Antioxidant enzymes regulate reactive oxygen species during pod elongation in Pisum sativum and Brassica chinensis.

Previous research has focused on the involvement of reactive oxygen species (ROS) in cell wall loosening and cell extension in plant vegetative growth, but few studies have investigated ROS functions specifically in plant reproductive organs. In this study, ROS levels and antioxidant enzyme activities were assessed in Pisum sativum and Brassica chinensis pods at five developmental stages. In juvenile pods, the high levels of O2.- and .OH indicates that they had functions in cell wall loosening and cell elongation. In later developmental stages, high levels of .OH were also related to increases in cell wall thickness in lignified tissues. Throughout pod development, most of the O2.- was detected on plasma membranes of parenchyma cells and outer epidermis cells of the mesocarp, while most of the H2O2 was detected on plasma membranes of most cells throughout the mesocarp. This suggests that these sites are presumably the locations of ROS generation. The antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) apparently contributed to ROS accumulation in pod wall tissues. Furthermore, specifically SOD and POD were found to be associated with pod growth through the regulation of ROS generation and transformation. Throughout pod development, O2.- decreases were associated with increased SOD activity, while changes in H2O2 accumulation were associated with changes in CAT and POD activities. Additionally, high POD activity may contribute to the generation of(.)OH in the early development of pods. It is concluded that the ROS are produced in different sites of plasma membranes with the regulation of antioxidant enzymes, and that substantial ROS generation and accumulation are evident in cell elongation and cell wall loosening in pod wall cells

Study of Salidroside on Expression of Synaptophysin and Tau in Rats after Local Cerebral Ischemia-reperfusion Injury

Objective:To investigate the effect of salidroside on the expression of synaptophysin (SYN) and Tau in rats after cerebral ischemia-reperfusion injury.Methods:A total of 36 healthy adult male Sprague-Dawley rats were randomly divided into sham group (n=12) and model group (n=24). Cerebral ischemia model of middle cerebral artery occlusion (MCAO) was established in rats of model group using suture method, and the nerves function score was determined by Zeal Longa score after the animal model was fully awakened. Then the successful model rats were randomly divided into model group and salidroside group, twelve rats in each group. With occluding of middle cerebral arteries for two hours and reperfusion for 24 hours, the sham group and model group were treated with normal saline at a dose of 50 mg/kg, and the salidroside group received salidroside at a dose of 50 mg/kg by intraperitoneal injection. All rats were sacrificed 24 hours after MCAO operation. The rats were treated with drugs one more time at two hours before sacrifice. The mRNA expression of SYN and Tau in ischemic brain tissue were detected by RT-qPCR, the protein expression of phosphorylated Tau at threonine 231 (p-Tau231) was detected by immunohistochemical method, and the protein expression of SYN and p-Tau231 in ischemic brain tissue were detected by Western Blot.Results:Compared with the sham group, SYN expression in model group was decreased (P<0.05);SYN expression in salidroside group was increased compared with the model group (P<0.05); p-Tau231 expression in model group was increased compared with the sham group (P<0.01). p-Tau231 expression in salidroside group was decreased compared with model group (P<0.01).Conclusion:Salidroside can increase the injury-induced downregulation of SYN when the injury caused by MCAO, and decrease hyperphosphorylation of Tau protein in the ipsilateral thalamus of rats after cerebral ischemia-reperfusion injury

Correlation coefficients between either pod length or pod wall thickness and either SOD activity, POD activity, CAT activity, or the level of either O₂^.−,^.OH, H₂O₂ during pod development.

<p>PL, pod length; PWT, pod wall thickness. n = 5–8.</p

Pod wall thickness, pod length, ROS quantitation and activities of SOD, POD, and CAT in pod walls of <i>P. sativum</i> and <i>B. chinensis</i> throughout the five developmental stages.

<p>A sample was collected from both species during each stage of pod development; these samples consisted of five to eight pods in which each pod only collected from one plant. Data are shown as means ± SD. Within each column, a means is given followed by a lowercase letter for <i>P. sativum</i> and by an uppercase letter for <i>B. chinensis</i>; if the letter is not the same as in the row above, that indicates that the means were statistically different at p<0.05.</p

The biosynthesis and degradation of reactive oxygen species (O₂^.⁻<b>, H₂O₂, and^.OH).</b>

<p>The scheme illustrating reactive oxygen species dynamics in the wall and plasma membrane of plant cells is revised according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0087588#pone.0087588-PerlTreves1" target="_blank">[3]</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0087588#pone.0087588-Schopfer1" target="_blank">[4]</a>. NOX: NADPH Oxidases.</p

Generation of the hydroxyl radical (^.OH) in the extracts of the pod walls.

<p>^.OH of <i>P. sativum</i> and <i>B. chinensis</i> was detected throughout the five developmental stages. The peak values of <i>P. sativum</i> were 36.2±4.0, 26.1±3.4, 23.8±2.1, 29.1±2.7, 32.1±3.0 during pod development from stages 1 to 5. And the peak values of were <i>B. chinensis</i> 57.8±4.9, 57.6±4.2, 47.1±3.9, 48.6±2.8, 57.0±3.6 mm from developmental stages 1 to 5. A sample was collected from both species during each stage of pod development; these samples consisted of five to eight pods, and each pod was separately collected from a different plant. Levels of.OH are expressed as relative fluorescence intensity and were measured using terephthalic acid (TPA) as a hydroxyl radical dosimeter. A: <i>P. sativum</i>; B: <i>B. chinensis</i>.</p

Structural features and thickness of pod walls.

<p>Structures of <i>P. sativum</i> (left column) and <i>B. chinensis</i> (right column) in pods at each developmental stage (from top to down) were detected by light micrographs. Each panel represents microscopic observations of one transverse section of each pod from five replications. A sample was collected from both species during each stage of pod development; these samples consisted of five pods, and each pod was separately collected from a different plant. OE: outer epidermis (exocarp); IE: inner epidermis (endocarp); P: parenchyma (mesocarp); VB: vascular bundle, C: cuticle. Mean pod cell width of <i>P. sativum</i> were 0.029±0.008, 0.033±0.011, 0.052±0.015, 0.063±0.021, 0.083±0.030 mm, and of <i>B. chinensis</i> were 0.014±0.005, 0.024±0.009, 0.028±0.007, 0.035±0.012, 0.053±0.018 mm.</p

Cytochemical localization of reactive oxygen species in pod walls.

<p>O₂^.− (A, B) and H₂O₂ (C, D) in transverse sections of pod walls of <i>P. sativum</i> (A, B) and <i>B. chinensis</i> (B, D) were detected. Each panel represents microscopic observations of one transverse section of each pod from five replications. A sample was collected from both species; these samples consisted of five pods and each pod was separately collected from a different plant. O₂.⁻ and H₂O₂ were detected by NBT and DAB staining, respectively.</p