Benefits and constrains of covalency: the role of loop length in protein stability and ligand binding

Protein folding is governed by non-covalent interactions under the benefits and constraints of the covalent linkage of the backbone chain. In the current work we investigate the influence of loop length variation on the free energies of folding and ligand binding in a small globular single-domain protein containing two EF-hand subdomains-calbindin D-9k. We introduce a linker extension between the subdomains and vary its length between 1 to 16 glycine residues. We find a close to linear relationship between the linker length and the free energy of folding of the Ca2+-free protein. In contrast, the linker length has only a marginal effect on the Ca2+ affinity and cooperativity. The variant with a single-glycine extension displays slightly increased Ca2+ affinity, suggesting that the slightly extended linker allows optimized packing of the Ca2+-bound state. For the extreme case of disconnected subdomains, Ca2+ binding becomes coupled to folding and assembly. Still, a high affinity between the EF-hands causes the non-covalent pair to retain a relatively high apparent Ca2+ affinity. Our results imply that loop length variation could be an evolutionary option for modulating properties such as protein stability and turnover without compromising the energetics of the specific function of the protein

New Initiatives for Building Education for Sustainability in Initial Early Childhood Teacher Education in Sweden – Critical Aspects and Noticeable Needs

There is an identified need for research capable of enhancing understanding of effective practice in the embedding of Education for Sustainability (EfS) in Initial Early Childhood Teacher education (IECTE). Research further finds that innovative teaching strategies are needed to build new teachers’ capacity to prepare future citizens to manage critical sustainability challenges. This study meets this need by investigating how EfS is implemented in two IECTE programmes at two Swedish universities where EfS is embedded throughout the years of study, and the learning students demonstrate at the end of the programmes in relation to EfS. Findings reveal that students demonstrate a range of understandings related to EfS and the role of the early childhood teacher in EfS. Findings further suggest there is an overall need to deepen IECTE students’ EfS theoretical and pedagogical content knowledge to enable them to close a gap between the theory and teaching of EfS in early childhood education settings

100% complete assignment of non-labile 1H, 13C, and 15N signals for calcium-loaded calbindin D9k P43G

Here we present the 100% complete assignment chemical shift of non-labile 1H, 15N and 13C nuclei of Calbindin D9k P43G. The assignment includes all non-exchangeable side chain nuclei, including ones that are rarely reported, such as LysNζ as well as the termini. NMR experiments required to achieve truly complete assignments are discussed. To the best of our knowledge our assignments for Calbindin D9k extend beyond previous studies reaching near-completeness (Vis et al. in Biochem 33:14858–14870, 1994; Yamazaki et al. in J Am Chem Soc 116:6464–6465, 1994; Yamazaki et al. in Biochem 32:5656–5669, 1993b)

Molecular Determinants of S100B Oligomer Formation

Background: S100B is a dimeric protein that can form tetramers, hexamers and higher order oligomers. These forms have been suggested to play a role in RAGE activation. Methodology/Principal Findings: Oligomerization was found to require a low molecular weight trigger/cofactor and could not be detected for highly pure dimer, irrespective of handling. Imidazol was identified as a substance that can serve this role. Oligomerization is dependent on both the imidazol concentration and pH, with optima around 90 mM imidazol and pH 7, respectively. No oligomerization was observed above pH 8, thus the protonated form of imidazol is the active species in promoting assembly of dimers to higher species. However, disulfide bonds are not involved and the process is independent of redox potential. The process was also found to be independent of whether Ca 2+ is bound to the protein or not. Tetramers that are purified from dimers and imidazol by gel filtration are kinetically stable, but dissociate into dimers upon heating. Dimers do not revert to tetramer and higher oligomer unless imidazol is again added. Both tetramers and hexamers bind the target peptide from p53 with retained stoichiometry of one peptide per S100B monomer, and with high affinity (lgK = 7.360.2 and 7.260.2, respectively in 10 mM BisTris, 5 mM CaCl 2, pH 7.0), which is less than one order of magnitude reduced compared to dimer under the same buffer conditions. Conclusion/Significance: S100B oligomerization requires protonated imidazol as a trigger/cofactor. Oligomers ar

Kvalitet i barnehagelærerutdanning i naturvitenskap: En fellesnordisk studiemodul

This article presents a new joint Nordic study module consisting of a theoretical framework, the kindergarten teacher students’ case study and a reflection talk, in natural science for the kinder-garten teacher education. The module is developed through an interdisciplinary collaboration in the Nordplus network: Learning of science concepts by kindergarten children: Nordic study module for the kindergarten teacher education (NATGREP), with science and quality in the kindergarten teacher education in focus. The introduction describes the Nordic kindergartens shortly, and concepts as quality and competence are shortly discussed. It is followed by the module’s theoretical framework. Then the study module’s development process is described accompanied by reflections of the student’s case studies in relation to the theoretical framework. At the end, the work with the study module is summarised, and the main conclusion is that the study module contributes positively to the students’ skills development, both in science and quality

Ungdomars användning av dator, internet och mobiltelefon - Konsekvenser för vardagslivets geografiska dimensioner

SAMMANFATTNING Syftet med denna rapport är att undersöka hur ungdomar i sin vardag använder sig av olika former av informations- och kommunikationsteknologi (IKT: dator, internet, mobil och fast telefon) och hur användningen påverkar vardagslivets geografiska dimensioner. Dessa dimensioner omfattar dels människors fysiska resor och aktivitetsmönster och dels virtuella kontakter och deras geografiska utsträckning. Följande forskningsfrågor behandlas. I vilken omfattning och till vilka ändamål använder ungdomar IKT i vardagslag? Förknippas allt fler av vardagens sysslor med att man använder IKT? Hur utnyttjas IKT-baserade möjligheter i relation till mer traditionella resbaserade; kompletterar eller substituerar de varandra? Påverkar användningen av IKT ungdomarnas aktivitetsmönster, rörlighet och virtuella kontakter? Det empiriska underlaget utgörs av två undersökningar. För det första en intensiv studie av 43 gymnasieungdomar i Göteborg. Dessa har undersökts med hjälp av aktivitetsdagböcker (DBU) och strukturerade intervjuer. För det andra en extensiv undersökning som utnyttjar data från fyra nationella kommunikationsvaneundersökningar (KOM) från åren 1997 till 2000. Dessa ger en mer generell bild av svenska ungdomars IKT-användning. Empiriska resultat som presenteras i rapporten visar bl.a. att den genomsnittliga användningen av IKT är hög. Gymnasieungdomarna använder dator i genomsnitt 1 timma per dag. Internet används ca 30 minuter per dag enligt både KOM och DBU. Samtidigt är det en minoritet av ungdomarna som faktiskt använder sig av internet en vanlig dag. Detta tyder på stora variationer i användningen. Ungdomarnas dator- och internetanvändning domineras av nöje, skolarbete och social kommunikation med vänner och familj. Men man kan urskilja olika typer av IKT-användare. Medan vissa har en nöjesorienterad användning har andra en helt och hållet nyttoorienterad. De ungdomar som ägnar mycket tid till internet är ungdomar vars användning till stor del handlar om underhållning och förströelse. Av den totala mobilanvändingen utgörs 40 % av SMS. Även här finner man stora variationer i användningens omfattning. IKT-baserade aktiviteter (t.ex. ordbehandling, spel, ladda ner/lyssna på musik, nöjessurfa, chatta) utgör i första hand kompletterande alternativt nya aktiviteter i ungdomarnas vardag. Konsekvenser för aktivitetsmönster är främst relaterade till dess påverkan på ungdomarnas tidsanvändning. Det är tydligt hur datorn upptar många ungdomars tid. Det framgår dock att det främst är andra aktiviteter i hemmet som påverkas då mer tid ägnas åt dator och internet. Då IKT-baserade aktiviteter substituerar andra aktiviteter är det främst redan IKT-baserade (dvs telefonbaserade) aktiviteter som berörs. Konsekvenser för ungdomarnas aktivitetsmönster i geografisk bemärkelse är således marginella

Ungdomars virtuella rörlighet - Användningen av dator, internet och mobiltelefon i ett geografiskt perspektiv

This study explores how urban young people fit the use of information and communication technologies (ICT) into their everyday lives. Their virtual mobility may be lasting and have long-term effects on socio-spatial structures. The specific aim of this thesis is to examine the actual use of ICT in young people’s everyday lives, and to analyse the social and geographical dimensions of this use. The thesis focuses on the following research issues: 1) evolving patterns of access to and use of computers, the Internet, and mobile phones among young people in Sweden; 2) the Internet as a new means of communication, and how it affects the social and geographical patterns of interpersonal contacts; 3) the interplay between various forms of geographical mobility – virtual, physical, and media-related; and 4) how computer use as a new domestic leisure activity may affect how and where young people spend their free time. The theoretical approach emphasises the role of the user and how her or his daily activity patterns shape the geographical implications of ICT. Detailed insight into actual ICT use was obtained via a longitudinal in-depth investigation of 43 high-school students. Data were collected through communication and travel diaries and in-depth interviews. Data from the Swedish National Communication Surveys, 1997–2001, cast light on the role of various ICT-based activities among young people in general. Results show that young people spend one and a half hours per day using computers, half of this time being spent on line. Young men and people with broadband access spend more time using computers than other groups do. Our indepth study revealed various types of users. The Internet is mainly used to communicate with people one already knows in real life and to reinforce existing contact patterns. Contacts are both geographically far-flung and very local, thus intensifying “glocal” patterns of communication. Virtual mobility and ICT-based strategies of behaviour complement, rather than replace, physical mobility and travel-based activities. ICT-based activities displace other in-home activities, such as watching television. A main conclusion is that virtual mobility has only minor impacts on the geographical locations of activities and thus on urban social and spatial structure in general

Virtual mobility and processes of displacement : Young people’s changing use of ICT, time, and place

Since the early 1990s an entirely new activity has entered the daily life of many households -the use of computers for on-line and off-line activities. It is anticipated that the resulting increased virtual mobility will have far-reaching consequences in terms of where, when, and how people use time and place for various activities. This paper explores the processes of “privatisation ” and “displacement”. By privatisation we refer to a process by which people withdraw from community, becoming more alone and socially isolated at home, with fewer face-to-face contacts. This denotes a broader question as to which activities -in-home or out-of-home -are displaced when information and communication technology (ICT) enters the time budgets of people. Data from extensive surveys and in-depth studies are used. A longitudinal study of the ICT use of young people in Sweden analysed one-week time-use diaries and in-depth interviews to yield detailed insights into ongoing trends. Data from the Swedish National Communication Surveys, 1997-2001, were used to cast light on general tendencies concerning the role of ICT in everyday life. Results show that heavy ICT users spend more time alone at home and less time socialising face-to-face. They use other kinds of media to the same extent as other groups do. However, a longitudinal analysis reveals that it is mainly time spent watching TV and on other home-based media activities that is displaced when people spend more time using ICT. Furthermore, ICT use adapts to the amount of free time available, rather than being directly determined by access to computers and the Internet.Depuis le début des années 1990 une activité entièrement nouvelle a modifié la vie quotidienne de beaucoup de ménages -l'utilisation des ordinateurs pour des activités en ligne et off-line. On prévoit que la mobilité virtuelle aura des conséquences de grande envergure en termes de gestion du temps des individus. Cet article explore les processus de la “privatisation” et du “déplacement”. Par privatisation nous nous référons à un processus par lequel les gens se retirent de la communauté, dans leur maison, avec peu de contacts en tête à tête. Finalement, la question est de savoir comment les individus qu ’ils soient “dans la maison ” ou “en dehors de la maison ” consacrent à la donnée TIC dans leur budget-temps. Les données proviennent de différentes études. Une étude longitudinale sur l'utilisation des TIC par des jeunes en Suède, sur la base d’une analyse d'une semaine temps est d’abord utilisée. Ensuite, ce sont des données issues des enquêtes nationales suédoises de communication, entre 1997 et 2001, qui ont été convoquées pour éclairer des tendances générales sur le rôle des TIC dans la vie quotidienne. Les résultats prouvent que le niveau de socialisation des gros utilisateurs des TIC est plus faible que l’usager normal. Toutefois, l'analyse indique que cet usage des TIC se fait principalement au détriment de la télévision ou d’autres types de médias présents dans le foyer. En outre, les usages des TIC sont dépendants de la quantité de temps libre disponible, plutôt que de la capacité à l'accès aux ordinateurs et à l'Internet.Thulin Eva, Vilhelmson Bertil. Virtual mobility and processes of displacement : Young people’s changing use of ICT, time, and place. In: NETCOM : Réseaux, communication et territoires / Networks and Communication Studies, vol. 20 n°1-2, november 2006. The role of place in the information age: I.T. use and knowledge creation. pp. 27-40