversed by ionizing radiation. However, the realm of bystander effects can be expanded to include any systemic changes to cellular homeostasis in response to a number of biotic or abiotic stresses, in any molecular system. This thesis encompasses three independent experiments looking at bystander and bystander-like responses in both plant and animal models. In plants, an investigation into the regulation of small RNAs has given us some insights into the regulation of the plant hormone auxin in both stress-treated and systemic (bystander) leaves. Another plant model shows that a bystander-like plant-plant signal can be induced upon ionizing radiation to increase the genome instability of neighbouring unexposed (bystander) plants. In animals, it is shown that the microRNAome is largely affected in the bystander cells in a three-dimensional human tissue model. In silico and bioinfomatic analysis of this data provide us with clues as to the nature of bystander signalling in this human ‘in vivo’ model.
xiv, 141 p. : ill. ; 29 cm.

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Kolehmainen, William John. „Effect of Plane of Nitrogen Nutrition and Somatotropin on Milk Production and Composition of Holstein Cows in Early Lactation“. The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1419349047.

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Jana, Prado Rocio Cecilia. „Animal seed dispersal and its consequences for plant recruitment“. Thesis, University of Canterbury. Biological Sciences, 2012. http://hdl.handle.net/10092/7366.

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Seed dispersal in New Zealand relies on a different guild from the one present before the arrival of humans into the islands. Post-dispersal biotic and abiotic filters have also changed due to the introduction of seed predators and herbivores. The aim of this thesis was to evaluate the actual contribution of seed dispersers to the patterns of seed fall and to understand the effects of biotic (seed density, predators, distance from conspecifics) and abiotic (pH, canopy openess, etc) factors on seed and seedling survival. I expected that tree species with different fruit sizes would be selected by different assemblages of dispersers, therefore being deposited and recruiting differentially on the forest floor. I analyzed the changes in small-scale seed diversity with the use of seed traps during two seasons in two 0.36 ha plots in a mixed broadleaf-podocarp temperate forest. The diversity of seeds was lower for in-fruit seeds (1.40 species per grid-cell) than for bird-dispersed seeds (2.62). The dominant species D. cupressinum was dispersed towards con- and heterospecific canopies (wind-dispersed trees Weinmannia racemosa and Metrosideros umbellata), giving a probable mechanism for the observed increase in finescale seed diversity. Then, using a 12-year dataset on seed fall I analyzed the changes in ground-level seed heterogeneity generated by bird-dispersed seed rain (propagule-scale) relative to the canopy composition (adult-scale) on six tree species. A Non Metric Multidimensional Scaling analysis demonstrated that the differences in species composition between sampling points (seed traps) were larger for tree canopies than for dispersed seeds. Different tree species acted as seed importers and/or exporters, although these patterns were not explained by fruit size or the richness of the disperser assemblages. I also investigated the effects of seed and seedling density on seed predation, seedling emergence and seedling survival to 12 months of five tree species. Seed predation increased with seed size, and it was higher at high density only for the largest-seeded species Beilschmiedia tawa and Prumnopitys ferruginea. Access of seed and seedling predators to the propagules was the main factor affecting seedling emergence and seedling survival. Abiotic variables were important for germination and seedling survival of the two small-seeded species, but only biotic predictors (mammalian exclosure and density) were important for medium and large-seeded species. Finally, using a split-plot experimental design I measured the effects of (a) the presence of conspecific canopy, (b) high conspecific seed densities and (c) introduced (or invasive) mammal access on seedling emergence and seedling survival (Janzen-Connell effects). Distance effects were stronger than density effects, and mediated by native and exotic predators. Final survival under conspecifics was strongly reduced in both species, with zero survival of B. tawa under conspecifics, and near zero (2/896) under D. dacrydioides. Seed dispersal service in New Zealand is still enough to produce changes in the spatial pattern of seed deposition in the forest. Post-dispersal processes such as seed predation and herbivore are having strong impacts on the survival and potential recruitment of plant species. Large-seeded trees are the most affected in terms of the impact of introduced mammals on seed predation, but seedling survival is affected independent of seed size. However, it is unknown how different these ecological processes are from the original situation without pests in New Zealand. The results of my research can contribute with valuable information for future research trying to understand the consequences of seed dispersal for recruitment, as well as inform complex models that try to predict the long-term impacts of the exotic mammals introduced in New Zealand.

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48

Parker, John Daniel. „Does Plant Diversity Control Animal Diversity?: An Experimental Approach“. W&M ScholarWorks, 1998. https://scholarworks.wm.edu/etd/1539617738.

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Gormley, Richard. „Animal population estimation using mark-recapture and plant-capture“. Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3655.

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Mark-recapture is a method of population estimation that involves capturing a number of animals from a population of unknown size on several occasions, and marking those animals that are caught each time. By observing the number of marked animals that are subsequently seen, estimates of the total population size can be made. There are various subclasses of the mark-recapture method called the Otis-class of models (Otis, Burnham, White & Anderson 1978). These relate to the assumed behaviour of the individuals in the target population. More recent work has generalised the theory of mark-recapture to the so-called plant-capture, where a known number of animals are pre-inserted into the target population. Sampling is then carried out as normal, but with additional information coming from knowledge of the number of planted individuals. The theory underpinning plant-capture is less well-developed than mark-recapture, with the difference on population estimation of the former over the latter not often tested. This thesis shows that, under fixed and random sample-size models, the inclusion of plants can improve the mean point population estimation of various estimators. The estimator of Pathak (1964) is generalised to allow for the inclusion of plants into the target population. The results show that mean estimates from most estimators, under most models, can be improved with the inclusion of plants, and the sample standard deviations of the simulations can be reduced. This improvement in mean point population estimation is particularly pronounced when the number of animals captured is low. Sample coverage, which is the proportion of distinct animals caught during sampling, is also often sought by practitioners. Given here is a generalisation of the inverse population estimator of Pathak (1964) to plant-capture and a proposed new inverse population estimator, which can be used as estimates of the coverage of a sample.

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50

Stemerding, Dirk. „Plants, animals and formulae natural history in the light of Latour's Science in action and Foucault's The order of Things /“. Enschede : Maastricht : Faculteit Wijsbegeerte en Maatschappijwetenschappen, Universiteit Twente ; University Library, Maastricht University [Host], 1991. http://arno.unimaas.nl/show.cgi?fid=5638.

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Dissertationen zum Thema „Plant and animal science“

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