The combined effect of selenium (Se) foliar spraying and drought was studied for 3 months in two cultivars of potato; Bard and Adora in Ljubljana, Slovenia. Four combinations of treatments were ...conducted: well-watered plants with and without Se foliar spraying, and drought exposed plants with and without Se foliar spraying. Net photosynthesis, transpiration rate, quantum yield of photosystem II (PSII), and respiration potential measured by electron transport system activity were monitored throughout the period. After three months of treatment, leaf water potential, the number and size of leaf stomata, and tuber yield were determined. Several impacts of drought and Se application and their combinations were established, and the responses shown to be cultivar-specific. Net photosynthesis, transpiration rate, effective quantum yield of PSII, and respiratory potential were lower in drought exposed plants. Se lowered respiratory potential in the leaves in cv. Bard. The mass of the tubers in cv. Adora, and photosynthesis in cvs. Bard and Adora were lower in Se treated plants. Se treatment did not significantly affect the number and size of leaf stomata in the cultivars.
Kombiniran vpliv selena (Se) in suše na dva kultivarja krompirja Bard in Adora, smo preučevali v poskusu, ki je trajal tri mesece. Rastline so bile izpostavljene štirim kombinacijam obravnavanja: zalite rastline z ali brez foliarnega gnojenja s Se in suši izpostavljene rastline z ali brez foliarnega gnojenja s Se. V rastni sezoni smo spremljali neto fotosintezo, transpiracijo, fotokemično učinkovitost fotosistema II (FSII) in respiratorni potenical, merjen s pomočjo meritev aktivnosti terminalnega elektronskega transporta. Po treh mesecih, ko so bile rastline izpostavljene vsem obravnavam, smo izmerili še vodni potencial v listih, število in dimenzije listnih rež in pridelek gomoljev. Preučevana kultivarja sta se na učinke suše in dodanega Se odzvala na različne načine. Neto fotosinteza, transpiracija, fotokemična učinkovitost fotosistema II (FSII) in respiratorni potenical so bili nižji pri rastlinah, ki so bile izpostavljene suši. Rastline, foliarno gnojene s Se so imele nižji respiratorni potencial pri kultivarju Bard. Masa gomoljev pri kultivarju Adora in fotosinteza pri obeh kultivarjih sta bili nižji pri rastlinah, kjer smo dodali Se. Dodatek Se ni bistveno vplival na število in dimenzije listnih rež pri preučevanih kultivarjih.
Effect of selenium (Se) was studied in soybean (Glycine max (L.) Merr.) cv. Olna in Ljubljana, Slovenia. Se was added to plants as foliary spraying. Quantum yield of photosystem II (PSII) and ...respiratory potential measured as ETS activity of mitochondria were measured two times in the growing season. Respiratory potential was higher in young plants compared to mature plants. Se induced the lowering of respiratory potential. Addition of Se had no effect on quantum yield of photosystem II.
Preučevali smo vpliv selena na fiziološke lastnosti soje (Glycine max (L.) Merr.) cv. Olna. Rastline so bile foliarno gnojene s selenom. Meritve fotosintezne učinkovitosti in respiratornega potenciala so bile opravljene dvakrat v rastni sezoni. Respiratorni potencial, merjen s pomočjo aktivnosti terminalnega elektronskega sistema je bil višji pri mladih rastlinah. Respiratorni potencial je bil nižji pri rastlinah, foliarno gnojenih s selenom v primerjavi s kontrolo. Fotosintezna učinkovitost ni bila odvisna od obravnavanja s selenom.
We present deep-learning-enabled super-resolution across different fluorescence microscopy modalities. This data-driven approach does not require numerical modeling of the imaging process or the ...estimation of a point-spread-function, and is based on training a generative adversarial network (GAN) to transform diffraction-limited input images into super-resolved ones. Using this framework, we improve the resolution of wide-field images acquired with low-numerical-aperture objectives, matching the resolution that is acquired using high-numerical-aperture objectives. We also demonstrate cross-modality super-resolution, transforming confocal microscopy images to match the resolution acquired with a stimulated emission depletion (STED) microscope. We further demonstrate that total internal reflection fluorescence (TIRF) microscopy images of subcellular structures within cells and tissues can be transformed to match the results obtained with a TIRF-based structured illumination microscope. The deep network rapidly outputs these super-resolved images, without any iterations or parameter search, and could serve to democratize super-resolution imaging.
Spatial mapping of proteins in tissues is hindered by limitations in multiplexing, sensitivity and throughput. Here we report immunostaining with signal amplification by exchange reaction ...(Immuno-SABER), which achieves highly multiplexed signal amplification via DNA-barcoded antibodies and orthogonal DNA concatemers generated by primer exchange reaction (PER). SABER offers independently programmable signal amplification without in situ enzymatic reactions, and intrinsic scalability to rapidly amplify and visualize a large number of targets when combined with fast exchange cycles of fluorescent imager strands. We demonstrate 5- to 180-fold signal amplification in diverse samples (cultured cells, cryosections, formalin-fixed paraffin-embedded sections and whole-mount tissues), as well as simultaneous signal amplification for ten different proteins using standard equipment and workflows. We also combined SABER with expansion microscopy to enable rapid, multiplexed super-resolution tissue imaging. Immuno-SABER presents an effective and accessible platform for multiplexed and amplified imaging of proteins with high sensitivity and throughput.
Carbon quantum dots (CQDs) obtained from natural organics attract significant attention due to the abundance of carbon sources, varieties of heteroatom doping (such as N, S, P) and good ...biocompatibility of precursor. In this study, tunable fluorescence emission CQDs originated from chlorophyll were synthesized and characterized. The fluorescence emission can be effectively quenched by gold nanoparticles (Au NPs) via fluorescence resonance energy transfer (FRET). Thiocholine, which was produced from acetylthiocholine (ATC) by the hydrolysis of butyrylcholinesterase (BChE), could cause the aggregation of Au NPs and the corresponding recovery of FRET-quenched fluorescence emission. The catalytic activity of BChE could be irreversibly inhibited by organophosphorus pesticides (OPs), thus, the recovery effect was reduced. By evaluating the fluorescence emission intensity of CQDs, a FRET-based sensing platform for OPs determination was established. Paraoxon was studied as an example of OPs. The sensing platform displayed a linear relationship with the logarithm of the paraoxon concentrations in the range of 0.05–50μgL−1 and the limit of detection (LOD) was 0.05μgL−1. Real sample study in tap and river water revealed that this sensing platform was repeatable and accurate. The results indicate that the OP sensor is promising for applications in food safety and environmental monitoring.
•Tunable fluorescence emission of CQDs were synthesized and characterized.•The fluorescence emission of CQDs could be effectively quenched by Au NPs via FRET.•The quenched fluorescence emission of CQDs could be recovered by thiocholine.•A facile FRET-sensing platform for OPs determination was established.
The identification of key foulants and the provision of early warning of high fouling events for drinking water treatment membrane processes is crucial for the development of effective ...countermeasures to membrane fouling, such as pretreatment. Principal foulants include organic, colloidal and particulate matter present in the membrane feed water. In this research, principal component analysis (PCA) of fluorescence excitation-emission matrices (EEMs) was identified as a viable tool for monitoring the performance of pre-treatment stages (in this case biological filtration), as well as ultrafiltration (UF) and nanofiltration (NF) membrane systems. In addition, fluorescence EEM-based principal component (PC) score plots, generated using the fluorescence EEMs obtained after just 1hour of UF or NF operation, could be related to high fouling events likely caused by elevated levels of particulate/colloid-like material in the biofilter effluents. The fluorescence EEM-based PCA approach presented here is sensitive enough to be used at low organic carbon levels and has potential as an early detection method to identify high fouling events, allowing appropriate operational countermeasures to be taken.
Photosynthesis is a pivotal process in plant physiology, and its regulation plays an important role in plant defense against biotic stress. Interactions with pathogens and pests often cause ...alterations in the metabolism of sugars and sink/source relationships. These changes can be part of the plant defense mechanisms to limit nutrient availability to the pathogens. In other cases, these alterations can be the result of pests manipulating the plant metabolism for their own benefit. The effects of biotic stress on plant physiology are typically heterogeneous, both spatially and temporarily. Chlorophyll fluorescence imaging is a powerful tool to mine the activity of photosynthesis at cellular, leaf, and whole-plant scale, allowing the phenotyping of plants. This review will recapitulate the responses of the photosynthetic machinery to biotic stress factors, from pathogens (viruses, bacteria, and fungi) to pests (herbivory) analyzed by chlorophyll fluorescence imaging both at the lab and field scale. Moreover, chlorophyll fluorescence imagers and alternative techniques to indirectly evaluate photosynthetic traits used at field scale are also revised.
The redox states of the NAD and NADP pyridine nucleotide pools play critical roles in defining the activity of energy producing pathways, in driving oxidative stress and in maintaining antioxidant ...defences. Broadly speaking, NAD is primarily engaged in regulating energy-producing catabolic processes, whilst NADP may be involved in both antioxidant defence and free radical generation. Defects in the balance of these pathways are associated with numerous diseases, from diabetes and neurodegenerative disease to heart disease and cancer. As such, a method to assess the abundance and redox state of these separate pools in living tissues would provide invaluable insight into the underlying pathophysiology. Experimentally, the intrinsic fluorescence of the reduced forms of both redox cofactors, NADH and NADPH, has been used for this purpose since the mid-twentieth century. In this review, we outline the modern implementation of these techniques for studying mitochondrial redox state in complex tissue preparations. As the fluorescence spectra of NADH and NADPH are indistinguishable, interpreting the signals resulting from their combined fluorescence, often labelled NAD(P)H, can be complex. We therefore discuss recent studies using fluorescence lifetime imaging microscopy (FLIM) which offer the potential to discriminate between the two separate pools. This technique provides increased metabolic information from cellular autofluorescence in biomedical investigations, offering biochemical insights into the changes in time-resolved NAD(P)H fluorescence signals observed in diseased tissues.
•NAD plays a central role in energy-producing pathways.•NADP is crucial for maintaining the antioxidant defence.•The reduced forms, NADH and NADPH, are naturally fluorescent inside living tissues.•Cellular autofluorescence can be used to investigate NAD(P)H redox state.•NAD(P)H FLIM allows the contributions from NADH and NADPH to be separated.
During multicellular development, specification of distinct cell fates is often regulated by the same transcription factors operating differently in distinct cis-regulatory modules, either through ...different protein complexes, conformational modification of protein complexes, or combinations of both. Direct visualization of different transcription factor complex states guiding specific gene expression programs has been challenging. Here we use in vivo FRET-FLIM (Förster resonance energy transfer measured by fluorescence lifetime microscopy) to reveal spatial partitioning of protein interactions in relation to specification of cell fate. We show that, in Arabidopsis roots, three fully functional fluorescently tagged cell fate regulators establish cell-type-specific interactions at endogenous expression levels and can form higher order complexes. We reveal that cell-type-specific in vivo FRET-FLIM distributions reflect conformational changes of these complexes to differentially regulate target genes and specify distinct cell fates.
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