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Single-Molecule Imaging of mRNA Localization and Regulation during the Integrated Stress Response
摘要： Biological phase transitions form membrane-less organelles that generate distinct cellular environments. How molecules are partitioned between these compartments and the surrounding cellular space and the functional consequence of this localization is not well understood. Here, we report the localization of mRNA to stress granules (SGs) and processing bodies (PBs) and its effect on translation and degradation during the integrated stress response. Using single mRNA imaging in living human cells, we find that the interactions of mRNAs with SGs and PBs have different dynamics, very few mRNAs directly move between SGs and PBs, and that specific RNA-binding proteins can anchor mRNAs within these compartments. During recovery from stress, we show that mRNAs that were within SGs and PBs are translated and degraded at similar rates as their cytosolic counterparts. Our work provides a framework for using single-molecule measurements to directly investigate the molecular mechanisms of phase-separated compartments within their cellular environment.
关键词： P-bodies,integrated stress response,degradation,stress granules,LARP1,mRNA localization,single-molecule imaging,translation
更新于2025-09-23 15:22:29
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Retrieval of Chlorophyll a from Sentinel-2 MSI Data for the European Union Water Framework Directive Reporting Purposes
摘要： The European Parliament and The Council of the European Union have established the Water Framework Directive (2000/60/EC) for all European Union member states to achieve, at least, 'good' ecological status of all water bodies larger than 50 hectares in Europe. The MultiSpectral Instrument onboard European Space Agency satellite Sentinel-2 has suitable 10, 20, 60 m spatial resolution to monitor most of the Estonian lakes as required by the Water Framework Directive. The study aims to analyze the suitability of Sentinel-2 MultiSpectral Instrument data to monitor water quality in inland waters. This consists of testing various atmospheric correction processors to remove the influence of atmosphere and comparing and developing chlorophyll a algorithms to estimate the ecological status of water in Estonian lakes. This study shows that the Sentinel-2 MultiSpectral Instrument is suitable for estimating chlorophyll a in water bodies and tracking the spatial and temporal dynamics in the lakes. However, atmospheric corrections are sensitive to surrounding land and often fail in narrow and small lakes. Due to that, deriving satellite-based chlorophyll a is not possible in every case, but initial results show the Sentinel-2 MultiSpectral Instrument could still provide complementary information to in situ data to support Water Framework Directive monitoring requirements.
关键词： atmospheric correction,chlorophyll a,optically complex waters,remote sensing,European Union Water Framework Directive (2000/60/EC),ecological status of water bodies,Copernicus,Sentinel-2 MultiSpectral Instrument
更新于2025-09-23 15:22:29
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Visualizing pore architecture and molecular transport boundaries in catalyst bodies with fluorescent nanoprobes
摘要： The performances of porous materials are closely related to the accessibility and interconnectivity of their porous domains. Visualizing pore architecture and its role on functionality—for example, mass transport—has been a challenge so far, and traditional bulk and often non-visual pore measurements have to suffice in most cases. Here, we present an integrated, facile fluorescence microscopy approach to visualize the pore accessibility and interconnectivity of industrial-grade catalyst bodies, and link it unequivocally with their catalytic performance. Fluorescent nanoprobes of various sizes were imaged and correlated with the molecular transport of fluorescent molecules formed during a separate catalytic reaction. A direct visual relationship between the pore architecture—which depends on the pore sizes and interconnectivity of the material selected—and molecular transport was established. This approach can be applied to other porous materials, and the insight gained may prove useful in the design of more efficient heterogeneous catalysts.
关键词： porous materials,molecular transport,fluorescence microscopy,catalyst bodies,heterogeneous catalysts
更新于2025-09-23 15:21:01
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Lipid Droplet Composition Varies Based on Medaka Fish Eggs Development as Revealed by NIR-, MIR-, and Raman Imaging
摘要： In fertilized fish eggs, lipids are an energy reservoir for the embryo development and substrate for organogenesis. They occur in the cytoplasmic area and form lipid droplets (LDs), but also the yolk egg is composed of lipids and proteins. Insight on the LD formation and distribution and their interactions with other cellular organelles could provide information about the role based on the egg development. For non-destructive, macro-scale visualization of biochemical components of fish eggs, such as lipids proteins and water, near-infrared (NIR) imaging is the method of choice. Mid-infrared (MIR) and Raman spectroscopy imaging were used to provide details on chemical composition of LDs and other egg organelles. NIR imaging illustrated main compartments of the egg including membrane, LDs, yolk, relative protein, and lipid content in well-localized egg structures and their interactions with water molecules. In the yolk, a co-existence of lipids and proteins with carotenoids and carbohydrates was detected by Raman spectroscopy. Results showed a prominent decrease of unsaturated fatty acids, phospholipids, and triglycerides/cholesteryl esters content in the eggs due to the embryo development. An opposite trend of changes was observed by MIR spectroscopy for the glycogen, suggesting that consumption of lipids occurred with production of this carbohydrate. The comprehensive vibrational spectroscopic analysis based on NIR, MIR, and Raman imaging is a unique tool in studying in situ dynamic biological processes.
关键词： near- and mid-infrared spectroscopic imaging,Raman spectroscopic imaging,lipids,lipid bodies,fertilized egg
更新于2025-09-16 10:30:52
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Experimental characterization of the performance of different photovoltaic technologies on water bodies
摘要： Long term performance analysis of different PV technologies under the climatic condition of water bodies helps in the selection of appropriate PV technology for the large scale deployment on water bodies. The objective of the present research is to evaluate the suitability of different PV technologies on water bodies using performance and degradation analysis. Therefore, an experimental setup was designed to analyze the performance and degradation of HIT, Poly‐Si and CdTe PV technologies on the water surface and to compare their performance and degradation with the respective PV technologies deployed on the land surface. The data from experimental setup was measured for over one year duration. Furthermore, the evaporation reduction in PV panels covered water bodies has been experimentally measured. The performance of HIT and Poly‐Si PV panels on the water surface are found to be 0.4% and 2.7% lower than the corresponding land based panels, respectively; whereas the performance of CdTe panel on the water surface is found to be 3.1% higher than corresponding land based panel. The Poly‐Si panel has a degradation of 1.32% on the water surface which is significantly higher than the degradation rate of 0.93% of the corresponding land‐based panel whereas the HIT panels have almost similar degradation of approximately 0.50% in both climatic conditions. Thus, the study concludes that the HIT and CdTe technologies are suitable for water bodies applications. The experimental results show that the PV panel cover on the water bodies has reduced the evaporation loss by about 29% in one year.
关键词： PV technologies,performance analysis,degradation,water bodies based PV systems
更新于2025-09-12 10:27:22
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Investigation on Perceptron Learning for Water Region Estimation Using Large-Scale Multispectral Images
摘要： Land cover classification and investigation of temporal changes are considered to be common applications of remote sensing. Water/non-water region estimation is one of the most fundamental classification tasks, analyzing the occurrence of water on the Earth’s surface. However, common remote sensing practices such as thresholding, spectral analysis, and statistical approaches are not sufficient to produce a globally adaptable water classification. The aim of this study is to develop a formula with automatically derived tuning parameters using perceptron neural networks for water/non-water region estimation, which we call the Perceptron-Derived Water Formula (PDWF), using Landsat-8 images. Water/non-water region estimates derived from PDWF were compared with three different approaches—Modified Normalized Difference Water Index (MNDWI), Automatic Water Extraction Index (AWEI), and Deep Convolutional Neural Network—using various case studies. Our proposed method outperforms all three approaches, showing a significant improvement in water/non-water region estimation. PDWF performance is consistently better even in cases of challenging conditions such as low reflectance due to hill shadows, building-shadows, and dark soils. Moreover, our study implemented a sunglint correction to adapt water/non-water region estimation over sunglint-affected pixels.
关键词： surface water bodies,Landsat-8,MNDWI,deep neural network,perceptron neural network,AWEI,PDWF
更新于2025-09-04 15:30:14