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result(s) for
"three-dimensional fluorescence"
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Chloroplast-located flavonoids can scavenge singlet oxygen
The hypothesis was tested that flavonoids may scavenge singlet oxygen (¹O₂) in mesophyll cells of Phillyrea latifolia exposed to excess-light stress. In cross-sections taken from leaves developed at 10% (shade) or 100% (sun) solar irradiance, we evaluated the excess photosynthetically active radiation (PAR)-induced accumulation of ¹O₂ in mesophyll cells by imaging the fluorescence quenching of the specific ¹O₂ probe N-[2-(diethylamino)ethyl]-N-[(2,5-dihydro-2,2,5,5-tetramethyl-1H-pyrrol-3-yl)methyl]-5-(dimethylamino)-1-naphthalenesulfonamide (DanePy). The intracellular location of flavonoids was also analyzed using three-dimensional deconvolution microscopy. Photo-induced quenching of DanePy fluorescence was markedly greater in the mesophyll of shade leaves than in that of sun leaves, the former showing a negligible accumulation of mesophyll flavonoids. The photo-induced generation of ¹O₂ was inversely related to the content of flavonoids in the mesophyll cells of sun leaves. Flavonoids were located in the chloroplasts, and were likely associated with the chloroplast envelope. Here we provide relevant evidence for the potential scavenger activity of chloroplast-located flavonoids against ¹O₂ and new insights into the photo-protective role of flavonoids in higher plants.
Journal Article
Agricultural Soil Organic Matters and Microbiome Are Shaped by Management and Hedgerows
Despite the essential roles of soil dissolved organic matter (DOM) and soil microbes in agro-ecosystems, we still have a limited understanding of the extent by which they are impacted by agronomic strategies in ecological and conventional farming. Using three-dimensional fluorescence excitation–emission matrices (3D-EEM) and high-throughput microbial sequencing, the characteristics of soil DOM and microbiota under realistic field conditions were estimated in the farming soils with long-term ecological (EM) and conventional management (CM). Specifically, the role of hedgerows in the ecologically managed land (EMH) was assessed. The total fluorescent intensity of soil DOM in the EMH system was significantly higher than the values in CM and EM systems. Additionally, the five normalized excitation–emission area volumes from regional integration analysis increased in the order CM < EM < EMH. In comparison with CM and EM soils, the hedgerow significantly increased the evenness of the bacterial communities in the EMH system, whereas no differences were found for the alpha-diversity of eukaryotic communities. The composition of soil microbiota was significantly distinct among the three farming systems, with a hedgerow-specific effect on bacterial community and a management-specific effect on eukarya. The predicted functional profiles indicated that the hedgerow showed a higher contribution to the dissimilarity of bacterial functions. Furthermore, the distinction of the soil microbiota was modulated by the soil DOM composition and significantly positive correlations between the microbiota involved in nutrient cycling and soil DOM were observed. The findings in this work strengthen our understanding of the different responses of bacterial and eukaryotic communities under the long-term ecological management and highlight the beneficial roles of hedgerows in increasing organic matter and modulating community assembly.
Journal Article
Common-path multimodal three-dimensional fluorescence and phase imaging system
A stable multimodal system is developed by combining two common-path digital holographic microscopes (DHMs): coherent and incoherent, for simultaneous recording and retrieval of three-dimensional (3-D) phase and 3-D fluorescence imaging (FI), respectively, of a biological specimen. The 3-D FI is realized by a single-shot common-path off-axis fluorescent DHM developed recently by our group. In addition, we accomplish, the phase imaging by another single-shot, highly stable common-path off-axis DHM based on a beam splitter. In this DHM configuration, a beam splitter is used to divide the incoming object beam into two beams. One beam serves as the object beam carrying the useful information of the object under study, whereas another beam is spatially filtered at its Fourier plane by using a pinhole and it serves as a reference beam. This DHM setup, owing to a common-path geometry, is less vibration-sensitive and compact, having a similar field of view but with high temporal phase stability in comparison to a two-beam Mach–Zehnder-type DHM. The performance of the proposed common-path DHM and the multimodal system is verified by conducting various experiments on fluorescent microspheres and fluorescent protein-labeled living cells of the moss Physcomitrella patens. Moreover, the potential capability of the proposed multimodal system for 3-D live fluorescence and phase imaging of the fluorescent beads is also demonstrated. The obtained experimental results corroborate the feasibility of the proposed multimodal system and indicate its potential applications for the analysis of functional and structural behaviors of a biological specimen and enhancement of the understanding of physiological mechanisms and various biological diseases.
Journal Article
Routine Management of Microalgae Using Autofluorescence from Chlorophyll
From a high-potential biomass perspective, microalgae have recently attracted considerable attention due to their extensive application in many areas. Although studies searching for algal species with extensive application potential are ongoing, technical development for their assessment and maintenance of quality in culture are also critical and inescapable challenges. Considering the sensitivity of microalgae to environmental changes, management of algal quality is one of the top priorities for industrial applications. Helping substitute for conventional methods such as manual hemocytometry, turbidity, and spectrophotometry, this review presents an image-based, automated cell counter with a fluorescence filter to measure chlorophyll autofluorescence emitted by algae. Capturing chlorophyll-bearing cells selectively, the device accomplished precise qualification of algal numbers. The results for cell density using the device with fluorescence detection were almost identical to those obtained using hemocytometry. The automated functions of the device allow operators to reduce working hours, for not only cell density analysis but simultaneous multiparametric analysis such as cell size and algal status based on chlorophyll integrity. The automated device boldly supports further development of algal application and might contribute to opening up more avenues in the microalgal industry.
Journal Article
Three-dimensional Fluorescence Spectrum Characteristics and Source Analysis of Dissolved Organic Matter in Sewage Outfall into the Sea of Dongguan
The composition and source analysis of dissolved organic matter (DOM) in sewage outfall into the sea is an effective means of pollutant traceability, which is of great significance to the ecological environment protection in coastal areas. This paper selects Dongguan, an important coastal industrial city in China’s Pearl River, for research. Water samples from 42 sewage outfalls into the sea were measured by three-dimensional fluorescence spectroscopy (3D-EEM). Combined with fluorescence characteristic parameters, similarity analysis and parallel factor analysis (PARAFAC), the spectral characteristics, DOM composition and source were analyzed. The average values of fluorescence parameters fluorescence index (FI), biological index (BIX) and humification index (HIX) were 1.80, 0.94 and 0.55, respectively. The overall PARAFAC analysis found that DOM in the sewage outfall of Dongguan was mainly composed of two fluorescent components, namely tyrosine-like (C1) and humus-like (C2), where tyrosine-like fluorescence was higher than humus-like. This indicates that DOM comes from both terrestrial and endogenous biological activities, but endogenous sources are the primary sources. The similarity analysis divided sewage outfalls into four categories, namely urban rainwater drainage characteristics, typical urban sewage, Jiulong paper-related wastewater and aquaculture water in fish ponds. At the same time, in the PARAFAC analysis, the fluorescence components of 14 urban rainwater outfalls were consistent with the overall analysis results. There are 3 effective parallel factor fluorescence components in 23 outfalls most likely to be contaminated by domestic sewage, namely tyrosine (C1) Humus-like (C2) and tryptophan (C3), C3 components in the characterization of the protein fluorescent tryptophan substance region appeared a strong response peak, belonging to the source pollution, consistent with similarity analysis results. This study suggests that the same source sewage outfalls should be classified management, strengthen the source tracing of sewage outfalls into the sea in neighboring cities, and build a collaborative pollution control system for river basins, estuaries and coastal.
Journal Article
Analysis of the fluorescence spectral characteristics of dissolved organic matter in a black soil with different straw return amounts
Straw return improves soil carbon pool and dissolved organic matter (DOM) characteristics in black soil. Optimal straw return rate is the key to promoting straw return practices in farmland in Northeast China. The experiment was conducted at the Science and Technology Park of China Grain Storage and Northern Corporation in NenJiang, Heilongjiang Province, straw return at 0 kg hm
−2
, 3000 kg hm
−2
, 4500 kg hm
−2
, and 9000 kg hm
−2
. In the seventh year of the experiment, we used three-dimensional excitation-emission matrices combined with Parallel Factor analysis to characterize the fluorescence characteristics of DOM of black soils. The results showed substantial improvement in soil physical characteristics and soil organic matter (SOM) following straw return, SOM content rises in proportion to the amount of straw returned, and a significant positive correlation coefficient between water-holding capacity (WHC) (
p
< 0.001, r = 0.82) and dissolved organic matter (DOC) (
p
< 0.01, r = 0.77). Moreover, straw return significantly increased the richness of three fluorescent components, namely fulvic acid (UV and visible fulvic acids), humic-like acid, and protein-like (short and long-wavelength tryptophan). The fluorescence intensities of these components were lower in straw treatments than in no straw return. The fluorescence intensities of fulvic and humic acids showed decreasing and increasing trends, respectively, with increasing straw return amount. The fluorescence spectroscopy data of DOC demonstrated the key role of high straw return amounts in enhancing substantially the metabolic activity of soil microorganisms. Overall, straw-returning practices improve soil fertility and can be beneficial for black soil farmlands, with the optimal return rate observed at 4500 kg hm
−2
.
Journal Article
Biochemical Oxygen Demand Prediction Based on Three-Dimensional Fluorescence Spectroscopy and Machine Learning
Biochemical oxygen demand (BOD) is an important indicator of the degree of organic pollution in water bodies. Traditional methods for BOD5 determination, although widely used, are complicated and dependent on accurate chemical measurements of dissolved oxygen. The aim of this study was to propose a facile method for predicting biochemical oxygen demand by fluorescence signals using three-dimensional fluorescence spectroscopy and parallel factor analysis in combination with a machine learning algorithm. The water samples were incubated for five days using the national standard method, during which the dissolved oxygen contents and three-dimensional fluorescence spectroscopy data were measured at eight-hour intervals. The maximum fluorescence intensity of three fluorescence components was decomposed and extracted by parallel factor analysis. The relationship between the maximum fluorescence of the three fluorescence components and the BOD5 values was established using a random forest model. The results showed that there was a good correlation between the fluorescence components and BOD values. The BOD5 values were effectively predicted by the random forest model with a high goodness of fit (R2 = 0.878) and low mean square error (MSE = 0.28). Although this method did not shorten the incubation time, successful BOD5 prediction was realized by the non-contact measurement of fluorescence signals. This avoids the complicated operation of DO determination, improves detection efficiency, and provides a convenient solution for analyzing large quantities of water samples and monitoring facile water quality.
Journal Article
Establishing of 3D-FISH on frozen section and its applying in chromosome territories analysis in Populus trichocarpa
Key message
Fluorescence in situ hybridization with frozen sections of root tips showed difference of chromosome territories distribution between autosome and sex-chromosome homologous pairs in
Populus trichocarpa
.
The spatial organization of chromatin within the interphase nucleus and the interactions between chromosome territories (CTs) are essential for various biologic processes. Three-dimensional fluorescence in situ hybridization (3D-FISH) is a powerful tool for analyzing CTs, but its application in plants is limited. In this study, we established a 3D-FISH technique using frozen sections of
Populus trichocarpa
root tips, which was an improvement over the use of paraffin sections and enabled us to acquire good FISH signals. Using chromosome-specific oligo probes, we were able to analyze CTs in interphase nuclei in three dimensions. The distribution of chromosome pairs 17 and 19 in the 3D-preserved nuclei of
P. trichocarpa
root tip cells were analyzed and showed that the autosome pair 17 associated more often than sex chromosome 19. This research lays a foundation for further study of the spatial position of chromosomes in the nucleus and the relationship between gene expression and spatial localization of chromosomes in poplar.
Journal Article
Identification of Oak-Barrel and Stainless Steel Tanks with Oak Chips Aged Wines in Ningxia Based on Three-Dimensional Fluorescence Spectroscopy Combined with Chemometrics
With the increased incidence of wine fraud, a fast and reliable method for wine certification has become a necessary prerequisite for the vigorous development of the global wine industry. In this study, a classification strategy based on three-dimensional fluorescence spectroscopy combined with chemometrics was proposed for oak-barrel and stainless steel tanks with oak chips aged wines. Principal component analysis (PCA), partial least squares analysis (PLS-DA), and Fisher discriminant analysis (FDA) were used to distinguish and evaluate the data matrix of the three-dimensional fluorescence spectra of wines. The results showed that FDA was superior to PCA and PLS-DA in classifying oak-barrel and stainless steel tanks with oak chips aged wines. As a general conclusion, three-dimensional fluorescence spectroscopy can provide valuable fingerprint information for the identification of oak-barrel and stainless steel tanks with oak chips aged wines, while the study will provide some theoretical references and standards for the quality control and quality assessment of oak-barrel aged wines.
Journal Article