| 1. |
- Andersson, Inger
(författare)
-
Catalysis and regulation in Rubisco.
- 2008
-
Ingår i: Journal of Experimental Botany. - : Oxford University Press (OUP). - 0022-0957 .- 1460-2431. ; 59:7, s. 1555-1568
-
Tidskriftsartikel (refereegranskat)abstract
- Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyses the incorporation of inorganic CO(2) into the organic molecules of life. Rubisco is extremely inefficient as a catalyst and its carboxylase activity is compromised by numerous side-reactions including oxygenation of its sugar phosphate substrate by atmospheric O(2). The reduction in the catalytic efficiency as a result of these processes has implications for crop yield, nitrogen and water usage, and for the global carbon cycle. Several aspects of Rubisco including its complex biosynthesis and multi-step catalytic reaction are subject to tight control involving light, cellular metabolites, and molecular chaperones. Numerous high-resolution crystal structures of different forms of Rubisco are now available, including structures of mutant enzymes. These provide a molecular framework for the understanding of these processes at the molecular level.
|
|
| 2. |
- Andersson, Inger, 1964, et al.
(författare)
-
Health-related quality of life in patients undergoing allogeneic stem cell
- 2009
-
Ingår i: Cancer Nursing. - 0162-220X. ; 32:4
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this prospective study was to describe health-related quality of life (HRQOL) in patients during the first year after stem cell transplantation (SCT) who were undergoing reduced intensive conditioning (RIC) compared with patients undergoing myeloablative conditioning (MAC). Fifty-seven patients (25 for MAC and 32 for RIC) were enrolled in the study. HRQOL was assessed at 6 occasions during the first year after SCT using European Organization for Research and Treatment of Cancer Quality of Life Questionnaire and the 19-item treatment-specific module High-Dose Chemotherapy. Both groups reported most symptoms and worst functioning 1 month after SCT, but there were substantial differences. The MAC group deteriorated considerably in 20 symptom scales compared with 8 in the RIC group (score differences <10; P values ranged from .001 to .05). Dry mouth, sore mouth, appetite loss, and change of taste were among the most frequent symptoms in both groups. Thereafter, the functioning improved and the symptom scores decreased and returned to baseline in both groups, except dry mouth, which remained a worse problem for the MAC group. Overall, the RIC group regained health and QOL faster than the MAC group did. However, there were no significant differences in global QOL between the groups 1 year after SCT.
|
|
| 3. |
- Andersson, Inger, 1964, et al.
(författare)
-
Health related quality of life in stem cell transplantation: clinical and psychometric validation of the questionnaire module, High Dose Chemotherapy (HDC-19).
- 2008
-
Ingår i: Acta oncologica (Stockholm, Sweden). - : Informa UK Limited. - 0284-186X .- 1651-226X. ; 47:2, s. 275-85
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to assess the psychometric properties of the HDC-19, a module questionnaire for assessing symptoms and problems of patients undergoing stem cell transplantation (SCT) following high-dose chemotherapy (HDC). It consists of 19 questions and was developed for use in conjunction with EORTC QLQ-C30. Psychometric evaluations were performed according to guidelines recommended by the EORTC. The principal component analyses suggested that nine of the HDC-19 items could be reduced to four components (sexual functioning, future health perspectives, skin irritations and joint/muscle pain). Multitrait scaling analysis showed that most item-scale correlation coefficients met the standards of convergent (>0.40) and discriminant validity. Test-retest reliability coefficients between assessments at inclusion and admission were high, indicating that perceived health status remained virtually unchanged during this period. As expected, correlations between admission and one month after transplantation were considerably lower. The internal consistency of the multi-item scales was also satisfactory, (Cronbach's alpha 0.59-0.87). Overall, the known-groups comparisons showed smaller differences between designated groups than expected. As expected, changes in the HDC-19 mirrored changes in QLQ-C30 'global quality of life'. These results lend support to the validity of the HDC-19 as a supplementary questionnaire for assessing specific health-related quality of life (HRQOL) issues relevant for SCT patients.
|
|
| 4. |
- Andersson, Inger, et al.
(författare)
-
Structure and function of Rubisco
- 2008
-
Ingår i: Plant physiology and biochemistry (Paris). - : Elsevier BV. - 0981-9428 .- 1873-2690. ; 46:3, s. 275-291
-
Tidskriftsartikel (refereegranskat)abstract
- Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the major enzyme assimilating CO2 into the biosphere. At the same time Rubisco is an extremely inefficient catalyst and its carboxylase activity is compromised by an opposing oxygenase activity involving atmospheric O2. The shortcomings of Rubisco have implications for crop yield, nitrogen and water usage, and for the global carbon cycle. Numerous high-resolution crystal structures of different forms of Rubisco are now available, including structures of mutant enzymes. This review uses the information provided in these structures in a structure-based sequence alignment and discusses Rubisco function in the context of structural variations at all levels – amino acid sequence, fold, tertiary and quaternary structure – with an evolutionary perspective and an emphasis on the structural features of the enzyme that may determine its function as a carboxylase.
|
|
| 5. |
- Cicero, Giancarlo, et al.
(författare)
-
Study of the oxidative half-reaction catalyzed by a non-heme ferrous catalytic center by means of structural and computational methodologies
- 2007
-
Ingår i: International Journal of Quantum Chemistry. - : Wiley. - 0020-7608 .- 1097-461X. ; 107:6, s. 1514-1522
-
Tidskriftsartikel (refereegranskat)abstract
- Deacetoxycephalosporin C synthase (DAOCS) is a mononuclear ferrous enzyme that catalyzes the expansion of the five-membered thiazolidine ring of the penicillin nucleus into the six-membered dihydrothiazine ring of the cephalosporins. In the first half-reaction with dioxygen and 2-oxoglutarate, a reactive iron-oxygen species is produced that can subsequently react with the penicillin substrate to yield the cephalosporin. We describe quantum mechanical calculations of the first part of the reaction based on the high-resolution structures of the active site of DAOCS and its complexes with ligands. These studies are aimed at understanding how the reactive species can be produced and contained in the active site of the enzyme. The results demonstrate the priming of the active site by the co-substrate for oxygen binding and hint to the presence of a stable iron-peroxo intermediate in equilibrium with a more reactive ferryl species and the formation of CO2 as a leaving group by decarboxylation of 2-oxoglutarate. A conclusion from these studies is that substitution of CO2 by the penicillin substrate triggers the oxidation reaction in a booby-trap-like mechanism.
|
|
| 6. |
- García-Murria, María-Jesús, et al.
(författare)
-
Structural and functional consequences of the replacement of proximal residues Cys(172) and Cys(192) in the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase from Chlamydomonas reinhardtii.
- 2008
-
Ingår i: Biochemical Journal. - 0264-6021 .- 1470-8728. ; 411:2, s. 241-247
-
Tidskriftsartikel (refereegranskat)abstract
- Proximal Cys(172) and Cys(192) in the large subunit of the photosynthetic enzyme Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase; EC 4.1.1.39) are evolutionarily conserved among cyanobacteria, algae and higher plants. Mutation of Cys(172) has been shown to affect the redox properties of Rubisco in vitro and to delay the degradation of the enzyme in vivo under stress conditions. Here, we report the effect of the replacement of Cys(172) and Cys(192) by serine on the catalytic properties, thermostability and three-dimensional structure of Chlamydomonas reinhardtii Rubisco. The most striking effect of the C172S substitution was an 11% increase in the specificity factor when compared with the wild-type enzyme. The specificity factor of C192S Rubisco was not altered. The V(c) (V(max) for carboxylation) was similar to that of wild-type Rubisco in the case of the C172S enzyme, but approx. 30% lower for the C192S Rubisco. In contrast, the K(m) for CO(2) and O(2) was similar for C192S and wild-type enzymes, but distinctly higher (approximately double) for the C172S enzyme. C172S Rubisco showed a critical denaturation temperature approx. 2 degrees C lower than wild-type Rubisco and a distinctly higher denaturation rate at 55 degrees C, whereas C192S Rubisco was only slightly more sensitive to temperature denaturation than the wild-type enzyme. X-ray crystal structures reveal that the C172S mutation causes a shift of the main-chain backbone atoms of beta-strand 1 of the alpha/beta-barrel affecting a number of amino acid side chains. This may cause the exceptional catalytic features of C172S. In contrast, the C192S mutation does not produce similar structural perturbations.
|
|
| 7. |
- Karkehabadi, Saeid, et al.
(författare)
-
Structural analysis of altered large-subunit loop-6/carboxy-terminus interactions that influence catalytic efficiency and CO2/O2 specificity of ribulose-1,5-bisphosphate carboxylase/oxygenase.
- 2007
-
Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 46:39, s. 11080-11089
-
Tidskriftsartikel (refereegranskat)abstract
- The loop between alpha-helix 6 and beta-strand 6 in the alpha/beta-barrel of ribulose-1,5-bisphosphate carboxylase/oxygenase plays a key role in discriminating between CO2 and O2. Genetic screening in Chlamydomonas reinhardtii previously identified a loop-6 V331A substitution that decreases carboxylation and CO2/O2 specificity. Revertant selection identified T342I and G344S substitutions that restore photosynthetic growth by increasing carboxylation and specificity of the V331A enzyme. In numerous X-ray crystal structures, loop 6 is closed or open depending on the activation state of the enzyme and the presence or absence of ligands. The carboxy terminus folds over loop 6 in the closed state. To study the molecular basis for catalysis, directed mutagenesis and chloroplast transformation were used to create T342I and G344S substitutions alone. X-ray crystal structures were then solved for the V331A, V331A/T342I, T342I, and V331A/G344S enzymes, as well as for a D473E enzyme created to assess the role of the carboxy terminus in loop-6 closure. V331A disturbs a hydrophobic pocket, abolishing several van der Waals interactions. These changes are complemented by T342I and G344S, both of which alone cause decreases in CO2/O2 specificity. In the V331A/T342I revertant enzyme, Arg339 main-chain atoms are displaced. In V331A/G344S, alpha-helix 6 is shifted. D473E causes disorder of the carboxy terminus, but loop 6 remains closed. Interactions between a transition-state analogue and several residues are altered in the mutant enzymes. However, active-site Lys334 at the apex of loop 6 has a normal conformation. A variety of subtle interactions must be responsible for catalytic efficiency and CO2/O2 specificity.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Lundberg, Gun, 1950-
(författare)
-
Teachers in action : att förändra och utveckla undervisning och lärande i engelska i de tidigare skolåren
- 2007
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sweden has for many years suffered from a shortage of teachers appropriately trained to teach English to young learners. In 1987 The Swedish National Agency for Higher Education decided that English should no longer be a compulsory subject within primary teacher training, instead it was offered as an optional subject within the primary teacher training programmes This policy decision had dire consequences and ultimately led to the current position which sees a mere 30 % of trainee Teachers opting for the English language pathway.Although consensus has been achieved in Europe and beyond relating to the advantages of teaching modern languages at an early age there are significant variations between regions and schools relating to the introduction of English in primary schools and implementation of the national syllabus for English is still undeveloped in many schools. The syllabus for English and the learning objectives to be attained by the end of Year 5 in school (11-year-olds) are very wide. These wide goals can appear very attractive to a qualified teacher, educated in appropriate methodology and having access to plenty of authentic target language teaching material, but for an unqualified teacher these national goals are not easily transferred into practice. This is probably the main reason why the use of textbooks and workbooks seem to be regarded as the most appropriate pedagogy instead of a more communicative approach to teaching and learning of English.This contextual background was the starting point for the design of an in-service course for primary teachers who are unqualified to teach English to young learners but who are obliged to do so as the Swedish primary school system operates mostly on the principle of a generic class teacher who delivers all curriculum areas. The shortage of teachers appropriately trained to teach English to young learners and the lack of parity for English as a subject in the early school years brought about the call for effective in-service training with a built-in capacity for challenging traditions and the development of sustainable change and improvement towards a more communicative approach of teaching and learning in the language classroom.The in-service course was designed as a part-time, distance course of 15 ECTS over a period of 20 weeks, the model being for teachers to divide their delivery and study time on a 50/50 basis, a blend of theory and practice. The aims were to emphasise research-based teaching and strive for a goal of better applications into practise of the centralised syllabus based on the European Framework of References, CEFR, and the communicative approach to teaching and learning of languages. A further aim was todevelop more confidence and autonomy in the teachers. An action research module was integrated into the course as it was considered to have the capacity to improve educational practice, promote professional development and enhance classroom performance. Action research is also understood to have a potential for long-term change and commitment through encouraging professionals to reflect critically on their often taken-for-granted practices where uncontested beliefs and values are held by staff members.The results of the action research projects reveal that whilst it is difficult to bring about change in school cultures which have strongly embedded traditional teaching habits there is also an accompanying body of evidence demonstrating improvement in teaching and learning pedagogy for young learners in the north of Sweden. The action research projects have been organised into five themes: (1)An Early start, (2)Target language use,(3) Motivation, (4) Language methodology and didactics and (5)Documentation and progression.A summary of the analysis of 123 action research project reports indicates that teachers seem to be convinced that children as young as 6-7 can benefit from early language learning if the circumstances are right with age-appropriate methodology and a secure classroom climate. Teachers have initiated a more consistent target language approach in their classrooms and the pupils have actively engaged by starting to use the target language more frequently during lessons and even beyond their formal sessions.Both teachers and pupils alike have begun to articulate that English is fun, stimulating and enjoyable. The use of language strategies such as guessing competence and strategic competence has increased together with continuous discussions about the processes of language learning and addressing of didactic core questions revolving around why, how and what. The introduction of small steps of scaffolding technique for learner autonomy has resulted in pupils generating lots of ideas for English to bring the subject alive and English is no longer an isolated stand alone subject instead it is more successfully merged holistically into the generic skill and competence base for Early Learning provision. All kinds of inventive documentation and evaluation ideas, language portfolios and recordings of oral skills have become useful tools for assessing language progress and for assurance of continuity and progression in language learning.Teaching is an increasingly challenging process requiring sophisticated skills, competencies and qualities. Teachers therefore are playing pivotal roles in the drive towards improving language learning amongst our pupils and the application of action research seems to have assisted their practice. With action research as a tool teachers are able to develop their professional learning through systematic investigation rather than by reproduction of disconnected teaching tips. Through action research, teachers will begin to understand what is really happening in their classrooms, why it is happening and how teaching and learning can be systematically improved. This study illustrates how 123 action research projects, carried out by the teachers in their own practices, have encouraged self directed professional learning, increased confidence, competence and pupil engagement.
|
|
