Molecular mechanism of hyperoxalic acid-induced arterial endothelial cell injury / 中华肾脏病杂志

Objective:To investigate the injury effect of hyperoxali acid on human arterial endothelial cells (HAECs) and its mechanism.Methods:HAECs were divided into intervention group and control group according to whether oxalic acid was used for intervention. The cells in the intervention group were stimulated with 30, 100, 200 and 300 μmol/L oxalic for different time. The effect of oxalic acid on the proliferation of HAECs was detected by MTT colorimetry. The change of cell cycle was analyzed by flow cytometry. The content of intracellular calcium was detected by fluorescence detection technology. The protein and mRNA expressions of cell cycle and anion transporter-related proteins were detected by Western blotting and fluorescence quantitative PCR. Besides, JAK2/STAT3 signaling pathway-related proteins were measured by Western blotting.Results:MTT colorimetry results showed that the intervention groups with high concentration of oxalic acid (100, 200, 300 μmol/L) could significantly inhibit the proliferation of HAECs, which was significantly different from the control group (all P<0.05). Fluorescence detection showed that the contents of intracellular calcium of HAECs in the intervention groups with high concentration of oxalic acid (100, 200, 300 μmol/L) were significantly higher than those in the control group after 48 hours ( P<0.05, P<0.001, P<0.001, respectively). Flow cytometry showed that the proportion of S phase of cells in the 200 μmol/L oxalic acid intervention group was significantly higher than that in the control group ( P<0.05). The results of Western blotting and PCR showed that the relative protein and mRNA expressions of anion transporter-related proteins slc26a1, slc26a5, slc26a11 in the intervention groups were higher than those in the control group (all P<0.05). Western blotting showed that the expression of p-JAK2 and p-STAT3 in the intervention groups after 24 hours were significantly higher than those in control group (all P<0.05). Conclusions:Hyperoxalic acid may enter HAECs through transporters slc26a1, slc26a5 and slc26a11 to inhibit cell proliferation and increase the intracellular calcium concentration. The mechanism may be through the activation of JAK2/STAT3 signaling pathway. Therefore, oxalic acid may be one of the uremic toxins leading to atherosclerosis.

Influence of desensitizers agents on the dentin bond strength after one-year water storage

Aim: Evaluate the effect of adhesives systems combined with desensitizer agents on the microtensile bond strength (µTBS) of a composite resin to dentin. Methods: Cervical dentin of thirty-two human molars were used to simulate hypersensitivity areas. The teeth were divided into four groups (n=8), according to the type of adhesive system and desensitizer agents. No desensitizer was used in the control (Clearfil SE Bond ­ CS). Two experimental groups were pretreated with either MS Coat Bond (MS) or Biofluorid 12 (BF) immediately prior to bonding with CS. The last group corresponded to Gluma Comfort Bond + Desensitizer (GC) application. After dentin treatments, a composite block was built-up on dentin surface and after 24 hours teeth were serially sectioned to obtain bonded bean specimens. Beams were stored in water for 24 hours or one year. Subsequently, the specimens were submitted to the µTBS test. Data were analyzed by two-way mixed ANOVA and Bonferroni's test (α = 0.05). Results: At 24 hours, there was no significant difference in µTBS among groups. However, at one year, dentin treated with MS or BF demonstrated significantly lower µTBS of CS to dentin compared to control and GC, which kept their µTBS stable. Conclusion: The effect of MS and BF desensitizer agents on the µTBS of CS to dentin did not reduce the µTBS at 24 hours, but it decreases significantly after one year

Anatomy, histochemistry and oxalic acid content of the leaflets of Averrhoa bilimbi and Averrhoa carambola

Abstract Averrhoa bilimbi L. and A. carambola L., Oxalidaceae, are the only two species of the genus Averrhoa L. Their leaves are widely used in folk medicine as an adjuvant in the treatment of diabetes. Some species may contain, for example, calcium oxalate crystals, which may lead to risk in its use when there is predisposition of individuals with reduced renal activity. Therefore, there are still few studies on the content of oxalic acid present in them, highlighting the importance of this investigation. The objective of this work was to conduct a comparative anatomical and histochemical study between the species and determining its content of oxalic acid. Semipermanent histological slides were prepared, following common plant anatomy procedures, for analysis of the leaflets in optical microscopy, polarization and scanning electron microscopy coupled with energy-dispersive X-ray spectrometry. To determine the total, soluble and insoluble oxalate content was used titration with potassium permanganate. The anatomical characterization allowed identifying the characters useful in the differentiation of the species. The histochemistry revealed the location of the metabolites. Chemical microanalyses demonstrated that the crystals are of calcium oxalate. A. carambola presented the highest levels of total oxalate and soluble oxalate. The study assists in the identification and quality control of A. bilimbi and A. carambola and brings new data on its oxalic acid content, which are important, in view of the medicinal use of the species.

Application of omics approaches in Sclerotinia sclerotiorum / 生物工程学报

Sclerotinia sclerotiorum is a typical necrotrophic plant pathogenic fungus that distributes worldwide and causes severe diseases on a broad-range of plant species. Studies on S. sclerotiorum have been mainly focused on biology and pathology. The development of high-throughput technologies enabled multi-omics approaches for systems biology. This review summarizes current researches on S. sclerotiorum and proposes systemic strategies for understanding its biology and pathology, to provide novel insights and references for further investigation on molecular biology and pathogenesis of the pathogenic fungi and the pathosystems.

Oxalic Acid from Lentinula edodes Culture Filtrate: Antimicrobial Activity on Phytopathogenic Bacteria and Qualitative and Quantitative Analyses

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.

Comparación de la conductancia hidráulica dentinaria, de acuerdo al tiempo de aplicación de desensibilizantes con base de oxalatos / Comparison of dentinal hydraulic conductance according to the application time of oxalate-based desensitizers

Introdución: se utilizó un modelo in vitro, para medir la conductancia hidráulica en discos de dentina humana, tratados con ácido oxálico por 15, 30 o 60 s y la mantención del efecto oclusivo, medido a los 7 y 14 días post aplicación. Métodos: 45 discos dentinarios de 1mm de grosor fueron obtenidos de terceros molares humanos libres de caries, en inoclusión, de pacientes entre 16 a 30 años de edad. Los discos fueron divididos en tres grupos de estudio (n = 15), dependiendo del tiempo de aplicación de una solución comercial de desensibilizante dentinario (DD) a base de oxalato (BisBlock®), que contiene ˂ 5% ácido oxálico pH 1,5-1,8: grupo A aplicación del agente por 15 s, grupo B aplicación por 30 s y grupo C por 60 s. La conductancia hidráulica de cada disco fue calculada posterior al grabado ácido, lo que corresponde a la máxima permeabilidad de dicho disco (100%), inmediatamente tras la aplicación del ácido oxálico y tras siete y 14 días de mantención en suero fisiológico.El análisis estadístico se hizo mediante test de ANOVA y post hoc de Games-Howell. Resultados: 35,46 ± 23,41% para el grupo A, 36,34 ± 15,88% para el grupo B y 24,99 ± 14,99% para el grupo C, por lo que la utilización de DD por 15, 30 ó 60 s generó una disminución en la permeabilidad que fue estadísticamente significativa (p ˂ 0,05). Conclusiones: el DD fue eficaz en reducir la conductancia hidráulica independiente del tiempo de aplicación, siendo esta reducción sólo temporal, ya que tras siete días la permeabilidad retorna a valores cercanos a los iniciales.

Introduction: an in vitro model was used to measure the hydraulic conductance in human dentin discs treated with oxalic acid for 15, 30 or 60 s maintaining the occlusive effect and measuring 7 and 14 days after application. Methods: 45 dentin discs measuring 1 mm thick were obtained from human third molars which were free of caries and in no occlusion; the samples were obtained from patients aged 16 to 30 years. Discs were sorted out into three study groups (n = 15) depending on the time of application of a commercial solution of oxalate-based dentin desensitizer (DD) (BisBlock®) which contains ˂ 5% oxalic acid of 1.5-1.8 pH: in group A the agent was applied for 15 s, in group B it was applied for 30 s, and in group C for 60 s. The hydraulic conductance of each disc was calculated after acid etching, which corresponds to the maximum permeability of discs (100%) after immediate application of oxalic acid, as well as seven and fourteen days of storage in saline solution. The statistical analysis was done with ANOVA test and post-hoc Games-Howell test. Results: 35,46 ± 23.41% in Group A, 36.34 ± 15.88% in Group B and 24.99 ± 14.99% in Group C, showing that the use of DD for 15, 30 or 60 s decreased permeability in a statistically significant manner (p <0.05). Conclusions: DD was effective in reducing hydraulic conductance regardless of application time, but this reduction was temporary only, since after seven days permeability returns to values close to those of baseline.

Analysis of auxiliary effect of oxalic acid Ai Sciplan auxiliary effect assisted with psychological intervention on coronary heart disease complicated with depression / 天津医药

Objective To investigate the curative effects of oxalic acid Ai Sciplan in assisting psychological therapy for coronary heart disease accompanied with depression. Methods A total of 136 patients of coronary heart disease with de?pression were randomly divided into control group and treatment group. The routine drug treatment was given to control group. Treatment group was given oxalic acid Ai Sciplan which is assisted by the psychological therapy based on the routine drug treatment schedule for six months. HAMD score before treatment, one-week, one-month, 3-month and 6-month after treatment were compared between two groups. Homocysteine (Hcy) and high sensitive C reactive protein (hs-CRP) levels were detected by circulating enzymatic method before treatment and 6-month after treatment. The WHO quality of life scale (WHOQOL-BREF) was used to assess the quality of life in two groups of patients. The improvements of angina and depressive symptoms were evaluated after 6-month treatment. The cardiovascular events were followed up in two groups. Re?sults HAMD scores significantly decreased after treatment in both groups (P < 0.05). HAMD scores at all different time points were significantly lower after treatment than those before treatment in treatment group. In control group, HAMD scores at different time points were also significantly lower after treatment than those before treatment, except time point of one week after treatment. The levels of Hcy and hs-CRP were decreased after treatment in two groups, and the levels were lower in treatment group than those of control group. Values of WHOQOL-BREF score, mental status, social relations and the sur?rounding environment scores were higher after treatment in both groups. Also they are higher in treatment group than that of control group. The angina and depressive symptoms were improved in treatment group. The incidences of angina, myocardial infarction, arrhythmia, heart failure, sudden cardiac death and other cardiovascular events were significantly lower in treat?ment group than those of control group (χ2=9.396, P<0.05). Conclusion Escitalopram oxalate combined with psychological therapy shows a significant beneficial effect and a better prognosis in the treatment of coronary heart disease and depression.

Observation of glutathione to prevent oxaliplatin-induced hepatic lesion / 药学实践杂志

Objective To observe the curative effect of magnesium isoglycyrrhizinate in prevention of liver injury induced by oxaliplatin .Methods The control group used oxaliplatin ,leucovorin ,5‐fluorouracil chemotherapy ,the treatment group were treated with oxaliplatin ,leucovorin ,5‐fluorouracil chemotherapy and simultaneous magnesium isoglycyrrhizinate were used at the same time .With 28 d for 1 course of treatment ,the treatment period consisted of 2‐4 courses ,observation of pa‐tients and the proportion of liver injury were made .Results In the control group ,liver injury incidence rate was 44 .4% ,the rate of injury was 19 .4% in treatment group ,there was significant difference between the two groups (P<0 .01) .Conclusion Magnesium isoglycyrrhizinate could be effective in prevention of oxaliplatin induced liver injury .

Reaction of common bean progenies to white mold derived from recurrent selection / Reação de progênies de feijão ao mofo branco derivadas de seleção recorrente

This study was realized with the objective of verifying the resistance to white mold of common bean progenies derived from recurrent selection for resistance to angular leaf spot. The plant material used was obtained from a program of recurrent selection, which was started by crossing seven lines with carioca grain type with ten sources of resistance to angular leaf spot according to the partial diallel scheme. To evaluate the resistance to white mold, it was verified the reaction of 17 parents plus 35 selected progenies, to oxalic acid. Huge heterogeneity among the parents was observed, showing that some of them have resistance alleles to white mold, and thus, there is a possibility of recombine these alleles through the recurrent selection and obtaining progenies with high levels of resistance. Even in initial cycles, some progenies exhibited resistance to white mold similar to the one of cultivar 'G-122', which presents good level of resistance to this disease. This leads to infer that the original population already had some level of physiological resistance for the reaction to absorption of oxalic acid, and also for resistance to angular leaf spot. Thus, among the selected progenies for resistance to angular leaf spot, grain type and high yield, at least four progenies have resistance to white mold similar to the source of resistance 'G-122'.

Este estudo foi realizado com o objetivo de verificar a resistência ao mofo branco de progênies de feijão, provenientes de seleção recorrente para resistência à mancha angular. O material vegetal utilizado foi obtido de um programa de seleção recorrente, iniciado com o intercruzamento entre sete linhagens com grãos tipo carioca e dez fontes de resistência à mancha angular no esquema dialelo parcial. Para avaliação da resistência ao mofo branco, foi verificada a reação desses 17 genitores mais as 35 progênies obtidas, ao ácido oxálico. Foi observada uma ampla variabilidade nos genitores, indicando que alguns possuem alelos de resistência ao mofo branco e, assim, há possibilidade de associação desses alelos no programa de seleção recorrente e obtenção de progênies com níveis superiores de resistência. As progênies que se apresentaram como mais resistentes foram MAV-1.7, MAV-3.36, MAVI-21 e MAVI-60. Mesmo em ciclos iniciais, algumas progênies apresentaram nota média de reação ao mofo branco semelhante à da cultivar 'G-122', que apresenta bom nível de resistência a essa doença. Isso leva a inferir que a população original utilizada já possuía algum nível de resistência fisiológica para a reação à absorção ao ácido oxálico e também para a resistência à mancha angular. Assim, entre as progênies selecionadas para a resistência à mancha angular, tipo de grão e produtividade, pelo menos quatro apresentam nível de resistência ao mofo branco semelhante à fonte de resistência 'G-122'.

Determination of trace oxalate and citrate in urine with capillary electrophoresis / 中华检验医学杂志

Objective To establish a method for determining oxalate and citrate in urine simultaneously by capillary electrophoresis.The components,the concentration and pH of the buffer solution,the separation voltage and the injection time on theseparation were studied in detail.Methods The separations were carried out using potassium dihydrogen phosphatebuffer ina fused-silica capillary tubeby capillary zone electrophoresis (CZE) and the detection were monitored by UV.24 h-urine samples from patients (n =5) and health control (n =5) were collected from Zhongshan Hospital of Fudan University for systematically validating the method developed.Results The optimized separations were carried out using a 50 mmol/L potassium dihydrogen phosphatebuffer solution (pH 6.5) in a fused-silica capillary tube of 50 cm × 50 μm I.D.Injections were made by using the pressure mode for 10 s at 34 mbar.The detections were monitored by a UV at 200 nm after samples were separated at avohage of 30 kV.Under the seconditions,urinary oxalate and citrate were separated completely within 5 min.The relative standard deviations of migration time and peak area within-run foroxalate and citrate were less than 1％ and 3.0％ and the betweenrun relative standard deviations were less than 2.0％ and 4.0％,respectively.The detection limits were 1 mg/L for both oxalate and citrate.The linearity ranges of oxalate and citrate were both 0-500 mg/L with the correlation coefficient between 0.999 5 and 0.995 4 (P ＜ 0.05),respectively.The average recoveries were 102.38％ for oxalate and 92.74％ for citrate.Conclusion This method is proved to be simple,sensitive and accurate,and also applied to determine oxalate and citrate in urine samples with satisfactory results.

Potassium extractability from soils of brazilian coffee regions / Extractabilidade de potássio de solos brasileiros cultivados com cafeeiro

Coffee, which is an important commodity for Brazil, is a highly K-demanding crop. Methods for recommending K fertilization to coffee crops in Brazil are based on the amount of exchangeable K. Mineralogical studies estimating K supply capacity from different soil fractions, from medium to long term, were performed in Brazilian soils, but very few studies have been carried out focusing on the use of successive chemical extractions. This study evaluated K release from whole soil, as well as clay, silt, and sand fractions of B-horizon samples of a basalt-derived Oxisol and a sienite-derived Ultisol, both representative soils from coffee regions of Minas Gerais State. Successive extractions (0 to 665 h) of K were performed with 10-3 mol L-1 of either citrate or oxalate at 1:10 solid:solution ratio. The cumulative results were compared with forms of K (exchangeable, non-exchangeable, and total) as measured by different extraction procedures. The results showed that exchangeable K was higher, and non-exchangeable as well as total K were lower in the whole soil fraction of the Oxisol, than the K forms extracted from the Ultisol. The clay fraction was the main source of K in the Oxisol whereas the silt fraction contributed most for K supply in the Ultisol. Citrate and oxalate extracted similar amounts of K from the Oxisol, which is probably related to the fact that most of its K supply came from the exchangeable form. Citrate caused a greater release of K (part of which being from the non-exchangeable form) from the Ultisol than did oxalate. This work showed that soil texture alone is not a good indicator of K supply capacity, since for the same particle size, the studied soils revealed different K extractability.

O café, importante mercadoria para o Brasil, é uma cultura que demanda grande quantidade de potássio (K). Os métodos de recomendação de fertilizantes potássicos para lavouras cafeeiras no Brasil são baseados na quantidade de K trocável no solo. Estudos mineralógicos que estimam a capacidade de suprimento de K em diferentes frações do solo, em médio e longo prazo, foram realizados em solos brasileiros, mas poucos foram realizados com foco em extrações sucessivas. No presente estudo, avaliou-se a liberação de K do solo e das frações argila, silte e areia de amostras do horizonte B de um Latossolo Vermelho distrófico e de um Nitossolo Háplico, ambos representativos de regiões cafeeiras de Minas Gerais. Extrações sucessivas de K , com tempos de agitação variando de 0 a 665 h, foram realizadas com 10-3 mol L-1 de citrato ou oxalato, na relação solo:solução de 1:10. Os resultados cumulativos foram comparados às formas de K (trocável, não-trocável e total) medidas por diferentes procedimentos de extração. Verificou-se que a concentração de K trocável foi maior e as concentrações de K não-trocável e total foram menores no Latossolo que as mesmas formas de K extraídas do Nitossolo. A fração argila foi a principal fonte de K do Latossolo, ao passo que a fração silte foi a que mais contribuiu para a liberação de K do Nitossolo. Citrato e oxalato extraíram quantidades similares de K do Latossolo, resultado este relacionado ao fato de que a maioria do suprimento de K foi extraída da forma trocável. O citrato extraiu mais K (parte na forma não-trocável) do Nitossolo que o oxalato. Observou-se, neste trabalho, que a textura do solo, isoladamente, não é uma boa indicação da capacidade do solo em suprir K para as plantas, visto que, para o mesmo tamanho de partículas, os solos estudados revelaram extratabilidade de K diferenciada.

Use of Aspergillus niger in the bioleaching of colemanite for the production of boric acid

Colemanite is one of the most important underground riches of Turkey, having approximately 60 percent of the world boron deposits, and it has a large portion in the deposits. In this study, chemical leaching and biological leaching methods were used for production of boric acid from colemanite (2CaO · 3B3O3 · 5H2O) (Emet-Kütahya, Turkey). Oxalic acid concentration, temperature, stirring time and solid-to-liquid ratio were taken as parameters in the chemical leaching process. It was found that the dissolution rate increases with increasing oxalic acid concentration and temperature but it decreases at higher solid-to-liquid ratios in the chemical leaching process. Using optimum conditions (d100 = 0.075 mm; 5 percent solids by weight; 0.55 M oxalic acid; 80 +/- 2 ºC leaching temperature; 150 rpm stirring speed; 90 min leaching time) for colemanite sample (28.05 percent B2O3) on chemical leaching with oxalic acid experiments, the calculated boric acid extraction efficiency from colemanite ore was 97.89 percent. Optimum conditions on bioleaching of Emet-Kütahya, Turkey colemanite ores using the fungus Aspergillus niger were found to be as follows: reaction temperature 25 +/- 2ºC; solid-to-liquid ratio 5 percent solids by weight; d100 = 0.075 mm; stirring speed 150 rpm; initial the fungus populations in the inocula about 3 x 10(7) cells/ml and reaction time 21 days. The calculated boric acid extraction efficiency from colemanite ore was 90.18 percent under the optimum conditions. Bioleachate contained 12.95 g/l B2O3, 6.60 g/l Ca and 0.087 g/l Mg. Compared with chemical leaching at 5 percent pulp density, the fungus was less efficient in the extraction of B2O3 from colemanite but the difference in the extraction yields between the two processes was less than 10 percent. Although bioleaching generally requires a longer period of operation compared to chemical leaching, these results suggest that bioleaching by A...

Avaliação da concentração de minerais e dos fatores antinutricionais fitato e oxalato em multimisturas da Região Metropolitana de Belo Horizonte/MG / Evaluation of mineral concentration and anti-nutritional factors phytate and oxalate in Multimix from the Metropolitan Region of the City of Belo Horizonte/MG

In this work, samples of Multimix, both for industrial use and prepared by the Child's Pastoral in different parts of the metropolitan region of Belo Horizonte / MG were analyzed for determining the concentration of phytates, oxalates and even the minerals K, Mg, Mn, Na, Zn, Fe and Ca. The results showed, in most cases, the concentration of minerals below the recommended daily intake for portions of multi-mixture used, 5 and 22.5g. The concentration of anti-nutritional factors was assessed by the molar ratios of phytate / Fe, phytate / Zn, phytate / Ca, phytate x Ca / Znand Ca / oxalate. The obtained values, in almost all cases > 1, associatedwith low concentration of minerals in the environment, suggest a low bioavailability of essential minerals, which reinforces the debate on the effectiveness of Multimix as a nutritional supplement.

En este trabajo, muestras de "multimistura" del tipo industrial y preparadas por la Pastoral del Niño en diferentes puntos de la región metropolitana de Belo Horizonte, Minas Gerais, Brasil, fueron analizadas para determinar la concentración de fitatos, oxalatos y los minerales K, Mg, Mn, Na, Zn, Fe y Ca. Los resultados mostraron, en la mayoría de los casos, una concentración de minerales abajo de la ingesta diaria recomendada, para las porciones diariasde "multimistura" ingerida: 5 y 22,5g. La concentración de factores antinutricionalesse evaluó mediante las relaciones molares defitato/Fe, fitato/Zn, fitato/Ca, fitato x Ca/Zn y Ca/oxalato. Los valores obtenidos, en casi todos los casos son mayores que la unidad (> 1), esto, asociado a una baja concentración de mineralesen el medio, permite suponer que hay baja biodisponibilidad de minerales esenciales, lo que refuerza el debate sobre la eficacia de la "multimistura" como suplemento nutricional.

Neste trabalho, amostras de multimistura do tipo industrial, preparadas pela Pastoral da Criança em diferentes pontos da região metropolitana de Belo Horizonte/MG, foram analisadas para determinação da concentração dos fatores antinutricionais fitato e oxalato e ainda dos minerais K, Mg, Mn, Na, Zn, Fe e Ca. Os resultados mostraram, na maior parte dos casos, concentração dos minerais abaixo do recomendado para ingestão diária nas porções utilizadas da multimistura, 5 e 22,5g. A concentração dos fatores antinutricionais foi avaliada através das razões molares fitato / Fe, fitato / Zn, fitato / Ca, fitato x Ca / Zn e Ca / oxalato. Os valores obtidos, em quase todos os casos > 1, associados à baixa concentração dos minerais no meio, sugerem uma baixa biodisponibilidade dos minerais essenciais, o que reforça o debate sobre a eficácia da multimistura como complemento nutricional.

Influence of oxalic acid and calcium oxalate monohydrate crystals on human renal tubular epithelial cells / 中华泌尿外科杂志

Objective To evaluate the toxic effects of oxalic acid and calcium oxalate monohydrate crystals on human renal tubular epithelial cells (HK-2) as well as the influence on cell protein expression. Methods Normal HK-2 cells were cultured in vitro and the culture medium was changed to serum-free medium after cell growth to confluence. Oxalic acid with different concentration wasthen added and the formation of crystals and their adherence to cells were observed microscopically. A Fourier infrared spectrometer (FT-IR) was used to analyze the crystal composition. The toxic effects of 1, 2, 5 and 10 mmol/L oxalic acid on HK-2 cells after incubation for 4, 12 and 24 h were detected with a CCK-8 kit. Changes of protein express of HK-2 cells were determined using the Bradford method. Results Crystal formation and adherence to cell surface could be microscopically observed in a few minutes after oxalic acid was added to the DMED medium containing Caz+. The composition of the crystals was revealed to be calcium oxalate monohydrate by FT-IR. Oxalic acid and calcium oxalate monohydrate presented a concentration-dependent toxic effect on HK-2 cells which was, however, not merely increased with time lasting. The quantity of protein expressed by HK-2 cells incubated with 1,2, 5 mmol/L oxalic acid for 12 h and that of control was 358±51, 365±43, 328±52 and 329±60 mg/L, respectively (all P>0. 05), while the quantity of protein was significantly smaller than that of control after the incubation of 10 mmol/L oxalic acid for 12 h (264±76 vs 329±60 mg/L,P<0. 05).Conclusion Oxalic acid and calcium oxalate monohydrate crystals have toxic effects on normal human HK-2 cells and cause changes in protein expression,which may play an important role in the formation of renal calculi.

NUTRITIONAL AND ENVIRONMENTAL FACTORS AFFECTING GROWTH OF SCLEROTINIA SCLEROTIORUM AND OXALIC ACID ACCUMULATION IN CULTURE / 微生物学通报

The effects of various media, pH, temperature and time course on mycelial growth (MG) of and oxalic acid accumulation (OA) by Sclerotinia sclerotiorum in the culture were studied. It was shown in an orthogonal experiment design (L_(16)4~3?2~6) that OA were significantly different (p