Characterization of a Heme-Regulated Non-Coding RNA Encoded by the prrF Locus of Pseudomonas aeruginosa

Pseudomonas aeruginosa, an opportunistic pathogen, requires iron for virulence and can obtain this nutrient via the acquisition of heme, an abundant source of iron in the human body. A surplus of either iron or heme can lead to oxidative stress; thus, the Fur (ferric uptake regulator) protein blocks expression of genes required for iron and heme uptake in iron-replete environments. Fur also represses expression of two nearly identical genes encoding the 116- and 114-nucleotide (nt) long PrrF1 and PrrF2 RNAs, respectively. While other Pseudomonads encode for the two PrrF RNAs at separate genomic loci, PrrF1 and PrrF2 are encoded in tandem in all sequenced strains of P. aeruginosa. In this report we characterize a third longer transcript encoded by the prrF locus, PrrH, which is repressed by heme as well as iron. We mapped the PrrH RNA in PA01 using 5′ rapid amplification of cDNA ends (RACE) and northern analysis, demonstrating the PrrH RNA is 325 nt in length. Accordingly, transcription of PrrH initiates at the 5′ end of prrF1, proceeds through the prrF1 terminator and prrF1-prrF2 intergenic sequence (95 nt), and terminates at the 3′ end of the prrF2 gene. We also present evidence that repression of PrrH by heme causes increased expression of previously identified PrrF-regulated genes, as well as newly identified iron- and heme-activated genes. Thus, the PrrH RNA appears to impart a novel heme regulatory mechanism to P. aeruginosa

Dual-Seq Transcriptomics Reveals The Battle For Iron During Pseudomonas Aeruginosa Acute Murine Pneumonia

Determining bacterial gene expression during infection is fundamental to understand pathogenesis. In this study, we used dual RNA-seq to simultaneously measure P. aeruginosa and the murine host’s gene expression and response to respiratory infection. Bacterial genes encoding products involved in metabolism and virulence were differentially expressed during infection and the type III and VI secretion systems were highly expressed in vivo. Strikingly, heme acquisition, ferric-enterobactin transport, and pyoverdine biosynthesis genes were found to be significantly up-regulated during infection. In the mouse, we profiled the acute immune response to P. aeruginosa and identified the pro-inflammatory cytokines involved in acute response to the bacterium in the lung. Additionally, we also identified numerous host iron sequestration systems upregulated during infection. Overall, this work sheds light on how P. aeruginosa triggers a pro-inflammatory response and competes for iron with the host during infection, as iron is one of the central elements for which both pathogen and host fight during acute pneumonia

What benefits do community forests provide, and to whom? A rapid assessment of ecosystem services from a Himalayan forest, Nepal

In Nepal, community forestry is part of a national strategy for livelihoods improvement and environmental protection. However, analysis of the social, economic and environmental impacts of community forestry is often limited, restricted to a narrow set of benefits (e.g. non-timber forest products) and rarely makes comparisons with alternative land-use options (e.g. agriculture). This study, conducted at Phulchoki Mountain Forest Important Bird and Biodiversity Area (IBA) in the Kathmandu Valley, used methods from the Toolkit for Ecosystem Service Site-based Assessment (TESSA) to compare multiple ecosystem service values (including carbon storage, greenhouse gas sequestration, water provision, water quality, harvested wild goods, cultivated goods and nature-based recreation) provided by the site in its current state and a plausible alternative state in which community forestry had not been implemented. We found that outcomes from community forestry have been favourable for most stakeholders, at most scales, for most services and for important biodiversity at the site. However, not all ecosystem services can be maximised simultaneously, and impacts of land-use decisions on service beneficiaries appear to differ according to socio-economic factors. The policy implications of our findings are discussed in the context of proposals to designate Phulchoki Mountain Forest IBA as part of a Conservation Area

Cystic Fibrosis isolates of Pseudomonas aeruginosa retain iron-regulated antimicrobial activity against Staphylococcus aureus through the action of multiple alkylquinolones

Cystic fibrosis (CF) is a hereditary disease that predisposes individuals to pulmonary dysfunction and chronic infections. Early infection of the CF lung with Staphylococcus aureus is common, while Pseudomonas aeruginosa becomes dominant as disease progresses. Emergence of P. aeruginosa likely depends on the action of multiple 2-alkyl-4-(1H)-quinolones (AQ) secreted by this organism. We recently showed that antimicrobial activity against S. aureus is enhanced by iron depletion and is dependent upon multiple AQ metabolites. Two of these AQs, the Pseudomonas quinolone signal [PQS; 2-heptyl-3-hydroxy-4(1H)-quinolone] and 2-heptyl-4-hydroxyquinoline (HHQ), are quorum sensing molecules that activate the expression of multiple microbicidal factors. Here we show for the first time that HHQ also exhibits innate antimicrobial activity against S. aureus. We further show that iron depletion potentiates the antistaphylococcal activity of HHQ, as well as 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO), another AQ that functions as a cytochrome B inhibitor. Notably, we found that deletion of the genes for the terminal biosynthetic steps for either PQS or HQNO results in overproduction of the HHQ intermediate, likely maintaining the ability of these mutants to mediate antimicrobial activity. Compensatory increases in HHQ were also observed in PQS-deficient CF isolates, which also retained the ability to mediate iron-regulated antimicrobial activity against S. aureus. These studies demonstrate that iron-regulated antimicrobial activity of P. aeruginosa against S. aureus is due to the cumulative effects of multiple AQ metabolites, both the production and activity of which are modulated by environmental iron levels

How coastal strategic planning reflects interrelationships between ecosystem services: a four-step method

Explicit and integrated inclusion of ecosystem services (ESs) and their interrelationships can improve the quality of strategic plans and decision-making processes. However, there is little systematic analysis of how ES interrelationships are framed in policy language, particularly in coastal planning discourse. The objective of this paper is therefore to present a four-step method, based on content analysis, to assess ES interrelationships in coastal strategic planning documents. The method consists of: 1) selecting strategic plans; 2) identifying ESs; 3) identifying drivers, ESs and their effects; and 4) constructing relational diagrams. The four-step method is applied to a case of Jiaozhou Bay in China, demonstrating its capacity of identifying which drivers and ES trade-offs and synergies are formulated in coastal strategic plans. The method is helpful to identify overlooked ES interrelationships, inform temporal and spatial issues, and assess the continuity of plans' attention to interrelationships. The main methodological contributions are discussed by emphasizing its broad scope of drivers and ESs and an explicit distinction among the cause of relationships. The developed method also has the potential of cross-fertilizing other kinds of approaches and facilitating practical planning processes

Mapping the stray domestic cat (Felis catus) population in New Zealand: Species distribution modelling with a climate change scenario and implications for protected areas

Species distribution models of stray cats were developed using two types of occurrence data: (i) a combined dataset of stray cats and cat colonies in Auckland and projected to the wider New Zealand area; and (ii) population density as an analogue for country-wide stray cat occurrence. These occurrence data, together with sets of environmental variables were used as input to the Maxent modelling tool to produce maps of suitability for the species. Environmental variables used in the models consist of current bioclimatic conditions, and a future climate scenario (RCP8.5 for year 2070 CCSM model). Commonly occurring bias in the modelling process due to latitude, the area for selecting background points in model evaluation, inherent spatial autocorrelation of occurrence points, and correlated bioclimatic variables were explicitly addressed. Results show that the North Island consistently provide more suitable areas for stray cats with increased suitability in a high emission climate change condition. Key protected areas at risk from the increased suitability to stray cats are also presented

Ecosystem services and the idea of shared values

Ecosystem services conceptualise the diverse values that ecosystems provide to humanity. This was recognised in the United Kingdom's National Ecosystem Assessment, which noted that appreciation of the full value of ecosystem services requires recognition of values that are shared. By operationalising the shared values concept, it is argued that the contribution of ecosystem services to human well-being can be represented more holistically. This paper considers current understanding of shared values and develops a new metanarrative of shared values beyond the aggregated utilities of individuals. This metanarrative seeks to conceptualise how values can be held both individually and communally, and what this means for identifying their scale and means of enumeration. The paper poses a new reading of the idea of shared values that reconciles the elicitation of preformed individual values with the formation and expression of shared social values. The implication is that shared values need to be conceived as normative constructs that are derived through social processes of value formation and expression. Shared values thus do not necessarily exist a priori; they can be deliberated through formal and informal processes through which individuals can separate their own preferences from a broader metanarrative about what values ought to be shared

Customising virtual globe tours to enhance community awareness of local landscape benefits

Our wellbeing depends upon the services provided by ecosystems and their components. Despite recent advances in academic understanding of ecosystem services, and consideration in UK national environmental policy, a greater awareness is needed at community and individual levels. Dynamic features of virtual globe applications have considerable potential for helping convey the multi-dimensional context of ecosystem services and promoting general awareness. In a case study targeting residents in a small urban fringe river catchment in Norfolk, UK, representatives from local authorities and responsible agencies collaborated with scientists to produce extensive customisation of virtual globes in this context. By implementing a virtual flight over the catchment, different views and scales are traversed to set the context for landscape features and ecosystem services. Characteristic sites, e.g. supplying cultural services, are displayed and relationships with the natural environment are explained using linked on-screen text. Implementation is cost-effective and described for practitioners in ecosystem and landscape management, who may be inexperienced in landscape visualisation. Supplied as three pre-packaged virtual tours, products are made available for download and are publicised at a variety of engagement events, including teaching events with schoolchildren. The tours have attracted public interest and generated positive feedback about improving knowledge of local natural assets. Schoolchildren show confidence with the interface, but supplementary problem-based activities can improve learning opportunities. The capacity of virtual globes to support more participatory involvement of the public in local ecosystem management may increase in the future, but such visualisations can already help promote community awareness of local landscape benefits