Development of a UK core dataset for geriatric medicine research: : a position statement and results from a Delphi consensus process

Funding AS and MW are funded by the Newcastle National Institute for Health (NIHR) Biomedical Research Centre, which also funded the initial meeting of academic clinicians in geriatric medicine during the Delphi process. The views expressed in this article are those of the authors and not necessarily those of the NIHR, the NHS, or the Department of Health. Acknowledgements The authors acknowledge the contributions of members of the UK Geriatric Medicine Core Dataset Extended Working Group.Peer reviewedPublisher PD

Horizontal plasmid transfer and community dynamics involved in 2,4-dichlorophenoxyacetic acid (2,4-D) degradation

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Significance of microbial interactions in the mycorrhizosphere

There are several major types of mycorrhiza that are classified according to morphology and the types of fungi involved. The dominant type of mycorrhiza in terms of plant species and distribution are the Arbuscular mycorrhizas (AM) that form between fungi from the Glomeromycota and angiosperms, gymnosperms, pteridophytes, and bryophytes. Based on taxonomy, approximately 160 species of AM fungus have been described, although this is likely to be a considerable underestimate of actual diversity. In AM associations, the fungus penetrates root cortical cells in which it proliferates and forms arbuscules through which materials are exchanged between the symbionts. In addition, the biological and chemical interactions that take place within the mycorrhizosphere are still largely unexplored, and furthermore the relative importance of the host and mycorrhizal fungus mycelium for directing interactions largely remains to be resolved. This information should provide new possibilities to exploit biological interactions within the mycorrhizosphere for agricultural and environmental management

Mycorrhization helper bacteria: a case of specificity for altering ectomycorrhiza architecture but not ectomycorrhiza formation

International audienceMycorrhization helper bacteria (MHB), isolated from phylogenetically distinct ectomycorrhizal symbioses involving Lactarius rufus, Laccaria bicolor or Suillus luteus, were tested for fungus specificity to enhance L. rufus–Pinus sylvestris or L. bicolor–P. sylvestris mycorrhiza formation. As MHB isolated from the L. rufus and S. luteus mycorrhiza were originally characterised using a microcosm system, we assessed their ability to enhance mycorrhiza formation in a glasshouse system in order to determine the extent to which MHB are system-specific. Paenibacillus sp. EJP73, an MHB for L. rufus in the microcosm, significantly enhanced L. bicolor mycorrhiza formation in the glasshouse, demonstrating that the MHB effect of this bacterium is neither fungus-specific nor limited to the original experimental system. Although the five MHB strains studied were unable to significantly enhance L. rufus mycorrhiza formation, two of them did have a significant effect on dichotomous short root branching by L. rufus. The effect was specific to Paenibacillus sp. EJP73 and Burkholderia sp. EJP67, the two strains isolated from L. rufus mycorrhiza, and was not associated with auxin production. Altered mycorrhiza architecture rather than absolute number of mycorrhizal roots may be an important previously overlooked parameter for defining MHB effects

Importance of mycorrhization helper bacteria cell density and metabolite localization for the Pinus sylvestris Lactarius rufus symbiosis

Mycorrhization helper bacteria, Paenibacillus sp. EJP73 and Burkholderia sp. EJP67, were used to study the importance of bacterial inoculum dose and bacterial derived soluble and volatile metabolites localization for enhancing mycorrhiza formation in the Pinus sylvestris-Lactarius rufus symbiosis, using a laboratory based microcosm. EJP73 and EJP67 produced different responses in relation to the inoculum dose; EJP73 significantly enhanced mycorrhiza formation to the same degree at all doses tested (10(5), 10(7), 10(9) and 10(10) CFU mL(-1)), whereas, EJP67 only stimulated mycorrhiza formation within a narrow range of inoculum densities (10(7) and 10(9) CFU mL(-1)). The importance of soluble bacterial metabolites was assessed by applying spent broth derived from exponential and stationary phase bacterial cultures to microcosms. No spent broth enhanced mycorrhiza formation over the control. As EJP73 produced the helper effect over a wide range of inoculum doses, this bacterium was chosen for further study. Physical separation of EJP73 from the fungal and plant symbiosis partners was carried out, in order to determine the contribution of constitutively produced bacterial volatile metabolites to the mycorrhization helper bacteria effect. When EJP73 was physically separated from the symbiosis, it had a significant negative effect on mycorrhiza formation. These results suggest that close proximity, or indeed cell contact, is required for the helper effect. Therefore, fluorescent in situ hybridization in conjunction with cryosectioning was used to determine the localization of EJP73 in mycorrhizal tissue. The cells were found to occur as rows or clusters (similar to 10 cells) within the mycorrhizal mantle, both at the root tip and along the length of the mycorrhizal short roots