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Biotechnology Letters Oct 2018Gram-negative bacilli such as Pseudomonas spp., Pseudoalteromonas sp., Angiococcus sp., Archangium sp., Burkholderia spp., Chromobacterium sp., Chondromyces sp.,... (Review)
Review
Gram-negative bacilli such as Pseudomonas spp., Pseudoalteromonas sp., Angiococcus sp., Archangium sp., Burkholderia spp., Chromobacterium sp., Chondromyces sp., Cystobacter sp., Jahnella sp., Janthinobacterium sp., Lysobacter spp., Paraliomyxa sp., Photobacterium spp., Photorhabdus sp., Pontibacter sp., Ruegeria sp., Serratia sp., Sorangium sp., Sphingomonas sp., and Xenorhabdus spp. produce an enormous array of short peptides of 30 residues or fewer that are potential pharmaceutical drugs and/or biocontrol agents. The need for novel lead antibiotic compounds is urgent due to increasing drug resistance, and this review summarises 150 Gram-negative bacilli-derived compounds reported since 2000, including 40 cyclic lipopeptides from Pseudomonas spp.; nine aromatic peptides; eight glycopeptides; 45 different cyclic lipopeptides; 24 linear lipopeptides; eight thiopeptides; one lasso peptide; ten typical cyclic peptides; and five standard linear peptides. The current and potential therapeutic applications of these peptides, including structures and antituberculotic, anti-cyanobacterial, antifungal, antibacterial, antiviral, insecticidal, and antiprotozoal activities are discussed.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Drug Evaluation, Preclinical; Gram-Negative Bacteria; Lipopeptides; Microbial Sensitivity Tests; Peptides; Peptides, Cyclic
PubMed: 29968134
DOI: 10.1007/s10529-018-2589-1 -
Pakistan Journal of Biological Sciences... Jun 2022<b>Background and Objective:</b> The housefly poses a threat to the public health of humans and domestic animals since it can carry and transmit pathogens....
<b>Background and Objective:</b> The housefly poses a threat to the public health of humans and domestic animals since it can carry and transmit pathogens. Despite there are many attempts to control this insect, most of them depend on conventional pesticides. Thus, the current study aimed to evaluate the efficacy of whole-cell suspension, cell-free supernatant and crude cells of the symbiotic bacteria <i>Photorhabdus</i> sp. and <i>Xenorhabdus</i> sp., as bio-control agents for housefly stages. <b>Materials and Methods:</b> The <i>Photorhabdus</i> sp. and <i>Xenorhabdus</i> sp., were isolated from the entomopathogenic nematodes, <i>Heterorhabditis indica</i> and <i>Steinernema feltiae</i>, respectively. The phenotypic, as well as the enzymatic characterizations of both bacteria, were determined. In addition, histopathological changes of the alimentary canal of <i>M. domestica</i> adults treated with whole-cell suspensions (at 3×10<sup>8 </sup>cells mL<sup></sup><sup>1</sup>) of both bacteria were carefully examined using transmission electron microscopy. <b>Results:</b> The results showed that both symbiotic bacteria significantly suppressed larvae, pupae and adults of <i>M. domestica</i>, particularly when they were applied as whole-cell suspensions. For example, the highest concentration of whole-cell suspension, cell-free supernatant and crude cells of <i>Photorhabdus</i> sp., induced larval mortalities by 94.7, 64.0 and 45.3%, while those of <i>Xenorhabdus</i> sp., induced larval mortalities by 58.7, 46.7 and 30.7% at 96 hrs, respectively. The results also showed that whole-cell suspensions of both symbiotic bacteria caused severe histopathological changes in the ultrastructure of the treated adults' alimentary canal. <b>Conclusion:</b> Both symbiotic bacteria can be effectively used, particularly the whole-cell suspension, as bio-control agents against the housefly either in the larval or adult stage.
Topics: Animals; Houseflies; Humans; Larva; Nematoda; Photorhabdus; Symbiosis; Xenorhabdus
PubMed: 36098165
DOI: 10.3923/pjbs.2022.586.601 -
Trends in Microbiology Oct 2018Members of the genera Xenorhabdus and Photorhabdus are capable of producing a huge repertoire of different natural products to support a complex life cycle involving... (Review)
Review
Members of the genera Xenorhabdus and Photorhabdus are capable of producing a huge repertoire of different natural products to support a complex life cycle involving insect pathogenesis and nematode symbiosis. Many of the natural products have direct functions, specifically targeting different facets of nematode development or the insect immune system. These adaptations have allowed the bacteria to thrive in a unique environment and become highly efficient, versatile insect pathogens. Here, we discuss the ecological advantages afforded to the bacteria by the acquisition of the gene clusters responsible for producing this repertoire of chemical compounds.
Topics: Animals; Host-Pathogen Interactions; Insecta; Multigene Family; Nematoda; Photorhabdus; Symbiosis; Xenorhabdus
PubMed: 29801772
DOI: 10.1016/j.tim.2018.04.007 -
3 Biotech May 2017Five bacterial strains were isolated from the hemocoel of the greater wax moth larvae (Galleria mellonella) infected with the entomopathogenic nematodes: Heterorhabditis...
Five bacterial strains were isolated from the hemocoel of the greater wax moth larvae (Galleria mellonella) infected with the entomopathogenic nematodes: Heterorhabditis bacteriophora HP88, Heterorhabditis indicus RM1 and Heterorhabditis sp (S1), Steinernema abbasi and Steinernema sp. (S II). Strains were identified as Photorhabdus luminescens HRM1, P. luminescens HS1, P. luminescens HP88, Xenorhabdus indica and X. nematophila ATTC19061 using 16S rDNA sequence analysis. To reveal the genetic diversity among these strains, three molecular markers (RAPD, ISSR and SRAP) were employed. RAPD analysis showed 73.8 and 54.5 polymorphism percentages for the Photorhabdus and Xenorhabdus strains, respectively. ISSR analysis resulted in 70.1 and 75.2 polymorphism percentages among the Photorhabdus and Xenorhabdus strains, respectively. The SRAP analysis indicated that 75.6 and 61.2% genetic polymorphism was detected among Photorhabdus and Xenorhabdus strains, respectively. The cluster analysis grouped the three Photorhabdus strains together in one cluster and the two Xenorhabdus strains together in another cluster indicating the phylogenetic relationships among them. The genotype-specific markers detected from the three molecular markers (RAPD, ISSR and SRAP) were sufficient to distinguish between the different bacterial strains tested and can be used in the future IBM program that could be built on the use of these strains.
PubMed: 28391470
DOI: 10.1007/s13205-016-0594-4 -
International Journal of Systematic and... May 2023Six Gram-negative, rod-shaped bacterial strains isolated from entomopathogenic nematodes were characterized to determine their taxonomic position. 16S rRNA and gene...
Six Gram-negative, rod-shaped bacterial strains isolated from entomopathogenic nematodes were characterized to determine their taxonomic position. 16S rRNA and gene sequences indicate that they belong to the class , family and genus , and that some of them are conspecifics. Two of them, APURE and JAR, were selected for further molecular characterization using whole genome- and whole-proteome-based phylogenetic reconstructions and sequence comparisons. Phylogenetic reconstructions using whole genome and whole proteome sequences show that strains APURE and JAR are closely related to subsp. ATCC 29999 and to subsp. MEX47-22. Moreover, digital DNA-DNA hybridization (dDDH) values between APURE and subsp. ATCC 29999, APURE and subsp. MEX47-22, and APURE and JAR are 61.6, 61.2 and 64.1 %, respectively. These values are below the 70 % divergence threshold that delimits prokaryotic species. dDDH scores between JAR and subsp. ATCC 29999 and between JAR and subsp. MEX47-22 are 71.9 and 74.8 %, respectively. These values are within the 70 and 79 % divergence thresholds that delimit prokaryotic subspecies. Based on these genomic divergence values, APURE and JAR represent two different taxa, for which we propose the names: sp. nov. with APURE (=CCM 9236 =CCOS 2019) as type strain and subsp. subsp. nov. with JAR (=CCM 9235 =CCOS 2021) as type strain. Our study contributes to a better understanding of the biodiversity of an important bacterial group with enormous biotechnological and agricultural potential.
Topics: Animals; Photorhabdus; Phylogeny; RNA, Ribosomal, 16S; Proteome; Bacterial Typing Techniques; Sequence Analysis, DNA; DNA, Bacterial; Base Composition; Fatty Acids; Nematoda
PubMed: 37171451
DOI: 10.1099/ijsem.0.005872 -
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 -
Nature Oct 2022Entomopathogenic nematodes are widely used as biopesticides. Their insecticidal activity depends on symbiotic bacteria such as Photorhabdus luminescens, which produces...
Entomopathogenic nematodes are widely used as biopesticides. Their insecticidal activity depends on symbiotic bacteria such as Photorhabdus luminescens, which produces toxin complex (Tc) toxins as major virulence factors. No protein receptors are known for any Tc toxins, which limits our understanding of their specificity and pathogenesis. Here we use genome-wide CRISPR-Cas9-mediated knockout screening in Drosophila melanogaster S2R+ cells and identify Visgun (Vsg) as a receptor for an archetypal P. luminescens Tc toxin (pTc). The toxin recognizes the extracellular O-glycosylated mucin-like domain of Vsg that contains high-density repeats of proline, threonine and serine (HD-PTS). Vsg orthologues in mosquitoes and beetles contain HD-PTS and can function as pTc receptors, whereas orthologues without HD-PTS, such as moth and human versions, are not pTc receptors. Vsg is expressed in immune cells, including haemocytes and fat body cells. Haemocytes from Vsg knockout Drosophila are resistant to pTc and maintain phagocytosis in the presence of pTc, and their sensitivity to pTc is restored through the transgenic expression of mosquito Vsg. Last, Vsg knockout Drosophila show reduced bacterial loads and lethality from P. luminescens infection. Our findings identify a proteinaceous Tc toxin receptor, reveal how Tc toxins contribute to P. luminescens pathogenesis, and establish a genome-wide CRISPR screening approach for investigating insecticidal toxins and pathogens.
Topics: Animals; Bacterial Toxins; Biological Control Agents; CRISPR-Cas Systems; Culicidae; Drosophila Proteins; Drosophila melanogaster; Fat Body; Gene Editing; Gene Knockdown Techniques; Hemocytes; Humans; Moths; Mucins; Pest Control, Biological; Phagocytosis; Photorhabdus; Repetitive Sequences, Amino Acid; Transgenes; Virulence Factors
PubMed: 36171290
DOI: 10.1038/s41586-022-05250-7 -
Insects Aug 2020This special issue contains articles that add to the ever-expanding toolbox of insect pathogenic nematodes (entomopathogenic nematodes; EPNs) as well articles that...
This special issue contains articles that add to the ever-expanding toolbox of insect pathogenic nematodes (entomopathogenic nematodes; EPNs) as well articles that provide new insights into the mutualistic interaction between EPNs and their hosts. The study of natural infection models such as EPNs allows detailed insight into micro- and macro-evolutionary dynamics of innate immune reactions, including known but also emerging branches of innate immunity. Additional new insights into the kinetics of EPN infections are gained by increased spatiotemporal resolution of advanced transcriptome studies and live imaging.
PubMed: 32872298
DOI: 10.3390/insects11090577 -
Insects Apr 2015The scientific community working in the field of insect pathology is experiencing an increasing academic and industrial interest in the discovery and development of new... (Review)
Review
The scientific community working in the field of insect pathology is experiencing an increasing academic and industrial interest in the discovery and development of new bioinsecticides as environmentally friendly pest control tools to be integrated, in combination or rotation, with chemicals in pest management programs. In this scientific context, market data report a significant growth of the biopesticide segment. Acquisition of new technologies by multinational Ag-tech companies is the center of the present industrial environment. This trend is in line with the requirements of new regulations on Integrated Pest Management. After a few decades of research on microbial pest management dominated by Bacillus thuringiensis (Bt), novel bacterial species with innovative modes of action are being discovered and developed into new products. Significant cases include the entomopathogenic nematode symbionts Photorhabdus spp. and Xenorhabdus spp., Serratia species, Yersinia entomophaga, Pseudomonas entomophila, and the recently discovered Betaproteobacteria species Burkholderia spp. and Chromobacterium spp. Lastly, Actinobacteria species like Streptomyces spp. and Saccharopolyspora spp. have gained high commercial interest for the production of a variety of metabolites acting as potent insecticides. With the aim to give a timely picture of the cutting-edge advancements in this renewed research field, different representative cases are reported and discussed.
PubMed: 26463190
DOI: 10.3390/insects6020352 -
Trends in Parasitology Jan 2020Xenorhabdus and Photorhabdus species are symbiotic bacteria of the insect-pathogenic soil nematodes that produce insecticidal compounds lethal to prey insects. Recently,... (Review)
Review
Xenorhabdus and Photorhabdus species are symbiotic bacteria of the insect-pathogenic soil nematodes that produce insecticidal compounds lethal to prey insects. Recently, there has been much interest in adapting these insecticidals for mosquito control. Here, I advocate the potential of Xenorhabdus/Photorhabdus as natural sources of mosquitocides (larvicides, adulticides) and feeding-deterrents.
Topics: Animals; Culicidae; Insecticides; Mosquito Control; Nematoda; Photorhabdus; Symbiosis; Xenorhabdus
PubMed: 31375436
DOI: 10.1016/j.pt.2019.07.003