FEMS microbiology reviews最新文献

One hundred years after planctomycetes were discovered and 50 years since the first isolate was successfully cultured, this bacterial phylum remains enigmatic in many ways. In the last few decades, a significant effort to characterize new isolates has resulted in >150 described species, allowing a more comprehensive analysis of their features. However, metagenomic studies reveal that a diverse group of planctomycetes has yet to be cultured and characterized, and that many biological surprises are yet to be revealed. This is the case for the recently discovered phagotrophic Candidatus Uabimicrobium, which challenges our understanding of the distinction between prokaryotes and eukaryotes. The unique biology of planctomycete cells, such as their ability to divide without the FtsZ protein, their complex structure and characteristic morphology, their relatively large genomes containing many genes with unknown function, and their variable metabolic capabilities, imposes significant barriers for researchers. Although ubiquitous, the precise ecological roles of planctomycetes in various environments are still not fully understood. However, their distinctive metabolism opens the door to a large number of potential biotechnological applications, which are beginning to be unveiled. In this article, we first review the historical milestones in planctomycetes research and describe the pioneers of the field. We then describe the controversies and their resolutions, we highlight the past discoveries and current interrogations related to planctomycetes, and discuss the ongoing challenges that hinder a comprehensive understanding of their biology. We end up with directions for exploring the biology and ecological roles of these fascinating organisms.

Bacteria sense and respond to changing environmental conditions using a diverse range of receptors. Currently, the signals recognized by most receptors remain unknown, thereby limiting our understanding of their function. Since its introduction a decade ago, ligand screening by the thermal-shift assay has identified the signal molecules recognized by numerous receptors, solute-binding proteins, and transcriptional regulators. This progress is summarized in this review. Signal identification is facilitated by the fact that ligand-binding domains can be generated as individual soluble proteins that retain the signal-binding capabilities of the full-length proteins. Various issues relevant to the reliability of the thermal shift assay are discussed, including false-positive and false-negative results, the value of a protein pH screen prior to ligand screening, and the need to verify results with methods for the direct study of ligand binding, such as isothermal titration calorimetry. This review was inspired by the XVIII conference on Bacterial Locomotion and Signal Transduction (Cancun, January 2025), where several notable advances were reported based on the application of the thermal shift assay.

Bacteriophages, or phages, depend on their bacterial hosts for proliferation, leading to a coevolutionary relationship characterized by on-going arms races, where bacteria evolve diverse antiphage defense systems. The development of in silico methods and high-throughput screening techniques has dramatically expanded our understanding of bacterial antiphage defense systems, enormously increasing the known repertoire of the distinct mechanisms across various bacterial species. These advances have revealed that bacterial antiphage defense systems exhibit a remarkable level of complexity, ranging from highly conserved to specialized mechanisms, underscoring the intricate nature of bacterial antiphage defense systems. In this review, we provide a concise snapshot of antiphage defense research highlighting two preponderantly commandeered approaches and classification of the known antiphage defense systems. A special focus is placed on the model bacterial pathogen, Pseudomonas aeruginosa in antiphage defense research. We explore the complexity and adaptability of these systems, which play crucial roles in genome evolution and adaptation of P. aeruginosa in response to an arsenal of diverse phage strains, emphasizing the importance of this organism as a key emerging model bacterium in recent antiphage defense research.

Ambrosia gall midges (AGMs) represent an intriguing group within the Cecidomyiidae, one of the most diversified dipteran families. AGMs form galls on plants, where they cultivate and consume fungal symbionts (phytomycetophagy). This mutualistic relationship may play a critical role in larval nutrition, gall morphogenesis, and protection against natural enemies. Although most other fungus-farming taxa have been intensively studied, AGMs have largely been neglected. This review synthesizes current knowledge on the diversity, biology, and ecological interactions of AGM, highlighting the intricate relationships with their fungal symbionts. The implications for adaptive radiation and speciation are critically considered, including how fungal associations may have facilitated ecological flexibility and diversification. We also tackle the processes of coevolution, not only between AGM and their fungal symbionts but also involving plants and parasitoids. We identify the most pressing issues and discrepancies in the current understanding the AGM-fungi interactions. Key areas of future research should include elucidating fungal acquisition and transmission mechanisms, determining the specificity and diversity of AGM-associated fungal communities, understanding the evolutionary pathways leading to phytomycetophagy, and addressing taxonomic challenges within the AGM group, where species identification has been complicated by reliance on gall morphology and host specificity.

Bacterial vaginosis (BV) is a complex polymicrobial vaginal infection that affects a large percentage of women during different stages of life including the reproductive age. In a healthy vaginal environment, the epithelium is colonized by protective Lactobacillus species that make up 90%-95% of the total vaginal microbiota. BV is characterized by a reduction of lactobacilli and a concurrent increase in diverse anaerobic bacteria, including Gardnerella vaginalis, Prevotella bivia, Hoylesella timonensis, and Fannyhessea vaginae. BV is associated with an increased risk of infertility, preterm birth, and a higher susceptibility to sexually transmitted infections (STIs), including Human Immunodeficiency Virus type-1 (HIV-1). This review examines the contribution of individual pathogenic bacteria to the development of BV and the resulting effects on susceptibility to STI. The impact of the different key bacterial virulence factors, such as secreted proteins, biofilm formation, and inflammatory potential on subsequent viral infection are discussed. While antibiotics are commonly prescribed to treat BV, recurrence rates are high, and antimicrobial resistance among BV-associated bacteria is increasingly reported. Understanding the mechanisms underlying BV and the impact of specific bacteria and their virulence factors on viral infections can improve preventive strategies and open up novel therapeutic applications.

Microbial functional ecology is expanding as we can now measure the traits of wild microbes that affect ecosystem functioning. Here, we review techniques and advances that could be the bedrock for a unified framework to study microbial functions. These include our newfound access to environmental microbial genomes, collections of microbial traits, but also our ability to study microbes' distribution and expression. We then explore the technical, ecological, and evolutionary processes that could explain environmental patterns of microbial functional diversity and redundancy. Next, we suggest reconciling microbiology with biodiversity-ecosystem functioning studies by experimentally testing the significance of microbial functional diversity and redundancy for the efficiency, resistance, and resilience of ecosystem processes. Such advances will aid in identifying state shifts and tipping points in microbiomes, enhancing our understanding of how and where will microbes guide Earth's biomes in the context of a changing planet.

Phenotypic heterogeneity in genetically clonal populations facilitates cellular adaptation to adverse environmental conditions while enabling a return to the basal physiological state. It also plays a crucial role in pathogenicity and the acquisition of drug resistance in unicellular organisms and cancer cells, yet the exact contributing factors remain elusive. In this review, we outline the current state of understanding concerning the contribution of phenotypic heterogeneity to fungal pathogenesis and antifungal drug resistance.

The adaptive mechanisms of Burkholderiales during the catabolism of aromatic compounds and abiotic stress are crucial for their fitness and performance. The aims of this report are to review the bacterial adaptation mechanisms to aromatic compounds, oxidative stress, and environmental stressful conditions, focusing on the model aromatic-degrading Paraburkholderia xenovorans LB400, other Burkholderiales, and relevant degrading bacteria. These mechanisms include (i) the stress response during aromatic degradation, (ii) the oxidative stress response to aromatic compounds, (iii) the metabolic adaptation to oxidative stress, (iv) the osmoadaptation to saline stress, (v) the synthesis of siderophore during iron limitation, (vi) the proteostasis network, which plays a crucial role in cellular function maintenance, and (vii) the modification of cellular membranes, morphology, and bacterial lifestyle. Remarkably, we include, for the first time, novel genomic analyses on proteostasis networks, carbon metabolism modulation, and the synthesis of stress-related molecules in P. xenovorans. We analyzed these metabolic features in silico to gain insights into the adaptive strategies of P. xenovorans to challenging environmental conditions. Understanding how to enhance bacterial stress responses can lead to the selection of more robust strains capable of thriving in polluted environments, which is critical for improving biodegradation and bioremediation strategies.

The gut microbiota (GM) is a dynamic ecosystem intricately linked to human health, including metabolic, immune, endocrine, and gastrointestinal functions. Exercise is recognized as a significant modifier of this microbial ecosystem, yet the complexities of this relationship are underexplored. Here, we delve into the multifaceted interactions between structured physical activity and the GM, emphasizing the role of exercise-induced stressors in shaping microbial composition and function. Unique to our review, we discuss the acute effects of different forms of exercise-induced stress on the GM and explore how these responses may influence long-term adaptability, stability, and resilience. Furthermore, we address critical junctures in microbial dynamics leading to shifts between different stable states. Finally, we explore the implications of host-controlled factors such as diet, exercise training, and nutritional supplementation in modulating the microbial community in the gut to optimize athletic performance. We conclude that while the potential to harness the synergistic effects of exercise-induced stressors, dietary interventions, and microbial adaptations appears promising, current evidence remains preliminary, highlighting the need for additional targeted research to guide future strategies that manipulate the GM for optimal health and athletic performance.

The Bacterial Locomotion And Signal Transduction (BLAST) conference was founded in 1991 and has been held biennially thereafter. While BLAST meetings have typically covered two-component and chemotactic signaling, as well as aspects of motor and flagellum, this year's program broadened its scope and included emerging areas of research, such as microbial signal perception, cellular signal processing, downstream physiological impacts of bacterial signaling, microbe interactions and communities, integrative approaches, and technology innovations. This review summarizes the oral presentations from BLAST XVIII, held in January 2025 in Cancun, Mexico.