Search Results (1,207)

Cyanobacteria are increasingly recognised as photosynthetic chassis for sustainable metabolic engineering because oxygenic photosynthesis generates ATP and NADPH via the photosynthetic electron transport chain, which drive CO₂ fixation through the Calvin–Benson–Bassham cycle into carbon intermediates that can be redirected toward engineered heterologous pathways. Their genetic tractability, CO₂-fixing capacity, ecological adaptability, and relatively simple cellular organisation make them attractive platforms for developing low-carbon biotechnological processes. This review explores recent progress in engineering cyanobacteria for heterologous pathway construction, critically evaluating genetic tools including transformation methods, genome integration strategies, promoter systems, and CRISPR-based editing, with specific emphasis on challenges of direct relevance to phototrophic chassis: host–pathway metabolic compatibility, precursor supply, cofactor balancing between photosynthetic output and heterologous pathway demand, and achieving genetic stability in polyploid cyanobacterial genomes. The review also addresses key limitations with mechanistic context: metabolic burden from multi-gene pathway expression reduces growth rate and selects against producing cells; polyploidy delays complete chromosomal segregation of engineered constructs; slow photoautotrophic growth constrains volumetric productivity; native regulatory networks resist carbon flux redirection; and cultivation constraints—including light attenuation in dense cultures and mismatches between photosynthetic ATP/NADPH supply and heterologous pathway demand—further limit achievable yields. Full article

Common bean (Phaseolus vulgaris L.) is a strategic crop whose sustainable production depends on symbiosis with nitrogen-fixing bacteria. However, the composition and functional potential of the nodule microbiome in varieties adapted to semi-arid regions, such as northern Mexico, remain poorly documented. Therefore, this study evaluated the influence of host genotype on nodule-associated bacterial communities in three improved varieties (Pinto Bravo, NOD1, and Jamapa) under conventional management, using high-throughput sequencing of the V3–V4 regions of the 16S rRNA gene. Alpha and beta diversity analyses showed no significant differences among varieties, indicating a similar nodular microbiome regardless of genotype. At the phylum level, Proteobacteria and Bacteroidota predominated, suggesting a conserved microbial core. At the genus level, Rhizobium was the most abundant taxon, while non-rhizobial genera such as Acinetobacter and the JC017 lineage were also detected. Functional prediction using PICRUSt2 revealed conserved metabolic profiles, with dominant pathways associated with amino acid biosynthesis, carbon metabolism, aerobic respiration, and fatty acid biosynthesis, indicating metabolic redundancy linked to tolerance to osmotic, thermal, and oxidative stress. The results suggest that under semi-arid conditions, the symbiotic interaction is governed by mechanisms at the host species level (P. vulgaris), which ensure the recruitment of a functional core microbiome, whereas intraspecific variation among improved varieties may influence the recruitment of specific accessory taxa. Full article

Against the backdrop of global decarbonization in energy-intensive industries, the primary aluminum sector has become a critical field for deep industrial decarbonization due to its high electricity consumption, large share of indirect carbon emissions, and complex mitigation pathways. This challenge is particularly salient in regions endowed with abundant renewable resources while hosting concentrated industrial electricity demand, where coordinated mitigation across technological upgrading and energy system transformation has broad practical relevance. Using Xining in Qinghai Province, China, a renewable-rich region, as an illustrative case, this study systematically examines the major carbon mitigation pathways in the primary aluminum industry, including mining, alumina production, electrolytic cell retrofitting, power system coordination, and carbon capture, utilization, and storage (CCUS). A multi-objective optimization model is developed to minimize marginal abatement costs (MAC) while maximizing technological application performance, and the sequential unconstrained minimization technique (SUMT) is employed to optimize mitigation pathways under short-, medium-, and long-term scenarios. The results show that, in the short term (before 2030), emission reduction mainly relies on improvements in electrolysis efficiency, leading to a mitigation pattern dominated by reductions in electricity consumption per unit of output. In the medium term (before 2035), the pathway shifts from isolated process optimization to a coordinated strategy combining process upgrading with power decarbonization, exhibiting a structural mitigation pattern driven by synergy between the production side and the energy side. In the long term (before 2060), the pathway evolves toward a stage dominated by energy system reconfiguration and carbon utilization. With high shares of renewable electricity integration, DC power supply configurations, and energy storage support, primary aluminum production is expected to achieve deep decarbonization on the power side. This study provides a transferable analytical framework and policy-relevant insights for the low-carbon transition of energy-intensive industries in renewable-rich regions. Full article

The rapid proliferation of cloud data centers has intensified concerns over carbon emissions, energy efficiency, and sustainability. Virtual machine (VM) placement is a pivotal control lever, yet existing methods rarely couple carbon intensity signals with computationally tractable multi-objective optimization. In this paper, we propose CASO (Carbon-Aware Surrogate-Guided Optimization), a novel framework that integrates an online adaptive Radial Basis Function (RBF) surrogate model with a self-adaptive hybrid PSO-DE swarm optimizer for real-time VM placement in geo-distributed edge cloud environments. CASO simultaneously minimizes carbon emissions, energy consumption, SLA violation rate, and network latency under strict host capacity and Quality-of-Service (QoS) constraints. Three key innovations differentiate CASO: (i) an online surrogate update mechanism that refines fitness approximations incrementally as workload patterns evolve; (ii) a carbon intensity weighting scheme anchored to real-time Grid Emission Factor (GEF) signals; and (iii) an adaptive parameter controller that autonomously tunes swarm exploration–exploitation trade-offs without hand-crafting. Experiments on the publicly available Alibaba Cluster Trace (cluster-trace-v2026-GenAI) dataset within a CloudSim-Plus environment show that CASO reduces carbon emissions by up to 31.4%, energy consumption by 27.9%, and SLA violations by 18.8% compared to the strongest baseline while converging 3.8× faster than the strongest baseline (ADEDL). Full article

Current research suggests that the uranium enrichment in the Qianjiadian deposit, southwestern Songliao Basin (China), is closely related to hydrocarbon dissipation and deep thermal fluids. However, previous investigations have not carried out systematic in-depth research on the abundant calcite veins hosted in diabase within the ore district, especially regarding their types, genetic mechanisms, formation ages, and genetic links to uranium enrichment. In particular, whether their genesis is associated with the two critical ore-controlling factors (hydrocarbon dissipation and thermal fluid activities) remains poorly constrained and to be elucidated. Through analyses of major and trace element geochemistry, scanning electron microscopy, and fluid inclusion microthermometry on calcite veins within fractures of Lower Cretaceous diabase, this study confirms that the veins are products of epigenetic fluid infill with a medium-to-low temperature hydrothermal nature (115–215 °C). The direction of fluid migration was from north to south, consistent with the trend of hydrocarbon dissipation. In situ U-Pb dating yields Eocene (~42.9 Ma) and Pleistocene (1.57–2.82 Ma) ages for the calcite veins, which are highly consistent with the timing of diabase intrusion (early Eocene) and the main episodes of uranium mineralization (Eocene–Oligocene and Pleistocene). Carbon and oxygen isotope compositions and inclusion components indicate that the carbon source was mainly derived from dissipated hydrocarbons, rather than from sedimentary diagenesis or direct source rock generation. The C-O isotopic signatures reflect further carbon isotope fractionation following the interaction between dissipated hydrocarbons and groundwater, and the inclusion fluids, composed mainly of hydrocarbon gases and water, suggest that the carbon source for calcite vein formation was provided by dissipated hydrocarbons. The temporal coupling of hydrocarbon dissipation, calcite vein formation, uranium mineralization, and thermal input from diabase intrusion reflects the dynamic processes of basin evolution and tectonic reworking. The key dynamic backgrounds for this series of diagenetic and metallogenic events include Late Cretaceous tectonic inversion, Eocene–Oligocene tectonic uplift and erosion, and Pleistocene differential uplift and subsidence. The thermal effects from hydrocarbon dissipation and diabase intrusion were the primary factors driving the anomalous uranium enrichment that formed this super-large deposit. The formation of the calcite veins, along with their characteristics indicative of medium-to-low temperature hydrothermal activity and hydrocarbon dissipation, provides a critical window for understanding these processes and offers robust scientific evidence for this genetic model. This study, for the first time, systematically reveals that the calcite veins within the diabase of the Qianjiadian uranium mining area are of medium-to-low temperature hydrocarbon-bearing hydrothermal origin, and constrains their formation ages to the Eocene (~42.9 Ma) and Pleistocene (1.57–2.82 Ma), which are highly coupled with diabase intrusion and two episodes of uranium mineralization events. C-O isotopic and fluid inclusion evidence indicates that the formation of calcite veins directly records the process of hydrocarbon dissipation–groundwater mixing, providing a new mineralogical and geochronological evidence chain for thermal–hydrocarbon–uranium-coupled mineralization. Full article

Aliphatic diamines possess two amino functional groups and exhibit diverse chemical properties and tunable molecular structures. By selecting the guest [(C₂H_2n+4N₂), n = 2–6] and host 18-crown-6, and controlling the design and assembly processes via modulation by thiocyanate and a manganese salt, a series of dumbbell-shaped crown ether complexes, (C₂H_2n+6N₂)²⁺(18-crown-6)₂[Mn(NCS)₄]²⁻·(δ_n,₂C₂H₃N), n = 2–6, (1)–(5), was synthesized and analyzed by single-crystal X-ray diffraction (SCXRD) at 100 K and 293 K. Variable-temperature infrared and XRD analyses confirmed that compounds 3 and 5 underwent a phase transition. As the length of the carbon chain increases and alternates between odd and even, the interplanar dihedral angle of the crown ether exhibits a distinct pattern: Even-number chains arrange in parallel, whereas odd-number chains form a pronounced angle. This structural pattern influences macroscopic deformation of the crystal and induces corresponding periodic variations in the dielectric and electrochemical properties. The wide-bandgap insulators and magnetic properties are primarily governed by the inorganic components of the system and are less influenced by the organic portion. This study reveals principles for regulating supramolecular conformation and functional properties through the parity of the organic chain lengths, providing a strategy for the molecular-level design of supramolecular crystal materials with ordered structures and tunable properties. Full article

Folate is a central nutrient in one-carbon metabolism, contributing to nucleotide biosynthesis, methionine cycling, methyl-donor supply, and epigenetic regulation. In animals, the intestine is both a principal site of folate absorption and a key target organ for folate action. This narrative review focuses primarily on livestock, poultry, aquaculture species, ruminants, and animal-source food enrichment, while also using rodent, human, and in vitro studies as mechanistic or translational evidence. We synthesize evidence on folate absorption, transport, and metabolism and evaluate the mechanisms through which folate influences intestinal health. Available evidence suggests that adequate folate supply may support epithelial renewal, tight-junction integrity, mucosal immune balance, antioxidant capacity, gut microbiota stability, short-chain fatty acid production, and epigenetic regulation of intestinal development. These effects have been reported in poultry, pigs, fish, ruminants, rodents, and maternal–offspring models. However, the evidence is uneven across species, and dose–response relationships, folate forms, bioavailability, and species-specific requirements remain major limitations for translating current knowledge into animal production. Future studies should compare folic acid, 5-methyltetrahydrofolate, natural reduced folates, microbiota-derived folate, and folate-producing probiotics; quantify the contribution of microbiota-derived folate to host methyl-donor pools; and develop precision strategies that integrate folate with other one-carbon nutrients, probiotics, and product-enrichment technologies. Full article

Root rot is a major disease restricting the cultivation and production of Polygonatum kingianum Coll. et Hemsl. This study aimed to identify the causal agent and characterize its biological properties. Pathogens were isolated from diseased rhizomes showing typical symptoms, and their pathogenicity was confirmed through Koch’s postulates using both detached rhizome inoculation and field pot experiments with spore suspension irrigation, in which typical root rot symptoms were reproduced. Based on morphological characteristics and multi-locus phylogenetic analysis (ITS, CaM, RPB2, and TUB), the pathogen was identified as Penicillium crustosum. Biological characterization revealed that the optimal conditions for mycelial growth and sporulation were 25 °C and pH 8–9, with Czapek agar being the most suitable medium. Light conditions significantly influenced fungal development; continuous darkness (24 h) favored mycelial growth, while an alternating light/dark cycle (12 h/12 h) significantly enhanced sporulation. Furthermore, the pathogen exhibited the highest utilization efficiency for soluble starch as a carbon source and peptone or yeast extract as a nitrogen source. These physiological traits suggest a strong adaptive capacity of the pathogen to environmental conditions associated with host rhizomes, which may contribute to disease development under cultivation conditions. To our knowledge, this is the first report of P. crustosum causing root rot in P. kingianum. The findings provide a basis for accurate pathogen identification and improve current understanding of the biological characteristics of this pathogen, thereby supporting future studies on disease monitoring and management. Full article

The Nam Xan gold deposit is located in the central Truong Son Fold Belt of Laos. It is a newly identified distal intrusion-related gold system (IRGS) in a continental arc setting. This study uses whole-rock geochemistry, Pb and S isotope systematics, and mineral-scale analyses to trace magmatic evolution and ore-forming processes. Whole-rock data indicate that the associated intrusive suite is a calc-alkaline volcanic-arc granite (VAG) series, derived from a subduction-modified mantle source with notable crustal contributions. Pb isotopes reveal mixing arrays rather than true isochrons. Monte Carlo modeling shows binary mantle–crust mixing for igneous rocks and ternary mixing with an additional radiogenic component in ore samples, indicating enhanced fluid–rock interaction during mineralization. Sulfur isotope data show a shift from magmatic sulfur (δ³⁴S ≈ −5‰) in early skarn-stage pyrite to heavier values (δ³⁴S ≈ +6‰) in gold-bearing stages, reflecting fluid evolution driven by cooling and redox changes. Mineral chemistry data demonstrate that gold is present both as invisible gold within arsenian pyrite and as free gold in late-stage fractures. Strong correlations between Au and As, along with elevated Co/Ni ratios and enrichments in Bi, W, and F, collectively support a magmatic-hydrothermal origin. These findings define a three-stage mineralization process: an initial phase involving high-temperature magmatic fluids, a main stage characterized by sulfidation and gold deposition, and a final stage marked by polymetallic overprinting. The Nam Xan deposit is therefore interpreted as the distal manifestation of a Permian arc-related magmatic system in which magmatic fluids migrated along structural conduits and precipitated gold through interaction with carbonate host rocks. The identification of these intrusions in the distal IRGS at Nam Xan informs regional exploration models in the Truong Son Fold Belt, demonstrating the potential of carbonate platforms near Permian intrusions for future mineral exploration. Full article

Folate (vitamin B9) is central to one-carbon metabolism, supporting nucleotide biosynthesis, methylation homeostasis, and epigenetic regulation. The gut microbiome both produces and consumes folate, creating a bidirectional axis influencing host health and disease. We systematically reviewed 159 original studies from MEDLINE, Google Scholar, Embase, and Scopus (inception through January 2026) examining enteric microbiota–folate interactions, with intervention evidence graded using the Oxford Centre for Evidence-Based Medicine 2011 framework. Only a minority of gut bacteria possess complete folate biosynthetic pathways; most depend on cross-feeding from prototrophic taxa including Bifidobacterium, Lactobacillus, and Streptococcus. Altered microbial folate metabolism was associated with metabolic, gastrointestinal, oncologic, neuropsychiatric, cardiovascular, immunologic, and reproductive disorders through convergent mechanisms of disrupted methylation, genomic instability, and immune dysregulation. Probiotic interventions achieved the strongest evidence, supported by multiple human controlled and observational trials and animal models. The evidence for prebiotic, dietary, and folate supplementation interventions was moderate due to the predominant animal models and in vitro data. Overall, the predominant associational and observational evidence base is insufficient to establish causal relationships, underscoring the need for adequately powered human randomized controlled trials with folate-specific endpoints, multi-omics integration, and precision approaches matching folate form and dose to individual microbiome and host genetic profiles. Full article

The Mugan Syncline in northeastern Yunnan represents a significant relay area for shale gas exploration in China. However, due to the combined effects of tectonic superimposition and sedimentary heterogeneity, systematic investigations into the intervals hosting high-quality shales and the coupling relationships among microfacies, reservoir quality, and gas-bearing properties remain insufficient. The core objective of this study is to establish a high-resolution microfacies framework and to quantitatively elucidate the multi-parameter coupling mechanisms by which microfacies control organic matter enrichment, pore development, and gas storage capacity in this structurally complex, basin-margin setting. By integrating core observations, thin-section petrography, scanning electron microscopy (SEM), whole-rock X-ray diffraction (XRD), total organic carbon (TOC) analysis, trace-element geochemistry, and well-logging data, we establish a stratigraphic subdivision and cross-well correlation framework for the Wufeng (WF) Formation and the Long11 submember. Furthermore, a lithofacies (microfacies) identification scheme based on a “TOC + siliceous (quartz + feldspar)–carbonate–clay” ternary classification is applied. The results reveal the following: (1) Based on the locally developed erosional contact at the boundary between the Longmaxi (LMX) Formation and the underlying Guanyinqiao Formation, the WF Formation in the study area can be subdivided into two submembers, whereas the Long11 submember comprises four sublayers. The thicknesses of the Long11-1 through Long11-3 sublayers range from 21.42 to 25.47 m, exhibiting a subtle northward-thickening trend. In contrast, the Long11-4 sublayer displays a relatively uniform thickness and high stratigraphic continuity of shale deposition. (2) Based on TOC content and ternary mineral composition, the shales are classified into four lithofacies associations and sixteen lithofacies subtypes. The main favorable microfacies assemblages are identified as high-carbon siliceous/calcareous shale (C-1), high-carbon calcareous/siliceous mixed shale (M-1), carbon-rich argillaceous siliceous shale (S-3), and high-carbon siliceous/argillaceous mixed shale (M-2). (3) High-quality shales (TOC > 2%) are predominantly developed in the upper member of the WF Formation and in the Long11-1 through Long11-4 sublayers. Their lateral distribution is markedly controlled by variations in paleotopography and terrigenous sediment supply. (4) The microfacies exert a synergistic control on shale gas enrichment. Carbon-rich argillaceous siliceous and siliceous-rich microfacies generally correspond to higher TOC contents and better-developed organic-matter pores. Siliceous-rich and mixed microfacies exert a positive influence on pore preservation and rock brittleness. The gas-bearing properties are influenced not only by TOC content but also by pore structure, mineral composition, and tectonic preservation conditions. The findings of this study provide a scientific basis for the prediction of shale gas sweet spots and the optimization of target intervals in the Mugan Syncline and other structurally and sedimentologically complex regions of northeastern Yunnan. Full article

Coal rank exerts a fundamental control on the distribution of elements during density-based separation, yet this influence remains poorly understood. The primary objective of this study is to elucidate how coal rank governs the enrichment and partitioning of major, trace, and rare earth elements (REY) in float–sink products, and to assess the implications for clean coal utilization and critical metal recovery. To achieve this, three Late Paleozoic bituminous coals of different ranks from Shanxi Province, China, were subjected to density fractionation (1.3–1.8 g/cm³) combined with proximate and ultimate analyses, X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS), X-ray diffraction (XRD), and coal petrography. The results show that coal rank fundamentally governs element distribution and enrichment patterns. With increasing rank, the dominant inorganic minerals shift from clay minerals to carbonates, leading to pronounced differentiation in elemental affinities. In medium- to high-rank bituminous coals, chalcophile elements (e.g., As, Mo, Tl) associated with sulfides are significantly enriched in high-density fractions, whereas in high-rank bituminous coals, carbonate-related elements (e.g., Sr, Ca, Mg) show marked enrichment. Rare earth elements are primarily hosted in clay and phosphate minerals. Light rare earth elements dominate in medium- to high-rank coals, while middle rare earth elements increase in high-rank coals due to carbonate influence. Density-based separation effectively concentrates hazardous elements (e.g., As, Pb, Cd) in high-density tailings, demonstrating substantial potential for mitigating environmental risks. Meanwhile, critical metals such as lithium (Li), strontium (Sr), and REY are enriched in medium- to high-density products, with Li hosted in clay minerals and Sr strongly enriched in carbonate-rich high-rank coal (up to 1525 μg/g), indicating recoverable resources from coal processing wastes. Full article

Studying carbonate breccias enhances our understanding of various geological processes. Fieldwork in the vicinity of the Sakhray Massif in the Western Caucasus (western edge of the Caucasus Mountains) allowed us to discover a peculiar layer of carbonate breccia in the monotonous succession of Lower Triassic platy limestones. The lithological peculiarities of this breccia and the hosting rocks were examined in the field, as well as in polished slabs and thin sections. The results show that the breccia consists of a chaotic mass of chiefly angular clasts of entirely different limestones with abundant fossil debris and a micritic matrix similar to the hosting rocks but bearing siliciclastic debris. The age of the carbonate breccia is the same as that of the hosting rocks, i.e., it is late Induan–early Olenekian (Early Triassic), but the clasts are attributed to upper Changhsingian (Upper Permian) limestones (also reefal). It is proposed that these clasts were created by erosion in a subaerial environment, after which they were transported from a land mass to a deep sea. Apparently, extraordinary geological events (e.g., severe storms, earthquakes, or tsunamis) triggered submarine debris flows on a steep slope. From a practical point of view, the reported discovery extends the vision of the geological heritage of this part of the Western Caucasus. Full article

Igneous intrusions significantly modify the distribution and mobility of elements in coal. In order to explore the influence of igneous intrusions on the elements in coals, the No. 2-2 coal seam of the Shanxi Formation of Juji Coal Mine was selected as the research focus. The No. 2-2 coal was investigated using X-ray fluorescence spectrometry and a high-resolution inductively coupled plasma mass spectrometer. The results show that the volatile gases accompanying the igneous intrusion, together with CO₂ generated by reaction between the intrusion and the coal seam, led to marginally higher MnO and MgO in the thermally altered coals compared to unaltered coal, and also promoted reprecipitation of carbonate and silicate minerals, which increased loss on ignition. The content of P₂O₅ initially rises with increasing distance from the intrusion, indicating that contact metamorphism can lead to a depletion of major elements in thermally altered coals. Meanwhile, the igneous intrusion caused reprecipitation of silicate minerals, but the high temperatures from the intrusion pyrolyzed some of these minerals, resulting in Li, Sb, and U contents that increase with distance from the intrusion. In contrast, Ge, Mo, Ba, Eu, and Pb, together with hydrothermal fluids, entered the thermally metamorphosed coal via fractures and migrated downward, gradually accumulating within it; their contents therefore decrease with increasing distance. Additionally, the intrusion and associated hydrothermal fluids also induced positive Eu, Gd, and Y anomalies and negative Ce anomalies in the thermally altered coals, whereas intermediate-felsic source rocks and oxidizing conditions produced negative Eu, positive Ce, and weakly negative Y anomalies in coals farther from the intrusion. Contact metamorphism results in a significant element depletion, exerting negative effects. Conversely, hydrothermal fluids and fluids from the host rocks promote the redistribution and enrichment of elements in coal, producing positive effects. Overall, the negative effects outweigh the positive ones. Full article

Celestine (SrSO₄) is the principal ore of Sr and a sensitive tracer of diagenetic fluid–rock interaction in carbonate–evaporite successions. This study presents integrated petrographic mineral chemistry and Sr–S isotopic data for epigenetic celestine hosted by Asmari carbonates at Jabal Hafit, Al Ain (UAE), to constrain fluid source, and mechanisms of SrSO₄ precipitation during basin diagenesis. Field and SEM observations show celestine as stratabound, vug- and fracture-filling euhedral to subhedral crystals within dolomitised limestone, suggesting precipitation after initial lithification during early-to-mid burial diagenesis. Electron microprobe analyses show nearly stoichiometric SrSO₄ (55.15–57.30 wt.% SrO; 42.43–44.35 wt.% SO₃) with very low Ba and Ca. The characteristically high Sr/Ba signature of the celestine reflects a complex diagenetic history driven by efficient Sr remobilisation during carbonate recrystallisation within an inherently Ba-poor marine sequence. Measured ⁸⁷Sr/⁸⁶Sr ratios are tightly clustered (0.707841–0.707854) with a high degree of isotopic homogeneity, which indicates a stable, well-buffered fluid reservoir, while the absolute values align with an Oligocene marine signature. Sulphur isotope values (δ³⁴S = +27.3 to +29.1‰) are enriched relative to coeval marine sulphate, which could be attributed to closed-system Rayleigh fractionation driven by bacterial sulphate reduction. We propose that celestine precipitated from stable, marine-buffered burial brines, where supersaturation was achieved through coupled Sr enrichment from carbonate diagenesis and microbial modification of the sulphate reservoir. Full article