AI-2–mediated quorum sensing of E. coli is directly connected to sugar metabolism via the phosphocarrier HPr protein of PTS.

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.

The spiny mouse,Acomys cahirinusdisplays a unique wound healing ability with regeneration of all skin components in a scar-free manner. To identify orchestrators of this regenerative response we have performed proteomic analyses of skin fromAcomysandMus musculusbefore and after wounding. Of the ~2000 proteins identified many are expressed at similar levels inAcomysandMus, but there are significant differences. Following wounding inMusthe complement and coagulation cascades, PPAR signaling pathway and ECM-receptor interactions predominate. InAcomys, other pathways predominate including the Wnt, MAPK, the ribosome, proteasome, endocytosis and tight junction pathways. Notable amongAcomysspecific proteins are several ubiquitin-associated enzymes and kinases, whereas inMusimmuno-modulation proteins characteristic of inflammatory response are unique or more prominent. ECM proteins such as collagens are more highly expressed inMus, but likely more important is the higher expression of matrix remodeling proteases inAcomys. Another distinctive difference betweenAcomysandMuslies in the macrophage-produced arginase 1 is found inMuswhereas arginase 2 is found inAcomys. Thus, we have identified several avenues for experimental approaches whose aim is to reduce the fibrotic response that the typical mammal displays in response to wounding.

Glechoma hederacea var. longituba (GHL) is one of many herbal plants distributed worldwide and is known to contain various biologically useful antioxidant constituents. GHL has been used in folk remedies for various treatments and as favorable tea beverages. However, research on the precise analysis of ingredients in GHL extracts remains insufficient. In this study, compositional analysis has been conducted on polyphenolic ingredients in GHL hot water extracts. GHL samples collected from growing regions were incubated in hot water at 100 °C for 1 h. The polyphenolic constituents in the hot water extracts were analyzed using high performance liquid chromatography-high resolution mass spectrometry (HPLC-HR MS) and tandem mass spectrometry (HPLC-MS/MS) in negative ion mode. As a result, a total of seven compounds were identified as the major polyphenolic constituents. Interestingly, four constituents out of the identified substances were confirmed to be polyphenol glucuronide conjugates, in which glucuronidation was known to be an important metabolic process in polyphenol aglycone along with methylation and sulphation. This study can be applied for the quality control and standardization of GHL herbal samples and the monitoring of metabolic processes involved in the polyphenolic conjugates.

Mass spectrometry (MS)-based intact mass analysis and structural characterization of biotherapeutic proteins such as monoclonal antibodies (mAbs) are a crucial characterization approach from upstream drug development to downstream product analysis. Due to various endogenous modifications leading to the structural heterogeneity and several N-linked glycan species resulting in macro-heterogeneity, it is challenging to characterize the mAbs. Hence, it is essential to understand the micro-heterogeneity of such proteins with high level of complexity which may vary in charge, size, or hydrophobicity. The development of high-throughput native separation techniques hyphenated with MS with high sensitivity and excellent mass accuracy has improved the top/middle down analysis, intact mass detection, subunit analysis, enhanced sequence coverage, and accurate localization of site-specific modifications. In this review, we have focused on the critical inroads taken for the improvement in MS-based techniques to resolve the challenges related to analysis of mAbs. Various MS-based techniques and their role in high-order structural analysis and the progress in software development have been explained, and further, the challenges remaining have been discussed. Graphical Abstract