8 research outputs found
Selective discrimination and classification of G-quadruplex structures with a host–guest sensing array
The secondary structures of nucleic acids have an important influence on their cellular functions but can be difficult to identify
and classify quickly. Here, we show that an arrayed suite of synthetic hosts and dyes is capable of fluorescence detection of
oligonucleotide secondary structures. Multivariate analysis of different fluorescence enhancements—generated using cationic
dyes that show affinity for both DNA G-quadruplexes and the synthetic hosts—enables discrimination between G-quadruplex
structures of identical length and highly similar topological types. Different G-quadruplexes that display the same folding
topology can also be easily differentiated by the number of G-quartets and sequence differences at the 3′ or 5′ ends. The array
is capable of both differentiation and classification of the G-quadruplex structures at the same time. This simple non-invasive
sensing method does not require the discovery and synthesis of specific G-quadruplex binding ligands, but employs a simple
multicomponent approach to ensure wide applicability
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Sensing of citrulline modifications in histone peptides by deep cavitand hosts
Arrayed cavitand:fluorophore sensor complexes can selectively sense small citrulline modifications at arginine residues on post-translationally modified peptides. The sensor can differentiate between different numbers of citrulline modifications, and a simple two-fluorophore, 6-component array can effect cross-reactive discrimination between single modifications in aqueous solution
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Selective recognition and discrimination of single isomeric changes in peptide strands with a host:guest sensing array
An indirect competitive binding mechanism can be exploited to allow a combination of cationic fluorophores and water-soluble synthetic receptors to selectively recognize and discriminate peptide strands containing a single isomeric residue in the backbone. Peptide isomerization occurs in long-lived proteins and has been linked with diseases such as Alzheimer's, cataracts and cancer, so isomers are valuable yet underexplored targets for selective recognition. Planar cationic fluorophores can selectively bind hydrophobic, Trp-containing peptide strands in solution, and when paired with receptors that provide a competitive host for the fluorophore, can form a differential sensing array that enables selective discrimination of peptide isomers. Residue variations such as D- and L-Asp, D- and L-isoAsp, D-Ser and D-Glu can all be recognized, simply by their effects on the folded structure of the flexible peptide. Molecular dynamics simulations were applied to determine the most favorable conformation of the peptide : fluorophore conjugate, indicating that favorable π-stacking with internal tryptophan residues in a folded binding pocket enables micromolar binding affinity
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Selective Molecular Recognition and Indicator Displacement Sensing of Neurotransmitters in Cellular Environments
Flexible, water-soluble hosts are capable of selective molecular recognition in cellular environments and can detect neurotransmitters such as choline in cells. Both cationic and anionic water-soluble self-folded deep cavitands can recognize suitable styrylpyridinium dyes in cellular interiors. The dyes selectively accumulate in nucleotide-rich regions of the cell nucleus and cytoplasm. The hosts bind the dyes and promote their relocation to the outer cell membrane: the lipophilic cavitands predominantly reside in membrane environments but are still capable of binding suitable targets in other cellular organelles. Incubating the cells with structurally similar biomarkers such as choline, cholamine, betaine, or butyrylcholine illustrates the selective recognition. Choline and butyrylcholine can be bound by the hosts, but minimal binding is seen with betaine or cholamine. Varying the dye allows control of the optical detection method, and both "turn-on" sensing and "turn-off" sensing are possible
Using Flipped Classroom Modules to Facilitate Higher Order Learning in Undergraduate Organic Chemistry
In an ongoing effort to incorporate active learning and
promote
higher order learning outcomes in undergraduate organic chemistry,
a hybrid (“flipped”) classroom structure has been used
to facilitate a series of collaborative activities in the first two
courses of the lower division organic chemistry sequence. An observational
study of seven classes over a five-year period reveals there is a
strong correlation between performance on the in-class activities
and performance on the final exam across all classes; however, a significant
number of students in these courses continue to struggle on both the
in-class activities and final exam. The Activity Engagement Survey
(AcES) was administered in the most recent course offering included
in this study, and these preliminary data suggest that students who
achieved lower scores on the in-class activities had lower levels
of emotional and behavioral/cognitive engagement and were less likely
to work in collaborative groups. In total, these findings suggest
that if students can be guided to engage more successfully with the
in-class activities, they are likely to be more successful in carrying
out the higher order learning required on the final exam. In addition
to the analyses of student performance and engagement in the in-class
activities, the implementation of the flipped classroom structure
and suggestions for how student engagement in higher order learning
might be improved in future iterations of the class are described
herein
Using Flipped Classroom Modules to Facilitate Higher Order Learning in Undergraduate Organic Chemistry
In an ongoing effort to incorporate active learning and
promote
higher order learning outcomes in undergraduate organic chemistry,
a hybrid (“flipped”) classroom structure has been used
to facilitate a series of collaborative activities in the first two
courses of the lower division organic chemistry sequence. An observational
study of seven classes over a five-year period reveals there is a
strong correlation between performance on the in-class activities
and performance on the final exam across all classes; however, a significant
number of students in these courses continue to struggle on both the
in-class activities and final exam. The Activity Engagement Survey
(AcES) was administered in the most recent course offering included
in this study, and these preliminary data suggest that students who
achieved lower scores on the in-class activities had lower levels
of emotional and behavioral/cognitive engagement and were less likely
to work in collaborative groups. In total, these findings suggest
that if students can be guided to engage more successfully with the
in-class activities, they are likely to be more successful in carrying
out the higher order learning required on the final exam. In addition
to the analyses of student performance and engagement in the in-class
activities, the implementation of the flipped classroom structure
and suggestions for how student engagement in higher order learning
might be improved in future iterations of the class are described
herein
Using Flipped Classroom Modules to Facilitate Higher Order Learning in Undergraduate Organic Chemistry
In an ongoing effort to incorporate active learning and
promote
higher order learning outcomes in undergraduate organic chemistry,
a hybrid (“flipped”) classroom structure has been used
to facilitate a series of collaborative activities in the first two
courses of the lower division organic chemistry sequence. An observational
study of seven classes over a five-year period reveals there is a
strong correlation between performance on the in-class activities
and performance on the final exam across all classes; however, a significant
number of students in these courses continue to struggle on both the
in-class activities and final exam. The Activity Engagement Survey
(AcES) was administered in the most recent course offering included
in this study, and these preliminary data suggest that students who
achieved lower scores on the in-class activities had lower levels
of emotional and behavioral/cognitive engagement and were less likely
to work in collaborative groups. In total, these findings suggest
that if students can be guided to engage more successfully with the
in-class activities, they are likely to be more successful in carrying
out the higher order learning required on the final exam. In addition
to the analyses of student performance and engagement in the in-class
activities, the implementation of the flipped classroom structure
and suggestions for how student engagement in higher order learning
might be improved in future iterations of the class are described
herein
Using Flipped Classroom Modules to Facilitate Higher Order Learning in Undergraduate Organic Chemistry
In an ongoing effort to incorporate active learning and
promote
higher order learning outcomes in undergraduate organic chemistry,
a hybrid (“flipped”) classroom structure has been used
to facilitate a series of collaborative activities in the first two
courses of the lower division organic chemistry sequence. An observational
study of seven classes over a five-year period reveals there is a
strong correlation between performance on the in-class activities
and performance on the final exam across all classes; however, a significant
number of students in these courses continue to struggle on both the
in-class activities and final exam. The Activity Engagement Survey
(AcES) was administered in the most recent course offering included
in this study, and these preliminary data suggest that students who
achieved lower scores on the in-class activities had lower levels
of emotional and behavioral/cognitive engagement and were less likely
to work in collaborative groups. In total, these findings suggest
that if students can be guided to engage more successfully with the
in-class activities, they are likely to be more successful in carrying
out the higher order learning required on the final exam. In addition
to the analyses of student performance and engagement in the in-class
activities, the implementation of the flipped classroom structure
and suggestions for how student engagement in higher order learning
might be improved in future iterations of the class are described
herein