We report a general method based on wide-field fluorescence imaging of single molecule photobleaching and the Chung-Kennedy algorithm to measure the stoichiometry of functional protein complexes in living bacterial cells.
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http://dx.doi.org/10.1039/c0cc01707h | DOI Listing |
Ecology
January 2025
Department of Biology, Baylor University, Waco, Texas, USA.
Ecosystem-scale primary production may be proximately limited by nitrogen (N) but ultimately limited by phosphorus (P) because N fixation contributes new N that accumulates relative to P at ecosystem scales. However, the duration needed to transition between proximate N limitation and ultimate P limitation remains unknown for most ecosystems, including lakes. Here we present the results of a fully replicated, multi-annual lake mesocosm experiment that permitted full air-water-sediment interactions that mimicked lake ecosystem ecology.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Ecology and Evolution, University of Chicago, Chicago, IL 60637.
Many proteins form paralogous multimers-molecular complexes in which evolutionarily related proteins are arranged into specific quaternary structures. Little is known about the mechanisms by which they acquired their stoichiometry (the number of total subunits in the complex) and heterospecificity (the preference of subunits for their paralogs rather than other copies of the same protein). Here, we use ancestral protein reconstruction and biochemical experiments to study historical increases in stoichiometry and specificity during the evolution of vertebrate hemoglobin (Hb), an αβ heterotetramer that evolved from a homodimeric ancestor after a gene duplication.
View Article and Find Full Text PDFAnal Methods
January 2025
Department of Chemistry, Karpagam Academy of Higher Education, Coimbatore, Tamil Nadu, India.
A new rhodamine based turn on florescent probe ()-3',6'-bis(ethylamino)-2-(((6-methoxy-2-oxo-1,2-dihydroquinolin-3-yl)methylene)amino)-2',7'-dimethylspiro[isoindoline-1,9'-xanthen]-3-one (RME) was efficiently synthesized through a simple condensation reaction of 2-amino-3',6'-bis(ethylamino)-2',7'-dimethylspiro[isoindoline-1,9'-xanthen]-3-one and 6-methoxy-2-oxo-1,2-dihydroquinoline-3-carbaldehyde. The receptor RME is highly non-fluorescent and when copper ions (Cu ions) are added in DMF/water (1 : 2, v/v) medium, the receptor RME exhibits a specific "turn-on" colorimetric and fluorometric response. Moreover, RME binding with Cu ions produced a remarkable color variation that was perceptible to the human eye, changing from colorless to pink.
View Article and Find Full Text PDFEcology
January 2025
Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.
Temperate streams are subsidized by inputs of leaf litter peaking in fall. Yet, stream communities decompose dead leaves and integrate their energy into the aquatic food web throughout the whole year. Most studies investigating stream decomposition largely overlook long-term trajectories, which must be understood for an appropriate temporal upscaling of ecosystem processes.
View Article and Find Full Text PDFiScience
January 2025
Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique, Laval, Québec H7V 1B7, Canada.
During infection, dengue virus (DENV) and Zika virus (ZIKV), two (ortho)flaviviruses of public health concern worldwide, induce alterations of mitochondria morphology to favor viral replication, suggesting a viral co-opting of mitochondria functions. Here, we performed an extensive transmission electron microscopy-based quantitative analysis to demonstrate that both DENV and ZIKV alter endoplasmic reticulum-mitochondria contact sites (ERMC). This correlated at the molecular level with an impairment of ERMC tethering protein complexes located at the surface of both organelles.
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