Pub Date : 2024-03-19eCollection Date: 2024-03-01DOI: 10.1002/mlf2.12111
Dawn E Holmes, Trevor L Woodard, Jessica A Smith, Florin Musat, Derek R Lovley
Anaerobic microbial corrosion of iron-containing metals causes extensive economic damage. Some microbes are capable of direct metal-to-microbe electron transfer (electrobiocorrosion), but the prevalence of electrobiocorrosion among diverse methanogens and acetogens is poorly understood because of a lack of tools for their genetic manipulation. Previous studies have suggested that respiration with 316L stainless steel as the electron donor is indicative of electrobiocorrosion, because, unlike pure Fe0, 316L stainless steel does not abiotically generate H2 as an intermediary electron carrier. Here, we report that all of the methanogens (Methanosarcina vacuolata, Methanothrix soehngenii, and Methanobacterium strain IM1) and acetogens (Sporomusa ovata and Clostridium ljungdahlii) evaluated respired with pure Fe0 as the electron donor, but only M. vacuolata, Mx. soehngenii, and S. ovata were capable of stainless steel electrobiocorrosion. The electrobiocorrosive methanogens required acetate as an additional energy source in order to produce methane from stainless steel. Cocultures of S. ovata and Mx. soehngenii demonstrated how acetogens can provide acetate to methanogens during corrosion. Not only was Methanobacterium strain IM1 not capable of electrobiocorrosion, but it also did not accept electrons from Geobacter metallireducens, an effective electron-donating partner for direct interspecies electron transfer to all methanogens that can directly accept electrons from Fe0. The finding that M. vacuolata, Mx. soehngenii, and S. ovata are capable of electrobiocorrosion, despite a lack of the outer-surface c-type cytochromes previously found to be important in other electrobiocorrosive microbes, demonstrates that there are multiple microbial strategies for making electrical contact with Fe0.
{"title":"Electrobiocorrosion by microbes without outer-surface cytochromes.","authors":"Dawn E Holmes, Trevor L Woodard, Jessica A Smith, Florin Musat, Derek R Lovley","doi":"10.1002/mlf2.12111","DOIUrl":"10.1002/mlf2.12111","url":null,"abstract":"<p><p>Anaerobic microbial corrosion of iron-containing metals causes extensive economic damage. Some microbes are capable of direct metal-to-microbe electron transfer (electrobiocorrosion), but the prevalence of electrobiocorrosion among diverse methanogens and acetogens is poorly understood because of a lack of tools for their genetic manipulation. Previous studies have suggested that respiration with 316L stainless steel as the electron donor is indicative of electrobiocorrosion, because, unlike pure Fe<sup>0</sup>, 316L stainless steel does not abiotically generate H<sub>2</sub> as an intermediary electron carrier. Here, we report that all of the methanogens (<i>Methanosarcina vacuolata, Methanothrix soehngenii</i>, and <i>Methanobacterium</i> strain IM1) and acetogens (<i>Sporomusa ovata</i> and <i>Clostridium ljungdahlii</i>) evaluated respired with pure Fe<sup>0</sup> as the electron donor, but only <i>M. vacuolata, Mx. soehngenii</i>, and <i>S. ovata</i> were capable of stainless steel electrobiocorrosion. The electrobiocorrosive methanogens required acetate as an additional energy source in order to produce methane from stainless steel. Cocultures of <i>S. ovata</i> and <i>Mx. soehngenii</i> demonstrated how acetogens can provide acetate to methanogens during corrosion. Not only was <i>Methanobacterium</i> strain IM1 not capable of electrobiocorrosion, but it also did not accept electrons from <i>Geobacter metallireducens</i>, an effective electron-donating partner for direct interspecies electron transfer to all methanogens that can directly accept electrons from Fe<sup>0</sup>. The finding that <i>M. vacuolata, Mx. soehngenii</i>, and <i>S. ovata</i> are capable of electrobiocorrosion, despite a lack of the outer-surface <i>c</i>-type cytochromes previously found to be important in other electrobiocorrosive microbes, demonstrates that there are multiple microbial strategies for making electrical contact with Fe<sup>0</sup>.</p>","PeriodicalId":94145,"journal":{"name":"mLife","volume":"3 1","pages":"110-118"},"PeriodicalIF":0.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11139208/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141201208","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}
Weilong Shang, Zhen Hu, Mengyang Li, Yuting Wang, Yifan Rao, Li Tan, Juan Chen, Xiaonan Huang, Lu Liu, He Liu, Zuwen Guo, Huagang Peng, Yi Yang, Qiwen Hu, Shu Li, Xiaomei Hu, Jiao Zou, Xiancai Rao
Focal and systemic infections are serious threats to human health. Preclinical models enable the development of new drugs and therapeutic regimens. In vivo, animal bioluminescence (BL) imaging has been used with bacterial reporter strains to evaluate antimicrobial treatment effects. However, high‐sensitivity bioluminescent systems are required because of the limited tissue penetration and low brightness of the BL signals of existing approaches. Here, we report that NanoLuc (Nluc) showed better performance than LuxCDABE in bacteria. However, the retention rate of plasmid constructs in bacteria was low. To construct stable Staphylococcus aureus reporter strains, a partner protein enolase (Eno) was identified by screening of S. aureus strain USA300 for fusion expression of Nluc‐based luciferases, including Nluc, Teluc, and Antares2. Different substrates, such as hydrofurimazine (HFZ), furimazine (FUR), and diphenylterazine (DTZ), were used to optimize a stable reporter strain/substrate pair for BL imaging. S. aureus USA300/Eno‐Antares2/HFZ produced the highest number of photons of orange‐red light in vitro and enabled sensitive BL tracking of S. aureus in vivo, with sensitivities of approximately 10 CFU from mouse skin and 750 CFU from mouse kidneys. USA300/Eno‐Antares2/HFZ was a powerful combination based on the longitudinal evaluation of the therapeutic efficacy of antibiotics. The optimized S. aureus Eno‐Antares2/HFZ pair provides a technological advancement for the in vivo evaluation of antimicrobial treatment.
{"title":"Optimizing a high‐sensitivity NanoLuc‐based bioluminescence system for in vivo evaluation of antimicrobial treatment","authors":"Weilong Shang, Zhen Hu, Mengyang Li, Yuting Wang, Yifan Rao, Li Tan, Juan Chen, Xiaonan Huang, Lu Liu, He Liu, Zuwen Guo, Huagang Peng, Yi Yang, Qiwen Hu, Shu Li, Xiaomei Hu, Jiao Zou, Xiancai Rao","doi":"10.1002/mlf2.12091","DOIUrl":"https://doi.org/10.1002/mlf2.12091","url":null,"abstract":"Focal and systemic infections are serious threats to human health. Preclinical models enable the development of new drugs and therapeutic regimens. In vivo, animal bioluminescence (BL) imaging has been used with bacterial reporter strains to evaluate antimicrobial treatment effects. However, high‐sensitivity bioluminescent systems are required because of the limited tissue penetration and low brightness of the BL signals of existing approaches. Here, we report that NanoLuc (Nluc) showed better performance than LuxCDABE in bacteria. However, the retention rate of plasmid constructs in bacteria was low. To construct stable Staphylococcus aureus reporter strains, a partner protein enolase (Eno) was identified by screening of S. aureus strain USA300 for fusion expression of Nluc‐based luciferases, including Nluc, Teluc, and Antares2. Different substrates, such as hydrofurimazine (HFZ), furimazine (FUR), and diphenylterazine (DTZ), were used to optimize a stable reporter strain/substrate pair for BL imaging. S. aureus USA300/Eno‐Antares2/HFZ produced the highest number of photons of orange‐red light in vitro and enabled sensitive BL tracking of S. aureus in vivo, with sensitivities of approximately 10 CFU from mouse skin and 750 CFU from mouse kidneys. USA300/Eno‐Antares2/HFZ was a powerful combination based on the longitudinal evaluation of the therapeutic efficacy of antibiotics. The optimized S. aureus Eno‐Antares2/HFZ pair provides a technological advancement for the in vivo evaluation of antimicrobial treatment.","PeriodicalId":94145,"journal":{"name":"mLife","volume":"21 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138955258","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}
Dylan Baker, Casey Godwin, Muhtamim Khanam, Ashley M. Burtner, Gregory J. Dick, Vincent J. Denef
Freshwater harmful algal blooms are often dominated by Microcystis, a phylogenetically cohesive group of cyanobacteria marked by extensive genetic and physiological diversity. We have previously shown that this genetic diversity and the presence of a microbiome of heterotrophic bacteria influences competitive interactions with eukaryotic phytoplankton. In this study, we sought to explain these observations by characterizing Monod equation parameters for resource usage (maximum growth rate μmax, half‐saturation value for growth Ks, and quota) as a function of N and P levels for four strains (NIES‐843, PCC 9701, PCC 7806 [WT], and PCC 7806 ΔmcyB) in presence and absence of a microbiome derived from Microcystis isolated from Lake Erie. Results indicated limited differences in maximum growth rates but more pronounced differences in half‐saturation values among Microcystis strains. The largest impact of the microbiome was reducing the minimal nitrogen concentration sustaining growth and reducing half saturation values, with variable results depending on the Microcystis strain. Microcystis strains also differed from each other in their N and P quotas and the extent to which microbiome presence affected them. Our data highlight the importance of the microbiome in altering Microcystis‐intrinsic traits, strain competitive hierarchies, and thus bloom dynamics. As quota, μmax, and Ks are commonly used in models for harmful algal blooms, our data suggest that model improvement may be possible by incorporating genotype dependencies of resource‐use parameters.
{"title":"Variation in resource competition traits among Microcystis strains is affected by their microbiomes","authors":"Dylan Baker, Casey Godwin, Muhtamim Khanam, Ashley M. Burtner, Gregory J. Dick, Vincent J. Denef","doi":"10.1002/mlf2.12094","DOIUrl":"https://doi.org/10.1002/mlf2.12094","url":null,"abstract":"Freshwater harmful algal blooms are often dominated by Microcystis, a phylogenetically cohesive group of cyanobacteria marked by extensive genetic and physiological diversity. We have previously shown that this genetic diversity and the presence of a microbiome of heterotrophic bacteria influences competitive interactions with eukaryotic phytoplankton. In this study, we sought to explain these observations by characterizing Monod equation parameters for resource usage (maximum growth rate μmax, half‐saturation value for growth Ks, and quota) as a function of N and P levels for four strains (NIES‐843, PCC 9701, PCC 7806 [WT], and PCC 7806 ΔmcyB) in presence and absence of a microbiome derived from Microcystis isolated from Lake Erie. Results indicated limited differences in maximum growth rates but more pronounced differences in half‐saturation values among Microcystis strains. The largest impact of the microbiome was reducing the minimal nitrogen concentration sustaining growth and reducing half saturation values, with variable results depending on the Microcystis strain. Microcystis strains also differed from each other in their N and P quotas and the extent to which microbiome presence affected them. Our data highlight the importance of the microbiome in altering Microcystis‐intrinsic traits, strain competitive hierarchies, and thus bloom dynamics. As quota, μmax, and Ks are commonly used in models for harmful algal blooms, our data suggest that model improvement may be possible by incorporating genotype dependencies of resource‐use parameters.","PeriodicalId":94145,"journal":{"name":"mLife","volume":"125 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138965133","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 : 2023-12-18eCollection Date: 2023-12-01DOI: 10.1002/mlf2.12096
Rongrong Zhang, Yajia Huang, Mei Li, Lei Wang, Bing Li, Aiguo Xia, Ye Li, Shuai Yang, Fan Jin
Synthetic biology relies on the screening and quantification of genetic components to assemble sophisticated gene circuits with specific functions. Microscopy is a powerful tool for characterizing complex cellular phenotypes with increasing spatial and temporal resolution to library screening of genetic elements. Microscopy-based assays are powerful tools for characterizing cellular phenotypes with spatial and temporal resolution and can be applied to large-scale samples for library screening of genetic elements. However, strategies for high-throughput microscopy experiments remain limited. Here, we present a high-throughput, microscopy-based platform that can simultaneously complete the preparation of an 8 × 12-well agarose pad plate, allowing for the screening of 96 independent strains or experimental conditions in a single experiment. Using this platform, we screened a library of natural intrinsic promoters from Pseudomonas aeruginosa and identified a small subset of robust promoters that drives stable levels of gene expression under varying growth conditions. Additionally, the platform allowed for single-cell measurement of genetic elements over time, enabling the identification of complex and dynamic phenotypes to map genotype in high throughput. We expected that the platform could be employed to accelerate the identification and characterization of genetic elements in various biological systems, as well as to understand the relationship between cellular phenotypes and internal states, including genotypes and gene expression programs.
{"title":"High-throughput, microscopy-based screening and quantification of genetic elements.","authors":"Rongrong Zhang, Yajia Huang, Mei Li, Lei Wang, Bing Li, Aiguo Xia, Ye Li, Shuai Yang, Fan Jin","doi":"10.1002/mlf2.12096","DOIUrl":"10.1002/mlf2.12096","url":null,"abstract":"<p><p>Synthetic biology relies on the screening and quantification of genetic components to assemble sophisticated gene circuits with specific functions. Microscopy is a powerful tool for characterizing complex cellular phenotypes with increasing spatial and temporal resolution to library screening of genetic elements. Microscopy-based assays are powerful tools for characterizing cellular phenotypes with spatial and temporal resolution and can be applied to large-scale samples for library screening of genetic elements. However, strategies for high-throughput microscopy experiments remain limited. Here, we present a high-throughput, microscopy-based platform that can simultaneously complete the preparation of an 8 × 12-well agarose pad plate, allowing for the screening of 96 independent strains or experimental conditions in a single experiment. Using this platform, we screened a library of natural intrinsic promoters from <i>Pseudomonas aeruginosa</i> and identified a small subset of robust promoters that drives stable levels of gene expression under varying growth conditions. Additionally, the platform allowed for single-cell measurement of genetic elements over time, enabling the identification of complex and dynamic phenotypes to map genotype in high throughput. We expected that the platform could be employed to accelerate the identification and characterization of genetic elements in various biological systems, as well as to understand the relationship between cellular phenotypes and internal states, including genotypes and gene expression programs.</p>","PeriodicalId":94145,"journal":{"name":"mLife","volume":"2 4","pages":"450-461"},"PeriodicalIF":5.4,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10989126/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141181760","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}
Microplastics and nanoplastics are emerging pollutants that substantially influence biological element cycling in natural ecosystems. Plastics are also prevalent in sewage, and they accumulate in waste‐activated sludge (WAS). However, the impacts of plastics on the methanogenic digestion of WAS and the underpinning microbiome remain underexplored, particularly during long‐term operation. In this study, we found that short‐term exposure to individual microplastics and nanoplastics (polyethylene, polyvinyl chloride, polystyrene, and polylactic acid) at a low concentration (10 particles/g sludge) slightly enhanced methanogenesis by 2.1%−9.0%, whereas higher levels (30−200 particles/g sludge) suppressed methanogenesis by 15.2%−30.1%. Notably, the coexistence of multiple plastics, particularly at low concentrations, showed synergistic suppression of methanogenesis. Unexpectedly, methanogenesis activity completely recovered after long‐term exposure to plastics, despite obvious suppression of methanogenesis by initial plastic exposure. The inhibition of methanogenesis by plastics could be attributed to the stimulated generation of reactive oxygen species. The stress induced by plastics dramatically decreased the relative abundance of methanogens but showed marginal influence on putative hydrolytic and fermentation populations. Nonetheless, the digestion sludge microbiome exhibited resilience and functional redundancy, contributing to the recovery of methanogenesis during the long‐term operation of digesters. Plastics also increased the complexity, modularity, and negative interaction ratios of digestion sludge microbiome networks, but their influence on community assembly varied. Interestingly, a unique plastisphere was observed, the networks and assembly of which were distinct from the sludge microbiome. Collectively, the comprehensive evaluation of the influence of microplastics and nanoplastics on methanogenic digestion, together with the novel ecological insights, contribute to better understanding and manipulating this engineered ecosystem in the face of increasing plastic pollution.
微塑料和纳米塑料是新出现的污染物，对自然生态系统中的生物元素循环产生了重大影响。塑料也普遍存在于污水中，并在废物活性污泥（WAS）中积累。然而，塑料对 WAS 的产甲烷消化和基础微生物群的影响，尤其是在长期运行过程中的影响，仍未得到充分探索。在这项研究中，我们发现短期暴露于低浓度（10 颗粒/克污泥）的单个微塑料和纳米塑料（聚乙烯、聚氯乙烯、聚苯乙烯和聚乳酸）会略微促进甲烷生成，增幅为 2.1%-9.0%，而较高浓度（30-200 颗粒/克污泥）则会抑制甲烷生成，增幅为 15.2%-30.1%。值得注意的是，多种塑料共存，特别是在低浓度下，会协同抑制甲烷的生成。意想不到的是，尽管最初接触塑料明显抑制了甲烷生成，但长期接触塑料后，甲烷生成活性完全恢复。塑料对甲烷生成的抑制作用可能是由于刺激了活性氧的生成。塑料诱导的压力大大降低了甲烷菌的相对丰度，但对推定水解和发酵菌群的影响微乎其微。不过，消化污泥微生物群表现出了恢复能力和功能冗余，有助于在消化器长期运行期间恢复甲烷生成。塑料还增加了消化污泥微生物组网络的复杂性、模块化和负交互比，但它们对群落组装的影响各不相同。有趣的是，研究人员观察到了一种独特的塑球，其网络和组合与污泥微生物组截然不同。总之，全面评估微塑料和纳米塑料对产甲烷消化的影响，以及新颖的生态学见解，有助于在塑料污染日益严重的情况下更好地理解和操纵这一工程生态系统。
{"title":"Resilience and functional redundancy of methanogenic digestion microbiome safeguard recovery of methanogenesis activity under the stress induced by microplastics","authors":"Jinting Liu, Guofang Xu, Siyan Zhao, Jianzhong He","doi":"10.1002/mlf2.12090","DOIUrl":"https://doi.org/10.1002/mlf2.12090","url":null,"abstract":"Microplastics and nanoplastics are emerging pollutants that substantially influence biological element cycling in natural ecosystems. Plastics are also prevalent in sewage, and they accumulate in waste‐activated sludge (WAS). However, the impacts of plastics on the methanogenic digestion of WAS and the underpinning microbiome remain underexplored, particularly during long‐term operation. In this study, we found that short‐term exposure to individual microplastics and nanoplastics (polyethylene, polyvinyl chloride, polystyrene, and polylactic acid) at a low concentration (10 particles/g sludge) slightly enhanced methanogenesis by 2.1%−9.0%, whereas higher levels (30−200 particles/g sludge) suppressed methanogenesis by 15.2%−30.1%. Notably, the coexistence of multiple plastics, particularly at low concentrations, showed synergistic suppression of methanogenesis. Unexpectedly, methanogenesis activity completely recovered after long‐term exposure to plastics, despite obvious suppression of methanogenesis by initial plastic exposure. The inhibition of methanogenesis by plastics could be attributed to the stimulated generation of reactive oxygen species. The stress induced by plastics dramatically decreased the relative abundance of methanogens but showed marginal influence on putative hydrolytic and fermentation populations. Nonetheless, the digestion sludge microbiome exhibited resilience and functional redundancy, contributing to the recovery of methanogenesis during the long‐term operation of digesters. Plastics also increased the complexity, modularity, and negative interaction ratios of digestion sludge microbiome networks, but their influence on community assembly varied. Interestingly, a unique plastisphere was observed, the networks and assembly of which were distinct from the sludge microbiome. Collectively, the comprehensive evaluation of the influence of microplastics and nanoplastics on methanogenic digestion, together with the novel ecological insights, contribute to better understanding and manipulating this engineered ecosystem in the face of increasing plastic pollution.","PeriodicalId":94145,"journal":{"name":"mLife","volume":"100 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138998161","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}
Whether prokaryotes, and other microorganisms, form distinct clusters that can be recognized as species remains an issue of paramount theoretical as well as practical consequence in identifying, regulating, and communicating about these organisms. In the past decade, comparisons of thousands of genomes of isolates and hundreds of metagenomes have shown that prokaryotic diversity may be predominantly organized in such sequence‐discrete clusters, albeit organisms of intermediate relatedness between the identified clusters are also frequently found. Accumulating evidence suggests, however, that the latter “intermediate” organisms show enough ecological and/or functional distinctiveness to be considered different species. Notably, the area of discontinuity between clusters often—but not always—appears to be around 85%–95% genome‐average nucleotide identity, consistently among different taxa. More recent studies have revealed remarkably similar diversity patterns for viruses and microbial eukaryotes as well. This high consistency across taxa implies a specific mechanistic process that underlies the maintenance of the clusters. The underlying mechanism may be a substantial reduction in the efficiency of homologous recombination, which mediates (successful) horizontal gene transfer, around 95% nucleotide identity. Deviations from the 95% threshold (e.g., species showing lower intraspecies diversity) may be caused by ecological differentiation that imposes barriers to otherwise frequent gene transfer. While this hypothesis that clusters are driven by ecological differentiation coupled to recombination frequency (i.e., higher recombination within vs. between groups) is appealing, the supporting evidence remains anecdotal. The data needed to rigorously test the hypothesis toward advancing the species concept are also outlined.
{"title":"Sequence‐discrete species for prokaryotes and other microbes: A historical perspective and pending issues","authors":"Konstantinos T. Konstantinidis","doi":"10.1002/mlf2.12088","DOIUrl":"https://doi.org/10.1002/mlf2.12088","url":null,"abstract":"Whether prokaryotes, and other microorganisms, form distinct clusters that can be recognized as species remains an issue of paramount theoretical as well as practical consequence in identifying, regulating, and communicating about these organisms. In the past decade, comparisons of thousands of genomes of isolates and hundreds of metagenomes have shown that prokaryotic diversity may be predominantly organized in such sequence‐discrete clusters, albeit organisms of intermediate relatedness between the identified clusters are also frequently found. Accumulating evidence suggests, however, that the latter “intermediate” organisms show enough ecological and/or functional distinctiveness to be considered different species. Notably, the area of discontinuity between clusters often—but not always—appears to be around 85%–95% genome‐average nucleotide identity, consistently among different taxa. More recent studies have revealed remarkably similar diversity patterns for viruses and microbial eukaryotes as well. This high consistency across taxa implies a specific mechanistic process that underlies the maintenance of the clusters. The underlying mechanism may be a substantial reduction in the efficiency of homologous recombination, which mediates (successful) horizontal gene transfer, around 95% nucleotide identity. Deviations from the 95% threshold (e.g., species showing lower intraspecies diversity) may be caused by ecological differentiation that imposes barriers to otherwise frequent gene transfer. While this hypothesis that clusters are driven by ecological differentiation coupled to recombination frequency (i.e., higher recombination within vs. between groups) is appealing, the supporting evidence remains anecdotal. The data needed to rigorously test the hypothesis toward advancing the species concept are also outlined.","PeriodicalId":94145,"journal":{"name":"mLife","volume":"18 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138979914","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}
In several filamentous fungi, incident light and environmental stress signaling share the mitogen‐activated protein kinase (MAPK) HOG (SAK) pathway. It has been revealed that short‐term illumination with blue light triggers the activation of the HOG pathway in Trichoderma spp. In this study, we demonstrate the crucial role of the basic leucine zipper transcription factor ATF1 in blue light responses and signaling downstream of the MAPK HOG1 in Trichoderma guizhouense. The lack of ATF1 severely impaired photoconidiation and delayed vegetative growth and conidial germination. Upon blue light or H2O2 stimuli, HOG1 interacted with ATF1 in the nucleus. Genome‐wide transcriptome analyses revealed that 61.8% (509 out of 824) and 85.2% (702 out of 824) of blue light‐regulated genes depended on ATF1 and HOG1, respectively, of which 58.4% (481 out of 824) were regulated by both of them. Our results also show that blue light promoted conidial germination and HOG1 and ATF1 played opposite roles in controlling conidial germination in the dark. Additionally, the lack of ATF1 led to reduced oxidative stress resistance, probably because of the downregulation of catalase‐encoding genes. Overall, our results demonstrate that ATF1 is the downstream component of HOG1 and is responsible for blue light responses, conidial germination, vegetative growth, and oxidative stress resistance in T. guizhouense.
{"title":"The bZIP transcription factor ATF1 regulates blue light and oxidative stress responses in Trichoderma guizhouense","authors":"Yifan Li, Yanshen Li, Huanhong Lu, Tingting Sun, Jia Gao, Jian Zhang, Qirong Shen, Zhenzhong Yu","doi":"10.1002/mlf2.12089","DOIUrl":"https://doi.org/10.1002/mlf2.12089","url":null,"abstract":"In several filamentous fungi, incident light and environmental stress signaling share the mitogen‐activated protein kinase (MAPK) HOG (SAK) pathway. It has been revealed that short‐term illumination with blue light triggers the activation of the HOG pathway in Trichoderma spp. In this study, we demonstrate the crucial role of the basic leucine zipper transcription factor ATF1 in blue light responses and signaling downstream of the MAPK HOG1 in Trichoderma guizhouense. The lack of ATF1 severely impaired photoconidiation and delayed vegetative growth and conidial germination. Upon blue light or H2O2 stimuli, HOG1 interacted with ATF1 in the nucleus. Genome‐wide transcriptome analyses revealed that 61.8% (509 out of 824) and 85.2% (702 out of 824) of blue light‐regulated genes depended on ATF1 and HOG1, respectively, of which 58.4% (481 out of 824) were regulated by both of them. Our results also show that blue light promoted conidial germination and HOG1 and ATF1 played opposite roles in controlling conidial germination in the dark. Additionally, the lack of ATF1 led to reduced oxidative stress resistance, probably because of the downregulation of catalase‐encoding genes. Overall, our results demonstrate that ATF1 is the downstream component of HOG1 and is responsible for blue light responses, conidial germination, vegetative growth, and oxidative stress resistance in T. guizhouense.","PeriodicalId":94145,"journal":{"name":"mLife","volume":"53 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138602332","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}
Abstract Our knowledge of microbial processes—who is responsible for what, the rates at which they occur, and the substrates consumed and products produced—is imperfect for many if not most taxa, but even less is known about how microsite processes scale to the ecosystem and thence the globe. In both natural and managed environments, scaling links fundamental knowledge to application and also allows for global assessments of the importance of microbial processes. But rarely is scaling straightforward: More often than not, process rates in situ are distributed in a highly skewed fashion, under the influence of multiple interacting controls, and thus often difficult to sample, quantify, and predict. To date, quantitative models of many important processes fail to capture daily, seasonal, and annual fluxes with the precision needed to effect meaningful management outcomes. Nitrogen cycle processes are a case in point, and denitrification is a prime example. Statistical models based on machine learning can improve predictability and identify the best environmental predictors but are—by themselves—insufficient for revealing process‐level knowledge gaps or predicting outcomes under novel environmental conditions. Hybrid models that incorporate well‐calibrated process models as predictors for machine learning algorithms can provide both improved understanding and more reliable forecasts under environmental conditions not yet experienced. Incorporating trait‐based models into such efforts promises to improve predictions and understanding still further, but much more development is needed.
{"title":"Denitrification and the challenge of scaling microsite knowledge to the globe","authors":"G. Philip Robertson","doi":"10.1002/mlf2.12080","DOIUrl":"https://doi.org/10.1002/mlf2.12080","url":null,"abstract":"Abstract Our knowledge of microbial processes—who is responsible for what, the rates at which they occur, and the substrates consumed and products produced—is imperfect for many if not most taxa, but even less is known about how microsite processes scale to the ecosystem and thence the globe. In both natural and managed environments, scaling links fundamental knowledge to application and also allows for global assessments of the importance of microbial processes. But rarely is scaling straightforward: More often than not, process rates in situ are distributed in a highly skewed fashion, under the influence of multiple interacting controls, and thus often difficult to sample, quantify, and predict. To date, quantitative models of many important processes fail to capture daily, seasonal, and annual fluxes with the precision needed to effect meaningful management outcomes. Nitrogen cycle processes are a case in point, and denitrification is a prime example. Statistical models based on machine learning can improve predictability and identify the best environmental predictors but are—by themselves—insufficient for revealing process‐level knowledge gaps or predicting outcomes under novel environmental conditions. Hybrid models that incorporate well‐calibrated process models as predictors for machine learning algorithms can provide both improved understanding and more reliable forecasts under environmental conditions not yet experienced. Incorporating trait‐based models into such efforts promises to improve predictions and understanding still further, but much more development is needed.","PeriodicalId":94145,"journal":{"name":"mLife","volume":"2013 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135588082","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}
Yulei Li, Xi Wang, Xi Zeng, Wenbo Ren, Pu Liao, Baoli Zhu
Abstract Current influenza vaccines need to be updated annually owing to constant antigenic drift in the globular head of the viral surface hemagglutinin (HA) glycoprotein. The immunogenic subdominant stem domain of HA is highly conserved and can be recognized by antibodies capable of binding multiple HA subtypes. Therefore, the HA stem antigen is a promising target for the design of universal influenza vaccines. On the basis of an established lipid nanoparticle‐encapsulated mRNA vaccine platform, we designed and developed a novel universal influenza mRNA vaccine (mHAs) encoding the HA stem antigen of the influenza A (H1N1) virus. We tested the efficacy of the mHAs vaccine using a mouse model. The vaccine induced robust humoral and specific cellular immune responses against the stem region of HA. Importantly, two doses of the mHAs vaccine fully protected mice from lethal challenges of the heterologous H1N1 and heterosubtypic H5N8 influenza viruses. Vaccinated mice had less pathological lung damage and lower viral titers than control mice. These results suggest that an mRNA vaccine using the conserved stem region of HA may provide effective protection against seasonal and other possible influenza variants.
{"title":"Protective efficacy of a universal influenza mRNA vaccine against the challenge of H1 and H5 influenza A viruses in mice","authors":"Yulei Li, Xi Wang, Xi Zeng, Wenbo Ren, Pu Liao, Baoli Zhu","doi":"10.1002/mlf2.12085","DOIUrl":"https://doi.org/10.1002/mlf2.12085","url":null,"abstract":"Abstract Current influenza vaccines need to be updated annually owing to constant antigenic drift in the globular head of the viral surface hemagglutinin (HA) glycoprotein. The immunogenic subdominant stem domain of HA is highly conserved and can be recognized by antibodies capable of binding multiple HA subtypes. Therefore, the HA stem antigen is a promising target for the design of universal influenza vaccines. On the basis of an established lipid nanoparticle‐encapsulated mRNA vaccine platform, we designed and developed a novel universal influenza mRNA vaccine (mHAs) encoding the HA stem antigen of the influenza A (H1N1) virus. We tested the efficacy of the mHAs vaccine using a mouse model. The vaccine induced robust humoral and specific cellular immune responses against the stem region of HA. Importantly, two doses of the mHAs vaccine fully protected mice from lethal challenges of the heterologous H1N1 and heterosubtypic H5N8 influenza viruses. Vaccinated mice had less pathological lung damage and lower viral titers than control mice. These results suggest that an mRNA vaccine using the conserved stem region of HA may provide effective protection against seasonal and other possible influenza variants.","PeriodicalId":94145,"journal":{"name":"mLife","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134915611","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}
Linwei Wu, Yunfeng Yang, Daliang Ning, Qun Gao, Huaqun Yin, Naija Xiao, Benjamin Y. Zhou, Si Chen, Qiang He, Jizhong Zhou
Abstract Disentangling the assembly mechanisms controlling community composition, structure, distribution, functions, and dynamics is a central issue in ecology. Although various approaches have been proposed to examine community assembly mechanisms, quantitative characterization is challenging, particularly in microbial ecology. Here, we present a novel approach for quantitatively delineating community assembly mechanisms by combining the consumer–resource model with a neutral model in stochastic differential equations. Using time‐series data from anaerobic bioreactors that target microbial 16S rRNA genes, we tested the applicability of three ecological models: the consumer–resource model, the neutral model, and the combined model. Our results revealed that model performances varied substantially as a function of population abundance and/or process conditions. The combined model performed best for abundant taxa in the treatment bioreactors where process conditions were manipulated. In contrast, the neutral model showed the best performance for rare taxa. Our analysis further indicated that immigration rates decreased with taxa abundance and competitions between taxa were strongly correlated with phylogeny, but within a certain phylogenetic distance only. The determinism underlying taxa and community dynamics were quantitatively assessed, showing greater determinism in the treatment bioreactors that aligned with the subsequent abnormal system functioning. Given its mechanistic basis, the framework developed here is expected to be potentially applicable beyond microbial ecology.
{"title":"Assessing mechanisms for microbial taxa and community dynamics using process models","authors":"Linwei Wu, Yunfeng Yang, Daliang Ning, Qun Gao, Huaqun Yin, Naija Xiao, Benjamin Y. Zhou, Si Chen, Qiang He, Jizhong Zhou","doi":"10.1002/mlf2.12076","DOIUrl":"https://doi.org/10.1002/mlf2.12076","url":null,"abstract":"Abstract Disentangling the assembly mechanisms controlling community composition, structure, distribution, functions, and dynamics is a central issue in ecology. Although various approaches have been proposed to examine community assembly mechanisms, quantitative characterization is challenging, particularly in microbial ecology. Here, we present a novel approach for quantitatively delineating community assembly mechanisms by combining the consumer–resource model with a neutral model in stochastic differential equations. Using time‐series data from anaerobic bioreactors that target microbial 16S rRNA genes, we tested the applicability of three ecological models: the consumer–resource model, the neutral model, and the combined model. Our results revealed that model performances varied substantially as a function of population abundance and/or process conditions. The combined model performed best for abundant taxa in the treatment bioreactors where process conditions were manipulated. In contrast, the neutral model showed the best performance for rare taxa. Our analysis further indicated that immigration rates decreased with taxa abundance and competitions between taxa were strongly correlated with phylogeny, but within a certain phylogenetic distance only. The determinism underlying taxa and community dynamics were quantitatively assessed, showing greater determinism in the treatment bioreactors that aligned with the subsequent abnormal system functioning. Given its mechanistic basis, the framework developed here is expected to be potentially applicable beyond microbial ecology.","PeriodicalId":94145,"journal":{"name":"mLife","volume":"312 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135298314","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}
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