Ecological determinants of prevalence of the male-killing bacterium Arsenophonus nasoniae.

Male-killing bacteria are found in a broad range of arthropods. Arsenophonus nasoniae is a male-killing bacterium, causing a 80% reduction of the male progeny in infected Nasonia vitripennis wasps. Although the discovery of A.

The son-killer microbe Arsenophonus nasoniae is a widespread associate of the parasitic wasp Nasonia vitripennis in Europe.

Heritable microbes that exhibit reproductive parasitism are common in insects. One class of these are the male-killing bacteria, which are found in a broad range of insect hosts. Commonly, our knowledge of the incidence of these microbes is based on one or a few sampling sites, and the degree and causes of spatial variation are unclear.

Isolation, culture and characterization of symbionts from two insect species reveal loss of infectious transmission and extended host range.

Vertically transmitted "Heritable" microbial symbionts represent an important component of the biology and ecology of invertebrates. These symbioses evolved originally from ones where infection/acquisition processes occurred within the environment (horizontal transmission). However, the pattern of evolution that follows transition from horizontal to vertical transmission is commonly obscured by the distant relationship between microbes with differing transmission modes.

sp. nov., isolated from the honeybee .

The genus has been traditionally considered to comprise heritable bacterial symbionts of arthropods. Recent work has reported a microbe related to the type species as infecting the honey bee, . The association was unusual for members of the genus in that the microbe-host interaction arose through environmental and social exposure rather than vertical transmission.

, gen. nov., sp. nov., isolated from the leafhopper .

Bacterial endosymbionts are found in multiple arthropod species, where they play crucial roles as nutritional symbionts, defensive symbionts or reproductive parasites. Recent work has highlighted a new clade of heritable microbes within the gammaproteobacteria that enter into both obligate and facultative symbioses, with an obligately required unculturable symbiont recently given the name Symbiopectobacterium. In this study, we describe a culturable rod shaped non-flagellated bacterial symbiont from this clade isolated from the leafhopper .

Erwinia carotovora Quorum Sensing System Regulates Host-Specific Virulence Factors and Development Delay in Drosophila melanogaster.

Multihost bacteria have to rapidly adapt to drastic environmental changes, relying on a fine integration of multiple stimuli for an optimal genetic response. spp. are phytopathogens that cause soft-rot disease.

The Hypercomplex Genome of an Insect Reproductive Parasite Highlights the Importance of Lateral Gene Transfer in Symbiont Biology.

Mobile elements-plasmids and phages-are important components of microbial function and evolution via traits that they encode and their capacity to shuttle genetic material between species. We here report the unusually rich array of mobile elements within the genome of , the son-killer symbiont of the parasitic wasp This microbe's genome has the highest prophage complement reported to date, with over 50 genomic regions that represent either intact or degraded phage material. Moreover, the genome is predicted to include 17 extrachromosomal genetic elements, which carry many genes predicted to be important at the microbe-host interface, derived from a diverse assemblage of insect-associated gammaproteobacteria.

Signal Integration in Quorum Sensing Enables Cross-Species Induction of Virulence in .

Bacterial communities can sense their neighbors, regulating group behaviors in response to cell density and environmental changes. The diversity of signaling networks in a single species has been postulated to allow custom responses to different stimuli; however, little is known about how multiple signals are integrated and the implications of this integration in different ecological contexts. In the plant pathogen (formerly ), two signaling networks-the N-acyl homoserine lactone (AHL) quorum-sensing system and the Gac/Rsm signal transduction pathway-control the expression of secreted plant cell wall-degrading enzymes, its major virulence determinants.

Deinococcus radiodurans can interfere with quorum sensing by producing an AHL-acylase and an AHL-lactonase.

Bacterial communication via the secretion of small diffusible compounds allows microorganisms to regulate gene expression in a coordinated manner. As many virulence traits are regulated in this fashion, disruption of chemical communication has been proposed as novel antimicrobial therapy. Quorum-quenching enzymes have been a promising discovery in this field as they interfere with the communication of Gram-negative bacteria.

Assessing Pseudomonas virulence with nonmammalian host: Galleria mellonella.

Pseudomonas aeruginosa is an opportunistic human pathogen responsible for severe to deadly infections in patients suffering from cystic fibrosis, AIDS, undergoing immune suppressing therapies or suffering from severe burns. In the recent years there has been an increasing interest in exploring animal infection models that, to a certain extent, could mimic human infections. Here we describe the use of the larvae of the greater wax moth Galleria mellonella as a non-expensive, easy-to-use, and easy-to-obtain animal model to study P.

PvdP is a tyrosinase that drives maturation of the pyoverdine chromophore in Pseudomonas aeruginosa.

The iron binding siderophore pyoverdine constitutes a major adaptive factor contributing to both virulence and survival in fluorescent pseudomonads. For decades, pyoverdine production has allowed the identification and classification of fluorescent and nonfluorescent pseudomonads. Here, we demonstrate that PvdP, a periplasmic enzyme of previously unknown function, is a tyrosinase required for the maturation of the pyoverdine chromophore in Pseudomonas aeruginosa.

The multiple signaling systems regulating virulence in Pseudomonas aeruginosa.

Cell-to-cell communication is a major process that allows bacteria to sense and coordinately react to the fluctuating conditions of the surrounding environment. In several pathogens, this process triggers the production of virulence factors and/or a switch in bacterial lifestyle that is a major determining factor in the outcome and severity of the infection. Understanding how bacteria control these signaling systems is crucial to the development of novel antimicrobial agents capable of reducing virulence while allowing the immune system of the host to clear bacterial infection, an approach likely to reduce the selective pressures for development of resistance.

The acylase PvdQ has a conserved function among fluorescent Pseudomonas spp.

Pyoverdine biosynthesis in fluorescent Pseudomonas spp. and especially in the opportunistic human pathogen Pseudomonas aeruginosa has been extensively studied. The acylase PvdQ is required for a maturation step in pyoverdine biosynthesis but also has been proven to be effective in degrading long-chain N-acyl homoserine lactones (AHLs).

The quorum-quenching N-acyl homoserine lactone acylase PvdQ is an Ntn-hydrolase with an unusual substrate-binding pocket.

In many Gram-negative pathogens, their virulent behavior is regulated by quorum sensing, in which diffusible signals such as N-acyl homoserine lactones (AHLs) act as chemical messaging compounds. Enzymatic degradation of these diffusible signals by, e.g.

Role of PvdQ in Pseudomonas aeruginosa virulence under iron-limiting conditions.

PvdQ, an acylase from Pseudomonas aeruginosa PAO1, has been shown to have at least two functions. It can act as a quorum quencher due to its ability to degrade long-chain N-acylhomoserine lactones (AHLs), e.g.

Quorum-quenching acylase reduces the virulence of Pseudomonas aeruginosa in a Caenorhabditis elegans infection model.

The Pseudomonas aeruginosa PAO1 gene pvdQ encodes an acyl-homoserine lactone (AHL) acylase capable of degrading N-(3-oxododecanoyl)-L-homoserine lactone by cleaving the AHL amide. PvdQ has been proven to function as a quorum quencher in vitro in a number of phenotypic assays. To address the question of whether PvdQ also shows quorum-quenching properties in vivo, an infection model based on the nematode Caenorhabditis elegans was explored.

In vitro inhibition of Streptococcus mutans biofilm formation on hydroxyapatite by subinhibitory concentrations of anthraquinones.

We report that certain anthraquinones (AQs) reduce Streptococcus mutans biofilm formation on hydroxyapatite at concentrations below the MIC. Although AQs are known to generate reactive oxygen species, the latter do not underlie the observed effect. Our results suggest that AQs inhibit S.