Iron economy in Arabidopsis thaliana rosettes

2014 Summer.Includes bibliographical references.Iron is important for plant growth and lack of iron negatively affects crop productivity. When we understand more about how plants prioritize their iron use we can use this knowledge to benefit the people of the world. Plant metabolism can be altered to allocate iron in such a way creating larger and/or healthier edible parts. In the first chapter of this thesis I briefly discuss the biological roles of iron and its function in plants with an emphasis on photosynthesis. In the second chapter I investigated the potential prioritization of iron-dependent proteins in Arabidopsis thaliana plants that were grown hydroponically and exposed to one week of iron deprivation followed by one week of iron resupply. Through the one week of iron depletion the treated plants became visually chlorotic and after one week of iron recovery the treated plants appeared to have fully recovered from the chlorosis. At the end of the recovery week treated plants had significantly less biomass than the control plants yet suffered no indirect effects. To investigate if the decrease in biomass was caused by defects in photosynthetic electron transport chlorophyll fluorescence was measured as well as the photooxidation-reduction values of photosystem I (PSI). Indeed photosynthesis was affected and it was found that there was a decrease in electrons flowing to PSI. With the use of immunoblots it was discovered that the cytochrome b6f complex proteins were strongly affected by iron depletion followed by the subunits of PSI. Furthermore, I found that the abundance of sulfur metabolism proteins decreased in reaction to decreased iron nutrition. In the third chapter I discuss the implications of my findings for plant science and society and I give recommendations for follow up work on this project

\u27You Are About to Begin Reading\u27: the Nature and Function of Second Person Point of View in Narrative.

This study asserts that second person point of view functions as a distinct category of point of view, which has been discounted by critical theorists. Second person point of view is defined in this study as a particular use of the second person pronoun. The you in second person point of view texts generates an alternating pattern of identification and displacement that constructs an intersubjectivity among narrative elements--narrator, actant, and narratee(s). Therefore, common uses of the you to refer only to the reader (narratee) of a text or to the actant in a text do not constitute second person point of view texts. The theory of second person point of view developed in this study argues that second person point of view issues challenges to traditional concepts of narrative subjectivity and authority. The rejection of the traditional sign of subjectivity and authority--the stated or implied I --combined with the proposition of an alternative--the multiple you --expresses the particular challenges of second person point of view. The challenges to narrative subjectivity and authority issued by second person point of view indicate the postmodern impulse of second person point of view. By exposing, undermining, and revising traditional concepts of narrative, second person point of view texts participate in the postmodern culture, which seeks to disabuse notions of truth invested in form. The unique challenge of second person point of view to subjectivity participates in contemporary feminist practice as well. Because women have been consigned to the role of nonsubjective other, otherness is of particular interest to feminist theorists and critics. Second person point of view, as defined in this study, constructs a discourse of others in the voice of the multiple you. In this way, second person point of view invests others with the subjectivity denied them by the traditional first person singular fiction of selfhood. . This study proposes continued research of the implications for contemporary literary theory and practice and performance theory and practice offered by second person point of view

Effects of selenium accumulation on reproductive functions in Brassica juncea and Stanleya pinnata

Selenium (Se) is an essential micronutrient for many organisms, but is also a toxin and environmental pollutant at elevated levels. Due to its chemical similarity to sulphur, most plants readily take up and assimilate Se. Se accumulators such as Brassica juncea can accumulate Se between 0.01% and 0.1% of dry weight (DW), and Se hyperaccumulators such as Stanleya pinnata (Brassicaeae) contain between 0.1% and 1.5% DW of Se. While Se accumulation offers the plant a variety of ecological benefits, particularly protection from herbivory, its potential costs are still unexplored. This study examines the effects of plant Se levels on reproductive functions. In B. juncea, Se concentrations >0.05–0.1% caused decreases in biomass, pollen germination, individual seed and total seed weight, number of seeds produced, and seed germination. In S. pinnata there was no negative effect of increased Se concentration on pollen germination. In cross-pollination of B. juncea plants with different Se levels, both the maternal and paternal Se level affected reproduction, but the maternal Se concentration had the most pronounced effect. Interestingly, high-Se maternal plants were most efficiently pollinated by Se-treated paternal plants. These data provide novel insights into the potential reproductive costs of Se accumulation, interactive effects of Se in pollen grains and in the pistil, and the apparent evolution of physiological tolerance mechanisms in hyperaccumulators to avoid reproductive repercussions

Getting to the Root of Selenium Hyperaccumulation—Localization and Speciation of Root Selenium and Its Effects on Nematodes

Elemental hyperaccumulation protects plants from many aboveground herbivores. Little is known about effects of hyperaccumulation on belowground herbivores or their ecological interactions. To examine effects of plant selenium (Se) hyperaccumulation on nematode root herbivory, we investigated spatial distribution and speciation of Se in hyperaccumulator roots using X-ray microprobe analysis, and effects of root Se concentration on root-associated nematode communities. Perennial hyperaccumulators Stanleya pinnata and Astragalus bisulcatus, collected from a natural seleniferous grassland contained 100–1500 mg Se kg−1 root dry weight (DW). Selenium was concentrated in the cortex and epidermis of hyperaccumulator roots, with lower levels in the stele. The accumulated Se consisted of organic (C-Se-C) compounds, indistinguishable from methyl-selenocysteine. The field-collected roots yielded 5–400 nematodes g−1 DW in Baermann funnel extraction, with no correlation between root Se concentration and nematode densities. Even roots containing \u3e 1000 mg Se kg−1 DW yielded herbivorous nematodes. However, greenhouse-grown S. pinnata plants treated with Se had fewer total nematodes than those without Se. Thus, while root Se hyperaccumulation may protect plants from non-specialist herbivorous nematodes, Se-resistant nematode taxa appear to associate with hyperaccumulators in seleniferous habitats, and may utilize high-Se hyperaccumulator roots as food source. These findings give new insight into the ecological implications of plant Se (hyper)accumulation

Rails of War

In a theater of war long forgotten and barely even known at the time, James Harry Hantzis and his fellow soldiers labored at a thankless task under oppressive conditions. Nonetheless, as Rails of War demonstrates, without the men of the 721st Railway Operating Battalion, the Allied forces would have been defeated in the China-Burma-India conflict in World War II.Steven James Hantzis’s father served alongside other GI railroaders in overcoming danger, disease, fire, and monsoons to move the weight of war in the China-Burma-India theater. Torn from their predictable working-class lives, the men of the 721st journeyed fifteen thousand miles to Bengal, India, to do the impossible: build, maintain, and manage seven hundred miles of track through the most inhospitable environment imaginable.From the harrowing adventures of the Flying Tigers and Merrill’s Marauders to detailed descriptions of grueling jungle operations and the Siege of Myitkyina, this is the remarkable story of the extraordinary men of the 721st, who moved an entire army to win the war

Richard Shusterman: somaesthetics

Τhe American pragmatist philosopher Richard Shusterman focuses on soma (body and intellect as inseparate total) working from experience. His main champions are John Dewey and Richard Rorty, both staunch in meliorism; Dewey, on the one hand, with his instrumentalist goals of philosophising and his emphasis on everyday aesthetics and Rorty, on the other hand, with his antifoundationalist views regarding notions as truth or experience and the concurrent, distinguish, powerful role he attributes to language. Soma in Shusterman constitutes the receiver, bearer and processor of aesthetic experience. Having seen that aesthetic experience had been subject of an unprecentant attack in twenty century’s great aestheticians work, Shusterman enriches aesthetic experience with proprioception, mediation and motor-sensοry control. Embodiment is the closer inquiring field of interest for Shusterman. Within this context he proposes Somaesthetics as a particular sub-field of research in Aesthetics. Somaesthetics gathers texts and practices from Epicurus to Zuang Zi and from James to Foucault as much as from Merleau-Ponty to contemporary Embodied Cognitive Science. Much work of Shusterman on somaesthetics refer to its positive role in performance and motor learning and in addition to its constructive assimilation of Feldenkrais method. Shusterman’s radical, eclectic, motley at first sight, mixing of varied aspects and theories of somatic philosophy as long as the expansion of philosophical practice, periodically away from texts and classrooms, into a workout hall, give him a distinct and unique standing in the contemporary perceptual map.O αμερικανός πραγματιστής φιλόσοφος Ρίτσαρντ Σούστερμαν θέτει το σώμα και την εμπειρία στο επίκεντρο της αισθητικής, βελτιόδοξης πρότασής του για το άτομο. Συνεχιστής από τη μία τoυ εργαλειοκρατικού πλαισίου και της αισθητικής εμπειρίας της καθημερινής ζωής του Τζων Ντιούι και από την άλλη άμεσος κληρονόμος των αντιρεαλιστικών αξιώσεων της γλώσσας του Ρίτσαρντ Ρόρτυ, παροχετεύει γόνιμα μια ενεργή, πλουραλιστική, αντιθεμελιοκρατική ως επί το πλείστον φιλοσοφική παράδοση προς την πιο σωματοκεντρική εκδοχή στην ιστορική συνέχειά της. Το έμφορτο συνείδησης, αισθητοποιημένο, ευεπίφορο σε αλλαγές κινητικής συμπεριφοράς, ως νους και κορμί μαζί, αδιαίρετο σώμα (soma) στον Σούστερμαν, αποτελεί υποδοχέα, φορέα και επεξεργαστή της αισθητικής εμπειρίας. Η διαμφισβητούμενη, από πολλούς σύγχρονους φιλοσόφους, αισθητική εμπειρία ενοφθαλμίζεται με διαλογισμό, ιδιοδεκτικότητα, νευρομυϊκό και αισθητηριακό έλεγχο αλλά και με στοιχεία πολιτισμικής θεωρίας επικυρώνοντας το ευρύ, φιλόδοξο πρόγραμμα του Σούστερμαν, τη Σωματαισθητική. Η Σωματαισθητική προτείνεται ως υπο-πεδίο της Αισθητικής και ταυτόχρονα ως χώρος συγκέντρωσης και ανάλυσης θέσεων διαφόρων στοχαστών και ερευνητών για το σώμα που εκτείνονται από τον Επίκουρο έως τον Ζουανγκ Ζι, από τον Τζέημς έως τον Φουκώ και από τις φαινομενολογικές προσεγγίσεις του Μερλώ-Ποντύ έως τη σύγχρονη Σωματοποιημένη Γνωσιακή Επιστήμη (Embodied Cognitive Science). Ωστόσο πλείστα είναι τα παραδείγματα σπουδής και κριτικής που αφορούν την καλλιτεχνική επιτέλεση (performance), το κινησιοθεραπευτικό πρόγραμμα Φελντενκράις (Feldenkrais) και εν γένει τη σωματοποίηση και την κινητική μάθηση. Η εκλεκτικιστική σύμμειξη ετερόκλητων σωματοκεντρικών οπτικών καθώς και η διεύρυνση του πλαισίου άσκησης της φιλοσοφίας εκτός κειμένου διαμορφώνει το ιδιαίτερο στίγμα του Σούστερμαν

How to remove the seasonal atmospheric effect: An application on a surface volcanic temperature at Nisyros active volcano, Hellenic Volcanic Arc

Surface temperature at a volcanic system is the result of a mixture of two heat sources originating one from above and another from below the ground surface. The atmosphere significantly affects the surface's temperature of the volcano, and removal of the atmospheric effect is required for meaningful interpretations prior to any characterization of anomalous volcanic activity. Time series of meteorological data were acquired from the closest weather station to Nisyros volcano, and surface volcanic temperature from the southern part of Nisyros caldera were analyzed. Time series analysis took place at different time scales through a decomposition method. The decomposition of the time series into long-, seasonal-, and short-term components was performed by the application of the Kolmogorov-Zurbenko (KZ) filter to separate the noise that appears on the obtained data. The Time Series Regression (TSR) model was applied in all time scales. The long- and the short-term components of the surface volcanic temperature show no significant correlation with the atmospheric variables, while the seasonal term indicates a very strong association with an R2 equal with 99%. After the removal of the atmospheric effect, our model indicates that there is a normal activity of the seasonal heat emission in Nisyros with no anomalous signals in the temperature residuals during our survey. This methodology may facilitate the process of filtering a seasonal atmospheric effect and better comprehend the heat emission of a volcano-hydrothermal system from temperature surface readings. © 2020 Elsevier B.V

Gas geochemistry and CO2 output estimation of Milos Island (Greece)

Several gas samples have been collected from natural gas manifestations in the island of Milos. Most of them are located underwater along its coasts, whereas three anomalous degassing fumarolic areas (Kalamos, Paleochori and Adamas) were identified on land. Almost all the gases have CO2 as the prevailing gas species, with concentrations ranging from 88 to 99% for the samples taken underwater, while the on-land manifestations present a wider range (15-98%), being sometimes heavily contaminated by air. Methane reaches up to 1.0%, H2 up to 3.2% and H2S up to 3.5% indicating a hydrothermal origin of the gases. The isotope composition of He shows values ranging from 2.55 to 3.39 R/RA, highlighting a significant mantle contribution with the highest values measured at Adamas. C-isotope composition of CO2 is in the range from -1.9 to +1.3\u2030 vs. V-PDB, with most of the values found around -0.5\u2030 indicating a prevailing limestones origin. Isotope composition of CH4, ranging from -18.4 to-5.0\u2030 vs. V-PDB for C and from -295 to +7\u2030 vs. V-SMOW for H, points to a geothermal origin with sometimes evident secondary oxidation processes. CO2-flux measurements showed values up to 1100, 1500 and 8000 g/m2/day in the areas of Kalamos, Paleochori and Adamas respectively and up to about 23,000 g/m2/day in the marine area of Kanava. The south-western part of the island was covered with a lower density prospection, revealing only few anomalous CO2 flux values (up to 650 g/m2/day). Preliminary CO2 output estimations gave values of 1.1, 0.6 and 5.5 tons/day for the three fumarolic areas and of 1.1 tons/day for Kanava. The total output of the island (about 10 tons/day) is comparable to the other volcanic/geothermal systems of the south Aegean active volcanic arc (Nisyros, Kos, Nea Kameni, Methana and Sousaki)

Organs/systems potentially involved in one model of programmed hypertension in sheep

1. When pregnant ewes and their fetuses are exposed to the synthetic glucocorticoid dexamethasone for 2 days early in pregnancy (days 26-28; term 145-150 days), female offspring have increased blood pressure relative to a control group. In one series, this was shown to be due to increased cardiac output, concomitant with a reset mean arterial pressure/heart rate reflex. The first group of such animals had, by the age of 7 years, left ventricular hypertrophy and reduced cardiac functional capacity

Prolonged Low-Dose Dexamethasone, in Early Gestation, Has No Long-Term Deleterious Effect on Normal Ovine Fetuses

Low-dose dexamethasone (D) treatment is used in pregnancies where the fetus is suspected to be at risk of congenital/virilizing adrenal hyperplasia. To study if this treatment had any immediate or long-term effects in normal fetuses, pregnant ewes were treated with D (20 µg/kg maternal body weight·d) or saline (S), from d 25–45 of gestation. Tissue was collected from fetuses killed at 45 d (S = 6; D = 8), 130 d (S = 8; D = 8), or lambs at 2 months of age (S = 6; D = 6) and mRNA levels measured using real-time PCR. D treatment reduced adrenal wt at 45 d (S, 12.2 ± 0.7 mg; D, 6.3 ± 0.4 mg) and significantly decreased adrenal mRNA for P450scc. At 130 d, fetuses from the D treatment were growth retarded (S, 3.2 ± 0.1 kg; D, 2.5 ± 0.1 g), but the adrenals were appropriate for the body weight. mRNA levels of angiotensinogen, the AT1 receptor and mineralocorticoid receptor (MR) and GR were similar in kidney and brain (hypothalamus, hippocampus, medulla oblongata) except for hippocampal expression of MR and GR, which was significantly decreased by D treatment. By 2 months, BW and hippocampal MR and GR mRNA levels were similar, and lambs were normotensive (S, 83 ± 3 mm Hg; D, 78 ± 3 mm Hg). Thus, there were no persistent, long-term effects of prolonged low-dose D treatment in normal ovine fetuses