RESUMO
The efficient natural transformation of Neisseria meningitidis allows the rapid construction of bacterial mutants in which the genes of interest are interrupted or replaced by antibiotic-resistance cassettes. However, this proved to be a double-edged sword, i.e., although facilitating the genetic characterization of this important human pathogen, it has limited the development of strategies for constructing markerless mutants without antibiotic-resistance markers. In addition, efficient tools for complementation or labeling are also lacking in N. meningitidis. In this study, we significantly expand the meningococcal genetic toolbox by developing new and efficient tools for the construction of markerless mutants (using a dual counterselection strategy), genetic complementation (using integrative vectors), and cell labeling (using a self-labeling protein tag). This expanded toolbox paves the way for more in-depth genetic characterization of N. meningitidis and might also be useful in other Neisseria species.IMPORTANCENeisseria meningitidis and Neisseria gonorrhoeae are two important human pathogens. Research focusing on these bacteria requires genetic engineering, which is facilitated by their natural ability to undergo transformation. However, the ease of mutant engineering has led the Neisseria community to neglect the development of more sophisticated tools for gene editing, particularly for N. meningitidis. In this study, we have significantly expanded the meningococcal genetic toolbox by developing novel and efficient tools for markerless mutant construction, genetic complementation, and cell tagging. This expanded toolbox paves the way for more in-depth genetic characterization of N. meningitidis and might also be useful in other Neisseria species.
RESUMO
Neisseria meningitidis utilizes type IV pili (T4P) to adhere to and colonize host endothelial cells, a process at the heart of meningococcal invasive diseases leading to meningitis and sepsis. T4P are polymers of an antigenically variable major pilin building block, PilE, plus several core minor pilins that initiate pilus assembly and are thought to be located at the pilus tip. Adhesion of N. meningitidis to human endothelial cells requires both PilE and a conserved noncore minor pilin PilV, but the localization of PilV and its precise role in this process remains to be clarified. Here, we show that both PilE and PilV promote adhesion to endothelial vessels in vivo. The substantial adhesion defect observed for pilV mutants suggests it is the main adhesin. Consistent with this observation, superresolution microscopy showed the abundant distribution of PilV throughout the pilus. We determined the crystal structure of PilV and modeled it within the pilus filament. The small size of PilV causes it to be recessed relative to adjacent PilE subunits, which are dominated by a prominent hypervariable loop. Nonetheless, we identified a conserved surface-exposed adhesive loop on PilV by alanine scanning mutagenesis. Critically, antibodies directed against PilV inhibit N. meningitidis colonization of human skin grafts. These findings explain how N. meningitidis T4P undergo antigenic variation to evade the humoral immune response while maintaining their adhesive function and establish the potential of this highly conserved minor pilin as a vaccine and therapeutic target for the prevention and treatment of N. meningitidis infections.
Assuntos
Aderência Bacteriana , Proteínas de Bactérias/fisiologia , Fímbrias Bacterianas/fisiologia , Neisseria meningitidis/fisiologia , Animais , Anticorpos/uso terapêutico , Proteínas de Bactérias/química , Proteínas de Bactérias/ultraestrutura , Linhagem Celular , Avaliação Pré-Clínica de Medicamentos , Feminino , Fímbrias Bacterianas/química , Fímbrias Bacterianas/ultraestrutura , Humanos , Infecções Meningocócicas/tratamento farmacológico , Camundongos SCIDRESUMO
IMPORTANCE: Marine hypoxia is a threat for corals but has remained understudied in tropical regions where coral reefs are abundant. Though microbial symbioses can alleviate the effects of ecological stress, we do not yet understand the taxonomic or functional response of the coral microbiome to hypoxia. In this study, we experimentally lowered oxygen levels around Siderastrea siderea and Agaricia lamarcki colonies in situ to observe changes in the coral microbiome in response to deoxygenation. Our results show that hypoxia triggers a stochastic change of the microbiome overall, with some bacterial families changing deterministically after just 48 hours of exposure. These families represent an increase in anaerobic and opportunistic taxa in the microbiomes of both coral species. Thus, marine deoxygenation destabilizes the coral microbiome and increases bacterial opportunism. This work provides novel and fundamental knowledge of the microbial response in coral during hypoxia and may provide insight into holobiont function during stress.
Assuntos
Antozoários , Microbiota , Humanos , Animais , Antozoários/microbiologia , Recifes de Corais , Bactérias/genética , HipóxiaRESUMO
Black band disease is a globally distributed and easily recognizable coral disease. Despite years of study, the etiology of this coral disease, which impacts dozens of stony coral species, is not completely understood. Although black band disease mats are predominantly composed of the cyanobacterial species Roseofilum reptotaenium, other filamentous cyanobacterial strains and bacterial heterotrophs are readily detected. Through chemical ecology and metagenomic sequencing, we uncovered cryptic strains of Roseofilum species from Siderastrea siderea corals that differ from those on other corals in the Caribbean and Pacific. Isolation of metabolites from Siderastrea-derived Roseofilum revealed the prevalence of unique forms of looekeyolides, distinct from previously characterized Roseofilum reptotaenium strains. In addition, comparative genomics of Roseofilum strains showed that only Siderastrea-based Roseofilum strains have the genetic capacity to produce lasso peptides, a family of compounds with diverse biological activity. All nine Roseofilum strains examined here shared the genetic capacity to produce looekeyolides and malyngamides, suggesting these compounds support the ecology of this genus. Similar biosynthetic gene clusters are not found in other cyanobacterial genera associated with black band disease, which may suggest that looekeyolides and malyngamides contribute to disease etiology through yet unknown mechanisms.
Assuntos
Antozoários , Cianobactérias , Animais , Antozoários/microbiologia , Cianobactérias/metabolismo , Genômica , MetagenômicaRESUMO
The seat-dip effect (SDE) occurs when low-frequency sounds propagate through the seating area of a performance space. The physical aspects governing the effect still puzzle acousticians mostly due to the large variety of seating configurations. In this study, the SDE is investigated in three parameterized hall models using the finite-difference time-domain method to simulate a large number of seat configurations in order to quantify the contribution of different geometric properties related to the seating area. The results show that the step size defining the inclination angle of the seating area and the opening underneath the seats (or underpass) are significant factors contributing to the SDE, whereas the stage height and the source position are found to be less important. The results also demonstrate that with an underpass greater than the step size, the first frequency dip occurring between 80 and 100 Hz is mitigated regardless of the hall type considered. The phenomenon is also found to be predominant in the early part of the room response. Visualizations of spatial and time-frequency evolution in the halls are also provided for the cases where the seat properties are found to visibly affect the magnitude spectrum.
RESUMO
Emerging diseases can have devastating consequences for wildlife and require a rapid response. A critical first step towards developing appropriate management is identifying the etiology of the disease, which can be difficult to determine, particularly early in emergence. Gathering and synthesizing existing information about potential disease causes, by leveraging expert knowledge or relevant existing studies, provides a principled approach to quickly inform decision-making and management efforts. Additionally, updating the current state of knowledge as more information becomes available over time can reduce scientific uncertainty and lead to substantial improvement in the decision-making process and the application of management actions that incorporate and adapt to newly acquired scientific understanding. Here we present a rapid prototyping method for quantifying belief weights for competing hypotheses about the etiology of disease using a combination of formal expert elicitation and Bayesian hierarchical modeling. We illustrate the application of this approach for investigating the etiology of stony coral tissue loss disease (SCTLD) and discuss the opportunities and challenges of this approach for addressing emergent diseases. Lastly, we detail how our work may apply to other pressing management or conservation problems that require quick responses. We found the rapid prototyping methods to be an efficient and rapid means to narrow down the number of potential hypotheses, synthesize current understanding, and help prioritize future studies and experiments. This approach is rapid by providing a snapshot assessment of the current state of knowledge. It can also be updated periodically (e.g., annually) to assess changes in belief weights over time as scientific understanding increases. Synthesis and applications: The rapid prototyping approaches demonstrated here can be used to combine knowledge from multiple experts and/or studies to help with fast decision-making needed for urgent conservation issues including emerging diseases and other management problems that require rapid responses. These approaches can also be used to adjust belief weights over time as studies and expert knowledge accumulate and can be a helpful tool for adapting management decisions.
Assuntos
Antozoários , Animais , Teorema de Bayes , IncertezaRESUMO
Stony corals (Scleractinia) are invertebrates that form symbiotic relationships with eukaryotic algal endosymbionts and the prokaryotic microbiome. The microbiome has the potential to produce bioactive natural products providing defense and resilience to the coral host against pathogenic microorganisms, but this potential has not been extensively explored. Bacterial pathogens can pose a significant threat to corals, with some species implicated in primary and opportunistic infections of various corals. In response, probiotics have been proposed as a potential strategy to protect corals in the face of increased incidence of disease outbreaks. In this study, we screened bacterial isolates from healthy and diseased corals for antibacterial activity. The bioactive extracts were analyzed using untargeted metabolomics. Herein, an UpSet plot and hierarchical clustering analyses were performed to identify isolates with the largest number of unique metabolites. These isolates also displayed different antibacterial activities. Through application of in silico and experimental approaches coupled with genome analysis, we dereplicated natural products from these coral-derived bacteria from Florida's coral reef environments. The metabolomics approach highlighted in this study serves as a useful resource to select probiotic candidates and enables insights into natural product-mediated chemical ecology in holobiont symbiosis.
Assuntos
Antozoários , Produtos Biológicos , Animais , Antozoários/microbiologia , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Bactérias/genética , Produtos Biológicos/metabolismo , Produtos Biológicos/farmacologia , Metabolômica , SimbioseRESUMO
Room acoustic simulations using the finite-difference time-domain method on a wide frequency range can be computationally expensive and typically contain numerical dispersion. Numerical dispersion can be audible and, thus, constitutes an artifact in auralizations. There is a need to measure perceptual thresholds for numerical dispersion to achieve an optimal balance between computational complexity and audibility of dispersion. This work measures the perceptual detection thresholds for numerical dispersion in binaural auralizations of two acoustically different rooms. Numerical dispersion is incorporated into measured binaural room impulse responses (BRIRs) by the means of filters that represent the dispersion that plane waves experience, which propagate in the simulation in the direction of the worst-case dispersion error. The results show that the perceptual detection threshold is generally lower for the most reverberant room and greatly depends on the source signal independently of the room in which the threshold is measured. It is the most noticeable in the pure BRIRs, i.e., with an impulse as source signal, and almost unnoticeable with speech. The results also show that there was no statistical evidence that the perceptual thresholds for the conditions where numerical dispersion was present or absent in the direct path of the BRIRs be different.
Assuntos
Acústica , Percepção da Fala , Estimulação Acústica/métodos , Percepção da Fala/fisiologia , Fala , Simulação por Computador , Mascaramento Perceptivo/fisiologia , Limiar Auditivo/fisiologiaRESUMO
Staphylococcus epidermidis is a pathogen emerging worldwide as a leading cause of health care-associated infections. A standardized high-resolution typing method to document transmission and dissemination of multidrug-resistant S. epidermidis strains is needed. Our aim was to provide a core genome multilocus sequence typing (cgMLST) scheme for S. epidermidis to improve the international surveillance of S. epidermidis We defined a cgMLST scheme based on 699 core genes and used it to investigate the population structure of the species and the genetic relatedness of isolates recovered from infants hospitalized in several wards of a French hospital. Our results show the long-lasting endemic persistence of S. epidermidis clones within and across wards of hospitals and demonstrate the ability of our cgMLST approach to identify and track these clones. We made the scheme publicly available through the Institut Pasteur BIGSdb server (http://bigsdb.pasteur.fr/epidermidis/). This tool should enable international harmonization of the epidemiological surveillance of multidrug-resistant S. epidermidis clones. By comparing gene distribution among infection and commensal isolates, we also confirmed the association of the mecA locus with infection isolates and of the fdh gene with commensal isolates. (This study has been registered at ClinicalTrials.gov under registration no. NCT03374371.).
Assuntos
Infecções Estafilocócicas , Staphylococcus epidermidis , Células Clonais , Genoma Bacteriano/genética , Hospitais , Humanos , Tipagem de Sequências Multilocus , Infecções Estafilocócicas/epidemiologia , Staphylococcus epidermidis/genéticaRESUMO
BACKGROUND: Chronic lung infection in cystic fibrosis (CF) patients by Staphylococcus aureus is a well-established epidemiological fact. Indeed, S. aureus is the most commonly identified pathogen in the lungs of CF patients. Improving our understanding of the mechanisms associated with the persistence of S. aureus is therefore an important issue. METHODS: We selected pairs of sequential S. aureus isolates from 3 patients with CF and from 1 patient with non-CF chronic lung disease. We used a combination of genomic, proteomic, and metabolomic approaches with functional assays for in-depth characterization of S. aureus long-term persistence. RESULTS: In this study, we show that late S. aureus isolates from CF patients have an increased ability for intracellular survival in CF bronchial epithelial-F508del cells compared to ancestral early isolates. Importantly, the increased ability to persist intracellularly was confirmed for S. aureus isolates within the own-patient F508del epithelial cells. An increased ability to form biofilm was also demonstrated. Furthermore, we identified the underlying genetic modifications that induce altered protein expression profiles and notable metabolic changes. These modifications affect several metabolic pathways and virulence regulators that could constitute therapeutic targets. CONCLUSIONS: Our results strongly suggest that the intracellular environment might constitute an important niche of persistence and relapse necessitating adapted antibiotic treatments.
Assuntos
Staphylococcus aureus/efeitos dos fármacos , Adaptação Fisiológica/efeitos dos fármacos , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Linhagem Celular , Células Cultivadas , Cromatografia Líquida , Humanos , Proteogenômica/métodos , Proteômica/métodos , Espectrometria de Massas em TandemRESUMO
Neisseria meningitidis is a commensal of human nasopharynx. In some circumstances, this bacteria can invade the bloodstream and, after crossing the blood brain barrier, the meninges. A filamentous phage, designated MDAΦ for Meningococcal Disease Associated, has been associated with invasive disease. In this work we show that the prophage is not associated with a higher virulence during the bloodstream phase of the disease. However, looking at the interaction of N. meningitidis with epithelial cells, a step essential for colonization of the nasopharynx, we demonstrate that the presence of the prophage, via the production of viruses, increases colonization of encapsulated meningococci onto monolayers of epithelial cells. The analysis of the biomass covering the epithelial cells revealed that meningococci are bound to the apical surface of host cells by few layers of heavily piliated bacteria, whereas, in the upper layers, bacteria are non-piliated but surrounded by phage particles which (i) form bundles of filaments, and/or (ii) are in some places associated with bacteria. The latter are likely to correspond to growing bacteriophages during their extrusion through the outer membrane. These data suggest that, as the biomass increases, the loss of piliation in the upper layers of the biomass does not allow type IV pilus bacterial aggregation, but is compensated by a large production of phage particles that promote bacterial aggregation via the formation of bundles of phage filaments linked to the bacterial cell walls. We propose that MDAΦ by increasing bacterial colonization in the mucosa at the site-of-entry, increase the occurrence of diseases.
Assuntos
Inovirus/fisiologia , Infecções Meningocócicas/microbiologia , Neisseria meningitidis/patogenicidade , Neisseria meningitidis/virologia , Animais , Aderência Bacteriana , Células Epiteliais/microbiologia , Feminino , Fímbrias Bacterianas/fisiologia , Humanos , Camundongos , Camundongos SCID , Nasofaringe/microbiologia , Neisseria meningitidis/crescimento & desenvolvimento , Neisseria meningitidis/fisiologia , Prófagos/fisiologia , VirulênciaRESUMO
Black band disease (BBD), a lethal, polymicrobial disease consortium dominated by the cyanobacterium Roseofilum reptotaenium, kills many species of corals worldwide. To uncover chemical signals or cytotoxins that could be important in proliferation of Roseofilum and the BBD layer, we examined the secondary metabolites present in geographically diverse collections of BBD from Caribbean and Pacific coral reefs. Looekeyolide A (1), a 20-membered macrocyclic compound formed by a 16-carbon polyketide chain, 2-deamino-2-hydroxymethionine, and d-leucine, and its autoxidation product looekeyolide B (2) were extracted as major compounds (â¼1 mg g-1 dry wt) from more than a dozen field-collected BBD samples. Looekeyolides A and B were also produced by a nonaxenic R. reptotaenium culture under laboratory conditions at similar concentrations. R. reptotaenium genomes that were constructed from four different metagenomic data sets contained a unique nonribosomal peptide/polyketide biosynthetic cluster that is likely responsible for the biosynthesis of the looekeyolides. Looekeyolide A, which readily oxidizes to looekeyolide B, may play a biological role in reducing H2O2 and other reactive oxygen species that could occur in the BBD layer as it overgrows and destroys coral tissue.
Assuntos
Antozoários/microbiologia , Cianobactérias/metabolismo , Metagenômica/métodos , Policetídeos/metabolismo , Animais , Recifes de Corais , Compostos Macrocíclicos/metabolismo , OxirreduçãoRESUMO
Stable associations between plants and microbes are critical to promoting host health and productivity. The objective of this work was to test the hypothesis that restructuring of the core microbiota may be associated with the progression of huanglongbing (HLB), the devastating citrus disease caused by Liberibacter asiaticus, Liberibacter americanus, and Liberibacter africanus The microbial communities of leaves (n = 94) and roots (n = 79) from citrus trees that varied by HLB symptom severity, cultivar, location, and season/time were characterized with Illumina sequencing of 16S rRNA genes. The taxonomically rich communities contained abundant core members (i.e., detected in at least 95% of the respective leaf or root samples), some overrepresented site-specific members, and a diverse community of low-abundance variable taxa. The composition and diversity of the leaf and root microbiota were strongly associated with HLB symptom severity and location; there was also an association with host cultivar. The relative abundance of Liberibacter spp. among leaf microbiota positively correlated with HLB symptom severity and negatively correlated with alpha diversity, suggesting that community diversity decreases as symptoms progress. Network analysis of the microbial community time series identified a mutually exclusive relationship between Liberibacter spp. and members of the Burkholderiaceae, Micromonosporaceae, and Xanthomonadaceae This work confirmed several previously described plant disease-associated bacteria, as well as identified new potential implications for biological control. Our findings advance the understanding of (i) plant microbiota selection across multiple variables and (ii) changes in (core) community structure that may be a precondition to disease establishment and/or may be associated with symptom progression.IMPORTANCE This study provides a comprehensive overview of the core microbial community within the microbiomes of plant hosts that vary in extent of disease symptom progression. With 16S Illumina sequencing analyses, we not only confirmed previously described bacterial associations with plant health (e.g., potentially beneficial bacteria) but also identified new associations and potential interactions between certain bacteria and an economically important phytopathogen. The importance of core taxa within broader plant-associated microbial communities is discussed.
Assuntos
Bactérias/isolamento & purificação , Citrus/microbiologia , Microbiota , Doenças das Plantas/microbiologia , Bactérias/classificação , Bactérias/genética , Biodiversidade , DNA Bacteriano/genética , Filogenia , Folhas de Planta/microbiologia , RNA Ribossômico 16S/genéticaRESUMO
Warm fluids emanating from hydrothermal vents can be used as windows into the rocky subseafloor habitat and its resident microbial community. Two new vent systems on the Mid-Cayman Rise each exhibits novel geologic settings and distinctively hydrogen-rich vent fluid compositions. We have determined and compared the chemistry, potential energy yielding reactions, abundance, community composition, diversity, and function of microbes in venting fluids from both sites: Piccard, the world's deepest vent site, hosted in mafic rocks; and Von Damm, an adjacent, ultramafic-influenced system. Von Damm hosted a wider diversity of lineages and metabolisms in comparison to Piccard, consistent with thermodynamic models that predict more numerous energy sources at ultramafic systems. There was little overlap in the phylotypes found at each site, although similar and dominant hydrogen-utilizing genera were present at both. Despite the differences in community structure, depth, geology, and fluid chemistry, energetic modelling and metagenomic analysis indicate near functional equivalence between Von Damm and Piccard, likely driven by the high hydrogen concentrations and elevated temperatures at both sites. Results are compared with hydrothermal sites worldwide to provide a global perspective on the distinctiveness of these newly discovered sites and the interplay among rocks, fluid composition and life in the subseafloor.
Assuntos
Hidrogênio/análise , Fontes Hidrotermais/microbiologia , Animais , Biodiversidade , Fontes Hidrotermais/químicaRESUMO
The mechanism by which Neisseria meningitidis becomes invasive is not well understood. Comparative genomics identified the presence of an 8 kb island in strains belonging to invasive clonal complexes. This island was designated MDA for meningococcal disease associated. MDA is highly conserved among meningococcal isolates and its analysis revealed a genomic organization similar to that of a filamentous prophage such as CTXΦ of Vibrio cholerae. Subsequent molecular investigations showed that the MDA island has indeed the characteristics of a filamentous prophage, which can enter into a productive cycle and is secreted using the type IV pilus (tfp) secretin PilQ. At least three genes of the prophage are necessary for the formation of the replicative cytoplasmic form (orf1, orf2 and orf9). Immunolabelling of the phage with antibodies against the major capsid protein, ORF4, confirmed that filamentous particles, about 1200 nm long, covered with ORF4 are present at the bacterial surface forming bundles in some places and interacting with pili. The MDA bacteriophage is able to infect different N. meningitidis strains, using the type IV pili as a receptor via an interaction with the adsorption protein ORF6. Altogether, these data demonstrate that the MDA island encodes a functional prophage able to produce infectious filamentous phage particles.
Assuntos
Sítios de Ligação Microbiológicos/genética , Inovirus/genética , Neisseria meningitidis/genética , Neisseria meningitidis/virologia , Prófagos/genética , Receptores Virais/genética , Sequência de Bases , DNA Viral/genética , Fímbrias Bacterianas/virologia , Infecções Meningocócicas/microbiologia , Neisseria meningitidis/patogenicidade , Análise de Sequência de DNARESUMO
Colloidal stability of IgG antibody solutions is important for pharmaceutical and medicinal applications. Solution pH and ionic strength are two key factors that affect the colloidal stability of protein solutions. In this work, we use a method based on the PEG-induced liquid-liquid phase separation to examine the effects of pH and ionic strength on the colloidal stability of IgG solutions. We found that at high ionic strength (≥0.25M), the colloidal stability of most of our IgGs is insensitive to pH, and at low ionic strength (≤0.15M), all IgG solutions are much more stable at pH 5 than at pH 7. In addition, the PEG-induced depletion force is less efficient in causing phase separation at pH 5 than at pH 7. In contrast to the native inter-protein interaction of IgGs, the effect of depletion force on phase separation of the antibody solutions is insensitive to ionic strength. Our results suggest that the long-range electrostatic inter-protein repulsion at low ionic strength stabilizes the IgG solutions at low pH. At high ionic strength, the short-range electrostatic interactions do not make a significant contribution to the colloidal stability for most IgGs with a few exceptions. The weaker effect of depletion force at lower pH indicates a reduction of protein concentration in the condensed phase. This work advances our basic understanding of the colloidal stability of IgG solutions and also introduces a practical approach to measuring protein colloidal stability under various solution conditions.
Assuntos
Imunoglobulina G/química , Concentração Osmolar , Polietilenoglicóis/farmacologia , Coloides , Humanos , Concentração de Íons de Hidrogênio , Modelos Moleculares , Conformação Proteica , Estabilidade Proteica/efeitos dos fármacos , Solubilidade , Soluções , TemperaturaRESUMO
Colloidal stability of antibody solutions, i.e., the propensity of the folded protein to precipitate, is an important consideration in formulation development of therapeutic monoclonal antibodies. In a protein solution, different pathways including crystallization, colloidal aggregation, and liquid-liquid phase separation (LLPS) can lead to the formation of precipitates. The kinetics of crystallization and aggregation are often slow and vary from protein to protein. Due to the diverse mechanisms of these protein condensation processes, it is a challenge to develop a standardized test for an early evaluation of the colloidal stability of antibody solutions. LLPS would normally occur in antibody solutions at sufficiently low temperature, provided that it is not preempted by freezing of the solution. Poly(ethylene glycol) (PEG) can be used to induce LLPS at temperatures above the freezing point. Here, we propose a colloidal stability test based on inducing LLPS in antibody solutions and measuring the antibody concentration of the dilute phase. We demonstrate experimentally that such a PEG-induced LLPS test can be used to compare colloidal stability of different antibodies in different solution conditions and can be readily applied to high-throughput screening. We have derived an equation for the effects of PEG concentration and molecular weight on the results of the LLPS test. Finally, this equation defines a binding energy in the condensed phase, which can be determined in the PEG-induced LLPS test. This binding energy is a measure of attractive interactions between antibody molecules and can be used for quantitative characterization of the colloidal stability of antibody solutions.
Assuntos
Anticorpos/química , Coloides/química , Polietilenoglicóis/química , Soluções/química , Soluções Farmacêuticas/químicaRESUMO
Incidents of coral disease are on the rise. However, in the absence of a surrogate animal host, understanding of the interactions between coral pathogens and their hosts remains relatively limited, compared to other pathosystems of similar global importance. A tropical sea anemone, Aiptasia pallida, has been investigated as a surrogate model to study certain aspects of coral biology. Therefore, to test whether the utility of this surrogate model can be extended to study coral diseases, in the present study, we tested its susceptibility to common coral pathogens (Vibrio coralliilyticus and Vibrio shiloi) as well as polymicrobial consortia recovered from the Caribbean Yellow Band Disease (CYBD) lesions. A. pallida was susceptible to each of the tested pathogens. A. pallida responded to the pathogens with darkening of the tissues (associated with an increased melanization) and retraction of tentacles, followed by complete disintegration of polyp tissues. Loss of zooxanthellae was not observed; however, the disease progression pattern is consistent with the behavior of necrotizing pathogens. Virulence of some coral pathogens in Aiptasia was paralleled with their glycosidase activities.
Assuntos
Anêmonas-do-Mar/microbiologia , Vibrio/patogenicidade , Animais , Antozoários/microbiologia , Interações Hospedeiro-Patógeno , Melaninas/biossíntese , Consórcios Microbianos , Anêmonas-do-Mar/metabolismo , Estresse Fisiológico , Temperatura , VirulênciaRESUMO
Pathogen genomic epidemiology has the potential to provide a deep understanding of population dynamics, facilitating strategic planning of interventions, monitoring their impact, and enabling timely responses, and thereby supporting control and elimination efforts of parasitic tropical diseases. Plasmodium vivax, responsible for most malaria cases outside Africa, shows high genetic diversity at the population level, driven by factors like sub-patent infections, a hidden reservoir of hypnozoites, and early transmission to mosquitoes. While Latin America has made significant progress in controlling Plasmodium falciparum, it faces challenges with residual P. vivax. To characterize genetic diversity and population structure and dynamics, we have analyzed the largest collection of P. vivax genomes to date, including 1474 high-quality genomes from 31 countries across Asia, Africa, Oceania, and America. While P. vivax shows high genetic diversity globally, Latin American isolates form a distinctive population, which is further divided into sub-populations and occasional clonal pockets. Genetic diversity within the continent was associated with the intensity of transmission. Population differentiation exists between Central America and the North Coast of South America, vs. the Amazon Basin, with significant gene flow within the Amazon Basin, but limited connectivity between the Northwest Coast and the Amazon Basin. Shared genomic regions in these parasite populations indicate adaptive evolution, particularly in genes related to DNA replication, RNA processing, invasion, and motility - crucial for the parasite's survival in diverse environments. Understanding these population-level adaptations is crucial for effective control efforts, offering insights into potential mechanisms behind drug resistance, immune evasion, and transmission dynamics.