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Oxalate, the simplest dicarboxylic acid, is a prevalent antinutrient that chelates with various metals and can lead to the formation of kidney stones in humans. The accurate detection of the oxalate concentration in food and the cultivation of low-oxalate crops are important for enhancing public health. In this study, we established a high-throughput and highly sensitive technique for oxalate detection using ultra-high-performance liquid chromatographic–triple quadrupole tandem mass spectrometry (UPLC-QqQ-MS/MS). Additionally, we overexpressed the gene O7, which encodes oxalyl-CoA synthetase in the maize oxalate degradation pathway, resulting in O7-OE lines. By employing the UPLC-QqQ-MS/MS method to measure oxalate levels in these transgenic lines, we observed that the oxalate content in the kernels of O7-OE lines was reduced by approximately 43%, with a concurrent increase in some micronutrients such as zinc. Importantly, the transgenic maize showed normal seed storage compound accumulation or other agronomic characteristics. In summary, we developed a high-throughput detection method that advances oxalate measurement. Furthermore, by generating new maize germplasm with diminished oxalate, our work offers potential health advantages to consumers. [ABSTRACT FROM AUTHOR]

The electrochemical oxygen reduction reaction (2e− ORR) offers a promising approach for H2O2 production, yet developing highly active, selective, and stable electrocatalysts remains a challenge. In this work, a phase reconstruction strategy is presented to synthesize an oxalate‐adsorbed nickel hydroxide electrocatalyst (Ni(OH)2‐C2O4) through the self‐dissociation of nickel oxalate in an alkaline medium, leading to a notable enhancement in H2O2 yield at elevated current densities. Remarkably, Ni(OH)2‐C2O4 exhibits a 2e− selectivity exceeding 93% across a broad voltage range (0.0 to 0.5 V vs RHE) in 0.1 M KOH, outperforming pristine Ni(OH)2. When deployed as a gas diffusion electrode in a flow cell, the Ni(OH)2‐C2O4 catalyst demonstrates stable operation for 50 h at 200 mA cm−2, with a Faradaic efficiency surpassing 90% and a peak H2O2 yield of 6.2 mol g−1cat h−1. Comprehensive advanced characterizations, including in situ Raman spectroscopy, transient photovoltage spectra, and transient potential scanning spectra, coupled with post‐ORR analyses, reveal that surface‐adsorbed oxalate groups on Ni(OH)2 enhance the interfacial reaction kinetics between active Ni sites and reactants by inducing a charge trapping effect and forming a hydrogen‐bonded network, facilitating robust and high‐yield H2O2 production. [ABSTRACT FROM AUTHOR]

Urolithiasis is a medically significant crystallization process affecting the urinary tract. Kidney stones exhibit considerable diversity as they form in complex environments containing various molecules and pathogens. Understanding the formation and occurrence of kidney stones is essential for developing strategies to prevent or reduce the invasiveness of treatments. In this study, we investigated over 300 cases of urolithiasis in Styria, Austria. The composition of the stones was evaluated using infrared spectroscopy and scanning electron microscopy. Most stones were found to be heterogeneous, predominantly composed of calcium oxalate, followed by calcium phosphate. Other components such as struvite, uric acid, and cystine were present to a lesser extent and were more likely to form homogeneous crystals. Analyzing the occurrence of these different stone types provides valuable insights into the formation processes of kidney stones and can aid in the prevention of urolithiasis in the future. [ABSTRACT FROM AUTHOR]

Alkaline EDTA solution has been previously identified as an effective leaching agent for solubilising rare-earth oxalates. These oxalates are the product of an oxalic acid conversion leach dissolving monazite and redepositing the salt. Pervious work suggested a significant increase in recovery was observed between pH 8 and 10; we have demonstrated that, in an excess of EDTA, this is not the case, and the dissolution is similar. While demonstrating that, at a nominal solid loading of 100 g/L, 0.2 M EDTA solution produced the highest dissolution, elevated solids require an equivalent increase in lixiviant concentration driven by consumption. Very-high-solution concentrations (>50 g/L dissolved TREEs) were achieved at a high solid loading, indicating both that a solution equilibrium is yet to be reached and that a build-up of oxalate in the system (estimated at ~1 M) does not impact the leach efficiency. We have also demonstrated the recycling of EDTA to use in multiple stages as well as the ability to recover oxalate from this solution. [ABSTRACT FROM AUTHOR]

Calcium oxalate (CaOx) kidney stones may be associated with urinary tract infections (UTIs). However, the mechanisms for this association are not well-established. The objective of this study was to investigate the effect of oxalate on immunity and UTI development in vivo. Female Sprague-Dawley rats were fed a control diet for 3 days before continuing this diet or starting a 5% Hydroxy-L-proline diet (HLP; oxalate precursor) for 7 days. Rats were subsequently infected transurethrally with Uropathogenic E. coli (UPEC, a bacterium that causes UTI) and sacrificed 3 days later. Urine, blood, kidney, and bladder samples were collected. Urinary oxalate levels, renal CaOx crystal deposition, inflammatory markers, and the bacterial load were assessed using ion chromatography-mass spectrometry, immunohistochemistry, qRT-PCR, western blotting, enzyme-linked immunosorbent assays, or colony forming unit assays. Animals fed HLP and infected with UPEC had a significant increase in urinary oxalate levels, renal CaOx deposition, pro-inflammatory macrophages, pro-inflammatory cytokines, and bacterial loads compared to animals fed the control diet with UPEC infection. In addition, HLP-fed animals had significantly reduced anti-inflammatory renal macrophages and anti-inflammatory cytokine levels in their plasma, urine, and kidneys. These findings suggest that oxalate may play a novel role in the propagation of UTI development. [ABSTRACT FROM AUTHOR]

AbstractIntroductionMethodsResultsDiscussionConclusionTo the best of our knowledge, clinically significant endogenous ethylene glycol production has never been reported in humans, very seldom reported in other animals or microorganisms, and then only under rare and specific conditions. We describe the detailed investigations we undertook in two adult monozygotic twin sisters to ascertain whether they were producing endogenous ethylene glycol.Two previously healthy monozygotic adult twin sisters presented with recurrent episodes of apparent ethylene glycol poisoning beginning at age 35, requiring chronic hemodialysis to remove ethylene glycol and its metabolites as well as to restore metabolic homeostasis. The sisters denied ingestion or exposure to ethylene glycol. At their request, they were admitted to hospital under strict supervision to exclude surreptitious ingestion of ethylene glycol and to evaluate the need for treatment. Hemodialysis was withheld during this prospective study. Twin A was admitted for 14 days and twin B for 11 days. Serial biochemical analyses were performed in blood and urine. Clinical exome sequencing and mitochondrial deoxyribonucleic acid sequencing were also completed.In both twins, ethylene glycol was detected in urine, along with intermittent increases in concentrations of lactate, glycolate, and glycine in blood and/or urine. Blood ethylene glycol concentrations, however, remained <62 mg/L (<1 mmol/L) but became positive soon after discharge. The oxalate concentration remained normal in blood and urine. Plasma and urine amino acid profiles showed intermittent small increases in glycine, serine, taurine, proline, and/or alanine concentrations. Exome sequencing and mitochondrial deoxyribonucleic acid sequencing were non-diagnostic. Neither twin has been admitted with metabolic acidosis nor ethylene glycol poisoning since chronic hemodialysis was started. Twin A developed a calcium oxalate dihydrate lithiasis.Mitochondrial disease, methylmalonic/propionic/isovaleric aciduria, primary hyperoxaluria, and analyte error were all excluded in these twins, as were obvious common environmental exposures.Detailed investigations were performed in adult monozygotic twin sisters to ascertain whether they were producing endogenous ethylene glycol. Alternative explanations were excluded to the very best of our efforts and knowledge. Global metabolomics, gut microbiome analyses, and whole genome sequencing are pending. [ABSTRACT FROM AUTHOR]

Emerging research on the microbiome highlights the significant role of gut health in the development of kidney stones, indicating that an imbalance in gut bacteria or dysbiosis can influence the formation of stones by altering oxalate metabolism and urinary metabolite profiles. In particular, the overabundance of specific bacteria such as Enterococcus and Oxalobacter spp., which are known to affect oxalate absorption, is observed in patients with urolithiasis. This study investigates the effects of gut dysbiosis on urolithiasis through fecal microbiota transplantation (FMT) from patients to rats and its impact on urinary mineral excretion and stone formation. Fecal samples from eight patients with calcium oxalate stones and ten healthy volunteers were collected to assess the gut microbiome. These samples were then transplanted to antibiotic-pretreated Wistar rats for a duration of four weeks. After transplantation, we evaluated changes in the fecal gut microbiome profile, urinary mineral excretion rates, and expression levels of intestinal zonula occluden-1 (ZO-1), SLC26A6 and renal NF-κB. In humans, patients with urolithiasis exhibited increased urinary calcium and oxalate levels, along with decreased citrate excretion and increased urinary supersaturation index. The fecal microbiota showed a notable abundance of Bacteroidota. In rodents, urolithiasis-FMT rats showed urinary disturbances similar to patients, including elevated pH, oxalate level, and supersaturation index, despite negative renal pathology. In addition, a slight elevation in the expression of renal NF-κB, a significant intestinal SLC26A6, and a reduction in ZO-1 expression were observed. The gut microbiome of urolithiasis-FMT rats showed an increased abundance of Bacteroidota, particularly Muribaculaceae, compared to their healthy FMT counterparts. In conclusion, the consistent overabundance of Bacteroidota in both urolithiasis patients and urolithiasis-FMT rats is related to altered intestinal barrier function, hyperoxaluria, and renal inflammation. These findings suggest that gut dysbiosis, characterized by an overgrowth of Bacteroidota, plays a crucial role in the pathogenesis of calcium oxalate urolithiasis, underscoring the potential of targeting the gut microbiota as a therapeutic strategy. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction (OER) is a primary bottleneck that disturbs the efficient hydrogen production from water using renewable electricity. Despite extensive studies, current benchmark NiFe oxyhydroxide catalysts need further development to reduce significant overpotentials for efficient OER. Here, we show that an oxalate-derived OER catalyst immediately converted to NiFe hydroxides in KOH is a promising candidate as a suitable OER catalyst. We find the significant influence of varying water content on morphological changes and Fe dispersion, impacting the intrinsic OER kinetics of the catalysts. Furthermore, the synthesis temperature proves crucial in controlling oxalate growth rates and suppressing Fe penetration into the bulk region of oxalates, resulting in a more uniform formation and widespread distribution of surface Fe sites. The optimized catalyst exhibits remarkable and stable catalytic performance, recording a current density of 200 mA cm⁻2 at an overpotential of 320 mV for 300 h. We present the significant influence of varying water content and synthesis temperature on nano-sized oxalate growth, consequently impacting the OER. [Display omitted] • The NiFe oxalate rapidly transforms into nanostructured NiFe oxyhydroxides upon immersion in KOH for OER. • The synthetic temperature and solution composition effects for the in-situ growth of oxalate are identified. • Microscopic and in-situ spectroscopic evidence revealed the nature of the catalyst phase and compositions. • The nano-pyramid-like oxalate exhibits the best catalytic performance. [ABSTRACT FROM AUTHOR]

Low-molecular-weight organic acids (LMWOAs) are essential O-containing metal-binding ligands involved in maintaining metal homeostasis, various metabolic processes, and plant responses to biotic and abiotic stress. Malate, citrate, and oxalate play a crucial role in metal detoxification and transport throughout the plant. This review provides a comparative analysis of the accumulation of LMWOAs in excluders, which store metals mainly in roots, and hyperaccumulators, which accumulate metals mainly in shoots. Modern concepts of the mechanisms of LMWOA secretion by the roots of excluders and hyperaccumulators are summarized, and the formation of various metal complexes with LMWOAs in the vacuole and conducting tissues, playing an important role in the mechanisms of metal detoxification and transport, is discussed. Molecular mechanisms of transport of LMWOAs and their complexes with metals across cell membranes are reviewed. It is discussed whether different endogenous levels of LMWOAs in plants determine their metal tolerance. While playing an important role in maintaining metal homeostasis, LMWOAs apparently make a minor contribution to the mechanisms of metal hyperaccumulation, which is associated mainly with root exudates increasing metal bioavailability and enhanced xylem loading of LMWOAs. The studies of metal-binding compounds may also contribute to the development of approaches used in biofortification, phytoremediation, and phytomining. [ABSTRACT FROM AUTHOR]

Gold electrode modification with nafion and WO3 has been done for oxalate ion detection. The voltammogram of oxalate ion on the surface gold with and without modification showed a significant difference. This means that the modified gold electrode is sensitive to oxalate ions. The performance of the modified electrode in different pH (5, 7, and 12) in the KCl solution also has been studied using cyclic voltammetry. The range of the measurement is from – 1.0 to + 1.0 at a scan rate of 100 mV s -1. The result showed that the optimum measurement pH is 12 with an anodic peak at 0.143 V and no reduction peak. The measurements of 0, 50, 100, 150, 200, and 250 mg L-1 oxalic ion also have been conducted, showing a linear increase in current. The equation obtained is y = 0.5426 x + 0.9127. In addition, the modified gold electrode showed good selectivity towards oxalate detection, as cyclic voltammetry measurements of some interference components did not produce redox peaks in the oxalate oxidation potential range. These findings indicate that gold electrodes modified with Nafion/WO3 significantly affect the potential development of electrochemical oxalate sensors. [ABSTRACT FROM AUTHOR]

Plants have a great impact on human health. Oxalate is a harmful compound found in some plants. Oxalate interferes with digestion and absorption of nutrients. Furthermore, the origin of most kidney stones is caused by calcium oxalate. Consumption of these plants in the diet of people with kidney stones should be limited. This review identifies plants with high oxalate and also introduces a proven strategy to reduce exposure to oxalates. In this study, search was performed with the keywords of dietary exposure, amount, evaluation, oxalate, and food on Scopus, PubMed, Science Direct, and Web of Science. Manuscripts of the last ten years were considered. 576 studies were obtained and 35 articles were finally chosen according to exclusion and inclusion criteria. Among the plants, the highest amount belongs to the Licorice with 3569.3 ± 319.7 mg/100g. The amount of oxalate in unripe fruits is also higher. Large amounts of oxalate have been reported in some high-consumption plants around the world, including spinach, sweet potatoes, Brassica spp, white beans, soybeans, fenugreek, and onions. Furthermore, to reduce the amount of exposure, good agricultural practices to prevent oxalate accumulation in plants, boiling high oxalate plants, consumption of calcium supplements, probiotics, and dairy foods are recommended. [ABSTRACT FROM AUTHOR]

Abstract Emerging research on the microbiome highlights the significant role of gut health in the development of kidney stones, indicating that an imbalance in gut bacteria or dysbiosis can influence the formation of stones by altering oxalate metabolism and urinary metabolite profiles. In particular, the overabundance of specific bacteria such as Enterococcus and Oxalobacter spp., which are known to affect oxalate absorption, is observed in patients with urolithiasis. This study investigates the effects of gut dysbiosis on urolithiasis through fecal microbiota transplantation (FMT) from patients to rats and its impact on urinary mineral excretion and stone formation. Fecal samples from eight patients with calcium oxalate stones and ten healthy volunteers were collected to assess the gut microbiome. These samples were then transplanted to antibiotic-pretreated Wistar rats for a duration of four weeks. After transplantation, we evaluated changes in the fecal gut microbiome profile, urinary mineral excretion rates, and expression levels of intestinal zonula occluden-1 (ZO-1), SLC26A6 and renal NF-κB. In humans, patients with urolithiasis exhibited increased urinary calcium and oxalate levels, along with decreased citrate excretion and increased urinary supersaturation index. The fecal microbiota showed a notable abundance of Bacteroidota. In rodents, urolithiasis-FMT rats showed urinary disturbances similar to patients, including elevated pH, oxalate level, and supersaturation index, despite negative renal pathology. In addition, a slight elevation in the expression of renal NF-κB, a significant intestinal SLC26A6, and a reduction in ZO-1 expression were observed. The gut microbiome of urolithiasis-FMT rats showed an increased abundance of Bacteroidota, particularly Muribaculaceae, compared to their healthy FMT counterparts. In conclusion, the consistent overabundance of Bacteroidota in both urolithiasis patients and urolithiasis-FMT rats is related to altered intestinal barrier function, hyperoxaluria, and renal inflammation. These findings suggest that gut dysbiosis, characterized by an overgrowth of Bacteroidota, plays a crucial role in the pathogenesis of calcium oxalate urolithiasis, underscoring the potential of targeting the gut microbiota as a therapeutic strategy.

Abstract Calcium oxalate (CaOx) kidney stones may be associated with urinary tract infections (UTIs). However, the mechanisms for this association are not well-established. The objective of this study was to investigate the effect of oxalate on immunity and UTI development in vivo. Female Sprague-Dawley rats were fed a control diet for 3 days before continuing this diet or starting a 5% Hydroxy-L-proline diet (HLP; oxalate precursor) for 7 days. Rats were subsequently infected transurethrally with Uropathogenic E. coli (UPEC, a bacterium that causes UTI) and sacrificed 3 days later. Urine, blood, kidney, and bladder samples were collected. Urinary oxalate levels, renal CaOx crystal deposition, inflammatory markers, and the bacterial load were assessed using ion chromatography-mass spectrometry, immunohistochemistry, qRT-PCR, western blotting, enzyme-linked immunosorbent assays, or colony forming unit assays. Animals fed HLP and infected with UPEC had a significant increase in urinary oxalate levels, renal CaOx deposition, pro-inflammatory macrophages, pro-inflammatory cytokines, and bacterial loads compared to animals fed the control diet with UPEC infection. In addition, HLP-fed animals had significantly reduced anti-inflammatory renal macrophages and anti-inflammatory cytokine levels in their plasma, urine, and kidneys. These findings suggest that oxalate may play a novel role in the propagation of UTI development.

Primary hyperoxaluria (PH) type 1 is a rare autosomal recessive disorder of glyoxylate metabolism. Its prevalence is 1–3 cases/million people. Glyoxylate is the precursor of oxalate which is believed to be produced by oxidation in liver peroxisomes. Serine-pyruvate aminotransferase/alanine-glyoxylate aminotransferase is an enzyme involved in the metabolism of glyoxylate. In the absence of this enzyme, oxalate and glycolate are overproduced leading to hyperoxaluria. This causes urolithiasis or nephrocalcinosis, which are conditions caused by the deposition of calcium oxalate. Due to its rarity and heterogeneous phenotype, it remains unrecognized due to which diagnosis is delayed, ending up in end-stage renal disease (ESRD) and ultimately death. Hence, early diagnosis and simultaneous hepatorenal transplant remain the mainstay to avoid systemic oxalosis. Here, we discuss a case of a 43-year-old female who underwent combined liver–kidney transplant with a history of multiple episodes of renal calculi since childhood ultimately landing into ESRD in view of PH type 1.

Vegetable soybean has high nutritional value and offers functional benefits to human body. However, its use in cooking is still limited, mainly due to the lack of knowledge about its properties. In addition, the availability of cultivars for human consumption is reduced. Therefore, this study was conducted in Botucatu, Brazil, to assess the potential of grain soybean (GS) and dual-purpose soybean (DPS) cultivars for consumption as vegetable soybean (VS). Pods were harvested at R6 stage, and the contents of bioactive compounds (total phenolic compounds, flavonoids, antioxidant activity and proteins) and antinutritional components (nitrates, oxalate, alkaloids and tannins) were evaluated. The cultivars showed the same protein content, not differing statistically from each other, as well as for nitrate and oxalate. The content of phenolic compounds and total antioxidant activity of the SG cultivar differed statistically from the content of the DPS and VS cultivars, respectively. According to the results, the GS cultivar, with pods harvested at R6 stage, showed nutraceutical quality and contents of antinutritional compounds similar to those of the two cultivars proposed for the vegetable soybean. [ABSTRACT FROM AUTHOR]

Background: Nephrolithiasis is the most common illness affecting the urinary system. It affects 600,000 Americans annually and about 12% of the world's population. It caused by a concentration of crystals that exits the kidney and genitourinary system. Calcium stones, primarily composed of calcium phosphate or oxalate, are present in about 80% of patients with nephrolithiasis. Kidney stones can be avoided by controlling the production of oxalate stones through the low oxalate dietary sources and regulating other factors that affect oxalate absorption. Objectives: The purpose of this literature review is to explain how to maintain a low-oxalate diet and other factors, such as enzymes, oxalate precursors, and bacteria in the colon, affect urine oxalate excretion and help prevent the formation of kidney stones. Methods: A summary of this literature was compiled using data from numerous internet resources. Ten earlier research RCTs or observational studies with statistical analysis—that met a number of inclusion criteria were used to support the goals of this work. The journal is available for open access, its publication year is at least 2014. Discussion: Consuming more water, DASH, low calcium and salt diet, and a low-oxalate diet can all considerably reduce the excretion of oxalate. Conversely, a poor dietary pattern has been associated with an increased risk of kidney stones. Oral formulations ALLN-177, Oxabact, and OxDC are helpful in lowering urinary oxalate levels. Conclusion: Kidney stone disease may be avoided by adopting a low-oxalate and low-precursor diet. Latar Belakang: Nefrolitiasis merupakan penyakit yang banyak terjadi pada sistem saluran kemih. Penyakit ini mempengaruhi 600.000 orang Amerika setiap tahunnya dan sekitar 12% populasi dunia. Hal ini disebabkan oleh peningkatan konsentrasi kristal di sistem genitourinari. Pada pasien nefrolitiasis, 80% diantaranya disebabkan oleh pembentukan batu kalsium, terutama fosfat atau oksalat. Nefrolitiasis dapat dihindari dengan mengendalikan produksi batu oksalat melalui sumber makanan rendah oksalat dan mengatur faktor lain yang mempengaruhi penyerapan oksalat.Tujuan: Penulisan literatur ditujukan untuk mengetahui pengaturan pola makan rendah oksalat dan faktor lain seperti enzim, prekursor oksalat dan bakteri di usus sebagai pencegahan pembentukan batu oksalat di ginjal dengan menurunkan eksresi oksalat dalam urin. Metode: Literature review dilakukan dengan mengumpulkan berbagai literatur bersumber dari Internet. Digunakan 10 penelitian yang sesuai dengan kriteria inklusi, penelitian RCT ataupun studi observasional, artikel memiliki akses gratis, tahun terbit minimal 2014 Diskusi: Peningkatan konsumsi air, DASH, diet rendah kalsium dan rendah garam dapat menurunkan eksresi oksalat. Pola diet yang buruk dapat meningkatkan risiko pembentukan batu ginjal. Konsumsi ALLN-177, Oxabact dan OxDC membantu menurunkan oksalat urin. Kesimpulan: Pembentukan batu ginjal dapat dihindari dengan menerapkan pola makan rendah oksalat dan rendah prekursor oksalat.

This study investigated the risk profile and the impact of dietary intervention in calcium oxalate stone formers with enteric hyperoxaluria under controlled, standardized conditions. Thirty-seven patients were included in the study. Dietary and 24-h urinary parameters were obtained on the self-selected diet and a balanced, standardized diet. Tests for [13C2]oxalate absorption, calcium- and ammonium chloride-loading were performed. Mean [13C2]oxalate absorption was 18.8%. A significant positive association was observed between urinary oxalate excretion and intestinal oxalate absorption. In addition, urinary oxalate excretion was significantly correlated with dietary oxalate intake. Mean urinary oxalate excretion decreased from 0.841 mmol/24 h on the usual diet to 0.662 mmol/24 h on the balanced diet, corresponding to a reduction of 21.3%. Besides hyperoxaluria, hypocitraturia and hypomagnesuria were the most common urinary abnormalities at baseline, being present in 83.8% and 81.1% of patients, respectively. Urinary citrate increased by 50.9% and magnesium excretion increased by 25.2% on the balanced diet. As a result, the relative supersaturation of calcium oxalate declined significantly (by 36.2%) on the balanced diet. Since 41% of patients on the balanced diet still had a urine volume of less than 2.0 L/24 h, efforts should be made to increase urine volume by increasing fluid intake and reducing intestinal fluid losses. Dietary intervention proved to be effective in reducing urinary oxalate excretion and should be a cornerstone of the treatment of patients with enteric hyperoxaluria. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the dietary content and evaluate the possible related risk factors in patients with calcium oxalate (CaOx) stones Material and Method: A total of 2348 patients with CaOx stone disease and 1024 cases with no signs of stone disease were evaluated concerning the possible dietary content-related risk factors for stone formation. A well-prepared comprehensive questionnaire focused on the diet-related risk factors including fluid intake, sodium, animal protein, black tea, fruit juice, coffee, and vegetables was utilized. Urinary risk factors have been identified and additionally, the patient-related factors and possible effects of physical exercise, and smoking were also well evaluated. Results: Evaluation of our findings demonstrated that 46.2% of study group cases consumed water less than 1 liter per day; black tea consumption was also found to be higher (28.9% consuming black tea >451 cc/day) in cases with CaOx stones. Similarly, consumption of daily coffee, protein, salt, and dairy products was higher in these cases than in the control group. Also, daily physical activity amounts were lower in this group of patients. Lastly, urinary stone-forming risk factors were common in patients with CaOx stone disease. Conclusion: When comparing calcium-containing stones to others, our findings revealed that high salt, black tea, and animal protein consumption were the main stone-forming risk factors. These patients had higher levels of urinary risk factors than the general population. [ABSTRACT FROM AUTHOR]

Jejunocolic anastomosis (JCA) is a surgical procedure that can result in various complications. Depending on how much of the jejunum remains, these patients are often defined as having intestinal failure (IF) because of short bowel syndrome (SBS). One of the significant complications among these patients is the formation of calcium oxalate renal stones. It has been estimated that 24% of patients with a JCA develop symptomatic renal stones. This narrative review aims to explore the nursing and dietary management strategies for individuals with oxalate stones following JCA. This includes providing adequate hydration, limiting dietary intakes of fat and oxalate, and optimising dietary intake of fluid and calcium whilst discussing the evidence for dietary magnesium, vitamin C and citric acid. [ABSTRACT FROM AUTHOR]

Describing risk factors and outcomes in kidney transplant recipients with oxalate nephropathy (ON) may help elucidate the pathogenesis and guide treatment strategies. We used a large single‐center database to identify patients with ON and categorized them into delayed graft function with ON (DGF‐ON) and late ON. Incidence density sampling was used to select controls. A total of 37 ON cases were diagnosed between 1/2011 and 1/2021. DGF‐ON (n = 13) was diagnosed in 1.05% of the DGF population. Pancreatic atrophy on imaging (36.4% vs. 2.9%, p = 0.002) and gastric bypass history (7.7% vs. 0%; p = 0.06) were more common in DGF‐ON than with controls with DGF requiring biopsy but without evidence of ON. DGF‐ON was not associated with worse graft survival (p = 0.98) or death‐censored graft survival (p = 0.48). Late ON (n = 24) was diagnosed after a mean of 78.2 months. Late ON patients were older (mean age 55.1 vs. 48.4 years; p = 0.02), more likely to be women (61.7% vs. 37.5%; p = 0.03), have gastric bypass history (8.3% vs. 0.8%; p = 0.02) and pancreatic atrophy on imaging (38.9% vs. 13.3%; p = 0.02). Late ON was associated with an increased risk of graft failure (HR 2.0; p = 0.07) and death‐censored graft loss (HR 2.5; p = 0.10). We describe two phenotypes of ON after kidney transplantation: DGF‐ON and late ON. Our study is the first to our knowledge to evaluate DGF‐ON with DGF controls without ON. Although limited by small sample size, DGF‐ON was not associated with adverse outcomes when compared with controls. Late ON predicted worse allograft outcomes. [ABSTRACT FROM AUTHOR]

Objectives: Citrate, oxalate and cystine in 24-h urine are considered to be associated with the incidence and recurrence risk of urinary stone disease (USD). An evaluation of the LC-MS/MS kit for simultaneous quantification of the three analytes was undertaken. Design: & Methods: The analytical performance of the kit was investigated based on FDA, EMA and CLSI guidelines. To promote the standardization of sample storage, this kit has been applied to perform systematic pre-analytical stability study of these analytes in urine. Results: This method was validated with good linearity with accuracy of 93.1%–104 %. Intra-day and inter-day imprecision were ≤5.55 % and 5.34 %, respectively. Recoveries of citrate, oxalate and cystine added to clinical samples were in the range of 92.0–103 %, 94.8–100 % and 99.0–107 % with CV ≤ 5.52 %. It was recommended that urine preserved with hydrochloric acid could be preferable in consideration of both reliable test results and neglected sample heterogeneity. Conclusions: This kit is suitable for measurement of citrate, oxalate and cystine for understanding the etiology of urinary stones, and the proper storage of urine samples is crucial for the correctness of the test results.

A gas pressure meter-based portable/miniaturized analytical kit was established for rapid and on-site detection of oxalate. Potassium permanganate (KMnO4) and oxalate solution were mixed together in bottle-in-bottle reaction device, a simple oxidation reaction process occurred within 6 min and carbon dioxide (CO2) was generated, inducing the pressure of the sealed bottle changed, which was measured by a portable gas pressure meter. A detectable range of 0.1–6 μmol mL−1 and a detection limit of 0.064 μmol mL−1 were achieved. The proposed analytical method was further used for the analysis of several real samples (spinach, beverages and water samples), with the recoveries of 89–111%. Considering the interferences from the complicated matrix, calcium chloride (CaCl2) was served as a precipitant, oxalate (C2O42−) was precipitated with Ca2+ to form precipitation (CaC2O4), CaC2O4 was then separated from the matrix by centrifuge/filter, eliminating the interferences. It is a rapid, easy-used and interference-free analytical system/device for oxalate on-site and real time analysis.

BackgroundPrimary hyperoxaluria type 1 (PH1) is a genetic disorder resulting in overproduction of hepatic oxalate, potentially leading to recurrent kidney stones, nephrocalcinosis, chronic kidney disease, and kidney failure. Lumasiran, the first RNA interference therapeutic approved for infants and young children, is a liver-directed treatment that reduces hepatic oxalate production. Lumasiran demonstrated sustained efficacy with an acceptable safety profile over 12 months in infants and young children (age 45 ml/min/1.73 m2 if ≥12 months old or normal serum creatinine if

Primary Hyperoxaluria Type 3 (PH3) results from 4-hydroxy-2-oxoglutarate (HOG) aldolase (HOGA) deficiency, which causes an increase in endogenous oxalate synthesis leading to calcium oxalate kidney stone disease. The mechanisms underlying HOG metabolism and increased oxalate synthesis in PH3 are not well understood. We used a Hoga1 knock-out mouse model of PH3 to investigate two aspects of HOG metabolism: reduction to dihydroxyglutarate (DHG), a pathway that may limit oxalate synthesis in PH3, and metabolism to glyoxylate, which is a direct precursor to oxalate. The metabolism of HOG to DHG was highest in liver and kidney cortical tissue, enhanced in the cytosolic compartment of the liver, and preferred NADPH as a cofactor. In the absence of HOGA, HOG to glyoxylate aldolase activity was highest in liver mitoplasts, with no activity present in brain tissue lysates. These findings will assist in the identification of enzymes responsible for the metabolism of HOG to DHG and glyoxylate, which may lead to novel therapeutic approaches to limit oxalate synthesis in those afflicted with PH3.

The widespread used organoarsenicals have drawn attention for decades due to their potential environment risks. In this study, a heterogeneous system of goethite/oxalate irradiated using UVA light (λ = 365 nm) was applied for the removal of ASA, a kind of organoarsenicals used in animal feeding operations as additives, from the aqueous phase through photodegradation. Results showed that the presence of 5 mM of oxalate significantly enhanced the photodegradation efficiency of ASA in the 0.1 g/L of goethite suspended system from 28 to ~100% within 180 min reaction at pH 5. Acid conditions favored the photoreaction rate, compared with neutral and basic conditions. This reaction process was also influenced by the initial concentration of oxalate and ASA. Furthermore, the mechanism study was conducted by quenching experiments and revealed the important roles of ·OH in the degradation of ASA in the goethite/oxalate/UVA system. By analyzing the reaction products, both inorganic arsenic (As(III) and As(V)) and ammonia were detected during the photodegradation of ASA. These findings help to gain a better understanding of the geochemical behavior of ASA in surface water and can also provide a potential treatment method for the organoarsenicals contaminated water. [ABSTRACT FROM AUTHOR]

A role for l -ascorbate as the precursor of several plant compounds adds to its already broad metabolic utility. There are many examples of plant species in which oxalate and l -threonate are formed from l -ascorbate breakdown, and a number of roles have been proposed for this: structural, physiological, and biochemical. On the other hand, the synthesis of l -tartrate from l -ascorbate remains limited to a very few species, amongst which we must be grateful to count the domesticated grapevine Vitis vinifera and its relatives on which wine production is based. Pathways for the degradation of ascorbate were first proposed ~50 years ago and have formed the basis of more recent biochemical and molecular analyses. The present review seeks to summarize some of these findings and to propose opportunities for future research. [ABSTRACT FROM AUTHOR]

Primary hyperoxalurias (PHs) are inherited metabolic disorders marked by enzymatic cascade disruption, leading to excessive oxalate production that is subsequently excreted in the urine. Calcium oxalate deposition in the renal tubules and interstitium triggers renal injury, precipitating systemic oxalate build-up and subsequent secondary organ impairment. Recent explorations of novel therapeutic strategies have challenged and necessitated the reassessment of established management frameworks. The execution of diverse clinical trials across various medication classes has provided new insights and knowledge. With the evolution of PH treatments reaching a new milestone, prompt and accurate diagnosis is increasingly critical. Developing early, effective management and treatment plans is essential to improve the long-term quality of life for PH patients. [ABSTRACT FROM AUTHOR]

Background: Plasma oxalate measurements can be used for the screening and therapeutic monitoring of primary hyperoxaluria. We developed a gas chromatography-mass spectrometry (GC-MS) assay for plasma oxalate measurements with high sensitivity and suitable testing volumes for pediatric populations. Methods: Plasma oxalate was extracted, derivatized, and analyzed by GC-MS. We measured the ion at m/z 261.10 to quantify oxalate and the 13C2-oxalate ion (m/z: 263.15) as the internal standard. Method validation included determination of the linear range, limit of blank, limit of detection, lower limit of quantification, precision, recovery, carryover, interference, and dilution effect. The cut-off value between primary and non-primary hyperoxaluria in a pediatric population was analyzed. Results: The detection limit was 0.78 μmol/L, and the linear range was up to 80.0 μmol/L. The between-day precision was 5.7% at 41.3 μmol/L and 13.1% at 1.6 μmol/L. The carryover was <0.2%. The recovery rate ranged from 90% to 110%. Interference analysis showed that Hb did not interfere with plasma oxalate quantification, whereas intralipids and bilirubin caused false elevation of oxalate concentrations. A cut-off of 13.9 μmol/L showed 63% specificity and 77% sensitivity, whereas a cut-off of 4.15 μmol/L showed 100% specificity and 20% sensitivity. The minimum required sample volume was 250 μL. The detected oxalate concentrations showed interference from instrument conditioning, sample preparation procedures, medications, and various clinical conditions. Conclusions: GC-MS is a sensitive assay for quantifying plasma oxalate and is suitable for pediatric patients. Plasma oxalate concentrations should be interpreted in a clinical context. [ABSTRACT FROM AUTHOR]

To reveal the oxygen evolution reaction (OER) catalytic performance and structure-activity relationship of copper-iron-based metal-organic frameworks (MOFs) at the molecular level, new types of Cu–Fe MOF based materials, Cu 2 Fe/CNT and {CuFe 2 } n /CNT (CNT: carbon nanotube), were synthesized and studied. The results showed that the two materials exhibited different catalytic activities, with the former showing lower activity (Overpotential at the current density of 10 mA cm−2: η 10 = 450 mV, Tafel slope: 92.4 mV dec−1) and the latter showing much higher activity (η 10 = 370 mV, Tafel slope: 64.8 mV dec−1). Further analysis revealed that the performance difference was due to ligand rearrangement between metals in Cu 2 Fe/CNT, which affected the exposure of active metal sites. Meanwhile, the unique three-dimensional MOF structure of {CuFe 2 } n /CNT significantly increased the electrochemical surface area (ECSA), enhancing the electrochemical performance. This study demonstrates how the intricate ligand rearrangement effects in non-precious metal catalysts can greatly influence their performance. Understanding and rationally tuning these coordination interactions is crucial for designing high-performance non-noble metal electrocatalysts. An interesting phenomenon of ligand restructuring was observed in novel Cu–Fe MOF-based materials, Cu 2 Fe/CNT and {CuFe 2 } n /CNT, which greatly influenced their OER performance. These 3-D MOF structures induced by ligands increased the electrochemical surface area (ECSA), resulting in excellent catalytic activity for OER. The materials exhibited a low overpotential of only 370 mV to achieve a current density of 10 mA, with a small Tafel slope of 64.8 mV dec-1. This work inspires future research in designing efficient OER catalysts through ligand tuning strategies. [Display omitted] • Green syntheses of Cu–Fe MOF/CNT with 3-D channel structure. • Cu–Fe MOF/CNT demonstrate good OER activity comparable to commercial IrO 2. • Ligand rearrangement between metals was found to affect OER performance. • In-depth analysis of the catalytic mechanism of OER at the molecular level. [ABSTRACT FROM AUTHOR]

Background: Metabolic reprogramming plays a significant role in the advancement of lung adenocarcinoma (LUAD), yet the precise metabolic changes remain incompletely understood. This study aims to uncover metabolic indicators associated with the progression of LUAD. Methods: A total of 1083 subjects were recruited, including 670 LUAD, 135 benign lung nodules (BLN) and 278 healthy controls (HC). Gas chromatographymass spectrometry (GC/MS) was used to identify and quantify plasma metabolites. Odds ratios (ORs) were calculated to determine LUAD risk factors, and machine learning algorithms were utilized to differentiate LUAD from BLN. Results: High levels of oxalate, glycolate, glycine, glyceric acid, aminomalonic acid, and creatinine were identified as risk factors for LUAD (adjusted ORs>1.2, P<0.03). Remarkably, oxalate emerged as a distinctive metabolic risk factor exhibiting a strong correlation with the progression of LUAD (adjusted OR=5.107, P<0.001; advanced-stage vs. early-stage). The Random Forest (RF) model demonstrated a high degree of efficacy in distinguishing between LUAD and BLN (accuracy = 1.00 and 0.73, F1-score= 1.00 and 0.79, and AUC = 1.00 and 0.76 in the training and validation sets, respectively). TCGA and GTEx gene expression data have shown that lactate dehydrogenase A (LDHA), a crucial enzyme involved in oxalate metabolism, is increasingly expressed in the progression of LUAD. High LDHA expression levels in LUAD patients are also linked to poor prognoses (HR=1.66, 95% CI=1.34-2.07, P<0.001). [ABSTRACT FROM AUTHOR]

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Oxalate degradation is one of lactic acid bacteria's desirable activities. It is achieved by two enzymes, formyl coenzyme A transferase (frc) and oxalyl coenzyme A decarboxylase (oxc). The current study aimed to screen 15 locally isolated lactic acid bacteria to select those with the highest oxalate degradation ability. It also aimed to amplify the genes involved in degradation. MRS broth supplemented with 20 mM sodium oxalate was used to culture the tested isolates for 72 h. This was followed by an enzymatic assay to detect remaining oxalate. All isolates showed oxalate degradation activity to variable degrees. Five isolates demonstrated high oxalate degradation, 78 to 88%. To investigate the oxalate-degradation potential of the selected isolates, they have been further tested for the presence of genes that encode for enzymes involved in oxalate catabolism, formyl coenzyme A transferase (frc) and oxalyl coenzyme A decarboxylase (oxc). Three strains showed bands with the specific OXC and FRC forward and reverse primers designated as (SA-5, 9 and 37). Species-level identification revealed Loigolactobacillus bifermentans, Lacticaseibacillus paracasei, and Lactiplantibacillus plantarum. Preliminary results revealed that the tested probiotic strains harbored both oxc and frc whose products are putatively involved in oxalate catabolism. The probiotic potential of the selected strains was evaluated, and they showed high survival rates to both simulated gastric and intestinal fluids and variable degrees of antagonism against the tested Gram-positive and negative pathogens and were sensitive to clarithromycin but resistant to both metronidazole and ceftazidime. Finally, these strains could be exploited as an innovative approach to establish oxalate homeostasis in humans and prevent kidney stone formation. [ABSTRACT FROM AUTHOR]

Wet‐chemical extraction of soil to quantify pedogenic species or to remove specific compounds prior to other analyses is an established approach in analytical soil mineralogy and soil chemistry. Interpretation and informational value of data derived from long‐established and frequently used extractions, for instance involving dithionite, oxalate/oxalic acid in the dark (AOD), and pyrophosphate (PYR), suffers from nonuniform practical regulation and missing knowledge about potential methodical limitations. In this review, we analyzed potential pitfalls of these frequently used extractions, with the focus on selectivity and completeness of the methods as derived from effects of time dependency and of phase separation. Major problems we identified comprised that time‐dependency of extraction differed between analytical targets, that a multitude of species is attacked, reducing the selectivity for the original analytical target, and that studies on extraction from model compounds, including analytical targets and nontargets, are not universally present. The latter aspect is crucial for the completeness of AOD and PYR extraction that has not been proven for all potential analytical targets of the methods yet. We practically tested citrate (CIT) extraction of aluminum (Al) and iron (Fe) in organic association, using selected models of soil constituents. Apart from a synthesized poorly ordered Si‐rich short‐range ordered aluminosilicate, CIT did not extract Al from nontarget phases, confirming previous studies, but did extract Al and Fe completely from organic associations. In addition to recommendations on the practical use of dithionite‐based, AOD, citrate‐ascorbate (CA), and CIT extraction, we suggest replacing highly problematic PYR extraction by CIT extraction for metals in organic association in soil and using AOD extraction in combination with CA and CIT extraction to avoid potential misinterpretation of ambiguous data. [ABSTRACT FROM AUTHOR]

Convenient and highly sensitive detection of oxalate ions in body fluids is of crucial significance for disease prevention, diagnosis, and monitoring of treatment effectiveness. Establishing a simple solid-state electrochemiluminescence (ECL) sensing system for highly sensitive detection of oxalate ions is highly desirable. In this work, a solid ECL sensor was fabricated by immobilizing the commonly used emitter ruthenium(II)tris(bipyridine) (Ru(bpy)32+) on a double-layered bipolar silica nanochannel array film (bp-SNA)-modified electrode, enabling sensitive detection of oxalate ions in serum or urine samples. Cost-effective and readily available indium tin oxide (ITO) was used as the supporting electrode. Convenient fabrication of multiple negatively charged SNA (n-SNA)-modified ITO electrodes was achieved through the one-step Stöber solution growth method. Subsequently, a positive outer layer film (p-SNA) was rapidly prepared using an electrochemical-assisted self-assembly method. The double-layered bipolar silica nanochannel array film achieved stable immobilization of Ru(bpy)32+ on the electrode surface, facilitated by the electrostatic adsorption of Ru(bpy)32+ by n-SNA and the electrostatic repulsion by p-SNA. Utilizing oxalate ions as a co-reactant for Ru(bpy)32+, combined with the electrostatic enrichment of oxalate ions by p-SNA, the constructed sensor enabled highly sensitive detection of oxalate ions ranging from 1 nM to 25 μM and from 25 μM to 1 mM, with a detection limit (LOD) of 0.8 nM. The fabricated ECL sensor exhibited high selectivity and good stability, making it suitable for ECL detection of oxalate ions in serum and urine samples. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is an essential nutrient for crops and is applied to agricultural soil to bring or keep the soil at a certain target soil P status in view of an optimal crop yield. Environmental objectives, however, are rarely considered in current P fertilizer recommendations. In this review paper, we argue that current P fertilizer recommendations must be revised in order to balance crop yield, water quality and the use of finite P resources. This revision requires insights into the total pool of reversibly bound P and the capacity of the soil to bind P. Current soil P tests (SPTs) used in routine agronomic soil testing do not provide these insights. We identify the oxalate extraction method as a high-potential agri-environmental SPT as it measures the total pool of reversibly bound P acting as a reserve for plant-available P while it also quantifies the maximum soil P sorption capacity from the simultaneous measurement of amorphous iron- and aluminium-(hydr)oxides. From these results, the Phosphorus Saturation Degree (PSD) can be calculated. We show that those insights are pivotal for the combined assessment of crop response, the risk of P losses to the water system and the judicious use of finite P reserves. In practice, agronomic target P levels should be lowered in soils with a low P sorption capacity to decrease the risk of P leaching. Agronomic target levels should also be lowered in soils with a high P sorption capacity to ensure a judicious use of finite P reserves. [ABSTRACT FROM AUTHOR]

Glyoxylate is a key metabolite generated from various precursor substrates in different subcellular compartments including mitochondria, peroxisomes, and the cytosol. The fact that glyoxylate is a good substrate for the ubiquitously expressed enzyme lactate dehydrogenase (LDH) requires the presence of efficient glyoxylate detoxification systems to avoid the formation of oxalate. Furthermore, this detoxification needs to be compartment‐specific since LDH is actively present in multiple subcellular compartments including peroxisomes, mitochondria, and the cytosol. Whereas the identity of these protection systems has been established for both peroxisomes and the cytosol as concluded from the deficiency of alanine glyoxylate aminotransferase (AGT) in primary hyperoxaluria type 1 (PH1) and glyoxylate reductase (GR) in PH2, the glyoxylate protection system in mitochondria has remained less well defined. In this manuscript, we show that the enzyme glyoxylate reductase has a bimodal distribution in human embryonic kidney (HEK293), hepatocellular carcinoma (HepG2), and cervical carcinoma (HeLa) cells and more importantly, in human liver, and is actively present in both the mitochondrial and cytosolic compartments. We conclude that the metabolism of glyoxylate in humans requires the complicated interaction between different subcellular compartments within the cell and discuss the implications for the different primary hyperoxalurias. [ABSTRACT FROM AUTHOR]

ABSTRACT: Vegetable soybean has high nutritional value and offers functional benefits to human body. However, its use in cooking is still limited, mainly due to the lack of knowledge about its properties. In addition, the availability of cultivars for human consumption is reduced. Therefore, this study was conducted in Botucatu, Brazil, to assess the potential of grain soybean (GS) and dual-purpose soybean (DPS) cultivars for consumption as vegetable soybean (VS). Pods were harvested at R6 stage, and the contents of bioactive compounds (total phenolic compounds, flavonoids, antioxidant activity and proteins) and antinutritional components (nitrates, oxalate, alkaloids and tannins) were evaluated. The cultivars showed the same protein content, not differing statistically from each other, as well as for nitrate and oxalate. The content of phenolic compounds and total antioxidant activity of the SG cultivar differed statistically from the content of the DPS and VS cultivars, respectively. According to the results, the GS cultivar, with pods harvested at R6 stage, showed nutraceutical quality and contents of antinutritional compounds similar to those of the two cultivars proposed for the vegetable soybean.

Oxalate is an organic dicarboxylic acid that is a common component of plant foods. The kidneys are essential organs for oxalate excretion, but excessive oxalates may induce kidney stones. Jupiter microtubule associated homolog 2 (JPT2) is a critical molecule in Ca2+ mobilization, and its intrinsic mechanism in oxalate exposure and kidney stones remains unclear. This study aimed to reveal the mechanism of JPT2 in oxalate exposure and kidney stones. Genetic approaches were used to control JPT2 expression in cells and mice, and the JPT2 mechanism of action was analyzed using transcriptomics and untargeted metabolomics. The results showed that oxalate exposure triggered the upregulation of JPT2, which is involved in nicotinic acid adenine dinucleotide phosphate (NAADP)-mediated Ca2+ mobilization. Transcriptomic analysis revealed that cell adhesion and macrophage inflammatory polarization were inhibited by JPT2 knockdown, and these were dominated by phosphatidylinositol 3-kinase (PI3K)/AKT signaling, respectively. Untargeted metabolomics indicated that JPT2 knockdown inhibited the production of succinic acid semialdehyde (SSA) in macrophages. Furthermore, JPT2 deficiency in mice inhibited kidney stones mineralization. In conclusion, this study demonstrates that oxalate exposure facilitates kidney stones by promoting crystal-cell adhesion, and modulating macrophage metabolism and inflammatory polarization via JPT2/PI3K/AKT signaling.

Rhubarb (Rheum L.) is a well-known medicinal and culinary plant. Apart from its rich nutritional value, rhubarb contains a higher concentration of oxalates. In this study, the content of L-ascorbic acid (AA) and oxalic acid (OA) within three rhubarb species (Rheum rhabarbarum, R. rhaponticum and R. palmatum × wittrockii) differentiated to 16 accessions in a gene bank rhubarb collection (Lednice, Czech Republic) in the condition of conventional production in the South Moravia region during the harvesting period was evaluated. While L-ascorbic acid is essential in human nutrition, oxalic acid is considered toxic, and high doses may cause serious health issues. AA and OA content, the morphology evaluation and ISSR (inter simple sequence repeats)-based genetic analysis were performed. The results of this study confirm the significant influence of taxonomy and harvesting time on the content of AA in Rheum accessions. The content of AA was determined from 6 mg · 100 g-1 to 10 g · 100 g-1 fresh weight (FW) at the beginning of the harvesting season (May) up to 25 mg · 100 g-1 FW at the end of the harvesting period. The content of OA strongly varied from 300 mg · 100 g-1 to 1800 mg · 100 g-1 FW. Regarding the antinutrient character of oxalate, the optimal harvest period of this region was estimated to be from May to early June, when the OA content was the lowest. The role of AA as a precursor of oxalate formation in rhubarb was not affirmed by the results of this study.

Oxalate, the simplest dicarboxylic acid, is a prevalent antinutrient that chelates with various metals and can lead to the formation of kidney stones in humans. The accurate detection of the oxalate concentration in food and the cultivation of low-oxalate crops are important for enhancing public health. In this study, we established a high-throughput and highly sensitive technique for oxalate detection using ultra-high-performance liquid chromatographic–triple quadrupole tandem mass spectrometry (UPLC-QqQ-MS/MS). Additionally, we overexpressed the gene O7, which encodes oxalyl-CoA synthetase in the maize oxalate degradation pathway, resulting in O7-OE lines. By employing the UPLC-QqQ-MS/MS method to measure oxalate levels in these transgenic lines, we observed that the oxalate content in the kernels of O7-OE lines was reduced by approximately 43%, with a concurrent increase in some micronutrients such as zinc. Importantly, the transgenic maize showed normal seed storage compound accumulation or other agronomic characteristics. In summary, we developed a high-throughput detection method that advances oxalate measurement. Furthermore, by generating new maize germplasm with diminished oxalate, our work offers potential health advantages to consumers.

Alkaline EDTA solution has been previously identified as an effective leaching agent for solubilising rare-earth oxalates. These oxalates are the product of an oxalic acid conversion leach dissolving monazite and redepositing the salt. Pervious work suggested a significant increase in recovery was observed between pH 8 and 10; we have demonstrated that, in an excess of EDTA, this is not the case, and the dissolution is similar. While demonstrating that, at a nominal solid loading of 100 g/L, 0.2 M EDTA solution produced the highest dissolution, elevated solids require an equivalent increase in lixiviant concentration driven by consumption. Very-high-solution concentrations (>50 g/L dissolved TREEs) were achieved at a high solid loading, indicating both that a solution equilibrium is yet to be reached and that a build-up of oxalate in the system (estimated at ~1 M) does not impact the leach efficiency. We have also demonstrated the recycling of EDTA to use in multiple stages as well as the ability to recover oxalate from this solution.

Urolithiasis is a medically significant crystallization process affecting the urinary tract. Kidney stones exhibit considerable diversity as they form in complex environments containing various molecules and pathogens. Understanding the formation and occurrence of kidney stones is essential for developing strategies to prevent or reduce the invasiveness of treatments. In this study, we investigated over 300 cases of urolithiasis in Styria, Austria. The composition of the stones was evaluated using infrared spectroscopy and scanning electron microscopy. Most stones were found to be heterogeneous, predominantly composed of calcium oxalate, followed by calcium phosphate. Other components such as struvite, uric acid, and cystine were present to a lesser extent and were more likely to form homogeneous crystals. Analyzing the occurrence of these different stone types provides valuable insights into the formation processes of kidney stones and can aid in the prevention of urolithiasis in the future.

The study examined the composition and forms of iron and aluminium oxides in benchmark soils of central southwestern Nigeria. Soils developed from distinct parent rock types, including coarse-grained granite and gneiss, fine grained biotite gneiss and schist, and the amphibolite complex which correspond to the parent rocks of the soils of Iwo (Typic Paleustults), Egbeda (Rhodic Kandiustults) and Itagunmodi (Typic Haplustults) Associations, respectively, were selected for the study. Notably, these soils collectively encompass approximately 60% of the total land area in central southwestern Nigeria. The less than 2 mm soil fractions were pre-treated with hydrogen peroxide to remove soil organic matter. Thereafter, oxides of Fe and Al were extracted using three different extractants: dithionite-citrate-bicarbonate (DCB) mixtures, acidified ammonium oxalate and sodium pyrophosphate solution. The quantification of Fe and Al oxides contents in the respective extracts were carried out using Inductively Coupled Plasma—Atomic Emission Spectrometry. The research findings indicated that the DCB extractable forms of Fe and Al oxides were more abundant compared to other forms of these oxides, and a substantial portion of these oxides within the soils existed in crystalline form. Among the soil series studied, Itagunmodi series exhibited the highest amount of DCB- and oxalate extractable Fe oxides, while Iwo series had the highest content of Fe and Al oxides extracted by sodium pyrophosphate solution. Importantly, the presence of Fe oxides were found to negatively impact the reactivity of SOM in the soils. [ABSTRACT FROM AUTHOR]

The Acyl-activating enzyme (AAE) 3 gene encodes an oxalyl-CoA synthetase that catalyzes the conversion of oxalate to oxalyl-CoA as the first step in the CoA-dependent pathway of oxalate catabolism. Although the role of this enzyme in oxalate catabolism has been established, its biological roles in plant growth and development are less understood. As a step toward gaining a better understanding of these biological roles, we report here a characterization of the Arabidopsis thaliana aae3 (Ataae3) seed mucilage phenotype. Ruthidium red (RR) staining of Ataae3 and wild type (WT) seeds suggested that the observed reduction in Ataae3 germination may be attributable, at least in part, to a decrease in seed mucilage accumulation. Quantitative RT-PCR analysis revealed that the expression of selected mucilage regulatory transcription factors, as well as of biosynthetic and extrusion genes, was significantly down-regulated in the Ataae3 seeds. Mucilage accumulation in seeds from an engineered oxalate-accumulating Arabidopsis and Atoxc mutant, blocked in the second step of the CoA-dependent pathway of oxalate catabolism, were found to be similar to WT. These findings suggest that elevated tissue oxalate concentrations and loss of the oxalate catabolism pathway downstream of AAE3 were not responsible for the reduced Ataae3 seed germination and mucilage phenotypes. Overall, our findings unveil the presence of regulatory interplay between AAE3 and transcriptional control of mucilage gene expression. [ABSTRACT FROM AUTHOR]

Nephrolithiasis is a common urologic manifestation of Crohn's disease. The purpose of this study was to investigate the clinical characteristics, intestinal oxalate absorption, and risk factors for urinary stone formation in these patients. In total, 27 patients with Crohn's disease and 27 healthy subjects were included in the present study. Anthropometric, clinical, and 24 h urinary parameters were determined, and the [13C2]oxalate absorption test was performed. Among all patients, 18 had undergone ileal resection, 9 of whom had a history of urinary stones. Compared to healthy controls, the urinary excretion values of calcium, magnesium, potassium, sulfate, creatinine, and citrate were significantly lower in patients with Crohn's disease. Intestinal oxalate absorption, the fractional and 24 h urinary oxalate excretion, and the risk of calcium oxalate stone formation were significantly higher in patients with urolithiasis than in patients without urolithiasis or in healthy controls. Regardless of the group, between 83% and 96% of the [13C2]oxalate was detected in the urine within the first 12 h after ingestion. The length of ileum resection correlated significantly with the intestinal absorption and urinary excretion of oxalate. These findings suggest that enteric hyperoxaluria can be attributed to the hyperabsorption of oxalate following extensive ileal resection. Oral supplementation of calcium and magnesium, as well as alkali citrate therapy, should be considered as treatment options for urolithiasis. [ABSTRACT FROM AUTHOR]

The effect of enzyme and different heat treatments on the dehulling of the sesame seed coat were investigated.The amount of crust removed was determined to be 11.23–14.08%for no pre-treatment seed (NPM),seed dipped into boiling water (BW),steam treated seed (ST)and seed kept frozen at −18 °C (FT).While ash contents of sesame seeds change between 2.77% (steam treated sesame seed) and 4.44% (seed peeled using traditional methods), crude protein contents of seeds varied between 20.40% (raw sesame seed) and 24.29%(no-pretreatment).In addition, the oil contents of seeds were determined between 53.85%(raw sesame seed) and 61.83%(no-pretreatment).Also, while oleic acid contents of of seed oils vary between 39.62% (dipped into boiling) and 40.18%(seed peeled using traditional methods),linoleic acid contents of oils ranged from 43.76%(seed peeled using traditional methods) to 44.56%(steam treated). It has been found that the enzyme application is more effective in peeling sesame seed husks than the traditional peel method. [ABSTRACT FROM AUTHOR]