Journal of Microbiology

Journal Articles

In Silico Intensive Analysis for the E4 Gene Evolution of Human Adenovirus Species D.: Chanhee Lee, Anyeseu Park, Jeong Yoon Lee; J. Microbiol. 2024;62(5):409-418. Published online April 30, 2024; DOI: https://doi.org/10.1007/s12275-024-00132-1

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Abstract: Adenovirus (Ad) is a ubiquitous pathogen capable of infecting a wide range of animals and humans. Human Adenovirus (HAdV) can cause severe infection, particularly in individuals with compromised immune systems. To date, over 110 types of HAdV have been classified into seven species from A to G, with the majority belonging to the human adenovirus species D (HAdV-D). In the HAdV-D, the most significant factor for the creation of new adenovirus types is homologous recombination between viral genes involved in determining the virus tropism or evading immune system of host cells. The E4 gene, consisting of seven Open Reading Frames (ORFs), plays a role in both the regulation of host cell metabolism and the replication of viral genes. Despite long-term studies, the function of each ORF remains unclear. Based on our updated information, ORF2, ORF3, and ORF4 have been identified as regions with relatively high mutations compared to other ORFs in the E4 gene, through the use of in silico comparative analysis. Additionally, we managed to visualize high mutation sections, previously undetectable at the DNA level, through a powerful amino acid sequence analysis tool known as proteotyping. Our research has revealed the involvement of the E4 gene in the evolution of human adenovirus, and has established accurate sequence information of the E4 gene, laying the groundwork for further research.

Furan-based Chalcone Annihilates the Multi-Drug-Resistant Pseudomonas aeruginosa and Protects Zebra Fish Against its Infection: Santosh Pushpa Ramya Ranjan Nayak , Catharine Basty , Seenivasan Boopathi , Loganathan Sumathi Dhivya , Khaloud Mohammed Alarjani , Mohamed Ragab Abdel Gawwad , Raghda Hager , Muthu Kumaradoss Kathiravan , Jesu Arockiaraj; J. Microbiol. 2024;62(2):75-89. Published online February 21, 2024; DOI: https://doi.org/10.1007/s12275-024-00103-6

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3 Citations

Abstract: The emergence of carbapenem-resistant Pseudomonas aeruginosa, a multi-drug-resistant bacteria, is becoming a serious public health concern. This bacterium infects immunocompromised patients and has a high fatality rate. Both naturally and synthetically produced chalcones are known to have a wide array of biological activities. The antibacterial properties of synthetically produced chalcone were studied against P. aeruginosa. In vitro, study of the compound (chalcone derivative named DKO1), also known as (2E)-1-(5-methylfuran-2-yl)-3-(4-nitrophenyl) prop-2-en-1-one, had substantial antibacterial and biofilm disruptive action. DKO1 effectively shielded against P. aeruginosa-induced inflammation, oxidative stress, lipid peroxidation, and apoptosis in zebrafish larvae. In adult zebrafish, the treatment enhanced the chances of survivability and reduced the sickness-like behaviors. Gene expression, biochemical analysis, and histopathology studies found that proinflammatory cytokines (TNF-α, IL-1β, IL-6, iNOS) were down regulated; antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) levels increased, and histoarchitecture was restored in zebrafish. The data indicate that DKO1 is an effective antibacterial agent against P. aeruginosa demonstrated both in vitro and in vivo.

Reviews

Signification and Application of Mutator and Antimutator Phenotype‑Induced Genetic Variations in Evolutionary Adaptation and Cancer Therapeutics: Woo-Hyun Chung; J. Microbiol. 2023;61(12):1013-1024. Published online December 15, 2023; DOI: https://doi.org/10.1007/s12275-023-00091-z

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Abstract: Mutations present a dichotomy in their implications for cellular processes. They primarily arise from DNA replication errors or damage repair processes induced by environmental challenges. Cumulative mutations underlie genetic variations and drive evolution, yet also contribute to degenerative diseases such as cancer and aging. The mutator phenotype elucidates the heightened mutation rates observed in malignant tumors. Evolutionary adaptation, analogous to bacterial and eukaryotic systems, manifests through mutator phenotypes during changing environmental conditions, highlighting the delicate balance between advantageous mutations and their potentially detrimental consequences. Leveraging the genetic tractability of Saccharomyces cerevisiae offers unique insights into mutator phenotypes and genome instability akin to human cancers. Innovative reporter assays in yeast model organisms enable the detection of diverse genome alterations, aiding a comprehensive analysis of mutator phenotypes. Despite significant advancements, our understanding of the intricate mechanisms governing spontaneous mutation rates and preserving genetic integrity remains incomplete. This review outlines various cellular pathways affecting mutation rates and explores the role of mutator genes and mutation-derived phenotypes, particularly prevalent in malignant tumor cells. An in-depth comprehension of mutator and antimutator activities in yeast and higher eukaryotes holds promise for effective cancer control strategies.

Microbial Interaction is Among the Key Factors for Isolation of Previous Uncultured Microbes: Chang Yan , Jeffrey S. Owen , Eun-Young Seo , Dawoon Jung , Shan He; J. Microbiol. 2023;61(7):655-662. Published online August 17, 2023; DOI: https://doi.org/10.1007/s12275-023-00063-3

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Abstract: Pure cultivation of microbes is still limited by the challenges of microbial uncultivability, with most microbial strains unable to be cultivated under standard laboratory conditions. The experience accumulated from advanced techniques such as in situ cultivation has identified that microbial interactions exist in natural habitats but are absent in laboratory cultures. These microbial interactions are likely one of the key factors in isolating previously uncultured microbes. The need for better knowledge of the mechanisms operating in microbial interactions has led to various experiments that have utilized microbial interactions in different approaches to microbial cultivation. These new attempts to understand microbial interactions not only present a new perspective on microbial uncultivability but also provide an opportunity to access uncultured phylogenetically novel microbes with their potential biotechnology applications. In this review, we focus on studies of the mechanisms of microbial interaction where the growth of other microbes is affected. Additionally, we review some successful applications of microbial interactions in cultivation methods, an approach that can play an important role in the bioprospecting of untapped microbial resources.

Journal Articles

Comparison of Conjunctival Sac Microbiome between Low and High Myopic Eyes: Kang Xiao , Zhengyu Chen , Qin Long; J. Microbiol. 2023;61(5):571-578. Published online April 21, 2023; DOI: https://doi.org/10.1007/s12275-023-00045-5

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Abstract: Microbial communities played a vital role in maintaining homeostasis of ocular surface. However, no studies explored the myopia-associated conjunctiva microbiota changes until now. In this study, conjunctival sac swab specimens were collected from 12 eyes of low myopia (LM), and 14 eyes of high myopia (HM) patients. The V3–V4 region of the 16S rRNA gene was amplified and then sequenced. Statistical analysis was performed to investigate differences in the taxonomy and diversity between two groups. Compared to LM, higher Ocular Surface Disease Index (OSDI) scores were observed in HM group. The Shannon index of the HM was lower than that of the LM group (P = 0.017). Principle coordinate analysis and Partial Least Squares Discrimination Analysis showed distinct microbiome composition between two groups. At the phylum level, there were higher relative abundances of Proteobacteria (68.27% vs 38.51%) and lower abundances of Actinobacteria (3.71% vs 9.19%) in HM, compared to LM group (P = 0.031, 0.010, respectively). At the genus level, the abundances of Acinetobacter in HM (18.16%) were significantly higher than the LM (6.52%) group (P = 0.011). Actinobacteria levels were negatively correlated with the myopic spherical equivalent and OSDI scores. Moreover, positive correlations were found between Proteobacteria levels and OSDI scores, Acinetobacter levels were positively correlated with myopic spherical equivalent and OSDI scores. In conclusion, HM Patients have bacterial microbiota imbalance in the conjunctival sac, compared with LM patients. Proteobacteria, Actinobacteria, Acinetobacter may play roles in the HM associated ocular surface irritation.

Rhizosphere Microbial Community and Metabolites of Susceptible and Resistant Tobacco Cultivars to Bacterial Wilt: Wan Zhao , Yanyan Li , Chunlei Yang , Yong Yang , Yun Hu; J. Microbiol. 2023;61(4):389-402. Published online March 7, 2023; DOI: https://doi.org/10.1007/s12275-023-00012-0

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Abstract: Soil-borne diseases are closely related to rhizosphere microecosystem. While, plant species and genotypes are important factors affected rhizosphere microecosystem. In this study, the rhizosphere soil microbial community and metabolites of susceptible and resistant tobacco cultivars were investigated. The results showed that there were significant differences in the rhizosphere microbial community and metabolites between susceptible cultivar Yunyan87 and resistant cultivar Fandi3. Furthermore, the rhizosphere soil of Fandi3 showed a higher microbial diversity than that of Yunyan87. The abundance of R. solanacearum was much higher in the rhizosphere soil of Yunyan87 than in the rhizosphere soil of Fandi3, resulting in a higher disease incidence and index. While the abundance of beneficial bacteria in the rhizosphere soil of Fandi3 were higher than that of Yunyan87. Additionally, there were significant differences in metabolites between Yunyan87 and Fandi3 cultivars, and 4-hydroxybenzaldehyde, 3-hydroxy-4-methoxybenzoic acid, vamillic aldehyde, benzoic acid, 4-hydroxybenzyl alcohol, p-hydroxybenzoic acid and phthalic acid were notably high in Yunyan87. Redundancy analysis (RDA) indicated that the rhizosphere microbial community of Fandi3 and Yunyan87 were highly correlated with various environmental factors and metabolites. Overall, susceptible and resistant tobacco cultivars had different impact on rhizosphere microbial community and metabolites. The results expand our understanding of the roles of tobacco cultivars in plant-micro-ecosystem interactions, and provide a basis for the control of tobacco bacterial wilt.

The Revision of Lichen Flora Around Maxwell Bay, King George Island, Maritime Antarctic: Jae Eun So , Josef P. Halda , Soon Gyu Hong , Jae&# , Ji Hee Kim; J. Microbiol. 2023;61(2):159-173. Published online February 27, 2023; DOI: https://doi.org/10.1007/s12275-023-00015-x

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Abstract: Since the floristic study of lichens at the Barton and Weaver Peninsulas of King George Island in 2006, there have been intense investigations of the lichen flora of the two peninsulas as well as that of Fildes Peninsula and Ardley Island in Maxwell Bay, King George Island, South Shetland Islands, maritime Antarctic. In this study, a total of 104 species belonging to 53 genera, are identified from investigations of lichens that were collected in austral summer seasons from 2008 to 2016. Phenotypic and molecular analyses were incorporated for taxonomic identification. In particular, 31 species are found to be endemic to the Antarctic and 22 species are newly recorded to the Maxwell Bay region. Lepra dactylina, Stereocaulon caespitosum, and Wahlenbergiella striatula are newly recorded in the Antarctic, and the previously reported taxon Cladonia furcata is excluded from the formerly recorded list due to misidentification. We also provide ecological and geographical information about lichen associations and habitat preferences.

Characterization of Marinilongibacter aquaticus gen. nov., sp. nov., a unique marine bacterium harboring four CRISPR-Cas systems in the phylum Bacteroidota: Dao-Feng Zhang , Yu-Fang Yao , Hua-Peng Xue , Zi-Yue Fu , Xiao-Mei Zhang , Zongze Shao; J. Microbiol. 2022;60(9):905-915. Published online August 1, 2022; DOI: https://doi.org/10.1007/s12275-022-2102-3

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Abstract: A novel bacterium, designated YYF0007T, was isolated from an agar-degrading co-culture. The strain was found harboring four CRISPR-Cas systems of two classes in the chromosome and subsequently subjected to a study on polyphasic taxonomy. Pairwise analyses of the 16S rRNA gene sequences indicated that strain YYF0007T had highest 16S rRNA gene sequence similarity (92.2%) to Jiulongibacter sediminis JN- 14-9T. The phylogenomic trees based on the 16S rRNA gene and 269 single-copy orthologous gene clusters (OCs) indicated that strain YYF0007T should be recognized as a novel genus of the family Spirosomaceae. The cells were Gramstain- negative, nonmotile, strictly aerobic, and straight long rods with no flagellum. Optimum growth occurred at 28°C and pH 7.0 with the presence of NaCl concentration 1.0–3.0% (w/v). The strain showed oxidase and catalase activities. The major fatty acids were C16:1ω5c, iso-C15:0 and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c). The predominant isoprenoid quinone was MK-7. The complete genome size was 4.64 Mb with a DNA G + C content of 44.4%. Further typing of CRISPR-Cas systems in the family Spirosomaceae and the phylum Bacteroidota indicated that it was remarkable for strain YYF0007T featured by such a set of CRISPR-Cas systems. This trait highlights the applications of strain YYF- 0007T in studies on the evolutionary dynamics and bacterial autoimmunity of CRISPR-Cas system as a potential model. The name Marinilongibacter aquaticus gen. nov., sp. nov. is proposed, and the type strain is YYF0007T (= MCCC 1K06017T = GDMCC 1.2428T = JCM 34683T).

Review

[Minireview]The rationale and potential for using Lactobacillus in the management of periodontitis: Jiaqi Wang , Yingman Liu , Weiru Wang , Jiaojiao Ma , Manman Zhang , Xiaoying Lu , Jie Liu , Yurong Kou; J. Microbiol. 2022;60(4):355-363. Published online March 28, 2022; DOI: https://doi.org/10.1007/s12275-022-1514-4

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11 Citations

Abstract: Periodontitis refers to a wide range of the inflammatory conditions of supporting dental structures. For some patients with periodontitis, antibacterial agents are needed as an adjuvant to mechanical debridement treatments and oral hygiene maintenance. However, the widespread use of broad-spectrum antibiotics for the prophylaxis and treatment of periodontal infections
results
in the emergence of resistant pathogens. Therefore, probiotics have become markedly interesting to researchers as a potentially safe alternative to periodontal treatment and maintenance. Probiotics have been used in medicine for decades and extensively applied to the treatment of inflammatory diseases through the modulation of microbial synergy and other mechanisms. A growing amount of evidence has shown that using Lactobacillus strains for oral cavity maintenance could improve periodontal health. In this study, we reviewed studies showing proof of the inhibitory effects of Lactobacillus species on periodontal inflammation. We also explored the rationale and potential for using Lactobacillus species in the management of periodontitis.

Journal Article

The periplasmic chaperone protein Psg_2795 contributes to the virulence of Pseudomonas savastanoi pv. glycinea: the causal agent of bacterial blight of soybean: Xiuhua Wang , Xiaoyan Zhang , Bao-Hui Lu , Jie Gao; J. Microbiol. 2022;60(5):478-487. Published online March 4, 2022; DOI: https://doi.org/10.1007/s12275-022-1469-5

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Abstract: Pseudomonas savastanoi pv. glycinea (Psg, also named P. syringae pv. glycinea and P. amygdali pv. glycinea) is the causative agent of bacterial blight in soybean. The identification of virulence factors is essential for understanding the pathogenesis of Psg. In this study, a mini-Tn5 transposon mutant library of Psg strain PsgNC12 was screened on soybean, and one low-virulent mini-Tn5 mutant, designated as 4573, was identified. Sequence analysis of the 4573-mutant revealed that the mini-Tn5 transposon was inserted in the Psg_2795 gene. Psg_2795 encodes a FimC-domain protein that is highly conserved in Pseudomonas. Further analysis revealed that the mutation and knockout of Psg_2795 results in a reduced virulence phenotype on soybean, decreased motility, weakened bacterial attachment to a glass surface and delayed the population growth within soybean leaves. The phenotype of the 4573-mutant could be complemented nearly to wild-type levels using an intact Psg_2795 gene. Collectively, our results demonstrate that Psg_2795 plays an important role in the virulence, motility, attachment and the population growth of PsgNC12 in soybean. This finding provides a new insight into the function of periplasmic chaperone proteins in a type I pilus and provides reference information for identifying Psg_2795 homologues in P. savastanoi and other bacteria.

Review

Coronavirus enzyme inhibitors-experimentally proven natural compounds from plants: Junsoo Park , Rackhyun Park , Minsu Jang , Yea-In Park , Yeonjeong Park; J. Microbiol. 2022;60(3):347-354. Published online January 28, 2022; DOI: https://doi.org/10.1007/s12275-022-1499-z

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Abstract: Coronavirus disease (COVID-19) can cause critical conditions that require efficient therapeutics. Several medicines are derived from plants, and researchers are seeking natural compounds to ameliorate the symptoms of COVID-19. Viral enzymes are popular targets of antiviral medicines; the genome of coronaviruses encodes several enzymes, including RNAdependent RNA polymerase and viral proteases. Various screening systems have been developed to identify potential inhibitors. In this review, we describe the natural compounds that have been shown to exert inhibitory effects on coronavirus enzymes. Although computer-aided molecular structural studies have predicted several antiviral compound candidates, the current review focuses on experimentally proven natural compounds.

Journal Articles

Effects of rehydration on physiological and transcriptional responses of a water-stressed rhizobium: Jie Zhu , Xin Jiang , Dawei Guan , Yaowei Kang , Li Li , Fengming Cao , Baisuo Zhao , Mingchao Ma , Ji Zhao , Jun Li; J. Microbiol. 2022;60(1):31-46. Published online November 26, 2021; DOI: https://doi.org/10.1007/s12275-022-1325-7

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Abstract: As a microsymbiont of soybean, Bradyrhizobium japonicum plays an important role in symbiotic nitrogen fixation and sustainable agriculture. However, the survival of B. japonicum cells under water-deplete (e.g., drought) and water-replete (e.g., flood) conditions is a major concern affecting their nitrogen-fixing ability by establishing the symbiotic relationship with the host. In this study, we isolated a water stress tolerant rhizobium from soybean root nodules and tested its survival under water-deplete conditions. The rhizobium was identified as Bradyrhizobium japonicum and named strain 5038. Interestingly, both plate counting and live/dead fluorescence staining assays indicate that a number of viable but non-culturable cells exist in the culture medium upon the rehydration process which could cause dilution stress. Bradyrhizobium japonicum 5038 cells increased production of exopolysaccharide (EPS) and trehalose when dehydrated, suggesting that protective responses were stimulated. As expected, cells reduced their production upon the subsequent rehydration. To examine differential gene expression of B. japonicum 5038 when exposed to water-deplete and subsequent waterreplete conditions, whole-genome transcriptional analysis was performed under 10% relative humidity (RH), and subsequent 100% RH, respectively. A total of 462 differentially expressed genes (DEGs, > 2.0-fold) were identified under the 10% RH condition, while 3,776 genes showed differential expression during the subsequent rehydration (100% RH) process. Genes involved in signal transduction, inorganic ion transport, energy production and metabolisms of carbohydrates, amino acids, and lipids were far more up-regulated than downregulated in the 10% RH condition. Notably, trehalose biosynthetic genes (otsAB, treS, and treYZ), genes ligD, oprB, and a sigma factor rpoH were significantly induced by 10% RH. Under the subsequent 100% RH condition, genes involved in transcription, translation, cell membrane regulation, replication and repair, and protein processing were highly up-regulated. Interestingly, most of 10%-RH inducible genes displayed rehydration-repressed, except three genes encoding heat shock (Hsp20) proteins. Therefore, this study provides molecular evidence for the switch of gene expression of B. japonicum cells when encountered the opposite water availability from water-deplete to water-replete conditions.

The type II histidine triad protein HtpsC facilitates invasion of epithelial cells by highly virulent Streptococcus suis serotype 2: Yunjun Lu , Shu Li , Xiaodong Shen , Yan Zhao , Dongming Zhou , Dan Hu , Xushen Cai , Lixia Lu , Xiaohui Xiong , Ming Li , Min Cao; J. Microbiol. 2021;59(10):949-957. Published online September 7, 2021; DOI: https://doi.org/10.1007/s12275-021-1129-1

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Abstract: Streptococcus suis serotype 2 (S. suis 2) is an important zoonotic pathogen that presents a significant threat both to pigs and to workers in the pork industry. The initial steps of S. suis 2 pathogenesis are unclear. In this study, we found that the type II histidine triad protein HtpsC from the highly virulent Chinese isolate 05ZYH33 is structurally similar to internalin A (InlA) from Listeria monocytogenes, which plays an important role in mediating listerial invasion of epithelial cells. To determine if HtpsC and InlA function similarly, an isogenic htpsC mutant (ΔhtpsC) was generated in S. suis by homologous recombination. The htpsC deletion strain exhibited a diminished ability to adhere to and invade epithelial cells from different sources. Double immunofluorescence microscopy also revealed reduced survival of the ΔhtpsC mutant after cocultivation with epithelium. Adhesion to epithelium and invasion by the wild type strain was inhibited by a monoclonal antibody against E-cadherin. In contrast, the htpsC-deficient mutant was unaffected by the same treatment, suggesting that E-cadherin is the host-cell receptor that interacts with HtpsC and facilitates bacterial internalization. Based on these results, we propose that HtpsC is involved in the process by which S. suis 2 penetrates host epithelial cells, and that this protein is an important virulence factor associated with cell adhesion and invasion.

The putative sensor histidine kinase VadJ coordinates development and sterigmatocystin production in Aspergillus nidulans: Yanxia Zhao , Mi-Kyung Lee , Jieyin Lim , Heungyun Moon , Hee-Soo Park , Weifa Zheng , Jae-Hyuk Yu; J. Microbiol. 2021;59(8):746-752. Published online July 5, 2021; DOI: https://doi.org/10.1007/s12275-021-1055-2

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6 Citations

Abstract: The VosA-VelB heterocomplex governs expression of several genes associated with fungal development and secondary metabolism. In this study, we have investigated the functions of one of the VosA-VelB-activated developmental genes vadJ in development and production of the mycotoxin sterigmatocystin in the model fungus Aspergillus nidulans. The vadJ gene is predicted to encode a 957-amino acid length protein containing a highly conserved sensor histidine kinase domain. The deletion of vosA or velB resulted in decreased mRNA levels of vadJ throughout the life cycle, suggesting that VosA and VelB are necessary for proper expression of vadJ. Nullifying vadJ led to highly restricted colony growth, lowered formation of asexual spores, and about two-fold reduction in conidial viability. Conversely, the deletion of vadJ resulted in elevated production of sexual fruiting bodies and sterigmatocystin. These suggest that VadJ is necessary for proper coordination of asexual and sexual development, and sterigmatocystin production. In accordance with this idea, the deletion of vadJ led to elevated mRNA levels of the two key sexual developmental activators esdC and nsdD. In summary, the putative sensor histidine kinase VadJ represses sexual development and sterigmatocystin production, but activates asexual development in A. nidulans.

Review

Microbial phenomics linking the phenotype to function: The potential of Raman spectroscopy: Jin-Kyung Hong , Soo Bin Kim , Eun Sun Lyou , Tae Kwon Lee; J. Microbiol. 2021;59(3):249-258. Published online January 26, 2021; DOI: https://doi.org/10.1007/s12275-021-0590-1

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20 Citations

Abstract: Raman spectroscopy is a promising tool for identifying microbial phenotypes based on single cell Raman spectra reflecting cellular biochemical biomolecules. Recent studies using Raman spectroscopy have mainly analyzed phenotypic changes caused by microbial interactions or stress responses (e.g., antibiotics) and evaluated the microbial activity or substrate specificity under a given experimental condition using stable isotopes. Lack of labelling and the nondestructive pretreatment and measurement process of Raman spectroscopy have also aided in the sorting of microbial cells with interesting phenotypes for subsequently conducting physiology experiments through cultivation or genome analysis. In this review, we provide an overview of the principles, advantages, and status of utilization of Raman spectroscopy for studies linking microbial phenotypes and functions. We expect Raman spectroscopy to become a next-generation phenotyping tool that will greatly contribute in enhancing our understanding of microbial functions in natural and engineered systems.

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