scholarly journals Targeted Genome Mining Reveals the Psychrophilic Clostridium estertheticum Complex as a Potential Source for Novel Bacteriocins, Including Cesin A and Estercticin A

2022 ◽  
Vol 12 ◽  
Author(s):  
Joseph Wambui ◽  
Marc J. A. Stevens ◽  
Simon Sieber ◽  
Nicole Cernela ◽  
Vincent Perreten ◽  
...  

Antimicrobial resistance in pathogenic bacteria is considered a major public health issue necessitating the discovery of alternative antimicrobial compounds. In this regard, targeted genome mining in bacteria occupying under-explored ecological niches has the potential to reveal such compounds, including bacteriocins. In this study, we determined the bacteriocin biosynthetic potential of the psychrophilic Clostridium estertheticum complex (CEC) through a combination of genome mining and phenotypic screening assays. The genome mining was performed in 40 CEC genomes using antiSMASH. The production of bacteriocin-like compounds was phenotypically validated through agar well (primary screening) and disk diffusion (secondary screening) assays using cell free supernatants (CFS) and partially purified extracts, respectively. Stability of four selected CFS against proteolytic enzymes, temperature and pH was determined while one CFS was analyzed by HRMS and MS/MS to identify potential bacteriocins. Twenty novel bacteriocin biosynthetic gene clusters (BBGC), which were classified into eight (six lantibiotics and two sactipeptides) distinct groups, were discovered in 18 genomes belonging to C. estertheticum (n = 12), C. tagluense (n = 3) and genomospecies2 (n = 3). Primary screening linked six BBGC with narrow antimicrobial activity against closely related clostridia species. All four preselected CFS retained activity after exposure to different proteolytic, temperature and pH conditions. Secondary screening linked BBGC1 and BBGC7 encoding a lantibiotic and sactipeptide, respectively, with activity against Bacillus cereus while lantibiotic-encoding BBGC2 and BBGC3 were linked with activity against B. cereus, Staphylococcus aureus (methicillin-resistant), Escherichia coli and Pseudomonas aeruginosa. MS/MS analysis revealed that C. estertheticum CF004 produces cesin A, a short natural variant of nisin, and HRMS indicated the production of a novel sactipeptide named estercticin A. Therefore, we have shown the CEC, in particular C. estertheticum, is a source of novel and stable bacteriocins that have activities against clinically relevant pathogens.

2014 ◽  
Vol 58 (10) ◽  
pp. 6185-6196 ◽  
Author(s):  
Marius Spohn ◽  
Norbert Kirchner ◽  
Andreas Kulik ◽  
Angelika Jochim ◽  
Felix Wolf ◽  
...  

ABSTRACTThe emergence of antibiotic-resistant pathogenic bacteria within the last decades is one reason for the urgent need for new antibacterial agents. A strategy to discover new anti-infective compounds is the evaluation of the genetic capacity of secondary metabolite producers and the activation of cryptic gene clusters (genome mining). One genus known for its potential to synthesize medically important products isAmycolatopsis. However,Amycolatopsis japonicumdoes not produce an antibiotic under standard laboratory conditions. In contrast to mostAmycolatopsisstrains,A. japonicumis genetically tractable with different methods. In order to activate a possible silent glycopeptide cluster, we introduced a gene encoding the transcriptional activator of balhimycin biosynthesis, thebbrgene fromAmycolatopsis balhimycina(bbrAba), intoA. japonicum. This resulted in the production of an antibiotically active compound. Following whole-genome sequencing ofA. japonicum, 29 cryptic gene clusters were identified by genome mining. One of these gene clusters is a putative glycopeptide biosynthesis gene cluster. Using bioinformatic tools, ristomycin (syn. ristocetin), a type III glycopeptide, which has antibacterial activity and which is used for the diagnosis of von Willebrand disease and Bernard-Soulier syndrome, was deduced as a possible product of the gene cluster. Chemical analyses by high-performance liquid chromatography and mass spectrometry (HPLC-MS), tandem mass spectrometry (MS/MS), and nuclear magnetic resonance (NMR) spectroscopy confirmed thein silicoprediction that the recombinantA. japonicum/pRM4-bbrAbasynthesizes ristomycin A.


2021 ◽  
Author(s):  
Gerry Wright ◽  
Elizabeth Culp ◽  
David Sychantha ◽  
Christian Hobson ◽  
Andrew Pawlowski ◽  
...  

Abstract Intracellular proteolytic complexes play an essential role in modeling the proteome in both bacteria and eukaryotes. ClpP is the protease subunit of one such highly conserved proteolytic complex that, despite its potential, remains unexploited as a drug target. Here we describe a target-directed genome mining strategy to identify ClpP targeting compounds from the bacterial order Actinomycetales. By searching for biosynthetic gene clusters that contain duplicated copies of ClpP as putative antibiotic resistance genes, we identify a family of ClpP-associated clusters that are widespread across phyla, including environmental and pathogenic bacteria. While numerous bacterial pyrrolizidine alkaloids produced by these gene clusters are known, their connection to ClpP has never been made. We show that these previously characterized molecules do not affect ClpP function but are shunt metabolites derived from the genuine product of these gene clusters, a reactive covalent ClpP inhibitor. Focusing on one such cryptic gene cluster from Streptomyces cattleya DSM 46488, we use heterologous expression to purify the relevant ClpP inhibitor, which we name clipibicyclene. We show in vitro and in vivo that clipibicyclene is a potent covalent inhibitor of ClpP and that cluster-associated ClpPs provide resistance. ClpP inhibition results in antibacterial activity against actinobacteria, including Mycobacterium smegmatis, and inhibition of virulence factor production by Staphylococcus aureus. Finally, we solve the crystal structure of clipibicyclene-modified Escherichia coli ClpP. Clipibicyclene’s discovery deconvolutes the actual function of a family of natural products widespread in nature. It provides a novel scaffold for therapeutic ClpP inhibitor development, making these findings significant from the perspective of their discovery and their clinical potential.


Author(s):  
Léa Girard ◽  
Niels Geudens ◽  
Brent Pauwels ◽  
Monica Höfte ◽  
José C. Martins ◽  
...  

Pseudomonas lipopeptides (LPs) are involved in diverse ecological functions and have biotechnological potential associated with their antimicrobial and/or anti-proliferative activities. They are synthesized by multi-modular non-ribosomal peptide synthetases which, together with transport and regulatory proteins, are encoded by large biosynthetic gene clusters (BGCs). These secondary metabolites are classified in distinct families based on sequence and length of the oligopeptide, and size of the macrocycle, if present. Phylogeny of PleB, the MacB-like transporter that is part of a dedicated ATP-dependent tripartite efflux system driving export of Pseudomonas LPs, revealed a strong correlation with LP chemical diversity. As each LP BGC carries its cognate pleB , PleB is suitable as a diagnostic sequence for genome mining, allowing assignment of the putative metabolite to a particular LP family. In addition, pleB proved a suitable target gene for an alternative PCR method to detect LP-producing Pseudomonas , not relying on amplification of catalytic domains of the biosynthetic enzymes. Combined with amplicon sequencing, this approach enabled typing of Pseudomonas strains as potential producers of a LP belonging to one of ten different families, underscoring its value for strain prioritization. This was validated by chemical characterization of known LPs from three different families secreted by novel producers isolated from the rice or maize rhizosphere, namely the type strains of Pseudomonas fulva (putisolvin), Pseudomonas zeae (tensin) and Pseudomonas xantholysinigenes (xantholysin). In addition, a new member of the Bananamide family, prosekin, was discovered in the type strain of Pseudomonas prosekii , an Antarctic isolate. Importance Pseudomonas are ubiquitous bacteria able to thrive in a wide range of ecological niches and lipopeptides often support their lifestyle but also their interaction with other micro- and macro-organisms. Therefore, the production of lipopeptides is widespread among Pseudomonas strains. Consequently, Pseudomonas lipopeptide research affects not only chemists and microbiologists but touches a much broader audience, including biochemists, ecologists and plant biologists. In this study we present a reliable transporter gene-guided approach for the detection and/or typing of Pseudomonas lipopeptide producers. Indeed, it allows to readily assess the lipopeptide diversity among sets of Pseudomonas isolates and differentiate strains likely to produce known lipopeptides from producers of potentially novel lipopeptides. This work provides a valuable tool that can also be integrated in a genome mining strategy and adapted for the typing of other specialized metabolites.


mBio ◽  
2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Lee H. Bergstrand ◽  
Erick Cardenas ◽  
Johannes Holert ◽  
Jonathan D. Van Hamme ◽  
William W. Mohn

ABSTRACT Steroids are ubiquitous in natural environments and are a significant growth substrate for microorganisms. Microbial steroid metabolism is also important for some pathogens and for biotechnical applications. This study delineated the distribution of aerobic steroid catabolism pathways among over 8,000 microorganisms whose genomes are available in the NCBI RefSeq database. Combined analysis of bacterial, archaeal, and fungal genomes with both hidden Markov models and reciprocal BLAST identified 265 putative steroid degraders within only Actinobacteria and Proteobacteria , which mainly originated from soil, eukaryotic host, and aquatic environments. These bacteria include members of 17 genera not previously known to contain steroid degraders. A pathway for cholesterol degradation was conserved in many actinobacterial genera, particularly in members of the Corynebacterineae , and a pathway for cholate degradation was conserved in members of the genus Rhodococcus . A pathway for testosterone and, sometimes, cholate degradation had a patchy distribution among Proteobacteria . The steroid degradation genes tended to occur within large gene clusters. Growth experiments confirmed bioinformatic predictions of steroid metabolism capacity in nine bacterial strains. The results indicate there was a single ancestral 9,10-seco-steroid degradation pathway. Gene duplication, likely in a progenitor of Rhodococcus , later gave rise to a cholate degradation pathway. Proteobacteria and additional Actinobacteria subsequently obtained a cholate degradation pathway via horizontal gene transfer, in some cases facilitated by plasmids. Catabolism of steroids appears to be an important component of the ecological niches of broad groups of Actinobacteria and individual species of Proteobacteria . IMPORTANCE Steroids are ubiquitous growth substrates for environmental and pathogenic bacteria, and bacterial steroid metabolism has important pharmaceutical and health applications. To date, the genetics and biochemistry of microbial steroid degradation have mainly been studied in a few model bacteria, and the diversity of this metabolism remains largely unexplored. Here, we provide a bioinformatically derived perspective of the taxonomic distribution of aerobic microbial steroid catabolism pathways. We identified several novel steroid-degrading bacterial groups, including ones from marine environments. In several cases, we confirmed bioinformatic predictions of metabolism in cultures. We found that cholesterol and cholate catabolism pathways are highly conserved among certain actinobacterial taxa. We found evidence for horizontal transfer of a pathway to several proteobacterial genera, conferring testosterone and, sometimes, cholate catabolism. The results of this study greatly expand our ecological and evolutionary understanding of microbial steroid metabolism and provide a basis for better exploiting this metabolism for biotechnology.


2021 ◽  
Author(s):  
xinyang du ◽  
Huanhuan Li ◽  
Jiangfeng Qi ◽  
Chaoyi Chen ◽  
Yuanyuan Lu ◽  
...  

Abstract As an important saprophytic filamentous fungus, Aspergillus terreus is ubiquitously distributed, including soil rhizospheres and marine environments. Due to the prominent capabilities of bioconversion and biosynthesis, A. terreus has become attractive in biotechnical and pharmaceutical industry. In this work, an A. terreus strain, B12, was isolated from sponge in South China Sea, which demonstrated broad bacteriostatic effects against a variety of pathogenic bacteria. The whole genome was sequenced, showing a genetic richness of BGCs, which might underpin the metabolic plasticity and adaptive resilience for the strain. Genome mining identified 67 biosynthetic gene clusters (BGCs), among which, 6 gene clusters could allocate to known BGCs (100% identity), corresponding to diverse metabolites like clavaric acid, dihydroisoflavipucine /isoflavipucine, dimethylcoprogen, alternariol, aspterric acid and pyranonigrin E. However, instead of the putative compounds, several other products were obtained from the B12 fermentation, including terrein, butyrolactone I, terretonin A&E, acoapetaline B and epi-aszonalenins A. Of note, acoapetaline B and epi-aszonalenins A, discovered natural products recently with little information, unexpectedly were reported in this A. terreus strain. The genomic and heterogeneity observed in strain B12, should be at least partially attributed to the genetic variability and biochemical diversity of A. terreus , which could be an interesting issue open to future efforts.


Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 144
Author(s):  
Jason Stahlecker ◽  
Erik Mingyar ◽  
Nadine Ziemert ◽  
Mehmet Direnç Mungan

The development of new antibacterial drugs has become one of the most important tasks of the century in order to overcome the posing threat of drug resistance in pathogenic bacteria. Many antibiotics originate from natural products produced by various microorganisms. Over the last decades, bioinformatical approaches have facilitated the discovery and characterization of these small compounds using genome mining methodologies. A key part of this process is the identification of the most promising biosynthetic gene clusters (BGCs), which encode novel natural products. In 2017, the Antibiotic Resistant Target Seeker (ARTS) was developed in order to enable an automated target-directed genome mining approach. ARTS identifies possible resistant target genes within antibiotic gene clusters, in order to detect promising BGCs encoding antibiotics with novel modes of action. Although ARTS can predict promising targets based on multiple criteria, it provides little information about the cluster structures of possible resistant genes. Here, we present SYN-view. Based on a phylogenetic approach, SYN-view allows for easy comparison of gene clusters of interest and distinguishing genes with regular housekeeping functions from genes functioning as antibiotic resistant targets. Our aim is to implement our proposed method into the ARTS web-server, further improving the target-directed genome mining strategy of the ARTS pipeline.


Author(s):  
Patrick Videau ◽  
Kaitlyn Wells ◽  
Arun Singh ◽  
Jessie Eiting ◽  
Philip Proteau ◽  
...  

Cyanobacteria are prolific producers of natural products and genome mining has shown that many orphan biosynthetic gene clusters can be found in sequenced cyanobacterial genomes. New tools and methodologies are required to investigate these biosynthetic gene clusters and here we present the use of <i>Anabaena </i>sp. strain PCC 7120 as a host for combinatorial biosynthesis of natural products using the indolactam natural products (lyngbyatoxin A, pendolmycin, and teleocidin B-4) as a test case. We were able to successfully produce all three compounds using codon optimized genes from Actinobacteria. We also introduce a new plasmid backbone based on the native <i>Anabaena</i>7120 plasmid pCC7120ζ and show that production of teleocidin B-4 can be accomplished using a two-plasmid system, which can be introduced by co-conjugation.


2021 ◽  
Author(s):  
Valentin Waschulin ◽  
Chiara Borsetto ◽  
Robert James ◽  
Kevin K. Newsham ◽  
Stefano Donadio ◽  
...  

AbstractThe growing problem of antibiotic resistance has led to the exploration of uncultured bacteria as potential sources of new antimicrobials. PCR amplicon analyses and short-read sequencing studies of samples from different environments have reported evidence of high biosynthetic gene cluster (BGC) diversity in metagenomes, indicating their potential for producing novel and useful compounds. However, recovering full-length BGC sequences from uncultivated bacteria remains a challenge due to the technological restraints of short-read sequencing, thus making assessment of BGC diversity difficult. Here, long-read sequencing and genome mining were used to recover >1400 mostly full-length BGCs that demonstrate the rich diversity of BGCs from uncultivated lineages present in soil from Mars Oasis, Antarctica. A large number of highly divergent BGCs were not only found in the phyla Acidobacteriota, Verrucomicrobiota and Gemmatimonadota but also in the actinobacterial classes Acidimicrobiia and Thermoleophilia and the gammaproteobacterial order UBA7966. The latter furthermore contained a potential novel family of RiPPs. Our findings underline the biosynthetic potential of underexplored phyla as well as unexplored lineages within seemingly well-studied producer phyla. They also showcase long-read metagenomic sequencing as a promising way to access the untapped genetic reservoir of specialised metabolite gene clusters of the uncultured majority of microbes.


2020 ◽  
Vol 105 (12) ◽  
pp. 1175-1179
Author(s):  
Daniel Wenger ◽  
Carl Johan Tiderius ◽  
Henrik Düppe

ObjectivesTo quantify the effect of secondary screening for hip dislocations.DesignRetrospective analysis of hospital files from participants in a prospectively collected nationwide registry.SettingChild healthcare centres and orthopaedic departments in Sweden.ParticipantsOf 126 children with hip dislocation diagnosed later than 14 days age in the 2000–2009 birth cohort, 101 had complete data and were included in the study.InterventionsThe entire birth cohort was subject to clinical screening for hip instability at 6–8 weeks, 6 months and 10–12 months age. Children diagnosed through this screening were compared with children presenting due to symptoms, which was used as a surrogate variable representing a situation without secondary screening.Main outcome measuresAge at diagnosis and disease severity of late presenting hip dislocations.ResultsChildren diagnosed through secondary screening were 11 months younger (median: 47 weeks) compared with those presenting with symptoms (p<0.001). Children diagnosed through secondary screening had 11% risk of having a high (severe) dislocation, compared with 38% for those diagnosed due to symptoms; absolute risk reduction 27% (95% CI: 9.7% to 45%), relative risk 0.28 (95% CI: 0.11 to 0.70). Children presenting due to symptoms had OR 5.1 (95% CI: 1.7 to 15) of having a high dislocation, and OR 11 (95% CI: 4.1 to 31) of presenting at age 1 year or older, compared with the secondary screening group. The secondary screening was able to identify half of the children (55%, 95% CI: 45% to 66%) not diagnosed through primary screening.ConclusionsSecondary screening at child healthcare centres may have substantially lowered the age at diagnosis in half of all children with late presenting hip dislocation not diagnosed through primary screening, with the risk of having a high dislocation decreased almost to one-quarter in such cases.


2019 ◽  
Vol 7 (4) ◽  
pp. 101 ◽  
Author(s):  
Sabina Zoledowska ◽  
Luana Presta ◽  
Marco Fondi ◽  
Francesca Decorosi ◽  
Luciana Giovannetti ◽  
...  

Understanding plant–microbe interactions is crucial for improving plants’ productivity and protection. Constraint-based metabolic modeling is one of the possible ways to investigate the bacterial adaptation to different ecological niches and may give insights into the metabolic versatility of plant pathogenic bacteria. We reconstructed a raw metabolic model of the emerging plant pathogenic bacterium Pectobacterium parmentieri SCC3193 with the use of KBase. The model was curated by using inParanoind and phenotypic data generated with the use of the OmniLog system. Metabolic modeling was performed through COBRApy Toolbox v. 0.10.1. The curated metabolic model of P. parmentieri SCC3193 is highly reliable, as in silico obtained results overlapped up to 91% with experimental data on carbon utilization phenotypes. By mean of flux balance analysis (FBA), we predicted the metabolic adaptation of P. parmentieri SCC3193 to two different ecological niches, relevant for the persistence and plant colonization by this bacterium: soil and the rhizosphere. We performed in silico gene deletions to predict the set of essential core genes for this bacterium to grow in such environments. We anticipate that our metabolic model will be a valuable element for defining a set of metabolic targets to control infection and spreading of this plant pathogen.


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