Nature-inspired soluble iron-rich humic compounds: new look at the structure and properties

Purpose

Humic substances (HS) being natural polyelectrolyte macromolecules with complex and disordered molecular structures are a key component of the terrestrial ecosystem. They have remarkable influence on environmental behavior of iron, the essential nutrient for plants. They might be considered as environmental friendly iron deficiency correctors free of synthetic iron (III) chelates disadvantages. The main goal of this study was to obtain water-soluble iron-rich humic compounds (IRHCs) and to evaluate their efficiency as chlorosis correctors.

Materials and methods

A facile preparation technique of IRHCs based on low-cost and available parent material was developed. The iron-containing precursor (ferrous sulfate) was added dropwisely into alkaline potassium humate solution under vigorous stirring and pH-control. A detailed characterization both of organic and inorganic parts of the compounds was provided, the iron species identification was carried out jointly by EXAFS and Mössbauer spectroscopy. Bioassay experiments were performed using cucumber Cucumis sativus L. as target plants. Plants were grown in modified Hoagland nutrient solution, prepared on deionized water and containing iron in the form of IRHCs. Total iron content in dry plants measured by spectrophotometry after oxidative digestion and the chlorophyll a content determined after acetone extraction from fresh plant were used as parameters illustrating plants functional status under iron deficiency condition.

Results and discussion

The high solubility (up to130 g/l) and iron content (about 11 wt%) of the IRHCs obtained allow considering them to be perspective for practical applications. A set of analytical methods has shown that the main iron species in IRHCs are finely dispersed iron (III) oxide and hydroxide nanoparticles. An application of the precursor solution acidification allows to obtain compounds containing a significant part of total iron (up to 30 %) in the form of partly disordered iron (II–III) hydroxysulphate green rust GR(SO₄ ^2?). Bioavailability of iron from IRHCs was demonstrated using bioassay in cucumber plants grown up on hydroponics under iron deficiency conditions.

Conclusions

The application of iron oxides chemistry for humic substance containing solution was proved to be an effective approach to synthesis of IRHCs. Using bioassay on cucumber plants C. sativus L. under iron deficiency conditions, the efficiency of compounds obtained as chlorosis correctors was demonstrated. Application of water-soluble IRHCs led to significant increase of chlorophyll a content (up to 415 % of the blank) and iron content in plants (up to 364 % of the blank) grown up on hydroponics.     

Calcium carbonate accumulations in Technosols of Moscow city

Journal of Soils and Sediments - Complex phenomena of the precipitation and accumulation of calcium carbonate in urban soils and sediments have been studied. They are linked to the interactions...     

Larger bioavailability of soil phosphorus for irrigated rice compared with rainfed rice in Madagascar: results from a soil and plant survey

Irrigated rice is less prone generally to phosphorus (P) deficiency than rainfed rice because redox reactions release P upon soil flooding. It is not known whether that is also true in highly weathered soils of Madagascar where the combination of high soil Fe and low P input may impede significant release of P. Soils and flag leaf samples were collected in 2010 in 38 irrigated rice and 46 rainfed rice fields belonging to private farmers. A critical flag leaf P content was derived from a P‐dosed pot trial study with three soils, and the results suggested 2.4 g P/kg as the critical value. Average flag leaf P was significantly larger in irrigated than in rainfed rice (2.2 compared with 1.7 g P/kg), and flag leaf P was below the critical value in 76% of irrigated rice fields while this fraction was 100% in rainfed rice. Nitrogen and K deficiencies were less prevalent. Flag leaf P increased with increasing soil pH and soil pH explained partially differences in leaf P between irrigated and rainfed rice. Flag leaf P was unrelated to soil organic matter, but increased with oxalate‐extractable soil P (P_o). Multiple regression analysis revealed greater leaf P at equal soil P_o and equal pH in irrigated compared with rainfed rice. Grain yield estimates (1‐m² squares) increased with flag leaf P but not with leaf N and K. In a regression model, about 42 % of the yield variance was explained with soil P_o and a rice‐growing system. The survey suggests that P is the main limiting nutrient for rice, and that soil P bioavailability is larger for irrigated than for rainfed rice in weathered soils of Madagascar.     

Genetic Relationships and Variation among Biotypes of Dallisgrass (Paspalum dilatatum Poir.) and Related Species Using Random Amplified Polymorphic DNA Markers

The genus Paspalum L. consists of more than 400 species. Around twenty-five informal groups of species are recognized in Paspalum and the Dilatata group is of special interest because its members are excellent potential forage grasses. Seventy-five germplasm accessions, representing 15 taxa, were analyzed using randomly amplified polymorphic DNA (RAPD). Polymorphisms were observed with twenty-two primers in the Dilatata group and 16 of those were analyzed. Four hundred and four different RAPD fragments were generated, resulting in an average of 25.2 bands per primer. Among the 404 markers analyzed, 48 (11.88%) were exclusive for the P. dilatatum Poir. biotypes, 31 (7.67%) were exclusive to taxa belonging to other groups included in this study, 28 markers (6.93%) were diagnosed for other species of the Dilatata group and 16 (3.96%), for natural hybrids. Extensive RAPD variation was found among the species studied. Inter- and intra-taxonomic polymorphisms were detected. A dendrogram based on the RAPD data shows some clusters corresponding to the same taxa. However, the biotypes of P. dilatatum do not form a cluster. The present work confirms that the RAPD technique can be used to determine genetic relationships between the taxa belonging to the Dilatata group.     

Epidural anesthesia with bupivacaine, bupivacaine and fentanyl, or bupivacaine and sufentanil during intravenous administration of propofol for ovariohysterectomy in dogs

OBJECTIVE: To compare cardiovascular and systemic effects and analgesia during the postoperative period of epidural anesthesia performed with bupivacaine alone or with fentanyl or sufentanil in bitches maintained at a light plane of anesthesia with continuous infusion of propofol. STUDY DESIGN: Prospective randomized masked clinical trial. ANIMALS: 30 female dogs of various breeds. PROCEDURES: Dogs were allocated into 3 groups of 10 each. One group received fentanyl (2 microg/kg [0.91 microg/lb]) and bupivacaine (1 mg/kg [0.45 mg/lb]), 1 group received sufentanil (1 microg/kg) and bupivacaine (1 mg/kg), and 1 group received bupivacaine (1 mg/kg). All dogs received acepromazine (0.1 mg/kg [0.045 mg/lb]) and continuous infusion of propofol for sedation. The agents were administered into the lumbosacral space and diluted in saline (0.9% NaCl) solution to a total volume of 0.36 mL/kg (0.164 mL/lb). Cardiac and respiratory rates, arterial blood pressures, pH, and blood gases were evaluated. Analgesia, sedation level, serum cortisol concentrations, and plasma catecholamine concentrations were measured regularly for 6 hours. RESULTS: No important changes in cardiovascular, respiratory, or sedation variables were observed. Degree of analgesia in the postoperative period was higher in the sufentanil group, although use of fentanyl and bupivacaine also resulted in a sufficient level of analgesia. CONCLUSIONS AND CLINICAL RELEVANCE: Use of the 3 anesthetic techniques permitted ovariohysterectomy with sufficient analgesia and acceptable neuroendocrine modulation of pain with minimal adverse effects.     

Sternal recumbency or suspension by the hind legs immediately after delivery improves respiratory and metabolic adaptation to extra uterine life in newborn calves delivered by caesarean section

The aim of this study was to evaluate the effect of body positioning immediately after delivery on respiratory and metabolic adaptation to extra-uterine life in newborn calves. One hundred and one Belgian White and Blue calves were delivered at term by an elective caesarean section and were assigned into three categories according to the body position imposed immediately after umbilical cord rupture: 71 calves were placed in lateral recumbency; 16 calves were placed in sternal recumbency and 14 calves were suspended by the hind legs for less than 90 seconds (75 +/- 5 s). Following this initial body position, the calves were allowed to move without restraint. They were examined at birth, 5, 15, 30, 45 and 60 minutes, and 2, 3, 6, 12 and 24 hours after birth by the following measurements: physical examination, heart rate, arterial blood gas analysis, pulmonary function tests using the esophageal balloon catheter technique, arterial and venous blood acid-base balance analysis, rectal temperature, jugular venous blood sampling for the determination of blood glucose, plasma lactate and serum cortisol concentrations, haematologic variables and passive immune transfer variables. Body positioning immediately after delivery clearly influenced respiratory and metabolic adaptation to extra-uterine life in term calves delivered by an elective caesarean section. Systematic sternal recumbency and suspension by the hind legs for less than 90 seconds immediately after umbilical cord rupture had a positive functional impact on postnatal pulmonary mechanics and gas exchange and on postnatal correction of mixed acidosis present at birth, contributing in turn to an enhanced passive immune transfer. These two body positions should be encouraged to improve adaptation at birth in healthy term calves delivered by an elective caesarean section. Evaluation of possible side-effects is required before application in severely asphyxiated calves.     

Cell surface expression of a chimeric protein containing mouse immunoglobulin G1 Fc domain and its immunological property

Recently we reported that a chimeric molecule containing mouse transferrin receptor and immunoglobulin G1 (IgG1) Fc, mTR-Fc, induced higher immune responses and can be used as a vaccine adjuvant. In this study, the immunological property of the molecule was investigated. Although, the mTR-Fc did not activate complement classical pathway, it was recognized by activated macrophage as like intact IgG Fc, which is recognized by macrophage via Fcgamma receptor. In addition, we found that splenocyte simultaneously exposed to lipopolysaccaride (LPS) and mTR-Fc produced higher amount of interleukin-10, comparing to that exposed to only LPS. These results suggest that the mTR-Fc molecules conserved the IgG Fc property to biasing immune responses via modulation of cytokine production by antigen presenting cell.     

Pharmacokinetic and pharmacodynamic modelling of intravenous,intramuscular and subcutaneous buprenorphine in conscious cats

ObjectiveTo describe simultaneous pharmacokinetics (PK) and thermal antinociception after intravenous (IV), intramuscular (IM) and subcutaneous (SC) buprenorphine in cats.Study designRandomized, prospective, blinded, three period crossover experiment.AnimalsSix healthy adult cats weighing 4.1 ± 0.5 kg.MethodsBuprenorphine (0.02 mg kg^?1) was administered IV, IM or SC. Thermal threshold (TT) testing and blood collection were conducted simultaneously at baseline and at predetermined time points up to 24 hours after administration. Buprenorphine plasma concentrations were determined by liquid chromatography tandem mass spectrometry. TT was analyzed using anova (p < 0.05). A pharmacokinetic-pharmacodynamic (PK-PD) model of the IV data was described using a model combining biophase equilibration and receptor association-dissociation kinetics.ResultsTT increased above baseline from 15 to 480 minutes and at 30 and 60 minutes after IV and IM administration, respectively (p < 0.05). Maximum increase in TT (mean ± SD) was 9.3 ± 4.9 °C at 60 minutes (IV), 4.6 ± 2.8 °C at 45 minutes (IM) and 1.9 ± 1.9 °C at 60 minutes (SC). TT was significantly higher at 15, 60, 120 and 180 minutes, and at 15, 30, 45, 60 and 120 minutes after IV administration compared to IM and SC, respectively. IV and IM buprenorphine concentration-time data decreased curvilinearly. SC PK could not be modeled due to erratic absorption and disposition. IV buprenorphine disposition was similar to published data. The PK-PD model showed an onset delay mainly attributable to slow biophase equilibration (t_1/2k_e0 = 47.4 minutes) and receptor binding (k_on = 0.011 mL ng^?1 minute^?1). Persistence of thermal antinociception was due to slow receptor dissociation (t_1/2k_off = 18.2 minutes).Conclusions and clinical relevanceIV and IM data followed classical disposition and elimination in most cats. Plasma concentrations after IV administration were associated with antinociceptive effect in a PK-PD model including negative hysteresis. At the doses administered, the IV route should be preferred over the IM and SC routes when buprenorphine is administered to cats.     

Effects of n-3 Polyunsaturated Fatty Acids (ω-3) Supplementation on Some Cardiovascular Risk Factors with a Ketogenic Mediterranean Diet

Background: the ketogenic diet (KD) has become a widely used nutritional approach for weight loss. Some of the KD’s positive effects on metabolism and cardiovascular risk factors are similar to those seen after n-3 polyunsaturated fatty acids (ω-3) supplementation. We hypothesized that a ketogenic Mediterranean diet with phytoextracts combined with ω-3 supplementation may have increased positive effects on cardiovascular risk factors and inflammation. Methods: We analyzed 34 male overweight subjects; aged between 25 and 65 years who were overall healthy apart from overweight. The subjects followed a ketogenic diet protocol for four weeks; with (KDO3) or without (KD) ω-3 supplementation. Results: All subjects experienced a significant loss of body weight and body fat and there was no significant differences between treatment (body weight: KD—4.7 kg, KDO3—4.03 kg, body fat KD—5.41 kg, KDO3—5.86 kg). There were also significant decreases in total cholesterol, LDL-c, and glucose levels. Triglycerides and insulin levels decreased more in KDO3 vs. KD subjects, with a significant difference. All the investigated inflammatory cytokines (IL-1β, IL-6, TNF-α) decreased significantly in KDO3 subjects whilst only TNF-α showed a significant decrease in KD subjects over the 12 month study period. No significant changes were observed in anti-inflammatory cytokines (IL-10 and IL-1Ra), creatinine, urea and uric acid. Adiponectin increased significantly only in the KDO3 group. Conclusions: ω-3 supplementation improved the positive effects of a ketogenic Mediterranean diet with phytoextracts on some cardiovascular/metabolic risk factors and inflammatory state.