1.
Deuterium metabolic imaging - Back to the future.
De Feyter, HM, de Graaf, RA
Journal of magnetic resonance (San Diego, Calif. : 1997). 2021;:106932
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Abstract
Deuterium metabolic spectroscopy (DMS) and imaging (DMI) have recently been described as simple and robust MR-based methods to map metabolism with high temporal and/or spatial resolution. The metabolic fate of a wide range of suitable deuterated substrates, including glucose and acetate, can be monitored with deuterium MR methods in which the favorable MR characteristics of deuterium prevent many of the complications that hamper other techniques. The short T1 relaxation times lead to good MR sensitivity, while the low natural abundance prevents the need for water or lipid suppression. The sparsity of the deuterium spectra in combination with the low resonance frequency provides relative immunity to magnetic field inhomogeneity. Taken together, these features combine into a highly robust metabolic imaging method that has strong potential to become a dominant MR research tool and a viable clinical imaging modality. This perspective reviews the history of deuterium as a metabolic tracer, the use of NMR as a detection method for deuterium in vitro and in vivo and the recent development of DMS and DMI. Following a review of the NMR characteristics and the biological effects of deuterium, the promising future of DMI is outlined.
2.
On the role of NMR spectroscopy for characterization of antimicrobial peptides.
Porcelli, F, Ramamoorthy, A, Barany, G, Veglia, G
Methods in molecular biology (Clifton, N.J.). 2013;:159-80
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Abstract
Antimicrobial peptides (AMPs) provide a primordial source of immunity, conferring upon eukaryotic cells resistance against bacteria, protozoa, and viruses. Despite a few examples of anionic peptides, AMPs are usually relatively short positively charged polypeptides, consisting of a dozen to about a hundred amino acids, and exhibiting amphipathic character. Despite significant differences in their primary and secondary structures, all AMPs discovered to date share the ability to interact with cellular membranes, thereby affecting bilayer stability, disrupting membrane organization, and/or forming well-defined pores. AMPs selectively target infectious agents without being susceptible to any of the common pathways by which these acquire resistance, thereby making AMPs prime candidates to provide therapeutic alternatives to conventional drugs. However, the mechanisms of AMP actions are still a matter of intense debate. The structure-function paradigm suggests that a better understanding of how AMPs elicit their biological functions could result from atomic resolution studies of peptide-lipid interactions. In contrast, more strict thermodynamic views preclude any roles for three-dimensional structures. Indeed, the design of selective AMPs based solely on structural parameters has been challenging. In this chapter, we will focus on selected AMPs for which studies on the corresponding AMP-lipid interactions have helped reach an understanding of how AMP effects are mediated. We will emphasize the roles of both liquid- and solid-state NMR spectroscopy for elucidating the mechanisms of action of AMPs.