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1.
Sensors (Basel) ; 23(2)2023 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-36679443

RESUMEN

The potato cyst nematode (PCN), Globodera pallida, has acquired significant importance throughout Europe due to its widespread prevalence and negative effects on potato production. Thus, rapid and reliable diagnosis of PCN is critical during surveillance programs and for the implementation of control measures. The development of innovative technologies to overcome the limitations of current methodologies in achieving early detection is needed. Lab-on-a-chip devices can swiftly and accurately detect the presence of certain nucleotide sequences with high sensitivity and convert the presence of biological components into an understandable electrical signal by combining biosensors with microfluidics-based biochemical analysis. In this study, a specific DNA-probe sequence and PCR primers were designed to be used in a magnetoresistive biosensing platform to amplify the internal transcribed spacer region of the ribosomal DNA of G. pallida. Magnetic nanoparticles were used as the labelling agents of asymmetric PCR product through biotin−streptavidin interaction. Upon target hybridization to sensor immobilized oligo probes, the fringe field created by the magnetic nanoparticles produces a variation in the sensor's electrical resistance. The detection signal corresponds to the concentration of target molecules present in the sample. The results demonstrate the suitability of the magnetic biosensor to detect PCR target product and the specificity of the probe, which consistently distinguishes G. pallida (DV/V > 1%) from other cyst nematodes (DV/V < 1%), even when DNA mixtures were tested at different concentrations. This shows the magnetic biosensor's potential as a bioanalytical device for field applications and border phytosanitary inspections.


Asunto(s)
Solanum tuberosum , Tylenchoidea , Animales , Cuarentena , Tylenchoidea/genética , Reacción en Cadena de la Polimerasa/métodos , ADN
2.
Rev Invest Clin ; 74(3): 135-146, 2022 05 02.
Artículo en Inglés | MEDLINE | ID: mdl-35240755

RESUMEN

BACKGROUND: Information is needed on the safety and efficacy of direct discharge from the emergency department (ED) of patients with COVID-19 pneumonia. OBJECTIVES: The objectives of the study were to study the variables associated with discharge from the ED in patients presenting with COVID-19 pneumonia, and study ED revisits related to COVID-19 at 30 days (EDR30d). METHODS: Multicenter study of the SIESTA cohort including 1198 randomly selected COVID patients in 61 EDs of Spanish medical centers from March 1, 2020, to April 30, 2020. We collected baseline and related characteristics of the acute episode and calculated the adjusted odds ratios (aOR) for ED discharge. In addition, we analyzed the variables related to EDR30d in discharged patients. RESULTS: We analyzed 859 patients presenting with COVID-19 pneumonia, 84 (9.8%) of whom weredischarged from the ED. The variables independently associated with discharge were being a woman (aOR 1.890; 95%CI 1.176 3.037), age < 60 years (aOR 2.324; 95%CI 1.353-3.990), and lymphocyte count > 1200/mm3 (aOR 4.667; 95%CI 1.045-20.839). The EDR30d of the ED discharged group was 40.0%, being lower in women (aOR 0.368; 95%CI 0.142-0.953). A totalof 130 hospitalized patients died (16.8%) as did two in the group discharged from the ED (2.4%) (OR 0.121; 95%CI 0.029-0.498). CONCLUSION: Discharge from the ED in patients with COVID-19 pneumonia was infrequent and was associated with few variables of the episode. The EDR30d was high, albeit with a low mortality.


Asunto(s)
COVID-19 , Neumonía , Estudios de Cohortes , Servicio de Urgencia en Hospital , Femenino , Hospitalización , Humanos , Persona de Mediana Edad , Alta del Paciente , Estudios Prospectivos , Estudios Retrospectivos
3.
Mol Plant Microbe Interact ; 34(6): 645-657, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33400561

RESUMEN

The root lesion nematode Pratylenchus penetrans is a migratory species that attacks a broad range of crops. Like other plant pathogens, P. penetrans deploys a battery of secreted protein effectors to manipulate plant hosts and induce disease. Although several candidate effectors of P. penetrans have been identified, detailed mechanisms of their functions and particularly their host targets remain largely unexplored. In this study, a repertoire of candidate genes encoding pioneer effectors of P. penetrans was amplified from mixed life stages of the nematode, and candidate effectors were cloned and subjected to transient expression in a heterologous host, Nicotiana benthamiana, using potato virus X-based gene vector. Among seven analyzed genes, the candidate effector designated as Ppen10370 triggered pleiotropic phenotypes substantially different from those produced by wild type infection. Transcriptome analysis of plants expressing Ppen10370 demonstrated that observed phenotypic changes were likely related to disruption of core biological processes in the plant due to effector-originated activities. Cross-species comparative analysis of Ppen10370 identified homolog gene sequences in five other Pratylenchus species, and their transcripts were found to be localized specifically in the nematode esophageal glands by in situ hybridization. RNA silencing of the Ppen10370 resulted in a significant reduction of nematode reproduction and development, demonstrating an important role of the esophageal gland effector for parasitism.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Asunto(s)
Proteínas del Helminto , Tylenchoidea , Animales , Perfilación de la Expresión Génica , Proteínas del Helminto/genética , Enfermedades de las Plantas , Nicotiana , Tylenchoidea/genética
4.
Artículo en Inglés | MEDLINE | ID: mdl-34287117

RESUMEN

An intracellular bacterium, strain IAST, was observed to infect several species of the plant-parasitic nematode genus Xiphinema (Xiphinema astaregiense, Xiphinema incertum, Xiphinema madeirense, Xiphinema pachtaicum, Xiphinema parapachydermum and Xiphinema vallense). The bacterium could not be recovered on axenic medium. The 16S rRNA gene sequence of IAST was found to be new, being related to the family Burkholderiaceae, class Betaproteobacteria. Fungal endosymbionts Mycoavidus cysteinexigens B1-EBT (92.9 % sequence identity) and 'Candidatus Glomeribacter gigasporarum' BEG34 (89.8 % identity) are the closest taxa and form a separate phylogenetic clade inside Burkholderiaceae. Other genes (atpD, lepA and recA) also separated this species from its closest relatives using a multilocus sequence analysis approach. These genes were obtained using a partial genome of this bacterium. The localization of the bacterium (via light and fluorescence in situ hybridization microscopy) is in the X. pachtaicum females clustered around the developing oocytes, primarily found embedded inside the epithelial wall cells of the ovaries, from where they are dispersed in the intestine. Transmission electron microscopy (TEM) observations supported the presence of bacteria inside the nematode body, where they occupy ovaries and occur inside the intestinal epithelium. Ultrastructural analysis of the bacterium showed cells that appear as mostly irregular, slightly curved rods with rounded ends, 0.8-1.2 µm wide and 2.5-6.0 µm long, possessing a typical Gram-negative cell wall. The peptidoglycan layer is, however, evident only occasionally and not detectable by TEM in most cells. Another irregularly occurring shell surrounding the endosymbiont cells or the cell clusters was also revealed, probably originating from the host cell membrane. Flagella or spore-like cells do not occur and the nucleoid is diffusely distributed throughout the cell. This endosymbiont is transmitted vertically through nematode generations. These results support the proposal of IAST as a new species, although its obligate intracellular and obligate endosymbiont nature prevented isolation of a definitive type strain. Strain IAST is therefore proposed as representing 'Candidatus Xiphinematincola pachtaicus' gen. nov., sp. nov.


Asunto(s)
Burkholderiaceae/clasificación , Nematodos/microbiología , Filogenia , Simbiosis , Animales , Técnicas de Tipificación Bacteriana , Composición de Base , Burkholderiaceae/aislamiento & purificación , Citrus/parasitología , ADN Bacteriano/genética , Ácidos Grasos/química , Femenino , Genes Bacterianos , Hibridación Fluorescente in Situ , ARN Ribosómico 16S/genética , Rizosfera , Análisis de Secuencia de ADN , España
5.
BMC Genomics ; 19(1): 553, 2018 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-30053797

RESUMEN

BACKGROUND: Plant-parasitic nematodes cause severe damage to a wide range of crop and forest species worldwide. The migratory endoparasitic nematode, Bursaphelenchus xylophilus, (pinewood nematode) is a quarantine pathogen that infects pine trees and has a hugely detrimental economic impact on the forestry industry. Under certain environmental conditions large areas of infected trees can be destroyed, leading to damage on an ecological scale. The interactions of B. xylophilus with plants are mediated by secreted effector proteins produced in the pharyngeal gland cells. Identification of effectors is important to understand mechanisms of parasitism and to develop new control measures for the pathogens. RESULTS: Using an approach pioneered in cyst nematodes, we have analysed the promoter regions of a small panel of previously validated pharyngeal gland cell effectors from B. xylophilus to identify an associated putative regulatory promoter motif: STATAWAARS. The presence of STATAWAARS in the promoter region of an uncharacterized gene is a predictor that the corresponding gene encodes a putatively secreted protein, consistent with effector function. Furthermore, we are able to experimentally validate that a subset of STATAWAARS-containing genes are specifically expressed in the pharyngeal glands. Finally, we independently validate the association of STATAWAARS with tissue-specific expression by directly sequencing the mRNA of pharyngeal gland cells. We combine a series of criteria, including STATAWAARS predictions and abundance in the gland cell transcriptome, to generate a comprehensive effector repertoire for B. xylophilus. The genes highlighted by this approach include many previously described effectors and a series of novel "pioneer" effectors. CONCLUSIONS: We provide a major scientific advance in the area of effector regulation. We identify a novel promoter motif (STATAWAARS) associated with expression in the pharyngeal gland cells. Our data, coupled with those from previous studies, suggest that lineage-specific promoter motifs are a theme of effector regulation in the phylum Nematoda.


Asunto(s)
Regiones Promotoras Genéticas , Tylenchida/genética , Animales , Motivos de Nucleótidos , Faringe/metabolismo , Transcriptoma , Tylenchida/metabolismo
6.
BMC Genomics ; 19(1): 603, 2018 08 10.
Artículo en Inglés | MEDLINE | ID: mdl-30097016

RESUMEN

Following publication of the original article [1], the authors reported that one of the authors' names was erroneously changed during proofing and published incorrectly. In this Correction the incorrect and correct author name are shown. The original publication of this article has been corrected.

7.
Chem Biodivers ; 14(1)2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27623247

RESUMEN

Pinewood nematode (PWN), Bursaphelenchus xylophilus, is the causal agent of pine wilt disease, a serious threat to global forest populations of conifers, especially Pinus spp. A time-course study of the essential oils (EOs) of 2-year-old Pinus halepensis, Pinus pinaster, Pinus pinea and Pinus sylvestris following inoculation with the PWN was performed. The constitutive and nematode inoculation induced EOs components were analyzed at both the wounding or inoculation areas and at the whole plant level. The enantiomeric ratio of optically active main EOs components was also evaluated. External symptoms of infection were observed only in P. pinaster and P. sylvestris 21 and 15 days after inoculation, respectively. The EO composition analysis of uninoculated and unwounded plants revealed the occurrence of chemotypes for P. pinaster, P. halepensis and P. sylvestris, whereas P. pinea showed a homogenous EO composition. When whole plants were evaluated for EO and monoterpene hydrocarbon enantiomeric chemical composition, no relevant qualitative and quantitative differences were found. Instead, EO analysis of inoculated and uninoculated wounded areas revealed an increase of sesquiterpenes and diterpenic compounds, especially in P. pinea and P. halepensis, comparatively to healthy whole plants EOs.


Asunto(s)
Aceites Volátiles/análisis , Pinus/química , Animales , Monoterpenos/análisis , Nematodos/patogenicidad , Infecciones por Nematodos/metabolismo , Aceites Volátiles/química , Enfermedades de las Plantas/parasitología , Terpenos/análisis
8.
Proteomics ; 16(6): 1006-14, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26718462

RESUMEN

The Pine Wood Nematode (PWN) Bursaphelenchus xylophilus is a severe forest pathogen in countries where it has been introduced and is considered a worldwide quarantine organism. In this study, protein markers for differentiating populations of this nematode were identified by studying differences among four selected Iberian and one American population. These populations were compared by quantitative proteomics (iTRAQ). From a total of 2860 proteins identified using the public database from the B. xylophilus genome project, 216 were unambiguous and significantly differentially regulated in the studied populations. Comparisons of their pairwise ratio were statistically treated and supported in order to convert them into discrete character states, suggesting that 141 proteins were not informative as population specific markers. Application of the Character Compatibility methodology on the remaining 75 proteins (belonging to families with different biological functions) excludes 27 which are incompatible among them. Considering only the compatible proteins, the method selects a subset of 30 specific unique protein markers which allowed the compared classification of the Iberian isolates. This approach makes it easier search for diagnostic tools and phylogenetic inference within species and populations of a pathogen exhibiting a high level of genetic diversity.


Asunto(s)
Biomarcadores/análisis , Proteínas del Helminto/análisis , Proteoma/análisis , Proteómica/métodos , Tylenchida/química , Animales , Biomarcadores/química , Proteínas del Helminto/química , Filogenia , Proteoma/química , Espectrometría de Masas en Tándem , Tylenchida/clasificación
9.
BMC Genomics ; 17: 301, 2016 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-27108223

RESUMEN

BACKGROUND: Pine wilt disease (PWD) is a worldwide threat to pine forests, and is caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus. Bacteria are known to be associated with PWN and may have an important role in PWD. Serratia sp. LCN16 is a PWN-associated bacterium, highly resistant to oxidative stress in vitro, and which beneficially contributes to the PWN survival under these conditions. Oxidative stress is generated as a part of the basal defense mechanism used by plants to combat pathogenic invasion. Here, we studied the biology of Serratia sp. LCN16 through genome analyses, and further investigated, using reverse genetics, the role of two genes directly involved in the neutralization of H2O2, namely the H2O2 transcriptional factor oxyR; and the H2O2-targeting enzyme, catalase katA. RESULTS: Serratia sp. LCN16 is phylogenetically most closely related to the phytosphere group of Serratia, which includes S. proteamaculans, S. grimessi and S. liquefaciens. Likewise, Serratia sp. LCN16 shares many features with endophytes (plant-associated bacteria), such as genes coding for plant polymer degrading enzymes, iron uptake/transport, siderophore and phytohormone synthesis, aromatic compound degradation and detoxification enzymes. OxyR and KatA are directly involved in the high tolerance to H2O2 of Serratia sp. LCN16. Under oxidative stress, Serratia sp. LCN16 expresses katA independently of OxyR in contrast with katG which is under positive regulation of OxyR. Serratia sp. LCN16 mutants for oxyR (oxyR::int(614)) and katA (katA::int(808)) were sensitive to H2O2 in relation with wild-type, and both failed to protect the PWN from H2O2-stress exposure. Moreover, both mutants showed different phenotypes in terms of biofilm production and swimming/swarming behaviors. CONCLUSIONS: This study provides new insights into the biology of PWN-associated bacteria Serratia sp. LCN16 and its extreme resistance to oxidative stress conditions, encouraging further research on the potential role of this bacterium in interaction with PWN in planta environment.


Asunto(s)
Proteínas Bacterianas/genética , Estrés Oxidativo , Peroxidasas/genética , Enfermedades de las Plantas/microbiología , Serratia/genética , Factores de Transcripción/genética , Tylenchida/microbiología , Animales , Proteínas Bacterianas/metabolismo , Técnicas de Inactivación de Genes , Genoma Bacteriano , Peróxido de Hidrógeno/química , Peroxidasas/metabolismo , Filogenia , Pinus/microbiología , Pinus/parasitología , Serratia/clasificación , Factores de Transcripción/metabolismo
10.
Environ Microbiol ; 18(12): 5265-5276, 2016 12.
Artículo en Inglés | MEDLINE | ID: mdl-27768814

RESUMEN

The aim of this study is to understand the biological role of Serratia quinivorans BXF1, a bacterium commonly found associated with Bursaphelenchus xylophilus, the plant parasitic nematode responsible for pine wilt disease. Therefore, we studied strain BXF1 effect in pine wilt disease. We found that strain BXF1 promoted in vitro nematode reproduction. Moreover, the presence of bacteria led to the absence of nematode chitinase gene (Bxcht-1) expression, suggesting an effect for bacterial chitinase in nematode reproduction. Nevertheless, strain BXF1 was unable to colonize the nematode interior, bind to its cuticle with high affinity or protect the nematode from xenobiotic stress. Interestingly, strain BXF1 was able to promote tomato and pine plant-growth, as well as to colonize its interior, thus, acting like a plant-growth promoting endophyte. Consequently, strain BXF1 failed to induce wilting symptoms when inoculated in pine shoot artificial incisions. This bacterium also presented strong antagonistic activities against fungi and bacteria isolated from Pinus pinaster. Our results suggest that B. xylophilus does not possess a strict symbiotic community capable of inducing pine wilt disease symptoms as previously hypothesized. We show that bacteria like BXF1, which possess plant-growth promoting and antagonistic effects, may be opportunistically associated with B. xylophilus, possibly acquired from the bacterial endophytic community of the host pine.


Asunto(s)
Endófitos/fisiología , Pinus/microbiología , Pinus/parasitología , Enfermedades de las Plantas/parasitología , Serratia/fisiología , Tylenchida/fisiología , Animales , Endófitos/genética , Endófitos/aislamiento & purificación , Pinus/crecimiento & desarrollo , Serratia/genética , Serratia/aislamiento & purificación , Simbiosis , Tylenchida/genética , Tylenchida/aislamiento & purificación
11.
Microb Ecol ; 72(3): 669-81, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27461253

RESUMEN

Pine wilt disease (PWD) results from the interaction of three elements: the pathogenic nematode, Bursaphelenchus xylophilus; the insect-vector, Monochamus sp.; and the host tree, mostly Pinus species. Bacteria isolated from B. xylophilus may be a fourth element in this complex disease. However, the precise role of bacteria in this interaction is unclear as both plant-beneficial and as plant-pathogenic bacteria may be associated with PWD. Using whole genome sequencing and phenotypic characterization, we were able to investigate in more detail the genetic repertoire of Serratia marcescens PWN146, a bacterium associated with B. xylophilus. We show clear evidence that S. marcescens PWN146 is able to withstand and colonize the plant environment, without having any deleterious effects towards a susceptible host (Pinus thunbergii), B. xylophilus nor to the nematode model C. elegans. This bacterium is able to tolerate growth in presence of xenobiotic/organic compounds, and use phenylacetic acid as carbon source. Furthermore, we present a detailed list of S. marcescens PWN146 potentials to interfere with plant metabolism via hormonal pathways and/or nutritional acquisition, and to be competitive against other bacteria and/or fungi in terms of resource acquisition or production of antimicrobial compounds. Further investigation is required to understand the role of bacteria in PWD. We have now reinforced the theory that B. xylophilus-associated bacteria may have a plant origin.


Asunto(s)
Endófitos , Estilo de Vida , Infecciones Oportunistas , Pinus/microbiología , Serratia marcescens/aislamiento & purificación , Serratia marcescens/fisiología , Serratia marcescens/patogenicidad , Tylenchida/microbiología , Animales , Antiinfecciosos , Antinematodos/farmacología , Secuencia de Bases , Clasificación , Escarabajos/microbiología , ADN Bacteriano , Genes Bacterianos , Interacciones Huésped-Parásitos/fisiología , Insectos Vectores/microbiología , Microscopía Confocal , Microscopía Electrónica de Rastreo , Anotación de Secuencia Molecular , Nematodos/patogenicidad , Filogenia , Pinus/parasitología , Enfermedades de las Plantas/microbiología , Serratia marcescens/genética , Árboles/microbiología , Árboles/parasitología , Tylenchida/efectos de los fármacos , Tylenchida/patogenicidad
12.
Planta ; 241(6): 1325-36, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25677754

RESUMEN

MAIN CONCLUSION: Co-cultures of Pinus pinaster with Bursaphelenchus xylophilus were established as a biotechnological tool to evaluate the effect of nematotoxics addition in a host/parasite culture system. The pinewood nematode (PWN), Bursaphelenchus xylophilus, the causal agent of pine wilt disease (PWD), was detected for the first time in Europe in 1999 spreading throughout the pine forests in Portugal and recently in Spain. Plant in vitro cultures may be a useful experimental system to investigate the plant/nematode relationships in loco, thus avoiding the difficulties of field assays. In this study, Pinus pinaster in vitro cultures were established and compared to in vivo 1 year-old plantlets by analyzing shoot structure and volatiles production. In vitro co-cultures were established with the PWN and the effect of the phytoparasite on in vitro shoot structure, water content and volatiles production was evaluated. In vitro shoots showed similar structure and volatiles production to in vivo maritime pine plantlets. The first macroscopic symptoms of PWD were observed about 4 weeks after in vitro co-culture establishment. Nematode population in the culture medium increased and PWNs were detected in gaps of the callus tissue and in cavities developed from the degradation of cambial cells. In terms of volatiles main components, plantlets, P. pinaster cultures, and P. pinaster with B. xylophilus co-cultures were all ß- and α-pinene rich. Co-cultures may be an easy-to-handle biotechnological approach to study this pathology, envisioning the understanding of and finding ways to restrain this highly devastating nematode.


Asunto(s)
Biotecnología/métodos , Técnicas de Cocultivo/métodos , Pinus/crecimiento & desarrollo , Enfermedades de las Plantas/parasitología , Tylenchida/fisiología , Animales , Pinus/ultraestructura , Brotes de la Planta/crecimiento & desarrollo , Brotes de la Planta/ultraestructura , Compuestos Orgánicos Volátiles/análisis , Agua
13.
Crit Rev Biotechnol ; 35(1): 114-28, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23937251

RESUMEN

The impact of nanotechnology in all areas of science and technology is evident. The expanding availability of a variety of nanostructures with properties in the nanometer size range has sparked widespread interest in their use in biotechnological systems, including the field of environmental remediation. Nanomaterials can be used as catalysts, adsorbents, membranes, water disinfectants and additives to increase catalytic activity and capability due to their high specific surface areas and nanosize effects. Thus, nanomaterials appear promising for new effective environmental technologies. Definitely, nanotechnology applications for site remediation and wastewater treatment are currently in research and development stages, and new innovations are underway. The synthesis of metallic nanoparticles has been intensively developed not only due to its fundamental scientific interest but also for many technological applications. The use of microorganisms in the synthesis of nanoparticles is a relatively new eco-friendly and promising area of research with considerable potential for expansion. On the other hand, chemical synthesis occurs generally under extreme conditions (e.g. pH, temperature) and also chemicals used may have associated environmental and human health impacts. This review is an overview of current research worldwide on the use of microorganisms during the biosynthesis of metallic nanoparticles and their unique properties that make them good candidates for many applications, including in biotechnology.


Asunto(s)
Bacterias/metabolismo , Hongos/metabolismo , Nanopartículas del Metal , Biotecnología , Biotransformación , Nanopartículas del Metal/química
14.
Appl Microbiol Biotechnol ; 99(12): 5307-16, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25666680

RESUMEN

A survey in 16 activated sludge wastewater treatment plants (WWTP) was conducted to contribute to the knowledge of the environmental parameters that determine the composition of the filamentous community. A total of 128 samples of mixed liquor from municipal WWTP were collected during 2 years, and 22 filamentous morphotypes were identified. The most frequent and abundant filamentous bacteria were, in both cases and by this order, type 0041/0675, type 0092, Microthrix parvicella and 1851, nocardioforms and Haliscomenobacter hydrossis. Concerning dominance, type 1851 was the most frequently dominant morphotype, followed by M. parvicella and types 0092 and 0041/0675. These were also, and by this order, the dominant morphotypes during bulking occurrences. Significant correlations were obtained between the abundance of filamentous bacteria and environmental parameters, but multivariate statistical analysis only confirmed the correlation between type 0092 and Sludge Volume Index (SVI), emphasizing the association of this filament with bulking. The discussion of the results in light of published works was complicated by the random use of terms such as frequency, abundance, and dominance with different and often unclear meanings. This reinforces the need of clarifying these terms when discussing the causes of filamentous overgrowth in WWTP.


Asunto(s)
Bacterias/aislamiento & purificación , Aguas del Alcantarillado/microbiología , Bacterias/clasificación , Bacterias/genética , Ecosistema , Portugal , Aguas del Alcantarillado/análisis , Aguas Residuales/análisis , Aguas Residuales/microbiología , Purificación del Agua/instrumentación , Purificación del Agua/métodos
15.
J Math Biol ; 70(1-2): 197-212, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24526259

RESUMEN

This work deals with mathematical modeling through branching processes. We consider sexually reproducing animal populations where, in each generation, the number of progenitor couples is determined in a non-predictable environment. By using a class of two-sex branching processes, we describe their demographic dynamics and provide several probabilistic and inferential contributions. They include results about the extinction of the population and the estimation of the offspring distribution and its main moments. We also present an application to salmonid populations.


Asunto(s)
Modelos Biológicos , Salmonidae/fisiología , Animales , Extinción Biológica , Femenino , Masculino , Conceptos Matemáticos , Modelos Estadísticos , Oncorhynchus kisutch/fisiología , Océano Pacífico , Dinámica Poblacional/estadística & datos numéricos , Reproducción , Estadísticas no Paramétricas , Procesos Estocásticos
16.
Mol Phylogenet Evol ; 70: 120-9, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24076248

RESUMEN

Tandemly repeated sequences known as satellite DNA (satDNA) generally exhibit complex evolutionary patterns of concerted evolution in which mutations are homogenized and fixed in a stochastic process of molecular drive. Here, the nucleotidic variability of the MspI satDNA family of the pinewood nematode Bursaphelenchus xylophilus is analyzed in order to understand the evolutionary dynamics of satDNA at the intraspecific level. A total of 425 MspI monomer units, either PCR-amplified from isolates of local (Peninsula of Setúbal, Portugal) or worldwide origin, or retrieved from the B. xylophilus genome sequence, were characterized and compared. Whatever their origin, sliding window analysis of sequence variability patterns among monomers revealed low, moderate and highly variant domains, indicating that variable levels of evolutionary constraint may act upon the entire monomers. The phylogenetic inference based on the different sets of MspI satDNA family for this species shows a broad polymorphism of the individual monomers, which were distributed into four main clusters. However, such clustering appeared independent from the geographic origin of the nematodes, and could not discriminate isolates or groups of geographically close isolates. Rather, the formation of different phylogenetic groups within this satDNA family suggests an a priori embodying of a set of diverging repeats from a common ancestor satDNA library, which have been differently amplified along the evolutionary pathway of this species. The present work improves knowledge on the evolutionary dynamics of satDNA at the intraspecific level, and provides new information on satDNA sequence variability among natural populations sampled at a local geographic scale.


Asunto(s)
ADN Satélite/genética , Filogenia , Tylenchida/genética , Animales , Genoma , Análisis de Secuencia de ADN
17.
Math Biosci Eng ; 21(6): 6407-6424, 2024 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-39176432

RESUMEN

This research focused its interest on the mathematical modeling of the demographic dynamics of semelparous biological species through branching processes. We continued the research line started in previous papers, providing new methodological contributions of biological and ecological interest. We determined the probability distribution associated with the number of generations elapsed before the possible extinction of the population in its natural habitat. We mathematically modeled the phenomenon of populating or repopulating habitats with semelparous species. We also proposed estimates for the offspring parameters governing the reproductive strategies of the species. To this purpose, we used the maximum likelihood and Bayesian estimation methodologies. The statistical results are illustrated through a simulated example contextualized with Labord chameleon (Furcifer labordi) species.


Asunto(s)
Teorema de Bayes , Simulación por Computador , Ecosistema , Dinámica Poblacional , Reproducción , Animales , Reproducción/fisiología , Femenino , Masculino , Funciones de Verosimilitud , Lagartos/fisiología , Modelos Biológicos , Algoritmos , Probabilidad
18.
Plants (Basel) ; 13(5)2024 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-38475572

RESUMEN

Plant-parasitic nematodes (PPNs) are highly damaging pests responsible for heavy losses in worldwide productivity in a significant number of important plant crops. Common pest management strategies rely on the use of synthetic chemical nematicides, which have led to serious concerns regarding their impacts on human health and the environment. Plant natural products, or phytochemicals, can provide a good source of agents for sustainable control of PPNs, due to their intrinsic characteristics such as higher biodegradability, generally low toxicity for mammals, and lower bioaccumulation in the environment. In this work, the nematicidal activity of 39 phytochemicals was determined against the root-lesion nematode (RLN) Pratylenchus penetrans using standard direct and indirect contact methodologies. Overall, the RLN was tolerant to the tested phytochemicals at the highest concentration, 2 mg/mL, seldom reaching full mortality. However, high activities were obtained for benzaldehyde, carvacrol, 3-octanol, and thymol, in comparison to other phytochemicals or the synthetic nematicide oxamyl. These phytochemicals were seen to damage nematode internal tissues but not its cuticle shape. Also, the environmental and (eco)toxicological parameters reported for these compounds suggest lower toxicity and higher safety of use than oxamyl. These compounds appear to be good candidates for the development of biopesticides for a more sustainable pest management strategy.

19.
Front Bioeng Biotechnol ; 12: 1337879, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38303911

RESUMEN

The combination of a sensitive and specific magnetoresistive sensing device with an easy DNA extraction method and a rapid isothermal amplification is presented here targeting the on-site detection of Globodera pallida, a potato endoparasitic nematode. FTA-cards were used for DNA extraction, LAMP was the method developed for DNA amplification and a nanoparticle functionalized magnetic-biosensor was used for the detection. The combinatorial effect of these three emerging technologies has the capacity to detect G. pallida with a detection limit of one juvenile, even when mixed with other related species. This combined system is far more interesting than what a single technology can provide. Magnetic biosensors can be combined with any DNA extraction protocol and LAMP forming a new solution to target G. pallida. The probe designed in this study consistently distinguished G. pallida (∆Vac binding/Vac sensor above 1%) from other cyst nematodes (∆Vac binding/Vac sensor below 1%). It was confirmed that DNA either extracted with FTA-cards or Lab extraction Kit was of enough quantity and quality to detect G. pallida whenever present (alone or in mixed samples), ensuring probe specificity and sensitivity. This work provides insights for a new strategy to construct advanced devices for pathogens in-field diagnostics. LAMP runs separately but can be easily integrated into a single device.

20.
Emergencias ; 36(3): 211-221, 2024 Jun.
Artículo en Español, Inglés | MEDLINE | ID: mdl-38818987

RESUMEN

SUMMARY: COVID-19 continues to pose a significant threat: mortality stands at nearly twice that of influenza, and the incidence rate is growing as the population's vaccination rate decreases, particularly in Spain and other areas of Europe. Given this situation, it is vitally important know whether medical protocols are consistent and appropriately implemented by health care staff in the interest of preventing possible inefficiency or inequity. Physicians from hospital emergency departments met to study their hospitals' usual clinical practices for managing SARS-CoV-2 infection and to determine their expert opinions on the use of antiviral agents. The participating physicians then reached consensus on evidencebased recommendations for strategies that would optimize emergency treatment.


RESUMEN: Actualmente, la COVID-19 sigue representando una amenaza significativa, con una mortalidad cercana al doble de la ocasionada por la gripe y con una incidencia variable debido a una disminución en la tasa de vacunación de la población, especialmente en el contexto europeo y español. Ante este panorama, es de vital importancia comprobar que los protocolos médicos están consolidados y son debidamente implementados por los profesionales sanitarios, con la finalidad de evitar posibles ineficiencias o inequidades. A través de reuniones con profesionales de urgencias se han observado las prácticas clínicas habituales en los servicios de urgencias hospitalarios para pacientes con infección por SARS-CoV-2, con la finalidad de comprender la perspectiva de estos profesionales acerca del uso de antivirales y, tras un consenso de expertos basados en la evidencia actual, se han generado estas de recomendaciones para poder enfocar estrategias que optimicen el tratamiento de los pacientes en estos servicios.


Asunto(s)
Antivirales , Tratamiento Farmacológico de COVID-19 , Humanos , Antivirales/uso terapéutico , España/epidemiología , Medicina de Emergencia/normas , COVID-19/epidemiología , COVID-19/prevención & control , Servicio de Urgencia en Hospital , SARS-CoV-2
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