One carbon (C1) metabolism plays an important role in marine carbon cycling but the dynamics and modes of C1 transformations are not fully understood. We made contemporaneous measurements of methylamine and methanol metabolism to elucidate the role of C1 compounds as sources of carbon, energy and nitrogen. Methanol and methylamine were predominantly used as an energy source in offshore waters (oxidation rate constant: k : 0.02-0.10 day ; k : 0.01-0.18 day ), but were also important sources of biomass carbon in coastal waters (assimilation rate constant: k : 0.04-0.10 day ; k : 0.01-0.05 day ). The relative extent of assimilation versus oxidation for these substrates correlated positively with chlorophyll, nutrients and heterotrophic bacterial production. Methanol oxidation and assimilation were stimulated significantly by nutrient addition. In contrast, methylamine metabolism was inhibited by ammonium or nitrate, suggesting that methylamine served as a nitrogen source. A preliminary metagenomic survey revealed a diverse population of putative C1-utilizing microorganisms. These results show that the remineralization of methylamine could provide both C and N sources for microbes. Both methanol and methylamine contribute to microbial energetic and carbon substrate demands with a distinctly different signature in nearshore versus offshore environments.

Lysinibacillus sphaericus strain OT4b.31 is a native Colombian strain having no larvicidal activity against Culex quinquefasciatus and is widely applied in the bioremediation of heavy-metal polluted environments. Strain OT4b.31 was placed between DNA homology groups III and IV. By gap-filling and alignment steps, we propose a 4,096,672 bp chromosomal scaffold. The whole genome (consisting of 4,856,302 bp long, 94 contigs and 4,846 predicted protein-coding sequences) revealed differences in comparison to the L. sphaericus C3-41 genome, such as syntenial relationships, prophages and putative mosquitocidal toxins. Sphaericolysin B354, the coleopteran toxin Sip1A and heavy metal resistance clusters from nik, ars, czc, cop, chr, czr and cad operons were identified. Lysinibacillus sphaericus OT4b.31 has applications not only in bioremediation efforts, but also in the biological control of agricultural pests.

Lysinibacillus sphaericus CBAM5, was isolated from subsurface soil of oil well explorations in the Easter Planes of Colombia. This strain has potential in bioremediation of heavy-metal polluted environments and biological control of Culex quinquefasciatus. According to the phylogenetic analysis of 16S rRNA gene sequences, the strain CBAM5 was assigned to the Lysinibacillus sphaericus taxonomic group 1 that comprises mosquito pathogenic strains. After a combination assembly-integration, alignment and gap-filling steps, we propose a 4,610,292 bp chromosomal scaffold. The whole genome (consisting of 5,146,656 bp long, 60 contigs and 5,209 predicted-coding sequences) revealed strong functional and syntenial similarities to the L. sphaericus C3-41 genome. Mosquitocidal (Mtx), binary (Bin) toxins, cereolysin O, and heavy metal resistance clusters from nik, ars, czc, mnt, ter, cop, cad, and znu operons were identified.

Acetate is a key intermediate of organic matter mineralization, but its metabolism remains largely unconstrained in the pelagic ocean. We conducted an integrated biogeochemical study to investigate microbial acetate cycling in the northern Gulf of Mexico with the goal of elucidating the importance of acetate as a carbon and energy source. Acetate was used primarily as an energy source, as evidenced by observed oxidation rates (rate constant k: 0.06–0.22 day−1) that varied between 42% and 96% of total biological acetate uptake (i.e., assimilation + oxidation; k: 0.06–0.34 day−1). The assimilation of acetate into biomass (k: 0.01–0.20 day−1) illustrated the potential significance of acetate as a biomass carbon source, particularly in nutrient‐rich coastal waters. No relationship between acetate assimilation or oxidation and environmental factors, such as chlorophyll and nutrients, was observed. However, elevated acetate uptake in reduced oxygen waters characterized by particulate organic carbon mineralization suggests that acetate metabolism may be a good proxy for particulate organic carbon breakdown. Molecular genetic analysis revealed that SAR11 Alphaproteobacteria were the most abundant heterotrophic bacteria and suggest that they may utilize acetate. At some sites, acetate carbon may have accounted for up to 50.4% of the bacterial carbon production. These results suggest that acetate may serve as an important carbon and energy source for heterotrophic bacteria thus revealing a potentially significant role of acetate for dissolved organic carbon cycling in the ocean.

Hydrocarbon-degrading bacteria are phylogenetically and physiologically diverse and employ layered strategies to sense hydrocarbons, respond transcriptionally, and then move toward an oil source. They then produce biopolymers that increase hydrocarbon bioavailability. This SnapShot highlights how these bacteria respond to and then remove hydrocarbon contaminants from the environment. To view this SnapShot, open or download the PDF.