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1. Draft genome sequence of Exiguobacterium sp. strain MMG028 isolated from a salt marsh

   https://doi.org/10.1128/mra.00116-23  

   Farrell, Morgan V; Airkin, Mina Y; Ali, Tatyana N; Altoblani, Zainalabdin S; Bowman, Chynna R; Diaz, Abigail_Anne B; Faurot, Paul F; Frausto, Joshua E; Haji, Sazan F; Hamad, Basma A; et al (March 2024, Microbiology Resource Announcements)

   Stewart, Frank J (Ed.)

   ABSTRACT Here, we report the draft genome sequence ofExiguobacteriumsp. strain MMG028, isolated from Rose Creek, San Diego, CA, USA, assembled and analyzed by undergraduate students participating in a marine microbial genomics course. A genomic comparison suggests that MMG028 is a novel species, providing a resource for future microbiology and biotechnology investigations. 

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2. Draft genome sequences of Flagellimonas sp. MMG031 and Marinobacter sp. MMG032 isolated from the dinoflagellate Symbiodinium pilosum

   https://doi.org/10.1128/mra.00913-24  

   Farrell, Morgan V; Aljaber, Aya M; Amoruso, Madison; Chan, Wyman F; Dael, Jiellen R; De_Tomas, Mathieu L; Delavega, Emily G; Eslava, Jacob M; Holdbrook-Smith, Benjamin J; Lee, Precilla; et al (January 2025, Microbiology Resource Announcements)

   Roux, Simon (Ed.)

   ABSTRACT Here, we report the draft genome sequences ofFlagellimonassp. MMG031 andMarinobactersp. MMG032, isolated from coral-associated dinoflagellateSymbiodinium pilosum, assembled and analyzed by undergraduate students participating in a Marine Microbial Genomics (MMG) course. A genomic comparison suggests MMG031 and MMG032 are novel species and a resource for restoration and biotechnology. 

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3. Draft genome sequence of Methanocalculus natronophilus sp. strain Z-7105 ^T , an alkaliphilic, methanogenic archaeon isolated from a soda lake

   https://doi.org/10.1128/mra.00350-24  

   Elkassas, Sabrina M; Serres, Margrethe H; Richardson, Derrick; Zhilina, Tatyana N; Huber, Julie A (July 2024, Microbiology Resource Announcements)

   Roux, Simon (Ed.)

   ABSTRACT A methanogenic archaeon was isolated from bottom sediments in the vicinity of Lake Tanatar II (Altai, Russia), an alkaline soda lake. Here we present the draft genome sequence ofMethanocalculus natronophilussp. strain Z-7105^T. 

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4. Pontiella agarivorans sp. nov., a novel marine anaerobic bacterium capable of degrading macroalgal polysaccharides and fixing nitrogen

   https://doi.org/10.1128/aem.00914-23  

   Liu, Na; Kivenson, Veronika; Peng, Xuefeng; Cui, Zhisong; Lankiewicz, Thomas S; Gosselin, Kelsey M; English, Chance J; Blair, Elaina M; O'Malley, Michelle A; Valentine, David L (February 2024, Applied and Environmental Microbiology)

   Glass, Jennifer B (Ed.)

   ABSTRACT Marine macroalgae produce abundant and diverse polysaccharides, which contribute substantially to the organic matter exported to the deep ocean. Microbial degradation of these polysaccharides plays an important role in the turnover of macroalgal biomass. Various members of thePlanctomycetes-Verrucomicrobia-Chlamydia(PVC) superphylum are degraders of polysaccharides in widespread anoxic environments. In this study, we isolated a novel anaerobic bacterial strain NLcol2^Tfrom microbial mats on the surface of marine sediments offshore Santa Barbara, CA, USA. Based on 16S ribosomal RNA (rRNA) gene and phylogenomic analyses, strain NLcol2^Trepresents a novel species within thePontiellagenus in theKiritimatiellotaphylum (within the PVC superphylum). Strain NLcol2^Tis able to utilize various monosaccharides, disaccharides, and macroalgal polysaccharides such as agar and ɩ-carrageenan. A near-complete genome also revealed an extensive metabolic capacity for anaerobic degradation of sulfated polysaccharides, as evidenced by 202 carbohydrate-active enzymes (CAZymes) and 165 sulfatases. Additionally, its ability of nitrogen fixation was confirmed by nitrogenase activity detected during growth on nitrogen-free medium, and the presence of nitrogenases (nifDKH) encoded in the genome. Based on the physiological and genomic analyses, this strain represents a new species of bacteria that may play an important role in the degradation of macroalgal polysaccharides and with relevance to the biogeochemical cycling of carbon, sulfur, and nitrogen in marine environments. Strain NLcol2^T(= DSM 113125^T= MCCC 1K08672^T) is proposed to be the type strain of a novel species in thePontiellagenus, and the namePontiella agarivoranssp. nov. is proposed.IMPORTANCEGrowth and intentional burial of marine macroalgae is being considered as a carbon dioxide reduction strategy but elicits concerns as to the fate and impacts of this macroalgal carbon in the ocean. Diverse heterotrophic microbial communities in the ocean specialize in these complex polymers such as carrageenan and fucoidan, for example, members of theKiritimatiellotaphylum. However, only four type strains within the phylum have been cultivated and characterized to date, and there is limited knowledge about the metabolic capabilities and functional roles of related organisms in the environment. The new isolate strain NLcol2^Texpands the known substrate range of this phylum and further reveals the ability to fix nitrogen during anaerobic growth on macroalgal polysaccharides, thereby informing the issue of macroalgal carbon disposal. 

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5. FurC (PerR) contributes to the regulation of peptidoglycan remodeling and intercellular molecular transfer in the cyanobacterium Anabaena sp. strain PCC 7120

   https://doi.org/10.1128/mbio.03231-23  

   Sarasa-Buisan, Cristina; Nieves-Morión, Mercedes; Arévalo, Sergio; Helm, Richard F.; Sevilla, Emma; Luque, Ignacio; Fillat, María F. (March 2024, mBio)

   Brennan, Richard Gerald (Ed.)

   ABSTRACT Microbial extracellular proteins and metabolites provide valuable information concerning how microbes adapt to changing environments. In cyanobacteria, dynamic acclimation strategies involve a variety of regulatory mechanisms, being ferric uptake regulator proteins as key players in this process. In the nitrogen-fixing cyanobacteriumAnabaenasp. strain PCC 7120, FurC (PerR) is a global regulator that modulates the peroxide response and several genes involved in photosynthesis and nitrogen metabolism. To investigate the possible role of FurC in shaping the extracellular environment ofAnabaena, the analysis of the extracellular metabolites and proteins of afurC-overexpressing variant was compared to that of the wild-type strain. There were 96 differentially abundant proteins, 78 of which were found for the first time in the extracellular fraction ofAnabaena. While these proteins belong to different functional categories, most of them are predicted to be secreted or have a peripheral location. Several stress-related proteins, including PrxA, flavodoxin, and the Dps homolog All1173, accumulated in the exoproteome offurC-overexpressing cells, while decreased levels of FurA and a subset of membrane proteins, including several export proteins andamiCgene products, responsible for nanopore formation, were detected. Direct repression by FurC of some of those genes, includingamiC1andamiC2,could account for odd septal nanopore formation and impaired intercellular molecular transfer observed in thefurC-overexpressing variant. Assessment of the exometabolome from both strains revealed the release of two peptidoglycan fragments infurC-overexpressing cells, namely 1,6-anhydro-N-acetyl-β-D-muramic acid (anhydroMurNAc) and its associated disaccharide (β-D-GlcNAc-(1-4)-anhydroMurNAc), suggesting alterations in peptidoglycan breakdown and recycling.IMPORTANCECyanobacteria are ubiquitous photosynthetic prokaryotes that can adapt to environmental stresses by modulating their extracellular contents. Measurements of the organization and composition of the extracellular milieu provide useful information about cyanobacterial adaptive processes, which can potentially lead to biomimetic approaches to stabilizing biological systems to adverse conditions.Anabaenasp. strain PCC 7120 is a multicellular, nitrogen-fixing cyanobacterium whose intercellular molecular exchange is mediated by septal junctions that traverse the septal peptidoglycan through nanopores. FurC (PerR) is an essential transcriptional regulator inAnabaena, which modulates the response to several stresses. Here, we show thatfurC-overexpressing cells result in a modified exoproteome and the release of peptidoglycan fragments. Phenotypically, important alterations in nanopore formation and cell-to-cell communication were observed. Our results expand the roles of FurC to the modulation of cell-wall biogenesis and recycling, as well as in intercellular molecular transfer. 

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