Glycine regulates lipid peroxidation promoting porcine oocyte maturation and early embryonic development.

In vitro-cultured oocytes are separated from the follicular micro-environment in vivo and are more vulnerable than in vivo oocytes to changes in the external environment. This vulnerability disrupts the homeostasis of the intracellular environment, affecting oocyte meiotic completion, and subsequent embryonic developmental competence in vitro. Glycine, one of the main components of glutathione (GSH), plays an important role in the protection of porcine oocytes in vitro. However, the protective mechanism of glycine needs to be further clarified. Our results showed that glycine supplementation promoted cumulus cell expansion and oocyte maturation. Detection of oocyte development ability showed that glycine significantly increased the cleavage rate and blastocyst rate during in vitro fertilization (IVF). SMART-seq revealed that this effect was related to glycine-mediated regulation of cell membrane structure and function. Exogenous addition of glycine significantly increased the levels of the anti-oxidant GSH and the expression of anti-oxidant-related genes (glutathione peroxidase 4 [GPX4], catalase [CAT], superoxide dismutase 1 [SOD1], superoxide dismutase 2 [SOD2], and mitochondrial solute carrier family 25, member 39 [SLC25A39]), decreased the lipid peroxidation caused by reactive oxygen species (ROS) and reduced the level of malondialdehyde (MDA) by enhancing the functions of mitochondria, peroxisomes and lipid droplets (LDs) and the levels of lipid metabolism-related factors (peroxisome proliferator activated receptor coactivator 1 alpha [PGC-1α], peroxisome proliferator-activated receptor γ [PPARγ], sterol regulatory element binding factor 1 [SREBF1], autocrine motility factor receptor [AMFR], and ATP). These effects further reduced ferroptosis and maintained the normal structure and function of the cell membrane. Our results suggest that glycine plays an important role in oocyte maturation and later development by regulating ROS-induced lipid metabolism, thereby protecting against biomembrane damage.

Production of high-quality gametes is the premise of livestock reproduction and conservation of germplasm resources, especially high-quality oocytes, as oocyte quality determines the quality of offspring. Due to the limitations in approaches and the number of mature oocytes in vivo, in vitro maturation (IVM) culture has become an important way to obtain mature oocytes. However, IVM-cultured oocytes are separated from the follicular microenvironment in vivo and are, thus, more vulnerable than in vivo oocytes to changes in the external environment. Our study was conducted to determine if exogenous supplementation of glycine, the highest content of amino acids in oviduct fluid and follicular fluid, can improve oocyte maturation efficiency in vitro, and analyze the mechanism of glycine. This study demonstrated that glycine can maintain redox balance and block reactive oxygen species-induced lipid peroxidation, thereby protecting against biomembrane damage and reducing the occurrence of ferroptosis to maintain normal oocyte development function. This study will provide a theoretical basis for preventing and improving oxidative damage during oocyte culture in vitro.

Removal of fluoride from water using aluminum hydroxide-loaded zeolite synthesized from coal fly ash.

The removal of fluoride from wastewater is essential as the excess accumulation of fluoride in environment is harmful to the health of humans. In this study, the defluorination of water by aluminum hydroxide-coated zeolite (AHZ), which was synthesized from coal fly ash, was investigated in batches. The Langmuir maximum adsorption capacity of fluoride by AHZ reached 18.12 mg/g. Aluminum hydroxide was shown to be the major component that adsorbed fluoride. More than 92% removal of fluoride was achieved within 2 h, and the fluoride adsorption kinetics were well fitted to a pseudo-second-order model. The point of zero charge (pHpzc) of the AHZ was determined to be 5.52. Fluoride adsorption by AHZ depended greatly on pH, and maximum performance was obtained at pH 5.5-6.5. The AHZ showed good selectivity for the adsorption of fluoride in the presence of chloride, nitrate, sulfate, bicarbonate, and acetate ions, and the fluoride was nearly exhausted at a sufficiently high dose. The release of OH- due to fluoride adsorption was confirmed. FTIR and XPS studies further illustrated that the adsorption mechanism of fluoride adsorption on AHZ was ligand exchange with hydroxyl groups and the formation of F-Al bonds.

Coupled influence of pH and dissolved organic carbon on the immobilization of phosphorus by lanthanum-modified zeolite.

Wind-driven waves and currents in shallow lakes frequently trigger the resuspension of sediments in the photic layer, which is characterized with a high pH and high dissolved organic carbon (DOC) concentration. The mechanism of phosphorus-inactivating agents (PIAs) immobilizing phosphorus under the coupled influence of pH and DOC is not clarified, and the applicability of PIAs in eutrophic shallow lakes is thus still doubtful. We found that, under the coupled influence of pH and DOC, the uptake of phosphate by LMZ was affected mainly by pH at low DOC concentrations and by DOC at high DOC concentrations. A high pH (9.3) and high DOC concentration (24.7 mg/L) greatly increased the release of phosphorus from sediment to water. However, the addition of LMZ substantially reduced the P concentrations in water, mainly via capture of dissolved inorganic phosphorus. The results of the reversibility of the adsorption of phosphates and DOC showed that phosphate had much higher affinity than DOC towards LMZ. The phosphate once adsorbed on LMZ was resistant to release when exposed to conditions of either a high pH (9.5), high DOC concentration (250 mg/L) or both; i.e., only <5% of the adsorbed phosphate is releasable. Therefore, we proposed that, to avoid the coupled influence of pH and DOC in the photic layer of eutrophic shallow lakes, LMZ could be applied in multiple low doses in the season when the growth of algae is minimal (a low pH and low DOC concentration).

Effect of algae on phosphorus immobilization by lanthanum-modified zeolite.

Phosphorus-inactivating agents (PIAs) as geoengineering tools in lakes have been investigated extensively, but PIA resuspension in the photic layer occurs frequently in shallow lakes and little is known about the influence of algae on PIA performance. Our results proved that algae increased the dissolved oxygen, pH and dissolved organic carbon concentration substantially. In the absence of sediment, lanthanum modified zeolite (LMZ) as a representative PIA and algae could deplete dissolved inorganic phosphorus (DIP) from water but the former was faster than the latter. When LMZ and algae coexisted, the amount of phosphorus that was captured by LMZ was 3.1 times greater than that taken up by algae. An increase in pH or dissolved organic carbon increased the zero-equilibrium phosphorus concentration (EPC0) of the sediment but LMZ addition could lower the EPC0 and reduce the risk of phosphorus release during the algal blooming season. In the presence of sediment, LMZ reduced the DIP concentration more rapidly and yielded a lower final DIP concentration compared with algae. In conclusion, the influence of algae on the performance of LMZ by (i) taking up DIP to reduce the availability of DIP and convert DIP into a releasable phosphorus form and (ii) increasing the pH and dissolved organic carbon concentration to hinder the adsorption ability of DIP were recognized. The LMZ performed well, even in the presence of algae.

Interactions of phosphate and dissolved organic carbon with lanthanum modified bentonite: Implications for the inactivation of phosphorus in lakes.

Lanthanum-modified bentonite (LMB) is a widely used phosphorus-inactivating agent in lakes. However, dissolved organic carbon (DOC) exists ubiquitously in lakes, and its influence on phosphate binding is still not adequately understood. Our results showed that both phosphate and DOC can be adsorbed by LMB. The Langmuir adsorption maxima of phosphate and DOC were 9.06 mg P/g and 5.31 mg C/g, respectively, generating a C/P molar ratio ∼1.5. When phosphate and DOC coexisted at this ratio, the adsorption of phosphate was not influenced by DOC and vice versa. However, the phosphate capture by LMB was significantly reduced by raising the ratio above ∼9, and the reduction was increased with increasing the ratio. Once adsorbed by LMB, phosphate was essentially not desorbed by DOC, while adsorbed DOC can be mostly liberated by phosphate. It is deemed that phosphate can interact preferentially with La on LMB. However, DOC can still be adsorbed by LMB, even after LMB was saturated with phosphate, which was attributed to (i) the high coordination capacity of La; (ii) the interaction of DOC with the hydroxyl group(s) of the adsorbed phosphate via hydrogen bonding; and (iii) the interaction of DOC with the La sites unoccupied by phosphate. We proposed that LMB can be applied in the season (time) when the DOC/P ratio in lakes is low enough to facilitate the adsorption of phosphate, which will no longer be released into water, even after the C/P ratio is raised later.

The recovery of phosphorus from source-separated urine by repeatedly usable magnetic Fe3O4@ZrO2 nanoparticles under acidic conditions.

The separation of urine at source for phosphorus (P) recovery is attractive taking into account the high P concentration and small volume. However, the treatment of urine is still challenging due to its unpleasant odor and hygiene problems. Because the above problems could be solved by acidification to keep the pH of urine below 4, we propose a novel strategy to recover P from acidified urine using tailored hydrous zirconia-coated magnetite nanoparticles (Fe3O4@ZrO2). This strategy involves the selective adsorption of phosphate by easily separable and reusable Fe3O4@ZrO2, the desorption of adsorbed phosphate, and the precipitation of desorbed phosphate as calcium phosphate fertilizer. The results indicated that at pH 4, the P in synthetic urine was selectively adsorbed and could be exhausted using Fe3O4@ZrO2. Nearly all (>97.5%) of the sequestered P on the Fe3O4@ZrO2 nanoparticles was stripped using ≥1 M NaOH solution and ~100% of the stripped P was then successfully transformed into calcium phosphate, upon adding CaCl2 at pH >12 and a Ca/P molar ratio of 3. The liquid/solid (Fe3O4@ZrO2 particles) mixture could be conveniently separated for reuse using an external magnetic field. The reusability of the Fe3O4@ZrO2 nanoparticles in the extraction of P from synthetic urine was confirmed using five cycles of the adsorption-desorption process and their performance validated using real urine samples. The mechanism of phosphate adsorption was investigated using XPS, FTIR and zeta potential measurements, showing that phosphate was chemically adsorbed on the surface through direct coordination to zirconium atom via ligand exchange.

Immobilization and Release Behavior of Phosphorus on Phoslock-Inactivated Sediment under Conditions Simulating the Photic Zone in Eutrophic Shallow Lakes.

Phosphorus-inactivating agents (PIAs) have increasingly been applied and extensively investigated to control internal phosphorus loading in lakes. However, little is known about the behavior of PIA-amended sediment in terms of phosphorus immobilization and release when the sediment is resuspended in the photic layer, whose environment differs from the lake bed. Lanthanum-modified bentonite (LMB) is a popular PIA product. In this study, the 33 day core incubation experiment under dark conditions showed that capping sediment with LMB efficiently decreased the concentration of total phosphorus, total dissolved phosphorus, and dissolved inorganic phosphorus (DIP) by 90, 87, and 99%, respectively. Resuspension into overlying water under light conditions at high pH, high dissolved organic carbon, and in the presence of algae significantly impedes the performance of LMB. However, the adoption of a higher LMB dose improved the performance, including a reduction in the phosphorus level and control of algal growth. The dynamics of the phosphorus migration when the LMB-inactivated sediment was resuspended into the photic zone mainly involves the release of DIP from the sediment and the uptake of DIP by algae and LMB. In conclusion, a higher dose is needed in the PIA (particularly Phoslock) application in shallow productive lakes where sediment resuspension occurs frequently.

Inactivation of phosphorus in the sediment of the Lake Taihu by lanthanum modified zeolite using laboratory studies.

Release of phosphorus (P) from sediment to overlying water has to be dealt with to address algal blooms in eutrophic lakes. In this study, the sediment from the Lake Taihu was amended with lanthanum modified zeolite (LMZ) to reduce P release under different pH, temperature and anaerobic conditions. LMZ performed well, to decreasing P concentration in Lake Taihu water in the presence of sediment. The EPC0 value, the critical P concentration at which there was neither P adsorption nor P release, was lowered by adding LMZ, suggesting that amendment with LMZ could diminish the risk of P release from the sediment. From the Langmuir isotherm model, the adsorption capacity of phosphate by LMZ was estimated to be 64.1 mgP/g. The LMZ-amended sediment had a higher content of stable P forms (HCl-P and Res-P) and a lower content of P forms with a high (NH4Cl-P and BD-P) or medium-high (NaOH-P and Org-P) risk of release, when compared with the original sediment. The fractionation simulates conditions which release potentially mobile P which can then be simply re-bound to LMZ. At high pH (>9.0), anaerobic condition or high temperature promoted the liberation of P from sediment. However, P release could be greatly inhibited by LMZ. In addition, although Mn2+ and NH4+ ions were released from sediment under the anaerobic condition, the release could also be hindered by adding LMZ. LMZ is a promising P inactivation agent to manage eutrophication in the sediment of Lake Taihu.

Application of zeolite/hydrous zirconia composite as a novel sediment capping material to immobilize phosphorus.

A unique sediment-capping agent consisting of a zeolite/hydrous zirconia composite (ZHZ) was developed and tested for P-immobilization in the overlying water and sediment cores from a freshwater pond. In the ZHZ, NaP1 zeolite was covered with hydrous zirconia, which existed as an amorphous phase. Experimental results in pond water indicated that ZHZ could efficiently remove soluble reactive phosphorus. The 28-day sediment incubation experiments showed that capping sediment with ZHZ resulted in a more efficient, rapid and sustained decrease in P concentration when compared with the traditional alum treatment method. Furthermore, ZHZ increased the sediment stability, resulting in the lowest turbidity, total phosphorus and soluble reactive phosphorus concentrations in overlying water following artificially induced resuspension of sediment. Phosphorus fractionation of sediment showed that the dominant P form transferred from HCl-extractable P to residual P, and the most release-sensitive P (labile P and reductant reactive P) was decreased after ZHZ application. Overall, ZHZ is a highly effective P-immobilization material. ZHZ has high potential as a sediment capping material to control internal P loading in eutrophic water bodies.

[Removal and Recycle of Phosphor from Water Using Magnetic Core/Shell Structured Fe3O4 @ SiO2Nanoparticles Functionalized with Hydrous Aluminum Oxide].

A novel magnetic core/shell structured nano-particle Fe3O4@ SiO2phosphor-removal ahsorbent functionalized with hydrous aluminum oxides (Fe3O4@ SiO2@ Al2O3· nH2O) was synthesized. Fe3O4@ SiO2@ Al2O3· nH2O was characterized by XRD, TEM, VSM and BET nitrogen adsorption experiment. The XRD and TEM results demonstrated the presence of the core/shell structure, with saturated magnetization and specific surface area of 56.00 emu · g⁻¹ and 47.27 m² · g⁻¹, respectively. In batch phosphor adsorption experiment, the Langmuir adsorption maximum capacity was 12.90 mg · g⁻¹ and nearly 96% phosphor could be rapidly removed within a contact time of 40 mm. Adsorption of phosphor on Fe3O4@ SiO2@ Al2O3 · nH2O was highly dependent on pH condition, and the favored pH range was 5-9 in which the phosphor removal rate was above 90%. In the treatment of sewage water, the recommended dosage was 1.25 kg · t⁻¹. In 5 cycles of adsorption-regeneration-desorption experiment, over 90% of the adsorbed phosphor could be desorbed with 1 mol · L⁻¹ NaOH, and Fe3O4@ SiO2@ Al2O3· nH2O could be reused after regeneration by pH adjustment with slightly decreased phosphor removal rate with increasing recycling number, which proved the recyclability of Fe3O4@ SiO2@ Al2O3· nH2O and thereby its potential in recycling of phosphor resources.

Phosphate removal from water by a novel zeolite/lanthanum hydroxide hybrid material prepared from coal fly ash.

This study was undertaken to investigate the effectiveness of the hybrid adsorbent, which was synthesized from coal fly ash and was composed of lanthanum hydroxide and zeolite (La-ZFA), for phosphate removal from water. Long-term repeated adsorption tests for 30 days showed that the maximum removal capacity of the material reached 66.09 mg P/g. The fractionation of adsorbed phosphorus indicated that phosphate immobilized by La-ZFA was quite irreversible and was dominated by HCl-P fraction. It was suggested that the immobilization of phosphate was mainly attributed to lanthanum hydroxide and was slightly influenced by coexistence of other anions (Cl(-), NO3(-), SO4(2-), and HCO3(-)). At a La/P molar ratio between 1.5:1 and 2.0:1, a nearly complete removal (above 98%) of phosphate could be achieved. La-ZFA also exhibited great performance for removing phosphate from lake water (97.29%) as well as the effluent from wastewater treatment plant (97.86%), respectively. In addition, based on the results of the present study, it was believed that La-ZFA could be a potential material for phosphate removal in practical application.

[Study on phosphate removal and recovery by activated alumina].

Activated alumina was studied for removing phosphate from water, and the recovery of adsorbed phosphate on activated aluminum oxide was also tested. Phosphate solution was prepared using distilled water, tap water and Luoshijiang River water, respectively. All the phosphate adsorption tests using activated alumina were proved to be well fitted with Langmuir isotherm and the respective maximum adsorption amount were 20.88, 32.15 and 29.85 mg x g(-1), respectively. The presence of electrolyte in water could be a positive factor for phosphate removal. As the pH value of phosphate solution became lower the Zeta potential of activated alumina increased, which could enhance the phosphate removal efficiency of activated alumina. The recovery tests indicated that NaOH (0.1 mol x L(-1)) solution could almost completely extract the phosphate adsorbed by activated alumina.

Phosphate removal from source separated urine by electrocoagulation using iron plate electrodes.

The aim of this study was to investigate the effects of current density, gap between electrodes, urine dosage, dilution and hydrolysis on phosphate removal from human urine by electrocoagulation technique using iron as electrodes. It was shown that, although a high current density and a long electrolysis time favored the removal of phosphate, an appropriate value for these two parameters can be obtained by taking into account the consumption of energy and iron in addition to P removal. In this study, current density 40 mA/cm2 and electrolysis time 20 min were shown to be optimal for 1.0 L pure urine to achieve nearly a complete removal (98%) efficiency of phosphate under the conditions of electrode area 160 cm2, the stirring speed 150 rpm, and the gap between electrodes 5 mm. Increase of gap between electrodes had little effect on phosphate removal, although it increased the energy consumption dramatically. The use of a high urine dosage reduced the efficiency of phosphate removal but increased the amount of removed phosphate. When pure urine was diluted with tap water, use of a higher tap water proportion for dilution expedited the electrolysis to achieve a nearly complete removal of phosphate in solution, but dilution caused the increase in energy consumption. It was also revealed that the hydrolysis of urine prior to electrocoagulation treatment impeded phosphate removal.

Removal of phosphate from aqueous solution by zeolite synthesized from fly ash.

Fifteen Chinese fly ashes were converted hydrothermally into zeolites, and phosphate immobilization capacity (PIC) of the synthesized zeolites and the corresponding raw fly ashes were determined using an initial phosphate concentration of 1000 mg/L. Results showed that there was a remarkable increase in PIC (from 1.2 to 7.6 times) following the synthesis process. Fractionation of immobilized phosphorus indicated that Fe+Al-P increased most significantly and consistently among all the phosphorus fractions following the conversion of fly ash to zeolite. The PIC and Ca+Mg-P were closely related to Ca content (with r values of 0.9683 and 0.9651, respectively) rather than Mg content (with r values of 0.3920 and 0.3212, respectively). The r values of PIC and Fe+Al-P with Fe content (with r values of 0.4686 and 0.6385, respectively) were higher than those with Al content (with r values of -0.7857 and -0.3770, respectively). Although calcium and iron components were mainly involved in phosphate immobilization, there was no significant change of Ca and Fe content following the conversion of fly ash to zeolite. Increase in dissociated Fe(2)O(3) and specific surface area probably accounted for the enhancement in PIC of synthesized zeolites compared with corresponding fly ashes. The PIC value of zeolites showed a significant correlation with dissociated Fe(2)O(3) (r=0.6186). The specific surface area increased 26.0-89.4 times as a result of the conversion of fly ash to zeolite. The maximum removal of phosphate occurred within different pH ranges for zeolites which were synthesized from high, medium and low calcium fly ashes and this behavior was explained by the reaction of phosphate with calcium and iron components.