Enhancing closure efficacy in antireflux mucoplasty through endoscopic hand-suturing technique.

Video 1XXX.

Analysis of microbial dynamics in the soybean root-associated environments from community to single-cell levels.

Plant root-associated environments such as the rhizosphere, rhizoplane, and endosphere, are notably different from non-root-associated soil environments. However, the microbial dynamics in these spatially divided compartments remain unexplored. In this study, we propose a combinational analysis of single-cell genomics with 16S rRNA gene sequencing. This method enabled us to understand the entire soil microbiome and individual root-associated microorganisms. We applied this method to soybean microbiomes and revealed that their composition was different between the rhizoplane and rhizosphere in the early growth stages, but became more similar as growth progressed. In addition, a total of 610 medium- to high-quality single-amplified genomes (SAGs) were acquired, including plant growth-promoting rhizobacteria (PGPR) candidates while genomes with high GC content tended to be missed by SAGs. The whole-genome analyses of the SAGs suggested that rhizoplane-enriched Flavobacterium solubilizes organophosphate actively and Bacillus colonizes roots more efficiently. Single-cell genomics, together with 16S rRNA gene sequencing, enabled us to connect microbial taxonomy and function, and assess microorganisms at a strain resolution even in the complex soil microbiome.

Endoscopic pressure study integrated system using an ultrathin gastroscope for the functional assessment of the lower esophageal sphincter.

OBJECTIVES: The endoscopic pressure study integrated system (EPSIS) represents an innovative approach for evaluating lower esophageal sphincter function by monitoring intragastric pressure using diagnostic gastroscopes. This study aimed to assess the feasibility and validity of employing ultrathin gastroscopes for EPSIS. METHODS: A retrospective analysis was conducted on a database of consecutive patients who underwent EPSIS using both ultrathin and regular gastroscopes between September 2021 and October 2023. The study compared EPSIS parameters between the two gastroscope types to evaluate the correlation of key metrics. RESULTS: Thirty patients underwent EPSIS with both ultrathin and regular gastroscopes. Significant positive correlations were observed in the pressure waveform: maximum intragastric pressure (mmHg) (ρ = 0.82, P < 0.001) and intragastric pressure gradient (mmHg/s) (ρ = 0.80, P < 0.001) when comparing the two gastroscopes. Maximum intragastric pressure (15.5 [5.3-20.3] vs. 18.5 [3.4-21.6], P < 0.001) and pressure gradient (0.16 [0.013-0.41] vs. 0.24 [0.0039-1.13], P < 0.001), (median [range]) were significantly lower with ultrathin gastroscopes. CONCLUSIONS: This study establishes that EPSIS parameters obtained with an ultrathin gastroscope exhibit a significant correlation with those obtained using a regular gastroscope, with each EPSIS parameter consistently lower. These findings support the viability of EPSIS for ultrathin gastroscopy and highlight its potential as a diagnostic tool for assessing lower esophageal sphincter function.

Tools for microbial single-cell genomics for obtaining uncultured microbial genomes.

The advent of next-generation sequencing technologies has facilitated the acquisition of large amounts of DNA sequence data at a relatively low cost, leading to numerous breakthroughs in decoding microbial genomes. Among the various genome sequencing activities, metagenomic analysis, which entails the direct analysis of uncultured microbial DNA, has had a profound impact on microbiome research and has emerged as an indispensable technology in this field. Despite its valuable contributions, metagenomic analysis is a "bulk analysis" technique that analyzes samples containing a wide diversity of microbes, such as bacteria, yielding information that is averaged across the entire microbial population. In order to gain a deeper understanding of the heterogeneous nature of the microbial world, there is a growing need for single-cell analysis, similar to its use in human cell biology. With this paradigm shift in mind, comprehensive single-cell genomics technology has become a much-anticipated innovation that is now poised to revolutionize microbiome research. It has the potential to enable the discovery of differences at the strain level and to facilitate a more comprehensive examination of microbial ecosystems. In this review, we summarize the current state-of-the-art in microbial single-cell genomics, highlighting the potential impact of this technology on our understanding of the microbial world. The successful implementation of this technology is expected to have a profound impact in the field, leading to new discoveries and insights into the diversity and evolution of microbes.

Comparative single-cell genomics of Atribacterota JS1 in the Japan Trench hadal sedimentary biosphere.

Deep-sea and subseafloor sedimentary environments host heterotrophic microbial communities that contribute to Earth's carbon cycling. However, the potential metabolic functions of individual microorganisms and their biogeographical distributions in hadal ocean sediments remain largely unexplored. In this study, we conducted single-cell genome sequencing on sediment samples collected from six sites (7,445-8,023 m water depth) along an approximately 500 km transect of the Japan Trench during the International Ocean Discovery Program Expedition 386. A total of 1,886 single-cell amplified genomes (SAGs) were obtained, offering comprehensive genetic insights into sedimentary microbial communities in surface sediments (<1 m depth) above the sulfate-methane transition zone along the Japan Trench. Our genome data set included 269 SAGs from Atribacterota JS1, the predominant bacterial clade in these hadal environments. Phylogenetic analysis classified SAGs into nine distinct phylotypes, whereas metagenome-assembled genomes were categorized into only two phylotypes, advancing JS1 diversity coverage through a single cell-based approach. Comparative genomic analysis of JS1 lineages from different habitats revealed frequent detection of genes related to organic carbon utilization, such as extracellular enzymes like clostripain and α-amylase, and ABC transporters of oligopeptide from Japan Trench members. Furthermore, specific JS1 phylotypes exhibited a strong correlation with in situ methane concentrations and contained genes involved in glycine betaine metabolism. These findings suggest that the phylogenomically diverse and novel Atribacterota JS1 is widely distributed in Japan Trench sediment, playing crucial roles in carbon cycling within the hadal sedimentary biosphere.IMPORTANCEThe Japan Trench represents tectonically active hadal environments associated with Pacific plate subduction beneath the northeastern Japan arc. This study, for the first time, documented a large-scale single-cell and metagenomic survey along an approximately 500 km transect of the Japan Trench, obtaining high-quality genomic information on hadal sedimentary microbial communities. Single-cell genomics revealed the predominance of diverse JS1 lineages not recoverable through conventional metagenomic binning. Their metabolic potential includes genes related to the degradation of organic matter, which contributes to methanogenesis in the deeper layers. Our findings enhance understanding of sedimentary microbial communities at water depths exceeding 7,000 m and provide new insights into the ecological role of biogeochemical carbon cycling in the hadal sedimentary biosphere.

Clinical outcomes of anti-reflux mucosal ablation for gastroesophageal reflux disease: An international bi-institutional study.

BACKGROUND AND AIM: Anti-reflux mucosal ablation (ARMA) is an emerging endoscopic treatment aimed at enhancing the gastroesophageal junction flap valve. This study aimed to evaluate its feasibility, effectiveness, and safety. METHODS: Between May 2018 and December 2022, patients with gastroesophageal reflux disease (GERD) symptoms refractory to acid suppression medications or those dependent on such medications were enrolled for ARMA. This retrospective analysis utilized prospectively collected data from an international bi-center study. GERD questionnaire, upper endoscopy, and 24-h pH monitoring were conducted at 2-6 months and 12 months post-ARMA. Clinical success was defined as a > 50% reduction in a validated GERD questionnaire. RESULTS: A total of 68 patients underwent ARMA. Definitive GERD was diagnosed in 44 (64.7%) patients, while 24 (35.3%) exhibited reflux hypersensitivity. Clinical success rates at 2-6 months and 1 year post-ARMA were 60% (39/65) and 70% (21/30), respectively. The median GERD-health-related quality of life score significantly improved from 26 to 11 at 2-6 months (P < 0.001). Among the 51 patients (71.8%) who underwent 24-h pH monitoring, the median acid exposure time decreased from 5.3% to 0.7% (P = 0.003), accompanied by a significant reduction in esophagitis rates (P < 0.001). Multivariate analysis did not identify predictors of short-term success. Nine (13.2%) patients experienced transient stenosis requiring balloon dilation. CONCLUSIONS: ARMA demonstrates both technical feasibility and reproducibility as a safe procedure that effectively ameliorates GERD symptoms in approximately two-thirds of patients during short-term follow up. Both reflux hypersensitivity and confirmed GERD patients, regardless of their response to acid suppression medication, may be suitable candidates.

Feasibility and safety of per-oral endoscopic septotomy for Killian-Jamieson diverticulum: Case series with video.

BACKGROUND AND AIMS: Killian-Jamieson diverticulum (KJD) is a relatively uncommon variant of pharyngoesophageal diverticula, distinct from the more prevalent Zenker diverticulum. However, literature on endoscopic management of KJD remains limited. This study aimed to elucidate the efficacy and safety of peroral endoscopic septotomy (POES) as a treatment approach for symptomatic KJD. METHODS: In this retrospective observational study, we investigated the outcomes of nine consecutive patients who underwent POES for KJD between January 2019 and May 2023. Follow-up data of at least 2 months post-treatment were analyzed. The primary outcome measure was the technical success rate of POES. Secondary outcomes encompassed the clinical success rate, defined as symptomatic improvement 2 months after POES, and the incidence of adverse events. RESULTS: All patients presented with dysphagia, with a median symptom duration of 6 months (interquartile range [IQR]: 3-12 months). The median diverticulum size was 32 mm (IQR: 24-42 mm). The median duration of the operation time was 66 min (IQR: 60-109). A 100% technical success rate was achieved, with complete closure of the defect in all cases. There were no adverse events related to this treatment. The median hospitalization duration was 5 days (IQR: 4-6), and the clinical success rate was 88.9%. Follow-up barium esophagograms exhibited significant improvement in the flow of the barium for all patients. CONCLUSIONS: Despite the relatively limited case volume, our findings underscore that POES is a safe and efficacious approach for managing symptomatic KJD.

Hood attached vs conventional triangular tip-jet knife in peroral endoscopic myotomy: a propensity score matching cohort study.

BACKGROUND & AIM: Peroral endoscopic myotomy (POEM) is a safe and effective endoscopic treatment for achalasia and other esophageal motility disorders, and TTJ (Triangle Tip Knife J; Olympus, Tokyo, Japan) is currently widely used in POEM. Recently, we reported a novel modification of TTJ, which was adjusted to knife length 2 mm by attaching a disposable clip (QuickClip Pro; Olympus) sheath to the tip as a hood attachment. In this study, we compared the safety and effectiveness of TTJ and TTJ with hood attachment (TTJ-H) in POEM. METHODS: In this 1:1 propensity score matched retrospective cohort study, we compared the procedure time, myotomy efficiency, number of coagulation forceps usage, adverse events, length of hospital stay after POEM, procedural success and clinical success between TTJ and TTJ-H groups. RESULTS: We examined 682 consecutive patients who underwent POEM between January 2021 and June 2023. We excluded 134 patients who had already undergone POEM or laparoscopic Heller myotomy as prior myotomy. Finally, we identified 98 propensity score-matched pairs (n = 196). The mean procedure time was shortened from 93.5 to 80.2 min (14% reduction, P = 0.012) when comparing TTJ-H group to TTJ group. The mean myotomy efficiency was improved from 2.76 to 2.32 min/cm (16% improvement, P = <0.001), and usage of coagulation forceps for hemostasis was decreased from 3.87 to 0.55 (86% reduction, P = <0.001). CONCLUSIONS: This study showed that use of TTJ-H could reduce total procedure time, improve myotomy efficiency, and reduce costs compared to TTJ.

Antireflux mucoplasty, an evolution of endoscopic antireflux therapy for refractory GERD.

Video 1We present a new therapeutic approach called antireflux mucoplasty for proton pump inhibitor-refractory GERD.

Maximizing limited space: usefulness of percutaneous cricothyrotomy and super-soft hood for hypopharyngeal endoscopic submucosal dissection.

Video 1Demonstration of the usefulness of percutaneous cricothyrotomy and a super-soft hood for hypopharyngeal endoscopic submucosal dissection.

Endoscopic mucoplasty for benign esophageal strictures (multiple Schatzki rings).

Video 1Demonstration of endoscopic mucoplasty for benign esophageal strictures (multiple Schatzki rings).

Triangle-tip jet knife with hood attachment: novel modification to endoscopic knife.

Video 1Triangle-tip jet knife with hood attachment: a novel modification over existing endoscopic knife.

Pilot study on anti-reflux mucoplasty: Advancing endoscopic anti-reflux therapy for gastroesophageal reflux disease.

OBJECTIVES: Anti-reflux mucosectomy (ARMS) and anti-reflux mucosal ablation (ARMA) were developed as interventions for proton pump inhibitor (PPI)-refractory/-dependent gastroesophageal reflux disease (GERD). Although ARMS and ARMA are established treatments for PPI-refractory GERD, reliance on natural healing for ulcer scar formation introduces uncertainty and bleeding risk. To address these issues, we introduced a novel approach called anti-reflux mucoplasty (ARM-P), which involves immediate closure of mucosal defects following mucosectomy. This pilot study aims to evaluate the safety, feasibility, and efficacy of ARM-P. METHODS: A retrospective single-center study was conducted using prospectively collected data from October 2022 to July 2023. Patients with PPI-refractory/-dependent GERD who underwent ARM-P were included. The study evaluated technical success of ARM-P, before and after ARM-P GERD-Health Related Quality of Life Questionnaire, GerdQ, and Frequency Scale for the Symptoms of GERD scores, along with PPI discontinuation and endoscopic esophagogastric junction morphology. RESULTS: A total of 20 patients with a median age of 61.5 years underwent the ARM-P procedure. The procedure achieved 100% technical success without adverse events. After ARM-P, 55.0% discontinued PPI usage and 15.0% reduced PPI dose by half. Median GERD-Health Related Quality of Life Questionnaire score improved from 21 to 6 (P = 0.0026), median GerdQ score improved from 9 to 7 (P = 0.0022), and median Frequency Scale for the Symptoms of GERD score decreased from 16 to 7 (P = 0.0003). Median Hill's Classification significantly improved from grade III to grade I (P = 0.0001). CONCLUSIONS: This study presents the first pilot report of ARM-P, demonstrating its procedural safety, technical feasibility, and short-term efficacy.

Endoscopic pressure study integrated system for the diagnosis of achalasia.

OBJECTIVES: The endoscopic pressure study integrated system (EPSIS) is a novel diagnostic tool used to evaluate lower esophageal sphincter (LES) function. EPSIS allows the measurement of intragastric pressure (IGP) during gastric insufflation through esophagogastroduodenoscopy (EGD) and records its pressure waveform. This study aimed to assess the usefulness and applicability of EPSIS as an adjunct diagnostic modality for achalasia. METHODS: This case-control study was conducted using a database of patients who underwent EGD, barium swallow (BS), high-resolution manometry (HRM), and EPSIS between January 2022 and December 2022. The achalasia (experimental) group (n = 35) consisted of patients with a definitive diagnosis of achalasia. The control group (n = 34) consisted of patients with no abnormalities in EGD, BS, or HRM and no abnormal acid reflux confirmed with 24-h pH-impedance monitoring. EPSIS findings were compared between the two groups and characterized by the waveform pattern (uphill or flat), maximum IGP (IGP-Max), pressure difference, and the gradient of the waveform. RESULTS: All patients in the achalasia group showed an uphill pattern, in contrast to 21 patients (61.8%) in the control group. IGP-Max demonstrated the best diagnostic accuracy for achalasia, with a cut-off value of 15.8 mmHg (100% sensitivity, 58.8% specificity, and area under the curve [AUC] 0.78). The pressure gradient also demonstrated good diagnostic accuracy, with a cut-off value of 0.40 mmHg/s (80% sensitivity, 61.8% specificity, and AUC 0.76). CONCLUSION: This study demonstrated that EPSIS can be applied as a diagnostic modality in patients with achalasia.

Endoscopic carbon dioxide insufflation tolerance test on the anal sphincter for anorectal hypofunction: a pilot and feasibility study.

Background: Anorectal function deteriorates with age. The diagnostic performance of the endoscopic pressure study integrated system (EPSIS), an endoscopic carbon dioxide (CO2) insufflation stress test of the lower esophageal sphincter has been previously evaluated as a diagnostic tool for gastroesophageal reflux disease. We aimed to evaluate the applicability of EPSIS in improving anorectal function. We hypothesized that EPSIS can be applied to the diagnosis of lower gastrointestinal tract disorders. Methods: This was a pilot, single-center, retrospective study using prospectively collected data between December 2021 and March 2022. It was designed to evaluate the differences in EPSIS rectal pressure measurements between older (≥80 years) and younger (<80 years) patients. At the end of the screening colonoscopy, the colonoscope was fixed in a retroflex position. When bowel movement was observed, CO2 was insufflated to the point where gas leakage occurred through the anus. The measured maximum pressure was defined as EPSIS-rectal pressure max (EPSIS-RP max) and compared between the groups. Results: Overall, 30 patients were included and examined. The median ages of the <80 and ≥80 years' groups were 53 (range: 27-79) and 82 (range: 80-94) years, respectively, with corresponding median measured EPSIS-RP max of 18.7 (range: 8.5-30.2) and 9.8 (range: 5.4-22.3) mmHg (P<0.001). Conclusions: Measurement of maximum rectal pressure illustrates the age-related decline in physiological anorectal function. Future studies should consider a loading test using EPSIS to quantify the decline in anorectal function and use it as a routine tool for screening and adjunctive diagnosis of anorectal hypofunction.

Determination of esophageal squamous cell carcinoma and gastric adenocarcinoma on raw tissue using Raman spectroscopy.

BACKGROUND: Cancer detection is a global research focus, and novel, rapid, and label-free techniques are being developed for routine clinical practice. This has led to the development of new tools and techniques from the bench side to routine clinical practice. In this study, we present a method that uses Raman spectroscopy (RS) to detect cancer in unstained formalin-fixed, resected specimens of the esophagus and stomach. Our method can record a clear Raman-scattered light spectrum in these specimens, confirming that the Raman-scattered light spectrum changes because of the histological differences in the mucosal tissue. AIM: To evaluate the use of Raman-scattered light spectrum for detecting endoscop-ically resected specimens of esophageal squamous cell carcinoma (SCC) and gastric adenocarcinoma (AC). METHODS: We created a Raman device that is suitable for observing living tissues, and attempted to acquire Raman-scattered light spectra in endoscopically resected specimens of six esophageal tissues and 12 gastric tissues. We evaluated formalin-fixed tissues using this technique and captured shifts at multiple locations based on feasibility, ranging from six to 19 locations 200 microns apart in the vertical and horizontal directions. Furthermore, a correlation between the obtained Raman scattered light spectra and histopathological diagnosis was performed. RESULTS: We successfully obtained Raman scattered light spectra from all six esophageal and 12 gastric specimens. After data capture, the tissue specimens were sent for histopathological analysis for further processing because RS is a label-free methodology that does not cause tissue destruction or alterations. Based on data analysis of molecular-level substrates, we established cut-off values for the diagnosis of esophageal SCC and gastric AC. By analyzing specific Raman shifts, we developed an algorithm to identify the range of esophageal SCC and gastric AC with an accuracy close to that of histopathological diagnoses. CONCLUSION: Our technique provides qualitative information for real-time morphological diagnosis. However, further in vivo evaluations require an excitation light source with low human toxicity and large amounts of data for validation.

Combined actions of bacteriophage-encoded genes in Wolbachia-induced male lethality.

Some Wolbachia endosymbionts induce male killing, whereby male offspring of infected females are killed during development; however, the origin and diversity of the underlying mechanisms remain unclear. In this study, we identified a 76 kbp prophage region specific to male-killing Wolbachia hosted by the moth Homona magnanima. The prophage encoded a homolog of the male-killing gene oscar in Ostrinia moths and the wmk gene that induces various toxicities in Drosophila melanogaster. Upon overexpressing these genes in D. melanogaster, wmk-1 and wmk-3 killed all males and most females, whereas Hm-oscar, wmk-2, and wmk-4 had no impact on insect survival. Strikingly, co-expression of tandemly arrayed wmk-3 and wmk-4 killed 90% of males and restored 70% of females, suggesting their conjugated functions for male-specific lethality. While the male-killing gene in the native host remains unknown, our findings highlight the role of bacteriophages in male-killing evolution and differences in male-killing mechanisms among insects.

Revealing within-species diversity in uncultured human gut bacteria with single-cell long-read sequencing.

Obtaining complete and accurate bacterial genomes is vital for studying the characteristics of uncultured bacteria. Single-cell genomics is a promising approach for the culture-independent recovery of bacterial genomes from individual cells. However, single-amplified genomes (SAGs) often have fragmented and incomplete sequences due to chimeric and biased sequences introduced during the genome amplification process. To address this, we developed a single-cell amplified genome long-read assembly (scALA) workflow to construct complete circular SAGs (cSAGs) from long-read single-cell sequencing data of uncultured bacteria. We used the SAG-gel platform, which is both cost-effective and high-throughput, to obtain hundreds of short-read and long-read sequencing data for specific bacterial strains. The scALA workflow generated cSAGs by repeated in silico processing for sequence bias reduction and contig assembly. From 12 human fecal samples, including two cohabitant groups, scALA generated 16 cSAGs of three specifically targeted bacterial species: Anaerostipes hadrus, Agathobacter rectalis, and Ruminococcus gnavus. We discovered strain-specific structural variations shared among cohabiting hosts, while all cSAGs of the same species showed high homology in aligned genomic regions. A. hadrus cSAGs exhibited 10 kbp-long phage insertions, various saccharide metabolic capabilities, and different CRISPR-Cas systems in each strain. The sequence similarity of A. hadrus genomes did not necessarily correspond with orthologous functional genes, while host geographical regionality seemed to be highly related to gene possession. scALA allowed us to obtain closed circular genomes of specifically targeted bacteria from human microbiota samples, leading to an understanding of within-species diversities, including structural variations and linking mobile genetic elements, such as phages, to hosts. These analyses provide insight into microbial evolution, the adaptation of the community to environmental changes, and interactions with hosts. cSAGs constructed using this method can expand bacterial genome databases and our understanding of within-species diversities in uncultured bacteria.

Learning curve for peroral endoscopic myotomy in therapeutic endoscopy experts and nonexperts: Large single-center experience.

OBJECTIVES: Reports on learning curve for peroral endoscopic myotomy (POEM) in therapeutic endoscopy nonexperts are limited. We aimed to assess the number of cases required to achieve POEM proficiency for endoscopic submucosal dissection (ESD) experts and nonexperts. METHODS: This is a retrospective study at the largest POEM referral center in Japan. POEM between April 2014 and December 2020 were included. Nonexperts and ESD experts were divided by training phases: A, 1-20; B, 21-40; C, 41-60; D, 61-80; and E, 81-100 cases. Primary outcome was operation time, and the phase to reach target time (83 min) was investigated. Secondary outcomes were clinical success rate, adverse events, and post-POEM gastroesophageal reflux disease (GERD). RESULTS: Five hundred and sixty-six cases were performed by 14 nonexperts, and 555 cases by 15 ESD experts. As the primary outcome, operation time in nonexperts was: A, 95 (79-115.8); B, 86.5 (71-105); C, 80 (70-100); D, 73 (64.5-100.5); and E, 73.5 (57.8-88.8) min, while in ESD experts: A, 90 (74-128); B, 77 (70-92); and C, 77 (70-93.5) min (median [interquartile range]). Operation time decreased significantly as experience increased in both groups (P < 0.001), and nonexperts required 41-60 cases to achieve proficiency, while experts required 21-40 cases. As secondary outcomes, in nonexperts, clinical success was 96.9-100%, adverse events were 5.0-9.2%, symptomatic GERD was 11.8-26.5%, and proton pump inhibitor (PPI) intake was 11.5-18.7% in each phase. While in experts, clinical success was 96.2-100%, adverse events were 3.0-5.8%, symptomatic GERD was 14.6-22.0%, and PPI intake was 12.6-17.9%. There were no significant differences among training phases. CONCLUSIONS: Non-ESD experts require more cases to achieve proficiency in POEM. These results are useful for establishing POEM training programs and institutional implementation of the procedure.

Targeted single-cell genomics reveals novel host adaptation strategies of the symbiotic bacteria Endozoicomonas in Acropora tenuis coral.

BACKGROUND: Endozoicomonas bacteria symbiosis with various marine organisms is hypothesized as a potential indicator of health in corals. Although many amplicon analyses using 16S rRNA gene have suggested the diversity of Endozoicomonas species, genome analysis has been limited due to contamination of host-derived sequences and difficulties in culture and metagenomic analysis. Therefore, the evolutionary and functional potential of individual Endozoicomonas species symbiotic with the same coral species remains unresolved. RESULTS: In this study, we applied a novel single-cell genomics technique using droplet microfluidics to obtain single-cell amplified genomes (SAGs) for uncultured coral-associated Endozoicomonas spp. We obtained seven novel Endozoicomonas genomes and quantitative bacterial composition from Acropora tenuis corals at four sites in Japan. Our quantitative 16S rRNA gene and comparative genomic analysis revealed that these Endozoicomonas spp. belong to different lineages (Clade A and Clade B), with widely varying abundance among individual corals. Furthermore, each Endozoicomonas species possessed various eukaryotic-like genes in clade-specific genes. It was suggested that these eukaryotic-like genes might have a potential ability of different functions in each clade, such as infection of the host coral or suppression of host immune pathways. These Endozoicomonas species may have adopted different host adaptation strategies despite living symbiotically on the same coral. CONCLUSIONS: This study suggests that coral-associated Endozoicomonas spp. on the same species of coral have different evolutional strategies and functional potentials in each species and emphasizes the need to analyze the genome of each uncultured strain in future coral-Endozoicomonas relationships studies. Video Abstract.