-
Ecology and Evolution Feb 2024Understanding how parasites evolved is crucial to understand the host and parasite interaction. The evolution of entomopathogenesis in rhabditid nematodes has... (Review)
Review
Understanding how parasites evolved is crucial to understand the host and parasite interaction. The evolution of entomopathogenesis in rhabditid nematodes has traditionally been thought to have occurred twice within the phylum Nematoda: in Steinernematidae and Heterorhabditidae families, which are associated with the entomopathogenic bacteria and , respectively. However, nematodes from other families that are associated with entomopathogenic bacteria have not been considered to meet the criteria for "entomopathogenic nematodes." The evolution of parasitism in nematodes suggests that ecological and evolutionary properties shared by families in the order Rhabditida favor the convergent evolution of the entomopathogenic trait in lineages with diverse lifestyles, such as saprotrophs, phoretic, and necromenic nematodes. For this reason, this paper proposes expanding the term "entomopathogenic nematode" considering the diverse modes of this attribute within Rhabditida. Despite studies are required to test the authenticity of the entomopathogenic trait in the reported species, they are valuable links that represent the early stages of specialized lineages to entomopathogenic lifestyle. An ecological and evolutionary exploration of these nematodes has the potential to deepen our comprehension of the evolution of entomopathogenesis as a convergent trait spanning across the Nematoda.
PubMed: 38352205
DOI: 10.1002/ece3.10966 -
Cell Chemical Biology Aug 2023Darobactins represent a class of ribosomally synthesized and post-translationally modified peptide (RiPP) antibiotics featuring a rare bicyclic structure. They target...
Darobactins represent a class of ribosomally synthesized and post-translationally modified peptide (RiPP) antibiotics featuring a rare bicyclic structure. They target the Bam-complex of Gram-negative bacteria and exhibit in vivo activity against drug-resistant pathogens. First isolated from Photorhabdus species, the corresponding biosynthetic gene clusters (BGCs) are widespread among γ-proteobacteria, including the genera Vibrio, Yersinia, and Pseudoalteromonas (P.). While the organization of the BGC core is highly conserved, a small subset of Pseudoalteromonas carries an extended BGC with additional genes. Here, we report the identification of brominated and dehydrated darobactin derivatives from P. luteoviolacea strains. The marine derivatives are active against multidrug-resistant (MDR) Gram-negative bacteria and showed solubility and plasma protein binding ability different from darobactin A, rendering it more active than darobactin A. The halogenation reaction is catalyzed by DarH, a new class of flavin-dependent halogenases with a novel fold.
Topics: Phenylpropionates; Gram-Negative Bacteria; Metabolome
PubMed: 37451267
DOI: 10.1016/j.chembiol.2023.06.011 -
Journal of Applied Microbiology Jun 2024This study aimed to overproduce industrially relevant and safe bio-compound trans-cinnamic acid (tCA) from Photorhabdus luminescens with deletion strategies and...
AIM
This study aimed to overproduce industrially relevant and safe bio-compound trans-cinnamic acid (tCA) from Photorhabdus luminescens with deletion strategies and homologous expression strategies that had not been applied before for tCA production.
METHODS AND RESULTS
The overproduction of the industrially relevant compound tCA was successfully performed in Photorhabdus luminescens by deleting stlB (TTO1ΔstlB) encoding a cinnamic acid CoA ligase in the isopropylstilbene pathway and the hcaE insertion (knockout) mutation (hcaE:: cat) in the phenylpropionate catabolic pathway, responsible for tCA degradation. A double mutant of both stlB deletion and hcaE insertion mutation (TTO1DM ΔstlB-hcaE:: cat) was also generated. These deletion strategies and the phenylalanine ammonium lyase-producing (PI-PAL from Photorhabdus luminescens) plasmid, pBAD30C, carrying stlA (homologous expression mutants) are utilized together in the same strain using different media, a variety of cultivation conditions, and efficient anion exchange resin (Amberlite IRA402) for enhanced tCA synthesis. At the end of the 120-hour shake flask cultivation, the maximum tCA production was recorded as 1281 mg L-1 in the TTO1pBAD30C mutant cultivated in TB medium, with the IRA402 resin keeping 793 mg L-1 and the remaining 488 mg L-1 found in the supernatant.
CONCLUSION AND IMPACT OF THE STUDY
tCA production was successfully achieved with homologous expression, coupled with deletion and insertion strategies. 1281 mg L-1is the highest tCA concentration that achieved by bacterial tCA production in flask cultivation, according to our knowledge. IRA402 resin adsorbers seem useful for enhancing tCA acquisition in bacterial cultures. Mutations on the hcaE and stlB genes clearly increased the amount of tCA. P. luminescens is an effective bacterial candidate to produce tCA in industrial applications with the implemented strategies.
PubMed: 38906846
DOI: 10.1093/jambio/lxae149 -
Frontiers in Insect Science 2023The term "microbial control" has been used to describe the use of microbial pathogens (bacteria, viruses, or fungi) or entomopathogenic nematodes (EPNs) to control... (Review)
Review
The term "microbial control" has been used to describe the use of microbial pathogens (bacteria, viruses, or fungi) or entomopathogenic nematodes (EPNs) to control various insect pest populations. EPNs are among the best biocontrol agents, and major developments in their use have occurred in recent decades, with many surveys having been conducted all over the world to identify EPNs that may have potential in the management of insect pests. For nematodes, the term "entomopathogenic" means "causing disease to insects" and is mainly used in reference to the bacterial symbionts of and ( and , respectively), which cause EPN infectivity. A compendium of our multiannual experiences on EPN surveys and on their collection, identification, characterization, and use in agro-forestry ecosystems is presented here to testify and demonstrate once again that biological control with EPNs is possible and offers many advantages over chemicals, such as end-user safety, minimal damage to natural enemies, and lack of environmental pollution, which are essential conditions for an advanced IPM strategy.
PubMed: 38469514
DOI: 10.3389/finsc.2023.1195254 -
The Journal of Biological Chemistry May 2024Mono-O-glycosylation of target proteins by bacterial toxins or effector proteins is a well-known mechanism by which bacteria interfere with essential functions of host...
Mono-O-glycosylation of target proteins by bacterial toxins or effector proteins is a well-known mechanism by which bacteria interfere with essential functions of host cells. The respective glycosyltransferases are important virulence factors such as the Clostridioides difficile toxins A and B. Here, we describe two glycosyltransferases of Yersinia species that have a high sequence identity: YeGT from the zoonotic pathogen Yersinia enterocolitica and YkGT from the murine pathogen Yersinia kristensenii. We show that both modify Rho family proteins by attachment of GlcNAc at tyrosine residues (Tyr-34 in RhoA). Notably, the enzymes differed in their target protein specificity. While YeGT modified RhoA, B, and C, YkGT possessed a broader substrate spectrum and glycosylated not only Rho but also Rac and Cdc42 subfamily proteins. Mutagenesis studies indicated that residue 177 is important for this broader target spectrum. We determined the crystal structure of YeGT shortened by 16 residues N terminally (sYeGT) in the ligand-free state and bound to UDP, the product of substrate hydrolysis. The structure assigns sYeGT to the GT-A family. It shares high structural similarity to glycosyltransferase domains from toxins. We also demonstrated that the 16 most N-terminal residues of YeGT and YkGT are important for the mediated translocation into the host cell using the pore-forming protective antigen of anthrax toxin. Mediated introduction into HeLa cells or ectopic expression of YeGT and YkGT caused morphological changes and redistribution of the actin cytoskeleton. The data suggest that YeGT and YkGT are likely bacterial effectors belonging to the family of tyrosine glycosylating bacterial glycosyltransferases.
PubMed: 38703997
DOI: 10.1016/j.jbc.2024.107331 -
Biochemical Pharmacology Feb 2024Photorhabdus luminescens is a gram-negative bioluminescent bacterium known as an intestinal bacterium that coexists in the digestive tract of insect-pathogenic...
Photorhabdus luminescens is a gram-negative bioluminescent bacterium known as an intestinal bacterium that coexists in the digestive tract of insect-pathogenic nematodes. As part of our ongoing exploration to identify bioactive compounds from diverse natural resources, the chemical analysis of the cultures of P. luminescens KACC 12254 via LC/MS and TLC-based analyses enabled the isolation and identification of a major fluorescent compound. Its chemical structure was elucidated as 1,8-dihydroxy-3-methoxyanthraquinone (DMA) using HR-ESI-MS and NMR analysis. In this study, we conducted comprehensive investigations utilizing human colorectal cancer HCT116 cells, human umbilical cord vascular endothelial cells (HUVECs), and zebrafish embryos to assess the potential benefits of DMA in suppressing tumor angiogenesis. Our results convincingly demonstrate that DMA effectively suppresses the stability of hypoxia-inducible factor-1α (HIF-1α) protein and its target genes without inducing any cytotoxic effects. Furthermore, DMA demonstrates the ability to inhibit HIF-1α transcriptional activation and mitigate the production of reactive oxygen species (ROS). In our in vitro experiments, DMA exhibits notable inhibitory effects on VEGF-mediated tube formation, migration, and invasion in HUVECs. Additionally, in vivo investigations using zebrafish embryos confirm the antiangiogenic properties of DMA. Notably, DMA does not exhibit any adverse developmental or cardiotoxic effects in the in vivo setting. Moreover, we observe DMA's capability to restrain tumor growth through the downregulation of PI3K/AKT and c-RAF/ERK pathway. Collectively, these compelling findings underscore DMA's potential as a promising therapeutic candidate for targeted intervention against HIF-1α and angiogenesis in cancer treatment.
Topics: Animals; Humans; Angiogenesis; Anthraquinones; Cell Line, Tumor; Down-Regulation; Endothelial Cells; Hypoxia-Inducible Factor 1, alpha Subunit; Neovascularization, Pathologic; Phosphatidylinositol 3-Kinases; Signal Transduction; Zebrafish
PubMed: 38072164
DOI: 10.1016/j.bcp.2023.115972 -
Pathogens (Basel, Switzerland) Aug 2023Vector-borne diseases pose a severe threat to human and animal health. L. (Diptera: Culicidae) is a widespread mosquito species and serves as a vector for the...
Vector-borne diseases pose a severe threat to human and animal health. L. (Diptera: Culicidae) is a widespread mosquito species and serves as a vector for the transmission of infectious diseases such as West Nile disease and Lymphatic Filariasis. Synthetic insecticides have been the prime control method for many years to suppress populations. However, recently, the use of insecticides has begun to be questioned due to the detrimental impact on human health and the natural environment. Therefore, many authorities urge the development of eco-friendly control methods that are nontoxic to humans. The bacterial associates [ and spp. (Enterobacterales: Morganellaceae)] of entomopathogenic nematodes (EPNs) ( spp. and spp.) (Rhabditida: Heterorhabditidae and Steinernematidae) are one of the green approaches to combat a variety of insect pests. In the present study, the mosquitocidal activity of the cell-free supernatants and cell suspension (4 × 10 cells mL) of four different symbiotic bacteria (, , , and subsp. ) was assessed against different development stages of (The 1st/2nd and 3rd/4th instar larvae and pupa) under laboratory conditions. The bacterial symbionts were able to kill all the development stages with varying levels of mortality. The 1st/2nd instar larvae exhibited the highest susceptibility to the cell-free supernatants and cell suspensions of symbiotic bacteria and the efficacy of the cell-free supernatants and cell suspensions gradually declined with increasing phases of growth. The highest effectiveness was achieved by the KCS-4S strain inducing 95% mortality to the 1st/2nd instar larvae. The results indicate that tested bacterial symbionts have great potential as an eco-friendly alternative to insecticides.
PubMed: 37764903
DOI: 10.3390/pathogens12091095 -
Frontiers in Microbiology 2023Contractile injection systems (CISs) are phage tail-related structures that are encoded in many bacterial genomes. These devices encompass the cell-based type VI... (Review)
Review
Contractile injection systems (CISs) are phage tail-related structures that are encoded in many bacterial genomes. These devices encompass the cell-based type VI secretion systems (T6SSs) as well as extracellular CISs (eCISs). The eCISs comprise the R-tailocins produced by various bacterial species as well as related phage tail-like structures such as the antifeeding prophages (Afps) of , the virulence cassettes (PVCs), and the metamorphosis-associated contractile structures (MACs) of . These contractile structures are released into the extracellular environment upon suicidal lysis of the producer cell and play important roles in bacterial ecology and evolution. In this review, we specifically portray the eCISs with a focus on the R-tailocins, sketch the history of their discovery and provide insights into their evolution within the bacterial host, their structures and how they are assembled and released. We then highlight ecological and evolutionary roles of eCISs and conceptualize how they can influence and shape bacterial communities. Finally, we point to their potential for biotechnological applications in medicine and agriculture.
PubMed: 37886057
DOI: 10.3389/fmicb.2023.1264877 -
Microbial Cell Factories Apr 2024Bacteria of the genus Photorhabdus and Xenorhabdus are motile, Gram-negative bacteria that live in symbiosis with entomopathogenic nematodes. Due to their complex life...
BACKGROUND
Bacteria of the genus Photorhabdus and Xenorhabdus are motile, Gram-negative bacteria that live in symbiosis with entomopathogenic nematodes. Due to their complex life cycle, they produce a large number of specialized metabolites (natural products) encoded in biosynthetic gene clusters (BGC). Genetic tools for Photorhabdus and Xenorhabdus have been rare and applicable to only a few strains. In the past, several tools have been developed for the activation of BGCs and the deletion of individual genes. However, these often have limited efficiency or are time consuming. Among the limitations, it is essential to have versatile expression systems and genome editing tools that could facilitate the practical work.
RESULTS
In the present study, we developed several expression vectors and a CRISPR-Cpf1 genome editing vector for genetic manipulations in Photorhabdus and Xenorhabdus using SEVA plasmids. The SEVA collection is based on modular vectors that allow exchangeability of different elements (e.g. origin of replication and antibiotic selection markers with the ability to insert desired sequences for different end applications). Initially, we tested different SEVA vectors containing the broad host range origins and three different resistance genes for kanamycin, gentamycin and chloramphenicol, respectively. We demonstrated that these vectors are replicative not only in well-known representatives, e.g. Photorhabdus laumondii TTO1, but also in other rarely described strains like Xenorhabdus sp. TS4. For our CRISPR/Cpf1-based system, we used the pSEVA231 backbone to delete not only small genes but also large parts of BGCs. Furthermore, we were able to activate and refactor BGCs to obtain high production titers of high value compounds such as safracin B, a semisynthetic precursor for the anti-cancer drug ET-743.
CONCLUSIONS
The results of this study provide new inducible expression vectors and a CRISPR/CPf1 encoding vector all based on the SEVA (Standard European Vector Architecture) collection, which can improve genetic manipulation and genome editing processes in Photorhabdus and Xenorhabdus.
Topics: Xenorhabdus; Photorhabdus; Gene Editing; Biological Products; Clustered Regularly Interspaced Short Palindromic Repeats
PubMed: 38561780
DOI: 10.1186/s12934-024-02363-8 -
Scientific Reports Nov 2023The discovery of novel bioactive compounds produced by microorganisms holds significant potential for the development of therapeutics and agrochemicals. In this study,...
The discovery of novel bioactive compounds produced by microorganisms holds significant potential for the development of therapeutics and agrochemicals. In this study, we conducted genome mining to explore the biosynthetic potential of entomopathogenic bacteria belonging to the genera Xenorhabdus and Photorhabdus. By utilizing next-generation sequencing and bioinformatics tools, we identified novel biosynthetic gene clusters (BGCs) in the genomes of the bacteria, specifically plu00736 and plu00747. These clusters were identified as unidentified non-ribosomal peptide synthetase (NRPS) and unidentified type I polyketide synthase (T1PKS) clusters. These BGCs exhibited unique genetic architecture and encoded several putative enzymes and regulatory elements, suggesting its involvement in the synthesis of bioactive secondary metabolites. Furthermore, comparative genome analysis revealed that these BGCs were distinct from previously characterized gene clusters, indicating the potential for the production of novel compounds. Our findings highlighted the importance of genome mining as a powerful approach for the discovery of biosynthetic gene clusters and the identification of novel bioactive compounds. Further investigations involving expression studies and functional characterization of the identified BGCs will provide valuable insights into the biosynthesis and potential applications of these bioactive compounds.
Topics: Genome, Bacterial; Bacteria; Computational Biology; Multigene Family; Biosynthetic Pathways
PubMed: 38007490
DOI: 10.1038/s41598-023-47121-9