The effect of trace minerals on the stability of retinol acetate, cholecalciferol and selenomethionine stability within premixes

This study compared the effect of an organic proteinate mineral source and an inorganic sulphate mineral source in relation to their effect on the stability of retinol acetate and cholecalciferol within simulated premixes, while comparing the stability of two different selenomethionine (SeMet) sources (selenium enriched yeast (SeYeast) and the chemically synthesised L-SeMet) in the presence of inorganic sulphate mineral sources within simulated premixes. Four vitamin-trace mineral premixes, two containing organic trace mineral sources in the form of proteinates and two containing inorganic trace mineral sources in the form of sulphates, were formulated so that, when added to a complete broiler feed at the appropriate inclusion rates, they contained the same amount of retinol acetate and cholecalciferol and varying levels of trace minerals (National Research Council recommended level, commonly used industry level or a reduced inclusion level). The two SeMet-trace mineral premixes were formulated to contain commonly used industry levels of vitamins and trace minerals. The two SeMet-trace mineral premixes differed in the source of SeMet. One premix contained chemically synthesised L-SeMet while the other contained SeYeast. The vitamin content of the four vitamin-trace mineral premixes was analysed after 14 and 84 days in storage by ultra-high performance liquid chromatography and the amount present within each of the premixes was compared to the quantity determined prior to storage. In general, the premixes formulated with the sulphate trace mineral source were found to have higher losses of retinol acetate and cholecalciferol than those formulated with the proteinate trace mineral source. The inclusion of the proteinate minerals at both National Research Council and reduced inclusion levels significantly (P≤0.05) increased the stability of both the vitamins when compared to the inorganic sulphate mineral sources included at commonly used industry levels. The SeMet content of the two SeMet-trace mineral premixes was analysed after 49 days in storage by high performance liquid chromatography – inductively coupled plasma mass spectrometry and the amount of SeMet present within each of the samples was compared to the quantity determined prior to storage. SeMet present within the SeYeast was found to be significantly more stable (P≤0.05) than the chemically synthesised L-SeMet.

Direct sulphate-TOR signalling controls transcriptional reprogramming for shoot apex activation in Arabidopsis

Photosynthetic plants play a primary role for the global sulphur cycle in the earth ecosystems by reduction of inorganic sulphate from the soil to organic sulphur-containing compounds. How plants sense and transduce the sulphate availability in soil to mediate their growth remains largely unclear. The target of rapamycin (TOR) kinase is an evolutionarily conserved master regulator of nutrient sensing and metabolic signalling to control cell proliferation and growth in all eukaryotes. Here, we discovered that inorganic sulphate exhibits higher potency than organic cysteine and glutathione for activation of TOR and cell proliferation in the leaf primordium to promote true leaf development in Arabidopsis. Chemical genetic analyses further revealed that this sulphate activation of TOR is independent of the sulphate-assimilation process and glucose-energy signalling. Significantly, tissue specific transcriptome analyses uncovered previously unknown sulphate-orchestrating genes involved in DNA replication, cell proliferation, autophagy and various secondary metabolism pathways, which are completely depending on TOR signalling. Systematic comparison between the sulphate- and glucose-TOR controlled transcriptome further revealed that, as the central growth integrator, TOR kinase can sense different upstream nutrient signals to control both shared and unique transcriptome networks, therefore, precisely modulate plant proliferation, growth and stress responses.

Impact of Chelated or Inorganic Manganese and Zinc Applications in Closed Hydroponic Bean Crops on Growth, Yield, Photosynthesis, and Nutrient Uptake

In this study, we investigated the effect of individual and combined applications of manganese (Mn) and zinc (Zn) chelates on common bean grown in hydroponics (nutrient film technique—NFT) on physiological and agronomical responses. Inorganic sulphate forms of Mn and Zn were compared to their synthetic chelate forms, in the replenishment nutrient solution (RNS). Nutrient (N, P, K, Ca, Mg, Fe, Mn, Zn and Cu) to water uptake ratios (termed uptake concentrations; UCs), growth, pods yield and quality, photosynthetic parameters and tissue nutrient status were evaluated in different cropping seasons (spring-summer and autumn-winter crops). Mean UCs of nutrients ranged as follows: 10.1–12.4 (N), 0.8–1.0 (P), 5.2–5.6 (K), 1.8–2.2 (Ca), 0.9–1.0 (Mg) mmol L−1; 12.2–13.4 (Fe), 5.2–5.6 (Mn), 4.4–4.9 (Zn), 0.9–1.0 (Cu) μmol L−1. Tissue macronutrient status remained unaffected in both seasons, however, Mn chelates in the RNS affected Fe within plants. Pod yield and quality, growth, photosynthesis and water uptake did not differ among treatments; however, seasonal variations are presented. Results suggest that the chelate forms of Mn and/or Zn in the refill solution for NFT-grown beans do not lead to any changes, adding superiority in the yield, photosynthesis, and nutritional status of the crops compared to their mineral forms.

Solar irradiation as an alternative bleaching process for agar extracted from Gracilariopsis heteroclada in Iloilo, Philippines

The current industrial practice of using chemical bleach to achieve the pure white colour of agar is deleterious to both human and environmental health. This study evaluates the potential of solar irradiation as an alternative bleaching process for agar extracted from Gracilariopsis heteroclada in Iloilo, Philippines. The physico-chemical properties of agar obtained from alkaline-treated seaweed after exposure to different bleaching conditions (e.g. solar irradiation, hypochlorite solution, and ultraviolet and fluorescent lights) were examined and compared with commercial bacteriological agar. Photobleaching through solar irradiation produced agar with superior gel strength (1038.61 g cm−2), high 3,6-anhydrogalactose content (41.44%) and low total inorganic sulphate content (1.87%) without compromising agar yield (19.37%). Solar irradiation offers very promising results as a simple, low-cost, environmentally friendly alternative to the chlorine bleaching process for agar extraction.

Serum Sulphate Levels in Hemodialysis Patients

Objective. Sulphur, similar to phosphorus, is easily attached to organic compounds. The inadequate elimination of sulphate may cause high sulphate concentrations in hemodialysis (HD) patients because sulphate is low in free form in plasma. Although we are well aware of the accumulation of phosphorus in chronic dialysis patients, we do not have an adequate knowledge database about the sulphur compounds. This study was designed to determine the level of sulphate in hemodialysis patients. Materials and Methods. Ninety-four prevalent HD patients and 33 patients without renal failure were included in the study. The serum inorganic sulphate levels were measured by turbidimetric technique. Moreover, the serum level of urea, creatinine, albumin, calcium, phosphorus, and parathyroid hormone concentrations was simultaneously recorded. Results. Mean levels of plasma sulphate were significantly higher (0.56 ± 0.17 mM vs 0.31 ± 0.13 mM, p<0.001) in HD patients. Serum sulphate level correlated with patient’s age, serum albumin, serum BUN and creatinine, and serum phosphorus level in HD patients. Serum sulphate levels were not associated with serum parathyroid hormone levels. Conclusion. Serum sulphate levels were approximately twofold higher in HD patients than in the normal control group. Inorganic sulphate does not seem to accumulate in long-term dialysis patients, and mild increased serum levels of sulphate has no poor clinical outcome in these patients.

Changes in soil extractable sulphate under field fallow conditions after application of three contrasting sulphur fertilizers

A field fallow soil monitoring method was used to evaluate the time of appearance of inorganic sulphate-S from two types of fertilizer S, elemental and sulphate, under the humid weather conditions of coastal British Columbia. In addition to both these types being applied as commercially produced granules, elemental S was applied as a powder. All three S-fertilizers were surface applied, but not incorporated as would likely occur when applied to forages. Soil analyses on a control (no S added) showed that there was limited evidence of leaching of sulphate beyond 30 cm. This meant sampling the soil to 30 cm depth was sufficient to examine the effect of a single spring application of the fertilizer over a full year. Differences in appearance of sulphate in the soil from the three fertilizer sources were distinguished by soil analyses, but the relatively large variability of the measurements limited the precision of time differentiation. The recovery calculations showed that inorganic sulphate from the fertilizers changed to another form (assumed to be organic S) as the season progressed. Maximum recovery of the granulated gypsum fertilizer (62–80%) was greater than for powdered elemental S (36–65%), which was slightly greater than for the SulFer 95 granulated elemental S fertilizer (33–48%).Key words: Elemental S, granulated S, gypsum, S fertilizers, extractable inorganic sulphate

Closure between measured and modelled particle hygroscopic growth during TORCH2 implies ammonium nitrate artefact in the HTDMA measurements

Measurements of aerosol properties were made in aged polluted and clean background air masses encountered at the North Norfolk (UK) coastline during the second field campaign of the Tropospheric ORganic CHemistry project (TORCH2) in May 2004. Hygroscopic growth factor (GF) measurements were performed at 90% relative humidity (RH) for D0=27–217 nm particles using a Hygroscopicity Tandem Differential Mobility Analyser (HTDMA), while the aerosol composition was simultaneously measured with an Aerodyne aerosol mass spectrometer (Q-AMS). During the clean background events the aerosol was characterised by little size dependence of properties with generally large GFs and inorganic sulphate being the dominant compound. In aged polluted air masses the particles were dominated by inorganic sulphate and nitrate at larger sizes, whereas organics were the largest fraction in smaller particles, thus explaining the trend of smaller GFs at smaller sizes. Organics do contribute to the hygroscopic growth, particularly at small sizes, but generally the dominant contribution to growth at 90% RH comes from inorganic salts. The ZSR mixing rule was used to predict GFs based on the chemical composition, theoretical GFs of pure inorganic salts and a "bulk" GF of ~1.20 for the organics. Good quantitative closure with HTDMA measurements as a function of both particle size and time was achieved in the absence of nitrate. However, GFs were clearly overpredicted at times when a significant fraction of nitrate was present. After careful considerations we attribute the overprediction to substantial evaporation losses of ammonium nitrate in the HTDMA instrument. If true, this implies that the ZSR predictions based on composition might be more representative of the actual "bulk" behaviour of undisturbed ambient particles than the HTDMA measurements. The simplified model approach using the ZSR rule and a constant organic growth factor made high size and time resolution possible, which has proven to be essential for a valid closure study. The ZSR mixing rule appears to be sufficiently accurate, as the GF predictions are more sensitive to the exact GFs of the inorganic compounds than to the growth factor of the moderately hygroscopic organics. Therefore a more detailed analysis and modelling of the organic fraction at the expense of time and size resolution is not worth the effort for an aged aerosol and discrepancies in either direction might even be cancelled out by averaging.

Binding of inorganic sulphate and phosphate in humid-climate soils measured using column leaching, equilibration and extraction methods

The ability of soil samples to bind applications of inorganic sulphate and phosphate was examined in the laboratory using column leaching, solution equilibration and extraction methods. Eleven soil samples from the Fraser Valley of British Columbia with a range of soil characteristics and management histories were examined. Column leaching trials showed that sulphate was bound to soils, but not as strongly as phosphate. There was no evidence of significant sulphate binding during the equilibration trials but there was substantial native sulphate bound by the soils as shown by extraction of significant sulphate concentrations by bicarbonate extraction following equilibration. This shows that sulphate is not bound according to the traditional theory of adsorption, but other undefined mechanisms are involved. Both column leaching and equilibration results showed that the samples studied varied considerably in their native phosphate retention attributes, with some samples releasing no phosphate and others releasing considerable phosphate into the water treatments. Equilibration trials showed that some of the soils bound large quantities of phosphate resulting in no phosphate in the soil solution whereas others bound much less resulting in significant phosphate concentrations in the soil solution. Phosphate binding followed the Freundlich equation in eight of the samples, the Tempkin equation in one sample and a direct linear relationship in two samples. The Langmuir equation fitted most of the samples that had followed Freundlich equation reasonably well, but did not fit the other samples. This showed that determination of the maximum amount of phosphate that can be bound by the sample (i.e., P saturation) using the Langmuir equation cannot be used for all humid-climate soils of British Columbia. Two alternate direct measurements are proposed to determine the potential risk of phosphate in soils to contaminate water: amount of phosphate released during equilibration with water (native unbound phosphate) and amount of phosphate bound during equilibration with a low (approximately 25 mg P kg-1) phosphate solution (potential for the soil to bind applied P). These results show that sulphate and phosphate binding mechanisms by coastal British Columbia soils are not well understood. The nature of the binding mechanisms needs to be determined to develop and interpret soil analyses for agronomic and environmental purposes. Key words: Sulphate binding, phosphate binding, P saturation, soil solution P