The autofluorescence characteristics of bacterial intracellular and extracellular substances during the operation of anammox reactor

Hou, Xiaolin; Liu, Sitong; Feng, Ying

doi:10.1038/srep39289

Cited by 18 publications

(8 citation statements)

References 27 publications

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“…In the present study, we used the EEM to characterize the fluorescence fingerprints of seven oral microorganisms. Several other researchers have also used an EEM to characterize dissolved organic matter and intra‐/extracellular substances . Although the present study did not analyze the fluorescence spectrum by extracting the intracellular components, various signals appearing in the EEM were attributed to the various biomolecules of the cells based on previous studies .…”

Section: Discussionmentioning

confidence: 75%

Fluorescence fingerprints of oral bacteria

Kang

Jong

Higham

et al. 2019

Journal of Biophotonics

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The rapid detection and identification of microorganisms is one of the most important factors in many cases of ill health. The purpose of this study was to determine the fluorescence characteristics of seven oral bacteria using emission spectra with the aim of distinguishing between the bacteria, and to compare fluorescence imaging methods for the direct assessment of oral bacteria. Fluorescence images of each bacterium were obtained under a 405‐nm light source using a two‐filter system. The emissions of all samples were measured with a fluorescence spectrometer. The complete fluorescence data set collected for each sample employed a three‐dimensional data cube. The differences in the autofluorescence characteristics of the seven oral bacteria were determined by principal components analysis (PCA). The fluorescence images of the oral bacteria varied with the genus and the filter system. The three‐dimensional excitation‐emission matrix fluorescence spectra exhibited distinctive fluorescence features associated with intracellular fluorophores. The seven bacteria could be clearly differentiated on the PCA score plot. The findings of this study indicate that oral bacteria can be identified based on their autofluorescence characteristics. Fluorescence spectroscopy coupled with PCA can be used to detect and classify oral bacteria.

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Section: Discussionmentioning

confidence: 75%

Fluorescence fingerprints of oral bacteria

Kang

Jong

Higham

et al. 2019

Journal of Biophotonics

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“…We acknowledge that there are some limitations in this study. First, although vitamins (e.g., flavin), coenzymes (e.g., NADH), and lipofuscin pigments are suggested to be major sources of cellular autofluorescence (4), we have not analyzed which intracellular molecules characterize the innate fluorescence signatures that distinguish cell types. However, our results demonstrate the effectiveness of innate fluorescence signature analysis as a tool for predicting cell types and physiological status, independent of precise knowledge on how intracellular chemical compositions are mapped onto innate fluorescence signatures.…”

Section: Discussionmentioning

confidence: 99%

“…A cell’s innate fluorescence signature, an assemblage of autofluorescence signals emitted by diverse biomolecules within the cell (1), is known to reflect various cellular properties and physiological statuses. Previous studies have demonstrated that analysis of fluorescence signatures, for example, when coupled with a principal-component analysis (PCA), allows tag-free analysis of cell types and physiological status within live and intact microbial colonies, bulk microbial culture suspensions (2, 3), active sludges (4), mammalian tissues (5, 6), and mammalian cells (1, 7).…”

Section: Introductionmentioning

confidence: 99%

Intra- and Interspecies Variability of Single-Cell Innate Fluorescence Signature of Microbial Cell

Yawata

Kiyokawa

Kawamura

et al. 2019

Appl Environ Microbiol

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Here we analyzed the innate fluorescence signature of the single microbial cell, within both clonal and mixed populations of microorganisms. We found that even very similarly shaped cells differ noticeably in their autofluorescence features and that the innate fluorescence signatures change dynamically with growth phases. We demonstrated that machine learning models can be trained with a data set of single-cell innate fluorescence signatures to annotate cells according to their phenotypes and physiological status, for example, distinguishing a wild-type Aspergillus nidulans cell from its nitrogen metabolism mutant counterpart and log-phase cells from stationary-phase cells of Pseudomonas putida. We developed a minimally invasive method (confocal reflection microscopy-assisted single-cell innate fluorescence [CRIF] analysis) to optically extract and catalog the innate cellular fluorescence signatures of each of the individual live microbial cells in a three-dimensional space. This technique represents a step forward from traditional techniques which analyze the innate fluorescence signatures at the population level and necessitate a clonal culture. Since the fluorescence signature is an innate property of a cell, our technique allows the prediction of the types or physiological status of intact and tag-free single cells, within a cell population distributed in a three-dimensional space. Our study presents a blueprint for a streamlined cell analysis where one can directly assess the potential phenotype of each single cell in a heterogenous population by its autofluorescence signature under a microscope, without cell tagging. IMPORTANCE A cell’s innate fluorescence signature is an assemblage of fluorescence signals emitted by diverse biomolecules within a cell. It is known that the innate fluoresce signature reflects various cellular properties and physiological statuses; thus, they can serve as a rich source of information in cell characterization as well as cell identification. However, conventional techniques focus on the analysis of the innate fluorescence signatures at the population level but not at the single-cell level and thus necessitate a clonal culture. In the present study, we developed a technique to analyze the innate fluorescence signature of a single microbial cell. Using this novel method, we found that even very similarly shaped cells differ noticeably in their autofluorescence features, and the innate fluorescence signature changes dynamically with growth phases. We also demonstrated that the different cell types can be classified accurately within a mixed population under a microscope at the resolution of a single cell, depending solely on the innate fluorescence signature information. We suggest that single-cell autofluoresce signature analysis is a promising tool to directly assess the taxonomic or physiological heterogeneity within a microbial population, without cell tagging.

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“…For example, although the introduction of Cu and OTC slightly reduced the heme c content due to deceleration of AnAOB growth rates, after long-term acclimation to the presence of Cu and OTC, the heme c content of an anammox reactor gradually elevated to 1.2-fold more than the initial content, implying the ability of AnAOB to grow normally under OTC + Cu stress with the help of acclimation (Zhang et al 2016b). Extracellular polymeric substances (EPS) secreted by microorganisms in response to harsh environmental stress chiefly comprised polysaccharides, proteins, humic acids, nucleic acids, and other organic macromolecules (Hou et al 2017), and can affect activated sludge properties (Sheng et al 2010). The characteristics and structures of these biomacromolecules are extremely complex owing to their different functional groups, including hydroxyl, carboxyl, phosphate groups, aldehyde, amide, and benzyl, which are likely to interact with each other and join these macromolecules, resulting in creating more intricate spatial structures (Jia et al 2017).…”

Section: Effect On Heme C and Eps Contentsmentioning

confidence: 99%

A critical review on the effects of antibiotics on anammox process in wastewater

Ozumchelouei

Hamidian

Zhang

et al. 2020

Reviews in Chemical Engineering

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Anaerobic ammonium oxidation (anammox) has recently become of significant interest due to its capability for cost-effective nitrogen elimination from wastewater. However, anaerobic ammonia-oxidizing bacteria (AnAOB) are sensitive to environmental changes and toxic substances. In particular, the presence of antibiotics in wastewater, which is considered unfavorable to the anammox process, has become a growing concern. Therefore, it is necessary to evaluate the effects of these inhibitors to acquire information on the applicability of the anammox process. Hence, this review summarizes our knowledge of the effects of commonly detected antibiotics in water matrices, including fluoroquinolone, macrolide, β-lactam, chloramphenicol, tetracycline, sulfonamide, glycopeptide, and aminoglycoside, on the anammox process. According to the literature, the presence of antibiotics in wastewater could partially or completely inhibit anammox reactions, in which antibiotics targeting protein synthesis or DNA replication (excluding aminoglycoside) were the most effective against the AnAOB strains.

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The autofluorescence characteristics of bacterial intracellular and extracellular substances during the operation of anammox reactor

Cited by 18 publications

References 27 publications

Fluorescence fingerprints of oral bacteria

Fluorescence fingerprints of oral bacteria

Intra- and Interspecies Variability of Single-Cell Innate Fluorescence Signature of Microbial Cell

A critical review on the effects of antibiotics on anammox process in wastewater

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