Extracellular polymeric substances (EPS), which were an important fraction of natural organic matter (NOM), played an important role in various environmental processes. However, the heterogeneity, ...complexity, and dynamics of EPS make their interactions with antibiotics elusive. Using advanced multispectral technology, this study examined how EPS interacts with different concentrations of tetracycline (TC) in the soil system. Our results demonstrated that protein-like (C1), fulvic-like (C2), and humic-like (C3) fractions were identified from EPS. Two-dimensional synchronous correlation spectroscopy (2D–SF–COS) indicated that the protein-like fraction gave faster responses than the fulvic-like fraction during the TC binding process. The sequence of structural changes in EPS due to TC binding was revealed by two-dimensional Fourier Transformation Infrared correlation spectroscopy (2D–FTIR–COS) as follows: 1550 > 1660 > 1395 > 1240 > 1087 cm−1. It is noteworthy that the sensitivity of the amide group to TC has been preserved, with its intensity gradually increasing to become the primary binding site for TC. The integration of hetero-2DCOS maps with moving window 2D correlation spectroscopy (MW2DCOS) provided a unique insight into understanding the correlation between EPS fractions and functional groups during the TC binding process. Moreover, molecular docking (MD) discovered that the extracellular proteins would provide plenty of binding sites with TC through salt bridges, hydrogen bonds, and π-π base-stacking forces. With these results, systematic investigations of the dynamic changes in EPS components under different concentrations of antibiotic exposure demonstrated the advanced capabilities of multispectral technology in examining intricate interactions with EPS in the soil environment.
Display omitted
•Coupling EEM-PARAFAC and 2DCOS provides an interact process new insight.•The amide group gradually became the predominant binding site for TC.•Carboxyl functional groups in EPS were most sensitive to TC binding.•Hydrogen bonding and hydrophobic enhance the affinity between proteins and TC.
•Dynamic interaction mechanism of A. flavus-maize was explored by SWIR-HSI and SR-FTIR.•Spatio-temporal pattern of infected maize with incremental damage for 0–96 h was studied.•Feature extraction ...and quantitative prediction of AFB1 were achieved by SWIR-HSI.•SR-FTIR with 2DCOS reveals nutrient loss and AFB1 biosynthesis in micron-level.•Macro- and micro-scopic chemical imaging techniques verified the dynamic process.
The dynamics mechanisms regulating the growth and AFB1 production of Aspergillus flavus during its interactions with maize kernels remain unclear. In this study, shortwave infrared hyperspectral imaging (SWIR-HSI) and synchrotron radiation Fourier transform infrared (SR-FTIR) microspectroscopy were combined to investigate chemical and spatial–temporal changes in incremental damaged maize kernels induced by A. flavus infection at macroscopic and microscopic levels. SWIR-HSI was employed to extract spectral information of A. flavus growth and quantitatively detect AFB1 levels. Satisfactory full-spectrum models and simplified multispectral models were obtained respectively by partial least squares regression (PLSR) for three types of samples. Furthermore, SR-FTIR microspectroscopy coupled with two-dimensional correlation spectroscopy (2DCOS) was utilized to reveal the possible sequence of dynamic changes of nutrient loss and trace AFB1 in maize kernels. It exhibited new insights on how to quantify the spatio-temporal patterns of fungal infection and AFB1 accumulation on maize and provided theoretical basis for online sorting.
Display omitted
•A fast method of ATR-FTIR had superiority than FT-NIR to discriminate the D. officinale.•The separate effect of different parts is better than harvest times with exploratory ...analysis.•2240 2DCOS images were collected and identified different parts and harvest time.•The relationship between DMA in different parts and harvest times was investigated.
Dendrobium officinale Kimura et Migo, plays an important role in foods, medicinal and health products and its leaves have a high-quality value for raw industrial material. Different parts and harvest time are the main factors causing to differences for its accumulation of active ingredients. This study attempts to evaluate and identify different parts and harvests time of D. officinale multi-platform information combined with chemometrics as a practical strategy. From all the results: (1) Compared with Fourier transform-near infrared spectroscopy (FT-NIR), the models of partial least squares discriminant analysis and support vector machine had absolute advantages to discriminate this plant based on ATR-FTIR; (2) The results of exploratory analysis showed that the samples were gathered well according to different categories, and the recognition effect of different parts is better than that of different harvest time; (3) The synchronous two-dimensional correlation spectrum based on ATR-FTIR can well identify different parts; (4) Compared with the original spectral data, all models were superiority based on Savitzky-Golay, which is more suitable to identify for different parts of D. officinale; (5) The investigation resulted that the best harvest time is from November this year to January next year for stems. The characteristics of this method is a fast, nondestructive, and green method with widely applicability that can not only solve the problem of identification and lay the foundation for further research of medicinal and edible homologous plants, but also provides a theoretical basis for the harvesting time and quality evaluation.
The adsorptive fractionation of humic acid (HA) at the interface between minerals and water can significantly affect the fate of pollutants in water-soil environment. However, the adsorptive ...fractionation behavior of HA on kaolinite and its effect on the migration of fluoroquinolones (FQs) have not been fully understood. In this study, fluorescence and infrared spectroscopy, combined with two-dimensional correlation analyses, were used to explore the adsorptive fractionation of humic acid (HA) and its effects on ofloxacin adsorption on kaolinite. The results indicated that humic-like, rather than reduced quinone-like and tyrosine-like, was the main adsorptive fractionation component and preferentially bound to the Al–O sites of kaolinite. The adsorption mechanisms of humic-like and tyrosine-like mainly include hydrogen bonds between acidic functional groups and the Si–O or Al–O groups of kaolinite, n-π electron donor-acceptor interaction and electrostatic attraction. At pH 7.0, with addition of 4.0 and 16.0 mg C/L HA in solution, the adsorptive fractionation of HA on kaolinite led to increases in ofloxacin (in zwitterionic form) adsorption capacity by 1.46 and 3.35 mg/g, respectively. The interactions between ofloxacin and the humic-like were mainly hydrogen bonds and electrostatic attraction. Therefore, the influence of adsorptive fractionation of dissolved organic matter on minerals should be considered in estimating FQs environmental behaviors.
Display omitted
•Adsorptive fractionation of humic acid (HA) on kaolinite was observed.•Adsorption affinity order was humic-like > tyrosine-like > reduced quinone-like.•Binding of HA with aluminol was stronger than that of siloxane in kaolinite.•HA adsorptive fractionation increased the sorption of ofloxacin on kaolinite.•Ofloxacin primarily adsorbed to sites of humic-like loaded on kaolinite.
3A2g→3T1g(P) transition band of Ni2+ is used to probe the coordination of Ni2+. Two-dimensional asynchronous spectra (2DCOS) are generated using the Double Asynchronous Orthogonal Sample Design ...(DAOSD), Asynchronous Spectrum with Auxiliary Peaks (ASAP) and Two-Trace Two-Dimensional (2T2D) approaches. Cross peaks relevant to the 3A2g→3T1g(P) transition band of Ni2+ are utilized to probe coordination between Ni2+ and various ligands. We studied the spectral behavior of the 3A2g→3T1g(P) transition band when Ni2+ is coordinated with ethylenediaminetetraacetic acid disodium salt (EDTA). The pattern of cross peaks in 2D asynchronous spectrum demonstrates that coordination brings about significant blue shift of the band. In addition, the absorptivity of the band increases remarkably. The interaction between Ni2+ and galactitol is also investigated. Although no clearly observable change is found on the 3A2g→3T1g(P) transition band when galactitol is introduced, the appearance of cross peak in 2D asynchronous spectrum demonstrates that coordination indeed occurs between Ni2+ and galactitol. Furthermore, the pattern of cross peak indicates that peak position, bandwidth and absorptivity of the 3A2g→3T1g(P) transition band of Ni(galactitol)x2+ is considerably different from those of Ni(H2O)62+. Thus, 2DCOS is helpful to reveal subtle spectral variation, which might be helpful in shedding light on the physical-chemical nature of coordination.
Display omitted
•2DCOS with DAOSD and ASAP is used to study coordination between Ni2+ and ligands.•Subtle changes on 3A2g→3T1g(P) band are revealed by cross peaks in 2D spectrum.•Upon coordinating with EDTA, the 3A2g→3T1g(P) band exhibits a blue shift.•Coordination that occurs between Ni2+ and galactitol is confirmed by cross peaks.
Pb0 in flue gas which is ubiquitous in the environment, poses a certain threat to human and ecology, but the study on EPS-dependent stabilization of lead to remove Pb0 from flue gas remains ...insufficient. In this investigation, the characteristics and heavy metals-binding ability of four EPS fractions were evaluated. The EPS were extracted from denitrifying membrane biofilm reactor (MBfR) and divided into slime EPS (S-EPS), loosely-bound EPS (LB-EPS), tightly-bound EPS (TB-EPS) and EPS in circulating flow (Y-EPS). The S, LB, TB-EPS related to Pb stabilization on biofilm need more attention. Compared to Pb-S-EPS (0.013 mg g−1) and Pb-LB-EPS (0.13 mg g−1), the Pb-TB-EPS (0.26 mg g−1) was mainly stable form of vapor Pb0, since TB-EPS's higher content (30.67–82.44 mg g−1 VSS), proteins (13.47–36.32 mg g−1 VSS) and polysaccharides (9.37–32.48 mg g−1 VSS) concentration. Particularly, proteins related ligands were more effective in S, LB, TB-EPS dependent adsorption of Pb, complexing with hydrophobic acid ligands further strengthened in TB-EPS adsorption. The Pb-EPS complex formed via binding with functional groups (such as O–H, N–H, C–H and CC) on EPS, also facilitated by loose structure of proteins. This study enlightens the researchers on the bio-treatment and EPS-dependent biosorption of Pb0 in flue gas in denitrifying MBfR.
Display omitted
•High content and PN concentration of TB-EPS helped the Pb absorption.•TB-EPS played a more important role than S-EPS/LB-EPS in Pb0 flue gas treatment.•The binding ability of EPS was analyzed using EEMs-PARAFAC and 2DCOS.•Aromatic protein, tryptophan, hydrophobic acids ligands of TB-EPS could bind with Pb.•Proteins relevant ligands dominated the Pb adsorption in denitrifying MBfR.
Boletes are favored by consumers because of their unique flavor, rich nutrition and delicious taste. However, the different nutritional values of each species lead to obvious price differences, so ...shoddy products appear on the market, which affects food safety. The aim of this study was to find a rapid and effective method for boletes species identification. In this paper, 1,707 samples of eight boletes species were selected as the research objects. The original Mid-Infrared (MIR) spectroscopy data were adopted for support vector machine (SVM) modeling. The 11,949 spectral images belong to seven data sets such as two-dimensional correlation spectroscopy (2DCOS) and three-dimensional correlation spectroscopy (3DCOS) were used to carry out Alexnet and Residual network (Resnet) modeling, thus we established 15 models for the identification of boletes species. The results show that the SVM method needs to process complex feature data, the time cost is more than 11 times of other models, and the accuracy is not high enough, so it is not recommended to be used in data processing with large sample size. From the perspective of datasets, synchronous 2DCOS and synchronous 3DCOS have the best modeling results, while one-dimensional (1D) MIR Spectrum dataset has the worst modeling results. After comprehensive analysis, the modeling effect of Resnet on the synchronous 2DCOS dataset is the best. Moreover, we use large-screen visualization technology to visually display the sample information of this research and obtain their distribution rules in terms of species and geographical location. This research shows that deep learning combined with 2DCOS and 3DCOS spectral images can effectively and accurately identify boletes species, which provides a reference for the identification of other fields, such as food and Chinese herbal medicine.
Display omitted
•Comprehensive survey on experimental practices in 2D correlation spectroscopy.•Perturbation methods, fields of applications, and types of analytical probes.•Physical phenomena, ...chemical reactions, and biological processes with effects of temperature, concentration, pressure, etc.•Applications, like polymers, proteins, composites, solution mixtures, etc.•Probes, like IR, Raman, NIR, fluorescence, NMR, X-ray, Mass spectrometry, etc.
Noteworthy experimental practices, which are advancing forward the frontiers of the field of two-dimensional (2D) correlation spectroscopy, are reviewed with the focus on various perturbation methods currently practiced to induce spectral changes, pertinent examples of applications in various fields, and types of analytical probes employed. Types of perturbation methods found in the published literature are very diverse, encompassing both dynamic and static effects. Although a sizable portion of publications report the use of dynamic perturbatuions, much greater number of studies employ static effect, especially that of temperature. Fields of applications covered by the literature are also very broad, ranging from fundamental research to practical applications in a number of physical, chemical and biological systems, such as synthetic polymers, composites and biomolecules. Aside from IR spectroscopy, which is the most commonly used tool, many other analytical probes are used in 2D correlation analysis. The ever expanding trend in depth, breadth and versatility of 2D correlation spectroscopy techniques and their broad applications all point to the robust and healthy state of the field.
Display omitted
•3864 1D and 2DCOS images were acquired.•Four deep learning models were established to identify the species of boletes.•Deep learning combined with synchronous 2DCOS has the best ...generalization ability.•Image processing with deep learning was extended to the field of fungi.•Blockchain technology was first applied to the field of microbiology.
Bolete mushrooms are well received by consumers for their rich nutrition and high medicinal value. However, the nutritional value and medicinal value of different species of bolete mushrooms are significantly different. Therefore, it is necessary to identify and trace the species of bolete mushrooms. In this study, Support Vector Machine (SVM) model and four deep learning models with different data sets were established to identify the species of boletes. By comparison, the accuracy of the train set, test set and external verification can reach 100% about the synchronous two-dimensional correlation spectroscopy (2DCOS) model, and the loss value of this model is 0.0257 which is close to zero. Therefore, the synchronous 2DCOS model has the best accuracy and generalization ability. Then, the results of species identification were uploaded to the blockchain platform that we build. Users can query and display the information after identity authentication, so as to realize the traceability of bolete mushrooms. The results show that our method is feasible. The traceability technology based on deep learning and blockchain has been used in the field of microbiology in this research, and it can be extended to other fields.
As an important resource in many prescriptions, the geographical origins of Gentiana rigescens Franch. influences its chemical characteristics, quality and price greatly. Hence, a simple and rapid ...method for the correct classification and identification of the geographical origins of G. rigescens is of significance. In this work, marker components of iridoids were measured by high performance liquid chromatography (HPLC) and were applied as a reference to characterize chemical profiles of samples from different geographical origins. The effects of climate factors on the content differences of G. rigescens were examined by correlation analysis. Afterward, a novel two-dimensional correlation spectroscopy (2DCOS) images acquired based on Fourier transform infrared (FT-IR) spectroscopy was proposed combined to deep learning to identify geographical origins of G. rigescens. Through analyzing the iridoid components of G. rigescens, which discovered that there were significant differences in its five marker components. In addition, the marker components of gentiopicroside based on Northwestern Yunnan (DXB) were higher, and the climate environment of low temperature, temperate, and high precipitation was more suitable for the cultivation and growth of G. rigescens. In the residual convolutional neural network (ResNet), the train set and test set accuracy of synchronous 2DCOS images for the feature bands (1800–400 cm-1) was 100%, and the external validation set of all samples was correctly identified. The results indicated the synchronous 2DCOS images of feature bands were suitable for the correct identification of the geographic origin of G. rigescens, and it reduced the amount of computation and time, and saved computing resources. This study provided a powerful and useful tool for the cultivation and geographical origins identification of G. rigescens.
Display omitted
•The iridoid compounds of G. rigescens were analyzed using HPLC.•The suitable cultivation environment of G. rigescens was analyzed.•ResNet model combined to 2DCOS images for origin identifying of G. rigescens was proposed.•DXB has the highest content of gentiopicroside for G. rigescens.•Synchronous 2DCOS for feature bands has better identification performance.
