186 research outputs found

    Transcriptome and metabolome profiling identify factors potentially involved in pro-vitamin A accumulation in cassava landraces

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    Open Access ArticleCassava (Manihot esculenta Crantz) is a predominant food security crop in several developing countries. Its storage roots, rich in carbohydrate, are deficient in essential micronutrients, including provitamin A carotenoids. Increasing carotenoid content in cassava storage roots is important to reduce the incidence of vitamin A deficiency, a public health problem in sub-Saharan Africa. However, cassava improvement advances slowly, mainly due to limited information on the molecular factors influencing β-carotene accumulation in cassava. To address this problem, we performed comparative transcriptomic and untargeted metabolic analyses of roots and leaves of eleven African cassava landraces ranging from white to deep yellow colour, to uncover regulators of carotenoid biosynthesis and accumulation with conserved function in yellow cassava roots. Sequence analysis confirmed the presence of a mutation, known to influence β-carotene content, in PSY transcripts of deep yellow but not of pale yellow genotypes. We identified genes and metabolites with expression and accumulation levels significantly associated with β-carotene content. Particularly an increased activity of the abscisic acid catabolism pathway together with a reduced amount of L-carnitine, may be related to the carotenoid pathway flux, higher in yellow than in white storage roots. In fact, NCED_3.1 was specifically expressed at a lower level in all yellow genotypes suggesting that it could be a potential target for increasing carotenoid accumulation in cassava. These results expand the knowledge on metabolite compositions and molecular mechanisms influencing carotenoid biosynthesis and accumulation in cassava and provide novel information for biotechnological applications and genetic improvement of cassava with high nutritional values

    Situational diagnostic of the breeding of guinea pigs in Cajamarca

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    Se realizó una encuesta en julio de 2004 a 160 familias criadoras de cuyes en el distrito de Santa Cruz, Cajamarca, con el objetivo de caracterizar los sistemas de producción de cuyes. El 44.6% de los productores tenía más de 50 años de edad y el 42% de las esposas tenía entre 31 a 50 años. Primaria era el grado de instrucción predominante. La ocupación del jefe de familia era la agricultura (95.4%) y de la esposa era su casa (97.2%). La crianza de cuyes era conducida por el ama de casa bajo un sistema familiar o tradicional. Se encontró un promedio de 20.4 cuyes por familia, criados en un solo grupo sin distinción de clase, sexo y edad, de preferencia en la cocina (88.8%), donde permanecían sueltos (73.8%) o en pozas (21.9%). La alimentación se basó en forrajes, malezas y residuos de cocina. Las principales enfermedades reportadas fueron ectoparásitos (90.1%) y la “peste” (76%). El 71.2% de las familias destinaba los cuyes para autoconsumo y venta, y el 28.2% sólo para autoconsumo. El 96.2% de los encuestados no disponía de servicios de asistencia técnica, créditos, insumos, etc. El 67.5% de los criadores consideraba que mejorarían su crianza con asistencia técnica.A survey was conducted in July 2004 to 160 families rearing Guinea pigs in the district of Santa Cruz, Cajamarca, with the aim of characterizing the production system of these animals. Men were more than 50 years of age (44.6%) and wives were mainly between 31 to 50 years old (42%). Primary school was the main grade of instruction. The main labour activity of the head of the family was agriculture (95.4%) and housekeeping for women (97.2%). Raising guinea pigs was mainly driven by the housewife under a family or traditional system. There were 20.4 guinea pigs on average per family, reared regardless of class, sex and age, preferably in the kitchen (88.8%), free (73.8%) or in pools (21.9%). Feeding was based on forages, weeds and kitchen waste. The main diseases reported were ectoparasites (90.1%) and the «plague» (76%). Guinea pigs were used for consumption and sale (71.2%) or only for home consumption (28.2%). Most of producers (96.2%) indicated that they do not have services such as technical assistance, credit, inputs, etc, and 67.5% considered that they would improve their productivity if technical assistance was available

    Expression of symptoms elicited by a hammerhead viroid through RNA silencing is related to population bottlenecks in the infected host

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    Open Access ArticleChlorosis is frequently incited by viroids, small nonprotein-coding, circular RNAs replicating in nuclei (family Pospiviroidae) or chloroplasts (family Avsunviroidae). Here, we investigated how chrysanthemum chlorotic mottle viroid (CChMVd, Avsunviroidae) colonizes, evolves and initiates disease. Progeny variants of natural and mutated CChMVd sequence variants inoculated in chrysanthemum plants were characterized, and plant responses were assessed by molecular assays. We showed that: chlorotic mottle induced by CChMVd reflects the spatial distribution and evolutionary behaviour in the infected host of pathogenic (containing a UUUC tetranucleotide) and nonpathogenic (lacking such a pathogenic determinant) variants; and RNA silencing is involved in the initiation of the chlorosis in symptomatic leaf sectors through a viroid derived small RNA containing the pathogenic determinant that directs AGO1-mediated cleavage of the mRNA encoding the chloroplastic transketolase. This study provides the first evidence that colonization of leaf tissues by CChMVd is characterized by segregating variant populations differing in pathogenicity and with the ability to colonize leaf sectors (bottlenecks) and exclude other variants (superinfection exclusion). Importantly, no specific pathogenic viroid variants were found in the chlorotic spots caused by chrysanthemum stunt viroid (Pospiviroidae), thus establishing a clear distinction on how members of the two viroid families trigger chlorosis in the same host

    Massive X-ray screening reveals two allosteric drug binding sites of SARS-CoV-2 main protease

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    The coronavirus disease (COVID-19) caused by SARS-CoV-2 is creating tremendous health problems and economical challenges for mankind. To date, no effective drug is available to directly treat the disease and prevent virus spreading. In a search for a drug against COVID-19, we have performed a massive X-ray crystallographic screen of repurposing drug libraries containing 5953 individual compounds against the SARS-CoV-2 main protease (Mpro), which is a potent drug target as it is essential for the virus replication. In contrast to commonly applied X-ray fragment screening experiments with molecules of low complexity, our screen tested already approved drugs and drugs in clinical trials. From the three-dimensional protein structures, we identified 37 compounds binding to Mpro. In subsequent cell-based viral reduction assays, one peptidomimetic and five non-peptidic compounds showed antiviral activity at non-toxic concentrations. Interestingly, two compounds bind outside the active site to the native dimer interface in close proximity to the S1 binding pocket. Another compound binds in a cleft between the catalytic and dimerization domain of Mpro. Neither binding site is related to the enzymatic active site and both represent attractive targets for drug development against SARS-CoV-2. This X-ray screening approach thus has the potential to help deliver an approved drug on an accelerated time-scale for this and future pandemics

    Meristemas: fontes de juventude e plasticidade no desenvolvimento vegetal

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    La théologie face aux sciences religieuses. Différences et interactions

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    Engouement pour le bouddhisme, redécouverte de la mystique, attrait des religions non monothéistes ou essor des sectes, voici quelques-uns des symptômes d'une nouvelle interrogation de l'Occident sur lui-même. Comment situer aujourd'hui la théologie chrétienne face à cela? Y a-t-il complémentarité? Hiérarchie? Antagonisme? C'est à ces questions que répond Pierre Gisel dans un livre prospectif qui servira à mieux identifier les défis et les mutations religieuses dans l'effervescence actuelle
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