Insights into non-symbiotic plant growth promotion bacteria associated with nodules of Sphaerophysa salsula growing in northwestern China.

In addition to rhizobia, other non-symbiotic endophytic bacteria also have been simultaneously isolated from the same root nodules. The existence of non-symbiotic endophytic bacteria in leguminous root nodules is a universal phenomenon. The vast majority of studies have detected endophytic bacteria in other plant tissues. In contrast, little systemic observation has been made on the non-symbiotic endophytic bacteria within leguminous root nodules. The present investigation was carried out to isolate plant growth-promoting endophytic non-symbiotic bacteria from indigenous leguminous Sphaerophysa salsula and their influence on plant growth. A total of 65 endophytic root nodule-associated bacteria were isolated from indigenous legume S. salsula growing in the northwestern arid regions of China. When combining our previous work with the current study, sequence analysis of the nifH gene revealed that the strain belonging to non-nodulating Bacillus pumilus Qtx-10 had genes similar to those of Rhizobium leguminosarum Qtx-10-1. The results indicated that horizontal gene transfer could have occurred between rhizobia and non-symbiotic endophyties. Under pot culture conditions, out of the 20 representative endophytic isolates, 15 with plant growth-promoting traits, such as IAA production, ACC deaminase, phosphate solubilization, chitinase, siderophore, and fungal inhibition activity showed plant growth-promoting activity with respect to various plant parameters such as chlorophyll content, fresh weight of plant, shoot length, nodule number per plant and average nodule weight per plant when co-inoculated with rhizobial bioinoculant Mesorhizobium sp. Zw-19 under N-free culture conditions. Among them, Bacillus pumilus Qtx-10 and Streptomyces bottropensis Gt-10 were excellent plant growth-promoting bacteria, which enhanced the seeding fresh weight by 87.5% and the shoot length by 89.4%, respectively. The number of nodules grew more than 31.89% under field conditions. Our findings indicate the frequent presence of these non-symbiotic endophytic bacteria within root nodules, and that they help to improve nodulation and nitrogen fixation in legume plants through synergistic interactions with rhizobia.

The Root Endophytic Fungi Community Structure of Pennisetum sinese from Four Representative Provinces in China.

Pennisetum sinese is a good forage grass with high biomass production and crude proteins. However, little is known about the endophytic fungi diversity of P. sinese, which might play an important role in the plant's growth and biomass production. Here, we used high throughput sequencing of the Internal Transcribed Spacer (ITS) sequences based on primers ITS5-1737 and ITS2-2043R to investigate the endophytic fungi diversity of P. sinese roots at the maturity stage, as collected from four provinces (Shaanxi province, SX; Fujian province, FJ; the Xinjiang Uyghur autonomous prefecture, XJ and Inner Mongolia, including sand (NS) and saline-alkali land (NY), China). The ITS sequences were processed using QIIME and R software. A total of 374,875 effective tags were obtained, and 708 operational taxonomic units (OTUs) were yielded with 97% identity in the five samples. Ascomycota and Basidiomycota were the two dominant phyla in the five samples, and the genera Khuskia and Heydenia were the most abundant in the FJ and XJ samples, respectively, while the most abundant tags in the other three samples could not be annotated at the genus level. In addition, our study revealed that the FJ sample possessed the highest OTU numbers (242) and the NS sample had the lowest (86). Moreover, only 22 OTUs were present in all samples simultaneously. The beta diversity analysis suggested a division of two endophytic fungi groups: the FJ sample from the south of China and the other four samples from north or northwest China. Correlation analysis between the environmental factors and endophytic fungi at the class level revealed that Sordariomycetes and Pucciniomycetes had extremely significant positive correlations with the total carbon, annual average precipitation, and annual average temperature, while Leotiomycetes showed an extremely significant negative correlation with quick acting potassium. The results revealed significant differences in the root endophytic fungi diversity of P. sinese in different provinces and might be useful for growth promotion and biomass production in the future.

Root-Associated Endophytic Bacterial Community Composition of Pennisetum sinese from Four Representative Provinces in China.

Pennisetum sinese, a source of bio-energy with high biomass production, is a species that contains high crude protein and will be useful for solving the shortage of forage grass after the implementation of "Green for Grain" project in the Loess plateau of Northern Shaanxi in 1999. Plants may receive benefits from endophytic bacteria, such as the enhancement of plant growth or the reduction of plant stress. However, the composition of the endophytic bacterial community associated with the roots of P. sinese is poorly elucidated. In this study, P. sinese from five different samples (Shaanxi province, SX; Fujian province, FJ; the Xinjiang Uyghur autonomous prefecture, XJ and Inner Mongolia, including sand (NS) and saline-alkali land (NY), China) were investigated by high-throughput next-generation sequencing of the 16S rDNA V3-V4 hypervariable region of endophytic bacteria. A total of 313,044 effective sequences were obtained by sequencing five different samples, and 957 effective operational taxonomic units (OTUs) were yielded at 97% identity. The phylum Proteobacteria, the classes Gammaproteobacteria and Alphaproteobacteria, and the genera Pantoea, Pseudomonas, Burkholderia, Arthrobacter, Psychrobacter, and Neokomagataea were significantly dominant in the five samples. In addition, our results demonstrated that the Shaanxi province (SX) sample had the highest Shannon index values (3.795). We found that the SX (308.097) and NS (126.240) samples had the highest and lowest Chao1 richness estimator (Chao1) values, respectively. Venn graphs indicated that the five samples shared 39 common OTUs. Moreover, according to results of the canonical correlation analysis (CCA), soil total carbon, total nitrogen, effective phosphorus, and pH were the major contributing factors to the difference in the overall composition of the bacteria community in this study. Our data provide insights into the endophytic bacteria community composition and structure of roots associated with P. sinese. These results might be useful for growth promotion in different samples, and some of the strains may have the potential to improve plant production in future studies.

Human Umbilical Cord Mesenchymal Stem Cells Therapy for Insulin Resistance: A Novel Strategy in Clinical Implication.

There is increasing evidence reporting that as a common phenomenon in MetS relative diseases, insulin resistance (IR) is regarded as an independent etiological factor and a warning indicator of MetS occurrence. Therefore, for the special group (overweight or obesity), clinical regular monitoring of IR is an important basis for the prevention and early intervention of MetS relative diseases. This surveys reveals that human umbilical cord mesenchymal stem cells (HUC-MSCs)possess a kind of potential: it may become a possible theraphy for IR in type 2 diabetes mellitus (T2DM) and related diseases. Specific emphasis is focused on evaluating the improvement IR function of HUC-MSCs under the background of development in vitro and in vivo. Next, the action mechanisms of HUC-MSCs is discussed, and some of their advantages and disadvantages in the course of clinic application are presented. The final section highlights the application of HUC-MSCs in T2DM and relative diseases at this stage. Up to now, although many questions remain unresolved, we still consider that HUC-MSCs is one of the best therapy ameliorating IR in the future.

[Comprehensive Effects of the Application of Water and Fertilizer Amount on CO2 Emission from Soils of Summer-maize Field].

Field experiments were conducted to determine the effects of water and fertilizer amount on soil CO2 emissions by using the method of static chamber/gas chromatography in summer maize farmland ecosystem. Three factors (three irrigation levels including 90 mm, 76.5 mm and 63 mm, four nitrogen fertilizer levels including 300 kg·hm-2, 255 kg·hm-2, 210 kg·hm-2 and 0 kg·hm-2, and four phosphate fertilizer levels including 90 kg·hm-2, 76.5 kg·hm-2, 63 kg·hm-2 and 0 kg·hm-2) were designed in the experiment. The results showed that soil CO2 emission under different water and fertilizer conditions showed obvious seasonal fluctuation, the main and secondary peak appeared at jointing to tasseling stage and tasseling to grouting stage. The soil CO2 emissions were relevant to the supply levels of fertilizer and irrigation. In the high fertilizer F1 (N 300 kg·hm-2, P2O5 90 kg·hm-2) and low fertilizer F0.7 (N 210 kg·hm-2, P2O5 63 kg·hm-2) conditions, average soil CO2 emissions flux during the whole growth period of high water W1 (90 mm) was significantly higher than that of low water W0.7 (63 mm); the difference of soil CO2 emissions between medium water level W0.85 (76.5 mm) and low water level was not significant under medium and low nutrient condition F0.85 (N 255 kg·hm-2, P2O5 76.5 kg·hm-2). Soil CO2 emissions intensity of high fertilizer F1 was significantly larger (by 14.82%) than that of low fertilizer F0.7 under high water supply W1 (P<0.05), and that of F0.85 was significantly bigger (by 8.03%) than that of F0.7 in the medium water supply(P<0.05), while the difference between treatments at low water level was not significant(P>0.05). Compared with nonfertilized treatment, soil CO2 cumulative emissions of the whole growth period with application of nitrogen fertilizer (210 kg·hm-2), phosphate fertilizer (63 kg·hm-2) and nitrogen mixed with phosphate fertilizer (210 kg·hm-2, 63 kg·hm-2) were significantly increased by 23.70%, 19.00% and 12.30%, respectively. And interaction effects between nitrogen and phosphorus fertilizer were extremely significant (P<0.01). Variance analysis of the interaction of water and fertilizer showed that the average soil CO2 fluxes of the whole growth period were not statistically significant but cumulative emissions of soil CO2 were significant (P<0.05) when the difference of supply level was 15%. In addition, soil CO2 flux and cumulative emission in the whole growth period were significant when supply differed by 30%. Obviously, soil CO2 emissions were promoted significantly by application of irrigation amount, nitrogen fertilizer, phosphorus rate and water and fertilizer interaction, while it was inhibited by nitrogen mixed with phosphorus. It was effective to regulate soil CO2 emission by water and fertilizer controlling measures.

Biomechanical comparison of a novel transoral atlantoaxial anchored cage with established fixation technique - a finite element analysis.

BACKGROUND: The transoral atlantoaxial reduction plate (TARP) fixation has been introduced to achieve reduction, decompression, fixation and fusion of C1-C2 through a transoral-only approach. However, it may also be associated with potential disadvantages, including dysphagia and load shielding of the bone graft. To prevent potential disadvantages related to TARP fixation, a novel transoral atlantoaxial fusion cage with integrated plate (Cage + Plate) device for stabilization of the C1-C2 segment is designed. The aims of the present study were to compare the biomechanical differences between Cage + Plate device and Cage + TARP device for the treatment of basilar invagination (BI) with irreducible atlantoaxial dislocation (IAAD). METHODS: A detailed, nonlinear finite element model (FEM) of the intact upper cervical spine had been developed and validated. Then a FEM of an unstable BI model treated with Cage + Plate fixation, was compared to that with Cage + TARP fixation. All models were subjected to vertical load with pure moments in flexion, extension, lateral bending and axial rotation. Range of motion (ROM) of C1-C2 segment and maximum von Mises Stress of the C2 endplate and bone graft were quantified for the two devices. RESULTS: Both devices significantly reduced ROM compared with the intact state. In comparison with the Cage + Plate model, the Cage + TARP model reduced the ROM by 82.5 %, 46.2 %, 10.0 % and 74.3 % in flexion, extension, lateral bending, and axial rotation. The Cage + Plate model showed a higher increase stresses on C2 endplate and bone graft than the Cage + TARP model in all motions. CONCLUSIONS: Our results indicate that the novel Cage + Plate device may provide lower biomechanical stability than the Cage + TARP device in flexion, extension, and axial rotation, however, it may reduce stress shielding of the bone graft for successful fusion and minimize the risk of postoperative dysphagia. Clinical trials are now required to validate the reproducibility and advantages of our findings using this anchored cage for the treatment of BI with IAAD.