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Microbial Physiology 2021Predatory bacteria gained interest in the last 20 years. Nevertheless, only a few species are well characterized. The endobiotic predator Bdellovibrio bacteriovorus... (Review)
Review
Predatory bacteria gained interest in the last 20 years. Nevertheless, only a few species are well characterized. The endobiotic predator Bdellovibrio bacteriovorus invades its prey to consume it from the inside, whereas Myxococcus xanthus hunts as a whole group to overcome its prey. Both species were described to prey on cyanobacteria as well. This minireview summarizes the findings of the last 20 years of predatory bacteria of cyanobacteria and is supplemented by new findings from a screening experiment for bacterial predators of the model organism Anabaena variabilis PCC 7937. Known predatory bacteria of cyanobacteria belong to the phyla Proteobacteria, Bacteroidetes, and Firmicutes and follow different hunting strategies. The underlying mechanisms are in most cases not known in much detail. Isolates from the screening experiment were clustered after predation behaviour and analyzed with respect to their size. The effect of predation in high nitrate levels and the occurrence of nitrogen-fixing cells, called heterocysts, are addressed.
Topics: Animals; Bdellovibrio bacteriovorus; Cyanobacteria; Myxococcus xanthus; Predatory Behavior
PubMed: 34010833
DOI: 10.1159/000516427 -
Current Opinion in Cell Biology Jun 2022Bacterial cells are spatiotemporally highly organised with proteins localising dynamically to distinct subcellular regions. Motility in the rod-shaped Myxococcus xanthus... (Review)
Review
Bacterial cells are spatiotemporally highly organised with proteins localising dynamically to distinct subcellular regions. Motility in the rod-shaped Myxococcus xanthus cells represents an example of signal-induced spatiotemporal regulation of cell polarity. M. xanthus cells move across surfaces with defined front-rear polarity; occasionally, they invert polarity and, in parallel, reverse direction of movement. The polarity module establishes front-rear polarity between reversals and consists of the Ras-like GTPase MglA and its cognate GEF and GAP, that all localise asymmetrically to the cell poles. The Frz chemosensory system constitutes the polarity inversion module and interfaces with the proteins of the polarity module, thereby triggering their polar repositioning. As a result, the polarity proteins, over time, toggle between the cell poles causing cells to oscillate irregularly. Here, we review recent progress in how front-rear polarity is established by the polarity module and inverted by the Frz system and highlight open questions for future studies.
Topics: Bacterial Proteins; Cell Polarity; GTP Phosphohydrolases; Myxococcus xanthus
PubMed: 35367928
DOI: 10.1016/j.ceb.2022.102076 -
Frontiers in Chemistry 2022Natural products derived from microorganisms play a prominent role in drug discovery as potential anti-infective agents. Over the past few decades, lipopeptides produced... (Review)
Review
Natural products derived from microorganisms play a prominent role in drug discovery as potential anti-infective agents. Over the past few decades, lipopeptides produced by particularly , , , and cyanobacteria species, have been extensively studied for their antimicrobial potential. Subsequently, daptomycin and polymyxin B were approved by the Food and Drug Administration as lipopeptide antibiotics. Recent studies have however, indicated that , and , as well as predatory bacteria such as , and , hold promise as relatively underexplored sources of novel classes of lipopeptides. This review will thus highlight the structures and the newly discovered scaffolds of lipopeptide families produced by these bacterial genera, with potential antimicrobial activities. Additionally, insight into the mode of action and biosynthesis of these lipopeptides will be provided and the application of a genome mining approach, to ascertain the biosynthetic gene cluster potential of these bacterial genera (genomes available on the National Center for Biotechnology Information) for their future pharmaceutical exploitation, will be discussed.
PubMed: 36277345
DOI: 10.3389/fchem.2022.1025979 -
Frontiers in Microbiology 2020Myxobacteria are ubiquitous in soil environments. They display a complex life cycle: vegetatively growing cells coordinate their motility to form multicellular swarms,... (Review)
Review
Myxobacteria are ubiquitous in soil environments. They display a complex life cycle: vegetatively growing cells coordinate their motility to form multicellular swarms, which upon starvation aggregate into large fruiting bodies where cells differentiate into spores. In addition to growing as saprophytes, Myxobacteria are predators that actively kill bacteria of other species to consume their biomass. In this review, we summarize research on the predation behavior of the model myxobacterium which can access nutrients from a broad spectrum of microorganisms. displays an epibiotic predation strategy, i.e., it induces prey lysis from the outside and feeds on the released biomass. This predatory behavior encompasses various processes: Gliding motility and induced cell reversals allow to encounter prey and to remain within the area to sweep up its biomass, which causes the characteristic "rippling" of preying populations. Antibiotics and secreted bacteriolytic enzymes appear to be important predation factors, which are possibly targeted to prey cells with the aid of outer membrane vesicles. However, certain bacteria protect themselves from predation by forming mechanical barriers, such as biofilms and mucoid colonies, or by secreting antibiotics. Further understanding the molecular mechanisms that mediate myxobacterial predation will offer fascinating insight into the reciprocal relationships of bacteria in complex communities, and might spur application-oriented research on the development of novel antibacterial strategies.
PubMed: 32010119
DOI: 10.3389/fmicb.2020.00002 -
Scientific Reports Mar 2021Encapsulins are recently discovered protein compartments able to specifically encapsulate cargo proteins in vivo. Encapsulation is dependent on C-terminal targeting...
Encapsulins are recently discovered protein compartments able to specifically encapsulate cargo proteins in vivo. Encapsulation is dependent on C-terminal targeting peptides (TPs). Here, we characterize and engineer TP-shell interactions in the Thermotoga maritima and Myxococcus xanthus encapsulin systems. Using force-field modeling and particle fluorescence measurements we show that TPs vary in native specificity and binding strength, and that TP-shell interactions are determined by hydrophobic and ionic interactions as well as TP flexibility. We design a set of TPs with a variety of predicted binding strengths and experimentally characterize these designs. This yields a set of TPs with novel binding characteristics representing a potentially useful toolbox for future nanoreactor engineering aimed at controlling cargo loading efficiency and the relative stoichiometry of multiple concurrently loaded cargo proteins.
Topics: Bacterial Proteins; Models, Molecular; Myxococcus xanthus; Nanostructures; Peptides; Thermotoga maritima
PubMed: 33654191
DOI: 10.1038/s41598-021-84329-z -
Current Opinion in Microbiology Apr 2024Bacteria utilize type IV pili (T4P) to interact with their environment, where they facilitate processes including motility, adherence, and DNA uptake. T4P require... (Review)
Review
Bacteria utilize type IV pili (T4P) to interact with their environment, where they facilitate processes including motility, adherence, and DNA uptake. T4P require multisubunit, membrane-spanning nanomachines for assembly. The tight adherence (Tad) pili are an Archaea-derived T4P subgroup whose machinery exhibits significant mechanistic and architectural differences from bacterial type IVa and IVb pili. Most Tad biosynthetic genes are encoded in a single locus that is widespread in bacteria due to facile acquisition via horizontal gene transfer. These loci experience extensive structural rearrangements, including the acquisition of novel regulatory or biosynthetic genes, which fine-tune their function. This has permitted their integration into many different bacterial lifestyles, including the Caulobacter crescentus cell cycle, Myxococcus xanthus predation, and numerous plant and mammalian pathogens and symbionts.
PubMed: 38579360
DOI: 10.1016/j.mib.2024.102468 -
Frontiers in Microbiology 2024Bacterial predators are widely distributed across a variety of natural environments. Understanding predatory interactions is of great importance since they play a... (Review)
Review
Bacterial predators are widely distributed across a variety of natural environments. Understanding predatory interactions is of great importance since they play a defining role in shaping microbial communities in habitats such as soils. is a soil-dwelling bacterial predator that can prey on Gram-positive and Gram-negative bacteria and even on eukaryotic microorganisms. This model organism has been studied for many decades for its unusual lifecycle, characterized by the formation of multicellular fruiting bodies filled with myxospores. However, less is known about its predatory behavior despite being an integral part of its lifecycle. Predation in is a multifactorial process that involves several mechanisms working synergistically, including motility systems to efficiently track and hunt prey, and a combination of short-range and contact-dependent mechanisms to achieve prey death and feed on them. In the short-range attack, is best known for the collective production of secondary metabolites and hydrolytic enzymes to kill prey and degrade cellular components. On the other hand, contact-dependent killing is a cell-to-cell process that relies on Tad-like and type III secretion systems. Furthermore, recent research has revealed that metals also play an important role during predation, either by inducing oxidative stress in the prey, or by competing for essential metals. In this paper, we review the current knowledge about predation, focusing on the different mechanisms used to hunt, kill, and feed on its prey, considering the most recent discoveries and the transcriptomic data available.
PubMed: 38328431
DOI: 10.3389/fmicb.2024.1339696 -
Microorganisms Jun 2023Predatory bacteria, along with the biology of their predatory behavior, have attracted interest in terms of their ecological significance and industrial applications, a... (Review)
Review
Predatory bacteria, along with the biology of their predatory behavior, have attracted interest in terms of their ecological significance and industrial applications, a trend that has been even more pronounced since the comprehensive review in 2016. This mini-review does not cover research trends, such as the role of outer membrane vesicles in myxobacterial predation, but provides an overview of the classification and newly described taxa of predatory bacteria since 2016, particularly with regard to phylogenetic aspects. Among them, it is noteworthy that in 2020 there was a major phylogenetic reorganization that the taxa hosting and , formerly classified as , were proposed as the new phyla and , respectively. Predatory bacteria have been reported from other phyla, especially from the candidate divisions. Predatory bacteria that prey on cyanobacteria and predatory cyanobacteria that prey on have also been found. These are also covered in this mini-review, and trans-phylum phylogenetic trees are presented.
PubMed: 37512846
DOI: 10.3390/microorganisms11071673 -
Microbiology (Reading, England) Jul 2023Myxobacteria are social microbial predators that use cell-cell contacts to identify bacterial or fungal prey and to differentiate kin relatives to initiate cellular... (Review)
Review
Myxobacteria are social microbial predators that use cell-cell contacts to identify bacterial or fungal prey and to differentiate kin relatives to initiate cellular responses. For prey killing, they assemble Tad-like and type III-like secretion systems at contact sites. For kin discrimination (KD), they assemble outer membrane exchange complexes composed of the TraA and TraB receptors at contacts sites. A type VI secretion system and Rhs proteins also mediate KD. Following cellular recognition, these systems deliver appropriate effectors into target cells. For prey, this leads to cell death and lysis for nutrient consumption by myxobacteria. In KD, a panel of effectors are delivered, and if adjacent cells are clonal cells, resistance ensues because they express a cognate panel of immunity factors; while nonkin lack complete immunity and are intoxicated. This review compares and contrasts recent findings from these systems in myxobacteria.
Topics: Animals; Myxococcales; Predatory Behavior; Myxococcus xanthus; Bacterial Proteins
PubMed: 37494115
DOI: 10.1099/mic.0.001372 -
Nature Communications Sep 2023Many species, such as fish schools or bird flocks, rely on collective motion to forage, prey, or escape predators. Likewise, Myxococcus xanthus forages and moves...
Many species, such as fish schools or bird flocks, rely on collective motion to forage, prey, or escape predators. Likewise, Myxococcus xanthus forages and moves collectively to prey and feed on other bacterial species. These activities require two distinct motility machines enabling adventurous (A) and social (S) gliding, however when and how these mechanisms are used has remained elusive. Here, we address this long-standing question by applying multiscale semantic cell tracking during predation. We show that: (1) foragers and swarms can comprise A- and S-motile cells, with single cells exchanging frequently between these groups; (2) A-motility is critical to ensure the directional movement of both foragers and swarms; (3) the combined action of A- and S-motile cells within swarms leads to increased predation efficiencies. These results challenge the notion that A- and S-motilities are exclusive to foragers and swarms, and show that these machines act synergistically to enhance predation efficiency.
Topics: Animals; Predatory Behavior; Cell Tracking; Cooperative Behavior; Motion; Myxococcus xanthus
PubMed: 37696789
DOI: 10.1038/s41467-023-41193-x