Water pH and aluminum chemistry in the gill micro-environment of rainbow trout during acid and aluminum exposures

Summary Rainbow trout (Salmo gairdneri) were exposed to acidic soft water (pH_in4.2–6.3) in the presence (93 g·l^–1) or absence of Al. Fish were fitted with latex masks and opercular catheters to measure ventilation , pH changes at the gills, O₂ consumption , ammonia excretion , and Al extraction. During 2–3-h exposures, was generally higher in Al-exposed fish over the pH_in range 4.7–6.3. Alkalinization of expired water was about 0.3 pH units less in Al-exposed fish than in acid-only exposed fish at pH_in 4.5–5.2, an effect attributable to both increased and to buffering by Al. During 44-h exposures to pH_in 5.2 and 4.8 plus Al, increased greatly and expired water pH (pH_ex) decreased with time. There was a small increase in over 44 h at pH 4.4 plus Al, and no changes in pH_ex. In contrast, during 44-h exposures to pH 5.2, 4.8, and 4.4 in the absence of Al, such changes were much smaller or absent. During both short- and longerterm exposures, measured Al accumulation on the gills was only 5–18% of that calculated from cumulative Al extraction from the water, suggesting considerable sloughing of Al. In free-swimming trout, gill Al accumulation was greatest during exposure (2h) to Al at pH 5.2, lower at pH 4.8, and least at pH 4.4 and 4.0. Our results suggest that Al deposition occurs at the gills, causing respiratory and ionoregulatory toxicity, because the pH in the branchial micro-environment is raised above that in the acidic inspired soft water. Higher pH at fish gills may result in Al precipitation due to loss of solubility, or Al accumulation because of shifts in Al species to Al-hydroxide forms which more readily adsorb to the gills.Abbreviations pH _ex expired pH - pH _in inspired pH     

A tetravalent dengue nanoparticle stimulates antibody production in mice

Background

Dengue is a major public health problem worldwide, especially in the tropical and subtropical regions of the world. Infection with a single Dengue virus (DENV) serotype causes a mild, self-limiting febrile illness called dengue fever. However, a subset of patients experiencing secondary infection with a different serotype progresses to the severe form of the disease, dengue hemorrhagic fever/dengue shock syndrome. Currently, there are no licensed vaccines or antiviral drugs to prevent or treat dengue infections. Biodegradable nanoparticles coated with proteins represent a promising method for in vivo delivery of vaccines.

Findings

Here, we used a murine model to evaluate the IgG production after administration of inactivated DENV corresponding to all four serotypes adsorbed to bovine serum albumin nanoparticles. This formulation induced a production of anti-DENV IgG antibodies (p < 0.001). However, plaque reduction neutralization assays with the four DENV serotypes revealed that these antibodies have no neutralizing activity in the dilutions tested.

Conclusions

Our results show that while the nanoparticle system induces humoral responses against DENV, further investigation with different DENV antigens will be required to improve immunogenicity, epitope specicity, and functional activity to make this platform a viable option for DENV vaccines.     

Reassembly of flagellar B (alpha beta) tubulin into singlet microtubules: consequences for cytoplasmic microtubule structure and assembly

B(alpha beta) tubulin was obtained from a homogeneous class of microtubules, the incomplete B subfiber of sea urchin sperm flagellar doublet microtubules, by thermal fractionation. The thermally derived soluble B tubulin fraction (100, 000 g-h) repolymerizes in vitro, yielding microtubule-like structures. The microtubule-associated protein (MAP) composition and certain assembly parameters of thermally derived B tubulin are different from those reported for sonication- derived flageller tubulin and purified vertebrate tubulin. The "microtubules" reassembled from thermally prepared B tubulin are composed of 12-15 protofilaments (73% possess 14 protofilaments). A certain number possess a single "adlumenal component" applied to their inside walls, regardless of the number of protofilaments. Following the first cycle of polymerization, 81% of the B tubulin and essentially 100% of the MAPs remain cold insoluble. Evidence suggests that B tubulin assembles faithfully into a B lattice, creating a j seam between two protofilaments that are laterally bonded in a A-lattice configuration. The significance of these seams is discussed in relation to the mechanism of microtubule assembly, the stability of observed ribbons of protofilaments, and the three-dimensional organization of microtubule-associated components.     

Mechanisms of aluminium extraction and accumulation at the gills of rainbow trout, Oncorhynchus mykiss (Walbaum), in acidic soft water

Rainbow trout were fitted with latex masks for the measurement of ventilatory flow rate (V?_w) and with opercular catheters for sampling expired water from close to the branchial surface. Fish were exposed for 6 h to pH 5.1, 4.7 or 4.1 in the presence (138 μg l ¹) or nominal absence (1 μg 1^–1) of Al. Inspired and expired Al concentrations and water pH were measured via the opercular catheters. Gills were sampled for accumulated Al at the end of the experiments. V?_w increased during Al exposures at all three pHs. However, in the absence of Al, V?_w increased only at pH 4.1. Aluminium extraction from the water and Al accumulation on the gills were highest at inspired pH 5.1 and lowest at pH 4.1, and correlated well with expired pH, which was 0.2–0.7 pH units higher than inspired pH. Gill Al accumulations amounted to only about one-tenth of deposition calculated from Al extraction from the water and V?_w, and gill Al was tightly bound to the branchial surface. Calculations of Al solubility, oversaturation, and species composition were made using measured expired pH values, and were compared with Al extraction from the water and measured gill Al concentrations. In general, these analyses indicated that reduced Al solubility near the gills is a reasonable explanation of Al extraction from the water, and that Al(OH)₂⁺ and Al(OH)₃° are the Al species most likely to interact initially at the gills. It is suggested that mucus sloughing removes most precipitated Al, and that only the charged form persists, bound to structural elements on the gill surface. A model incorporating these results, and pH changes in the fish gill micro-environment in general, is presented to explain previously-reported ionoregulatory and respiratory effects of Al.     

Evidence for subsites in the galectins involved in sugar binding at the nonreducing end of the central galactose of oligosaccharide ligands: sequence analysis, homology modeling and mutagenesis studies of hamster galectin-3

A model of the carbohydrate recognition domain CRD, residues 111-245, of hamster galectin-3 has been made using homology modeling and dynamics minimization methods. The model is based on the known x-ray structures of bovine galectin-1 and human galectin-2. The oligosaccharides NeuNAc-alpha2,3-Gal-beta1,4-Glc and GalNAc-alpha1, 3- [Fuc-alpha1,2]-Gal-beta1,4-Glc, known to be specific high-affinity ligands for galectin-3, as well as lactose recognized by all galectins were docked in the galectin-3 CRD model structure and a minimized binding conformation found in each case. These studies indicate a putative extended carbohydrate-binding subsite in the hamster galectin- 3 involving Arg139, Glu230, and Ser232 for NeuNAc-alpha2,3-; Arg139 and Glu160 for fucose-alpha1,2-; and Arg139 and Ile141 for GalNAc-alpha1,3- substituents on the primary galactose. Each of these positions is variable within the whole galectin family. Two of these residues, Arg139 and Ser232, were selected for mutagenesis to probe their importance in this newly identified putative subsite. Residue 139 adopts main-chain dihedral angles characteristic of an isolated bridge structural feature, while residue 232 is the C-terminal residue of beta- strand-11, and is followed immediately by an inverse gamma-turn. A systematic series of mutant proteins have been prepared to represent the residue variation present in the aligned sequences of galectins-1, - 2, and -3. Minimized docked models were generated for each mutant in complex with NeuNAc-alpha2,3-Gal-beta1,4-Glc, GalNAc-alpha1, 3-[Fuc- alpha1,2]-Gal-beta1,4- Glc, and Gal-beta1,4-Glc. Correlation of the computed protein-carbohydrate interaction energies for each lectin- oligosaccharide pair with the experimentally determined binding affinities for fetuin and asialofetuin or the relative potencies of lactose and sialyllactose in inhibiting binding to asiolofetuin is consistent with the postulated key importance of Arg139 in recognition of the extended sialylated ligand.      

Experience in the application of Java Technologies in telemedicine

Java language has been demonstrated to be an effective tool in supporting medical image viewing in Russia. This evaluation was completed by obtaining a maximum of 20 images, depending on the client's computer workstation from one patient using a commercially available computer tomography (CT) scanner. The images were compared against standard CT images that were viewed at the site of capture. There was no appreciable difference. The client side is a lightweight component that provides an intuitive interface for end users. Each image is loaded in its own thread and the user can begin work after the first image has been loaded. This feature is especially useful on slow connection speed, 9.6 Kbps for example. The server side, which is implemented by the Java Servlet Engine works more effective than common gateway interface (CGI) programs do. Advantages of the Java Technology place this program on the next level of application development. This paper presents a unique application of Java in telemedicine.     

Characteristics of temporal patterns of cortisol and luteinizing hormone in primiparous,postpartum, anovular,suckled, beef cows exposed acutely to bulls

Background  

The physiological mechanism by which bulls stimulate resumption of ovarian cycling activity in postpartum, anovular, suckled cows after calving may involve the concurrent activation of the hypothalamic-hypophyseal-ovarian (HPO) axis and hypothalamic-hypophyseal-adrenal (HPA) axis. Thus, the objectives of this experiment were to determine if characteristics of temporal patterns of cortisol and luteinizing hormone (LH) in postpartum, anovular, beef cows are influenced by acute exposure to bulls. The null hypotheses were that daily, temporal characteristics of cortisol and LH concentration patterns do not differ between cows exposed acutely to bulls or steers.     

Time course analysis of the mechanism by which silver inhibits active Na+ and Cl- uptake in gills of rainbow trout

A time course analysis using (110m)Ag, (24)Na(+), and (36)Cl(-) examined gill silver accumulation and the mechanism by which waterborne silver (4.0 x 10(-8) M; 4.3 microg/l) inhibits Na(+) and Cl(-) uptake in gills of freshwater rainbow trout. Analyses of gill and body fluxes allowed calculation of apical uptake and basolateral export rates for silver, Na(+), and Cl(-). To avoid changes in silver bioavailability, flow-through conditions were used to limit the buildup of organic matter in the exposure water. For both Na(+) and Cl(-) uptake, apical entry, rather than basolateral export, was the rate-limiting step; Na(+) and Cl(-) uptake declined simultaneously and equally initially, with both uptakes reduced by approximately 500 nmol.g(-1).h(-1) over the 1st h of silver exposure. There was a further progressive decline in Na(+) uptake until 24 h. Carbonic anhydrase activity was inhibited by 1 h, whereas Na(+)-K(+)-ATPase activity was not significantly inhibited until 24 h of exposure. These results indicate that carbonic anhydrase inhibition can explain the early decline in Na(+) and Cl(-) uptake, whereas the later decline is probably related to Na(+)-K(+)-ATPase blockade. Contrary to previous reports, gill silver accumulation increased steadily to a plateau. Despite the rapid inhibition of apical Na(+) and Cl(-) uptake, apical silver uptake (and basolateral export) increased until 10 h, before decreasing thereafter. Thus silver did not inhibit its own apical uptake in the short term. These results suggest that reduced silver bioavailability is the mechanism behind the pattern of peak and decline in gill silver accumulation previously reported for static exposures to silver.     

Lung function,symptoms and inflammation during exacerbations of non-cystic fibrosis bronchiectasis: a prospective observational cohort study

Background

Exacerbations of non-cystic fibrosis bronchiectasis cause significant morbidity but there are few detailed data on their clinical course and associated physiological changes. The biology of an exacerbation has not been previously described.The purpose of this study was to describe changes in lung function, symptoms, health status and inflammation during the development and recovery from community-treated exacerbations.

Methods

This was a prospective observational cohort study of 32 outpatients with non-cystic fibrosis bronchiectasis conducted between August 2010 and August 2012. Patients completed a symptom diary card and measured their peak expiratory flow rate (PEFR) daily. Exacerbations were defined as oral antibiotic treatment taken for a worsening of respiratory symptoms. Symptoms and peak flow at exacerbation were analysed, and further measurements including the COPD Assessment Test (CAT) and inflammatory markers were also compared to baseline values.

Results

At baseline, health status was significantly related to lung function, prognostic severity and systemic inflammation. 51 exacerbations occurred in 22 patients. Exacerbation symptoms began a median (interquartile range) of 4 (2, 7) days before treatment started and the median exacerbation duration was 16 (10, 29) days. 16% had not recovered by 35 days. At exacerbation, mean PEFR dropped by 10.6% (95% confidence interval 6.9-14.2, p < 0.001) and mean CAT score increased by 6.3 units (3.6-9.1, p = 0.001), median symptom count by 4 (2.25, 6, p < 0.001), and mean CRP by 9.0mg/L (2.3-15.8, p = 0.011). Exacerbations where PEFR fell by ≥10% were longer with more symptoms at onset.

Conclusion

Exacerbations of non-CF bronchiectasis are inflammatory events, with worsened symptoms, lung function and health status, and a prolonged recovery period. Symptom diary cards, PEFR and CAT scores are responsive to changes at exacerbation and may be useful tools for their detection and monitoring.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-015-0167-9) contains supplementary material, which is available to authorized users.     

On the origins of esterases

Comparisons among the primary sequences of five cloned eukaryotic esterases reveal two distinct lineages, neither bearing any significant overall sequence similarity to the functionally related serine protease multigene family. We have not eliminated the possibility that the esterases may have residual conformational similarities to the serine proteases. However, our profile analysis and analyses of the predicted conformations of the esterases reveal little similarity to the serine proteases. Four of the esterase proteins share 27%-53% overall sequence similarity and evidence of a catalytic mechanism involving the same Arg- Asp-Ser or His-Asp-Ser charge relay. We propose that these four esterases, three of them cholinesterases, form part of a multigene family essentially separate from the serine proteases.