DNA Coated Nanoparticle Eight-mers as Programmable Self-Assembly Building Blocks

Abstract. Nanoparticles coated with single stranded DNA have been shown to efficiently hybridize to targets of complementary DNA. This property might be used to implement programmable (or algorithmic-) self-assembly to build nanoparticle structures. However, we argue that a DNA coated nanoparticle by itself cannot be used as a programmable self-assembly building block since it does not have directed bonds. A general scheme for assembling and purifying nanoparticle eight-mers with eight geometrically well-directed bonds is presented together with some preliminary experimental work

Ser649 and Ser650 Are the Major Determinants of Protein Kinase A-Mediated Activation of Human Hormone-Sensitive Lipase against Lipid Substrates

BACKGROUND: Hormone-sensitive lipase (HSL) is a key enzyme in the mobilization of fatty acids from stored triacylglycerols. Its activity is regulated by reversible protein phosphorylation. In rat HSL Ser563, Ser659 and Ser660 have been shown to be phosphorylated by protein kinase A (PKA) in vitro as well as in vivo. METHODOLOGY/PRINCIPAL FINDINGS: In this study we employed site-directed mutagenesis, in vitro phosphorylation and mass spectrometry to show that in vitro phosphorylation of human HSL by PKA occurs primarily on Ser649 and Ser650 (Ser659 and Ser660 in rat HSL). The wild type enzyme and four mutants were expressed in C-terminally His-tagged form in Sf9 insect cells and purified to homogeneity. HSL variants in which Ser552 and/or Ser554 were mutated to Ala or Glu retained both lipolytic and non-lipolytic activity and were phosphorylated by PKA and activated to a similar extent as the wild type enzyme. (32)P-labeling studies revealed that the bulk of the phosphorylation was on the Ser649/Ser650 site, with only a minor phosphorylation of Ser552 and Ser554. MS/MS analysis demonstrated that the peptide containing Ser649 and Ser650 was primarily phosphorylated on Ser650. The mutant lacking all four serines had severely reduced lipolytic activity, but a lesser reduction in non-lipolytic activity, had S(0.5) values for p-nitrophenol butyrate and triolein comparable to those of wild type HSL and was not phosphorylated by PKA. PKA phosphorylation of the wild type enzyme resulted in an increase in both the maximum turnover and S(0,5) using the TO substrate. CONCLUSIONS: Our results demonstrate that PKA activates human HSL against lipid substrates in vitro primarily through phosphorylation of Ser649 and Ser650. In addition the results suggest that Ser649 and Ser650 are located in the vicinity of a lipid binding region and that PKA phosphorylation controls the accessibility of this region

Vägen tillbaka - om socialtjänsten, Försäkringskassan och de långtidssjukskrivna

Socialtjänstens arbete med arbetslivsinriktad rehabilitering är omfattande och har på senare år kommit att få en växande betydelse genom att allt fler långtidssjuka står utan både arbete och socialförsäkringsskydd. Det finns emellertid mycket lite översiktlig kunskap om hur denna verksamhet fungerar i de svenska kommunerna. I denna rapport undersöks hur socialtjänsten arbetar med långtidssjuka personer som är nollklassade hos Försäkringskassan. En forskningsöversikt görs om orsakerna till de höga sjuktalen i Sverige och vilka faktorer som kan påverka långtidssjukas möjligheter att komma tillbaka till arbetslivet. Vidare diskuteras Försäkringskassans, Arbetsmarknadsverkets, arbetsgivarnas och landstingens rehabiliteringsansvar. Därefter studeras, främst genom chefsintervjuer, hur arbetslivsinriktad rehabilitering organiseras inom socialtjänsten i Stockholms stad och fem av stadsdelsförvaltningarna. Avslutningsvis diskuteras vilka konsekvenser den samhälleliga arbetslinjen och organisationen av rehabilitering kan ha för långtidssjuka människor idag

Om barnfattigdom - ansvar, insatser och orsaker

Denna rapport syftar till att ge en flervetenskaplig belysning av olika aspekter av barnfattigdom i dagens Sverige och i Stockholm. Perspektiven är historiska, juridiska, politiska, ekonomiska och sociala. I en historisk jämförelse framträder bl a att barnen under det senaste halvseklet kommit att bli allt mera överrepresenterade bland dem som får ekonomiskt bistånd i Sverige. De juridiska aspekterna av samhällets ansvar problematiseras i relation till tolkningen av FN:s Barnkonvention. Uppgiftsfördelningen mellan överstatliga och mellanstatliga organ, svenska staten och de svenska kommunerna är emellertid oklar på flera punkter. Detta bidrar till att det kan bli svårt att uppfylla EU:s mål att utrota barnfattigdomen till 2010. Ett stort ansvar ligger på kommunerna, som emellertid har små möjligheter att strategiskt påverka barnfattigdomen. En närmare studie av Stockholms stad visar bl a på en fortgående process av segregation mellan stadsdelarna. Samtidigt som barnperspektivet blivit tydligare i de kommunala verksamheterna de senaste åren, kvarstår stora svårigheter att agera långsiktigt inom dessa verksamheter. Avslutningsvis diskuteras ämnesövergripande och ideologiska aspekter av arbetet mot barnfattigdom

Characterization of the Lipid Droplet Proteome of a Clonal Insulin-producing β-Cell Line (INS-1 832/13).

Lipids are known to play a crucial role both in the normal control of insulin release and in the deterioration of β-cell function, as observed in type 2 diabetes. Despite this established dual role of lipids, little is known about lipid storage and handling in β-cells. Here, we isolated lipid droplets from oleate-incubated INS-1 832/13 cells and characterized the lipid droplet proteome. In a total of four rounds of droplet isolation and proteomic analysis by HPLC-MS/MS, we identified 96 proteins that were specific to droplets. The proteins fall into six categories based on function or previously observed localization: metabolism, endoplasmic reticulum/ribosomes, mitochondria, vesicle formation and transport, signaling, and miscellaneous. The protein profile reinforces the emerging picture of the lipid droplet as an active and dynamic organelle involved in lipid homeostasis and intracellular trafficking. Proteins belonging to the category mitochondria were highly represented, suggesting that the β-cell mitochondria and lipid droplets form a metabolic unit of potential relevance for insulin secretion

Oxidative stress response plays a role in antibiotic tolerance of <i>Streptococcus mutans</i> biofilms

Knowledge about biofilm-associated antibiotic tolerance mechanisms is warranted in order to develop effective treatments against biofilm infections. We performed a screen of a Streptococcus mutans transposon mutant library for mutants with reduced biofilm-associated antimicrobial tolerance, and found that the spxA1 gene plays a role in tolerance towards gentamicin and other antibiotics such as vancomycin and linezolid. SpxA1 is a regulator of genes involved in the oxidative stress response in S. mutans. The oxidative stress response genes gor and ahpC were found to be up-regulated upon antibiotic treatment of S. mutans wild-type biofilms, but not spxA1 mutant biofilms. The gor gene product catalyses the formation of glutathione which functions as an important antioxidant during oxidative stress, and accordingly biofilm-associated antibiotic tolerance of the spxA1 mutant could be restored by exogenous addition of glutathione. Our results indicate that the oxidative stress response plays a role in biofilm-associated antibiotic tolerance of S. mutans, and add to the on-going debate on the role of reactive oxygen species in antibiotic mediated killing of bacteria.Published versio

Polluted lignocellulose-bearing sediments as a resource for marketable goods—a review of potential technologies for biochemical and thermochemical processing and remediation

Lignocellulose-bearing sediments are legacies of the previously unregulated wastewater discharge from the pulp and paper industry, causing large quantities of toxic organic waste on the Baltic Sea floor and on the bottom of rivers and lakes. Several km2 are covered with deposits of lignocellulosic residues, typically heavily contaminated with complex mixtures of organic and inorganic pollutants, posing a serious threat to human and ecological health. The high toxicity and the large volume of the polluted material are challenges for remediation endeavours. The lignocellulosic material is also a considerable bioresource with a high energy density, and due to its quantity, it could appeal to commercialization as feedstock for various marketable goods. This study sets out to explore the potential of using this polluted material as a resource for industrial production at the same time as it is detoxified. Information about modern production methods for lignocellulosic material that can be adapted to a polluted feedstock is reviewed. Biochemical methods such as composting, anaerobic digestion, as well as, thermochemical methods, for instance, HTC, HTL, pyrolysis, gasification and torrefaction have been assessed. Potential products from lignocellulose-bearing sediment material include biochar, liquid and gaseous biofuels, growing substrate. The use of a contaminated feedstock may make the process more expensive, but the suggested methods should be seen as an alternative to remediation methods that only involve costs. Several experiments were highlighted that support the conception that combined remediation and generation of marketable goods may be an appropriate way to address polluted lignocellulose-bearing sediments. Graphic abstract: [Figure not available: see fulltext.]