A point-of-care testing platform for on-site identification of genetically modified crops.

Genetically modified (GM) food is still highly controversial nowadays. Due to the disparate policies and attitudes worldwide, demands for a rapid, cost-effective and user-friendly GM crop identification method are increasingly significant for import administration, market supervision, etc. However, as the most-recognized methods, nucleic acid-based identification approaches require bulky instruments, long turn-around times and trained personnel, which are only suitable in laboratories. To fulfil the urgent needs of on-site testing, we develop a point-of-care testing platform that is able to identify 12 types of GM crops in less than 40 minutes without using laboratory settings. Our system integrates sample pre-treatment modules in a microfluidic chip, performs DNA amplification via a battery-powered portable kit, and presents results via eye-recognized colorimetric change. A paraffin-based reflow method and a slip plate-based fluid switch are developed to encapsulate and release amplification primers in individual microwells on demand, thus enabling identification of varied targets simultaneously. Our system offers an efficient, affordable and convenient tool for GM crop identification, thus it will not only benefit customs and market administration bureaus, but also satisfy demands of numerous consumers.

Global insights into endophytic bacterial communities of terrestrial plants: Exploring the potential applications of endophytic microbiota in sustainable agriculture.

Endophytic microorganisms are indispensable symbionts during plant growth and development and often serve functions such as growth promotion and stress resistance in plants. Therefore, an increasing number of researchers have applied endophytes for multifaceted phytoremediation (e.g., organic pollutants and heavy metals) in recent years. With the availability of next-generation sequencing technologies, an increasing number of studies have shifted the focus from culturable bacteria to total communities. However, information on the composition, structure, and function of bacterial endophytic communities is still not widely synthesized. To explore the general patterns of variation in bacterial communities between plant niches, we reanalyzed data from 1499 samples in 30 individual studies from different continents and provided comprehensive insights. A group of bacterial genera were commonly found in most plant roots and shoots. Our analysis revealed distinct variations in the diversity, composition, structure, and function of endophytic bacterial communities between plant roots and shoots. These variations underscore the sophisticated mechanisms by which plants engage with their endophytic microbiota, optimizing these interactions to bolster growth, health, and resilience against stress. Highlighting the strategic role of endophytic bacteria in promoting sustainable agricultural practices and environmental stewardship, our study not only offers global insights into the endophytic bacterial communities of terrestrial plants but also underscores the untapped potential of these communities as invaluable resources for future research.

Deciphering Biotic and Abiotic Mechanisms Underlying Straw Decomposition and Soil Organic Carbon Priming in Agriculture Soils Receiving Long-Term Fertilizers.

Straw-related carbon (C) dynamics are central for C accrual in agro-ecosystems and should be assessed by investigating their decomposition and soil organic carbon (SOC) priming effects. Our understanding of biotic and abiotic mechanisms underpinning these two C processes, however, is still not sufficiently profound. Soils that had received organic and mineral fertilizers for 26 years were sampled for a 28 day incubation experiment to assess 13C-labeled straw decomposition and SOC priming effects. On the basis of analyzing physicochemical properties, fungal taxonomic (MiSeq sequencing) and functional (metagenomics) guilds, we quantified the contributions of biotic and abiotic attributes to straw decomposition and SOC priming. Here, we propose two distinct mechanisms underlying straw decomposition and SOC priming in agriculture soils: (i) accelerated straw mineralization in manure-treated soils was mainly driven by biotic forces, while (ii) larger SOC priming in NPK-amended soils was through abiotic regulation.

Effects of intercropping on safe agricultural production and phytoremediation of heavy metal-contaminated soils.

Intercropping with hyperaccumulators is believed to be an important and efficient way to achieve simultaneous safe agricultural production and phytoremediation of polluted soils. However, some studies have suggested that this technique might facilitate the uptake of heavy metals by crops. To investigate the effects of intercropping on the heavy metal contents of plants and soil, data from 135 global studies were collected and analyzed by meta-analysis. The results showed that intercropping could significantly reduce the contents of heavy metals in the main plants and soils. Plant species was the main factor that affected plant and soil metal contents in the intercropping system, and the heavy metal content could be significantly reduced when members of the Poaceae and Crassulaceae were used as main plants or when legumes were used as intercropped plants. Among all the intercropped plants, the best one for removing heavy metals from the soil was a Crassulaceae hyperaccumulator. These results not only highlight the main factors affecting intercropping systems but also provide reliable reference information for the practice of safe agricultural production coupled with phytoremediation of heavy metal-contaminated farmland.

Cadmium phytoextraction through Brassica juncea L. under different consortia of plant growth-promoting bacteria from different ecological niches.

Combined bioaugmentation inoculants composed of two or more plant growth-promoting bacteria (PGPB) were more effective than single inoculants for plant growth and cadmium (Cd) removal in contaminated soils. However, the principles of consortia construction still need to be discovered. Here, a pot experiment with Cd natural polluted soil was conducted and PGPB consortia with different ecological niches from hyperaccumulator Sedum alfredii Hance were used to compare their effects and mechanisms on plant growth condition, Cd phytoextraction efficiency, soil enzymatic activities, and rhizospheric bacterial community of Brassica juncea L. The results showed that both rhizospheric and endophytic PGPB consortia inoculants promoted plant growth (6.9%-22.1%), facilitated Cd uptake (230.0%-350.0%) of oilseed rape, increased Cd phytoextraction efficiency (343.0%-441.0%), and enhanced soil Cd removal rates (92.0%-144.0%). PGPB consortia inoculants also enhanced soil microbial carbon by 22.2%-50.5%, activated the activities of soil urease and sucrase by 74.7%-158.4% and 8.4%-61.3%, respectively. Simultaneously, PGPB consortia inoculants increased the relative abundance of Flavobacterium, Rhodanobacter, Kosakonia, Pseudomonas and Paraburkholderia at the genus level, which may be beneficial to plant growth promotion and bacterial phytopathogen biocontrol. Although the four PGPB consortia inoculants promoted oilseed growth, amplified Cd phytoextraction, and changed bacterial community structure in rhizosphere soil, their original ecological niches were not a decisive factor for the efficiency of PGPB consortia. therefore, the results enriched the present knowledge regarding the significant roles of PGPB consortia as bioaugmentation agents and preliminarily explored construction principles of effective bioaugmentation inoculants, which will provide insights into the microbial responses to combined inoculation in the Cd-contaminated soils.

Metagenomic insights into soil microbial communities involved in carbon cycling along an elevation climosequences.

Diversity and community composition of soil microorganisms along the elevation climosequences have been widely studied, while the microbial metabolic potential, particularly in regard to carbon (C) cycling, remains unclear. Here, a metagenomic analysis of C related genes along five elevations ranging from 767 to 4190 m at Mount Kilimanjaro was analysed to evaluate the microbial organic C transformation capacities in various ecosystems. The highest gene abundances for decomposition of moderate mineralizable compounds, i.e. carbohydrate esters, chitin and pectin were found at the mid-elevations with hump-shaped pattern, where the genes for decompositions of recalcitrant C (i.e. lignin) and easily mineralizable C (i.e. starch) showed the opposite trend (i.e. U-shaped pattern), due to high soil pH and seasonality in both low and high elevations. Notably, the gene abundances for the decompositions of starch, carbohydrate esters, chitin and lignin had positive relationships with corresponding C compounds, indicating the consistent responses of microbial functional profiles and metabolites to elevation climosequences. Understanding of adaptation of microbial communities, potential function and metabolites to elevation climosequences and their influencing factors provided a new insight for the regulation of terrestrial C storage.

Distinct rhizobacterial functional assemblies assist two Sedum alfredii ecotypes to adopt different survival strategies under lead stress.

Lead (Pb) contamination presents a widespread environmental plague. Sedum alfredii is widely used for soil phytoremediation owing to its capacity to extract heavy metals, such as Pb. Although efficient Pb extraction is mediated by complex interactions between the roots and rhizospheric bacteria, the mechanism by which S. alfredii recruits microorganisms under Pb stress remains unclear. The Pb-accumulating ecotype (AE) and non-accumulating ecotype (NAE) of S. alfredii recruited different rhizobacterial communities. Under Pb stress, AE rhizosphere-enriched bacteria assembled into stable-connected clusters with higher phylogenetic and functional diversity. These microbes, e.g., Flavobacterium, could release indoleacetic acid to promote plant growth and siderophores, thereby increasing Pb availability. The NAE rhizosphere-enriched functional bacteria "desperately" assembled into highly specialized functional clusters with extremely low phylogenetic diversity. These bacteria, e.g., Pseudomonas, could enhance phosphorus solubilization and Pb precipitation, thereby reducing Pb stress and plant Pb accumulation. High niche overlap level of the rhizo-enriched species raised challenges in soil resource utilization, whereas the NAE community assembly was markedly constrained by environmental "selection effect" than that of AE rhizobacterial community. These results indicate that different ecotypes of S. alfredii recruit distinct bacterial functional assemblies to drive specific plant-soil feedbacks for different survival in Pb-contaminated soils. To cope with heavy metal stress, NAE formed a highly functional and specialized but vulnerable community and efficiently blocked heavy metal absorption by plants. However, the AE community adopted a more stable and elegant strategy to promote plant growth and the accumulation of dry matter via multiple evolutionary strategies that ensured a high yield of heavy metal phytoextraction. This for the first time provides new insights into the roles of rhizosphere microbes in plant adaptations to abiotic stresses.

The Effects of Exposed Specific Facets and Sulfation on the Surface Acidity of Cu2 O Solids.

Cuprous oxide microcrystals with {111}, {111}/{100}, and {100} exposed facets were synthesized. 31 P MAS NMR using trimethylphosphine as the probe molecule was employed to study the acidic properties of samples. It was found that the total acidic density of samples increases evidently after sulfation compared with the pristine cuprous oxide microcrystals. During sulfation, new {100} facets are formed at the expense of {111} facets and lead to the generation of two Lewis acid sites due to the different binding states of SO4 2- on {111} and {100} facets. Moreover, DFT calculation was used to illustrate the binding models of SO4 2- on {111} and {100} facets. Also, a Pechmann condensation reaction was applied to study the acidic catalytic activity of these samples. It was found that the sulfated {111} facet has better activity due to its higher Lewis acid density compared with the sulfated {100} facet.

Morphology-Dependent Catalytic Activity of Ru/CeO2 in Dry Reforming of Methane.

Three morphology-controlled CeO2, namely nanorods (NRs), nanocubes (NCs), and nanopolyhedra (NPs), with different mainly exposed crystal facets of (110), (100), and (111), respectively, have been used as supports to prepare Ru (3 wt.%) nanoparticle-loaded catalysts. The catalysts were characterized by H2-temperature programmed reduction (H2-TPR), CO⁻ temperature programmed desorption (CO-TPD), N2 adsorption⁻desorption, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectroscopy (XDS). The characterization results showed that CeO2-NRs, CeO2-NCs, and CeO2-NPs mainly expose (110), (100) and (111) facets, respectively. Moreover, CeO2-NRs and CeO2-NCs present higher oxygen vacancy concentration than CeO2-NPs. In the CO2 reforming of methane reaction, Ru/CeO2-NR and Ru/CeO2-NC catalysts showed better catalytic performance than Ru/CeO2-NPs, indicating that the catalysts with high oxygen vacancy concentration are beneficial for promoting catalytic activity.

Mapping surface-modified titania nanoparticles with implications for activity and facet control.

The use of surface-directing species and surface additives to alter nanoparticle morphology and physicochemical properties of particular exposed facets has recently been attracting significant attention. However, challenges in their chemical analysis, sometimes at trace levels, and understanding their roles to elucidate surface structure-activity relationships in optical (solar cells) or (photo)catalytic performance and their removal are significant issues that remain to be solved. Here, we show a detailed analysis of TiO2 facets promoted with surface species (OH, O, SO4, F) with and without post-treatments by 31P adsorbate nuclear magnetic resonance, supported by a range of other characterization tools. We demonstrate that quantitative evaluations of the electronic and structural effects imposed by these surface additives and their removal mechanisms can be obtained, which may lead to the rational control of active TiO2 (001) and (101) facets for a range of applications.Metal oxide nanocrystals can be grown with different facets exposed to give variations in reactivity, but the chemical state of these surfaces is not clear. Here, the authors make use of a phosphine probe molecule allowing the differences in surface chemistry to be mapped by NMR spectroscopy.

Trimethylphosphine-Assisted Surface Fingerprinting of Metal Oxide Nanoparticle by (31)P Solid-State NMR: A Zinc Oxide Case Study.

Nano metal oxides are becoming widely used in industrial, commercial and personal products (semiconductors, optics, solar cells, catalysts, paints, cosmetics, sun-cream lotions, etc.). However, the relationship of surface features (exposed planes, defects and chemical functionalities) with physiochemical properties is not well studied primarily due to lack of a simple technique for their characterization. In this study, solid state (31)P MAS NMR is used to map surfaces on various ZnO samples with the assistance of trimethylphosphine (TMP) as a chemical probe. As similar to XRD giving structural information on a crystal, it is demonstrated that this new surface-fingerprint technique not only provides qualitative (chemical shift) but also quantitative (peak intensity) information on the concentration and distribution of cations and anions, oxygen vacancies and hydroxyl groups on various facets from a single deconvoluted (31)P NMR spectrum. On the basis of this technique, a new mechanism for photocatalytic •OH radical generation from direct surface-OH oxidation is revealed, which has important implications regarding the safety of using nano oxides in personal care products.

Facet-dependent acidic and catalytic properties of sulfated titania solid superacids.

Sulfated titania solid superacids with dominant {001}, {001}/{101}, and {101} facets were prepared by the hydrothermal method and subsequent sulfation. Their facet-dependent acidic properties were investigated by the solid-state (31)P NMR technique and Pechmann condensation of 5,7-dihydroxy-4-methyl coumarin.

Calorimetric and theoretical study of the interaction between some saccharides and sodium halide in water.

Dilution enthalpies and mixing enthalpies of sodium halide and some saccharides (glucose, galactose, xylose, arabinose, fructose, and sucrose) in aqueous solution were determined by calorimetric measurements at 298.15 K. The values were used to determine enthalpic pair interaction parameters. Combined with Gibbs energy pair parameters, entropic pair interaction parameters were also obtained. Theoretical calculations at the B3LYP/6-311++G(d,p) level were carried out to provide the information of structures and thermodynamic functions. The information reveals the thermodynamic essence of the interactions between sodium halide and saccharides in aqueous solutions. The experimental results and theoretical calculations show that the sign of enthalpic pair interaction parameter 2υh(ES) is determined by the direct interaction between saccharides and ions, whereas the difference in value of 2υh(ES) for different saccharides or electrolytes depends on the partial dehydration of saccharides or anions in aqueous solution. The difference in value of entropic pair interaction parameters depends partly on the different dominant interactions in the process of partial dehydration of saccharides or ions. An enthalpy-entropy compensation relationship was observed for the sodium bromide-aldopyranose-water systems. Remarkably, it can be conjectured that the hydration entropy of glucose is lower than for other monosaccharides. Perhaps it is one of the reasons why glucose plays an important role in living organisms rather than other monosaccharides.