Aluminum (Al) is the most abundant metal element in the earth's crust. On acid soils, at pH 5.5 or lower, part of insoluble Al-containing minerals become solubilized into soil solution, with resultant highly toxic effects on plant growth and development. Nevertheless, some plants have developed Al-tolerance mechanisms that enable them to counteract this Al toxicity. One such well-documented mechanism is the Al-induced secretion of organic acid anions, including citrate, malate, and oxalate, from plant roots. Once secreted, these anions chelate external Al ions, thus protecting the secreting plant from Al toxicity. Genes encoding the citrate and malate transporters responsible for secretion have been identified and characterized, and accumulating evidence indicates that regulation of the expression of these transporter genes is critical for plant Al tolerance. In this review, we outline the recent history of research into plant Al-tolerance mechanisms, with special emphasis on the physiology of Al-induced secretion of organic acid anions from plant roots. In particular, we summarize the identification of genes encoding organic acid transporters and review current understanding of genes regulating organic acid secretion. We also discuss the possible signaling pathways regulating the expression of organic acid transporter genes.
Aluminum ; toxicity ; Anions ; Biological Transport ; drug effects ; Citric Acid ; metabolism ; Malates ; metabolism ; Oxalic Acid ; metabolism ; Plant Roots ; drug effects ; metabolism ; Signal Transduction ; physiology

The culture filtrate of Lentinula edodes shows potent antimicrobial activity against the plant pathogenic bacteria Ralstonia solanacearum. Bioassay-guided fractionation was conducted using Diaion HP-20 column chromatography, and the insoluble active compound was not adsorbed on the resin. Further fractionation by high-performance liquid chromatography (HPLC) suggested that the active compounds were organic acids. Nine organic acids were detected in the culture filtrate of L. edodes; oxalic acid was the major component and exhibited antibacterial activity against nine different phytopathogenic bacteria. Quantitative analysis by HPLC revealed that the content of oxalic acid was higher in the water extract from spent mushroom substrate than in liquid culture. This suggests that the water extract of spent L. edodes substrate is an eco-friendly control agent for plant diseases.
Agaricales ; Bacteria* ; Chromatography ; Chromatography, High Pressure Liquid ; Chromatography, Liquid ; Lentinula* ; Oxalic Acid* ; Plant Diseases ; Plants ; Ralstonia solanacearum ; Shiitake Mushrooms* ; Water

This study compared the nutritional composition and antioxidative activity of different parts of Taraxacum coreanum (aerial parts and roots) according to different drying methods (natural drying and freeze-drying). There were no significant differences in vitamin C content in roots depending on the drying methods. However, vitamin A (P<0.01), E (P<0.001) and C (P<0.001) content of aerial parts, and vitamin A (P<0.001) and E (P<0.05) content of roots were significantly higher after freeze-drying compared to natural drying. For organic acids, the oxalic acid content of the aerial parts and roots were the highest. The total polyphenol and total flavonoid content in extracts from the aerial parts (P<0.01) and roots (P<0.05) were significantly higher after freeze-drying compared to natural drying. In addition, the total polyphenol and flavonoid content, DPPH radical scavenging activity, and antioxidative index from the natural drying and freeze-drying of Taraxacum coreanum extracts were significantly higher in the aerial parts compared to the roots (P<0.05). These results suggest that the nutritional composition and antioxidative activity of Taraxacum coreanum are higher in the aerial parts compared to the roots, and higher after freeze-drying compared to natural drying. Therefore, the aerial parts of Taraxacum coreanum could be suggested as an antioxidative functional food source.
Ascorbic Acid ; Functional Food ; Methods* ; Oxalic Acid ; Taraxacum* ; Vitamin A ; Vitamins

Detergents ; Immunohistochemistry ; instrumentation ; Oxalic Acid ; Potassium Permanganate ; Staining and Labeling ; instrumentation

Ethylene glycol (EG) is a sweet-tasting, odorless organic solvent found in many agents, such as anti-freeze. EG is composed of four organic acids: glycoaldehyde, glycolic acid, glyoxylic acid and oxalic acid in vivo. These metabolites are cellular toxins that can cause cardio-pulmonary failure, life-threatening metabolic acidosis, central nervous system depression, and kidney injury. Oxalic acid is the end product of EG, which can precipitate to crystals of calcium oxalate monohydrate in the tubular lumen and has been linked to acute kidney injury. We report a case of EG-induced oxalate nephropathy, with the diagnosis confirmed by kidney biopsy, which showed acute tubular injury of the kidneys with extensive intracellular and intraluminal calcium oxalate monohydrate crystal depositions.
Acidosis ; Acute Kidney Injury ; Biopsy ; Calcium Oxalate ; Central Nervous System ; Depression ; Ethylene Glycol ; Ethylenes ; Glycolates ; Glyoxylates ; Kidney ; Oxalic Acid

It is controversial whether low calcium intake, commonly associated with osteoporosis, results in calcium accumulation in soft tissues. This study was conducted to investigate the effects of low calcium (Ca) and oxalate (ox) intake on soft-tissue Ca deposits and bone metabolism in ovariectomized (ovx) rats. Eight week old female Sprague-Dawley rats were ovariectomized and divided into four groups. The rats were fed experimental diets containing low (0.1%, w/w) or normal (0.5%, w/w) Ca with or without sodium oxalate (1%, w/w); Sham/NCa, Ovx/NCa, Ovx/LCa, Ovx/NCa-ox, Ovx/LCa-ox for 6 weeks. All ovx rats showed a remarkable increase in body and tissue weight, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, blood urea nitrogen, alkaline phosphatase, and decreases in weight, ash, and Ca contents, as well as bone breaking force compared to those in sham rats. Serum Ca concentration was not significantly affected by dietary Ca levels or ox intake. Kidney Ca, ox acid content, and microscopic Ca deposition increased remarkably in the Ovx/LCa-ox group compared to those in the other groups. Ca content in the spleen and aorta also increased significantly, but the weight contents, Ca, bone breaking force, and Ca and oxalic acid in feces decreased significantly in the Ovx/LCa-ox group. Serum parathyroid hormone levels were not significantly different among the groups. These results indicate that low Ca intake decreased bone mineral content and increased Ca deposits in soft tissues, which was aggravated by ox intake in ovx rats. Thus, high ox intake may result in a kidney disorder in patients with osteoporosis who eat a low Ca diet.
Alanine Transaminase ; Alkaline Phosphatase ; Animals ; Aorta ; Aspartate Aminotransferases ; Blood Urea Nitrogen ; Bone Density ; Calcium ; Diet ; Feces ; Female ; Humans ; Kidney ; Osteoporosis ; Ovariectomy ; Oxalic Acid ; Parathyroid Hormone ; Rats ; Rats, Sprague-Dawley ; Salicylamides ; Spleen

OBJECTIVES: The aim of this study was to examine changes in the dentinal fluid flow (DFF) during desensitizing agent application and to compare permeability after application among the agents. MATERIALS AND METHODS: A Class 5 cavity was prepared to exposure cervical dentin on an extracted human premolar which was connected to a sub-nanoliter fluid flow measuring device (NFMD) under 20 cm water pressure. DFF was measured from before application of desensitizing agent (Seal&Protect, SP; SuperSeal, SS; BisBlock, BB; Gluma desensitizer, GL; Bi-Fluoride 12, BF) through application procedure to 5 min after application. RESULTS: DFF rate after each desensitizing agent application was significantly reduced when compared to initial DFF rate before application (p < 0.05). SP showed a greater reduction in DFF rate than GL and BF did (p < 0.05). SS and BB showed a greater reduction in DFF rate than BF did (p < 0.05). CONCLUSIONS: Characteristic DFF aspect of each desensitizing agent was shown in NFMD during the application procedure.
Bicuspid ; Dentin ; Dentin Sensitivity ; Dentinal Fluid ; Glutaral ; Humans ; Methacrylates ; Oxalic Acid ; Permeability ; Water

OBJECTIVE: The aim of this study was to compare the shear bond strengths (SBS) of orthodontic brackets bonded to enamel with a self-etching primer after bleaching, desensitizer application and combined treatment. METHODS: Forty-eight premolars were randomly divided into four groups, each with n = 12 premolar samples. The four groups were; Group1: 15% hydrogen-peroxide office bleaching agent (Illumine Office-IO), Group 2: IO + BisBlock Oxalate Dentin-Desensitizer, Group 3: Bis Block Oxalate Dentin-Desensitizer, Group 4: No treatment (control). Twenty-four hours after bonding, the specimens were tested in SBS at a crosshead speed of 5 mm/min until the brackets debonded. The failure mode of the brackets was determined by a modified adhesive remnant index. RESULTS: Bleaching, bleaching and desensitizer treatment, and desensitizer treatment alone all significantly reduced SBS of the orthodontic brackets (p = 0.001). No statistically significant difference was found between Group 1, Group 2 and Group 3 (Group 1-Group 2, p = 0.564; Group 1-Group 3, p = 0.371; Group 2-Group 3, p = 0.133). The predominant mode of failure for the treatment groups (Group1, Group 2 and Group 3) was at the enamel-adhesive interface leaving 100% of the adhesive on the bracket base. CONCLUSIONS: Bleaching and desensitizer treatment should be delayed until the completion of orthodontic treatment.
Adhesives ; Bicuspid ; Dental Enamel ; Orthodontic Brackets ; Oxalic Acid

OBJECTIVETo study the different and the variety of four organic acids in leaves of Isatis indigotica among different cultivated populations in water stress condition and healthy plant.

METHODFour kinds of organic acids, such as oxalic acid, malic acid, ascorbic acid and citric acid from the leaves, were detected by HPLC.

RESULTSignificant differences of four organic acids in the leaves of Beijing, Mongolia, Hebei and Shanxi cultivated populations. Compared with the healthy plant, the content of oxalic acid, malic acid and citric acid in water stress were increased, while the content of ascorbic acid was decreased.

CONCLUSIONContents of four organic acids can act as the guideline factor in I. indigotica because they were related with the water stress condition.

Ascorbic Acid ; chemistry ; metabolism ; China ; Chromatography, High Pressure Liquid ; Citric Acid ; chemistry ; metabolism ; Dehydration ; Isatis ; chemistry ; metabolism ; Malates ; chemistry ; metabolism ; Oxalic Acid ; chemistry ; metabolism ; Plant Leaves ; chemistry ; metabolism

This study was aimed to develop an instrument for real-time measurement of fluid conductance and to investigate the hydrodynamics of dentinal fluid. The instrument consisted of three parts; (1) a glass capillary and a photo sensor for detection of fluid movement, (2) a servo-motor, a lead screw and a ball nut for tracking of fluid movement, (3) a rotary encoder and software for data processing. To observe the blocking effect of dentinal fluid movement, oxalate gel and self-etch adhesive agent were used. BisBlock (Bisco) and Clearfil SE Bond (Kuraray) were applied to the occlusal dentin surface of extracted human teeth. Using this new device, the fluid movement was measured and compared between before and after each agent was applied. The instrument was able to measure dentinal fluid movement with a high resolution (0.196 nL) and the flow occurred with a rate of 0.84 to 15.2 nL/s before treatment. After BisBlock or Clearfil SE Bond was used, the fluid movement was decreased by 39.8 to 89.6%.
Adhesives ; Capillaries ; Dentin ; Dentin Sensitivity ; Dentinal Fluid ; Glass ; Humans ; Hydrodynamics ; Nuts ; Oxalic Acid ; Resin Cements ; Tooth ; Track and Field