Project description:This dataset contains several sponge-derived bacteria, along with data from the sponges to enable the assignation of the biosynthetic source of detected metabolite features. Media controls and solvent blanks are also included. Please see metadata for the bacterial source sponge.
2022-10-28 | MSV000090609 | MassIVE
Project description:Sponge associated bacteria community
Project description:Chemotaxis is used by free-living motile bacteria to swim towards nutrient sources or away from repellents, and to navigate the environment to locate niches optimal for growth and survival. Multiple chemotaxis systems have been identified in different bacterial species, including Azospirillum brasilense. In A. brasilense, chemotaxis is mediated by two distinct chemotaxis pathways, named Che1 and Che4, that physically interact to form mixed chemotaxis signaling arrays. Signaling from the Che1 and Che4 pathways control transient increases in swimming speed and swimming reversals, respectively, during chemotaxis. In A. brasilense, chemotaxis is tightly linked to energy metabolism with this coupling occurring through the sensory input of several energy-sensing chemoreceptors and through the control of chemoreceptor activity by the c-di-GMP second messenger. Previous work has demonstrated that chemotaxis in A. brasilense also affects unrelated cellular functions including cell-to-cell clumping and flocculation. However, the molecular mechanism for these effects is not known. Here, we identify additional effects of mutations abolishing Che1 (cheA1 mutant), Che4 (cheA4 mutant) or both Che1 and Che4 (cheA1/cheA4 mutant) function on nitrogen and carbon metabolism and use whole cell proteome and metabolome mass spectrometry to further characterize the interplay between chemotaxis and metabolism. We found that CheA1 mediates most changes in chemoreceptor arrays composition and also affects small molecules signaling while a mutant lacking CheA4 displays changes in nitrogen metabolism, including nitrate assimilation and nitrogen fixation. In contrast, the mutant lacking both CheA1 and CheA4, which lacks chemotaxis and does not form chemotaxis signaling arrays, displays distinct and non-overlapping changes that suggest the assembly of chemotaxis signaling arrays modulates energy and carbon metabolism. Together, the results suggest distinct roles for CheA1, CheA4 and chemotaxis signaling arrays in modulating chemotaxis and metabolism, likely through control of distinct global regulatory networks.
2020-08-25 | MSV000086008 | MassIVE
Project description:Sponge -associated Bacteria and Fungi
Project description:miRNA sponge, a special class of miRNA target, has been emerging as a pivotal player in miRNA mediated regulatory network. Currently, the identified miRNA sponge genes mostly act on sequestering conserved miRNAs (e.g. miR-7, miR-145), however, the existence, potential function and evolutionary process of miRNA sponge genes for species-specific miRNA, especially for human specific miRNA, are largely unknown. In this study, we conducted a systematic analysis including sponge gene identification and subsequent function and evolutionary analyses for an authentic human-specific miRNA, miR-941.
Project description:Chemotaxis is a widespread strategy used by unicellular and multicellular living organisms to maintain their fitness in stressful environments. We previously showed that bacteria can trigger a negative chemotactic response to a copper (Cu)-rich environment. Cu ions toxicity on bacterial cell physiology has been mainly linked to mismetallation events and ROS production, although the precise role of Cu-generated ROS remains largely debated. Here, we found that the cytoplasmic Cu ions content mirrors variations of the extracellular Cu ions concentration and triggers a dose-dependent oxidative stress, which can be abrogated by superoxide dismutase and catalase overexpression. The inhibition of ROS production in the cytoplasm not only improves bacterial growth but also impedes Cu-chemotaxis, indicating that ROS derived from cytoplasmic Cu ions mediate the control of bacterial chemotaxis to Cu. We also identified the Cu chemoreceptor McpR, which binds Cu ions with low affinity, suggesting a labile interaction. In addition, we demonstrate that the cysteine 75 and histidine 99 within the McpR sensor domain are key residues in Cu chemotaxis and Cu coordination. Finally, we discovered that in vitro both Cu(I) and Cu(II) ions modulate McpR conformation in a distinct manner. Overall,our study provides mechanistic insights on a redox-based control of Cu chemotaxis, indicating that the cellular redox status can play a key role in bacterial chemotaxis.