Locality and diel cycling of viral production revealed by a 24 h time course cross-omics analysis in a coastal region of Japan

International audienceViruses infecting microorganisms are ubiquitous and abundant in the ocean. However, it is unclear when and where the numerous viral particles we observe in the sea are produced and whether they are active. To address these questions, we performed time-series analyses of viral metagenomes and microbial metatranscriptomes collected over a period of 24 h at a Japanese coastal site. Through mapping the metatranscriptomic reads on three sets of viral genomes ((i) 878 contigs of Osaka Bay viromes (OBV), (ii) 1766 environmental viral genomes from marine viromes, and (iii) 2429 reference viral genomes), we revealed that all the local OBV contigs were transcribed in the host fraction. This indicates that the majority of viral populations detected in viromes are active, and suggests that virions are rapidly diluted as a result of diffusion, currents, and mixing. Our data further revealed a peak of cyanophage gene expression in the afternoon/dusk followed by an increase of genomes from their virions at night and less-coherent infectious patterns for viruses putatively infecting various groups of heterotrophs. This suggests that cyanophages drive the diel release of cyanobacteria-derived organic matter into the environment and viruses of heterotrophic bacteria might have adapted to the population-specific life cycles of hosts

Genomic adaptation of giant viruses in polar oceans

寒冷域と温暖域ではウイルスの遺伝子組成が異なる --巨大ウイルスの環境適応--. 京都大学プレスリリース. 2023-10-13.Despite being perennially frigid, polar oceans form an ecosystem hosting high and unique biodiversity. Various organisms show different adaptive strategies in this habitat, but how viruses adapt to this environment is largely unknown. Viruses of phyla Nucleocytoviricota and Mirusviricota are groups of eukaryote-infecting large and giant DNA viruses with genomes encoding a variety of functions. Here, by leveraging the Global Ocean Eukaryotic Viral database, we investigate the biogeography and functional repertoire of these viruses at a global scale. We first confirm the existence of an ecological barrier that clearly separates polar and nonpolar viral communities, and then demonstrate that temperature drives dramatic changes in the virus–host network at the polar–nonpolar boundary. Ancestral niche reconstruction suggests that adaptation of these viruses to polar conditions has occurred repeatedly over the course of evolution, with polar-adapted viruses in the modern ocean being scattered across their phylogeny. Numerous viral genes are specifically associated with polar adaptation, although most of their homologues are not identified as polar-adaptive genes in eukaryotes. These results suggest that giant viruses adapt to cold environments by changing their functional repertoire, and this viral evolutionary strategy is distinct from the polar adaptation strategy of their hosts

Clinical Characteristics and Outcomes in 314 Japanese Patients with Bacterial Endophthalmitis : A Multicenter Cohort Study from J-CREST

Bacterial endophthalmitis is an intraocular infection that causes rapid vison loss. Pathogens can infect the intraocular space directly (exogenous endophthalmitis (ExE)) or indirectly (endogenous endophthalmitis (EnE)). To identify predictive factors for the visual prognosis of Japanese patients with bacterial endophthalmitis, we retrospectively examined the bacterial endophthalmitis characteristics of 314 Japanese patients and performed statistics using these clinical data. Older patients, with significantly more severe clinical symptoms, were prevalent in the ExE group compared with the EnE group. However, the final best-corrected visual acuity (BCVA) was not significantly different between the ExE and EnE groups. Bacteria isolated from patients were not associated with age, sex, or presence of eye symptoms. Genus Streptococcus, Streptococcus pneumoniae, and Enterococcus were more prevalent in ExE patients than EnE patients and contributed to poor final BCVA. The presence of eye pain, bacterial identification, and poor BCVA at baseline were risk factors for final visual impairment

IOP elevation after STTA

Purpose To evaluate real-world evidence for intraocular pressure (IOP) elevation after subtenon triamcinolone acetonide injection (STTA) in 1252 Japanese patients (1406 eyes) in the Japan Clinical REtina STudy group (J-CREST). Methods This was a multicentre retrospective study of the medical records of 1252 patients (676 men (758 eyes); mean age: 63.8 ± 12.9 years) who received STTA in participating centres between April 2013 and July 2017. Results IOP elevation was observed in 206 eyes (14.7%) and IOP increase ≥ 6 mmHg was found in 328 eyes (23.3%). In total, 106 eyes (7.5%) needed medication and two eyes (0.14%) needed surgical procedures. Younger age, higher baseline IOP, and steroid dose were risk factors associated with IOP elevation. Risk factors associated with IOP increase ≥ 6 mmHg were younger age, lower baseline IOP, steroid dose, and higher incidences of diabetic macular oedema (DME) and uveitis. In contrast, with steroid dose fixed at 20 mg, a lower incidence of DME was a risk factor for increased IOP, suggesting that STTA had dose-dependent effects on IOP increase, especially in patients with DME. Conclusion Our real-world evidence from a large sample of Japanese patients who received STTA showed that the incidence of IOP elevation after STTA was 14.7%, and was associated with younger age, higher baseline IOP, and steroid dose. Thus, IOP should be monitored, especially in patients with younger age, higher baseline IOP, and higher incidences of DME and uveitis