Arsenic accumulation in rice (Oryza sativa L.): Human exposure through food chain

Although human exposure to arsenic is thought to be caused mainly through arsenic-contaminated underground drinking water, the use of this water for irrigation enhances the possibility of arsenic uptake into crop plants. Rice is the staple food grain in Bangladesh. Arsenic content in straw, grain and husk of rice is especially important since paddy fields are extensively irrigated with underground water having high level of arsenic concentration. However, straw and husk are widely used as cattle feed. Arsenic concentration in rice grain was 0.5±0.02 mg kg-1 with the highest concentrations being in grains grown on soil treated with 40 mg As kg-1 soil. With the average rice consumption between 400 and 650 g/day by typical adults in the arsenic-affected areas of Bangladesh, the intake of arsenic through rice stood at 0.20-0.35 mg/day. With a daily consumption of 4 L drinking water, arsenic intake through drinking water stands at 0.2 mg/day. Moreover, when the rice plant was grown in 60 mg of As kg-1 soil, arsenic concentrations in rice straw were 20.6±0.52 at panicle initiation stage and 23.7±0.44 at maturity stage, whereas it was 1.6±0.20 mg kg-1 in husk. Cattle drink a considerable amount of water. So alike human beings, arsenic gets deposited into cattle body through rice straw and husk as well as from drinking water which in turn finds a route into the human body. Arsenic intake in human body from rice and cattle could be potentially important and it exists in addition to that from drinking water. Therefore, a hypothesis has been put forward elucidating the possible food chain pathways through which arsenic may enter into human body. © 2007 Elsevier Inc. All rights reserved

Binding of desloratadine and atenolol with bovine serum albumin and their in-vitro interactions

Objetivo: Unir atenolol, antagonista selectivo de los receptores β1, y desloratadina, antagonista de los receptores H1, a albúmina sérica bovina.Método: El análisis de la unión se analizó mediante diálisis de equilibrio utilizando ranitidina y diazepam como sondas específicas para el sitio I y sitio II respectivamenteResultados: Los resultados sugirieron dos conjuntos de constantes de asociación. Para el atenolol: constante de asociación con afinidad elevada (k1 = 5 x 10-5 M-1) con baja capacidad (n1 = 2) y constante de asociación con afinidad baja (k2 = 5 x 10-5 M-1) con alta capacidad (n2 = 5), mientras que para la desloratadina: constante de afinidad de asociación elevada (k1 = 45 x 10-5 M-1) con baja capacidad (n1 = 1,3) y constante de afinidad de asociación baja (k2= 5 x 10-5 M-1) con alta capacidad (n2 = 2,5), a un pH 7,4 y 27 °C. Tras la administración conjunta de atenolol y desloratadina en presencia o ausencia de ranitidina o diazepam, la desloratadina provocó la liberación del atenolol de su sitio de unión a la albúmina sérica bovina, provocando una disminución de la unión del atenolol a la albúmina sérica bovina. La fracción libre de atenolol incrementó del 84,1% al 99% y la concentración de la desloratadina de 0 x 10-5 M a 14 x 10-5 M. En presencia de diazepam como sonda específica para el sitio II, la desloratadina incrementó la fracción libre de atenolol del 0,45% to 14,3%.Conclusión: Los datos obtenidos indican la interacción de concentraciones elevadas de desloratadina a los sitios de unión de la albúmina sérica bovina modificando las propiedades farmacocinéticas del atenolol.Aims: The binding of atenolol a selective β1 receptor antagonist and desloratadine, an H1 receptor antagonist, to bovine serum albumin.Methods: The analysis of binding was studied by equilibrium dialysis method (ED) using ranitidine and diazepam as site-1 and site-2 specific probe, respectively.Results: The study suggested two sets of association constants, for atenolol: high affinity association constant (k1 = 5 x 10-5 M-1) with low capacity (n1 = 2) and low affinity association constant (k2 = 2.5 x 10-5 M-1) with high capacity (n2 = 5), while for desloratadine: high affinity association constant (k1 = 45 x 10-5 M-1) with low capacity (n1 = 1.3) and low affinity association constant (k2 = 5 x 10-5 M-1) with high capacity (n2 = 2.5) at pH 7.4 and 27 °C. During concurrent administration of atenolol and desloratadine in presence or absence of ranitidine or diazepam, desloratadine causes the release of atenolol from its binding site on BSA resulting reduced binding of atenolol to BSA. The increment in free fraction of atenolol was from 84.01% to 99 % upon the addition of increased concentration of only desloratadine at a concentration of 0 x 10-5 M to 14 x 10-5 M. In presence of diazepam as site-II specific probes, desloratadine further increases the free fraction of atenolol was from 0.45% to 14.3%.Conclusion: These data were indicative for the interaction of higher concentration of desloratadine at the binding sites on BSA changing the pharmacokinetics properties of atenolol

Binding of desloratadine and atenolol with bovine serum albumin and their in-vitro interactions

Objetivo: Unir atenolol, antagonista selectivo de los receptores β1, y desloratadina, antagonista de los receptores H1, a albúmina sérica bovina.Método: El análisis de la unión se analizó mediante diálisis de equilibrio utilizando ranitidina y diazepam como sondas específicas para el sitio I y sitio II respectivamenteResultados: Los resultados sugirieron dos conjuntos de constantes de asociación. Para el atenolol: constante de asociación con afinidad elevada (k1 = 5 x 10-5 M-1) con baja capacidad (n1 = 2) y constante de asociación con afinidad baja (k2 = 5 x 10-5 M-1) con alta capacidad (n2 = 5), mientras que para la desloratadina: constante de afinidad de asociación elevada (k1 = 45 x 10-5 M-1) con baja capacidad (n1 = 1,3) y constante de afinidad de asociación baja (k2= 5 x 10-5 M-1) con alta capacidad (n2 = 2,5), a un pH 7,4 y 27 °C. Tras la administración conjunta de atenolol y desloratadina en presencia o ausencia de ranitidina o diazepam, la desloratadina provocó la liberación del atenolol de su sitio de unión a la albúmina sérica bovina, provocando una disminución de la unión del atenolol a la albúmina sérica bovina. La fracción libre de atenolol incrementó del 84,1% al 99% y la concentración de la desloratadina de 0 x 10-5 M a 14 x 10-5 M. En presencia de diazepam como sonda específica para el sitio II, la desloratadina incrementó la fracción libre de atenolol del 0,45% to 14,3%.Conclusión: Los datos obtenidos indican la interacción de concentraciones elevadas de desloratadina a los sitios de unión de la albúmina sérica bovina modificando las propiedades farmacocinéticas del atenolol.Aims: The binding of atenolol a selective β1 receptor antagonist and desloratadine, an H1 receptor antagonist, to bovine serum albumin.Methods: The analysis of binding was studied by equilibrium dialysis method (ED) using ranitidine and diazepam as site-1 and site-2 specific probe, respectively.Results: The study suggested two sets of association constants, for atenolol: high affinity association constant (k1 = 5 x 10-5 M-1) with low capacity (n1 = 2) and low affinity association constant (k2 = 2.5 x 10-5 M-1) with high capacity (n2 = 5), while for desloratadine: high affinity association constant (k1 = 45 x 10-5 M-1) with low capacity (n1 = 1.3) and low affinity association constant (k2 = 5 x 10-5 M-1) with high capacity (n2 = 2.5) at pH 7.4 and 27 °C. During concurrent administration of atenolol and desloratadine in presence or absence of ranitidine or diazepam, desloratadine causes the release of atenolol from its binding site on BSA resulting reduced binding of atenolol to BSA. The increment in free fraction of atenolol was from 84.01% to 99 % upon the addition of increased concentration of only desloratadine at a concentration of 0 x 10-5 M to 14 x 10-5 M. In presence of diazepam as site-II specific probes, desloratadine further increases the free fraction of atenolol was from 0.45% to 14.3%.Conclusion: These data were indicative for the interaction of higher concentration of desloratadine at the binding sites on BSA changing the pharmacokinetics properties of atenolol

Interaction of palmitic acid with losartan potassium at the binding sites of bovine serum albumin

The binding of losartan potassium, an angiotensin II receptor antagonist, to bovine serum albumin was studied by equilibrium dialysis method (ED) in presence or absence of palmitic acid. The study was carried out using ranitidine and diazepam as site-1 and site-2 specific probe, respectively. Different analysis of binding of losartan to bovine serum albumin suggested two sets of association constants: high affinity association constant (k1 = 11.2 x 105 M-1) with low capacity (n1 = 2) and low affinity association (k2 = 2. 63 x 105 M-1) constant with high capacity (n2 = 10) at pH 7.4 and 27°C. During concurrent administration of palmitic acid and losartan potassium in presence or absence of ranitidine or diazepam, it was that found that palmitic acid causes the release of losartan potassium from its binding site on BSA resulting reduced binding of losartan potassium to BSA. The increment in free fraction of losartan potassium was from 13.1% to 47.2 % upon the addition of increased concentration of only palmitic acid at a concentration of 0 x 10-5 M to 16 x 10-5 M. In presence of ranitidine or diazepam as site specific probes, palmitic acid further increases the free fraction of losartan potassium were from 22.8% to 53.4% and 35.3 to 65.5%, respectively. This data provided the evidence of interaction of higher concentration of palmitic acid at the binding sites on BSA changing the pharmacokinetics properties of losartan potassium

Genetic Dissection of Sympatric Populations of Brown Planthopper, Nilaparvata lugens (Stål), Using DALP-PCR Molecular Markers

Direct amplified length polymorphism (DALP) combines the advantages of a high-resolution fingerprint method and also characterizing the genetic polymorphisms. This molecular method was also found to be useful in brown planthopper, Nilaparvata lugens species complex for the analysis of genetic polymorphisms. A total of 11 populations of Nilaparvata spp. were collected from 6 locations from Malaysia. Two sympatric populations of brown planthopper, N. lugens, one from rice and the other from a weed grass (Leersia hexandra), were collected from each of five locations. N. bakeri was used as an out group. Three oligonucleotide primer pairs, DALP231/DALPR′5, DALP234/DALPR′5, and DALP235/DALPR′5 were applied in this study. The unweighted pair group method with arithmetic mean (UPGMA) dendrogram based on genetic distances for the 11 populations of Nilaparvata spp. revealed that populations belonging to the same species and the same host type clustered together irrespective of their geographical localities of capture. The populations of N. lugens formed into two distinct clusters, one was insects with high esterase activities usually captured from rice and the other was with low esterase activities usually captured from L. hexandra. N. bakeri, an out group, was the most isolated group. Analyses of principal components, molecular variance, and robustness also supported greatly to the findings of cluster analysis

Evaluation of two concepts of fertilization for wheat in a calcareous soil of Bangladesh

Two popular concepts of soil fertilization, basic cation saturation ratio (BCSR) and sufficiency level of available nutrients (SLAN), were tested on a calcareous soil (Aeric haplaquept) during 1995-1996 at the Bangladesh Rice Research Institute (BRRI) Regional Station Rajshahi using wheat as a test crop. According to BCSR concept the soil was deficient in potassium (K) and according to SLAN concept it was deficient in phosphorus (P), respectively. Potassium dose of 120 kg ha-1 [to attain 2% saturation of total cation exchange capacity (CEC) according to BCSR] along with other two doses (0 and 60 kg K ha-1) and P dose of 50 kg ha-1 (to attain available P at sufficiency level) along with other two doses (0 and 100 kg P ha-1) were compared in a randomized complete block design. The application of 50 kg P ha-1 significantly increased plant height, spikes m-2, grains per spike, grain and straw yields of wheat over 0 kg P ha-1 with or without K but increasing P dose from 50 to 100 kg P ha-1 did not give additional yields. The agronomic parameters and yields were not affected significantly by K application. Similar results were also observed in nutrient content and nutrient uptake. Thus, SLAN concept appeared as an effective tool for fertilizer recommendation for the calcareous soil while BCSR gave no apparent result there

Arsenic accumulation in rice (Oryza sativa L.): Human exposure through food chain

金沢大学大学院自然科学研究科物質情報解析Although human exposure to arsenic is thought to be caused mainly through arsenic-contaminated underground drinking water, the use of this water for irrigation enhances the possibility of arsenic uptake into crop plants. Rice is the staple food grain in Bangladesh. Arsenic content in straw, grain and husk of rice is especially important since paddy fields are extensively irrigated with underground water having high level of arsenic concentration. However, straw and husk are widely used as cattle feed. Arsenic concentration in rice grain was 0.5±0.02 mg kg-1 with the highest concentrations being in grains grown on soil treated with 40 mg As kg-1 soil. With the average rice consumption between 400 and 650 g/day by typical adults in the arsenic-affected areas of Bangladesh, the intake of arsenic through rice stood at 0.20-0.35 mg/day. With a daily consumption of 4 L drinking water, arsenic intake through drinking water stands at 0.2 mg/day. Moreover, when the rice plant was grown in 60 mg of As kg-1 soil, arsenic concentrations in rice straw were 20.6±0.52 at panicle initiation stage and 23.7±0.44 at maturity stage, whereas it was 1.6±0.20 mg kg-1 in husk. Cattle drink a considerable amount of water. So alike human beings, arsenic gets deposited into cattle body through rice straw and husk as well as from drinking water which in turn finds a route into the human body. Arsenic intake in human body from rice and cattle could be potentially important and it exists in addition to that from drinking water. Therefore, a hypothesis has been put forward elucidating the possible food chain pathways through which arsenic may enter into human body. © 2007 Elsevier Inc. All rights reserved

Towards a target label-free suboptimum oligonucleotide displacement-based detection system

A novel method for the future development of label-free DNA sensors is proposed here. The approach is based on the displacement of a labelled suboptimum mutated oligonucleotide hybridised with the immobilised biotin-capture probe. The target fully complementary to the biotin-capture probe can displace the labelled oligonucleotide causing a subsequent decrease of the signal that verifies the presence of the target. The decrease of signal was demonstrated to be proportional to the target concentration. A study of the hybridisation of mutated and complementary labelled oligonucleotides with an immobilised biotin-capture probe was carried out. Different kinetic and thermodynamic behaviour was observed for heterogeneous hybridisation of biotin-capture probe with complementary or suboptimum oligonucleotides. The displacement method evaluated colourimetrically achieved the objective of decreasing the response time from 1 h for direct hybridisation of 19-mer oligonucleotides in the direct enzyme-linked oligonucleotide assay (ELONA) to 5 min in the case of displacement detection in the micromolar concentration range