Current opinion in microbiology最新文献

Myxococcus relies on motility to efficiently invade and predate a prey colony. Upon contact with prey, Myxococcus temporarily halts its motility and initiates prey cell lysis, which involves two contact-dependent predatory machineries, the Kil system and the needleless T3SS*. Predatory cells grow as they invade and feed on prey cells. When dividing, Myxococcus cells systematically pause their movements before division. This highlights a high level of co-ordination between motility and contact-dependent killing but also with cell division. In this review, we give an overview of the different nanomachines used by Myxococcus to move on surfaces, kill by contact, and divide, and we discuss the potential regulatory mechanisms at play during these different processes.

Candida albicans is a ubiquitous fungus of humans. It is not only a component of the oral and intestinal microbiota of most healthy adults but also a major cause of mucosal disorders and life-threatening disseminated infections. Until recently, research on the biology and pathogenesis of the fungus was largely based on a single clinical isolate. We review investigations that have started to dissect a diverse set of C. albicans strains. Using different approaches to leverage the species’ phenotypic and/or genetic diversity, these studies illuminate the wide range of interactions between fungus and host. While connecting genetic variants to phenotypes of interest remains challenging, research on C. albicans’ natural diversity is central to understand fungal commensalism and pathogenesis.

Hybridisation is the crossing of two divergent lineages that give rise to offspring carrying an admixture of both parental genomes. Genome sequencing has revealed that this process is common in the Saccharomycotina, where a growing number of hybrid strains or species, including many pathogenic ones, have been recently described. Hybrids can display unique traits that may drive adaptation to new niches, and some pathogenic hybrids have been shown to have higher prevalence over their parents in human and environmental niches, suggesting a higher fitness and potential to colonise humans. Here, we discuss how hybridisation and its genomic and phenotypic outcomes can shape the evolution of fungal species and may play a role in the emergence of new pathogens.

Animals harbor a diverse array of symbiotic micro-organisms that coexist in communities across different body sites. These microbes maintain host homeostasis and respond to environmental insults to impact host physiological processes. Trillions of indigenous microbes reside in the gastrointestinal tract and engage with the host central nervous system (microbiota–gut–brain axis) by modulating immune responses, interacting with gut intrinsic and extrinsic nervous system, and regulating neuromodulators and biochemicals. These gut microbiota to brain signaling pathways are constantly informed by each other and are hypothesized to mediate brain health across the lifespan. In this review, we will examine the crosstalk of gut microbiota to brain communications in neurological pathologies, with an emphasis on microbial metabolites and neuromodulators, and provide a discussion of recent advances that help elucidate the microbiota as a therapeutic target for treating brain and behavioral disorders.

In this review, we explore the regulation of septal peptidoglycan (sPG) synthesis in bacterial cell division, a critical process for cell viability and proper morphology. Recent single-molecule imaging studies have revealed the processive movement of the FtsW:bPBP synthase complex along the septum, shedding light on the spatiotemporal dynamics of sPG synthases and their regulators. In diderm bacteria (E. coli and C. crescentus), the movement occurs at two distinct speeds, reflecting active synthesis or inactivity driven by FtsZ-treadmilling. In monoderm bacteria (B. subtilis, S. pneumoniae, and S. aureus), however, these enzymes exhibit only the active sPG-track-coupled processive movement. By comparing the dynamics of sPG synthases in these organisms and that of class-A penicillin-binding proteins in vivo and in vitro, we propose a unifying model for septal cell wall synthesis regulation across species, highlighting the roles of the sPG- and Z-tracks in orchestrating a robust bacterial cell wall constriction process.

Carbon dioxide supplies carbon for photosynthetic species and is a major product of respiration for all life forms. Inside the human body where CO₂ is a by-product of the tricarboxylic acid cycle, its level reaches 5% or higher. In the ambient atmosphere, ∼.04% of the air is CO₂. Different organisms can tolerate different CO₂ levels to various degrees, and experiencing higher CO₂ is toxic and can lead to death. The fungal kingdom shows great variations in response to CO₂ that has been documented by different researchers at different time periods. This literature review aims to connect these studies, highlight mechanisms underlying tolerance to high levels of CO₂, and emphasize the effects of CO₂ on fungal metabolism and morphogenesis.

Sulfur is an essential macronutrient for life, and consequently, all living organisms must acquire it from external sources to thrive and grow. Sulfur is a constituent of a multitude of crucial molecules, such as the S-containing proteinogenic amino acids cysteine and methionine; cofactors and prosthetic groups, such as coenzyme-A and iron–sulfur (Fe–S) clusters; and other essential organic molecules, such as glutathione or S-adenosylmethionine. Additionally, sulfur in cysteine thiols is an active redox group that plays paramount roles in protein stability, enzyme catalysis, and redox homeostasis. Furthermore, H₂S is gaining more attention as a crucial signaling molecule that influences metabolism and physiological functions. Given its importance, it is not surprising that sulfur plays key roles in the host–pathogen interaction. However, in contrast to its well-recognized involvement in the plant–pathogen interaction, the specific contributions of sulfur to the human–fungal interaction are much less understood. In this short review, I highlight some of the most important known mechanisms and propose directions for further research.

Natural products (NPs) produced by bacteria, particularly soil actinomycetes, often possess diverse bioactivities and play a crucial role in human health, agriculture, and biotechnology. Soil actinomycete genomes contain a vast number of predicted biosynthetic gene clusters (BGCs) yet to be exploited. Understanding the factors governing NP production in an ecological context and activating cryptic and silent BGCs in soil actinomycetes will provide researchers with a wealth of molecules with potential novel applications. Here, we highlight recent advances in NP discovery strategies employing ecology-inspired approaches and discuss the importance of understanding the environmental signals responsible for activation of NP production, particularly in a soil microbial community context, as well as the challenges that remain.

This review synthesizes recent discoveries of novel archaea clades capable of oxidizing higher alkanes, from volatile ones like ethane to longer-chain alkanes like hexadecane. These archaea, termed anaerobic multicarbon alkane-oxidizing archaea (ANKA), initiate alkane oxidation using alkyl-coenzyme M reductases, enzymes similar to the methyl-coenzyme M reductases of methanogenic and anaerobic methanotrophic archaea (ANME). The polyphyletic alkane-oxidizing archaea group (ALOX), encompassing ANME and ANKA, harbors increasingly complex alkane degradation pathways, correlated with the alkane chain length. We discuss the evolutionary trajectory of these pathways emphasizing metabolic innovations and the acquisition of metabolic modules via lateral gene transfer. Additionally, we explore the mechanisms by which archaea couple alkane oxidation with the reduction of electron acceptors, including electron transfer to partner sulfate-reducing bacteria (SRB). The phylogenetic and functional constraints that shape ALOX–SRB associations are also discussed. We conclude by highlighting the research needs in this emerging research field and its potential applications in biotechnology.

Coronaviruses have exceptionally large RNA genomes and employ multiprotein replication/transcription complexes to orchestrate specific steps of viral RNA genome replication and expression. Most of these processes involve viral cis-acting RNA elements that are engaged in vital RNA–RNA and/or RNA–protein interactions. Over the past years, a large number of studies provided interesting new insight into the structures and, to a lesser extent, functions of specific RNA elements for representative coronaviruses, and there is evidence to suggest that (a majority of) these RNA elements are conserved across genetically divergent coronavirus genera. It is becoming increasingly clear that at least some of these elements do not function in isolation but operate through complex and highly dynamic RNA–RNA interactions. This article reviews structural and functional aspects of cis-acting RNA elements conserved in alpha- and betacoronavirus 5'- and 3'-terminal genome regions, focusing on their critical roles in viral RNA synthesis and gene expression.