Identification and characterization of proteins expressed in the nectar of ornamental tobacco

A small set of proteins, termed Nectarins, are secreted into the nectar of ornamental tobacco (Nicotiana langsdorffii x Nicotiana sanderae). The most highly expressed protein, Nectarin I (29 kD monomer), was originally identified as a germin-like protein (GLP) of unknown function. This remarkably stable protein was later shown to possess manganese dependent superoxide dismutase activity. Hydrogen peroxide, the product of SOD activity, was found to accumulate in nectar at levels up to 4 mM. The promoter (1.2 kb) of the Nectarin I gene was fused to the reporter gene chloramphenicol acetyl transferase (CAT) and shown to be expressed in mature nectary tissues only at times when nectar is actively being secreted.;Nectarin II (35 kD) was identified as a dioscorin-like protein and found to be a degradation product of Nectarin III (40 kD). These proteins were shown to posses monodehydroascorbate reductase and carbonic anhydrase activity. Nectarin V (~65 kD) was identified as a berberine bridge enzyme-like protein and found to contain a covalently bound molecule of FAD. Both Nectarin III and Nectarin V shared very similar expression patterns with those of Nectarin I.;The hypothesis of this work is that nectar proteins are secreted into nectar to maintain an axenic state and to protect the developing gynoecium from microbial attack and oxidative damage. Specifically, the proposed functions of these nectar proteins include: the production of hydrogen peroxide for floral defense, maintenance of nectar pH, and maintenance of ascorbate levels in nectar

Keys of War

At the dawn of time the gods created heaven and earth. The creator of the moon joined with the creator of the sun and together they produced the first Empress. She is the embodiment of all that is good and holy. She is the spiritual guide to all the tribes of man. The tribes are ruled by men. When one man, Baron Stier, rises above the others he is crowned Archduke. He rules in the Empress’s name and his dynasty lasts for half a millennia. Upon the discovery of the land beyond the sacred islands the dynasty falls. And tribes enter into a period of civil war. The civil wars represent an unstable time. Barons of the tribes fight among themselves for generations with no real gain. But one day through strong virtue and miraculous fortune young Indar finds the strength to unify a nation. This is the second dynasty. His first order is to strip the people of their weapons. His second order is to redistribute the land so the tribes closest to him are the tribes that are the most loyal to him. It is a bold plan, but it is the order that sews the seeds of revolution. The anger of the disenfranchised smolders for two hundred years. Because the tribes are sealed off from the outside world a strong and popular black market arises. During a certain illegal transaction Baron Reisht comes to possess a flashlight. It is a technology that is so far beyond anything he has seen, he becomes afraid. In a rare and special moment, something akin to genius, he understands that his country, his home, is in grave danger. The creators of this technology could conquer the tribes at their leisure. Baron Reisht will not let that happen. The Baron, with unholy determination, marshals his forces and brings to the people he intends to protect destruction on an order they have never before seen. But he is successful. He captures the throne and establishes the third dynasty. On the day of his triumph his greatest fears come true

TRUST IN TECHNOLOGY: DEVELOPMENT OF A SET OF CONSTRUCTS AND MEASURES

Trust plays an important role in many Information Systems (IS)-enabled situations. Most IS research employs trust as a measure of interpersonal or interfirm relations, such as trust in a Web vendor or a virtual team member. Although trust in other people is important, this paper suggests that trust in the information technology (IT) itself may also play a role in shaping IT-related beliefs and behavior. To advance trust and technology research, this paper presents a set of trust in technology construct definitions and measures. These construct measures will be examined using tests of convergent, discriminant, and nomological validity. This study will contribute to the literature by offering a) a framework for distinguishing between trust in people and trust in technology, b) offering a theory based set of definitions necessary forminvestigating different forms of trust, and c) developing measures useful to research and practice for evaluating trust in technology

Effects of Struggle and Goal Achievement in Weight-Loss Journeys on Social Media: Instilling Hope and Promoting Health Behaviors

Weight-loss journeys are frequently depicted in social media attempting to inspire others to achieve their health goals. In a 3 X 2 experimental design, this thesis examines how social media posts about weight-loss goals achieved, in progress, or unattained, and that mention or do not mention struggle in the pursuit, affect self-efficacy, social comparison, target perceptions, hope and, in turn, intention to model the author’s health behaviors. Mixed support arose for the predicted effects of social comparison and how struggle expressed in a weight-loss narrative and personal struggle interact to impact self-efficacy to perform modeled strategies. The findings support Social Cognitive Theory’s main tenet that an individual’s self-efficacy is central to whether or not a modeled behavior is emulated. The results suggest personal struggle with a weight-loss helps determine whether an individual will perceive similarity with and feel hopefulness in response to weight-loss narratives. Implications for health promotion are discussed.Master of Art

Uncovering the Arabidopsis thaliana nectary transcriptome: investigation of differential gene expression in floral nectariferous tissues

<p>Abstract</p> <p>Background</p> <p>Many flowering plants attract pollinators by offering a reward of floral nectar. Remarkably, the molecular events involved in the development of nectaries, the organs that produce nectar, as well as the synthesis and secretion of nectar itself, are poorly understood. Indeed, to date, no genes have been shown to directly affect the <it>de novo </it>production or quality of floral nectar. To address this gap in knowledge, the ATH1 Affymetrix^®GeneChip array was used to systematically investigate the Arabidopsis nectary transcriptome to identify genes and pathways potentially involved in nectar production.</p> <p>Results</p> <p>In this study, we identified a large number of genes differentially expressed between secretory lateral nectaries and non-secretory median nectary tissues, as well as between mature lateral nectaries (post-anthesis) and immature lateral nectaries (pre-anthesis). Expression within nectaries was also compared to thirteen non-nectary reference tissues, from which 270 genes were identified as being significantly upregulated in nectaries. The expression patterns of 14 nectary-enriched genes were also confirmed via RT PCR. Upon looking into functional groups of upregulated genes, pathways involved in gene regulation, carbohydrate metabolism, and lipid metabolism were particularly enriched in nectaries versus reference tissues.</p> <p>Conclusion</p> <p>A large number of genes preferentially expressed in nectaries, as well as between nectary types and developmental stages, were identified. Several hypotheses relating to mechanisms of nectar production and regulation thereof are proposed, and provide a starting point for reverse genetics approaches to determine molecular mechanisms underlying nectar synthesis and secretion.</p

Bathymetric Artifacts in Sea Beam Data: How to Recognize Them and What Causes Them

Sea Beam multibeam bathymetric data have greatly advanced understanding of the deep seafloor. However, several types of bathymetric artifacts have been identified in Sea Beam\u27s contoured output. Surveys with many overlapping swaths and digital recording on magnetic tape of Sea Beam\u27s 16 acoustic returns made it possible to evaluate actual system performance. The artifacts are not due to the contouring algorithm used. Rather, they result from errors in echo detection and processing. These errors are due to internal factors such as side lobe interference, bottom-tracking gate malfunctions, or external interference from other sound sources (e.g., 3.5 kHz echo sounders or seismic sound sources). Although many artifacts are obviously spurious and would be disregarded, some (particularly the omega effects described in this paper) are more subtle and could mislead the unwary observer. Artifacts observed could be mistaken for volcanic constructs, abyssal hill trends, hydrothermal mounds, slump blocks, or channels and could seriously affect volcanic, tectonic, or sedimentological interpretations. Misinterpretation of these artifacts may result in positioning errors when seafloor bathymetry is used to navigate the ship. Considering these possible geological misinterpretations, a clear understanding of the Sea Beam system\u27s capabilities and limitations is deemed essential

Biophysical Measurements of Cells, Microtubules, and DNA with an Atomic Force Microscope

Atomic force microscopes (AFMs) are ubiquitous in research laboratories and have recently been priced for use in teaching laboratories. Here we review several AFM platforms (Dimension 3000 by Digital Instruments, EasyScan2 by Nanosurf, ezAFM by Nanomagnetics, and TKAFM by Thorlabs) and describe various biophysical experiments that could be done in the teaching laboratory using these instruments. In particular, we focus on experiments that image biological materials and quantify biophysical parameters: 1) imaging cells to determine membrane tension, 2) imaging microtubules to determine their persistence length, 3) imaging the random walk of DNA molecules to determine their contour length, and 4) imaging stretched DNA molecules to measure the tensional force.Comment: 29 page preprint, 7 figures, 1 tabl

Migration then assembly: Formation of Neptune mass planets inside 1 AU

We demonstrate that the observed distribution of `Hot Neptune'/`Super-Earth' systems is well reproduced by a model in which planet assembly occurs in situ, with no significant migration post-assembly. This is achieved only if the amount of mass in rocky material is $\sim 50$--$100 M_{\oplus}$ interior to 1 AU. Such a reservoir of material implies that significant radial migration of solid material takes place, and that it occur before the stage of final planet assembly. The model not only reproduces the general distribution of mass versus period, but also the detailed statistics of multiple planet systems in the sample. We furthermore demonstrate that cores of this size are also likely to meet the criterion to gravitationally capture gas from the nebula, although accretion is rapidly limited by the opening of gaps in the gas disk. If the mass growth is limited by this tidal truncation, then the scenario sketched here naturally produces Neptune-mass objects with substantial components of both rock and gas, as is observed. The quantitative expectations of this scenario are that most planets in the `Hot Neptune/Super-Earth' class inhabit multiple-planet systems, with characteristic orbital spacings. The model also provides a natural division into gas-rich (Hot Neptune) and gas-poor (Super-Earth) classes at fixed period. The dividing mass ranges from $\sim 3 M_{\oplus}$ at 10 day orbital periods to $\sim 10 M_{\oplus}$ at 100 day orbital periods. For orbital periods $< 10$ days, the division is less clear because a gas atmosphere may be significantly eroded by stellar radiation.Comment: 41 pages in preprint style, 15 figures, final version accepted to Ap

Antimicrobial Activity of Brassica rapa Nectar Lipid Transfer Protein

Poster presentation at the 2017 Mycological Society of America Annual Meeting.Antimicrobial peptides (AMPs) provide an ancient, innate immunity conserved in all multicellular organisms. In plants, there are several large families of AMPs defined by sequence similarity. The nonspecific lipid transfer protein (LTP) family is defined by a conserved signature of eight cysteines and has a compact structure with a lipid-binding hydrophobic cavity. The antimicrobial activity of LTPs varies greatly among plant species. An LTP from Brassica rapa (variety R-o-18) nectar was tested for antimicrobial activity. In a 96-well microplate, each well contained half strength potato dextrose broth, approximately 2000 spores, and concentrations of LTP peptide up to 300 μg/mL in a total volume of 100 μL. After 48 hours of incubation at 25 C in the dark, absorbance of the wells was measured at 595 nm on a microplate reader to quantify the inhibition of fungal growth. The amount of LTP needed to inhibit growth of pathogen strains by 50% (IC50) was calculated. This Brassica LTP was most effective against Trichoderma and Bipolaris oryzae with IC50 values of 0.78 μM and 1.71 μM, respectively. Additionally, both Colletotrichum trifolii and Alternaria solani had IC50 values of less than 4.0 μM. The activity of this Brassica LTP at such low biological values indicates that it is a potent defense protein. These results suggest that transgenic expression of antimicrobial LTPs has the potential to lead to improved broad-spectrum disease resistanc

Patients' use of a home-based virtual reality system to provide rehabilitation of the upper limb following stroke

Background: A low cost, virtual reality system that translates movements of the hand, fingers and thumb into game play was designed to provide a flexible and motivating approach to increasing adherence to home based rehabilitation. Objective: Effectiveness depends on adherence, so did patients use the intervention to the recommended level. If not, what reasons did they give? Design: Prospective cohort study plus qualitative analysis of interviews. Methods: 17 patients recovering from stroke recruited to the intervention arm of a feasibility trial had the equipment left in their homes for eight weeks and were advised to use it three times a day for periods of no more than 20 minutes. Frequency and duration of use were automatically recorded. At the end of the intervention, participants were interviewed to determine barriers to using it in the recommended way. Results: Duration of use and how many days they used the equipment are presented for the 13 participants who successfully started the intervention. These figures were highly variable and could fall far short of our recommendations. There was a weak (p=0.053) positive correlation between duration and baseline reported activities of daily living. Participants reported familiarity with technology and competing commitments as barriers to use although appreciated the flexibility of the intervention and found it motivating