Biosynthesis and function of 7-deazaguanine derivatives in bacteria and phages

Deazaguanine modifications play multifaceted roles in the molecular biology of DNA and tRNA, shaping diverse yet essential biological processes, including the nuanced fine-tuning of translation efficiency and the intricate modulation of codon-anticodon interactions. Beyond their roles in translation, deazaguanine modifications contribute to cellular stress resistance, self-nonself discrimination mechanisms, and host evasion defenses, directly modulating the adaptability of living organisms. Deazaguanine moieties extend beyond nucleic acid modifications, manifesting in the structural diversity of biologically active natural products. Their roles in fundamental cellular processes and their presence in biologically active natural products underscore their versatility and pivotal contributions to the intricate web of molecular interactions within living organisms. Here, we discuss the current understanding of the biosynthesis and multifaceted functions of deazaguanines, shedding light on their diverse and dynamic roles in the molecular landscape of life

Novel genomic island modifies DNA with 7-deazaguanine derivatives

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Dynamics of Baltic Sea phages driven by environmental changes

Phage predation constitutes a major mortality factor for bacteria in aquatic ecosystems, and thus, directly impacts nutrient cycling and microbial community dynamics. Yet, the population dynamics of specific phages across time scales from days to months remain largely unexplored, which limits our understanding of their influence on microbial succession. To investigate temporal changes in diversity and abundance of phages infecting particular host strains, we isolated 121 phage strains that infected three bacterial hosts during a Baltic Sea mesocosm experiment. Genome analysis revealed a novel Flavobacterium phage genus harboring gene sets putatively coding for synthesis of modified nucleotides and glycosylation of bacterial cell surface components. Another novel phage genus revealed a microdiversity of phage species that was largely maintained during the experiment and across mesocosms amended with different nutrients. In contrast to the newly described Flavobacterium phages, phages isolated from a Rheinheimera strain were highly similar to previously isolated genotypes, pointing to genomic consistency in this population. In the mesocosm experiment, the investigated phages were mainly detected after a phytoplankton bloom peak. This concurred with recurrent detection of the phages in the Baltic Proper during summer months, suggesting an influence on the succession of heterotrophic bacteria associated with phytoplankton blooms

\uab Les linguistiques du d\ue9tachement. Actes du Colloque International de Nancy (7-9 juin 2006) \ubb. Collection SCIENCES POUR LA COMMUNICATION, Peter Lang, Berne, 2009, N\ub0 87, p. 595.

Le num\ue9ro 87 de la collection SCIENCES POUR LA COMMUNICATION est consacr\ue9 \ue0 la publication des actes du Colloque International \uab Les linguistiques du d\ue9tachement \ubb qui s\u2019est tenu \ue0 Nancy les 7-9 juin 2006. Ce colloque, dont l\u2019organisation a \ue9t\ue9 assur\ue9e par l\u2019ATILF (Analyse et Traitement Informatique de la Langue Fran\ue7aise, CNRS et Nancy-Universit\ue9s) et par le laboratoire CRISCO (Centre de Recherches Inter-langues sur la Signification en Contexte, Universit\ue9 de Caen), avait le but de r\ue9unir tous les chercheurs s\u2019int\ue9ressant aux structures \uab \ue0 d\ue9tachement \ubb, c\u2019est-\ue0-dire aux phrases dites DISLOQU\uc9ES ou SEGMENT\uc9ES (dislocation \ue0 droite ou \ue0 gauche), mais aussi \ue0 l\u2019apposition et \ue0 d\u2019autres formes de discontinuit\ue9 syntaxique. S\u2019agissant de constructions qui se r\ue9alisent, avec de fortes ressemblances, dans l\u2019ensemble des syst\ue8mes linguistiques, les organisateurs ont veill\ue9 \ue0 ce que la plus grande vari\ue9t\ue9 de langues soit repr\ue9sent\ue9e, souhaitant aboutir, au-del\ue0 des difformit\ue9s th\ue9oriques et terminologiques, \ue0 une typologie des constructions \uab \ue0 d\ue9tachement \ubb. Les actes du colloque r\ue9pertorient donc tant les \ue9tudes portant sur l\u2019\ue9crit que celles sur l\u2019oral conversationnel, et pr\ue9sentent, en m\ueame temps, un \ue9chantillonnage repr\ue9sentatif des diff\ue9rents niveaux d\u2019analyse (syntaxique, s\ue9mantique, pragmatique, prosodique), du point de vue adopt\ue9 (synchronique ou diachronique) et des mod\ue8les th\ue9oriques de r\ue9f\ue9rence. En raison de leur grand nombre, les 41 contributions seront r\ue9parties ici par grandes aires th\ue9matiques ainsi que par niveau de saillance et/ou de repr\ue9sentativit\ue9 \ue0 l\u2019int\ue9rieur de chaque aire