Biology Commons^™

Mir319a Targeting Of Tcp4 Is Critical For Petal Growth And Development In Arabidopsis, Anwesha Nag, Stacey King, Thomas Jack

Dartmouth Scholarship

In a genetic screen in a drnl-2 background, we isolated a loss-of-function allele in miR319a (miR319a¹²⁹). Previously, miR319a has been postulated to play a role in leaf development based on the dramatic curled-leaf phenotype of plants that ectopically express miR319a (jaw-D). miR319a¹²⁹ mutants exhibit defects in petal and stamen development; petals are narrow and short, and stamens exhibit defects in anther development. The miR319a¹²⁹ loss-of-function allele contains a single-base change in the middle of the encoded miRNA, which reduces the ability of miR319a to recognize targets. Analysis of the expression patterns of the …

Remote Sensing Of Harmful Algal Blooms In The Mississippi Sound And Mobile Bay: Modelling And Algorithm Formation, Dan Martin Holiday

Dissertations

The incidence and severity of harmful algal blooms have increased in recent decades, as have the economic effects of their occurrence./The diatom Pseudo-nitzschia spp. caused fisheries closures in Mobile Bay during 2005 due to elevated levels of domoic acid. In the previous 4 years Karenia brevis counts of >5,000 cells L"1 have occurred in Mobile Bay and the Mississippi Sound. Population levels of this magnitude had previously been recorded only in 1996. Increases in human populations, urban sprawl, development of shoreline properties, sewage effluent and resultant changes in NP ratios of discharge waters, and decline in forest and marsh lands, …

Mojave Applied Ecology Notes Fall 2009, Tom Monaco, Scott R. Abella, Amber Lee, James E. Deacon

Mojave Applied Ecology Notes

USDA working to manage invasive annual grasses, effects of heat and smoke on red brome soil seed bank, how burial depth and substrate affect germination of Sahara mustard and red brome, environmental effects of the southern Nevada groundwater project

Life History, Sexual Dimorphism And 'Ornamental' Feathers In The Mesozoic Bird Confuciusornis Sanctus., Winfried S. Peters, Dieter Stefan Peters

Winfried S. Peters

Foraging Preference By Wild Deer On Toyon Populations From Santa Catalina Island Versus The Santa Monica Mountains, Amelia I. Clark, Rodney Honeycutt, Anjel Helms, Stephen Davis

Biology

Post-fire regeneration of Toyon (Heteromeles arbutifolia), a chaparral shrub on Santa Catalina Island is impeded by mule deer (Odocoileus hemionus), a non-native species introduced during the 1930’s. Mainland and island populations of Toyon were examined for potential differences in defense mechanisms that act as natural deterrents to over-browsing by ungulate herbivores, with the hypothesis that island populations, void of natural ungulate herbivores, may lack such defense mechanisms. Several characteristics of leaf morphology, including number and length of spines, leaf area and depth, and tensile strength of leaves, were compared between island and mainland populations. Leaves of Toyon from Santa Catalina …

Spatial And Seasonal Variations In Mercury Methylation And Microbial Community Structure In A Historic Mercury Mining Area, Yolo County, California, J. M. Holloway, M. B. Goldhaber, K. M. Scow, Rebecca E. Drenovsky

Biology

The relationships between soil parent lithology, nutrient concentrations, microbial biomass and community structure were evaluated in soils from a small watershed impacted by historic Hg mining. Upland and wetland soils, stream sediments and tailings were collected and analyzed for nutrients (DOC, SO4=, NO3−), Hg, MeHg, and phospholipid fatty acids (PLFA). Stream sediment was derived from serpentinite, siltstone, volcanic rocks and mineralized serpentine with cinnabar, metacinnabar and other Hg phases. Soils from different parent materials had distinct PLFA biomass and community structures that are related to nutrient concentrations and toxicity effects of trace metals including Hg. The formation of MeHg appears …

Impact Of Weed Management Practices On Grapevine Growth, Yield Components, Plant And Arthropod Abundance, And Carabid Seed Predation In Paso Robles Vineyard, Paolo Sanguankeo

Master's Theses

In the Central Coast of California, USA, wine grape growers are making efforts to identify weed control practices that promote biodiversity in their vineyards while maintaining yields. A field study was conducted in Paso Robles, CA in 2006 and 2007 evaluating the effect on Zinfandel grape-vine growth and production, groundcover plant, and ground dwelling arthropod communities of five weed control practices: 1) flumioxazin, 2) simazine, 3) cultivation, 4) cover crop, and 5) untreated control.

The herbicide treatments had the lowest weed biomass followed by the cultivation, being approximately 10 and 2 times lower than the weed biomass of either the …

Mojave Applied Ecology Notes Summer 2009, Kevin E. Oliver, Dianne N. Bangle, E. Cayenne Engel, Lindsay P. Chiquoine, Scott R. Abella

Mojave Applied Ecology Notes

BLM and wildfire protection in the Mojave, studies of the sticky ringstem flowering phenology in Lake Mead NRA, restoration work within gypsum soils, post-fire response synthesis for Mojave and Sonoran deserts

Genetic And Phenotypic Characterization Of Plant Pathogen Inhibitory Streptomyces Isolates, Uylissa A. Rodriguez

Theses and Dissertations - UTB/UTPA

Streptomyces are Gram-positive, filamentous bacteria that are readily isolated from soil and produce diverse secondary metabolites such as pigments and antibiotics. A survey of indigenous soil microbes from Rio Grande Valley agricultural soils revealed several isolates with broad inhibitory abilities against a range of soil-borne plant pathogens. The goal of this study was to characterize eleven of these potential biocontrol isolates both biochemically and genetically. Nutrient utilization profiles, 16S rDNA sequencing, and the presence of genes involved in antibiotic biosynthesis pathways (strBl, strR, strF, strN, strS and KS) on plasmids or the chromosome were investigated. Nutrient utilization profiling revealed that …

An Examination Of The Correlation Between Shoot Apical Meristem Size And Leaf Heterophylly In Pisum Sativum, Cynthia Mary Halfman

Undergraduate Honors Thesis Collection

This study is a quantitative examination of the ramifications of leaf development as influenced by the size of the shoot apical meristem. I wish not to delve into a genetic examination of the shoot apical meristem but rather into the possible correlation between the apical meristem size and leaf heterophylly. If changes in shoot apical meristem size influence heterophylly in leaves, then as shoot apical meristem changes, leaf characteristics will change. This change may result from two different relationships.

An Analysis Of The Environmental And Hormonal Effects On The Growth And Development Of The Moss Ceratodon Purpureus, Megan Knight

Undergraduate Honors Thesis Collection

Ceratodon has not been documented in scientific literature as thoroughly as other species of moss such as Funaria or Tortula. Commonly known as fire moss or purple horned moss, Ceratodon is often reddish or yellow-brown and the spore capsules are usually purple (Crum, 1983). A picture of the species growing in its natural habitat is shown in Figure 4. Ceratodon often grows in tufts and is considered a weed, often thriving in polluted or disturbed areas and frequently invading after a fire (Crum 1983). Ceratodon belongs to the class Bryopsida, which also contains the previously mentioned Funaria and Tortula species. …

Genetic Change Following Fire In Populations Of A Seed-Banking Perennial Plant, Rebecca W. Dolan, Pedro F. Quintana-Ascencio, Eric S. Menges

Rebecca W. Dolan

Disturbances such as fire have the potential to remove genetic variation, but seed banks may counter this loss by restoring alleles through a reservoir effect. We used allozyme analysis to characterize genetic change in two populations of the perennial Hypericum cumulicola, an endemic of the fire-prone Florida scrub. We assessed genetic variation before and 1, 2, and 3 years after fire that killed nearly all aboveground plants. Populations increased in size following fire, with most seedlings likely recruited from a persistent seed bank. Four of five loci were variable. Most alleles were present in low frequencies, but our large sample …

A New Species Of Streptanthus (Brassicaceae) From Three Peaks In Lake County, California, Rebecca W. Dolan, Richard O'Donnell

Rebecca W. Dolan

Streptanlhus vernalis is a newly described species inhabiting serpentine rock outcrops in the Three Peaks area in Lake County, California. Morphological and allozyme data indicate that this taxon is related to the S. morrisonii complex.

Mojave Applied Ecology Notes Spring 2009, Russell Scofield, Michele Slaton Ph.D, Alexis Suazo, Donovan J. Craig

Mojave Applied Ecology Notes

California desert managers group, vegetation monitoring in Death Valley, undergraduate research symposium at UNLV, response of Sahara mustard to water and disturbance, JFS update

Graminicolous Fungi Of Virginia: Fungi In Collections 2004-2007, Curtis W. Roane

Virginia Journal of Science

Fungus-grass associations recognized in Virginia from 2004 to 2007 are recorded. Many associations are new to the United States (U), eastern United States (EU) and Virginia (V); other associations extend the known distribution of those previously discovered. These reports contribute further to knowledge of the mycoflora of Virginia.

Dispersal And Establishment Both Limit Colonization During Primary Succession On A Glacier Foreland, Chad C. Jones, Roger Del Moral

Botany Faculty Publications

Plant colonization can be limited by lack of seeds or by factors that reduce establishment. The role of seed limitation in community assembly is being increasingly recognized, but in early primary succession, establishment failure is still considered more important. We studied the factors limiting colonization on the foreland of Coleman Glacier, Washington, USA to determine the importance of seed and establishment limitation during primary succession. We also evaluated the effects of seed predation, drought and existing vegetation on establishment. We planted seeds of seven species into plots of four different ages and found evidence that both seed and establishment limitation …

Mojave Applied Ecology Notes Winter 2009, Scott R. Abella, Lindsay P. Chiquoine, Alice C. Newton

Mojave Applied Ecology Notes

Chronology of forest structure and use in the Spring Mountains, Soil-Tech’s restoration work balancing construction with nature, species performance and treatment effectiveness for revegetation projects, and strategic research areas for Mojave conservation and management

7tmrmine: A Web Server For Hierarchical Mining Of 7tmr Proteins, Guoqing Lu, Zhifang Wang, Alan M. Jones, Etsuko N. Moriyama

Biology Faculty Publications

Background: Seven-transmembrane region-containing receptors (7TMRs) play central roles in eukaryotic signal transduction. Due to their biomedical importance, thorough mining of 7TMRs from diverse genomes has been an active target of bioinformatics and pharmacogenomics research. The need for new and accurate 7TMR/GPCR prediction tools is paramount with the accelerated rate of acquisition of diverse sequence information. Currently available and often used protein classification methods (e.g., profile hidden Markov Models) are highly accurate for identifying their membership information among already known 7TMR subfamilies. However, these alignment-based methods are less effective for identifying remote similarities, e.g., identifying proteins from highly divergent or possibly …

Environmental Stress And Genetics Influence Night-Time Leaf Conductance In The C4 Grass Distichlis Spicata, Rebecca E. Drenovsky, Mairgareth A. Christman, Jeremy J. James, James H. Richards

Biology

Growing awareness of night-time leaf conductance (gnight) in many species, as well as genetic variation in gnight within several species, has raised questions about how genetic variation and environmental stress interact to influence the magnitude of gnight. The objective of this study was to investigate how genotype salt tolerance and salinity stress affect gnight for saltgrass [Distichlis spicata (L.) Greene]. Across genotypes and treatments, night-time water loss rates were 5–20% of daytime rates. Despite growth declining 37–87% in the high salinity treatments (300 mM and 600 mM NaCl), neither treatment had any effect on gnight in four of the six …

Demographics And Habitat Selection For The Western Meadowlark (Sturnella Neglecta) In The Nebraska Sandhills, Matthew D. Giovanni

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The prairie ecosystems of the Great Plains region in North America have largely been replaced and fragmented with industrial agriculture and invasive herbaceous and woody plant species. The concurrent and large-scale suppression of wildfire and elimination of grazing by native ungulates may have further decreased the availability and quality of habitat for wildlife. Indeed, 2004 estimates indicate only 30% of historic grasslands in the Great Plains still exist, while the trends of decreased land area enrolled in the Conservation Reserve Program and increased land area in commercial agriculture indicate continued loss of habitat. This decrease in habitat availability continues to …

Life In The Slow Lane: Palmetto Seedlings Exhibit Remarkable Survival But Slow Growth In Florida's Nutrient-Poor Uplands, W. G. Abrahamson, C. R. Abrahamson

Warren G. Abrahamson, II

The palmettos Serenoa repens and Sabal etonia are crucial foundation species in many peninsular Florida vegetative associations. We monitored the survival and growth of individual palmetto seedlings using two cohorts found in different vegetative associations. Seedling cohorts containing both S. repens and S. etonia were individually tagged in 1989 and have been monitored until 2008, a period of 19 years. One cohort (N = 100 seedlings) occurs in a xeric, “inopina-phase” scrubby flatwoods and a second cohort (N =78 seedlings) lives in a well-drained, “wiregrass-phase” flatwoods. The soils at both sites are very nutrient-poor Entisols that show rapid permeability, low …