Search Results (163)

Water systems serve as multifaceted environmental pools for antibiotic-resistant bacteria (ARB) and resistance genes (ARGs), influencing human, animal, and ecosystem health. This review synthesizes current understanding of how antibiotics, ARB, and ARGs enter surface, ground, and drinking waters via wastewater discharge, agricultural runoff, hospital effluents, and urban stormwater. We highlight key mechanisms of biofilm formation, horizontal gene transfer, and co-selection by chemical stressors that facilitate persistence and spread. Case studies illustrate widespread detection of clinically meaningful ARB (e.g., Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) and mobile ARGs (e.g., sul1/2, tet, bla variants) in treated effluents, recycled water, and irrigation return flows. The interplay between treatment inefficiencies and environmental processes underscores the need for advanced treatment technologies, integrated monitoring, and policy interventions. Addressing these challenges is critical to curbing the environmental dissemination of resistance and protecting human and ecosystem health. Full article

This pilot study investigated the metabolic responses of five selected bacteria to physiological stress. Surface-enhanced Raman spectroscopy was used to analyze spectral changes associated with the release of adenine, a key metabolite indicative of stress conditions. Laboratory-synthesized spherical silver and gold nanoparticles, which remained stable over an extended period, were employed as enhanced surfaces. Bacterial cultures were analyzed under standard conditions and in the presence of a selected stressor—demineralized water—inducing osmotic stress. The results showed that the adenine signal originated from metabolites released into the surrounding environment rather than directly from the bacterial cell wall. The study confirms the suitability of these cost-effective and easily synthesized stable nanoparticles for the qualitative detection of bacterial metabolites using a commercially available Raman instrument. Full article

The excessive use of antimicrobials drives the emergence of multidrug resistance (MDR) in bacterial strains, which harbor resistance genes to survive under diverse drug pressures. Such resistance can result in life-threatening infections. The predominance of MDR Pseudomonas spp. poses significant challenges to public health and environmental sustainability, particularly in ecosystems affected by human activities. Characterizing MDR Pseudomonas spp. is crucial for developing effective diagnostic tools and biosecurity protocols, with broader implications for managing other pathogenic bacteria. Strains were diagnosed through 16S rRNA PCR and sequencing, complemented by phylogenetic analysis to evaluate local and global evolutionary connections. Antibiotic susceptibility tests revealed extensive resistance across multiple classes, with MIC values surpassing clinical breakpoints. This study examined the genetic diversity, resistance potential, and phylogenetic relationships among Pseudomonas aeruginosa strain DG2 and Pseudomonas fluorescens strain FM3, which were isolated from solid waste dump sites (n = 30) and dairy farms (n = 22) in West Bengal, India. Phylogenetic analysis reveals distinct clusters that highlight significant geographic linkages and genetic variability among the strains. Significant biofilm production under antibiotic exposure markedly increased resistance levels. RAPD-PCR profiling revealed substantial genetic diversity among the isolates, indicating variations in their genetic makeup. In contrast, SDS-PAGE analysis provided insights into the protein expression patterns that are activated by stress, which are closely linked to MDR. This dual approach offers a clearer perspective on their adaptive responses to environmental stressors. This study underscores the need for vigilant monitoring of MDR Pseudomonas spp. in anthropogenically impacted environments to mitigate risks to human and animal health. Surveillance strategies combining phenotypic and molecular approaches are essential to assess the risks posed by resilient pathogens. Solid waste and dairy farm ecosystems emerge as critical reservoirs for the evolution and dissemination of MDR Pseudomonas spp. Full article

The spotted longbarbel catfish, Hemibagrus guttatus, a nationally protected Class II species in China, faces increasing threats from habitat degradation. Recently, the spotted longbarbel catfish has gained attention as a promising aquaculture species, not only for its premium flesh quality but also for its potential role in conservation through sustainable captive breeding programs. Ammonia nitrogen (ammonia-N) is a ubiquitous byproduct of intensive farming and serves as the primary environmental stressor confronting aquatic species. Elucidating the ammonia-N tolerance of spotted longbarbel catfish constitutes a critical prerequisite for its successful domestication, which is the aim of this study. We demonstrate that ammonia-N stress significantly decreases the survival rate of spotted longbarbel catfish and induces tissue damage, including gill lamella proliferation, hepatocyte blurring, and renal necrosis. Transcriptomic analysis revealed that ammonia-N stress promotes the expression of genes related to endoplasmic reticulum stress, heat-shock proteins, immune response, and apoptosis, while inhibiting antioxidant-related genes and Wnt-related genes. Enzymatic assays indicate that ammonia-N stress inhibits the activities of multiple antioxidant enzymes, including SOD, CAT, GSH, GSH-Px, and T-AOC. Microbiome analysis showed that ammonia-N stress altered the intestinal microbial community by increasing harmful bacteria (e.g., Vibrio and Aeromonas) and suppressing beneficial bacteria (e.g., Cetobacterium and Lactococcus). These findings highlight the comprehensive negative impacts of ammonia-N on the health of the spotted longbarbel catfish and provide a theoretical basis for optimizing aquaculture conditions to support the sustainable protection and domestication of the spotted longbarbel catfish. Full article

Drought, an increasingly prevalent climate stressor due to global warming, profoundly impacts agricultural systems, particularly the soil microbiome. Soil microorganisms are crucial for nutrient cycling, plant health, and ecosystem stability; however, drought-induced changes disrupt microbial community structure, function, and interactions with plants. This review synthesizes current knowledge on the effects of drought on soil microbiomes, with a focus on microbial diversity, resilience, and functional shifts in agricultural contexts. It highlights key microbial mechanisms underpinning plant drought tolerance, including symbioses with plant growth-promoting bacteria and fungi. Furthermore, it addresses knowledge gaps in the long-term effects of repeated drought events, microbial adaptations, and plant–soil feedback mechanisms. By advancing our understanding of drought–microbiome dynamics, this review aims to inform sustainable agricultural practices and resilience strategies to mitigate the adverse impacts of drought on crop productivity and ecosystem health. Full article

Background/Objectives: The porcine respiratory disease complex (PRDC) is a multifaceted, polymicrobial syndrome resulting from a combination of environmental stressors, primary infections (e.g., PRRSV) and secondary infectious agents (viruses and bacteria). PRDC causes severe lung pathology, leading to reduced performance, increased mortality rates, and higher production costs in the global pig industry. Our goal was to conduct a comprehensive study correlating both the anti-PRRSV immune response and 21 secondary infectious agents with PRDC severity. Methods: To this end, PRRSV-negative weaners were vaccinated with a PRRSV-2 MLV and put into a farm with a history of PRDC. Subsequently, anti-PRRSV cellular and antibody responses were monitored pre-vaccination, at 28 days post vaccination (dpv) and during PRDC outbreak (49 dpv). NanoString was used to quantify 21 pathogens within the bronchoalveolar lavage (BAL) at the time of necropsy (51 dpv). PRRSV-2 was present in 53 out of 55 pigs, and the other five pathogens (PCMV, PPIV, B. bronchiseptica, G. parasuis, and M. hyorhinis) were detected in BAL samples. Results: Although the uncontrolled settings of field trials complicated data interpretation, multivariate correlation analyses highlighted valuable lessons: (i) high weaning weight predicted animal resilience to disease and high weight gains correlated with the control of the PRRSV-2 field strain; (ii) most pigs cleared MLV strain within 7 weeks, and the field PRRSV-2 strain was the most prevalent lung pathogen during PRDC; (iii) all pigs developed a systemic PRRSV IgG antibody response which correlated with IgG and IgA levels in BAL; (iv) the induction of anti-field strain-neutralizing antibodies by MLV PRRSV-2 vaccination was both late and limited; (v) cellular immune responses were variable but included strong systemic IFN-γ production against the PRRSV-2 field strain; (vi) the most detected lung pathogens correlated with PRRSV-2 viremia or lung loads; (vii) within the six detected pathogens, two viruses, PRRSV-2 and PCMV, significantly correlated with the severity of the clinical outcome. Conclusions: While a simple and conclusive answer to the multifaceted nature of PRDC remains elusive, the key lessons derived from this unique study provide a valuable framework for future research on porcine respiratory diseases. Full article

Waterlogging is a critical abiotic stressor that significantly impacts plant growth. Plants under waterlogging stress release metabolic signals that recruit rhizosphere microorganisms and enhance stress resistance. However, the mechanisms through which the non-adaptive species R. delavayi responds to waterlogging stress via the synergistic interaction between root metabolites and rhizosphere microbiota remain poorly elucidated. Here, we employed pot experiments to characterize the responses of the root metabolite–microbiota complex in R. delavayi during waterlogging stress and subsequent recovery. Our results revealed that waterlogging altered the root morphology, the root metabolite profile, rhizosphere microbial diversity and network complexity, and these effects persisted during recovery. A significant correlation between root metabolites and the rhizosphere microbial community structure during waterlogging stress and recovery. Importantly, some differentially accumulated metabolites had significant effects on the assembly of rhizosphere microbes. Most of the core microbes in the rhizosphere microbial community under waterlogging and post–waterlogging recovery treatment were likely beneficial bacteria. Based on these findings, we propose a model for how root metabolites and rhizosphere microbes interact to help R. delavayi cope with waterlogging and recover. Based on these findings, we propose a possible response pattern of root metabolites and rhizosphere microbiota complex in R. delavayi under waterlogging stress and recovery. This work provides new insights into the synergistic mechanisms enhancing plant waterlogging tolerance and highlights the potential of harnessing rhizosphere microbiota to improve resilience in rhododendrons. Full article

Plant microbiomes, composed of a diverse array of microorganisms such as bacteria, fungi, archaea, and microalgae, are critical to plant health and resilience, playing key roles in nutrient cycling, stress mitigation, and disease resistance. Climate change is expected to intensify various abiotic stressors, such as drought, salinity, temperature extremes, nutrient deficiencies, and heavy metal toxicity. Plant-associated microbiomes have emerged as a promising natural solution to help mitigate these stresses and enhance agricultural resilience. However, translating laboratory findings into real-world agricultural benefits remains a significant challenge due to the complexity of plant–microbe interactions under field conditions. We explore the roles of plant microbiomes in combating abiotic stress and discuss advances in microbiome engineering strategies, including synthetic biology, microbial consortia design, metagenomics, and CRISPR-Cas, with a focus on enhancing their practical application in agriculture. Integrating microbiome-based solutions into climate-smart agricultural practices may contribute to long-term sustainability. Finally, we underscore the importance of interdisciplinary collaboration in overcoming existing challenges. Microbiome-based solutions hold promise for improving global food security and promoting sustainable agricultural practices in the face of climate change. Full article

Seed quality is vital for agricultural productivity, as it directly influences the crop yield and resilience to environmental stressors. This study evaluated the effectiveness of a pulsed electric field (PEF) treatment in enhancing the tomato (Solanum lycopersicum) seed quality, seedling growth, and microbial safety. Tomato seeds were treated with PEFs at energy levels ranging from 1.07 to 17.28 J, and several parameters were assessed, including the germination rate, normal seedling development, tolerance to cold and salinity stress, electrical conductivity, and microbial inactivation. The highest germination rate (72.81%) was observed at 15.36 J on the seventh day of germination, whereas the highest normal seedling rate (94.62%) was recorded at 17.28 J (p ≤ 0.05). The germination under cold stress (5 days at 24 °C) was highest, with a 46.67% germination observed at both 1.92 and 10.88 J. PEF-treated seeds exposed to 100 and 200 mM of NaCl exhibited significantly improved germination compared to the controls (p ≤ 0.05). The electrical conductivity (EC) was more influenced by the incubation time than by the PEF intensity, as the EC of all samples showed a significant increase from 4 to 8 h. The samples treated with 17.28 J exhibited the highest germination rates under salt stress, reaching 62.00 ± 0.90% and 50.00 ± 0.60% under 100 mM and 200 mM of NaCl, respectively (p ≤ 0.05). The initial mean counts of the total mesophilic aerobic bacteria and the total mold and yeast—4.00 ± 0.03 and 3.06 ± 0.03 log cfu/g, respectively—were reduced to undetectable levels by the application of 17.28 J, with higher energy levels yielding greater inactivation. These findings demonstrate that the PEF is a promising technique for enhancing seed quality, promoting seedling vigor, and reducing microbial contamination, supporting its application in sustainable agriculture. Full article

Leucaena leucocephala (Lam.) de Wit is listed in the world’s 100 worst alien invasive species because of the risks it poses to native plant communities. Life history traits, such as high growth and reproductive rates, and a high capacity to adapt to different environmental conditions may contribute to its invasive properties. Biotic stressors, such as herbivores, pathogens, and competing plant species are known to exert significant selective pressure on the plant’s survival, distribution, and abundance. L. leucocephala has been reported to contain several compounds involved in the defense functions against these biotic stressors. A large amount of L-mimosine, a non-protein amino acid, was found in all plant parts of L. leucocephala, including its flowers. L-Mimosine is toxic to herbivorous mammals and insects, parasitic nematodes, pathogenic fungi, and neighboring competing plant species by inactivating various essential enzymes and blocking DNA replication, and/or inducing oxidative stress conditions. Several flavonoids, polyphenolic compounds, and/or derivatives of benzoic and cinnamic acids are toxic to parasitic nematodes, pathogenic fungi and bacteria, and competing plant species by disrupting plasma membrane structures and functions, and various metabolic processes. These compounds may represent the invasive traits of L. leucocephala that have undergone natural selection during the evolution of the species. They may contribute to the defense functions against the biotic stressors, and increase its survival, distribution, and abundance in the introduced ranges. This is the first review to focus on the compounds involved in the defense functions against biotic stressors. Full article

Tardigrades, also known as “water bears”, are microscopic invertebrates capable of surviving extreme conditions, including extreme temperatures, intense radiation, and the vacuum of space. Recent studies have unveiled a novel nucleosome-binding protein in the tardigrade Ramazzottius varieornatus, known as the damage suppressor protein (Dsup). This protein has proven essential for enabling tardigrades to thrive in the most challenging environmental conditions, highlighting its pivotal role in their remarkable survival capabilities. Dsup is a highly disordered protein with DNA-binding abilities that reduces DNA damage and enhances cell survival and viability caused by several stresses such as oxidative stress, UV exposure, and X-ray and ionizing radiation. In this review, we summarized articles describing the protective role of Dsup upon different stressors across diverse organisms, including bacteria, yeast, plants, and animals (cell lines and organisms). The multifaceted properties of Dsup open avenues for biotechnological applications, such as developing stress-resistant crops and innovative biomaterials for DNA manipulation. Furthermore, investigations into its potential in space exploration, particularly in protecting organisms from space radiation, underscore its relevance in extreme environments. Full article

Antimicrobial resistance (AMR) has emerged as a critical global public health threat, exacerbating healthcare burdens and imposing substantial economic costs. Currently, AMR contributes to nearly five million deaths annually worldwide, surpassing mortality rates of any single infectious disease. The economic burden associated with AMR-related disease management is estimated at approximately $730 billion per year. This review synthesizes current research on the mechanisms and multifaceted drivers of AMR development and dissemination through the lens of the One Health framework, which integrates human, animal, and environmental health perspectives. Intrinsic factors, including antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs), enable bacteria to evolve adaptive resistance mechanisms such as enzymatic inactivation, efflux pumps, and biofilm formation. Extrinsic drivers span environmental stressors (e.g., antimicrobials, heavy metals, disinfectants), socioeconomic practices, healthcare policies, and climate change, collectively accelerating AMR proliferation. Horizontal gene transfer and ecological pressures further facilitate the spread of antimicrobial-resistant bacteria across ecosystems. The cascading impacts of AMR threaten human health and agricultural productivity, elevate foodborne infection risks, and impose substantial economic burdens, particularly in low- and middle-income countries. To address this complex issue, the review advocates for interdisciplinary collaboration, robust policy implementation (e.g., antimicrobial stewardship), and innovative technologies (e.g., genomic surveillance, predictive modeling) under the One Health paradigm. Such integrated strategies are essential to mitigate AMR transmission, safeguard global health, and ensure sustainable development. Full article

Seagrass meadows play a critical role in biogeochemical cycling, especially in nitrogen and sulphur processes, driven by their associated microbiome. This study provides a novel functional analysis of microbial communities in seagrass (Zostera marina) rhizosphere and endosphere, comparing seedlings and mature plants. While nitrogen-fixing bacteria are more abundant in seedlings, mature plants exhibit greater microbial diversity and stability. Sediment samples show higher microbial diversity than roots, suggesting distinct niche environments in seagrass roots. Key microbial taxa (sulphur-oxidizing and nitrogen-cycling bacteria) were observed across developmental stages, with rapid establishment in seedlings aiding survival in sulphide-rich, anoxic sediments. Chromatiales, which oxidize sulphur, are hypothesized to support juvenile plant growth by mitigating sulphide toxicity, a key stressor in early development. Additionally, sulfate-reducing bacteria (SRB), though potentially harmful due to H₂S production, may also aid in nitrogen fixation by producing ammonium. The study underscores the dynamic relationship between seagrass and its microbiome, especially the differences in microbial community structure and function between juvenile and mature plants. The study emphasizes the need for a deeper understanding of microbial roles within the seagrass holobiont to aid with Blue Carbon stores and to improve restoration success, particularly for juvenile plants struggling to establish effective microbiomes. Full article

Forest plantations in the Neotropics aim to alleviate pressure on primary forests. This study synthesizes knowledge on pine species used in these plantations, emphasizing the challenges and potential of ectomycorrhizal fungi and bacteria as inoculants. An analysis of 98 articles identifies 23 pine species in Mexico and Central America and about 16 fast-growing species in South America. While pine plantations provide a habitat for generalist species, they reduce the richness of specialist species. Ectomycorrhizal fungi and bacterial diversity in plantations with introduced pines is up to 20% lower compared to native ecosystems. Suillus and Hebeloma are commonly used as mycorrhizal inoculants for Neotropical and introduced species, including Pinus ponderosa and Pinus radiata in South America. Commercial inoculants predominantly feature the fungal species Pisolithus tinctorius, alongside bacterial genera such as Bacillus, Cohnella, and Pseudomonas. This study emphasizes the importance of leveraging native microbial communities and their synergistic interactions with ECM fungi and bacteria to enhance seedling growth and quality. Such a combined approach can improve plantation survival, boost resilience to environmental stressors, and promote long-term productivity. These findings underscore the need to incorporate native fungi and bacteria into inoculant strategies, advancing sustainable forestry practices and ecosystem adaptation in the Neotropics. Full article

Feather pecking (FP) is a significant welfare and economic problem in laying hen husbandry. While there is growing evidence that the glutamatergic system plays a crucial role in regulating FP behavior, the biological mechanisms remain unclear, largely due to the limited uptake of peripheral glutamate across the blood–brain barrier (BBB). Here, we applied a multi-omics approach combined with physiology assays to answer this question from the perspective of the gut–brain axis. A total of 108 hens were randomly assigned to two groups (treatment and control) with six replicates each, and the treatment group was subjected to chronic environmental stressors including re-housing, noise, and transport. We found that chronic exposure to environmental stressors induced severe FP, accompanied by reduced production performance and increased anxiety- and depression-related behaviors, compared to controls. In addition, the immune system was potentially disrupted in FP chickens. Notably, gut microbiota diversity and composition were significantly altered, leading to decreased microbial community stability. Non-targeted metabolomic analysis identified a variety of differential metabolites, primarily associated with arginine and histidine biosynthesis. A significant increase in glutamate levels was also observed in the hippocampus of FP chickens. Transcriptome analysis revealed the upregulated expressions of glutamate-related receptors GRIN2A and SLC17A6 in the hippocampus. Correlation analysis indicated that GRIN2A and SLC17A6 are positively associated with arginine levels in the duodenum, while Romboutsia in the duodenum is negatively correlated with arginine. These findings suggest that intestinal bacteria, including Romboutsia, may influence FP behavior by altering plasma arginine and histidine levels. These changes, in turn, affect glutamate levels and receptor gene expression in the hippocampus, thereby regulating the glutamatergic system. Our research offers insights into novel strategies for mitigating harmful behaviors in poultry farming, with potential benefits for animal performance and welfare. Full article