Systemic H2O2 signaling mediates epigallocatechin-3-gallate-induced cadmium tolerance in tomato.

Toxic heavy metal cadmium (Cd) reduces crop yield and threatens human health via the food chain. The bioactive flavonoid 'Epigallocatechin-3-gallate' (EGCG) affects plant stress response; however, the function of EGCG in Cd tolerance and the molecular pathways remain largely unknown. Here, we revealed that root application of EGCG alleviated Cd stress in tomato plants. While Cd stress decreased Fv/Fm, ФPSII, photosynthetic rate, root growth, root vitality and biomass accumulation by increasing reactive oxygen species (ROS) accumulation and lipid peroxidation, exogenous EGCG minimized excessive ROS accumulation and oxidative stress by promoting the activity of antioxidant enzymes and redox poise in roots and leaves. Moreover, EGCG induced the transcript of RESPIRATORY BURST OXIDASE HOMOLOG1 (RBOH1) and decreased Cd content and photoinhibition in leaves. Interestingly, similar to EGCG, exogenous H2O2 application also enhanced Cd tolerance; however, the application of an NADPH oxidase inhibitor, diphenyleneiodonium (DPI), aggravated Cd phytotoxicity and attenuated the beneficial effects of EGCG on plant tolerance to Cd stress, suggesting that root applied EGCG-induced expression of RBOH1 and associated H2O2 signaling mediate the EGCG-induced enhanced Cd tolerance. This work elucidates a fundamental mechanism behind EGCG-mediated Cd tolerance and contributes to our existing knowledge of stress resistance properties of EGCG in plants.

[Ultrasound-guided electroacupuncture at suprahyoid muscle group for pharyngeal dysphagia after stroke: a randomized controlled trial].

OBJECTIVE: To compare the effect among ultrasound-guided electroacupuncture (EA) at suprahyoid muscle group, conventional acupuncture and conventional EA at suprahyoid muscle group on pharyngeal dysphagia after stroke, and to explore its biomechanical mechanism. METHODS: A total of 120 patients with pharyngeal dysphagia after stroke were randomly divided into an observation group, a control-1 group and a control-2 group, 40 cases in each group. The patients in the observation group were treated with ultrasound-guided EA at suprahyoid muscle group; the patients in the control-1 group were treated with EA at Lianquan (CV 23), Wangu (GB 12) and Fengchi (GB 20), etc.; the patients in the control-2 group were treated with EA at suprahyoid muscle group according to anatomical location. The EA in the three groups were discontinuous wave, with frequency of 5 Hz and current intensity of 1 mA. The EA was given for 30 minutes, once a day, 6 times were taken as a course of treatment, and 4 courses of treatment were provided. The video floroscopic swallowing study (VFSS) was performed before and after treatment. The Rosenbek penetration-aspiration scale (PAS) score, the forward and upward movement distance of hyoid bone and thyroid cartilage, Ichiro Fujima ingestion-swallowing function score were recorded in the three groups, and the incidences of subcutaneous hematoma were recorded after treatment. RESULTS: Compared before treatment, the PAS scores were reduced and the Ichiro Fujima ingestion-swallowing function scores were increased after treatment in the three groups (P<0.05); the PAS scores in the observation group were lower than those in the control-1 group and the control-2 group, and the Ichiro Fujima ingestion-swallowing function scores in the observation group were higher than those in the control-1 group and the control-2 group (P<0.05). After treatment, the forward and upward movement distance of hyoid bone and thyroid cartilage in the observation group and the control-2 group was increased (P<0.05), and the forward and upward movement distance of hyoid bone was increased in the control-1 group (P<0.05); the forward and upward movement distance of hyoid bone and thyroid cartilage in the observation group was longer than that in the control-1 group and the control-2 group (P<0.05). The incidence of subcutaneous hematoma in the observation group was 0% (0/40), which was lower than 20.0% (8/40) in the control-1 group and 47.5% (19/40) in the control-2 group (P<0.05). CONCLUSION: Ultrasound-guided EA at suprahyoid muscle group could improve the swallowing function in patients with pharyngeal dysphagia after stroke by increasing the motion of hyoid laryngeal complex. Its effect and safety are better than conventional acupuncture and conventional EA at suprahyoid muscle group.

[Effect of electrical stimulation with bilateral scalp acupuncture on time parameters in video fluoroscopic swallowing study and cortical excitability in patients with dysphagia after cortical stroke].

OBJECTIVE: To investigate the effect of electrical stimulation with bilateral scalp acupuncture on time parameters in video fluoroscopic swallowing study and cortical excitability in patients with dysphagia after cortical stroke, as well as its possible mechanism of action. METHODS: A total of 84 patients with dysphagia after cortical stroke were randomly divided into control group with 41 patients and observation group with 43 patients. The patients in the control group were given acupuncture based on acupoint selection for pseudobulbar palsy, and in addition to the treatment in the control group, the patients in the observation group were given electrical stimulation of bilateral scalp acupuncture, with acupuncture and pulse acupuncture at the lower 2/5 of the bilateral anterior oblique parietotemporal lines[on the line connecting Qianshencong (EX-HN1) to Xuanli (GB6)] and the lower 2/5 of the bilateral posterior oblique parietotemporal lines [on the line connecting Baihui (GV20)and Qubin (GB7)], with a needle retaining time of 30 minutes, once a day and 6 times a week for 3 weeks. Before treatment and after 3 weeks of treatment, oral delay time (ODT), oral transit time (OTT), pharyngeal delay time (PDT), and pharyngeal transit time (PTT) were compared between the two group; the Rosenbek Penetration-Aspiration Scale was used to evaluate penetration-aspiration and appro-ximate entropy (ApEn) of EEG nonlinear index. RESULTS: After treatment, both groups had significant reductions in ODT, OTT, PDT, PTT, and Rosenbek Penetration-Aspiration score and a significant increase in ApEn (P<0.05). Compared with the control group after treatment, the observation group had significant reductions in ODT and OTT (P<0.05) and significant increases in the ApEn values of bilateral central, parietal, and posterior temporal regions (P<0.05), while there were no significant differences in PDT, PTT, and Rosenbek Penetration-Aspiration score between the two groups (P>0.05). CONCLUSION: In addition to body acupuncture, electrical stimulation with bilateral scalp acupuncture can improve ODT and OTT in the treatment of patients with dysphagia after cortical stroke, which may be associated with the increased excitability of the swallowing cortex.

[Activation tagging and its application in plant functional genomics research].

It is a practical strategy to screen for mutants in the research of plant functional genomics. Comparing with classical T-DNA knock-out mutagenesis technology by the loss-of-function mutation, the activation T-DNA tagging technique based on the gain-of-function mutation has its own particular advantages, mainly characterized by producing dominant mutants of genes with functional redundancy and easily cloning of the genes. First, the basic principle of activation tagging, and the progress of its application in the research on plant functional genomics was reviewed, especially in Arabidopsis and rice. The recent research progress in the mechanism of plant biotic and abiotic stress tolerance and of plant development unraveled by the method of activation tagging was then addressed. Finally, the limitation and prospects of this technique were discussed.

Expression of CycD3 is transiently increased by pollination and N-(2-chloro-4-pyridyl)-N'-phenylurea in ovaries of Lagenaria leucantha.

Lagenaria leucantha is an important vegetable crop and a potential model for the study of fruit development. To study the function of D cyclins in fruit development, full-length cDNA clones for two D cyclin genes were isolated from young ovaries of Lagenaria leucantha. They were classified as D3 cyclins by sequence similarities and phylogenetic analysis, and nominated LlCycD3;1 and LlCycD3;2, respectively. The deduced amino acid sequence of both LlCycD3 genes contained a retinoblastoma-binding motif and a PEST-destruction motif. Unpollinated ovaries failed to develop and eventually aborted. N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU) induced parthenocarpic fruit significantly larger than pollinated ones. In unpollinated ovaries, the expression of both LlCycD3 genes was abundant at anthesis and then suddenly decreased, concomitant with the cessation of cell division. Pollination/fertilization induced an activation of the cell cycle accompanied by a large increase in the transcript levels of LlCycD3;1 and LlCycD3;2 in young fruits. Treating ovaries with CPPU also reactivated cell division and transcription of CycD3 genes and the effect was more rapid and pronounced than after pollination/fertilization.