93 research outputs found

    University of Nebraska-Lincoln Agricultural Research Division 121st Annual Report. July 1, 2006 to June 30, 2007.

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    Our Mission..... 4 Foreword..... 5 Research Highlights..... 6 Faculty Awards and Recognitions....14 Graduate Student Awards and Recognitions...17 Undergraduate Honors Student Research Program...22 Variety and Germplasm Releases....23 Patents.....24 Administration.....25 Administrative Personnel....25 Organizational Chart....26 Administrative Units....27 IANR Research Facilities....28 Faculty.....29 Agricultural/Natural Resources Units....30 Education and Human Sciences Departments...39 Off-Campus Research Centers....40 Interdisciplinary Activities....41 Visiting Scientists/Research Associates....42 Research Projects.....47 Agricultural/Natural Resources Units....47 Education and Human Sciences Departments...52 Off-Campus Research Centers....52 Interdisciplinary Activities....53 Publications.....55 Agricultural/Natural Resources Units....60 Education and Human Sciences Departments...82 Off-Campus Research Centers....85 Research Expenditures....8

    Stable Isotopes in Tree Rings

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    This Open Access volume highlights how tree ring stable isotopes have been used to address a range of environmental issues from paleoclimatology to forest management, and anthropogenic impacts on forest growth. It will further evaluate weaknesses and strengths of isotope applications in tree rings. In contrast to older tree ring studies, which predominantly applied a pure statistical approach this book will focus on physiological mechanisms that influence isotopic signals and reflect environmental impacts. Focusing on connections between physiological responses and drivers of isotope variation will also clarify why environmental impacts are not linearly reflected in isotope ratios and tree ring widths. This volume will be of interest to any researcher and educator who uses tree rings (and other organic matter proxies) to reconstruct paleoclimate as well as to understand contemporary functional processes and anthropogenic influences on native ecosystems. The use of stable isotopes in biogeochemical studies has expanded greatly in recent years, making this volume a valuable resource to a growing and vibrant community of researchers

    Handbook of Marine Model Organisms in Experimental Biology

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    "The importance of molecular approaches for comparative biology and the rapid development of new molecular tools is unprecedented. The extraordinary molecular progress belies the need for understanding the development and basic biology of whole organisms. Vigorous international efforts to train the next-generation of experimental biologists must combine both levels – next generation molecular approaches and traditional organismal biology. This book provides cutting-edge chapters regarding the growing list of marine model organisms. Access to and practical advice on these model organisms have become aconditio sine qua non for a modern education of advanced undergraduate students, graduate students and postdocs working on marine model systems. Model organisms are not only tools they are also bridges between fields – from behavior, development and physiology to functional genomics. Key Features Offers deep insights into cutting-edge model system science Provides in-depth overviews of all prominent marine model organisms Illustrates challenging experimental approaches to model system research Serves as a reference book also for next-generation functional genomics applications Fills an urgent need for students Related Titles Jarret, R. L. & K. McCluskey, eds. The Biological Resources of Model Organisms (ISBN 978-1-1382-9461-5) Kim, S.-K. Healthcare Using Marine Organisms (ISBN 978-1-1382-9538-4) Mudher, A. & T. Newman, eds. Drosophila: A Toolbox for the Study of Neurodegenerative Disease (ISBN 978-0-4154-1185-1) Green, S. L. The Laboratory Xenopus sp. (ISBN 978-1-4200-9109-0)

    Algae

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    Algae - Organisms for Imminent Biotechnology will be useful source of information on basic and applied aspects of algae for post graduate students, researchers, scientists, agriculturists, and decision makers. The book comprises a total of 12 chapters covering various aspects of algae particularly on microalgal biotechnology, bloom dynamics, photobioreactor design and operation of microalgal mass cultivation, algae used as indicator of water quality, microalgal biosensors for ecological monitoring in aquatic environment, carbon capture and storage by microalgae to enhancing CO2 removal, synthesis and biotechnological potentials of algal nanoparticles, biofilms, silica-based nanovectors, challenges and opportunities in marine algae, and genetic identification and mass propagation of economically important seaweeds and seaweeds as source of new bioactive prototypes

    PXY collaboration with other cambial regulators, ER, and MP, is essential for secondary growth

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    Plants grow both in height, and in width. The process of radial expansion, known as secondary growth, generates the majority of the plant biomass through expansion of the vasculature, the plant’s water and nutrient conducting tissues. It is therefore imperative to understand how vascular growth is regulated. Secondary growth is facilitated by a collection of stem cells present in a meristem called the vascular cambium. The cambium gives rise to the water-conducting xylem and nutrient conducting phloem, on opposing sides via periclinal cell divisions. A receptor-like kinase PXY has been found to promote cell division in the cambium, and to control its ability to maintain distinct domains for xylem and phloem. Loss of PXY results in interspersal of these cell types. PXY interacts with other components in regulating secondary growth. It was seen to genetically interact with another receptor-kinase and its family of genes, ER. However, comprehensive exploration of how these two genes and their families interact had not been determined. Similarly, PXY was shown to indirectly suppress the transcription factor MP in stem, but to be promoted by MP in root. Both components were also found to be localized in the same domain on the xylem side of the cambium, where the hormone auxin was shown to accumulate. Disruption of the auxin pattern or removal of PXY or MP results in defects in cambial function, but the basis of these interactions is not fully understood. To address the questions surrounding PXY’s role in secondary growth, a bespoke method for measuring cell sizes and shapes from cross-sections of plants was developed. This method was employed to analyse PXY and ER families single and combinatorial mutants. Finally, a theoretical three-cell mathematical model was proposed examining PXY’s relationship with the transcription factor MP in controlling the accumulation of auxin in the cambium. The results of these studies demonstrated that loss of PXY and ER families results in different consequences in stem and hypocotyl. In hypocotyl and in the absence of the PXY family, ER and its genetic paralogues promote hypocotyl radial growth in part, compensating for loss of PXY by promoting cell size increases, but this was not observed in stem. Moreover, loss of all of the PXY and ER genes results in complete suspension of secondary growth, suggesting that these two genetic pathways are required for the transition between primary and secondary growth. In the investigation of PXY’s relationship with the transcription factor MP in root, it was shown both numerically and analytically that a negative feedback loop between the two provides stability to the system, thus generating a more stable auxin gradient in the cambium. Thus, PXY interacts with both ER and MP to maintain vascular organisation and growth, and these interactions are essential for the induction of secondary expansion, as well as hormone patterning in order to promote cambial activity

    Complexity in Developmental Systems: Toward an Integrated Understanding of Organ Formation

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    During animal development, embryonic cells assemble into intricately structured organs by working together in organized groups capable of implementing tightly coordinated collective behaviors, including patterning, morphogenesis and migration. Although many of the molecular components and basic mechanisms underlying such collective phenomena are known, the complexity emerging from their interplay still represents a major challenge for developmental biology. Here, we first clarify the nature of this challenge and outline three key strategies for addressing it: precision perturbation, synthetic developmental biology, and data-driven inference. We then present the results of our effort to develop a set of tools rooted in two of these strategies and to apply them to uncover new mechanisms and principles underlying the coordination of collective cell behaviors during organogenesis, using the zebrafish posterior lateral line primordium as a model system. To enable precision perturbation of migration and morphogenesis, we sought to adapt optogenetic tools to control chemokine and actin signaling. This endeavor proved far from trivial and we were ultimately unable to derive functional optogenetic constructs. However, our work toward this goal led to a useful new way of perturbing cortical contractility, which in turn revealed a potential role for cell surface tension in lateral line organogenesis. Independently, we hypothesized that the lateral line primordium might employ plithotaxis to coordinate organ formation with collective migration. We tested this hypothesis using a novel optical tool that allows targeted arrest of cell migration, finding that contrary to previous assumptions plithotaxis does not substantially contribute to primordium guidance. Finally, we developed a computational framework for automated single-cell segmentation, latent feature extraction and quantitative analysis of cellular architecture. We identified the key factors defining shape heterogeneity across primordium cells and went on to use this shape space as a reference for mapping the results of multiple experiments into a quantitative atlas of primordium cell architecture. We also propose a number of data-driven approaches to help bridge the gap from big data to mechanistic models. Overall, this study presents several conceptual and methodological advances toward an integrated understanding of complex multi-cellular systems

    Improving the Value of the Coconut with Biotechnology

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    The fruit of the coconut tree is perhaps the most useful plant resource in the tropics. All parts of the coconut fruit have traditional uses that have been developed commercially in recent times (Foale 2003, Dayrit and Dayrit 2013). Due to its widespread household use, trade and industry statistics on coconut products reflect only part of the actual importance of the coconut. Today, coconut-based products have gone beyond the tropics and are consumed in many temperate countries and global regions such as Australia, China, Europe, North America, and the Middle East (Costello 2018). Coconut milk is the basic ingredient of traditional cuisines and desserts worldwide in the Asian tropics, while coconut flour is used in confectionery and bakery products. Coconut oil is widely used as cooking oil, hair and cosmetic oil, and domestic remedies for burns and skin ailments and in soap-making and preparation of traditional medicine. Coconut water can be either consumed fresh or converted into vinegar and nata de coco. The residues of these processes are used for animal feed and soil enhancer. The young inflorescences can be tapped directly to obtain coconut sap. This natural honey-like product can then be evaporated to prepare coco sugar or fermented to produce coconut sap wine and vinegar. These products are markedly distinct from those produced from coconut water. However, if the sap is collected, the harvest of nuts is lost. Nondairy products from the coconut, such as margarines, yoghurts, and cheese, have become more and more popular in the global market. This chapter will deal mainly with the products that can be obtained from the fruit

    The nature of growth in the biofuel feedstock and bloom-forming green macroalga Ulva

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    Ulva is a genus of multicellular green algae that is phylogenetically similar to uni- cellular green algae such as Chlamydomonas and Ostreococcus. Ulva is present in much of the coastal benthic zones worldwide, and is of great interest for three main reasons. Firstly, Ulva is an important feedstock for biofuels. Secondly, many Ulva species are massively proliferating organisms that cause Harmful Algal Blooms, which are ecologically devastating. Finally, Ulva is an important model organism that could elucidate the evolution of multicellularity. This thesis investigates the physiology of growth in Ulva in four sequential results chapters. The first establishes a statistical proof for the goodness of fit of gene family occupancy data to a discrete power law model. This was an assumption used in the only Ulva genome study, which found no genomic signature for multicellularity. This establishes the baseline for the in- vestigation of bottom-up morphogenesis in Ulva. The second is the investigation of differential growth, by identifying cell tessellation patterns in different morphologies of Ulva thalli, namely the “ribbon” and “leaf” morphotypes, with mathematical mod- els using Voronoi tessellations. The third expands investigates differential growth in the ribbon and leaf morphotypes with a focus on identifying potential mechanisms with further mathematical models using Centroidal Voronoi Tessellations. The fourth aims to develop experimental techniques to confirm the hypotheses arising from the mathematical modelling in the second and third chapters. The first part involves the use of EdU cellular proliferation assays. The remainder of the chapter will investigate the development of a live-imaging biomass monitoring system that aims to improve the accuracy, reliability and temporal resolution of aquatic biomass measurements. It can be concluded that Ulva does not show a genomic signature for multicellularity, and bottom-up mechanisms likely explain its morphogenesis and morphologies

    FUNKČNÍ ANALÝZA VYBRANÝCH PODJEDNOTEK EXOCYSTU EXO70 U ROSTLIN

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    Unikátnost trichomů Arabidopsis thaliana tkví ve spojení jejich jednobuněčnosti a specifického tvaru, a tak jsme trichomy využili jako skvělý modelový systém pro výzkum mechanismů buněčné polarizace. Vývoj rostlinného těla je silně určen mechanismy buněčné polarizace a proteinový komplex exocyst je jed- ním z jejich klíčových regulátorů. Exocyst je tvořen osmi různými podjednotkami a při polarizované exo- cytóze váže sekretorické váčky na cílové membráně. Podjednotka EXO70 pomocí interakce s fosfolipidy značí konkrétní místo exocytózy na cílové membráně. Pozoruhodné zmnožení genů podjednotky EXO70 v rostlinných genomech je již obstojně zdokumentováno, nicméně zmapování funkční rozrůzněnosti jed- notlivých paralogů zatím schází. Studiem trichomů jsme odhalili specifickou funkci paralogu EXO70H4 ve vývoji sekundární bu- něčné stěny trichomu a především sekreci kalózo-syntáz. V divokém trichomu jsme popsali utváření tlus- té sekundární buněčné stěny během fáze dozrávání a její absenci u mutanta exo70H4. Dále jsme prokázali vztah mezi ukládáním křemíku a přítomností kalózy. Také jsme odhalili rozdělení plazmatické mem- brány trichomu na apikální a bazální doménu plazmatické membrány, které se liší složením fosfolipidů a schopností vázat různé paralogy EXO70. Naše výsledky mají potenciál širšího využití...Arabidopsis thaliana trichomes are large unicellular epidermal outgrowths with a specific development and intriguing shape, which makes them an excellent cell type for our research of cell polarization mecha- nisms. Cell polarity is essential for plant development and the exocyst complex is one of its key regulators. It is an octameric protein complex that mediates polarized exocytosis and growth by targeted tethering of secretory vesicles to the plasma membrane. Its EXO70 subunit functions as a landmark for exocytosis site and physically binds the target membrane through interaction with phospholipids. A remarkable multipli- cation of EXO70 subunit paralogs in land plant genomes is well documented, but the functional diversity of these paralogs remains to be described. In trichomes we revealed the specific role of the EXO70H4 paralog in secondary cell wall deposi- tion, especially in callose synthase delivery. We documented formation of a thick secondary cell wall during the maturation phase of wild type trichome development and a lack of it in the exo70H4 mutant. Moreover, we showed evidence for silica deposition dependency on callose synthesis. Further, we unveiled the formation of apical and basal plasma membrane domains, which differ in their phospholipid compo- sition and ability to bind...Katedra experimentální biologie rostlinDepartment of Experimental Plant BiologyPřírodovědecká fakultaFaculty of Scienc
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