scholarly journals Cas12a-assisted precise targeted cloning using in vivo Cre-lox recombination

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Behnam Enghiad ◽  
Chunshuai Huang ◽  
Fang Guo ◽  
Guangde Jiang ◽  
Bin Wang ◽  
...  
Keyword(s):  
Natural Products ◽  
Heterologous Expression ◽  
Large Scale ◽  
Gc Content ◽  
Gene Clusters ◽  
Dna Assembly ◽  
Vast Number ◽  
Direct Cloning ◽  
Cloning Method

AbstractDirect cloning represents the most efficient strategy to access the vast number of uncharacterized natural product biosynthetic gene clusters (BGCs) for the discovery of novel bioactive compounds. However, due to their large size, repetitive nature, or high GC-content, large-scale cloning of these BGCs remains an overwhelming challenge. Here, we report a scalable direct cloning method named Cas12a-assisted precise targeted cloning using in vivo Cre-lox recombination (CAPTURE) which consists of Cas12a digestion, a DNA assembly approach termed T4 polymerase exo + fill-in DNA assembly, and Cre-lox in vivo DNA circularization. We apply this method to clone 47 BGCs ranging from 10 to 113 kb from both Actinomycetes and Bacilli with ~100% efficiency. Heterologous expression of cloned BGCs leads to the discovery of 15 previously uncharacterized natural products including six cyclic head-to-tail heterodimers with a unique 5/6/6/6/5 pentacyclic carbon skeleton, designated as bipentaromycins A–F. Four of the bipentaromycins show strong antimicrobial activity to both Gram-positive and Gram-negative bacteria such as methicillin-resistant Staphylococcus aureus, vancomycinresistant Enterococcus faecium, and bioweapon Bacillus anthracis. Due to its robustness and efficiency, our direct cloning method coupled with heterologous expression provides an effective strategy for large-scale discovery of novel natural products.

scholarly journals Refactoring the formicamycin biosynthetic gene cluster to make high-level producing strains and new molecules

2020 ◽  
Author(s):  
Rebecca Devine ◽  
Hannah McDonald ◽  
Zhiwei Qin ◽  
Corinne Arnold ◽  
Katie Noble ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Large Scale ◽  
Liquid Culture ◽  
Gene Clusters ◽  
Biosynthetic Gene Cluster ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Biosynthetic Gene ◽  
Biosynthetic Genes

AbstractThe formicamycins are promising antibiotics with potent activity against Gram-positive pathogens including VRE and MRSA and display a high barrier to selection of resistant isolates. They were first identified in Streptomyces formicae KY5, which produces the formicamycins at low levels on solid agar but not in liquid culture, thus hindering further investigation of these promising antibacterial compounds. We hypothesised that by understanding the organisation and regulation of the for biosynthetic gene cluster, we could rationally refactor the cluster to increase production levels. Here we report that the for biosynthetic gene cluster consists of 24 genes expressed on nine transcripts. Seven of these transcripts, including those containing all the major biosynthetic genes, are repressed by the MarR-regulator ForJ which also controls the expression of the ForGF two-component system that initiates biosynthesis. A third cluster-situated regulator, ForZ, autoregulates and controls production of the putative MFS transporter ForAA. Consistent with these findings, deletion of forJ increased formicamycin biosynthesis 5-fold, while over-expression of forGF in the ΔforJ background increased production 10-fold compared to the wild-type. De-repression by deleting forJ also switched on biosynthesis in liquid-culture and induced the production of two novel formicamycin congeners. By combining mutations in regulatory and biosynthetic genes, six new biosynthetic precursors with antibacterial activity were also isolated. This work demonstrates the power of synthetic biology for the rational redesign of antibiotic biosynthetic gene clusters both to engineer strains suitable for fermentation in large scale bioreactors and to generate new molecules.ImportanceAntimicrobial resistance is a growing threat as existing antibiotics become increasingly ineffective against drug resistant pathogens. Here we determine the transcriptional organisation and regulation of the gene cluster encoding biosynthesis of the formicamycins, promising new antibiotics with activity against drug resistant bacteria. By exploiting this knowledge, we construct stable mutant strains which over-produce these molecules in both liquid and solid culture whilst also making some new compound variants. This will facilitate large scale purification of these molecules for further study including in vivo experiments and the elucidation of their mechanism of action. Our work demonstrates that understanding the regulation of natural product biosynthetic pathways can enable rational improvement of the producing strains.

scholarly journals Discovery and Biosynthesis of Natural Products from New Zealand Soil Metagenome Libraries

2021 ◽  
Author(s):  
◽  
Luke Stevenson
Keyword(s):  
Natural Products ◽  
New Zealand ◽  
Heterologous Expression ◽  
Gene Clusters ◽  
Bioinformatic Analysis ◽  
Coli Strain ◽  
Functional Screening ◽  
Functional Difference ◽  
Biosynthetic Pathways ◽  
New Members

<p>Antibiotic discovery rates dramatically declined following the “golden age” of the 1940’s to the 1960’s. The platforms that underpinned that age of discovery rested upon laboratory cultivation of a small clade of bacteria, the actinomycetes, primarily isolated from soil environments. Fermentation extracts of these isolated bacteria have provided the majority of antibiotics and anticancer small molecules still used today. By applying modern genetic analysis techniques to these same environmental sources that have previously yielded such success, we can uncover new biosynthetic pathways, and bioactive compounds. The work described in this thesis investigated New Zealand soil metagenomes for this purpose.  Four large metagenome libraries were constructed from the microbiomes of diverse soil environments. These were then interrogated by a functional screening approach in a knockout Escherichia coli strain, to recover a large collection of the biosynthetic gene clusters responsible for bacterial secondary metabolite production. Using different modes of bioinformatic analysis, these gene clusters were demonstrated to have both phylogenetic divergence, and functional difference from bacterial biosynthesis pathways previously discovered from culture based studies.  Two additional biosynthetic pathways were recovered from one of these metagenome libraries, and in each case found to have novel genetic features. These gene clusters were further studied by heterologous expression within Streptomyces albus production hosts. One of these gene clusters produced small aromatic polyketide compounds, the structure of one of which was solved by chemical analytic techniques, and found to be a new chemical entity.  The second gene cluster was demonstrated to have similarity to known aureolic acid biosynthesis gene clusters – a class of potent anticancer natural products. Heterologous expression resulted in the production of many metabolites, two of which were characterised and found to be new members of this chemical class.  The research in this thesis both validates the use of metagenomic analysis for future natural product discovery efforts, and adds to a growing body of evidence that understudied clades of bacteria have an untapped biosynthetic potential that can be accessed by metagenomic methods.</p>

Characterization and analysis of an industrial strain of Streptomyces bingchenggensis by genome sequencing and gene microarray

Genome ◽  
2013 ◽  
Vol 56 (11) ◽  
pp. 677-689 ◽  
Author(s):  
Xiang-Jing Wang ◽  
Bo Zhang ◽  
Yi-Jun Yan ◽  
Jing An ◽  
Ji Zhang ◽  
...  
Keyword(s):  
Natural Products ◽  
Gene Cluster ◽  
Crop Protection ◽  
Gc Content ◽  
Gene Clusters ◽  
High Expression ◽  
Expression Level ◽  
Transcriptional Analysis ◽  
Streptomyces Bingchenggensis ◽  
High Expression Level

Streptomyces bingchenggensis is a soil bacterium that produces milbemycins, a family of macrolide antibiotics that are commercially important in crop protection and veterinary medicine. In addition, S. bingchenggensis produces many other natural products including the polyether nanchangmycin and novel cyclic pentapeptides. To identify the gene clusters involved in the biosynthesis of these compounds, and better clarify the biochemical pathways of these gene clusters, the whole genome of S. bingchenggensis was sequenced, and the transcriptome profile was subsequently investigated by microarray. In comparison with other sequenced genomes in Streptomyces, S. bingchenggensis has the largest linear chromosome consisting of 11 936 683 base pairs (bp), with an average GC content of 70.8%. The 10 023 predicted protein-coding sequences include at least 47 gene clusters correlated with the biosynthesis of known or predicted secondary metabolites. Transcriptional analysis demonstrated an extremely high expression level of the milbemycin gene cluster during the entire growth period and a moderately high expression level of the nanchangmycin gene cluster during the initial hours that subsequently decreased. However, other gene clusters appear to be silent. The genome-wide analysis of the secondary metabolite gene clusters in S. bingchenggensis, coupled with transcriptional analysis, will facilitate the rational development of high milbemycins-producing strains as well as the discovery of new natural products.

scholarly journals Heterologous Expression of a Cryptic Gene Cluster from Streptomyces leeuwenhoekii C34T Yields a Novel Lasso Peptide, Leepeptin

2019 ◽  
Vol 85 (23) ◽  
Author(s):  
Juan Pablo Gomez-Escribano ◽  
Jean Franco Castro ◽  
Valeria Razmilic ◽  
Scott A. Jarmusch ◽  
Gerhard Saalbach ◽  
...  
Keyword(s):  
Natural Products ◽  
Heterologous Expression ◽  
Streptomyces Coelicolor ◽  
Gene Clusters ◽  
Bioinformatic Analysis ◽  
Growth Media ◽  
Content Type ◽  
Lasso Peptide ◽  
Lasso Peptides ◽  
New Family

ABSTRACT Analysis of the genome sequence of Streptomyces leeuwenhoekii C34T identified biosynthetic gene clusters (BGCs) for three different lasso peptides (Lp1, Lp2, and Lp3) which were not known to be made by the strain. Lasso peptides represent relatively new members of the RiPP (ribosomally synthesized and posttranslationally modified peptides) family of natural products and have not been extensively studied. Lp3, whose production could be detected in culture supernatants from S. leeuwenhoekii C34T and after heterologous expression of its BGC in Streptomyces coelicolor, is identical to the previously characterized chaxapeptin. Lp1, whose production could not be detected or achieved heterologously, appears to be identical to a recently identified member of the citrulassin family of lasso peptides. Since production of Lp2 by S. leeuwenhoekii C34T was not observed, its BGC was also expressed in S. coelicolor. The lasso peptide was isolated and its structure confirmed by mass spectrometry and nuclear magnetic resonance analyses, revealing a novel structure that appears to represent a new family of lasso peptides. IMPORTANCE Recent developments in genome sequencing combined with bioinformatic analysis have revealed that actinomycetes contain a plethora of unexpected BGCs and thus have the potential to produce many more natural products than previously thought. This reflects the inability to detect the production of these compounds under laboratory conditions, perhaps through the use of inappropriate growth media or the absence of the environmental cues required to elicit expression of the corresponding BGCs. One approach to overcoming this problem is to circumvent the regulatory mechanisms that control expression of the BGC in its natural host by deploying heterologous expression. The generally compact nature of lasso peptide BGCs makes them particularly amenable to this approach, and, in the example given here, analysis revealed a new member of the lasso peptide family of RiPPs. This approach should be readily applicable to other cryptic lasso peptide gene clusters and would also facilitate the design and production of nonnatural variants by changing the sequence encoding the core peptide, as has been achieved with other classes of RiPPs.

scholarly journals Neuroprotective Strategies for Neurological Disorders by Natural Products: An update

2019 ◽  
Vol 17 (3) ◽  
pp. 247-267 ◽  
Author(s):  
Muneeb U. Rehman ◽  
Adil Farooq Wali ◽  
Anas Ahmad ◽  
Sheeba Shakeel ◽  
Saiema Rasool ◽  
...  
Keyword(s):  
Natural Products ◽  
Large Scale ◽  
Biological Properties ◽  
In Vivo Studies ◽  
Preclinical Models ◽  
Neuroprotective Effects ◽  
Neuroprotective Strategies ◽  
Inflammatory Processes

Nature has bestowed mankind with surplus resources (natural products) on land and water. Natural products have a significant role in the prevention of disease and boosting of health in humans and animals. These natural products have been experimentally documented to possess various biological properties such as antioxidant, anti-inflammatory and anti-apoptotic activities. In vitro and in vivo studies have further established the usefulness of natural products in various preclinical models of neurodegenerative disorders. Natural products include phytoconstituents, like polyphenolic antioxidants, found in herbs, fruits, nuts, vegetables and also in marine and freshwater flora. These phytoconstituents may potentially suppress neurodegeneration and improve memory as well as cognitive functions of the brain. Also, they are known to play a pivotal role in the prevention and cure of different neurodegenerative diseases, such as Alzheimer’s disease, epilepsy, Parkinson’s disease and other neuronal disorders. The large-scale neuro-pharmacological activities of natural products have been documented due to the result of either the inhibition of inflammatory processes, or the up-regulation of various cell survival proteins or a combination of both. Due to the scarcity of human studies on neuroprotective effects of natural products, this review focuses on the various established activities of natural products in in vitro and in vivo preclinical models, and their potential neuro-therapeutic applications using the available knowledge in the literature.

scholarly journals Genome-wide analysis of the role of the antibiotic biosynthesis regulator AbsA2 inStreptomyces coelicolorA3(2)

2018 ◽  
Author(s):  
Richard A. Lewis ◽  
Abdul Wahab ◽  
Giselda Bucca ◽  
Emma E. Laing ◽  
Carla Möller-Levet ◽  
...  
Keyword(s):  
Large Scale ◽  
Time Course ◽  
Streptomyces Coelicolor ◽  
Gene Clusters ◽  
Biosynthetic Gene Cluster ◽  
Negative Influence ◽  
Antibiotic Biosynthesis ◽  
Biosynthetic Gene

AbstractThe AbsA1-AbsA2 two component signalling system ofStreptomyces coelicolorhas long been known to exert a powerful negative influence on the production of the antibiotics actinorhodin, undecylprodiginine and the Calcium-Dependent Antibiotic (CDA). Here we report the analysis of aΔabsA2deletion strain, which exhibits the classic precocious antibiotic hyper-production phenotype, and its complementation by an N-terminal triple-FLAG-tagged version of AbsA2. The complemented and non-complementedΔabsA2mutant strains were used in large-scale microarray-based time-course experiments to investigate the effect of deletingabsA2on gene expression and to identify thein vivoAbsA2 DNA-binding target sites using ChIP-on chip. We show that in addition to binding to the promoter regions ofredZandactII-orfIVAbsA2 binds to several previously unidentified sites within thecdabiosynthetic gene cluster within and/or upstream ofSCO3215-SCO3216,SCO3217,SCO3229-SCO3230, andSCO3226, and we relate the pattern of AbsA2 binding to the results of the transcriptomic study and antibiotic phenotypic assays. Interestingly, dual ‘biphasic’ ChIP peaks were observed with AbsA2 binding across the regulatory genesactII-orfIVandredZand theabsA2gene itself, while more conventional single promoter-proximal peaks were seen at the CDA biosynthetic genes suggesting a different mechanism of regulation of the former loci. Taken together the results shed light on the complex mechanism of regulation of antibiotic biosynthesis inStreptomyces coelicolorand the important role of AbsA2 in controlling the expression of three antibiotic biosynthetic gene clusters.

scholarly journals Prediction and characterization of enzymatic activities guided by sequence similarity and genome neighborhood networks

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Suwen Zhao ◽  
Ayano Sakai ◽  
Xinshuai Zhang ◽  
Matthew W Vetting ◽  
Ritesh Kumar ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Large Scale ◽  
Sequence Similarity ◽  
Gene Clusters ◽  
Enzymatic Activities ◽  
Or Gene ◽  
Enzyme Functions

Metabolic pathways in eubacteria and archaea often are encoded by operons and/or gene clusters (genome neighborhoods) that provide important clues for assignment of both enzyme functions and metabolic pathways. We describe a bioinformatic approach (genome neighborhood network; GNN) that enables large scale prediction of the in vitro enzymatic activities and in vivo physiological functions (metabolic pathways) of uncharacterized enzymes in protein families. We demonstrate the utility of the GNN approach by predicting in vitro activities and in vivo functions in the proline racemase superfamily (PRS; InterPro IPR008794). The predictions were verified by measuring in vitro activities for 51 proteins in 12 families in the PRS that represent ~85% of the sequences; in vitro activities of pathway enzymes, carbon/nitrogen source phenotypes, and/or transcriptomic studies confirmed the predicted pathways. The synergistic use of sequence similarity networks3 and GNNs will facilitate the discovery of the components of novel, uncharacterized metabolic pathways in sequenced genomes.

scholarly journals Direct preparation of Cas9 ribonucleoprotein from E. coli for PCR-free seamless DNA assembly

2018 ◽  
Author(s):  
Wenqiang Li ◽  
Shuntang Li ◽  
Jie Qiao ◽  
Fei Wang ◽  
Yang Liu ◽  
...  
Keyword(s):  
Large Scale ◽  
Genome Engineering ◽  
Restriction Enzymes ◽  
General Strategy ◽  
Dna Assembly ◽  
E Coli ◽  
Assembly Method ◽  
Direct Preparation

AbstractCRISPR-Cas9 is a versatile and powerful genome engineering tool. Recently, Cas9 ribonucleoprotein (RNP) complexes have been used as promising biological tools with plenty of in vivo and in vitro applications, but there are by far no efficient methods to produce Cas9 RNP at large scale and low cost. Here, we describe a simple and effective approach for direct preparation of Cas9 RNP from E. coli by co-expressing Cas9 and target specific single guided RNAs. The purified RNP showed in vivo genome editing ability, as well as in vitro endonuclease activity that combines with an unexpected superior stability to enable routine uses in molecular cloning instead of restriction enzymes. We further develop a RNP-based PCR-free method termed Cas-Brick in a one-step or cyclic way for seamless assembly of multiple DNA fragments with high fidelity up to 99%. Altogether, our findings provide a general strategy to prepare Cas9 RNP and supply a convenient and cost-effective DNA assembly method as an invaluable addition to synthetic biological toolboxes.

Prospective Function of Different Antioxidant Containing Natural Products in the Treatment of Neurodegenerative Disease

2020 ◽  
Vol 19 ◽  
Author(s):  
Md. Habibur Rahman ◽  
Rokeya Akter ◽  
Mohammad Amjad Kamal
Keyword(s):  
Natural Products ◽  
Large Scale ◽  
In Vivo Studies ◽  
Preclinical Models ◽  
Inflammatory Processes ◽  
Cognitive Actions ◽  
Neuro Protection ◽  
Neuronal Disorders

: Nature has bestowed humanity through additional resources natural products (NPs) on earth with water. However, NPs have a significant function in the avoidance of disease by boosting health in humans as well as animals. These NPs have been scientifically acknowledged to have a range of biological characteristics like antioxidant, anti-inflammatory actions. Both In vitro and in vivo studies have more recognised the convenience of NPs in different preclinical models of neurodegenerative disorders. Moreover, most NPs comprise phytoconstituents, including polyphenolic antioxidants; originate in herbs, fruits, nuts, vegetables as well as also in marine with freshwater flora. These phytoconstituents might actively repress neuro-degeneration and recover memory as like cognitive actions of the brain. Moreover, they are well recognized to participate in an essential position in the prevention like heal of different neurodegenerative diseases, like Alzheimer’s disease, Parkinson’s disease, epilepsy, and additional neuronal disorders. In general, the large-scale neuro-pharmacological actions of NPs have been familiar owing to the consequence of also the inhibition of inflammatory processes, or the up-regulation of various cell endurance proteins or a mixture of together. Owing to the shortage of human studies on neuroprotective belongings of NPs, this review highlights a variety of documented actions of NPs in vitro and in vivo preclinical models and their possible neuro-protection applications by the accessible awareness in writing.

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