RESUMO
Phase separation of biomolecules into condensates is a key mechanism in the spatiotemporal organization of biochemical processes in cells. However, the impact of the material properties of biomolecular condensates on important processes, such as the control of gene expression, remains largely elusive. Here, the material properties of optogenetically induced transcription factor condensates are systematically tuned, and probed for their impact on the activation of target promoters. It is demonstrated that transcription factors in rather liquid condensates correlate with increased gene expression levels, whereas stiffer transcription factor condensates correlate with the opposite effect, reduced activation of gene expression. The broad nature of these findings is demonstrated in mammalian cells and mice, as well as by using different synthetic and natural transcription factors. These effects are observed for both transgenic and cell-endogenous promoters. The findings provide a novel materials-based layer in the control of gene expression, which opens novel opportunities in optogenetic engineering and synthetic biology.
Assuntos
Fatores de Transcrição , Animais , Camundongos , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Regulação da Expressão Gênica , Optogenética/métodos , Humanos , Regiões Promotoras Genéticas , Condensados Biomoleculares/metabolismoRESUMO
Recovering and distinguishing different ionospheric layers and signals usually requires slow and complicated procedures. In this work, we construct and train five convolutional neural network (CNN) models: DeepLab, fully convolutional DenseNet24 (FC-DenseNet24), deep watershed transform (DWT), Mask R-CNN, and spatial attention-UNet (SA-UNet) for the recovery of ionograms. The performance of the models is evaluated by intersection over union (IoU). We collect and manually label 6131 ionograms, which are acquired from a low-latitude ionosonde in Taiwan. These ionograms are contaminated by strong quasi-static noise, with an average signal-to-noise ratio (SNR) equal to 1.4. Applying the five models to these noisy ionograms, we show that the models can recover useful signals with IoU > 0.6. The highest accuracy is achieved by SA-UNet. For signals with less than 15% of samples in the data set, they can be recovered by Mask R-CNN to some degree (IoU > 0.2). In addition to the number of samples, we identify and examine the effects of three factors: (1) SNR, (2) shape of signal, (3) overlapping of signals on the recovery accuracy of different models. Our results indicate that FC-DenseNet24, DWT, Mask R-CNN and SA-UNet are capable of identifying signals from very noisy ionograms (SNR < 1.4), overlapping signals can be well identified by DWT, Mask R-CNN and SA-UNet, and that more elongated signals are better identified by all models.
Assuntos
Processamento de Imagem Assistida por Computador , Redes Neurais de Computação , Coleta de Dados , Processamento de Imagem Assistida por Computador/métodos , Razão Sinal-Ruído , TaiwanRESUMO
The technique of active ionospheric sounding by ionosondes requires sophisticated methods for the recovery of experimental data on ionograms. In this work, we applied an advanced algorithm of deep learning for the identification and classification of signals from different ionospheric layers. We collected a dataset of 6131 manually labeled ionograms acquired from low-latitude ionosondes in Taiwan. In the ionograms, we distinguished 11 different classes of the signals according to their ionospheric layers. We developed an artificial neural network, FC-DenseNet24, based on the FC-DenseNet convolutional neural network. We also developed a double-filtering algorithm to reduce incorrectly classified signals. That made it possible to successfully recover the sporadic E layer and the F2 layer from highly noise-contaminated ionograms whose mean signal-to-noise ratio was low, SNR = 1.43. The Intersection over Union (IoU) of the recovery of these two signal classes was greater than 0.6, which was higher than the previous models reported. We also identified three factors that can lower the recovery accuracy: (1) smaller statistics of samples; (2) mixing and overlapping of different signals; (3) the compact shape of signals.
Assuntos
Algoritmos , Redes Neurais de Computação , Razão Sinal-Ruído , TaiwanRESUMO
Adult mosquitoes inherit a bacterial community from larvae via transstadial transmission, an understudied process that may influence host-microbe interactions. Microbes contribute to important host life history traits, and analyzing transmitted microbial communities, the interrelationship between larval and adult-associated microbiota, and factors influencing host-microbe relationships provides targets for research. During its larval stage, the yellow fever mosquito (Aedes aegypti) hosts the trichomycete gut fungus Zancudomyces culisetae, and fungal colonization coincides with environmental perturbations in the digestive tract microecosystem. Natural populations are differentially exposed to fungi, thereby potentially harboring distinct microbiota and experiencing disparate host-microbe interactions. This study's objectives were to characterize larval and initial adult microbiomes, investigate variation in diversity and distribution of microbial communities across individuals, and assess whether larval fungal colonization impacted microbiomes at these developmental stages. Laboratory-based fungal infestation assays, sequencing of 16S rRNA gene amplicons, and bacterial load quantification protocols revealed that initial adult microbiomes varied in diversity and distribution. Larval fungal colonization had downstream effects on initial adult microbiomes, significantly reducing microbial community variation, shifting relative abundances of certain bacterial families, and influencing transstadial transmission outcomes of particular genera. Further, abundances of several families consistently decreased in adults relative to levels in larvae, possibly reflecting impacts of host development on specific bacterial taxa. These findings demonstrated that a prolific gut fungus impacted mosquito-associated microbiota at two developmental stages in an insect connected with global human health.IMPORTANCE Mosquitoes are widespread vectors of numerous human pathogens and harbor microbiota known to affect host phenotypic traits. However, little research has directly investigated how bacterial communities associated with larvae and adults are connected. We characterized whole-body bacterial communities in mosquito larvae preceding pupation and in newly emerged adults, and investigated whether a significant biotic factor, fungal colonization of the larval hindgut, impacted these microbiomes. Results showed that fungal colonization reduced microbial community variation across individuals and differentially impacted the outcomes of transstadial transmission for certain bacterial genera, revealing downstream effects of the fungus on initial adult microbiomes. The importance of our research is in providing a thorough comparative analysis of whole-body microbiota harbored in larvae and adults of the yellow fever mosquito (Aedes aegypti) and in demonstrating the important role a widespread gut fungus played in a host-associated microbiome.
Assuntos
Aedes/microbiologia , Aedes/fisiologia , Fungos/fisiologia , Aedes/crescimento & desenvolvimento , Animais , Feminino , Trato Gastrointestinal/microbiologia , Trato Gastrointestinal/fisiologia , Larva/crescimento & desenvolvimento , Larva/microbiologia , Larva/fisiologia , MicrobiotaRESUMO
Smittium (Harpellales, Kickxellomycotina) includes fungal symbionts associated with the digestive tracts of immature aquatic stages of various Diptera, including Chironomidae, Culicidae, Dixidae, Simuliidae, Thaumaleidae, and Tipulidae. With 84 species and the largest collection of cultured strains, Smittium has served as a model to understand the biology of these enigmatic trichomycetes gut fungi, from aspects of biodiversity, evolution, genomics, immunology, and physiology. However, evolutionary histories between Smittium species and their hosts are still not firmly established. Robust phylogenies of both Smittium sensu lato (s.l.) and their lower Diptera hosts have been reconstructed separately, facilitating comparative evolutionary studies between the two. The divergence time of the Smittium s.l. clade was estimated for the first time and compared with the evolutionary history of the insect hosts. The insect gut fungi diversified around 272â¯Ma (204-342â¯Ma), which co-occurred with the origin of complete metamorphosis of the insect hosts, presumably between 280â¯Ma and 355â¯Ma (~270â¯Ma for Diptera). A co-phylogenetic pattern was recovered for the insects and their symbiotic gut fungi using the statistical method ParaFit. Ancestral state reconstructions of the symbiotic relationship suggest that the ancestor of the Chironomidae may have contributed to the initiation of these insect-fungus symbiotic interactions. Further sampling and sequencing of Smittium and allies as well as their hosts are needed to uncover more patterns and interactions that may occur in this type of symbiosis.
Assuntos
Biodiversidade , Fungos/classificação , Trato Gastrointestinal/microbiologia , Insetos/microbiologia , Filogenia , Simbiose , Animais , Teorema de Bayes , Fatores de TempoRESUMO
Scholars have made great advances in modeling and mapping ecosystem services, and in assigning economic values to these services. This modeling and valuation scholarship is often disconnected from evidence about how actual conservation programs have affected ecosystem services, however. Without a stronger evidence base, decision makers find it difficult to use the insights from modeling and valuation to design effective policies and programs. To strengthen the evidence base, scholars have advanced our understanding of the causal pathways between conservation actions and environmental outcomes, but their studies measure impacts on imperfect proxies for ecosystem services (e.g., avoidance of deforestation). To be useful to decision makers, these impacts must be translated into changes in ecosystem services and values. To illustrate how this translation can be done, we estimated the impacts of protected areas in Brazil, Costa Rica, Indonesia, and Thailand on carbon storage in forests. We found that protected areas in these conservation hotspots have stored at least an additional 1,000 Mt of CO2 in forests and have delivered ecosystem services worth at least $5 billion. This aggregate impact masks important spatial heterogeneity, however. Moreover, the spatial variability of impacts on carbon storage is the not the same as the spatial variability of impacts on avoided deforestation. These findings lead us to describe a research program that extends our framework to study other ecosystem services, to uncover the mechanisms by which ecosystem protection benefits humans, and to tie cost-benefit analyses to conservation planning so that we can obtain the greatest return on scarce conservation funds.
Assuntos
Conservação dos Recursos Naturais/economia , Ecossistema , Pobreza/economia , Brasil , Sequestro de Carbono , Análise Custo-Benefício , Costa Rica , Meio Ambiente , Política Ambiental/economia , Florestas , Humanos , Indonésia , Modelos Econômicos , TailândiaRESUMO
Harpellales, an early-diverging fungal lineage, is associated with the digestive tracts of aquatic arthropod hosts. Concurrent with the production and annotation of the first four Harpellales genomes, we discovered that Zancudomyces culisetae, one of the most widely distributed Harpellales species, encodes an insect-like polyubiquitin chain. Ubiquitin and ubiquitin-like proteins are universally involved in protein degradation and regulation of immune response in eukaryotic organisms. Phylogenetic analyses inferred that this polyubiquitin variant has a mosquito origin. In addition, its amino acid composition, animal-like secondary structure, as well as the fungal nature of flanking genes all further support this as a horizontal gene transfer event. The single-copy polyubiquitin gene from Z. culisetae has lower GC ratio compared with homologs of insect taxa, which implies homogenization of the gene since its putatively ancient transfer. The acquired polyubiquitin gene may have served to improve important functions within Z. culisetae, by perhaps exploiting the insect hosts' ubiquitin-proteasome systems in the gut environment. Preliminary comparisons among the four Harpellales genomes highlight the reduced genome size of Z. culisetae, which corroborates its distinguishable symbiotic lifestyle. This is the first record of a horizontally transferred ubiquitin gene from disease-bearing insects to the gut-dwelling fungal endobiont and should invite further exploration in an evolutionary context.
Assuntos
Culicidae/microbiologia , Fungos/genética , Transferência Genética Horizontal , Ubiquitina/genética , Animais , Evolução Biológica , Trato Gastrointestinal/microbiologia , Genoma , Fenótipo , Filogenia , Simbiose/genética , Ubiquitinação/genéticaRESUMO
Trichomycetes is a group of microorganisms that was considered a class of fungi comprising four orders of commensal, gut-dwelling endosymbionts obligately associated with arthropods. Since molecular phylogenies revealed two of those orders (Amoebidiales and Eccrinales="protist trichos") to be closely related to members of the protist class Ichthyosporea (=Mesomycetozoea), trichomycetes have been considered an ecological association of both early-diverging fungi and protists. Understanding of the taxonomy, evolution, and diversity of the protist trichos is lacking largely due to the difficulties inherent in species collection that have contributed to undersampling and understudy. The most recent classification divides the protist trichos between two families, Amoebidiidae and Eccrinidae (suborder Trichomycina, order Eccrinida). However, there is no comprehensive molecular phylogeny available for this group and major questions about the systematics of protist trichos remain unanswered. Therefore, we generated 18S and 28S rDNA sequences for 106 protist tricho samples and combined them with publicly available Eccrinida sequences for phylogenetic analyses. We also sequenced a conserved protein-coding gene (heat-shock 70 protein) to obtain a multigene data set. We conducted ancestral state reconstruction (ASR) and Bayesian tip-association significance test (BaTS) analyses by mapping six morphological and ecological characters onto the resulting phylogenetic trees. Our results demonstrate: (1) several ecological and morphological character states (habitat, host type, host stage at time of infestation, location within host, spore production, and growth form) are significantly correlated with the phylogeny, and (2) two additional protist tricho families should be incorporated into the taxonomy to reflect phylogenetic relationships. Our data suggest that an integrated strategy that combines morphological, ecological, and molecular characters is needed to further resolve and clarify the systematics of the Eccrinida.
Assuntos
Evolução Biológica , Fungos/classificação , Mesomycetozoea/classificação , Animais , Teorema de Bayes , DNA Ribossômico , Evolução Molecular , Fungos/genética , Mesomycetozoea/genética , FilogeniaRESUMO
To develop effective environmental policies, we must understand the mechanisms through which the policies affect social and environmental outcomes. Unfortunately, empirical evidence about these mechanisms is limited, and little guidance for quantifying them exists. We develop an approach to quantifying the mechanisms through which protected areas affect poverty. We focus on three mechanisms: changes in tourism and recreational services; changes in infrastructure in the form of road networks, health clinics, and schools; and changes in regulating and provisioning ecosystem services and foregone production activities that arise from land-use restrictions. The contributions of ecotourism and other ecosystem services to poverty alleviation in the context of a real environmental program have not yet been empirically estimated. Nearly two-thirds of the poverty reduction associated with the establishment of Costa Rican protected areas is causally attributable to opportunities afforded by tourism. Although protected areas reduced deforestation and increased regrowth, these land cover changes neither reduced nor exacerbated poverty, on average. Protected areas did not, on average, affect our measures of infrastructure and thus did not contribute to poverty reduction through this mechanism. We attribute the remaining poverty reduction to unobserved dimensions of our mechanisms or to other mechanisms. Our study empirically estimates previously unidentified contributions of ecotourism and other ecosystem services to poverty alleviation in the context of a real environmental program. We demonstrate that, with existing data and appropriate empirical methods, conservation scientists and policymakers can begin to elucidate the mechanisms through which ecosystem conservation programs affect human welfare.
Assuntos
Conservação dos Recursos Naturais/economia , Conservação dos Recursos Naturais/métodos , Ecossistema , Pobreza/prevenção & controle , Avaliação de Programas e Projetos de Saúde/estatística & dados numéricos , Costa Rica , Humanos , Pobreza/estatística & dados numéricos , Análise de Regressão , Fatores SocioeconômicosRESUMO
Urbanization has placed pressure on open space within and adjacent to cities. In recent decades, a greater awareness has developed to the fact that individuals derive multiple benefits from urban open space. Given the location, there is often a high opportunity cost to preserving urban open space, thus it is important for both public and private stakeholders to justify such investments. The goals of this study are twofold. First, we use detailed surveys and precise, accessible, mapping methods to demonstrate how travel-cost methods can be applied to the valuation of urban open space. Second, we assess the degree to which typical methods of estimating travel times, and thus travel costs, introduce bias to the estimates of welfare. The site we study is Taylor Mountain Regional Park, a 1100-acre space located immediately adjacent to Santa Rosa, California, which is the largest city (â¼170,000 population) in Sonoma County and lies 50 miles north of San Francisco. We estimate that the average per trip access value (consumer surplus) is $13.70. We also demonstrate that typical methods of measuring travel costs significantly understate these welfare measures. Our study provides policy-relevant results and highlights the sensitivity of urban open space travel-cost studies to bias stemming from travel-cost measurement error.
Assuntos
Viagem/economia , Urbanização , California , Cidades , Custos e Análise de Custo , HumanosRESUMO
Zygomycete fungi were classified as a single phylum, Zygomycota, based on sexual reproduction by zygospores, frequent asexual reproduction by sporangia, absence of multicellular sporocarps, and production of coenocytic hyphae, all with some exceptions. Molecular phylogenies based on one or a few genes did not support the monophyly of the phylum, however, and the phylum was subsequently abandoned. Here we present phylogenetic analyses of a genome-scale data set for 46 taxa, including 25 zygomycetes and 192 proteins, and we demonstrate that zygomycetes comprise two major clades that form a paraphyletic grade. A formal phylogenetic classification is proposed herein and includes two phyla, six subphyla, four classes and 16 orders. On the basis of these results, the phyla Mucoromycota and Zoopagomycota are circumscribed. Zoopagomycota comprises Entomophtoromycotina, Kickxellomycotina and Zoopagomycotina; it constitutes the earliest diverging lineage of zygomycetes and contains species that are primarily parasites and pathogens of small animals (e.g. amoeba, insects, etc.) and other fungi, i.e. mycoparasites. Mucoromycota comprises Glomeromycotina, Mortierellomycotina, and Mucoromycotina and is sister to Dikarya. It is the more derived clade of zygomycetes and mainly consists of mycorrhizal fungi, root endophytes, and decomposers of plant material. Evolution of trophic modes, morphology, and analysis of genome-scale data are discussed.
Assuntos
Fungos/classificação , Fungos/genética , Genoma Fúngico , FilogeniaRESUMO
Smittium, one of the first described genera of gut fungi, is part of a larger group of endosymbiotic microorganisms (Harpellales) that live predominantly in the digestive tracts of aquatic insects. As a diverse and species-rich taxon, Smittium has helped to advance our understanding of the gut fungi, in part due to the relative success of attempts to culture species of Smittium as compared to other members of Harpellales. Approximately 40% of the 81 known species of Smittium have been cultured. This is the first Smittium multigene dataset and phylogenetic analysis, using the 18S and 28S rRNA genes, as well as RPB1, RPB2, and MCM7 translated protein sequences. Several well-supported clades were recovered within Smittium. One includes the epitype S. mucronatum (the "True Smittium" clade), and another contains many species including S. simulii and S. orthocladii (the "Parasmittium" clade). Ancestral states were reconstructed for holdfast shape, thallus branching type, as well as asexual (trichospore) and sexual (zygospore) spore morphology. Two of these characters, holdfast shape and trichospore morphology, supported the split of the two main clades revealed by the molecular phylogeny, suggesting these are natural clades and these traits may have evolutionary and perhaps ecological significance.
Assuntos
Fungos/classificação , Insetos/microbiologia , Filogenia , Simbiose , Animais , DNA Fúngico/genética , Sistema Digestório/microbiologia , Fungos/genética , Genes Fúngicos , Modelos Genéticos , RNA Ribossômico 18S/genética , RNA Ribossômico 28S/genética , Análise de Sequência de DNARESUMO
Protected areas are the dominant approach to protecting biodiversity and the supply of ecosystem services. Because these protected areas are often placed in regions with widespread poverty and because they can limit agricultural development and exploitation of natural resources, concerns have been raised about their potential to create or reinforce poverty traps. Previous studies suggest that the protected area systems in Costa Rica and Thailand, on average, reduced deforestation and alleviated poverty. We examine these results in more detail by characterizing the heterogeneity of responses to protection conditional on observable characteristics. We find no evidence that protected areas trap historically poorer areas in poverty. In fact, we find that poorer areas at baseline seem to have the greatest levels of poverty reduction as a result of protection. However, we do find that the spatial characteristics associated with the most poverty alleviation are not necessarily the characteristics associated with the most avoided deforestation. We show how an understanding of these spatially heterogeneous responses to protection can be used to generate suitability maps that identify locations in which both environmental and poverty alleviation goals are most likely to be achieved.
Assuntos
Conservação dos Recursos Naturais , Pobreza/prevenção & controle , Costa Rica , Geografia , TailândiaRESUMO
Kickxellomycotina is a recently described subphylum encompassing four zygomycete orders (Asellariales, Dimargaritales, Harpellales, Kickxellales). These fungi are united by the formation of disciform septal pores containing lenticular plugs. Morphological diversification and life history evolution has made the relationships within and among the four orders difficult to resolve on those grounds alone. Here we infer the phylogeny of the Kickxellomycotina based on an eight-gene supermatrix including both ribosomal rDNA (18S, 28S, 5.8S) and protein sequences (MCM7, TSR1, RPB1, RPB2, ß-tubulin). The results of this study demonstrate that Kickxellomycotina is monophyletic and related to members of the Zoopagomycotina. Eight unique clades are distinguished in the Kickxellomycotina, including the four defined orders (Asellariales, Dimargaritales, Harpellales, Kickxellales) as well as four genera previously placed within two of these orders (Barbatospora, Orphella, Ramicandelaber, Spiromyces). Dimargaritales and Ramicandelaber are the earliest diverging members of the subphylum, although the relationship between these taxa remains uncertain. The remaining six clades form a monophyletic group, with Barbatospora diverging first. The next split divides the remaining members of the subphylum into two subclades: (i) Asellariales and Harpellales and (ii) Kickxellales, Orphella and Spiromyces. Estimation of ancestral states for four potentially informative morphological and ecological characters reveals that arthropod endosymbiosis might have been an important factor in the early evolution of the Kickxellomycotina.
Assuntos
Evolução Molecular , Fungos/classificação , Animais , Artrópodes/microbiologia , Sequência de Bases , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Proteínas Fúngicas/genética , Fungos/genética , Fungos/isolamento & purificação , Dados de Sequência Molecular , Técnicas de Tipagem Micológica , Filogenia , Análise de Sequência de DNA , Esporos Fúngicos , SimbioseRESUMO
Variation in the abiotic environment and host plant preferences can affect the composition of arbuscular mycorrhizal (AMF) assemblages. This study analyzed the AMF taxa present in soil and seedlings of Artemisia tridentata ssp. wyomingensis collected from sagebrush steppe communities in southwestern Idaho, USA. Our aims were to determine the AMF diversity within and among these communities and the extent to which preferential AMF-plant associations develop during seedling establishment. Mycorrhizae were identified using molecular methods following DNA extraction from field and pot culture samples. The extracted DNA was amplified using Glomeromycota specific primers, and identification of AMF was based on phylogenetic analysis of sequences from the large subunit-D2 rDNA region. The phylogenetic analyses revealed seven phylotypes, two within the Claroideoglomeraceae and five within the Glomeraceae. Four phylotypes clustered with known species including Claroideoglomus claroideum, Rhizophagus irregularis, Glomus microaggregatum, and Funneliformis mosseae. The other three phylotypes were similar to several published sequences not included in the phylogenetic analysis, but all of these were from uncultured and unnamed glomeromycetes. Pairwise distance analysis revealed some phylotypes with high genetic variation. The most diverse was the phylotype that included R. irregularis, which contained sequences showing pairwise differences up to 12 %. Most of the diversity in AMF sequences occurred within sites. The smaller genetic differentiation detected among sites was correlated with differences in soil texture. In addition, multiplication in pot cultures led to differentiation of AMF communities. Comparison of sequences obtained from the soil with those from A. tridentata roots revealed no significant differences between the AMF present in these samples. Overall, the sites sampled were dominated by cosmopolitan AMF taxa, and young seedlings of A. tridentata ssp. wyomingensis were colonized in relation to the abundance of these taxa in the soil.
Assuntos
Artemisia/microbiologia , Biodiversidade , Micorrizas/classificação , Micorrizas/isolamento & purificação , Microbiologia do Solo , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Clima Desértico , Idaho , Dados de Sequência Molecular , Filogenia , Raízes de Plantas/microbiologia , RNA Ribossômico/genética , Plântula/microbiologia , Análise de Sequência de DNARESUMO
Fungicides are moderately hydrophobic and have been detected in water and sediment, particularly in agricultural watersheds, but typically are not included in routine water quality monitoring efforts. This is despite their widespread use and frequent application to combat fungal pathogens. Whereas the efficacy of these compounds on fungal pathogens is well documented, little is known about their effects on nontarget fungi. This pilot study, a field survey in southwestern Idaho from April to December 2010 on four streams with varying pesticide inputs (two agricultural and two reference sites), was conducted to assess nontarget impact of fungicides on gut fungi, or trichomycetes. Tissues of larval black flies (Diptera: Simuliidae), hosts of gut fungi, were analyzed for pesticide accumulation. Fungicides were detected in hosts from streams within agricultural watersheds but were not detected in hosts from reference streams. Gut fungi from agricultural sites exhibited decreased percent infestation, density within the gut, and sporulation, and black fly tissues had elevated pesticide concentrations. Differences observed between the sites demonstrate a potential effect on this symbiotic system. Future research is needed to parse out the details of the complex biotic and abiotic relationships; however, these preliminary results indicate that impacts to nontarget organisms could have far-reaching consequences within aquatic ecosystems.
RESUMO
BACKGROUND: Multiple sclerosis (MS) is characterized by pathology in white matter (WM) and atrophy of grey matter (GM), but it remains unclear how these processes are related, or how they influence clinical progression. OBJECTIVE: To study the spatial and temporal relationship between GM atrophy and damage in connected WM in relapsing-remitting (RR) MS in relation to clinical progression. METHODS: Healthy control (HC) and early RRMS subjects visited our center twice with a 1-year interval for MRI and clinical examinations, including the Expanded Disability Status Scale (EDSS) and Multiple Sclerosis Functional Composite (MSFC) scores. RRMS subjects were categorized as MSFC decliners or non-decliners based on ΔMSFC over time. Ten deep (D)GM and 62 cortical (C) GM structures were segmented and probabilistic tractography was performed to identify the connected WM. WM integrity was determined per tract with, amongst others, fractional anisotropy (FA), mean diffusivity (MD), neurite density index (NDI), and myelin water fraction (MWF). Linear mixed models (LMMs) were used to investigate GM and WM differences between HC and RRMS, and between MSFC decliners and non-decliners. LMM was also used to test associations between baseline WM z-scores and changes in connected GM z-scores, and between baseline GM z-scores and changes in connected WM z-scores, in HC/RRMS subjects and in MSFC decliners/non-decliners. RESULTS: We included 13 HCs and 31 RRMS subjects with an average disease duration of 3.5 years and a median EDSS of 3.0. Fifteen RRMS subjects showed declining MSFC scores over time, and they showed higher atrophy rates and greater WM integrity loss compared to non-decliners. Lower baseline WM integrity was associated with increased CGM atrophy over time in RRMS, but not in HC subjects. This effect was only seen in MSFC decliners, especially when an extended WM z-score was used, which included FA, MD, NDI and MWF. Baseline GM measures were not significantly related to WM integrity changes over time in any of the groups. DISCUSSION: Lower baseline WM integrity was related to more cortical atrophy in RRMS subjects that showed clinical progression over a 1-year follow-up, while baseline GM did not affect WM integrity changes over time. WM damage, therefore, seems to drive atrophy more than conversely.
Assuntos
Esclerose Múltipla Recidivante-Remitente , Esclerose Múltipla , Substância Branca , Humanos , Esclerose Múltipla/complicações , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/patologia , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Progressão da Doença , Imageamento por Ressonância Magnética , Esclerose Múltipla Recidivante-Remitente/complicações , Atrofia/patologiaRESUMO
PURPOSE: The knowledge and attitude of participants toward clinical trials (CTs) are a key determinant in successful recruitment and retention. This study aimed to evaluate knowledge and awareness-attitude among the recruited CT participants about CTs. METHODS: This was a cross-sectional face-to-face survey comprising CT participants involved in the past or currently a part of a CT during this study within the Indian Ophthalmology Clinical Trial Network (IOCTN). A previously validated questionnaire was used, and data regarding demographics, knowledge, and awareness-attitude about CTs were collected. The total awareness-attitude score was used to determine the knowledge and awareness of the participants. RESULTS: A total of 121 subjects had participated in the study who were part of ongoing trials, of which only five participants had prior experience of CTs. The majority (90%) had knowledge about CTs, whereas only 7% had confirmed signing consent forms. The total awareness-attitude score significantly varied across locations (27% for the southern zone, 53% for the central zone, and 52% for the western zone), and this was negatively associated with education. The most negative attitude (38.6%) was observed regarding adequate information sharing among participants, whereas non-disruption of their routine family life (60.7%) and financial stability (67.6%) were the top most positive attitudes revealed during their participation. The participants' pre- and post-participation attitude toward CTs revealed a positive attitude. CONCLUSION: The factors influencing a participant's knowledge and attitudes toward CTs were revealed in the study. Furthermore, the need for awareness regarding benefits of CTs to the public, participant's rights, and their voluntary power were the major highlights.
Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Humanos , Estudos Transversais , Inquéritos e Questionários , Índia/epidemiologiaRESUMO
The Harpellales includes 38 genera of endosymbiotic microfungi associated with various Arthropoda. Smittium, the second genus to be described, is now also the most species rich of the order. Species of Smittium inhabit the digestive tracts of larval aquatic insects, especially lower Dipt era, worldwide. During the 75 y since the type, Smittium aruernense, was described a number of advances in our understanding of the gut fungi have unfolded, in whole or in part, with Smittium as a model for the fungal trichomycetes. This in part relates to the high number of successful isolation attempts, with about 40% of known species having been cultured, a total number that far exceeds any other genus of gut fungus. Many isolates of Smittium have been used in laboratory studies for ultrastructural. physiological, host feeding, serological, as well as isozyme, and now ongoing molecular systematic studies. Molecular studies have shown thai Smittium is polyphyletic but with consistent separation of Smittium culisetae, one of the most common and widespread species, from the remainder of Smittium. A brief overview of Smittium research is provided. Zygospore and trichospore morphology and molecular evidence (immunological, isozyme, DNA sequences and phyiogenetic analyses) are used to establish Zancudomyces and to accommodate Smittium culisetae. For the latter evidence, we include the first two-gene phylogenetic analysis, using combined 18S and 28S rRNA gene sequence data to show a cluster of Zancudomyces culisetae separate from Smittium. As the broadest taxon sampling of Smittium to date, this also serves a molecular systematic update toward revisionary syntheses of this and other Harpellales taxa.
Assuntos
Fungos/classificação , Fungos/isolamento & purificação , Insetos/microbiologia , Animais , Fungos/genética , História do Século XX , História do Século XXI , Dados de Sequência Molecular , Micologia/história , FilogeniaRESUMO
Purpose: Advances in patient treatment depend heavily on clinical trials (CTs). Patient volunteers for CT are tougher to recruit and retain. In order to administer CTs effectively, it is necessary to comprehend how the public views and perceives participating in them. The study assessed the perception and attitudes of patients and bystanders toward CTs in India. Methods: This was a multi-centric, cross-sectional study among patients and bystanders using a questionnaire that consisted of socio-demographic characteristics and questions on knowledge and attitude toward participation in CTs. The minimum sample size estimated for the survey was 750. Results: A total of 1260 respondents (patients and bystanders) had participated in the survey. 42% of total respondents were aware about CTs. Unawareness regarding (i) voluntary power of an individual to participate in a CT (only 47%), (ii) entitled benefits of free treatment and medical insurance during enrolment in a CT (only 47%), and (iii) only 16% of the respondents knew involvement of human subjects in CT were the major highlights among those who had prior knowledge about CTs. Education was the most pervasive factor in shaping positive perception among the respondents. Occupation was another ubiquitous factor in shaping their perception regarding CTs. Conclusion: The majority of respondents were not aware of CTs. The major concerns observed were time consumption and harmful nature of CTs that influenced their unwillingness to participate in CTs. Initiatives such as awareness campaigns and survey assessments that would result in scientifically effective health service policies would be strategic methods to enhance CT participation.