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Articles 271 - 300 of 5489
Full-Text Articles in Life Sciences
Abiotic Stress Responses In Photosynthetic Organisms, Joseph Msanne
Abiotic Stress Responses In Photosynthetic Organisms, Joseph Msanne
School of Natural Resources: Dissertations, Theses, and Student Research
Cellular and molecular aspects of abiotic stress responses in Arabidopsis thaliana subjected to cold, drought, and high salinity and in two photosynthetic green alga, Chlamydomonas reinhardtii and Coccomyxa sp. C-169, subjected to nitrogen deprivation were investigated. Cold, drought, and high salinity can negatively affect plant growth and crop production. The first research aimed at determining the physiological functions of the stress-responsive Arabidopsis thaliana RD29A and RD29B genes. Cold, drought, and salt induced both genes; the promoter of RD29Awas found to be more responsive to drought and cold stresses, whereas the promoter of RD29B was highly responsive to salt stress. …
Management Zone Delineation Techniques On Irrigated Corn In Nebraska, Aaron M. Bereuter
Management Zone Delineation Techniques On Irrigated Corn In Nebraska, Aaron M. Bereuter
Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research
Increased interest in site-specific management of irrigated corn in Nebraska has identified the need for a decision-making framework for zone delineation. Zones based on static soil and landscape properties provide a valuable foundation for variable rate management strategies. The purpose of this project was to identify the optimal soil and landscape attributes for generating management zones (MZ) of relative productivity potential. Three producer-managed cornfields across Nebraska with varying soil types, topographic characteristics, and climate regimes were identified as research sites during the 2010 growing season. Nine soil and landscape attributes were identified as potential properties for estimation of productivity potential. …
Synthesis Of An Antimicrobial Textile Coating, William M. Morris
Synthesis Of An Antimicrobial Textile Coating, William M. Morris
Chemistry and Biochemistry
A titania nanosol was synthesized and coated onto nylon/cotton blended textile substrates. The substrates were characterized via SEM for adhesion and nanoparticle formation, then subjected to antimicrobial efficacy tests. The titania nanosol was successfully coated on to textiles samples. Particles were observed to be around 2 by 3 micrometers and formed between the interstitial space of textile fibers. Although larger than typical nanoparticles, the coatings exhibited what seemed to be antimicrobial activity. Titania nanosol coated textile samples were subjected to Kirby Bauer Assay in the presence of S. aureus. The coated textile sample exhibited an inhibition of growth around its …
The Effect Of Amylase Supplementation With Low-Starch Rations: Effects On Milk Production And Feed Consumption, Alfred Eaton
The Effect Of Amylase Supplementation With Low-Starch Rations: Effects On Milk Production And Feed Consumption, Alfred Eaton
Dairy Science
The objective of this trial was to determine if there was an increase in milk production or a decrease in feed consumption by dairy cattle when fed an exogenous rumen-resistant amylase, named RumiStar. High feed prices have caused dairymen to look for new ways to be more efficient. Commercial feed additives have been proposed as opportunities to improve efficiency. In our study a minimum of eighty multiparous Holstein cows were assigned to each of two pens, with a minimum of forty cows in each. Cows that completed their lactation during the study period were replaced with fresh cows to keep …
Protein Trap Lines Of Drosophila To Demonstrate Spatio-Temporal Localization Of Proteins In An Undergraduate Lab, Oorvashi Roy Puli, Amit Singh
Protein Trap Lines Of Drosophila To Demonstrate Spatio-Temporal Localization Of Proteins In An Undergraduate Lab, Oorvashi Roy Puli, Amit Singh
Biology Faculty Publications
The objective of this teaching note is to generate a laboratory exercise, which allows students to get a hands-on experience of a cell biology technique. The short duration of the laboratory classes is the biggest challenge with the development of a cell biology lab for an undergraduate curriculum. Therefore, it is necessary to design a laboratory exercise that enables the students to carry out cell biological assays in the desired time. This laboratory exercise focuses on tracking protein expression levels along a spatial (space) and temporal (time) axis in developing Drosophila melanogaster organ primordium. Here we use the protein trap …
Characterization And Molecular Analysis Of University Of Arkansas Peach, Prunus Persica (L.) Batsch, Flesh Types And Development Of A Post-Harvest Evaluation Protocol For Arkansas Peach And Nectarine Genotypes, Paul James Sandefur
Graduate Theses and Dissertations
This study determined the effect of pre-cold storage treatment on P. persica genotypes, developed a protocol for the evaluation of breeding selection and cultivar storage performance, and provided information on post-harvest performance of these individuals. Additionally, characterization of the peach and nectarine flesh types, validation of endopolygalacturonase (endoPG) DNA markers, and investigation of endoPG marker allele combinations associated with the slow-melting-flesh (SMF) trait were done.
Fruit from 30 individuals were harvested at minimum- and well-mature states. After conditioning for 24 h at 20 ◦C, all 2010 fruit were exposed to 2 min of 1 ◦C 100 ppm chlorinated hydro-cooling, a …
The Role Of Atpase In The Development Of Idiopathic Pulmonary Arterial Hypertension In Broilers, Jessica Worley
The Role Of Atpase In The Development Of Idiopathic Pulmonary Arterial Hypertension In Broilers, Jessica Worley
Biological Sciences Undergraduate Honors Theses
The goal of this study was to assess the ATPase activity in the vascular walls of the pulmonary artery, 1A arteriole, and 2A arteriole of the lung of broilers susceptible to idiopathic pulmonary arterial hypertension. This was achieved through the modification of tryptophan in the diet and through the examination of the ATPase activity in the different pulmonary vessels. A QuantiChrom ATPase assay quantified the amount of phosphate ion correlating to the amount of ATPase activity, which was normalized for vessel size using the Coomassie and MicroBCA Protein Assays (giving ?M of phosphate/?g of protein per mL). One way repeated …
Environmental Impact Of The Three Kids Mine Tailings, Henderson, Nv, Ji Hye Park
Environmental Impact Of The Three Kids Mine Tailings, Henderson, Nv, Ji Hye Park
UNLV Theses, Dissertations, Professional Papers, and Capstones
This research focused on the distribution of the Three Kids Mine tailings in surface soils in and around the mine in Henderson, Nevada. It is situated next to the communities of Calico Ridge and Lake Las Vegas Resort, and, just the west of the Lake Mead Recreation area. Even though the mine has been inactive for almost 50 years (1917-1961), tailing piles and other sources of contamination on the mine are currently exposed to the atmosphere. In this study, surface soil samples were collected along eight transects emanating from the center of Three Kids Mine tailing piles up to five …
State Space Model With Hidden Variables For Reconstruction Of Gene Regulatory Networks, Xi Wu, Peng Li, Nan Wang, Ping Gong, Edward J. Perkins, Youping Deng, Chaoyang Zhang
State Space Model With Hidden Variables For Reconstruction Of Gene Regulatory Networks, Xi Wu, Peng Li, Nan Wang, Ping Gong, Edward J. Perkins, Youping Deng, Chaoyang Zhang
Faculty Publications
Background: State Space Model (SSM) is a relatively new approach to inferring gene regulatory networks. It requires less computational time than Dynamic Bayesian Networks (DBN). There are two types of variables in the linear SSM, observed variables and hidden variables. SSM uses an iterative method, namely Expectation-Maximization, to infer regulatory relationships from microarray datasets. The hidden variables cannot be directly observed from experiments. How to determine the number of hidden variables has a significant impact on the accuracy of network inference. In this study, we used SSM to infer Gene regulatory networks (GRNs) from synthetic time series datasets, investigated …
Environmental Regulation Of Dormancy Loss In Seeds Of Lomatium Dissectum, Melissa Dawn Scholten
Environmental Regulation Of Dormancy Loss In Seeds Of Lomatium Dissectum, Melissa Dawn Scholten
Boise State University Theses and Dissertations
Lomatium dissectum (Nutt.) Mathias & Constance is a perennial plant found across much of western North America. For disturbed lands within this range, there is interest in using L. dissectum in restoration. A problem in the propagation of L. dissectum is that at the time of dispersal the seeds are dormant. Thus, prior to usage in restoration projects the type of dormancy and the procedures necessary to release dormancy in these seeds must be determined. Determining the type of dormancy and the treatments necessary to break dormancy in L. dissectum seeds was the primary focus of this study. To approach …
Modeling Spread Of Polio With The Role Of Vaccination, Manju Agarwal, Archana S. Bhadauria
Modeling Spread Of Polio With The Role Of Vaccination, Manju Agarwal, Archana S. Bhadauria
Applications and Applied Mathematics: An International Journal (AAM)
In this paper, we have proposed and analyzed a nonlinear mathematical model for the spread of Polio in a population with variable size structure including the role of vaccination. A threshold parameter, R , is found that completely determines the stability dynamics and outcome of the disease. It is found that if R 1, the disease free equilibrium is stable and the disease dies out. However, if R >1, there exists a unique endemic equilibrium that is locally asymptotically stable. Conditions for the persistence of the disease are determined by means of Fonda’s theorem. Moreover, numerical simulation of the proposed …
Cost-Effective Binomial Sequential Sampling Of Western Bean Cutworm, Striacosta Albicosta (Lepidoptera: Noctuidae), Egg Masses In Corn, S. Paula-Moraes, E. C. Burkness, Thomas E. Hunt, Robert Wright, Gary Hein, W. D. Hutchinson
Cost-Effective Binomial Sequential Sampling Of Western Bean Cutworm, Striacosta Albicosta (Lepidoptera: Noctuidae), Egg Masses In Corn, S. Paula-Moraes, E. C. Burkness, Thomas E. Hunt, Robert Wright, Gary Hein, W. D. Hutchinson
Department of Entomology: Faculty Publications
Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), is a native pest of dry beans (Phaseolus vulgaris L.) and corn (Zea mays L.). As a result of larval feeding damage on corn ears, S. albicosta has a narrow treatment window; thus, early detection of the pest in the field is essential, and egg mass sampling has become a popular monitoring tool. Three action thresholds for field and sweet corn currently are used by crop consultants, including 4% of plants infested with egg masses on sweet corn in the silking-tasseling stage, 8% of plants infested with egg masses on field corn with …
Invasion Triangle: An Organizational Framework For Species Invasion, Lora B. Perkins, Elizabeth A. Leger, Robert S. Nowak
Invasion Triangle: An Organizational Framework For Species Invasion, Lora B. Perkins, Elizabeth A. Leger, Robert S. Nowak
Natural Resource Management Faculty Publications
Species invasion is a complex, multifactor process. To encapsulate this complexity into an intuitively appealing, simple, and straightforward manner, we present an organizational framework in the form of an invasion triangle. The invasion triangle is an adaptation of the disease triangle used by plant pathologists to help envision and evaluate interactions among a host, a pathogen, and an environment. Our modification of this framework for invasive species incorporates the major processes that result in invasion as the three sides of the triangle: (1) attributes of the potential invader; (2) biotic characteristics of a potentially invaded site; and (3) environmental conditions …
Current Status And Long-Term Trends In Water Quality And Living Resources In The Virginia Tributaries And Chesapeake Bay Mainstem From 1985 Through 2010, Daniel M. Dauer, Harold G. Marshall, John R. Donat, Michael F. Lane, Suzanne C. Doughten, Frederick A. Hoffman, Raghavendra Kurada
Current Status And Long-Term Trends In Water Quality And Living Resources In The Virginia Tributaries And Chesapeake Bay Mainstem From 1985 Through 2010, Daniel M. Dauer, Harold G. Marshall, John R. Donat, Michael F. Lane, Suzanne C. Doughten, Frederick A. Hoffman, Raghavendra Kurada
Status and Trends for Virginia Chesapeake Bay
The period prior to the implementation of the Chesapeake Bay Monitoring Program was characterized by a marked decline in the water quality of the Chesapeake Bay. The disappearance of submerged aquatic vegetation in certain regions of the Bay, declines in the abundance of some commercially and recreationally important species, increases in the incidence of low dissolved oxygen events, changes in the Bay's food web, and other ecological problems have been related to the deteriorating water quality (e.g. USEPA, 1982,1983;Officer et al.,1984; Orth and Moore, 1984). The results of concentrated research efforts in the late 1970s and early 1980s stimulated the …
Preliminary Evaluations Of Secondary Productivity Estimates As Indicators Of The Ecological Value Of The Benthos To Higher Trophic Levels In Chesapeake Bay, Daniel M. Dauer, Michael F. Lane, Roberto J. Llansó, Robert Diaz
Preliminary Evaluations Of Secondary Productivity Estimates As Indicators Of The Ecological Value Of The Benthos To Higher Trophic Levels In Chesapeake Bay, Daniel M. Dauer, Michael F. Lane, Roberto J. Llansó, Robert Diaz
Benthic Applications
The primary objective of this project was to develop an analytical tool that management could use to assess the ecological value of the benthos for higher trophic levels. Ideally any tool developed should be simple to implement, adaptable to both fixed and probability monitoring programs and applicable across multiple spatial and temporal scales. Direct evaluations of secondary productivity involve time-consuming cohort or size-based methods that require multiple measurements of the populations in question over time (Dolbeth et al., 2005; Cusson and Bourget, 2005). However, empirical regression models have been developed that provide reasonable alternatives to these techniques when direct measurements …
The Update, December 2011, University Of Northern Iowa. College Of Humanities, Arts And Sciences.
The Update, December 2011, University Of Northern Iowa. College Of Humanities, Arts And Sciences.
Update
Inside this issue:
-- Two UNI Alums to Graduate with Doctoral Degrees
-- Department News
-- UNI Department of Theatre: Guernica Re-Cap
-- Art High School Scholarship Day
-- Faculty member Awarded Fellowship
-- School of Music Events
-- Student Spotlight: Department of Art: Erlinda Babauta
-- Military Veteran and UNI Alumnus Joins the Center for Teaching and Learning Mathematics
-- UNI Geology Students Explore Heavy Metal: Learning How to Rock!
-- Modern Motives: Influences in Today's Art
-- New U.S.-Brazil Program in Communication Disorders
-- Student Spotlight: Department of Math: Nathan Bradfield
Ecology Of Ticks (Acari: Ixodidae) In Shelterbelts Of Southeastern Nebraska, Matthew W. Yans
Ecology Of Ticks (Acari: Ixodidae) In Shelterbelts Of Southeastern Nebraska, Matthew W. Yans
Department of Entomology: Dissertations, Theses, and Student Research
Shelterbelts in the agricultural landscape provide valuable habitat to a variety of animals that in turn may be hosts to ixodid ticks. The purpose of this study is to determine if shelterbelt associated factors influence tick ecology. In 2010 and 2011, ticks were collected from several shelterbelts in southeast Nebraska in Lancaster and Saunders counties. Four tick species were identified.
Adjacent land use, shelterbelt composition, and time of day were all factors which did not influence the number of questing ticks collected. Differences in relation to aspect and distance from the shelterbelt were significant. The east side had continually higher …
First Records Of Paralaoma Servilis (Shuttleworth, 1852) (Gastropoda: Pulmonata: Punctidae) In The Hawaiian Islands, Carl Christensen, Norine Yeung, Kenneth Hayes
First Records Of Paralaoma Servilis (Shuttleworth, 1852) (Gastropoda: Pulmonata: Punctidae) In The Hawaiian Islands, Carl Christensen, Norine Yeung, Kenneth Hayes
Department of Biology Faculty Publications
We report the establishment of another globally invasive land snail species in the Hawaiian islands. Punctidae Paralaoma servilis (Shuttleworth, 1852) New state record Cowie et al. (1995) and Cowie (1997) reported the occurrence on the island of Hawai'i of an unidentified land snail tentatively assigned to the genus Striatura (Family Zonitidae). We now identify this species as Paralaoma servilis (Shuttleworth, 1852) (Family Punctidae) and report its occurrence also on the island of O'ahu (Fig. 1).
Multiple Paths To Encephalization And Technical Civilizations, David Schwartzman, George Middendorf
Multiple Paths To Encephalization And Technical Civilizations, David Schwartzman, George Middendorf
Department of Biology Faculty Publications
We propose consideration of at least two possible evolutionary paths for the emergence of intelligent life with the potential for technical civilization. The first is the path via encephalization of homeothermic animals; the second is the path to swarm intelligence of so-called superorganisms, in particular the social insects. The path to each appears to be facilitated by environmental change: homeothermic animals by decreased climatic temperature and for swarm intelligence by increased oxygen levels.
Exploring The Effects Of Hypoxia On Sulfate Reducing Anaerobes, Annaliese K. Jones
Exploring The Effects Of Hypoxia On Sulfate Reducing Anaerobes, Annaliese K. Jones
Senior Honors Projects
Exploring the Effects of Hypoxia on Sulfate Reducing Anaerobes
Annaliese K. Jones
Sponsor: Bethany Jenkins, Cell and Molecular Biology
As a student about to graduate with a degree in Biological Sciences, I find myself faced with the need to find my own independent research interests and scientific voice. As a result of my interests in the fields of both microbiology and ecology, I am drawn to questions surrounding the role and behavior of microorganisms in the environment. With climate change being an issue capturing the attention of a large portion of the scientific community, I have chosen to focus my …
The Relationship Of Strength And Body Composition To Vertical Jump Ability In Division 1 Female Volleyball Players., Alyssa Shedlarski
The Relationship Of Strength And Body Composition To Vertical Jump Ability In Division 1 Female Volleyball Players., Alyssa Shedlarski
Undergraduate Honors Theses
Jump ability is important in volleyball; therefore analysis of factors that influence jump performance is necessary to ensure maximal jump ability. Purpose: To analyze how strength characteristics associated with jumping are affected by percent body fat, lean body mass and free fat mass. Methods: Data from eleven female NCAA DI volleyball players as part of an ongoing athlete monitoring program collected from 2007-2010 was analyzed. Data was separated into weakest and strongest based on isometric peak force allometrically scaled. In all cases the weakest data corresponded to testing during the athletes first year at ETSU. Body composition was measured using …
Quantitative Comparison Of Cis-Regulatory Element (Cre) Activities In Transgenic Drosophila Melanogaster, William A. Rogers, Thomas M. Williams
Quantitative Comparison Of Cis-Regulatory Element (Cre) Activities In Transgenic Drosophila Melanogaster, William A. Rogers, Thomas M. Williams
Biology Faculty Publications
Gene expression patterns are specified by cis-regulatory element (CRE) sequences, which are also called enhancers or cis-regulatory modules. A typical CRE possesses an arrangement of binding sites for several transcription factor proteins that confer a regulatory logic specifying when, where, and at what level the regulated gene(s) is expressed. The full set of CREs within an animal genome encodes the organism′s program for development1, and empirical as well as theoretical studies indicate that mutations in CREs played a prominent role in morphological evolution2-4. Moreover, human genome wide association studies indicate that genetic variation in CREs …
Influence Of Detritus Levels And Organic Pollution On Interspecific Resource Competition, Oviposition Behavior, And Larval Survival Of Two Tire-Inhabiting Mosquito Species (Diptera: Culicidae), David Wayne Allgood
Master's Theses
Mosquitoes (Diptera: Culicidae) are vectors of disease in the adult stage, but understanding the factors affecting distributions of the immature stages is important to the understanding and control of adult populations. Discarded automobile tires comprise important larval mosquito habitats. The Asian tiger mosquito (Aedes albopictus) and the southern house mosquito (Culex quinquefasciatus) are two medically important species commonly found in tires, but factors affecting their larval distributions in tires have not been studied, nor have their interspecific interactions. I investigated the effects of chemicals associated with organic pollution on oviposition preferences and larval survival of both …
Tick Infestations And Their Consequences For Migratory Songbirds During Spring Stopover, Johnny Michael Sellers Jr.
Tick Infestations And Their Consequences For Migratory Songbirds During Spring Stopover, Johnny Michael Sellers Jr.
Master's Theses
Migratory birds face a number of challenges during their seasonal movement from tropical/sub-tropical Central and South America to more temperate North America. Maintaining health during migration is of particular concern. This study seeks to understand how haematophageous ectoparasites, such as ticks (Ixodida), impact host body condition as they feed on passerines during migration. We hypothesized that foraging location would impact tick acquisition by migrants and that tick burdens during migration would negatively impact body condition. We surveyed 2,064 birds during spring 2009 and 2010 and found that 2.4% of the surveyed birds were infested with one or more …
Thermal Tolerance Of Age-0 Gulf Of Mexico Striped Bass (Morone Saxatilis): Ontogenetic And Genetic Effects, Corey Robert Anderson
Thermal Tolerance Of Age-0 Gulf Of Mexico Striped Bass (Morone Saxatilis): Ontogenetic And Genetic Effects, Corey Robert Anderson
Master's Theses
Striped bass, Morone saxatilis, were historically abundant in the Gulf of Mexico region but were largely extirpated from most Gulf rivers by the early 1960s. Since 1967 hatchery stocking has supported populations in Mississippi rivers and to date there is no evidence of natural reproduction. Intolerance of striped bass to high water temperature is a potential factor negatively impacting Gulf striped bass survival and reproductive fitness, and may be a limiting factor to reintroduction of the species in Mississippi. This work contributed to restoration efforts by establishing molecular tools necessary for genetic monitoring of striped bass restoration, and evaluating …
Measuring And Comparing Quantum Yield In Two Species Of Marine Diatoms Subjected To Constant And Fluctuating Light Conditions, Matthew Leon Stone
Measuring And Comparing Quantum Yield In Two Species Of Marine Diatoms Subjected To Constant And Fluctuating Light Conditions, Matthew Leon Stone
Master's Theses
A small-scale study was conducted to determine the effects of light fluctuations on the photosynthetic efficiency of marine phytoplankton. Two species, Phaeodactylum tricornutum and Chaetoceros gracile were grown in specialized photobioreactors on a 12-hour:12-hour light:dark cycle. The cultures were diluted 50% daily to attain a specific growth rate of 0.70 d-1. To simulate vertical mixing in high turbidity habitats under various wind conditions, dense cultures were subjected to fluctuating light treatments with frequencies ranging from 0.10 Hz to 2.00 Hz. Parallel experiments subjected the cultures to static light conditions with equal total daily light doses as those of the cultures …
Quantifying Rates Of Autocompaction In The Pearl River Marsh, Louisiana, Jeremiah Nicholas Prouhet
Quantifying Rates Of Autocompaction In The Pearl River Marsh, Louisiana, Jeremiah Nicholas Prouhet
Master's Theses
Annual rates of shallow autocompaction (< 1 m) were calculated in the upper ~one meter of sediment from six cores of a transect in the Pearl River Marsh (PRM), Louisiana, in order to determine the most significant sedimentary property controlling this process. Compaction-free wedge cores were sub-sampled at one centimeter intervals to collect the following data: age control, using 137Cs and 210Pb, and sedimentary variables, specifically, particulate organic carbon, bulk density, median grain size, porosity, and water content. An upper and an underlying sedimentary unit (named the 137Cs and 210Pb units) were defined between radiometric datum levels, and their sedimentary properties were statistically tested for significant differences using the non-parametric Mann-Whitney test. Rates of autocompaction were calculated from the model of Williams (2003), and both rates of autocompaction and sedimentation were tested for significant differences between the upper and lower sedimentary units.
The upper unit in the six cores generally had lower bulk density, higher water content, higher porosity, and higher particulate organic carbon than the underlying unit, but with some interesting exceptions. Additionally, annual autocompaction and sedimentation rates were greatest in the overlying unit at stations PR02 (0.39 ± 0.05 cm/y) and PR05 (0.42 ± 0.03 cm/y) and greatest in the underlying unit at stations PR02 (0.22 ± 0.08 cm/y) and PR03 (0.18 ± 0.06 cm/y). Based on Spearman correlations, rates of autocompaction were most strongly correlated to and influenced by rates of sedimentation rather …
Phytoplankton Abundance And Species Composition In Relation To Environmental Paramenters In Coastal Mississippi Waters, Luz Karime Molina
Phytoplankton Abundance And Species Composition In Relation To Environmental Paramenters In Coastal Mississippi Waters, Luz Karime Molina
Master's Theses
Phytoplankton pigments from Coastal Mississippi waters were measured to determine the spatial and temporal distributions and composition of phytoplankton communities. Concentration of phytoplankton pigments were analyzed using High Performance Liquid Chromatography (HPLC) and the compositional changes in phytoplankton communities were determined with CHEMTAX 1.95. Surface water was collected for two years (September 2007-November 2009) at three sampling sites on a monthly basis. The stations were located at the Bay of St. Louis (station 1), the Mississippi Sound (station 4) and the Mississippi Bight (station 8), following a salinity gradient. A time series of the observations documented the variability of different …
The Use Of Computed Tomography To Measure Biogenic Structures In Recently Hypoxic And Normoxic Sediments On The Louisiana Continental Shelf, Valerie Ann Hartman
The Use Of Computed Tomography To Measure Biogenic Structures In Recently Hypoxic And Normoxic Sediments On The Louisiana Continental Shelf, Valerie Ann Hartman
Master's Theses
Over the past 60 years, seasonal hypoxia in the northern Gulf of Mexico has occurred with increased severity and over a greater area. To determine if biogenic structures in the northern Gulf of Mexico vary in response to hypoxic stress, the seafloor on the continental shelf of Louisiana was analyzed during the spring and fall of 2009 at four provinces of similar sediment type that differ in recent history of bottom water oxygen concentration. Subcores were analyzed by computed tomography (CT) to determine the number, diameter, length, volume, surface area, and depth of biogenic burrow structures in sediments where biogenic …
Drosophila Piwi Functions Downstream Of Pirna Production Mediating A Chromatin-Based Transposon Silencing Mechanism In Female Germ Line, Sidney Wang, Sarah C.R. Elgin
Drosophila Piwi Functions Downstream Of Pirna Production Mediating A Chromatin-Based Transposon Silencing Mechanism In Female Germ Line, Sidney Wang, Sarah C.R. Elgin
Biology Faculty Research
Transposon control is a critical process during reproduction. The PIWI family proteins can play a key role, using a piRNA-mediated slicing mechanism to suppress transposon activity posttranscriptionally. In Drosophila melanogaster, Piwi is predominantly localized in the nucleus and has been implicated in heterochromatin formation. Here, we use female germ-line-specific depletion to study Piwi function. This depletion of Piwi leads to infertility and to axis specification defects in the developing egg chambers; correspondingly, widespread loss of transposon silencing is observed. Germ-line Piwi does not appear to be required for piRNA production. Instead, Piwi requires Aubergine (and presumably secondary piRNA) for proper …