Accumulation of technetium by cyanobacteria

Accumulation of pertechnetate ions (⁹⁹TcO₄ ^–) by the cyanobacterial speciesSynechocystis PCC 6803,Synechococcus PCC 6301,Plectonema boryanum,Anabaena variabilis and a redOscillatoria sp. consisted solely of a single rapid energy-independent phase (biosorption); no energy-dependent uptake was detected. Biosorption of TcO₄ ^– was concentration-dependent and could be described by a Freundlich adsorption isotherm for each cyanobacterial species examined. Decreasing pH increased the accumulation of TcO₄ ^– by all the species as did an increase in external NaCl concentration. Accumulation of TcO₄ ^– was also increased inA. variabilis, P. boryanum and the redOscillatoria by an increased external osmotic potential. Concentrations of cations affected TcO₄ ^– accumulation; K⁺ increased accumulation in all the species, Mg²⁺, Ca²⁺, Sr²⁺ and Cs⁺ increased accumulation inSynechococcus PCC 6301 and Ca²⁺ increased accumulation by the redOscillatoria. Some anions decreased TcO₄ ^– accumulation; CO₃ ^2– inA. variabilis and the redOscillatoria, SO₄ ^2– inSynechocystis PCC 6803, and HCO₃ ^– inP. boryanum. The majority of TcO₄ ^– accumulated by all the cyanobacteria was easily desorbed, with no difference in the amounts desorbed between desorption agents of different pH or cation concentration.(*author for correspondence)     

Effect of salinity and pH on cobalt biosorption by the estuarine microalgaChlorella saliva

Summary Accumulation of cobalt (⁶⁰Co) by the estuarine microalgaChlorella salina has been characterized. At cobalt concentrations ranging over 3.125–100 M, a significant amount of cobalt was bound within 1 min. This was metabolism-independent and unaffected by incubation in light or dark conditions. This initial rapid phase of biosorption was followed by a slower phase of uptake which was apparently active and inhibited by incubation in the dark, or by the uncoupler dinitrophenol and the respiratory and photosynthetic inhibitor potassium cyanide in the light. For cells suspended in 10 mM Taps pH 8, cobalt biosorption followed a Freundlich adsorption isotherm. However, in the presence of 0.5 M NaCl, biosorption deviated from the Freundlich model because of competition by Na⁺. Cobalt biosorption was decreased by increasing concentrations of Na⁺, decreasing pH and the presence of Cs⁺, Li⁺, Rb⁺, Zn²⁺. Mn²⁺ and Sr²⁺ (added as chlorides). This was a result of competition between Co²⁺ and the other cations, including H⁺, for available binding sites on the cell wall and was confirmed by increased desorption of cobalt by solutions of low pH or high salinity. Increasing cell density resulted in increased removal of cobalt from solution but decreased the specific amount of cobalt taken up by the cells.     

Uptake of technetium by freshwater green microalgae

Summary Accumulation of [⁹⁹Tc]pertechnetate ions (⁹⁹TcO₄ ^–) by the freshwater microalgae Chlorella emersonii, Chlamydomonas reinhardtii and Scenedesmus obliquus has been characterized. In all three species, accumulation consisted of a single rapid energy-independent phase (biosorption), and no energy-dependent accumulation was observed. Biosorption of ⁹⁹TcO _inf4 ^sup– by all three species was concentration dependent, followed a Freundlich adsorption isotherm, and was dependent on pH with increased accumulation by cells with decreasing external pH. Elevated external NaCl concentrations also caused increased accumulation of ⁹⁹TcO _inf4 ^sup– by the cells, as did increased external osmotic potential. Concentrations of K⁺, Mg²⁺ and Ca²⁺ increased accumulation of ⁹⁹TcO _inf4 ^sup– , but concentrations of HCO _inf3 ^sup– , SO _inf4 ^sup2– and CO _inf3 ^sup2– decreased ⁹⁹TcO _inf4 ^sup– accumulation by the cells. Most of the ⁹⁹TcO _inf4 ^sup– accumulated by all three species was easily desorbed by 10 mm buffers at various pH values, 0.5 m NaCl, 10 mm Na₂CO₃ or 10 mm Na₂SO₄. No differences in the amount of desorption were observed between the various desorption agents used. Correspondence to: G. M. Gadd     

Lung tissue extracellular matrix-derived hydrogels protect against radiation-induced lung injury by suppressing epithelial–mesenchymal transition

This study aimed to examine whether lung tissue extracellular matrix (ECM) hydrogels have protective effects on radiation-induced lung injury (RILI). The cytocompatibility and histocompatibility were tested for the obtained ECM-derived hydrogel. Sprague–Dawley rats were randomly divided into three groups (n = 18): control group (control); rats receiving irradiation and intratracheal injection of normal saline (IR + NS); and rats receiving irradiation and intratracheal injection of lung ECM-derived hydrogel (IR + ECM). The wet/dry weight ratio was used to evaluate the congestion and edema of the lungs. Histopathological analysis of lung tissues was performed using hemotoxylin and eosin staining and Masson's trichrome staining. Immunohistochemical staining and western blot analyses were carried out to determine the expression of epithelial–mesenchymal transition (EMT)-related proteins in lung tissues (E-cadherin, α-smooth muscle actin [α-SMA], and vimentin). In addition, tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1) and interleukin-6 (IL-6), hydroxyproline, malondialdehyde (MDA), and superoxide dismutase (SOD) levels were also evaluated. The ECM-derived hydrogels had good cytocompatibility and histocompatibility. ECM-derived hydrogel treatment improved lung histopathology injury and pulmonary edema. Higher expression of E-cadherin and lower expression of vimentin and α-SMA were found in the IR + ECM group compared with those in the IR + NS group. Hydroxyproline levels were reduced by ECM-derived hydrogel treatment compared with those in the IR + NS group. Obvious increases of TNF-α, IL-6, and TGF-β1 were identified following irradiation. Marked reductions in MDA content and increases in SOD were induced by ECM-derived hydrogel treatment in rats after radiation. ECM-derived hydrogels were shown to protect against RILI, potentially by reducing EMT, inflammation, and oxidative damage.     

Increased insulin-stimulated Akt pSer473 and cytosolic SHP2 protein abundance in human skeletal muscle following acute exercise and short-term training.

The purpose of the present study was to determine in human skeletal muscle whether a single exercise bout and 7 days of consecutive endurance (cycling) training 1) increased insulin-stimulated Akt pSer(473) and 2) altered the abundance of the protein tyrosine phosphatases (PTPases), PTP1B and SHP2. In healthy, untrained men (n = 8; 24 +/- 1 yr), glucose infusion rate during a hyperinsulinemic euglycemic clamp, when compared with untrained values, was not improved 24 h following a single 60-min bout of endurance cycling but was significantly increased ( approximately 30%; P < 0.05) 24 h following completion of 7 days of exercise training. Insulin-stimulated Akt pSer(473) was approximately 50% higher (P < 0.05) 24 h following the acute bout of exercise, with this effect remaining after 7 days of training (P < 0.05). Insulin-stimulated insulin receptor and insulin receptor substrate-1 tyrosine phosphorylation were not altered 24 h after acute exercise and short-term training. Insulin did not acutely regulate the localization of the PTPases, PTP1B or SHP2, although cytosolic protein abundance of SHP2 was increased (P < 0.05; main effect) 24 h following acute exercise and short-term training. In conclusion, insulin-sensitive Akt pSer(473) and cytosolic SHP2 protein abundance are higher after acute exercise and short-term training, and this effect appears largely due to the residual effects of the last bout of prior exercise. The significance of exercise-induced alterations in cytosolic SHP2 and insulin-stimulated Akt pSer(473) on the improvement in insulin sensitivity requires further elucidation.     

Two-dimensional gel electrophoresis database of murine R1 embryonic stem cells

Embryonic stem (ES) cell lines represent a population of undifferentiated pluripotent cells capable of multilineage differentiation in vitro. Although very useful for studying developmental processes, human ES cell lines have also been suggested as a potential and unlimited source for cellular transplantation and the treatment of human disease. The proteomic basis of embryonic stemness (pluripotentiality and multilineage differentiation) and the transitions that lead to specific cell lineages however, remain to be defined. As an important first step in defining these processes, we have performed a proteomic analysis of undifferentiated mouse R1 ES cell lines using pH 3-10, 4-7 and 6-11 two-dimensional electrophoresis gels, matrix-assisted laser desorption/ionization and tandem mass spectrometry. Of the 700 gel spots analyzed, 241 distinct protein species were identified corresponding to 218 unique proteins, with a significant proportion functionally related to protein expression.     

Mapping of citrullinated fibrinogen B-cell epitopes in rheumatoid arthritis by imaging surface plasmon resonance

Introduction  

Rheumatoid arthritis (RA) frequently involves the loss of tolerance to citrullinated antigens, which may play a role in pathogenicity. Citrullinated fibrinogen is commonly found in inflamed synovial tissue and is a frequent target of autoantibodies in RA patients. To obtain insight into the B-cell response to citrullinated fibrinogen in RA, its autoepitopes were systematically mapped using a new methodology.     

Expression of Ca2+-permeable two-pore channels rescues NAADP signalling in TPC-deficient cells

The second messenger NAADP triggers Ca²⁺ release from endo-lysosomes. Although two-pore channels (TPCs) have been proposed to be regulated by NAADP, recent studies have challenged this. By generating the first mouse line with demonstrable absence of both Tpcn1 and Tpcn2 expression (Tpcn1/2^−/−), we show that the loss of endogenous TPCs abolished NAADP-dependent Ca²⁺ responses as assessed by single-cell Ca²⁺ imaging or patch-clamp of single endo-lysosomes. In contrast, currents stimulated by PI(3,5)P₂ were only partially dependent on TPCs. In Tpcn1/2^−/− cells, NAADP sensitivity was restored by re-expressing wild-type TPCs, but not by mutant versions with impaired Ca²⁺-permeability, nor by TRPML1. Another mouse line formerly reported as TPC-null likely expresses truncated TPCs, but we now show that these truncated proteins still support NAADP-induced Ca²⁺ release. High-affinity [³²P]NAADP binding still occurs in Tpcn1/2^−/− tissue, suggesting that NAADP regulation is conferred by an accessory protein. Altogether, our data establish TPCs as Ca²⁺-permeable channels indispensable for NAADP signalling.     

Association of 25-Hydroxyvitamin D status and genetic variation in the vitamin D metabolic pathway with FEV1 in the Framingham Heart Study

Background

Vitamin D is associated with lung function in cross-sectional studies, and vitamin D inadequacy is hypothesized to play a role in the pathogenesis of chronic obstructive pulmonary disease. Further data are needed to clarify the relation between vitamin D status, genetic variation in vitamin D metabolic genes, and cross-sectional and longitudinal changes in lung function in healthy adults.

Methods

We estimated the association between serum 25-hydroxyvitamin D [25(OH)D] and cross-sectional forced expiratory volume in the first second (FEV₁) in Framingham Heart Study (FHS) Offspring and Third Generation participants and the association between serum 25(OH)D and longitudinal change in FEV₁ in Third Generation participants using linear mixed-effects models. Using a gene-based approach, we investigated the association between 241 SNPs in 6 select vitamin D metabolic genes in relation to longitudinal change in FEV₁ in Offspring participants and pursued replication of these findings in a meta-analyzed set of 4 independent cohorts.

Results

We found a positive cross-sectional association between 25(OH)D and FEV₁ in FHS Offspring and Third Generation participants (P = 0.004). There was little or no association between 25(OH)D and longitudinal change in FEV₁ in Third Generation participants (P = 0.97). In Offspring participants, the CYP2R1 gene, hypothesized to influence usual serum 25(OH)D status, was associated with longitudinal change in FEV₁ (gene-based P < 0.05). The most significantly associated SNP from CYP2R1 had a consistent direction of association with FEV₁ in the meta-analyzed set of replication cohorts, but the association did not reach statistical significance thresholds (P = 0.09).

Conclusions

Serum 25(OH)D status was associated with cross-sectional FEV₁, but not longitudinal change in FEV₁. The inconsistent associations may be driven by differences in the groups studied. CYP2R1 demonstrated a gene-based association with longitudinal change in FEV₁ and is a promising candidate gene for further studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-015-0238-y) contains supplementary material, which is available to authorized users.     

Clinical features and predictors for disease natural progression in adults with Pompe disease: a nationwide prospective observational study

Background

Due partly to physicians’ unawareness, many adults with Pompe disease are diagnosed with great delay. Besides, it is not well known which factors influence the rate of disease progression, and thus disease outcome. We delineated the specific clinical features of Pompe disease in adults, and mapped out the distribution and severity of muscle weakness, and the sequence of involvement of the individual muscle groups. Furthermore, we defined the natural disease course and identified prognostic factors for disease progression.

Methods

We conducted a single-center, prospective, observational study. Muscle strength (manual muscle testing, and hand-held dynamometry), muscle function (quick motor function test), and pulmonary function (forced vital capacity in sitting and supine positions) were assessed every 3–6 months and analyzed using repeated-measures ANOVA.

Results

Between October 2004 and August 2009, 94 patients aged between 25 and 75 years were included in the study. Although skeletal muscle weakness was typically distributed in a limb-girdle pattern, many patients had unfamiliar features such as ptosis (23%), bulbar weakness (28%), and scapular winging (33%). During follow-up (average 1.6 years, range 0.5-4.2 years), skeletal muscle strength deteriorated significantly (mean declines of ?1.3% point/year for manual muscle testing and of ?2.6% points/year for hand-held dynamometry; both p<0.001). Longer disease duration (>15 years) and pulmonary involvement (forced vital capacity in sitting position <80%) at study entry predicted faster decline. On average, forced vital capacity in supine position deteriorated by 1.3% points per year (p=0.02). Decline in pulmonary function was consistent across subgroups. Ten percent of patients declined unexpectedly fast.

Conclusions

Recognizing patterns of common and less familiar characteristics in adults with Pompe disease facilitates timely diagnosis. Longer disease duration and reduced pulmonary function stand out as predictors of rapid disease progression, and aid in deciding whether to initiate enzyme replacement therapy, or when.