High Phosphate Concentrations Research Articles

Drivers of bacterial diversity along a natural transect from freshwater to saline subtropical wetlands

Tropical coastal wetlands provide a range of ecosystem services that are closely associated with microbially-driven biogeochemical processes. Knowledge of the main players and their drivers in those processes can have huge implications on the carbon and nutrient fluxes in wetland soils, and thus on the ecosystems services we derive from them. Here, we collected surface (0–5 cm) and subsurface (20–25 cm) soil samples along a transect from forested freshwater wetlands, to saltmarsh, and mangroves. For each sample, we measured a range of abiotic properties and characterised the diversity of bacterial communities using 16S rRNA gene amplicon sequencing. The alpha diversity of bacterial communities in mangroves exceeded that of freshwater wetlands, which were dominated by members of the Acidobacteria, Alphaproteobacteria and Verrucomicrobia, and associated with high soil pore-water concentrations of soluble reactive phosphorous, and nitrogen as nitrate and nitrite (N-NOX−). Bacterial communities in the saltmarsh were strongly stratified by depth and included members of the Actinobacteria, Chloroflexi, and Deltaproteobacteria. Finally, the mangroves were dominated by representatives of Deltaproteobacteria, mainly Desulfobacteraceae and Synthrophobacteraceae, and were associated with high salinity and soil pore-water concentrations of ammonium (N-NH4+). These communities suggest methane consumption in freshwater wetlands, and sulfate reduction in deep soils of marshes and in mangroves. Our work contributes to the important goal of describing reference conditions for specific wetlands in terms of both bacterial communities and their drivers. This information may be used to monitor change and assess wetland health and function.

Molecular Binding of EuIII/CmIII by Stenotrophomonas bentonitica and Its Impact on the Safety of Future Geodisposal of Radioactive Waste.

Microbial communities occurring in reference materials for artificial barriers (e.g., bentonites) in future deep geological repositories of radioactive waste can influence the migration behavior of radionuclides such as curium (CmIII). This study investigates the molecular interactions between CmIII and its inactive analogue europium (EuIII) with the indigenous bentonite bacterium Stenotrophomonas bentonitica at environmentally relevant concentrations. Potentiometric studies showed a remarkably high concentration of phosphates at the bacterial cell wall compared to other bacteria, revealing the great potential of S. bentonitica for metal binding. Infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed the role of phosphates and carboxylate groups from the cell envelope in the bioassociation of EuIII. Additionally, time-resolved laser-induced fluorescence spectroscopy (TRLFS) identified phosphoryl and carboxyl groups from bacterial envelopes, among other released complexing agents, to be involved in the EuIII and CmIII coordination. The ability of this bacterium to form a biofilm at the surface of bentonites allows them to immobilize trivalent lanthanide and actinides in the environment.

P/Ca in Carbonates as a Proxy for Alkalinity and Phosphate Levels

AbstractUnderstanding mechanisms, rates, and drivers of past carbonate formation provides insight into the chemical evolution of Earth's oceans and atmosphere. We paired geological observations with elemental and isotope geochemistry to test potential proxies for calcium‐to‐alkalinity ratios (Ca:ALK). Across diverse carbonate facies from Pleistocene closed‐basin lakes in Owens Valley, CA, we observed less δ44/40Ca variation than theoretically predicted (>0.75‰) for the very low Ca:ALK in these systems. Carbonate clumped isotope disequilibria implied rapid carbonate growth—kinetic isotope effects, combined with the diverse carbonate minerals present, complicated the interpretation of δ44/40Ca as a paleoalkalinity proxy. In contrast, we observed that the high phosphate concentrations are recorded by shoreline and lake bottom carbonates formed in 11 Pleistocene lakes at orders of magnitude greater concentrations than in marine carbonates. Because the maximum phosphate content of water depends on Ca:ALK, we propose that carbonate P/Ca can inform phosphate levels and thereby Ca:ALK of aqueous environments in the carbonate record.

Clay mineralogy and micropedology of phosphate-rich soils from Lions Rump, Maritime Antarctica

Micropedology studies by description of scanning electron microscopy images and electron micropobre analysis combined with field soil description, mineralogical, physical, and chemical laboratory analyses, can furnish valuable information about soil genesis in polar regions. The present study was carried out at Lions Rump (King George Island, Maritime Antarctica), where six pedons were selected to represent the main soil types found in the local ice-free areas, varying from bare (without vegetation) to well-vegetated ornithogenic soils, with high phosphate and organic matter content. Each pedon was described and sampled for mineralogical, micromorphological and microchemical studies, complemented by chemical and physical analyses. Phosphatization is the main forming process in these soils and two types of ornithogenic soils could be distinguished: Acid pH ornithogenic soils and Neutral pH ornithogenic soils. Phosphate-rich, deep, acid pH ornithogenic soils are the most developed soils and occur associated with abandoned penguin rookeries, with well-crystalline Al-phosphates (taranakite). Soils recently occupied by penguins have neutral pH and absence of crystalline phosphate minerals, although they are also rich in exchangeable P. Phosphate are found as illuvial coatings, infillings, reacting alteration cortex of clasts or compound the micromass of the aggregates. Although the microstructures of Lions Rump soils are related to frost-action, the phosphatization forming a particular well-developed rounded aggregates, under strong biological influence. The ornithogenesis depends on the time of exposure to birds' influence and decomposition stage of guano.

Engineering of the spin on dopant process on silicon on insulator substrate

We report on a systematic analysis of phosphorus diffusion in silicon on insulator thin film via spin-on-dopant process (SOD). This method is used to provide an impurity source for semiconductor junction fabrication. The dopant is first spread into the substrate via SOD and then diffused by a rapid thermal annealing process. The dopant concentration and electron mobility were characterized at room and low temperature by four-probe and Hall bar electrical measurements. Time-of-flight-secondary ion mass spectroscopy was performed to estimate the diffusion profile of phosphorus for different annealing treatments. We find that a high phosphorous concentration (greater than 1020 atoms cm−3) with a limited diffusion of other chemical species and allowing to tune the electrical properties via annealing at high temperature for short time. The ease of implementation of the process, the low cost of the technique, the possibility to dope selectively and the uniform doping manufactured with statistical process control show that the methodology applied is very promising as an alternative to the conventional doping methods for the implementation of optoelectronic devices.

Photosynthetic performance and stevioside concentration are improved by the arbuscular mycorrhizal symbiosis in Stevia rebaudiana under different phosphate concentrations.

In plants, phosphorus (P) uptake occurs via arbuscular mycorrhizal (AM) symbiosis and through plant roots. The phosphate concentration is known to affect colonization by AM fungi, and the effect depends on the plant species. Stevia rebaudiana plants are valuable sources of sweetener compounds called steviol glycosides (SGs), and the principal components of SGs are stevioside and rebaudioside A. However, a detailed analysis describing the effect of the phosphate concentration on the colonization of AM fungi in the roots and the relationship of these factors to the accumulation of SGs and photochemical performance has not been performed; such an analysis was the aim of this study. The results indicated that low phosphate concentrations (20 and 200 µM KH2PO4) induced a high percentage of colonization by Rhizophagus irregularis in the roots of S. rebaudiana, while high phosphate concentrations (500 and 1,000 µM KH2PO4) reduced colonization. The morphology of the colonization structure is a typical Arum-type mycorrhiza, and a mycorrhiza-specific phosphate transporter was identified. Colonization with low phosphate concentrations improved plant growth, chlorophyll and carotenoid concentration, and photochemical performance. The transcription of the genes that encode kaurene oxidase and glucosyltransferase (UGT74G1) was upregulated in colonized plants at 200 µM KH2PO4, which was consistent with the observed patterns of stevioside accumulation. In contrast, at 200 µM KH2PO4, the transcription of UGT76G1 and the accumulation of rebaudioside A were higher in noncolonized plants than in colonized plants. These results indicate that a low phosphate concentration improves mycorrhizal colonization and modulates the stevioside and rebaudioside A concentration by regulating the transcription of the genes that encode kaurene oxidase and glucosyltransferases, which are involved in stevioside and rebaudioside A synthesis in S. rebaudiana.

Removal of As (V) in water using β-Cyclodextrin intercalated Fe-Al layered double hydroxide/reduced Graphene Oxide nanocomposites

Highly effective nanoadsorbent based on β-Cyclodextrin intercalated Fe-Al layered double hydroxide/reduced Graphene Oxide (FAH-rGO/CD) nanocomposites were synthesized through hydrothermal and ex-situ polymerization process for As (V) adsorption in wastewater. Characterization results of XRD, FESEM and HRTEM reveals the crystalline structure and morphology of the FAH-rGO/CD nanocomposites. The elemental composition and functional groups of the composites were investigated by EDS and FTIR. N2 adsorption-desorption analysis was utilized to determine the surface area of the prepared nanocomposite and the incorporated β-CD moieties enhances the surface area of FAH-rGO (145.35 m2g−1). Various adsorption parameters of nanoadsorbents such as the effect of pH, contact time, adsorbent dosage, adsorption isotherms and kinetics were studied and reported. The obtained adsorption isotherm data of synthesized adsorbent was properly fitted with Langmuir isotherm model along with their maximum monolayer adsorption capacity of 185.52 mg g−1 for As (V). The Pseudo-first and second kinetic models were used to assess the kinetic data and the adsorption of As (V) pursued the Pseudo second order model with high correlation co-efficient R2 value (0.9836). Moreover, as-synthesized adsorbents had good recyclability up to 89%, even after five adsorption-desorption analysis. Meanwhile, the presence of co-existing anions on sorption of As (V) was evaluated and their results indicate that, the high concentration of phosphate and carbonate ions inhibited the efficiency of As (V) removal. Thus, high surface area with abundant oxygen containing hydroxyl groups and magnetic properties of FAH-rGO/CD nanocomposites proved to be highly effective adsorbent for As (V) removal in wastewater.

Living phosphatic stromatolites in a low-phosphorus environment: Implications for the use of phosphorus as a proxy for phosphate levels in paleo-systems.

In the geological record, fossil phosphatic stromatolites date back to the Great Oxidation Event in the Paleoproterozoic, but living phosphatic stromatolites have not been described previously. Here, we report on cyanobacterial stromatolites in a supratidal freshwater environment at Cape Recife, South African southern coast, precipitating Ca carbonate alternating with episodes of Ca phosphate deposition. In their structure and composition, the living stromatolites from Cape Recife closely resemble their fossilized analogues, showing phosphatic zonation, microbial casts, tunnel structures and phosphatic crusts of biogenic origin. The microbial communities appear to be also similar to those proposed to have formed fossil phosphatic stromatolites. Phosphatic domains in the material from Cape Recife are spatially and texturally associated with carbonate precipitates, but form distinct entities separated by sharp boundaries. Electron Probe Micro-Analysis shows that Ca/P ratios and the overall chemical compositions of phosphatic precipitates are in the range of octacalcium phosphate, amorphous tricalcium phosphate and apatite. The coincidence in time of the emergence of phosphatic stromatolites in the fossil record with a major episode of atmospheric oxidation led to the assumption that at times of increased oxygen release the underlying increased biological production may have been linked to elevated phosphorus availability. The stromatolites at Cape Recife, however, form in an environment where ambient phosphorus concentrations do not exceed 0.28μM, one to two orders of magnitude below the previously predicted minimum threshold of >5μM for biogenic phosphate precipitation in paleo-systems. Accordingly, we contest the previously proposed suitability of phosphatic stromatolites as a proxy for high ambient phosphate concentrations in supratidal to shallow ocean settings in earth history.

Effect of Azospirillum zeae and Seed Priming with Zinc, Manganese and Auxin on Growth and Yield Parameters of Wheat, under Dryland Farming

In this study, field experiments with wheat (Triticum aestivum L.) were conducted consecutively for 2 years. The main objective was to determine (1) effect of seed priming with auxin (IAA), zinc (Zn) or manganese (Mn) on growth and yield parameters of wheat under dry land farming; (2) influence of on-farm priming with Azospirillum under field conditions. In this study, the response of dryland wheat yield to soaking seeds in water, 2 ppm IAA, 0.2% Mn solution and 0.2% aqueous solution of Zn with or without Azospirillum zeae inoculation was investigated under field condition. Total grain yield was significantly enhanced for water primed seeds i.e., 1273 kg ha−1 (6.8%) or seeds primed with IAA, as compared to 1191 kg ha−1 in plants from non-primed seeds. Difference in grain yield between priming with water and 2 ppm IAA was not significant when compared with 1372 kg ha−1 (15%) for seeds primed with 0.2% Mn solution and 1440 kg ha−1 (20%) for seeds primed with 0.2% Zn solution. Grain yield was significantly increased for plants inoculated with Azospirillum, 1411 kg ha−1 (8%) as compared to 1191 t ha−1 for non-Azospirillum-inoculated seeds. Yield parameters, i.e., tiller no. per m−2, grain number per spike, and 1000-grain weight, were all significantly affected by priming treatments and Azospirillum inoculation. Grains with the high nitrogen and phosphorous content were recorded for the treatment where seeds were primed with Zn and inoculated with Azospirillum. In the present study, inoculation of wheat seeds followed by priming is a significant approach to enhance grain yield and grain nutrients (N and P) content.

Chemical, physical, and sensory attributes of Sauvignon blanc wine fermented in different kinds of vessels

The use of vessels that are alternative to conventional cylindrical stainless steel tanks and traditional oak barrels during winemaking has increased in recent years. Examples of these alternative vessels include fashionable, oval-shaped vessels or classic clay jars. A Sauvignon blanc grape juice was fermented (by using a commercial starter made of two different commercial strains from Oenobrands/Anchor Oenology) in four different vessels in triplicate: 150 L cylindrical stainless steel tanks (as a control), 980 L polyethylene oval-shaped tanks, 450 L concrete oval-shaped tanks, and 225 L clay jars. Afterwards, the finished wines were chemically, physically, and sensorially characterized. The wine fermented in the concrete vessels had a slightly higher pH (about 0.05 pH units) and lower titratable acidity (about 0.20 g/L of tartaric acid equivalents) value than those of the control wine. The wine fermented in the clay jars showed the lowest amounts of C10, C12, and C14 volatile compounds (containing about 69% of those compounds when compared with the control wine). The wine fermented in the polyethylene oval-shaped tanks was described as the most bitter, while the wine fermented in the concrete oval-shaped tanks was described as the least fruity when wines were sensory analyzed by a panel of 11 wine experts. The wines fermented in the oval-shaped vessels showed lower volatile acidity (about 25% reduction of volatile acidity when compared with wines fermented in non-oval-shaped vessels), higher residual sugars (wines fermented in the oval-shaped vessels contained about 1.7 g/L of residual sugars, while wines fermented in the non-oval-shaped vessels contained about 1.4 g/L of residual sugars), higher phosphorous content (with an increase of about 12%), and required a lower dose of bentonite to achieve protein stability (about 64 g/hL of bentonite) than those of the other wines (about 75 g/hL of bentonite). Even though some statistical differences were found among wines fermented in the different vessels, it should be noted that the differences were very small. Thus, it seems that the impact of the fermentation vessel type on final wine features is lower than expected.

Inorganic Phosphate (Pi) Signaling in Endothelial Cells: A Molecular Basis for Generation of Endothelial Microvesicles in Uraemic Cardiovascular Disease.

Hyperphosphataemia increases cardiovascular mortality in patients with kidney disease. Direct effects of high inorganic phosphate (Pi) concentrations have previously been demonstrated on endothelial cells (ECs), including generation of procoagulant endothelial microvesicles (MVs). However, no mechanism directly sensing elevated intracellular Pi has ever been described in mammalian cells. Here, we investigated the hypothesis that direct inhibition by Pi of the phosphoprotein phosphatase PP2A fulfils this sensing role in ECs, culminating in cytoskeleton disruption and MV generation. ECs were treated with control (1 mM [Pi]) vs. high (2.5 mM [Pi]), a condition that drives actin stress fibre depletion and MV generation demonstrated by confocal microscopy of F-actin and NanoSight Nanoparticle tracking, respectively. Immuno-blotting demonstrated that high Pi increased p-Src, p-PP2A-C and p-DAPK-1 and decreased p-TPM-3. Pi at 100 μM directly inhibited PP2A catalytic activity. Inhibition of PP2A enhanced inhibitory phosphorylation of DAPK-1, leading to hypophosphorylation of Tropomyosin-3 at S284 and MV generation. p-Src is known to perform inhibitory phosphorylation on DAPK-1 but also on PP2A-C. However, PP2A-C can itself dephosphorylate (and therefore inhibit) p-Src. The direct inhibition of PP2A-C by Pi is, therefore, amplified by the feedback loop between PP2A-C and p-Src, resulting in further PP2A-C inhibition. These data demonstrated that PP2A/Src acts as a potent sensor and amplifier of Pi signals which can further signal through DAPK-1/Tropomyosin-3 to generate cytoskeleton disruption and generation of potentially pathological MVs.

Environmental determinants of plant associations and evaluation of the conservation status of Parrotiopsis jacquemontiana in Dir, the Hindu Kush Range of Mountains

Hindu Kush is the largest mountain range of Central Asia that forms part of a vast alpine zone that stretches across the Eurasia from east towards the South Asia. We studied vegetation structure and the role of edaphic and topographic factors on distribution and formation of plant associations with specific emphais on Parrotiopsis species of the Districts Dir regions in the Hindu Kush Mountains. We also assessed the conservation status of Parrotiopsis jacquemontiana, an endemic species of the western Himalayan floristic province. We hypothesized that edaphic and climatic factors were responsible for the formation of different plant associations each with distinct indicators. A combination of transect and quadrat based methods were used for sampling. We used two way cluster analysis (TWCA), cluster analysis (CA), indicator species analysis, detrended correspondence analysis and canonical correspondence analysis to analyze and elaborate the vegetation pattern and formation. We used Google Earth Path software (V 1.4.6) for the calculation of extant of occurrence (EOO) and area of occupancy (AOO) for evaluation of conservation status of P. jacquemontiana. A total of 142 plant species were reported belonging to 62 families. CA and TWCA clustered four plant associations within altitudinal range of 1556–2313 m. Parrotiopsis jacquemontiana should be designated as endangered species under ‘EN A2acd; B1B2 bc (i, ii, iii) of IUCN red list categories and criteria in the region. We found that high phosphorous and potassium concentration, elevation, aspect, slope, lower pH, electrical conductivity and soil texture were significant environmental variables that play an important role in the determination of vegetation structure, formation of plant associations and its indicators in the region. This information will be useful for conservation and management practices for endemic and rare plant taxa, and evaluation of vegetation structure.

REMOVAL OF PO43- BY DIRECT CONTACT MEMBRANE DISTILLATION FROM DAIRY WASTEWATER

The dairy industry is one of the basic industries that are important for the sustainability of life and because this industry uses and consumes a lot of water to produce milk, it discharges a lot of waste water. Because of the acute shortage of water needed to meet domestic, industrial and agricultural needs and increase pollution on the other, and of high fresh water demand in recent years, therefore; treatment of wastewater present very important. The most important pollutants of dairy wastewater discharged are phosphate. The present paper offers an ability of membrane distillation process (MD) for the treatment of dairy wastewater and removal of phosphate in Iraq. Artificial samples of wastewater prepared to implement the proposal. Opinions will be considered to make these wastewater samples within the standard properties of world dairy wastewater classifications. To alleviate membrane disturbances by organic and inorganic substances applied to physical deposition. The results showed the ability of the MD to remove a high concentration of phosphate from wastewater from dairy wastewater, with a clearance rate of 95 per cent. This value affected by temperature and temperature affects the effectiveness of The MD and is directly proportional to the flow.

Competitive Interaction of Phosphate with Selected Toxic Metals Ions in the Adsorption from Effluent of Sewage Sludge by Iron/Alginate Beads.

Wastewater is characterized by a high content of phosphate and toxic metals. Many studies have confirmed the sorption affinity of alginate adsorbents for these ions. In this study, the adsorption of phosphate from effluent of sewage sludge on biodegradable alginate matrices cross-linked with Fe3+ ions (Fe_Alg) was investigated. Kinetics and adsorption isotherms were tested in laboratory conditions in deionized water (DW_P) and in the effluent (SW_P), and in the same solutions enriched in toxic metals ions—Cu2+, Cd2+, Pb2+, and Zn2+ (DW_PM and SW_PM). Batch experiments were performed by changing the concentration of phosphate at constant metal concentration. Kinetics experiments indicated that the pseudo-second-order model displayed the best correlation with adsorption kinetics data for both metals and phosphate. The Freundlich equation provided the best fit with the experimental results of phosphate adsorption from DW_P and DW_PM, while the adsorption from SD_P and SD_PM was better described by the Langmuir equation. For tested systems, the affinity of the Fe_Alg for metal ions was in the following decreasing order: Pb2+ > Cu2+ > Cd2+ > Zn2+ in DW_PM, and Pb2+ > Cu2+ > Cd2+ > Zn2+ in SW_PM. The metals’ enrichment of the DW_P solution increased the affinity of Fe_Alg beads relating to phosphate, while the addition of the metals of the SW_P solution decreased this affinity.

Differential Evolution of α-Glucan Water Dikinase (GWD) in Plants.

The alpha-glucan water dikinase (GWD) enzyme catalyzes starch phosphorylation, an integral step in transitory starch degradation. The high phosphate content in stored starch has great industrial value, due to its physio–chemical properties making it more versatile, although the phosphate content of stored starch varies depending on the botanical source. In this study, we used various computational approaches to gain insights into the evolution of the GWD protein in 48 plant species with possible roles in enzyme function and alteration of phosphate content in their stored starch. Our analyses identified deleterious mutations, particularly in the highly conserved 5 aromatic amino acid residues in the dual tandem carbohydrate binding modules (CBM-45) of GWD protein in C. zofingiensis, G. hirsutum, A. protothecoides, P. miliaceum, and C. reinhardtii. These findings will inform experimental designs for simultaneous repression of genes coding for GWD and the predicted interacting proteins to elucidate the role this enzyme plays in starch degradation. Our results reveal significant diversity in the evolution of GWD enzyme across plant species, which may be evolutionarily advantageous according to the varying needs for phosphorylated stored starch between plants and environments.

The effect of SiO2 on phosphate and ammonium recovery from fertilizer wastewater

Phosphate and ammonium recovery from wastewater could produce magnesium ammonium phosphate (MAP). Several previous studies have found that precursor ions have an impact on MAP formation, such as the presence of calcium, sulfate, fluoride, and other ions. The wastewater from the petrochemical industry that mainly produces fertilizer contains a high concentration of ammonium, phosphate, and silica. This study aims to determine the effect of silica on MAP precipitation. The batch system used a jar test at an optimum speed of 158 rpm for 60 min. MgCl2 was used as a precipitation agent. Synthetic wastewater with a [Mg]/[NH4–N]/[PO4] and [SiO2] ratio was predicted using the PHREEQC model. The pH variations of the sample were 8, 8.5, and 9. SiO2 concentration varied in the range of 20–1000 mg/L. The parameters measured were pH, silica, phosphate, ammonium, and magnesium concentration, and MAP morphology. MAP precipitation has an impact on increasing the concentration of silica in wastewater. Recovery of phosphate and ammonium reduction reached 20% and 10%, respectively, with the concentration of silica of 1000 mg/L at pH 9 ± 0.2. The morphology of MAP as analyzed by SEM and XRD shows that silica has an impact on the purity of the MAP.

Roles of defects and linker exchange in phosphate adsorption on UiO-66 type metal organic frameworks: Influence of phosphate concentration

Recently, UiO-66 type metal organic frameworks (MOFs) have been studied as adsorbents for phosphate removal from wastewater; however, the adsorption mechanism with different concentrations of phosphate, especially the roles of defects and linker exchange, are not entirely clear. In this work, the phosphate adsorption mechanism in HCl-UiO-66 and HCl-NH2-UiO-66 were examined by testing the relationship between the adsorbed phosphate and released linker in the adsorption process. Adsorption kinetics studies (3.0 mM phosphate solution) and adsorption isotherm analyses (0.3–6.0 mM phosphate solution) revealed highly linear relationships (R2 = 0.8949–0.9978) between the adsorbed phosphate and released linker for both adsorbents. Further analysis showed that when the adsorbed phosphate was lower than 0.56 mmol/g for HCl-UiO-66 and 0.51 mmol/g for HCl-NH2-UiO-66, phosphate was preferentially adsorbed on the defect sites in the MOFs with no linker release. However, when the adsorbed phosphate exceeded these levels, the defects were saturated by phosphate and linker exchange became the major adsorption mechanism. Based on density functional theory calculations, the obtained strengths of the linkers (H2BDC: Terephthalic acid; NH2-H2BDC: 2-Aminoterephthalic Acid; NO2-H2BDC: 2-Nitroterephthalic Acid) and phosphate species as Lewis bases fall in the order, PO43- > HPO42- > NH2-BDC2- > BDC2- > H2PO4- > NO2-BDC2- > H3PO4, which clearly evidences why linkers can be exchanged by phosphate. Given the propensity for ligand exchange and the resulting structural destabilization, UiO-66 type MOFs is not suggested as ideal adsorbents for phosphate removal from wastewater with high phosphate concentrations.

The PHO pathway regulates white-opaque switching and sexual mating in the human fungal pathogen Candida albicans.

The opportunistic fungal pathogen Candida albicans is able to switch among several morphological phenotypes in response to environmental changes. White-opaque transition is a typical phenotypic switching system involved in the regulation of pathogenesis and sexual reproduction in C. albicans. Under regular laboratory culture conditions, to undergo white-to-opaque switching, cells must first undergo homozygosis at the mating-type locus (MTLa/a or α/α) since the a1/α2 heterodimer represses the expression of the Wor1 master regulator of switching in MTLa/α heterozygous strains. In this study, we report the roles of the PHO pathway of phosphate metabolism in the regulation of white-opaque switching and sexual mating in C. albicans. We find that deletion of the PHO pathway genes PHO81, PHO80, PHO2, and PHO4 induces the opaque phenotype in MTLa/α heterozygous cells. Low concentrations of external phosphate are conducive for the opaque phenotype in both MTL homozygous and heterozygous strains. Moreover, phosphate starvation can also increase the mating efficiency in C. albicans. Consistently, the pho80/pho80 mutant mimics an artificial phosphate starvation state and mates efficiently at both lower and higher phosphate concentrations. Our study establishes a link between the PHO pathway and white-opaque epigenetic switching in C. albicans.

Co-Pyrolysis of Rice Husk and Chicken Manure

Abstract The increase in the production scale of chicken causes an increment in the produced manure. Chicken manure is considered an excellent soil amendment due to the high nitrogen and phosphorous content. However, the high production of manure exceeds the soil requirements. Rice husk is a by-product of rice production. Approximately one hundred forty million tons of rice husk is produced per year worldwide. There are several ways to manage rice husk such as animal bedding, direct combustion, or as a soil fertilizer. The husk's ashes are suitable for construction or as reinforcing material due to the high silica content. However, rice husk has a low volatile matter and high silica content, which makes processes like direct combustion inefficient. Thermochemical processes (such as pyrolysis and gasification) are effective ways to manage waste. The present study investigates the co-pyrolysis of chicken manure and rice husk. The experiments were conducted in a non-isothermal gravimetrical analyzer using nitrogen at a flowrate of 100 ml/min at three different heating rates (5, 10, and 15 °C/min). The degradation of individual biomass and biomass blends is investigated. The kinetic parameters are calculated using the Friedman method. Results show a positive synergetic effect for mixing ratios greater than 20% rice husk. The mixing ratio of 40% of rice husk manifested the best performance among all blends. This mixture showed the minimum energy of activation (90.2 kJ/mol). Also, the 40% rice husk mixing ratio showed maximum conversion when compared with chicken manure's conversion.

Simple and efficient method to synthesize ferric oxyhydroxide nanoparticles on carbon fiber fabric for environmental application

In this study, we report for the first time a simple one step synthesis of ferric oxyhydroxide nanoparticles (NPs) on carbon fiber (CF) fabric using thermal hydrolysis method. It is the first report wherein spindle-shaped ferric oxyhydroxide NPs were obtained on CF fabric at low temperature ~ 60 °C using a single iron source, without any additional reagents and processing. The method is designed specifically to obtain easy and economical deposition of functional nanoparticles on large substrate areas. Structural and chemical investigations revealed the formation of β-FeOOH having tetragonal crystal structure on CF fabric. The morphological studies revealed the growth of spindle-shaped β-FeOOH NPs having diameter of 75–80 nm. The as-synthesized β-FeOOH/CF was also applied and qualitatively tested as a phosphate adsorbent, in which it was observed that the for high concentration phosphate solutions, optimized phosphate adsorption was achieved on β-FeOOH/CF in short durations of time whereas lower concentrations solutions required longer duration.