1,611 research outputs found

    The novel ECF56 SigG1-RsfG system modulates morphological differentiation and metal-ion homeostasis in Streptomyces tsukubaensis

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    Extracytoplasmic function (ECF) sigma factors are key transcriptional regulators that prokaryotes have evolved to respond to environmental challenges. Streptomyces tsukubaensis harbours 42 ECFs to reprogram stress-responsive gene expression. Among them, SigG1 features a minimal conserved ECF s2–s4 architecture and an additional C-terminal extension that encodes a SnoaL_2 domain, which is characteristic for ECF s factors of group ECF56. Although proteins with such domain organisation are widely found among Actinobacteria, the functional role of ECFs with a fused SnoaL_2 domain remains unknown. Our results show that in addition to predicted self-regulatory intramolecular amino acid interactions between the SnoaL_2 domain and the ECF core, SigG1 activity is controlled by the cognate anti-sigma protein RsfG, encoded by a co-transcribed sigG1-neighbouring gene. Characterisation of ¿sigG1 and ¿rsfG strains combined with RNA-seq and ChIP-seq experiments, suggests the involvement of SigG1 in the morphological differentiation programme of S. tsukubaensis. SigG1 regulates the expression of alanine dehydrogenase, ald and the WhiB-like regulator, wblC required for differentiation, in addition to iron and copper trafficking systems. Overall, our work establishes a model in which the activity of a s factor of group ECF56, regulates morphogenesis and metal-ions homeostasis during development to ensure the timely progression of multicellular differentiation.This work was partially funded by National Funds through FCT-Fundação para a Ciência e a Tecnologia, I.P., under the project ERA-IB-2/0001/2015. It was further supported by FEDER - Fundo Europeu de Desen-volvimento Regional funds through the COMPETE 2020 - Operational Programme for Competitiveness and Internationalisation (POCI), Portugal 2020; and by Portuguese funds through FCT Fundação para a Ciência e a Tecnologia, I.P/Ministério da Ciência, Tecnologia e Ensino Superior POCI-01-0145-FEDER-007274 and NORTE-01-0145-FEDER-000012. BBSRC supported this work through the Institute Strategic Programme grant BB/J004561/1 to the John Innes Centre. The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. R.O. was supported by the FCT fellowship SFRH/ BD/107862/2015 and by the EMBO fellowship ASTF438-2015, M.V.M. was supported by the FCT fellowship SFRH/BPD/95683/2013 and the FCT contract DL57/2016/CP1355/CT0023 and D.C.P. and G.F. were supported through the IMPRS-Mic and the ERASynBio project ECFexpress (BMBF grant 031L0010B). The authors are grateful to Kim Findlay at the Bioimaging platform of the John Innes Centre (JIC, UK) for performing the SEM imaging of S. tsukubaensis samples, Mervyn Bibb (JIC, UK) for the pIJ12333 plasmid , Mark Buttner (JIC, UK) for his comments and discussion regarding the work and Paula Tamagnini (i3S, PT) for comments on the manuscript. The authors acknowledge the support of the i3S Scientific Platforms Cell Culture and Genotyping, Biochemical and Biophysical Technologies and Proteomics

    Comparison of the airway microbiota in children with chronic suppurative lung disease

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    Rationale: The airway microbiota is important in chronic suppurative lung diseases (CSLD), such as primary ciliary dyskinesia (PCD) and cystic fibrosis (CF). This comparison has not previously been described but is important because difference between the two diseases may relate to the differing prognoses and lead to pathological insights and potentially, new treatments. Objectives: To compare the longitudinal development of the airway microbiota in children with PCD to that of CF and relate this to age and clinical status. Methods: Sixty-two age-matched children (age range 0.5–17 years) with PCD or CF (n=31 in each group) were recruited prospectively and followed for 1.1 years. Throat swabs or sputum as well as clinical information were collected at routine clinical appointments. 16S rRNA gene sequencing was performed. Measurements and Main Results: The microbiota was highly individual and more diverse in PCD and differed in community composition when compared with CF. Whilst Streptococcus was the most abundant genus in both conditions, Pseudomonas was more abundant in CF with Haemophilus more abundant in PCD (Padj=0.0005). In PCD only, an inverse relationship was seen in the relative abundance of Streptococcus and Haemophilus with age. Conclusions: Bacterial community composition differs between children with PCD and those with CF. Pseudomonas is more prevalent in CF and Haemophilus in PCD, at least until infection with Pseudomonas supervenes. Interactions between organisms, particularly members of Haemophilus, Streptococcus, and Pseudomonas genera appear important. Study of the interactions between these organisms may lead to new therapies or risk stratification

    Identification of patients with atrial fibrillation in UK community pharmacy: an evaluation of a new service

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    Background: Many patients with atrial fibrillation (AF) are asymptomatic and diagnosed via opportunistic screening. Community pharmacy has been advocated as a potential resource for opportunistic screening and lifestyle interventions.  Objective: The objective of this evaluation is to describe the outcomes from an AF service, in terms of referrals and interventions provided to patients identified as not at risk.  Method: Eligibility was assessed from pharmacy records and the completion of a short questionnaire. Once consented, patients were screened for AF and their blood pressure was measured.  Results: Of 594 patients screened, nine were identified as at risk of having AF and were referred to their GP. The service also identified 109 patients with undiagnosed hypertension, 176 patients with a Body Mass Index (BMI) > 30, 131 with an Audit-C score > 5 and 59 smokers. Pharmacists provided 413 interventions in 326 patients aimed at weight reduction (239), alcohol consumption (123) and smoking cessation (51).  Conclusion: This evaluation characterises the interventions provided to, not only those identified with the target condition - in this case AF - but also those without it. The true outcome of these additional interventions, along with appropriate follow-up, should be the focus of future studies.Impact of findings on patients or practice •Patients are willing to be screened for AF through community pharmacies•Screening can provide opportunities to identify other healthcare problems such a hypertension or poor lifestyle •Community pharmacists are able to provide brief advice to patients as a result of this opportunistic screenin

    Functional diversity of marine ecosystems after the Late Permian mass extinction event

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    Article can be accessed from http://www.nature.com/ngeo/journal/v7/n3/full/ngeo2079.htmlThe Late Permian mass extinction event was the most severe such crisis of the past 500 million years and occurred during an episode of global warming. It is assumed to have had significant ecological impact, but its effects on marine ecosystem functioning are unknown and the patterns of marine recovery are debated. We analysed the fossil occurrences of all known Permian-Triassic benthic marine genera and assigned each to a functional group based on their inferred life habit. We show that despite the selective extinction of 62-74% of marine genera there was no significant loss of functional diversity at the global scale, and only one novel mode of life originated in the extinction aftermath. Early Triassic marine ecosystems were not as ecologically depauperate as widely assumed, which explains the absence of a Cambrian-style Triassic radiation in higher taxa. Functional diversity was, however, significantly reduced in particular regions and habitats, such as tropical reefs, and at these scales recovery varied spatially and temporally, probably driven by migration of surviving groups. Marine ecosystems did not return to their pre-extinction state, however, and radiation of previously subordinate groups such as motile, epifaunal grazers led to greater functional evenness by the Middle Triassic

    Impact of calcium on salivary α-amylase activity, starch paste apparent viscosity and thickness perception

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    Thickness perception of starch-thickened products during eating has been linked to starch viscosity and salivary amylase activity. Calcium is an essential cofactor for α-amylase and there is anecdotal evidence that adding extra calcium affects amylase activity in processes like mashing of beer. The aims of this paper were to (1) investigate the role of salivary calcium on α-amylase activity and (2) to measure the effect of calcium concentration on apparent viscosity and thickness perception when interacting with salivary α-amylase in starch-based samples. α-Amylase activity in saliva samples from 28 people was assessed using a typical starch pasting cycle (up to 95 °C). The activity of the enzyme (as measured by the change in starch apparent viscosity) was maintained by the presence of calcium, probably by protecting the enzyme from heat denaturation. Enhancement of α-amylase activity by calcium at 37 °C was also observed although to a smaller extent. Sensory analysis showed a general trend of decreased thickness perception in the presence of calcium, but the result was only significant for one pair of samples, suggesting a limited impact of calcium enhanced enzyme activity on perceived thickness

    Evolution of Novel Signal Traits in the Absence of Female Preferences in Neoconocephalus Katydids (Orthoptera, Tettigoniidae)

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    Background Significance: Communication signals that function to bring together the sexes are important for maintaining reproductive isolation in many taxa. Changes in male calls are often attributed to sexual selection, in which female preferences initiate signal divergence. Natural selection can also influence signal traits if calls attract predators or parasitoids, or if calling is energetically costly. Neutral evolution is often neglected in the context of acoustic communication. Methodology/Principal Findings: We describe a signal trait that appears to have evolved in the absence of either sexual or natural selection. In the katydid genus Neoconocephalus, calls with a derived pattern in which pulses are grouped into pairs have evolved five times independently. We have previously shown that in three of these species, females require the double pulse pattern for call recognition, and hence the recognition system of the females is also in a derived state. Here we describe the remaining two species and find that although males produce the derived call pattern, females use the ancestral recognition mechanism in which no pulse pattern is required. Females respond equally well to the single and double pulse calls, indicating that the derived trait is selectively neutral in the context of mate recognition. Conclusions/Significance: These results suggest that 1) neutral changes in signal traits could be important in the diversification of communication systems, and 2) males rather than females may be responsible for initiating signa

    Kartagener syndrome

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    The influence of parental smoking and family type on saliva cotinine in UK ethnic minority children: a cross sectional study

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    Background In the United Kingdom, there has been an increase in cigarette smoking in ethnic minority adults since the 1970s; in some groups levels are now similar to that of White British people. We aimed to examine the determinants of exposure to secondhand smoke in ethnic minority children. We hypothesised that exposure to secondhand smoke in children will vary across ethnic groups, but that the correlates of exposure would be similar to that of Whites. Methods The Determinants of Adolescent Social well-being and Health sample comprises 3468 White United Kingdom and ethnic minority (Black Caribbean, Black African, Indian, Pakistani, Bangladeshi) pupils aged 11-13 yrs. Outcome was saliva cotinine concentration. Explanatory variables collected by self-complete questionnaire included ethnicity, child reported household smoking and socio-economic circumstances. Data were analysed using linear regression models with a random intercept function. Results Ethnic minority children had lower saliva cotinine than Whites, partly explained by less smoking among parents. White and Black Caribbean children had higher cotinine levels if they lived in a household with a maternal smoker only, than with a paternal smoker only. Living in a lone compared to a dual parent household was associated with increased cotinine concentration of 45% (95%CI 5, 99%) in Whites, 27% (95%CI 5,53%) in Black Caribbeans and 21% (95%CI 1, 45%) in Black Africans after adjusting for household smoking status. Material disadvantage was a significant correlate only for White children (40% (95%CI 1, 94%) increase in cotinine in least compared to most advantaged group). Conclusions Ethnic minority children were less exposed to secondhand smoke than Whites, but the variations within groups were similarly patterned. These findings suggest that it is important not to be complacent about low smoking prevalence in some minority groups

    Subtidal macrozoobenthos communities from northern Chile during and post El Niño 1997–1998

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    Despite a large amount of climatic and oceanographic information dealing with the recurring climate phenomenon El Niño (EN) and its well known impact on diversity of marine benthic communities, most published data are rather descriptive and consequently our understanding of the underlying mechanisms and processes that drive community structure during EN are still very scarce. In this study, we address two questions on the effects of EN on macrozoobenthic communities: (1) how does EN affect species diversity of the communities in northern Chile? and (2) is EN a phenomenon that restarts community assembling processes by affecting species interactions in northern Chile? To answer these questions, we compared species diversity and co-occurrence patterns of soft-bottoms macrozoobenthos communities from the continental shelf off northern Chile during (March 1998) and after (September 1998) the strong EN event 1997–1998. The methods used varied from species diversity and species co-occurrence analyses to multivariate ordination methods. Our results indicate that EN positively affects diversity of macrozoobenthos communities in the study area, increasing the species richness and diversity and decreasing the species dominance. EN represents a strong disturbance that affects species interactions that rule the species assembling processes in shallow-water, sea-bottom environments
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