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Ticks have relatively complex microbiomes, but only a small proportion of the bacterial symbionts recorded from ticks are vertically transmitted. Moreover, co-cladogenesis between ticks and their symbionts, indicating an intimate relationship over evolutionary history driven by a mutualistic association, is the exception rather than the rule. One of the most widespread tick symbionts is Candidatus Midichloria, which has been detected in all of the major tick genera of medical and veterinary importance. In some species of Ixodes, such as the sheep tick Ixodes ricinus (infected with Candidatus Midichloria mitochondrii), the symbiont is fixed in wild adult female ticks, suggesting an obligate mutualism. However, almost no information is available on genetic variation in Candidatus M. mitochondrii or possible co-cladogenesis with its host across its geographic range. Here, we report the first survey of Candidatus M. mitochondrii in I. ricinus in Great Britain and a multi-locus sequence typing (MLST) analysis of tick and symbiont between British ticks and those collected in continental Europe. We show that while the prevalence of the symbiont in nymphs collected in England is similar to that reported from the continent, a higher prevalence in nymphs and adult males is apparent in Wales. In general, Candidatus M. mitochondrii exhibits very low levels of sequence diversity, although a consistent signal of host-symbiont coevolution was apparent in Scotland. Moreover, the tick MLST scheme revealed that Scottish specimens form a clade that is partially separated from other British ticks, with almost no contribution of continental sequence types in this north-westerly border of the tick's natural range. The low diversity of Candidatus M. mitochondrii, in contrast with previously reported high rates of polymorphism in I. ricinus mitogenomes, suggests that the symbiont may have swept across Europe recently via a horizontal, rather than vertical, transmission route., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

Much of the developing world and areas of the developed world suffer water vulnerability. Engineering solutions enable technically efficient extraction and diversion of water towards areas of demand but, without rebalancing resource regeneration, can generate multiple adverse ecological and human consequences. The Banas River, Rajasthan (India), has been extensively developed for water diversion, particularly from the Bisalpur Dam from which water is appropriated by powerful urban constituencies dispossessing local people. Coincidentally, abandonment of traditional management, including groundwater recharge practices, is leading to increasingly receding and contaminated groundwater. This creates linked vulnerabilities for rural communities, irrigation schemes, urban users, dependent ecosystems and the multiple ecosystem services that they provide, compounded by climate change and population growth. This paper addresses vulnerabilities created by fragmented policy measures between rural development, urban and irrigation water supply and downstream consequences for people and wildlife. Perpetuating narrowly technocentric approaches to resource exploitation is likely only to compound emerging problems. Alternatively, restoration or innovation of groundwater recharge practices, particularly in the upper catchment, can represent a proven, ecosystem-based approach to resource regeneration with linked beneficial socio-ecological benefits. Hybridising an ecosystem-based approach with engineered methods can simultaneously increase the security of rural livelihoods, piped urban and irrigation supplies, and the vitality of river ecosystems and their services to beneficiaries. A renewed policy focus on local-scale water recharge practices balancing water extraction technologies is consistent with emerging Rajasthani policies, particularly Jal Swavlamban Abhiyan ('water self-reliance mission'). Policy reform emphasising recharge can contribute to water security and yield socio-economic outcomes through a systemic understanding of how the water system functions, and by connecting goals and budgets across multiple, currently fragmented policy areas. The underpinning principles of this necessary paradigm shift are proven and have wider geographic relevance, though context-specific research is required to underpin robust policy and practical implementation., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Diets rich in n-3 polyunsaturated fatty acids (PUFAs) are associated with suppression of cell-mediated immune responses, but the mechanisms are unclear. We hypothesized that n-3 PUFAs can inhibit the function of human antigen-presenting cells. A prerequisite for this role of blood monocytes is the cell surface expression of major histocompatibility complex (MHC) class II molecules [human leukocyte antigen (HLA)-DR, -DP, and -DQ], aided by the presence of intercellular adhesion molecule-1 (ICAM-1) and leukocyte function associated antigens 1 and 3. We showed previously that the n-3 PUFA eicosapentaenoic acid (EPA) inhibits the expression of HLA-DR on unstimulated human monocytes in vitro, but that docosahexaenoic acid (DHA) enhances its expression. However, both n-3 PUFAs suppress the expression of HLA-DR, HLA-DP, and ICAM-1 on interferon-gamma-activated monocytes. We also established that dietary fish-oil supplementation can inhibit the expression of these surface molecules on circulating human monocytes. We subsequently showed that when EPA and DHA were combined in the same ratio as is commonly found in fish-oil-supplement capsules (3:2), there was no significant effect in vitro on the expression of HLA-DR on unstimulated monocytes, but the expression on activated monocytes remained significantly inhibited. In the same in vitro system, the ability of activated monocytes to present antigen to autologous lymphocytes was significantly reduced after culture with the combined n-3 PUFAs. These findings provide one potential mechanism for the beneficial effect of fish oil in the treatment of rheumatoid arthritis, a disorder associated with elevated expression of MHC class II and adhesion molecules on monocytes present within affected joints.

Although there is strong epidemiologic evidence that diets rich in carotenoids such as beta-carotene are associated with a reduced incidence of cancer, the cellular mechanisms underlying this phenomenon remain unknown. This article describes the effect of dietary beta-carotene supplementation on both the expression of functionally associated surface molecules on human monocytes and on the secretion of the cytokine tumor necrosis factor-alpha (TNF-alpha) by monocytes, all of which are involved in the initiation and regulation of immune responses involved in tumor surveillance. A double-blind, placebo-controlled, crossover study was undertaken in which 25 healthy, adult male nonsmokers were randomly assigned to receive beta-carotene (15 mg daily) or placebo for 26 days, followed by the alternative treatment for a further 26 days. The expression of functionally related monocyte surface molecules was quantified by flow cytometry, and ex vivo secretion of TNF-alpha was quantified by an enzyme-linked immunosorbent assay, before and after each treatment period. After dietary supplementation there were significant increases in plasma levels of beta-carotene and in the percentages of monocytes expressing the major histocompatibility complex class II molecule HLA-DR and the adhesion molecules intercellular adhesion molecule-1 and leukocyte function-associated antigen-3. In addition, the ex vivo TNF-alpha secretion by blood monocytes was significantly increased after supplementation. These findings suggest that moderate increases in the dietary intake of beta-carotene can enhance cell-mediated immune responses within a relatively short period of time, providing a potential mechanism for the anticarcinogenic properties attributed to beta-carotene.

Diets rich in (n-3) polyunsaturated fatty acids (PUFA) are associated with suppression of the immune system, but the mechanisms are unclear. Specific immune responses are initiated by antigen-presenting cells. This study examines the in vitro effect of the (n-3) PUFA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the expression of cell surface molecules required for normal antigen-presenting cell function on human blood monocytes. Monocytes were incubated with or without EPA or DHA for 48 h at 37 degrees C. Following incubation, expression of major histocompatibility complex (MHC) class II molecules (HLA-DR, -DP and -DQ) and adhesion molecules [intercellular adhesion molecule-1 (ICAM-1) and leucocyte function associated antigen-1] was quantified by flow cytometry. In the presence of EPA alone there was a significantly lower median intensity of expression of HLA-DR and ICAM-1 relative to incubations without EPA. In contrast, significantly greater median intensities of expression of HLA-DR and -DP were observed following incubation with DHA. In parallel experiments, where monocytes were simultaneously activated by the addition of interferon-gamma to the cultures, median expression intensities of HLA-DR, -DP and ICAM-1 were significantly lower in the presence of either EPA or DHA compared with incubations without the (n-3) PUFA. These findings support previous animal studies that suggest that (n-3) PUFA can influence immune reactivity by modulating antigen-presenting cell function.

To test the hypothesis that fish oil supplementation can inhibit the expression of functionally associated molecules on the surface of human blood monocytes, we randomly assigned 12 healthy adults to receive either an n-3 polyunsaturated fatty acid-rich fish oil supplement for 21 d or to receive no supplement. The percentage of monocytes expressing major histocompatibility complex (MHC) class II molecules (HLA-DR, -DP, and -DQ), intercellular adhesion molecule-1, and leukocyte-function-associated antigen-1, and the intensity of expression of each molecule were quantified before and after the study period. Monocytes were examined immediately after blood sampling and again after incubation in serum-free culture medium for 24 h in the presence of interferon-gamma to up-regulate expression of MHC class II molecules by the monocytes. The intensity of expression of all the monocyte surface molecules examined was significantly reduced after fish oil supplementation (P < 0.025), although there was no change in the percentage of monocytes expressing each molecule. After incubation with interferon-gamma, there was a similar inhibition of surface molecule expression (with the exception of HLA-DQ) by monocytes from the fish oil-supplemented group, and there was a reduction in the percentage of monocytes expressing both HLA-DR and -DP molecules (P < 0.025). No significant changes were observed in the reference group. Dietary supplementation with fish oil can inhibit the expression of surface molecules involved in the function of human antigen-presenting cells, a potential mechanism by which n-3 fatty acids may suppress cell-mediated immune responses.

The frog ear can be modelled as two coupled eardrums with an additional sound pathway through the mouth cavity. In a previous version of this model, with realistic parameters, we were able to account very well for empirical measurements of the eardrum vibration under free- and closed-field acoustic conditions. This earlier model does not, however, adequately predict the directional characteristics of the frog ear as determined empirically. In this paper we present a modified model which will account for the directionality together with the free- and closed-field frequency responses, and which is also consistent with anatomical considerations.