Iron Uptake by Symbiosomes from Soybean Root Nodules.

To identify possible iron sources for bacteroids in planta, soybean (Glycine max L. Merr.) symbiosomes (consisting of the bacteroid-containing peribacteroid space enclosed by the peribacteroid membrane [PBM]) and bacteroids were assayed for the ability to transport iron supplied as various ferric [Fe(III)]-chelates. Iron presented as a number of Fe(III)-chelates was transported at much higher rates across the PBM than across the bacteroid membranes, suggesting the presence of an iron storage pool in the peribacteroid space. Pulse-chase experiments confirmed the presence of such an iron storage pool. Because the PBM is derived from the plant plasma membrane, we reasoned that it may possess a ferric-chelate reductase activity similar to that present in plant plasma membrane. We detected ferric-chelate reductase activity associated with the PBM and suggest that reduction of Fe(III) to ferrous [Fe(II)] plays a role in the movement of iron into soybean symbiosomes

Lipid Disturbances in Adolescents Treated With Second-Generation Antipsychotics: Clinical Determinants of Plasma Lipid Worsening and New-Onset Hypercholesterolemia.

Lipid disturbances following treatment with second-generation antipsychotics (SGAs) represent a major health concern. A previous study determined that early changes of plasma lipid levels ≥ 5% during the first month of treatment with SGAs predicts further lipid worsening and development of dyslipidemia. This current study aimed to determine the proportion of adolescents with early lipid changes ≥ 5% and who develop dyslipidemia during SGA treatment. Data were obtained from a 1-year longitudinal study ongoing since 2007 including 53 adolescent psychiatric (ICD-10) patients (median age 16.5 years; interquartile range [IQR], 14.8-17.5 years) whose metabolic parameters were monitored prospectively during treatment. Plasma lipid levels (total, low-density lipoprotein, high-density lipoprotein [HDL-C], and non-high-density lipoprotein cholesterol and fasting triglycerides ) were measured at baseline and after 1, 3, and/or 12 months of SGA treatment. Half (n = 26; 49%) the adolescents had an early increase of total cholesterol levels by 5% or more during the first month of treatment, and one-third (n = 8/24; 33%) developed new-onset hypercholesterolemia during the first year of treatment. Hypercholesterolemia developed more frequently in female patients (P = .01) and in patients with an early increase of total cholesterol ≥ 5% (P = .02). Finally, patients whose HDL-C levels decreased by ≥ 5% during the first month of treatment had a larger HDL-C worsening after 3 months of treatment as compared with patients with early decrease of HDL-C by < 5% (P = .02). This study underlines the importance of prospectively monitoring metabolic parameters in adolescents after the introduction of SGAs

Partial complementation of Sinorhizobium meliloti bacA mutant phenotypes by the Mycobacterium tuberculosis BacA protein

The Sinorhizobium meliloti BacA ABC transporter protein plays an important role in its nodulating symbiosis with the legume alfalfa (Medicago sativa). The Mycobacterium tuberculosis BacA homolog was found to be important for the maintenance of chronic murine infections, yet its in vivo function is unknown. In the legume plant as well as in the mammalian host, bacteria encounter host antimicrobial peptides (AMPs). We found that the M. tuberculosis BacA protein was able to partially complement the symbiotic defect of an S. meliloti BacA-deficient mutant on alfalfa plants and to protect this mutant in vitro from the antimicrobial activity of a synthetic legume peptide, NCR247, and a recombinant human \u3b2-defensin 2 (HBD2). This finding was also confirmed using an M. tuberculosis insertion mutant. Furthermore, M. tuberculosis BacA-mediated protection of the legume symbiont S. meliloti against legume defensins as well as HBD2 is dependent on its attached ATPase domain. In addition, we show that M. tuberculosis BacA mediates peptide uptake of the truncated bovine AMP, Bac71-16. This process required a functional ATPase domain. We therefore suggest that M. tuberculosis BacA is important for the transport of peptides across the cytoplasmic membrane and is part of a complete ABC transporter. Hence, BacA-mediated protection against host AMPs might be important for the maintenance of latent infections

Regional circulation patterns of Mediterranean Outflow Water near the Iberian and African continental slopes

The Mediterranean Outflow Water (MOW) is a dense water mass originated in the Strait of Gibraltar. Downstream of the Gulf of Cádiz, the MOW forms a reservoir region west of the Iberian continental slopes at a buoyant depth of approximately 1000&thinsp;m. This region plays a key role as the main centre where the MOW is mixed and distributed into the North Atlantic. The seafloor in this area is characterized by the presence of a complex bathymetry with three abyssal plains separated by mountain chains. Although the topographic features do not reach the surface, they influence ocean flows at intermediate and deep ocean layers, conditioning the distribution and circulation of MOW. The Copernicus Marine Environmental Monitoring Service (CMEMS) Iberian–Biscay–Ireland (IBI) ocean reanalysis is used to provide a detailed view of the circulation and mixing processes of MOW near the Iberian and African continental slopes. This work emphasizes the relevance of the complex bathymetric features defining the circulation processes of MOW in this region. The high resolution of the IBI reanalysis allows us to make a description of the mesoscale features forced by the topography. The temperature, salinity, velocity, transport, and vorticity fields are analysed to understand the circulation patterns of MOW. The high-resolution circulation patterns reveal that Horseshoe Basin and the continental slope near Cape Ghir (a.k.a. Cap Rhir or Cabo de Aguer) are key areas controlling the mixing processes of MOW with the surrounding water masses, mainly North Atlantic Central Water (NACW) and Antarctic Intermediate Water (AAIW). The water mass variability is also analysed by means of composite analysis. Results indicate the existence of a variability in the MOW tongue which retracts and expands westwards in opposition to the movement of the underlying North Atlantic Deep Water.</p

Protection of Sinorhizobium against Host Cysteine-Rich Antimicrobial Peptides Is Critical for Symbiosis

A bacterial membrane protein, BacA, protects Sinorhizobium meliloti against the antimicrobial activity of host peptides, enabling the peptides to induce bacterial persistence rather than bacterial death

Copernicus Marine Service Ocean State Report

This is the final version. Available from Taylor & Francis via the DOI in this record

Copernicus Marine Service ocean state report, issue 4

This is the final version. Available from Taylor & Francis via the DOI in this record. FCT/MCTE

Characterization of adenosine A1 receptor in a cell line (28A) derived from the rabbit collecting tubule

We have previously reported that in several renal cell types, adenosine receptor agonists inhibit adenylyl cyclase and activate phospholipase C via a pertussis toxin-sensitive G protein. In the present study, in 28A cells, both uf these adenosine receptor-mediated responses were inhibited by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). a highly selective A1 adenosine receptor antagonist. The binding characteristics of the adenosine A 1 receptor in the 28A renal cell line were studied using the radiolabeled antagonist f:1H]DPCPX to determine whether two separate binding sites could account for these responses. Saturation binding of [: 1H]DPCPX to 28A cell membranes revealed a single class of A1 binding sites with an apparent Kd value of 1.4 nM and maximal binding capacity of 64 fmol/mg protein. Competition experiments with a variety of adenosine agonists gave biphasic displacement curves with a pharmacological profile characteristic of A1 receptors. Comparison of [: 1H]DPCPX competition binding data from 28A cell membranes with rabbit brain membranes, a tissue with well-characterized A1 receptors, reveals that the A 1 receptor population in 28A cells has similar agonist binding affinities to the receptor population in brain but has a considerably lower density. Addition of guanosine ;)' -triphosphate ( 100 ,uM) to 28A cell membranes caused the competition curves to shift from biphasic to monophasic. indicating that the A1 receptors exist in two interconvertible affinity states because of their coupling to G proteins. In the absence of evidence for subpopulations of the A1 receptor, it appears that in 28A cells. A single A1 receptor population. As defined by ligand binding characteristics, couples via one or more pertussis toxin-sensitive guanine nucleotide binding proteins to two different biological signaling mechanisms

Determination of low level of actinium 227 in seawater and freshwater by isotope dilution and mass spectrometry

By diffusing from the sediments into the ocean, 227Ac (half-life = 21.7 y) is a powerful tracer of vertical mixing in the deep ocean on decadal time scales. However, its use is limited by its very low concentration resulting in large volumes (hundreds of L) of water required for its analysis. We have developed a new method of 227Ac analysis by isotope dilution and MC-ICPMS that significantly improves the measurement accuracy and reduces the sample size (10−30L). After spiking water samples with 225Ac milked from a 229Th solution, actinium isotopes are preconcentrated by manganese co-precipitation, purified by chromatographic methods and then measured by MC-ICPMS. The performance of the analytical method (accuracy, precision) was estimated with a homemade actinium standard solution. An internal quality control was carried out to validate the method by repeated measurements of 2 L of surface seawater doped with 227Ac (1000 ag/kg) and duplicates of the Vienne river water (6.1 ± 1.7 ag/kg and 4.1 ± 1.3 ag/kg). 231Pa was also co-precipitated, purified during the chromatography and analysed by MC-ICPMS. The combined measurement of 227Ac and 231Pa from the same sample allows discriminating 227Ac supported by 231Pa decay from the 227Ac released by remobilization from the sediments. The 227Ac concentrations measured on the first seawater samples of 29 L from the South China Sea water range from below the detection limit in surface water (~ 0.5 ag/kg for 30 L) to 3.4 ± 0.5 ag/kg at 2760 m depth (uncertainties are given in 2σn). The 227Ac measured in the deep South China Sea waters entering through the Luzon strait are consistent with previous data obtained in the same water mass in the Pacific Ocean (PDW). Seawater from the southernmost station of Bonus GoodHope, in the Weddell Gyre, were also analysed, with 227Ac concentration ranging from 4.2 ± 0.4 ag/kg to 10.9 ± 1.0 ag/kg in good agreement with previous measurement in the Weddell Gyre by Geibert et al. (2002, 2008)