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- Santilli, Andrea, et al.
(författare)
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Bioderived, chiral and stable 1-dimensional light-responsive nanostructures : Interconversion between tubules and twisted ribbons
- 2022
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797. ; 623, s. 723-734
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Tidskriftsartikel (refereegranskat)abstract
- HYPOTHESIS: Self-assembling molecular structures responding to light stimulus are appealing for applications as sensing and drug delivery. Supramolecular nanotubes have a relevant potential in nanotechnology as they can be used to encapsulate different loads like drugs, biological macromolecules, and nanomaterials. In addition, they are suitable elements for novel supracolloidal materials. Structural responses of supramolecular nanotubes to non-invasive stimuli are very much desired to enable controlled release of the encapsulated guests and to provide these recently developed new materials with an external trigger. Here, we describe the formation of well-defined, single wall tubules that interconvert into twisted ribbons upon UV-light exposure in aqueous environment. The structures are provided by self-assembly of an azobenzene substituted cholic acid, a biological surfactant belonging to the family of bile acids. The azobenzene group allows for the light responsiveness of the molecular packing. Concurrently the steroidal moieties assure both chiral features and extensive hydrophobic interactions for time and temperature resistant aggregates.EXPERIMENTS: The molecular packing interconversion was followed by circular dichroism. Microscopy, small angle X-ray scattering and light scattering measurements demonstrated the drastic morphological variation upon irradiation. A model of the molecular arrangement within the tubular walls was suggested based on the circular dichroism spectra simulation.FINDINGS: Innovatively, the molecular design reported in our work allows for encoding in the same light responsive system multiple desirable features (e.g. bio-origin, temperature resistance and chirality of the aggregates). Such combination of properties, never reported before for a single molecule, might be relevant for the realization of robust, stimuli-responsive bio-vectors.
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| 2. |
- Chiesa, Nicoletta, et al.
(författare)
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The KCNQ1OT1 imprinting control region and non-coding RNA : new properties derived from the study of Beckwith-Wiedemann syndrome and Silver-Russell syndrome cases
- 2012
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 21:1, s. 10-25
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Tidskriftsartikel (refereegranskat)abstract
- A cluster of imprinted genes at chromosome 11p15.5 is associated with the growth disorders, Silver-Russell syndrome (SRS) and Beckwith-Wiedemann syndrome (BWS). The cluster is divided into two domains with independent imprinting control regions (ICRs). We describe two maternal 11p15.5 microduplications with contrasting phenotypes. The first is an inverted and in cis duplication of the entire 11p15.5 cluster associated with the maintenance of genomic imprinting and with the SRS phenotype. The second is a 160 kb duplication also inverted and in cis, but resulting in the imprinting alteration of the centromeric domain. It includes the centromeric ICR (ICR2) and the most 5' 20 kb of the non-coding KCNQ1OT1 gene. Its maternal transmission is associated with ICR2 hypomethylation and the BWS phenotype. By excluding epigenetic mosaicism, cell clones analysis indicated that the two closely located ICR2 sequences resulting from the 160 kb duplication carried discordant DNA methylation on the maternal chromosome and supported the hypothesis that the ICR2 sequence is not sufficient for establishing imprinted methylation and some other property, possibly orientation-dependent, is needed. Furthermore, the 1.2 Mb duplication demonstrated that all features are present for correct imprinting at ICR2 when this is duplicated and inverted within the entire cluster. In the individuals maternally inheriting the 160 kb duplication, ICR2 hypomethylation led to the expression of a truncated KCNQ1OT1 transcript and to down-regulation of CDKN1C. We demonstrated by chromatin RNA immunopurification that the KCNQ1OT1 RNA interacts with chromatin through its most 5' 20 kb sequence, providing a mechanism likely mediating the silencing activity of this long non-coding RNA.
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