Biology Commons^™

Characterization Of The Alternative Oxidase From The Psychrophilic Green Alga Chlamydomonas Sp. Uwo241, Michael Sj Inman

Electronic Thesis and Dissertation Repository

The alternative oxidase (AOX) was studied in the psychrophilic green alga Chlamydomonas sp. UWO241. AOX is the sole component of the alternative pathway of mitochondrial electron transport and is present in all plant and algal species. In silico analysis of the deduced protein sequence of the cloned AOX cDNA showed that the UWO241 protein has lower amounts of proline and higher amounts of lysine and tryptophan compared to the AOX sequence of the mesophilic alga C. reinhardtii. These changes have been seen in other studies of cold-adapted enzymes. Interestingly, unlike C. reinhardtii, AOX transcript abundance in UWO241 …

Effects Of Excitation Pressure On Variegation And Global Gene Expression In Arabidopsis Thaliana, Rainer Bode

Electronic Thesis and Dissertation Repository

I assessed the effects of photosystem II excitation pressure on chloroplast biogenesis and leaf sectoring in the Arabidopsis thaliana variegated mutants im, spotty, var1, var2, chs5 and atd2. The plants were grown under varying degrees of excitation pressure induced by growth at increasing irradiance at different temperatures and the extent of variegation was quantified throughout the plant’s development. I found that the degree of variegation was positively correlated with excitation pressure, regardless of whether high light or low temperature was used to induce increased excitation pressure in all the mutants tested. This was irrespective of …

Toward Target 2 Of The Global Strategy For Plant Conservation: An Expert Analysis Of The Puerto Rican Flora To Validate New Streamlined Methods For Assessing Conservation Status, James S. Miller, Gary A. Krupnick, Hannah Stevens, Holly Porter-Morgan, Brian Boom, Pedro Acevedo-Rodríguez, James Ackerman, Duane Kolterman, Eugenio Santiago, Christian Torres, Jeanine Velez

Publications and Research

Target 2 of the 2020 Global Strategy for Plant Conservation (GSPC) calls for a comprehensive list of the world's threatened plant species. The lack of such a list is one of the greatest impediments to protecting the full complement of the world's plant species, and work to achieve this has been slow. An efficient system for identifying those species that are at risk of extinction could help to achieve this goal in a time frame sensitive to today's conservation needs. Two systems that efficiently use available data to assess conservation status were tested against a provisional International Union for Conservation …

Census And Mapping Of Chorro Creek Bog Thistle In Reservoir Canyon, San Luis Obispo, Ca, Tyler Michael Lutz

Biological Sciences

Chorro Creek bog thistle (Cirsium fontinale var. obispoense) is a federally endangered variety of Fountain thistle endemic to western San Luis Obispo County. The U.S. Fish and Wildlife Service knows of nineteen populations, many with multiple colonies. A population was discovered in the Reservoir Canyon Natural Reserve in 2001, but has not been monitored or described since the time of its discovery. In fall of 2013, a census of the population was performed, the four colonies were mapped, and a floristic survey was conducted. A field experiment was initiated to determine if reducing the riparian canopy coverage can …

Development And Application Of A Gis-Based Long Island Sound Eelgrass Habitat Suitability Index Model, Jamie M.P. Vaudrey, Justin Eddings, Christopher Pickerell, Lorne Brousseau, Charles Yarish

Department of Marine Sciences

The primary objectives of the Eelgrass Habitat Suitability Index Model (EHSI Model) are to assist in the evaluation of sites being considered for eelgrass restoration efforts in the Long Island Sound (LIS) area and to identify areas where water quality issues reduce or eliminate the potential for natural eelgrass colonization. To achieve this goal, geospatial processing of data available from the Long Island Sound area was conducted using ArcGIS v10.0 including the 3D Analyst and Spatial Analyst extensions. The result is a series of maps presented in this report and a GIS-based model available for users to interact with the …

Mechanisms For Regulation Of Plant Kinesins, Anindya Ganguly, Ram Dixit

Biology Faculty Publications & Presentations

Throughout the eukaryotic world, kinesins serve as molecular motors for the directional transport of cellular cargo along microtubule tracks. Plants contain a large number of kinesins that have conserved as well as specialized functions. These functions depend on mechanisms that regulate when, where and what kinesins transport. In this review, we highlight recent studies that have revealed conserved modes of regulation between plant kinesins and their non-photosynthetic counterparts. These findings lay the groundwork for understanding how plant kinesins are differentially engaged in various cellular processes that underlie plant growth and development.

A Seasonal, Density-Dependent Model For The Management Of An Invasive Weed, Esther Shyu, Eleanor A. Pardini, Tiffany M. Knight, Hal Caswell

Biology Faculty Publications & Presentations

The population effects of harvest depend on complex interactions between density dependence, seasonality, stage structure, and management timing. Here we present a periodic nonlinear matrix population model that incorporates seasonal density dependence with stage-selective and seasonally selective harvest. To this model, we apply newly developed perturbation analyses to determine how population densities respond to changes in harvest and demographic parameters. We use the model to examine the effects of popular control strategies and demographic perturbations on the invasive weed garlic mustard (Alliaria petiolata). We find that seasonality is a major factor in harvest outcomes, because population dynamics may …

The Influence Of Hydrogeomorphology, Soil Redox Conditions, And Salinity On The Spatial Zoning Of Saltgrass, Salt Rush, And Cattails In Scotts Creek Marsh, Swanton Pacific Ranch, Ca, Mark D. Gormley

Master's Theses

Scotts Creek Marsh (SCM) is a small coastal wetland ecosystem in Davenport, CA. The vegetation of SCM is dominated by three halophytic zones comprised of saltgrass, salt rush, cattails. The objectives of the study were (i) to investigate the variables that influence the zoning of the three dominant halophyte communities in SCM and (ii) to the test the effectiveness of Indicator of Reduction in Soil (IRIS) tubes to indicate the reduction of S. The study examined the following parameters from April 6 to July 21, 2013: (i) the HGM of Scotts Creek Marsh, (ii) soil oxidation and reduction (redox) conditions, …

Assessing Growth Response To Climate Controls In A Great Basin Artemisia Tridentata Plant Community, Lorenzo F. Apodaca

UNLV Theses, Dissertations, Professional Papers, and Capstones

An assessment of the growth response of key vegetative species to climatic variability is vital to identifying possible local impacts on ecosystems faced with imminent climate change. With current climate projections in Nevada predicting a shift to an even more arid climate with greater year-to-year variability, the imperative exists to identify the effects of specific climatic controls on plant growth and to research methods to assess large-scale vegetative changes, especially in more remote areas where readily available data sets may be lacking. This study utilized annual growth ring indices constructed from big sagebrush (Artemisia tridentatassp.tridentata) stems collected in Spring Valley, …

Differences In Temperature Responses Of Achene Types In Centaurea Melitensis, Kandee L. Bain

LUX: A Journal of Transdisciplinary Writing and Research from Claremont Graduate University

Southern California has a Mediterranean climate with wet winters and hot dry summers. This type of environment is associated with irregular temperature patterns and rainfall, which can be unpredictable. Unpredictable environments, can threaten the germination and survival of plants like Centaurea melitensis. To ensure germination and survival under unpredictable environmental conditions, some plants may develop characteristic structures like cleistogamous flower heads, and in some cases they will develop heteromorphic achenes. Morphological differences between peripheral and center achenes may indicate variable responses to temperature. Additionally, unpredictable environmental conditions may lead to differences in the number of peripheral to center achenes …

Microtubule Severing At Crossover Sites By Katanin Generates Ordered Cortical Microtubule Arrays In Arabidopsis, Quan Zhang, Erica Fishel, Tyler Bertroche, Ram Dixit

Biology Faculty Publications & Presentations

Highlights

• Severing primarily depolymerizes the overlying CMT at crossover sites
• Severing probability increases nonlinearly with crossover time
• Katanin localizes to crossover sites and is required for severing
• Loss of katanin activity prevents the formation of coaligned CMT arrays

Summary
The noncentrosomal cortical microtubules (CMTs) of land plants form highly ordered parallel arrays that mediate cell morphogenesis by orienting cellulose deposition [1, 2 and 3]. Since new CMTs initiate from dispersed cortical sites at random orientations [4], parallel array organization is hypothesized to require selective pruning of CMTs that are not in the dominant orientation. Severing of CMTs at crossover sites …

Effect Of Mycorrhizal Colonization And Light Limitation On Growth And Reproduction Of Lima Bean (Phaseolus Lunatus L.), Daniel J. Ballhorn, Jess A. Millar

Biology Faculty Publications and Presentations

Plants can respond with sink stimulation of photosynthesis when colonized with fungal or bacterial root symbionts, compensating costs of carbohydrate allocation to the microbes. However, constraints may arise under light limitation when plants cannot extensively increase photosynthesis. We hypothesize that under such conditions the costs for maintaining the symbiosis outweigh the benefits, ultimately turning the mutualist microbes into parasites, resulting in reduced plant growth and reproduction.

Using lima bean (Phaseolus lunatus) as experimental plant, we applied two levels of light (full light, 75% shading) and microbial inoculation (sterile soil, mycorrhizal fungi) and quantified both vegetative and generative plant …

Decomposition Patterns And Nitrogen Dynamics Of Black Mangrove (Avicennia Germinans)Leaf Litter In Disturbed Estuaries Linked To The Lower Laguna Madre, Texas, Mario Alberto Marquez

Theses and Dissertations - UTB/UTPA

Estuaries are among the most productive aquatic systems in the world but are subject to both anthropogenic and natural disturbances. With increasing environmental concerns, efforts have become commonplace in assessing the status and trends of environmental conditions. In this study, an assessment of ecosystem status of various estuaries affected by different disturbances, was attempted through the examination of key functional processes such as leaf litter decomposition and nutrient dynamics during decay. Three estuaries located along the Brownsville Ship Channel near the southern terminus of the Lower Laguna Madre in Texas were studied. The overlying goal of this study was to …

Heterologous Production And Characterization Of Cell Wall Degrading Enzymes Using Plants As A Bioreactor, Eridan Orlando Rodrigues Pereira

Electronic Thesis and Dissertation Repository

Plants are wonderful living organisms. They are able to store solar energy into carbohydrates by fixing CO₂ through photosynthesis which can be subsequently harvested and used for fuel production. However, one of the major limitations for transforming these carbohydrates into liquid fuels is the recalcitrance of the plant cell wall. Although microorganisms have evolved a series of cell wall degrading enzymes to harvest efficiently this energy and are considered the main source of these biocatalysts, harnessing these microorganisms for the production of enzymes is a costly process and a major factor limiting the commercialization of lignocellulosic biomass-to-ethanol processes. The …

Microclimate Moderates Plant Responses To Macroclimate Warming, Pieter De Frenne, Francisco Rodríguez-Sánchez, David Anthony Coomes, Lander Baeten, Gorik Verstraeten, Mark Vellend, Markus Bernhardt-Römermann, Carissa D. Brownd, Jörg Brunet, Johnny Cornelis, Guillaume M. Decocq, Hartmut Dierschke, Ove Eriksson, Frank S. Gilliam, Radim Hédl, Thilo Heinken, Martin Hermy, Patrick Hommel, Michael A. Jenkins, Daniel L. Kelly, Keith J. Kirby, Fraser J. G. Mitchell, Tobias Naaf, Miles Newman, George Peterken, Petr Petrík, Jan Schultz, Grégory Sonnier, Hans Van Calster, Donald M. Waller, Gian-Reto Walther, Peter S. White, Kerry D. Woods, Monika Wulf, Bente Jessen Graae, Kris Verheyen

Biological Sciences Faculty Research

Recent global warming is acting across marine, freshwater, and terrestrial ecosystems to favor species adapted to warmer conditions and/or reduce the abundance of cold-adapted organisms (i.e., “thermophilization” of communities). Lack of community responses to increased temperature, however, has also been reported for several taxa and regions, suggesting that “climatic lags” may be frequent. Here we show that microclimatic effects brought about by forest canopy closure can buffer biotic responses to macroclimate warming, thus explaining an apparent climatic lag. Using data from 1,409 vegetation plots in European and North American temperate forests, each surveyed at least twice over an interval of …

Incorporating Satellite Derived Cloud Climatologies To Improve High Resolution Interpolation Of Daily Precipitation., Adam M. Wilson, Benoit Parmentier, Brian Mcgill, Rob Guralnick, Walter Jetz

Yale Day of Data

Conservation of biodiversity demands comprehension of evolutionary and ecological patterns and processes that occur over vast spatial and temporal scales. A central goal of ecology is to understand the factors that control the spatial distribution of species and this has become even more important in the face of climate change. However, at global scales there can be enormous uncertainty in environmental data used to model species distributions. Even ‘simple’ metrics such as mean annual precipitation are difficult to estimate in areas with few weather stations and available data sets do not quantify uncertainty in these surfaces. We are developing a …

Subset Of Heat-Shock Transcription Factors Required For The Early Response Of Arabidopsis To Excess Light, Hou-Sung Jung, Peter A. Crisp, Gonzalo M. Estavillo, Benjamin Cole

Dartmouth Scholarship

Sunlight provides energy for photosynthesis and is essential for nearly all life on earth. However, too much or too little light or rapidly fluctuating light conditions cause stress to plants. Rapid changes in the amount of light are perceived as a change in the reduced/oxidized (redox) state of photosynthetic electron transport components in chloroplasts. However, how this generates a signal that is relayed to changes in nuclear gene expression is not well understood. We modified redox state in the reference plant, Arabidopsis thaliana, using either excess light or low light plus the herbicide DBMIB (2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone), a well-known inhibitor of photosynthetic …

Dirigent Domain-Containing Protein Is Part Of The Machinery Required For Formation Of The Lignin-Based Casparian Strip In The Root, Prashant S. Hosmani, Takehiro Kamiya, John Danku, Sadaf Naseer, Niko Geldner, Mary Lou Guerinot, David Salt

Dartmouth Scholarship

The endodermis acts as a "second skin" in plant roots by providing the cellular control necessary for the selective entry of water and solutes into the vascular system. To enable such control, Casparian strips span the cell wall of adjacent endodermal cells to form a tight junction that blocks extracellular diffusion across the endodermis. This junction is composed of lignin that is polymerized by oxidative coupling of monolignols through the action of a NADPH oxidase and peroxidases. Casparian strip domain proteins (CASPs) correctly position this biosynthetic machinery by forming a protein scaffold in the plasma membrane at the site where …

Mscs-Like Mechanosensitive Channels In Plants And Microbes, Margaret E. Wilson, Grigory Maksaev, Elizabeth S. Haswell

Biology Faculty Publications & Presentations

The challenge of osmotic stress is something all living organisms must face as a result of environmental dynamics. Over the past three decades, innovative research and cooperation across disciplines have irrefutably established that cells utilize mechanically gated ion channels to release osmolytes and prevent cell lysis during hypoosmotic stress. Early electrophysiological analysis of the inner membrane of Escherichia coli identified the presence of three distinct mechanosensitive activities. The subsequent discoveries of the genes responsible for two of these activities, the mechanosensitive channels of large (MscL) and small (MscS) conductance, led to the identification of two diverse families of mechanosensitive channels. …

Traversing Swanton Road, 13th Ed., James A. West

Academic, Government & Associated Organizational Research Resources

Situated at the northwest end of Santa Cruz County and occupying circa 30 square miles of sharply contrasted terrain, the Scott Creek Watershed concentrates within its geomorphological boundaries, at least 10-12% of California's flora, both native and introduced. Paradoxically, the use/abuse that the watershed has sustained over the past 140+ years, has not necessarily diminished the biodiversity and perhaps parallels the naturally disruptive but biologically energizing processes (fire, flooding, landslides and erosion), which have also been historically documented for the area for +60 years. This is an early edition of an extensive document by James A. West. Please visit the …

Identifying Molecular Markers Associated With Salt And Boron Tolerance In Poplar Trees, Darshanpreet Gill, Nathan Follen, Davis W. Cheng, Kyan Salehi, Gary Banuelos, James P. Prince

STAR Program Research Presentations

Standard irrigation practices promote salt and boron accumulation in soils on the Westside of Central California. The build-up of these inorganic salts leads to the degradation of arable land and reduction of crop production. Different clones of poplar trees have been shown to grow in salt- and boron-contaminated soils, and in doing so, gradually remove significant amounts of these inorganic salts from the soil. In an effort to identify molecular markers linked with salt and boron tolerance in poplars, 31 PCR primer pairs have been designed based on candidate genes identified from the literature, and an additional 31 PCR primer …

Leaf Mechanical Strength Predicts Physiological Traits Among Three Life History Types In California Chaparral, Taylor S. Stucky, Nicole M. Rodriguez Purcell, Stephen D. Davis

Featured Research

The Santa Monica Mountains of southern California are located in a Mediterranean-type climate region which experiences reoccurring wildfires due to summer drought and Santa Ana winds. Chaparral vegetation, which consists mostly of evergreen, sclerophyllous shrubs, dominates the landscape. Species of chaparral shrubs have evolved three different life history types in response to fire – those that sprout after fire but do not germinate seeds (obligate sprouters = OS), those that do not sprout after fire but reestablish by seed germination (non-sprouters = NS), and those that both sprout and germinate seeds after fire (facultative sprouters = FS). There are two …

A Force Of Nature: Molecular Mechanisms Of Mechanoperception In Plants, Gabriele B. Monshausen, Elizabeth S. Haswell

Biology Faculty Publications & Presentations

The ability to sense and respond to a wide variety of mechanical stimuli-gravity, touch, osmotic pressure, or the resistance of the cell wall-is a critical feature of every plant cell, whether or not it is specialized for mechanotransduction. Mechanoperceptive events are an essential part of plant life, required for normal growth and development at the cell, tissue, and whole-plant level and for the proper response to an array of biotic and abiotic stresses. One current challenge for plant mechanobiologists is to link these physiological responses to specific mechanoreceptors and signal transduction pathways. Here, we describe recent progress in the identification …

Vegetation Response After Invasive Tamarix Spp. Removal In The Riparian Zone And Semi-Arid Rangeland Ecosystems, Hisham Nagi El Waer

Electronic Theses and Dissertations

Removal of Tamarix spp. (a.k.a. tamarisk, saltcedar, Athel) invasion is often involved in restoration of Western, riparian habitat; however monitoring of vegetation after removal is often neglected and thus opportunity for adaptive management lost. To address this need, I have conducted three and half years of monitoring vegetation response after invasive Tamarix removal in twenty-five sites on the East and Western Colorado, starting fall 2009. I am also comparing six different methodologies: Point intercept, line transect, nearest neighbor, meter-square quadrats, nested Whittaker plots, and densitometer with the objective of developing monitoring protocols that can be used by …

Thorns Of Native Lower Rio Grande Valley Plants Are Colonized By Potentially Pathogenic Bacteria, Felicia A. Charles

Theses and Dissertations - UTB/UTPA

Epiphytic pathogenic bacteria on the thorns of native LRGV plants may provide a defense mechanism for the plants. To test this, plant thorns were collected from LRGV plant species and aerobic and anaerobic bacteria were isolated in thioglycollate medium. Tests were performed to characterize the bacterial cultures. The 16S rRNA gene was sequenced to allow for species identification. Sixty-nine bacterial cultures were isolated, including gram-positive and gram-negative cell types. All utilized a variety of carbon sources for nutrients and 23% of isolates displayed hemolysis. Bacterial identification included members of the genus Bacillus, Pseudomonas, Serratia, and others. Most were opportunistic pathogens. …

Characterization Of A Putative Activation Domain In The Hulk Gene Family, Christopher Doan

Electronic Thesis and Dissertation Repository

The HULK gene family participates in regulation of both flowering time and development in the plant Arabidopsis thaliana. The proteins encoded by these genes share conserved domain structures including a proline-rich region (PRR) in the carboxyl-terminus. Based on sequence analysis and the presence of a proline-rich domain, it has been suggested that the HULKs are putative transcription factors in which HUA2 is known to regulate several late-flowering genes: FLC, FLM and MAF2.

To investigate the putative transcriptional activation domain in the carboxyl-terminus of the HULKs, full-length HULKs and deletion constructs were 3-AT titrated in yeast-one hybrids. It …

Early Inflorescence Development In The Grasses (Poaceae), Elizabeth Kellogg, Paulo Camara, Paula Rudall, Philip Ladd, Simon Malcomber, Clinton Whipple, Andrew Doust

Biology Department Faculty Works

The shoot apical meristem of grasses produces the primary branches of the inflorescence, controlling inflorescence architecture and hence seed production. Whereas leaves are produced in a distichous pattern, with the primordia separated from each other by an angle of 180◦, inflorescence branches are produced in a spiral in most species. The morphology and developmental genetics of the shift in phyllotaxis have been studied extensively in maize and rice. However, in wheat, Brachypodium, and oats, all in the grass subfamily Pooideae, the change in phyllotaxis does not occur; primary inflorescence branches are produced distichously. It is unknown whether the distichous inflorescence …

Identification Of Cyclophilin Gene Family In Soybean And Characterization Of Gmcyp1, Hemanta Raj Mainali

Electronic Thesis and Dissertation Repository

I identified members of the Cyclophilin (CYP) gene family in soybean (Glycine max) and characterized the GmCYP1, one of the members of soybean CYP. CYPs belong to the immunophilin superfamily with peptidyl-prolyl cis-trans isomerase (PPIase) activity. PPIase catalyzes the interconversion of the cis- and trans-rotamers of the peptidyl-prolyl amide bond of peptides. After extensive data mining, I identified 62 different CYP genes in soybean (GmCYP1 to GmCYP62), of which 8 are multi-domain proteins and 54 are single domain proteins. At least 25% of the GmCYP genes are expressed in soybean. GmCYP1 …

The Effects Of Arbuscular Mycorrhizal Fungi On Four Legume Hosts In South Florida Pine Rockland Soils, Klara Scharnagl

FIU Electronic Theses and Dissertations

This study addressed the effects of salinity and pot size on the interaction between leguminous plant hosts and arbuscular mycorrhizal fungi in four pine rockland soils using a shade house trap-plant experiment. Little is known about the belowground diversity of pine rocklands and the interactions between aboveground and belowground biota – an increased understanding of these interactions could lead to improved land management decisions, conservation and restoration efforts. Following twelve weeks of growth, plants were measured for root and shoot dry biomass and percent colonization by arbuscular mycorrhizal fungi. Overall, arbuscular mycorrhizal fungi had positive fitness effects on the four …

Climate Change And Plant Demography In The Sagebrush Steppe, Aldo Compagnoni

Green Canyon Environmental Research Area, Logan Utah

No abstract provided.