2 research outputs found
Compound Identification Using Partial and Semipartial Correlations for Gas Chromatography–Mass Spectrometry Data
Compound identification is a key component of data analysis
in
the applications of gas chromatography–mass spectrometry (GC-MS).
Currently, the most widely used compound identification is mass spectrum
matching, in which the dot product and its composite version are employed
as spectral similarity measures. Several forms of transformations
for fragment ion intensities have also been proposed to increase the
accuracy of compound identification. In this study, we introduced
partial and semipartial correlations as mass spectral similarity measures
and applied them to identify compounds along with different transformations
of peak intensity. The mixture versions of the proposed method were
also developed to further improve the accuracy of compound identification.
To demonstrate the performance of the proposed spectral similarity
measures, the National Institute of Standards and Technology (NIST)
mass spectral library and replicate spectral library were used as
the reference library and the query spectra, respectively. Identification
results showed that the mixture partial and semipartial correlations
always outperform both the dot product and its composite measure.
The mixture similarity with semipartial correlation has the highest
accuracy of 84.6% in compound identification with a transformation
of (0.53,1.3) for fragment ion intensity and <i>m</i>/<i>z</i> value, respectively
A <sup>1</sup>H HR-MAS NMR-Based Metabolomic Study for Metabolic Characterization of Rice Grain from Various <i>Oryza sativa</i> L. Cultivars
Rice
grain metabolites are important for better understanding of
the plant physiology of various rice cultivars and thus for developing
rice cultivars aimed at providing diverse processed products. However,
the variation of global metabolites in rice grains has rarely been
explored. Here, we report the identification of intra- or intercellular
metabolites in rice (<i>Oryza sativa</i> L.) grain powder
using a <sup>1</sup>H high-resolution magic angle spinning (HR-MAS)
NMR-based metabolomic approach. Compared with nonwaxy rice cultivars,
marked accumulation of lipid metabolites such as fatty acids, phospholipids,
and glycerophosphocholine in the grains of waxy rice cultivars demonstrated
the distinct metabolic regulation and adaptation of each cultivar
for effective growth during future germination, which may be reflected
by high levels of glutamate, aspartate, asparagine, alanine, and sucrose.
Therefore, this study provides important insights into the metabolic
variations of diverse rice cultivars and their associations with environmental
conditions and genetic backgrounds, with the aim of facilitating efficient
development and the improvement of rice grain quality through inbreeding
with genetic or chemical modification and mutation