Analysis of the PixA Inclusion Body Protein of
            <i>Xenorhabdus nematophila</i>

Goetsch, M.; Owen, Heather A.; Goldman, Barry S.; Forst, Steven

doi:10.1128/jb.188.7.2706-2710.2006

Cited by 28 publications

(39 citation statements)

References 21 publications

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“…Other potential candidate signaling molecules could be derived from the insect cadaver. This idea is supported by evidence that nematodes grown in the insect better associate with bacterial symbionts than those reared in vitro on nutrient agar bacterial lawns (29,30). This suggests that metabolites specifically derived from the insect tissues (via either nematode or bacterial metabolism) may be important for symbiont transmission and nutrient adaptation.…”

Section: From the Spent Cadaver To The Ijmentioning

confidence: 91%

“…2D) (28)(29)(30)(31)(32). IJs can persist in the soil for many months (33)(34)(35)(36), and in the IJ receptacle, Xenorhabdus likely expresses traits that support its long-term stationary-phase survival.…”

Section: From the Ij To The Insectmentioning

confidence: 99%

“…Once a few bacterial cells colonize the IJ receptacle, they grow slowly into a population that persists in the host for periods lasting up to months until the nematode enters a new insect host (30,52). The IJ receptacle has some spatial and temporal nutrient complexity that could help trigger adaptive gene expression as IJs age.…”

Section: Persistence In the Ijmentioning

confidence: 99%

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Ready or Not: Microbial Adaptive Responses in Dynamic Symbiosis Environments

Cao

Goodrich‐Blair

2017

J Bacteriol

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In mutually beneficial and pathogenic symbiotic associations, microbes must adapt to the host environment for optimal fitness. Both within an individual host and during transmission between hosts, microbes are exposed to temporal and spatial variation in environmental conditions. The phenomenon of phenotypic variation, in which different subpopulations of cells express distinctive and potentially adaptive characteristics, can contribute to microbial adaptation to a lifestyle that includes rapidly changing environments. The environments experienced by a symbiotic microbe during its life history can be erratic or predictable, and each can impact the evolution of adaptive responses. In particular, the predictability of a rhythmic or cyclical series of environments may promote the evolution of signal transduction cascades that allow preadaptive responses to environments that are likely to be encountered in the future, a phenomenon known as adaptive prediction. In this review, we summarize environmental variations known to occur in some well-studied models of symbiosis and how these may contribute to the evolution of microbial population heterogeneity and anticipatory behavior. We provide details about the symbiosis between Xenorhabdus bacteria and Steinernema nematodes as a model to investigate the concept of environmental adaptation and adaptive prediction in a microbial symbiosis.

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Section: From the Spent Cadaver To The Ijmentioning

confidence: 91%

Section: From the Ij To The Insectmentioning

confidence: 99%

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Ready or Not: Microbial Adaptive Responses in Dynamic Symbiosis Environments

Cao

Goodrich‐Blair

2017

J Bacteriol

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“…Microscopic analysis reveals both colonization frequency within a population and localization of bacteria to host tissues 14,16,[19][20][21] . This is an advantage over other methods of monitoring bacteria within nematode populations, such as sonication 22 or grinding 23 , which can provide average levels of colonization, but may not, for example, discriminate populations with a high frequency of low symbiont loads from populations with a low frequency of high symbiont loads. Discriminating the frequency and load of colonizing bacteria can be especially important when screening or characterizing bacterial mutants for colonization phenotypes 21,24 .…”

mentioning

confidence: 99%

Visualizing Bacteria in Nematodes using Fluorescent Microscopy

Murfin

Chaston

Goodrich-Blair

2012

JoVE

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Symbioses, the living together of two or more organisms, are widespread throughout all kingdoms of life. As two of the most ubiquitous organisms on earth, nematodes and bacteria form a wide array of symbiotic associations that range from beneficial to pathogenic [1][2][3] . One such association is the mutually beneficial relationship between Xenorhabdus bacteria and Steinernema nematodes, which has emerged as a model system of symbiosis 4 . Steinernema nematodes are entomopathogenic, using their bacterial symbiont to kill insects 5 . For transmission between insect hosts, the bacteria colonize the intestine of the nematode's infective juvenile stage [6][7][8] . Recently, several other nematode species have been shown to utilize bacteria to kill insects [9][10][11][12][13] , and investigations have begun examining the interactions between the nematodes and bacteria in these systems 9 .We describe a method for visualization of a bacterial symbiont within or on a nematode host, taking advantage of the optical transparency of nematodes when viewed by microscopy. The bacteria are engineered to express a fluorescent protein, allowing their visualization by fluorescence microscopy. Many plasmids are available that carry genes encoding proteins that fluoresce at different wavelengths (i.e. green or red), and conjugation of plasmids from a donor Escherichia coli strain into a recipient bacterial symbiont is successful for a broad range of bacteria. The methods described were developed to investigate the association between Steinernema carpocapsae and Xenorhabdus nematophila 14 . Similar methods have been used to investigate other nematode-bacterium associations 9,[15][16][17][18] and the approach therefore is generally applicable.The method allows characterization of bacterial presence and localization within nematodes at different stages of development, providing insights into the nature of the association and the process of colonization 14,16,19 . Microscopic analysis reveals both colonization frequency within a population and localization of bacteria to host tissues 14,16,[19][20][21] . This is an advantage over other methods of monitoring bacteria within nematode populations, such as sonication 22 or grinding 23 , which can provide average levels of colonization, but may not, for example, discriminate populations with a high frequency of low symbiont loads from populations with a low frequency of high symbiont loads. Discriminating the frequency and load of colonizing bacteria can be especially important when screening or characterizing bacterial mutants for colonization phenotypes 21,24 . Indeed, fluorescence microscopy has been used in high throughput screening of bacterial mutants for defects in colonization 17,18 , and is less laborious than other methods, including sonication 22,[25][26][27] and individual nematode dissection 28,29 . Video LinkThe video component of this article can be found at

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“…Colonization of the nematode receptacle is predominantly a monoculture process that is initiated by a single cell followed by bacterial proliferation (24,39). The level of colonization varies from a few cells to several hundreds per nematode and is higher in nematodes reproducing in insects than on bacterial lawns, suggesting that the insect environment provides additional nutrients for bacterial growth (16,39).…”

mentioning

confidence: 99%

OpnS, an Outer Membrane Porin ofXenorhabdus nematophila, Confers a Competitive Advantage for Growth in the Insect Host

Hoeven

Forst

2009

J Bacteriol

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The gammaproteobacterium Xenorhabdus nematophila engages in a mutualistic association with an entomopathogenic nematode and also functions as a pathogen toward different insect hosts. We studied the role of the growth-phase-regulated outer membrane protein OpnS in host interactions. OpnS was shown to be a 16-stranded ␤-barrel porin. opnS was expressed during growth in insect hemolymph and expression was elevated as the cell density increased. When wild-type and opnS deletion strains were coinjected into insects, the wild-type strain was predominantly recovered from the insect cadaver. Similarly, an opnS-complemented strain outcompeted the ⌬opnS strain. Coinjection of the wild-type and ⌬opnS strains together with uncolonized nematodes into insects resulted in nematode progeny that were almost exclusively colonized with the wild-type strain. Likewise, nematode progeny recovered after coinjection of a mixture of nematodes carrying either the wild-type or ⌬opnS strain were colonized by the wild-type strain. In addition, the ⌬opnS strain displayed a competitive growth defect when grown together with the wild-type strain in insect hemolymph but not in defined culture medium. The ⌬opnS strain displayed increased sensitivity to antimicrobial compounds, suggesting that deletion of OpnS affected the integrity of the outer membrane. These findings show that the OpnS porin confers a competitive advantage for the growth and/or the survival of X. nematophila in the insect host and provides a new model for studying the biological relevance of differential regulation of porins in a natural host environment.

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Analysis of the PixA Inclusion Body Protein of Xenorhabdus nematophila

Cited by 28 publications

References 21 publications

Ready or Not: Microbial Adaptive Responses in Dynamic Symbiosis Environments

Ready or Not: Microbial Adaptive Responses in Dynamic Symbiosis Environments

Visualizing Bacteria in Nematodes using Fluorescent Microscopy

OpnS, an Outer Membrane Porin ofXenorhabdus nematophila, Confers a Competitive Advantage for Growth in the Insect Host

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