Pub Date : 2026-06-01Epub Date: 2026-01-02DOI: 10.1016/j.engmic.2025.100259
Peiyuan Feng , Moli Sang , Wei Zhang
Aspertetranones are a unique class of marine fungal meroditerpenoids characterized by a highly oxygenated, linear 6/6/6/6 tetracyclic core fused to an α-pyrone scaffold. Although the pathway of aspertetranone biosynthesis in Aspergillus ochraceopetaliformis has been partially elucidated, the full potential of these compounds remains untapped. The structural diversity and enzyme promiscuity of tailoring reactions offer unexplored opportunities for the generation of bioactive derivatives through combinatorial biosynthesis. In this study, we identified the atn biosynthetic gene cluster responsible for aspertetranone production in deep-sea-derived Aspergillus versicolor ADS-F20. Through the systematic heterologous expression of 12 key genes in Aspergillus oryzae, the full pathway reconstitution and targeted biosynthesis of 17 metabolites were achieved, thus expanding the known chemical space of meroterpenoids. Notably, bioactivity screening identified compound 6 as having potent antibacterial and antifungal activities against Vibrio vulnificus ATCC 27562 (MIC = 4.50 μg/mL) and Phytophthora nicotianae (MIC = 9.01 μg/mL). Compound 11 demonstrated broad-spectrum anticancer and cytotoxic effects against the K-562, MCF7, and PATU8988T cell lines. This study underscores the power of pathway reprogramming and catalytic network engineering as versatile strategies for expanding the structural and functional diversity of biosynthetic pathway components.
{"title":"Pathway reprogramming and catalytic network engineering for the production of bioactive aspertetranones from deep-sea Aspergillus versicolor ADS-F20","authors":"Peiyuan Feng , Moli Sang , Wei Zhang","doi":"10.1016/j.engmic.2025.100259","DOIUrl":"10.1016/j.engmic.2025.100259","url":null,"abstract":"<div><div>Aspertetranones are a unique class of marine fungal meroditerpenoids characterized by a highly oxygenated, linear 6/6/6/6 tetracyclic core fused to an α-pyrone scaffold. Although the pathway of aspertetranone biosynthesis in <em>Aspergillus ochraceopetaliformis</em> has been partially elucidated, the full potential of these compounds remains untapped. The structural diversity and enzyme promiscuity of tailoring reactions offer unexplored opportunities for the generation of bioactive derivatives through combinatorial biosynthesis. In this study, we identified the <em>atn</em> biosynthetic gene cluster responsible for aspertetranone production in deep-sea-derived <em>Aspergillus versicolor</em> ADS-F20. Through the systematic heterologous expression of 12 key genes in <em>Aspergillus oryzae</em>, the full pathway reconstitution and targeted biosynthesis of 17 metabolites were achieved, thus expanding the known chemical space of meroterpenoids. Notably, bioactivity screening identified compound <strong>6</strong> as having potent antibacterial and antifungal activities against <em>Vibrio vulnificus</em> ATCC 27562 (MIC = 4.50 μg/mL) and <em>Phytophthora nicotianae</em> (MIC = 9.01 μg/mL). Compound <strong>11</strong> demonstrated broad-spectrum anticancer and cytotoxic effects against the K-562, MCF7, and PATU8988T cell lines. This study underscores the power of pathway reprogramming and catalytic network engineering as versatile strategies for expanding the structural and functional diversity of biosynthetic pathway components.</div></div>","PeriodicalId":100478,"journal":{"name":"Engineering Microbiology","volume":"6 2","pages":"Article 100259"},"PeriodicalIF":0.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-21DOI: 10.1016/j.engmic.2026.100260
Yuke Cen , Hang Xiao , Jingwen Jia , Jiajia Mou , Haoyang Li , Jialiang Wang , Yaling Yi , Minghan Li , Zhiqiang Liu , Yuguo Zheng
Gene knockdown is a pivotal genetic manipulation technique, particularly when targeting lethal genes or genes involved in product synthesis pathways, where complete gene knockout is not a viable option. This approach is particularly valuable in multinucleate species, such as Fusarium fujikuroi, where generating homogeneous gene knockouts is notoriously difficult. To address these limitations, we first screened a set of repression domains, and then leveraged the optimal candidates to construct a CRISPR/dCas9-mediated knockdown platform for F. fujikuroi. By targeting erg9, which encodes squalene synthase, the first committed enzyme in the mevalonate pathway for ergosterol biosynthesis, we successfully diverted a portion of the metabolic flux from sterol production to gibberellic acid (GA) biosynthesis. This strategy minimizes carbon loss to competing pathways while retaining phenotypically normal growth. Additionally, CRISPR/dCas9-mediated knockdown of the dehydrogenase gene des enhanced GA4 production by 2.62-fold and eliminated the intermediate GA7, generating a GA3+4-producing strain and fine-tuning its metabolic profile. Using our CRISPRi system, we achieved a 70–89 % reduction in erg9 mRNA levels and a 67– 84 % reduction in des mRNA levels. Our findings establish a tailored CRISPRi platform for effective gene repression in F. fujikuroi.
{"title":"Development of a CRISPRi system in Fusarium fujikuroi and its application in gibberellic acid production","authors":"Yuke Cen , Hang Xiao , Jingwen Jia , Jiajia Mou , Haoyang Li , Jialiang Wang , Yaling Yi , Minghan Li , Zhiqiang Liu , Yuguo Zheng","doi":"10.1016/j.engmic.2026.100260","DOIUrl":"10.1016/j.engmic.2026.100260","url":null,"abstract":"<div><div>Gene knockdown is a pivotal genetic manipulation technique, particularly when targeting lethal genes or genes involved in product synthesis pathways, where complete gene knockout is not a viable option. This approach is particularly valuable in multinucleate species, such as <em>Fusarium fujikuroi</em>, where generating homogeneous gene knockouts is notoriously difficult. To address these limitations, we first screened a set of repression domains, and then leveraged the optimal candidates to construct a CRISPR/dCas9-mediated knockdown platform for <em>F. fujikuroi</em>. By targeting <em>erg9</em>, which encodes squalene synthase, the first committed enzyme in the mevalonate pathway for ergosterol biosynthesis, we successfully diverted a portion of the metabolic flux from sterol production to gibberellic acid (GA) biosynthesis. This strategy minimizes carbon loss to competing pathways while retaining phenotypically normal growth. Additionally, CRISPR/dCas9-mediated knockdown of the dehydrogenase gene <em>des</em> enhanced GA<sub>4</sub> production by 2.62-fold and eliminated the intermediate GA<sub>7</sub>, generating a GA<sub>3+4</sub>-producing strain and fine-tuning its metabolic profile. Using our CRISPRi system, we achieved a 70–89 % reduction in <em>erg9</em> mRNA levels and a 67– 84 % reduction in <em>des</em> mRNA levels. Our findings establish a tailored CRISPRi platform for effective gene repression in <em>F. fujikuroi</em>.</div></div>","PeriodicalId":100478,"journal":{"name":"Engineering Microbiology","volume":"6 2","pages":"Article 100260"},"PeriodicalIF":0.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146174024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hachiman systems provide innate antiphage immunity across prokaryotic domains. The system encodes a HamA nuclease and a HamB helicase both of which exhibit great diversity in sequence. Phylogenetic analyses of HamA and HamB proteins revealed similar phylogenetic trees for both proteins, falling into three major types. Close examination of one of the subclades identified a distinct subfamily in which most of these Hachiman systems stands alone, however, Hachiman in the Streptococcus genus is combined with PezAT, a distinct pneumococcal epsilon zeta toxin-antitoxin system, yielding the Pez-Ham system. Investigation of a S. thermophilus Pez-Ham system revealed that only the Hachiman system is required for mediating antiphage defence. Biochemical characterization of encoded proteins, i.e., HamA or HamB individually or in protein complex revealed that the HamA nuclease is inactive alone, but upon the formation of heterologous dimer with HamB, the resulting protein complex effectively cleaves DNAs of various forms with a broad specificity (5′-CNNNG-3′), and the nuclease activity is greatly facilitated by ATP-binding in HamB and to a less degree by ATP hydrolysis. Genetic investigations further showed, while the Pez system did not function in antiphage immunity in Escherichia coli, the system repressed the expression of Hachiman, and thereby balancing the trade-off between the fitness cost and the effectiveness of antiphage defence.
{"title":"Modulation of Hachiman defence by a type II toxin-antitoxin system via balancing trade-off between the fitness cost and antiphage activity","authors":"Xuhui Tian, Ruyi Zheng, Xin Li, Suping Jiang, Fang Wang, Yulong Shen, Qunxin She","doi":"10.1016/j.engmic.2025.100254","DOIUrl":"10.1016/j.engmic.2025.100254","url":null,"abstract":"<div><div>Hachiman systems provide innate antiphage immunity across prokaryotic domains. The system encodes a HamA nuclease and a HamB helicase both of which exhibit great diversity in sequence. Phylogenetic analyses of HamA and HamB proteins revealed similar phylogenetic trees for both proteins, falling into three major types. Close examination of one of the subclades identified a distinct subfamily in which most of these Hachiman systems stands alone, however, Hachiman in the <em>Streptococcus</em> genus is combined with PezAT, a distinct pneumococcal epsilon zeta toxin-antitoxin system, yielding the Pez-Ham system. Investigation of a <em>S. thermophilus</em> Pez-Ham system revealed that only the Hachiman system is required for mediating antiphage defence. Biochemical characterization of encoded proteins, i.e., HamA or HamB individually or in protein complex revealed that the HamA nuclease is inactive alone, but upon the formation of heterologous dimer with HamB, the resulting protein complex effectively cleaves DNAs of various forms with a broad specificity (5′-CNNNG-3′), and the nuclease activity is greatly facilitated by ATP-binding in HamB and to a less degree by ATP hydrolysis. Genetic investigations further showed, while the Pez system did not function in antiphage immunity in <em>Escherichia coli</em>, the system repressed the expression of Hachiman, and thereby balancing the trade-off between the fitness cost and the effectiveness of antiphage defence.</div></div>","PeriodicalId":100478,"journal":{"name":"Engineering Microbiology","volume":"6 1","pages":"Article 100254"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-20DOI: 10.1016/j.engmic.2025.100255
Jie Qiao , Luxuan Wu , Xiaoru Ma , Anni Li , Yannan Tian , Hailong Lin , Dongsheng Guo , Xiujuan Li
Polyethylene (PE) is one of the most widely used plastics worldwide and is valued for its versatility, durability, and cost-effectiveness. However, the chemical stability of PE combined with its widespread use makes it a persistent environmental pollutant that contributes to the accumulation of plastic waste in terrestrial and marine ecosystems. The escalating issue of plastic pollution has underscored the importance of developing sustainable solutions, of which PE biodegradation has emerged as a promising avenue for mitigating the environmental burden of recalcitrant polyolefins. This review systematically summarizes the recent advances in the biodegradation and bioconversion of PE, focusing on methods for evaluating degradation efficiency, the mechanisms by which microorganisms and enzymes contribute to PE degradation, and the microbial and enzymatic resources identified to date. In addition, we discuss physicochemical strategies that enhance degradation efficiency and their integration with biological approaches, as well as the potential applications of emerging biotechnological tools in PE degradation. The integration of cutting-edge biotechnological tools such as synthetic biology and machine learning with traditional biodegradation methods holds great potential for accelerating PE degradation rates and achieving more sustainable plastic waste management.
{"title":"Advances in polyethylene biodegradation and bioconversion: Microbial, enzymatic, and biotechnological insights","authors":"Jie Qiao , Luxuan Wu , Xiaoru Ma , Anni Li , Yannan Tian , Hailong Lin , Dongsheng Guo , Xiujuan Li","doi":"10.1016/j.engmic.2025.100255","DOIUrl":"10.1016/j.engmic.2025.100255","url":null,"abstract":"<div><div>Polyethylene (PE) is one of the most widely used plastics worldwide and is valued for its versatility, durability, and cost-effectiveness. However, the chemical stability of PE combined with its widespread use makes it a persistent environmental pollutant that contributes to the accumulation of plastic waste in terrestrial and marine ecosystems. The escalating issue of plastic pollution has underscored the importance of developing sustainable solutions, of which PE biodegradation has emerged as a promising avenue for mitigating the environmental burden of recalcitrant polyolefins. This review systematically summarizes the recent advances in the biodegradation and bioconversion of PE, focusing on methods for evaluating degradation efficiency, the mechanisms by which microorganisms and enzymes contribute to PE degradation, and the microbial and enzymatic resources identified to date. In addition, we discuss physicochemical strategies that enhance degradation efficiency and their integration with biological approaches, as well as the potential applications of emerging biotechnological tools in PE degradation. The integration of cutting-edge biotechnological tools such as synthetic biology and machine learning with traditional biodegradation methods holds great potential for accelerating PE degradation rates and achieving more sustainable plastic waste management.</div></div>","PeriodicalId":100478,"journal":{"name":"Engineering Microbiology","volume":"6 1","pages":"Article 100255"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-18DOI: 10.1016/j.engmic.2025.100251
Daiki Kojima , Masahiro Ito
Following the Fukushima Daiichi nuclear power plant accident, radioactive cesium was released into the environment, prompting intensified efforts to identify cesium-resistant microorganisms. During these studies, we isolated a cesium-resistant Escherichia coli strain, designated ZX-1, which exhibits remarkable tolerance to cesium concentrations exceeding 700 mM. As no prior reports of cesium-resistant E. coli exist, this finding suggests the presence of a previously unrecognized resistance mechanism. This study aims to elucidate the molecular basis of cesium resistance in ZX-1.
RNA-seq analysis comparing ZX-1 with its parental strain, the commercial E. coli Mach1™, revealed constitutive upregulation of the guanidinium exporter gene gdx in ZX-1. Reanalysis of the whole-genome sequence identified a 20-bp deletion upstream of the gdx open reading frame, likely disrupting formation of the guanidinium riboswitch P2 loop and resulting in constitutive gdx expression.
To evaluate gdx function, the gene was cloned into the expression vector pBAD24 and expressed in E. coli. The resulting gdx-expressing strain exhibited even greater cesium resistance than ZX-1. Functional assays demonstrated that this strain mediates not only guanidinium/H⁺ antiport activity but also Cs⁺/H⁺ antiport activity. Cesium resistance was further enhanced in the presence of guanidinium, consistent with riboswitch-mediated induction of gdx.
Collectively, these findings provide evidence for a novel cesium efflux mechanism in E. coli and uncover an unexpected role of the guanidinium exporter Gdx in cesium export. These insights may facilitate the discovery of additional cesium-resistant microorganisms and broaden the potential for future applications.
{"title":"Gdx mediates low-affinity Cs⁺/H⁺ antiport and confers cesium resistance in Escherichia coli","authors":"Daiki Kojima , Masahiro Ito","doi":"10.1016/j.engmic.2025.100251","DOIUrl":"10.1016/j.engmic.2025.100251","url":null,"abstract":"<div><div>Following the Fukushima Daiichi nuclear power plant accident, radioactive cesium was released into the environment, prompting intensified efforts to identify cesium-resistant microorganisms. During these studies, we isolated a cesium-resistant <em>Escherichia coli</em> strain, designated ZX-1, which exhibits remarkable tolerance to cesium concentrations exceeding 700 mM. As no prior reports of cesium-resistant <em>E. coli</em> exist, this finding suggests the presence of a previously unrecognized resistance mechanism. This study aims to elucidate the molecular basis of cesium resistance in ZX-1.</div><div>RNA-seq analysis comparing ZX-1 with its parental strain, the commercial <em>E. coli</em> Mach1™, revealed constitutive upregulation of the guanidinium exporter gene <em>gdx</em> in ZX-1. Reanalysis of the whole-genome sequence identified a 20-bp deletion upstream of the <em>gdx</em> open reading frame, likely disrupting formation of the guanidinium riboswitch P2 loop and resulting in constitutive <em>gdx</em> expression.</div><div>To evaluate <em>gdx</em> function, the gene was cloned into the expression vector pBAD24 and expressed in <em>E. coli</em>. The resulting <em>gdx</em>-expressing strain exhibited even greater cesium resistance than ZX-1. Functional assays demonstrated that this strain mediates not only guanidinium/H⁺ antiport activity but also Cs⁺/H⁺ antiport activity. Cesium resistance was further enhanced in the presence of guanidinium, consistent with riboswitch-mediated induction of <em>gdx</em>.</div><div>Collectively, these findings provide evidence for a novel cesium efflux mechanism in <em>E. coli</em> and uncover an unexpected role of the guanidinium exporter Gdx in cesium export. These insights may facilitate the discovery of additional cesium-resistant microorganisms and broaden the potential for future applications.</div></div>","PeriodicalId":100478,"journal":{"name":"Engineering Microbiology","volume":"6 1","pages":"Article 100251"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-18DOI: 10.1016/j.engmic.2025.100252
Pan Huang , Meiqi Du , Yanqiu Liu , Zhenhao Han , Qian Wan , Fuming Liang , Wenyuan Han
The interaction and co-evolution between human gut bacteria and their phages shape the dynamic gut microbiome, exerting a significant impact on human health. However, the underlying mechanisms are largely unexplored. In particular, a bacteria-phage interaction model of the Bacteroidota phylum and the Microviridae phages is lacking, limiting our understanding of their ecological roles in human gut. In this study, we isolated a Bacteroidota-infecting Microviridae phage φHBP1 from human feces. Infection of its host Bacteroides fragilis with φHBP1 drives multiple genomic structural variations, which are correlated with host resistance to φHBP1. In turn, our phage evolution assay in B. fragilis H1 obtained φHBP1 mutants that carry mutations within the capsid and pilot proteins and can reinfect the resistant bacterial population. Together, our findings provide novel insights into an antagonistic co-evolution mechanism between gut phage and bacteria, and hold important implications for diversifying phages through evolution to target resistant bacteria in phage therapy.
{"title":"Phase variation in Bacteroides fragilis governs susceptibility to a microvirus and drives its evolution","authors":"Pan Huang , Meiqi Du , Yanqiu Liu , Zhenhao Han , Qian Wan , Fuming Liang , Wenyuan Han","doi":"10.1016/j.engmic.2025.100252","DOIUrl":"10.1016/j.engmic.2025.100252","url":null,"abstract":"<div><div>The interaction and co-evolution between human gut bacteria and their phages shape the dynamic gut microbiome, exerting a significant impact on human health. However, the underlying mechanisms are largely unexplored. In particular, a bacteria-phage interaction model of the Bacteroidota phylum and the <em>Microviridae</em> phages is lacking, limiting our understanding of their ecological roles in human gut. In this study, we isolated a Bacteroidota-infecting <em>Microviridae</em> phage φHBP1 from human feces. Infection of its host <em>Bacteroides fragilis</em> with φHBP1 drives multiple genomic structural variations, which are correlated with host resistance to φHBP1. In turn, our phage evolution assay in <em>B. fragilis</em> H1 obtained φHBP1 mutants that carry mutations within the capsid and pilot proteins and can reinfect the resistant bacterial population. Together, our findings provide novel insights into an antagonistic co-evolution mechanism between gut phage and bacteria, and hold important implications for diversifying phages through evolution to target resistant bacteria in phage therapy.</div></div>","PeriodicalId":100478,"journal":{"name":"Engineering Microbiology","volume":"6 1","pages":"Article 100252"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-19DOI: 10.1016/j.engmic.2025.100249
Yiqing Zhang , Yinfeng Wei , Yuxin Huang , Chenyu Wang , Tao Wang , Yujiao Wang , Yingxuan Qi , Guannan Liu
Yeast cell mating is regulated by the transcription factor Ste12, which activates the transcription of mating genes by binding to pheromone response elements (PREs) in their promoters. PREs vary in number and position among different promoters. However, the effect of PRE organization on Ste12-promoter interactions and the possible downstream transcription of mating genes remains to be fully understood. In this study, we analyzed yeast pheromone-induced gene expression using RNA-seq transcription profiling. We retrieved the promoters of the significantly upregulated genes, focusing on the occurrence and arrangement of PREs. PPRM1, which carries three adjacent consensus PREs, was selected as a model for investigating the relative contribution of each PRE to promoter activity through single-base mutation or deletion. We then evaluated the impact of different PRE organizations on pheromone-induced expression by altering their orientations and copy numbers. Subsequently, we proposed a model to explain the mechanism of transcriptional regulation of pheromone-inducible genes, in which the organization of PREs modulates promoter activity by influencing Ste12 oligomerization. This study paves the way for deciphering the transcriptional mechanisms of eukaryotic regulatory systems.
{"title":"Analysis of the PRE configuration reveals the constraints in Ste12 oligomerization in mediating pheromone-inducible transcription in Saccharomyces cerevisiae","authors":"Yiqing Zhang , Yinfeng Wei , Yuxin Huang , Chenyu Wang , Tao Wang , Yujiao Wang , Yingxuan Qi , Guannan Liu","doi":"10.1016/j.engmic.2025.100249","DOIUrl":"10.1016/j.engmic.2025.100249","url":null,"abstract":"<div><div>Yeast cell mating is regulated by the transcription factor Ste12, which activates the transcription of mating genes by binding to pheromone response elements (PREs) in their promoters. PREs vary in number and position among different promoters. However, the effect of PRE organization on Ste12-promoter interactions and the possible downstream transcription of mating genes remains to be fully understood. In this study, we analyzed yeast pheromone-induced gene expression using RNA-seq transcription profiling. We retrieved the promoters of the significantly upregulated genes, focusing on the occurrence and arrangement of PREs. <em>PPRM1</em>, which carries three adjacent consensus PREs, was selected as a model for investigating the relative contribution of each PRE to promoter activity through single-base mutation or deletion. We then evaluated the impact of different PRE organizations on pheromone-induced expression by altering their orientations and copy numbers. Subsequently, we proposed a model to explain the mechanism of transcriptional regulation of pheromone-inducible genes, in which the organization of PREs modulates promoter activity by influencing Ste12 oligomerization. This study paves the way for deciphering the transcriptional mechanisms of eukaryotic regulatory systems.</div></div>","PeriodicalId":100478,"journal":{"name":"Engineering Microbiology","volume":"6 1","pages":"Article 100249"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147448768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-18DOI: 10.1016/j.engmic.2025.100250
Raju Ahmmed , Andrew Paff , Lingyan Kong , Songnan Li , Darrell W. Cockburn , Libo Tan
Resistant starch is a dietary fiber that escapes digestion in the small intestine and undergoes fermentation by gut microbiota in the colon, producing beneficial short-chain fatty acids (SCFAs). Among the various types of resistant starch, resistant starch type 5 (RS5) has gained significant attention due to its unique and stable structural and functional properties. RS5 is a self-assembled V-type inclusion complex formed when amylose helices encapsulate guest molecules. This formation occurs through non-covalent interactions after the native starch structure is disrupted, and a guest compound is introduced. This structure provides enhanced resistance to enzymatic digestion, slows fermentation, and facilitates targeted release of bioactive molecules, making it effective in modulating gut health. RS5 promotes the proliferation of beneficial gut microbiota while suppressing pathogenic species, leading to increased SCFAs production, mostly butyrate, acetate, and propionate, which maintain intestinal integrity, reduces inflammation, and supports metabolic regulation. RS5 also contributes to preventing and managing chronic diseases such as obesity, type 2 diabetes, and colorectal cancer. While prior research has focused on its preparation methods and physicochemical characteristics, the influence of RS5 on gut microbiota and host health remains inadequately explored. This review summarizes the formation, classification, and structural diversity of RS5 complexes and how these factors influence digestibility and fermentation kinetics. Furthermore, it explores how RS5 modulates the composition and metabolic activity of the gut microbiota, enhancing SCFAs production. By comparing RS5 with other RS types, this review highlights its superior prebiotic potential and supports RS5-based functional food development for improving gut and metabolic health, targeting gut microecology.
{"title":"Effect of resistant starch type 5 on gut health through modulating gut microbiota","authors":"Raju Ahmmed , Andrew Paff , Lingyan Kong , Songnan Li , Darrell W. Cockburn , Libo Tan","doi":"10.1016/j.engmic.2025.100250","DOIUrl":"10.1016/j.engmic.2025.100250","url":null,"abstract":"<div><div>Resistant starch is a dietary fiber that escapes digestion in the small intestine and undergoes fermentation by gut microbiota in the colon, producing beneficial short-chain fatty acids (SCFAs). Among the various types of resistant starch, resistant starch type 5 (RS5) has gained significant attention due to its unique and stable structural and functional properties. RS5 is a self-assembled V-type inclusion complex formed when amylose helices encapsulate guest molecules. This formation occurs through non-covalent interactions after the native starch structure is disrupted, and a guest compound is introduced. This structure provides enhanced resistance to enzymatic digestion, slows fermentation, and facilitates targeted release of bioactive molecules, making it effective in modulating gut health. RS5 promotes the proliferation of beneficial gut microbiota while suppressing pathogenic species, leading to increased SCFAs production, mostly butyrate, acetate, and propionate, which maintain intestinal integrity, reduces inflammation, and supports metabolic regulation. RS5 also contributes to preventing and managing chronic diseases such as obesity, type 2 diabetes, and colorectal cancer. While prior research has focused on its preparation methods and physicochemical characteristics, the influence of RS5 on gut microbiota and host health remains inadequately explored. This review summarizes the formation, classification, and structural diversity of RS5 complexes and how these factors influence digestibility and fermentation kinetics. Furthermore, it explores how RS5 modulates the composition and metabolic activity of the gut microbiota, enhancing SCFAs production. By comparing RS5 with other RS types, this review highlights its superior prebiotic potential and supports RS5-based functional food development for improving gut and metabolic health, targeting gut microecology.</div></div>","PeriodicalId":100478,"journal":{"name":"Engineering Microbiology","volume":"6 1","pages":"Article 100250"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-19DOI: 10.1016/j.engmic.2025.100253
Jiaoyang Song , Ming Hu , Min Zhao , Shengqing Luo , Yibao Chen , Yuqing Liu , Yingjun Li
Bacillus subtilis is widely used in industrial fermentation and probiotic applications; however, phage contamination poses a substantial economic threat. To address this, we isolated three phages (PJNB030, PJNB031, and PJNB032) from a contaminated B. subtilis fermentation broth and characterized their biological properties. Phenotypic analyses indicated broad pH stability (pH 4–10), variable thermal tolerance, and differential UV sensitivity. Replication kinetics revealed latent periods of 10–20 min and burst sizes ranging from 50 to 73 PFU/cell. Genomic sequencing identified linear dsDNA genomes (64–165 kb) with GC content ranging from 33.5 to 47.4%. Phylogenomic and comparative genomic analyses revealed that these phages were located on distinct branches. Deletion of pgcA (which encodes α-phosphoglucomutase) rendered cells completely resistant to PJNB031 and PJNB032, whereas it reduced PJNB030 infectivity (plaque formation efficiency) by approximately six orders of magnitude. Adsorption assays confirmed that the binding of PJNB031 and PJNB032 to ΔpgcA mutants was abolished, whereas PJNB030 retained partial adsorption capacity. In conclusion, this study identified wall teichoic acid as the primary receptor for these phages and established pgcA deletion as an effective strategy for engineering phage-resistant B. subtilis strains. Our findings provide critical insights into the mitigation of phage contamination in industrial bioprocesses.
{"title":"Characterization of Bacillus subtilis phages PJNB030, PJNB031, and PJNB032 reveals wall teichoic acid as a key receptor determinant","authors":"Jiaoyang Song , Ming Hu , Min Zhao , Shengqing Luo , Yibao Chen , Yuqing Liu , Yingjun Li","doi":"10.1016/j.engmic.2025.100253","DOIUrl":"10.1016/j.engmic.2025.100253","url":null,"abstract":"<div><div><em>Bacillus subtilis</em> is widely used in industrial fermentation and probiotic applications; however, phage contamination poses a substantial economic threat. To address this, we isolated three phages (PJNB030, PJNB031, and PJNB032) from a contaminated <em>B. subtilis</em> fermentation broth and characterized their biological properties. Phenotypic analyses indicated broad pH stability (pH 4–10), variable thermal tolerance, and differential UV sensitivity. Replication kinetics revealed latent periods of 10–20 min and burst sizes ranging from 50 to 73 PFU/cell. Genomic sequencing identified linear dsDNA genomes (64–165 kb) with GC content ranging from 33.5 to 47.4%. Phylogenomic and comparative genomic analyses revealed that these phages were located on distinct branches. Deletion of <em>pgcA</em> (which encodes α-phosphoglucomutase) rendered cells completely resistant to PJNB031 and PJNB032, whereas it reduced PJNB030 infectivity (plaque formation efficiency) by approximately six orders of magnitude. Adsorption assays confirmed that the binding of PJNB031 and PJNB032 to Δ<em>pgcA</em> mutants was abolished, whereas PJNB030 retained partial adsorption capacity. In conclusion, this study identified wall teichoic acid as the primary receptor for these phages and established <em>pgcA</em> deletion as an effective strategy for engineering phage-resistant <em>B. subtilis</em> strains. Our findings provide critical insights into the mitigation of phage contamination in industrial bioprocesses.</div></div>","PeriodicalId":100478,"journal":{"name":"Engineering Microbiology","volume":"6 1","pages":"Article 100253"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-24DOI: 10.1016/j.engmic.2025.100258
Jin Wang , Xueyan Liu , Longqian Zhao , Yue Zhang , Meng Wang
Genetically encoded biosensors provide powerful tools for coupling desired phenotypes to detectable outputs and have been extensively developed to detect a wide range of natural and unnatural products. When integrated with diverse high-throughput screening (HTS) approaches, these biosensors enable efficient product-driven screening across various throughputs, thereby expediting the engineering and optimization of microbial cell factories to produce various target compounds. For effective HTS of microbial cell factories, biosensors need to possess certain crucial characteristics. The performance features of biosensors significantly influence their application potential in HTS and can be precisely engineered through synthetic biology strategies. Furthermore, to ensure biosensor-driven HTS, additional engineering and optimizations of the biosensors are often required to increase the success rate and reduce false positives in the screening process. This review discusses the essential features of genetically encoded biosensors designed for HTS and then summarizes the latest advances in biosensor engineering for HTS purposes via synthetic biology strategies. Following this, the challenges and optimization of biosensors to adapt to different HTS processes are also discussed and exemplified. Finally, the key concerns and research prospects of developing biosensors for HTS applications are highlighted. Overall, this review provides comprehensive guidance on the engineering of genetically encoded biosensors and their applications in HTS for developing microbial cell factories to produce diverse target compounds.
{"title":"Genetically encoded biosensors enabled high-throughput screening of microbial cell factories","authors":"Jin Wang , Xueyan Liu , Longqian Zhao , Yue Zhang , Meng Wang","doi":"10.1016/j.engmic.2025.100258","DOIUrl":"10.1016/j.engmic.2025.100258","url":null,"abstract":"<div><div>Genetically encoded biosensors provide powerful tools for coupling desired phenotypes to detectable outputs and have been extensively developed to detect a wide range of natural and unnatural products. When integrated with diverse high-throughput screening (HTS) approaches, these biosensors enable efficient product-driven screening across various throughputs, thereby expediting the engineering and optimization of microbial cell factories to produce various target compounds. For effective HTS of microbial cell factories, biosensors need to possess certain crucial characteristics. The performance features of biosensors significantly influence their application potential in HTS and can be precisely engineered through synthetic biology strategies. Furthermore, to ensure biosensor-driven HTS, additional engineering and optimizations of the biosensors are often required to increase the success rate and reduce false positives in the screening process. This review discusses the essential features of genetically encoded biosensors designed for HTS and then summarizes the latest advances in biosensor engineering for HTS purposes via synthetic biology strategies. Following this, the challenges and optimization of biosensors to adapt to different HTS processes are also discussed and exemplified. Finally, the key concerns and research prospects of developing biosensors for HTS applications are highlighted. Overall, this review provides comprehensive guidance on the engineering of genetically encoded biosensors and their applications in HTS for developing microbial cell factories to produce diverse target compounds.</div></div>","PeriodicalId":100478,"journal":{"name":"Engineering Microbiology","volume":"6 1","pages":"Article 100258"},"PeriodicalIF":0.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}