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Microbiology (Reading, England) May 2019Members of the Gram-negative bacterial genus Photorhabdus are all highly insect pathogenic and exist in an obligate symbiosis with the entomopathogenic nematode worm...
Members of the Gram-negative bacterial genus Photorhabdus are all highly insect pathogenic and exist in an obligate symbiosis with the entomopathogenic nematode worm Heterorhabditis. All members of the genus produce the small-molecule 3,5-dihydroxy-4-isopropyl-trans-stilbene (IPS) as part of their secondary metabolism. IPS is a multi-potent compound that has antimicrobial, antifungal, immunomodulatory and anti-cancer activities and also plays an important role in symbiosis with the nematode. In this study we have examined the response of Photorhabdus itself to exogenous ectopic addition of IPS at physiologically relevant concentrations. We observed that the bacteria had a measureable phenotypic response, which included a decrease in bioluminescence and pigment production. This was reflected in changes in its transcriptomic response, in which we reveal a reduction in transcript levels of genes relating to many fundamental cellular processes, such as translation and oxidative phosphorylation. Our observations suggest that IPS plays an important role in the biology of Photorhabdus bacteria, fulfilling roles in quorum sensing, antibiotic-competition advantage and maintenance of the symbiotic developmental cycle.
Topics: Bacterial Proteins; Gene Expression Regulation, Bacterial; Oxidative Phosphorylation; Photorhabdus; Quorum Sensing; Secondary Metabolism; Stilbenes
PubMed: 30882293
DOI: 10.1099/mic.0.000790 -
Toxicon : Official Journal of the... Feb 2018The entomopathogenic Photorhabdus luminescens TT01 is a promoting bacterium that controls effectively many insect pests. Indeed, it exhibited a mortality rate of 32.36%...
The entomopathogenic Photorhabdus luminescens TT01 is a promoting bacterium that controls effectively many insect pests. Indeed, it exhibited a mortality rate of 32.36% against the first instar larvae of the turnip moth Agrotis segetum, when it was used at a concentration of 5 × 10 cells/ml but no toxicity against the second instar larvae in the same condition. P. luminescens TT01 oral toxicity is associated to septicaemia since cells fraction exhibited the highest mortality rate of 34%. In order to enhance P. luminescens TT01 insecticidal potential, combination with Bacillus thuringiensis Vip3Aa16 toxin was tested. An improvement of insecticidal activity was shown. Indeed, 100% mortality of A. segetum first instar larvae was obtained after 2 days of treatment, when using TT01 cells and Vip3Aa16 toxin at a concentration of 5 × 10 cells/ml and 9.025 ng/cm, respectively. Moreover, growth inhibition rate of 45% of the second instar larvae was observed, when using the same combination. A. segetum mortality could be the result of several alterations in the midgut epithelium caused by Vip3Aa16 toxin, allowing a rapid invasion of the hemocoel by TT01 cells as demonstrated by histopathological study. Clear symptoms of intoxication were observed for all combinations tested, including swelling, vesicle formation, cytoplasm vacuolization and brush border membrane lysis. Taken together, these results promote the use of P. luminescens TT01 as a potent bioinsecticide to control effectively A. segetum by oral treatment in a mixture with Vip3Aa16 toxin.
Topics: Animals; Bacterial Proteins; Insecticides; Larva; Moths; Photorhabdus
PubMed: 29305079
DOI: 10.1016/j.toxicon.2017.12.054 -
The Journal of Biological Chemistry Jun 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.
Topics: Glycosylation; Humans; Yersinia; Bacterial Proteins; Tyrosine; Glycosyltransferases; rhoA GTP-Binding Protein; Yersinia enterocolitica; Animals; HeLa Cells; Mice; Crystallography, X-Ray; Yersinia Infections
PubMed: 38703997
DOI: 10.1016/j.jbc.2024.107331 -
PloS One 2021Xenorhabdus and Photorhabdus are gram negative bacteria that can produce several secondary metabolites, including antimicrobial compounds. They have a symbiotic...
Xenorhabdus and Photorhabdus are gram negative bacteria that can produce several secondary metabolites, including antimicrobial compounds. They have a symbiotic association with entomopathogenic nematodes (EPNs). The aim of this study was to isolate and identify Xenorhabdus and Photorhabdus species and their associated nematode symbionts from Northeastern region of Thailand. We also evaluated the antibacterial activity of these symbiotic bacteria. The recovery rate of EPNs was 7.82% (113/1445). A total of 62 Xenorhabdus and 51 Photorhabdus strains were isolated from the EPNs. Based on recA sequencing and phylogeny, Xenorhabdus isolates were identified as X. stockiae (n = 60), X. indica (n = 1) and X. eapokensis (n = 1). Photorhabdus isolates were identified as P. luminescens subsp. akhurstii (n = 29), P. luminescens subsp. hainanensis (n = 18), P. luminescens subsp. laumondii (n = 2), and P. asymbiotica subsp. australis (n = 2). The EPNs based on 28S rDNA and internal transcribed spacer (ITS) analysis were identified as Steinernema surkhetense (n = 35), S. sangi (n = 1), unidentified Steinernema (n = 1), Heterorhabditis indica (n = 39), H. baujardi (n = 1), and Heterorhabditis sp. SGmg3 (n = 3). Antibacterial activity showed that X. stockiae (bMSK7.5_TH) extract inhibited several antibiotic-resistant bacterial strains. To the best of our knowledge, this is the first report on mutualistic association between P. luminescens subsp. laumondii and Heterorhabditis sp. SGmg3. This study could act as a platform for future studies focusing on the discovery of novel antimicrobial compounds from these bacterial isolates.
Topics: Animals; Anti-Bacterial Agents; Drug Resistance, Bacterial; Gram-Negative Bacteria; Gram-Positive Bacteria; Larva; Microbial Sensitivity Tests; Nematoda; Photorhabdus; Phylogeny; RNA, Ribosomal, 16S; RNA, Ribosomal, 28S; Soil; Soil Microbiology; Symbiosis; Xenorhabdus
PubMed: 34383819
DOI: 10.1371/journal.pone.0255943 -
Journal of Helminthology Sep 2021Liquid culture is the most scalable technology for the industrial production of entomopathogenic nematodes. Variability of the recovery after inoculation into cultures...
Liquid culture is the most scalable technology for the industrial production of entomopathogenic nematodes. Variability of the recovery after inoculation into cultures of Photorhabdus luminescens remains a persistent problem in the mass production of Heterorhabditis sp. In order to enhance infective juvenile (IJ) recovery and improve nematode population management, we analysed the correlation between the nematode Heterorhabditis megidis (strain KV - 136) development in liquid cultures, the density of bacteria of P. luminescens and the culture agitation speed. Analyses focused on the impact of different agitation speeds (160 rpm and 200 rpm) on the dynamics of population growth of H. megidis in liquid cultures at constant biotic and abiotic parameters (initial dose of nematodes introduced to the culture 2300 IJs/ml, temperature 25°C, the number of bacterial colonies 0.3 × 107/ml). The performed experiments showed that the agitation speed of 200 rpm favourably affected the density of bacteria of P. luminescens (24.14 × 107/ml). High density of bacteria at this agitation speed resulted in an earlier (on the fifth day of the culture) maximum increase in the number of hermaphroditic individuals (1239.6 H/ml) than in the culture at an agitation speed of 160 rpm.
Topics: Animals; Humans; Nematoda; Photorhabdus; Population Dynamics; Strongyloidea; Symbiosis
PubMed: 34505559
DOI: 10.1017/S0022149X21000493 -
Annals of the New York Academy of... Sep 2015Despite the importance of microbial natural products for human health, only a few bacterial genera have been mined for the new natural products needed to overcome the... (Review)
Review
Despite the importance of microbial natural products for human health, only a few bacterial genera have been mined for the new natural products needed to overcome the urgent threat of antibiotic resistance. This is surprising, given that genome sequencing projects have revealed that the capability to produce natural products is not a rare feature among bacteria. Even the bacteria occurring in the human microbiome produce potent antibiotics, and thus potentially are an untapped resource for novel compounds, potentially with new activities. This review highlights examples of bacteria that should be considered new sources of natural products, including anaerobes, pathogens, and symbionts of humans, insects, and nematodes. Exploitation of these producer strains, combined with advances in modern natural product research methodology, has the potential to open the way for a new golden age of microbial therapeutics.
Topics: Animals; Anti-Bacterial Agents; Bacteria; Bacterial Infections; Biological Products; Drug Resistance, Microbial; Humans; Insecta; Nematoda; Symbiosis
PubMed: 26509922
DOI: 10.1111/nyas.12954 -
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 -
Microbiology (Reading, England) Jun 2020Species of the bacterial genus live in a symbiotic relationship with entomopathogenic nematodes. Besides their use as biological control agents against agricultural...
Species of the bacterial genus live in a symbiotic relationship with entomopathogenic nematodes. Besides their use as biological control agents against agricultural pests, some species are also a source of natural products and are of medical interest due to their ability to cause tissue infections and subcutaneous lesions in humans. Given the diversity of species, rapid and reliable methods to resolve this genus to the species level are needed. In this study, we evaluated the potential of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of species. To this end, we established a collection of 54 isolates consisting of type strains and multiple field strains that belong to each of the validly described species and subspecies of this genus. Reference spectra for the strains were generated and used to complement a currently available database. The extended reference database was then used for identification based on the direct transfer sample preparation method and the protein fingerprint of single colonies. High-level discrimination of distantly related species was observed. However, lower discrimination was observed with some of the most closely related species and subspecies. Our results therefore suggest that MALDI-TOF MS can be used to correctly identify strains at the genus and species level, but has limited resolution power for closely related species and subspecies. Our study demonstrates the suitability and limitations of MALDI-TOF-based identification methods for assessment of the taxonomic position and identification of isolates.
Topics: Bacterial Typing Techniques; Humans; Photorhabdus; Phylogeny; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 32301690
DOI: 10.1099/mic.0.000905 -
PloS One 2020Xenorhabdus and Photorhabdus, symbiotically associated with entomopathogenic nematodes (EPNs), produce a range of antimicrobial compounds. The objective of this study is...
Xenorhabdus and Photorhabdus, symbiotically associated with entomopathogenic nematodes (EPNs), produce a range of antimicrobial compounds. The objective of this study is to identify Xenorhabdus and Photorhabdus and their EPNs hosts, which were isolated from soil samples from Saraburi province, and study their antibacterial activity against 15 strains of drug-resistant bacteria. Fourteen isolates (6.1%), consisting of six Xenorhabdus isolates and eight Photorhabdus isolates, were obtained from 230 soil samples. Based on the BLASTN search incorporating the phylogenetic analysis of a partial recA gene, all six isolates of Xenorhabdus were found to be identical and closely related to X. stockiae. Five isolates of Photorhabdus were found to be identical and closely related to P. luminescens subsp. akhurstii. Two isolates of Photorhabdus were found to be identical and closely related to P. luminescens subsp. hainanensis. The remaining isolate of Photorhabdus was found to be identical to P. asymbiotica subsp. australis. The bacterial extracts from P. luminescens subsp. akhurstii showed strong inhibition the growth of S. aureus strain PB36 (MSRA) by disk diffusion, minimal inhibitory concentration, and minimal bactericidal concentration assay. The combination between each extract from Xenorhabdus/Photorhabdus and oxacillin or vancomycin against S. aureus strain PB36 (MRSA) exhibited no interaction on checkerboard assay. Moreover, killing curve assay of P. luminescens subsp. akhurstii extracts against S. aureus strain PB36 exhibited a steady reduction of 105 CFU/ml to 103 CFU/ml within 30 min. This study demonstrates that Xenorhabdus and Photorhabdus, showed antibacterial activity. This finding may be useful for further research on antibiotic production.
Topics: Animals; Anti-Bacterial Agents; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Nematoda; Oxacillin; Photorhabdus; Phylogeny; Soil; Vancomycin; Xenorhabdus
PubMed: 32502188
DOI: 10.1371/journal.pone.0234129 -
Frontiers in Microbiology 2017Dam, the most described bacterial DNA-methyltransferase, is widespread in gamma-proteobacteria. Dam DNA methylation can play a role in various genes expression and is...
Dam, the most described bacterial DNA-methyltransferase, is widespread in gamma-proteobacteria. Dam DNA methylation can play a role in various genes expression and is involved in pathogenicity of several bacterial species. The purpose of this study was to determine the role played by the ortholog identified in the entomopathogenic bacterium . Complementation assays of an mutant showed the restoration of the DNA methylation state of the parental strain. Overexpression of in did not impair growth ability . In contrast, compared to a control strain harboring an empty plasmid, a significant decrease in motility was observed in the -overexpressing strain. A transcriptome analysis revealed the differential expression of 208 genes between the two strains. In particular, the downregulation of flagellar genes was observed in the -overexpressing strain. In the closely related bacterium overexpression also impaired motility. In addition, the -overexpressing strain showed a delayed virulence compared to that of the control strain after injection in larvae of the lepidopteran . These results reveal that Dam plays a major role during insect infection.
PubMed: 28919886
DOI: 10.3389/fmicb.2017.01671