Genomic Characterisation of Mushroom Pathogenic Pseudomonads and Their Interaction with Bacteriophages.

Bacterial diseases of the edible white button mushroom caused by species cause a reduction in crop yield, resulting in considerable economic loss. We examined bacterial pathogens of mushrooms and bacteriophages that target them to understand the disease and opportunities for control. The genome encoded a single type III protein secretion system (T3SS), but contained the largest number of non-ribosomal peptide synthase (NRPS) genes, multimodular enzymes that can play a role in pathogenicity, including a putative tolaasin-producing gene cluster, a toxin causing blotch disease symptom.

Temperature Restriction in Entomopathogenic Bacteria.

Temperature plays an important role in bacteria-host interactions and can be a determining factor for host switching. In this study we sought to investigate the reasons behind growth temperature restriction in the entomopathogenic enterobacterium . has a complex dual symbiotic and pathogenic life cycle.

Description and initial characterization of metatranscriptomic nidovirus-like genomes from the proposed new family Abyssoviridae, and from a sister group to the Coronavirinae, the proposed genus Alphaletovirus.

Transcriptomics has the potential to discover new RNA virus genomes by sequencing total intracellular RNA pools. In this study, we have searched publicly available transcriptomes for sequences similar to viruses of the Nidovirales order. We report two potential nidovirus genomes, a highly divergent 35.

Policing the legume-Rhizobium symbiosis: a critical test of partner choice.

In legume-Rhizobium symbioses, specialised soil bacteria fix atmospheric nitrogen in return for carbon. However, ineffective strains can arise, making discrimination essential. Discrimination can occur via partner choice, where legumes prevent ineffective strains from entering, or via sanctioning, where plants provide fewer resources.

Transcript Abundance of Photorhabdus Insect-Related (Pir) Toxin in Manduca sexta and Galleria mellonella Infections.

In this study, we assessed pirAB toxin transcription in (strain TT01) (Enterobacteriaceae) by comparing mRNA abundance under in vivo and in vitro conditions. In vivo assays considered both natural and forced infections with two lepidopteran hosts: and . Three portals of entry were utilized for the forced infection assays: (a) integument; (b) the digestive route (via mouth and anus); and (c) the tracheal route (via spiracles).

From Insect to Man: Photorhabdus Sheds Light on the Emergence of Human Pathogenicity.

Photorhabdus are highly effective insect pathogenic bacteria that exist in a mutualistic relationship with Heterorhabditid nematodes. Unlike other members of the genus, Photorhabdus asymbiotica can also infect humans. Most Photorhabdus cannot replicate above 34°C, limiting their host-range to poikilothermic invertebrates.

Evolutionary rewiring of bacterial regulatory networks.

Bacteria have evolved complex regulatory networks that enable integration of multiple intracellular and extracellular signals to coordinate responses to environmental changes. However, our knowledge of how regulatory systems function and evolve is still relatively limited. There is often extensive homology between components of different networks, due to past cycles of gene duplication, divergence, and horizontal gene transfer, raising the possibility of cross-talk or redundancy.

Evolution. Evolutionary resurrection of flagellar motility via rewiring of the nitrogen regulation system.

A central process in evolution is the recruitment of genes to regulatory networks. We engineered immotile strains of the bacterium Pseudomonas fluorescens that lack flagella due to deletion of the regulatory gene fleQ. Under strong selection for motility, these bacteria consistently regained flagella within 96 hours via a two-step evolutionary pathway.

Insect-specific production of new GameXPeptides in photorhabdus luminescens TTO1, widespread natural products in entomopathogenic bacteria.

Discovery of new natural products by heterologous expression reaches its limits, especially when specific building blocks are missing in the heterologous host or the production medium. Here, we describe the insect-specific production of the new GameXPeptides E-H (5-8) from Photorhabdus luminescens TTO1, which can be produced heterologously from expression of the GameXPeptide synthetase GxpS only upon supplementation of the production media with the missing building blocks, and thus must be regarded as the true natural products under natural conditions.

Inactivation of the antibacterial and cytotoxic properties of silver ions by biologically relevant compounds.

There has been a recent surge in the use of silver as an antimicrobial agent in a wide range of domestic and clinical products, intended to prevent or treat bacterial infections and reduce bacterial colonization of surfaces. It has been reported that the antibacterial and cytotoxic properties of silver are affected by the assay conditions, particularly the type of growth media used in vitro. The toxicity of Ag+ to bacterial cells is comparable to that of human cells.

Pyruvate is synthesized by two pathways in pea bacteroids with different efficiencies for nitrogen fixation.

Nitrogen fixation in legume bacteroids is energized by the metabolism of dicarboxylic acids, which requires their oxidation to both oxaloacetate and pyruvate. In alfalfa bacteroids, production of pyruvate requires NAD+ malic enzyme (Dme) but not NADP+ malic enzyme (Tme). However, we show that Rhizobium leguminosarum has two pathways for pyruvate formation from dicarboxylates catalyzed by Dme and by the combined activities of phosphoenolpyruvate (PEP) carboxykinase (PckA) and pyruvate kinase (PykA).

A thin film detection/response system for pathogenic bacteria.

This paper describes the modification of nonwoven fabric such that it responds by releasing an encapsulated antimicrobial from within an attached vesicle in response to two species of pathogenic bacteria (Staphylococcus aureus MSSA 476 and Pseudomonas aeruginosa PAO1), but does not respond to nonpathogenic Escherichia coli DH5alpha. This concept is based on the generalization that a majority of pathogenic bacteria secrete virulence factors such as toxins and lipases that actively damage cell membranes, typically observed as tissue damage around infected wounds, while nonpathogenic bacteria do not (or not at high concentration). The eventual aim of this work is to produce responsive dressings which release antimicrobials and change color only on infected wounds.