Size and shape of the repetitive domain of high molecular weight wheat gluten proteins. 1. Small angle neutron scattering

The solution structure of the central repetitive domain of high molecular weight (HMW) wheat gluten proteins has been investigated for a range of concentrations and temperatures using mainly small-angle neutron scattering. A representative part of the repetitive domain (dBl) was studied as well as an "oligomer" basically consisting of four dBl units, which has a length similar to the complete central domain. The scattering data over the entire angular range of both proteins are in quantitative agreement with a structural model based on a worm-like chain, a model frequently used in polymer theory. This model describes the "supersecondary, structure" of dBl and dB4 as a semiflexible cylinder with a length of about 235 and 900 Angstrom, respectively, and a cross-sectional diameter of about 15 Angstrom. The flexibility of both proteins is characterized by a persistence length of about 13 Angstrom. Their structures are thus quantitatively identical, which implies that the central HMW domain can be elongated while retaining its structural characteristics. It seems conceivable that the flexible cylinder results from a helical structure, which resembles the beta-spiral observed in earlier studies on gluten proteins and elastin. However, compared to the previously, proposed structure of a (stiff) rod, our experiments clearly indicate flexibility of the cylinder. (C) 2003 Wiley Periodicals, Inc

Probing the self-assembly and the accompanying structural changes of hydrophobin SC3 on a hydrophobic surface by mass spectrometry

The fungal class I hydrophobin SC3 self-assembles into an amphipathic membrane at hydrophilic-hydrophobic interfaces such as the water-air and water-Teflon interface. During self-assembly, the water-soluble state of SC3 proceeds via the intermediate alpha-helical state to the stable end form called the beta-sheet state. Self-assembly of the hydrophobin at the Teflon surface is arrested in the alpha-helical state. The beta-sheet state can be induced at elevated temperature in the presence of detergent. The structural changes of SC3 were monitored by various mass spectrometry techniques. We show that the so-called second loop of SC3 (C39-S72) has a high affinity for Teflon. Binding of this part of SC3 to Teflon was accompanied by the formation of alpha-helical structure and resulted in low solvent accessibility. The solvent-protected region of the second loop extended upon conversion to the beta-sheet state. In contrast, the C-terminal part of SC3 became more exposed to the solvent. The results indicate that the second loop of class I hydrophobins plays a pivotal role in self-assembly at the hydrophilic-hydrophobic interface. Of interest, this loop is much smaller in case of class II hydrophobins, which may explain the differences in their assembly

Förväntningar på bildämnet - En analys av bildämnet på formuleringsarenan genom läroplanerna från 1969, 1980, 1994 och 2011

Syftet med det här arbetet är att undersöka hur förväntningarna på bildämnet har sett ut, såsom de framkommer av läroplanerna från 1969, 1980, 1994 och 2011. Syftet är vidare att se vilka likheter och skillnader det finns mellan dessa och att se hur utvecklingslinjer från tidigare forskning visar sig i dem. Arbetet tar sin utgångspunkt i den tidigare forskning som gjorts av Gunnar Åsén. Det är ur hans forskning jag utläst utvecklingslinjerna. Undersökningen har genomförts genom en kvalitativ innehållsanalys. Av tidigare forskning har jag utläst åtta utvecklingslinjer i tecknings-/bildämnets historia och utifrån dessa analyserar jag ovan nämnda läroplaner. Undersökningen är också komparerande, jag jämför de fyra läroplanernas innehåll för att få fram skillnader och likheter i deras innehåll. Resultatet visar både stora likheter och stora skillnader mellan läroplanerna och bildämnet. Likheterna ligger i att innehållet har varit något sånär detsamma, ungefär samma moment ingår i alla fyra läroplaner. Skillnaderna ligger i hur mycket utrymme dessa moment får och hur stor vikt som läggs på dem. Ämnets kommunikativa inslag var till exempel ganska begränsade Lgr 69 medan de i Lgr 11 genomsyrar det mesta. Tvärtom med det fria skapandet. Resultatet visar också att bildämnet blivit något helt annat än det var vid dess tillkomst på 1800- talet. Då var motiveringarna till ämnet baserade på dess yrkeskvalificering och behov av kunskaper inom teknisk ritning, nu är ämnet framför allt kommunikativt och snarare konsumentkvalificerande. När jag satte de undersökta läroplanerna i relation till ämnets historia och de utvecklingslinjer jag läst ut av tidigare forskning så framgick också att inget nytt innehåll har tillkommit sedan Lgr 69

Medarbetarskap i förskolan.

Chemical modification procedures have been used to study the interaction of tricyclic and non-tricyclic 5HT-reuptake inhibitors with the [3H]imipramine binding site (IBS). N-Ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) induced a pronounced loss in [3H]imipramine binding due to a reduction in Bmax. Preincubation with reuptake inhibitors and subsequent inactivation by EEDQ revealed that imipramine and 5HT prevented the EEDQ-induced inhibition, but citalopram and fluoxetine did not. Thiol modification studies demonstrated that reduction by dithiothreitol (DTT) enhanced the binding of [3H]imipramine by increasing the Bmax. The thioselective reagents 1,1-diaxobis-(N,N-dimethylformamide) (diamide), phenyl-arsineoxide (PAO) and N-ethylmaleimide (NEM) attenuated the binding capacity by lowering the Bmax. PAO, a reversible thiol reagent, prevented NEM alkylation indicating that dithiols are involved in the NEM-induced inactivation. Binding of tricyclics or non-tricyclics prior to PAO inactivation revealed that tricyclics provide complete protection against thiol modification, while the non-tricyclics do not. The results support the hypothesis that the 5HT-reuptake system of human platelets possesses at least two distinguishable binding sites.