In Situ Molecular Analysis of Plant Tissues by Live Single-Cell Mass Spectrometry

We report the development of a rapid, direct molecular analysis of live, single plant cells viewed under a video microscope in their natural environment. A nanoelectrospray tip was used to extract the contents of a single leaf, stem, or petal cell from <i>Pelargonium zonale</i>, and the samples were analyzed on an Orbitrap mass spectrometer by nanoelectrospray ionization. Around a thousand <i>m</i>/<i>z</i> peaks belonging to metabolites and other compounds in each sample were obtained and processed by using statistical tools to find the cell specific molecular peaks. Hybrid high-resolution mass spectrometry analysis was performed to confirm the structure of specific metabolites from the analyzed samples. This method is useful for identifying specific molecules in live single cells from plant tissue and will allow different cell types and stages from different sites in the plant to be compared with morphological observations

In Situ Molecular Analysis of Plant Tissues by Live Single-Cell Mass Spectrometry

We report the development of a rapid, direct molecular analysis of live, single plant cells viewed under a video microscope in their natural environment. A nanoelectrospray tip was used to extract the contents of a single leaf, stem, or petal cell from <i>Pelargonium zonale</i>, and the samples were analyzed on an Orbitrap mass spectrometer by nanoelectrospray ionization. Around a thousand <i>m</i>/<i>z</i> peaks belonging to metabolites and other compounds in each sample were obtained and processed by using statistical tools to find the cell specific molecular peaks. Hybrid high-resolution mass spectrometry analysis was performed to confirm the structure of specific metabolites from the analyzed samples. This method is useful for identifying specific molecules in live single cells from plant tissue and will allow different cell types and stages from different sites in the plant to be compared with morphological observations

Dried Saliva Spot (DSS) as a Convenient and Reliable Sampling for Bioanalysis: An Application for the Diagnosis of Diabetes Mellitus

This paper proposes the dried saliva spot (DSS) as a convenient sampling technique for bioanalysis. The analytical method with the DSS was used for the determination of d,l-lactic acid (d,l-LA) and the d/l ratio of diabetic patients and prediabetic persons for the simple screening of the disease. The d,l-LA in the DSS was labeled with a chiral reagent (DMT-3­(<i>S</i>)-Apy) for carboxylic acids and determined by UPLC-ESI-MS/MS. The limits of detection (signal-to-noise ratio (S/N) = 3) for the DSS analysis were on the amol level (∼30 amol). Because good stability, recovery, accuracy, and precision of the d,l-LA for the DSS method was also obtained from the proposed procedure, the DSS method was applied to the determination of the d- and l-isomers of LA of diabetic patients, and prediabetic and healthy persons. The d/l-LA ratio by the present DSS method and the HbA1c value in blood were well-correlated to the serious diabetic patients, whereas the relation in the prediabetic persons was not very good. The reason seems to be due to the rough saliva sampling, and not to the DSS method, because strict regulation was not requested for the prediabetic and healthy persons. In order to have a successful DSS analysis, the stability of the target molecule, the detection sensitivity to the target molecule, and the validated determination method are important