Long-term effectiveness of vivianite in reducing iron chlorosis in olive trees

Iron (Fe) chlorosis is common in olive (Olea europaea L.) trees growing on highly calcareous soils in Southern Spain, where generally causes reduction in yield, size and commercial value of the olives. The objective of this research was to study the effectiveness of synthetic vivianite (Fe₃(PO₄)₂H₂O) to reduce Fe chlorosis in olive. Experiments were established in three orchards with cultivars `Hojiblanco', `Manzanillo', and `Picual'. The design was a randomised block design with two or three treatments (control with no Fe fertiliser and vivianite at one or two rates). A vivianite suspension (0.05 kg dm<sup>–3</sup> water) was injected into the soil at 10–20 points around the tree at the depth of maximum root density (25–35 cm). The rates (and times of application) were 0.5 and 1 kg tree<sup>–1</sup> for `Hojiblanco' (March 1997), 1 kg tree^–1 for `Manzanillo' (March 1998), and 2 kg tree<sup>–1</sup> for `Picual' (March 1998). The leaf chlorophyll content index (CCI) was estimated on the youngest expanded leaves by means of a Minolta apparatus (SPAD units). The colour index of the olives was estimated by visual comparison with a scale ranging from 1 (pale yellow) to 8 (normal green). For the period studied (July 1997–November 1999), the CCI of fertilised trees was, in general, significantly higher than that of control trees, and so was the case with the olive colour index. Olive yield, measured in the experimental fields with `Hojiblanco' (in 1999) and `Manzanillo' (in 1998 and 1999), was higher for the fertilised than for the control trees but differences were only significant in 1999. These results suggest that vivianite is effective to reduce Fe chlorosis for more than two seasons. Such effectiveness is probably due to the poorly crystalline Fe(III) oxides (which are good sources of Fe to plants) that result from the slow oxidation and incongruent dissolution of vivianite.     

Cytokine profile of autologous conditioned serum for treatment of osteoarthritis, <Emphasis Type="Italic">in vitro</Emphasis>effects on cartilage metabolism and intra-articular levels after injection

Introduction  

Intraarticular administration of autologous conditioned serum (ACS) recently demonstrated some clinical effectiveness in treatment of osteoarthritis (OA). The current study aims to evaluate the in vitro effects of ACS on cartilage proteoglycan (PG) metabolism, its composition and the effects on synovial fluid (SF) cytokine levels following intraarticular ACS administration.     

Selected anthropometric variables and aerobic fitness as predictors of cardiovascular disease risk in children

The aim of this study was to assess the suitability of body mass index, waist circumference, waist-to-height ratio and aerobic fitness as predictors of cardiovascular risk factor clustering in children. A cross-sectional study was conducted with 290 school boys and girls from 6 to 10 years old, randomly selected. Blood was collected after a 12-hour fasting period. Blood pressure, waist circumference (WC), height and weight were evaluated according to international standards. Aerobic fitness (AF) was assessed by the 20-metre shuttle-run test. Clustering was considered when three of these factors were present: high systolic or diastolic blood pressure, high low-density lipoprotein (LDL) cholesterol, high triglycerides, high plasma glucose, high insulin concentrations and low high-density lipoprotein (HDL) cholesterol. A ROC curve identified the cut-off points of body mass index (BMI), WC, waist-to-height ratio (WHtR) and AF as predictors of risk factor clustering. BMI, WC and WHR resulted in significant areas under the ROC curves, which was not observed for AF. The anthropometric variables were good predictors of cardiovascular risk factor clustering in both sexes, whereas aerobic fitness should not be used to identify cardiovascular risk factor clustering in these children.     

Treatment with a sphingosine analog after the inception of house dust mite-induced airway inflammation alleviates key features of experimental asthma

Background

In vivo phosphorylation of sphingosine analogs with their ensuing binding and activation of their cell-surface sphingosine-1-phosphate receptors is regarded as the main immunomodulatory mechanism of this new class of drugs. Prophylactic treatment with sphingosine analogs interferes with experimental asthma by impeding the migration of dendritic cells to draining lymph nodes. However, whether these drugs can also alleviate allergic airway inflammation after its onset remains to be determined. Herein, we investigated to which extent and by which mechanisms the sphingosine analog AAL-R interferes with key features of asthma in a murine model during ongoing allergic inflammation induced by Dermatophagoides pteronyssinus.

Methods

BALB/c mice were exposed to either D. pteronyssinus or saline, intranasally, once-daily for 10 consecutive days. Mice were treated intratracheally with either AAL-R, its pre-phosphorylated form AFD-R, or the vehicle before every allergen challenge over the last four days, i.e. after the onset of allergic airway inflammation. On day 11, airway responsiveness to methacholine was measured; inflammatory cells and cytokines were quantified in the airways; and the numbers and/or viability of T cells, B cells and dendritic cells were assessed in the lungs and draining lymph nodes.

Results

AAL-R decreased airway hyperresponsiveness induced by D. pteronyssinus by nearly 70%. This was associated with a strong reduction of IL-5 and IL-13 levels in the airways and with a decreased eosinophilic response. Notably, the lung CD4⁺ T cells were almost entirely eliminated by AAL-R, which concurred with enhanced apoptosis/necrosis in that cell population. This inhibition occurred in the absence of dendritic cell number modulation in draining lymph nodes. On the other hand, the pre-phosphorylated form AFD-R, which preferentially acts on cell-surface sphingosine-1-phosphate receptors, was relatively impotent at enhancing cell death, which led to a less efficient control of T cell and eosinophil responses in the lungs.

Conclusion

Airway delivery of the non-phosphorylated sphingosine analog, but not its pre-phosphorylated counterpart, is highly efficient at controlling the local T cell response after the onset of allergic airway inflammation. The mechanism appears to involve local induction of lymphocyte apoptosis/necrosis, while mildly affecting dendritic cell and T cell accumulation in draining lymph nodes.     

The seventh transmembrane domains of the delta and kappa opioid receptors have different accessibility patterns and interhelical interactions

We applied the substituted cysteine accessibility method (SCAM) to map the residues of the transmembrane helices (TMs) 7 of delta and kappa opioid receptors (deltaOR and kappaOR) that are on the water-accessible surface of the binding-site crevices. A total of 25 consecutive residues (except C7.38) in the TMs 7 were mutated to Cys, one at a time, and each mutant was expressed in HEK 293 cells. Most mutants displayed similar binding affinity for [(3)H]diprenorphine, an antagonist, as the wild types. Pretreatment with (2-aminoethyl)methanethiosulfonate (MTSEA) inhibited [(3)H]diprenorphine binding to eight deltaOR and eight kappaOR mutants. All mutants except deltaOR L7.52(317)C were protected by naloxone from the MTSEA effect, indicating that the side chains of V7.31(296), A7.34(299), I7.39(304), L7.41(306), G7.42(307), P7.50(315), and Y7.53(318) of deltaOR and S7.34(311), F7.37(314), I7.39(316), A7.40(317), L7.41(318), G7.42(319), Y7.43(320), and N7.49(326) of kappaOR are on the water-accessible surface of the binding pockets. Combining the SCAM data with rhodopsin-based molecular models of the receptors led to the following conclusions. (i) The residues of the extracellular portion of TM7 predicted to face TM1 are sensitive to MTSEA in kappaOR but are not in deltaOR. Thus, TM1 may be closer to TM7 in deltaOR than in kappaOR. (ii) MTSEA-sensitive mutants start at position 7.31(296) in deltaOR and at 7.34(311) in kappaOR, suggesting that TM7 in deltaOR may have an additional helical turn (from 7.30 to 7.33). (iii) There is a conserved hydrogen-bond network linking D2.50 of the NLxxxD motif in TM2 with W6.48 of the CWxP motif in TM6. (iv) The NPxxY motif in TM7 interacts with TM2, TM6, and helix 8 to maintain receptors in inactive states. To the best of our knowledge, this represents the first such comparison of the structures of two highly homologous GPCRs.