Arbuscular mycorrhizal fungi drive bacterial community assembly in halophyte Suaeda salsa.

Halophytes inhabit saline soils, wherein most plants cannot grow, therefore, their ecological value is outstanding. Arbuscular mycorrhizal (AM) fungi can reconstruct microbial communities to assist plants with stress tolerance. However, little information is available on the microbial community assembly of AM fungi in halophytes. A pot experiment was conducted to investigate the effects of AM fungi on rhizosphere bacterial community structure and soil physiochemical characteristics in the halophyte Suaeda salsa at 0, 100, and 400 mM NaCl. The results demonstrated that AM fungi increased soil alkaline phosphatase (ALP) activity at the three NaCl concentrations, and decreased available P, available K, and the activity of soil catalase (CAT) at 100 mM NaCl. AM fungi decreased the Shannon index of the community at 0 and 100 mM NaCl and increased Sobs index at 400 mM NaCl. Regarding the bacterial community structure, AM fungi substantially decreased the abundance of Acidobacteria phylum at 0 and 100 mM NaCl. AM fungi significantly increased the abundance of genus Ramlibacter, an oxyanion-reducing bacteria that can clean out reactive oxygen species (ROS). AM fungi recruited the genera Massilia and Arthrobacter at 0 and 100 mM NaCl, respectively. Some strains in the two genera have been ascribed to plant growth promoting bacteria (PGPB). AM fungi increased the dry weight and promoted halophyte growth at all three NaCl levels. This study supplements the understanding that AM fungi assemble rhizosphere bacterial communities in halophytes.

Bio-organic fertilizer promoted phytoremediation using native plant leymus chinensis in heavy Metal(loid)s contaminated saline soil.

Heavy metal(loid)s (HMs) contaminated saline soil appeared around the world, however, remediation regarding these collected from field conditions remains unknown. Native plants cultivation and bio-organic fertilizer (BOF) application were two efficient tools for soil amelioration. Herein, a pot experiment was conducted to examine the feasibility of a native plant (Leymus chinensis) for phytoremediation, and investigate the impacts of lignite based bio-organic fertilizer (LBOF) and manure based bio-organic fertilizer (MBOF) on phytoremediation of the soil contaminated by Pb, Cd, As, Zn, Cu, Ca2+, and SO42-. The results demonstrated the effectiveness of L. chinensis and highlighted the positive impacts of BOF according to the improved plant growth, HMs phytostabilization, salt removal, and soil properties. LBOF and MBOF changed soil microbiome to assist phytoremediation in addition to physiological modulation. Having enhanced fungal and bacterial richness respectively, LBOF and MBOF recruited various plant growth promoting rhizobacteria with different functions, and shifted microbial co-occurrence networks and keystone taxa towards these different but beneficial forms. Structural equation models comprehensively reveled the strategy discrepancy of LBOF and MBOF to regulate the plant biomass, HMs uptake, and soil salt. In summary, L. chinensis coupled with BOF, especially LBOF, was a effective strategy to remediate HMs contaminated saline soil.

Synergistic mechanisms of bioorganic fertilizer and AMF driving rhizosphere bacterial community to improve phytoremediation efficiency of multiple HMs-contaminated saline soil.

The addition of Arbuscular mycorrhizal fungi (AMF) or bioorganic fertilizer (BOF) alone has been reported to enhance plant tolerance to heavy metals and salt stress and promote plant growth, while their synergistic effects on plant growth and rhizosphere microorganism are largely unknown. This study explored the effects of AMF (Rhizophagus intraradices), BOF and BOF + RI assisted phytoremediation on heavy metals contaminated saline soil improvement and revealed the microbial mechanism. For this purpose, a pot trial consisting of four treatments (CK, RI, BOF and BOF + RI) was carried out. The results showed that the biomass, nutrient element contents, the accumulation of heavy metals and Na of Astragalus adsurgens and soil properties were most significantly improved by BOF + RI. BOF + RI significantly impacted rhizosphere microbial diversity, abundance and community composition. Chloroflexi and Patescibacteria at the phylum level and Actinomadura, Iamia, and Desulfosporosinus at the genus level were significantly enriched in BOF + RI. Network analysis revealed that BOF + RI significantly changed the keystone and enhanced complexity and interaction. Most of the keystones had roles in promoting plant growth and stress resistance. This study suggested that phytoremediation assisted by BOF and AMF is an attractive approach to ameliorate heavy metals contaminated saline soil.

Shift in rhizospheric and endophytic microbial communities of dominant plants around Sunit Alkaline Lake.

Alkaline lakes are a special type of extreme saline-alkali ecosystem, and the dominant plants store a large number of microbial resources with salinity-tolerant or growth-promoting properties in the littoral zones. In this study, high-throughput sequencing technology and molecular ecological networks were used to analyze the bacteria and fungi from different rhizocompartments of three dominant plants along the salinity gradient in the littoral zones of Sunit Alkali Lake. The study found that fungal communities were more tolerant of environmental abiotic stress, and salinity was not the main environmental factor affecting the composition of microbial communities. Mantel test analysis revealed that SOC (soil organic carbon) was the primary environmental factor affecting the rhizosphere bacterial community as well as the rhizosphere endophyte bacteria and fungi, while CO32- (carbonate ions) had a greater impact on the rhizosphere fungal communities. In addition, keystones identified through the associated molecular network play an important role in helping plants resist saline-alkali environments. There were significant differences in the metabolic pathways of microorganisms from different rhizocompartments predicted by the PICRUSt2 database, which may help to understand how microorganisms resist environmental stress. This study is of great importance for understanding the salt environments around alkaline lakes and excavating potential microbial resources.

Exploring Microbial Resource of Different Rhizocompartments of Dominant Plants Along the Salinity Gradient Around the Hypersaline Lake Ejinur.

Lake littoral zones can also be regarded as another extremely hypersaline environment due to hypersaline properties of salt lakes. In this study, high-throughput sequencing technique was used to analyze bacteria and fungi from different rhizocompartments (rhizosphere and endosphere) of four dominant plants along the salinity gradient in the littoral zones of Ejinur Salt Lake. The study found that microbial α-diversity did not increase with the decrease of salinity, indicating that salinity was not the main factor on the effect of microbial diversity. Distance-based redundancy analysis and regression analysis were used to further reveal the relationship between microorganisms from different rhizocompartments and plant species and soil physicochemical properties. Bacteria and fungi in the rhizosphere and endosphere were the most significantly affected by SO4 2-, SOC, HCO3 -, and SOC, respectively. Correlation network analysis revealed the potential role of microorganisms in different root compartments on the regulation of salt stress through synergistic and antagonistic interactions. LEfSe analysis further indicated that dominant microbial taxa in different rhizocompartments had a positive response to plants, such as Marinobacter, Palleronia, Arthrobacter, and Penicillium. This study was of great significance and practical value for understanding salt environments around salt lakes to excavate the potential microbial resources.

Two types nitrogen source supply adjusted interaction patterns of bacterial community to affect humifaction process of rice straw composting.

This study investigated effects of high-nitrogen source (urea) (R_UR) and protein-like nitrogen source (chicken manure) (R_CM) on humification process during lignocellulose biomass composting. It demonstrated that decreasing ratio of crude fiber (CF), polysaccharide (PS) and amino acids (AAs) in R_CM (29.75%, 53.93% and 73.73%, respectively) was higher than that in R_UR (14.73%, 28.74% and 51.92%, respectively). Humic substance (HS) concentration increased by 7.51% and 73.05% during R_UR and R_CM composting, respectively. The lower total links, more independent modularization and higher proportion of positive correlations between functional bacteria and organic components was observed with R_CM network than R_UR, indicating that protein-like nitrogen source supply may alleviate competition within bacterial community. Moreover, chicken manure supply favorably selects greater special functional bacterial taxa (Pusillimonas, Pedomicrobium, Romboustia and other 24 genus) related to AAs and stimulates the collaborative division of bacterial community. This is significance for strengthening effective transformation of organic components.

Evaluation of Microbial Assemblages in Various Saline-Alkaline Soils Driven by Soluble Salt Ion Components.

Land degraded by salinization and alkalization is widely distributed globally and involves a wide range of ecosystem types. However, the knowledge of the indigenous microbial assemblages and their roles in various saline-alkaline soils is limited. This study demonstrated microbial assemblages in various saline-alkaline soils from different regions of Inner Mongolia and revealed the key driving factors to influence microbiome. The correlation network analysis indicates the difference in adaptability of bacterial and fungal communities under stimulation by saline-alkaline stress: fungal community shows higher tolerance, stability, and resilience to various saline-alkaline soils than a bacterial community. The keystone bacteria and fungi that have potential adaptability to various saline-alkaline environments are further identified, and they may confer benefits in restoring saline-alkaline soils by their own effects or assisting plants. For salt-rich soils in different regions, the soluble salt ion components are the major determinant to drive microbial assemblages of different saline-alkaline soils, rather than salinity. Thus, these saline-alkaline soils are clustered into sulfated, chlorinated, and soda-type saline-alkaline soils. Multivariate analysis reveals unique, dominant, and common microbial taxa in three saline-alkaline soils. This result of the conceptual mode indicates that potential roles of unique and dominant microbial taxa on regulating saline-alkaline functions are more vital.

[Potential of Arbuscular Mycorrhizal Fungi, Biochar, and Combined Amendment on Sandy Soil Improvement Driven by Microbial Community].

Sandy soils are considered as a significant transition phase to desertification. The effective recovery of sandy soils is of great significance to mitigate the desertification process. Some studies have shown that arbuscular mycorrhizal (AM) fungi and biochar improved the sandy soil, but there have been very few studies regarding the combined effects of AM fungi and biochar amendments on sandy soil improvement. Additionally, the roles of the bacterial and fungal community during the process of sandy soil improvement remain unclear. A greenhouse pot experiment with four treatments, including a control (CK, no amendment), single AM fungi-assisted amendment (RI), single biochar amendment (BC), and combined amendment (BC_RI, biochar plus AM fungi), was set up. This study investigated the effects of different amendment methods on the Nitrariasi birica mycorrhizal colonization, biomass, nutrient (N, P, K, Ca, and Mg) content, soil organic carbon, soil nutrient (TN, TP, and TK) content, and soil water-stable aggregate composition. High throughput sequencing technology was used to investigate the roles of the bacterial and fungal communities during the process of sandy soil improvement. Combined with multiple analysis methods, the improvement mechanisms of different amendment methods were explored. The aim was to provide basic data and scientific basics for reasonably and effectively improving sandy soils. The results indicated that a significant mycorrhiza colonization was observed in the inoculation (RI and BC_RI) treatments, but there was no substantial difference in the mycorrhiza colonization with the RI and BC_RI. Compared with the CK, the shoot biomass and shoot element (N, K, Ca, and Mg) contents were significantly increased in the RI, and the shoot element (N, P, K, Ca, and Mg) contents were significantly increased in the BC and BC_RI; compared with the RI and BC, the root biomass and the root element (P, K, Ca, and Mg) contents were significantly increased in the BC_RI. Compared with the CK, the soil organic carbon contents were significantly increased in the BC and BC_RI, the soil TN contents were significantly increased by 152.54%, and the soil TP and TK contents were significantly decreased by 12.5% and 18.8%, respectively. The proportion of soil aggregates with particle sizes of 0.25-0.05 mm was the highest in each treatment, and the large particle size (>0.25 mm) soil aggregate was significantly increased in the BC_RI. Compared with the CK, the Sobs and Shannon indices of the bacterial/fungal community were significantly decreased in the RI and BC_RI. There was a difference in the microbial community compositions and abundance in the various treatments. The results of the RDA and network analysis were as follows:the effects of AM fungi, biochar, and combined amendment on the soil environment and microbial community structure were significant; in the different amendment treatments, the relationship of the microbial molecular ecological network was significantly changed, and the composition of the core species varied; compared with the RI, there was a higher network connection degree and a richer core species composition in the BC and BC_RI; moreover, the essential role of Rhizophagus intraradices was weaken and the core roles of the other microorganisms (especially bacterial species) were enhanced under the combined effects of biochar and AM fungi. The SEM results demonstrated that the application of AM fungi and biochar could directly affect the bacteria/fungi community structure, and further affect the plant growth and soil properties. The differences in the microbial community structure (especially the change in the microbial interaction) were the key driving factors that led to the difference in the soil improvement effectiveness. In summary, the effects of the different amendment methods on the improvement effectiveness of sandy soils varied. The microbial community played key roles in the process of sandy soil improvement, and there were potential advantages and applications in accelerating the ecological restoration of sandy soils under the combined AM fungi and biochar amendment.

Nucleolin down-regulation is involved in ADP-induced cell cycle arrest in S phase and cell apoptosis in vascular endothelial cells.

High concentration of extracellular ADP has been reported to induce cell apoptosis, but the molecular mechanisms remain not fully elucidated. In this study, we found by serendipity that ADP treatment of human umbilical vein endothelial cells (HUVEC) and human aortic endothelial cells (HAEC) down-regulated the protein level of nucleolin in a dose- and time-dependent manner. ADP treatment did not decrease the transcript level of nucloelin, suggesting that ADP might induce nucleolin protein degradation. HUVEC and HAEC expressed ADP receptor P2Y13 receptor, but did not express P2Y1 or P2Y12 receptors. However, P2Y1, 12, 13 receptor antagonists MRS2179, PSB0739, MRS2211 did not inhibit ADP-induced down-regulation of nucleolin. Moreover, MRS2211 itself down-regulated nucleolin protein level. In addition, 2-MeSADP, an agonist for P2Y1, 12 and 13 receptors, did not down-regulate nucleolin protein. These results suggested that ADP-induced nucleolin down-regulation was not due to the activation of P2Y1, 12, or 13 receptors. We also found that ADP treatment induced cell cycle arrest in S phase, cell apoptosis and cell proliferation inhibition via nucleolin down-regulation. The over-expression of nucleolin by gene transfer partly reversed ADP-induced cell cycle arrest, cell apoptosis and cell proliferation inhibition. Furthermore, ADP sensitized HUVEC to cisplatin-induced cell death by the down-regulation of Bcl-2 expression. Taken together, we found, for the first time to our knowledge, a novel mechanism by which ADP regulates cell proliferation by induction of cell cycle arrest and cell apoptosis via targeting nucelolin.

[Relationship between levels of antibody to schistosome of armed police officers and soldiers and their camp environment].

OBJECTIVE: To understand the schistosome infection status of armed police officers and soldiers in endemic areas of the middle and lower reaches of the Yangtze River and the impact caused by the camp environment. METHODS: The inside and outside environments of camps were investigated and they were classified as Grade A, B and C according to scores. The levels of antibody to schistosome of the armed police officers and soldiers were tested with ELISA. RESULTS: A total of 23 780 officers and soldiers in 201 camps were investigated. The positive rates of antibody to schistosome of officers and soldiers stationed in the inner embankment areas, river beach areas and island areas were 1.88%, 3.89% and 4.73%, respectively. In the aforementioned three types areas, the positive rates of antibody to schistosome of soldiers and officers in the camp environment scored as Grade A were 1.23%, 3.28% and 3.33%, respectively, while the positive rates in the environment scored as Grade B were 2.03%, 3.81% and 4.24%, respectively, and the positive rates in the environment scored as Grade C were 3.17%, 5.79% and 5.83%, respectively. CONCLUSIONS: There are certain correlation between the prevalence of schistosomiasis in armed police forces and the internal and external environments of their camps. The comprehensive environment management is one of the key measures of schistosomiasis control for armed police forces.

[Endemic situation and control strategies on schistosomiasis in Armed Police Forces in marshland and lake regions].

OBJECTIVE: To investigate the prevalence of schistosomiasis in Armed Police Forces in marshland and lake regions so as to provide the evidence for policy-making of the disease control. METHODS: The different types of duty were selected by the stratified cluster random sampling method in endemic areas of marshland and lake regions, and the snail survey was conducted, and the infectious status and epidemic factors of officers and soldiers who served more than 2 years were investigated. RESULTS: The geographical features included the embankment type, island type and islet type, and the serological positive rates were 1.88%, 4.73% and 3.89% in the 3 types of endemic areas respectively and he total positive rate was 3.10%, that was lower than the national population level in 2009. The infection risk factors included fighting flood, and the contact with infested water in daily life and production. CONCLUSIONS: We should strengthen the surveillance and control of schistosomiasis in this particular group of officers and soldiers, especially in their implementation of fighting flood and other tasks.