scholarly journals A Tad-like apparatus is required for contact-dependent prey killing in predatory social bacteria

2021 ◽  
Author(s):  
Sofiene Seef ◽  
Julien Herrou ◽  
Paul de Boissier ◽  
Laetitia My ◽  
Gael Brasseur ◽  
...  
Keyword(s):  
Cell Interaction ◽  
Prey Cell ◽  
Predator Prey ◽  
New Class ◽  
Tight Contact ◽  
Type Iv ◽  
Secreted Factors ◽  
Predatory Bacteria ◽  
Prey Killing ◽  
Dependent Mechanism

SummaryMyxococcus xanthus, a soil bacterium, predates collectively using motility to invade prey colonies. Prey lysis is mostly thought to rely on secreted factors, cocktails of antibiotics and enzymes, and perhaps a mysterious contact-dependent mechanism. In this study we show that the coupling of A-motility and contact-dependent killing is the central predatory mechanism driving effective prey colony invasion and consumption. At the molecular level, contact-dependent killing is driven by a newly discovered type IV filament-like machinery (Kil) that both promotes motility arrest and prey cell plasmolysis. In this process, Kil proteins assemble at the predator-prey contact site, suggesting that they allow tight contact with prey cells for their intoxication. Kil-like systems form a new class of Tad-like machineries in predatory bacteria, suggesting a conserved function in predator-prey interactions. This study further reveals a novel cell-cell interaction function for bacterial pili-like assemblages.

scholarly journals A Tad-like apparatus is required for contact-dependent prey killing in predatory social bacteria

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Sofiene Seef ◽  
Julien Herrou ◽  
Paul de Boissier ◽  
Laetitia My ◽  
Gael Brasseur ◽  
...  
Keyword(s):  
Molecular Level ◽  
Cell Interaction ◽  
Prey Cell ◽  
Predator Prey ◽  
New Class ◽  
Tight Contact ◽  
Type Iv ◽  
Secreted Factors ◽  
Predatory Bacteria ◽  
Prey Killing

Myxococcus xanthus, a soil bacterium, predates collectively using motility to invade prey colonies. Prey lysis is mostly thought to rely on secreted factors, cocktails of antibiotics and enzymes, and direct contac with Myxococcus cells. In this study, we show that on surfaces the coupling of A-motility and contact-dependent killing is the central predatory mechanism driving effective prey colony invasion and consumption. At the molecular level, contact-dependent killing involves a newly discovered type IV filament-like machinery (Kil) that both promotes motility arrest and prey cell plasmolysis. In this process, Kil proteins assemble at the predator-prey contact site, suggesting that they allow tight contact with prey cells for their intoxication. Kil-like systems form a new class of Tad-like machineries in predatory bacteria, suggesting a conserved function in predator-prey interactions. This study further reveals a novel cell-cell interaction function for bacterial pili-like assemblages.

Predation by Bdellovibrio bacteriovorus transforms the landscape and community assembly of bacterial biofilms

2020 ◽  
Author(s):  
Benjamin R. Wucher ◽  
Mennat Elsayed ◽  
Daniel E. Kadouri ◽  
Carey D. Nadell
Keyword(s):  
Community Assembly ◽  
Natural Environments ◽  
Prey Cell ◽  
Bdellovibrio Bacteriovorus ◽  
Biofilm Growth ◽  
Protection Mechanism ◽  
Predator Prey ◽  
Predatory Bacteria ◽  
Prey Interaction ◽  
Micrometer Scale

The predatory bacterium Bdellovibrio bacteriovorus follows a life cycle in which it attaches to the exterior of a Gram-negative prey cell, enters the periplasm, and harvests resources to replicate before lysing the host to find new prey. Predatory bacteria such as this are common in many natural environments, as are groups of matrix-bound clusters of prey cells, termed biofilms. Despite the ubiquity of both predatory bacteria and biofilm-dwelling prey, the interaction between B. bacteriovorus and prey cells inside biofilms has received little attention and has not yet been studied at the micrometer scale. Filling this knowledge is critical to understanding the nature of predator-prey interaction in nature. Here we show that B. bacteriovorus is able to prey upon biofilms of the pathogen Vibrio cholerae, but only up until a critical maturation threshold past which the prey biofilms are protected from their predators. We determine the contribution of matrix secretion and cell-cell packing of the prey biofilm toward this protection mechanism. Our results demonstrate that B. bacteriovorus predation in the context of this protection threshold fundamentally transforms the sub-millimeter scale landscape of biofilm growth, as well as the process of community assembly as new potential biofilm residents enter the system.

scholarly journals Investigation on dynamics of an impulsive predator–prey system with generalized Holling type IV functional response and anti-predator behavior

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Sekson Sirisubtawee ◽  
Nattawut Khansai ◽  
Akapak Charoenloedmongkhon
Keyword(s):  
Periodic Solution ◽  
Functional Response ◽  
Impulsive Control ◽  
Positive Periodic Solution ◽  
Existence Condition ◽  
Predator Prey ◽  
Type Iv ◽  
Prey System ◽  
Existence And Stability ◽  
Predator Behavior

AbstractIn the present article, we propose and analyze a new mathematical model for a predator–prey system including the following terms: a Monod–Haldane functional response (a generalized Holling type IV), a term describing the anti-predator behavior of prey populations and one for an impulsive control strategy. In particular, we establish the existence condition under which the system has a locally asymptotically stable prey-eradication periodic solution. Violating such a condition, the system turns out to be permanent. Employing bifurcation theory, some conditions, under which the existence and stability of a positive periodic solution of the system occur but its prey-eradication periodic solution becomes unstable, are provided. Furthermore, numerical simulations for the proposed model are given to confirm the obtained theoretical results.

scholarly journals Shadowing the Actions of a Predator: Backlit Fluorescent Microscopy Reveals Synchronous Nonbinary Septation of Predatory Bdellovibrio inside Prey and Exit through Discrete Bdelloplast Pores

2010 ◽  
Vol 192 (24) ◽  
pp. 6329-6335 ◽  
Author(s):  
A. K. Fenton ◽  
M. Kanna ◽  
R. D. Woods ◽  
S.-I. Aizawa ◽  
R. E. Sockett
Keyword(s):  
Cell Division ◽  
Outer Membrane ◽  
Fluorescent Microscopy ◽  
Gram Negative Bacteria ◽  
Bacterial Cell Division ◽  
Prey Cell ◽  
Gram Negative ◽  
A Genome ◽  
Predatory Bacteria ◽  
First Time

ABSTRACT The Bdellovibrio are miniature “living antibiotic” predatory bacteria which invade, reseal, and digest other larger Gram-negative bacteria, including pathogens. Nutrients for the replication of Bdellovibrio bacteria come entirely from the digestion of the single invaded bacterium, now called a bdelloplast, which is bound by the original prey outer membrane. Bdellovibrio bacteria are efficient digesters of prey cells, yielding on average 4 to 6 progeny from digestion of a single prey cell of a genome size similar to that of the Bdellovibrio cell itself. The developmental intrabacterial cycle of Bdellovibrio is largely unknown and has never been visualized “live.” Using the latest motorized xy stage with a very defined z-axis control and engineered periplasmically fluorescent prey allows, for the first time, accurate return and visualization without prey bleaching of developing Bdellovibrio cells using solely the inner resources of a prey cell over several hours. We show that Bdellovibrio bacteria do not follow the familiar pattern of bacterial cell division by binary fission. Instead, they septate synchronously to produce both odd and even numbers of progeny, even when two separate Bdellovibrio cells have invaded and develop within a single prey bacterium, producing two different amounts of progeny. Evolution of this novel septation pattern, allowing odd progeny yields, allows optimal use of the finite prey cell resources to produce maximal replicated, predatory bacteria. When replication is complete, Bdellovibrio cells exit the exhausted prey and are seen leaving via discrete pores rather than by breakdown of the entire outer membrane of the prey.

scholarly journals The Dynamic Complexity of a Holling Type-IV Predator-Prey System with Stage Structure and Double Delays

2011 ◽  
Vol 2011 ◽  
pp. 1-19 ◽  
Author(s):  
Yakui Xue ◽  
Xiafeng Duan
Keyword(s):  
Time Delay ◽  
Equilibrium Point ◽  
Dynamical Behavior ◽  
Stage Structure ◽  
Point Of View ◽  
Maturation Time ◽  
Dynamic Complexity ◽  
Predator Prey ◽  
Predator Prey Model ◽  
Type Iv

We invest a predator-prey model of Holling type-IV functional response with stage structure and double delays due to maturation time for both prey and predator. The dynamical behavior of the system is investigated from the point of view of stability switches aspects. We assume that the immature and mature individuals of each species are divided by a fixed age, and the mature predator only attacks the mature prey. Based on some comparison arguments, sharp threshold conditions which are both necessary and sufficient for the global stability of the equilibrium point of predator extinction are obtained. The most important outcome of this paper is that the variation of predator stage structure can affect the existence of the interior equilibrium point and drive the predator into extinction by changing the maturation (through-stage) time delay. Our linear stability work and numerical results show that if the resource is dynamic, as in nature, there is a window in maturation time delay parameters that generate sustainable oscillatory dynamics.

scholarly journals Purification and properties of theEco57lrestriction endonuclease and methylas—prototypes of a new class (type IV)

1992 ◽  
Vol 20 (22) ◽  
pp. 6043-6049 ◽  
Author(s):  
Arvydas Janulaitis ◽  
Maryte Petrusyte ◽  
Zita Maneliene ◽  
Saulius Klimasauskas ◽  
Viktoras Butkus
Keyword(s):  
New Class ◽  
Type Iv ◽  
Purification And Properties

scholarly journals Quantitative Analysis of Lysobacter Predation

2015 ◽  
Vol 81 (20) ◽  
pp. 7098-7105 ◽  
Author(s):  
Ivana Seccareccia ◽  
Christian Kost ◽  
Markus Nett
Keyword(s):  
Experimental Data ◽  
Feeding Strategy ◽  
Predatory Behavior ◽  
Bacterial Group ◽  
Potential Prey ◽  
Bacterial Populations ◽  
Content Type ◽  
Predator Prey ◽  
Prey Killing ◽  
Predatory Potential

ABSTRACTBacteria of the genusLysobacterare considered to be facultative predators that use a feeding strategy similar to that of myxobacteria. Experimental data supporting this assumption, however, are scarce. Therefore, the predatory activities of threeLysobacterspecies were tested in the prey spot plate assay and in the lawn predation assay, which are commonly used to analyze myxobacterial predation. Surprisingly, only one of the testedLysobacterspecies showed predatory behavior in the two assays. This result suggested that not allLysobacterstrains are predatory or, alternatively, that the assays were not appropriate for determining the predatory potential of this bacterial group. To differentiate between the two scenarios, predation was tested in a CFU-based bioassay. For this purpose, defined numbers ofLysobactercells were mixed together with potential prey bacteria featuring phenotypic markers, such as distinctive pigmentation or antibiotic resistance. After 24 h, cocultivated cells were streaked out on agar plates and sizes of bacterial populations were individually determined by counting the respective colonies. Using the CFU-based predation assay, we observed thatLysobacterspp. strongly antagonized other bacteria under nutrient-deficient conditions. Simultaneously, theLysobacterpopulation was increasing, which together with the killing of the cocultured bacteria indicated predation. Variation of the predator/prey ratio revealed that all threeLysobacterspecies tested needed to outnumber their prey for efficient predation, suggesting that they exclusively practiced group predation. In summary, the CFU-based predation assay not only enabled the quantification of prey killing and consumption byLysobacterspp. but also provided insights into their mode of predation.

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