Hydrogen peroxide sulfenylates and inhibits the photorespiratory enzyme PGLP1 to modulate plant thermotolerance.

Climate change is resulting in more frequent and rapidly changing temperatures at both extremes that severely affect the growth and production of plants, particularly crops. Oxidative stress caused by high temperatures is one of the most damaging factors for plants. However, the role of hydrogen peroxide (H2O2) in modulating plant thermotolerance is largely unknown, and the regulation of photorespiration essential for C3 species remains to be fully clarified. Here, we report that heat stress promotes H2O2 accumulation in chloroplasts and that H2O2 stimulates sulfenylation of the chloroplast-localized photorespiratory enzyme 2-phosphoglycolate phosphatase 1 (PGLP1) at cysteine 86, inhibiting its activity and promoting the accumulation of the toxic metabolite 2-phosphoglycolate. We also demonstrate that PGLP1 has a positive function in plant thermotolerance, as PGLP1 antisense lines have greater heat sensitivity and PGLP1-overexpressing plants have higher heat-stress tolerance than the wild type. Together, our results demonstrate that heat-induced H2O2 in chloroplasts sulfenylates and inhibits PGLP1 to modulate plant thermotolerance. Furthermore, targeting CATALASE2 to chloroplasts can largely prevent the heat-induced overaccumulation of H2O2 and the sulfenylation of PGLP1, thus conferring thermotolerance without a plant growth penalty. These findings reveal that heat-induced H2O2 in chloroplasts is important for heat-caused plant damage.

Effects of alfalfa saponins on the production performance, serum biochemical factors, and immune factors in Small-Tailed Han sheep.

This study aimed to determine the potential effects of alfalfa saponins on the production performance, serum biochemical factors, and immune factors in sheep. Twenty Small-Tailed Han sheep were equally and randomly divided into Groups 1-4, fed with diets containing 0, 5, 10, and 20 g alfalfa saponins per kg, respectively, for 40 consecutive days. During the treatments, the body weight change was recorded for each sheep. Before, during, and after the treatments of alfalfa saponins, serum was collected from each group to compare the levels of biochemical and immune factors. All sheep were killed after the treatments, and the longissimus dorsi muscle was collected to compare the meat quality. The results validated the effects of alfalfa saponins on the growth performance and meat quality in Small-Tailed Han sheep, and the supplementation level of 10 g/kg was the best. Alfalfa saponins also had effects on the levels of biochemical factors in serum. However, both dose- and time-dependent effects were observed. After a shorter feeding period (14 days), the concentrations of cholesterol (CHOL) and low-density lipoprotein (LDL) in Groups 2, 3, and 4 were all lower than those in the control group; however, when alfalfa saponins were continuously fed, this effect was not apparent or even gone. Supplying alfalfa saponins increased serum concentrations of IgA, IgG, IgE, IgM, IL-1, IFN-α, and IFN-ß. And this effect was distinctly observed in Groups 3 and 4. Based on the current results, the alfalfa saponins concentration of 10 g/kg (for 14 consecutive days) could be suggested as the optimum ratio for good health conditions of Small-Tailed Han sheep.

Coordination of plant growth and abiotic stress responses by tryptophan synthase ß subunit 1 through modulation of tryptophan and ABA homeostasis in Arabidopsis.

To adapt to changing environments, plants have evolved elaborate regulatory mechanisms balancing their growth with stress responses. It is currently unclear whether and how the tryptophan (Trp), the growth-related hormone auxin, and the stress hormone abscisic acid (ABA) are coordinated in this trade-off. Here, we show that tryptophan synthase ß subunit 1 (TSB1) is involved in the coordination of Trp and ABA, thereby affecting plant growth and abiotic stress responses. Plants experiencing high salinity or drought display reduced TSB1 expression, resulting in decreased Trp and auxin accumulation and thus reduced growth. In comparison with the wild type, amiR-TSB1 lines and TSB1 mutants exhibited repressed growth under non-stress conditions but had enhanced ABA accumulation and stress tolerance when subjected to salt or drought stress. Furthermore, we found that TSB1 interacts with and inhibits ß-glucosidase 1 (BG1), which hydrolyses glucose-conjugated ABA into active ABA. Mutation of BG1 in the amiR-TSB1 lines compromised their increased ABA accumulation and enhanced stress tolerance. Moreover, stress-induced H2O2 disrupted the interaction between TSB1 and BG1 by sulfenylating cysteine-308 of TSB1, relieving the TSB1-mediated inhibition of BG1 activity. Taken together, we revealed that TSB1 serves as a key coordinator of plant growth and stress responses by balancing Trp and ABA homeostasis.

Retrospective analysis of the efficacy and influencing factors of autologous hematopoietic stem cell transplantation for multiple myeloma.

This study aims to review the clinical efficacy and factors affecting the treatment of multiple myeloma (MM) by autologous hematopoietic stem cell transplantation (ASCT). The clinical data of 47 patients with MM from the Department of Hematology of Henan Cancer Hospital from September 2010 to July 2018 were retrospectively analyzed. At pre-transplantation of autologous cells, 25.5% were in complete remission (CR), 14.9% were in very good partial remission (VGPR) and 59.6% were in partial remission (PR). Among these cases, one case had PR after three recurrences. At post-transplantation, 51% were in CR, including two cases who received double transplantations, 27.7% were in VGPR, and 21.3% were in PR. The median follow-up time was 27.6 months (4-96 months). The 3-year progression free survival (PFS) and overall survival (OS) were 47.9% and 79.6%, respectively. The Analysis of variance (ANOVA) results revealed that factors that affected OS were international staging system (ISS) stage (P = 0.002), CR and VGPR post-transplantation (P = 0.002), while factors that affected PFS were ISS stage (P = 0.005), pre-transplant induction therapy (P = 0.032), and disease risk stratification (P = 0.017). The curative effects for PFS were CR and VGPR pre-transplantation (P = 0.013) and post-transplantation (P = 0.011). The Cox multivariate regression analysis revealed that ISS stage and CR and VGPR post-transplantation were independent prognostic factors of OS. At post-transplantation, CR and VGPR, ISS stage, and pre-transplant induction therapy were independent prognostic factors for PFS. In conclusion, ASCT can improve the clinical efficacy and survival rate of MM patients. ISS stage, CR and VGPR post-transplantation are independent prognostic factors of OS and PFS, while pre-transplant induction therapy is an independent prognostic factor for PFS.

[Efficacy and Influencing Factors of Autologous Hematopoietic Stem Cell Transplantation for Multiple Myeloma: Retrospective Analysis].

OBJECTIVE: To analyze the clinical efficacy and possible influencing factors of autologous hematopoietic Stem cell transplantation (auto-HSCT) in the treatment of patients with multiple myeloma (MM). METHODS: Clinical data of 40 MM patients received auto-HSCT in the Department of Hematology of Henan Cancer Hospital from September 2010 to November 2017 were retrospectively analyzed, the clinical curative efficiency was summarized and the related factors were analyzed. RESULTS: The curative efficiency of the patients before transplantation was 9(22.5%) with complete remission(CR), 5(12.5%) with very good partial remission(VGPR), 26(65%) with partial remission(PR), respectively, one of them was PR after 3 recurrences. The curative efficiency after transplantation was 22(55%) with complete remission(CR), 12(30%) with very good partial remission(VGPR), 6(15%) with partial remission(PR), respectively. And 2 cases were CR after double transplantation. Median follow-up time was 28.4 (3.1 to 88) months,15 cases presented disease progression, 7 cases were dead, 3-year estimated progression-free survival(PFS) and overall survival(OS) rate were 45.1% and 82% respectively. Unvariate analysis showed that the OS was affected by ISS stage (P<0.05), CR and VGPR (P<0.05) after transplantation; PFS was affected by ISS stage (P<0.01), before transplantation induction therapy (27 cases with bortezomizomi or thalidomide) (P<0.05), disease risk stratification (6 cases in high risk group) (P<0.05) , CR and VGPR (P<0.05) before transplantation, CR and VGPR (P<0.01) after transplantation. Cox multivariate regression analysis showed that the independent prognostic factors for OS were ISS stage, CR and VGPR after transplantation; the independent prognostic factors for PFS were the CR, VGPR, ISS stage after transplantation and induction therapy before transplant. CONCLUSION: Auto-HSCT can improve the clinical efficacy and survival rate of MM patients; ISS stage, CR and VGPR after transplantation are independent prognostic factors for OS and PFS, and induction therapy before transplantation is also an independent prognostic factor for PFS.

CATALASE2 functions for seedling postgerminative growth by scavenging H2 O2 and stimulating ACX2/3 activity in Arabidopsis.

Increased fatty acid ß-oxidation is essential for early postgerminative growth in seedlings, but high levels of H2 O2 produced by ß-oxidation can induce oxidative stress. Whether and how catalase (CAT) functions in fine-tuning H2 O2 homeostasis during seedling growth remain unclear. Here, we report that CAT2 functions in early seedling growth. Compared to the wild type, the cat2-1 mutant, with elevated H2 O2 levels, exhibited reduced root elongation on sucrose (Suc)-free medium, mimicking soils without exogenous sugar supply. Treatment with the H2 O2 scavenger potassium iodide rescued the mutant phenotype of cat2-1. In contrast to the wild type, the cat2-1 mutant was insensitive to the CAT inhibitor 3-amino-1,2,4-triazole in terms of root elongation when grown on Suc-free medium, suggesting that CAT2 modulates early seedling growth by altering H2 O2 accumulation. Furthermore, like cat2-1, the acyl-CoA oxidase (ACX) double mutant acx2-1 acx3-6 showed repressed root elongation, suggesting that CAT2 functions in early seedling growth by regulating ACX activity, as this activity was inhibited in cat2-1. Indeed, decreased ACX activity and short root of cat2-1 seedlings grown on Suc-free medium were rescued by overexpressing ACX3. Together, these findings suggest that CAT2 functions in early seedling growth by scavenging H2 O2 and stimulating ACX2/3 activity.

WD40-REPEAT 5a functions in drought stress tolerance by regulating nitric oxide accumulation in Arabidopsis.

Nitric oxide (NO) generation by NO synthase (NOS) in guard cells plays a vital role in stomatal closure for adaptive plant response to drought stress. However, the mechanism underlying the regulation of NOS activity in plants is unclear. Here, by screening yeast deletion mutants with decreased NO accumulation and NOS-like activity when subjected to H2 O2 stress, we identified TUP1 as a novel regulator of NOS-like activity in yeast. Arabidopsis WD40-REPEAT 5a (WDR5a), a homolog of yeast TUP1, complemented H2 O2 -induced NO accumulation of a yeast mutant Δtup1, suggesting the conserved role of WDR5a in regulating NO accumulation and NOS-like activity. This note was further confirmed by using an Arabidopsis RNAi line wdr5a-1 and two T-DNA insertion mutants of WDR5a with reduced WDR5a expression, in which both H2 O2 -induced NO accumulation and stomatal closure were repressed. This was because H2 O2 -induced NOS-like activity was inhibited in the mutants compared with that of the wild type. Furthermore, these wdr5a mutants were more sensitive to drought stress as they had reduced stomatal closure and decreased expression of drought-related genes. Together, our results revealed that WDR5a functions as a novel factor to modulate NOS-like activity for changes of NO accumulation and stomatal closure in drought stress tolerance.