<i><scp>V</scp>ibrio<scp>f</scp>ischeri</i>–Squid Symbiosis

Tischler, Alice H.; Hodge‐Hanson, Kelsey; Visick, Karen L.

doi:10.1002/9780470015902.a0028395

Cited by 8 publications

(9 citation statements)

References 56 publications

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“…The first contact between host and microbe occurs in mucus that covers the symbiotic organ in this species‐specific association (Schwartzman and Ruby, ). The mildly acidic pH of the squid mucus is one of several initial cues presented to symbiotic cells during their transition from the planktonic state to host association (Wang and Ruby, ; Kremer et al , ; Tischler et al, ) . Because V. fischeri cells aggregate in this mucus immediately before encountering a multitude of chemical assaults from the squid, we hypothesized that acidic pH serves as an important cue to induce defensive responses from V. fischeri as it establishes its exclusive relationship with the host.…”

Section: Introductionmentioning

confidence: 99%

Acidic pH promotes lipopolysaccharide modification and alters colonization in a bacteria–animal mutualism

Schwartzman

Lynch

Ramos

et al. 2019

Molecular Microbiology

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Summary Environmental pH can be an important cue for symbiotic bacteria as they colonize their eukaryotic hosts. Using the model mutualism between the marine bacterium Vibrio fischeri and the Hawaiian bobtail squid, we characterized the bacterial transcriptional response to acidic pH experienced during the shift from planktonic to host‐associated lifestyles. We found several genes involved in outer membrane structure were differentially expressed based on pH, indicating alterations in membrane physiology as V. fischeri initiates its symbiotic program. Exposure to host‐like pH increased the resistance of V. fischeri to the cationic antimicrobial peptide polymixin B, which resembles antibacterial molecules that are produced by the squid to select V. fischeri from the ocean microbiota. Using a forward genetic screen, we identified a homolog of eptA, a predicted phosphoethanolamine transferase, as critical for antimicrobial defense. We used MALDI‐MS to verify eptA as an ethanolamine transferase for the lipid‐A portion of V. fischeri lipopolysaccharide. We then used a DNA pulldown approach to discover that eptA transcription is activated by the global regulator H‐NS. Finally, we revealed that eptA promotes successful squid colonization by V. fischeri, supporting its potential role in initiation of this highly specific symbiosis.

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Section: Introductionmentioning

confidence: 99%

Acidic pH promotes lipopolysaccharide modification and alters colonization in a bacteria–animal mutualism

Schwartzman

Lynch

Ramos

et al. 2019

Molecular Microbiology

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“…In principle, habitat changes likely exist on a spectrum ranging from very recent (on the order of minutes or days) to extremely ancient (on the order of billions or millions of years). In the wellstudied Vibrio fischeri-bobtail squid (Euprymna scolopes) symbiosis, bacterial symbionts are recruited from surrounding seawater to the animal tissues at the onset of symbiosis (98). Subsequently, at the beginning of each day, approximately 90% of Vibrio cells are vented out of the light organ back to their original planktonic niche (72).…”

Section: Timescales Relevant For Habitat Transitionmentioning

confidence: 99%

“…Subsequently, at the beginning of each day, approximately 90% of Vibrio cells are vented out of the light organ back to their original planktonic niche (72). Thus, in contrast to rarer events observed in other lineages, habitat transitions occur nearly constantly for V. fischeri and, remarkably, are accompanied by apparently reversible changes to cell size and motility structures (81,98). Similar dynamics are also observable in other horizontally transmitted symbioses such as those in marine mollusks, annelids, and root nodules of terrestrial plants (10).…”

Section: Timescales Relevant For Habitat Transitionmentioning

confidence: 99%

Habitat Transition in the Evolution of Bacteria and Archaea

Jaffe

Castelle

Banfield

2023

Annu. Rev. Microbiol.

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Related groups of microbes are widely distributed across Earth's habitats, implying numerous dispersal and adaptation events over evolutionary time. However, relatively little is known about the characteristics and mechanisms of these habitat transitions, particularly for populations that reside in animal microbiomes. Here, we review the literature concerning habitat transitions among a variety of bacterial and archaeal lineages, considering the frequency of migration events, potential environmental barriers, and mechanisms of adaptation to new physicochemical conditions, including the modification of protein inventories and other genomic characteristics. Cells dependent on microbial hosts, particularly bacteria from the Candidate Phyla Radiation, have undergone repeated habitat transitions from environmental sources into animal microbiomes. We compare their trajectories to those of both free-living cells—including the Melainabacteria, Elusimicrobia, and methanogenic archaea—and cellular endosymbionts and bacteriophages, which have made similar transitions. We conclude by highlighting major related topics that may be worthy of future study. Expected final online publication date for the Annual Review of Microbiology, Volume 77 is September 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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“…The symbionts are housed in the dedicated light organ (LO) within the squid’s mantle cavity, where they generate light that the host uses for counterillumination to hide its shadow while hunting at night ( 18 ). The host provides the symbionts with a protected niche, nutrients, and oxygen ( 15 ). Once the symbiosis is irreversibly established in juvenile squid, a daily cycle proceeds where 90 to 95% of the bacteria are expelled from the LO at dawn.…”

Section: Introductionmentioning

confidence: 99%