Symbiont-mediated RNA interference in insects

RNA interference (RNAi) methods for insects are often limited by problems with double-stranded (ds) RNA delivery, which restricts reverse genetics studies and the development of RNAi-based biocides. We therefore delegated to insect symbiotic bacteria the task of: (i) constitutive dsRNA synthesis and (ii) trauma-free delivery. RNaseIII-deficient, dsRNA-expressing bacterial strains were created from the symbionts of two very diverse pest species: a long-lived blood-sucking bug, Rhodnius prolixus, and a short-lived globally invasive polyphagous agricultural pest, western flower thrips (Frankliniella occidentalis). When ingested, the manipulated bacteria colonized the insects, successfully competed with the wild-type microflora, and sustainably mediated systemic knockdown phenotypes that were horizontally transmissible. This represents a significant advance in the ability to deliver RNAi, potentially to a large range of non-model insects

Draft Genomes, Phylogenetic Reconstruction, and Comparative Genomics of Two Novel Cohabiting Bacterial Symbionts Isolated from Frankliniella occidentalis

Obligate bacterial symbionts are widespread in many invertebrates, where they are often confined to specialized host cells and are transmitted directly from mother to progeny. Increasing numbers of these bacteria are being characterized but questions remain about their population structure and evolution. Here we take a comparative genomics approach to investigate two prominent bacterial symbionts (BFo1 and BFo2) isolated from geographically separated populations of western flower thrips, Frankliniella occidentalis. Our multifaceted approach to classifying these symbionts includes concatenated multilocus sequence analysis (MLSA) phylogenies, ribosomal multilocus sequence typing (rMLST), construction of whole-genome phylogenies, and in-depth genomic comparisons. We showed that the BFo1 genome clusters more closely to species in the genus Erwinia, and is a putative close relative to Erwinia aphidicola. BFo1 is also likely to have shared a common ancestor with Erwinia pyrifoliae/Erwinia amylovora and the nonpathogenic Erwinia tasmaniensis and genetic traits similar to Erwinia billingiae. The BFo1 genome contained virulence factors found in the genus Erwinia but represented a divergent lineage. In contrast, we showed that BFo2 belongs within the Enterobacteriales but does not group closely with any currently known bacterial species. Concatenated MLSA phylogenies indicate that it may have shared a common ancestor to the Erwinia and Pantoea genera, and based on the clustering of rMLST genes, it was most closely related to Pantoea ananatis but represented a divergent lineage. We reconstructed a core genome of a putative common ancestor of Erwinia and Pantoea and compared this with the genomes of BFo bacteria. BFo2 possessed none of the virulence determinants that were omnipresent in the Erwinia and Pantoea genera. Taken together, these data are consistent with BFo2 representing a highly novel species that maybe related to known Pantoea

Streptomyces isolates from the soil of an ancient irish cure site, capable of inhibiting multi-resistant bacteria and yeasts

Traditional Irish medicines are often intertwined with ritual and spirituality, making it difficult to substantiate the validity of their claims. In this manuscript, we use molecular and microscopic techniques to investigate some microorganisms that might be responsible for the reputed healing properties of an ancient Irish soil cure known as the Blessed clay from a site in Boho in the West Fermanagh Scarplands. We previously reported the isolation of an antibiotic producing bacteria from this soil. In this report, we characterize the antibiotic activity of a further six isolates of Streptomyces from this source. Two of these isolates inhibit the growth of multi-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, two inhibit the growth of the yeast Starmerella bombicola, and two have as yet undetermined activity. Genetic analysis of these Streptomyces reveals the potential to synthesize varieties of antibiotics similar to cypemycin, griseochelin, macrolactams, and candicidin. From these observations, we suggest that part of the medicinal reputation of the Blessed clay may lie in the diversity of antimicrobial producing Streptomyces isolated from this soil. These findings highlight the potential for antibiotic discovery in this area

The isolation of a novel streptomyces sp. CJ13 from a traditional irish folk medicine alkaline grassland soil that inhibits multiresistant pathogens and yeasts

The World Health Organization recently stated that new sources of antibiotics are urgently required to stem the global spread of antibiotic resistance, especially in multiresistant Gram-negative bacteria. Although it was thought that many of the original sources of antibiotics were exhausted, innovative research has revealed promising new sources of antibiotic discovery in traditional medicine associated with Streptomyces. In this work we investigated the potential of a specific limestone grassland soil, associated with Irish folk medicine, as a new source of antimicrobial discovery. Using selective enrichment and isolation techniques on a limestone grassland soil sample obtained from Boho, West Fermanagh, we isolated Streptomyces sp. CJ13. This bacterium inhibited the growth of a broad range of pathogens in vitro including Gram positive Staphylococcus aureus (MRSA 43300) and Gram negative multiresistant Pseudomonas aeruginosa (PA01), as well as the anaerobic bacteria Propionibacterium acnes and the yeast Starmerella bombicola. Genome sequencing and phylogenetic analysis revealed Streptomyces sp. CJ13 to be closely related to an unclassified Streptomyces sp. MJM1172, Streptomyces sp. Mg1 and two species known as Streptomyces sp. ICC1 and ICC4 from a karst region in British Columbia. The closest type species to Streptomyces sp. CJ13 was Streptomyces lavendulae subspecies lavendulae. Analysis of Streptomyces sp. CJ13 whole genome sequence using the secondary metabolite prediction tool antiSMASH revealed similarities to several antibiotic gene synthesis clusters including salinichelin, mediomycin A, weishanmycin, combamide, heat stable antifungal factor and SAL-2242. These results demonstrate the potential of this alkaline grassland soil as a new resource for the discovery of a broad range of antimicrobial compounds including those effective against multiresistant Gram negative bacteria

The Impact of Probiotic Supplementation on the Development of the Infant Gut Microbiota: An Exploratory Follow-Up of a Randomised Controlled Trial

Early-life establishment of the gut microbiota plays a role in lifelong health, with disruptions linked to heightened risks of metabolic and immune disorders. Probiotic supplementation may be used to modulate the infant gut microbiome to promote favourable development. Here, we evaluate how Lab4B probiotic supplementation shapes the development of the infant gut microbiome over the first 6 months. Faecal samples collected from infants enrolled in PROBAT (ISRCTN26287422), a randomised, double-blind, placebo-controlled trial, were analysed using culture-dependent and -independent (16S rDNA and metagenomic shotgun sequencing) techniques to examine the composition, diversity, and metabolic capabilities of the microbiome, as well as the abundance of antimicrobial resistance genes (ARGs). Probiotic supplementation encouraged the development of a microbiome with a distinct composition characterised by elevated abundances of Bifidobacteriaceae in the first 6 weeks (p = 0.006) and Lactobacillaceae throughout the first 6 months (p < 0.05 at every 6-week time point), accelerated microbial diversification, reduced abundance of beta-lactam- and cephalosporin-resistance genes, and differences in predicted metabolic capabilities at the start and end points. Supplementation of this neonatal population, which is at high risk of atopy, with the Lab4B probiotic significantly influenced the development of the infant gut microbiota during the first 6 months

The dpsA Gene of Streptomyces coelicolor: Induction of Expression from a Single Promoter in Response to Environmental Stress or during Development

The DpsA protein plays a dual role in Streptomyces coelicolor, both as part of the stress response and contributing to nucleoid condensation during sporulation. Promoter mapping experiments indicated that dpsA is transcribed from a single, sigB-like dependent promoter. Expression studies implicate SigH and SigB as the sigma factors responsible for dpsA expression while the contribution of other SigB-like factors is indirect by means of controlling sigH expression. The promoter is massively induced in response to osmotic stress, in part due to its sensitivity to changes in DNA supercoiling. In addition, we determined that WhiB is required for dpsA expression, particularly during development. Gel retardation experiments revealed direct interaction between apoWhiB and the dpsA promoter region, providing the first evidence for a direct WhiB target in S. coelicolor

Nicotinamide N-Methyltransferase: An Emerging Protagonist in Cancer Macro(r)evolution

Nicotinamide N-methyltransferase (NNMT) has progressed from being considered merely a Phase II metabolic enzyme to one with a central role in cell function and energy metabolism. Over the last three decades, a significant body of evidence has accumulated which clearly demonstrates a central role for NNMT in cancer survival, metastasis, and drug resistance. In this review, we discuss the evidence supporting a role for NNMT in the progression of the cancer phenotype and how it achieves this by driving the activity of pro-oncogenic NAD+-consuming enzymes. We also describe how increased NNMT activity supports the Warburg effect and how it promotes oncogenic changes in gene expression. We discuss the regulation of NNMT activity in cancer cells by both post-translational modification of the enzyme and transcription factor binding to the NNMT gene, and describe for the first time three long non-coding RNAs which may play a role in the regulation of NNMT transcription. We complete the review by discussing the development of novel anti-cancer therapeutics which target NNMT and provide insight into how NNMT-based therapies may be best employed clinically.</jats:p

Nicotinamide N-Methyltransferase: An Emerging Protagonist in Cancer Macro(r)evolution

Nicotinamide N-methyltransferase (NNMT) has progressed from being considered merely a Phase II metabolic enzyme to one with a central role in cell function and energy metabolism. Over the last three decades, a significant body of evidence has accumulated which clearly demonstrates a central role for NNMT in cancer survival, metastasis, and drug resistance. In this review, we discuss the evidence supporting a role for NNMT in the progression of the cancer phenotype and how it achieves this by driving the activity of pro-oncogenic NAD+-consuming enzymes. We also describe how increased NNMT activity supports the Warburg effect and how it promotes oncogenic changes in gene expression. We discuss the regulation of NNMT activity in cancer cells by both post-translational modification of the enzyme and transcription factor binding to the NNMT gene, and describe for the first time three long non-coding RNAs which may play a role in the regulation of NNMT transcription. We complete the review by discussing the development of novel anti-cancer therapeutics which target NNMT and provide insight into how NNMT-based therapies may be best employed clinically