-
Science (New York, N.Y.) Jan 2022Gasdermin proteins form large membrane pores in human cells that release immune cytokines and induce lytic cell death. Gasdermin pore formation is triggered by...
Gasdermin proteins form large membrane pores in human cells that release immune cytokines and induce lytic cell death. Gasdermin pore formation is triggered by caspase-mediated cleavage during inflammasome signaling and is critical for defense against pathogens and cancer. We discovered gasdermin homologs encoded in bacteria that defended against phages and executed cell death. Structures of bacterial gasdermins revealed a conserved pore-forming domain that was stabilized in the inactive state with a buried lipid modification. Bacterial gasdermins were activated by dedicated caspase-like proteases that catalyzed site-specific cleavage and the removal of an inhibitory C-terminal peptide. Release of autoinhibition induced the assembly of large and heterogeneous pores that disrupted membrane integrity. Thus, pyroptosis is an ancient form of regulated cell death shared between bacteria and animals.
Topics: Apoptosis Regulatory Proteins; Bacteria; Bacterial Proteins; Bacteriophages; Bradyrhizobium; Cell Membrane; Crystallography, X-Ray; Cytophagaceae; Models, Molecular; Myxococcales; Peptide Fragments; Peptide Hydrolases; Protein Conformation; Protein Conformation, alpha-Helical; Protein Domains; Pyroptosis
PubMed: 35025633
DOI: 10.1126/science.abj8432 -
Trends in Microbiology Jun 2021
Topics: Bacterial Proteins; Genome, Bacterial; Metabolome; Movement; Myxococcus xanthus; Secondary Metabolism; Soil Microbiology
PubMed: 33795155
DOI: 10.1016/j.tim.2021.03.006 -
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 -
Research in Microbiology 2023Myxobacteria are Gram-negative eubacteria and they thrive in a variety of habitats including soil rich in organic matter, rotting wood, animal dung and marine... (Review)
Review
Myxobacteria are Gram-negative eubacteria and they thrive in a variety of habitats including soil rich in organic matter, rotting wood, animal dung and marine environment. Myxobacteria are a promising source of new compounds associated with diverse bioactive spectrum and unique mode of action. The genome information of myxobacteria has revealed many orphan biosynthetic pathways indicating that these bacteria can be the source of several novel natural products. In this review, we highlight the biology of myxobacteria with emphasis on their habitat, life cycle, isolation methods and enlist all the bioactive secondary metabolites purified till date and their mode of action.
Topics: Animals; Myxococcales; Bacteria; Biology; Biological Products
PubMed: 37169232
DOI: 10.1016/j.resmic.2023.104079 -
Natural Product Reports Jul 2014Covering: up to the end of 2013. Myxobacteria produce a vast range of structurally diverse natural products with prominent biological activities. Here, we provide a... (Review)
Review
Covering: up to the end of 2013. Myxobacteria produce a vast range of structurally diverse natural products with prominent biological activities. Here, we provide a detailed description and judge the potential of all antibiotically active myxobacterial compounds as lead structures, pointing out their particularities and, if known, their mode of action. Thus, the review provides an overview of the potential of specific compounds, suitable for future investigations and possible clinical applications.
Topics: Animals; Anti-Bacterial Agents; Humans; Mice; Molecular Structure; Myxococcales; Rats
PubMed: 24841474
DOI: 10.1039/c4np00011k -
Current Protein & Peptide Science 2017Cyclic depsipeptides (CDPs) are a family of cyclic peptide-related compounds, of which the ring is mainly composed of amino- and hydroxy acid residues joined by amide... (Review)
Review
Cyclic depsipeptides (CDPs) are a family of cyclic peptide-related compounds, of which the ring is mainly composed of amino- and hydroxy acid residues joined by amide and ester bonds (at least one), leading to a wide diversity of fascinating chemical structures. They differ in both their ring structure and their side chains, especially by the nature of the unusual and non-amino acid building blocks. To date, however, there is no overall uniform chemical classification system available for CDPs and naming of the diverse family members is done rather arbitrarily. Therefore, a broad evaluation of different CDP structures is done, i.e., 1348 naturally occurring CDPs were included, and a straightforward chemical classification system using apparent chemical characteristics is proposed in order to organize the currently scattered CDP data. The overall validity of the classification approach is verified and the compounds categorized in the same groups are considered to be structurally related. This evaluation also revealed that traditionally formed CDP subfamilies, like the dolastatins, might be misleading from a chemical point of view given the structural differences in this subfamily. This up-to-date CDP overview enables peptide and natural product scientists to study the wide diversity in CDP structures, their chemical interrelationships and identification of existing and newly found CDPs. Together with the available information on the species producing these CDPs and their reported biological activities, this paper provides a useful tool to gain new insights into this diverse group of peptides.
Topics: Animals; Biological Products; Cyanobacteria; Data Mining; Databases, Chemical; Databases, Pharmaceutical; Depsipeptides; Humans; Myxococcales; Porifera; Seaweed; Terminology as Topic
PubMed: 28034297
DOI: 10.2174/1389203717666161128141438 -
Journal of Molecular Biology Nov 2015Prokaryotes often reside in groups where a high degree of relatedness has allowed the evolution of cooperative behaviors. However, very few bacteria or archaea have made... (Review)
Review
Prokaryotes often reside in groups where a high degree of relatedness has allowed the evolution of cooperative behaviors. However, very few bacteria or archaea have made the successful transition from unicellular to obligate multicellular life. A notable exception is the myxobacteria, in which cells cooperate to perform group functions highlighted by fruiting body development, an obligate multicellular function. Like all multicellular organisms, myxobacteria face challenges in how to organize and maintain multicellularity. These challenges include maintaining population homeostasis, carrying out tissue repair and regulating the behavior of non-cooperators. Here, we describe the major cooperative behaviors that myxobacteria use: motility, predation and development. In addition, this review emphasizes recent discoveries in the social behavior of outer membrane exchange, wherein kin share outer membrane contents. Finally, we review evidence that outer membrane exchange may be involved in regulating population homeostasis, thus serving as a social tool for myxobacteria to make the cyclic transitions from unicellular to multicellular states.
Topics: Bacterial Outer Membrane Proteins; Myxococcales
PubMed: 26254571
DOI: 10.1016/j.jmb.2015.07.022 -
Molecular Microbiology Jul 2016For many bacteria, motility is essential for survival, growth, virulence, biofilm formation and intra/interspecies interactions. Since natural environments differ,... (Review)
Review
For many bacteria, motility is essential for survival, growth, virulence, biofilm formation and intra/interspecies interactions. Since natural environments differ, bacteria have evolved remarkable motility systems to adapt, including swimming in aqueous media, and swarming, twitching and gliding on solid and semi-solid surfaces. Although tremendous advances have been achieved in understanding swimming and swarming motilities powered by flagella, and twitching motility powered by Type IV pili, little is known about gliding motility. Bacterial gliders are a heterogeneous group containing diverse bacteria that utilize surface motilities that do not depend on traditional flagella or pili, but are powered by mechanisms that are less well understood. Recently, advances in our understanding of the molecular machineries for several gliding bacteria revealed the roles of modified ion channels, secretion systems and unique machinery for surface movements. These novel mechanisms provide rich source materials for studying the function and evolution of complex microbial nanomachines. In this review, we summarize recent findings made on the gliding mechanisms of the myxobacteria, flavobacteria and mycoplasmas.
Topics: Cell Movement; Flavobacteriaceae; Models, Biological; Movement; Mycoplasma; Myxococcales; Secretory Pathway; Virulence
PubMed: 27028358
DOI: 10.1111/mmi.13389 -
Environmental Microbiology Apr 2022Light-induced carotenogenesis in Myxococcus xanthus is controlled by the B -based CarH repressor and photoreceptor, and by a separate intricate pathway involving singlet...
Light-induced carotenogenesis in Myxococcus xanthus is controlled by the B -based CarH repressor and photoreceptor, and by a separate intricate pathway involving singlet oxygen, the B -independent CarH paralogue CarA and various other proteins, some eukaryotic-like. Whether other myxobacteria conserve these pathways and undergo photoregulated carotenogenesis is unknown. Here, comparative analyses across 27 Myxococcales genomes identified carotenogenic genes, albeit arranged differently, with carH often in their genomic vicinity, in all three Myxococcales suborders. However, CarA and its associated factors were found exclusively in suborder Cystobacterineae, with carA-carH invariably in tandem in a syntenic carotenogenic operon, except for Cystobacter/Melittangium, which lack CarA but retain all other factors. We experimentally show B -mediated photoregulated carotenogenesis in representative myxobacteria, and a remarkably plastic CarH operator design and DNA binding across Myxococcales. Unlike the two characterized CarH from other phyla, which are tetrameric, Cystobacter CarH (the first myxobacterial homologue amenable to analysis in vitro) is a dimer that combines direct CarH-like B -based photoregulation with CarA-like DNA binding and inhibition by an antirepressor. This study provides new molecular insights into B -dependent photoreceptors. It further establishes the B -dependent pathway for photoregulated carotenogenesis as broadly prevalent across myxobacteria and its evolution, exclusively in one suborder, into a parallel complex B -independent circuit.
Topics: Bacterial Proteins; DNA; Gene Expression Regulation, Bacterial; Myxococcales; Phosphothreonine; Repressor Proteins
PubMed: 35005822
DOI: 10.1111/1462-2920.15895 -
Viruses Jul 2018Bacteriophages have been used as molecular tools in fundamental biology investigations for decades. Beyond this, however, they play a crucial role in the... (Review)
Review
Bacteriophages have been used as molecular tools in fundamental biology investigations for decades. Beyond this, however, they play a crucial role in the eco-evolutionary dynamics of bacterial communities through their demographic impact and the source of genetic information they represent. The increasing interest in describing ecological and evolutionary aspects of bacteria⁻phage interactions has led to major insights into their fundamental characteristics, including arms race dynamics and acquired bacterial immunity. Here, we review knowledge on the phages of the myxobacteria with a major focus on phages infecting , a bacterial model system widely used to study developmental biology and social evolution. In particular, we focus upon the isolation of myxophages from natural sources and describe the morphology and life cycle parameters, as well as the molecular genetics and genomics of the major groups of myxophages. Finally, we propose several interesting research directions which focus on the interplay between myxobacterial host sociality and bacteria⁻phage interactions.
Topics: Bacteriophages; Evolution, Molecular; Gene Expression Regulation, Bacterial; Genome, Viral; Myxococcus xanthus; Sewage; Soil Microbiology
PubMed: 30021959
DOI: 10.3390/v10070374