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Rationale: Various medium formulations contain essential fatty acids at concentrations ranging from 10 to 100 mg/L. Accurate and precise lipid measurement in media is crucial for monitoring media quality and conducting studies on lipids in the context of cell culture. This study employed two‐dimensional gas chromatography (GC × GC) analyses to offer enhanced resolution, sensitivity, and separation performance compared to GC. Methods: Quantification of fatty acid methyl esters (FAMEs) in a medium was conducted using GC × GC combined with a high‐resolution mass spectrometer and flame ionization detector, considering potential interference from nonionic surfactant Tween 80, which was precipitated and removed by optimizing the concentration of cobalt thiocyanate (CTA) solution during pretreatment. This advanced analytical approach enabled identification of cis and trans isomers of identical molecular weights and determination of the location and number of double bonds in the same carbon number structure. Results: Our analysis identified 36 FAMEs within the C6–C24 region, and a 5% CTA solution was optimal for efficient removal of Tween 80 during lipid extraction. Additionally, this advanced method minimized FAME contamination and loss during pretreatment, thereby significantly reducing the sample volume required to detect trace levels of FAMEs. This improvement led to a fatty acid recovery rate of 106% while maintaining the average relative standard deviation for the target FAMEs of about 3%. Conclusions: Our research paves the way for future investigation into medium quality control and the role of fatty acids in cell culture. This offers the possibility for economical and effective trace quantification of fatty acids in complex media. [ABSTRACT FROM AUTHOR]

Cav1.2 channel phosphorylation plays an important role in regulating neuronal plasticity by action potential-dependent Ca2+ entry. Most studies of Cav1.2 regulation by phosphorylation have been reported in heart and muscles. Here, we identified phosphorylation sites of neuronal Cav1.2 channel protein purified from rat brain using mass spectrometry. The functional characterization of these phosphorylation sites showed altered voltage-dependent biophysical properties of the channel, without affecting current density. These results show that neuronal Cav1.2 channel is regulated by phosphorylation in a complex mechanism involving multiple phosphorylation sites. [ABSTRACT FROM AUTHOR]

Summary: The omics‐based studies are important for identifying characteristic proteins in plants to elucidate the mechanism of ACC deaminase producing bacteria‐mediated salt tolerance. This study evaluates the changes in the proteome of rice inoculated with ACC deaminase producing bacteria under salt‐stress conditions. Salt stress resulted in a significant decrease in photosynthetic pigments, whereas inoculation of Methylobacterium oryzae CBMB20 had significantly increased pigment contents under normal and salt‐stress conditions. A total of 76, 51 and 33 differentially abundant proteins (DAPs) were identified in non‐inoculated salt‐stressed plants, bacteria‐inoculated plants under normal and salt stress conditions respectively. The abundances of proteins responsible for ethylene emission and programmed cell death were increased, and that of photosynthesis‐related proteins were decreased in non‐inoculated plants under salt stress. However, bacteria‐inoculated plants had shown higher abundance of antioxidant proteins, RuBisCo and ribosomal proteins that are important for enhancing stress tolerance and improving plant physiological traits. Collectively, salt stress might affect plant physiological traits by impairing photosynthetic machinery and accelerating apoptosis leading to a decline in biomass. However, inoculation of plants with bacteria can assist in enhancing photosynthetic activity, antioxidant activities and ethylene regulation related proteins for attenuating salt‐induced apoptosis and sustaining growth and development. [ABSTRACT FROM AUTHOR]

Abstract Background The rice roots are highly salt-sensitive organ and primary root growth is rapidly suppressed by salt stress. Sucrose nonfermenting 1-related protein kinase2 (SnRK2) family is one of the key regulator of hyper-osmotic stress signalling in various plant cells. To understand early salt response of rice roots and identify SnRK2 signaling components, proteome changes of transgenic rice roots over-expressing OSRK1, a rice SnRK2 kinase were investigated. Results Proteomes were analyzed by two-dimensional electrophoresis and protein spots were identified by LC-MS/MS from wild type and OSRK1 transgenic rice roots exposed to 150 mM NaCl for either 3 h or 7 h. Fifty two early salt -responsive protein spots were identified from wild type rice roots. The major up-regulated proteins were enzymes related to energy regulation, amino acid metabolism, methylglyoxal detoxification, redox regulation and protein turnover. It is noted that enzymes known to be involved in GA-induced root growth such as fructose bisphosphate aldolase and methylmalonate semialdehyde dehydrogenase were clearly down-regulated. In contrast to wild type rice roots, only a few proteins were changed by salt stress in OSRK1 transgenic rice roots. A comparative quantitative analysis of the proteome level indicated that forty three early salt-responsive proteins were magnified in transgenic rice roots at unstressed condition. These proteins contain single or multiple potential SnRK2 recognition motives. In vitro kinase assay revealed that one of the identified proteome, calreticulin is a good substrate of OSRK1. Conclusions Our present data implicate that rice roots rapidly changed broad spectrum of energy metabolism upon challenging salt stress, and suppression of GA signaling by salt stress may be responsible for the rapid arrest of root growth and development. The broad spectrum of functional categories of proteins affected by over-expression of OSRK1 indicates that OSRK1 is an upstream regulator of stress signaling in rice roots. Enzymes involved in glycolysis, branched amino acid catabolism, dnaK-type molecular chaperone, calcium binding protein, Sal T and glyoxalase are potential targets of OSRK1 in rice roots under salt stress that need to be further investigated.