Biology subjects

Suzuki, M. T.

Publications and source records attributed to Suzuki, M. T..

3 recordsLinked to original sources

bioRxiv2025

Symbiont diversity and light-organ morphology in Sepiola affinis

The squid-vibrio symbiosis has illuminated fundamental mechanisms of beneficial animal-microbe associations, yet the interactions within sepiolid squid in the Mediterranean Sea remain underexplored. Here we characterize the Sepiola affinis squid-vibrio symbiosis by combining whole-genome sequencing of light-organ isolates, confocal microscopy, and temperature-dependent growth assays. Comparative genomic analyses (ANI, phylogenomics, and functional analyses) revealed two previously undescribed Vibrio species associated with the S. affinis light organ. One species clusters more distantly from other Vibrio while the other species is closer to established Vibrio clades, with the second species exhibiting an expanded repertoire of mobile elements and Type VI secretion components, suggesting heightened capacity for genetic exchange and interbacterial interaction. Confocal microscopy of juvenile squid established that the S. affinis light organ comprises twelve crypts connected by pores and ducts, expanding the number of symbiotic niches relative to other sepiolid squid. In addition, fluorescently labeled isolates from the two Vibrio species colonized juveniles in both mono- and co-colonization patterns within crypts. Finally, growth assays across 16-24{degrees}C identified species-specific temperature differences, indicating temperature preference that may align with seasonal variability in the Mediterranean Sea. Together, these findings position S. affinis as a tractable model for studying how symbiont diversity, organ architecture, and interbacterial interactions contribute to the stability of a mutualistic symbiosis.

microbiology↗

bioRxiv2021

Integrated metabolomic, molecular networking and genome mining analyses uncover novel angucyclines from Streptomyces sp. RO-S4 isolated from Bejaia Bay, Algeria

Multi-omic approaches have recently made big strides towards the effective exploration of microorganisms and accelerating the discovery of new bioactive compounds. We combined metabolomic, molecular networking, and genomic-based approaches to investigate the metabolic potential of the Streptomyces sp. RO-S4 strain isolated from the polluted waters of Bejaia Bay in Algeria. Antagonistic assays against methicillin-resistant Staphylococcus aureus with RO-S4 organic extracts showed an inhibition zone of 20 mm by the agar diffusion method, and its minimum inhibitory concentration was 16 g/mL. A molecular network was created using GNPS and annotated through the comparison of MS/MS spectra against several databases. The predominant compounds in the RO-S4 extract belonged to the angucyclines family. Three compounds were annotated as known metabolites, while all the others were putatively new to Science. Notably, all compounds had fridamycin-like aglycones, and several of them had a lactonized D ring analogous to that of urdamycin L. The whole genome of Streptomyces RO-S4 was sequenced to identify the biosynthetic gene cluster (BGC) encoding for these angucyclines, which yielded a draft genome of 7,497,846 bp with 72.4% G+C content. Subsequently, a genome mining analysis revealed 19 putative biosynthetic gene clusters, including a grincamycin-like BGC with a high similarity to that of Streptomyces sp. CZN-748 previously reported to also produce mostly open fridamycin-like aglycones. As the ring-opening process leading to these compounds is still not defined, we performed comparative analysis with other angucycline BGCs and advanced some hypotheses to explain the ring-opening and lactone formation, possibly linked to the uncoupling between the activity of GcnE and GcnM homologues in the RO-S4 strain. The combination of metabolomic and genomic approaches greatly improved the interpretation of the metabolic potential of the RO-S4 strain.

microbiology↗

bioRxiv2017

Marine cyanolichens from different littoral zones are associated with distinct bacterial communities

The microbial diversity and function of terrestrial lichens has been well studied, but knowledge about the non-photosynthetic bacteria associated with marine lichens is still scarce. 16S rRNA gene Illumina sequencing was used to assess the culture-independent bacterial diversity in the strictly marine cyanolichen species Lichina pygmaea and Lichina confinis, and the maritime chlorolichen species Xanthoria aureola which occupy different areas on the littoral zone. Inland terrestrial cyanolichens from Austria were also analysed as for the marine lichens to examine further the impact of habitat/lichen species on the associated bacterial communities. The L. confinis and L. pygmaea communities were significantly different from those of the maritime Xanthoria aureola lichen found higher up on the littoral zone and these latter communities were more similar to those of the inland terrestrial lichens. The strictly marine lichens were dominated by the Bacteroidetes phylum accounting for 50% of the sequences, whereas Alphaproteobacteria, notably Sphingomonas, dominated the maritime and the inland terrestrial lichens. Bacterial communities associated with the two Lichina species were significantly different sharing only 33 core OTUs, half of which were affiliated to the Bacteroidetes genera Rubricoccus, Tunicatimonas and Lewinella, suggesting an important role of these species in the marine Lichina lichen symbiosis. Marine cyanolichens showed a higher abundance of OTUs likely affiliated to moderately thermophilic and/or radiation resistant bacteria belonging to the Phyla Chloroflexi, Thermi, and the families Rhodothermaceae and Rubrobacteraceae when compared to those of inland terrestrial lichens. This most likely reflects the exposed and highly variable conditions to which they are subjected daily.

ecology↗