El decaimiento y muerte de encinas en tres dehesas de la provincia de Huelva

Oak decline affecting three holm oak plots in Huelva has been studied along the last two years. Syndromes of dieback and sudden death have been observed. In both cases, unspecific aerial symptoms were associated with root rot. Characterisation of fungal isolates from necrotic roots led us to identify Phytophthora cinnamomi A2 consistently associated with the disease. Optimum growth temperatures of these isolates were very high (30.2°C). Inoculation tests under controlled conditions demonstrated the pathogenicity of the isolates in holm and cork oak seedlings. Symptomatology associated with other biotic factors of oak decline were never recorded, so in this case, forest decline model has not been the best choice to explain the disease observed. In fact, oak defoliation and mortality can be well explained as a disease of single aetiology caused by P. cinnamomi. Nevertheless, some abiotic factors as drought or the alternancy of drought and wet periods in the region seem to play an important role.Durante dos años se ha estudiado la evolución del decaimiento de encinas en tres dehesas de la comarca del Andévalo (Huelva). Se ha observado tanto el síndrome de muerte lenta como el de muerte súbita, con una sintomatologia aérea inespecífica asociada a la podredumbre del sistema radical. La caracterización de los aislados fúngicos obtenidos a partir de las raíces necrosadas ha permitido su identificación como Phytophthora cinnamomi A2, con temperaturas óptimas de crecimiento elevadas (30.2° C). La patogenicidad de estos aislados en encina y alcornoque se ha puesto de manifiesto en experimentos de inoculación de plantones en condiciones controladas. En ningún caso fue posible localizar síntomas ni signos de otros agentes bióticos implicados en la seca de los Quercus, por lo que, en el caso de las dehesas estudiadas, el modelo de decaimiento forestal no ha resultado la mejor explicación para la enfermedad observada. La explicación del problema se podría reducir a una enfermedad de etiología simple, cuyo agente causal es P. cinnamomi, y en la que algunos factores, como la sequía o la alternancia de períodos secos y lluviosos, pueden tener una influencia decisiva

The interplay of phonology and orthography in visual cognate word recognition: an ERP study

This study examined the role of phonological and orthographic overlap in the recognition of cognate words by recording electrophysiological and behavioral data. One hundred and ninety-two words were selected: 96 cognate words listed according to their phonological and orthographic overlap vs. 96 noncognate words. Twenty-four proficient European Portuguese-English bilinguals performed a silent reading task with a masked priming paradigm. The results showed that phonology interacts with semantic activation at N400 modulations. Phonological priming effects were dependent on the orthographic overlap of cognate words. Thus, the distinctive processing of cognate words seems to be due to their cross-linguistic similarity, which is consistent with a localist connectionist account on cognate representation and processing.The research reported in this paper wasfunded by FCT (Foundation for Science and Technology), by NSRF (National Strategic Reference Framework), by COMPETE (Operational Agenda for Competitiveness Factors), a program created by the EU as part of the European Regional Development Fund (ERDF), (PTDC/PSI-PCO/104671/2008) and by the Spanish Ministry of Education and Science (PSI2009–12616) and Plan E

DESCRIPCIÓN ANATOMOPATOLÓGICA DE LESIONES POR HELMINTOS GASTROINTESTINALES EN TORTUGAS MOTELO (Chelonoidis denticulata)

The present aimed to identify and describe lesions caused by helminths in motelo tortoises(Chelonoidis denticulata). Forty gastrointestinal tracts were collected at Belen market inIquitos, Peru where this species is sold for meat consumption. The macroscopic analysisshowed that 42.5, 70.0, and 100% of the stomachs, small intestine and large intestinerespectively were parasitizedor affected by pathological –possibly due to parasites–changes like nodules, blackish coloration areas, ulcers, perforations, thickening,congestion and hemorrhagic areas. Parasites of 11 species were collected: Labidurisgulosa, Labiduris zschokkei, Labiduris irineuta, Atractis marquezi, Klossinemellatravassosi, Sauricola sauricola, Chapiniella variabilis, Angusticaecum holopterumand Ophidascaris arndti (Nematoda), and Halltrema avitellina and Helicotrema spirale(Trematoda). Histologically, an invasion of the four gastrointestinal layers by parasiticstructures compatible with H. avitellina (and its eggs), C. variabilis, S. sauricola and unundetermined species of atractideus was observed mostly surrounded by inflammatoryexudates formed by eosinophiles, giant cells, lymphocytes and connective tissue. Also,the presence of eosinophilic infiltrate in the mucosa was found as a response to thecontact with O. arndti and H. spirale. The results showed that all animals presentedparasitic lesions in the large intestine, most of them severe; whereas lesions in stomachand small intestine were mainly moderate and mild.El trabajo tuvo por objetivo identificar y describir las lesiones ocasionadas por helmintos en tortugas motelo (Chelonoidis denticulata). Se colectaron 40 tractos gastrointestinales de tortugas en el mercado de Belén, Iquitos, Perú, donde esta especie es comercializada como carne de consumo. El análisis macroscópico mostró que el 42.5, 70.0 y 100% de los estómagos, intestino delgado e intestino grueso, respectivamente, se encontraban parasitados o presentaban cambios patológicos de posible origen parasitario como nódulos, áreas de coloración negruzca, úlceras, perforaciones, engrosamiento, congestión y focos hemorrágicos. Se identificaron 11 especies de helmintos: Labiduris gulosa, Labiduris zschokkei, Labiduris irineuta, Atractismarquezi, Klossinemella travassosi, Sauricola sauricola, Chapiniella variabilis, Angusticaecum holopterum y Ophidascaris arndti (Nematoda), y Halltrema avitellinay Helicotrema spirale (Trematoda). Histológicamente, se evidenció la invasión de las cuatro túnicas gastrointestinales por estructuras parasitarias compatibles con H.avitellina (y sus huevos), C. variabilis, S. sauricola y una especie no determinada de atractídeo, rodeadas principalmente por exudados inflamatorios compuestos de eosinófilos, células gigantes, linfocitos y tejido conjuntivo. Asimismo, se observó la presencia de infiltrado eosinofílico en la mucosa como respuesta al contacto con O.arndti y H. spirale. Los resultados indican que todos los individuos presentaron lesiones parasitarias en intestino grueso, siendo la mayoría de grado severo, mientras que las lesiones en estómago e intestino delgado fueron mayormente de grado moderado y leve

Potential community-based control by use of plastic film to block aedes aegypti (L.) egg adhesion

Abstract. Monitoring and control programs for yellow fever mosquito, Aedes aegypti (L.), usually do not focus on the egg as a potential target for control. The egg is the most numerous life stage but is invisible to conventional inspection by a sticky pad that attaches it. This laboratory study evaluated the potential ovicidal effect of five commonly used plastics. Plastic liners in oviposition containers were exposed to gravid female mosquitoes in an insectary. The percentage of eggs that hatched was recorded. The plastic liners altered the places where eggs were laid, i.e., 27.0% were glued onto the plastic film, 70.0% remained floating, and 3.0% were submerged. Vinyl blocked most egg adhesion, with a mean of 7.05 ± 10.1 eggs, compared to 170.7 ± 68.6 eggs for the check. Pooled numbers of glued, floating, and submerged eggs showed fewest eggs hatched on vinyl or low-density polyethylene, resulting in the death of 94.7% of the embryos. Plastics waterproofing property might be blocking the hyaluronic acid, the component of the sticky substance of mosquito eggs. Results demonstrated the potential use of plastic strips as an ovicide. Plastics should be studied further for use in community-based programs to control dengue

Influencia del cultivo de Lupinus luteus L. en la densidad de inóculo de Phytophthora cinnamomi en suelos de dehesa

Phytophthora cinnamomi es un patógeno que causa podredumbre radical en el arbolado de la dehesa y también en Lupinus luteus, cultivo frecuente en dehesas de Andalucía occidental. En dehesas que mostraban distintas situaciones en cuanto a decaimiento del arbolado y severidad de la enfermedad en el altramuz, el aislamiento y conteo de colonias de P. cinnamomi a partir de muestras de suelo ha mostrado la capacidad del cultivo herbáceo para mantener o incrementar la densidad de inóculo y así potenciar la infección de las encinas. Los resultados obtenidos desaconsejan el cultivo de esta leguminosa en dehesas con presencia del patógeno en el suelo, tanto si el arbolado sufre la enfermedad radical o no

Variant antigen repertoires in Trypanosoma congolense populations and experimental infections can be profiled from deep sequence data using universal protein motifs

African trypanosomes are vector-borne hemoparasites of humans and animals. In the mammal, parasites evade the immune response through antigenic variation. Periodic switching of the Variant Surface Glycoprotein (VSG) coat covering their cell surface allows sequential expansion of serologically distinct parasite clones. Trypanosome genomes contain many hundreds of VSG genes, subject to rapid changes in nucleotide sequence, copy number and chromosomal position. Thus, analysing, or even quantifying, VSG diversity over space and time presents an enormous challenge to conventional techniques. Indeed, previous population genomic studies have overlooked this vital aspect of pathogen biology for lack of analytical tools. Here we present a method for analysing population-scale VSG diversity in Trypanosoma congolense from deep sequencing data. Previously, we suggested that T. congolense VSG segregate into defined 'phylotypes' that do not recombine. In our dataset comprising 41 T. congolense genome sequences from across Africa, these phylotypes are universal and exhaustive. Screening sequence contigs with diagnostic protein motifs accurately quantifies relative phylotype frequencies, providing a metric of VSG diversity, called the 'Variant Antigen Profile'. We applied our metric to VSG expression in the tsetse fly, showing that certain, rare VSG phylotypes may be preferentially expressed in infective, metacyclic-stage parasites. Hence, variant antigen profiling accurately and rapidly determines VSG gene and transcript repertoire from sequence data, without need for manual curation or highly contiguous sequences. It offers a tractable approach to measuring VSG diversity across strains and during infections, which is imperative to understanding the host-parasite interaction at population and individual scales. [Abstract copyright: Published by Cold Spring Harbor Laboratory Press.

SCIENTIFIC COUNCIL MEETING – 20 - 24 SEPTEMBER 2021

Report of the Scientific Council meeting held by WebEx from 20 to 24 September 2021Versión del editor

Determination of antibodies against Neospora caninum in water buffaloes (Bubalus bubalis) in the Peruvian Amazonia

La neosporosis es una parasitosis de importancia en el sector ganadero por ser causante de abortos y mortalidad neonatal. El objetivo del estudio fue determinar la presencia de anticuerpos contra Neospora caninum en búfalos de agua procedentes de cinco centros de crianza ubicados en el distrito Jenaro Herrera, departamento de Loreto, Perú, en el año 2008. Se evaluaron 83 muestras de suero, obtenidas de búfalas en edad productiva, criadas para la producción de leche. Las muestras se evaluaron por ELISA indirecto e inmunofluorescencia indirecta (IFI). No se halló evidencia de anticuerpos contra N. caninum a las diluciones 1:25 y 1:100 utilizando ELISA indirecto, así como a la dilución 1:100 con IFI. Los resultados sugieren una baja o nula exposición de los búfalos de agua al parásito en la zona estudiada.Neosporosis is an important parasitic disease that causes reproductive problems as abortion and neonatal mortality in diary cattle. The aim of the study was to determine the presence of antibodies against Neospora caninum in water buffaloes reared in five farms located in Jenaro Herrera district, Loreto, Peru in 2008. Blood samples were collected from 83 female dairy buffalo older than 2 years. Serum samples were tested by indirect ELISA and immunnefluorescent antibody test (IFAT). None of sera presented antibodies against N. caninum to the dilution 1:25 and 1:100 using indirect ELISA or to the dilution 1:100 by IFAT. The results suggest a low exposition of water buffaloes to N. caninum in the studied area