Project description:BackgroundCooling towers are a major source of large community-associated outbreaks of Legionnaires' disease, a severe pneumonia. This disease is contracted when inhaling aerosols that are contaminated with bacteria from the genus Legionella, most importantly Legionella pneumophila. How cooling towers support the growth of this bacterium is still not well understood. As Legionella species are intracellular parasites of protozoa, it is assumed that protozoan community in cooling towers play an important role in Legionella ecology and outbreaks. However, the exact mechanism of how the eukaryotic community contributes to Legionella ecology is still unclear. Therefore, we used 18S rRNA gene amplicon sequencing to characterize the eukaryotic communities of 18 different cooling towers. The data from the eukaryotic community was then analysed with the bacterial community of the same towers in order to understand how each community could affect Legionella spp. ecology in cooling towers.ResultsWe identified several microbial groups in the cooling tower ecosystem associated with Legionella spp. that suggest the presence of a microbial loop in these systems. Dissolved organic carbon was shown to be a major factor in shaping the eukaryotic community and may be an important factor for Legionella ecology. Network analysis, based on co-occurrence, revealed that Legionella was correlated with a number of different organisms. Out of these, the bacterial genus Brevundimonas and the ciliate class Oligohymenophorea were shown, through in vitro experiments, to stimulate the growth of L. pneumophila through direct and indirect mechanisms.ConclusionOur results suggest that Legionella ecology depends on the host community, including ciliates and on several groups of organisms that contribute to its survival and growth in the cooling tower ecosystem. These findings further support the idea that some cooling tower microbiomes may promote the survival and growth of Legionella better than others. Video Abstract.
Project description:Repairing a damaged body part is critical for the survival of an organism. Tissue damage induces rapid responses to activate downstream events including defense, regeneration and wound healing. Despite accumulating knowledge of early wound signaling including the orchestrated actions of phytohormones, electric circus and reactive oxygen species, our knowledge about the end point of a wound response - wound healing, is still limited. We observed that a local temperature reduction associated with the activation of cold-responsive genes occurred at wounding site on Arabidopsis leaves, which was likely caused by evaporative cooling. The disappearance of localized cooling and restoration of cold responsive genes to a steady state could be used as a quantitative readout of wound healing. Based on these observations, we developed a deep learning pipeline to monitor the dynamics of wound healing. We found that CBFs transcription factors relay injury-induced cooling signal to wound healing. Thus, our work provides a tool to quantify wound healing in plants and advances our understanding of tissue repair in plants.
2025-06-25 | GSE293328 | GEO
Project description:Bacterial communities in a cooling tower
Project description:Common carp (~0.5kg) previously held for over 3 months at 25°C were randomly placed into two large aquarium tanks, one which remained throughout at 25°C (control) and the other was cooled over 3 days to 11°C for 23 days. Replicate specimens from both tanks were then killed at up to 17 timepoints after cooling and kidney tissue was sampled, and ribosomal footprints were quantified as a function of time after cooling using Ribo-Seq.