Phosphate Release Research Articles

Biochar as composite of phosphate fertilizer: Characterization and agronomic effectiveness

Organomineral phosphate fertilizers (OMP) may reduce phosphate release rate and its direct contact to the soil solid phase, increasing the effectiveness of phosphorus (P) fertilization. This study aimed to evaluate the effect of granulating biochar (BC) with triple superphosphate (TSP) in two forms (blend or coated) and three proportions (5, 15 and 25%, w/w) on the P release kinetics and plant growth. A successive plant trial using two soils of contrasting P buffering capacities and five P doses (0, 20, 40, 80 and 120 mg kg−1) was set to investigate the agronomic effectiveness of OMP that presented the slowest P release kinetic. The kinetic test showed that within the first 1.5 h, TSP, OMP blend and OMP coated fertilizers released 92, 82 and 36% of total P, respectively. Thereby, BC addition to TSP reduced the P release rate, mainly due to coating. The fertilizers coated with 15% and 25% BC (C15 and C25, respectively) presented the slowest P release rate. For the plant trial, C15 was chosen because it requires less BC when compared with C25 fertilizer. In the first crop, C15 provided more P to plants, especially in the soil with high P buffering capacity, which increased by 10% and 20% the P uptake and the P recovered by the plant when compared with TSP, respectively. In the sandy soil, fertilizers C15 and TSP showed the same performances regarding yield, P uptake and P recovery rate. At consecutive cultivation, regardless of the soil type, P sources (C15 and TSP) did not differ in yield, P uptake and P recovery. Therefore, biochar-based organomineral phosphate fertilizer can enhance P use efficiency in high P-fixing tropical soils, increasing P recovery and uptake when compared with TSP.

Assessment of the Effect of Glycine, Oxalic Acid and Nitrogen-Phosphorus-Potassium (NPK) Fertilizer as Nutrient Supplement Using Phosphate and Oxalic Acid as Indices

This study evaluated the release profiles of phosphate and oxalic acid in soils treated with oxalic acid a low molecular weight organic acid and glycine an amino acid compared with NPK fertilizer monitored over a period of 21 days. The soil treated with oxalic acid and glycine released higher phosphate and oxalic acid than that treated with NPK fertilizer. The soil treated with oxalic acid released higher phosphate than that which was treated with glycine while higher oxalic acid was observed in the soil treated with glycine rather than for that treated with oxalic acid. Significant effects were observed between the treatment and the length of time for phosphate release (P<0.05) while for the release of oxalic acid, there was no significant effect between the treatment (P>0.05) but with increase in length of time (P<0.05). This demonstrates the efficient ability of oxalic acid and glycine as substitutes for phosphate fertilizers.

Injectable Electrical Conductive and Phosphate Releasing Gel with Two-Dimensional Black Phosphorus and Carbon Nanotubes for Bone Tissue Engineering.

Injectable hydrogels have unique advantages for the repair of irregular tissue defects. In this study, we report a novel injectable carbon nanotube (CNT) and black phosphorus (BP) gel with enhanced mechanical strength, electrical conductivity, and continuous phosphate ion release for tissue engineering. The gel utilized biodegradable oligo(poly(ethylene glycol) fumarate) (OPF) polymer as the cross-linking matrix, with the addition of cross-linkable CNT-poly(ethylene glycol)-acrylate (CNTpega) to grant mechanical support and electric conductivity. Two-dimensional (2D) black phosphorus nanosheets were also infused to aid in tissue regeneration through the steady release of phosphate that results from environmental oxidation of phosphorus in situ. This newly developed BP-CNTpega-gel was found to enhance the adhesion, proliferation, and osteogenic differentiation of MC3T3 preosteoblast cells. With electric stimulation, the osteogenesis of preosteoblast cells was further enhanced with elevated expression of several key osteogenic pathway genes. As monitored with X-ray imaging, the BP-CNTpega-gel demonstrated excellent in situ gelation and cross-linking to fill femur defects, vertebral body cavities, and posterolateral spinal fusion sites in the rabbit. Together, these results indicate that this newly developed injectable BP-CNTpega-gel owns promising potential for future bone and broad types of tissue engineering applications.

Structural and Mechanistic Principles of ABC Transporters

ATP-binding cassette (ABC) transporters constitute one of the largest and most ancient protein superfamilies found in all living organisms. They function as molecular machines by coupling ATP binding, hydrolysis, and phosphate release to translocation of diverse substrates across membranes. The substrates range from vitamins, steroids, lipids, and ions to peptides, proteins, polysaccharides, and xenobiotics. ABC transporters undergo substantial conformational changes during substrate translocation. A comprehensive understanding of their inner workings thus requires linking these structural rearrangements to the different functional state transitions. Recent advances in single-particle cryogenic electron microscopy have not only delivered crucial information on the architecture of several medically relevant ABC transporters and their supramolecular assemblies, including the ATP-sensitive potassium channel and the peptide-loading complex, but also made it possible to explore the entire conformational space of these nanomachines under turnover conditions and thereby gain detailed mechanistic insights into their mode of action.

In vitro and toxicological assessment of dexamethasone sodium phosphate loaded pH sensitive Pectin-g-poly(AA)/PVP semi interpenetrating network

Herein, we developed and characterized pH responsive semi interpenetrating network (semi-IPN) of Pectin-g-poly(AA)/PVP by free radical polymerization. These hydrogels were developed to overcome hurdles associated with; i) mechanical strength of formed system which was dealt by the use of combination of natural (pectin) and synthetic (PVP) polymers and ii) oral administration of drugs requiring action in distal part of gastrointestinal tract which was addressed by employing pectin and acrylic acid which conferred pH sensitivity due to carboxylic group in their structure.Structurally and morphologically, developed semi-IPN hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Scanning electron microscopy (SEM) and X-ray diffraction (XRD). Chemically, they were evaluated for swelling and release kinetics. Semi-IPN hydrogels restricted the swelling of system and therefore the release of dexamethasone sodium phosphate (DSP) at pH 1.2 but released it in controlled manner at pH 7.4 by non-Fickian diffusion.. Biologically, acute toxicity testing of developed semi-IPN hydrogels, revealed biocompatibility and safety of hydrogels after oral administration. Conclusively, prepared semi-IPN hydrogels showed good mechanical properties, swelling, biocompatibility, pH dependent DSP release for possible treatment of inflammatory bowel diseases.

Biodegradable fertilizer nanocomposite hydrogel based on poly(vinyl alcohol)/kaolin/diammonium hydrogen phosphate (DAhP) for controlled release of phosphate

Ever-degrading environment due to the application of a large amount of agrochemicals, like fertilizers into the soil, has raised the concern for implementing such measures which would not only reduce the chemical incorporation into the soil, but will also benefit the crops by shooting up the fertilizer utilization by the same. Henceforth, biodegradable formulations for phosphate are essentially required to undergird the evolution of modern day agriculture. Naturally occurring phosphate could not suffice the demands of global agriculture, and so, it has to be applied synthetically in the form of agrochemical. Taking the very facts into consideration, the preparation of a novel biodegradable formulation of nanocomposite hydrogel using PVA as polymeric matrix, kaolin clay as mechanical binder and DAhP as phosphate fertilizer is attempted in the present study. The analysis of final formulation was done using techniques like FT-IR, XRD and SEM. The synthesized compound is named PDK. It shows 66.6 g/g equilibrium swelling; shows 10 times swelling its own weight in 1 h of immersion and attained equilibrium after 3 h. Factors affecting swelling behavior like content of kaolin, temperature and pH have also been investigated which revealed that 1–3 wt% kaolin, 35–40 °C temperature and 6–7 pH are the best optimum conditions for PDK hydrogel to show best results in release and swelling. The release study for phosphate was done by volumetric ammonium phosphomolybdate method by dispersing the sample in water and soil and checking the release at an interval of 3 days for 30 days which revealed 88.8% release in water and 76.3% release in soil. The formulation shows considerable controlled release of DAhP and also presents a scope for the development of biodegradable phosphate-based controlled release fertilizer.

Force and phosphate release from Arp2/3 complex promote dissociation of actin filament branches

Networks of branched actin filaments formed by Arp2/3 complex generate and experience mechanical forces during essential cellular functions, including cell motility and endocytosis. External forces regulate the assembly and architecture of branched actin networks both in vitro and in cells. Considerably less is known about how mechanical forces influence the disassembly of actin filament networks, specifically, the dissociation of branches. We used microfluidics to apply force to branches formed from purified muscle actin and fission yeast Arp2/3 complex and observed debranching events in real time with total internal reflection fluorescence microscopy. Low forces in the range of 0 pN to 2 pN on branches accelerated their dissociation from mother filaments more than two orders of magnitude, from hours to <1 min. Neither force on the mother filament nor thermal fluctuations in mother filament shape influenced debranching. Arp2/3 complex at branch junctions adopts two distinct mechanical states with different sensitivities to force, which we name "young/strong" and "old/weak." The "young/strong" state 1 has adenosine 5'-diphosphate (ADP)-P i bound to Arp2/3 complex. Phosphate release converts Arp2/3 complex into the "old/weak" state 2 with bound ADP, which is 20 times more sensitive to force than state 1. Branches with ADP-Arp2/3 complex are more sensitive to debranching by fission yeast GMF (glia maturation factor) than branches with ADP-P i -Arp2/3 complex. These findings suggest that aging of branch junctions by phosphate release from Arp2/3 complex and mechanical forces contribute to disassembling "old" actin filament branches in cells.

Omega 3 and Azadirachta Indica J. Seed Oil Inhibit Hemoglobin Polymerization and Modulate Erythrocyte Membrane Atpases in Sickle Cell Disease (SCD)

Back ground: Functional foods/Nutraceuticals efficacy depends on both its composition and the physicochemical properties of the components that used in their formulation. Vegetable oil can play an important role. Several studies are shown that omega 3 (0.2%) and Azadirachta indica J. seed oil (0.4%) have antisickling, antioxidant and anti-haemolytic properties. Objective: The purpose of this present study was conducted to determine effects of omega 3 and Azadirachta indica J. seed oil on hemoglobin polymerization and erythrocyte membrane ATPases in Sickle Cell Disease (SCD). Method: The ability for the omega 3 and Azadirachta indica J. seed oil to inhibit sickle cell hemoglobin polymerization and improve the Fe2+/Fe3+ ratio of HbS blood were assed using spectroscopic method. The activities of three ATPases (Na+/K+; Ca2+; and Mg2+-ATPases ) were investigated by the kinetic method following the release of inorganic phosphate (Pi) by ATP taking into account the determination of the total membrane proteins of erythrocytes by Bradford’s method. Results: The lowest potential was obtained with Azadirachta indica J. seed oil (AO: 0.4% v/v) corresponding significantly (p &lt;0.05) to the highest potential of inhibition of polymerization (83.11 ± 8%) compared to that obtained with omega 3 (ω3 0.2% v/v) estimated at 68.15±7%. The greatest Fe2+Fe3+ ratio was obtained (6.65±1.68) with AO (0.4% v/v) corresponding significantly (p &lt;0.05) to the greatest rate of increase of oxyhemoglobin (79.05±3%) compared to that obtained with ω3 (0.2% v/v) estimated at 70.58±5%. As for the activities of Na+/K+, Ca2+ and Mg2+-ATPases expressed in μmole Pi/mg protein/hour x 10-3, there was an increase in the activities of Na+/K+ and Ca2+-ATPases (203.82±41 and 190.48±32) with AO (0.4% v/v), but without any significant difference (p&gt;0.05) compared to those obtained with ω3 (0.2% v/v) (188.66±9 and 235.61±52). However, for Mg2+-ATPase, there was rather a significant decrease (p &lt;0.05) in these activities ranging from 181.9±32 for ω3 (0.2% v/v) to 124.00±21 for AO (0.4% v/v). Conclusion: The Azadirachta indica J. seed oil at a concentration of 0.4% v/v offered the best potential inhibition of hemoglobin S polymerization, oxyhemoglobin increase rate and the best ATPastic activities. Keywords: Omega 3 - Azadirachta indica J. seed oil - sickle cell disease - polymerization - Fe2+/Fe3+ ratio - ATPase activities.

Biodegradation of Malathion Using Pseudomonas stutzeri(MTCC 2643)

Pesticides are applied in agricultural fields for controlling pest population to achieve crop protection. But they cause damage to nontarget organisms and affect the quality of environment including water, air and soil. The present study has been designed to test the efficiency of Pseudomonas stutzerion the degradation of malathion. The bacterial strain was subjected to 50, 100, 150 and 200 ppm of malathion in minimal broth for 30 hours and changes in orthophosphate levels, pH and turbidity were monitored for every six hours. Efficiency of free and immobilized cells were compared for orthophosphate release. Influence of different sugars on degradation was also compared. Degradation of 150 ppm of malathion was confirmed with UV-Visible spectrophotometric analysis and HPLC analysis. The data were subjected to two way analysis of variance and the results are discussed.

Rapid pyritization in the presence of a sulfur/sulfate-reducing bacterial consortium

Sedimentary pyrite (FeS2) is commonly thought to be a product of microbial sulfate reduction and hence may preserve biosignatures. However, proof that microorganisms are involved in pyrite formation is still lacking as only metastable iron sulfides are usually obtained in laboratory cultures. Here we show the rapid formation of large pyrite spherules through the sulfidation of Fe(III)-phosphate (FP) in the presence of a consortium of sulfur- and sulfate-reducing bacteria (SRB), Desulfovibrio and Sulfurospirillum, enriched from ferruginous and phosphate-rich Lake Pavin water. In biomineralization experiments inoculated with this consortium, pyrite formation occurred within only 3 weeks, likely enhanced by the local enrichment of polysulfides around SRB cells. During this same time frame, abiotic reaction of FP with sulfide led to the formation of vivianite (Fe3(PO4)2·8H2O) and mackinawite (FeS) only. Our results suggest that rates of pyritization vs. vivianite formation are regulated by SRB activity at the cellular scale, which enhances phosphate release into the aqueous phase by increased efficiency of iron sulfide precipitation, and thus that these microorganisms strongly influence biological productivity and Fe, S and P cycles in the environment.

Increased silicon concentration in fen peat leads to a release of iron and phosphate and changes in the composition of dissolved organic matter

Prior studies have shown that silicon (Si) increases the dissolution of iron (Fe) phosphates, releasing phosphorus (P) into the soil solution of fen peat and thereby changing the composition of organic matter (OM). We formulated three questions on the occurring processes: [i] Does high Si concentration cause a mobilization of Fe phosphates? [ii] Does this mobilization result in a higher concentration of P, Fe, and dissolved organic carbon? [iii] Are there changes in the composition of organic matter?To this end, we conducted a laboratory experiment adding amorphous silica to fen peat and analyzed Fe mineralogy and carbon quality of the peat material by X-ray absorption spectroscopy (XAS).Under high Si concentration, significantly higher concentrations of P and Fe were found in soil solution. Moreover, XAS data indicated a dissolution of Fe (II) phosphates and a change in the composition of OM available to microbes with decreasing contributions of carboxylic groups and quinones.We propose to explain the effects as follows: under high Si concentration Fe (II) phosphates dissolve and OM rich in carboxylic groups are mobilized. As the nutrient concentration in the soil solution increased, the degradation of oxidized components of the OM, such as quinones and carboxylic groups is enhanced.

Amino Acids Extract from Black Bean Seeds (Phaseolus Vulgaris L.)Inhibit Hemoglobin Polymerizationand Modulate Erythrocyte Membrane Atpases In Sickle Cell Disease (SCD)

Back ground: The basic extracts involved in the formulation of functional foods/nutraceutics must first be the subject of preclinical and clinical trials. The several studies were shown that amino acids extract from black bean seeds (Phaseolus vulgaris L.) have antisickling, antioxidant and anti-haemolitic properties. Objective: The objective of this study is to investigate the effect of amino acids extract from black bean seeds (Phaseolus vulgaris L.) on hemoglobin polymerization and erythrocytes membrane ATPases activities in Sickle Cell Disease (SCD). Method: The ability for the amino acids extract to inhibit sickle cell hemoglobin polymerization and improve the Fe2+/Fe3+ ratio of HbSS blood were assed using spectroscopic method. The activities of three ATPases (Na+/K+; Ca2+; and Mg2+-ATPases) were investigated by the kinetic method following the release of inorganic phosphate (Pi) by ATP taking into account the determination of the total membrane proteins of erythrocytes by Bradford’s method. Result: The lowest potential of inhibition was obtained (39.98±2%) with the amino acids extract at 12 mg/mL corresponding significantly (p&lt;0.05) to the highest potential of inhibition of polymerization (71.16±2%). The greatest Fe2+Fe3+ ratio was obtained (3.94±2%) with the amino acids extract at 12 mg/mL corresponding significantly (p&lt;0.05) to the best rates increase of oxy-hemoglobin (48.73±2%). The red blood cells membranes ATPase activity were estimated and expressed as μmol of Pi/mg of protein/hour x 10-3 there was an increase in the activities of Na+/ K+ and Ca2+-ATPases (255.98±62 and 282.98±36 respectively) at the concentration of 12 mg/mL of extract compared to the negative control (167.36±60 and 236.91±62 respectively). However, for Mg2+-ATPase, there is rather a significant reduction (p&lt;0.05) in this activity (286.71±51 against 146.53±35) obtained in the presence of the amino acid extract at 12 mg/mL). Conclusion: The amino acids extract of black bean seeds (Phaseolus vulgaris L.) at a concentration of 12 mg/mL offered the best inhibition potentials of hemoglobin S polymerization, increase rates of oxyhemoglobin and the best ATPasic activities. Keywords: Amino acid extracts; black bean seeds; sickle cell disease; polymerization; Fe2+/Fe3 + ratio; ATPase activities

Degradation mechanism of tributyl phosphate by UV/H2O2 treatment and parameters optimization towards the design of a pilot reactor

ABSTRACT While activated sludge treatment is currently the preferred process for the removal of tributyl phosphate (TBP) at the mg.L−1 level, it is well known that this recalcitrant molecule is incompletely degraded, stimulating research into alternative approaches, such as advanced oxidation. The aim of this study was to characterize the degradation mechanism of TBP during ultraviolet/H2O2 treatment using 31P NMR, ionic chromatography and total organic carbon analysis. The effects of initial pH, amount of oxidant and pollutant concentration were also assessed using an experimental design approach. The results of this parametric study show that ultraviolet/H2O2 photo-oxidation efficiently degrades TBP at concentrations up to 600 mg.L−1, with >90% phosphate release and up to 95% removal of total organic carbon within 1 h. The data also show that the main reaction intermediates are short carboxylic acids, resulting from the released alkyl groups, meaning that an interesting application of this process may be to rapidly pre-treat industrial effluent upstream of activated sludge reactors.

Effect of in-stream impoundment on water quality of a suburban stream

This study aims to confirm the effect of a small stream impoundment on phosphorus and nitrogen dynamics in a suburban watershed. The results show that the phosphate concentration in the water body was significantly higher than that in the inflowing water under ordinary flow conditions. The phosphorus promotes algal growth that causes significant diurnal dissolved oxygen variation because of photosynthesis and respiration. The phosphate exchange between the sediment and overlying water was mainly controlled by diffusion flux rather than by advective flux seepage because of large amounts of phosphorus accumulated on the surface of the sediment. When a flood occurs, the phosphorus-enriched water is flushed downstream by rain-swollen currents. In summary, an impoundment affects in-stream phosphorus concentration through organic matter degradation and the release of phosphate in the sediment.

Comparison of the Influences of Cadmium Toxicity to Phosphate Removal in Activated Sludge Separately Fed by Glucose and Acetic Acid as Carbon Sources

This study used high and low concentrations of glucose and acetic acid as carbon sources in two aerobic-anoxic-oxic (A2O) processes. Trials were shock loaded with different concentrations of Cd2+. It was observed that the substrate utilization rate decreased when glucose concentration increased and thus the activated sludge of A2O preferred acetic acid as a carbon source over glucose. Under anaerobic conditions, activated sludge readily transformed the substrate into poly-b-hydroxybutyrate (PHB) by the Entner–Douderoff (ED) pathway with ease, but not into poly-b-hydroxyvalerate (PHV) by the Embden–Meyerhof–Parnas (EMP) pathway. However, ED pathway was suppressed more severely by cadmium shock loading than that of the EMP pathway. The shock loading of Cd2+ greatly inhibited the anaerobic phosphate release rate with a half inhibition concentration of 10 mg L−1 when acetic acid was used as a substrate. The phosphate removal efficiency of A2O with acetic acid was affected by Cd2+ shock loading more than that of glucose. Therefore, A2O with glucose as a substrate could tolerate the Cd2+ shock loading better than that of A2O with acetic acid. This study also showed that polyphosphate accumulating organisms (PAOs) were more sensitive to Cd2+ toxicity than that of glycogen accumulating organisms (GAOs). With the addition of Cd2+, PHB/PHV synthesis/degradation was inhibited more apparently in acetic acid trials than that of glucose trials.

A single power stroke by ATP binding drives substrate translocation in a heterodimeric ABC transporter.

ATP-binding cassette (ABC) transporters constitute the largest family of primary active transporters, responsible for many physiological processes and human maladies. However, the mechanism how chemical energy of ATP facilitates translocation of chemically diverse compounds across membranes is poorly understood. Here, we advance the quantitative mechanistic understanding of the heterodimeric ABC transporter TmrAB, a functional homolog of the transporter associated with antigen processing (TAP) by single-turnover analyses at single-liposome resolution. We reveal that a single conformational switch by ATP binding drives unidirectional substrate translocation. After this power stroke, ATP hydrolysis and phosphate release launch the return to the resting state, which facilitates nucleotide exchange and a new round of substrate binding and translocation. In contrast to hitherto existing steady-state assays, our single-turnover approach uncovers the power stroke in substrate translocation and the tight chemomechanical coupling in these molecular machines.

Zeta potential changing nanoemulsions: Impact of PEG-corona on phosphate cleavage.

The aim of this study was to evaluate the impact of a PEG-corona on oily droplets of a nanoemulsion on phosphate cleavage on their surface. A PEG-free nanoemulsion composed of 60% oleic acid, 30% Capmul MCM EP and 10% Span 85 being additionally stabilized by 1% cetyltrimethylammonium bromide (CTAB) and 3% phosphatidic acid (PA) was evaluated regarding phosphate release, zeta potential change and mucus permeation properties. In order to evaluate the impact of PEG-corona on phosphate release 10%, 20% and 30% of polyethoxylated-35 castor oil were incorporated in the nanoemulsion. The developed PEG-free nanoemulsion exhibited the droplet size of 123nm with PDI of 0.24, whereas the droplet size of the nanoemulsions containing PEG ranged from 166nm to 128nm with PDI about 0.26. In case of the PEG-free formulation enzymatically induced phosphate cleavage was 3-fold and 7-fold higher than that from formulations containing 20% and 30% PEG-surfactant, respectively. Accordingly, the zeta potential shift of PEG-free formulation reached ~Δ 40mV within 4h, whereas zeta potential of PEG-containing formulations did not show any significant changes remaining constant at ~-30mV. In contrast, PEG-containing formulations exhibited a 3.3-fold to 4-fold higher mucus permeation than the PEG-free formulation. According to the results, a PEG-corona has a great impact on phosphate cleavage and zeta potential change, which has to be taken into consideration for the development of highly efficient zeta potential changing nanocarriers, as zeta potential constitutes one of the crucial parameter regarding the permeation properties through physiological barriers.

Modulatory Effects of Acute Aerobic Moderate Exercise on Purinergic Enzymes in Sedentary and Physically Active Males

Exercise promotes biochemistry and physiological adaptations, leading to health benefits. Purinergic signaling is a well‐known system of cellular communication, based in extracellular nucleotides and nucleosides that modulate inflammatory, coagulatory and vascular activities. However, data about the effects of exercise in purinergic signaling remain limited. Thus, the main goal of present work was to evaluate the influence of acute aerobic moderate exercise on blood plasma nucleotidases in eutrophic sedentary (EUSED), overweight sedentary (OWSED) and physically active (ACT) male individuals. This study was approved by local Ethics Committee under protocol 2.452.427, being in agreement with the declaration of Helsinki. Twenty‐four healthy male individuals were divided into 3 groups: EUSED (N=8, BMI=23.51±2.01 Kg/m2, 26.38±2.97 years), OWSED (N=8, BMI=27±76 Kg/m2, 25.75±2.92 years) and ACT (N=8, BMI=23.96±1.35 Kg/m2, 23.13±3.18 years). Subjects were evaluated to collect clinical data and performed a cardiopulmonary exercise test to maximal oxygen uptake (VO2MAX) determination. Seven days after evaluation, subjects realized 30 minutes of exercise on treadmill with 70% VO2MAX. Blood samples were taken pre‐, post‐exercise and post‐1h of exercise. NTPDases and 5′‐nucleotidase activities were quantified by release of inorganic phosphate from ATP, ADP and AMP hydrolysis. NPP activity was assessed using p‐Nph‐5′‐TMP as substrate. Adenine nucleotides and nucleosides were quantified by HPLC. Data were analyzed using two‐way ANOVA repeated measures. ATP (EUSED: p=0.001; OWSED: p=0.015; ACT: p=0.002), ADP (EUSED: p=0.001; OWSED: p=0.009; ACT: p=0.001), AMP (EUSED: p=0.001; OWSED: p=0.001; ACT: p=0.001) and p‐Nph‐5′‐TMP (EUSED: p=0.001; OWSED: p=0.001; ACT: p=0.001) hydrolysis increased from pre‐ to post‐exercise among the groups. Post‐1h after exercise, ATP hydrolysis remained increased in ACT group (p=0.019), ADP in OWSED (p=0.03) and AMP in OWSED (p=0.001) and ACT (p=0.03). ATP (EUSED: p&lt;0.001; OWSED: p&lt;0.001; ACT: p&lt;0.001) and ADP (EUSED: p&lt;0.001; OWSED: p&lt;0.001; ACT: p&lt;0.001) plasma levels decreased from pre‐ to post‐exercise and remained decreased post‐1h after exercise among the groups. Adenosine (EUSED: p&lt;0.001; OWSED: p=0.011; ACT: p=0.01), inosine (EUSED: p&lt;0.001; OWSED: p&lt;0.001; ACT: p&lt;0.001) and uric acid (EUSED: p&lt;0.001; OWSED: p=0.001; ACT: p=0.021) plasma levels increased from pre‐ to post‐exercise. Adenosine levels remained increased post‐1h exercise in all groups. There was no significant differences among the groups. Our results indicate that acute aerobic moderate exercise transiently increases NTPDases, 5′‐nucleotidase and NPP activities in plasma, decreasing levels of pro‐inflammatory and pro‐thrombotic molecules as ATP and ADP, increasing levels of cytoprotective molecules as adenosine and inosine in sedentary, overweight and physically active subjects.Support or Funding InformationNacional Council of Scientific and Technological Development (CNPq, Brazil) and Coordination for the Improvement of Higher Education Personnel (CAPES, Brazil) supported this work.

The release of organic matter, nitrogen, phosphorus and heavy metals from erythromycin fermentation residue under heat-activated persulfate oxidation conditioning

Erythromycin fermentation residue (EFR) is one kind of biological waste with high organic matter content. The recycling of EFR is not only beneficial to the environmental protection, but also to the economic development. In this study, the release of organic matter, nitrogen (N), phosphorus (P) and heavy metals (HMs) from EFR under heat-activated persulfate (PS) oxidation conditioning was investigated. Results indicated that oxidation conditioning promoted the release of soluble chemical oxygen demand (SCOD). Heat-activated PS oxidation conditioning boosted the release of total nitrogen (TN), ammonia‑nitrogen (NH4+-N) and nitrate‑nitrogen (NO3−-N) into the supernatant, as well as the decomposition of organic nitrogen (ON). Concurrently, heat-activated PS oxidation conditioning facilitated the release of total phosphorus (TP), orthophosphate (PO43−-P) and organic phosphorus (OP) into the supernatant, and the decomposition of OP. Furthermore, heat-activated PS oxidation conditioning resulted in the increase of release efficiencies of HMs. Therefore, heat-activated PS oxidation conditioning was beneficial to the release of organic matter, nutrients and HMs.

HspA1A, a 70‐kDa heat‐shock protein, contains several distinct lipid‐binding sites

HspA1A, a stress‐inducible seventy‐kilodalton heat shock protein (Hsp70), is a molecular chaperone that plays critical roles in protein homeostasis and cell survival. In addition to its functions in protein homeostasis, HspA1A also functions at different cellular membranes in stressed and cancer cells, where it binds to lipids, including phosphatidylserine (PS) and Bis(Monoacylglycero)Phosphate (BMP). Although the interactions between HspA1A and lipids have important biological consequences, their mechanistic details remain elusive and unexplored because the amino acids responsible for the lipid binding remain largely uncharacterized and the relationship between the chaperone and lipid‐binding functions remains unknown. To clarify the mechanism of the HspA1A‐lipid interactions, we first characterized the properties of a mutation from Tryptophan to Phenylalanine (W90F), known to affect binding of HspA1A to BMP and a Lysine to Alanine (K71A) mutation, which results in complete loss of the chaperone function. Experiments using the lipid vesicle sedimentation (LVS) method and Surface Plasmon Resonance revealed that although the W90F‐HspA1A binding to BMP was different from the WT, this mutation did not affect the binding to PS. Furthermore, our results revealed that the K71A mutation did not significantly change the binding of HspA1A to lipids under any of the conditions tested. These results allowed us to make two predictions: first, the lipid‐binding sites for PS and BMP are lipid‐specific, and second, the chaperone and lipid‐binding functions are distinct. To support the first prediction, we used a combination of structural superimpositions, sequence alignments, and literature observations and predicted three putative lipid‐binding regions on the HspA1A molecule. We tested these predictions using the LVS assay for 20 single or double mutations spanning two of these regions. Our results revealed that only two of these mutations affected the binding to PS, while a third one altered the binding to BMP. To test the second prediction, we performed a series of experiments to determine the effect of lipid binding to the secondary structure and chaperone functions of HspA1A. We used Circular dichroism spectrometry, measured the release of inorganic phosphate, and determined the rate of refolding of chemically denatured beta‐galactosidase in the presence or absence of particular lipid. These experiments revealed that lipid binding did not alter the secondary structure of the protein and affected neither the rate of ATP hydrolysis nor the rate of protein refolding. Together our findings provide further evidence that HspA1A binds to PS and BMP using different amino acid sites and support the notion that the chaperone and lipid‐binding functions of HspA1A do not overlap. These findings provide the basis for future experiments to test the effects of these mutations on the membrane‐localized functions of HspA1A in cancer and stressed cells.Support or Funding InformationThis project was supported by funds from NIH