Unexpected vulnerability of to polymyxin B under anaerobic condition.

Gram-positive exhibited higher susceptibility (>4-fold) to polymyxin B (PMB), the canonical antimicrobial peptide against Gram-negative bacteria, under anaerobic condition than aerobic condition. Anaerobically grown exhibited high vulnerability to PMB, leading to alteration of cell surface and morphology, as observed based on their high dansyl-PMB affinity (>2.9-fold), a proportion (>8.

Contractile injection systems facilitate sporogenic differentiation of Streptomyces davawensis through the action of a phage tapemeasure protein-related effector.

Contractile injection systems (CISs) are prokaryotic phage tail-like nanostructures loading effector proteins that mediate various biological processes. Although CIS functions have been diversified through evolution and hold the great potential as protein delivery systems, the functional characterisation of CISs and their effectors is currently limited to a few CIS lineages. Here, we show that the CISs of Streptomyces davawensis belong to a unique group of bacterial CISs distributed across distant phyla and facilitate sporogenic differentiation of this bacterium.

Mucosal adjuvanticity and mucosal booster effect of colibactin-depleted probiotic membrane vesicles.

There is a growing interest in development of novel vaccines against respiratory tract infections, due to COVID-19 pandemic. Here, we examined mucosal adjuvanticity and the mucosal booster effect of membrane vesicles (MVs) of a novel probiotic derivative lacking both flagella and potentially carcinogenic colibactin (ΔΔ). ΔΔ-derived MVs showed rather strong mucosal adjuvanticity as compared to those of a single flagellar mutant strain (Δ-MVs).

Biological and Chemical Approaches for Controlling Harmful Microcystis Blooms.

The proliferation of harmful cyanobacterial blooms dominated by Microcystis aeruginosa has become an increasingly serious problem in freshwater ecosystems due to climate change and eutrophication. Microcystis-blooms in freshwater generate compounds with unpleasant odors, reduce the levels of dissolved O, and excrete microcystins into aquatic ecosystems, potentially harming various organisms, including humans. Various chemical and biological approaches have thus been developed to mitigate the impact of the blooms, though issues such as secondary pollution and high economic costs have not been adequately addressed.

Colony-Based Electrochemistry Reveals Electron Conduction Mechanisms Mediated by Cytochromes and Flavins in .

Bacteria utilize electron conduction in their communities to drive their metabolism, which has led to the development of various environmental technologies, such as electrochemical microbial systems and anaerobic digestion. It is challenging to measure the conductivity among bacterial cells when they hardly form stable biofilms on electrodes. This makes it difficult to identify the biomolecules involved in electron conduction.

Genotoxic stress stimulates eDNA release via explosive cell lysis and thereby promotes streamer formation of Burkholderia cenocepacia H111 cultured in a microfluidic device.

DNA is a component of biofilms, but the triggers of DNA release during biofilm formation and how DNA contributes to biofilm development are poorly investigated. One key mechanism involved in DNA release is explosive cell lysis, which is a consequence of prophage induction. In this article, the role of explosive cell lysis in biofilm formation was investigated in the opportunistic human pathogen Burkholderia cenocepacia H111 (H111).

The role of peptidoglycan hydrolases in the formation and toxicity of membrane vesicles.

Bacterial membrane vesicles (MVs) have been reported to kill other bacteria. In the case of the bactericidal activity has been attributed to an unidentified 26 kDa peptidoglycan (PG) hydrolase that is associated with MVs and gives rise to a lytic band on zymograms using murein sacculi as substrate. In this study, we employed a proteomics approach to show that this PG hydrolase is the AmphD3 amidase.

Iron Delivery through Membrane Vesicles in Corynebacterium glutamicum.

Bacterial cells form and release membrane vesicles (MVs) originating from cellular membranes. In recent years, many biological functions of bacterial MVs have been identified. Here, we show that MVs derived from Corynebacterium glutamicum, a model organism for mycolic acid-containing bacteria, can mediate iron acquisition and other phylogenetically related bacteria.

Intracellular Phage Tail-Like Nanostructures Affect Susceptibility of Streptomyces lividans to Osmotic Stress.

Contractile injection systems (CISs) are a large group of phage tail-like nanostructures conserved among bacteria. Despite their wide distribution, the biological significance of CISs in bacteria remains largely unclear except for a few unicellular bacteria. Here, we show that Streptomyces lividans-a model organism of filamentous Gram-positive bacteria with highly conserved CIS-related gene clusters-produces intracellular CIS-like nanostructures ( phage tail-like particles [SLPs]) that affect phenotypes of this bacterium under hyperosmotic conditions.

Composition and functions of bacterial membrane vesicles.

Extracellular vesicles are produced by species across all domains of life, suggesting that vesiculation represents a fundamental principle of living matter. In Gram-negative bacteria, membrane vesicles (MVs) can originate either from blebs of the outer membrane or from endolysin-triggered explosive cell lysis, which is often induced by genotoxic stress. Although less is known about the mechanisms of vesiculation in Gram-positive and Gram-neutral bacteria, recent research has shown that both lysis and blebbing mechanisms also exist in these organisms.

A Single Shot of Vesicles.

Bacteria communicate through signaling molecules that coordinate group behavior. Hydrophobic signals that do not diffuse in aqueous environments are used as signaling molecules by several bacteria. However, limited information is currently available on the mechanisms by which these molecules are transported between cells.

Physical Properties and Shifting of the Extracellular Membrane Vesicles Attached to Living Bacterial Cell Surfaces.

Bacterial cells release nanometer-sized extracellular membrane vesicles (MVs) to deliver cargo molecules for use in mediating various biological processes. However, the detailed processes of transporting these cargos from MVs to recipient cells remain unclear because of the lack of imaging techniques to image nanometer-sized fragile vesicles in a living bacterial cell surface. Herein, we quantitatively demonstrated that the direct binding of MV to the cell surface significantly promotes hydrophobic quorum-sensing signal (C16-HSL) transportation to the recipient cells.

Physiological Benefits of Oxygen-Terminating Extracellular Electron Transfer.

Extracellular electron transfer (EET) is a process via which certain microorganisms, such as bacteria, exchange electrons with extracellular materials by creating an electrical link across their membranes. EET has been studied for the reactions on solid materials such as minerals and electrodes with implication in geobiology and biotechnology. EET-capable bacteria exhibit broad phylogenetic diversity, and some are found in environments with various types of electron acceptors/donors not limited to electrodes or minerals.

Nanostructure Control of an Antibiotic-Based Polyion Complex Using a Series of Polycations with Different Side-Chain Modification Rates.

Developing nanovehicles for delivering antibiotics is a promising approach to overcome the issue of antibiotic resistance. This study aims to utilize a polyion complex (PICs) system for developing novel nanovehicles for polymyxin-type antibiotics, which are known as last resort drugs. The formation of antibiotic-based PIC nanostructures is investigated using colistimethate sodium (CMS), an anionic cyclic short peptide, and a series of block catiomers bearing different amounts of guanidinium moieties on their side chains.

Controllable secretion of multilayer vesicles driven by microbial polymer accumulation.

Membrane vesicles (MVs) are formed in various microorganisms triggered by physiological and environmental phenomena. In this study, we have discovered that the biogenesis of MV took place in the recombinant cell of Escherichia coli BW25113 strain that intracellularly accumulates microbial polyester, polyhydroxybutyrate (PHB). This discovery was achieved as a trigger of foam formation during the microbial PHB fermentation.

Phage Genes Induce Quorum Sensing Signal Release through Membrane Vesicle Formation.

Membrane vesicles (MVs) released from the bacterium Paracoccus denitrificans Pd1222 are enriched with the quorum sensing (QS) signaling molecule N-hexadecanoyl-l-homoserine lactone (C16-HSL). However, the biogenesis of MVs in Pd1222 remains unclear. Investigations on MV formation are crucial for obtaining a more detailed understanding of the dynamics of MV-assisted signaling.

Nitric-oxide-driven oxygen release in anoxic .

Denitrification supports anoxic growth of in infections. Moreover, denitrification may provide oxygen (O) resulting from dismutation of the denitrification intermediate nitric oxide (NO) as seen in . To examine the prevalence of NO dismutation we studied O release by in airtight vials.

Ratio of Electron Donor to Acceptor Influences Metabolic Specialization and Denitrification Dynamics in in a Mixed Carbon Medium.

Denitrifying microbes sequentially reduce nitrate (NO ) to nitrite (NO ), NO, NO, and N through enzymes encoded by , , , and . Some denitrifiers maintain the whole four-gene pathway, but others possess partial pathways. Partial denitrifiers may evolve through metabolic specialization whereas complete denitrifiers may adapt toward greater metabolic flexibility in nitrogen oxide (NO ) utilization.

Biogenesis of Outer Membrane Vesicles Concentrates the Unsaturated Fatty Acid of Phosphatidylinositol in .

Bacterial outer membrane vesicles (OMVs) are spherical lipid bilayer nanostructures released by bacteria that facilitate oral biofilm formation cellular aggregation and intercellular communication. Recent studies have revealed that is one of the dominant members of oral biofilms; however, their potential for OMV production has yet to be investigated. This study demonstrated the biogenesis of OMVs in associated with the concentration of unsaturated fatty acids of phosphatidylinositol (PI) and characterized the size and protein profile of OMVs produced at growth phases.

Autolysis-mediated membrane vesicle formation in Bacillus subtilis.

It is known that Bacillus subtilis releases membrane vesicles (MVs) during the SOS response, which is associated with cell lysis triggered by the PBSX prophage-encoded cell-lytic enzymes XhlAB and XlyA. In this study, we demonstrate that MVs are released under various stress conditions: sucrose fatty acid ester (SFE; surfactant) treatment, cold shock, starvation, and oxygen deficiency. B.

Mycolic acid-containing bacteria trigger distinct types of membrane vesicles through different routes.

Bacterial membrane vesicles (MVs) are attracting considerable attention in diverse fields of life science and biotechnology due to their potential for various applications. Although there has been progress in determining the mechanisms of MV formation in Gram-negative and Gram-positive bacteria, the mechanisms in mycolic acid-containing bacteria remain an unsolved question due to its complex cell envelope structure. Here, by adapting super-resolution live-cell imaging and biochemical analysis, we show that form distinct types of MVs via different routes in response to environmental conditions.

Roadmap on emerging concepts in the physical biology of bacterial biofilms: from surface sensing to community formation.

Bacterial biofilms are communities of bacteria that exist as aggregates that can adhere to surfaces or be free-standing. This complex, social mode of cellular organization is fundamental to the physiology of microbes and often exhibits surprising behavior. Bacterial biofilms are more than the sum of their parts: single-cell behavior has a complex relation to collective community behavior, in a manner perhaps cognate to the complex relation between atomic physics and condensed matter physics.