Project description:Chromosome segregation is a vital process for all organisms. The mechanisms underpinning chromosomal partitioning in the archaeal domain remain elusive. Our group has identified the first chromosome segregation system in thermophilic archaea. Sulfolobus solfataricus partition system consists of SegA, an orthologue of bacterial Walker-type ParA proteins; SegB, an archaea-specific DNA binding protein and a cis-acting DNA region. ChIP-seq experiments disclosed multiple SegB binding sites scattered over the chromosome and revealed a novel DNA binding motif.
Project description:Thermococcales are an order of archaea that inhabit the sulfur-rich, anaerobic environments of deep-sea hydrothermal vents. Their metabolism shifts toward the production of hydrogen sulfide (H₂S) in the presence of elemental sulfur. As a gaseous signaling molecule, H₂S primarily regulates biological processes by mediating the S-sulfhydration of protein cysteine. However, it remains unknown whether such modifications occur in these archaea. In this study, we employed chemical proteomics to systematically identify S-sulfhydration sites in the deep-sea hyperthermophilic archaeon Thermococcus aciditolerans SY113. This approach revealed unique reactivity characteristics of the modification and allowed quantitative analysis of its dynamic regulation by H₂S. A total of 204 S-sulfhydration sites on 171 proteins were identified, over 65% of which were dynamically regulated by H₂S. Further functional analysis indicated that S-sulfhydration plays an ancient and conserved role in primordial cells, including the regulation of catalytic activity, maintenance of protein conformation, and mediation of protein-protein interactions. Our findings provide a valuable dataset and theoretical foundation for understanding the role of S-sulfhydration in the physiological regulation of deep-sea hyperthermophilic archaea.
Project description:Ammonia-oxidizing archaea (AOA) have been reported at high abundance in much of the global ocean, even in environments such as pelagic oxygen minimum zones (OMZs), where conditions seem unlikely to support aerobic ammonium oxidation. Due to the lack of information on any potential alternative metabolism of AOA, the AOA community composition might be expected to differ between oxic and anoxic environments, indicating some difference in ecology and/or physiology of the AOA assemblage. This hypothesis was tested by evaluating AOA community composition using a functional gene microarray that targets the ammonia monooxygenase gene subunit A (amoA). The relationship between environmental parameters and the biogeography of the Arabian Sea and the Eastern Tropical South Pacific (ETSP) AOA assemblages was investigated using principal component analysis (PCA) and redundancy analysis (RDA). In both the Arabian Sea and the ETSP, AOA communities within the core of the OMZ were not significantly different from those inhabiting the oxygenated surface waters above the OMZ. The AOA communities in the Arabian Sea were significantly different from those in the ETSP. In both oceans, the abundance of archaeal amoA gene in the core of the OMZ was higher than that in the surface waters. Our results indicate that AOA communities are distinguished by their geographic origin. RDA suggested that temperature was the main factor that correlated with the differences between the AOA communities from the Arabian Sea and those from the ETSP. Physicochemical properties that characterized the different environments of the OMZ and surface waters played a less important role than did geography in shaping the AOA community composition. Two-color array (Cy3 and Cy5): the universal standard 20-mer oligo is printed to the slide with a 70-mer oligo (an archetype). Environmental DNA sequences (fluoresced with Cy3) within 15% of the 70-mer conjugated to a 20-mer oligo (fluoresced with Cy5) complementary to the universal standard will bind to the oligo probes on the array. Signal is the ratio of Cy3 to Cy5. Three replicate probes were printed for each archetype. Two replicate arrays were run on duplicate targets.
Project description:Ammonia-oxidizing archaea (AOA) have been reported at high abundance in much of the global ocean, even in environments such as pelagic oxygen minimum zones (OMZs), where conditions seem unlikely to support aerobic ammonium oxidation. Due to the lack of information on any potential alternative metabolism of AOA, the AOA community composition might be expected to differ between oxic and anoxic environments, indicating some difference in ecology and/or physiology of the AOA assemblage. This hypothesis was tested by evaluating AOA community composition using a functional gene microarray that targets the ammonia monooxygenase gene subunit A (amoA). The relationship between environmental parameters and the biogeography of the Arabian Sea and the Eastern Tropical South Pacific (ETSP) AOA assemblages was investigated using principal component analysis (PCA) and redundancy analysis (RDA). In both the Arabian Sea and the ETSP, AOA communities within the core of the OMZ were not significantly different from those inhabiting the oxygenated surface waters above the OMZ. The AOA communities in the Arabian Sea were significantly different from those in the ETSP. In both oceans, the abundance of archaeal amoA gene in the core of the OMZ was higher than that in the surface waters. Our results indicate that AOA communities are distinguished by their geographic origin. RDA suggested that temperature was the main factor that correlated with the differences between the AOA communities from the Arabian Sea and those from the ETSP. Physicochemical properties that characterized the different environments of the OMZ and surface waters played a less important role than did geography in shaping the AOA community composition.