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1.
Metab Eng ; 83: 160-171, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38636729

RESUMO

Microbes have inherent capacities for utilizing various carbon sources, however they often exhibit sub-par fitness due to low metabolic efficiency. To test whether a bacterial strain can optimally utilize multiple carbon sources, Escherichia coli was serially evolved in L-lactate and glycerol. This yielded two end-point strains that evolved first in L-lactate then in glycerol, and vice versa. The end-point strains displayed a universal growth advantage on single and a mixture of adaptive carbon sources, enabled by a concerted action of carbon source-specialists and generalist mutants. The combination of just four variants of glpK, ppsA, ydcI, and rph-pyrE, accounted for more than 80% of end-point strain fitness. In addition, machine learning analysis revealed a coordinated activity of transcriptional regulators imparting condition-specific regulation of gene expression. The effectiveness of the serial adaptive laboratory evolution (ALE) scheme in bioproduction applications was assessed under single and mixed-carbon culture conditions, in which serial ALE strain exhibited superior productivity of acetoin compared to ancestral strains. Together, systems-level analysis elucidated the molecular basis of serial evolution, which hold potential utility in bioproduction applications.


Assuntos
Carbono , Evolução Molecular Direcionada , Escherichia coli , Escherichia coli/genética , Escherichia coli/metabolismo , Carbono/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Glicerol/metabolismo , Ácido Láctico/metabolismo , Engenharia Metabólica
2.
Nucleic Acids Res ; 50(7): 4171-4186, 2022 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-35357499

RESUMO

As the design of genetic circuitry for synthetic biology becomes more sophisticated, diverse regulatory bioparts are required. Despite their importance, well-characterized 3'-untranslated region (3'-UTR) bioparts are limited. Thus, transcript 3'-ends require further investigation to understand the underlying regulatory role and applications of the 3'-UTR. Here, we revisited the use of Term-Seq in the Escherichia coli strain K-12 MG1655 to enhance our understanding of 3'-UTR regulatory functions and to provide a diverse collection of tunable 3'-UTR bioparts with a wide termination strength range. Comprehensive analysis of 1,629 transcript 3'-end positions revealed multiple 3'-termini classes generated through transcription termination and RNA processing. The examination of individual Rho-independent terminators revealed a reduction in downstream gene expression over a wide range, which led to the design of novel synthetic metabolic valves that control metabolic fluxes in branched pathways. These synthetic metabolic valves determine the optimal balance of heterologous pathways for maximum target biochemical productivity. The regulatory strategy using 3'-UTR bioparts is advantageous over promoter- or 5'-UTR-based transcriptional control as it modulates gene expression at transcription levels without trans-acting element requirements (e.g. transcription factors). Our results provide a foundational platform for 3'-UTR engineering in synthetic biology applications.


Assuntos
Escherichia coli , Biologia Sintética , Regiões 3' não Traduzidas/genética , Regiões 5' não Traduzidas , Escherichia coli/genética , Escherichia coli/metabolismo , Regiões Promotoras Genéticas , Transcrição Gênica
3.
PLoS Genet ; 17(9): e1009821, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34570751

RESUMO

RNA sequencing techniques have enabled the systematic elucidation of gene expression (RNA-Seq), transcription start sites (differential RNA-Seq), transcript 3' ends (Term-Seq), and post-transcriptional processes (ribosome profiling). The main challenge of transcriptomic studies is to remove ribosomal RNAs (rRNAs), which comprise more than 90% of the total RNA in a cell. Here, we report a low-cost and robust bacterial rRNA depletion method, RiboRid, based on the enzymatic degradation of rRNA by thermostable RNase H. This method implemented experimental considerations to minimize nonspecific degradation of mRNA and is capable of depleting pre-rRNAs that often comprise a large portion of RNA, even after rRNA depletion. We demonstrated the highly efficient removal of rRNA up to a removal efficiency of 99.99% for various transcriptome studies, including RNA-Seq, Term-Seq, and ribosome profiling, with a cost of approximately $10 per sample. This method is expected to be a robust method for large-scale high-throughput bacterial transcriptomic studies.


Assuntos
Bactérias/genética , Custos e Análise de Custo , RNA Bacteriano/isolamento & purificação , RNA Ribossômico/isolamento & purificação , Transcriptoma , RNA Bacteriano/genética , RNA Ribossômico/genética , Análise de Sequência de RNA/métodos
4.
EMBO Rep ; 22(2): e51790, 2021 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-33463026

RESUMO

Bactericidal antibiotics are powerful agents due to their ability to convert essential bacterial functions into lethal processes. However, many important bacterial pathogens are remarkably tolerant against bactericidal antibiotics due to inducible damage repair responses. The cell wall damage response two-component system VxrAB of the gastrointestinal pathogen Vibrio cholerae promotes high-level ß-lactam tolerance and controls a gene network encoding highly diverse functions, including negative control over multiple iron uptake systems. How this system contributes to tolerance is poorly understood. Here, we show that ß-lactam antibiotics cause an increase in intracellular free iron levels and collateral oxidative damage, which is exacerbated in the ∆vxrAB mutant. Mutating major iron uptake systems dramatically increases ∆vxrAB tolerance to ß-lactams. We propose that VxrAB reduces antibiotic-induced toxic iron and concomitant metabolic perturbations by downregulating iron uptake transporters and show that iron sequestration enhances tolerance against ß-lactam therapy in a mouse model of cholera infection. Our results suggest that a microorganism's ability to counteract diverse antibiotic-induced stresses promotes high-level antibiotic tolerance and highlights the complex secondary responses elicited by antibiotics.


Assuntos
Vibrio cholerae , beta-Lactamas , Animais , Antibacterianos/farmacologia , Parede Celular , Camundongos , Vibrio cholerae/genética , beta-Lactamas/farmacologia
5.
Metab Eng ; 69: 59-72, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34775076

RESUMO

The microbial conversion of glycerol into value-added commodity products has emerged as an attractive means to meet the demands of biosustainability. However, glycerol is a non-preferential carbon source for productive fermentation because of its low energy density. We employed evolutionary and metabolic engineering in tandem to construct an Escherichia coli strain with improved GABA production using glycerol as the feedstock carbon. Adaptive evolution of E. coli W under glycerol-limited conditions for 1300 generations harnessed an adapted strain with a metabolic system optimized for glycerol utilization. Mutation profiling, enzyme kinetic assays, and transcriptome analysis of the adapted strain allowed us to decipher the basis of glycerol adaptation at the molecular level. Importantly, increased substrate influx mediated by the mutant glpK and modulation of intracellular cAMP levels were the key drivers of improved fitness in the glycerol-limited condition. Leveraging the enhanced capability of glycerol utilization in the strain, we constructed a GABA-producing E. coli W-derivative with superior GABA production compared to the wild-type. Furthermore, rationally designed inactivation of the non-essential metabolic genes, including ackA, mgsA, and gabT, in the glycerol-adapted strain improved the final GABA titer and specific productivity by 3.9- and 4.3-fold, respectively, compared with the wild-type.


Assuntos
Proteínas de Escherichia coli , Escherichia coli , Carbono/metabolismo , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Fermentação , Glicerol/metabolismo , Laboratórios , Engenharia Metabólica , Ácido gama-Aminobutírico/genética
6.
Nucleic Acids Res ; 48(18): 10157-10163, 2020 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-32976587

RESUMO

A genome contains the information underlying an organism's form and function. Yet, we lack formal framework to represent and study this information. Here, we introduce the Bitome, a matrix composed of binary digits (bits) representing the genomic positions of genomic features. We form a Bitome for the genome of Escherichia coli K-12 MG1655. We find that: (i) genomic features are encoded unevenly, both spatially and categorically; (ii) coding and intergenic features are recapitulated at high resolution; (iii) adaptive mutations are skewed towards genomic positions with fewer features; and (iv) the Bitome enhances prediction of adaptively mutated and essential genes. The Bitome is a formal representation of a genome and may be used to study its fundamental organizational properties.


Assuntos
Escherichia coli K12/genética , Genoma Bacteriano , Genômica
7.
Metab Eng ; 68: 174-186, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34655791

RESUMO

Bacteroides thetaiotaomicron represents a major symbiont of the human gut microbiome that is increasingly viewed as a promising candidate strain for microbial therapeutics. Here, we engineer B. thetaiotaomicron for heterologous production of non-native butyrate as a proof-of-concept biochemical at therapeutically relevant concentrations. Since B. thetaiotaomicron is not a natural producer of butyrate, we heterologously expressed a butyrate biosynthetic pathway in the strain, which led to the production of butyrate at the final concentration of 12 mg/L in a rich medium. Further optimization of butyrate production was achieved by a round of metabolic engineering guided by an expanded genome-scale metabolic model (GEM) of B. thetaiotaomicron. The in silico knock-out simulation of the expanded model showed that pta and ldhD were the potent knock-out targets to enhance butyrate production. The maximum titer and specific productivity of butyrate in the pta-ldhD double knockout mutant increased by nearly 3.4 and 4.8 folds, respectively. To our knowledge, this is the first engineering attempt that enabled butyrate production from a non-butyrate producing commensal B. thetaiotaomicron. The study also highlights that B. thetaiotaomicron can serve as an effective strain for live microbial therapeutics in human.


Assuntos
Bacteroides thetaiotaomicron , Microbioma Gastrointestinal , Butiratos , Humanos , Simbiose
8.
Int J Mol Sci ; 21(22)2020 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-33228099

RESUMO

Since the intimate relationship between microbes and human health has been uncovered, microbes have been in the spotlight as therapeutic targets for several diseases. Microbes contribute to a wide range of diseases, such as gastrointestinal disorders, diabetes and cancer. However, as host-microbiome interactions have not been fully elucidated, treatments such as probiotic administration and fecal transplantations that are used to modulate the microbial community often cause nonspecific results with serious safety concerns. As an alternative, synthetic biology can be used to rewire microbial networks such that the microbes can function as therapeutic agents. Genetic sensors can be transformed to detect biomarkers associated with disease occurrence and progression. Moreover, microbes can be reprogrammed to produce various therapeutic molecules from the host and bacterial proteins, such as cytokines, enzymes and signaling molecules, in response to a disturbed physiological state of the host. These therapeutic treatment systems are composed of several genetic parts, either identified in bacterial endogenous regulation systems or developed through synthetic design. Such genetic components are connected to form complex genetic logic circuits for sophisticated therapy. In this review, we discussed the synthetic biology strategies that can be used to construct engineered therapeutic microbes for improved microbiome-based treatment.


Assuntos
Diabetes Mellitus/terapia , Disbiose/terapia , Gastroenteropatias/terapia , Engenharia Genética/métodos , Neoplasias/terapia , Biologia Sintética/métodos , Animais , Diabetes Mellitus/microbiologia , Diabetes Mellitus/patologia , Modelos Animais de Doenças , Disbiose/microbiologia , Disbiose/patologia , Escherichia coli/genética , Escherichia coli/metabolismo , Transplante de Microbiota Fecal/métodos , Gastroenteropatias/microbiologia , Gastroenteropatias/patologia , Microbioma Gastrointestinal/genética , Redes Reguladoras de Genes , Humanos , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Camundongos , Neoplasias/microbiologia , Neoplasias/patologia , Probióticos/uso terapêutico , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
9.
Int J Mol Sci ; 21(3)2020 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-32024292

RESUMO

A large proportion of the recombinant proteins manufactured today rely on microbe-based expression systems owing to their relatively simple and cost-effective production schemes. However, several issues in microbial protein expression, including formation of insoluble aggregates, low protein yield, and cell death are still highly recursive and tricky to optimize. These obstacles are usually rooted in the metabolic capacity of the expression host, limitation of cellular translational machineries, or genetic instability. To this end, several microbial strains having precisely designed genomes have been suggested as a way around the recurrent problems in recombinant protein expression. Already, a growing number of prokaryotic chassis strains have been genome-streamlined to attain superior cellular fitness, recombinant protein yield, and stability of the exogenous expression pathways. In this review, we outline challenges associated with heterologous protein expression, some examples of microbial chassis engineered for the production of recombinant proteins, and emerging tools to optimize the expression of heterologous proteins. In particular, we discuss the synthetic biology approaches to design and build and test genome-reduced microbial chassis that carry desirable characteristics for heterologous protein expression.


Assuntos
Bactérias/metabolismo , Bioengenharia/métodos , Biotecnologia/métodos , Regulação da Expressão Gênica , Engenharia Metabólica/métodos , Proteínas Recombinantes/biossíntese , Animais , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Humanos , Proteínas Recombinantes/genética
10.
J Bacteriol ; 200(7)2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29358499

RESUMO

Pyruvate is an important intermediate of central carbon metabolism and connects a variety of metabolic pathways in Escherichia coli Although the intracellular pyruvate concentration is dynamically altered and tightly balanced during cell growth, the pyruvate transport system remains unclear. Here, we identified a pyruvate transporter in E. coli using high-throughput transposon sequencing. The transposon mutant library (a total of 5 × 105 mutants) was serially grown with a toxic pyruvate analog (3-fluoropyruvate [3FP]) to enrich for transposon mutants lacking pyruvate transport function. A total of 52 candidates were selected on the basis of a stringent enrichment level of transposon insertion frequency in response to 3FP treatment. Subsequently, their pyruvate transporter function was examined by conventional functional assays, such as those measuring growth inhibition by the toxic pyruvate analog and pyruvate uptake activity. The pyruvate transporter system comprises CstA and YbdD, which are known as a peptide transporter and a conserved protein, respectively, whose functions are associated with carbon starvation conditions. In addition to the presence of more than one endogenous pyruvate importer, it has been suggested that the E. coli genome encodes constitutive and inducible pyruvate transporters. Our results demonstrated that CstA and YbdD comprise the constitutive pyruvate transporter system in E. coli, which is consistent with the tentative genomic locus previously suggested and the functional relationship with the extracellular pyruvate sensing system. The identification of this pyruvate transporter system provides valuable genetic information for understanding the complex process of pyruvate metabolism in E. coliIMPORTANCE Pyruvate is an important metabolite as a central node in bacterial metabolism, and its intracellular levels are tightly regulated to maintain its functional roles in highly interconnected metabolic pathways. However, an understanding of the mechanism of how bacterial cells excrete and transport pyruvate remains elusive. Using high-throughput transposon sequencing followed by pyruvate uptake activity testing of the selected candidate genes, we found that a pyruvate transporter system comprising CstA and YbdD, currently annotated as a peptide transporter and a conserved protein, respectively, constitutively transports pyruvate. The identification of the physiological role of the pyruvate transporter system provides valuable genetic information for understanding the complex pyruvate metabolism in Escherichia coli.


Assuntos
Proteínas de Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Membrana Transportadoras/genética , Ácido Pirúvico/metabolismo , Transativadores/genética , Transporte Biológico , Elementos de DNA Transponíveis , Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Sequenciamento de Nucleotídeos em Larga Escala , Proteínas de Membrana Transportadoras/metabolismo , Transportadores de Ácidos Monocarboxílicos , Transativadores/metabolismo
11.
J Nanosci Nanotechnol ; 15(5): 3852-61, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-26505015

RESUMO

Clostridium aceticum is an anaerobic homoacetogen, able to reduce CO2 to multi-carbon products using the reductive acetyl-CoA pathway. This unique ability to use CO2 or CO makes the microbe a potential platform for the biotech industry. However, the development of genetically engineered homoacetogen for the large-scale production of commodity chemicals is hampered by the limited amount of their genetic and metabolic information. Here we exploited next-generation sequencing to reveal C. aceticum genome. The short-read sequencing produced 44,871,196 high quality reads with an average length of 248 bases. Following sequence trimming step, 30,256,976 reads were assembled into 12,563 contigs with 168-fold coverage and 1,971 bases in length using de Bruijn graph algorithm. Since the k-mer hash length in the algorithm is an important factor for the quality of output contigs, a window of k-mers (k-51 to k-201) was tested to obtain high quality contigs. In addition to the assembly metrics, the functional annotation of the contigs was investigated to select the k-mer optimum. Metabolic pathway mapping using the functional annotation identified the majority of central metabolic pathways, such as the glycolysis and TCA cycle. Further, these analyses elucidated the enzymes consisting of Wood-Ljungdahl pathway, in which CO2 is fixed into acetyl-CoA. Thus, the metabolic reconstruction based on the draft genome assembly provides a foundation for the functional genomics required to engineer C. aceticum.


Assuntos
Clostridium/genética , Genoma Bacteriano/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Redes e Vias Metabólicas/genética , Análise de Sequência de DNA/métodos , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Clostridium/metabolismo , DNA Bacteriano/análise , DNA Bacteriano/genética , Dados de Sequência Molecular , Alinhamento de Sequência
12.
Trends Biotechnol ; 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38423803

RESUMO

Advances in systems and synthetic biology have propelled the construction of reduced bacterial genomes. Genome reduction was initially focused on exploring properties of minimal genomes, but more recently it has been deployed as an engineering strategy to enhance strain performance. This review provides the latest updates on reduced genomes, focusing on dual-track approaches of top-down reduction and bottom-up synthesis for their construction. Using cases from studies that are based on established industrial workhorse strains, we discuss the construction of a series of synthetic phenotypes that are candidates for biotechnological applications. Finally, we address the possible uses of reduced genomes for biotechnological applications and the needed future research directions that may ultimately lead to the total synthesis of rationally designed genomes.

13.
Nat Commun ; 15(1): 2356, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38490991

RESUMO

Machine learning applied to large compendia of transcriptomic data has enabled the decomposition of bacterial transcriptomes to identify independently modulated sets of genes, such iModulons represent specific cellular functions. The identification of iModulons enables accurate identification of genes necessary and sufficient for cross-species transfer of cellular functions. We demonstrate cross-species transfer of: 1) the biotransformation of vanillate to protocatechuate, 2) a malonate catabolic pathway, 3) a catabolic pathway for 2,3-butanediol, and 4) an antimicrobial resistance to ampicillin found in multiple Pseudomonas species to Escherichia coli. iModulon-based engineering is a transformative strategy as it includes all genes comprising the transferred cellular function, including genes without functional annotation. Adaptive laboratory evolution was deployed to optimize the cellular function transferred, revealing mutations in the host. Combining big data analytics and laboratory evolution thus enhances the level of understanding of systems biology, and synthetic biology for strain design and development.


Assuntos
Escherichia coli , Biologia Sintética , Escherichia coli/genética , Escherichia coli/metabolismo , Genes Bacterianos , Pseudomonas/genética
14.
mSystems ; 8(1): e0089622, 2023 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-36507678

RESUMO

The massive sequencing of transposon insertion mutant libraries (Tn-Seq) represents a commonly used method to determine essential genes in bacteria. Using a hypersaturated transposon mutant library consisting of 400,096 unique Tn insertions, 523 genes were classified as essential in Escherichia coli K-12 MG1655. This provided a useful genome-wide gene essentiality landscape for rapidly identifying 233 of 301 essential genes previously validated by a knockout study. However, there was a discrepancy in essential gene sets determined by conventional gene deletion methods and Tn-Seq, although different Tn-Seq studies reported different extents of discrepancy. We have elucidated two causes of this discrepancy. First, 68 essential genes not detected by Tn-Seq contain nonessential subgenic domains that are tolerant to transposon insertion, which leads to the false assignment of an essential gene as a nonessential or dispensable gene. These genes exhibited a high level of transposon insertion in their subgenic nonessential domains. In contrast, 290 genes were additionally categorized as essential by Tn-Seq, although their knockout mutants were available. The comparative analysis of Tn-Seq and high-resolution footprinting of nucleoid-associated proteins (NAPs) revealed that a protein-DNA interaction hinders transposon insertion. We identified 213 false-positive genes caused by NAP-genome interactions. These two limitations have to be considered when addressing essential bacterial genes using Tn-Seq. Furthermore, a comparative analysis of high-resolution Tn-Seq with other data sets is required for a more accurate determination of essential genes in bacteria. IMPORTANCE Transposon mutagenesis is an efficient way to explore gene essentiality of a bacterial genome. However, there was a discrepancy between the essential gene set determined by transposon mutagenesis and that determined using single-gene knockout strains. In this study, we generated a hypersaturated Escherichia coli transposon mutant library comprising approximately 400,000 different mutants. Determination of transposon insertion sites using next-generation sequencing provided a high-resolution essentiality landscape of the E. coli genome. We identified false negatives of essential gene discovery due to the permissive insertion of transposons in the C-terminal region. Comparisons between the transposon insertion landscape with binding profiles of DNA-binding proteins revealed interference of nucleoid-associated proteins to transposon insertion, generating false positives of essential gene discovery. Consideration of these findings is required to avoid the misinterpretation of transposon mutagenesis results.


Assuntos
Escherichia coli K12 , Escherichia coli , Escherichia coli/genética , Mutagênese Insercional , Escherichia coli K12/genética , Elementos de DNA Transponíveis/genética , Genoma Bacteriano
15.
Front Bioeng Biotechnol ; 10: 844200, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35284422

RESUMO

Bacteria belonging to Streptomyces have the ability to produce a wide range of secondary metabolites through a shift from primary to secondary metabolism regulated by complex networks activated after vegetative growth terminates. Despite considerable effort to understand the regulatory elements governing gene expression related to primary and secondary metabolism in Streptomyces, system-level information remains limited. In this study, we integrated four multi-omics datasets from Streptomyces griseus NBRC 13350: RNA-seq, ribosome profiling, dRNA-seq, and Term-Seq, to analyze the regulatory elements of transcription and translation of differentially expressed genes during cell growth. With the functional enrichment of gene expression in different growth phases, one sigma factor regulon and four transcription factor regulons governing differential gene transcription patterns were found. In addition, the regulatory elements of transcription termination and post-transcriptional processing at transcript 3'-end positions were elucidated, including their conserved motifs, stem-loop RNA structures, and non-terminal locations within the polycistronic operons, and the potential regulatory elements of translation initiation and elongation such as 5'-UTR length, RNA structures at ribosome-bound sites, and codon usage were investigated. This comprehensive genetic information provides a foundational genetic resource for strain engineering to enhance secondary metabolite production in Streptomyces.

16.
Sci Data ; 9(1): 197, 2022 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-35538082

RESUMO

The gut microbiota is associated with the health and longevity of the host. A few methods, such as fecal microbiota transplantation and oral administration of probiotics, have been applied to alter the gut microbiome and promote healthy aging. The changes in host microbiomes still remain poorly understood. Here, we characterized both the changes in gut microbial communities and their functional potential derived from colon samples in mouse models during aging. We achieved this through four procedures including co-housing, serum injection, parabiosis, and oral administration of Akkermansia muciniphila as probiotics using bacterial 16 S rRNA sequencing and shotgun metagenomic sequencing. The dataset comprised 16 S rRNA sequencing (36,249,200 paired-end reads, 107 sequencing data) and metagenomic sequencing data (307,194,369 paired-end reads, 109 sequencing data), characterizing the taxonomy of bacterial communities and their functional potential during aging and rejuvenation. The generated data expand the resources of the gut microbiome related to aging and rejuvenation and provide a useful dataset for research on developing therapeutic strategies to achieve healthy active aging.


Assuntos
Envelhecimento , Microbioma Gastrointestinal , RNA Ribossômico 16S , Envelhecimento/genética , Animais , Modelos Animais de Doenças , Microbioma Gastrointestinal/genética , Metagenômica , Camundongos , RNA Ribossômico 16S/genética , Rejuvenescimento
17.
Comput Struct Biotechnol J ; 19: 2468-2476, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34025937

RESUMO

The market for using and storing digital data is growing, with DNA synthesis emerging as an efficient way to store massive amounts of data. Storing information in DNA mainly consists of two steps: data writing and reading. The writing step requires encoding data in DNA, building one nucleotide at a time as a form of single-stranded DNA (ssDNA). Once the data needs to be read, the target DNA is selectively retrieved and sequenced, which will also be in the form of an ssDNA. Recently, enzyme-based DNA synthesis is emerging as a new method to be a breakthrough on behalf of decades-old chemical synthesis. A few enzymatic methods have been presented for data memory, including the use of terminal deoxynucleotidyl transferase. Besides, enzyme-based amplification or denaturation of the target strand into ssDNA provides selective access to the desired dataset. In this review, we summarize diverse enzymatic methods for either synthesizing ssDNA or retrieving the data-containing DNA.

18.
mSystems ; 6(3)2021 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-33947798

RESUMO

Identification of transcriptional regulatory elements in the GC-rich Streptomyces genome is essential for the production of novel biochemicals from secondary metabolite biosynthetic gene clusters (smBGCs). Despite many efforts to understand the regulation of transcription initiation in smBGCs, information on the regulation of transcription termination and posttranscriptional processing remains scarce. In this study, we identified the transcriptional regulatory elements in ß-lactam antibiotic-producing Streptomyces clavuligerus ATCC 27064 by determining a total of 1,427 transcript 3'-end positions (TEPs) using the term-seq method. Termination of transcription was governed by three classes of TEPs, of which each displayed unique sequence features. The data integration with transcription start sites and transcriptome data generated 1,648 transcription units (TUs) and 610 transcription unit clusters (TUCs). TU architecture showed that the transcript abundance in TU isoforms of a TUC was potentially affected by the sequence context of their TEPs, suggesting that the regulatory elements of TEPs could control the transcription level in additional layers. We also identified TU features of a xenobiotic response element (XRE) family regulator and DUF397 domain-containing protein, particularly showing the abundance of bidirectional TEPs. Finally, we found that 189 noncoding TUs contained potential cis- and trans-regulatory elements that played a major role in regulating the 5' and 3' UTR. These findings highlight the role of transcriptional regulatory elements in transcription termination and posttranscriptional processing in Streptomyces sp.IMPORTANCE Streptomyces sp. is a great source of bioactive secondary metabolites, including antibiotics, antifungal agents, antiparasitic agents, immunosuppressant compounds, and other drugs. Secondary metabolites are synthesized via multistep conversions of the precursor molecules from primary metabolism, governed by multicomplex enzymes from secondary metabolite biosynthetic gene clusters. As their production is closely related with the growth phase and dynamic cellular status in response to various intra- and extracellular signals, complex regulatory systems tightly control the gene expressions related to secondary metabolism. In this study, we determined genome-wide transcript 3'-end positions and transcription units in the ß-lactam antibiotic producer Streptomyces clavuligerus ATCC 27064 to elucidate the transcriptional regulatory elements in transcription termination and posttranscriptional processing by integration of multiomics data. These unique features, such as transcript 3'-end sequence, potential riboregulators, and potential 3'-untranslated region (UTR) cis-regulatory elements, can be potentially used to design engineering tools that can regulate the transcript abundance of genes for enhancing secondary metabolite production.

19.
Microbiome ; 9(1): 240, 2021 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-34906228

RESUMO

BACKGROUND: The gut microbiota is associated with diverse age-related disorders. Several rejuvenation methods, such as probiotic administration and faecal microbiota transplantation, have been applied to alter the gut microbiome and promote healthy ageing. Nevertheless, prolongation of the health span of aged mice by remodelling the gut microbiome remains challenging. RESULTS: Here, we report the changes in gut microbial communities and their functions in mouse models during ageing and three rejuvenation procedures including co-housing, serum-injection and parabiosis. Our results showed that the compositional structure and gene abundance of the intestinal microbiota changed dynamically during the ageing process. Through the three rejuvenation procedures, we observed that the microbial community and intestinal immunity of aged mice were comparable to those of young mice. The results of metagenomic data analysis underscore the importance of the high abundance of Akkermansia and the butyrate biosynthesis pathway in the rejuvenated mouse group. Furthermore, oral administration of Akkermansia sufficiently ameliorated the senescence-related phenotype in the intestinal systems in aged mice and extended the health span, as evidenced by the frailty index and restoration of muscle atrophy. CONCLUSIONS: In conclusion, the changes in key microbial communities and their functions during ageing and three rejuvenation procedures, and the increase in the healthy lifespan of aged mice by oral administration of Akkermansia. Our results provide a rationale for developing therapeutic strategies to achieve healthy active ageing. Video abstract.


Assuntos
Microbioma Gastrointestinal , Envelhecimento Saudável , Microbiota , Envelhecimento , Animais , Microbioma Gastrointestinal/genética , Camundongos , Rejuvenescimento
20.
J Microbiol ; 58(3): 217-226, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31989542

RESUMO

Gene expression changes in response to diverse environmental stimuli to regulate numerous cellular functions. Genes are expressed into their functional products with the help of messenger RNA (mRNA). Thus, measuring levels of mRNA in cells is important to understand cellular functions. With advances in next-generation sequencing (NGS), the abundance of cellular mRNA has been elucidated via transcriptome sequencing. However, several studies have found a discrepancy between mRNA abundance and protein levels induced by translational regulation, including different rates of ribosome entry and translational pausing. As such, the levels of mRNA are not necessarily a direct representation of the protein levels found in a cell. To determine a more precise way to measure protein expression in cells, the analysis of the levels of mRNA associated with ribosomes is being adopted. With an aid of NGS techniques, a single nucleotide resolution footprint of the ribosome was determined using a method known as Ribo-Seq or ribosome profiling. This method allows for the high-throughput measurement of translation in vivo, which was further analyzed to determine the protein synthesis rate, translational pausing, and cellular responses toward a variety of environmental changes. Here, we describe a simple analysis pipeline for Ribo-Seq in bacteria, so-called simple translatome analysis tool for Ribo-Seq (STATR). STATR can be used to carry out the primary processing of Ribo-Seq data, subsequently allowing for multiple levels of translatome study, from experimental validation to in-depth analyses. A command-by-command explanation is provided here to allow a broad spectrum of biologists to easily reproduce the analysis.


Assuntos
Bactérias/genética , RNA Mensageiro/genética , RNA Ribossômico/genética , RNA-Seq/métodos , Software , Análise de Dados , Instruções Programadas como Assunto , RNA Bacteriano/genética , Ribossomos/genética
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