Porphyromonas gingivalis has long been recognized as a keystone pathogen associated with periodontal diseases and has more recently been implicated in systemic comorbidities beyond the oral cavity. However, amongst the oral microbiota, P. gingivalis has a distinctive relationship with the host, and despite possessing a repertoire of virulence factors, P. gingivalis colonization does not invariably result in adverse outcomes. Under specific ecological conditions and host immune or susceptibility states, P. gingivalis functions as a keystone pathogen, exerting an impact disproportionate to its abundance in the context of a complex polymicrobial community. Indeed, P. gingivalis-containing communities induce dysbiotic immune responses that lead to pathobiont expansion and inflammatory tissue destruction. Moreover, emerging evidence indicates that virulence in P. gingivalis is tunable in response to metabolite availability. Under nutritional limitation, cell-associated gingipain activity increases, conferring on P. gingivalis the potential to more aggressively degrade host tissues and thereby generate proteinaceous substrates for growth. In addition, P. gingivalis is adept at decoupling nutritionally favourable inflammatory responses from antimicrobial pathways. Ultimately, substrate availability and the host immune response re-equilibrate, and P. gingivalis once again becomes quiescent. In this Review, we discuss the mechanistic basis of contextual virulence regulation in P. gingivalis and its impact on host homeostasis and immune function. In this Review, Lamont and Hajishengallis explore how the pathogenicity of Porphyromonas gingivalis is determined by microbial, metabolic and host context. They discuss how community interactions, nutrient-sensing and immune subversion regulate virulence and drive dysbiosis, inflammation and periodontitis progression.
Marine microorganisms underpin primary production, biogeochemical cycling and host-associated symbioses, supporting climate regulation, coastal protection, fisheries and other ecosystem services. Rapid global change, including ocean warming and marine heatwaves, acidification, deoxygenation, eutrophication, pollution and overuse reshape microbial communities and their functions across marine habitats. These changes can alter carbon, nitrogen and sulfur cycles, promote microbialization and harmful algal blooms, disrupt host–microbiome associations and modify pathogen and antimicrobial resistance dynamics, collectively amplifying the ecological and societal impacts of global change. This Review frames marine microbiomes as cross-scale mediators that translate external pressures, including climate change, pollution, eutrophication and habitat degradation, into altered microbial metabolism, biogeochemical fluxes, host-associated health outcomes, ecosystem service consequences and broader One Health risks. We synthesize shared mechanisms and cross-habitat patterns, highlight cases in which microbiome interventions and stewardship could mitigate impacts and/or accelerate recovery, and outline management options ranging from the reduction of local stressors to emerging microbiome stewardship approaches in ecosystem restoration. Building upon this, we outline pathways for embedding marine microbiome science into globally coordinated One Health strategies, operational management protocols and financing frameworks that align economic incentives with long-term ecosystem and public health outcomes. Global change is transforming marine microbial communities. In this Review, Peixoto and colleagues explore the effects of climate and anthropogenic stressors on microbiome composition and function across marine environments, assess their consequences for ecosystem functioning, and propose management and mitigation strategies to improve ocean health through a One Health perspective.
Prebiotics and fermentable fibre modulate gut microbiota composition and function in ways considered beneficial to health. However, both microbiota and clinical responses can vary widely among individuals, which reduces their efficacy as dietary interventions across populations and thus represents a key challenge for the field. In this Review, we discuss potential reasons for the individualized responses to prebiotics and putative prebiotic fibres and how this variability influences interactions among gut microbial species as well as between microorganisms and fibre structures. We further describe strategies for predicting and optimizing responses to prebiotic and putative prebiotic fibre treatments. Specifically, we highlight methods for targeted and predictable individual responses using systems biology, mechanistic modelling and machine learning approaches. We also consider how the physicochemical structures of fermentable fibre influence similarity in gut microbial responses. By integrating this knowledge, solutions are proposed to overcome inter-individual variability and improve the clinical efficacy and utility of prebiotic fibres. Prebiotics and dietary fibre show highly individualized effects on gut microbiota and clinical outcomes, challenging their consistent effectiveness across populations. This Review examines the drivers of this variability, presents predictive approaches and discusses strategies to optimize prebiotic responses across individuals.
This study provides evidence that afforestation and reforestation can increase soil carbon storage and support soil microbial communities, thus highlighting their potential in nature-based climate solutions.
