Molecular Microbiology最新文献

{"title":"An Escherichia coli Phosphotransferase System Modulates Methylglyoxal Resistance by Regulating Intracellular Potassium.","authors":"Sara Alexander,Mark Goulian","doi":"10.1111/mmi.70068","DOIUrl":"https://doi.org/10.1111/mmi.70068","url":null,"abstract":"Methylglyoxal is a toxic aldehyde produced during cellular metabolism across all domains of life. To cope with methylglyoxal stress, Escherichia coli employs the glyoxalase detoxification pathway coupled with Kef-mediated potassium/proton antiport. However, the Kef system is protective only when extracellular potassium is well below concentrations typically found in mammalian hosts. The regulatory phosphotransferase system (PTS) that is historically known as the nitrogen-related PTS (PTSNtr) has previously been shown to modulate potassium homeostasis and other processes in E. coli. Here, we identified this regulatory PTS as a mediator of methylglyoxal resistance for potassium concentrations that are comparable to those encountered in the context of host colonization or infection. We found that loss of unphosphorylated PtsN increases survival in methylglyoxal, and that this depended on the potassium/proton antiporter YcgO, whose activity decreases intracellular potassium and pH. While cytoplasmic acidification has been hypothesized to underlie protection from methylglyoxal via potassium/proton antiport, our results suggest the effects of acidification and intracellular potassium cannot be easily separated. Loss of potassium import through Trk increased survival in methylglyoxal and decreased intracellular potassium with only a relatively small decrease in pH. Moreover, the addition of acetate, which acidifies the cytoplasm and protects cells from methylglyoxal, also decreased intracellular potassium. Our results demonstrate that for extracellular potassium levels relevant for host infection and colonization, PtsN modulates methylglyoxal resistance by regulating potassium transport, and that low intracellular potassium, in addition to acidification, could play a direct role in protecting against methylglyoxal stress.","PeriodicalId":19006,"journal":{"name":"Molecular Microbiology","volume":"22 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2026-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147641777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regulatory Activity Switching by NtrX Rescues the Stress Phenotypes Caused by Loss of ChvIG in Caulobacter crescentus.","authors":"Anne Amalie Winther Faber, Michelle Nielsen, Vishnu Narayanan Madhavan, Lykke Haastrup Hansen, Clare L Kirkpatrick","doi":"10.1111/mmi.70055","DOIUrl":"10.1111/mmi.70055","url":null,"abstract":"<p><p>Two-component systems, comprising a sensor kinase and a response regulator, are very important for bacteria to respond to stress in their environment. In alpha-proteobacteria, two such systems (ChvIG and NtrYX) help bacteria to respond to cell envelope and acid stress, respectively. In contrast to the majority of two-component systems, which do not cross talk with one another, ChvIG and NtrYX in Caulobacter are tightly functionally linked and regulate many of the same genes. Moreover, the antagonistic balance between phosphorylated ChvI and non-phosphorylated NtrX is essential for growth in defined medium. We show that the NtrX-ChvI balance is also critical for swimming motility in defined medium (M2G) stress conditions, and that loss of motility in M2G in ΔchvI or ΔchvG mutants is rescued by dominant gain-of-function mutations in ntrYX. These mutations promote a regulatory switch of NtrX away from the genes that are regulated by NtrX in its non-phosphorylated form, at least one of which is jointly bound by ChvI and NtrX at the same binding site. The data support a model where these two systems co-operate tightly as a stress response mediator, almost to the extent that they could be considered a four-component system, and that ChvI is required for NtrX to regulate some of its target genes.</p>","PeriodicalId":19006,"journal":{"name":"Molecular Microbiology","volume":" ","pages":"308-327"},"PeriodicalIF":3.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146150441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Ti Plasmid‐Encoded VirJ Functions as a Lysyl‐Phosphatidylglycerol Hydrolase in Agrobacterium tumefaciens ","authors":"Britta Lotz, Lina Brodskaia, Christiane Fritz, Stefanie Hebecker, Maike K. Tauchert, Jennifer Breisch, Dieter Jahn, Franz Narberhaus, Jürgen Moser, Meriyem Aktas","doi":"10.1111/mmi.70061","DOIUrl":"https://doi.org/10.1111/mmi.70061","url":null,"abstract":"<jats:styled-content style=\"fixed-case\"> <jats:italic>Agrobacterium tumefaciens</jats:italic> </jats:styled-content> delivers oncogenic transfer DNA (T‐DNA) into plants via a type IV secretion system (T4SS). This process requires virulence factors from the tumor‐inducing (Ti) plasmid and chromosomal genes such as <jats:italic>acvB</jats:italic> . We previously identified AcvB as a lysyl‐phosphatidylglycerol (L‐PG) hydrolase. Loss of AcvB in the nopaline‐type strain C58 increases membrane L‐PG levels, thereby compromising T‐DNA transfer. Interestingly, octopine‐type strains harbor an additional truncated <jats:italic>acvB</jats:italic> homologue, <jats:italic>virJ</jats:italic> , on the Ti plasmid. The established L‐PG hydrolase function of AcvB and its similarity to VirJ motivated us to investigate the enzymatic function of VirJ. Purified recombinant VirJ hydrolyzed L‐PG to phosphatidylglycerol and lysine. Transient <jats:italic>virJ</jats:italic> expression in an <jats:italic>acvB</jats:italic> deletion strain reduced elevated L‐PG levels, rescuing impaired growth under acidic conditions and defective T‐DNA transfer. These results provide the first direct evidence that VirJ functions as an L‐PG hydrolase and demonstrate that its enzymatic activity in maintaining L‐PG homeostasis is crucial for T‐DNA transfer. Importantly, elevated L‐PG levels did not disrupt T4SS assembly but likely compromised its functionality once formed. In contrast, L‐PG excess did not affect the conjugative RP4 T4SS or the type VI secretion system. Together, these findings highlight a secretion system‐specific reliance on membrane lipid composition.","PeriodicalId":19006,"journal":{"name":"Molecular Microbiology","volume":"11 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2026-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147465327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gut Microbiota-Derived Extracellular Vesicles in Patients With Obesity Undergoing Gastric Bypass Surgery.","authors":"Jenni Hekkala,Anna Kaisanlahti,Mysore V Tejesvi,Jenni Turunen,Nikke Virtanen,Sonja Karikka,Pande Putu Erawijantari,Anatoliy Samoylenko,Genevieve Bart,Seppo Vainio,Leo Lahti,Janne Hukkanen,Terhi Ruuska-Loewald,Vesa Koivukangas,Justus Reunanen","doi":"10.1111/mmi.70064","DOIUrl":"https://doi.org/10.1111/mmi.70064","url":null,"abstract":"Human gut microbiota is associated with obesity. Gut microbiota-derived extracellular vesicles (EVs), lipid coated nanoparticles secreted by bacteria, have been suggested as a communication mechanism between gut microbiota and the host. This study characterized the effect of Roux-en-Y gastric bypass (RYGB) on gut microbiota and gut microbiota-derived EVs in patients with obesity. Fecal samples were collected from 30 recruited patients at baseline and 6 months after surgery. EVs were isolated from fecal samples, and their origin and protein content were analyzed. The number of unique proteins was increased in gut microbiota-derived EVs after the surgery as compared to baseline. A significant difference in both microbiota composition (p = 0.001; PERMANOVA) and microbiota-derived EVs (p = 0.001; PERMANOVA) was observed in response to surgery. Based on 16S rRNA gene sequencing data, a random forest classifier accurately classified both gut microbiota (AUC = 0.93) and EVs (AUC = 0.80) to baseline and after surgery groups. This study found that gastric bypass surgery altered both the composition and characteristics of gut microbiota and gut microbiota-derived EVs in patients with obesity. Thus, gut microbiota-derived EVs may play a role in obesity and influence the health effects of bariatric surgery beyond the gut. Trial Registration: ClinicalTrials.gov identifier: NCT00950003.","PeriodicalId":19006,"journal":{"name":"Molecular Microbiology","volume":"124 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2026-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147439480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acidic pH Restricts Non-Tuberculous Mycobacteria Replication.","authors":"Parise K Lockwood,Luiz Pedro Sorio de Carvalho,Rachel P J Lai,Maximiliano G Gutierrez","doi":"10.1111/mmi.70060","DOIUrl":"https://doi.org/10.1111/mmi.70060","url":null,"abstract":"Non-tuberculous mycobacteria (NTM) are becoming increasingly prevalent in clinical settings with certain environmental species becoming opportunistic in both immunocompetent and immunodeficient hosts. However, the factors that drive this environmental-to-opportunistic switch remain poorly understood. NTM are environmental organisms that commonly thrive in acidic niches. Conversely, in host cells, acidic pH acts as a defence mechanism. Here, we investigated how acidic pH impacts NTM replication both in vitro and in cellulo. A set of 12 NTM, representing both environmental and opportunistic bacteria, was assessed for growth across a pH range of 4.5-8.0 in vitro, revealing that acid tolerance was species specific. Fluorescent NTM reporters were generated and used to track real-time live cell intracellular replication within human macrophages where acid tolerant species in vitro replicated with a higher efficiency in cellulo than acid sensitive NTM. Further neutralisation of the phagosomal pH using bafilomycin A1 (BafA1) led to enhanced intracellular replication and survival of NTM. This study demonstrated that specific environmental adaptations may determine the opportunistic potential of NTM whilst acidic pH within the host serves as a key host defence mechanism to restrict NTM growth.","PeriodicalId":19006,"journal":{"name":"Molecular Microbiology","volume":"127 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2026-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147374153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Hemoprotein Hhy1 Promotes Heme-Dependent Catalase Activity of Ctt1.","authors":"Tobias Vahsen,Samuel Plante,Berthy Mbuya,Simon Labbé","doi":"10.1111/mmi.70062","DOIUrl":"https://doi.org/10.1111/mmi.70062","url":null,"abstract":"In this study, we generated a Schizosaccharomyces pombe strain deficient in heme and siderophore biosynthesis, as well as in reductive iron uptake. Using this hem1Δ sib1Δ sib2Δ fio1Δ fip1Δ mutant strain, we identified Hhy1, a novel protein required for optimal growth when cells rely on exogenous hemin as their sole source of heme. The expression of Hhy1 is upregulated under low-iron conditions and downregulated when iron levels increase. Fluorescence microscopy analysis shows that the Hhy1-GFP fluorescent signal mirrors hhy1+ mRNA expression, being primarily detected in the cytoplasm of iron-starved hem1Δ sib1Δ sib2Δ fio1Δ fip1Δ cells. Further monitoring of intracellular heme or its analog zinc mesoporphyrin IX revealed that hem1Δ sib1Δ sib2Δ fio1Δ fip1Δ cells lacking Hhy1 accumulate these molecules more persistently than cells expressing Hhy1. Consistent with a role for Hhy1 in heme homeostasis, hhy1Δ cells exhibit reduced heme-dependent activity of the catalase Ctt1. Coimmunoprecipitation and bimolecular fluorescence complementation experiments show that Hhy1 interacts with Ctt1. Absorbance spectroscopy and hemin-agarose pull-down assays demonstrate that Hhy1 binds hemin, with an equilibrium dissociation constant of 1.09 μM. Taken together, these findings indicate that the iron-regulated cytoplasmic hemoprotein Hhy1 interacts with Ctt1, promoting its full activation against oxidative stress under hemin-dependent growth conditions.","PeriodicalId":19006,"journal":{"name":"Molecular Microbiology","volume":"58 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2026-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147374200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Erythrocyte Membrane Protein 3 (EMAP3) Is Exposed on the Surface of the Plasmodium berghei Infected Red Blood Cell.","authors":"Sophia Raine C Hernandez, Ravish Rashpa, Thorey K Jonsdottir, Martina S Paoletta, Josy Ter Beek, María Rayón Díaz, Jelte M M Krol, Severine Chevalley-Maurel, Takahiro Ishizaki, Ronnie P-A Berntsson, Chris J Janse, Blandine Franke-Fayard, Mathieu Brochet, Ellen S C Bushell","doi":"10.1111/mmi.70050","DOIUrl":"10.1111/mmi.70050","url":null,"abstract":"<p><p>The human malaria parasite Plasmodium falciparum invades red blood cells (RBCs) and exports parasite proteins to transform the host cell for its survival. These exported proteins facilitate cytoadherence of the infected RBC (iRBC) to endothelial cells of small blood vessels, protecting iRBCs from splenic clearance. The parasite protein PfEMP1 and the host protein CD36 play a major role in P. falciparum iRBC cytoadherence. The murine parasite Plasmodium berghei is a widely used experimental model that combines high genetic tractability with access to in vivo studies. The P. berghei iRBC also sequesters by CD36-binding via an unknown parasite ligand and few parasite proteins, including EMAP1 and EMAP2, have been localised to the iRBC membrane. We have identified a new protein named EMAP3 and demonstrated its export to the iRBC membrane where it likely interacts with EMAP1, with only EMAP3 exposed on the outer surface of the iRBC. Parasites lacking EMAP3 display no significant reduction in growth or sequestration, indicating that EMAP3 is not a major CD36-binding protein. The outer-surface location of EMAP3 offers a new scaffold for displaying P. falciparum proteins on the surface of the P. berghei iRBC, providing a platform to screen in vivo for putative inhibitors of P. falciparum cytoadherence.</p>","PeriodicalId":19006,"journal":{"name":"Molecular Microbiology","volume":" ","pages":"233-249"},"PeriodicalIF":3.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12956039/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146011218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Undecaprenyl Pyrophosphate Phosphatase (UppP) is a Pivotal Element in Salmonella Intramacrophage Survival.","authors":"Rhea Vij, Debapriya Mukherjee, Kirti Parmar, Krishna Chaitanya Nallamotu, Manjula Reddy, Dipshikha Chakravortty","doi":"10.1111/mmi.70052","DOIUrl":"10.1111/mmi.70052","url":null,"abstract":"<p><p>To establish infection, Salmonella confronts a dynamic barrage of host-induced stresses. The peptidoglycan layer is essential for maintaining bacterial cell integrity and counteracting these environmental stress. Its synthesis relies on the lipid carrier undecaprenyl phosphate, which is generated by the enzyme undecaprenyl pyrophosphate phosphatase (UppP). While UppP is linked to virulence in other pathogens, its role in Salmonella remains unclear. We show that an uppP mutant in S. Typhimurium exhibits altered cell morphology, reduced stiffness, and impaired survival in RAW 264.7 macrophages. The mutant is also attenuated in systemic infection in C57BL/6 mice. These defects are associated with increased sensitivity to nitrosative stress. Notably, iNOS inhibition or deficiency restores intracellular survival of the uppP mutant in both RAW 264.7 macrophages and the mouse model, implicating UppP in resistance to nitrosative stress. Our findings reveal a critical role for UppP in promoting Salmonella survival within macrophages and contributing to systemic pathogenesis.</p>","PeriodicalId":19006,"journal":{"name":"Molecular Microbiology","volume":" ","pages":"268-288"},"PeriodicalIF":3.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146011284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SanA Plays a Role in Peptidoglycan Integrity in Escherichia coli","authors":"Honoka Yamaguchi, Risa Ago, Yuhei O. Tahara, Mari Inoue, Hironori Niki, Makoto Miyata, Daisuke Shiomi","doi":"10.1111/mmi.70058","DOIUrl":"https://doi.org/10.1111/mmi.70058","url":null,"abstract":"Peptidoglycan synthesis and degradation are both essential for bacterial growth, and damaged peptidoglycan must be continuously repaired. In <jats:styled-content style=\"fixed-case\"> <jats:italic>Escherichia coli</jats:italic> </jats:styled-content> , peptidoglycan required for cell elongation is synthesized by the Rod complex. Although RodZ is a non‐essential component of this complex, its dysfunction leads to aberrant peptidoglycan synthesis, resulting in defects in cell shape and impaired growth. We previously isolated several suppressor mutants that restore growth in cells with impaired RodZ function (RMR cells). Most suppressor mutations mapped to components in the Rod complex other than RodZ. However, one suppressor mutation was identified in <jats:italic>sanA</jats:italic> , a gene not previously associated with the Rod complex. This mutation, <jats:italic>sanA</jats:italic> <jats:sup> <jats:italic>M27R</jats:italic> </jats:sup> , represents a loss‐of‐function allele. Here, we show that SanA is associated with PBP1B, a non‐essential yet physiologically important peptidoglycan synthase. Loss of SanA function partially restored the growth of RMR cells, accompanied by enhanced peptidoglycan synthesis and alleviation of structural defects in the cell wall. These findings indicate that SanA contributes to the regulation of peptidoglycan synthesis and cell wall integrity, potentially through functional interplay with PBP1B‐dependent pathways.","PeriodicalId":19006,"journal":{"name":"Molecular Microbiology","volume":"320 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2026-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146230785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Perfectly Coupled Transcriptional Regulation of Fatty Acid Synthesis in Enterocci, Streptocci, and Lactococci","authors":"Qi Zou, John E. Cronan","doi":"10.1111/mmi.70054","DOIUrl":"https://doi.org/10.1111/mmi.70054","url":null,"abstract":"&lt;p&gt;The fatty acid synthesis operon of &lt;i&gt;Enterococcus faecalis&lt;/i&gt; and similar operons in related pathogenic bacteria are unusual in that &lt;i&gt;fabT&lt;/i&gt;, the gene encoding the transcriptional repressor, is the first gene of the multigene fatty acid synthesis operon that it regulates (Figure 1). Therefore, the levels of FabT and the operon encoded enzymes are coordinated because they are encoded on the same mRNA. This is the case in &lt;i&gt;E. faecalis&lt;/i&gt; (Bi et al. &lt;span&gt;2014&lt;/span&gt;; Hays et al. &lt;span&gt;2021&lt;/span&gt;; Zhu et al. &lt;span&gt;2019&lt;/span&gt;; Zou et al. &lt;span&gt;2022&lt;/span&gt;), the streptococci (e.g., &lt;i&gt;Streptococcus pneumoniae&lt;/i&gt;) (Jerga and Rock &lt;span&gt;2009&lt;/span&gt;; Yao and Rock &lt;span&gt;2015&lt;/span&gt;, &lt;span&gt;2017&lt;/span&gt;) (Lambert et al. &lt;span&gt;2022&lt;/span&gt;) and lactococci (Eckhardt et al. &lt;span&gt;2013&lt;/span&gt;). Moreover, the FabT regulatory ligands, acyl-ACPs, which bind FabT to increase operator binding (Jerga and Rock &lt;span&gt;2009&lt;/span&gt;; Zhu et al. &lt;span&gt;2019&lt;/span&gt;; Zou et al. &lt;span&gt;2022&lt;/span&gt;; Lambert et al. &lt;span&gt;2023&lt;/span&gt;, &lt;span&gt;2022&lt;/span&gt;), are produced by genes regulated by FabT.&lt;/p&gt;\u0000&lt;figure&gt;&lt;picture&gt;\u0000&lt;source media=\"(min-width: 1650px)\" srcset=\"/cms/asset/29a353fb-646c-4e53-a859-f4b8b6cf3c30/mmi70054-fig-0001-m.jpg\"/&gt;&lt;img alt=\"Details are in the caption following the image\" data-lg-src=\"/cms/asset/29a353fb-646c-4e53-a859-f4b8b6cf3c30/mmi70054-fig-0001-m.jpg\" loading=\"lazy\" src=\"/cms/asset/0e25de5c-b305-4c06-8b36-bdbbfc86b5c9/mmi70054-fig-0001-m.png\" title=\"Details are in the caption following the image\"/&gt;&lt;/picture&gt;&lt;figcaption&gt;\u0000&lt;div&gt;&lt;strong&gt;FIGURE 1&lt;span style=\"font-weight:normal\"&gt;&lt;/span&gt;&lt;/strong&gt;&lt;div&gt;Open in figure viewer&lt;i aria-hidden=\"true\"&gt;&lt;/i&gt;&lt;span&gt;PowerPoint&lt;/span&gt;&lt;/div&gt;\u0000&lt;/div&gt;\u0000&lt;div&gt;Fatty acid metabolism in the Lactobacillales and the &lt;i&gt;E. faecalis&lt;/i&gt; fatty acid metabolism operons. (A) The pathways of de novo synthesis and of exogenous fatty acid incorporation. (B) The twelve gene &lt;i&gt;E. faecalis&lt;/i&gt; FabT operon is transcribed from the blue promoter and transcription proceeds from upstream of &lt;i&gt;fabT&lt;/i&gt; through &lt;i&gt;accA&lt;/i&gt; (Bi et al. &lt;span&gt;2014&lt;/span&gt;; Hays et al. &lt;span&gt;2021&lt;/span&gt;). The operon &lt;i&gt;fabK&lt;/i&gt; gene is cryptic (Bi et al. &lt;span&gt;2014&lt;/span&gt;). The &lt;i&gt;fabI, fabO&lt;/i&gt;, and &lt;i&gt;fabN&lt;/i&gt; genes are part of the FabT regulon whereas the &lt;i&gt;plsX&lt;/i&gt;, &lt;i&gt;acpB&lt;/i&gt;, and &lt;i&gt;fakAB&lt;/i&gt; genes are not (Dong et al. &lt;span&gt;2025&lt;/span&gt;; Zou et al. &lt;span&gt;2022&lt;/span&gt;). AcpB functions in fatty acid incorporation and FabT repression but cannot replace AcpA (Dong and Cronan &lt;span&gt;2022&lt;/span&gt;; Zhu et al. &lt;span&gt;2019&lt;/span&gt;). FabT is a member of the MarR family of dimeric winged helix-turn-helix proteins (Deochand and Grove &lt;span&gt;2017&lt;/span&gt;; Zuo et al. &lt;span&gt;2019&lt;/span&gt;). Note that streptococcal operons have a FabT-regulated promoter located between the &lt;i&gt;acpA&lt;/i&gt; and &lt;i&gt;fabK&lt;/i&gt; genes (Lu and Rock &lt;span&gt;2006&lt;/span&gt;) that is absent in &lt;i&gt;E. faecalis&lt;/i&gt; (Bi et al. &lt;span&gt;2014&lt;/span&gt;; Hays et al. &lt;span&gt;2021&lt;/span&gt;).&lt;/div&gt;\u0000&lt;/figcaption&gt;\u0000&lt;/figure&gt;\u0000&lt;p&gt;The conservation of","PeriodicalId":19006,"journal":{"name":"Molecular Microbiology","volume":"20 1","pages":""},"PeriodicalIF":3.6,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146204972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}