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The objective of this thesis was to study the response of Eutrema salsugineum (Yukon) plants to low phosphate (Pi) using seedlings and four- week-old plants grown on media formulated with variable phosphate (Pi). Seedlings showed similar root architecture whether grown with high Pi or without added Pi. Four-week-old plants grown with 0 or 2.5 mM Pi added to the soil had the same shoot biomass and relative growth rates. Confirmation that plants on low Pi were Pi-deficient despite lacking a Pi-starvation phenotype was provided by the increased expression of Pi-starvation-inducible genes (notably EsIPS2) in Pi-deprived plants. We also found that seedling roots on media lacking Pi did not acidify their rhizosphere nor did they show increased phosphatase secretion or phosphatase activity relative to roots of Pi-sufficient seedlings. In soil-grown plants, leaf P remobilization was slower during dark-induced senescence of Eutrema relative to similarly treated, Pi-starved Arabidopsis. Also related to metabolism, in vitro assays showed that the ratio of maximal PPi- and ATP- dependent phosphofructokinase activities approximated 1:1 and 2:1 for Eutrema leaf and root extracts, respectively, with no Pi-responsive changes found and, relative to Arabidopsis, Eutrema phosphoenolpyruvate carboxylase activities were high. The enzyme activities suggest Eutrema operates glycolytic by-passes under Pi sufficient and deficient conditions. Finally, transcripts for the transcription factors Phosphate Starvation Response 1 (PHR1) and WRKY75 were not Pi-starvation-inducible and were more abundant in Eutrema leaves than in leaves of Pi-deprived Arabidopsis. Global gene expression showed the leaf and root transcriptomes to be about 90% similar between 0 and 2.5 mM Pi- treated plants with 2,901 differentially expressed genes detected by DESeq2. In summary, Eutrema displays few Pi-starvation responsive traits whether those traits reflect changes at the level of gene expression or plant morphology, behaviour consistent with a specialist that is continuously primed for Pi starvation. / Thesis / Doctor of Philosophy (PhD)

Microorganisms primarily acquire phosphorus (P) in the form of inorganic phosphate (PO4-3 or Pi) through expression of a suite of phosphate scavenging or phosphate transporter systems in response to limiting environmental phosphate. One such system is the Pit family of single protein Pi transport systems found in all domains. These vary in size from 300 to 800 amino acids (a.a.) in size. Previously, the pit gene of the soil bacterium Sinorhizobium meliloti, was found to encode a 334 a.a. Pi uptake system (KM 1-2µM) that is repressed in low Pi conditions. However, the S. meliloti pit gene is encoded in an operon and overlaps the coding sequence of a protein of unknown function, which was denoted as pap (pit-accessory protein). Using a conditional Pi-transport deficient mutant strain of S. meliloti, the effects of pap or pit mutations on Pit-mediated Pi uptake were studied by conducting growth experiments in minimal media (with Pi as the sole source of P) and Pi uptake experiments. Both pap and pit deletions resulted in a loss of growth and Pi uptake, which could be complemented by integration of the pap and pit genes into the deletion locus. Heterologous Pap-Pit systems from Bacteroides thetaiotaomicron and Shewanella oneidensis were found to have KM values (17 and 8.5 µM, respectively) similar to previously reported values of S. meliloti Pap-Pit. However, the Shewanella Pit protein was capable of transporting Pi in the absence of the cognate Pap protein, albeit with greatly reduced velocity at all measured concentrations. Pap-Pit orthologs were identified in ~2000 diverse prokaryotic proteomes using Pfam motifs of Pit (PHO4) and Pap (PhoU_div) protein domains. pap-pit operons were found in a third of all proteomes, and were predicted to be a co-transcribed operon in >95% of cases. This provided additional evidence that Pap is directly involved in Pit-mediated Pi uptake, and also that Pap-Pit systems have a significant role in microbial Pi uptake. Pap protein sequences and structures show striking similarities with that of PhoU, a protein of unknown function implicated as a modulator of the Pst uptake system. Pap and PhoU proteins share highly conserved putative metal-binding motifs (E/DXXXD) of which several Pap missense mutations were found to result in reduced Pi transport. This suggests that like PhoU, Pap may function as a modulator of Pi uptake by an interaction with its cognate transporter, Pit. However, the molecular mechanisms of PhoU and Pap proteins have yet to be defined. / Thesis / Master of Science (MSc) / Microbes acquire and assimilate phosphorus (P) in the form of inorganic phosphate (Pi) through a variety of mechanisms. Pit (Pi transporter) are a family of diverse transporters found in all kingdoms of life. Unlike other Pit systems, the Sinorhizobium meliloti pit gene is encoded in an operon with a protein of unknown function, denoted the pit-accessory protein (pap). Using S. meliloti Pap-Pit and orthologues from other bacteria as model systems, we demonstrate that Pap functions as a positive modulator of Pi uptake via Pit, as Pap is required for active uptake of Pi. Pap-Pit systems are found in 30% of all bacteria and archaea, and thus broadly distributed. Understanding the mechanism of Pap-Pit has biotechnological applications, as multiple Pap-Pit systems are present in phosphorus-accumulating bacteria utilized for waste-water treatment.

A range of techniques designed to monitor copper pitting propensity were applied at two water utilities with known pitting disposition. In addition to traditional approaches including ECorr rise, chlorine decay kinetics, and surface analyses, a novel method was attempted to develop "pitting currents" between copper samples exposed to differential flow. This method allowed pitting current, potential, and resistance between "pits" and sections of copper pipe to be measured. As part of this evaluation, effects of different corrosion inhibitors and secondary disinfectants were investigated in an attempt to identify water quality modifications that might alleviate copper pitting at each utility. At a Florida utility where customers were experiencing a severe pitting problem, experiments investigated the effectiveness of corrosion inhibitors including orthophosphate, an orthophosphate-polyphosphate blend, and zinc polyphosphate. Results suggested that zinc polyphosphate provided the greatest likelihood of mitigating copper pitting corrosion, whereas orthophosphate and the orthophosphate-polyphosphate blend actually increased electrochemical indications of pitting. According to theory, orthophosphates can increase pitting intensity if applied in insufficient quantities, whereas cathodic inhibitors, such as zinc, can only reduce corrosion rates. Surface analyses determined that zinc polyphosphate produced the least amount of scale, whereas the control produced the greatest amount. Further, surface analyses also suggested that zinc and phosphorus may behave synergistically during precipitation reactions which decrease copper release. Subsequent testing at Virginia Tech laboratories confirmed that some of the benefits from the zinc polyphosphate product were directly attributed to zinc. Consistent with previous research, pitting propensity of the water in the absence of inhibitor decreased at pH 7.5 relative to pH 8.5 (Marshall, 2004). In addition, higher concentrations of chloramines increased the pitting propensity of the water, although the ratio of chlorine to ammonia had little effect. Similar experiments were also conducted at a utility in Iowa. Copper pitting has always existed in this area at some low level; however an outbreak of copper pinhole leaks recently occurred that is temporally correlated with high chlorine and chloramine concentrations. Experiments investigated combinations of disinfectant type (free chlorine or chloramines) and corrosion inhibitor (orthophosphate or zinc polyphosphate) in an attempt to decrease pitting propensity. Results indicated that the addition of zinc polyphosphate decreased pitting propensity in free chlorine systems as well as systems dosed with chloramines. In contrast, the addition of orthophosphate seemed to be ineffective in either system. Final surface analyses confirmed that inhibitors performed most effectively in the free chlorine system, whereas no clear benefits were realized in chloramine systems. / Master of Science

Concrete corrosion has serious societal and economic impacts and is an important concern in a utility's overall corrosion control strategy. Though concrete based pipes and linings are only restricted to the distribution mains, they still make up a large percentage of the drinking water infrastructure at about 17% of its total length. An improved understanding of the corrosion mechanisms involved steps that can be taken to mitigate concrete corrosion are very important. This study examined the role of phosphate chemicals, water chemistry, temperature and gaseous cavitation on the degradation of cement-based pipes and linings. It also provides information for utilities to make informed decisions regarding the use, effectiveness, and application of phosphate corrosion inhibitors relative to concrete corrosion control. Under low alkalinity and low pH conditions, considered to be highly aggressive in the literature, we noticed very substantial corrosion of concrete in laboratory experiments. At high pH and high alkalinity conditions, the buildup of scale (e.g., calcium carbonate) on the inside of the pipe is the major concern. The addition of phosphate inhibitors strongly influenced both concrete corrosion and scaling. At low alkalinity the addition of zinc orthophosphate or polyphosphate reduced corrosion of concrete. The addition of orthophosphate under low alkalinity conditions increased aluminum leaching and could push aluminum concentrations above the EPA SMCL threshold. At high alkalinity conditions the addition of orthophosphate is highly effective at reducing scaling, and aluminum leaching was not a concern. The presence of high concentrations of magnesium and silicon could form magnesium aluminum oxyhydroxides and magnesium silicates which could act as a protective scale on the concrete surface. However, this precipitate forms only at pH values above 9.5. The effectiveness of this protective scale in reducing corrosion of concrete was not established unambiguously in this research. Temperature plays a key role in corrosion of concrete. Calcite solubility increases at lower temperatures however at higher temperatures corrosion of concrete increases, which implies that corrosion of concrete is not driven by calcite solubility. At higher alkalinities scaling of concrete is higher at lower temperatures. This indicates that calcite solubility controls scaling of concrete at higher alkalinities. Tests with gaseous cavitation indicate that corrosion of concrete does not increase in the presence of gaseous cavitation. Vaporous cavitation is more detrimental to concrete than gaseous cavitation. / Master of Science

Lewis David Harris. / Typescript. / M.S. Florida State University 1967 / Includes bibliographical references.

A growing population, urbanization and an increase in the number of industries is causing an increase in sewage sludge (SS) that needs to be either beneficially used or disposed of. Application of SS to agricultural lands is a well-known practice but the plant available phosphate and phosphate fertilizer value of SS has been of concern. This is especially due to the wide variety of soils that SS is applied to and the different phosphate removal processes that sewage waste water undergoes at the water care works and the source used to produce SS. Phosphate phyto-availability and phosphate fertilizer value of petrochemical and municipal wastewater sludges (SS) were determined in four different soils using an incubation study over 168 days, a pot trial over 42 days and a field trial over one season. Phosphate phyto-availability was determined/calculated by means of an incubation approach. Soils were incubated with sludge as well as mono ammonium phosphate (MAP). The soils were then subjected to a Bray-1 extraction after a certain time (42 days, 168 days). The relative phosphate fertilizer value (RPFV) was then expressed as a percentage of the Bray-1 extractability of the sludge-amended soil, relative to the MAP-amended soil. The influence of soil properties, especially clay content, and sludge properties namely phosphate extraction method (chemical and biological) from waste water stream, was investigated to determine the effect on phytoavailability and fertilizer value of phosphate in SS-amended soil. Soil properties were the dominant factor determining plant available phosphate, where plant available phosphate decreased with increasing clay content, irrelevant of the type of treatment. There were, however, significant differences between the chemical and biologically removed SS, where the biologically removed SS had higher plant available phosphate. The RPFV % of the SS was comparable to MAP in terms of its plant availability. Wetting and drying cycles in the pot trial influenced the plant available phosphate from the SS, where the chemically treated sludge showed in general lower plant availability. The RPFV % of the biologically removed phosphate sludges was better than that of MAP and that of the chemically phosphate removed sludge were lower. Application of all the different sludge types resulted in a positive reaction on plant available phosphate for all the soils. All the trials were conducted at pH of about 5.5. However, it is expected that biologically P removed sludge will perform better in acid soils. The reason being that ferric phosphate in the chemically treated sludge is less soluble under pH conditions lower than 5.5 than above it. / Dissertation (MScAgric)--University of Pretoria, 2014. / tm2015 / Plant Production and Soil Science / MScAgric / Unrestricted

Phosphorus (P) is one of the three major macronutrients that plants need to grow and survive. When P is scarce, plants utilize a network of characterized responses known as the Phosphate Starvation Response (PSR) to remobilize internal stores of P as well as external P from soil. Emerging evidence shows the PSR is regulated by a specialized group of secondary messenger molecules, inositol pyrophosphates (PP-InsP). PP-InsPs and their precursors, inositol phosphates (InsPs), are important for plant abiotic stress responses, hormone signaling, and other stress responses. While PP-InsPs are critical for plant survival, much about the roles of PP-InsPs and how they are regulated remains to be understood. Further, the enzymes responsible for the synthesis of PP-InsPs in plants have been recently discovered; however, not much is known about the enzymes that degrade PP-InsPs in plants. The goal of the work presented herein is to understand critical aspects of the PP-InsP signaling in plants and leverage this information into a P phytoremediation strategy. To achieve this, I have investigated a group of PP-InsP phosphatases and assessed long-term impacts of depleting PP-InsPs in two plant species, Arabidopsis thaliana (Arabidopsis) and Thlaspi arvense (Pennycress). Exploring the impact of plant PP-InsP phosphatases has allowed me to explore critical aspects of PP-InsP sensing that show great promise for informing P remediation strategies. / Doctor of Philosophy / The Phosphorus (P) crisis presents a major challenge to food security. While Phosphorus (P) is critical for crop growth, P is a nonrenewable and increasingly limited resource. Our global population is fed at the expense of the remaining mineable P reserve, which may be depleted in as early as 30 years. Further, fertilizer runoff from farmland and urban areas poses a dangerous problem as increased nutrients in watersheds toxifies our water supply and aquatic ecosystems. Time is running out to preserve our P supply. New and innovative strategies that reduce fertilizer inputs and watershed pollution are key to securing the global food supply and protecting the environment. Emerging evidence shows plants sense and respond to P using signaling molecules known as inositol pyrophosphates (PP-InsPs). My work and that of others are key in showing that alteration of the levels of PP-InsPs can decrease plant P dependency or cause plants to hyperaccumulate P. Understanding how plants are able to sense, respond, and acquire P is crucial to inform future P phytoremediation strategies to secure global food security.

Orientador: Fernando Galembeck / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-11T05:04:46Z (GMT). No. of bitstreams: 1 Santos_ElviraAparecidaSanchesBizarrodos_M.pdf: 2512802 bytes, checksum: a596de5adfd14b56a92761fc413530c8 (MD5) Previous issue date: 2007 / Resumo: O uso de alquilosfatos é bastante conhecido como emulsionantes em cosméticos. Assim como os alquilfosfatos , os compostos fosf atados derivados de surfactantes não iônicos também são bastante utilizados. Especialmente no setor cosmético, os alquilfosfatados são largamente utilizados devido sua característica de suavidade à pele e aos cabelos. O trabalho teve por objetivo a obtenção e caracterização da glicerina etoxilada fosfatada. Durante a etapa de obtenção optou- se por utilizar dois agentes fosf atantes largamente utilizados na obtenção de alquilfosfatos: pentóxido de fósforo e ácido polifosfórico. Na etapa de caracterização, utilizou- se técnicas de espect roscopia de infravermelho e de emissão atômica, cromatografia de troca iônica, espect roscopia de ressonância magnética nuclear , espectrometria de massas e potenciometria. Foi possível determinar o rendimento da fosfatação, assim como identificar a presença de monoéster e ácido fosfórico em todas as amostras geradas . Diferente do que foi encontrado na literatura consultada, verificou-se que para glicerina etoxilada fosfatada, não existe a formação de quantidades equimolares de monoés ter e diés ter quando ut i l i zado o pentóxido de fósforo como agente fosfatante, e que o ácido polifosfórico leva a um maior rendimento da fosfatação quando utilizada a relação molar 1:1, glicerina etoxilada: PPA. Durante a caracterização foi avaliado o comportamento das amostras em solução aquosa em diferentes valores de pH, e concluiu- se que a glicerina etoxi lada fosfatada não é um composto surfactante, pois não é capaz de reduzir a tensão superficial da água abaixo de 45mN/m quando solubi l i zada a 0,50% (m/m) , o que justifica sua incapacidade de f ormar espuma. O t rabalho sugere algumas aplicações para glicerina etoxi lada fosfatada com base nas informações encontradas na literatura para álcoois graxos etoxilados fosfatados / Abstract: The use of al kylphosphate is widely known as emulsifier in cosmetics. As alkylphosphates , the phosphated compounds derived from non-ionic surfactants are widely used in skin care products. Especially in cosmetic area, the alkylphosphates are used because their softness to skin and hair. The main goal of this work was the phosphorylation and characterization of glycer in ethoxylated phosphate. During the phosphorylation' s step two phosphorylating agents were chosen, those are commonly used in alkylphosphate process: phosphorus pentoxide and polyphosphoric acid (PPA). Throughout characterization's step infrared spectroscopy, atomic emission spectroscopy, exchange ion chromatography, nuclear magnetic resonance, mass spectroscopy and potentiometric titration were used. It was possible to determine the grade of process conversion as to identify the presence of monoester in all obtained samples. The result found in the phosphorylation process was different from those in the literature, because a ratio equimolar between monoester and diester was not found when phosphorus pentoxide was used as phosphorylating agent, and the use of polyphosphoric acid leads to a higher grade of conversion when the relation 1:1 for glycer in: PPA is used. During the characterization, the phosphated samples in water solution's behavior was evaluated in many values of pH, and it was possible to conclude that the glycerin poly(ethyleneoxi ) phosphate is not a surfactant, because it is unable to reduce the superficial tension of water under 45mN/m when solubilized at 0,50% (m/m), what can justify its inability to form foam. The work suggest s some applications to the glycerin poly(ethyleneoxi) phosphate according the informat ion that was found in the literature / Mestrado / Físico-Química / Mestre em Química