Journal of Microbiology

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RapB Regulates Cell Adhesion and Migration in Dictyostelium, Similar to RapA: Uri Han, Nara Han, Byeonggyu Park, Taeck Joong Jeon; J. Microbiol. 2024;62(8):627-637. Published online June 17, 2024; DOI: https://doi.org/10.1007/s12275-024-00143-y

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Abstract: Ras small GTPases act as molecular switches in various cellular signaling pathways, including cell migration, proliferation, and differentiation. Three Rap proteins are present in Dictyostelium; RapA, RapB, and RapC. RapA and RapC have been reported to have opposing functions in the control of cell adhesion and migration. Here, we investigated the role of RapB, a member of the Ras GTPase subfamily in Dictyostelium, focusing on its involvement in cell adhesion, migration, and developmental processes. This study revealed that RapB, similar to RapA, played a crucial role in regulating cell morphology, adhesion, and migration. rapB null cells, which were generated by CRISPR/Cas9 gene editing, displayed altered cell size, reduced cell-substrate adhesion, and increased migration speed during chemotaxis. These phenotypes of rapB null cells were restored by the expression of RapB and RapA, but not RapC. Consistent with these results, RapB, similar to RapA, failed to rescue the phenotypes of rapC null cells, spread morphology, increased cell adhesion, and decreased migration speed during chemotaxis. Multicellular development of rapB null cells remained unaffected. These results suggest that RapB is involved in controlling cell morphology and cell adhesion. Importantly, RapB appears to play an inhibitory role in regulating the migration speed during chemotaxis, possibly by controlling cell-substrate adhesion, resembling the functions of RapA. These findings contribute to the understanding of the functional relationships among Ras subfamily proteins.

Sporosarcina jeotgali sp. nov., Sporosarcina oncorhynchi sp. nov., and Sporosarcina trichiuri sp. nov., Isolated from Jeotgal, a Traditional Korean Fermented Seafood: Ah-In Yang, Bora Kim, Sung-Hong Joe, Hae-In Joe, Hanna Choe, Ki Hyun Kim, Min Ok Jun, Na-Ri Shin; J. Microbiol. 2024;62(4):285-296. Published online April 8, 2024; DOI: https://doi.org/10.1007/s12275-024-00106-3

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Three novel, Gram-stain-positive, obligate aerobic, catalase- and oxidase-positive bacterial strains, designated B2O-1(T), T2O-4(T), and 0.2-SM1T-5(T), were isolated from jeotgal, a traditional Korean fermented seafood. Strains B2O-1(T), T2O-4(T), and 0.2-SM1T-5(T) exhibited distinct colony colors, characterized by pink, yellow, and red opaque circular colonies, respectively. Phylogenetic analysis revealed that three strains formed a paraphyletic clade within the genus Sporosarcina and shared < 99.0% similarity with Sporosarcina aquimarina KCTC 3840(T) and Sporosarcina saromensis KCTC 13119(T) in their 16S rRNA gene sequences. The three strains exhibiting Orthologous Average Nucleotide Identity values < 79.3% and digital DNA-DNA hybridization values < 23.1% within the genus Sporosarcina affirmed their distinctiveness. Strains B2O-1(T), T2O-4(T), and 0.2-SM1T-5(T) contained MK-7 as a sole respiratory menaquinone and A4α type peptidoglycan based on lysine with alanine, glutamic acid, and aspartic acid. The common polar lipids include diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. Strain T2O-4(T) contained one unidentified phospholipid, whereas strain 0.2-SM1T-5(T) contained two unidentified phospholipids. Cellular fatty acid profiles, with C(15:0) anteiso as the major fatty acid, supported the affiliation of the three strains to the genus Sporosarcina. Based on the polyphasic characteristics, strains B2O-1(T) (= KCTC 43506(T) = JCM 36032(T)), T2O-4(T) (= KCTC 43489(T) = JCM 36031(T)), and 0.2-SM1T-5(T) (= KCTC 43519(T) = JCM 36034(T)) represent three novel species within the genus Sporosarcina, named Sporosarcina jeotgali sp. nov., Sporosarcina oncorhynchi sp. nov., and Sporosarcina trichiuri sp. nov., respectively.

Citations

Citations to this article as recorded by

Notification of changes in taxonomic opinion previously published outside the IJSEM. List of Changes in Taxonomic Opinion no. 41
Aharon Oren, Markus Göker
International Journal of Systematic and Evolutionary Microbiology .2025;[Epub] CrossRef
Brevibacterium koreense sp. nov., a moderately halophilic bacterium isolated from jogae-jeotgal, a Korean fermented seafood
Sohee Nam, Yujin Kim, Min Ji Lee, Yeon Bee Kim, Jeong Ui Yun, Mi-Ja Jung, Hye Seon Song, Se Hee Lee, Seok-Jun Kim, Tae Woong Whon
International Journal of Systematic and Evolutionary Microbiology .2025;[Epub] CrossRef
Validation List no. 220. Valid publication of new names and new combinations effectively published outside the IJSEM
Aharon Oren, Markus Göker
International Journal of Systematic and Evolutionary Microbiology .2024;[Epub] CrossRef

Minimal amino acids in the I/LWEQ domain required for anterior/posterior localization in Dictyostelium: Hyeseon Kim , Dong-Yeop Shin , Taeck Joong Jeon; J. Microbiol. 2017;55(5):366-372. Published online January 26, 2017; DOI: https://doi.org/10.1007/s12275-017-6550-0

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1 Scopus

Abstract: Establishment of cell polarity is mediated by a series of signal-ing molecules that are asymmetrically activated or localized in the cell upon extracellular stimulation. To understand the mechanism that mediates anterior/posterior asymmetric localization of RapGAP3 during migration, we determined the minimally required amino acids in the I/LWEQ domain that cause posterior localization and found that the minimal region of the F-actin binding domain for posterior localiza-tion could, with some additional deletion at the C-terminal, localize to the anterior. Analysis of the localization and trans-location kinetics to the cell cortex of the truncated proteins suggests that the required regions for anterior/posterior lo-calization might have a preferential binding affinity to pre- existing F-actins at the rear and lateral sides of the cell or newly formed F-actins at the front of the cell, leading to dis-tinct differential sites of the cell.

Review

REVIEW] Cell Migration: Regulation of Cytoskeleton by Rap1 in Dictyostelium discoideum: Mi-Rae Lee , Taeck J. Jeon; J. Microbiol. 2012;50(4):555-561. Published online August 25, 2012; DOI: https://doi.org/10.1007/s12275-012-2246-7

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31 Scopus

Abstract: Cell movement involves a coordinated regulation of the cytoskeleton, F-actin-mediated protrusions at the front and myosin-mediated contraction of the posterior of a cell. The small GTPase Rap1 functions as a key regulator in the spatial and temporal control of cytoskeleton reorganization for cell migration. This review outlines the establishment of cell polarity by differential localizations of the cytoskeleton and discusses the spatial and temporal regulation of cytoskeleton
reorganization via the Rap1 signaling pathway during chemotaxis with a focus on recent advances in the study of chemotaxis using a simple eukaryotic model organism, Dictyostelium discoideum.

Research Support, Non-U.S. Gov't

Berberine Inhibits HEp-2 Cell Invasion Induced by Chlamydophila pneumoniae Infection: Li Jun Zhang , Li Jun Zhang , Wei Quan , Bei Bei Wang , Bing Ling Shen , Teng Teng Zhang , Yi Kang; J. Microbiol. 2011;49(5):834-840. Published online November 9, 2011; DOI: https://doi.org/10.1007/s12275-011-1051-z

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Abstract: This study investigated the inhibitory effects of berberine on Chlamydophila (Chlamydia) pneumoniae infection-induced HEp-2 cell invasion and explored the possible mechanisms involved in this process. C. pneumoniae infection resulted in a significant increase in HEp-2 cell invasion when compared with the control cells (P<0.01) in a Matrigel invasion assay. This enhanced cell invasion was strongly suppressed by berberine (50 μM) (P<0.01). In a cell adhesion assay, the infection-induced HEp-2 cell adhesion to Matrigel was also significantly inhibited by berberine (P<0.01). C. pneumoniae infection was found to promote HEp-2 cell migration remarkably (P<0.01), which was markedly suppressed by berberine (P<0.01) in the cell migration assays. There were no statistically significant differences in the expression of matrix metalloproteinase-1 (MMP-1) and MMP-9 in the infected cells and berberine did not change the expression of MMP-1 and MMP-9. These data suggest that berberine inhibits C. pneumoniae infection-induced HEp-2 cell invasion through suppressing HEp-2 cell adhesion and migration, but not through changing the expression of MMP-1 and MMP-9.

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