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Tsetse-transmitted African trypanosomes must develop into mammalian-infectious metacyclic cells in the fly's salivary glands (SGs) before transmission to a new host. The molecular mechanisms that underlie this developmental process, known as metacyclogenesis, are poorly understood. Blocking the few metacyclic parasites deposited in saliva from further development in the mammal could prevent disease. To obtain an in-depth perspective of metacyclogenesis, we performed single-cell RNA sequencing (scRNA-seq) from a pool of 2,045 parasites collected from infected tsetse SGs. Our data revealed three major cell clusters that represent the epimastigote, and pre- and mature metacyclic trypanosome developmental stages. Individual cell level data also confirm that the metacyclic pool is diverse, and that each parasite expresses only one of the unique metacyclic variant surface glycoprotein (mVSG) coat protein transcripts identified. Further clustering of cells revealed a dynamic transcriptomic and metabolic landscape reflective of a developmental program leading to infectious metacyclic forms preadapted to survive in the mammalian host environment. We describe the expression profile of proteins that regulate gene expression and that potentially play a role in metacyclogenesis. We also report on a family of nonvariant surface proteins (Fam10) and demonstrate surface localization of one member (named SGM1.7) on mature metacyclic parasites. Vaccination of mice with recombinant SGM1.7 reduced parasitemia early in the infection. Future studies are warranted to investigate Fam10 family proteins as potential trypanosome transmission blocking vaccine antigens. Our experimental approach is translationally relevant for developing strategies to prevent other insect saliva-transmitted parasites from infecting and causing disease in mammalian hosts.
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Insetos Vetores/parasitologia , Proteínas de Protozoários/genética , Trypanosoma brucei brucei/crescimento & desenvolvimento , Trypanosoma brucei brucei/genética , Moscas Tsé-Tsé/parasitologia , Animais , Feminino , Humanos , Estágios do Ciclo de Vida , Camundongos , Camundongos Endogâmicos BALB C , Proteínas de Protozoários/imunologia , RNA de Protozoário/genética , Glândulas Salivares/parasitologia , Análise de Sequência de RNA , Análise de Célula Única , Transcriptoma , Trypanosoma brucei brucei/imunologia , Tripanossomíase Africana/imunologia , Tripanossomíase Africana/parasitologiaRESUMO
BACKGROUND: Pacific Island countries, many of which are low- and middle-income countries, have some of the highest rates of diet-related non-communicable diseases (DR-NCDs) globally. These countries also face some of the earliest and most significant impacts of climate change. Several pathways between climate change and DR-NCDs have been described in the literature; however, the scope is broad and lacks context specificity. This paper uses a case study of one Pacific Island country, Vanuatu, to investigate links between climate change and DR-NCDs. METHODS: An ethnographic qualitative research approach was used to share the lived experiences of community participants and to explore and contrast these with the perspectives of key informants at the national level. Data collection comprised thirty-two semi-structured interviews and community fieldwork in two villages using a mix of methods, including group workshops, informal conversations, and observations. Reflexive thematic analysis was conducted on both data sets. RESULTS: This study found that DR-NCDs are a prominent health concern for ni-Vanuatu people and that structural determinants, including climate change, are the main driving forces for increased DR-NCD risk in the country. However, there was a lack of understanding of the links between climate change and DR-NCDs both at the community and national levels. Structural factors, such as social determinants and climate change, constrained individual and community agency in making optimal food and health choices and promoted the nutrition transition in Vanuatu. Despite the critical role of social determinants and climate change in driving DR-NCD risk, the responsibility for prevention and treatment was considered to rest mainly with the individual. A systems approach is advocated to grasp the complexity and interrelatedness of the causes of DR-NCD risk. CONCLUSIONS: The interaction of structural determinants creates food and health environments that amplify the risk, burden, and consequences of DR-NCDs. It is recommended that the DR-NCD narrative in Vanuatu be re-framed with an emphasis on the range of structural determinants of DR-NCD risk. This will serve to enhance individual and collective agency to not only make healthy food and other behavioural choices but also to exercise agency to transform the structures in a culturally appropriate way.
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Doenças não Transmissíveis , Mudança Climática , Dieta , Humanos , Renda , Doenças não Transmissíveis/epidemiologia , Doenças não Transmissíveis/prevenção & controle , Ilhas do Pacífico , Pesquisa Qualitativa , VanuatuRESUMO
AIM: Regular reflective practice within a large group setting has been shown to reduce levels of burnout in healthcare professionals. We describe how regular reflective rounds were designed and implemented within an existing educational program at a UK children's hospital and report on the feedback received from participants. METHODS: Eight face-to-face reflective rounds took place in Southampton Children's Hospital, UK, from September 2017 to February 2020 with a further virtual round in July 2020 during the COVID-19 pandemic. Each round was facilitated by a clinical psychologist and consultant. For each round, up to three volunteer panellists from different staff groups were invited to share their personal experiences on a pre-selected subject to the large group. The group would then contribute to the discussion by offering their own reflections. Feedback forms were distributed to attendees and collated. RESULTS: Eight rounds were held with mean attendance of 32 (range 19-47). Across the eight rounds, the total attendance was 256 staff members. The virtual round had 20 participants. Feedback was received from 202 participants. The majority (98%) would recommend the rounds to colleagues with 64 participants (32%) rating the rounds as 'exceptional' and 91 (45%) as 'excellent'. The virtual round received similar positive feedback. CONCLUSION: Large group reflective practice can be implemented within an existing regular educational program. Rounds have been well received by participants and are likely to be of relevance and value to other healthcare groups. The rounds can also be delivered effectively virtually, which may increase participation.
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COVID-19 , Visitas de Preceptoria , Criança , Hospitais Pediátricos , Humanos , Pandemias , SARS-CoV-2RESUMO
The frequency and intensity of hurricanes are increasing globally, and anthropogenic modifications in cities have created systems that may be particularly vulnerable to their negative effects. Organisms living in cities are exposed to variable levels of chronic environmental stress. However, whether chronic stress ameliorates or exacerbates the negative effects of hurricanes remains an open question. Here, we consider two hypotheses about the simultaneous consequences of acute disturbances from hurricanes and chronic stress from urbanization for the structure of urban arthropod communities. The tipping point hypothesis posits that organisms living in high stress habitats are less resilient than those in low stress habitats because they are living near the limits of their environmental tolerances; while the disturbance tolerance hypothesis posits that high stress habitats host organisms pre-adapted for coping with disturbance, making them more resilient to the effects of storms. We used a before-after-control-impact design in the street medians and city parks of Manhattan (New York City, New York, USA) to compare arthropod communities before and after Super Storm Sandy in sites that were flooded and unflooded during the storm. Our evidence supported the disturbance tolerance hypothesis. Significant compositional differences between street medians and city parks before the storm disappeared after the storm; similarly, unflooded city parks had significantly different arthropod composition while flooded sites were indistinguishable. These differences were driven by reduced occurrences and abundances of arthropods in city parks. Finally, those arthropod groups that were most tolerant to urban stress were also the most tolerant to flooding. Our results suggest that the species that survive in high stress environments are likely to be the ones that thrive in response to acute disturbance. As storms become increasingly common and extreme, this juxtaposition in responses to storm-associated disturbance may lead to diversity loss in cities, potentially leading entire urban landscapes to mirror the reduced diversity of street medians.
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Artrópodes , Biodiversidade , Tempestades Ciclônicas , Parques Recreativos , Urbanização , Animais , Cidade de Nova Iorque , Estresse FisiológicoRESUMO
Skin microbes play a role in human body odour, health and disease. Compared with gut microbes, we know little about the changes in the composition of skin microbes in response to evolutionary changes in hosts, or more recent behavioural and cultural changes in humans. No studies have used sequence-based approaches to consider the skin microbe communities of gorillas and chimpanzees, for example. Comparison of the microbial associates of non-human primates with those of humans offers unique insights into both the ancient and modern features of our skin-associated microbes. Here we describe the microbes found on the skin of humans, chimpanzees, gorillas, rhesus macaques and baboons. We focus on the bacterial and archaeal residents in the axilla using high-throughput sequencing of the 16S rRNA gene. We find that human skin microbial communities are unique relative to those of other primates, in terms of both their diversity and their composition. These differences appear to reflect both ancient shifts during millions of years of primate evolution and more recent changes due to modern hygiene.
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Microbiota , Primatas/microbiologia , Pele/microbiologia , Animais , Biodiversidade , Evolução Biológica , Gorilla gorilla/microbiologia , Humanos , Macaca mulatta/microbiologia , Pan troglodytes/microbiologia , Papio/microbiologia , RNA Arqueal/química , RNA Bacteriano/química , RNA Ribossômico/químicaRESUMO
[This corrects the article DOI: 10.1098/rspb.2015.2586.].
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The insect gut is lined by a protective, chitinous peritrophic matrix (PM) that separates immunoreactive epithelial cells from microbes present within the luminal contents. Tsetse flies (Glossina spp.) imbibe vertebrate blood exclusively and can be exposed to foreign microorganisms during the feeding process. We used RNA interference-based reverse genetics to inhibit the production of a structurally robust PM and then observed how this procedure impacted infection outcomes after per os challenge with exogenous bacteria (Enterobacter sp. and Serratia marcescens strain Db11) and parasitic African trypanosomes. Enterobacter and Serratia proliferation was impeded in tsetse that lacked an intact PM because these flies expressed the antimicrobial peptide gene, attacin, earlier in the infection process than did their counterparts that housed a fully developed PM. After challenge with trypanosomes, attacin expression was latent in tsetse that lacked an intact PM, and these flies were thus highly susceptible to parasite infection. Our results suggest that immunodeficiency signaling pathway effectors, as opposed to reactive oxygen intermediates, serve as the first line of defense in tsetse's gut after the ingestion of exogenous microorganisms. Furthermore, tsetse's PM is not a physical impediment to infection establishment, but instead serves as a barrier that regulates the fly's ability to immunologically detect and respond to the presence of these microbes. Collectively, our findings indicate that effective insect antimicrobial responses depend largely upon the coordination of multiple host and microbe-specific developmental factors.
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Enterobacter/imunologia , Trato Gastrointestinal/imunologia , Serratia marcescens/imunologia , Trypanosoma brucei brucei/imunologia , Moscas Tsé-Tsé/imunologia , Animais , Quitina/metabolismo , Enterobacter/fisiologia , Células Epiteliais/imunologia , Células Epiteliais/microbiologia , Células Epiteliais/parasitologia , Trato Gastrointestinal/microbiologia , Trato Gastrointestinal/parasitologia , Expressão Gênica/imunologia , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Proteínas de Insetos/genética , Proteínas de Insetos/imunologia , Proteínas de Insetos/metabolismo , Microscopia de Fluorescência , Interferência de RNA , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Serratia marcescens/fisiologia , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Trypanosoma brucei brucei/fisiologia , Moscas Tsé-Tsé/genética , Moscas Tsé-Tsé/metabolismoRESUMO
The amount of energy consumed within an average city block is an order of magnitude higher than that consumed in any other ecosystem over a similar area. This is driven by human food inputs, but the consequence of these resources for urban animal populations is poorly understood. We investigated the role of human foods in ant diets across an urbanization gradient in Manhattan using carbon and nitrogen stable isotopes. We found that some-but not all-ant species living in Manhattan's most urbanized habitats had δ(13)C signatures associated with processed human foods. In particular, pavement ants (Tetramorium sp. E) had increased levels of δ(13)C similar to δ(13)C levels in human fast foods. The magnitude of this effect was positively correlated with urbanization. By contrast, we detected no differences in δ(15)N, suggesting Tetramorium feeds at the same trophic level despite shifting to human foods. This pattern persisted across the broader ant community; species in traffic islands used human resources more than park species. Our results demonstrate that the degree urban ants exploit human resources changes across the city and among species, and this variation could play a key role in community structure and ecosystem processes where human and animal food webs intersect.
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Formigas/fisiologia , Dieta , Cadeia Alimentar , Animais , Isótopos de Carbono/análise , Cidades , Comportamento Alimentar , Humanos , Cidade de Nova Iorque , Isótopos de Nitrogênio/análiseRESUMO
Urban green spaces provide ecosystem services to city residents, but their management is hindered by a poor understanding of their ecology. We examined a novel ecosystem service relevant to urban public health and esthetics: the consumption of littered food waste by arthropods. Theory and data from natural systems suggest that the magnitude and resilience of this service should increase with biological diversity. We measured food removal by presenting known quantities of cookies, potato chips, and hot dogs in street medians (24 sites) and parks (21 sites) in New York City, USA. At the same sites, we assessed ground-arthropod diversity and abiotic conditions, including history of flooding during Hurricane Sandy 7 months prior to the study. Arthropod diversity was greater in parks (on average 11 hexapod families and 4.7 ant species per site), than in medians (nine hexapod families and 2.7 ant species per site). However, counter to our diversity-based prediction, arthropods in medians removed 2-3 times more food per day than did those in parks. We detected no effect of flooding (at 19 sites) on this service. Instead, greater food removal was associated with the presence of the introduced pavement ant (Tetramorium sp. E) and with hotter, drier conditions that may have increased arthropod metabolism. When vertebrates also had access to food, more was removed, indicating that arthropods and vertebrates compete for littered food. We estimate that arthropods alone could remove 4-6.5 kg of food per year in a single street median, reducing its availability to less desirable fauna such as rats. Our results suggest that species identity and habitat may be more relevant than diversity for predicting urban ecosystem services. Even small green spaces such as street medians provide ecosystem services that may complement those of larger habitat patches across the urban landscape.
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Artrópodes/fisiologia , Ecossistema , Cadeia Alimentar , Animais , Biodiversidade , Cidades , Comportamento Alimentar , Cidade de Nova Iorque , Resíduos Sólidos/análise , Especificidade da Espécie , Vertebrados/fisiologiaRESUMO
Urban evolutionary ecology is inherently interdisciplinary. Moreover, it is a field with global significance. However, bringing researchers and resources together across fields and countries is challenging. Therefore, an online collaborative research hub, where common methods and best practices are shared among scientists from diverse geographic, ethnic, and career backgrounds would make research focused on urban evolutionary ecology more inclusive. Here, we describe a freely available online research hub for toolkits that facilitate global research in urban evolutionary ecology. We provide rationales and descriptions of toolkits for: (1) decolonizing urban evolutionary ecology; (2) identifying and fostering international collaborative partnerships; (3) common methods and freely-available datasets for trait mapping across cities; (4) common methods and freely-available datasets for cross-city evolutionary ecology experiments; and (5) best practices and freely available resources for public outreach and communication of research findings in urban evolutionary ecology. We outline how the toolkits can be accessed, archived, and modified over time in order to sustain long-term global research that will advance our understanding of urban evolutionary ecology.
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BACKGROUND AND AIMS: In complex communities, organisms often form mutualisms with multiple different partners simultaneously. Non-additive effects may emerge among species linked by these positive interactions. Ants commonly participate in mutualisms with both honeydew-producing insects (HPI) and their extrafloral nectary (EFN)-bearing host plants. Consequently, HPI and EFN-bearing plants may experience non-additive benefits or costs when these groups co-occur. The outcomes of these interactions are likely to be influenced by variation in preferences among ants for honeydew vs. nectar. In this study, a test was made for non-additive effects on HPI and EFN-bearing plants resulting from sharing exotic ant guards. Preferences of the dominant exotic ant species for nectar vs. honeydew resources were also examined. METHODS: Ant access, HPI and nectar availability were manipulated on the EFN-bearing shrub, Morinda citrifolia, and ant and HPI abundances, herbivory and plant growth were assessed. Ant-tending behaviours toward HPI across an experimental gradient of nectar availability were also tracked in order to investigate mechanisms underlying ant responses. KEY RESULTS: The dominant ant species, Anoplolepis gracilipes, differed from less invasive ants in response to multiple mutualists, with reductions in plot-wide abundances when nectar was reduced, but no response to HPI reduction. Conversely, at sites where A. gracilipes was absent or rare, abundances of less invasive ants increased when nectar was reduced, but declined when HPI were reduced. Non-additive benefits were found at sites dominated by A. gracilipes, but only for M. citrifolia plants. Responses of HPI at these sites supported predictions of the non-additive cost model. Interestingly, the opposite non-additive patterns emerged at sites dominated by other ants. CONCLUSIONS: It was demonstrated that strong non-additive benefits and costs can both occur when a plant and herbivore share mutualist partners. These findings suggest that broadening the community context of mutualism studies can reveal important non-additive effects and increase understanding of the dynamics of species interactions.
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Ecossistema , Insetos/fisiologia , Morinda/fisiologia , Néctar de Plantas/metabolismo , Simbiose , Animais , Comportamento Animal , Espécies Introduzidas , Densidade Demográfica , SamoaRESUMO
Urbanization, among the most widespread and multifaceted anthropogenic change drivers, exerts strong influences on a diversity of ecological communities worldwide. We have begun to understand how urbanization affects species diversity, yet we still have limited knowledge about the ways that species interactions are altered by urbanization. We have an especially poor understanding of how urbanization influences stress-buffering mutualisms, despite the high levels of multivariate stress that urban organisms must overcome and the importance of these interactions to the fitness of many organisms. In this study, we investigated the effects of urbanization on a mutualism between tree cholla cacti (Cylindropuntia imbricata) and visiting ants. We first examined how plant size, ant species composition, and ant activity varied on C. imbricata across an urbanization gradient (urban, suburban, wild) in and around Albuquerque, NM. Ant species composition and activity varied significantly across the urbanization gradient, with ant communities from wildlands having the highest activity and the most dissimilar species composition compared to both suburban and urban sites. In contrast, plant size remained constant regardless of site type. We then experimentally assessed how nectar levels influenced ant aggressive encounters with proxy prey (Drosophila melanogaster larvae) on C. imbricata across urban and wild sites. Ants were more likely to discover, attack, and remove proxy prey in wild sites compared to urban sites; they also performed these behaviors more quickly in wild sites. Nectar supplementation had weaker effects on ant aggression than urbanization, but consistently increased the speed at which aggressive behaviors occurred. Future studies that examine nectar quality and herbivorous arthropod abundance may help explain why this strong difference in ant composition and aggression was not associated with lower plant fitness proxies (i.e. size traits). Nevertheless, this study provides unique insight into the growing body of work demonstrating that mutualisms vary significantly across urbanization gradients.
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Formigas , Urbanização , Animais , Árvores , Néctar de Plantas , Simbiose , Drosophila melanogaster , PlantasRESUMO
Research on the evolutionary ecology of urban areas reveals how human-induced evolutionary changes affect biodiversity and essential ecosystem services. In a rapidly urbanizing world imposing many selective pressures, a time-sensitive goal is to identify the emergent issues and research priorities that affect the ecology and evolution of species within cities. Here, we report the results of a horizon scan of research questions in urban evolutionary ecology submitted by 100 interdisciplinary scholars. We identified 30 top questions organized into six themes that highlight priorities for future research. These research questions will require methodological advances and interdisciplinary collaborations, with continued revision as the field of urban evolutionary ecology expands with the rapid growth of cities.
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Ecossistema , Urbanização , Biodiversidade , Cidades , Ecologia/métodos , HumanosRESUMO
Cities are uniquely complex systems regulated by interactions and feedbacks between nature and human society. Characteristics of human society-including culture, economics, technology and politics-underlie social patterns and activity, creating a heterogeneous environment that can influence and be influenced by both ecological and evolutionary processes. Increasing research on urban ecology and evolutionary biology has coincided with growing interest in eco-evolutionary dynamics, which encompasses the interactions and reciprocal feedbacks between evolution and ecology. Research on both urban evolutionary biology and eco-evolutionary dynamics frequently focuses on contemporary evolution of species that have potentially substantial ecological-and even social-significance. Still, little work fully integrates urban evolutionary biology and eco-evolutionary dynamics, and rarely do researchers in either of these fields fully consider the role of human social patterns and processes. Because cities are fundamentally regulated by human activities, are inherently interconnected and are frequently undergoing social and economic transformation, they represent an opportunity for ecologists and evolutionary biologists to study urban "socio-eco-evolutionary dynamics." Through this new framework, we encourage researchers of urban ecology and evolution to fully integrate human social drivers and feedbacks to increase understanding and conservation of ecosystems, their functions and their contributions to people within and outside cities.
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Geographic variation in the outcome of interspecific interactions may influence not only the evolutionary trajectories of species but also the structure of local communities. We investigated this community consequence of geographic variation for a facultative mutualism between ants and wild cotton (Gossypium thurberi). Ants consume wild cotton extrafloral nectar and can protect plants from herbivores. We chose three sites that differed in interaction outcome, including a mutualism (ants provided the greatest benefits to plant fitness and responded to manipulations of extrafloral nectar), a potential commensalism (ants increased plant fitness but were unresponsive to extrafloral nectar), and a neutral interaction (ants neither affected plant fitness nor responded to extrafloral nectar). At all sites, we manipulated ants and extrafloral nectar in a factorial design and monitored the abundance, diversity, and composition of other arthropods occurring on wild cotton plants. We predicted that the effects of ants and extrafloral nectar on arthropods would be largest in the location with the mutualism and weakest where the interaction was neutral. A non-metric multidimensional scaling analysis revealed that the presence of ants altered arthropod composition, but only at the two sites in which ants increased plant fitness. At the site with the mutualism, ants also suppressed detritivore/scavenger abundance and increased aphids. The presence of extrafloral nectar increased arthropod abundance where mutual benefits were the strongest, whereas both arthropod abundance and morphospecies richness declined with extrafloral nectar availability at the site with the weakest ant-plant interaction. Some responses were geographically invariable: total arthropod richness and evenness declined by approximately 20% on plants with ants, and extrafloral nectar reduced carnivore abundance when ants were excluded from plants. These results demonstrate that a facultative ant-plant mutualism can alter the composition of arthropod assemblages on plants and that these community-level consequences vary across the landscape.
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Formigas , Biodiversidade , Gossypium , Simbiose , Animais , Arizona , Geografia , Néctar de PlantasRESUMO
OBJECTIVE: To determine the prevalence of work-related psychological distress in staff working in UK paediatric intensive care units (PICU). DESIGN: Online (Qualtrics) staff questionnaire, conducted April to May 2018. SETTING: Staff working in 29 PICUs and 10 PICU transport services were invited to participate. PARTICIPANTS: 1656 staff completed the survey: 1194 nurses, 270 physicians and 192 others. 234 (14%) respondents were male. Median age was 35 (IQR 28-44). MAIN OUTCOME MEASURES: The Moral Distress Scale-Revised (MDS-R) was used to look at moral distress, the abbreviated Maslach Burnout Inventory to examine the depersonalisation and emotional exhaustion domains of burnout, and the Trauma Screening Questionnaire (TSQ) to assess risk of post-traumatic stress disorder (PTSD). RESULTS: 435/1194 (36%) nurses, 48/270 (18%) physicians and 19/192 (10%) other staff scored above the study threshold for moral distress (≥90 on MDS-R) (χ2 test, p<0.00001). 594/1194 (50%) nurses, 99/270 (37%) physicians and 86/192 (45%) other staff had high burnout scores (χ2 test, p=0.0004). 366/1194 (31%) nurses, 42/270 (16%) physicians and 21/192 (11%) other staff scored at risk for PTSD (χ2 test, p<0.00001). Junior nurses were at highest risk of moral distress and PTSD, and junior doctors of burnout. Larger unit size was associated with higher MDS-R, burnout and TSQ scores. CONCLUSIONS: These results suggest that UK PICU staff are experiencing work-related distress. Further studies are needed to understand causation and to develop strategies for prevention and treatment.
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Unidades de Terapia Intensiva Pediátrica , Estresse Ocupacional/epidemiologia , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Reino UnidoRESUMO
Many symbionts supplement their host's diet with essential nutrients. However, whether these nutrients also enhance parasitism is unknown. In this study, we investigated whether folate (vitamin B9) production by the tsetse fly (Glossina spp.) essential mutualist, Wigglesworthia, aids auxotrophic African trypanosomes in completing their life cycle within this obligate vector. We show that the expression of Wigglesworthia folate biosynthesis genes changes with the progression of trypanosome infection within tsetse. The disruption of Wigglesworthia folate production caused a reduction in the percentage of flies that housed midgut (MG) trypanosome infections. However, decreased folate did not prevent MG trypanosomes from migrating to and establishing an infection in the fly's salivary glands, thus suggesting that nutrient requirements vary throughout the trypanosome life cycle. We further substantiated that trypanosomes rely on symbiont-generated folate by feeding this vitamin to Glossina brevipalpis, which exhibits low trypanosome vector competency and houses Wigglesworthia incapable of producing folate. Folate-supplemented G. brevipalpis flies were significantly more susceptible to trypanosome infection, further demonstrating that this vitamin facilitates parasite infection establishment. Our cumulative results provide evidence that Wigglesworthia provides a key metabolite (folate) that is "hijacked" by trypanosomes to enhance their infectivity, thus indirectly impacting tsetse species vector competency. Parasite dependence on symbiont-derived micronutrients, which likely also occurs in other arthropod vectors, represents a relationship that may be exploited to reduce disease transmission.IMPORTANCE Parasites elicit several physiological changes in their host to enhance transmission. Little is known about the functional association between parasitism and microbiota-provisioned resources typically dedicated to animal hosts and how these goods may be rerouted to optimize parasite development. This study is the first to identify a specific symbiont-generated metabolite that impacts insect vector competence by facilitating parasite establishment and, thus, eventual transmission. Specifically, we demonstrate that the tsetse fly obligate mutualist Wigglesworthia provisions folate (vitamin B9) that pathogenic African trypanosomes exploit in an effort to successfully establish an infection in the vector's MG. This process is essential for the parasite to complete its life cycle and be transmitted to a new vertebrate host. Disrupting metabolic contributions provided by the microbiota of arthropod disease vectors may fuel future innovative control strategies while also offering minimal nontarget effects.
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Ácido Fólico/biossíntese , Simbiose , Trypanosoma/fisiologia , Moscas Tsé-Tsé/microbiologia , Moscas Tsé-Tsé/parasitologia , Wigglesworthia/metabolismo , Animais , Vias Biossintéticas , Feminino , Trato Gastrointestinal/parasitologia , Interações Hospedeiro-Parasita , MasculinoRESUMO
Lectins comprise a family of related proteins that mediate essential cell functions through binding to carbohydrates. Within this protein family, C-type lectins are defined by the requirement of calcium for optimal biologic activity. Using reverse transcription PCR, a cDNA corresponding to a putative C-type lectin has been amplified from the hookworm parasite Ancylostoma ceylanicum. The 550 nucleotide open reading frame of the A. ceylanicum C-type Lectin-1 (AceCTL-1) cDNA corresponds to a 167 amino acid mature protein (18,706 Da) preceded by a 17 amino acid secretory signal sequence. The recombinant protein (rAceCTL-1) was expressed in Drosophila S2 cells and purified using a combination of affinity chromatography and reverse phase HPLC. Using in vitro carbohydrate binding studies, it was determined that rAceCTL-1 binds N-acetyl-d-glucosamine, a common component of eukaryotic egg cell membranes. Using a polyclonal IgG raised against the recombinant protein, the native AceCTL-1 was identified in sperm and soluble protein extracts of adult male A. ceylanicum by immunoblot. Probing of adult hookworm sections with the polyclonal IgG demonstrated localization to the testes in males, as well as the spermatheca and developing embryos in females, consistent with its role as a sperm protein. Together, these data strongly suggest that AceCTL-1 is a male gender-specific C-type lectin with a function in hookworm reproductive physiology.
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Ancylostoma/química , Ancilostomíase/parasitologia , Clonagem Molecular , Proteínas de Helminto/fisiologia , Lectinas Tipo C/fisiologia , Sequência de Aminoácidos , Ancylostoma/genética , Ancylostoma/fisiologia , Animais , Cricetinae , DNA Complementar , Feminino , Proteínas de Helminto/química , Proteínas de Helminto/genética , Lectinas Tipo C/química , Lectinas Tipo C/genética , Masculino , Mesocricetus , Dados de Sequência Molecular , Fases de Leitura Aberta , Reprodução , Alinhamento de SequênciaRESUMO
We determined prevalence and altitudinal distribution of introduced avian malarial infections (Plasmodium relictum) and pox-like lesions (Avipoxvirus) in forest birds from Kipahulu Valley, Haleakala National Park, on the island of Maui, and we identified primary larval habitat for the mosquito vector of this disease. This intensively managed wilderness area and scientific reserve is one of the most pristine areas of native forest remaining in the state of Hawai'i, and it will become increasingly important as a site for restoration and recovery of endangered forest birds. Overall prevalence of malarial infections in the valley was 8% (11/133) in native species and 4% (4/101) in nonnative passerines; prevalence was lower than reported for comparable elevations and habitats elsewhere in the state. Infections occurred primarily in 'Apapane (Himatione sanguinea) and Hawai'i 'Amakihi (Hemignathus virens) at elevations below 1,400 m. Pox-like lesions were detected in only two Hawai'i 'Amakihi (2%; 2/94) at elevations below 950 m. We did not detect malaria or pox in birds caught at 1,400 m in upper reaches of the valley. Adult mosquitoes (Culex quinquefasciatus) were captured at four sites at elevations of 640, 760, 915, and 975 m, respectively. Culex quinquefasciatus larvae were found only in rock holes along intermittent tributaries of the two largest streams in the valley, but not in standing surface water, pig wallows, ground pools, tree cavities, and tree fern cavities. Mosquito populations in the valley are low, and they are probably influenced by periods of high rainfall that flush stream systems.
Assuntos
Avipoxvirus , Doenças das Aves/epidemiologia , Conservação dos Recursos Naturais , Malária Aviária/epidemiologia , Infecções por Poxviridae/veterinária , Altitude , Animais , Animais Selvagens/parasitologia , Animais Selvagens/virologia , Doenças das Aves/patologia , Aves , Culex/parasitologia , Culex/virologia , Reservatórios de Doenças/veterinária , Havaí/epidemiologia , Insetos Vetores/parasitologia , Insetos Vetores/virologia , Malária Aviária/patologia , Passeriformes/virologia , Infecções por Poxviridae/epidemiologia , Infecções por Poxviridae/patologia , Prevalência , Estações do AnoRESUMO
BACKGROUND AND OBJECTIVES: Adolescence is a critical life-stage that sets the foundation for health in adulthood. Adolescent women are a unique population and should be targeted as such for nutrition promotion activities. Using Indonesia as a case study, this qualitative study aimed to identify existing nutrition promotion programs aimed at adolescent girls, how best to target this population and effective recommendations to inform nutrition education program design for this important group. METHODS AND STUDY DESIGN: Semi-structured interviews and questionnaires were conducted with ten key informants working in public health in Indonesia. Interview transcripts were analysed and coded to identify key themes. RESULTS: No existing nutrition education programs targeting adolescent women in Indonesia were identified. Several strategies apply to nutrition programs for adolescent girls: 1) nutrition promotion messages that are relevant to the lifestyles and interests of adolescent women; 2) technology-based interventions show promise, however, they need to be appropriately targeted to sub-groups; 3) school remains an important setting; and 4) early marriage is an important issue affecting nutritional status and engagement of adolescent girls. The informants recommended that: 1) more research is needed about the underlying motivations for behaviour change among adolescent women and ways to effectively implement the identified engagement strategies; 2) adolescent girls should be included in program design to improve its suitability and uptake; and 3) government budget and policy support is crucial to success. CONCLUSIONS: Adolescent women are an important population group and more research is required to identify the optimal forms of engagement to improve nutrition programs for them.