Search Results (128)

Microbial infections are an escalating global health threat, driven by the alarming rise of antimicrobial resistance (AMR), which has made many conventional antibiotics increasingly ineffective and threatens to reverse decades of medical progress. The rapid emergence and spread of multidrug-resistant bacteria have severely limited treatment options, resulting in increased morbidity, mortality, and healthcare burden worldwide. In response to these challenges, phage therapy is regaining interest as a promising alternative. Bacteriophages, the most abundant biological entities, have remarkable specificity toward their bacterial hosts, enabling them to selectively eliminate pathogenic strains. Phage therapy presents several advantages over conventional antibiotics, which include minimal disruption to the microbiome and a slower rate of resistance development. Among the various sources of phages, the marine environment remains one of the least explored. Given their adaptation to saline conditions, high pressure, and variable nutrient levels, marine bacteriophages mostly exhibit enhanced environmental stability, broader host ranges, and distinct infection mechanisms, thus making them highly promising for therapeutic purposes. This review explores the growing therapeutic potential of marine bacteriophages by examining their ecological diversity, biological characteristics, infection dynamics, and practical applications in microbial disease control. It also deals with emerging strategies such as phage–antibiotic synergy, genetic engineering, and the use of phage-derived enzymes, alongside several challenges that must be addressed to enable clinical translation and regulatory approval. Advancing our understanding and application of marine phages presents a promising path in the global fight against AMR and the development of next-generation antimicrobial therapies. Full article

The greater amberjack (Seriola dumerili), a key species in marine aquaculture, relies heavily on its intestine for nutrient absorption and immune function. However, the structural and functional specialization of its intestinal segments remains poorly understood. In this study, we divided the intestine of S. dumerili into foregut, midgut, and hindgut, and conducted a multi-omics analysis integrating histological staining (H&E/AB-PAS), digestive enzyme assays, transcriptome sequencing, and 16S rRNA microbiota profiling to characterize structural, functional, molecular, and microbial differences across intestinal segments. Histological examinations revealed that brush border microvillus length, muscle layer thickness, and folding height were significantly greater in the foregut and hindgut compared to the midgut, while mucus and goblet cell density was higher in the foregut and midgut. Digestive enzyme assays showed that lipase activity peaked in the foregut, α-amylase in the midgut, and protease in the midgut and hindgut. Alkaline phosphatase (AKP) and acid phosphatase (ACP) activities were highest in the foregut and midgut. Immune-related enzyme activities (SOD (Superoxide dismutase), GSH-Px (Glutathione peroxidase), T-AOC (Total Antioxidant Capacity)) were elevated and MDA levels were lower in the midgut, indicating its role as the primary immune site. Transcriptome analysis identified segment-specific expression of nutrient transporters, such as slc6a19b (hindgut, protein), apoa1b (foregut, lipid), and slc37a4 (midgut, carbohydrate). Microbiome analysis revealed Ruminococcus dominance in the foregut (lipid digestion) and Prevotella, Bifidobacterium, and Lactobacillus enrichment in the midgut (carbohydrate metabolism and immunity). These findings highlight functional zonation in S. dumerili: the foregut specializes in lipid digestion, the midgut in carbohydrate metabolism and immunity, and the hindgut in protein digestion. This study provides foundational insights for optimizing aquaculture practices and advancing research in nutrition, immunology, and disease modeling in S. dumerili. Full article

The gut microbiome of sea turtles is essential for their ecological resilience and adaptation to environmental stressors. We hypothesised that different gut microbial profiles existed between green sea turtles kept in captivity and those in the wild. The aim of this systematic review was to determine dominant bacterial phyla in the gut microbiomes of wild and captive green sea turtles. Comparison of the top four bacterial phyla revealed that Bacillota was the most abundant phylum in captive turtles (40.9–87.5%), but it only ranked second (3.5–57.8%) in wild turtles. Bacteroidota had comparable relative abundance in captive (8.7–45.6%) and wild (3.6–43.1%) populations. By contrast, the relative abundance of Pseudomonadota was higher in wild turtles (6.2–68.1%) compared to the captive population (0.1–6.6%). Verrucomicrobiota was less prevalent in wild and captive populations, with relative abundances ranging from 0.28 to 5.4% and 2.3 to 7.2%, respectively. These findings highlight a putative gut microbial shift between wild and captive green sea turtle populations. This shift may be shaped by variations in environmental factors in captivity or the wild. Nonetheless, the significance of these putative changes is still unknown; the potential to use microbial shifts to guide management, rehabilitation, and conservation of green sea turtles is promising, but remains limited. 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

Cardiovascular diseases (CVDs), including heart failure (HF), hypertension, myocardial infarction (MI), and atherosclerosis, are increasingly linked to gut microbiota dysbiosis and its metabolic byproducts. HF, affecting over 64 million individuals globally, is associated with systemic inflammation and gut barrier dysfunction, exacerbating disease progression. Similarly, hypertension and MI correlate with reduced microbial diversity and an abundance of pro-inflammatory bacteria, contributing to vascular inflammation and increased cardiovascular risk. Atherosclerosis is also influenced by gut dysbiosis, with key microbial metabolites such as trimethylamine-N-oxide (TMAO) and short-chain fatty acids (SCFAs) playing crucial roles in disease pathogenesis. Emerging evidence highlights the therapeutic potential of natural compounds, including flavonoids, omega-3 fatty acids, resveratrol, curcumin, and marine-derived bioactives, which modulate the gut microbiota and confer cardioprotective effects. These insights underscore the gut microbiota as a critical regulator of cardiovascular health, suggesting that targeting dysbiosis may offer novel preventive and therapeutic strategies. Further research is needed to elucidate underlying mechanisms and optimize microbiome-based interventions for improved cardiovascular outcomes. Full article

For marine bacteria, the phycosphere is attractive as a major source of labile nutrients, but it also presents challenges due to the accumulation of stressors, such as reactive oxygen species (ROS) from algal metabolisms. Therefore, successful colonization of bacteria in the phycosphere requires an efficient mechanism to fight against oxidative stress, which is still a missing piece in studying bacteria–algae interactions. Here, we demonstrate that a common metabolite, indole acetic acid (IAA), enables the Roseobacter clade Sulfitobacter mediterraneus SC1-11, an IAA-producer, to resist hydrogen peroxide (H₂O₂) stress and that IAA biosynthesis can be activated by low concentrations of H₂O₂. Proteomics and metabolomics analyses revealed that bacteria consume high amino acid levels when exposed to H₂O₂ stress, while exogenous supplementation with IAA effectively protects bacteria from ROS damage and alleviates amino acid starvation by upregulating several proteins responsible for replication, recombination, and repair, as well as two proteins involved in amino acid transport and metabolism. Furthermore, the supplementation of some amino acids, such as arginine, also showed a significant protective effect on bacteria under H₂O₂ stress. This study highlights an unprecedented role of IAA in regulating amino acid metabolisms for resisting oxidative stress, which may be a specific strategy for adapting to the phycosphere. Full article

Microplastics have emerged as a pervasive marine contaminant, with extreme concentrations reported in deep-sea sediments (e.g., 1.9 million particles/m²) and localized accumulations near Antarctic research stations. Particular concern has been raised regarding their synergistic effects with co-occurring antibiotics, which may potentiate toxicity and facilitate antibiotic resistance gene dissemination through microbial colonization of plastic surfaces. To investigate these interactions, a 185-day controlled exposure experiment was conducted using Aurelia aurita polyps. Factorial combinations of microplastics (0, 0.1, 1 mg/L) and tetracycline (0, 0.5, 5 mg/L) were employed to simulate environmentally relevant pollution scenarios. Microbiome alterations were characterized using metagenomic approaches. Analysis revealed that while alpha and beta diversity measures remained unaffected at environmental concentrations, significant shifts occurred in the relative abundance of dominant bacterial taxa, including Pseudomonadota, Actinomycetota, and Mycoplasmatota. Metabolic pathway analysis demonstrated perturbations in key functional categories including cellular processes and environmental signal transduction. Furthermore, microplastic exposure was associated with modifications in polyp life-stage characteristics, suggesting potential implications for benthic–pelagic population dynamics. These findings provide evidence for the impacts of microplastic–antibiotic interactions on cnidarian holobionts, with ramifications for predicting jellyfish population responses in contaminated ecosystems. Full article

Environmental temperature declines significantly impact the physiological processes of marine organisms, particularly under the cool La Nina conditions, challenging yellowfin tuna (Thunnus albacares) aquaculture. Low temperatures affect fish metabolism and immune functions and can alter the gut microbiota composition, influencing health and growth. This study investigates the impact of low temperatures on the gut microbiota of juvenile yellowfin tuna. Fish were divided into a Low Temperature (LT) group (24 °C), an Ultra Low Temperature (ULT) group (18 °C), and a Control group (CG) (30 °C), with evaluations at 0, 12, 24, and 36 h using α-diversity analysis and microbial species composition. Results indicated a significant increase in the Ace index for the ULT group after 36 h of cold stress (p < 0.05), with no significant changes in the Shannon index. A decline in Proteobacteria and increases in Verrucomicrobiota and Firmicutes were observed in both LT and ULT groups. Additionally, both LT and ULT groups showed a significant rise in the Ace index at 36 h (p < 0.05), with a significant decrease in the Shannon index in the ULT group at 24 h. Furthermore, Firmicutes significantly increased at 12 h in both temperature groups (p < 0.05). These findings highlight the potential role of the gut microbiome in adapting yellowfin tuna to cold environments and provide microbial insights into their physiological adaptations, laying a foundation for further research and practical applications in aquaculture under cold conditions. Full article

Sustainably farmed Atlantic salmon could drive global food system solutions by contributing essential nutrients to the human diet while delivering high-quality protein. One of the biggest obstacles to sustainable salmon aquaculture in Chile is the prevalence of piscirickettsiosis disease caused by the Gram-negative bacteria Piscirickettsia salmonis and the excessive amount of antibiotics used to eradicate this disease. Farmed salmon products can be consumed without prior processing and therefore present a substantial risk for the transfer of resistant pathogens to humans. Antibiotics also carry the risk of antibiotic residues and damage to the environment. An alternative to antibiotics is the use of natural antimicrobials without the negative influence on the consumer’s microbiome. Here, we evaluate the potential antimicrobial activity against P. salmonis of the marine microalgae Microchloropsis gaditana. A non-genetically modified M. gaditana was grown with nitrogen deprivation to improve the synthesis of the eicosapentaenoic fatty acid (EPA). A spray-dried M. gaditana concentrate (Mg) was elaborated and given to Atlantic salmon for a period of 49 days, and serum and fillet samples were collected. Our results showed a significant increase in the nutritional quality improving the levels of EPA+ Docosapentaenoic acid (DPA) (23%) and Vitamin D₃ (106%) of the fillets treated with Mg. Fish fed serum were challenged with P. salmonis, and serum antibacterial activity was measured. Sera from fish fed Mg-enriched diets showed a significant increase in antibacterial activity (85.68%) against P. salmonis. Our results indicate that Mg can be used as a viable alternative to address the critical problem of microbial resistance and to assure consumers that farm-raised Atlantic salmon is safe. Full article

Sulfamethoxazole (SMX), a commonly used sulfonamide antibiotic, poses a threat to aquatic life due to its widespread presence in the environment. This study aims to investigate the specific effects of SMX on the development of marine medaka (Oryzias melastigma) embryos and larvae. Marine medaka embryos were exposed to SMX at concentrations of 0 (solvent control group, SC group), 1 μg/L (low concentration group, L group), 60 μg/L (middle concentration group, M group), and 1000 μg/L (high concentration group, H group). The results indicated that SMX exposure significantly accelerated the heart rate of embryos (p < 0.0001) and shortened the hatching time while also causing anomalies such as reduced pigmentation, smaller eye size, spinal curvature, and yolk sac edema. SMX also led to a decrease in the total length of the larvae. The M group and the H group exhibited a significant increase (p < 0.05) in lipid accumulation in the visceral mass of the larvae. In the L group and the M group, there was a significant increase (p < 0.0001) in the swimming distance of the larvae. At the molecular level, SMX exposure affected the transcript levels of the genes involved in the cardiovascular system (ahrra, arnt2, atp2a1, and cacan1da), antioxidant and inflammatory systems (cat, cox-1, gpx, pparα, pparβ, and pparγ), nervous system (gap43, gfap, α-tubulin), intestinal barrier function (claudin-1), detoxification enzymes (ugt2c1-like), and lipid metabolism (rxraa) in the embryos to larval stage. The microbiome analysis showed that at the phylum level, exposure to SMX resulted in an increase in the abundance of Proteobacteria. Additionally, the abundance of Actinobacteriota significantly increased in the L group (p < 0.05). At the genus level, the abundance of Bifidobacterium significantly increased in the L group (p < 0.05), while the abundance of Vibrio significantly increased in the H group (p < 0.05). The alpha diversity analysis revealed a significant decrease in the Chao1 index in the L and H groups, indicating a reduction in microbial richness. The beta diversity analysis showed differences in the microbial communities of marine medaka larvae among different SMX exposure groups. This study elucidates the negative impacts of SMX on the development of marine medaka embryos and larvae and their microbial composition, providing a scientific basis for assessing the risks of SMX in marine ecosystems. Full article

Microplastics (MPs), defined as plastic particles smaller than 5 mm, have emerged as a global environmental and public health crisis, infiltrating air, water, soil, and food systems worldwide. MPs originate from the breakdown of larger plastic debris, single-use plastics, and industrial processes, entering food. Emerging evidence underscores the ability of MPs to cross biological barriers, including the blood–brain barrier, triggering neuroinflammatory responses and contributing to neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Polystyrene (PS), a common type of MP, activates microglial cells, releasing pro-inflammatory cytokines like tumor necrosis factor (TNF-α) and interleukins, which increase neuronal damage. MPs have also been linked to cardiovascular diseases, with studies detecting polyethylene (PE) and polyvinyl chloride (PVC) in carotid artery plaques, increasing the risk of myocardial infarction and stroke. Furthermore, MPs disrupt endocrine function, alter lipid metabolism, and induce gut microbiome imbalances, posing multifaceted health risks. In the MENA region, MP pollution is particularly severe, with the Mediterranean Sea receiving an estimated 570,000 tons of plastic annually, equivalent to 33,800 plastic bottles per minute. Studies in Egypt, Lebanon, and Tunisia document high MP concentrations in marine ecosystems, with herbivorous fish like Siganus rivulatus containing over 1000 MPs per individual due to the ingestion of contaminated seaweed. Despite these findings, public awareness and regulatory frameworks remain inadequate, with only 24% of Egyptians demonstrating sufficient knowledge of safe plastic use. This review emphasizes the urgent need for region-specific research, policy interventions, and public awareness campaigns to address MP pollution. Recommendations include sustainable waste management practices, the promotion of biodegradable alternatives, and enhanced monitoring systems to mitigate the health and environmental impacts of MPs in the MENA region. Full article

The holobiome is an interconnected network of microbial ecosystems spanning soil, plants, animals, humans, and the environment. Microbial interactions drive nutrient cycling, pathogen suppression, and climate regulation. Soil microbiomes facilitate carbon sequestration and enhance soil fertility, while marine microbiomes contribute to carbon capture and climate stability. However, industrial agriculture, extensive herbicide use, antibiotic overuse, and climate change threaten microbial diversity, leading to ecosystem and health disruptions. Probiotic interventions help to restore microbial balance. In human health, probiotics support gut microbiota diversity, reduce inflammation, and regulate metabolism. In agriculture, soil probiotics enhance microbial diversity, improve nutrient cycling, and degrade contaminants, increasing crop yields and soil health. Case studies show that microbial inoculants effectively remediate degraded soils and enhance nutrient uptake. Artificial intelligence is transforming microbiome research by enabling predictive modeling, precision probiotic design, and microbial consortia optimization. Interdisciplinary collaboration and supportive policies are essential for restoring microbial equilibria, ensuring ecosystem resilience, and promoting long-term sustainability. The integration of artificial intelligence, clinical research, and sustainable practices is crucial for advancing holobiome science. The holobiome framework underscores the need for interdisciplinary collaboration to address global challenges, bridging environmental sustainability, agriculture, and public health for a resilient future. Full article

Birds, fish, and marine mammals consumed by indigenous people are included in Arctic biomonitoring. However, there are still many gaps in the data on the microbiota associated with these animals. In the current study, we used high-throughput 16S rRNA gene sequencing to explore the bacterial diversity and composition in the intestines of willow ptarmigans, greater white-fronted geese, and taiga bean geese, which are widely consumed by indigenous people in the Arctic. For the first time, meta-taxonomic data have been obtained on the lungs of wild resident and migratory birds of the Russian North. The potentially pathogenic bacterial genera Helicobacter and Olsenella were found in the intestinal microbiomes of three bird species and in the lungs of willow ptarmigan. Bacteria of the genus Staphylococcus were individually identified in the intestines of willow ptarmigan, Campylobacter sp. in the intestines of taiga bean goose, and Sutterella sp. in the intestines of greater white-fronted goose as potential pathogens. The primary findings will be used to propose a next-generation sequencing scheme for monitoring both chemical and biological contaminants in the Arctic in line with One Health approach. Full article

Background/Objectives: Ulcerative colitis (UC), a chronic inflammatory bowel disease (IBD), is characterized by colorectal immune infiltration and significant microbiota compositional changes. Gut microbiota homeostasis is necessary to maintain the healthy state of humans. MR2938, a quinazolin-4(3H)-one derivative derived from the marine natural product penipanoid C, alleviated DSS-induced colitis in a dose-dependent manner. Herein, we aimed to investigate the impact of MR2938 on the gut microbiota in dextran sodium sulfate (DSS)-induced colitis in mice and to elucidate the role of the gut microbiota in the therapeutic mechanism of MR2938 for alleviating colitis. Methods: Acute colitis was induced with DSS in mice. Mice were administered with 100 mg/kg or 50 mg/kg of MR2938. Cecal content was also preserved in liquid nitrogen and subsequently analyzed following 16S RNA sequencing. Antibiotic cocktail-induced microbiome depletion was performed to further investigate the relationship between MR2938 and gut microbiota. The inflammatory factor levels were performed by quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay (ELISA). Alcian blue staining and immunofluorescence were used to estimate the intestinal barrier. Results: The 16S rRNA sequencing revealed microbiota modulation by MR2938. Compared with the model group, the 100 mg/kg MR2938 group was associated with higher abundances of Entercoccus and a lower abundance of Staphylococcus, while the 50 mg/kg MR2938 group was associated with higher abundances of Lactobacillus and a lower abundance of Staphylococcus. The antibiotic-mediated microbiota depletion experiments demonstrated that the gut microbiota primarily contributed to barrier function protection, with little impact on inflammatory factor levels during the MR2938 treatment. Conclusions: These findings suggest that intestinal flora play a crucial role in MR2938’s therapeutic mechanism for alleviating colitis. Full article

The impact of macroalgae species on rumen function remains largely unexplored. This present study aimed to identify the biocompounds of the three types of marine macroalgae described: Macrocystis pyrifera (Brown), Ulva spp. (Lettuce), Mazzaella spp. (Red) and their effect on species-specific modulations of the rumen microbiome. The macroalgae were characterized using GC-MS. Twelve Rambouillet lambs were randomly assigned to one of four experimental diets (n = 3 per treatment): (a) control diet (CD); (b) CD + 5 g of Red algae; (c) CD + 5 g of Brown algae; and (d) CD + 5 g of Lettuce algae. After the lambs ended their fattening phase, they donated ruminal fluid for DNA extraction and 16S rRNA gene V3 amplicon sequencing. Results: The tagged 16S rRNA amplicon sequencing and statistical analysis revealed that the dominant ruminal bacteria shared by all four sample groups belonged to phyla Firmicutes and Bacteroidota. However, the relative abundance of these bacterial groups was markedly affected by diet composition. In animals fed with macroalgae, the fibrinolytic and cellulolytic bacteria Selenomonas was found in the highest abundance. The diversity in chemical composition among macroalgae species introduces a range of bioactive compounds, particularly VOCs like anethole, beta-himachalene, and 4-ethylphenol, which demonstrate antimicrobial and fermentation-modulating properties. Full article