Exotic plantations differ in "nursing" an understory invader: A probe into invasional meltdown.

Forest plantations most likely promote exotic plant invasion. Using an in situ monitoring method, this study investigated the traits correlated with growth and reproduction of an understory invader, Phytolacca americana L., and ecological factors including understory irradiance, soil stoichiometry and microbial patterns associated with these traits in different exotic plantations of Robinia pseudoacacia L. and Pinus thunbergii Parl. at Mount Lao, Qingdao, China. We found that the traits of P. americana underneath the R. pseudoacacia stand might be situated at the fast side of the trait economic spectrum. The R. pseudoacacia stand appeared to "nurse" P. americana. Furthermore, we intended to explain the nurse effects of R. pseudoacacia stands by examining their ecological factors. First, the R. pseudoacacia stand created understory light attenuation, which matched the sciophilous feature of P. americana. Second, the soil beneath the R. pseudoacacia stand might benefit P. americana more since the soil has greater resource availability. Third, a higher microbial diversity was found in the soil derived from P. americana underneath the R. pseudoacacia stand. A greater abundance of plant pathogens was detected in the soil derived from P. americana in the R. pseudoacacia stand, while more abundant mycorrhizal fungi were detected in the P. thunbergii stand. We speculate that plant pathogens can defend P. americana from aggression from other understory competitors. The mycorrhizal fungi in the P. thunbergii stand might benefit P. americana while simultaneously benefiting other understory plants. Intensive competition from other plants might interfere with P. americana. The potential relationships between plant performance and ecological factors may explain the invasion mechanism of P. americana. The present study provides a novel insight on the facilitative effects of exotic tree plantation on an exotic herb through the modification of soil biota, with implications for the biocontrol of invasive species and forest management and conservation.

Nutrient stoichiometric and resorption characteristics of the petals of four common urban greening Rosaceae tree species.

Objective: Nutrient resorption efficiency and stoichiometric ratios are important strategies for understanding plants. The present study examined whether or not the nutrient resorption process of plant petals is similar to that of leaves and other vegetative organs, as well as the nutrient restriction status of the whole flowering process of plants in urban ecosystems. Methods: Four Rosaceae tree species, Prunus yedoensis Matsum, Prunus serrulata var. lannesiana, Malus micromalus Makino, and Prunus cerasifera 'Atropurpurea', were selected as urban greening species to analyze the contents of C, N, P, and K elements in the petals and their stoichiometric ratios and nutrient resorption efficiencies. Results: The results show interspecific differences in nutrient contents, stoichiometric ratios, and nutrient resorption efficiency of the fresh petals and petal litter of the four Rosaceae species. The nutrient resorption process was similar to that of the leaves before the petals fell. The nutrient contents of petals were higher than that of leaves at the global level, but the stoichiometric ratio and nutrient resorption efficiency of petals were lower. According to the "relative resorption hypothesis", N was limiting during the entire flowering period. The nutrient resorption efficiency of petals was positively correlated with nutrient variation. The correlation between the nutrient resorption efficiency of petals with nutrient content and stoichiometric ratio of petal litter was stronger. Conclusion: The experimental results provide scientific basis and theoretical support for the selection, scientific maintenance and fertilization management of Rosaceae tree species in urban greening.

Diversity and assembly of root-associated microbiomes of rubber trees.

Introduction: Understanding the diversity and assembly of the microbiomes of plant roots is crucial to manipulate them for sustainable ecosystem functioning. However, there are few reports about microbial communities at a continuous fine-scale of roots for rubber trees. Methods: We investigate the structure, diversity, and assembly of bacterial and fungal communities for the soil (non-rhizosphere), rhizosphere, and rhizoplane as well as root endosphere of rubber trees using the amplicon sequencing of 16S ribosomal ribonucleic acid (rRNA) and Internally Transcribed Spacer (ITS) genes. Results: We show that 18.69% of bacterial and 20.20% of fungal operational taxonomic units (OTUs) in the rhizoplane derived from the endosphere and 20.64% of bacterial and 20.60% of fungal OTUs from the soil. This suggests that the rhizoplane microbial community was a mixed community of soil and endosphere microbial communities and that microorganisms can disperse bidirectionally across different compartments of the plant root. On the other hand, in the absence of an enrichment or depletion of core bacterial and fungal OTUs in the rhizosphere, little differences in microbial composition as well as a more shared microbial network structure between the soil and the rhizosphere support the theory that the rhizosphere microbial community is a subset of the soil community. A large number of functional genes (such as nitrogen fixation and nitrite reduction) and more enriched core OTUs as well as a less stable but more complex network structure were observed in the rhizoplane of rubber tree roots. This demonstrated that the rhizoplane is the most active root compartment and a hotspot for plant-soil-environment interactions. In addition, bacterial and fungal communities in the rhizoplane were more stochastic compared to the rhizosphere and soil. Discussion: Our study expands our understanding of root-associated microbial community structure and function, which may provide the scientific basis for sustainable agriculture through biological process management.

[Clinical Study of miRNAs Derived from Serum Exosomes in Multiple Myeloma].

OBJECTIVE: To investigate the expression level and prognostic value of miR-21, miR-18a, miR-146a, and Let-7b derived from serum exosomes in patients with multiple myeloma (MM). METHODS: Serum exosomes were extracted from 57 MM patients and 20 healthy persons using ExoQuick exosome precipitation solution kit, and the relative expression level of miR-21, miR-18a, miR-146a, and Let-7b derived from serum exosomes was measured by RT-qPCR. Correlations of the expression levels of all miRNAs mentioned above with routine laboratory parameters were analyzed by Spearman correlation analysis. The relationship between the expression level of miR-21, miR-18a, miR-146a, and Let-7b derived from serum exosomes and overall survival of patients with MM was analyzed using the Kaplan-Meier survival curve. RESULTS: The expression levels of miR-21, miR-18a, and Let-7b derived from serum exosomes in patients with MM were significantly lower than those in the normal control group (P<0.001), while the expression level of miR-146a between the two groups was not significantly different (P>0.05). The expression level of miR-21 was strongly negatively correlated with serum ß2-microglobulin concentration (r=-0.830), and weakly negatively correlated with serum creatinine, corrected serum calcium, and cystatin C (r=-0.488, -0.282, -0.627). The expression levels of Let-7b and miR-18a were also weakly negatively correlated with the corrected serum calcium, ß2-microglobulin, and cystatin C concentration (r=-0.305, -0.362, -0.461; -0.317, -0.542, -0.434). However, there was no significant correlation between the expression level of miR-146a and routine laboratory parameters in MM patients. The overall survival rate of MM patients with low expression level of miR-21, miR-18a, and Let-7b significantly decreased compared with high expression level group (P<0.05), however, the expression level of miR-146a was not related to the overall survival rate. CONCLUSION: Aberrant low expression levels of miR-21, miR-18a, and Let-7b derived from serum exosomes exist in patients with MM, which are associated with a worse overall survival rate.

m6A-Related lncRNA to Develop Prognostic Signature and Predict the Immune Landscape in Bladder Cancer.

Abnormal m6A methylation plays a significant role in cancer progression. Increasingly, researchers have focused on developing lncRNA signatures to evaluate the prognosis of cancer patients. The specific function of m6A-related lncRNAs in the prognosis of bladder cancer patients and the immune microenvironment of bladder cancer remains elusive. Herein, we performed a comprehensive analysis of m6A-related lncRNA prognostic values and their association with the immune microenvironment in bladder cancer using the TCGA dataset. A total of 9 m6A-related lncRNAs were dramatically correlated with overall survival outcomes in bladder cancer. Two molecular subtypes (cluster 1 and cluster 2) were identified by consensus clustering for 9 m6A-related prognostic lncRNAs. Cluster 1 was significantly correlated with poor prognosis, advanced clinical stage, higher PD-L1 expression, a higher ESTIMATEScore and immuneScore, and distinct immune cell infiltration. GSEA revealed the enrichment of apoptosis and the JAK-STAT signaling pathway in cluster 2. A prognostic risk score was constructed using 9 m6A-related prognostic lncRNAs, which functioned as an independent prognostic factor for bladder cancer. Moreover, bladder cancer patients in the low-risk score group had a higher pN stage, pT stage, and clinical stage and a lower tumor grade and immuneScore. The risk score was correlated with the infiltration levels of certain immune cells, including B cells, plasma cells, follicular helper T cells, regulatory T cells, resting NK cells, neutrophils, M0 macrophages, M1 macrophages, and M2 macrophages. Collectively, our study elucidated the important role of m6A-related lncRNAs in the prognosis of bladder cancer patients and in the bladder cancer immune microenvironment. The results suggest that the components of the m6A-related prognostic lncRNA signature might serve as a crucial mediator of the immune microenvironment in bladder cancer, representing promising therapeutic targets for improving immunotherapeutic efficacy.

Prevalence and genotype distribution of high-risk human papillomavirus in 34 420 cases in Yangzhou city, Jiangsu province, China.

We aimed to study the infection status and distribution of human papillomavirus (HPV) in Yangzhou City to provide precise guidance for the prevention and treatment of cervical cancer in this area. Reproductive tract secretions were collected from patients admitted at Subei People's Hospital over the past 3 years. Fifteen high-risk HPV (HR-HPV) genotypes were analyzed by fluorescent polymerase chain reaction. The positive rate of HR-HPV in 34 420 subjects was 23.56%. There was no significant difference in the rate of overall infection between males and females (χ 2 = 0.04; p = 0.952 > 0.05). The five genotypes with high infection rates in the population were HPV52, HPV58, HPV16, HPV51, and HPV39. Single infection was found to be dominant, primarily with the HPV52 genotype. The infection rate was higher in patients less than 20 years old and more than 60 years old. Most patients with cervical intraepithelial neoplasms 2/3 and cervical cancer were infected by HPV16, followed by those infected by HPV52 and HPV58. There was a significant difference in the infection rate of HPV16 among patients with different cervical lesions (χ 2 = 31.660; p < 0.01), and the infection rate of HPV16 was higher in patients with cervical cancer than in healthy individuals. Single infection was dominant among the study patients with HPV infection in Yangzhou city. There was no significant difference in infection rate and genotype distribution between males and females. The infection rate in young and old women was higher, and the rate increased with age (>20 years).

Mining therapeutic and prognostic significance of STATs in renal cell carcinoma with bioinformatics analysis.

Renal cell carcinoma is one of the most common malignancies with high morbidity and mortality. STAT proteins play a significant role in cell biological behavior and immune response associated with cancer progression. In our study, the datasets analyzed for the expression and potential functions can be found in several bioinformatics analysis tools. We found that STAT1/2/4/6 were upregulated in RCC while STAT3/5B were downregulated. The expression of STAT2/4/5B were significantly associated with the pathological stage of RCC patients. RCC patients with high expression of STAT2/4 and low/medium expression of STAT5B had a poor overall survival. The function of STATs and the neighboring genes mainly enriched in JAK-STAT signaling pathway and NOD-like receptor signaling pathway. Several transcription factor, kinase, and miRNA targets were identified. Close correlations were obtained between immune cell infiltration and STATs in RCC. Our results have provided novel insights for the selection of immunotherapeutic targets and prognostic biomarkers.

Seasonal changes impact soil bacterial communities in a rubber plantation on Hainan Island, China.

Rubber plantations have expanded rapidly over the past 20 years in tropical Asia and their impacts on regional ecosystems have garnered much concern. While much attention has been given to the negative impacts on aboveground diversity and function, the belowground bacterial soil community has received much less attention. Here, we investigated the community composition and diversity of soil bacteria of rubber plantations on Hainan Island in south China. The goals of the study were to describe changes in bacterial compositions and diversity across seasons. We found that seasonality defined by differences in rainfall amount strongly influenced bacterial communities. At both the Phylum and Family levels, we found significant differences in the total number of taxa, as well as the composition of the community as a function of season. Diversity of soil samples in the dry-rainy season was highest of three seasons, suggesting that bacterial structure was more sensitive in alternate periods of season. Diversity in the rainy season was substantial lower than in dry season. Results from a redundancy analysis showed that seasonal changes explained the largest part (31.9%) of the total variance of bacterial community composition. In conclusion, seasonal change had the greatest influence on bacterial communities, which overshadowed the effects of soil nutrient as well as other factors, and controls the bacterial communities in soils of RP in tropical region of Hainan.

Rubber Trees Demonstrate a Clear Retranslocation Under Seasonal Drought and Cold Stresses.

Having been introduced to the northern edge of Asian tropics, the rubber tree (Hevea brasiliensis) has become deciduous in this climate with seasonal drought and cold stresses. To determine its internal nutrient strategy during leaf senescence and deciduous periods, we investigated mature leaf and senescent leaf nutrients, water-soluble soil nutrients and characteristics of soil microbiota in nine different ages of monoculture rubber plantations. Rubber trees demonstrate complicated retranslocation of N, P, and K during foliar turnover. Approximately 50.26% of leaf nutrients and 21.47% of soil nutrients were redistributed to the rubber tree body during the leaf senescence and withering stages. However, no significant changes in the structure- or function-related properties of soil microbes were detected. These nutrient retranslocation strategy may be important stress responses. In the nutrient retranslocation process, soil plays a dual role as nutrient supplier and nutrient "bank." Soil received the nutrients from abscised leaves, and also supplied nutrients to trees in the non-growth stage. Nutrient absorption and accumulation began before the leaves started to wither and fall.

Source apportionment of polycyclic aromatic hydrocarbons in soils of Huanghuai Plain, China: comparison of three receptor models.

Receptor models are useful tools to identify sources of a specific pollutant and to estimate the quantitative contributions of each source based on environmental data. This paper reports on similarities and differences in results achieved when testing three receptor models for estimating the sources of polycyclic aromatic hydrocarbons (PAHs) in soils from Huanghuai Plain, China. The three tested models are Principal Component Analysis with Multiple Linear Regression (PCA-MLR), Positive Matrix Factorization (PMF) and Unmix. Overall source contributions as well as modeled ∑PAHs concentrations compared well among models. All three models apportioned three common PAH sources: wood/biomass burning, fossil fuel combustion and traffic emission, which contributed on average 27.7%, 53.0% and 19.3% by PCA-MLR, 36.9%, 27.2% and 16.3% by PMF, and 47.8%, 21.1% and 18.3% by Unmix to the total sum of PAHs (∑PAHs), respectively. Moreover, the spatial evolution of the common sources were well correlated among models (r=0.83-0.99, p<0.001). In addition, the PMF and Unmix models allowed segregating an additional source from the fossil fuel combustion source, with 19.6% and 11.8% contributions to ∑PAHs, respectively. The current findings further validate that different receptor models provide divergent source profiles, which are mainly attributed to both the model itself and/or the underlying dataset. It is therefore generally recommended to apply multiple techniques to determine the source apportionment in order to minimize individual-method weaknesses and thereby to strengthen the conclusion.

Mixed polybrominated/chlorinated dibenzo-p-dioxins and dibenzofurans in stack gas emissions from industrial thermal processes.

Very little is known about mixed polybrominated/chlorinated dibenzo-p-dioxins and dibenzofurans (PBCDD/F) in industrial thermal processes. In this study, the occurrences and characteristics of PBCDD/F from various incineration and metallurgical processes were investigated. In addition, PBCDD/F analytical protocols based on HRGC/HRMS were developed and optimized. The sum of isomer group concentrations ranged from 1.7-3740 pmol Nm(-3) for PBCDF and 0.2-582 pmol Nm(-3) for PBCDD. For some metallurgical industries, the amounts of PBDD/F and PBCDD/F emitted were similar to or even higher than the amounts of PCDD/F. The sources of bromine and brominated-precursors in these processes should be evaluated. The PBCDD/F characteristics investigated included isomer group patterns, ratio of bromine and chlorine incorporated in PBCDD/F, and ratio of halogenated furans to dioxins. Lower brominated PBCDD/F were binomially distributed. But in some cases, the concentrations of higher brominated PBCDD/F were much higher than predicted from the binomial distribution. The formation mechanisms of PBDD/F, PBCDD/F, and PCDD/F in these processes were also evaluated.

Occurrence and characteristics of polybrominated dibenzo-p-dioxins and dibenzofurans in stack gas emissions from industrial thermal processes.

The occurrence and characteristics of 2,3,7,8-substituted polybrominated and polychlorinated dibenzo-p-dioxins and dibenzofurans (PBDD/F and PCDD/F) from various combustion and metallurgic industrial thermal processes were investigated. PBDD/F levels from metallurgic processes (TEQ) concentrations from 0.14 to 1.5 ng Nm(-3), mass concentrations from 0.56 to 5.8 ng Nm(-3)) were markedly higher than those from combustion processes (TEQ) concentrations from 0.010 to 0.054 ng Nm(-3), mass concentrations from 0.025 to 0.15 ng Nm(-3)). This indicated that metallurgic processes could be important sources of PBDD/F. Consequently, more attention should be paid to the metallurgical emission sources in addition to combustion of brominated flame retardants (BFRs) and related products. Specific isomeric patterns for PCDD/F from various industrial sources were highly consistent, while PBDD/F patterns were not. This revealed that PCDD/F might form through a common mechanism such as de novo synthesis mechanism, while PBDD/F might form by different mechanisms in thermal processes such as precursor mechanisms. Finally, an approach to identify the PBDD/F sources in ambient air by using the PBDD/F to PCDD/F ratio was developed.

[Source apportionment of aerosol lead in Beijing using absolute principal component analysis].

From 18 September 2005 to 13 September 2006 in Beijing, 166 TSP samples were collected at three sites in southern suburb, downtown and northern suburb, respectively. Lead and other 28 elements were determined for those samples by ICP-AES and ICP-MS methods. The lead average concentration of one year in southern suburb, downtown and northern suburb was 179, 142 and 102 ng x m(-3), respectively. Source identification and apportionment were carried out using absolute principal component analysis (APCA) method. Five groups of sources were recognized. The sources are nonferrous metallurgy (55.6%), coal combustion (16.9%), construction dust (11.8%) and soil dust (10.2%), respectively. Major sources of aerosol lead in Beijing were from nonferrous metallurgy industry. Lead associated with coal combustion and other sources were evenly distributed over three sites. However, industrial leadwas apparently at different levels at three sites, higher in southern suburb and lower in northern suburb. The lead concentration originated from nonferrous metallurgy at three sites from southern suburb, downtown to northern suburb was 113, 77.0 and 44.2 ng x m(-3), respectively, implying that the major sources for industrial lead were from the south to the Beijing. There is considerable space for reduction of aerosol lead concentration in Beijing. The main object for lead pollution discharge reduction and environmental management measures should aim at nonferrous metallurgy, especially for the field of lead metallurgy located at the south area to the Beijing. The calculation result based on the same chemical analysis data also shows that major source for TSP in Beijing is of soil dust and construction dust, accounting for 72.3%. The other sources such as coal combustion and nonferrous metallurgy account for 13.4% and 9.5%, respectively.