767 research outputs found
'Leaves and Eats Shoots': Direct Terrestrial Feeding Can Supplement Invasive Red Swamp Crayfish in Times of Need
PMCID: PMC3411828This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Waves of Invaders: Interactions among Invasive Species and their Impacts on Ecosystem Structure and Functioning
PhDMany freshwater ecosystems sustain several invasive species. Here I examine multiple invasions in two highly invaded and well catalogued catchments; Lake Naivasha, Kenya and River Thames, England. New metrics, derived from stable isotope analysis, are used to provide measures of trophic diversity and to examine dietary interactions among species. I test the hypothesis that functionally similar sympatric species will occupy a smaller niche than their allopatric counterparts. Additionally, I quantify the impact of multiple invasive species on ecosystem structure and functioning in order to address the question; do interactions among species amplify or mitigate one another’s impact?
In Lake Naivasha, the stable isotope metrics revealed serial replacement of invasive species due to dietary interactions. Invasive red swamp crayfish were eventually excluded from the lake due to niche restriction in the presence of a more recent invader, the common carp. Now, the crayfish have migrated into the catchment where they overlap with a species of native river crab. Here, I found a novel mechanism of invasion, whereby the crayfish restricted their niche at the invasion front in order to reduce competition with crabs. Crayfish also caused significant changes in invertebrate community structure and increased decomposition rates, which indirectly resulted in displacement of the crabs.
In the Thames catchment, I catalogue the non-indigenous species and show how invasion rates have increased significantly since 1800 due to globalisation. Using the four species of invasive crayfish present (red swamp, signal, Turkish and virile), I demonstrate their extensive diet plasticity using novel measures of niche width and individual specialisation based on stable isotope data. Interactions among the crayfish were examined and this revealed that each species has varying and independent impacts on invertebrate community structure, algal standing stock and decomposition rates. Hence, interactions among invaders are not expected to amplify or mitigate one another’s impact and instead, the combined impact will be the sum of their allopatric impacts.School of Biological and Chemical Sciences at Queen Mary and the UK Environment Agenc
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Basal rot of narcissus : understanding pathogenicity in fusarium oxysporum f. sp. narcissi
Fusarium oxysporum is a globally distributed soilborne fungal pathogen causing root rots, bulb rots, crown rots and vascular wilts on a range of horticultural plants. Pathogenic F. oxysporum isolates are highly host specific and are classified as formae speciales. Narcissus is an important ornamental crop and both the quality and yield of flowers and bulbs can be severely affected by a basal rot caused by F. oxysporum f. sp. narcissi (FON); 154 Fusarium isolates were obtained from different locations and Narcissus cultivars in the United Kingdom, representing a valuable resource. A subset of 30 F. oxysporum isolates were all found to be pathogenic and were therefore identified as FON. Molecular characterisation of isolates through sequencing of three housekeeping genes, suggested a monophyletic origin with little divergence. PCR detection of 14 Secreted in Xylem (SIX) genes, previously shown to be associated with pathogenicity in other F. oxysporum f. spp., revealed different complements of SIX7, SIX9, SIX10, SIX12 and SIX13 within FON isolates which may suggest a race structure. SIX gene sequences were unique to FON and SIX10 was present in all isolates, allowing for molecular identification of FON for the first time. The genome of a highly pathogenic isolate was sequenced and lineage specific (LS) regions identified which harboured putative effectors including the SIX genes. Real-time RT-PCR, showed that SIX genes and selected putative effectors were expressed in planta with many significantly upregulated during infection. This is the first study to characterise molecular variation in FON and provide an analysis of the FON genome. Identification of expressed genes potentially associated with virulence provides the basis for future functional studies and new targets for molecular diagnostics
What does the future look like for kelp when facing multiple stressors?
As primary producers and ecosystem engineers, kelp (generally Order Laminariales) are ecologically important, and their decline could have far-reaching consequences. Kelp are valuable in forming habitats for fish and invertebrates and are crucial for adaptation to climate change by creating coastal defenses and in providing key functions, such as carbon sequestration and food provision. Kelp are threatened by multiple stressors, such as climate change, over-harvesting of predators, and pollution. In this opinion paper, we discuss how these stressors may interact to affect kelp, and how this varies under different contexts. We argue that more research that bridges kelp conservation and multiple stressor theory is needed and outline key questions that should be addressed as a priority. For instance, it is important to understand how previous exposure (either to earlier generations or life stages) determines responses to emerging stressors, and how responses in kelp scale up to alter food webs and ecosystem functioning. By increasing the temporal and biological complexity of kelp research in this way, we will improve our understanding allowing better predictions. This research is essential for the effective conservation and potential restoration of kelp in our rapidly changing world
Vector competence of Aedes aegypti, Culex tarsalis, and Culex quinquefasciatus from California for Zika virus.
Zika virus (ZIKV) has emerged since 2013 as a significant global human health threat following outbreaks in the Pacific Islands and rapid spread throughout South and Central America. Severe congenital and neurological sequelae have been linked to ZIKV infections. Assessing the ability of common mosquito species to transmit ZIKV and characterizing variation in mosquito transmission of different ZIKV strains is important for estimating regional outbreak potential and for prioritizing local mosquito control strategies for Aedes and Culex species. In this study, we evaluated the laboratory vector competence of Aedes aegypti, Culex quinquefasciatus, and Culex tarsalis that originated in areas of California where ZIKV cases in travelers since 2015 were frequent. We compared infection, dissemination, and transmission rates by measuring ZIKV RNA levels in cohorts of mosquitoes that ingested blood meals from type I interferon-deficient mice infected with either a Puerto Rican ZIKV strain from 2015 (PR15), a Brazilian ZIKV strain from 2015 (BR15), or an ancestral Asian-lineage Malaysian ZIKV strain from 1966 (MA66). With PR15, Cx. quinquefasciatus was refractory to infection (0%, N = 42) and Cx. tarsalis was infected at 4% (N = 46). No ZIKV RNA was detected in saliva from either Culex species 14 or 21 days post feeding (dpf). In contrast, Ae. aegypti developed infection rates of 85% (PR15; N = 46), 90% (BR15; N = 20), and 81% (MA66; N = 85) 14 or 15 dpf. Although MA66-infected Ae. aegypti showed higher levels of ZIKV RNA in mosquito bodies and legs, transmission rates were not significantly different across virus strains (P = 0.13, Fisher's exact test). To confirm infectivity and measure the transmitted ZIKV dose, we enumerated infectious ZIKV in Ae. aegypti saliva using Vero cell plaque assays. The expectorated plaque forming units PFU varied by viral strain: MA66-infected expectorated 13±4 PFU (mean±SE, N = 13) compared to 29±6 PFU for PR15-infected (N = 13) and 35±8 PFU for BR15-infected (N = 6; ANOVA, df = 2, F = 3.8, P = 0.035). These laboratory vector competence results support an emerging consensus that Cx. tarsalis and Cx. quinquefasciatus are not vectors of ZIKV. These results also indicate that Ae. aegypti from California are efficient laboratory vectors of ancestral and contemporary Asian lineage ZIKV
Prevalence and Characterization of Avoidant Restrictive Food Intake Disorder in a Paediatric Population
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Draft genome sequence of an onion basal rot isolate of Fusarium proliferatum
Fusarium proliferatum is a component of the onion basal rot disease complex. We present an annotated F. proliferatum draft genome sequence, totaling 45.8 Mb in size, assembled into 597 contigs, with a predicted 15,418 genes. The genome contains 58 secondary metabolite clusters and homologs of the Fusarium oxysporum effector SIX2
Providing men at risk of suicide with emotional support and advice with employment, housing and financial difficulties:A qualitative evaluation of the Hope service
Galectin-3 identifies a subset of macrophages with a potential beneficial role in atherosclerosis:Macrophage galectin-3 prevents plaque progression
Toward an Equity-Driven Conceptual Model of COVID-19 Vaccine Decision-Making for People with IDD
COVID-19 presented a public health emergency in the U.S., resulting in severe illness, hospitalizations, high mortality rates, and long-term adverse health care conditions. Several studies examined the disparities in transmission rates, barriers to care, and negative health outcomes for persons with disabilities, particularly people with intellectual and developmental disabilities (I/DD). While data revealed similar trends among Black, Hispanic or Latino/a/x/e, Native, Indigenous, and Asian people, outcomes are compounded for people of color with I/DD. Several historical, pervasive, systemic, structural, and attitudinal barriers have constrained healthcare access and adequate treatment, instigating feelings of distrust among those in systems of care. Although vaccination is effective in minimizing adverse outcomes, COVID-19 vaccine policies and rollouts have also followed inequitable patterns in distribution and accessibility. To better address the concerns and needs of communities, a multidisciplinary team at a University Center of Excellence in Developmental Disabilities (UCEDD) engaged in a generative, multistep, systematic process to explore factors that influence vaccine confidence among people with I/DD, their families, and support circles, particularly people of color with IDD. Garnering data and input from multiple sources, we uncovered several complexities around vaccination, which include (a) accessibility; (b) context, history, and sociocultural concerns; (c) policies; (d) communication and media; and (e) a continuum of vaccine confidence and supported decision-making. Findings from these efforts underscore the centrality of equity and trust, with implications for practitioners, institutions, policymakers, and public health strategists. Furthermore, our model can serve as a useful framework for people invested in promoting healthcare equity in vaccination for people with I/DD and with multiple marginalized identities
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