Some effects of polyvinyl alcohol and polyvinyl pyrrolidone on the activity of lactate dehydrogenase and its isoenzymes

Summary The activity of Sigma type II LDH (containing all LDH isoenzymes), type VII (LDH 1) and type V (LDH 5) has been evaluated in 0.1 M phosphate buffer and 0.4 M tris-HCl buffer, both at pH 7.4, before and after addition of PVP and PVA. A slight reduction of reaction velocity occurred when PVP and PVA were added, probably because of the increased viscosity of the medium. More specifically, PVA seemed to reduce the LDH 1 activity in phosphate buffer, but it seemed to counteract, together with PVP, conformational changes due to tris-HCl buffer of high molarity. None of these effects were found to influence the results of section histochemistry, but it could be shown that PVA was able to reduce urea inhibition of LDH 5 in tris-HCl buffer.The following Abbreviations are used in the Article PVA Polyvinyl alcohol - PVP Polyvinyl pyrrolidone - tris tris (hydroxymethyl)-aminomethan - LDH Lactate dehydrogenase - -NADH -Nicotinamide Adenine Dinucleotide, reduced form - PMS Phenazine methosulfate - BSA Bovine serum albumin     

Genes of the R-phycocyanin II locus of marine Synechococcus spp., and comparison of protein-chromophore interactions in phycocyanins differing in bilin composition

R-phycocyanin II (RPCII) is a recently discovered member of the phycocyanin family of photosynthetic light-harvesting proteins. Genes encoding the and subunits of RPCII were cloned and sequenced from marine Synechococcus sp. strains WH8020 and WH8103. The deduced amino acid sequences of RPCII were compared to two other types of phycocyanin, C-phycocyanin (CPC) and phycoerythrocyanin (PEC). These three types vary in the composition of their covalently bound bilin prosthetic groups. In terms of amino acid sequence identity RPCII is highly homologous to CPC and PEC, suggesting that the known three-dimensional structures of the latter two are representative of RPCII. Thus the amino acid residues contacting the three bilins of RPCII could be inferred and compared to those in CPC and PEC. Certain residues were identified among the three phycocyanins as possibly correlating with specific bilin isomers. In overall sequence RPCII and CPC are more homologous to one another than either is to PEC. This probably reflects functional homology in the roles of RPCII and CPC in the transfer of light energy to the core of the phycobilisome, a function not attributed to PEC. The genomes of Synechococcus sp. strains WH8020, WH8103 and WH7803 share homologous open reading frames in the vicinity of RPCII genes. The nucleotide sequence extending 3 from RPCII genes in strain WH8020 revealed two open reading frames homologous to components of an CPC phycocyanobilin lyase. These open reading frames may encode a lyase specific for the attachment of phycoerythrobilin to RPCII.     

Nest distribution shaping within-stream variation in Atlantic salmon juvenile abundance and competition over small spatial scales

1. Spatial heterogeneity in population density is predicted to have important effects on population characteristics, such as competition intensity and carrying capacity. Patchy breeding distributions will tend to increase spatial heterogeneity in population density, whereas dispersal from breeding patches will tend to decrease it. The potential for dispersal to homogenize densities is likely to differ both among organisms (e.g. plants vs. mobile animals) and throughout ontogeny (e.g. larvae vs. adults). However, for mobile organisms, experimental studies of the importance of breeding distributions from the wild are largely lacking. 2. In the present study, experimental manipulations replicated over eight natural streams and 2 years enabled us to test for effects of the distribution of Atlantic salmon eggs over spatial scales which are relevant to local interactions among individuals. Artificial nests were placed along 250 m study reaches at one of two levels of nest dispersion - patchy (two nests per stream) and dispersed (10 nests per stream) - while holding total egg density (eggs m(-2) stream area) constant. 3. Nest dispersion had significant effects on the spatial distribution of the resulting juveniles in their first summer. Patchy nest distributions resulted in a highly right-skewed frequency distribution of local under-yearling densities (among 25 m sampling sections), as sample sections adjacent to the nest sites had relatively high densities. In contrast, dispersed nest distributions yielded approximately normal density distributions. Sections with high relative densities in the patchy nest distribution treatments also had relatively small juvenile body sizes, and patchy egg distribution appeared to produce a higher redistribution of individuals from the first to the second juvenile growth season than the dispersed distribution. 4. Because patchy breeding distribution combined with limited early dispersal can create spatial variation in density over scales directly relevant for individual interactions, this will be one important component in determining mean levels of early juvenile competition and its spatial variation within populations. Assuming random or ideal-free distribution of individuals may therefore underestimate the mean level of density experienced by juveniles over surprisingly small spatial scales (orders of magnitude smaller than total spatial extent of populations), even for mobile organisms.     

Side-chain modified analogues of histaprodifen: asymmetric synthesis and histamine H1-receptor activity

New analogues of histaprodifen with polar side chains have been stereoselectively synthesized and evaluated as histamine H(1)-receptor agonists. As a key transformation the asymmetric aminohydroxylation has been used, which was successfully realized for the first time on an imidazolyl derivative. While all chiral analogues proved to be weak H(1)-receptor antagonists, an achiral keto derivative of histaprodifen turned out to be the first 2-acylated histamine congener displaying partial H(1)-receptor agonism (relative potency 12%).     

An Australian Multi‐Regional Waste Supply‐Use Framework

The production of waste creates both direct and indirect environmental impacts. A range of strategies are available to reduce the generation of waste by industry and households, and to select waste treatment approaches that minimize environmental harm. However, evaluating these strategies requires reliable and detailed data on waste production and treatment. Unfortunately, published Australian waste data are typically highly aggregated, published by a variety of entities in different formats, and do not form a complete time‐series. We demonstrate a technique for constructing a multi‐regional waste supply‐use (MRWSU) framework for Australia using information from numerous waste data sources. This is the first MRWSU framework to be constructed (to the authors' knowledge) and the first sub‐national waste input‐output framework to be constructed for Australia. We construct the framework using the Industrial Ecology Virtual Laboratory (IELab), a cloud‐hosted computational platform for building Australian multi‐regional input‐output tables. The structure of the framework complies with the System of Environmental‐Economic Accounting (SEEA). We demonstrate the use of the MRWSU framework by calculating waste footprints that enumerate the full supply chain waste production for Australian consumers.     

Differential effects of proinflammatory cytokines on cell death and ER stress in insulin-secreting INS1E cells and the involvement of nitric oxide

Proinflammatory cytokines produced by immune cells destroy pancreatic beta cells in type 1 diabetes. The aim of this study was to investigate the cytokine network and its effects in insulin-secreting cells. INS1E cells were exposed to different combinations of proinflammatory cytokines. Cytokine toxicity was estimated by MTT assay and caspase activation measurements. The NFκB-iNOS pathway was analyzed by a SEAP reporter gene assay, Western-blotting and nitrite measurements. Gene expression analyses of ER stress markers, Chop and Bip, were performed by real-time RT-PCR. Cytokines tested in this study, namely IL-1β, TNFα and IFNγ, had deleterious effects on beta cell viability. The most potent toxicity exhibited IL-1β and its combinations with other cytokines. The toxic effects of IL-1β towards cell viability, caspase activation and iNOS activity were dependent on nitric oxide and abolished by an iNOS blocker. IL-1β was the strongest inducer of the NFκB activation. An iNOS blocker inhibited IL-1β-mediated NFκB activation in the first, initial phase of cytokine action, but did not affect significantly NFκB activation after prolonged incubation. Interestingly iNOS protein expression was induced predominantly by IL-1β and decreased in the presence of an iNOS blocker in the case of a short time exposure. The changes in the expression of ER stress markers were also almost exclusively dependent on the IL-1β presence and counteracted by iNOS blockade. Thus cytokine-induced beta cell death is primarily IL-1β mediated with a NO-independent enhancement by TNFα and IFNγ. The deleterious effects on cell viability and function are crucially dependent on IL-1β-induced nitric oxide formation.     

Companies on the Scale

A determination of the sustainability performance of a company ought to fulfill certain requirements. It has to take into account the direct impacts from on-site processes as well as indirect impacts embodied in the supply chains of a company. This life cycle thinking is the common theme of popular footprint analyses, such as carbon, ecological, or water footprinting. All these indicators can be incorporated into one common and consistent accounting and reporting scheme based on economic input−output analysis, extended with data from all three dimensions of sustainability. We introduce such a triple-bottom-line accounting framework and software tool and apply it in a case study of a small company in the United Kingdom. Results include absolute impacts and relative intensities of indicators and are put into perspective by a benchmark comparison with the economic sector to which the company belongs. Production layer decomposition and structural path analysis provide further valuable detail, identifying the amount and location of triple-bottom-line impacts in individual upstream supply chains. The concept of shared responsibility has been applied to avoid double-counting and noncomparability of results. Although in this work we employ a single-region model for the sake of illustration, we discuss how to extend our ideas to international supply chains. We discuss the limitations of the approach and the implications for corporate sustainability.     

Antiarrhythmic drugs impair hepatic uptake and secretory function by different mechanisms in the isolated perfused rat liver

In the present study the effect of various antiarrhythmic drugs on hepatic perfusion parameters, uptake capacity of organic anions and biliary secretion using the isolated perfused rat liver was examined. Infusion of verapamil (VP), diltiazem, N-propyl-ajmaline (NPAB), and quinidine at pharmacological doses induced consistently a 1.4-1.6-fold increase in portal pressure accompanied by a approximately 60% decrease in bile flow and a approximately 65% inhibition of biliary taurocholate (TC) excretion. Furthermore, hepatic uptake of oxygen, bromosulphthalein (BSP), and TC was significantly reduced. All these effects were dose-dependent and reversible upon withdrawal of the drugs. Studies of the hepatic circulation using a Trypan blue staining technique demonstrated a patchy perfusion pattern during infusion of the antiarrhythmic drugs as compared to the homogenously stained control organ. The hemodynamic alterations and the impairment of the hepatic initial uptake function could be entirely prevented by concomitant administration of the vasodilator papaverine. Bile flow and biliary TC excretion, however, were still inhibited under these conditions. The present results indicate that antiarrhythmic drugs produce cholestasis in the isolated perfused rat liver independently of their adverse effect on hepatic hemodynamics.