Microbiology and Molecular Biology Reviews最新文献

SUMMARYEarly in evolution, cells acquired the ability to use energy to export waste and toxic products against a concentration gradient. In Gram-negative bacteria, the resistance-nodulation-cell division (RND) superfamily of multi-subunit efflux pumps transport toxic molecules to the extracellular milieu. RND efflux pumps require cell-membrane proton motive force to export a wide range of substrates. Within the RND superfamily, Hydrophobe/Amphiphile Efflux 1 (HAE-1) family members have been studied extensively for their critical role in exporting structurally diverse antibiotics and, consequently, their contributions to multidrug resistance. However, HAE-1 RND efflux pumps are also required for pathogen survival in the mammalian host when antibiotics are absent. Here, we investigate the role of HAE-1 RND efflux pumps as virulence determinants. We analyze the genetic evidence that Gram-negative bacterial pathogens require HAE-1 RND efflux pumps to cause infection and briefly discuss the development of therapeutic and prophylactic approaches to interfere with HAE-1 RND efflux pump activity as a complement to existing antibiotics.

SUMMARYCandida species are major yeast pathogens that cause both mucosal candidiasis and life-threatening invasive infections. Most Candida species, including Candida albicans, have long been thought to be "imperfect" due to the lack of a complete sexual reproduction cycle. Since the discovery of the mating type-like locus in C. albicans in 1999, the regulation of (para)sexual reproduction has been intensively investigated in this organism as well as in several phylogenetically closely related species. The (para)sexual cycle is not only critical for the generation of genetic and phenotypic diversity but is also involved in the regulation of other biological processes, such as morphological transitions, biofilm development, and virulence in pathogenic fungi. In this review article, we focus on the unique characteristics and genetic and environmental regulatory mechanisms of parasexual reproduction in the pathogenic Candida species. We discuss the relationship between the white-opaque switching and mating in the Candida species, particularly in C. albicans. We describe recent findings on environmental factors, genetic regulators, and key signaling pathways involved in sexual mating in C. albicans and related species. Finally, we discuss the mating potential and associated regulatory machinery in several Candida species, where parasexual reproduction has not been observed and bring to light some open-ended questions regarding the unique features of parasexual reproduction that should be addressed in future studies in the field.

SUMMARYFungal pathogens cause widespread disease in humans, plants, and animals. Surviving in diverse environments requires fungi to resist attack by a wide range of reactive chemicals, including reactive oxygen species, reactive nitrogen species, and redox-reactive metal ions. Some of these reactive species are from environmental sources or are the byproducts of cellular metabolism. However, in the case of human pathogens, a major threat is attack by the host immune system that employs chemically reactive species. Previous research on chemical attack by the immune system has often focused on hydrogen peroxide as a model oxidant. In this review, we will highlight recent advances in defining how the broad range of chemically reactive species generated by the immune system damage fungal cells, and the mechanisms used by cells to resist this attack. In particular, the pathways used by Candida albicans to protect against chemical attack by the host will be highlighted, as the importance of this common human fungal pathogen has made it a focus of much recent research in this area.

SUMMARYDespite the increasing preventative efforts (vaccines, hygiene, pre-conditioning), respiratory tract (RT) infections pose a significant challenge across mammalian species. Recently, there has been a greater emphasis on promoting healthy microbiome colonization to mitigate respiratory infection in humans and livestock species. In livestock animals, especially in cattle, RT microbiome research has mainly focused on characterizing the respiratory tract microbial community in healthy and sick animals, aiming to identify microbiota linked to disease or health status. However, this approach overlooked the dynamics of RT microbiome that comprises commensal opportunistic pathogens (an element of the pathobiome) contributing to the infection and disease pathogenesis. Moreover, there is a lack of attempts to evaluate the interactions among host immunity-microbiome-pathobiome during pathogenesis for the development of successful microbiome-based interventions to improve cattle respiratory health. Recent research has revealed new insights into the gut-lung axis (GLA) and the regulatory role of the gut microbiota in determining host susceptibility or resilience to respiratory infections. Therefore, this review aims to critically discuss the roles of RT microbiome (including pathobiome) and GLA in respiratory health, while elucidating the mechanisms driving the dynamic transition from a commensal state to pathogenic state during microbiome dysbiosis and immune dysregulation, and identifying microbiome targets for RT health improvement.

SUMMARYBacterial flagella are remarkable rotary machines that enable motility, environmental sensing, and host interaction. In this review, we discuss recent advances in understanding the structure, assembly, and regulation of the flagellum in Salmonella enterica, emphasizing both common principles and distinctive features across bacteria. We discuss the hierarchical gene regulation, the dynamic mechanics of the motor, and recent structural insights into the flagellar core components. We also reflect on the legacy of Howard Berg, whose foundational work in Escherichia coli shaped much of what we know about bacterial locomotion in Gammaproteobacteria. His contributions, from flagellar rotation to chemotaxis and motor dynamics, transformed the field and continue to inspire current research into one of nature's most intricate nanomachines. Finally, we highlight open questions that place bacterial motility within the broader context of cellular processes and call for detailed single-cell observations.

SUMMARYNeurotransmitter signaling pathways play major roles in both molecular and behavioral defenses against pathogen invasion, shaping the ability of Caenorhabditis elegans to sense and respond to environmental challenges. Given the conservation of neurotransmitter signaling pathways, their understanding may not only provide insights into the neurobiology of C. elegans but also has broader implications for our understanding of neural-immune interactions and host defense mechanisms in higher organisms. In this review, we discussed the literature on various neurotransmitter signaling pathways, including serotonergic, dopaminergic/octopaminergic, GABAergic, and glutamatergic pathways, and how these pathways modulate molecular and behavioral immune defense against pathogens.

SUMMARYRNA processing governs RNA function and gene regulation across all domains of life. In Archaea, recent advances in transcriptomics, genetics, and structural biology have uncovered a strikingly complex landscape of RNA processing and regulation. This review provides an up-to-date and comprehensive synthesis of archaeal RNA biology, covering the processing of ribosomal RNA (rRNA), transfer RNA (tRNA), and small noncoding RNAs, including C/D box and H/ACA box sRNAs, SRP RNA, and CRISPR RNAs, as well as emerging insights into mRNA processing and decay. We emphasize the growing knowledge of regulatory sRNAs, including tRNA-derived fragments (tRFs), which introduce new layers of archaeal RNA-based gene control. We also describe the roles of key ribonucleases and RNA chaperones in coordinating RNA processing and post-transcriptional control. These discoveries expand our understanding of how archaea employ RNA-centric strategies to orchestrate gene expression with remarkable specificity and adaptability. By integrating mechanistic insights with evolutionary context, this review provides a new framework for understanding archaeal RNA biology and its relevance to the modular evolution of RNA-based regulation. We also identify major knowledge gaps and propose future research priorities, emphasizing the potential of next-generation approaches to drive the next wave of discovery.

SUMMARYMany mammalian diseases appear to be caused primarily by the abnormal accumulation of self-propagating assemblies of specific host proteins such as Aβ and tau in Alzheimer's disease, α-synuclein (aSyn) in Parkinson's disease, and prion protein (PrP) in classical prion diseases. Most proteinopathies involve a prion-like spreading of the aggregates from localized sites of initiation within the host and, sometimes, between individuals. Often, the pathological assemblies take the form of amyloid fibrils, the cores of many of which have been solved by cryo-electron microscopy, revealing disease-specific, strain-like conformers of the given protein. Amyloids grow via seeded polymerization, a mechanism that is being widely exploited to develop ultrasensitive and specific amplification assays for pathological seeds as biomarkers. Such assays can aid fundamental research, diagnostics, prognostics, and clinical trials for multiple proteinopathies that have been challenging to diagnose and treat. Here, we review the structural biology, transmissibilities, spreading mechanisms, and detection of proteopathic aggregates as well as therapeutic approaches to limiting their accumulation.

SUMMARYAfrica's rich microbial diversity presents a significant opportunity to drive innovation in healthcare, agriculture, and industrial biotechnology through microbial natural product discovery. However, despite its potential, the continent remains underrepresented in the global bioeconomy due to limited microbial culture repositories, inadequate genomic sequencing infrastructure, and weak commercialization models. This review highlights the critical role of microbial biotechnology in advancing Africa's bioeconomy and outlines a roadmap for leveraging indigenous microbial resources. By exploring the Bacterial and Viral Bioinformatics Resource Center (BV-BRC) database, we compiled the genomic distribution of traditional model and emerging non-model bacterial chassis indigenous to Africa. Although the survey is limited to BV-BRC data, this approach provides a reliable snapshot of microbial bioresources suitable for omics-driven biosolution development. The review integrates database insights with literature evidence to identify key microbial genera for further investigation. Key areas include microbial bioprospecting, functional omics, biofortification, and synthetic biology as drivers of sustainable innovation. Challenges such as scaling up biomanufacturing, bridging research-industry gaps, and establishing microbial biofoundries and biobanks are discussed as critical to strengthening Africa's biotechnology landscape. This paper also emphasizes the importance of enabling policy frameworks, strategic funding mechanisms, and public-private partnerships to accelerate commercialization pathways. By investing in microbial biotechnology, Africa can enhance food security, reduce dependency on chemical synthetic inputs, and address pressing issues such as antimicrobial resistance. Strengthening omics research capacity, expanding biomanufacturing infrastructure, and fostering cross-sector collaboration are essential steps toward unlocking Africa's untapped bioeconomic potential and positioning the continent as a global hub for sustainable biosolutions.

SUMMARYEscherichia albertii, initially identified as Hafnia alvei, by the commercial identification biochemical strip, API 20E, was isolated from an infant with diarrhea in Bangladesh in 1989. However, this bacterium was later renamed as a novel species, E. albertii (after M. John Albert, the discoverer) because of its similarities in biochemical and genetic properties to the genus Escherichia, but different from those of any known species in the genus. E. albertii possesses many pathogenic attributes, including a key one, which is the ability to produce attaching and effacing (A/E) lesions in the intestinal mucosa mediated by genes on a 35kb pathogenicity island called the locus of enterocyte effacement. Therefore, it is a member of the family of A/E pathogens. Some of the initially reported enteropathogenic Escherichia coli (EPEC), enterohemorrhagic E. coli (EHEC), Shigella boydii O13, and cytolethal distending toxin II-producing E. coli (CTEC-II) were later confirmed as E. albertii. E. albertii caused sporadic cases of diarrhea and diarrheal outbreaks and rarely extraintestinal infections. E. albertii was also associated with the death of birds in Scotland, UK, and Alaska in the USA. Not only birds (including chickens) but also mammals, including raccoons, seem to be major reservoirs of E. albertii, suggesting that E. albertii is an emerging zoonotic pathogen. Specific detection methods and selective and differential media for E. albertii have been developed for diagnosis. Several E. albertii isolates have been sequenced, revealing key characteristics of the organism. However, there are still many gaps in knowledge that exist regarding this bacterium. In this review, we will describe what is known about some key facets of this bacterium but also directions of future research to fill the knowledge gap.