Phytoplasmas are phloem-limited plant pathogenic bacteria causing diseases in many plant species. They are transmitted by Hemipteran insect species in a persistent-propagative manner. Phytoplasmas are wall-less, and their membrane proteins are involved in pathogen internalization into host cells. We focused on the immunodominant membrane protein (Imp) of Flavescence dorée phytoplasma (FDp), a grapevine quarantine pest and a major threat to European viticulture. Scaphoideus titanus is the main natural vector of FDp to grapevine, whereas Euscelidius variegatus is commonly used as laboratory vector. Previous works indicated that recombinant Imp of two FDp strains (FD-C and FD-D) selectively interact with gut proteins from vector species rather than those from non-vectors. Here, similar patterns of interacting insect gut proteins were obtained from both vector species, following pull-down with His-tagged FDp Imps. After identification of several targets, four S. titanus and five E. variegatus proteins interacting with Imp were further characterized by measuring expression in different insect tissues and in healthy vs. infected insects. Specific RNAi silencing of two of these vector genes, namely natterin and legumain, resulted in a significant reduction of phytoplasma multiplication in insects upon pathogen acquisition, compared to control insects. Natterin displays a DM9 domain and legumain possesses a signature of G protein receptor, supporting their involvement as FDp Imp receptors. Outcomes of this work are discussed with particular attention devoted to the gain of knowledge on host/pathogen interaction as well as to the potential impact on improvement phytoplasma disease management.
{"title":"Natterin-like and legumain insect gut proteins promote the multiplication of a vector-borne bacterial plant pathogen","authors":"Luciana Galetto , Giulia Lucetti , Luca Bucci , Francesca Canuto , Marika Rossi , Simona Abbà , Marta Vallino , Cecilia Parise , Sabrina Palmano , Marcello Manfredi , Domenico Bosco , Cristina Marzachì","doi":"10.1016/j.micres.2024.127984","DOIUrl":"10.1016/j.micres.2024.127984","url":null,"abstract":"<div><div>Phytoplasmas are phloem-limited plant pathogenic bacteria causing diseases in many plant species. They are transmitted by Hemipteran insect species in a persistent-propagative manner. Phytoplasmas are wall-less, and their membrane proteins are involved in pathogen internalization into host cells. We focused on the immunodominant membrane protein (Imp) of Flavescence dorée phytoplasma (FDp), a grapevine quarantine pest and a major threat to European viticulture. <em>Scaphoideus titanus</em> is the main natural vector of FDp to grapevine, whereas <em>Euscelidius variegatus</em> is commonly used as laboratory vector. Previous works indicated that recombinant Imp of two FDp strains (FD-C and FD-D) selectively interact with gut proteins from vector species rather than those from non-vectors. Here, similar patterns of interacting insect gut proteins were obtained from both vector species, following pull-down with His-tagged FDp Imps. After identification of several targets, four <em>S. titanus</em> and five <em>E. variegatus</em> proteins interacting with Imp were further characterized by measuring expression in different insect tissues and in healthy vs. infected insects. Specific RNAi silencing of two of these vector genes, namely natterin and legumain, resulted in a significant reduction of phytoplasma multiplication in insects upon pathogen acquisition, compared to control insects. Natterin displays a DM9 domain and legumain possesses a signature of G protein receptor, supporting their involvement as FDp Imp receptors. Outcomes of this work are discussed with particular attention devoted to the gain of knowledge on host/pathogen interaction as well as to the potential impact on improvement phytoplasma disease management.</div></div>","PeriodicalId":18564,"journal":{"name":"Microbiological research","volume":"291 ","pages":"Article 127984"},"PeriodicalIF":6.1,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-26DOI: 10.1016/j.micres.2024.127975
Lijia Guo , Jun Wang , You Zhou , Changcong Liang , Lei Liu , Yang Yang , Junsheng Huang , Laying Yang
The secreted isochorismatases derived from certain filamentous pathogens play vital roles in the infection of host plants by lowering salicylic acid (SA) levels and suppressing SA-mediated defense pathway. However, it remains unclear whether the fungus Fusarium oxysporum f. sp. cubense tropical race 4 (FocTR4), which causes vascular wilt in bananas, utilizes isochorismatases to modulate SA levels in the host and subvert the banana defense system for successful infection. In the current study, we selected and functionally characterized the foisc1 gene, one of 10 putative isochorismatase-encoding genes in FocTR4 that showed significant upregulation during early stages of infection. Deletion of foisc1 resulted in enhanced vegetative growth and conidiation, increased sensitivity to SA, reduced colonization within host plants, as well as impaired pathogenicity. Conversely, complementation restored phenotypes similar to those observed in the wild-type strain. Furthermore, deletion of foisc1 led to a notable rise in activities of defense-related enzymes such as catalase, peroxidase, and phenylalnine ammonialyase; along with an upregulated expression of several defense-related genes including PR genes and NPR1 genes within hosts' tissues. The non-secretory nature of Foisc1 protein was confirmed and its absence did not affect SA levels within host plants. Transcriptome analysis revealed that deletion of foisc1 resulted in decreased expression levels for numerous genes associated with pathogenicity including those involved in fusaric acid biosynthesis and effector genes as well as a catechol 1,2-dioxygenase gene essential for SA degradation; while increasing expression levels for numerous genes associated with hyphal growth and conidiation were observed instead. Therefore, our findings suggest that Foisc1 may influence hyphal growth, conidiation, sensitivity to SA, and pathogenicity of FocTR4 through modulation of various genes implicated in these processes. These findings provide valuable insights into the pathogenesis of FocTR4, and create a groundwork for the future development of innovative control strategies targeting vascular wilt disease of banana.
某些丝状病原体分泌的异构酶能降低水杨酸（SA）水平，抑制 SA 介导的防御途径，从而在寄主植物感染过程中发挥重要作用。然而，导致香蕉维管枯萎病的 Fusarium oxysporum f. sp. cubense tropical race 4（FocTR4）真菌是否利用异构酶调节宿主体内的 SA 水平并颠覆香蕉防御系统以成功感染，目前仍不清楚。在当前的研究中，我们选择了 foisc1 基因并对其进行了功能表征，该基因是 FocTR4 中 10 个假定的异构酶编码基因之一，在感染的早期阶段表现出显著的上调。缺失 foisc1 基因会导致无性生长和分生孢子能力增强、对 SA 的敏感性提高、宿主植物内的定殖能力降低以及致病性减弱。相反，互补则恢复了与野生型菌株相似的表型。此外，foisc1 的缺失导致过氧化氢酶、过氧化物酶和苯丙氨酸氨酰化酶等防御相关酶的活性显著上升；同时，宿主组织内的 PR 基因和 NPR1 基因等多个防御相关基因的表达也上调。Foisc1 蛋白的非分泌性得到了证实，它的缺失不会影响寄主植物体内的 SA 水平。转录组分析表明，缺失 Foisc1 会导致许多与致病性相关的基因表达水平下降，包括参与镰刀菌酸生物合成的基因、效应基因以及对 SA 降解至关重要的儿茶酚 1,2- 二氧酶基因；而与菌丝生长和分生相关的许多基因的表达水平反而升高。因此，我们的研究结果表明，Foisc1 可能会通过调节与 FocTR4 的生长、分生孢子、对 SA 的敏感性和致病性有关的各种基因来影响这些过程。这些发现为了解 FocTR4 的致病机理提供了有价值的见解，并为今后针对香蕉维管束枯萎病开发创新型防治策略奠定了基础。
{"title":"Foisc1 regulates growth, conidiation, sensitivity to salicylic acid, and pathogenicity of Fusarium oxysporum f. sp. cubense tropical race 4","authors":"Lijia Guo , Jun Wang , You Zhou , Changcong Liang , Lei Liu , Yang Yang , Junsheng Huang , Laying Yang","doi":"10.1016/j.micres.2024.127975","DOIUrl":"10.1016/j.micres.2024.127975","url":null,"abstract":"<div><div>The secreted isochorismatases derived from certain filamentous pathogens play vital roles in the infection of host plants by lowering salicylic acid (SA) levels and suppressing SA-mediated defense pathway. However, it remains unclear whether the fungus <em>Fusarium oxysporum</em> f. sp. <em>cubense</em> tropical race 4 (FocTR4), which causes vascular wilt in bananas, utilizes isochorismatases to modulate SA levels in the host and subvert the banana defense system for successful infection. In the current study, we selected and functionally characterized the <em>foisc1</em> gene, one of 10 putative isochorismatase-encoding genes in FocTR4 that showed significant upregulation during early stages of infection. Deletion of <em>foisc1</em> resulted in enhanced vegetative growth and conidiation, increased sensitivity to SA, reduced colonization within host plants, as well as impaired pathogenicity. Conversely, complementation restored phenotypes similar to those observed in the wild-type strain. Furthermore, deletion of <em>foisc1</em> led to a notable rise in activities of defense-related enzymes such as catalase, peroxidase, and phenylalnine ammonialyase; along with an upregulated expression of several defense-related genes including <em>PR</em> genes and <em>NPR1</em> genes within hosts' tissues. The non-secretory nature of Foisc1 protein was confirmed and its absence did not affect SA levels within host plants. Transcriptome analysis revealed that deletion of <em>foisc1</em> resulted in decreased expression levels for numerous genes associated with pathogenicity including those involved in fusaric acid biosynthesis and effector genes as well as a catechol 1,2-dioxygenase gene essential for SA degradation; while increasing expression levels for numerous genes associated with hyphal growth and conidiation were observed instead. Therefore, our findings suggest that Foisc1 may influence hyphal growth, conidiation, sensitivity to SA, and pathogenicity of FocTR4 through modulation of various genes implicated in these processes. These findings provide valuable insights into the pathogenesis of FocTR4, and create a groundwork for the future development of innovative control strategies targeting vascular wilt disease of banana.</div></div>","PeriodicalId":18564,"journal":{"name":"Microbiological research","volume":"291 ","pages":"Article 127975"},"PeriodicalIF":6.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-26DOI: 10.1016/j.micres.2024.127983
Qi Zhang
The plasmid-encoded mobile colistin resistance enzyme (MCR) is challenging the clinical efficacy of colistin as a last-resort antibiotic against multidrug-resistant bacteria. This transferase catalyzes the addition of positively charged phosphoethanolamine to lipid A, and its catalytic domain in the periplasm has been elucidated. To date, there are many works on the catalytic domain and function of this enzyme class. However, the roles of unreported soluble or inter-membrane domains remain undefined, which might cause an inaccurate or even incorrect understanding of substrate recognition and binding. In this review, MCR-1 is first compared and analyzed from the perspective of the full-length alpha-fold MCR-1. Specifically, some disputed issues, especially in its architecture and catalytic mechanism are discussed independently. Meanwhile, the structure-based insights into MCRs variants, their evolutions, and the balance between colistin-resistance and survival costs, are also critically analyzed. Importantly, by comparing it with the full-length MCR-1, several potential pockets for drug design have been re-identified. Finally, recent advancements in inhibitors targeting MCR-1 are also in-depth summarized. These details offer a new perspective on MCRs and serve as a valuable foundation for drug development.
{"title":"Structural insights into the advancements of mobile colistin resistance enzymes","authors":"Qi Zhang","doi":"10.1016/j.micres.2024.127983","DOIUrl":"10.1016/j.micres.2024.127983","url":null,"abstract":"<div><div>The plasmid-encoded mobile colistin resistance enzyme (MCR) is challenging the clinical efficacy of colistin as a last-resort antibiotic against multidrug-resistant bacteria. This transferase catalyzes the addition of positively charged phosphoethanolamine to lipid A, and its catalytic domain in the periplasm has been elucidated. To date, there are many works on the catalytic domain and function of this enzyme class. However, the roles of unreported soluble or inter-membrane domains remain undefined, which might cause an inaccurate or even incorrect understanding of substrate recognition and binding. In this review, MCR-1 is first compared and analyzed from the perspective of the full-length alpha-fold MCR-1. Specifically, some disputed issues, especially in its architecture and catalytic mechanism are discussed independently. Meanwhile, the structure-based insights into MCRs variants, their evolutions, and the balance between colistin-resistance and survival costs, are also critically analyzed. Importantly, by comparing it with the full-length MCR-1, several potential pockets for drug design have been re-identified. Finally, recent advancements in inhibitors targeting MCR-1 are also in-depth summarized. These details offer a new perspective on MCRs and serve as a valuable foundation for drug development.</div></div>","PeriodicalId":18564,"journal":{"name":"Microbiological research","volume":"291 ","pages":"Article 127983"},"PeriodicalIF":6.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-23DOI: 10.1016/j.micres.2024.127981
Franz Zehetbauer , Harald Berger , Florian Kastner , Joseph Strauss
Organisms are repeatedly exposed to fluctuating environmental and nutritional conditions. Transcriptional memory has been shown to be a mechanism to cope with these fluctuations because it increases the speed and the magnitude of the cellular response to a certain re-occurring condition and therefore optimizes adaptation and fitness in a given environment. We found that genes coding for sterigmatocystin (ST) production in Aspergillus nidulans are activated stronger when cells are repeatedly exposed to nutrient starvation, compared to cells that experience this condition for the first time. We studied possible underlying mechanisms and found that persistence of the transcription factor AflR, which can undergo activation-inactivation cycles, accounts for a large part of the memory. In addition, a chromatin-based mechanism through histone H3 lysine 4 dimethylation (H3K4me2) and extracellular metabolites produced during the first activation phase contribute to the memory process. Genome-wide transcriptome and chromatin analyses showed that only a few genes within the ST and other starvation-induced biosynthetic gene clusters gain the H3K4me2 mark during the 1st activation, but the majority of those which receive the mark also maintain it during the subsequent repression and re-activation phase. Combined with previous findings on chromatin-level regulation of biosynthetic gene clusters (BGCs) our recent data suggest that the H3K4me2 mark may contribute to the correct 3D organization of BGCs and that this is a prerequisite for activation and transcriptional memory.
{"title":"Transcriptional memory drives accelerated re-activation of several biosynthetic gene clusters in Aspergillus nidulans.","authors":"Franz Zehetbauer , Harald Berger , Florian Kastner , Joseph Strauss","doi":"10.1016/j.micres.2024.127981","DOIUrl":"10.1016/j.micres.2024.127981","url":null,"abstract":"<div><div>Organisms are repeatedly exposed to fluctuating environmental and nutritional conditions. Transcriptional memory has been shown to be a mechanism to cope with these fluctuations because it increases the speed and the magnitude of the cellular response to a certain re-occurring condition and therefore optimizes adaptation and fitness in a given environment. We found that genes coding for sterigmatocystin (ST) production in <em>Aspergillus nidulans</em> are activated stronger when cells are repeatedly exposed to nutrient starvation, compared to cells that experience this condition for the first time. We studied possible underlying mechanisms and found that persistence of the transcription factor AflR, which can undergo activation-inactivation cycles, accounts for a large part of the memory. In addition, a chromatin-based mechanism through histone H3 lysine 4 dimethylation (H3K4me2) and extracellular metabolites produced during the first activation phase contribute to the memory process. Genome-wide transcriptome and chromatin analyses showed that only a few genes within the ST and other starvation-induced biosynthetic gene clusters gain the H3K4me2 mark during the 1st activation, but the majority of those which receive the mark also maintain it during the subsequent repression and re-activation phase. Combined with previous findings on chromatin-level regulation of biosynthetic gene clusters (BGCs) our recent data suggest that the H3K4me2 mark may contribute to the correct 3D organization of BGCs and that this is a prerequisite for activation and transcriptional memory.</div></div>","PeriodicalId":18564,"journal":{"name":"Microbiological research","volume":"291 ","pages":"Article 127981"},"PeriodicalIF":6.1,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-22DOI: 10.1016/j.micres.2024.127982
Qipeng Cheng , Yanchu Cheung , Chen Xu , Edward Wai Chi Chan , Kin Fai Chan , Sheng Chen
Polymyxins, including colistin and polymyxin B, serve as crucial last-resort antibiotics for managing infections caused by carbapenem-resistant Enterobacterales (CRE). However, the rapid spread of the mobilized colistin resistance gene (mcr-1) challenged the efficacy of treatment by polymyxins. The mcr-1 gene encoded a transmembrane phosphoethanolamine (PEA) transferase enzyme, MCR-1. MCR-1 could catalyze the transfer of PEA moiety of phosphatidylethanolamine (PE) to the 1’ (or 4’)-phosphate group of the lipid A. Despite the determination of several structures of the soluble domain of MCR-1, the structural and biochemical mechanisms of integral MCR-1 remain less understood. In this study, we utilized an alanine scanning mutagenesis approach to systematically investigate the functional attributes of distinct regions within MCR-1. We identified fifteen critical residues that are indispensable for the enzymatic activity of MCR-1 and are pivotal for its ability to confer resistance to colistin. Furthermore, molecular docking of MCR-1 complexed with the phosphoethanolamine (PE) substrate revealed the presence of a channel-shaped cavity, a characteristic feature shared with other phosphoethanolamine transferases. Despite MCR-1 exhibiting a low sequence identity with both MCR homologues and other phosphoethanolamine (PEA) transferases, several conserved sites were identified, including Y97, M105, K333, H395, L477, and H478, suggesting a potentially shared catalytic mechanism among them for modifying LPS-lipid A. Overall, these findings provide a deep understanding of the catalytic mechanism of MCR-1 for colistin resistance. Moreover, these findings provide a robust structural and functional foundation, enabling the rational design of targeted inhibitors and restoring colistin activity against serious infections with carbapenem-resistant Enterobacterales (CRE).
{"title":"Overall mutational scanning unveils the essential active residues for the mechanistic action of MCR-1","authors":"Qipeng Cheng , Yanchu Cheung , Chen Xu , Edward Wai Chi Chan , Kin Fai Chan , Sheng Chen","doi":"10.1016/j.micres.2024.127982","DOIUrl":"10.1016/j.micres.2024.127982","url":null,"abstract":"<div><div>Polymyxins, including colistin and polymyxin B, serve as crucial last-resort antibiotics for managing infections caused by carbapenem-resistant Enterobacterales (CRE). However, the rapid spread of the mobilized colistin resistance gene (<em>mcr</em>-1) challenged the efficacy of treatment by polymyxins. The <em>mcr</em>-1 gene encoded a transmembrane phosphoethanolamine (PEA) transferase enzyme, MCR-1. MCR-1 could catalyze the transfer of PEA moiety of phosphatidylethanolamine (PE) to the 1’ (or 4’)-phosphate group of the lipid A. Despite the determination of several structures of the soluble domain of MCR-1, the structural and biochemical mechanisms of integral MCR-1 remain less understood. In this study, we utilized an alanine scanning mutagenesis approach to systematically investigate the functional attributes of distinct regions within MCR-1. We identified fifteen critical residues that are indispensable for the enzymatic activity of MCR-1 and are pivotal for its ability to confer resistance to colistin. Furthermore, molecular docking of MCR-1 complexed with the phosphoethanolamine (PE) substrate revealed the presence of a channel-shaped cavity, a characteristic feature shared with other phosphoethanolamine transferases. Despite MCR-1 exhibiting a low sequence identity with both MCR homologues and other phosphoethanolamine (PEA) transferases, several conserved sites were identified, including Y<sup>97</sup>, M<sup>105</sup>, K<sup>333</sup>, H<sup>395</sup>, L<sup>477</sup>, and H<sup>478</sup>, suggesting a potentially shared catalytic mechanism among them for modifying LPS-lipid A. Overall, these findings provide a deep understanding of the catalytic mechanism of MCR-1 for colistin resistance. Moreover, these findings provide a robust structural and functional foundation, enabling the rational design of targeted inhibitors and restoring colistin activity against serious infections with carbapenem-resistant Enterobacterales (CRE).</div></div>","PeriodicalId":18564,"journal":{"name":"Microbiological research","volume":"291 ","pages":"Article 127982"},"PeriodicalIF":6.1,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-22DOI: 10.1016/j.micres.2024.127980
Haotian Ma , Yuexia Ding , Jinju Peng , Yang Li , Ruixue Pan , Yuner Long , Yining Zhao , Rongxian Guo , Yi Ma
Listeria monocytogenes, a pathogenic bacterium causing zoonotic diseases, necessitates the urgent search for novel anti-Listeria monocytogenes drugs due to the continuous emergence of drug-resistant bacteria. In this study, we isolated and identified a bacteriocin-producing strain CM7–4 from seawater as Bacillus velezensis through 16S rRNA sequence analysis. Moreover, we successfully purified a novel bacteriocin named PCM7–4 from Bacillus velezensis CM7–4. The molecular weight of PCM7–4 was determined to be 40,228.99 Da. Notably, PCM7–4 exhibited broad-spectrum antibacterial activity against both Gram-positive and Gram-negative bacteria with a minimum inhibitory concentration (MIC) of 5.625 μg/mL against Listeria monocytogenes specifically. It demonstrated heat resistance and high stability within the pH range of 2–12 while being sensitive to proteinase K degradation without any observed hemolytic activity. Furthermore, SEM analysis revealed that PCM7–4 effectively inhibited biofilm formation and disrupted cell membranes in Listeria monocytogenes cells. Transcriptome analysis revealed that PCM7–4 exerts an impact on genes associated with crucial metabolic pathways, encompassing the biosynthesis of secondary metabolites, phosphotransferase systems (PTS), and starch/sucrose metabolism. These findings highlight the significant potential of bacteriocin PCM7–4 for the development of effective antimicrobial interventions targeting food-borne pathogenic bacteria.
{"title":"Identification and characterization of a novel bacteriocin PCM7-4 and its antimicrobial activity against Listeria monocytogenes","authors":"Haotian Ma , Yuexia Ding , Jinju Peng , Yang Li , Ruixue Pan , Yuner Long , Yining Zhao , Rongxian Guo , Yi Ma","doi":"10.1016/j.micres.2024.127980","DOIUrl":"10.1016/j.micres.2024.127980","url":null,"abstract":"<div><div><em>Listeria monocytogenes</em>, a pathogenic bacterium causing zoonotic diseases, necessitates the urgent search for novel anti-<em>Listeria monocytogenes</em> drugs due to the continuous emergence of drug-resistant bacteria. In this study, we isolated and identified a bacteriocin-producing strain CM7–4 from seawater as <em>Bacillus velezensis</em> through 16S rRNA sequence analysis. Moreover, we successfully purified a novel bacteriocin named PCM7–4 from <em>Bacillus velezensis</em> CM7–4. The molecular weight of PCM7–4 was determined to be 40,228.99 Da. Notably, PCM7–4 exhibited broad-spectrum antibacterial activity against both Gram-positive and Gram-negative bacteria with a minimum inhibitory concentration (MIC) of 5.625 μg/mL against <em>Listeria monocytogenes</em> specifically. It demonstrated heat resistance and high stability within the pH range of 2–12 while being sensitive to proteinase K degradation without any observed hemolytic activity. Furthermore, SEM analysis revealed that PCM7–4 effectively inhibited biofilm formation and disrupted cell membranes in <em>Listeria monocytogenes</em> cells. Transcriptome analysis revealed that PCM7–4 exerts an impact on genes associated with crucial metabolic pathways, encompassing the biosynthesis of secondary metabolites, phosphotransferase systems (PTS), and starch/sucrose metabolism. These findings highlight the significant potential of bacteriocin PCM7–4 for the development of effective antimicrobial interventions targeting food-borne pathogenic bacteria.</div></div>","PeriodicalId":18564,"journal":{"name":"Microbiological research","volume":"290 ","pages":"Article 127980"},"PeriodicalIF":6.1,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-21DOI: 10.1016/j.micres.2024.127976
Salina Patel , Lincoln Naik , Mousumi Das , Dev Kiran Nayak , Pramathesh Kumar Dandsena , Abtar Mishra , Ashish Kumar , Vijaya R. Dirisala , Amit Mishra , Surajit Das , Ramandeep Singh , Assirbad Behura , Rohan Dhiman
Mycobacterium tuberculosis (M. tb), the etiological agent of tuberculosis (TB), continues to be a major contributor to global mortality rates. To effectively combat this pandemic, TB control has to be enhanced in several areas, including point-of-care diagnostics, shorter and safer drug regimens, and preventative vaccination. The latest findings have highlighted autophagy as a host-defense mechanism that eradicates many invading bacteria, including M. tb. Thus, novel approaches like the stimulation of autophagy using various pharmaceutical drugs can be undertaken to deal with this noxious pathogen. The present study has been formulated to evaluate the anti-mycobacterial potential of Furamidine, a DNA minor groove binder (MGB). Initially, a non-cytotoxic concentration of Furamidine (10 µM) was used to assess its impact on the intracellular persistence of mycobacteria in differentiated THP-1 (dTHP-1) cells. Furamidine treatment compromised intracellular mycobacterial growth compared to control cells. Autophagy, a well-known host-defensive strategy, was investigated as a possible contributor to revealing the mechanism of action. Multiparametric approaches such as LC3-I to II conversion, protein level expression of different autophagic markers, and MDC staining were employed to study autophagic response that conclusively suggested the autophagy induction potential of Furamidine in dTHP-1 cells. Further, elevated LC3-II expression and increased autophagic vacuole accumulation under Baf-A1 treatment demonstrated the positive regulation of autophagic flux upon Furamidine treatment. Mechanistic investigations showed increased intracellular calcium (Ca2+) level expression, SIRT1, pAMPK, and FOXO3a activation upon its treatment. Inhibition of Ca2+ level expression suppressed Ca2+-mediated-FOXO3a level in Furamidine-treated cells. Furthermore, administering various inhibitors hampered the Furamidine-induced autophagy that impacted intracellular mycobacteria clearance. These results conclude that Furamidine triggered the Ca2+/pAMPK/SIRT1/FOXO3a pathway, causing less mycobacterial load in dTHP-1 cells.
{"title":"Furamidine-induced autophagy exerts an anti-mycobacterial effect in a SIRT1-pAMPK-FOXO3a-dependent manner by elevation of intracellular Ca2+ level expression","authors":"Salina Patel , Lincoln Naik , Mousumi Das , Dev Kiran Nayak , Pramathesh Kumar Dandsena , Abtar Mishra , Ashish Kumar , Vijaya R. Dirisala , Amit Mishra , Surajit Das , Ramandeep Singh , Assirbad Behura , Rohan Dhiman","doi":"10.1016/j.micres.2024.127976","DOIUrl":"10.1016/j.micres.2024.127976","url":null,"abstract":"<div><div><em>Mycobacterium tuberculosis</em> (<em>M. tb</em>), the etiological agent of tuberculosis (TB), continues to be a major contributor to global mortality rates. To effectively combat this pandemic, TB control has to be enhanced in several areas, including point-of-care diagnostics, shorter and safer drug regimens, and preventative vaccination. The latest findings have highlighted autophagy as a host-defense mechanism that eradicates many invading bacteria, including <em>M. tb.</em> Thus, novel approaches like the stimulation of autophagy using various pharmaceutical drugs can be undertaken to deal with this noxious pathogen. The present study has been formulated to evaluate the anti-mycobacterial potential of Furamidine, a DNA minor groove binder (MGB). Initially, a non-cytotoxic concentration of Furamidine (10 µM) was used to assess its impact on the intracellular persistence of mycobacteria in differentiated THP-1 (dTHP-1) cells. Furamidine treatment compromised intracellular mycobacterial growth compared to control cells. Autophagy, a well-known host-defensive strategy, was investigated as a possible contributor to revealing the mechanism of action. Multiparametric approaches such as LC3-I to II conversion, protein level expression of different autophagic markers, and MDC staining were employed to study autophagic response that conclusively suggested the autophagy induction potential of Furamidine in dTHP-1 cells. Further, elevated LC3-II expression and increased autophagic vacuole accumulation under Baf-A1 treatment demonstrated the positive regulation of autophagic flux upon Furamidine treatment. Mechanistic investigations showed increased intracellular calcium (Ca<sup>2+</sup>) level expression, SIRT1, pAMPK, and FOXO3a activation upon its treatment. Inhibition of Ca<sup>2+</sup> level expression suppressed Ca<sup>2+</sup>-mediated-FOXO3a level in Furamidine-treated cells. Furthermore, administering various inhibitors hampered the Furamidine-induced autophagy that impacted intracellular mycobacteria clearance. These results conclude that Furamidine triggered the Ca<sup>2+</sup>/pAMPK/SIRT1/FOXO3a pathway, causing less mycobacterial load in dTHP-1 cells.</div></div>","PeriodicalId":18564,"journal":{"name":"Microbiological research","volume":"290 ","pages":"Article 127976"},"PeriodicalIF":6.1,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.micres.2024.127977
Lijie Yang , Bingqian Yao , Shimin Zhang , Yuting Yang , Gang Wang , Hongbin Pan , Xiangfang Zeng , Shiyan Qiao
The Diqing Tibetan (TP) pig is an roughage tolerance breed that inhabits an area with the highest altitude distribution in the world and can be maintained on a diet containing 90 % forage material in confined production systems. Our results showed that TP pigs had a strong capability for high-efficiency utilization of arabinose and xylose. Metagenomic analysis revealed that the secretion of carbohydrate esterases was mainly undertaken by fecal strains of Microbacterium, Alistipes, Acinetobacter, and Faecalibacterium, while Microbacterium, Prevotella, Turicibacter, Lactobacillus, Clostridium, and Streptococcus were responsible for most of the secretion of glycoside hydrolases. Then, a brand new species, which was named Microbacterium sp. Qiao 01 was captured and appeared to have the highest fiber utilization ability in vitro, degrading 36.54 % of the neutral detergent fiber in corn stover. Our results provide strong evidence that efficient utilization of dietary fiber by TP pigs is due to the emergence of highly specialized microbial strategies in the gut. Microorganisms showed preferences and a clear division of labor in the degradation process of dietary fiber. This study has great practical significance for improving the utilization efficiency of livestock feed and alleviating the tension of food insecurity.
{"title":"Division mechanism of labor in Diqing Tibetan Pigs gut microbiota for dietary fiber efficiently utilization","authors":"Lijie Yang , Bingqian Yao , Shimin Zhang , Yuting Yang , Gang Wang , Hongbin Pan , Xiangfang Zeng , Shiyan Qiao","doi":"10.1016/j.micres.2024.127977","DOIUrl":"10.1016/j.micres.2024.127977","url":null,"abstract":"<div><div>The Diqing Tibetan (TP) pig is an roughage tolerance breed that inhabits an area with the highest altitude distribution in the world and can be maintained on a diet containing 90 % forage material in confined production systems. Our results showed that TP pigs had a strong capability for high-efficiency utilization of arabinose and xylose. Metagenomic analysis revealed that the secretion of carbohydrate esterases was mainly undertaken by fecal strains of <em>Microbacterium</em>, <em>Alistipes</em>, <em>Acinetobacter</em>, and <em>Faecalibacterium</em>, while <em>Microbacterium</em>, <em>Prevotella</em>, <em>Turicibacter</em>, <em>Lactobacillus</em>, <em>Clostridium</em>, and <em>Streptococcus</em> were responsible for most of the secretion of glycoside hydrolases. Then, a brand new species, which was named <em>Microbacterium sp. Qiao 01</em> was captured and appeared to have the highest fiber utilization ability <em>in vitro</em>, degrading 36.54 % of the neutral detergent fiber in corn stover. Our results provide strong evidence that efficient utilization of dietary fiber by TP pigs is due to the emergence of highly specialized microbial strategies in the gut. Microorganisms showed preferences and a clear division of labor in the degradation process of dietary fiber. This study has great practical significance for improving the utilization efficiency of livestock feed and alleviating the tension of food insecurity.</div></div>","PeriodicalId":18564,"journal":{"name":"Microbiological research","volume":"290 ","pages":"Article 127977"},"PeriodicalIF":6.1,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142693090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.micres.2024.127978
Toga Pangihotan Napitupulu
Bacterial-fungal interaction (BFI) is found ubiquitously and plays important roles in various environmental settings, thus being responsible for numerous biophysical and chemical processes in nature. In terms of BFI, the capacity of the bacterium to enhance the growth of fungal mycelia is an indication of the roles of the bacterium in mutualistic interaction, since increasing mycelial growth results in higher changes for fungal establishment. In this review, the interaction between mycelial growth-promoting bacterium (MGPB) and its fungal counterpart in agricultural settings and the promotion of mycelial growth as an outcome of mutual interactions in various environmental niches were evaluated. The beneficial relationships included endohyphal interaction, association of bacteria with mushrooms, bacteria-mycorrhizae symbiosis, and geomicrobiology. Furthermore, the mode of interaction between MGPB and their fungal counterparts was also explained. There are two fundamental modes of interaction involved, namely physical interaction and chemical interaction. The first involved endosymbiosis and bacterial attachment, while the latter comprised quorum sensing, volatile metabolites, enzymatic activity, and chemotaxis. Particularly, the growth stimulants secreted by the bacteria, which promote the growth of hyphae, are discussed thoroughly. Moreover, the chance of trade-off metabolites between fungi and their MGPBs as a consequence of mutualistic interaction will also be observed. Finally, the agricultural relevance of BFI, particularly the relation between fungi and MGPBs, will also be provided, including key technologies and future bioprospects for optimum application.
{"title":"Agricultural relevance of fungal mycelial growth-promoting bacteria: Mutual interaction and application","authors":"Toga Pangihotan Napitupulu","doi":"10.1016/j.micres.2024.127978","DOIUrl":"10.1016/j.micres.2024.127978","url":null,"abstract":"<div><div>Bacterial-fungal interaction (BFI) is found ubiquitously and plays important roles in various environmental settings, thus being responsible for numerous biophysical and chemical processes in nature. In terms of BFI, the capacity of the bacterium to enhance the growth of fungal mycelia is an indication of the roles of the bacterium in mutualistic interaction, since increasing mycelial growth results in higher changes for fungal establishment. In this review, the interaction between mycelial growth-promoting bacterium (MGPB) and its fungal counterpart in agricultural settings and the promotion of mycelial growth as an outcome of mutual interactions in various environmental niches were evaluated. The beneficial relationships included endohyphal interaction, association of bacteria with mushrooms, bacteria-mycorrhizae symbiosis, and geomicrobiology. Furthermore, the mode of interaction between MGPB and their fungal counterparts was also explained. There are two fundamental modes of interaction involved, namely physical interaction and chemical interaction. The first involved endosymbiosis and bacterial attachment, while the latter comprised quorum sensing, volatile metabolites, enzymatic activity, and chemotaxis. Particularly, the growth stimulants secreted by the bacteria, which promote the growth of hyphae, are discussed thoroughly. Moreover, the chance of trade-off metabolites between fungi and their MGPBs as a consequence of mutualistic interaction will also be observed. Finally, the agricultural relevance of BFI, particularly the relation between fungi and MGPBs, will also be provided, including key technologies and future bioprospects for optimum application.</div></div>","PeriodicalId":18564,"journal":{"name":"Microbiological research","volume":"290 ","pages":"Article 127978"},"PeriodicalIF":6.1,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.micres.2024.127965
Patricia Arias-Orozco , Rubén Cebrián , Anne de Jong , Oscar P. Kuipers
Synechococsins represent a diverse group of class II lanthipeptides from the prochlorosin family, produced by the marine picocyanobacterium Synechococcus. A single strain can produce multiple SyncA peptides through modification by SyncM, a bifunctional lanthipeptide synthetase. Despite the prevalence of these lanthipeptides in nature, their biological functions remain elusive, even for the most studied group, Prochlorococcus MIT9313. This study investigated the transcriptomic response of the marine SyncA-producing strain Synechococcus sp. RS9116 to the characterized and purified SyncA6 peptide from Synechococcus sp. MITS9509. Intriguingly, the analysis of gene expression revealed a strong down-regulation of genes that encode putative ribosomally produced antimicrobial peptides, such as coculture-responsive genes (CCRG-2) and microcin-C-like bacteriocins. This study suggests a potential biological role for synechococsins as interspecific gene modulators, improving the fitness of the producing strain in a competitive and resource-limited environment.
{"title":"Synechococsins: Lanthipeptides acting as defensive signals to disarm offensive competitors?","authors":"Patricia Arias-Orozco , Rubén Cebrián , Anne de Jong , Oscar P. Kuipers","doi":"10.1016/j.micres.2024.127965","DOIUrl":"10.1016/j.micres.2024.127965","url":null,"abstract":"<div><div>Synechococsins represent a diverse group of class II lanthipeptides from the prochlorosin family, produced by the marine picocyanobacterium <em>Synechococcus.</em> A single strain can produce multiple SyncA peptides through modification by SyncM, a bifunctional lanthipeptide synthetase. Despite the prevalence of these lanthipeptides in nature, their biological functions remain elusive, even for the most studied group, <em>Prochlorococcus</em> MIT9313. This study investigated the transcriptomic response of the marine SyncA-producing strain <em>Synechococcus</em> sp. RS9116 to the characterized and purified SyncA6 peptide from <em>Synechococcus</em> sp. MITS9509. Intriguingly, the analysis of gene expression revealed a strong down-regulation of genes that encode putative ribosomally produced antimicrobial peptides, such as coculture-responsive genes (CCRG-2) and microcin-C-like bacteriocins. This study suggests a potential biological role for synechococsins as interspecific gene modulators, improving the fitness of the producing strain in a competitive and resource-limited environment.</div></div>","PeriodicalId":18564,"journal":{"name":"Microbiological research","volume":"291 ","pages":"Article 127965"},"PeriodicalIF":6.1,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号