Biofilm最新文献

{"title":"Effect of mutanase and dextranase on biofilms of cariogenic bacteria: A systematic review of in vitro studies","authors":"Yumi C. Del Rey ,&nbsp;Hian Parize ,&nbsp;Sahar Assar ,&nbsp;Gerd Göstemeyer ,&nbsp;Sebastian Schlafer","doi":"10.1016/j.bioflm.2024.100202","DOIUrl":"10.1016/j.bioflm.2024.100202","url":null,"abstract":"<div><p>Matrix-degrading enzymes are promising non-biocidal adjuncts to dental biofilm control and caries prevention. By disrupting the biofilm matrix structure, enzymes may prevent biofilm formation or disperse established biofilms without compromising the microbial homeostasis in the mouth. This study reviewed whether treatment with mutanase and/or dextranase inhibits cariogenic biofilm growth and/or removes cariogenic biofilms <em>in vitro</em>. An electronic search was conducted in PubMed, EMBASE, Scopus, Web of Science, Cochrane, and LIVIVO databases. Manual searches were performed to identify additional records. Studies that quantitatively measured the effect of mutanase and/or dextranase on the inhibition/removal of <em>in vitro</em> cariogenic biofilms were considered eligible for inclusion. Out of 809 screened records, 34 articles investigating the effect of dextranase (n = 23), mutanase (n = 10), and/or combined enzyme treatment (n = 7) were included in the review. The overall risk of bias of the included studies was moderate. Most investigations used simple biofilm models based on one or few bacterial species and employed treatment times ≥30 min. The current evidence suggests that mutanase and dextranase, applied as single or combined treatment, are able to both inhibit and remove <em>in vitro</em> cariogenic biofilms. The pooled data indicate that enzymes are more effective for biofilm inhibition than removal, and an overall higher effect of mutanase compared to dextranase was observed.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100202"},"PeriodicalIF":6.8,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000273/pdfft?md5=3184bd6bd7e4cb899319ea1aa2fd440a&pid=1-s2.0-S2590207524000273-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141144635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New insights into the antibiofilm activity and mechanism of Mannosylerythritol Lipid-A against Listeria monocytogenes EGD-e","authors":"Xiayu Liu ,&nbsp;Siyu Liu ,&nbsp;Yuxi Wang ,&nbsp;Ying Shi ,&nbsp;Qihe Chen","doi":"10.1016/j.bioflm.2024.100201","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100201","url":null,"abstract":"<div><p><em>Listeria monocytogenes</em> is one of the leading causative agents of foodborne disease outbreaks worldwide. Herein, the antibiofilm effect and mechanism of Mannosylerythritol Lipid-A against <em>L. monocytogenes</em> EGD-e is reported for the first time. MEL-A effectively attenuated biofilm formation while reducing the viability and motility of bacteria within the biofilm in the early stage, and influenced bacterial adhesion by affecting the secretion of extracellular polysaccharides and eDNA. RT-qPCR revealed that MEL-A significantly suppressed the expression of genes involved in flagellar movement and virulence. Untargeted LC-MS metabolomics indicated that MEL-A affected the fluidity and permeability of cell membranes by significantly upregulating unsaturated fatty acids, lipids and glycoside metabolites, and affected protein biosynthesis, nucleotide metabolism and DNA synthesis and repair by significantly downregulating amino acid metabolism and nucleic acid metabolism. These pathways may constitute the key targets of biofilm formation inhibition by MEL-A. Furthermore, MEL-A showed good removal effects on mature biofilms under different temperatures, different materials and milk. Our data indicated that MEL-A could be used as a novel antibiofilm agent to improve food safety. Our study provides new insights into the possible inhibitory mechanism of MEL-A and the response of <em>L. monocytogenes</em> EGD-e to MEL-A.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100201"},"PeriodicalIF":6.8,"publicationDate":"2024-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000261/pdfft?md5=f1b0e418cf1852ec6527fc3d1bbf3e94&pid=1-s2.0-S2590207524000261-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140918332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bacterial micro-aggregates as inoculum in animal models of implant-associated infections","authors":"Katrine Top Hartmann ,&nbsp;Regitze Lund Nielsen ,&nbsp;Freja Cecilie Mikkelsen ,&nbsp;Bent Aalbæk ,&nbsp;Mads Lichtenberg ,&nbsp;Tim Holm Jakobsen ,&nbsp;Thomas Bjarnsholt ,&nbsp;Lasse Kvich ,&nbsp;Hanne Ingmer ,&nbsp;Anders Odgaard ,&nbsp;Henrik Elvang Jensen ,&nbsp;Louise Kruse Jensen","doi":"10.1016/j.bioflm.2024.100200","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100200","url":null,"abstract":"<div><p>Is it time to rethink the inoculum of animal models of implant-associated infections (IAI)? Traditionally, animal models of IAI are based on inoculation with metabolically active overnight cultures of planktonic bacteria or pre-grown surface-attached biofilms. However, such inoculums do not mimic the clinical initiation of IAI. Therefore, the present study aimed to develop a clinically relevant inoculum of low metabolic micro-aggregated bacteria. The porcine <em>Staphylococcus aureus</em> strain S54F9 was cultured in Tryptone Soya Broth (TSB) for seven days to facilitate the formation of low metabolic micro-aggregates. Subsequently, the aggregated culture underwent filtration using cell strainers of different pore sizes to separate micro-aggregates. Light microscopy was used to evaluate the aggregate formation and size in the different fractions, while isothermal microcalorimetry was used to disclose a low metabolic activity. The micro-aggregate fraction obtained with filter size 5–15 μm (actual measured mean size 32 μm) was used as inoculum in a porcine implant-associated osteomyelitis (IAO) model and compared to a standard overnight planktonic inoculum and a sham inoculum of 0.9 % saline. The micro-aggregate and planktonic inoculums caused IAO with the re-isolation of <em>S. aureus</em> from soft tissues, bones, and implants. However, compared to their planktonic counterpart, neither of the micro-aggregate inoculated animals showed signs of osteomyelitis, i.e., sequester, osteolysis, and pus at gross inspection. Furthermore, inoculation with low metabolic micro-aggregates resulted in a strong healing response with pronounced osteoid formation, comparable to sham animals. In conclusion, the formation and separation of low metabolic bacterial micro-aggregates into various size fractions is possible, however, planktonic bacteria were still seen in all size fractions. Inoculation with micro-aggregates caused a less-aggressive osteomyelitis i.e. combination of infected tissue and strong healing response. Therefore, the use of low metabolic micro-aggregates could be a relevant inoculum for animal models of less-aggressive and thereby slower developing IAI and add in to our understanding of the host-implant-bacteria interactions in slow-onset low-grade infections.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100200"},"PeriodicalIF":6.8,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S259020752400025X/pdfft?md5=60bfb6f708f5b0db56a8c995af62be27&pid=1-s2.0-S259020752400025X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140951909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of dental material type and masticatory forces on periodontitis-derived subgingival microbiomes","authors":"Carolina Montoya ,&nbsp;Divyashri Baraniya ,&nbsp;Tsute Chen ,&nbsp;Nezar Noor Al-Hebshi ,&nbsp;Santiago Orrego","doi":"10.1016/j.bioflm.2024.100199","DOIUrl":"10.1016/j.bioflm.2024.100199","url":null,"abstract":"<div><p>Restorative dental materials can frequently extend below the gingival margin, serving as a potential haven for microbial colonization, and altering the local oral microbiome to ignite infection. However, the contribution of dental materials on driving changes of the composition of the subgingival microbiome is under-investigated. This study evaluated the microbiome-modulating properties of three biomaterials, namely resin dental composites (COM), antimicrobial piezoelectric composites (BTO), and hydroxyapatite (HA), using an optimized <em>in vitro</em> subgingival microbiome model derived from patients with periodontal disease. Dental materials were subjected to static or cyclic loading (mastication forces) during biofilm growth. Microbiome composition was assessed by 16S rRNA gene sequencing. Dysbiosis was measured in terms of subgingival microbial dysbiosis index (SMDI). Biomaterials subjected to cyclic masticatory loads were associated with enhanced biofilm viability except on the antibacterial composite. Biomaterials held static were associated with increased biofilm biomass, especially on HA surfaces. Overall, the microbiome richness (Chao index) was similar for all the biomaterials and loading conditions. However, the microbiome diversity (Shannon index) for the HA beams was significantly different than both composites. In addition, beta diversity analysis revealed significant differences between composites and HA biomaterials, and between both loading conditions (static and cyclic). Under static conditions, microbiomes formed over HA surfaces resulted in increased dysbiosis compared to composites through the enrichment of periopathogens, including <em>Porphyromonas gingivalis</em>, <em>Porphyromonas endodontalis</em>, and <em>Fretibacterium</em> spp., and depletion of commensals such as <em>Granulicatella</em> and <em>Streptococcus</em> spp. Interestingly, cyclic loading reversed the dysbiosis of microbiomes formed over HA (depletion of periopathogenes) but increased the dysbiosis of microbiomes formed over composites (enrichment of <em>Porphyromonas gingivalis</em> and <em>Fusobacterim nucleatum</em>). Comparison of species formed on both composites (control and antibacterial) showed some differences. Commercial composites enriched <em>Selenomonas</em> spp. and depleted <em>Campylobacter concisus</em>. Piezoelectric composites effectively controlled the microbiome viability without significantly impacting the species abundance. Findings of this work open new understandings of the effects of different biomaterials on the modulation of oral biofilms and the relationship with oral subgingival infections.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100199"},"PeriodicalIF":6.8,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000248/pdfft?md5=5a8193683ae54ec096672f9e91d77822&pid=1-s2.0-S2590207524000248-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141051980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phenotypic and proteomic differences in biofilm formation of two Lactiplantibacillus plantarum strains in static and dynamic flow environments","authors":"Linda Huijboom ,&nbsp;Parisa Rashtchi ,&nbsp;Marcel Tempelaars ,&nbsp;Sjef Boeren ,&nbsp;Erik van der Linden ,&nbsp;Mehdi Habibi ,&nbsp;Tjakko Abee","doi":"10.1016/j.bioflm.2024.100197","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100197","url":null,"abstract":"<div><p><em>Lactiplantibacillus plantarum</em> is a Gram-positive non-motile bacterium capable of producing biofilms that contribute to the colonization of surfaces in a range of different environments. In this study, we compared two strains, WCFS1 and CIP104448, in their ability to produce biofilms in static and dynamic (flow) environments using an in-house designed flow setup. This flow setup enables us to impose a non-uniform flow velocity profile across the well. Biofilm formation occurred at the bottom of the well for both strains, under static and flow conditions, where in the latter condition, CIP104448 also showed increased biofilm formation at the walls of the well in line with the higher hydrophobicity of the cells and the increased initial attachment efficacy compared to WCFS1. Fluorescence and scanning electron microscopy showed open 3D structured biofilms formed under flow conditions, containing live cells and ∼30 % damaged/dead cells for CIP104448, whereas the WCFS1 biofilm showed live cells closely packed together. Comparative proteome analysis revealed minimal changes between planktonic and static biofilm cells of the respective strains suggesting that biofilm formation within 24 h is merely a passive process. Notably, observed proteome changes in WCFS1 and CIP104448 flow biofilm cells indicated similar and unique responses including changes in metabolic activity, redox/electron transfer and cell division proteins for both strains, and myo-inositol production for WCFS1 and oxidative stress response and DNA damage repair for CIP104448 uniquely. Exposure to DNase and protease treatments as well as lethal concentrations of peracetic acid showed highest resistance of flow biofilms. For the latter, CIP104448 flow biofilm even maintained its high disinfectant resistance after dispersal from the bottom and from the walls of the well. Combining all results highlights that <em>L. plantarum</em> biofilm structure and matrix, and physiological state and stress resistance of cells is strain dependent and strongly affected under flow conditions. It is concluded that consideration of effects of flow on biofilm formation is essential to better understand biofilm formation in different settings, including food processing environments.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100197"},"PeriodicalIF":6.8,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000224/pdfft?md5=b3688ae973cd96149f680e1a8e617792&pid=1-s2.0-S2590207524000224-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140645884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Farnesol repurposing for prevention and treatment of Acinetobacter baumannii biofilms","authors":"Li Tan,&nbsp;Rong Ma,&nbsp;Adam J. Katz,&nbsp;Nicole Levi","doi":"10.1016/j.bioflm.2024.100198","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100198","url":null,"abstract":"<div><p><em>Acinetobacter baumannii</em> has emerged as a multidrug-resistant (MDR) superbug by causing severe infections, with high mortality rates. The ability of <em>A. baumannii</em> to form biofilms significantly contributes to its persistence in diverse environmental and hospital settings. Here we report that farnesol, an FDA-approved commercial cosmetic and flavoring agent, demonstrates efficacy for both inhibition of biofilm formation, and disruption of established <em>A. baumannii</em> biofilms. Moreover, no resistance to farnesol was observed even after prolonged culture in the presence of sub-inhibitory farnesol doses. Farnesol combats <em>A. baumannii</em> biofilms by direct killing, while also facilitating biofilm detachment. Furthermore, farnesol was safe, and effective, for both prevention and treatment of <em>A. baumannii</em> biofilms in an <em>ex vivo</em> burned human skin model. Since current treatment options for <em>A. baumannii</em> biofilm infections were mainly counted on the combination therapy of last-resort antibiotics, and clearly non-sustainable due to robust MDR phenotype of <em>A. baumannii</em>, we propose that farnesol alone can be repurposed as a highly effective agent for both preventing and treating life-threating biofilm-associated infections of <em>A. baumannii</em> due to its proven safety, convenient topical delivery, and excellent efficiency, plus its superiority of evading resistance development.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100198"},"PeriodicalIF":6.8,"publicationDate":"2024-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000236/pdfft?md5=c7a4880ea218e256e65065845deb01c0&pid=1-s2.0-S2590207524000236-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140645852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interspecies interactions in dairy biofilms drive community structure and response against cleaning and disinfection","authors":"Faizan Ahmed Sadiq ,&nbsp;Koen De Reu ,&nbsp;Nan Yang ,&nbsp;Mette Burmølle ,&nbsp;Marc Heyndrickx","doi":"10.1016/j.bioflm.2024.100195","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100195","url":null,"abstract":"<div><p>Interspecies interactions within a biofilm community influence population dynamics and community structure, which in turn may affect the bacterial stress response to antimicrobials. This study was conducted to assess the impact of interactions between <em>Kocuria salsicia</em> and a three-species biofilm community (comprising <em>Stenotrophomonas rhizophila</em>, <em>Bacillus licheniformis</em>, and <em>Microbacterium lacticum</em>) on biofilm mass, the abundance of individual species, and their survival under a laboratory-scale cleaning and disinfection (C&amp;D) regime. The presence of <em>K. salsicia</em> enhanced the cell numbers of all three species in pairwise interactions. The outcomes derived from summing up pairwise interactions did not accurately predict the bacterial population dynamics within communities of more than two species. In four-species biofilms, we observed the dominance of <em>S. rhizophila</em> and <em>B. licheniformis</em>, alongside a concurrent reduction in the cell counts of <em>K. salsicia</em> and <em>M. lacticum</em>. This pattern suggests that the underlying interactions are not purely non-transitive; instead, a more complex interplay results in the dominance of specific species. We observed that bacterial spatial organization and matrix production in different mixed-species combinations affected survival in response to C&amp;D. Confocal microscopy analysis of spatial organization showed that <em>S. rhizophila</em> localized on the biofilm formed by <em>B. licheniformis</em> and <em>M. lacticum</em>, and <em>S. rhizophila</em> was more susceptible to C&amp;D. Matrix production in <em>B. licheniformis</em>, evidenced by alterations in biofilm mass and by scanning electron microscopy, demonstrated its protective role against C&amp;D, not only for this species itself, but also for neighbouring species. Our findings emphasise that various social interactions within a biofilm community not only affect bacterial population dynamics but also influence the biofilm community's response to C&amp;D stress.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100195"},"PeriodicalIF":6.8,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000200/pdfft?md5=c57f037c6f93b4332c14177591b53dfa&pid=1-s2.0-S2590207524000200-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140545959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ecology of Legionella pneumophila biofilms: The link between transcriptional activity and the biphasic cycle","authors":"Ana Barbosa ,&nbsp;Nuno F. Azevedo ,&nbsp;Darla M. Goeres ,&nbsp;Laura Cerqueira","doi":"10.1016/j.bioflm.2024.100196","DOIUrl":"10.1016/j.bioflm.2024.100196","url":null,"abstract":"<div><p>There has been considerable discussion regarding the environmental life cycle of <em>Legionella pneumophila</em> and its virulence potential in natural and man-made water systems. On the other hand, the bacterium's morphogenetic mechanisms within host cells (amoeba and macrophages) have been well documented and are linked to its ability to transition from a non-virulent, replicative state to an infectious, transmissive state.</p><p>Although the morphogenetic mechanisms associated with the formation and detachment of the <em>L. pneumophila</em> biofilm have also been described, the capacity of the bacteria to multiply extracellularly is not generally accepted. However, several studies have shown genetic pathways within the biofilm that resemble intracellular mechanisms. Understanding the functionality of <em>L. pneumophila</em> cells within a biofilm is fundamental for assessing the ecology and evaluating how the biofilm architecture influences <em>L. pneumophila</em> survival and persistence in water systems. This manuscript provides an overview of the biphasic cycle of <em>L. pneumophila</em> and its implications in associated intracellular mechanisms in amoeba. It also examines the molecular pathways and gene regulation involved in <em>L. pneumophila</em> biofilm formation and dissemination. A holistic analysis of the transcriptional activities in <em>L. pneumophila</em> biofilms is provided, combining the information of intracellular mechanisms in a comprehensive outline. Furthermore, this review discusses the techniques that can be used to study the morphogenetic states of the bacteria within biofilms, at the single cell and population levels.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100196"},"PeriodicalIF":6.8,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000212/pdfft?md5=4c29d291ff4ffb745c74e8ac2668b666&pid=1-s2.0-S2590207524000212-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140407195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Environmental magnesium ion affects global gene expression, motility, biofilm formation and virulence of Vibrio parahaemolyticus","authors":"Xue Li ,&nbsp;Xiaobai Zhang ,&nbsp;Miaomiao Zhang ,&nbsp;Xi Luo ,&nbsp;Tingting Zhang ,&nbsp;Xianjin Liu ,&nbsp;Renfei Lu ,&nbsp;Yiquan Zhang","doi":"10.1016/j.bioflm.2024.100194","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100194","url":null,"abstract":"<div><p><em>Vibrio parahaemolyticus</em> is widely distributed in marine ecosystems. Magnesium ion (Mg²⁺) is the second most abundant metal cation in seawater, and plays important roles in the growth and gene expression of <em>V</em>. <em>parahaemolyticus</em>, but lacks the detailed mechanisms. In this study, the RNA sequencing data demonstrated that a total of 1494 genes was significantly regulated by Mg²⁺. The majority of the genes associated with lateral flagella, exopolysaccharide, type III secretion system 2, type VI secretion system (T6SS) 1, T6SS2, and thermostable direct hemolysin were downregulated. A total of 18 genes that may be involved in c-di-GMP metabolism and more than 80 genes encoding putative regulators were also significantly and differentially expressed in response to Mg²⁺, indicating that the adaptation process to Mg²⁺ stress may be strictly regulated by complex regulatory networks. In addition, Mg²⁺ promoted the proliferative speed, swimming motility and cell adhesion of <em>V. parahaemolyticus</em>, but inhibited the swarming motility, biofilm formation, and c-di-GMP production. However, Mg²⁺ had no effect on the production of capsular polysaccharide and cytoxicity against HeLa cells. Therefore, Mg²⁺ had a comprehensive impact on the physiology and gene expression of <em>V. parahaemolyticus</em>.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100194"},"PeriodicalIF":6.8,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000194/pdfft?md5=b295f021312469d61bab120357e131d9&pid=1-s2.0-S2590207524000194-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140330579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elucidating the development of cooperative anode-biofilm-structures","authors":"Edina Klein ,&nbsp;René Wurst ,&nbsp;David Rehnlund ,&nbsp;Johannes Gescher","doi":"10.1016/j.bioflm.2024.100193","DOIUrl":"https://doi.org/10.1016/j.bioflm.2024.100193","url":null,"abstract":"<div><p>Microbial electrochemical systems are a highly versatile platform technology with a particular focus on the interplay of chemical and electrical energy conversion and offer immense potential for a sustainable bioeconomy. The industrial realization of this potential requires a critical focus on biofilm optimization if performance is to be controlled over a long period of time. Moreover, the aspect and influence of cooperativity has to be addressed as many applied anodic bioelectrochemical systems will most likely be operated with a diversity of interacting microbial species. Hence, the aim of this study was to analyze how interspecies dependence and cooperativity of a model community influence the development of anodic biofilms. To investigate biofilm activity in a spatially resolved manner, a microfluidic bioelectrochemical flow cell was developed that can be equipped with user-defined electrode materials and operates under laminar flow conditions. With this infrastructure, the development of single and co-culture biofilms of the two model organisms <em>Shewanella oneidensis</em> and <em>Geobacter sulfurreducens</em> on graphite electrodes was monitored by optical coherence tomography analysis. The interdependence in the co-culture biofilm was achieved by feeding the community with lactate, which is converted by <em>S. oneidensis</em> into acetate, which in turn serves as substrate for <em>G. sulfurreducens</em>. The results show that co-cultivation resulted in the formation of denser biofilms than in single culture. Moreover, we hypothesize that <em>S. oneidensis</em> in return utilizes the conductive biofilm matrix build by <em>G. sulfurreducens</em> for direct interspecies electron transfer (DIET) to the anode. FISH analysis revealed that the biofilms consisted of approximately two-thirds <em>G. sulfurreducens</em> cells, which most likely formed a conductive 3D network throughout the biofilm matrix, in which evenly distributed tubular <em>S. oneidensis</em> colonies were embedded without direct contact to the anode surface. Live/dead staining shows that the outermost biofilm contained almost exclusively dead cells (98 %), layers near the anode contained 45–56 % and the entire biofilm contained 82 % live cells. Our results exemplify how the architecture of the exoelectrogenic biofilm dynamically adapts to the respective process conditions.</p></div>","PeriodicalId":55844,"journal":{"name":"Biofilm","volume":"7 ","pages":"Article 100193"},"PeriodicalIF":6.8,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590207524000182/pdfft?md5=f7579a7a5626990c87322a47e6c0fbae&pid=1-s2.0-S2590207524000182-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140350389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}