Low-Dose 5-Aza and DZnep Alleviate Acute Graft-Versus-Host Disease With Less Side Effects Through Altering T-Cell Differentiation.

Objective: Previous studies showed that hypomethylating agents (HMAs) could alleviate acute graft-versus-host disease (aGvHD), but affect engraftment after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The combination of two different HMAs in lower doses might overcome this problem. This study aimed to evaluate the treatment effect of the combination of two HMAs-azacitidine (5-Aza) and histone H3K27 methyltransferase inhibitor 3-deazaneplanocin (DZNep)-for the prophylaxis of aGvHD after allo-HSCT and to explore the possible mechanisms. Methods: We first optimized the concentrations of individual and combinational 5-Aza and DZNep treatments to ensure no obvious toxicities on activated T cells by evaluating T-cell proliferation, viability, and differentiation. A mouse model of aGvHD was then established to assess the prophylactic efficacy of 5-Aza, DZNep, and their combination on aGvHD. The immunomodulatory effect on T cells and the hematopoietic reconstruction were assessed. Additionally, RNA sequencing (RNA-seq) was performed to identify the underlying molecular mechanisms. Results: Compared with single treatments, the in vitro application of 5-Aza with DZNep could more powerfully reduce the production of T helper type 1 (Th1)/T cytotoxic type 1 (Tc1) cells and increase the production of regulatory T cells (Tregs). In an allo-HSCT mouse model, in vivo administration of 5-Aza with DZNep could enhance the prophylactic effect for aGvHD compared with single agents. The mechanism study demonstrated that the combination of 5-Aza and DZNep in vivo had an enhanced effect to inhibit the production of Th1/Tc1, increase the proportions of Th2/Tc2, and induce the differentiation of Tregs as in vitro. RNA-seq analysis revealed the cytokine and chemokine pathways as one mechanism for the alleviation of aGvHD with the combination of 5-Aza and DZNep. Conclusion: The combination of 5-Aza and DZNep could enhance the prophylactic effect for aGvHD by influencing donor T-cell differentiation through affecting cytokine and chemokine pathways. This study shed light on the effectively prophylactic measure for aGvHD using different epigenetic agent combinations.

Decitabine-Containing Conditioning Regimen for Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Intermediate- and High-Risk Myelodysplastic Syndrome/Acute Myeloid Leukemia: Potential Decrease in the Incidence of Acute Graft versus Host Disease.

PURPOSE: To evaluate the role of Decitabine in the allo-HSCT conditioning regimen for intermediate- and high-risk patients with MDS or AML. PATIENTS AND METHODS: Retrospective analysis of data pertaining to 76 intermediate- and high-risk patients with MDS or AML who underwent allo-HSCT between December 2005 and June 2018 at the Peking University First Hospital. Forty patients received Decitabine-containing conditioning regimen before transplantation, while thirty-six patients received regimen without Decitabine. RESULTS: Over a median follow-up of 40 months (range, 1 to 155), the cumulative incidence of grade II to IV acute graft versus host disease was 12.4% [95% confidence interval (CI) 4.9-30.9%] in the Decitabine group and 41.5% (95% CI 28.1-61.2%) in the non-Decitabine group (P=0.005). On multivariate analysis, Decitabine-containing conditioning regimen was found to protect against grade II to IV aGVHD (HR=0.279, 95% CI 0.102-0.765, P=0.013). Incidence of respiratory infection in the Decitabine and non-Decitabine groups was 22.5% and 52.78%, respectively (P=0.012). No significant between-group difference was observed with respect to 3-year OS, DFS, or RR (P=0.980, 0.959, and 0.573, respectively), while the median relapse time was longer in the Decitabine group [7 months (range, 2-12) versus 3 months (range, 2-4), P=0.171]. Decitabine-containing conditioning showed a tendency for lower relapse rate among higher risk patients, as assessed by IPSS R; however, the between-group difference was not statistically significant (P=0.085). CONCLUSION: Inclusion of Decitabine in the conditioning regimen for allo-HSCT in intermediate- and high-risk patients may lower the incidence of aGVHD and respiratory infections, and contribute to longer median relapse time.

Characterization of ACC deaminase-producing endophytic bacteria isolated from copper-tolerant plants and their potential in promoting the growth and copper accumulation of Brassica napus.

One hundred Cu-resistant-endophytic bacteria were isolated from Cu-tolerant plants grown on Cu mine wasteland, of which, eight Cu-resistant and 1-aminocyclopropane-1-carboxylate (ACC) deaminase-producing endophytic bacteria were obtained based on the ACC deaminase activity of the bacteria and characterized with respect to metal resistance, production of ACC deaminase, indole-3-acetic acid (IAA) as well as siderophores and mineral phosphate solubilization. Ralstonia sp. J1-22-2, Pantoea agglomerans Jp3-3, and Pseudomonas thivervalensis Y1-3-9 with higher ACC deaminase activity (ranging from 213 to 370 µM α-ketobutyrate mg(-1)h(-1)) were evaluated for promoting plant growth and Cu uptake of rape grown in quartz sand containing 0, 2.5, and 5 mg kg(-1) of Cu in pot experiments. The eight bacteria were found to exhibit different multiple heavy metal resistance characteristics, to show different levels of ACC deaminase activity and to produce indole acetic acid. Seven bacteria produced siderophores and solubilized inorganic phosphate. Pot experiments showed that inoculation with the strains (J1-22-2, Jp3-3, and Y1-3-9) was found to increase the biomass of rape. Increases in above-ground tissue Cu contents of rape cultivated in 2.5 and 5 mg kg(-1) of Cu-contaminated substrates varied from 9% to 31% and from 3 to 4-fold respectively in inoculated-rape plants compared to the uninoculated control. The maximum Cu uptake of rape was observed after inoculation with P. agglomerans Jp3-3. The results show that metal-resistant and plant growth promoting endophytic bacteria play an important role in plant growth and Cu uptake which may provide a new endophytic bacterial-assisted phytoremediation of Cu-contaminated environment.

Characterization of lead-resistant and ACC deaminase-producing endophytic bacteria and their potential in promoting lead accumulation of rape.

Forty-nine lead (Pb)-resistant endophytic bacteria were isolated from metal-tolerant Commelina communis plants grown on lead and zinc mine tailing, of which, seven 1-aminocyclopropane-1-carboxylate (ACC) deaminase-producing endophytic bacteria were initially obtained and characterized with respect to heavy metal resistance and production of ACC deaminase, indole-3-acetic acid (IAA) as well as siderophores. Two isolates (Q2BJ2 and Q2BG1) showing higher ACC deaminase activity were evaluated for promoting plant growth and Pb uptake of rape grown in quartz sand containing 0 and 100 mg kg(-1) of Pb in pot experiments. The seven Pb-resistant and ACC deaminase-producing endophytic bacterial isolates were found to exhibit different multiple heavy metal resistance characteristics and to show different levels of ACC deaminase activity (ranging from 12.8 µM α-KB mg(-1) h(-1) to 121 µM α-KB mg(-1) h(-1)). Among the seven isolates, six isolates produced indole acetic acid, whilst five isolates produced siderophores. In experiments involving rape plants grown in quartz sand containing 100 mg kg(-1) of Pb, inoculation with the isolates resulted in the increased dry weights of above-ground tissues (ranging from 39% to 71%) and roots (ranging from 35% to 123%) compared to the uninoculated control. Increases in above-ground tissue Pb contents of rape cultivated in 100 mg kg(-1) of Pb-contaminated substrates varied from 58% to 62% in inoculated-rape plants compared to the uninoculated control.

The plant growth-promoting rhizobacterium Bacillus cereus AR156 induces systemic resistance in Arabidopsis thaliana by simultaneously activating salicylate- and jasmonate/ethylene-dependent signaling pathways.

Bacillus cereus AR156 is a plant growth-promoting rhizobacterium that induces resistance against a broad spectrum of pathogens including Pseudomonas syringae pv. tomato DC3000. This study analyzed AR156-induced systemic resistance (ISR) to DC3000 in Arabidopsis ecotype Col-0 plants. Compared with mock-treated plants, AR156-treated ones showed an increase in biomass and reductions in disease severity and pathogen density in the leaves. The defense-related genes PR1, PR2, PR5, and PDF1.2 were concurrently expressed in the leaves of AR156-treated plants, suggesting simultaneous activation of the salicylic acid (SA)- and the jasmonic acid (JA)- and ethylene (ET)-dependent signaling pathways by AR156. The above gene expression was faster and stronger in plants treated with AR156 and inoculated with DC3000 than that in plants only inoculated with DC3000. Moreover, the cellular defense responses hydrogen peroxide accumulation and callose deposition were induced upon challenge inoculation in the leaves of Col-0 plants primed by AR156. Also, pretreatment with AR156 led to a higher level of induced protection against DC3000 in Col-0 than that in the transgenic NahG, the mutant jar1 or etr1, but the protection was absent in the mutant npr1. Therefore, AR156 triggers ISR in Arabidopsis by simultaneously activating the SA- and JA/ET-signaling pathways in an NPR1-dependent manner that leads to an additive effect on the level of induced protection.

Genetic diversity and characterization of heavy metal-resistant-endophytic bacteria from two copper-tolerant plant species on copper mine wasteland.

The diversity of endophytic bacteria from the copper-tolerant species Elsholtzia splendens and Commelina communis was evaluated by using cultivation and cultivation-independent techniques. Phylogenetic analysis based on 16S rDNA sequences showed that the Cu-resistant isolates belonged to three major phylogenetic groups: Firmicutes, Actinobacteria and Proteobacteria. Bacillus and Acinetobacter were predominant among the Cu-resistant isolates. Sequence analysis from the 16S rDNA clone libraries of the two plant roots revealed sequences of Alpha-, Beta-, Gamma-Proteobacteria, Firmicutes,Actinobacteria and Bacteroidetes. Gammaproteobacteria was predominant in the two 16S rDNA clone libraries. Thirty-two endophytic bacteria were isolated and characterized with respect to heavy metal resistance and production of plant growth-promoting factors. In experiments involving rape plants grown in vermiculite containing 4 mg kg(-1) of Cu, inoculation with the isolates was found to increase the dry weights of roots (ranging from 132% to 155%) and above-ground tissues (ranging from 71% to 83%) compared to the uninoculated control. Increase in above-ground tissue Cu content varied from 63% to 125% in inoculated-rape plants cultivated in Cu-contaminated substrate compared to the uninoculated control.

Isolation and characterization of a heavy metal-resistant Burkholderia sp. from heavy metal-contaminated paddy field soil and its potential in promoting plant growth and heavy metal accumulation in metal-polluted soil.

A heavy metal-resistant bacterial strain was isolated from heavy metal-contaminated soils and identified as Burkholderia sp. J62 based on the 16S rDNA gene sequence analysis. The heavy metal- and antibiotic resistance, heavy metal solubilization of the isolate were investigated. The isolate was also evaluated for promoting plant growth and Pb and Cd uptakes of the plants from heavy metal-contaminated soils in pot experiments. The isolate was found to exhibit different multiple heavy metal and antibiotic resistance characteristics. Atomic absorption spectrometer analysis showed increased bacterial solubilization of lead and cadmium in solution culture and in soils. The isolate produced indole acetic acid, siderophore and 1-aminocyclopropane-1-carboxylate deaminase. The isolate also solubilized inorganic phosphate. Inoculation with the isolate was found to significantly (p<0.05) increase the biomass of maize and tomato plants. Increase in tissue Pb and Cd contents varied from 38% to 192% and from 5% to 191% in inoculated plants growing in heavy metal-contaminated soils compared to the uninoculated control, respectively. These results show that heavy metal-solubilizing and plant growth promoting bacteria are important for plant growth and heavy metal uptake which may provide a new microbial enhanced-phytoremediation of metal-polluted soils.

[Study on morphological characteristics of pollen grains of Pinellia ternata in different populations].

OBJECTIVE: To study the genetic diversity of pollen grains morphologies of Pinellia ternata in different populations and supply palynological evidences for further research. METHOD: Pollen exine ultrastructure were compared for 18 populations growing under in the same environment by means of scanning electron microscope(SEM). RESULT AND CONCLUSION: Big difference was found in pollen size among populations of P. ternata: the mean value of seventeen populations of P. ternata with bulbils was 17.42 microm x 14.86 microm, the biggest of populations originated from Jangyan city is 20.43 micromx 18.16 microm, but the least originated from Peixian County is only 15.23 microm x 12.82 microm; the size of populations without bulbils originated from Linguo Temple side was only 13.23 microm x 11.98 microm and far less than of all populations with bulbils. The pollen surface of all populations sticks out with spines, varying in size and density, the base and top part of spinules was different among populations. The pollen grains patterns of germination apertures of P. ternata was likely to have colpate cover.

[Studies on sex identification and variation of endogenous hormones in female and male plants of Gynostemma pentaphyllum].

OBJECTIVE: To distinguish female and male plants of Gynostemma pentaphyllum quickly and accurately in the stage of seedling and to understand the relation between sex differentiation and endogenous plant hormone. METHOD: Stained methods of BTB and enzyme linked immuno-sorbent Assay were used. RESULT: 10 Hours after being dyed, the liquid extract of female plants turned into yellow, while extract of male ones turned green. There were obvious differences on iPAs and GA(1 + 3) contents but no differences on IAA and ABA contents between male and female plants during the stages of seedling and vegetative growth. CONCLUSION: BTB can be used for distinguishing female and male plants and there were a certain relation between sex and endogenous plant hormones.