65 research outputs found

    A field comparison of different olive (Olea europaea L.) cultivars as host of the ash whitefly Siphoninus phillyreae (Haliday)

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    La mosca blanca del fresno, Siphoninus phillyreae (Haliday) , es una especie polífaga invasiva que causa graves daños en sus hospedadores, entre ellos el olivo (Olea europaea L.). El uso del hospedador por parte de S. phillyreae fue observado en tres cultivares de olivo (Arauco, Arbequina y Aloreña) en el norte de la provincia de La Rioja (Argentina) durante 2007 y 2008. De cada cultivar se muestrearon seis plantas infestadas y de cada planta se tomaron ocho hojas. De cada hoja se registró la abundancia de adultos y estados inmaduros de la mosca blanca que fueron comparadas entre los cultivares mediante modelos lineales generales y mixtos. Los resultados obtenidos mostraron diferencias significativas entre las densidades de adultos y ninfas de S. phillyreae en los distintos cultivares de olivo analizados. Dichos resultados indican que este insecto realiza un uso diferente de los cultivares de olivo, siendo Arauco y Arbequina las variedades hospedadoras más utilizadas en la zona de estudio.The ash whitefly, Siphoninus phillyreae (Haliday) is an invasive polyphagous species that causes serious damage to their hosts, including olive (Olea europaea L.). Host use by S. phillyreae was observed in three olive cultivars (Arauco, Arbequina y Aloreña) in North of La Rioja province (Argentina) during 2007 and 2008. Eight leaves of six infested plants of each cultivar were sampled. Adults and inmature stages abundances of each leaf were recorded. These abundances per cultivar were compared using general linear mixed model. The results showed significant differences between the densities of adults and nymphs of S. phillyreae in each of the olive cultivars analyzed. Thus, our results indicate that this insect makes a different use of the olive cultivars, Arauco and Arbequina being the most used in the study area.Fil: Pedemonte, María Laura. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales.Fil: Bruno, Marina Anabel. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales.Fil: Grilli, Mariano Pablo. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales

    Antagonism and modes of action of Chaetomium globosum species group, potential biocontrol agent of barley foliar diseases

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    Antagonismo y mecanismos de acción de hongos del grupo de especies Chaetomium globosum, potenciales biocontroladores de enfermedades fúngicas foliares de la cebada. La “mancha en red y la “mancha borrosa” son enfermedades foliares de cebada causadas por Drechslera teres y Bipolaris sorokiniana, respectivamente. Una alternativa para su manejo es el control biológico. El objetivo de este trabajo fue identificar dos aislamientos del género Chaetomium (C2 y C5), endofíticos de plántulas de cebada y estudiar sus interacciónes in vitro con D. teres y B. sorokiniana, aisladas de semillas del mismo hospedante. Todos los microorganismos se caracterizaron cultural y morfológicamente. Los aislamientos de Chaetomium además se caracterizaron molecularmente. Se realizaron pruebas de cultivos duales y se registraron los efectos del antagonista a nivel microscópico en la morfología de los patógenos. Los resultados confirmaron la identidad de los patógenos y de los aislamientos de Chaetomium spp. como Chaetomium globosum grupo de especies. Bipolaris sorokiniana fue inhibida en un 30% por C2 y en un 31.2 % por C5 respecto al control. D.teres fue inhibida en un 40% por C2 y en un 36% por C5 en referencia al control. Los mecanismos de acción frente a B. sorokiniana fueron antibiosis y competencia. Microscopicamente se observaron conidios aberrantes. Frente a D. teres se registró competencia y micoparasitismo. Microscópicamente se evidenció plasmólisis, enrollamiento y pigmentación anaranjada.“Net blotch” (Drechslera teres) and “Bipolaris spot blotch” (Bipolaris sorokiniana) are foliar diseases of barley. Biological control is currently considered as an efficient alternative to chemical management of these plant diseases. The aim of the present study was to identify 2 isolates of Chaetomium (C2 and C5), endophytics on barley seedlings and to study the in vitro interactions with D. teres and B. sorokiniana, isolated from seeds of the same host. Cultural and morphological characterization of all microorganisms was done. In addition, molecular characterization of Chaetomium spp. was conducted and dual culture tests were carried out to find, by microscopic observations, the effects of the antagonist on the morphology of the pathogens. The results confirm the identity of the pathogens and the isolates of Chaetomium spp. as Chaetomium globosum species group. Inhibition of B. sorokiniana and D. teres by C2 and C5 accounted for 30% and 31.2 %, and 40% and 36% respectively, compared with the control. The mechanisms of action against B. sorokiniana and D. teres were antibiosis and competition and mycoparasitism, respectively. Microscopic observation revealed deformed conidia in B. sorokiniana and plasmolisis, coiling and orange pigmentation in D. teres.Centro de Investigaciones en Fitopatologí

    Antagonism and modes of action of Chaetomium globosum species group, potential biocontrol agent of barley foliar diseases

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    Antagonismo y mecanismos de acción de hongos del grupo de especies Chaetomium globosum, potenciales biocontroladores de enfermedades fúngicas foliares de la cebada. La “mancha en red y la “mancha borrosa” son enfermedades foliares de cebada causadas por Drechslera teres y Bipolaris sorokiniana, respectivamente. Una alternativa para su manejo es el control biológico. El objetivo de este trabajo fue identificar dos aislamientos del género Chaetomium (C2 y C5), endofíticos de plántulas de cebada y estudiar sus interacciónes in vitro con D. teres y B. sorokiniana, aisladas de semillas del mismo hospedante. Todos los microorganismos se caracterizaron cultural y morfológicamente. Los aislamientos de Chaetomium además se caracterizaron molecularmente. Se realizaron pruebas de cultivos duales y se registraron los efectos del antagonista a nivel microscópico en la morfología de los patógenos. Los resultados confirmaron la identidad de los patógenos y de los aislamientos de Chaetomium spp. como Chaetomium globosum grupo de especies. Bipolaris sorokiniana fue inhibida en un 30% por C2 y en un 31.2 % por C5 respecto al control. D.teres fue inhibida en un 40% por C2 y en un 36% por C5 en referencia al control. Los mecanismos de acción frente a B. sorokiniana fueron antibiosis y competencia. Microscopicamente se observaron conidios aberrantes. Frente a D. teres se registró competencia y micoparasitismo. Microscópicamente se evidenció plasmólisis, enrollamiento y pigmentación anaranjada.“Net blotch” (Drechslera teres) and “Bipolaris spot blotch” (Bipolaris sorokiniana) are foliar diseases of barley. Biological control is currently considered as an efficient alternative to chemical management of these plant diseases. The aim of the present study was to identify 2 isolates of Chaetomium (C2 and C5), endophytics on barley seedlings and to study the in vitro interactions with D. teres and B. sorokiniana, isolated from seeds of the same host. Cultural and morphological characterization of all microorganisms was done. In addition, molecular characterization of Chaetomium spp. was conducted and dual culture tests were carried out to find, by microscopic observations, the effects of the antagonist on the morphology of the pathogens. The results confirm the identity of the pathogens and the isolates of Chaetomium spp. as Chaetomium globosum species group. Inhibition of B. sorokiniana and D. teres by C2 and C5 accounted for 30% and 31.2 %, and 40% and 36% respectively, compared with the control. The mechanisms of action against B. sorokiniana and D. teres were antibiosis and competition and mycoparasitism, respectively. Microscopic observation revealed deformed conidia in B. sorokiniana and plasmolisis, coiling and orange pigmentation in D. teres.Centro de Investigaciones en Fitopatologí

    Comparación a campo de distintos cultivares de olivo (Olea europaea L.) como hospedadores de Siphoninus phillyreae (Haliday)*

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    The ash whitefly, Siphoninus phillyreae (Haliday) is an invasive polyphagous species that causes serious damage to their hosts, including olive (Olea europaea L.). Host use by S. phillyreae was observed in three olive cultivars (Arauco, Arbequina y Aloreña) in North of La Rioja province (Argentina) during 2007 and 2008. Eight leaves of six infested plants of each cultivar were sampled. Adults and inmature stages abundances of each leaf were recorded. These abundances per cultivar were compared using general linear mixed model. The results showed significant differences between the densities of adults and nymphs of S. phillyreae in each of the olive cultivars analyzed. Thus, our results indicate that this insect makes a different use of the olive cultivars, Arauco and Arbequina being the most used in the study area.  La mosca blanca del fresno, Siphoninus p h i l l y r e a e ( H a l i d a y ) , e s u n a e s p e c i e polífaga invasiva que causa graves daños en sus hospedadores, entre ellos el olivo (Olea europaea L.). El uso del hospedador por parte de S. phillyreae fue observado en tres cultivares de olivo (Arauco, Arbequina y Aloreña) en el norte de la provincia de La Rioja (Argentina) durante 2007 y 2008. De cada cultivar se muestrearon seis plantas infestadas y de cada planta se tomaron ocho hojas. De cada hoja se registró la abundancia de adultos y estados inmaduros de la mosca blanca que fueron comparadas entre los cultivares mediante modelos lineales generales y mixtos. Los resultados obtenidos mostraron diferencias significativas entre las densidades de adultos y ninfas de S. phillyreae en los distintos cultivares de olivo analizados. Dichos resultados indican que este insecto realiza un uso diferente de los cultivares de olivo, siendo Arauco y Arbequina las variedades hospedadoras más utilizadas en la zona de estudio

    Musculoskeletal Features without Ataxia Associated with a Novel de novo Mutation in KCNA1 Impairing the Voltage Sensitivity of Kv1.1 Channel

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    The KCNA1 gene encodes the subunit of the voltage-gated Kv1.1 potassium channel that critically regulates neuronal excitability in the central and peripheral nervous systems. Mutations in KCNA1 have been classically associated with episodic ataxia type 1 (EA1), a movement disorder triggered by physical and emotional stress. Additional features variably reported in recent years include epilepsy, myokymia, migraine, paroxysmal dyskinesia, hyperthermia, hypomagnesemia, and cataplexy. Interestingly, a few individuals with neuromyotonia, either isolated or associated with skeletal deformities, have been reported carrying variants in the S2–S3 transmembrane segments of Kv1.1 channels in the absence of any other symptoms. Here, we have identified by whole-exome sequencing a novel de novo variant, T268K, in KCNA1 in a boy displaying recurrent episodes of neuromyotonia, muscle hypertrophy, and skeletal deformities. Through functional analysis in heterologous cells and structural modeling, we show that the mutation, located at the extracellular end of the S3 helix, causes deleterious effects, disrupting Kv1.1 function by altering the voltage dependence of activation and kinetics of deactivation, likely due to abnormal interactions with the voltage sensor in the S4 segment. Our study supports previous evidence suggesting that specific residues within the S2 and S3 segments of Kv1.1 result in a distinctive phenotype with predominant musculoskeletal presentation

    Clinical and molecular consequences of exon 78 deletion in DMD gene

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    We present a 13-year-old patient with persistent increase of serum Creatine Kinase (CK) and myalgia after exertion. Skeletal muscle biopsy showed marked reduction of dystrophin expression leading to genetic analysis of DMD gene by MLPA, which detected a single deletion of exon 78. To the best of our knowledge, DMD exon 78 deletion has never been described in literature and, according to prediction, it should lead to loss of reading frame in the dystrophin gene. To further assess the actual effect of exon 78 deletion, we analysed cDNA from muscle mRNA. This analysis confirmed the absence of 32 bp of exon 78. Exclusion of exon 78 changes the open reading frame of exon 79 and generate a downstream stop codon, producing a dystrophin protein of 3703 amino acids instead of 3685 amino acids. Albeit loss of reading frame usually leads to protein degradation and severe phenotype, in this case, we demonstrated that deletion of DMD exon 78 can be associated with a functional protein able to bind DGC complex and a very mild phenotype. This study adds a novel deletion in DMD gene in human and helps to define the compliance between maintaining/disrupting the reading frame and clinical form of the disease

    The SPTLC1 p.S331 mutation bridges sensory neuropathy and motor neuron disease and has implications for treatment

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    Aims SPTLC1-related disorder is a late onset sensory-autonomic neuropathy associated with perturbed sphingolipid homeostasis which can be improved by supplementation with the serine palmitoyl-CoA transferase (SPT) substrate, l-serine. Recently, a juvenile form of motor neuron disease has been linked to SPTLC1 variants. Variants affecting the p.S331 residue of SPTLC1 cause a distinct phenotype, whose pathogenic basis has not been established. This study aims to define the neuropathological and biochemical consequences of the SPTLC1 p.S331 variant, and test response to l-serine in this specific genotype. Methods We report clinical and neurophysiological characterisation of two unrelated children carrying distinct p.S331 SPTLC1 variants. The neuropathology was investigated by analysis of sural nerve and skin innervation. To clarify the biochemical consequences of the p.S331 variant, we performed sphingolipidomic profiling of serum and skin fibroblasts. We also tested the effect of l-serine supplementation in skin fibroblasts of patients with p.S331 mutations. Results In both patients, we recognised an early onset phenotype with prevalent progressive motor neuron disease. Neuropathology showed severe damage to the sensory and autonomic systems. Sphingolipidomic analysis showed the coexistence of neurotoxic deoxy-sphingolipids with an excess of canonical products of the SPT enzyme. l-serine supplementation in patient fibroblasts reduced production of toxic 1-deoxysphingolipids but further increased the overproduction of sphingolipids. Conclusions Our findings suggest that p.S331 SPTLC1 variants lead to an overlap phenotype combining features of sensory and motor neuropathies, thus proposing a continuum in the spectrum of SPTLC1-related disorders. l-serine supplementation in these patients may be detrimental

    Reliability of the Performance of Upper Limb assessment in Duchenne muscular dystrophy

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    Abstract The Performance of Upper Limb was specifically designed to assess upper limb function in Duchenne muscular dystrophy. The aim of this study was to assess (1) a cohort of typically developing children from the age of 3 years onwards in order to identify the age when the activities assessed in the individual items are consistently achieved, and (2) a cohort of 322 Duchenne children and young adults to establish the range of findings at different ages. We collected normative data for the scale validation on 277 typically developing subjects from 3 to 25 years old. A full score was consistently achieved by the age of 5 years. In the Duchenne cohort there was early involvement of the proximal muscles and a proximal to distal progressive involvement. The scale was capable of measuring small distal movements, related to activities of daily living, even in the oldest and weakest patients. Our data suggest that the assessment can be reliably used in both ambulant and non ambulant Duchenne patients in a multicentric setting and could therefore be considered as an outcome measure for future trials

    The effect of landscape structure on two species of different trophic levels in an arid environment

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    Insect species of different trophic level will respond differently to landscape configuration. Objective: In this context we explore the way landscape structure affects the distribution and abundance of the whitefly Siphoninus phillyreae and its predator Clitostethus arcuatus in olive orchards. Methods: Adult individuals of these two species were collected using sticky traps placed in 12 olive host patches in Argentina. Host patches were detected and quantified using Landsat 5 TM images. Different landscape metrics were estimated for the study area land covers. PLSR analysis techniques were employed to relate the mean abundance of the studied species and the landscape measures. Results: The Landsat land use estimations showed that most of the vegetation is limited to particular irrigated spots or urban areas. 89 % of the land cover is exposed soil, 10 % is xerophytic vegetation, 0.56 % is introduced urban vegetation and 0.31 % is occupied by olive orchards. S. phillyreae was positively affected by total area of olive orchards, followed by total area of urban vegetation, and negatively affected by the perimeter of olive focal patch and the proximity of other urban vegetation patches. C. arcuatus was positively affected by the perimeter of the host patch, the total area of olive orchards and the mean proximity of urban vegetation patches. Conclusion: We concluded that although the total area of the herbivore host was the most influential variable affecting the two species, each of them was affected in different way by other landscape elements.Fil: Grilli, Mariano Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinar de Biología Vegetal (P). Grupo Vinculado Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales; ArgentinaFil: Pedemonte, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinar de Biología Vegetal (P). Grupo Vinculado Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales; ArgentinaFil: Bruno, Marina Anabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinar de Biología Vegetal (P). Grupo Vinculado Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales; ArgentinaFil: Fachinetti, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinar de Biología Vegetal (P). Grupo Vinculado Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales; Argentin
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