Search Results (2,713)

This study investigated the effects of bio-organic fertilizer (BF) containing plant growth-promoting bacterium Bacillus velezensis SS-20 on soil properties, microbial community structure, and C/N cycle functional genes. The results showed that compared with chemical fertilizer (CF) and deactivated bio-organic fertilizer (BFD) treatments, BF significantly improved soil physicochemical properties. Soil pH, organic matter, total nitrogen, total potassium, and total phosphorus content under BF treatment were increased by 14.8%, 56.5%, 48.2%, 38.8%, and 58.4%, respectively, compared to the control; soil urease and sucrase activities increased by 3.5 and 2.4 times those of CF treatment, respectively. Meanwhile, BF increased pakchoi yield by 11.2% (vs. CF). BF treatment enhanced the relative abundance of beneficial bacteria Actinomycetota by 28.4% compared with the BFD treatment and raised that of fungi Ascomycota to 1.9 times that of the control. At the genus level, BF significantly enriched biocontrol-relevant genus Pseudogymnoascus, whose abundance reached three times that of CF treatment, while the abundance of potentially harmful genus Penicillium decreased by 82%. BF also led to a high degree of synergy in carbon and nitrogen cycles. Functional gene analysis indicated that BF down-regulated multiple carbon-degrading genes, increased organic nitrogen metabolism genes by 5.3%, and reduced denitrification genes by 13.3%. Overall, bio-organic fertilizer optimized the soil microenvironment, regulated the microbial community structure, and improved C/N use efficiency and plant growth by introducing functional microorganisms and organic matter. Full article

Antimicrobial resistance is a growing global health threat, necessitating alternatives to conventional antibiotics. Bacteriophages, viruses that specifically target bacteria, represent a promising option, and phage-loaded electrospun fibers have recently gained attention as wound dressings for localized phage therapy. However, the influence of phage morphology and scaffold design has been largely overlooked. This study investigates how phage morphology and structure, in conjunction with scaffold design and processing conditions, may influence the biological performance of electrospun scaffolds. A bilayer scaffold was developed comprising a supportive polycaprolactone (PCL)/gelatin (70:30) layer and a polyvinyl alcohol (PVA) top layer loaded with bacteriophages. Two phage types, short-tailed podovirus APTC-SL.1 and long-tailed myovirus APTC-Efa.20, were incorporated into PVA fibers to evaluate their antibacterial activity against Staphylococcus lugdunensis and Enterococcus faecalis, respectively. The fibers were characterized using XRD, FTIR, TGA, optical microscopy, SEM, TEM, wettability analysis, and in vitro degradation tests. Biological assessments included antimicrobial testing, phage viability, and phage release. The bilayer scaffold containing short-tailed phages preserved phage viability and produced clear zones of lysis against S. lugdunensis, with ≈8.15% viability retained after electrospinning and relatively controlled release, whereas long-tailed phages showed no antibacterial activity. These results suggest that phage structure and morphology, together with electrospinning conditions and scaffold architecture, may play an important role in maintaining phage functionality in wound dressing applications, while acknowledging that host–phage interactions may also contribute to the observed differences. Full article

Polypropylene microplastics (PP-MPs) represent a persistent class of marine pollutants due to their hydrophobicity, high crystallinity, and resistance to environmental degradation. This review summarizes recent advances in understanding the environmental behavior, physicochemical aging, and ecotoxicological risks of PP-MPs, with emphasis on microbial degradation pathways involving bacteria, fungi, algae, and filter-feeding invertebrates. The biodegradation of PP-MPs is jointly regulated by environmental conditions, polymer properties, and the structure and function of plastisphere communities. Although photo-oxidation and mechanical abrasion enhance microbial colonization by increasing surface roughness and introducing oxygenated functional groups, overall degradation rates remain low in marine environments. Emerging mitigation strategies include biodegradable polymer alternatives, multifunctional catalytic and adsorptive materials, engineered microbial consortia, and integrated photo–biodegradation systems. Key research priorities include elucidating molecular degradation mechanisms, designing programmable degradable materials, and establishing AI-based monitoring frameworks. This review provides a concise foundation for developing ecologically safe and scalable approaches to PP-MP reduction and sustainable marine pollution management. Full article

Microorganisms live in a wide range of environments, performing diverse roles either independently or in association with other organisms forming consortia. This study is focused on those with the ability to bioremediate environments contaminated with petroleum hydrocarbons (PHCs), that is, the case of bacteria, fungi, algae, and consortia. PHC contamination constitutes a major global environmental issue, and presents a serious ecological risk. This research was conducted in the coastal waters of Haina Port (Dominican Republic) and the main objective was to characterise the bacterial communities with bioremediation capacity by sequencing the 16S rRNA. The samples were collected in sterile conditions, and physicochemical and molecular analyses were conducted. The results revealed the composition and distribution of bacterial communities in the area. At the phylum level, Proteobacteria is the dominant group, accounting for 70–90% of the community. At the class level, Gammaproteobacteria is the predominant group, followed by Alphaproteobacteria which ranks second in relative abundance. Bacillaceae appears as the most abundant family at most points. This 16S rRNA survey provides a taxonomic baseline of the microbial community, identifying taxa with documented degradative potential. Future functional analyses and culture studies are required to quantify and confirm the active metabolic pathways of the detected microorganisms. Full article

Background/Objectives: Water pollution caused by human activities disrupts ecosystems and promotes the spread of antimicrobial resistance genes (ARGs), posing a public health threat. This study investigated the presence of resistant Gram-negative bacteria and resistance genes in water from two sites occasionally exposed to domestic and hospital effluents, the Carioca River (CR) and Rodrigo de Freitas Lagoon (RFL), both used for recreation. Methods: Physicochemical parameters and coliform levels were measured. Bacterial isolates were identified by Matrix-Assisted Laser Desorption Ionization–Time-of-Flight Mass Spectrometry (MALDI-TOF MS) and tested for antimicrobial susceptibility using disk diffusion. The Minimum Inhibitory Concentration (MIC) was determined using the E-test^® and broth microdilution methods. PCR was used to detect carbapenem resistance and other ARGs from the DNA of bacterial isolates obtained from water samples. Results: CR presented signs of environmental degradation, with low dissolved oxygen and high coliform counts. One Citrobacter braakii isolate showed resistance to all tested antimicrobials, raising concern for untreatable infections. Carbapenem-resistant isolates accounted for 49.4% of the total, harboring bla_KPC (20%), bla_TEM (5%), bla_VIM (5%), and bla_SPM (5%). The intl1 gene was found in 10% of isolates, indicating potential horizontal gene transfer. Conclusions: The findings from a one-day sampling reveal the presence of multidrug-resistant bacteria that carry antimicrobial resistance genes in polluted aquatic systems. These highlight the connection between water contamination and antimicrobial resistance. The evidence underscores the urgent need for environmental monitoring and effective management strategies to reduce public health risks. Full article

The integration of oil-degrading microorganisms with phytoremediation has the potential to generate a synergistic effect in the removal of petroleum pollutants. This study analyzed the influence of two aquatic plant species (Eichhornia crassipes and Pistia stratiotes) and hydrocarbon-oxidizing bacterial strains (Rhodococcus erythropolis and Pseudomonas brenneri), as well as a microbial preparation, on the formation of bacterial consortia under oil-polluted conditions. The study assessed the losses of petroleum alkanes, the rheological properties of water, and the structure of emerging rhizospheric microbial communities by high-throughput sequencing. E. crassipes demonstrated a higher potential for stimulating the development of an oil-oxidizing microbial community. However, the introduced bacterial strains did not establish themselves within the formed microbial community, indicating the complexity of selecting compatible plant–microbe combinations for efficient bioremediation. Nevertheless, this approach remains a promising direction for enhancing the efficiency of hydrocarbon degradation in aquatic ecosystems. Full article

Hermetia illucens can digest toxic castor meal and tolerate ricinine stress. However, the underlying mechanisms of ricinine degradation and detoxification within the larval gut microbiome remain largely unknown. Here, the enhanced degradation kinetic process, and the roles of the gut bacterial community and metabolomics were investigated. When the ricinine content was 1000 mg kg⁻¹ in feeding substrate, larval development was not significantly affected. The ricinine degradation kinetics, facilitated by larval digestion, were significantly enhanced, reducing the degradation half-life to 5.13 days. The gut bacterial community structure adjusted in response to ricinine stress, suggesting that genera such as Dysgonomonas, Actinomyces, Phascolarctobacterium, Lachnoclostridium and Sedimentibacter might play key roles in ricinine resistance and degradation. Furthermore, the gut microbial metabolism responded to toxin stress, reflected by variations in metabolite expression and the enrichment of key metabolic pathways involved in amino acid and vitamin metabolism. This emphasizes the potential role of microbial metabolism in ricinine degradation and detoxification. The close association between gut bacteria and metabolites suggests a cooperative metabolic network within the gut microbiota, where bacteria may participate in ricinine degradation and detoxification either directly or through metabolic cooperation. These findings provide insights into host–microbe interactions and ricinine resistance, highlighting the need for further exploration into the microbiota’s role in host metabolism and the development of new therapeutic strategies. Full article

Lignin is a complex aromatic polymer that constitutes a major fraction of plant biomass and represents a valuable renewable carbon resource. Naturally decaying wood serves as an environmental reservoir of microorganisms capable of degrading lignin. In this study, we isolated and characterized sixteen bacterial strains from decaying Tilia cordata wood using an enrichment culture technique with lignin as the sole carbon source. Taxonomic identification via 16S rRNA gene sequencing revealed microbial diversity spanning the genera Bacillus, Pseudomonas, Stenotrophomonas, and several members of the Enterobacteriaceae family, including Raoultella terrigena isolates. Metagenomic sequencing of the wood substrate revealed an exceptionally rich and balanced bacterial community (Shannon index H′ = 5.07), dominated by Streptomyces, Bradyrhizobium, Bacillus, and Pseudomonas, likely reflecting a specialized consortium adapted to lignin rich late-stage decay. Functional phenotyping demonstrated that all isolates possess ligninolytic potential, evidenced by peroxidase/laccase-type activity through methylene blue decolorization. Dynamic Light Scattering (DLS) and HPLC analyses showed that some isolates, such as Raoultella terrigena MGMM806, effectively depolymerized lignosulfonate into low molecular weight fragments (1.23 nm), while others accumulated intermediate metabolites or completely mineralized the substrate. Growth profiling on monolignol substrates revealed a broad spectrum of catabolic specialization in lignin monomer degradation. The results demonstrate a complex system of metabolic partitioning within a natural bacterial consortium. This collection represents a foundational genetic resource for developing engineered biocatalysts and synthetic microbial communities aimed at the efficient conversion of lignin into valuable aromatic compounds. Full article

Biosurfactants produced by halophilic bacteria are gaining attention as eco-friendly and biocompatible alternatives to synthetic surfactants due to their high surface activity, stability under extreme conditions, and intrinsic antimicrobial properties. These amphiphilic biomolecules hold great promise for bioremediation, biomedical, and pharmaceutical applications. In this study, moderately halophilic bacteria capable of biosurfactant production were isolated from saline mud collected at the Burgas solar salterns (Bulgaria). The halophilic microbiota was enriched in Bushnell–Haas (BH) medium containing 10% NaCl amended with different carbon sources. Primary screening in BH liquid medium evaluated the isolates’ ability to degrade n-hexadecane while at the same time producing biosurfactants. Thirty halophilic bacterial strains were isolated on BH agar plates supplemented with 2% n-hexadecane, 2% olive oil, or 2% glycerol. Four isolates—BS7OL, BS8OL, BS9GL, and BS10HD—with strong emulsifying activity (E₂₄ = 56%) and reduced surface tension in the range of 27.3–45 mN/m were derived after 7 days of batch fermentation. Strain BS10HD was chosen as the most potent biosurfactant producer. Its phylogenetic affiliation was determined by 16S rRNA gene sequence analysis; according to the nucleotide sequence, it was assigned to Halomonas ventosae. The extract material was analysed by thin-layer chromatography (TLC) and Fourier transform infrared spectroscopy (FTIR). Upon spraying the TLC plate with ninhydrin reagent, the appearance of a pink spot indicated the presence of amine functional groups. FTIR analysis showed characteristic peaks for both lipid and peptide functional groups. Based on the observed physicochemical properties and analytical data, it can be suggested that the biosurfactant produced by Halomonas ventosae BS10HD is a lipopeptide compound. Full article

C-reactive protein (CRP) and serum amyloid A (SAA) are classical acute-phase proteins that exemplify humoral innate immunity, the soluble arm of the host’s first-line defense. Beyond their traditional use as biomarkers of inflammation, both proteins function as active effectors against pathogens by binding microbial components, activating complements, and modulating inflammation. However, bacteria, viruses, and fungi have co-evolved diverse mechanisms to cope with or evade these host defenses. This review aims to summarize the current understanding of CRP and SAA as soluble innate immune effectors and to highlight pathogen strategies to counteract their antimicrobial pressure. We systematically surveyed and summarized evidence from experimental and clinical studies describing “function of CRP and SAA during infection”, “CRP and SAA in innate immune defense”, and “evasion mechanisms across bacterial, viral, and fungal pathogens”. CRP and SAA are rapidly upregulated in response to infection and contribute to pathogen recognition, opsonization, and inflammation. Pathogens, however, employ multiple coping strategies, including surface modification to block CRP binding, proteolytic degradation of acute-phase proteins, shielding within biofilms, and subversion of host signaling. These countermeasures enable microbes to reduce immune clearance and promote persistence. CRP and SAA represent central elements of humoral innate immunity, shaping the outcome of host–pathogen interactions. Pathogen adaptations to these proteins illustrate an ongoing evolutionary arms race between host defense and microbial survival. A deeper understanding of these processes may open avenues for novel therapeutic approaches, such as targeting microbial evasion factors or enhancing host acute-phase responses. Full article

Diet plays a pivotal role in shaping the gut microbiota, influencing host physiology, immune function, and nutrient metabolism. In this study, we evaluated the impact of three distinct feeding systems—Forage only, Balanced feed only, and Mixed system—on the cecal microbiota of guinea pigs (Cavia porcellus) using 16S rRNA gene amplicon sequencing in a randomized allocation of 18 males across the three diets (n = 6 per group) over 7 weeks. A total of 2,135,852 high-quality reads were obtained, with rarefaction curves and Good’s coverage confirming sufficient sequencing depth. Alpha diversity indices revealed significantly higher microbial richness and evenness in the mixed group, while beta diversity analyses demonstrated distinct microbial community structures across diets. Taxonomic profiling showed that forage-based diets enriched fiber-degrading genera such as Fibrobacter and Treponema, whereas the Balanced feed group favored mucin- and protein-degrading bacteria like Akkermansia and Bacteroides. LEfSe and t-test analyses identified several biomarkers and diet-specific genera, suggesting functional divergence in microbial metabolism. Forage-fed animals showed microbiota associated with short-chain fatty acid production and enhanced fiber utilization, while the Balanced feed group showed microbial traits linked to mucin degradation and potential gut barrier disruption. These findings highlight the strong influence of dietary composition on gut microbial ecology and suggest that fiber-rich diets promote a more diverse and functionally beneficial cecal microbiome in guinea pigs. Full article

Infectious pathogens pose serious threats to public health, necessitating the development of more antimicrobials. In this study, oligohydroxybutyrates were obtained through the catalyzed polymerization of β-butyrolactone using N, N-dimethyl-4-aminopyridine (DMAP) and aluminum isopropoxide [Al(OiPr)₃] and applied as sustainable antimicrobial agents. The poly3-hydroxybutyrate (PHB) oligomers exhibited broad-spectrum antibacterial activities against both Gram-negative (E. coli) and Gram-positive (S. aureus) model bacteria. Additionally, PHB oligomers displayed robust (inhibiting rate: >95%) and rapid (action time: <20 min) antiviral activity against three notorious single-stranded RNA viruses, that is, influenza A virus (H1N1 and H3N2) and coronavirus (SARS-CoV-2). In particular, a comprehensive set of advanced experimental characterizations, including FT-IR, ¹H- and ¹³C-NMR, and H-ESI-MS/MS, was applied to analyze their chemical structures. The results confirmed the loss of terminal hydroxyl groups in the PHB intermediate and end products associated with theoretical calculations. These findings will also help provide deep insight into the major chain growth mechanism during the synthesis of PHB. The structural variations, which were treated as unwanted side reactions, were identified as a pivotal factor by deactivating the terminal hydroxy during chain growth. Their effective sterilization properties and degradability endowed the as-prepared PHB oligomers with a promising biomedical potential, including for use as disinfectants, sanitizers, and antiseptics. Full article

To address the challenges of low land use efficiency, soil degradation, and high management costs in Ilex asprella cultivation, this study established an I. asprella–Grona styracifolia intercropping system and systematically evaluated its effects on soil nutrient cycling, microbial communities, and crop growth. Field experiments were conducted in Yunfu City, Guangdong Province, with monoculture (LCK for I. asprella, DCK for G. styracifolia) and three intercropping densities (HDT, LDT, MDT). Combining 16S rRNA sequencing and metagenomics, we analyzed the functional profile of the rhizosphere microbiome. The results showed that intercropping significantly increased the biomass of G. styracifolia, with the medium-density (MDT) treatment increasing plant length and fresh weight by 41.2% and 2.4 times, respectively, compared to monoculture. However, high-density intercropping suppressed the accumulation of medicinal compounds. In terms of soil properties, intercropping significantly enhanced soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and available nitrogen (AN) in the rhizosphere of both plants. Specifically, AN in the I. asprella rhizosphere increased by 18.9%. Soil urease and acid phosphatase activities were also elevated, while pH decreased. Microbial analysis revealed that intercropping reshaped the rhizosphere microbial community structure, significantly increased the Shannon diversity index of bacteria in the G. styracifolia rhizosphere, and enhanced the complexity of the microbial co-occurrence network. Metagenomic analysis further confirmed that intercropping enriched functional genes related to carbon fixation, nitrogen cycling (nitrogen fixation, assimilatory nitrate reduction), and organic phosphorus mineralization (the phoD gene), thereby driving the transformation and availability of soil nutrients. These findings demonstrate that the I. asprella–G. styracifolia intercropping system, particularly at medium density, effectively improves soil fertility and land use efficiency by regulating rhizosphere microbial functions, providing a theoretical basis for the sustainable ecological cultivation of I. asprella. Full article

Both organic matter and iron oxide (FeO) dynamics pose key roles in soil cadmium (Cd) bioavailability. However, the microbially driven transformation of soil organic matter and FeO and their linkages to Cd fractions remain unclear under reductive soil disinfestation (RSD) with different organic sources, which limits our mechanistic understanding of Cd immobilization by RSD. To address this gap, we conducted a 45 day microcosm experiment using a paddy soil contaminated with 22.8 mg/kg Cd. Six treatments were established: untreated control (CK), waterlogged (WF), and RSD-amended soils with 0.7% or 2.1% wheat straw (LWD, HWD) or soybean meal (LSD, HSD). We systematically assessed soil Cd fractionation, organic carbon and FeO concentrations, and bacterial community structure, aiming to clarify differences in Cd immobilization efficiency and the underlying mechanisms between wheat straw and soybean meal. For strongly extractable Cd, wheat straw RSD reduced the soil Cd concentrations from 6.02 mg/kg to 4.32 mg/kg (28.2%), whereas soybean meal RSD achieved a maximum reduction to 2.26 mg/kg (62.5%). Additionally, the soil mobility factor of Cd decreased from 44.6% (CK) to 39.2% (HWD) and 32.5% (HSD), while the distribution index increased from 58.5% (CK) to 62.2% (HWD) and 66.8% (HSD). Notably, the HWD treatment increased soil total organic carbon, humus, and humic acid concentrations by 34.8%, 24.6%, and 28.3%, respectively. Regarding amorphous FeO, their concentrations increased by 19.1% and 33.3% relative to CK. RSD treatments significantly altered soil C/N ratios (5.91–12.5). The higher C/N ratios associated with wheat straw stimulated r-strategist bacteria (e.g., Firmicutes, Bacteroidetes), which promoted carbohydrate degradation and fermentation, thereby enhancing the accumulation of humic substances. In contrast, the lower C/N ratios of soybean meal increased dissolved organic carbon and activated iron-reducing bacteria (FeRB; e.g., Anaeromyxobacter, Clostridium), driving iron reduction and amorphous iron oxide formation. PLS-PM analysis confirmed that wheat straw RSD immobilized Cd primarily through humification, whereas soybean meal RSD relied on FeRB-mediated FeO amorphization. These findings suggest that Cd immobilization in soil under RSD may be regulated by microbially mediated organic matter transformation and iron oxide dynamics, which was affected by organic materials of different C/N ratios. Full article

Patulin (PAT) is a fatal mycotoxin that exerts serious threats to human and animal health. Biodegradation of PAT is considered to be one of the promising ways for controlling its contamination. In this study, Lactiplantibacillus plantarum 6076 (LP 6076) with reliable removal efficiency on PAT was screened out from three lactic acid bacteria (LAB) strains. It was found that the PAT was eliminated through degradation by LP 6076, and the intracellular proteins played a crucial role in PAT degradation with the induction of PAT. The proteomic analysis showed that the response of LP 6076 to PAT was by a concerted effort to repair DNA damage, in parallel to adaptive changes in cell wall biosynthesis and central metabolism. Eleven differentially expressed proteins with high fold changes were picked out and identified as PAT degradation candidate enzymes. The 3D structures of the candidate enzymes were predicted, and molecular docking between the enzymes and PAT was performed. Five enzymes, including Acetoin utilization AcuB protein (AU), GHKL domain-containing protein (GHLK), Dihydroneopterin aldolase (DA), YdeI/OmpD-associated family protein (YDEL), and Transcription regulator protein (TR), could dock with PAT with lower affinity and shorter distance. Through molecular docking analysis, DA was ultimately identified as a potential key degrading enzyme. The choice of DA was substantiated by its superior combination of strong binding affinity and a productive binding pose with PAT. VAL84 and GLN51 residues of DA were likely the active sites, forming four hydrogen bonds with PAT. Our study could accelerate the commercial application of biodegradation toward PAT decontamination. Full article