Explore the vast range of titles available.

Hybridization between organisms from evolutionarily distinct lineages can have profound consequences on organismal ecology, with cascading effects on fitness and evolution. Most studies of hybrid organisms have focused on organismal traits, for example, various aspects of morphology and physiology. However, with the recent emergence of holobiont theory, there has been growing interest in understanding how hybridization impacts and is impacted by host‐associated microbiomes. Better understanding of the interplay between host hybridization and host‐associated microbiomes has the potential to provide insight into both the roles of host‐associated microbiomes as dictators of host performance as well as the fundamental rules governing host‐associated microbiome assembly. Unfortunately, there is a current lack of frameworks for understanding the structure of host‐associated microbiomes of hybrid organisms. In this paper, we develop four conceptual models describing possible relationships between the host‐associated microbiomes of hybrids and their progenitor or ‘parent’ taxa. We then integrate these models into a quantitative ‘4H index’ and present a new R package for calculation, visualization and analysis of this index. We demonstrate how the 4H index can be used to compare hybrid microbiomes across disparate plant and animal systems. Our analyses of these data sets show variation in the 4H index across systems based on host taxonomy, host site and microbial taxonomic group. Our four conceptual models, paired with our 4H index and associated visualization tools, facilitate comparison across hybrid systems. This, in turn, allows for systematic exploration of how different aspects of host hybridization impact the host‐associated microbiomes of hybrid organisms.

The commercial aquatic animal microbiome may markedly affect the successful host's farming in various aquaculture systems. However, very little was known about it. Here, two different aquaculture systems, the rice–fish culture (RFC) and intensive pond culture (IPC) systems, were compared to deconstruct the skin, oral, and gut microbiome, as well as the gut metabolome of juvenile Chinese softshell turtle (Pelodiscus sinensis). Higher alpha‐diversity and functional redundancy of P. sinensis microbial community were found in the RFC than those of the IPC. The aquaculture systems have the strongest influence on the gut microbiome, followed by the skin microbiome, and finally the oral microbiome. Source‐tracking analysis showed that the RFC's microbial community originated from more unknown sources than that of the IPC across all body regions. Strikingly, the RFC's oral and skin microbiome exhibited a significantly higher proportion of generalists and broader habitat niche breadth than those of the IPC, but not the gut. Null model analysis revealed that the RFC's oral and skin microbial community assembly was governed by a significantly greater proportion of deterministic processes than that of the IPC, but not the gut. We further identified the key gene and microbial contribution to five significantly changed gut metabolites, 2‐oxoglutarate, N‐acetyl‐d‐mannosamine, cis‐4‐hydroxy‐d‐proline, nicotinamide, and l‐alanine, which were significantly correlated with important categories of microbe‐mediated processes, including the amino acid metabolism, GABAergic synapse, ABC transporters, biosynthesis of unsaturated fatty acids, as well as citrate cycle. Moreover, different aquaculture systems have a significant impact on the hepatic lipid metabolism and body shape of P. sinensis. Our results provide new insight into the influence of aquaculture systems on the microbial community structure feature and assembly mechanism in an aquatic animal, also highlighting the key microbiome and gene contributions to the metabolite variation in the gut microbiome‐metabolome association. In brief, different aquaculture system induces distinct tissue‐specific microbiome assembly that alters host fitness in part through gut metabolites. Highlights Different aquaculture system induces distinct phenotype, microbiome assembly, and gut metabolome. In brief, different aquaculture system induces distinct tissue‐specific microbiome assembly that alters host fitness in part through gut metabolites. Distinct microbial diversity and community structure are driven through different sources and community assembly processes. To identify several key genes and microbial species that contribute to five significantly changed gut metabolites.

California's Channel Islands are home to two endemic mammalian carnivores: island foxes (Urocyon littoralis) and island spotted skunks (Spilogale gracilis amphiala). Although it is rare for two insular terrestrial carnivores to coexist, these known competitors persist on both Santa Cruz Island and Santa Rosa Island. We hypothesized that examination of their gut microbial communities would provide insight into the factors that enable this coexistence, as microbial symbionts often reflect host evolutionary history and contemporary ecology. Using rectal swabs collected from island foxes and island spotted skunks sampled across both islands, we generated 16S rRNA amplicon sequencing data to characterize their gut microbiomes. While island foxes and island spotted skunks both harbored the core mammalian microbiome, host species explained the largest proportion of variation in the dataset. We further identified intraspecific variation between island populations, with greater differentiation observed between more specialist island spotted skunk populations compared to more generalist island fox populations. This pattern may reflect differences in resource utilization following fine‐scale niche differentiation. It may further reflect evolutionary differences regarding the timing of intraspecific separation. Considered together, this study contributes to the growing catalog of wildlife microbiome studies, with important implications for understanding how eco‐evolutionary processes enable the coexistence of terrestrial carnivores–and their microbiomes–in island environments. We examined the host‐associated microbiome of Channel Island foxes and island spotted skunks in the context of fine‐scale niche differentiation, as it is rare for two endemic, insular mesocarnivores to coexist. We found intraspecific variation between island populations, with greater differentiation observed between more specialist island spotted skunk populations compared to more generalist island fox populations. This pattern may reflect differences in resource utilization following fine‐scale niche differentiation, as well as evolutionary differences regarding the timing of intraspecific separation.

In human-altered landscapes, animals face numerous threats to their survival, yet little is known about how rapid environmental change affects host–microbiome dynamics across generations. Microbial communities play critical roles in host nutrition, immunity, and overall fitness, and shifts in composition may alter an organism’s ability to adapt. We examined the gut microbiota of the endangered Pacific pocket mouse during the transition from wild to captive environments and across four descendant generations. We found that the microbiome did not immediately shift with captivity but instead stabilized into a distinct, captivity-associated state only after several generations. This study provides the first characterization of gut microbiota in pocket mice and is the first to show, at this resolution, how a wildlife species’ microbiome adapts to environmental change while tracking health and fitness across generations. Our findings highlight the need to incorporate microbiome dynamics into conservation breeding and management strategies.

HMA mice are models that better represent human gut ecology compared to conventional laboratory mice and are commonly used to test the effects of the gut microbiome on disease or treatment response. We evaluated the fidelity of using HMA mice as avatars of ecological response to a human microbial consortium, Microbial Ecosystem Therapeutic 4. Our results show that HMA mice in our cohort and across other published studies are more similar to each other than the human donors or inoculum they are derived from and harbor a taxonomically restricted gut microbiome. These findings highlight the limitations of HMA mice in evaluating the ecological effects of complex human microbiome-targeting interventions, such as microbial consortia.

The interplay between diet and the gut microbiome is fundamental to shaping host physiology and behavior; however, their interactions remain poorly understood. Most studies treat diet as a single-dimensional variable (e.g., high-fat or high-sugar), overlooking the complexity of nutrient balance and density. This oversimplification neglects how diet and microbes function as an integrated system. This study addresses this gap by testing 120 different nutrient-microbiome combinations in Drosophila melanogaster , systematically varying yeast and carbohydrate levels and microbiome configurations. Our results show that dietary nutrient composition drives body protein and fat storage, whereas the microbiome plays a notable role in glucose metabolism and buffers against excess fat accumulation. Microbial effects on reproduction, locomotion, and sleep depend on nutrient composition, and our model reveals specific diet-microbiome patterns driving these outcomes. By treating diet as a dynamic, multidimensional factor, we provide a novel, ecologically relevant framework for understanding how diet and microbiome shape host.

is among the most abundant bacterial genera in the healthy human colon, comprising approximately 10-15% of the total gut microbiota. Species within this genus ferment complex carbohydrates, including pectin, to produce butyrate, a short-chain fatty acid with anti-inflammatory and anti-carcinogenic properties. Butyrate is the primary energy source for colonocytes and in is synthesized via the butyryl-CoA:acetate CoA transferase pathway. Reduced levels of are often associated with increased abundance of and may be linked to early-onset colorectal cancer. Here, genomic analysis of strains revealed that several lack antibiotic resistance genes, suggesting a favorable safety profile. Additional genome mining revealed multiple biosynthetic gene clusters (BGCs) involved in the synthesis of secondary metabolites, including ranthipeptides, which may exhibit antimicrobial activity. Understanding the functional roles of these BGCs, particularly their potential to inhibit , is critical for advancing microbiome-based therapies. Moreover, developing effective delivery strategies to maintain populations in the colon is essential for promoting gut health and preventing disease.

Gut microbial metabolic activities play important roles in human health, prompting interest in the discovery of gut microbiome-targeted small molecule inhibitors as potential therapeutics. Anaerobic choline metabolism by the gut microbiome generates trimethylamine and its downstream metabolite trimethylamine- N -oxide (TMAO), which cause trimethylaminuria and are correlated with cardiometabolic diseases, respectively. Current strategies for modulating microbial metabolism with small molecule inhibitors typically require having a target enzyme. Here, we show that a growth-based phenotypic screen can identify inhibitors of choline metabolism with chemical scaffolds that are structurally distinct from choline and existing inhibitors. The resulting optimized compounds lower serum TMAO in gnotobiotic mice without significantly perturbing gut microbiome composition. This work highlights the potential of using phenotypic screening to rapidly discover additional inhibitors of microbial metabolic activities, which would accelerate mechanistic studies of the microbiome and deepen our understanding of disease biology from correlation to causation.

Microorganisms play a fundamental role in human health, contributing to digestion, immune regulation, and metabolic processes. While direct colonization by environmental microbes through ingestion, inhalation, and dermal contact has been documented, evidence suggests that multisensory interactions with nature-via visual, auditory, tactile, gustatory, and olfactory stimuli-also influence the gut microbiome through psychophysiological and immune-mediated pathways. Exposure to natural environments can regulate stress and immune responses, activate the parasympathetic nervous system, and modulate the hypothalamic-pituitary-adrenal and gut-brain axes, which in turn may alter gut microbiome composition and function. Furthermore, sensory interactions with nature may induce epigenetic changes that impact immune function and microbiome dynamics over time. Here, we review evidence for nature-based indirect shaping of the human microbiome (including multisensory and exposure-immunoregulation pathways) and suggest that after the early-life critical window of microbiome development (0-3 years), these indirect effects likely have a greater influence on gut microbiome dynamics than direct colonization by environmental microbiota (e.g., ingested directly from the air). However, this concept remains to be comprehensively tested. Therefore, understanding the relative contributions of direct microbial colonization versus indirect effects-such as multisensory stimulation and immune modulation-demands more integrated, transdisciplinary research. Integrating these insights into public health strategies, urban design, and nature-based interventions could promote microbiome eubiosis, ultimately improving human (and non-human animal) well-being in an era of increasing environmental and health challenges.

This study provides the first comprehensive analysis of gut microbiome development in Icelandic children, covering the time from before the introduction of solid foods to 5 years of age. Although the overall developmental patterns of the gut microbiome in Icelandic children were similar to what has been seen in other studies, interesting differences were observed, such as a higher abundance of Blautia at an earlier age compared to other study populations. Higher alpha diversity in archaeal-positive samples, both in mothers and in children at the ages of 2 and 5, compared with archaeal-negative samples seen in the present study, is worth further investigation. Additionally, the study suggests a potential role of maternal and perinatal factors, particularly GDM, which was not evident until the age of 5 years, emphasizing the necessity of long-term studies.