| 1. |
- Björn, Lars Olof, et al.
(författare)
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Växtvärldens uppkomst och utveckling
- 2020
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Bok (populärvet., debatt m.m.)abstract
- Tre forskare med olika specialinriktningar skildrar hur växternas förfäder för länge sedan uppstod genom att bakterier och andra enkla mikroskopiska varelser slog sig samman till en mer komplicerad organism. Från ett liv i vatten tog föregångarna till dagens växter steget upp på land. De förändrade vår planet på många sätt, och gjorde det möjligt för oss djur och människor att leva här. Växterna på många av de spår som evolutionen ledde in på har för länge sedan tagit dött ut. Andra utvecklingsspår, som under tidigare epoker dominerat växtlivet på vår planet har reducerats till något enda släkte eller en enda art. Ett utvecklingsspår har lett till den flora som nu helt dominerar jorden. Boken ger exempel på några särskilt intressanta nutida växter, och avsluts med en blick mot framtiden och vårt eget ansvar för den.
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| 2. |
- Christianson, Helena C, et al.
(författare)
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Tumor antigen glycosaminoglycan modification regulates antibody-drug conjugate delivery and cytotoxicity
- 2017
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Ingår i: Oncotarget. - : IMPACT JOURNALS LLC. - 1949-2553. ; 8:40, s. 66960-66974
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Tidskriftsartikel (refereegranskat)abstract
- Aggressive cancers are characterized by hypoxia, which is a key driver of tumor development and treatment resistance. Proteins specifically expressed in the hypoxic tumor microenvironment thus represent interesting candidates for targeted drug delivery strategies. Carbonic anhydrase (CAIX) has been identified as an attractive treatment target as it is highly hypoxia specific and expressed at the cell-surface to promote cancer cell aggressiveness. Here, we find that cancer cell internalization of CAIX is negatively regulated by post-translational modification with chondroitin or heparan sulfate glycosaminoglycan chains. We show that perturbed glycosaminoglycan modification results in increased CAIX endocytosis. We hypothesized that perturbation of CAIX glycosaminoglycan conjugation may provide opportunities for enhanced drug delivery to hypoxic tumor cells. In support of this concept, pharmacological inhibition of glycosaminoglycan biosynthesis with xylosides significantly potentiated the internalization and cytotoxic activity of an antibody-drug conjugate (ADC) targeted at CAIX. Moreover, cells expressing glycosaminoglycan-deficient CAIX were significantly more sensitive to ADC treatment as compared with cells expressing wild-type CAIX. We find that inhibition of CAIX endocytosis is associated with an increased localization of glycosaminoglycan-conjugated CAIX in membrane lipid raft domains stabilized by caveolin-1 clusters. The association of CAIX with caveolin-1 was partially attenuated by acidosis, i.e. another important feature of malignant tumors. Accordingly, we found increased internalization of CAIX at acidic conditions. These findings provide first evidence that intracellular drug delivery at pathophysiological conditions of malignant tumors can be attenuated by tumor antigen glycosaminoglycan modification, which is of conceptual importance in the future development of targeted cancer treatments.
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| 3. |
- Nonomura, Arthur M., et al.
(författare)
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The carbon reactions of photosynthesis : role of lectins and glycoregulation
- 2020
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Ingår i: Photosynthetica (Praha). - Prague : Institute of Experimental Botany of the Academy of Sciences of the Czech Republic. - 0300-3604 .- 1573-9058. ; 58:5, s. 1090-1097
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Forskningsöversikt (refereegranskat)abstract
- Modulation of glycoregulation in agriculture is reviewed here with emphasis on the elucidation of previously unknown pathways involving vacuolar lectins as well as a bypass of lectins that direct free sugars toward productivity. The reversible binding sequences of the endogenous lectin cycle are compared to an induced lectin bypass, as follows. (1) In the cycle, carbohydrate ligands, with similar binding specificities that compete for binding sites on lectins, are involved in the natural cycle of sugar exchanges. (2) For the bypass, tightly bound ligands that occupy lectins prevent free sugars from binding, making them available for productivity. This bypass is induced by methyl-α-D-mannopyranoside, a biochemical plant growth regulator for photosynthesis. Integration of this novel technology, with structural elements crucial for ligand binding by the lectins and with nitrogen assimilation, provides the basis for successful modulation of glycoregulation in crops for enhancement of quality and quantity.
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| 4. |
- Tikhonov, K., et al.
(författare)
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Quantification of bound bicarbonate in photosystem II
- 2018
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Ingår i: Photosynthetica (Praha). - : Institute of Experimental Botany. - 0300-3604 .- 1573-9058. ; 56:1, s. 210-216
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we presented a new approach for quantification of bicarbonate (HCO3-) molecules bound to PSII. Our method, which is based on a combination of membrane-inlet mass spectrometry (MIMS) and O-18-labelling, excludes the possibility of "non-accounted" HCO3- by avoiding (1) the employment of formate for removal of HCO3- from PSII, and (2) the extremely low concentrations of HCO3-/CO2 during online MIMS measurements. By equilibration of PSII sample to ambient CO2 concentration of dissolved CO2/HCO3-, the method ensures that all physiological binding sites are saturated before analysis. With this approach, we determined that in spinach PSII membrane fragments 1.1 +/- 0.1 HCO3- are bound per PSII reaction center, while none was bound to isolated PsbO protein. Our present results confirmed that PSII binds one HCO3- molecule as ligand to the non-heme iron of PSII, while unbound HCO3- optimizes the water-splitting reactions by acting as a mobile proton shuttle.
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