Effect of Extraction Variables on the Biodegradable Chelant-Assisted Removal of Toxic Metals from Artificially Contaminated European Reference Soils

Development of aminopolycarboxylate chelants (APCs) having enhanced biodegradability is gaining increasing focus to replace the EDTA and its homologs with those used widely for the ex situ treatment of contaminated soils and are potential eco-threats. The paper reports the chelant-assisted extraction of the toxic metals (Cd, Cu, Pb, and Zn) from the metal-spiked European reference soils (Eurosoil 1 and Eurosoil 4) using biodegradable APCs, namely EDDS, GLDA, and HIDS. The effects of chelant-to-metal molar ratio, solution pH, and metal/chelant stability constants were evaluated, and compared with that of EDTA. The selectivity aptitude of the biodegradable chelants towards the toxic metals was assumed from the speciation calculations, and a proportionate correlation was observed at neutral pH. Pre- and post-extractive solid phase distributions of the target metals were defined using the sequential extraction procedure and dissolution of metals from the theoretically immobilized fraction was witnessed. The effect of competing species (Al, Ca, Fe, Mg, and Mn) concentrations was proven to be minimized with an excess of chelant in solution. The highlight of the outcomes is the superior decontamination ability of GLDA, a biodegradable APC, at minimum chelant concentration in solution and applicability at a wide range of pH environments.     

Calcitriol Treatment Attenuates Uric Acid-Induced Kidney Injury via Super Oxide Dismutase-1 (SOD-1) Upregulation and Fibrosis Reduction

Background:Hyperuricemia induces nephropathy through the mediation of oxidative stress, tubular injury, inflammation, and fibrosis. The high uric acid level is associated with the reduction of vitamin D levels. However, the reno-protective effects of this vitamin in hyperuricemia condition remain unknown. This study aimed to elucidate calcitriol treatment in a uric acid-induced hyperuricemia mice model. Methods:Uric acid (125 mg/kg BW) was administered intraperitoneally for 7 (UA7) and 14 (UA14) days. Calcitriol (0.5 g/kg BW) was intraperitoneally injected for the following seven days, after 14 days of uric acid induction (UA14VD7 group). The control group received NaCl 0.9%, by the same route. Serum creatinine was measured using calorimetric method, and uric acid levels were assessed using enzymatic calorimetric assay. Tubular injury and fibrosis were assessed using PAS and Sirius red staining. RT-PCR and qRT-PCR were carried out for the analyses of SOD-1, Collagen-1, and TGF-1 mRNA expression in the kidney. Immunostaining of SOD-1 was performed to detect its expression in the kidney. Results:Uric acid and creatinine levels markedly increased in UA14 groups, followed by an exacerbation of tubular injury. RT-PCR revealed the upregulation of Collagen-1 and TGF-1, along with the downregulation of SOD-1. Calcitriol treatment attenuated the injury with reducing uric acid and creatinine levels, as well as tubular injury. This was associated with lower Collagen-1 and TGF-1 mRNA expression compared to the UA7 and UA14 groups. SOD-1 was upregulated in epithelial cells in the UA14VD7 group. Conclusion:Calcitriol treatment after uric acid induction may attenuate kidney injury through upregulation of SOD-1 and downregulation of Collagen-1 and TGF-1 gene expression. Key Words: Fibrosis, Hyperuricemia, Kidney injury, Superoxide dismutase-1, Vitamin D     

Influence of phosphine on hatching of Cryptolestes ferrugineus (Coleoptera: Cucujidae), Lasioderma serricorne (Coleoptera: Anobiidae) and Oryzaephilus surinamensis (Coleoptera: Silvanidae)

The hatching and mortality response of 0- to 48-h-old eggs of field strains of the stored-product insects Cryptolestes ferrugineus (Stephens), Lasioderma serricorne (F) and Oryzaephilus surinamensis (L) following phosphine fumigation for 24, 48 or 120 h at 27 (+/- 2) degrees C was investigated. Hatching was delayed and reduced in the first few days in a phosphine-resistant strain of C ferrugineus that was treated with 2.0-7.0 mg litre(-1) doses for 48 h (5-80% mortality) and with 1.0-2.0 mg litre(-1) for 120 h (44-84% mortality). In both the exposures there were significant increases in hatching on later days when compared with the corresponding controls. Developmental delay was, however, not evident in susceptible strains of C ferrugineus, L serricorne and O surinamensis that were exposed to phosphine for 24 h.     

Soil organic matter fractionation as a tool for predicting nitrogen mineralization in silty arable soils

After decades of searching for a practical method to estimate the N mineralization capacity of soil, there is still no consistent methodology. Indeed it is important to have practical methods to estimate soil nitrogen release for plant uptake and that should be appropriate, less time consuming, and cost effective for farmers. We fractionated soil organic matter (SOM) to assess different fractions of SOM as predictors for net N mineralization measured from repacked (disturbed) and intact (undisturbed) soil cores in 14 weeks of laboratory incubations. A soil set consisting of surface soil from 18 cereal and root‐cropped arable fields was physically fractionated into coarse and fine free particulate OM (coarse fPOM and fine fPOM), intra‐microaggregate particulate OM (iPOM) and silt and clay sized OM. The silt and clay sized OM was further chemically fractionated by oxidation with 6% NaOCl to isolate an oxidation‐resistant OM fraction, followed by extraction of mineral bound OM with 10% HF (HF‐res OM). Stepwise multiple linear regression yielded a significant relationship between the annual N mineralization (kg N/ha) from undisturbed soil and coarse fPOM N (kg N/ha), silt and clay N (kg N/ha) and its C:N ratio (R² = 0.80; P < 0.01). The relative annual N mineralization (% of soil N) from disturbed soils was related to coarse fPOM N, HF‐res OC (% of soil organic carbon) and its C:N ratio (R² = 0.83; P < 0.01). Physical fractions of SOM were thus found to be the most useful predictors for estimating the annual N mineralization rate of undisturbed soils. However, the bioavailability of physical fractions was changed due to the disturbance of soil. For disturbed soils, a presumed stable chemical SOM fraction was found to be a relevant predictor indicating that this fraction still contains bio‐available N. The latter prompted a revision in our reasoning behind selective oxidation and extraction as tools for characterizing soil organic N quality with respect to N availability. Nonetheless, the present study also underscores the potential of a combined physical and chemical fractionation procedure for isolating and quantifying N fractions which preferentially contribute to bulk soil N mineralization. The N content or C:N ratio of such fractions may be used to predict N mineralization in arable soils.     

Nitrogen mineralization in sub‐tropical paddy soils in relation to soil mineralogy,management, pH,carbon, nitrogen and iron contents

The nitrogen (N) requirement for paddy rice cultivated in Bangladesh amounts to approximately 80 kg N ha^?1. Lack of knowledge on N mineralization from soil organic matter leads farmers to meet this N requirement exclusively by costly mineral fertilizers, which have typically an efficiency of less than 40%. We assessed to what extent routinely analysed soil properties (N and carbon (C), texture, pH, extractable iron (Fe), aluminium (Al) and manganese (Mn), soil mineralogy and length of the annual inundation period) are able to predict net aerobic and anaerobic N mineralization in paddy soils. Both soil N and C correlated positively with the aerobic but not with the anaerobic N mineralization rate. Instead, relative anaerobic N mineralization showed a significant negative correlation with soil N content. We observed no significant influence of clay mineralogy on soil N mineralization. Aerobic but not anaerobic N mineralization increased with length of the annual inundation period while the proportion of the soil N that was mineralized during 120 days decreased. The large clay content of fields that are inundated for 9–10 months annually explains the co‐occurrence of large soil N contents and relatively small N mineralization rates in these fields. However, variation in texture did not explain variation in N mineralization of soils with inundation periods of 3–8 months. Instead, the anaerobic N mineralization correlated positively with Na pyrophosphate‐extractable Fe and negatively with pH (both at P < 0.01). Thus, pH and Fe content, rather than soil N content, clay mineralogy or texture, explained the substantial variation in anaerobic N mineralization of paddy soils in Bangladesh inundated for 3–8 months. It is not known if these relationships between net evolution of ammonium in soil and pH and Fe content are causal or indirect. Elucidation of these mechanisms would greatly further our comprehension of the biochemistry of the young ‘floodplain soils' with relatively low content of pedogenic oxides throughout southeast Asia.     

Use of egg custard augmented with cod liver oil and Moina micrura on production of freshwater prawn postlarvae

Use of egg custard augmented with cod liver oil (CLO) fed during the day, and of an overnight feed with Moina micrura, were evaluated in terms of its effects on production of freshwater prawn (Macrobrachium rosenbergii) postlarvae (PL). Four levels of CLO (0, 1,3 and 5%) were tested. Significantly higher mean (sd) productions, ranging from 11.27 (1.16) to 13.02 (1.70) PL l^–1, were obtained for larvae fed egg custard enriched with CLO compared with that of 7.83 (1.58) PLl^–1 for larvae fed egg custard without CLO. The development and survival of larval stages were also higher for the CLO diets. The -3 highly unsaturated fatty acid (HUFA) in egg custard increased with increasing CLO level (0–5%). The fatty acid composition of postlarvae reflected the composition of the diet.     

Effect of high protein rice on nitrogen retention and growth of preschool children on a rice-based diet

The effect of high protein milled rices (IR480-5-9 and IR2153-338-3, 10% protein) on the nitrogen retention and growth of preschool Indian children was assessed in two feeding trials in a residential home. The children were offered, ad libitum, a rice-based diet in four meals daily without vitamin and mineral supplement. The children in the experimental group were given the high protein rice; those in the control group were given a local rice (7% protein). The groups had similar percent apparent digestibility and retention of dietary nitrogen. Statistically significant differences in increase in height and weight between the two groups were not consistently observed at the end of 4.5 to 5 months or 1 year. Possible factors contributing to these results are discussed.     

Technical Efficiency of Shrimp Farming in Bangladesh: An Application of the Stochastic Production Frontier Approach

This study estimates the levels and determinants of farm‐level technical efficiency of shrimp farmers, using the stochastic production frontier function involving a model for technical inefficiency effects. A sample of 90 brackish water shrimp farms were surveyed in the region of Shyamnagar Upazila of the Satkhira District, Bangladesh, to study their economic efficiencies. Data were collected, using a questionnaire survey from September to October 2011. The mean technical efficiency level of the shrimp farmers was estimated at 82%, and thus, farmers operate 18% below the production frontier. The results suggest that the inefficiency effect is significant, and that education, age, non‐farm income and distance of the farm are significant determinants of technical inefficiency. By operating at full technical efficiency levels, shrimp production can increase from the current yield of 225.56 to 265.28 kg/ha. Besides improving technical efficiency, technological progress and extension services (such as dissemination of proper information of the technological practices and further adoption of technological practices) can also contribute to increased shrimp production levels. Finally, quality feed and fingerling at affordable prices need to be ensured to further promote shrimp production.     

Protein digestibility-corrected amino acid scores (PDCAAS) for soy protein isolates and concentrate: criteria for evaluation

Protein quality, as determined by the PDCAAS method, is a measure of a protein's ability to provide adequate levels of essential amino acids for human needs. PDCAAS is calculated using an amino acid profile and true digestibility of a food protein. Soy protein is recognized as a high quality plant protein, but published PDCAAS values may vary based on the soy protein ingredient as well as the reproducibility and accuracy of the testing methods. Comparison of PDCAAS values for four differently processed soy ingredients, including three isolated soy proteins (ISP) and one soy protein concentrate (SPC), was made using two different laboratories with evaluation of the impact of the reproducibility and accuracy of amino acid profiles. PDCAAS calculations, using amino acid values from one laboratory, yielded a truncated PDCAAS of 1.00 for all four ingredients, while a second laboratory provided statistically significantly lower scores (0.95-1.00). We conclude that analytical method error can be a significant contributor to PDCAAS differences and can be mitigated by the application of amino acid nitrogen recovery correction factors.     

The effect of a perennial cover crop on net soil N mineralization and microbial biomass carbon in coconut plantations in the humid tropics

The decrease in soil fertility in agroecosystems due to continuous harvesting, loss of fine soil and oxidation of soil organic carbon (SOC) is well known. This study evaluates for a humid tropical climate in South Andaman Island, India, the impact of a 15-yr old Pueraria cover crop (CC) under a coconut plantation, with and without phosphorus (P) application, on the soil N mineralization rate (NMR), the mineral N pool (NH₄⁺-N and NO₃⁻-N), microbial biomass carbon (MB-C) and SM under four treatments, (1) no cover crop (NCC), (2) no cover crop + phosphorus (NCC+P), (3) CC, and (4) cover crop + phosphorus (CC+P) during three seasons, wet (May–October), post-wet (November–January) and dry (February–April). The NCC treatment served as a control. In addition, an ex-situ experiment was conducted to verify the effect of P application on NMR and MB-C under 100% field capacity (FC), 50 and 25% FC representing the different seasons. The NMR, mineral N pool and MB-C increased by 37, 46 and 41%, respectively under the CC compared to the control. SOC and fine soil particles were also greater under the CC by 41 and 461%, respectively, compared to the control. The application of P to the CC increased soil N mineralization, the mineral N pool and MB-C by 33, 16 and 14%, respectively. The amount of mineralized N was greater under the CC and CC+P treatments by 39 and 73%, respectively than the control. The ex-situ experiment showed that the P application increased NMR and MB-C, but the increases were highest in the 50% FC and lowest in 100% FC. It is proposed for the humid tropics that a CC could be used for enhancing SOC and increasing soil N mineralization under coconut plantations and other similar agroecosystems.