Haloferax volcanii, a model halophilic (salt-loving) archaeon, showed growth during a 160-day experiment simulating Martian subsurface brine, according to a paper published in the journal Applied and ...

Haloferax volcanii, a model halophilic (salt-loving) archaeon, showed growth during a 160-day experiment simulating Martian subsurface brine, according to a paper published in the journal Applied and...

IntroductionDon Juan Pond (DJP), located in the McMurdo Dry Valleys of Antarctica, is one of the most extreme cold aquatic environments on our planet and mos...

The search for cellular life is a major objective of future Mars exploration. While many studies have examined whether microorganisms can survive under Martian conditions, far fewer have demonstrated ...

Introduction: Don Juan Pond (DJP), located in the McMurdo Dry Valleys of Antarctica, is one of the most extreme cold aquatic environments on our planet and m...

Microbial biogeography has recently attracted significant attention for its potential to provide novel ecological and evolutionary insights

Host-virus interactions remain poorly understood in archaea, whose information processing systems harbor a mosaic of bacterial and eukaryotic features. Here, we used complementary multiomics to investigate interactions between Haloferax tailed virus 1 (HFTV1) and the halophilic archaeon Haloferax gibbonsii (Hg), capturing global translational and transcriptional dynamics across the infection cycle. This revealed co-regulatory expression patterns across HFTV1 and Hg genes. Post-transcriptional regulation was observed for several early HFTV1 genes and the late HFTV1 gene gp17, and the HFTV1 tRNA co-sedimented with Hg ribosome complexes. Infection reshaped the translational landscape of Hg, causing a slow decline in information processing activity, a complex transcriptional response, and amino acid starvation. An unannotated Tat-dependent fimbrial system of Hg was co-regulated with early HFTV1 genes and was correlated with increased biofilm formation, suggesting a potential antiviral defense system. These findings provide high-resolution insight into archaeal host-virus interactions at the evolutionary interface between bacteria and eukaryotes. ### Competing Interest Statement The authors have declared no competing interest. U.S. National Science Foundation, MCB-57951

A Gram-stain-negative, aerobic, moderately halophilic, non-motile, rod-shaped bacterium, designated MC10-B4T, was isolated from the coral Oulastrea crispata collected from Hong Kong waters. The strain showed the ability to persist in a coral holobiont during an eight-month monitoring period in a field trial, indicating a long-term association with the coral host. Growth occurred at 10-37 °C (optimum, 28-30 °C), at NaCl concentrations up to 4.0% (w/v; optimum, 0.5-2.0%), and at pH 7.0-10.0 (optimum, pH 7.0-8.0) under standard laboratory conditions. Colonies on Marine Agar 2216 were round, smooth, convex, white, opaque, and had entire margins. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain MC10-B4T belongs to the genus Ruegeria and shares the highest sequence similarity with Ruegeria conchae TW15T (99.64%), followed by Ruegeria profundi ZGT108T (98.92%), Ruegeria lacuscaerulensis ITI-1157T (98.46%), Ruegeria denitrificans CECT 5091T (98.31%), Ruegeria arenilitoris G-M8T (97.69%), Ruegeria atlantica NBRC 15792T (97.55%), Ruegeria halocynthiae MA1-6 (97.11%), Ruegeria atlantica IAM 14463T (96.98%), Ruegeria meonggei MA-E2-3 (96.83%), and Ruegeria pomeroyi DSS-3T (96.65%). Genome sequencing revealed a genome size of 4.55 Mbp and a DNA G+C content of 57.5 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain MC10-B4T and Ruegeria conchae TW15T were 77.6% and 18.2-22.8%, respectively. These values are below the recommended thresholds for species delineation (95% and 70%). Strain MC10-B4T shares the same predominant fatty acid, summed feature 8 (consisting of C18:1 ω7c and/or C18:1 ω6c), with other Ruegeria strains; however, it also contains C19:0 cyclo ω8c, which was not detected in Ruegeria conchae TW15T and Ruegeria pomeroyi DSS-3T. The type strain is MC10-B4T (= GDMCC 1.6889T = KCTC 18785T). ### Competing Interest Statement The authors have declared no competing interest. Hong Kong Research Grants Council (RGC) General Research Fund, 14114724 Coral Research and Development Accelerator Platform (CORDAP), CAP-2024-1692

Abstract. Microbial biogeography has recently attracted significant attention for its potential to provide novel ecological and evolutionary insights, with

The present-day martian surface is generally considered inhospitable to life because of low atmospheric pressure

Haloferax volcanii DSM27206 is an archaeon belonging to the Halobacteriaceae family isolated from a solar saltern in Alexandria (1, 2). Haloferax volcanii TMT produces canthaxanthin and can accumulate...