Life Sciences Commons^™

Relative Productivity And Persistense Of White Clover Cultivars Under Cutting Or Continuous Stocking By Sheep, D A. Davies, M Fothergill

IGC Proceedings (1977-2023)

Perennial ryegrass-white clover (Lolium perenne-Trlfollium repens) swards of 3 clover cultivars were studied at a lowland (30 m) and upland (340 m) site in mid Wales over 3 years (1989-91). Lamb production from small-leaved Aberystwyth S 184 at 1021 kg/ha was 25% and 1191, more than from small-leaved Ac3351 and medium-leaved Grasslands Huia respectively. The relative lamb output from Huia was poorer at the upland location. Clover production, survival and morphology under a number of cutting heights and frequencies were different from those in the continuously stocked pastures. Cutting every 10 days at 2-3 cm resulted in poor clover and …

Morphological Changes In Three Clover (Trifolium Repens L.) Cultivars Under Continuous Stocking, M Fothergill, D A. Davies

IGC Proceedings (1977-2023)

Individual plant morphology of 3 white clover (Trifolium repens L.) cultivars was studied during 1990 and 1991. Seasonal shifts were demonstrated by all cultivars towards a higher proportion of less complex plants from winter to mid summer. Over the latter half of the year the population tended lo return towards its original distribution. Seasonal fluctuations in stolon dry weight/plant and root number/plant were also identified, with the small-leaved Ac3351 maintaining a greater stolon OW/plant than Aberystwyth S184 and Grasslands Huia during 1990. Ac3351 and S184 also maintained a larger root number/plant over this period. However, no significant differences were detected …

Response To Defoliation Of Tall Fescue, H Tavakoli, J Hodgson, P D. Kemp

IGC Proceedings (1977-2023)

An experiment studying the behaviour of toll fescue (Fesutca anrundinacea Schreb,) was conducted under steady stale grazing on a sward dominated by this plant. The swards were grazed lo maintain a surface height of 30-40 mm (H), 50-60 mm (M) and 90-100 mm (L). These treatments were applied on swards with and without white clover (Trifolium repens L.) from November 1990 to April 1991. Results showed that leaf growth decreased as the severity of grazing increased. Tiller number was less under H grazing than under M or L grazing, but tiller size remained constant over time in this …

Carbon Isotope Discrimination And Productivity Of Yellow-Flowered Falcata Alfalfa Clonesj, J A. Morgan, D R. Lecain, C E. Townsend

IGC Proceedings (1977-2023)

Although genetic variation for water•use efficiency has been identified in a number of plant species, progress to genetically increase this trait has been limited, largely owing to the difficulty in evaluating numerous genotypes. Eleven clones of yellow-flowered, falcata-type alfalfa (Medicago saliva L. ssp. falcata (L.) Arcangeli} were grown in the greenhouse under 2 watering regimes, and in space•planted field plots for 2 years. Clonal variation was found in all 4 environments for plant yield and shoot carbon isotope discrimination (A), a trait believed to estimate plant water use efficiency. Generally non­significant correlations between A and forage yield suggest that …

Adaptation Of Sainfoin Cultivars And Lucerne To Water Stress, S R. Mir Hosseini, P D. Kemp, D J. Barker, J Hodgson

IGC Proceedings (1977-2023)

Sainfoin ( Onobrychis viciifolia Scop.) is of particular interest as a pasture crop because it is a productive legume in dry areas but does not induce bloat in ruminant animals. In this study 3·sainfoin cultivars (Fakir, Melrose and 035) and l lucerne (Medicago saliva L.) cultivar Grasslands Oranga were compared during a drying phase when water was withheld once; flowering began. A randomised complete block design with 4 replicates' was used. Transpiration rate (Tr) declined as volumetric soil water content (VSWC) was reduced. Stomata! resistance (Rs) increased and relative ivater content (RWC) decreased when VSWC decreased. Critical VSWC for …

Phytochrome Control Of Assimilate Partitioning In White Clover, Ch Robin, C Varlet-Grancher, F Gastal, A Guckert

IGC Proceedings (1977-2023)

Experiments were conducted in controlled conditions to examine the influences of phytochrome on assimilate partitioning between stolons and branches and to determine the effects on plant moq>hogcncsis in white clover (Trifolium repens L.). Far-red (FR) irradiated plants partitioned more 14C-assimilates to petioles of both the main stolon and branches and less to the nodulated COOis than did control plants. Results clearly demonstrated that FR-irradiated plants developed longer petioles and long internodes. Moreover, the branching rate decreased, which induced a lower portion of dry weight allocated to branches. However, the sink strength of the branches which were developing remained …

Influence Of Rooting On Stolon Branching In White Clover, M Jones, N R. Sackville Hamilton

IGC Proceedings (1977-2023)

The relationship between rooting and branching in stolons of white clover (Trifolium repens L.) was investigated in a field experiment, Half of a group of stolons was allowed to develop roots naturally, while for the other half root establishment was prevented by severing young roots before they made contact with the soil. Prevention of root establishment did not affect the numbers of branches which developed on nodes produced during the experiment, and it stimulated of branching on nodes which were already present. This result was unexpected on the basis of earlier observations of stolon growth and suggests that the …

Accumulation Of Dry Matter, Protein And Total Available Carbohydrate In Berseem Under Different Cutting Regimes, P Martinello, G De Santis, A Iannucci, N Di Fonzo

IGC Proceedings (1977-2023)

The effect of different cutting regimes on physiology and morphology of aerial parts and roots in 6 bcrseem (Trifolium alexadrium L.) genotypes was evaluated. Observations were carried out on individual plants at 4 stages of development: fourth and eighth internode elongation, early flowering and physiological seed maturity. The results showed that the genotypes were characterised by highest values of dry matter in the aerial and root parts at the early flowering stage. Variability among genotypes was observed.

Seasonal Growth Rhythms In Lucerne, C Poisson, G Genier, A Canal, P Guy, A Porcheron

IGC Proceedings (1977-2023)

The repartition of dry matter production of lilcerne (Medicago saliva) through the year is of great interest. A 3-year experiment began in 1990 to distinguish different rhythms of regrowth. Eighteen genotypes of very diverse geographic origins exhibiting great differences of winter dormancy were studied in a multisite experiment. Two different non-destructive methods were used to describe accurately leaf area index evolution: red far/red light ratio (660 nm/730 nm), and indirect measurement of LAI {LI-COR 2000); stem height and dry matter yield were regularly recorded. Important differences in summer and autumn behaviour leading to different sigmoid growth curves wece …

Inherent And Realized Potential Of Axillary Buds Of White Clover In Field Populations, P.C D. Newton, M.J M. Hay

IGC Proceedings (1977-2023)

Fewer than 10% of while clover (Trifolium repens L.) axillary buds form established branches in grazed swards. In order to understand the mechanisms controlling his large loss of growth potential we have charted the potential fates a bud may meet. Each step in this flow chart offers the possibility for a loss of branching potential. We consider the factors that may be important in determining the fates of buds and highlight in particular the heavy losses of viable buds at a young age and propose that different factors may control branch initiation and branch establishment.

Prediction Of Plant Mortality Under Grazing- A Conceptual Approach, J J. Mott, G K. Mckeon, K A. Day

IGC Proceedings (1977-2023)

Based on the concept of biological thresholds, there is growing acceptance 0£ the importance o£ episodic events in the determination of rangeland condition trend. The variable rainfall occurring within Australian rangelands means that overstocking during droughts is a major cause of these Australian rangeland vegetation complexes exceeding these thresholds. Recently plant production models and simplistic estimates of the relationship between animal utilisation and plant mortality became available. Accurate estimates will be developed only with the incorporation of a sound mechanistic understanding of the relationship between utilisation of forage and plant mortality for different conditions of species and soils. Detailed studies …

Canopy Structure And Forage Production Of Lolium Rididum Gaudin As Influenced By The Frequency Of Defoliation, P P. Roggero, A Franca, M Sitzia, S Caredda

IGC Proceedings (1977-2023)

An experiment was conducted in Sardinia to develop an appropriate rotational grazing management regime in spring for an ecotype of annual ryegrass (Lolium rigidum Gaudin). Three intermittent defoliation treatments were compared using sward surface height (10, 15 or 20 cm) to determine time of cutting. Forage dry matter yield, tiller population density, LAI, vertical distribution of plant tissues and other related characteristics were measured. Cutting when sward reached 10 cm resulted In significantly lower yields but a better canopy structure (denser sward, higher percentage of leaves in the bottom layers, higher leaf: sheath ratio) than the other treatments. The …

Physiological Response And Leaf Production Of Two C4 Grasses After Small Rainfall Events, A J. Norman, T L. Thurow, C A. Taylor Jr

IGC Proceedings (1977-2023)

The response of plant water status and leaf production of sideoats grama (Bouteloua curtipendula Michx.) and curly mesquite (Hilaria belangeri Steud.) to application of 10 mm of water were studied in 6 continuous weighing lysimeters near Sonora, Texas, USA.: Transpiration, stomata! conductance, xylem water potentials and leaf production were measured foe both species. Soil water content was monitored in each lysimeter. The 10-mm simulated rainfall events improved plant water status regardless of prior soil water· content.' The transpiration rate for both species was similar. Stomata! conductance' of B. c1irtipe11d11/a responded faster after the simulated rainfall events. More favorable …

Effects Of Cutting Dates In Primary Growth, Water Soluble Carbohydrate Content And Nitrogen Fertilization On Regrowth Of Perennial Ryegrass, W Pohlmann, U Simon

IGC Proceedings (1977-2023)

In a field experiment, an early• and a late-maturing cultivar of perennial ryegrass were cut during the primary growth in 6-weekly intervals starting when the early cultivar (Lolium perenne L.) reached stage of growth 31 (Simon & Park 1983, Proceedings XIV IGC), at 2 levels of nitrogen fertilisation. Dry mailer yield (DMY) in the regrowth was determined 4 weeks after defoliation in the primary growth. DMY in the regrowth decreased with delayed cutting in the primary growth. No significant correlation existed between the content of water soluble carbohydrates (WSC) in 1he stubble at the time of defoliation in the …

Effect Of Row Spacing And Sowing Rate On Establishment Of Lucerne Cv. Grasslands Oranga, M Askarian, J G. Hampton

IGC Proceedings (1977-2023)

Studies on the effects of various row spacings and sowing rates on the establishment of autumn-sown lucerne (Medicago saliva L) cv. Grasslands Oranga were carried out in a split-plot experiment at Massey University Palmerston North, New Zealand. Seed was sown on 15 March 1991 at 1, 3, 6 and 12 kwha at row spacings of 15, 30, 45 and 60 cm. Seedling establishment increased as sowing rate and row spacing increased, but numbers of seedlings were not directly proportional to the number of seeds sown. The percentage establishment 6 months after sowing was significantly higher atthe lowest sowing rate. …

Enhancing Sustainable Cultivation Of Organic Bell Pepper Through Fulvic Acid (Fa) Application: Impact On Phytochemicals And Antioxidant Capacity Under Open-Field Conditions, Pinkky Kanabar, Ying Wu, Dilip Nandwani

Agricultural and Environmental Sciences Faculty Research

Fulvic acid (FA) is an eco-friendly solution for reducing the reliance on agrochemicals and enhancing crop quality. The study aimed to investigate the impact of soil and foliar application of FA on the phytochemical content and antioxidant properties of organically grown bell peppers at both the green and red stages. Bell pepper cv. Revolution was grown under open-field conditions at the certified organic farm at Tennessee State University, Nashville, with nine treatments and three replications. FA was applied as a soil drench and foliar spray at four different rates (0, 2.3, 5.5, 7.8, 10.9 mL L−1). The fruits were harvested …

Conservation Decision Making And Agricultural Land Leasing - An Experimental Investigation Of The Role Of Gender, Diya Ganguly, Simanti Banerjee, Christopher Gustafson

Cornhusker Economics

This research investigated the impact of landowner gender and of the different types of contract leases offered by them to a male tenant, on the conservation (or non-conservation) choice made by the tenant. Specifically, we investigate if a) female and male landowners offer different rental contracts and b) whether tenants choose different actions based on the landowner’s gender. For this purpose, we implemented a controlled, gender-context-loaded economic experiment with university students, in which we tested contract and land use choice under different treatments for three types of rental contracts – fixed rent, fixed rent with penalty, and fixed rent with …

The Effects Of Simulated Predation And Nursery Structure On Post-Outplant Survival And Growth Of Sexual Juveniles Of Six Caribbean Coral Species, Jarrod Little

All HCAS Student Capstones, Theses, and Dissertations

Over the past few decades, increasing frequency and severity of direct and indirect anthropogenic stressors have resulted in reef degradation and decreased coral cover and diversity. In South Florida, coral propagation ex situ has gained popularity as a means to restore coral cover. Outplanting sexually propagated corals on the reef is particularly important as it contributes to greater genetic diversity and potentially overall reef resilience. However, these corals typically experience high levels of predation following outplanting, significantly reducing coral survival, and thus constitute a major bottleneck to the success of restoration efforts. This study assessed if simulated predation events on …

Laying Framework For A Novel In Vitro Eukaryotic System To Measure Rate Of Transcription Elongation, John Lucas Ramirez

Theses and Dissertations

Within each cell, genetic material is stored in the form of DNA. This DNA is compacted around proteins to form higher order structures called chromatin. The basic unit of chromatin is a histone protein octamer bound with DNA called a nucleosome. A nucleosome consists of eight core proteins, four pairs of histone proteins H2A, H2B, H3, and H4, wrapped by DNA. The DNA wraps around the histone protein roughly 1.7 times, helping facilitate the compaction of DNA within the nucleus of the cell. The location of nucleosomes makes genetic material that encodes various elements, such as promoters or enhancers, accessible …

Connecting Hiv-1 Viral Protein R Polymorphisms To Changes In Inflammatory Signals And Efficacy Testing Of Essential Oils As Disinfectants Against Sars-Cov-2, J. Brandon Lopez

Theses and Dissertations

Human Immunodeficiency Virus (HIV-1) is the causative agent for acquired immunodeficiency syndrome (AIDS). Different strains of HIV-1 have been linked to a long term non-progressor (LTNP) or rapid progressor (RP) form of disease depending on rate of AIDS progression. Viral protein R (Vpr) is a viral protein that has been linked to varying rates of AIDS progression depending on the sequence. In this work, the effects of two polymorphisms, a LTNP and a RP, on different cells are studied. The LTNP virus was linked to lower release of pro-inflammatory cytokines, such as TNF and IL-6, and an increase in apoptotic …

Molecular Mechanisms Behind Methionine-Derived Glucosinolate Diversity In Brassica Plants, Vivian Kitainda

Arts & Sciences Graduate Student Theses and Dissertations

In Brassica plants, glucosinolates are a diverse class of natural products that serve as plant defense molecules. Their structural diversity comes from the use of amino acids as precursors and elongation of side chains by up to nine carbons, as well as further chemical modifications. Aliphatic methionine-derived glucosinolates are the most abundant form of these compounds. Although both elongation and chemical modification of amino acid sidechains are important for methionine-glucosinolate diversity, its elongation process has not been well described. The chain elongation enzyme methylthioalkylmalate synthase (MAMS) functions as the glucosinolate pathway gatekeeper through its substrate specificity. The x-ray crystal structure …

Developing Computational And Experimental Tools For Investigating Intrinsically Disordered Proteins And Biomolecular Condensates, Daniel Griffith

Arts & Sciences Graduate Student Theses and Dissertations

Intrinsically disordered proteins and protein regions (IDPs) compose a significant portion of eukaryotic proteomes yet remain relatively understudied. Unlike folded domains, IDPs lack a single fixed three-dimensional structure and instead are defined by a dynamic conformational ensemble. Despite this structural heterogeneity, IDPs carry out vital roles within the cell. IDPs are particularly important in cellular signaling and regulation, owing to their ability to mediate molecular interactions with a variety of affinities and specificities. Additionally, some IDPs drive the formation of higher-order non-stoichiometric assemblies called biomolecular condensates. This dissertation focuses on the development of a variety of computational and experimental tools …

Cellular And Molecular Basis Of Cd4+ T Cell Help At The Effector Phase During Immunotherapy Of Mhc-Ii Negative Tumors, Samuel Oche Ameh

Arts & Sciences Graduate Student Theses and Dissertations

Immune checkpoint therapies (ICT) have shown promise in treating solid tumors, providing cures and durable protection in some cases. However, only a subset of patients benefits from ICT, indicating a need for a deeper understanding of the requirements for successful therapy. In both mice and humans, αβ T cells are key mediators of spontaneous and ICT-induced anti-tumor responses. While the anti-tumor roles of CD8+ T cells are well-studied, the role of CD4+ T cells, particularly in ICT for MHC-II negative tumors, is less understood. New insights into how CD4+ T cells modulate CD8+ T cells during ICT may lead to …

Stem-Loop And Circle-Loop Tads Generated By Directional Pairing Of Boundary Elements Have Distinct Physical And Regulatory Properties, Wenfan Ke, Miki Fujioka, Paul Schedl, James Jaynes

Department of Biochemistry and Molecular Biology Faculty Papers

The chromosomes in multicellular eukaryotes are organized into a series of topologically independent loops called TADs. In flies, TADs are formed by physical interactions between neighboring boundaries. Fly boundaries exhibit distinct partner preferences, and pairing interactions between boundaries are typically orientation-dependent. Pairing can be head-to-tail or head-to-head. The former generates a stem-loop TAD, while the latter gives a circle-loop TAD. The TAD that encompasses the Drosophila even skipped (eve) gene is formed by the head-to-tail pairing of the nhomie and homie boundaries. To explore the relationship between loop topology and the physical and regulatory landscape, we flanked the nhomie boundary …

Video And Phone Visit Use Differed By Language Preference Among Us Latino And Chinese Adults During The First 9 Months Of The Covid-19 Pandemic: A Cross-Sectional Electronic Health Record Study, Nancy P Gordon, Teresa Y Lin, Antonia Torreblanca, Mary E Reed

Faculty, Staff and Student Publications

BACKGROUND: During the first nine months of the COVID-19 emergency, patients were encouraged to use virtual versus clinic visits if in-person care was not deemed necessary by clinical staff. This study examined the association of spoken language preference and ethnicity with use of video versus phone virtual visits by US Latino and Chinese adult patients who got care in the same healthcare system.

METHODS: We analyzed electronic health record data for four groups of adults aged 26-85y who had ≥ 1 primary or specialty care outpatient clinician visits during April-December 2020: 80,869 Latino adults preferring Spanish (LEP Latino); 214,765 Latino …

Modern Building Structures Are A Landscape-Level Driver Of Bat–Human Exposure Risk In Kenya, Tamika Lunn, Reilly T. Jackson, Paul W. Webala, Joseph G. Ogola, Kristian M. Forbes

Biological Sciences Faculty Publications and Presentations

Identifying the locations and drivers of high-risk interfaces between humans and wildlife is crucial for managing zoonotic disease risk. We suggest that continent-wide improvements to residential housing in Africa are inadvertently creating artificial roosting habitat for synanthropic free-tailed bats (family Molossidae), and that improved buildings are a rapidly accelerating exposure interface that needs urgent research attention and investment. Along a residential gradient in rural southern Kenya, we mapped building use by free-tailed bats in 1109 buildings. We show that bats often roost in human-occupied buildings, with almost one-in-ten buildings exhibiting evidence of bat occupation (9.2%) and one-in-13 found to contain …

Towards Building A Reliable Human-Machine Partnership: A Visual Analytics Approach, Sunwoo Jennifer Ha

McKelvey School of Engineering Graduate Student Theses & Dissertations

In recent years, the rapid advancement of artificial intelligence (AI) technology has sparked what has been coined by mass media as a global AI race. At the heart of this race lies the increasing integration of AI technology into our daily lives as well as in analytical workflows and high-risk decision-making processes. In visual analytics, the goal is to unify the strengths of both the human and the machine through an interactive visual interface to solve complex and overwhelming tasks together. To formulate a fruitful collaboration, researchers in the visual analytics community have proposed various intelligent methods to better understand …

Cefiderocol Heteroresistance Associated With Mutations In Tonb-Dependent Receptor Genes In Pseudomonas Aeruginosa Of Clinical Origin, Stephanie L Egge, Samie A Rizvi, Shelby R Simar, Manuel Alcalde, Jose R W Martinez, Blake M Hanson, An Q Dinh, Rodrigo P Baptista, Truc T Tran, Samuel A Shelburne, Jose M Munita, Cesar A Arias, Morgan Hakki, William R Miller

Faculty, Staff and Student Publications

The siderophore-cephalosporin cefiderocol (FDC) presents a promising treatment option for carbapenem-resistant (CR) P. aeruginosa (PA). FDC circumvents traditional porin and efflux-mediated resistance by utilizing TonB-dependent receptors (TBDRs) to access the periplasmic space. Emerging FDC resistance has been associated with loss of function mutations within TBDR genes or the regulatory genes controlling TBDR expression. Further, difficulties with antimicrobial susceptibility testing (AST) and unexpected negative clinical treatment outcomes have prompted concerns for heteroresistance, where a single lineage isolate contains resistant subpopulations not detectable by standard AST. This study aimed to evaluate the prevalence of TBDR mutations among clinical isolates of P. aeruginosa …

Discovering And Characterizing Conserved Anthelmintic Targets In The Early Parasitic Stages Of Gastrointestinal Nematodes, Hyeim Jung

Arts & Sciences Graduate Student Theses and Dissertations

Gastrointestinal nematodes (GINs) collectively infect 1.5 billion people, leading to mortality and various forms of morbidity in humans and hindering normal development in children. GINs also diminish the productivity of food animals, which are crucial for economic and nutritional well-being, particularly in developing countries. Currently, the world still primarily relies on only a few drug classes for global de-worming of GINs in humans and animals. However, the high rate of reinfection, disappointing treatment success rates, and increasing drug resistance make GINs one of the most important contributors to promoting and maintaining global poverty. This highlights the urgent need for more …

Seroprevalence And Associated Risk Factors Of Toxoplasma Gondii Infections In Dogs In Egypt, Abdelfattah Selim, Mohamed Marzok, Hattan S. Gattan, Omar A. Aljabr, Mohammed H. Alruhaili, Mohamed Salem

The Thai Journal of Veterinary Medicine

Toxoplasma gondii is a parasite that is found all over the world and has significant importance in veterinary medicine and public health. Dogs are considered as a final host for the parasite and play an important role in spreading of infection via contamination of environment by oocysts. The study aimed to determine the seroprevalence of T. gondii and analysis risk factors associated with the infections in dogs. A total of 430 blood samples were collected from dogs from three governorates situated at northern Egypt and analyzed using commercial ELISA kit. The overall seroprevalence of T. gondii in dogs was 24% …