Journal of Microbiology

The most downloaded articles in the last three months among those published since 2023.

Journal Articles

Thalassotalea aquiviva sp. nov., and Thalassotalea maritima sp. nov., Isolated from Seawater of the Coast in South Korea: Jina Lee, Seung-Hui Song, Kira Moon, Nakyeong Lee, Sangdon Ryu, Hye Seon Song, Sung Moon Lee, Yun Ji Kim, Se Won Chun, Kyung-Min Choi, Aslan Hwanhwi Lee; J. Microbiol. 2024;62(12):1099-1111. Published online December 10, 2024; DOI: https://doi.org/10.1007/s12275-024-00191-4

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Abstract: Two novel bacterial strains, 273M-4^T and Sam97^T, were isolated from seawater in the Yellow Sea, Muan-gun, South Korea, and identified as members of the genus Thalassotalea. Both strains were Gram-stain-negative, aerobic, rod-shaped, non-motile, non-flagellated, and oxidase- and catalase-positive. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains 273M-4^T and Sam97^T were most closely related to Thalassotalea ponticola KCTC 42155^T, with sequence similarities of 97.5% and 98.3%, respectively. Optimal growth for strain 273M-4^T occurred at 25-30 °C, pH 7.0, and 2% NaCl, while strain Sam97^T grew optimally at 30 °C, pH 8.0, and 2% NaCl. Genome sizes of strains 273M-4^T and Sam97^T were 3.37 and 3.31 Mb, with DNA G + C contents of 41.0 mol% and 42.9 mol%, respectively. The orthologous average nucleotide identity (OrthoANI) and digital DNA-DNA hybridization (dDDH) values between the two strains were 71.6% and 24.4%, respectively, indicating that they are distinct species. Further genomic analyses of these two strains revealed OrthoANI values of < 73.5% and dDDH values of < 26.7% within the genus Thalassotalea, suggesting their distinctiveness from other Thalassotalea species. The predominate fatty acids of strains 273M-4^T and Sam97^T were summed feature 3 (consisting of C_16:1 ω7c/C_16:1 ω6c) and C_16:0. All strains contained phosphatidylethanolamine and phosphatidylglycerol as the major polar lipids and ubiquinone-8 (Q-8) as the primary respiratory quinone. Based on phenotypic, phylogenetic, genotypic, and chemotaxonomic data, strains 273M-4^T (= KCTC 8644^T = LMG 33695^T) and Sam97^T (= KCTC 8645^T = LMG 33694^T) represent novel species of the genus Thalassotalea, named Thalassotalea aquiviva sp. nov. and Thalassotalea maritima sp. nov..

Characterization of Newly Isolated Bacteriophages Targeting Carbapenem-Resistant Klebsiella pneumoniae: Bokyung Kim, Shukho Kim, Yoon-Jung Choi, Minsang Shin, Jungmin Kim; J. Microbiol. 2024;62(12):1133-1153. Published online December 10, 2024; DOI: https://doi.org/10.1007/s12275-024-00180-7

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Abstract: Klebsiella pneumoniae, a Gram-negative opportunistic pathogen, is increasingly resistant to carbapenems in clinical settings. This growing problem necessitates the development of alternative antibiotics, with phage therapy being one promising option. In this study, we investigated novel phages targeting carbapenem-resistant Klebsiella pneumoniae (CRKP) and evaluated their lytic capacity against clinical isolates of CRKP. First, 23 CRKP clinical isolates were characterized using Multi-Locus Sequence Typing (MLST), carbapenemase test, string test, and capsule typing. MLST classified the 23 K. pneumoniae isolates into 10 sequence types (STs), with the capsule types divided into nine known and one unknown type. From sewage samples collected from a tertiary hospital, 38 phages were isolated. Phenotypic and genotypic characterization of these phages was performed using Random Amplification of Polymorphic DNA-PCR (RAPD-PCR), transmission electron microscopy (TEM), and whole genome sequencing (WGS) analysis. Host spectrum analysis revealed that each phage selectively lysed strains sharing the same STs as their hosts, indicating ST-specific activity. These phages were subtyped based on their host spectrum and RAPD-PCR, identifying nine and five groups, respectively. Fourteen phages were selected for further analysis using TEM and WGS, revealing 13 Myoviruses and one Podovirus. Genomic analysis grouped the phages into three clusters: one closely related to Alcyoneusvirus, one to Autographiviridae, and others to Straboviridae. Our results showed that the host spectrum of K. pneumoniae-specific phages corresponds to the STs of the host strain. These 14 novel phages also hold promise as valuable resources for phage therapy against CRKP.

CalR Inhibits the Swimming Motility and Polar Flagellar Gene Expression in Vibrio parahaemolyticus: Jingyang Chang, Yining Zhou, Miaomiao Zhang, Xue Li, Nan Zhang, Xi Luo, Bin Ni, Haisheng Wu, Renfei Lu, Yiquan Zhang; J. Microbiol. 2024;62(12):1125-1132. Published online December 6, 2024; DOI: https://doi.org/10.1007/s12275-024-00179-0

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Abstract: Vibrio parahaemolyticus has two flagellar systems, the polar flagellum and lateral flagella, which are both intricately regulated by a multitude of factors. CalR, a LysR-type transcriptional regulator, is sensitive to calcium (Ca) and plays a crucial role in regulating the virulence and swarming motility of V. parahaemolyticus. In this study, we have demonstrated that the deletion of calR significantly enhances the swimming motility of V. parahaemolyticus under low Ca conditions but not under high Ca conditions or in the absence of Ca. CalR binds to the regulatory DNA regions of flgM, flgA, and flgB, which are located within the polar flagellar gene loci, with the purpose of repressing their transcription. Additionally, it exerts an indirect negative control over the transcription of flgK. The overexpression of CalR in Escherichia coli resulted in a reduction in the expression levels of flgM, flgA, and flgB, while having no impact on the expression of flgK. In summary, this research demonstrates that the negative regulation of V. parahaemolyticus swimming motility by CalR under low Ca conditions is achieved through its regulation on the transcription of polar flagellar genes.

Gut Microbiota Dysbiosis Facilitates Susceptibility to Bloodstream Infection: Xiaomin Lin, Chun Lin, Xin Li, Fen Yao, Xiaoling Guo, Meimei Wang, Mi Zeng, Yumeng Yuan, Qingdong Xie, Xudong Huang, Xiaoyang Jiao; J. Microbiol. 2024;62(12):1113-1124. Published online December 2, 2024; DOI: https://doi.org/10.1007/s12275-024-00190-5

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Abstract: To study the role of intestinal flora in the development of bloodstream infections (BSIs). 42 patients and 19 healthy controls (HCs) were screened into the study and their intestinal flora was measured by 16S rRNA gene sequencing. The bacterial diversity was significantly lower in the BSI group compared with that in the HCs (P < 0.001), and beta diversity was significantly differentiated between the two groups (PERMANOVA, P = 0.001). The four keystone species [Roseburia, Faecalibacterium, Prevotella, and Enterococcus (LDA > 4)] differed significantly between the two groups. Dysbiosis of fecal microbial ecology is a common condition present in patients with BSI. The proliferation of certain pathogens or reduction of SCFA-producing bacteria would cause susceptibility to BSI.

Leuconostoc aquikimchii sp. nov., a Lactic Acid Bacterium Isolated from Cabbage Watery Kimchi: Subin Kim, Se Hee Lee, Ki Hyun Kim, Misun Yun; J. Microbiol. 2024;62(12):1089-1097. Published online December 2, 2024; DOI: https://doi.org/10.1007/s12275-024-00188-z

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Abstract: Two Gram-stain-positive, facultatively anaerobic, non-hemolytic, coccoid-shaped bacterial strains, designated MS01(T) and MS02, were isolated from cabbage watery kimchi in the Republic of Korea. Cellular growth occurred at 5-25 ℃ (optimum, 20 ℃), pH 5-8 (optimum, pH 7) and in the presence of 0-5% (w/v) NaCl (optimum, 1%). Results of 16S rRNA gene-based phylogenetic analyses showed that strains MS01(T) and MS02 shared identical sequences, clustered within the Leuconostoc clade in phylogenetic trees, and were most closely related to Leuconostoc inhae IH003(T) and Leuconostoc gasicomitatum LMG 18811(T) with sequence similarities of 98.74%. The complete whole-genome sequences of strains MS01(T) and MS02 measured 2.04-2.06 Mbp and harbored a 50.6 kb plasmid, with DNA G + C contents of 37.7% for both. Based on average nucleotide identities (ANI) and digital DNA-DNA hybridization (dDDH) values, both strains were confirmed to belong to the same species but showed ≤ 85.9% ANI and ≤ 29.9% dDDH values to other Leuconostoc species, indicating that they represent a novel species. Metabolic pathway reconstruction revealed that both strains perform heterolactic acid fermentation, producing lactate, acetate, and ethanol. Chemotaxonomic analyses, including cellular fatty acids, polar lipids, and peptidoglycan amino acid, confirmed the inclusion of both strains within the genus Leuconostoc. Based on the phylogenetic, genomic, and phenotypic characterization, strains MS01(T) and MS02 were considered to represent a novel species within the genus Leuconostoc, for which the name Leuconostoc aquikimchii sp. nov. is proposed with MS01(T) (= KACC 23748(T) = JCM 37028(T)) as the type strain.

Comparative Secretory Efficiency of Two Chitosanase Signal Peptides from Bacillus subtilis in Escherichia coli: Tae-Yang Eom, Yehui Gang, Youngdeuk Lee, Yoon-Hyeok Kang, Eunyoung Jo, Svini Dileepa Marasinghe, Heung Sik Park, Gun-Hoo Park, Chulhong Oh; J. Microbiol. 2024;62(12):1155-1164. Published online November 25, 2024; DOI: https://doi.org/10.1007/s12275-024-00186-1

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Abstract: The production of recombinant proteins in Escherichia coli is often challenged by cytoplasmic expression due to proteolytic degradation and inclusion body formation. Extracellular expression can overcome these problems by simplifying downstream processing and improving protein yields. This study aims to compare the efficiency of two Bacillus subtilis chitosanase signal peptides in mediating extracellular secretion in E. coli. We identified a naturally occurring mutant signal peptide (mCsn2-SP) from B. subtilis CH2 chitosanase (CH2CSN), which is characterized by a deletion of six amino acids in the N-region relative to the signal peptide (Csn1-SP) from B. subtilis CH1 chitosanase (CH1CSN). The CH1CSN and CH2CSN genes were cloned into the pET-11a vector and protein secretion was evaluated in E. coli BL21(DE3) host cells. Expression was induced with 0.1 mM and 1 mM isopropyl β-D-1-thiogalactopyranoside (IPTG) at 30 °C for one and three days. CH2CSN showed higher secretion levels compared to CH1CSN under all experimental conditions, especially with 0.1 mM IPTG induction for 3 days, which resulted in a 2.37-fold increase in secretion. Furthermore, it was demonstrated that mCsn2-SP is capable of secreting human Cu,Zn-superoxide dismutase (hSOD) in E. coli BL21(DE3) and successfully translocating it to the periplasmic region. This study represents the inaugural investigation into the utilisation of a naturally modified signal peptide, thereby corroborating the assertion that signal peptide deletion variants can influence protein secretion efficiency. Furthermore, the findings substantiate the proposition that such variants can serve as a viable alternative for the secretion of heterologous proteins in E. coli.

Characterization and Comparative Genomic Analysis of vB_BceM_CEP1: A Novel Temperate Bacteriophage Infecting Burkholderia cepacia Complex: Momen Askoura, Eslam K Fahmy, Safya E Esmaeel, Wael A H Hegazy, Aliaa Abdelghafar; J. Microbiol. 2024;62(11):1035-1055. Published online November 18, 2024; DOI: https://doi.org/10.1007/s12275-024-00185-2

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Abstract: The increasing prevalence of multidrug-resistant bacteria imminently threatens public health and jeopardizes nearly all aspects of modern medicine. The Burkholderia cepacia complex (Bcc) comprises Burkholderia cepacia and the related species of Gram-negative bacteria. Members of the Bcc group are opportunistic pathogens responsible for various chronic illnesses, including cystic fibrosis and chronic granulomatous disease. Phage therapy is emerging as a potential solution to combat the antimicrobial resistance crisis. In this study, a temperate phage vB_BceM_CEP1 was isolated from sewage and fully characterized. Transmission electron microscopy indicated that vB_BceM_CEP1 belongs to the family Peduoviridae. The isolated phage demonstrated enhanced environmental stability and antibiofilm potential. One-step growth analysis revealed a latent period of 30 min and an average burst size of 139 plaque-forming units per cell. The genome of vB_BceM_CEP1 consists of 32,486 bp with a GC content of 62.05%. A total of 40 open reading frames were annotated in the phage genome, and none of the predicted genes was annotated as tRNA. Notably, genes associated with antibiotic resistance, host virulence factors, and toxins were absent from the vB_BceM_CEP1 genome. Based on its unique phenotype and phylogeny, the isolated phage vB_BceM_CEP1 is classified as a new temperate phage with lytic activity. The findings of this study enhance our understanding of the diversity of Bcc phages.

Review

Fecal Microbiota Transplantation: Indications, Methods, and Challenges.: Jee Young Lee, Yehwon Kim, Jiyoun Kim, Jiyeun Kate Kim; J. Microbiol. 2024;62(12):1057-1074. Published online November 18, 2024; DOI: https://doi.org/10.1007/s12275-024-00184-3

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Abstract: Over the past two decades, as the importance of gut microbiota to human health has become widely known, attempts have been made to treat diseases by correcting dysbiosis of gut microbiota through fecal microbiota transplantation (FMT). Apart from current knowledge of gut microbiota, FMT to treat disease has a long history, from the treatment of food poisoning in the fourth century to the treatment of Clostridioides difficile infections in the twentieth century. In 2013, FMT was recognized as a standard treatment for recurrent C. difficile because it consistently showed high efficacy. Though recurrent C. difficile is the only disease internationally recognized for FMT efficacy, FMT has been tested for other diseases and shown some promising preliminary results. Different FMT methods have been developed using various formulations and administration routes. Despite advances in FMT, some issues remain to be resolved, such as donor screening, manufacturing protocols, and unknown components in the fecal microbiota. In this review, we discuss the mechanisms, clinical indications, methods, and challenges of current FMT. We also discuss the development of alternative therapies to overcome the challenges of FMT.

Journal Articles

Rhodobacteraceae are Prevalent and Ecologically Crucial Bacterial Members in Marine Biofloc Aquaculture: Meora Rajeev, Jang-Cheon Cho; J. Microbiol. 2024;62(11):985-997. Published online November 15, 2024; DOI: https://doi.org/10.1007/s12275-024-00187-0

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Abstract: Bioflocs are microbial aggregates primarily composed of heterotrophic bacteria that play essential ecological roles in maintaining animal health, gut microbiota, and water quality in biofloc aquaculture systems. Despite the global adoption of biofloc aquaculture for shrimp and fish cultivation, our understanding of biofloc microbiota-particularly the dominant bacterial members and their ecological functions-remains limited. In this study, we employed integrated metataxonomic and metagenomic approaches to demonstrate that the family Rhodobacteraceae of Alphaproteobacteria consistently dominates the biofloc microbiota and plays essential ecological roles. We first analyzed a comprehensive metataxonomic dataset consisting of 200 16S rRNA gene amplicons collected across three Asian countries: South Korea, China, and Vietnam. Taxonomic investigation identified Rhodobacteraceae as the dominant and consistent bacterial members across the datasets. The predominance of this taxon was further validated through metagenomics approaches, including read taxonomy and read recruitment analyses. To explore the ecological roles of Rhodobacteraceae, we applied genome-centric metagenomics, reconstructing 45 metagenome-assembled genomes. Functional annotation of these genomes revealed that dominant Rhodobacteraceae genera, such as Marivita, Ruegeria, Dinoroseobacter, and Aliiroseovarius, are involved in vital ecological processes, including complex carbohydrate degradation, aerobic denitrification, assimilatory nitrate reduction, ammonium assimilation, and sulfur oxidation. Overall, our study reveals that the common practice of carbohydrate addition in biofloc aquaculture systems fosters the growth of specific heterotrophic bacterial communities, particularly Rhodobacteraceae. These bacteria contribute to maintaining water quality by removing toxic nitrogen and sulfur compounds and enhance animal health by colonizing gut microbiota and exerting probiotic effects.

The Salmonella enterica EnvE is an Outer Membrane Lipoprotein and Its Gene Expression Leads to Transcriptional Repression of the Virulence Gene msgA: Sinyeon Kim, Yong Heon Lee; J. Microbiol. 2024;62(11):1013-1022. Published online November 15, 2024; DOI: https://doi.org/10.1007/s12275-024-00183-4

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Abstract: The envE gene of Salmonella enterica serovar Typhimurium is encoded within Salmonella Pathogenicity Island-11 (SPI-11) and is located immediately upstream of the virulence gene msgA (macrophage survival gene A) in the same transcriptional orientation. To date, the characteristics and roles of envE remain largely unexplored. In this study, we show that EnvE, a predicted lipoprotein, is localized on the outer membrane using sucrose gradient ultracentrifugation. Under oxidative stress conditions, envE transcription is suppressed, while msgA transcription is induced, indicating an inverse correlation between the mRNA levels of the two neighboring genes. Importantly, inactivation of envE leads to constitutive transcription of msgA regardless of the presence of oxidative stress. Moreover, trans-complementation of the envE mutant with a plasmid-borne envE fails to prevent the induction of msgA transcription, suggesting that envE functions as a cis-regulatory element rather than a trans-acting factor. We further show that both inactivation and complementation of envE confer wild-type levels of resistance to oxidative stress by ensuring the expression of msgA. Our data suggest that the S. enterica envE gene encodes an outer membrane lipoprotein, and its transcription represses msgA expression in a cis-acting manner, probably by transcriptional interference, although the exact molecular details are yet unclear.

Description of Streptococcus dentalis sp. nov., Streptococcus gingivalis sp. nov., and Streptococcus lingualis sp. nov., Isolated from Human Oral Cavities: Beom-Jin Goo, Young-Sik Choi, Do-Hun Gim, Su-Won Jeong, Jee-Won Choi, Hojun Sung, Jae-Yun Lee, Jin-Woo Bae; J. Microbiol. 2024;62(11):973-983. Published online November 12, 2024; DOI: https://doi.org/10.1007/s12275-024-00178-1

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Abstract: We isolated three novel strains, S1^T, S2^T, and S5^T, from human oral cavities and identified them as distinct novel species. All these strains are facultatively anaerobic, Gram-stain-positive, and non-flagellated bacteria. Their optimal growth conditions for these strains were observed in Columbia broth (CB) at 37 °C, pH 7.0, and in the absence of NaCl. Phylogenetic analyses, employing the 16S rRNA gene and whole-genome sequencing, confirmed that all three strains belong to the genus Streptococcus. The 16S rRNA gene sequences of strains S1^T, S2^T, and S5^T showed the highest similarities to Streptococcus parasanguinis, 98.57%, 99.05%, and 99.05%, respectively, and the orthologous average nucleotide identity (OrthoANI) values between the three strains and S. parasanguinis were 93.82%, 93.67%, and 94.04%, respectively. The pairwise OrthoANI values between the novel strains were 94.37% (S1^T-S2^T), 95.03% (S2^T-S5^T), and 94.71% (S1^T-S5^T). All strains had C_20:1 ω9c and summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c) as major cellular fatty acids. Additionally, diphosphatidylglycerol (DPG) and hydroxyphosphatidylethanolamine (OH-PE) were identified as major polar lipids. Menaquinone was undetected in all strains. The results from the phylogenetic, phenotypic, chemotaxonomic, and genotypic analyses collectively indicated that strains S1^T, S2^T, and S5^T represent three distinct novel species within the genus Streptococcus, and we propose the names Streptococcus dentalis sp. nov. for strain S1^T (= KCTC 21234^T = JCM 36526^T), Streptococcus gingivalis sp. nov. for strain S2^T (= KCTC 21235^T = JCM 36527^T), and Streptococcus lingualis sp. nov. for strain S5^T (= KCTC 21236^T = JCM 36528^T).

H-NS is a Transcriptional Repressor of the CRISPR-Cas System in Acinetobacter baumannii ATCC 19606: Kyeongmin Kim, Md Maidul Islam, Seunghyeok Bang, Jeongah Kim, Chung-Young Lee, Je Chul Lee, Minsang Shin; J. Microbiol. 2024;62(11):999-1012. Published online November 11, 2024; DOI: https://doi.org/10.1007/s12275-024-00182-5

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Abstract: Acinetobacter baumannii is a multidrug-resistant opportunistic pathogen primarily associated with hospital-acquired infections. The bacterium can gain multidrug resistance through several mechanisms, including horizontal gene transfer. A CRISPR-Cas system including several Cas genes could restrict the horizontal gene transfer. However, the molecular mechanism of CRISPR- Cas transcriptional regulation remains unclear. We identified a type I-F CRISPR-Cas system in A. baumannii ATCC 19606^T standard strain based on sequence analysis. We focused on the transcriptional regulation of Cas3, a key protein of the CRISPR-Cas system. We performed a DNA affinity chromatography-pulldown assay to identify transcriptional regulators of the Cas3 promoter. We identified several putative transcriptional factors, such as H-NS, integration host factor, and HU, that can bind to the promoter region of Cas3. We characterized AbH-NS using size exclusion chromatography and cross-linking experiments and demonstrated that the Cas3 promoter can be regulated by AbH-NS in a concentration-dependent manner via an in vitro transcription assay. CRISPR-Cas expression levels in wild-type and hns mutant strains in the early stationary phase were examined by qPCR and β-galactosidase assay. We found that H-NS can act as a repressor of Cas3. Our transformation efficiency results indicated that the hns mutation decreased the transformation efficiency, while the Cas3 mutation increased it. We report the existence and characterization of the CRISPR-Cas system in A. baumannii 19606^T and demonstrate that AbH-NS is a transcriptional repressor of CRISPR-Cas-related genes in A. baumannii.

An Optimized Method for Reconstruction of Transcriptional Regulatory Networks in Bacteria Using ChIP-exo and RNA-seq Datasets: Minchang Jang, Joon Young Park, Gayeon Lee, Donghyuk Kim; J. Microbiol. 2024;62(12):1075-1088. Published online November 11, 2024; DOI: https://doi.org/10.1007/s12275-024-00181-6

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Abstract: Transcriptional regulatory networks (TRNs) in bacteria are crucial for elucidating the mechanisms that regulate gene expression and cellular responses to environmental stimuli. These networks delineate the interactions between transcription factors (TFs) and their target genes, thereby uncovering the regulatory processes that modulate gene expression under varying environmental conditions. Analyzing TRNs offers valuable insights into bacterial adaptation, stress responses, and metabolic optimization from an evolutionary standpoint. Additionally, understanding TRNs can drive the development of novel antimicrobial therapies and the engineering of microbial strains for biofuel and bioproduct production. This protocol integrates advanced data analysis pipelines, including ChEAP, DEOCSU, and DESeq2, to analyze omics datasets that encompass genome-wide TF binding sites and transcriptome profiles derived from ChIP-exo and RNA-seq experiments. This approach minimizes both the time required and the risk of bias, making it accessible to non-expert users. Key steps in the protocol include preprocessing and peak calling from ChIP-exo data, differential expression analysis of RNA-seq data, and motif and regulon analysis. This method offers a comprehensive and efficient framework for TRN reconstruction across various bacterial strains, enhancing both the accuracy and reliability of the analysis while providing valuable insights for basic and applied research.

Published Erratum

Erratum: Unexpected Requirement of Small Amino Acids at Position 183 for DNA Binding in the Escherichia coli cAMP Receptor Protein: Marcus Carranza, Amanda Rea, Daisy Pacheco, Christian Montiel, Jin Park, Hwan Youn; J. Microbiol. 2024;62(12):1177-1177. Published online November 6, 2024; DOI: https://doi.org/10.1007/s12275-024-00189-y

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Journal Article

Inhibition of Virulence Associated Traits by β-Sitosterol Isolated from Hibiscus rosa-sinensis Flowers Against Candida albicans: Mechanistic Insight and Molecular Docking Studies: Pallvi Mohana, Atamjit Singh, Farhana Rashid, Sharabjit Singh, Kirandeep Kaur, Rupali Rana, Preet Mohinder Singh Bedi, Neena Bedi, Rajinder Kaur, Saroj Arora; J. Microbiol. 2024;62(12):1165-1175. Published online November 6, 2024; DOI: https://doi.org/10.1007/s12275-024-00174-5

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Abstract: The emerging drug resistance and lack of safer and more potent antifungal agents make Candida infections another hot topic in the healthcare system. At the same time, the potential of plant products in developing novel antifungal drugs is also in the limelight. Considering these facts, we have investigated the different extracts of the flowers of Hibiscus rosa-sinensis of the Malvaceae family for their antifungal efficacy against five different pathogenic Candida strains. Among the various extracts, the chloroform extract showed the maximum zone of inhibition (26.6 ± 0.5 mm) against the Candida albicans strain. Furthermore, the chloroform fraction was isolated, and a sterol compound was identified as β-sitosterol. Mechanistic studies were conducted to understand the mechanism of action, and the results showed that β-sitosterol has significant antifungal activity and is capable of interrupting biofilm formation and acts by inhibiting ergosterol biosynthesis in Candida albicans cells. Microscopic and molecular docking studies confirmed these findings. Overall, the study validates the antifungal efficacy of Candida albicans due to the presence of β-sitosterol which can act as an effective constituent for antifungal drug development individually or in combination.

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