82 research outputs found
Microbial resistance promotes plant production in a four-decade nutrient fertilization experiment
Get PDFThere is a current lack of mechanistic understanding on the relationships between a soil microbial community, crop production, and nutrient fertilization. Here, we combined ecological network theory with ecological resistance index to evaluate the responses of microbial community to additions of multiple inorganic and organic fertilizers, and their associations with wheat production in a 35-year field experiment. We found that microbial phylotypes were grouped into four major ecological clusters, which contained a certain proportions of fast-growers, copiotrophic groups, and potential plant pathogens. The application of combined inorganic fertilizers and cow manure led to the most resistant (less responsive) microbial community, which was associated with the highest levels of plant production, nutrient availability, and the lowest relative abundance of potential fungal plant pathogens after 35 years of nutrient fertilization. In contrast, microbial community was highly responsive (low resistance) to inorganic fertilization alone or plus wheat straw, which was associated with lower crop production, nutrient availability, and higher abundance of potential fungal plant pathogens. Our work demonstrates that the response of microbial community to long-term nutrient fertilizations largely regulates plant production in agricultural ecosystems, and suggests that manipulating these microbial phylotypes may offer a sustainable solution to the maintenance of field productivity under long-term nutrient fertilization scenarios. © 2019 The Author
Effectiveness of existing legal and regulatory framework under study visa site - Comparative analysis of jurisprudence based
No full textEcological relevance of flagellar motility in soil bacterial communities
No full textFlagellar motility is a key bacterial trait as it allows bacteria to navigate their immediate surroundings. Not all bacteria are capable of flagellar motility, and the distribution of this trait, its ecological associations, and the life history strategies of flagellated taxa remain poorly characterized. We developed and validated a genome-based approach to infer the potential for flagellar motility across 12 bacterial phyla (26 192 unique genomes). The capacity for flagellar motility was associated with a higher prevalence of genes for carbohydrate metabolism and higher maximum potential growth rates, suggesting that flagellar motility is more prevalent in environments with higher carbon availability. To test this hypothesis, we applied a method to infer the prevalence of flagellar motility in whole bacterial communities from metagenomic data and quantified the prevalence of flagellar motility across four independent field studies that each captured putative gradients in soil carbon availability (148 metagenomes). We observed a positive relationship between the prevalence of bacterial flagellar motility and soil carbon availability in all datasets. Since soil carbon availability is often correlated with other factors that could influence the prevalence of flagellar motility, we validated these observations using metagenomic data from a soil incubation experiment where carbon availability was directly manipulated with glucose amendments. This confirmed that the prevalence of bacterial flagellar motility is consistently associated with soil carbon availability over other potential confounding factors. This work highlights the value of combining predictive genomic and metagenomic approaches to expand our understanding of microbial phenotypic traits and reveal their general environmental associations.J.R. acknowledges funding from the Swiss National Science Foundation (Early PostDoc Mobility grant P2EZP3_199849). Funding was also provided by a grant from the US National Science Foundation awarded to N.F. and M.S.S. (award # 2131837).Peer reviewe
Biodiversity of key-stone phylotypes determines crop production in a 4-decade fertilization experiment
No full textCropping systems have fertilized soils for decades with undetermined consequences for the productivity and functioning of terrestrial ecosystems. One of the critical unknowns is the role of soil biodiversity in controlling crop production after decades of fertilization. This knowledge gap limits our capacity to assess how changes in soil biodiversity could alter crop production and soil health in changing environments. Here, we used multitrophic ecological networks to investigate the importance of soil biodiversity, in particular, the biodiversity of key-stone taxa in controlling soil functioning and wheat production in a 35-year field fertilization experiment. We found strong and positive associations between soil functional genes, crop production and the biodiversity of key-stone phylotypes; soils supporting a larger number of key-stone nematode, bacteria and fungi phylotypes yielded the highest wheat production. These key-stone phylotypes were also positively associated with plant growth (phototrophic bacteria, nitrogen fixers) and multiple functional genes related to nutrient cycling. The retrieved information on the genomes clustered with key-stone bacterial phylotypes indicated that the key-stone taxa had higher gene copies of oxidoreductases (participating most biogeochemical cycles of ecosystems and linking to microbial energetics) and 71 essential functional genes associated with carbon, nitrogen, phosphorus, and sulfur cycling. Altogether, our work highlights the fundamental role of the biodiversity of key-stone phylotypes in maintaining soil functioning and crop production after several decades of fertilization, and provides a list of key-stone phylotypes linking to crop production and soil nutrient cycling, which could give science-based guidance for sustainable food production
Soil biodiversity supports the delivery of multiple ecosystem functions in urban greenspaces
No full textThis excel file includs soil biodiversity across biomes, plant diversity, and the microbial functional traits, and also includs multiple ecosystem functions.</p
Effects of Process Parameters on the Mechanical Properties and Microstructure of Additively Manufactured Carbon Black Particles-Reinforced Thermoplastic Polyurethane Composite Samples
No full textAdditive manufacturing (AM) techniques make fabricating complex designs, prototypes, and end-user products possible. Conductive polymer composites find applications in flexible electronics, sensor fabrication, and electrical circuits. In this study, thermoplastic polyurethane (TPU)-based conductive polymer composite samples were fabricated via fused filament fabrication (FFF). The effects of three important process parameters, including infill density (ID), layer thickness (LT), and fan speed (FS), on various mechanical properties (tensile and compressive properties) were investigated. It was observed that all the considered process parameters affect the mechanical properties, and they are significant parameters, as per the analysis of variance (ANOVA). From scanning electron microscopy (SEM) and optical microscopy, various combinations of parameters such as low ID, high LT, and high FS resulted in the formation of defects such as voids, cracks, and warping, which resulted in low mechanical properties. Finally, process parameter optimization was performed, resulting in a conductive polymer composite with the best possible combination of mechanical properties at high ID, low LT, and medium FS.This work was supported by Researchers Supporting Project Number (RSP2025R274), King Saud University, Riyadh, Saudi Arabia.King Saud Universit
Wheat rhizosphere harbors a less complex and more stable microbial co-occurrence pattern than bulk soil
Get PDF© The Author(s), 2018. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Soil Biology and Biochemistry 125 (2018): 251-260, doi:10.1016/j.soilbio.2018.07.022.The rhizosphere harbors complex microbial communities, whose dynamic associations
are considered critical for plant growth and health but remain poorly understood. We
constructed co-occurrence networks for archaeal, bacterial and fungal communities
associated with the rhizosphere and bulk soil of wheat fields on the North China Plain.
Rhizosphere co-occurrence networks had fewer nodes, edges, modules and lower
density, but maintained more robust structure compared with bulk soil, suggesting that
a less complex topology and more stable co-occurrence pattern is a feature for wheat
rhizosphere. Bacterial and fungal communities followed a power-law distribution,
while the archaeal community did not. Soil pH and microbial diversity were
significantly correlated with network size and connectivity in both rhizosphere and bulk
soils. Keystone species that played essential roles in network structure were predicted
to maintain a flexible generalist metabolism, and had fewer significant correlations with
environmental variables, especially in the rhizosphere. These results indicate that
distinct microbial co-occurrence patterns exist in wheat rhizosphere, which could be
associated with variable agricultural ecosystem properties.This work was funded by the Strategic Priority Research Program of the
Chinese Academy of Sciences (XDB15010101) and the National Program on Key
Basic Research Project (2014CB954002).2020-07-2
Positive associations fuel soil biodiversity and ecological networks worldwide
Get PDF10 páginas.- 4 figuras.- 60 referencias.- This article contains supporting information online at
https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2308769121/-/DCSupplemental.-- Copyright © 2024 the Author(s). Published by PNAS. This article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND)Microbial interactions are key to maintaining soil biodiversity. However, whether negative or positive associations govern the soil microbial system at a global scale remains virtually unknown, limiting our understanding of how microbes interact to support soil biodiversity and functions. Here, we explored ecological networks among multitrophic soil organisms involving bacteria, protists, fungi, and invertebrates in a global soil survey across 20 regions of the planet and found that positive associations among both pairs and triads of soil taxa governed global soil microbial networks. We further revealed that soil networks with greater levels of positive associations supported larger soil biodiversity and resulted in lower network fragility to withstand potential perturbations of species losses. Our study provides unique evidence of the widespread positive associations between soil organisms and their crucial role in maintaining the multitrophic structure of soil biodiversity worldwide.This work was funded by a Large Research Grant from the British Ecological Society (No. LRB17\1019; MUSGONET). H.C. was supported by the National Key R&D Program of China (2022YFD1500202), the Strategic Priority Research Program of Chinese Academy of Sciences (XDA28020202), the National Natural Science Foundation of China (42230511, 92251305), and the Second Tibetan Plateau Scientific Expedition and Research Program (STEP, 2019QZKK0503). M.D.-B. acknowledges support from the Spanish Ministry of Science and Innovation for the I+D+i project PID2020-115813RA-I00 funded by MCIN/AEI/10.13039/501100011033. M.D.-B. was also supported by a project of the Fondo Europeo de Desarrollo Regional (FEDER) and the Consejería de Transformación Económica, Industria, Conocimiento y Universidades of the Junta de Andalucía (FEDER Andalucía 2014-2020 Objetivo temático “01—Refuerzo de la investigación, el desarrollo tecnológico y la innovación”) associated with the research project P20_00879 (ANDABIOMA). O.G. acknowledges financial support provided by the Spanish Ministry of Economy and Competitiveness and by the European Social Fund through a Ramón y Cajal contract (RyC 2017-23666).Peer reviewe
Soil Biodiversity Supports The Delivery Of Multiple Ecosystem Functions In Urban Greenspaces
No full textRisk factors of recurrence for resected T1aN0M0 invasive lung adenocarcinoma: a clinicopathologic study of 177 patients
No full textBackground: This study aimed at identifying risk factors of recurrence for completely resected pathologic T1aN0M0 lung adenocarcinomas. Methods: We reviewed the records of 177 T1aN0M0 invasive adenocarcinoma patients, and re-classified achieved surgical specimens according to the new International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society (IASLC/ATS/ERS) lung adenocarcinoma classification. Impact on recurrence-free survival (RFS) for age, gender, smoking history, lymphovascular invasion (LVI) and new classification was analyzed by log-rank test and Cox regression. Two existing prognostic grouping schemes of new classification were compared, and subsequently, the correlation of high-grade group in the better prognostic grouping model with clinical data was investigated statistically. Results: The 5-year recurrence-free rate was 83.7%. The LVI and new adenocarcinoma classification were significantly associated with 5-year RFS (P = 0.012; P = 0.022, respectively). The designation of papillary predominant subtype in the low-grade group, along with lepidic-and acinar predominant subtype had more prognostic significance than the model of combining papillary-, solid- and micropapillary predominant subtypes as the high-grade group (P = 0.005 versus P = 0.181). This high-grade group has increased risk of recurrence in a multivariate Cox regression (adjusted HR 2.815, 95% CI: 1.239 to 6.397, P = 0.013), and is associated significantly more with male gender (adjusted OR 2.214, 95% CI: 1.050 to 4.668, P = 0.037), and, with borderline significance, the presence of LVI (adjusted OR 2.091, 95% CI: 0.938 to 4.662, P = 0.071). Conclusions: Our results showed that the solid-and micropapillary predominant subtype of IASLC/ATS/ERS classification remains the only risk factor for post-operative recurrence of T1aN0M0 adenocarcinomas, suggesting that they can be indicators of aggressive tumor behaviors.OncologySurgerySCI(E)PubMed中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)[email protected]
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