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The already enormous burden caused by tuberculosis (TB) will be further aggravated by the association of this disease with modern epidemics, as human immunodeficiency virus and diabetes. Furthermore, the increasingly aging population and the wider use of suppressive immune therapies hold the potential to enhance the incidence of TB. New preventive and therapeutic strategies based on recent advances on our understanding of TB are thus needed. In particular, understanding the intricate network of events modulating inflammation in TB will help to build more effective vaccines and host-directed therapies to stop TB. This review integrates the impact of host, pathogen, and extrinsic factors on inflammation and the almost scientifically unexplored complexity emerging from the interactions between these three factors. We highlight the exciting data showing a contribution of this troika for the clinical outcome of TB and the need of incorporating it when developing novel strategies to rewire the immune response in TB. ; HN-B acknowledges the receipt of research scholarships from Bolsa D. Manuel de Mello and the Portuguese Society for Pneumology. NO acknowledges FCT IF/00474/2014. SG is funded by the European Research Council (grant number 309540-EVODRTB); the Swiss National Science Foundation (grant number 310030_166687) SystemsX.ch. IC lab is financed by Ministerio de Economía y Competitividad (Spanish Government) research grant SAF2013-43521-R, SAF2016-77346-R, and PROMETEO/2016/122 from Generalitat Valenciana and the European Research Council (ERC) (638553-TB-ACCELERATE). The MS lab is financed by FEDER—Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020—Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through FCT in the framework of the project "Institute for Research and Innovation in Health Sciences" (POCI-01-0145-FEDER-007274). MS is an FCT Principal Investigator. Some graphical elements in the figures were designed by kjpargeter/Freepik. The funding agencies had no role in the design of the manuscript. ; Peer reviewed

9 páginas, 2 tablas, 2 figuras ; Plants host taxonomically and functionally complex communities of microbes. However, ecological studies on plant-microbe interactions rarely address the role of multiple co-occurring plant-associated microbes. Here, we contend that plant-associated microbes interact with each other and can have joint consequences for higher trophic levels. In this study we recorded the occurrence of the plant seed pathogenic fungus Claviceps purpurea and aphids (Sitobion sp.) on an established field experiment with red fescue (Festuca rubra) plants symbiotic to a seed transmitted endophytic fungus Epichloë festucae (E+) or non-symbiotic (E-). Both fungi are known to produce animal-toxic alkaloids. The study was conducted in a semi-natural setting, where E+ and E- plants from different origins (Spain and Northern Finland) were planted in a randomized design in a fenced common garden at Kevo Subarctic Research Station in Northern Finland. The results reveal that 45% of E+ plants were infected with Claviceps compared to 31% of E- plants. Uninfected plants had 4.5 times more aphids than Claviceps infected plants. By contrast, aphid infestation was unaffected by Epichloë symbiosis. Claviceps alkaloid concentrations correlated with a decrease in aphid numbers, which indicates their insect deterring features. These results show that plant mutualistic fungi can increase the infection probability of a pathogenic fungus, which then becomes beneficial to the plant by controlling herbivorous insects. Our study highlights the complexity and context dependency of species-species and multi-trophic interactions, thus challenging the labeling of species as plant mutualists or pathogens. ; This work was supported by the Academy of Finland (KS, Grant Nos. 295976 and 326226; MH, Grant No. 311077; BF, Grant No. 324523), the Spanish Ministry of Science and Innovation and FEDER grant PID2019-109133RB-I00, and from the project CLU-2019-05—IRNASA/CSIC Unit of Excellence funded by Junta de Castilla y León and cofinanced by the European Union (ERDF Europe drives our growth). ; Peer reviewed

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hinzke, T., Kleiner, M., Breusing, C., Felbeck, H., Häsler, R., Sievert, S. M., Schlüter, R., Rosenstiel, P., Reusch, T. B. H., Schweder, T., & Markert, S. Host-microbe interactions in the chemosynthetic Riftia pachyptila symbiosis. Mbio, 10(6), (2019): e02243-19, doi:10.1128/mBio.02243-19. ; The deep-sea tubeworm Riftia pachyptila lacks a digestive system but completely relies on bacterial endosymbionts for nutrition. Although the symbiont has been studied in detail on the molecular level, such analyses were unavailable for the animal host, because sequence information was lacking. To identify host-symbiont interaction mechanisms, we therefore sequenced the Riftia transcriptome, which served as a basis for comparative metaproteomic analyses of symbiont-containing versus symbiont-free tissues, both under energy-rich and energy-limited conditions. Our results suggest that metabolic interactions include nutrient allocation from symbiont to host by symbiont digestion and substrate transfer to the symbiont by abundant host proteins. We furthermore propose that Riftia maintains its symbiont by protecting the bacteria from oxidative damage while also exerting symbiont population control. Eukaryote-like symbiont proteins might facilitate intracellular symbiont persistence. Energy limitation apparently leads to reduced symbiont biomass and increased symbiont digestion. Our study provides unprecedented insights into host-microbe interactions that shape this highly efficient symbiosis. ; This work was supported by the German Research Foundation DFG (grant MA 6346/2-1 to S.M., grant BR 5488/1-1 to C.B.), the German Academic Exchange Service DAAD (T.H.), a fellowship of the Institute of Marine Biotechnology Greifswald (T.H.), the Canada Foundation for Innovation, the Government of Alberta and the Natural Sciences and Engineering Research Council of Canada NSERC through a ...

Islands are integral to the earth's biodiversity, with their distinct environments offering a haven for a variety of threatened species of plants, wildlife and unique human cultures. Worldwide, tourism activity profoundly impacts upon destinations, but the impacts on islands are noticeably more acute due to their fragile environments and isolated communities. Research has found that tourism can impact island communities in a variety of ways, including economically, socially and environmentally. Importantly, social interaction is often central to the visitor experience on islands, yet local resentment of tourism development can dilute the tourism experience and inhibit the use of host-guest interaction as a point of market differentiation. Thus this research explores the process and outcomes of host-guest interactions within the context of island tourism. Previous studies on host-guest interaction have assessed the consequences or impacts tourism has on local communities. Social Exchange Theory (SET) has commonly been used as a tool to frame residents' perceptions of the economic, environmental and socio-cultural impacts of tourism. SET consists of four key stages: initiation of exchange; exchange formation; transaction evaluation; and, consequences of exchange. Building on SET as a conceptual framework for host-guest interaction, this research sought to: explore locals' perceptions of host-guest interaction; explore visitors' perceptions of host-guest interaction; and, evaluate visitors' perceptions of the impacts of host-guest interactions on local communities. A mixed methods research design is used to explore host-guest interactions on Bruny and Magnetic Islands, two islands located off the east coast of Australia. This included three sequential phases of data collection: Phase One assessed residents' perceptions of host-guest interactions; Phase Two appraised visitors' perceptions of host-guest interactions; and, Phase Three measured visitors' belief and evaluation of the impact of tourism on the local island communities. This research revealed that locals were motivated to interact with visitors for a variety of reasons, ranging from economic needs through to a desire to deliver meaningful experiences. Similarly, visitors' identified three sets of needs they required from interacting with the local island communities: basic or superficial; meaningful; and, latent needs. Host-guest interactions were facilitated by festivals, events and markets; community clubs and groups; and, business exchanges via employees of local business and government agencies. Barriers to host-guest interaction were perceived to include: social resistance by the community; a lack of support infrastructure and resources; and, deficiencies in opportunities, communication and promotion. Often host-guest interactions consisted of a transaction of money for goods and services, or the exchange of knowledge for status. The island communities viewed tourism development as having positive economic impacts, but negative environmental and socio-cultural impacts which detracted from its benefits. This is in contrast to visitors who perceived tourism activity to positively increase the economic and social impacts for island communities, while having negative environmental impacts. Although visitors acknowledged host-guest interaction can cause negative impacts, generally they considered tourism to positively impact island communities. Notably, visitors' considered the impact of their own visit to be more positive and less negative than the overall impact of tourism on each of the islands. Finally, visitors' recognised that host-guest interaction can influence their behaviour on the islands, citing both positive and negative incidences of behavioural change. This research has important implications for island tourism planning and development. It unearths the intricate and important process of host-guest interactions and also highlights the need to understand the perceptions of both visitors and locals in the sustainable tourism development process.

Viruses control natural microbial communities. Identification of virus–host pairs relies either on their cultivation or on metagenomics and tentative assignment based on genomic signatures. Both approaches have severe drawbacks when aiming to target such pairs within the uncultured majority. Here we present an unambiguous way to assign viruses to hosts that does not rely on any previous information about either of them nor requires their cultivation. First, genomic contents of individual cells present in an environmental sample are retrieved by means of single-cell genomic technologies. Then, individual cell genomes are hybridized against a set of individual viral genomes from the same sample, previously immobilized on a microarray. Infected cells will yield positive hybridization as they carry viral genomes, which can be then sequenced and characterized. Using this method, we pinpoint viruses infecting the ubiquitous hyperhalophilic Nanohaloarchaeota, included in the so-called 'microbial dark matter' (the uncultured fraction of the microbial world). ; This work was supported by the projects CGL2012-39627-C03-01 (to J.A.) and AYA2011-24803 (to V.P.) of the Spanish Ministry of Science and Innovation, which are co-financed with FEDER support from the European Union.

This is the final version of the article. Available from Springer Nature via the DOI in this record. ; Aquatic chytrid fungi threaten amphibian biodiversity worldwide owing to their ability to rapidly expand their geographical distributions and to infect a wide range of hosts. Combating this risk requires an understanding of chytrid host range to identify potential reservoirs of infection and to safeguard uninfected regions through enhanced biosecurity. Here we extend our knowledge on the host range of the chytrid Batrachochytrium dendrobatidis by demonstrating infection of a non-amphibian vertebrate host, the zebrafish. We observe dose-dependent mortality and show that chytrid can infect and proliferate on zebrafish tissue. We also show that infection phenotypes (fin erosion, cell apoptosis and muscle degeneration) are direct symptoms of infection. Successful infection is dependent on disrupting the zebrafish microbiome, highlighting that, as is widely found in amphibians, commensal bacteria confer protection against this pathogen. Collectively, our findings greatly expand the limited tool kit available to study pathogenesis and host response to chytrid infection. ; N.L. is supported by the Lister Institute of Preventive Medicine. J.C. and A.E. were funded by the Welsh Government and Higher Education Funding Council for Wales through the Sêr Cymru National Research Network for Low Carbon, Energy and Environment AquaWales Project. C.R.T. and M.J.D. were funded by the Leverhulme Trust. Work in the Fisher laboratory is supported by the UK Natural Environmental Research Council (NERC NE/K014455/1) and the Leverhulme Trust. Work in the Mostowy laboratory is supported by a Wellcome Trust Research Career Development Fellowship (WT097411MA) and the Lister Institute of Preventive Medicine.

We thank Jose Munoz for his input on the analysis of the mouse RNA-seq enrichment. R.A.F. was supported by a Wellcome Trust-Massachusetts Institute of Technology (MIT) Postdoctoral Fellowship. M.C.F. and J.R. were supported by Medical Research Council grant MR/K000373/1. R.C.M. is supported by a Wolfson Royal Society Research Merit Award and by funding from the European Research Council under the European Union's Seventh Framework Program (FP/2007-2013)/ERC (grant agreement no. 614562). This work was funded in part by NIAID grant U19AI110818 to the Broad Institute. ; Peer reviewed ; Publisher PDF

Abstract Background Fertilisation of land with processed sewage sludges, which often contain low levels of pathogens, endotoxins, and trace amounts of industrial and household chemicals, has become common practice in Western Europe, the US, and Canada. Local governments, however, are increasingly restricting or banning the practice in response to residents reporting adverse health effects. These self-reported illnesses have not been studied and methods for assessing exposures of residential communities to contaminants from processed sewage sludges need to be developed. Methods To describe and document adverse effects reported by residents, 48 individuals at ten sites in the US and Canada were questioned about their environmental exposures and symptoms. Information was obtained on five additional cases where an outbreak of staphylococcal infections occurred near a land application site in Robesonia, PA. Medical records were reviewed in cases involving hospitalisation or other medical treatment. Since most complaints were associated with airborne contaminants, an air dispersion model was used as a means for potentially ruling out exposure to sludge as the cause of adverse effects. Results Affected residents lived within approximately 1 km of land application sites and generally complained of irritation (e.g., skin rashes and burning of the eyes, throat, and lungs) after exposure to winds blowing from treated fields. A prevalence of Staphylococcus aureus infections of the skin and respiratory tract was found. Approximately 1 in 4 of 54 individuals were infected, including 2 mortalities (septicaemia, pneumonia). This result was consistent with the prevalence of S. aureus infections accompanying diaper rashes in which the organism, which is commonly found in the lower human colon, tends to invade irritated or inflamed tissue. Conclusions When assessing public health risks from applying sewage sludges in residential areas, potential interactions of chemical contaminants with low levels of pathogens should be considered. An increased risk of infection may occur when allergic and non-allergic reactions to endotoxins and other chemical components irritate skin and mucus membranes and thereby compromise normal barriers to infection.