Search for: All records

The conformational transition of a fluorinated amphiphilic dendrimer is monitored by the¹H signal from water, alongside the¹⁹F signal from the dendrimer. High‐field NMR data (chemical shiftδ, self‐diffusion coefficientD, longitudinal relaxation rateR₁, and transverse relaxation rateR₂) for both dendrimer (¹⁹F) and water (¹H) match each other in detecting the conformational transition. Among all parameters for both nuclei, the water proton transverse‐relaxation rateR₂(¹H₂O) displays the highest relative scale of change upon conformational transition of the dendrimer. Hydrogen/deuterium‐exchange mass spectrometry reveals that the compact form of the dendrimer has slower proton exchange with water than the extended form. This result suggests that the sensitivity ofR₂(¹H₂O) toward dendrimer conformation originates, at least partially, from the difference in proton exchange efficiency between different dendrimer conformations. Finally, we also demonstrated that this conformational transition could be conveniently monitored using a low‐field benchtop NMR spectrometer viaR₂(¹H₂O). The¹H₂O signal thus offers a simple way to monitor structural changes of macromolecules using benchtop time‐domain NMR.

Sweet corn (Zea maysL.) is highly consumed in the United States, but does not make major contributions to the daily intake of carotenoids (provitamin A carotenoids, lutein and zeaxanthin) that would help in the prevention of health complications. A genome‐wide association study of seven kernel carotenoids and twelve derivative traits was conducted in a sweet corn inbred line association panel ranging from light to dark yellow in endosperm color to elucidate the genetic basis of carotenoid levels in fresh kernels. In agreement with earlier studies of maize kernels at maturity, we detected an association of β‐carotene hydroxylase(crtRB1) with β‐carotene concentration andlycopene epsilon cyclase(lcyE) with the ratio of flux between the α‐ and β‐carotene branches in the carotenoid biosynthetic pathway. Additionally, we found that 5% or less of the evaluated inbred lines possessing theshrunken2(sh2) endosperm mutation had the most favorablelycEallele orcrtRB1haplotype for elevating β‐branch carotenoids (β‐carotene and zeaxanthin) or β‐carotene, respectively. Genomic prediction models with genome‐wide markers obtained moderately high predictive abilities for the carotenoid traits, especially lutein, and outperformed models with less markers that targeted candidate genes implicated in the synthesis, retention, and/or genetic control of kernel carotenoids. Taken together, our results constitute an important step toward increasing carotenoids in fresh sweet corn kernels.