Search

Nitric oxide (NO) and Jasmonic acid (JA) are two key signaling molecules involved in many and diverse biological pathways in plants. Growing evidence suggested that NO signaling interacts with JA signaling. In this work, Our experiment showed that NO exists in guard cell of Vicia faba L., and NO is involved in signal transduction of JAinduced stomata closuring: ( i ) JA enhances NO synthesis in guard cell; ( ii ) both JA and NO induced stomatal closure, and had dose response to their effects; (iii) there are synergetic correlation between JA and lower NO concentration in regulation of stomatal movement; (iv) JA-induced stomatal closure was largely prevented by 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), a specific NO scavenger. An inhibitor of NO synthase (NOS) in mammalian cells, NG-nitro-L-Arg-methyl eater (L-NAME) also inhibits plant NOS, repressing JA-induced NO generation and JA-induced stomatal closure. We presumed that NO mainly comes from NOS after JA treatment. [ABSTRACT FROM AUTHOR]

Although protein tyrosine phosphatases (PTPases) play an important role in signal transduction in animal cells, little is known about the function of PTPases in higher plants. Hydrogen peroxide (H2O2) and mitogen-activated protein kinases (MAPKs) are the critical components of ABA signaling pathway in guard cells. PTPase is an important regulator of MAPK, which is believed to mediate ABA-induced H2O2 generation in guard cells of Vicia faba L. Here, we investigate the possible role of PTPases in stomatal movement process. Phenylarsine oxide (PAO), a specific inhibitor of PTPases, could prevent ABA or H2O2-induced stomatal closure of Vicia faba L; furthermore, it could promote opening of the stomata closed by ABA or H2O2. The activity of PTPases can be effectively inhibited by PAO and H2O2. DTT had no effect on the PAO-induced inhibition of PTPases activity, but it could relieve the inhibition of H2O2 on PTPases activity. PAO could also inhibit the ABA-induced H2O2 generation in guard cells of Vicia faba L. These results suggested that PTPases is a critical signaling component in ABA-induced stomatal closure, and serve as targets for H2O2 lying on the signaling pathways downstream of ABA induced H2O2 generation. [ABSTRACT FROM AUTHOR]

Acetylcholine (ACh) is an important neurochemical transmitter in animals; it also exists in plants and plays a significant role in various kinds of physiological functions in plants. ACh has been known to induce the stomatal opening. By monitoring the changes of cytosolic Ca2+ with fluorescent probe Fluo-3 AM under the confocal microscopy, we found that exogenous ACh increased cytosolic Ca2+ concentration of guard cells of Vicia faba L. Muscarine, an agonist of muscarine acetylcholine receptor (mAChR), could do so as well. In contrast, atropine, the antagonist of mAChR abolished the ability of ACh to increase Ca2+ in guard cells. This mechanism is similar to mAChR in animals. When EGTA was used to chelate Ca2+ or ruthenium red to block Ca2+ released from vacuole respectively, the results showed that the increased cytosolic Ca2+ mainly come from intracellular Ca2+ store. The evidence supports that Ca2+ is involved in guard-cell response to ACh and that Ca2+ signal is coupled to mAChRs in ACh signal transduction in guard cells. [ABSTRACT FROM AUTHOR]

Investigates the protein tyrosine phosphatase (PTPase) in relation to the cellular signaling of ABA accumulation in response to water deficit. Indication that protein phosphatases may be involved in the cellular signaling in response to water deficit; Evolution of plants to cope with water deficit and other environmental stresses.

A cascadic sensing system was developed for detection of DNA target at ultralow concentration by a combination of magnetic nanoparticles (MNPs) and exonuclease III (Exo III)-induced cascade two-stage isothermal amplification in the study. An ingeniously designed capture hairpin probe (CHP) that integrates target-binding and signal transduction sequences within one multifunctional design was assembled on MNPs. Upon sensing of the analyte nucleic acid, the hairpin probe on MNPs could be opened and stepwise removed by Exo III accompanied by the releasing of target DNA for the successive hybridization and cleavage process and the generation of bare signal transduction sequences of CHP as a new trigger for next circular reaction. The new DNA triggers initiate hybridizing with hairpin DNA probe that contains a partially "caged" G-quadruplex sequence (GHP), forming a duplex structure and liberating the active G-quadruplex structure. Then, Exo III digests the resulting duplex domain, leading to the recycling of new DNA trigger and simultaneously generating numerous ZnPPIX/G-quadruplex supramolecular complexes with the help of the zinc (II)-protoporphyrin IX (ZnPPIX), as an optical label for amplified fluorescence sensing event. Finally, numerous liberated cascade ZnPPIX/G-quadruplex supramolecular complexes give a remarkable fluorescence response. Because of two-stage autocatalytic recycling amplification and the specifically catalyzed formation of ZnPPIX/G-quadruplex supramolecular complexes, this newly designed protocol provides a high sensitivity with a detection limit of 0.75 fM, can discriminate mismatched DNA from perfectly matched target DNA, and gives low matrix effect due to using MNPs as the separation and amplification elements in the real samples. Therefore, it holds great potential for early diagnosis in gene-related diseases. [ABSTRACT FROM AUTHOR]