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1.
Clin Transplant ; 38(2): e15249, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38369810

RESUMO

BACKGROUND: Desensitization is one of the strategies to reduce antibodies and facilitate heart transplantation in highly sensitized patients. We describe our center's desensitization experience with combination of plasma cell (PC) depletion therapy (with proteasome inhibitor or daratumumab) and costimulation blockade (with belatacept). METHODS: We reviewed five highly sensitized patients who underwent desensitization therapy with plasma cell depletion and costimulation blockade. We evaluated the response to therapy by measuring the changes in cPRA, average MFI, and number of positive beads > 5000MFI. RESULTS: Five patients, mean age of 56 (37-66) years with average cPRA of 98% at 5000 MFI underwent desensitization therapy. After desensitization, mean cPRA decreased from 98% to 70% (p = .09), average number of beads > 5000 MFI decreased from 59 to 37 (p = .15), and average MFI of beads > 5000 MFI decreased from 16713 to 13074 (p = .26). CONCLUSION: Combined PC depletion and CoB could be a reasonable strategy for sustained reduction in antibodies in highly sensitized patients being listed for heart transplantation.


Assuntos
Transplante de Coração , Plasmócitos , Humanos , Pessoa de Meia-Idade , Abatacepte/uso terapêutico , Abatacepte/farmacologia , Dessensibilização Imunológica , Rejeição de Enxerto/etiologia , Rejeição de Enxerto/prevenção & controle , Antígenos HLA , Isoanticorpos , Inibidores de Proteassoma , Adulto , Idoso
2.
Glob Chang Biol ; 28(8): 2555-2577, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34951743

RESUMO

A multitude of actions to protect, sustainably manage and restore natural and modified ecosystems can have co-benefits for both climate mitigation and biodiversity conservation. Reducing greenhouse emissions to limit warming to less than 1.5 or 2°C above preindustrial levels, as outlined in the Paris Agreement, can yield strong co-benefits for land, freshwater and marine biodiversity and reduce amplifying climate feedbacks from ecosystem changes. Not all climate mitigation strategies are equally effective at producing biodiversity co-benefits, some in fact are counterproductive. Moreover, social implications are often overlooked within the climate-biodiversity nexus. Protecting biodiverse and carbon-rich natural environments, ecological restoration of potentially biodiverse and carbon-rich habitats, the deliberate creation of novel habitats, taking into consideration a locally adapted and meaningful (i.e. full consequences considered) mix of these measures, can result in the most robust win-win solutions. These can be further enhanced by avoidance of narrow goals, taking long-term views and minimizing further losses of intact ecosystems. In this review paper, we first discuss various climate mitigation actions that evidence demonstrates can negatively impact biodiversity, resulting in unseen and unintended negative consequences. We then examine climate mitigation actions that co-deliver biodiversity and societal benefits. We give examples of these win-win solutions, categorized as 'protect, restore, manage and create', in different regions of the world that could be expanded, upscaled and used for further innovation.


Assuntos
Mudança Climática , Ecossistema , Biodiversidade , Carbono , Clima , Conservação dos Recursos Naturais/métodos
3.
Glob Chang Biol ; 28(9): 2846-2874, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35098619

RESUMO

The two most urgent and interlinked environmental challenges humanity faces are climate change and biodiversity loss. We are entering a pivotal decade for both the international biodiversity and climate change agendas with the sharpening of ambitious strategies and targets by the Convention on Biological Diversity and the United Nations Framework Convention on Climate Change. Within their respective Conventions, the biodiversity and climate interlinked challenges have largely been addressed separately. There is evidence that conservation actions that halt, slow or reverse biodiversity loss can simultaneously slow anthropogenic mediated climate change significantly. This review highlights conservation actions which have the largest potential for mitigation of climate change. We note that conservation actions have mainly synergistic benefits and few antagonistic trade-offs with climate change mitigation. Specifically, we identify direct co-benefits in 14 out of the 21 action targets of the draft post-2020 global biodiversity framework of the Convention on Biological Diversity, notwithstanding the many indirect links that can also support both biodiversity conservation and climate change mitigation. These relationships are context and scale-dependent; therefore, we showcase examples of local biodiversity conservation actions that can be incentivized, guided and prioritized by global objectives and targets. The close interlinkages between biodiversity, climate change mitigation, other nature's contributions to people and good quality of life are seldom as integrated as they should be in management and policy. This review aims to re-emphasize the vital relationships between biodiversity conservation actions and climate change mitigation in a timely manner, in support to major Conferences of Parties that are about to negotiate strategic frameworks and international goals for the decades to come.


Assuntos
Conservação dos Recursos Naturais , Qualidade de Vida , Biodiversidade , Mudança Climática , Ecossistema , Humanos
4.
Lancet ; 395(10231): 1217-1224, 2020 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-32203691

RESUMO

BACKGROUND: Benzodiazepine-refractory, or established, status epilepticus is thought to be of similar pathophysiology in children and adults, but differences in underlying aetiology and pharmacodynamics might differentially affect response to therapy. In the Established Status Epilepticus Treatment Trial (ESETT) we compared the efficacy and safety of levetiracetam, fosphenytoin, and valproate in established status epilepticus, and here we describe our results after extending enrolment in children to compare outcomes in three age groups. METHODS: In this multicentre, double-blind, response-adaptive, randomised controlled trial, we recruited patients from 58 hospital emergency departments across the USA. Patients were eligible for inclusion if they were aged 2 years or older, had been treated for a generalised convulsive seizure of longer than 5 min duration with adequate doses of benzodiazepines, and continued to have persistent or recurrent convulsions in the emergency department for at least 5 min and no more than 30 min after the last dose of benzodiazepine. Patients were randomly assigned in a response-adaptive manner, using Bayesian methods and stratified by age group (<18 years, 18-65 years, and >65 years), to levetiracetam, fosphenytoin, or valproate. All patients, investigators, study staff, and pharmacists were masked to treatment allocation. The primary outcome was absence of clinically apparent seizures with improved consciousness and without additional antiseizure medication at 1 h from start of drug infusion. The primary safety outcome was life-threatening hypotension or cardiac arrhythmia. The efficacy and safety outcomes were analysed by intention to treat. This study is registered in ClinicalTrials.gov, NCT01960075. FINDINGS: Between Nov 3, 2015, and Dec 29, 2018, we enrolled 478 patients and 462 unique patients were included: 225 children (aged <18 years), 186 adults (18-65 years), and 51 older adults (>65 years). 175 (38%) patients were randomly assigned to levetiracetam, 142 (31%) to fosphenyltoin, and 145 (31%) were to valproate. Baseline characteristics were balanced across treatments within age groups. The primary efficacy outcome was met in those treated with levetiracetam for 52% (95% credible interval 41-62) of children, 44% (33-55) of adults, and 37% (19-59) of older adults; with fosphenytoin in 49% (38-61) of children, 46% (34-59) of adults, and 35% (17-59) of older adults; and with valproate in 52% (41-63) of children, 46% (34-58) of adults, and 47% (25-70) of older adults. No differences were detected in efficacy or primary safety outcome by drug within each age group. With the exception of endotracheal intubation in children, secondary safety outcomes did not significantly differ by drug within each age group. INTERPRETATION: Children, adults, and older adults with established status epilepticus respond similarly to levetiracetam, fosphenytoin, and valproate, with treatment success in approximately half of patients. Any of the three drugs can be considered as a potential first-choice, second-line drug for benzodiazepine-refractory status epilepticus. FUNDING: National Institute of Neurological Disorders and Stroke, National Institutes of Health.


Assuntos
Anticonvulsivantes/administração & dosagem , Levetiracetam/administração & dosagem , Fenitoína/análogos & derivados , Estado Epiléptico/tratamento farmacológico , Ácido Valproico/administração & dosagem , Adolescente , Adulto , Distribuição por Idade , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Anticonvulsivantes/efeitos adversos , Criança , Pré-Escolar , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Lactente , Levetiracetam/efeitos adversos , Masculino , Pessoa de Meia-Idade , Fenitoína/administração & dosagem , Fenitoína/efeitos adversos , Ácido Valproico/efeitos adversos , Adulto Jovem
5.
Conserv Biol ; 34(1): 113-124, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31454857

RESUMO

A key obstacle to conservation success is the tendency of conservation professionals to tackle each challenge individually rather than collectively and in context. We sought to prioritize barriers to conservation previously described in the conservation literature. We undertook an online survey of 154 practitioners from over 70 countries to ascertain the most important barriers to conservation they faced. We used statistical analyses to identify the key impediments to conservation success and to examine whether these were affected by organizational attributes. Twenty-one barriers were identified. The importance ascribed to those was influenced by continent of operation and organization size, but not by organization age or autonomy (from larger parent organizations). We found the most important barriers to consider when undertaking conservation action were wider issues (e.g., population growth, consumerism, favoring development, and industrial-scale activity), operating environment (e.g., lack of political will, ineffective law enforcement, weak governments, corruption, safety and security), community attributes (e.g., dynamics, conflicts, and education levels), and the way conservation is undertaken (overconfidence, lack of funding, and externally set agendas). However, we advise against applying a one-size-fits-all approach. We propose that conservationists account for the complex socioecological systems they operate in if they are to achieve success.


Percepciones de los Profesionales Como Medio para Establecer un Contexto Para la Conservación Resumen Un obstáculo clave para el éxito de la conservación es la tendencia de los profesionales de la conservación a abordar cada desafío individualmente en lugar de colectivamente y en contexto. Buscamos priorizar las barreras a la conservación descritas anteriormente en la literatura de conservación. Realizamos una encuesta en línea a 154 profesionales de más de 70 países para determinar las barreras más importantes para la conservación a las que se enfrentaban. Utilizamos análisis estadísticos para identificar los principales impedimentos para el éxito de la conservación y para examinar si estos se vieron afectados por atributos organizativos. Se identificaron veintiún barreras. La importancia que se les atribuye fue influenciada por el continente donde operan y el tamaño de la organización, pero no por la edad o la autonomía de la organización (de las organizaciones más grandes). Encontramos que los obstáculos más importantes a tener en cuenta al emprender acciones de conservación eran cuestiones más amplias (e. g., crecimiento de la población, consumismo, fomento del desarrollo y actividad a escala industrial), medio ambiente (e. g., falta de voluntad política, ineficacia en la aplicación de la ley, gobiernos débiles, corrupción, seguridad y protección), atributos comunitarios (e. g., dinámicas, conflictos y niveles educativos) y la forma en que se lleva a cabo la conservación (exceso de confianza, falta de financiamiento y agendas establecidas externamente). Sin embargo, aconsejamos no aplicar un enfoque "un tamaño se ajusta a todo". Para lograr el éxito, proponemos que los conservacionistas tengan en cuenta los complejos sistemas socioecológicos en los que operan.


Assuntos
Conservação dos Recursos Naturais
6.
Sensors (Basel) ; 19(3)2019 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-30699950

RESUMO

Conservation researchers require low-cost access to acoustic monitoring technology. However, affordable tools are often constrained to short-term studies due to high energy consumption and limited storage. To enable long-term monitoring, energy and space efficiency must be improved on such tools. This paper describes the development and deployment of three acoustic detection algorithms that reduce the power and storage requirements of acoustic monitoring on affordable, open-source hardware. The algorithms aim to detect bat echolocation, to search for evidence of an endangered cicada species, and also to collect evidence of poaching in a protected nature reserve. The algorithms are designed to run on AudioMoth: a low-cost, open-source acoustic monitoring device, developed by the authors and widely adopted by the conservation community. Each algorithm addresses a detection task of increasing complexity, implementing extra analytical steps to account for environmental conditions such as wind, analysing samples multiple times to prevent missed events, and incorporating a hidden Markov model for sample classification in both the time and frequency domain. For each algorithm, we report on real-world deployments carried out with partner organisations and also benchmark the hidden Markov model against a convolutional neural network, a deep-learning technique commonly used for acoustics. The deployments demonstrate how acoustic detection algorithms extend the use of low-cost, open-source hardware and facilitate a new avenue for conservation researchers to perform large-scale monitoring.

7.
Proc Biol Sci ; 285(1884)2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30068675

RESUMO

An understanding of the balance of interspecific competition and the physical environment in structuring organismal communities is crucial because those communities structured primarily by their physical environment typically exhibit greater sensitivity to environmental change than those structured predominantly by competitive interactions. Here, using detailed phylogenetic and functional information, we investigate this question in macrofaunal assemblages from Northwest Atlantic Ocean continental slopes, a high seas region projected to experience substantial environmental change through the current century. We demonstrate assemblages to be both phylogenetically and functionally under-dispersed, and thus conclude that the physical environment, not competition, may dominate in structuring deep-ocean communities. Further, we find temperature and bottom trawling intensity to be among the environmental factors significantly related to assemblage diversity. These results hint that deep-ocean communities are highly sensitive to their physical environment and vulnerable to environmental perturbation, including by direct disturbance through fishing, and indirectly through the changes brought about by climate change.


Assuntos
Organismos Aquáticos , Ecossistema , Pesqueiros , Animais , Oceano Atlântico , Mudança Climática , Filogenia , Temperatura
8.
Mol Ecol ; 27(23): 4680-4697, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30308702

RESUMO

The mechanisms that determine patterns of species dispersal are important factors in the production and maintenance of biodiversity. Understanding these mechanisms helps to forecast the responses of species to environmental change. Here, we used a comparative framework and genomewide data obtained through RAD-Seq to compare the patterns of connectivity among breeding colonies for five penguin species with shared ancestry, overlapping distributions and differing ecological niches, allowing an examination of the intrinsic and extrinsic barriers governing dispersal patterns. Our findings show that at-sea range and oceanography underlie patterns of dispersal in these penguins. The pelagic niche of emperor (Aptenodytes forsteri), king (A. patagonicus), Adélie (Pygoscelis adeliae) and chinstrap (P. antarctica) penguins facilitates gene flow over thousands of kilometres. In contrast, the coastal niche of gentoo penguins (P. papua) limits dispersal, resulting in population divergences. Oceanographic fronts also act as dispersal barriers to some extent. We recommend that forecasts of extinction risk incorporate dispersal and that management units are defined by at-sea range and oceanography in species lacking genetic data.


Assuntos
Distribuição Animal , Genética Populacional , Genômica , Spheniscidae/genética , Animais , Regiões Antárticas , Ecossistema , Fluxo Gênico , Variação Genética , Técnicas de Genotipagem , Filogenia , Polimorfismo de Nucleotídeo Único , Spheniscidae/classificação
9.
Adv Mar Biol ; 79: 137-224, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30012275

RESUMO

Seamounts are one of the major biomes of the global ocean. The last 25 years of research has seen considerable advances in the understanding of these ecosystems. The interactions between seamounts and steady and variable flows have now been characterised providing a better mechanistic understanding of processes influencing biology. Processes leading to upwelling, including Taylor column formation and tidal rectification, have now been defined as well as those leading to draw down of organic matter from the ocean surface to seamount summit and flanks. There is also an improved understanding of the interactions between seamounts, zooplankton and micronekton communities especially with respect to increased predation pressure in the vicinity of seamounts. Evidence has accumulated of the role of seamounts as hot spots for ocean predators including large pelagic fish, sharks, pinnipeds, cetaceans and seabirds. The complexity of benthic communities associated with seamounts is high and drivers of biodiversity are now being resolved. Claims of high endemism resulting from isolation of seamounts as islands of habitat and speciation have not been supported. However, for species characterised by low dispersal capability, such as some groups of benthic sessile or low-mobility invertebrates, low connectivity between seamount populations has been found with evidence of endemism at a local level. Threats to seamounts have increased in the last 25 years and include overfishing, destructive fishing, marine litter, direct and indirect impacts of climate change and potentially marine mining in the near future. Issues around these threats and their management are discussed.


Assuntos
Ecossistema , Fenômenos Geológicos , Oceanos e Mares , Animais , Conservação dos Recursos Naturais/métodos , Monitoramento Ambiental/métodos
10.
Mol Ecol ; 26(15): 3883-3897, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28488293

RESUMO

Understanding the boundaries of breeding populations is of great importance for conservation efforts and estimates of extinction risk for threatened species. However, determining these boundaries can be difficult when population structure is subtle. Emperor penguins are highly reliant on sea ice, and some populations may be in jeopardy as climate change alters sea-ice extent and quality. An understanding of emperor penguin population structure is therefore urgently needed. Two previous studies have differed in their conclusions, particularly whether the Ross Sea, a major stronghold for the species, is isolated or not. We assessed emperor penguin population structure using 4,596 genome-wide single nucleotide polymorphisms (SNPs), characterized in 110 individuals (10-16 per colony) from eight colonies around Antarctica. In contrast to a previous conclusion that emperor penguins are panmictic around the entire continent, we find that emperor penguins comprise at least four metapopulations, and that the Ross Sea is clearly a distinct metapopulation. Using larger sample sizes and a thorough assessment of the limitations of different analytical methods, we have shown that population structure within emperor penguins does exist and argue that its recognition is vital for the effective conservation of the species. We discuss the many difficulties that molecular ecologists and managers face in the detection and interpretation of subtle population structure using large SNP data sets, and argue that subtle structure should be taken into account when determining management strategies for threatened species, until accurate estimates of demographic connectivity among populations can be made.


Assuntos
Conservação dos Recursos Naturais , Genética Populacional , Spheniscidae/genética , Animais , Regiões Antárticas , Mudança Climática , Camada de Gelo , Polimorfismo de Nucleotídeo Único , Densidade Demográfica
11.
BMC Evol Biol ; 16(1): 211, 2016 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-27733109

RESUMO

BACKGROUND: Seabirds are important components of marine ecosystems, both as predators and as indicators of ecological change, being conspicuous and sensitive to changes in prey abundance. To determine whether fluctuations in population sizes are localised or indicative of large-scale ecosystem change, we must first understand population structure and dispersal. King penguins are long-lived seabirds that occupy a niche across the sub-Antarctic zone close to the Polar Front. Colonies have very different histories of exploitation, population recovery, and expansion. RESULTS: We investigated the genetic population structure and patterns of colonisation of king penguins across their current range using a dataset of 5154 unlinked, high-coverage single nucleotide polymorphisms generated via restriction site associated DNA sequencing (RADSeq). Despite breeding at a small number of discrete, geographically separate sites, we find only very slight genetic differentiation among colonies separated by thousands of kilometers of open-ocean, suggesting migration among islands and archipelagos may be common. Our results show that the South Georgia population is slightly differentiated from all other colonies and suggest that the recently founded Falkland Island colony is likely to have been established by migrants from the distant Crozet Islands rather than nearby colonies on South Georgia, possibly as a result of density-dependent processes. CONCLUSIONS: The observed subtle differentiation among king penguin colonies must be considered in future conservation planning and monitoring of the species, and demographic models that attempt to forecast extinction risk in response to large-scale climate change must take into account migration. It is possible that migration could buffer king penguins against some of the impacts of climate change where colonies appear panmictic, although it is unlikely to protect them completely given the widespread physical changes projected for their Southern Ocean foraging grounds. Overall, large-scale population genetic studies of marine predators across the Southern Ocean are revealing more interconnection and migration than previously supposed.


Assuntos
Migração Animal/fisiologia , Ecossistema , Genética Populacional , Spheniscidae/genética , Animais , Regiões Antárticas , Teorema de Bayes , Análise por Conglomerados , Análise Discriminante , Variação Genética , Técnicas de Genotipagem , Geografia , Filogeografia , Densidade Demográfica , Análise de Componente Principal
12.
Mol Phylogenet Evol ; 84: 185-204, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25481103

RESUMO

Sequence data were obtained for five different loci, both mitochondrial (cox1, mtMutS, 16S) and nuclear (18S, 28S rDNA), from 64 species representing 25 genera of the common deep-sea octocoral family Primnoidae. We tested the hypothesis that Primnoidae have an Antarctic origin, as this is where they currently have high species richness, using Maximum likelihood and Bayesian inference methods of phylogenetic analysis. Using a time-calibrated molecular phylogeny we also investigated the time of species radiation in sub-Antarctic Primnoidae. Our relatively wide taxon sampling and phylogenetic analysis supported Primnoidae as a monophyletic family. The base of the well-supported phylogeny was Pacific in origin, indicating Primnoidae sub-Antarctic diversity is a secondary species radiation. There is also evidence for a subsequent range extension of sub-Antarctic lineages into deep-water areas of the Indian and Pacific Oceans. Conservative and speculative fossil-calibration analyses resulted in two differing estimations of sub-Antarctic species divergence times. Conservative analysis suggested a sub-Antarctic species radiation occurred ∼52MYA (95% HPD: 36-73MYA), potentially before the opening of the Drake Passage and Antarctic Circumpolar Current (ACC) formation (41-37MYA). Speculative analysis pushed this radiation back into the late Jurassic, 157MYA (95% HPD: 118-204MYA). Genus-level groupings were broadly supported in this analysis with some notable polyphyletic exceptions: Callogorgia, Fanellia, Primnoella, Plumarella, Thouarella. Molecular and morphological evidence supports the placement of Tauroprimnoa austasensis within Dasystenella and Fannyella kuekenthali within Metafannyella.


Assuntos
Antozoários/classificação , Evolução Biológica , Filogenia , Animais , Regiões Antárticas , Antozoários/genética , Teorema de Bayes , DNA Mitocondrial/genética , Funções Verossimilhança , Modelos Genéticos , Oceano Pacífico , Análise de Sequência de DNA
13.
Glob Chang Biol ; 21(6): 2215-26, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25728986

RESUMO

The relationship between population structure and demographic history is critical to understanding microevolution and for predicting the resilience of species to environmental change. Using mitochondrial DNA from extant colonies and radiocarbon-dated subfossils, we present the first microevolutionary analysis of emperor penguins (Aptenodytes forsteri) and show their population trends throughout the last glacial maximum (LGM, 19.5-16 kya) and during the subsequent period of warming and sea ice retreat. We found evidence for three mitochondrial clades within emperor penguins, suggesting that they were isolated within three glacial refugia during the LGM. One of these clades has remained largely isolated within the Ross Sea, while the two other clades have intermixed around the coast of Antarctica from Adélie Land to the Weddell Sea. The differentiation of the Ross Sea population has been preserved despite rapid population growth and opportunities for migration. Low effective population sizes during the LGM, followed by a rapid expansion around the beginning of the Holocene, suggest that an optimum set of sea ice conditions exist for emperor penguins, corresponding to available foraging area.


Assuntos
Camada de Gelo , Refúgio de Vida Selvagem , Spheniscidae/genética , Animais , Regiões Antárticas , Evolução Biológica , Mudança Climática , DNA Mitocondrial , Fósseis , Filogeografia , Densidade Demográfica , Spheniscidae/fisiologia
14.
Front Zool ; 12: 13, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26085836

RESUMO

INTRODUCTION: The 'scaly-foot gastropod' (Chrysomallon squamiferum Chen et al., 2015) from deep-sea hydrothermal vent ecosystems of the Indian Ocean is an active mobile gastropod occurring in locally high densities, and it is distinctive for the dermal scales covering the exterior surface of its foot. These iron-sulfide coated sclerites, and its nutritional dependence on endosymbiotic bacteria, are both noted as adaptations to the extreme environment in the flow of hydrogen sulfide. We present evidence for other adaptations of the 'scaly-foot gastropod' to life in an extreme environment, investigated through dissection and 3D tomographic reconstruction of the internal anatomy. RESULTS: Our anatomical investigations of juvenile and adult specimens reveal a large unganglionated nervous system, a simple and reduced digestive system, and that the animal is a simultaneous hermaphrodite. We show that Chrysomallon squamiferum relies on endosymbiotic bacteria throughout post-larval life. Of particular interest is the circulatory system: Chrysomallon has a very large ctenidium supported by extensive blood sinuses filled with haemocoel. The ctenidium provides oxygen for the host but the circulatory system is enlarged beyond the scope of other similar vent gastropods. At the posterior of the ctenidium is a remarkably large and well-developed heart. Based on the volume of the auricle and ventricle, the heart complex represents approximately 4 % of the body volume. This proportionally giant heart primarily sucks blood through the ctenidium and supplies the highly vascularised oesophageal gland. Thus we infer the elaborate cardiovascular system most likely evolved to oxygenate the endosymbionts in an oxygen poor environment and/or to supply hydrogen sulfide to the endosymbionts. CONCLUSIONS: This study exemplifies how understanding the autecology of an organism can be enhanced by detailed investigation of internal anatomy. This gastropod is a large and active species that is abundant in its hydrothermal vent field ecosystem. Yet all of its remarkable features-protective dermal sclerites, circulatory system, high fecundity-can be viewed as adaptations beneficial to its endosymbiont microbes. We interpret these results to show that, as a result of specialisation to resolve energetic needs in an extreme chemosynthetic environment, this dramatic dragon-like species has become a carrying vessel for its bacteria.

15.
PLoS Biol ; 10(1): e1001234, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22235194

RESUMO

Since the first discovery of deep-sea hydrothermal vents along the Galápagos Rift in 1977, numerous vent sites and endemic faunal assemblages have been found along mid-ocean ridges and back-arc basins at low to mid latitudes. These discoveries have suggested the existence of separate biogeographic provinces in the Atlantic and the North West Pacific, the existence of a province including the South West Pacific and Indian Ocean, and a separation of the North East Pacific, North East Pacific Rise, and South East Pacific Rise. The Southern Ocean is known to be a region of high deep-sea species diversity and centre of origin for the global deep-sea fauna. It has also been proposed as a gateway connecting hydrothermal vents in different oceans but is little explored because of extreme conditions. Since 2009 we have explored two segments of the East Scotia Ridge (ESR) in the Southern Ocean using a remotely operated vehicle. In each segment we located deep-sea hydrothermal vents hosting high-temperature black smokers up to 382.8°C and diffuse venting. The chemosynthetic ecosystems hosted by these vents are dominated by a new yeti crab (Kiwa n. sp.), stalked barnacles, limpets, peltospiroid gastropods, anemones, and a predatory sea star. Taxa abundant in vent ecosystems in other oceans, including polychaete worms (Siboglinidae), bathymodiolid mussels, and alvinocaridid shrimps, are absent from the ESR vents. These groups, except the Siboglinidae, possess planktotrophic larvae, rare in Antarctic marine invertebrates, suggesting that the environmental conditions of the Southern Ocean may act as a dispersal filter for vent taxa. Evidence from the distinctive fauna, the unique community structure, and multivariate analyses suggest that the Antarctic vent ecosystems represent a new vent biogeographic province. However, multivariate analyses of species present at the ESR and at other deep-sea hydrothermal vents globally indicate that vent biogeography is more complex than previously recognised.


Assuntos
Biodiversidade , Ecossistema , Fontes Hidrotermais , Água do Mar/química , Animais , Regiões Antárticas , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Crustáceos/classificação , Crustáceos/genética , Crustáceos/crescimento & desenvolvimento , Decápodes/classificação , Decápodes/genética , Decápodes/crescimento & desenvolvimento , Complexo IV da Cadeia de Transporte de Elétrons/genética , Gastrópodes/classificação , Gastrópodes/genética , Gastrópodes/crescimento & desenvolvimento , Geografia , Sulfeto de Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Oceanos e Mares , Filogenia , RNA Ribossômico 16S/genética , RNA Ribossômico 18S/genética , RNA Ribossômico 28S/genética , Água do Mar/microbiologia , Análise de Sequência de DNA , Sódio/metabolismo , Especificidade da Espécie , Temperatura
17.
Adv Mar Biol ; 71: 71-108, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26320616

RESUMO

Body size (weight per individual) is an important concept in ecology. It has been studied in the deep sea where a decrease in size with increasing depth has often been found. This has been explained as an adaptation to food limitation where size reduction results in a lowered metabolic rate and a decreased energetic requirement. However, observations vary, with some studies showing an increase in size with depth, and some finding no depth correlation at all. Here, we collected data from peer-reviewed studies on macro- and meiofaunal abundance and biomass, creating two datasets allowing statistical comparison of factors expected to influence body size in meio- and macrofaunal organisms. Our analyses examined the influence of region, taxonomic group and sampling method on the body size of meiofauna and macrofauna in the deep sea with increasing depth, and the resulting models are presented. At the global scale, meio- and macrofaunal communities show a decrease in body size with increasing depth as expected with the food limitation hypothesis. However, at the regional scale there were differences in trends of body size with depth, either showing a decrease (e.g. southwest Pacific Ocean; meio- and macrofauna) or increase (e.g. Gulf of Mexico; meiofauna only) compared to a global mean. Taxonomic groups also showed differences in body size trends compared to total community average (e.g. Crustacea and Bivalvia). Care must be taken when conducting these studies, as our analyses indicated that sampling method exerts a significant influence on research results. It is possible that differences in physiology, lifestyle and life history characteristics result in different responses to an increase in depth and/or decrease in food availability. This will have implications in the future as food supply to the deep sea changes as a result of climate change (e.g. increased ocean stratification at low to mid latitudes and reduced sea ice duration at high latitudes).


Assuntos
Distribuição Animal/fisiologia , Tamanho Corporal , Ecossistema , Invertebrados/anatomia & histologia , Invertebrados/fisiologia , Animais , Organismos Aquáticos , Biomassa , Invertebrados/classificação
18.
Adv Mar Biol ; 70: 1-286, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26296718

RESUMO

The current hiatus in the establishment of a network of marine protected areas (MPAs) in the Antarctic means that other routes to conservation are required. The protection of overseas territories in the Antarctic and sub-Antarctic represents one way to advance the initiation of such a network. This review of the physical and biological features of the United Kingdom (U.K.) overseas territories of South Georgia and South Sandwich Islands (SGSSI) is undertaken to estimate the importance of the islands in terms of marine conservation in the Southern Ocean and globally. The economy and management of SGSSI are also analysed, and the question of whether the islands already have sufficient protection to constitute part of an Antarctic network of MPAs is assessed. The SGSSI comprise unique geological and physical features, a diverse marine biota, including a significant proportion of endemic species and globally important breeding populations of marine predators. Regardless of past exploitation of biotic resources, such as seals, whales and finfish, SGSSI would make a significant contribution to biological diversity in an Antarctic network of MPAs. At present, conservation measures do not adequately protect all of the biological features that render the islands so important in terms of conservation at a regional and global level. However, a general lack of data on Antarctic marine ecosystems (particularly needed for SGSSSI) makes it difficult to assess this fully. One barrier to achieving more complete protection is the continuing emphasis on fishing effort in these waters by U.K. government. Other non-U.K. Antarctic overseas territories of conservation importance are also compromised as MPAs because of the exploitation of fisheries resources in their waters. The possible non-use values of SGSSI as well as the importance of ecosystem services that are indirectly used by people are outlined in this review. Technology is improving the potential for management of remote MPAs, particularly in the context of incursion by illegal fishing activities and use of satellite surveillance for enforcement of fisheries and conservation regulations. The conflict between commercial exploitation and conservation of Antarctic marine living resources is explored.


Assuntos
Conservação dos Recursos Naturais/legislação & jurisprudência , Ecossistema , Ilhas , Animais , Regiões Antárticas , Caniformia , Comércio , Peixes , Reino Unido , Baleias
19.
bioRxiv ; 2024 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-39229173

RESUMO

An increasing number of treatment failures with current pharmaceutics, as well as a lack of a vaccine, demonstrates the need to develop new treatment options for leishmaniasis. Herein, we describe the synthesis and in vitro analysis of 24 disquaramide compounds targeting the Leishmania major parasite. Of the compounds that were evaluated, six of them ( 13 , 19 , 20 , 22 , 24 , and 26 ) were capable of significantly decreasing the number of parasites by up to 42% compared to the control by day four. This demonstrates that disquaramides either impair parasite replication or have leishmancidal effects. Additionally, none of the disquaramide compounds tested displayed host cell cytotoxicity. These experiments provide evidence that disquaramides have the potential to be effective anti-leishmanial therapeutics.

20.
Mol Phylogenet Evol ; 69(3): 610-8, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23906600

RESUMO

Molecular methods have been used for the first time to determine the phylogeny of families, genera and species within the Pennatulacea (sea pens). Variation in ND2 and mtMutS mitochondrial protein-coding genes proved adequate to resolve phylogenetic relationships among pennatulacean families. The gene mtMutS is more variable than ND2 and differentiates all genera, and many pennatulacean species. A molecular phylogeny based on a Bayesian analysis reveals that suborder Sessiliflorae is paraphyletic and Subselliflorae is polyphyletic. Many families of pennatulaceans do not represent monophyletic groups including Umbellulidae, Pteroeididae, and Kophobelemnidae. The high frequency of morphological homoplasy in pennatulaceans has led to many misinterpretations in the systematics of the group. The traditional classification scheme for pennatulaceans requires revision.


Assuntos
Antozoários/classificação , Evolução Molecular , Filogenia , Animais , Antozoários/genética , Teorema de Bayes , Genes Mitocondriais , Proteínas Mitocondriais/genética , Análise de Sequência de DNA
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