| 1. |
- van der Oost, John, et al.
(författare)
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Bacillus subtilis cytochrome oxidase mutants: biochemical analysis and genetic evidence for two aa3-type oxidases
- 1991
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Ingår i: Molecular Microbiology. - : Wiley. - 1365-2958 .- 0950-382X. ; 5:8, s. 2063-2072
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Tidskriftsartikel (refereegranskat)abstract
- The ctaBCDEF genes coding for cytochrome c oxidase were found to reside adjacent to a regulatory gene ctaA at 127-degrees on the Bacillus subtilis chromosome. The structural genes for subunits I and II, ctaD and ctaC, were deleted by gene-replacement using a phleomycin-resistance marker. The mutant was unable to oxidize N,N,N',N'-tetramethyl-p-phenylenediamine and oxidized cytochrome c at a significantly lower rate. Absorption spectra of the mutant and wild-type membranes confirmed the presence of two haem A-containing enzymes in B. subtilis. Another mutant, with a spontaneous deletion upstream from ctaC, was found to express neither of these enzymes. Radioactive haem-labelling was used to identify subunit 11, which contains a haem C, and cytochrome c-550 among the membrane-bound c-type cytochromes of B. subtilis.
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| 2. |
- Axelson, H, et al.
(författare)
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A new variant 15; 16 translocation in mouse plasmacytoma leads to the juxtaposition of c-myc and immunoglobulin lambda
- 1991
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Ingår i: Oncogene. - 0950-9232. ; 6:12, s. 70-2263
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Tidskriftsartikel (refereegranskat)abstract
- Mouse plasmacytomas (MPCs) induced by pristane oil, or by a combination of pristane oil and Abelson virus, carry one of two chromosomal translocations. The typical 12; 15 translocation leads to the juxtaposition of c-myc and immunoglobulin heavy-chain sequences, whereas the 6; 15 translocation links the kappa light-chain locus with the pvt-1 (plasmacytoma variant translocation) locus, located at least 75kb 3' of c-myc [Cory, S., Graham, M., Webb, E., Corcoran, L. & Adams, J. (1985). EMBO J., 4, 675-681]. Unlike the human Burkitt's lymphoma-associated translocation, the lambda/myc juxtaposed variant translocation has not been found previously in MPCs. Using unconventional MPC induction systems in which the tumor precursor cell was induced to proliferate in a secondary host, we have recently identified a 15; 16 translocation in six of the derived MPCs [Wiener, F., Silva, S., Sugiyama, H., Babonits, M. & Klein, G. (1990). Genes Chromosomes Cancer, 2, 36-43]. Chromosome 16 harbors the lambda light-chain gene. To explore whether the 15; 16 translocation represents the lambda/myc juxtaposition, we have mapped the breakpoints on chromosomes 15 and 16 by pulsed-field gel electrophoresis (PFGE). The pvt-1 region was mapped to approximately 220 kb 3' of c-myc. The breakpoint on chromosome 15 in ABPC-Ch-163-10, one of the six 15; 16 translocation-carrying MPCs, was situated approximately 80 kb 3' of c-myc and 140 kb 5' of pvt-1b, the major breakpoint cluster region of the previously analysed 6; 15 variant MPCs. The breakpoint on chromosome 16 was found to cut between the V1 and C3 regions of the lambda locus. Co-migration experiments showed that the C3 and the myc gene were juxtaposed head to tail on the 15; 16 translocation chromosome. On the reciprocal product V1 was juxtaposed to pvt-1.
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| 3. |
- Bengtsson, Henrik, et al.
(författare)
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A population based screening of abdominal aortic aneurysms (AAA)
- 1991
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Ingår i: European Journal of Vascular Surgery. - 0950-821X. ; 5:1, s. 53-57
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Tidskriftsartikel (refereegranskat)abstract
- The prevalence of abdominal aortic aneurysm (AAA) in a defined population of elderly men and its correlation to some risk factors were studied in the population cohort "men born in 1914 from Malmo". A total of 499 were invited to attend and 375 (75%) did so. The aorta could be visualised with ultrasound in 364 patients, 39 (10.7%) of whom had aneurysmal changes. The presence of an AAA was related to the findings at a general health examination undertaken 5 years previously. Tobacco and alcohol consumption, impaired lung function and a history of angina pectoris were related to the presence of an AAA. No relationship was found between an AAA and hypertension, hyperlipidaemia or hyperglycaemia. A decreased tissue elasticity as a common denominator for the lung function impairment and development of AAA is discussed.
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| 4. |
- Hughes, Diarmaid, 1956-
(författare)
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Error-prone EF-Tu reduces in vivo enzyme activity and cellular growth rate
- 1991
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Ingår i: Molecular Microbiology. - 0950-382X .- 1365-2958. ; 5:3, s. 623-630
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in Salmonella typhimurium encoding error-prone EF-Tu (tufA8, tufB103) enhance translational error levels and also cause a reduced growth rate. The relative changes in error level and growth rate are inversely related and dependent on the status of the two tuf genes. Possible causes of the reduced growth rate were investigated. Several important parameters with the potential to alter growth rate (the EF-Tu-ribosome interaction, the in vivo elongation rate and the processivity of translation), are all relatively unaffected by the tuf mutations. The small reduction in processivity observed in some strains is not quantitatively related to the growth rate reduction. Instead, the error-enhancing mutations are associated with a large reduction in the specific activity of a test protein, β-galactosidase, suggesting by inference that the reduced growth rate is a consequence of the synthesis of error-containing proteins.
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| 5. |
- Lundgren, Birgit, et al.
(författare)
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Extruded wheat flour: Flavour and texture-comparison of evaluations by two laboratories
- 1991
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Ingår i: Food Quality and Preference. - 0950-3293 .- 1873-6343. ; 3:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Intensities of flavour and texture attributes of 23 extruded wheat flour samples were evaluated by two laboratory panels in Sweden and in the UK. For most attributes good agreement between the two panels was obtained. Discrepancies were considered to be caused by inadequate definition of the terms. © 1992.
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| 6. |
- Andersson, Hanna, 1991-, et al.
(författare)
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Anchoring effect in judgments of objective fact and subjective preference
- 2021
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Ingår i: Food Quality and Preference. - : Elsevier. - 0950-3293 .- 1873-6343. ; 88
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Tidskriftsartikel (refereegranskat)abstract
- The way by which various sources of external information interact in their effects on judgment is rarely investigated. Here, we report two experiments that examine how two sources of external information—an anchor (a reference price) and an eco-label—influence judgments of an objective fact (product price) and a subjective preference (willingness-to-pay for the product). Participants’ price judgments were drawn in the direction of the anchor point, whereas the eco-label resulted in higher judgments of objective fact (Experiment 1) but did not influence subjective preference (Experiment 2). Interestingly, the eco-label seemed to strengthen the effect of the high anchor in judgments of objective fact. Further, participants with higher environmental concern answered a higher price on the subjective preference questions when they received a high anchor, as well as a lower price when they received a low anchor in comparison to the low environmental concern group. This study demonstrates that various external information sources can strengthen each other’s effects on consumer belief about products, while the effects are weaker for consumers’ preferences. The implications of the results for decision making are discussed.
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| 7. |
- Podraza-Farhanieh, Agnieszka, 1991, et al.
(författare)
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A proinsulin-dependent interaction between ENPL-1 and ASNA-1 in neurons is required to maintain insulin secretion in C. elegans.
- 2023
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Ingår i: Development (Cambridge, England). - : The Company of Biologists. - 1477-9129 .- 0950-1991. ; 150:6
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Tidskriftsartikel (refereegranskat)abstract
- Neuropeptides, including insulin, are important regulators of physiological functions of the organisms. Trafficking through the Golgi is crucial for the regulation of secretion of insulin-like peptides. ASNA-1 (TRC40) and ENPL-1 (GRP94) are conserved insulin secretion regulators in Caenorhabditis elegans (and mammals), and mouse Grp94 mutants display type 2 diabetes. ENPL-1/GRP94 binds proinsulin and regulates proinsulin levels in C. elegans and mammalian cells. Here, we have found that ASNA-1 and ENPL-1 cooperate to regulate insulin secretion in worms via a physical interaction that is independent of the insulin-binding site of ENPL-1. The interaction occurs in DAF-28/insulin-expressing neurons and is sensitive to changes in DAF-28 pro-peptide levels. Consistently, ASNA-1 acted in neurons to promote DAF-28/insulin secretion. The chaperone form of ASNA-1 was likely the interaction partner of ENPL-1. Loss of asna-1 disrupted Golgi trafficking pathways. ASNA-1 localization to the Golgi was affected in enpl-1 mutants and ENPL-1 overexpression partially bypassed the ASNA-1 requirement. Taken together, we find a functional interaction between ENPL-1 and ASNA-1 that is necessary to maintain proper insulin secretion in C. elegans and provides insights into how their loss might cause diabetes in mammals.
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| 8. |
- Wang, Y. J., et al.
(författare)
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Cyclic AMP in oocytes controls meiotic prophase I and primordial folliculogenesis in the perinatal mouse ovary
- 2015
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Ingår i: Development. - : The Company of Biologists. - 0950-1991 .- 1477-9129. ; 142:2, s. 343-351
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Tidskriftsartikel (refereegranskat)abstract
- In mammalian ovaries, a fixed population of primordial follicles forms during the perinatal stage and the oocytes contained within are arrested at the dictyate stage of meiotic prophase I. In the current study, we provide evidence that the level of cyclic AMP ( cAMP) in oocytes regulates oocyte meiotic prophase I and primordial folliculogenesis in the perinatal mouse ovary. Our results show that the early meiotic development of oocytes is closely correlated with increased levels of intra-oocyte cAMP. Inhibiting cAMP synthesis in fetal ovaries delayed oocyte meiotic progression and inhibited the disassembly and degradation of synaptonemal complex protein 1. In addition, inhibiting cAMP synthesis in in vitro cultured fetal ovaries prevented primordial follicle formation. Finally, using an in situ oocyte chromosome analysis approach, we found that the dictyate arrest of oocytes is essential for primordial follicle formation under physiological conditions. Taken together, these results suggest a role for cAMP in early meiotic development and primordial follicle formation in the mouse ovary.
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| 9. |
- Wolfstetter, Georg, et al.
(författare)
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Characterization of Drosophila Nidogen/entactin reveals roles in basement membrane stability, barrier function and nervous system patterning
- 2019
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Ingår i: Development. - : The Company of Biologists. - 0950-1991 .- 1477-9129. ; 146:2
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Tidskriftsartikel (refereegranskat)abstract
- Basement membranes (BMs) are specialized layers of extracellular matrix (ECM) mainly composed of Laminin, type IV Collagen, Perlecan and Nidogen/entactin (NDG). Recent in vivo studies challenged the initially proposed role of NDG as a major ECM linker molecule by revealing dispensability for viability and BM formation. Here, we report the characterization of the single Ndg gene in Drosophila. Embryonic Ndg expression was primarily observed in mesodermal tissues and the chordotonal organs, whereas NDG protein localized to all BMs. Although loss of Laminin strongly affected BM localization of NDG, Ndg-null mutants exhibited no overt changes in the distribution of BM components. Although Drosophila Ndg mutants were viable, loss of NDGled to ultrastructural BM defects that compromised barrier function and stability in vivo. Moreover, loss of NDG impaired larval crawling behavior and reduced responses to vibrational stimuli. Further morphological analysis revealed accompanying defects in the larval peripheral nervous system, especially in the chordotonal organs and the neuromuscular junction (NMJ). Taken together, our analysis suggests that NDG is not essential for BM assembly but mediates BM stability and ECM-dependent neural plasticity during Drosophila development.
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| 10. |
- Galozy, Alexander, 1991-, et al.
(författare)
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Information-gathering in latent bandits
- 2023
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Ingår i: Knowledge-Based Systems. - Amsterdam : Elsevier. - 0950-7051 .- 1872-7409. ; 260
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Tidskriftsartikel (refereegranskat)abstract
- In the latent bandit problem, the learner has access to reward distributions and – for the non-stationary variant – transition models of the environment. The reward distributions are conditioned on the arm and unknown latent states. The goal is to use the reward history to identify the latent state, allowing for the optimal choice of arms in the future. The latent bandit setting lends itself to many practical applications, such as recommender and decision support systems, where rich data allows the offline estimation of environment models with online learning remaining a critical component. Previous solutions in this setting always choose the highest reward arm according to the agent’s beliefs about the state, not explicitly considering the value of information-gathering arms. Such information-gathering arms do not necessarily provide the highest reward, thus may never be chosen by an agent that chooses the highest reward arms at all times.In this paper, we present a method for information-gathering in latent bandits. Given particular reward structures and transition matrices, we show that choosing the best arm given the agent’s beliefs about the states incurs higher regret. Furthermore, we show that by choosing arms carefully, we obtain an improved estimation of the state distribution, and thus lower the cumulative regret through better arm choices in the future. Through theoretical analysis we show that the proposed method retains the sub-linear regret rate of previous methods while having much better problem dependent constants. We evaluate our method on both synthetic and real-world data sets, showing significant improvement in regret over state-of-the-art methods. © 2022 The Author(s).
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