Search bioRxiv⌕ Search

bioRxiv · 10.1101/602268

Evaluating the quorum quenching potential of bacteria associated to Aurelia aurita and Mnemiopsis leidyi

Abstract

The associated microbiota of marine invertebrates plays an important role to the host in relation to fitness, health and homeostasis of the metaorganism. As one key chemically-mediated interaction, Quorum sensing (QS) and interference with QS among colonizing bacteria ultimately affects the establishment and dynamics of the microbial community on the host. Aiming to address interspecies competition of cultivable microbes associated to merging model species of the basal animal phyla Cnidaria (Aurelia aurita) and Ctenophora (Mnemiopsis leidyi) as well as to evaluate their potential to shape the associated community by interfering with QS, we performed a classical isolation approach. Overall, 84 bacteria were isolated from A. aurita medusae and polyps, 64 bacteria from M. leidyi, and 83 bacteria from the ambient seawater, followed by taxonomically classification by full length 16S rRNA gene analysis. The results show that the moon jellyfish A. aurita and the comb jelly M. leidyi harbor a cultivable core microbiota consisting of typical marine and ubiquitously found bacteria (e.g. Chryseobacter, Microbacterium, Micrococcus, Olleya, Phaeobacter, Pseudoalteromonas, Pseudomonas, Rhodococcus, Shewanella, Staphylococcus, and Vibrio) which can also be found in the ambient seawater. However, several bacteria were restricted to one host (e.g. for A. aurita: Bacillus, Glaciecola, Ruegeria, Luteococcus; for M. leidyi: Acinetobacter, Aeromonas, Colwellia, Exiguobacterium, Marinomonas, Pseudoclavibacter, Psychrobacter, Sagittula, Thalassomonas) suggesting host-specific microbial community patterns. Evaluating QQ activities, out of 231 isolates, 121 showed QS-interfering activity. They mainly interfered with the acyl homoserine lactone (AHL) based communication, whereas 21 showed simultaneous quorum quenching activities against AHL and autoinducer-2. Overall, this study provides insights into the cultivable part of the microbiota associated to two environmentally important marine non-model organisms and discloses their potential in synthesizing QS interfering compounds, potentially important in shaping a healthy and resilient microbiota.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Prasse, D., Weiland-Braeuer, N., Jaspers, C., Reusch, T. B. H., Schmitz-Streit, R. A.. 2019-04-09. Evaluating the quorum quenching potential of bacteria associated to Aurelia aurita and Mnemiopsis leidyi. https://doi.org/10.1101/602268

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Cell-scale confinement reorders bacterial speed rankings

Which bacterium swims fastest depends on where the race is run. Speeds are usually measured in open liquid, yet many bacteria live in pores, mucus and host passages no wider than a cell. Using a microfluidic device with eight channel widths (0.80-3.00 m) in one field of view, we tracked unlabeled cells of eight species spanning five motility systems. Chamber height, a polymer additive and channel width each reordered the ranking. Vibrio alginolyticus, the fastest in open liquid, slowed to ~4 m/s in 1.25-m channels, whereas Campylobacter jejuni and Bacillus subtilis kept 33-46 m/s. Open liquid speed did not predict robustness to confinement. In two unrelated lineages, host symbionts that pass through narrow passages during colonization, Caballeronia insecticola and Vibrio fischeri, outran their non-symbiotic relatives in the channels, and crossed them with flagella wrapped around the cell body at nearly the speed of unwrapped cells. Where space is tight, the ability to keep moving, not top speed, sets the ranking.

microbiology↗

The biochemical composition of coronavirus Nucleocapsid proteins drives the bicistronic properties of their sub-genomic mRNAs

The nucleocapsid (N) gene of coronaviruses (CoVs) encodes a structural RNA-binding protein required for viral assembly. In SARS- and MERS-CoV viruses, reading frame 2 of N contains an overlapping open reading frame (ORF) encoding an innate immune antagonist accessory protein. However, the extent of this dual coding capacity across the CoV family, and the genetic features driving overlapping ORF formation, remain unexamined. Here, we developed an in-silico tool (ORFan) to screen structural gene sub-genomic mRNA sequences from 152 species of coronavirus for the presence of overlapping accessory gene candidates. We found that frame 2 of the N gene in Alpha-, Beta- and Delta-CoVs frequently contains a potential accessory ORF (AcORF), conserved at the subgenus level, unlike the spike, envelope and membrane genes. We also show that CoV nucleotide biases in conjunction with codon biases integral to N protein function drive the relatively high abundances of start codons in frame two and stop codons in frame three, explaining the tendency towards frame 2 AcORFs. We further suggest that viral nucleotide biases and the codon composition required for RNA-binding function facilitate overlapping ORF formation in other virus families

microbiology↗

Evaluating non-oxidative glycolysis using 13C metabolic flux analysis

Non-oxidative glycolysis (NOG) converts glucose to acetyl-CoA without emitting CO2 during Escherichia coli bioproduction. Although 13C-metabolic flux analysis (13C-MFA) has the potential to evaluate NOG flux distribution in vivo, the precision of these estimates depends on the labeling patterns of glucose tracers. Because E. coli has multiple native glycolysis pathways, selecting the optimal glucose tracer is important for precise estimates. This study used simulations to evaluate the performance of 18 commercially available glucose tracers in precisely predicting NOG flux. We artificially generated flux distributions of central metabolic pathways, including three types of NOG pathways, and obtained 13C labeling patterns of amino acids metabolized from each glucose tracer. Using these data, we then calculated 95% confidence intervals (CIs) for NOG pathway fluxes. Comparing the sum of CI widths from three NOG fluxes showed that estimation with [1,3-13C]-glucose yielded the narrowest CIs. Several tracers, including [2,3-13C]glucose, were capable of determining fluxes with high precision, but [1-13C]glucose was not one of them, despite often being used for estimating glycolytic fluxes. We then experimentally evaluated [2,3-13C]- and [1-13C]glucose as tracers in E. coli strains with and without the expression of phosphoketolase, which is required for NOG pathways to function. The results suggested that [1-13C]glucose could not detect NOG fluxes, whereas [2,3-13C]glucose estimated the fluxes of all three NOG pathways with narrow CIs.

microbiology↗