Evaluation of different physical treatments in minimally processed green and red pepper (Capsicum annuum L.)

This work evaluates three different conservation methods for red and green fresh-cut peppers. Red and green fruit were processed into sticks and treated as follows: A) water batch immersion (45 oC, 3 min) (TT), B) UV-C radiation (20 kJ m-2) or C) modified atmosphere storage (AM). Other group of pepper sticks were left untreated (control). The sticks were stored at 5 oC during 12 d. Fruit decay, soft-rot and respiratory rate were evaluated during storage. The three treatments were effective to reduce sticks deterioration and the treated fruit evidenced lower respiratory rate at 7 d of storage with respect to control. While the three methods were beneficial to maintain quality, in the red sticks the best results were found with TT and UV, mainly because the AM had less control of the soft-rot at the end of storage. In green sticks all the treatments were equally effective

Recent emergence and worldwide spread of the red tomato spider mite, [i]Tetranychus evansi[/i]: genetic variation and multiple cryptic invasions

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699Plant biosecurity is increasingly challenged by emerging crop pests. The spider mite Tetranychus evansi has recently emerged as a new threat to solanaceous crops in Africa and the Mediterranean basin, with invasions characterized by a high reproductive output and an ability to withstand a wide range of temperatures. Mitochondrial (868 bp of COI) and nuclear (1,137 bp of ITS) loci were analyzed in T. evansi samples spanning the current geographical distribution to study the earliest stages of the invasive process. The two sets of markers separate the samples into two main clades that are only present together in South America and Southern Europe. The highest COI diversity was found in South America, consistent with the hypothesis of a South American origin of T. evansi. Among the invaded areas, the Mediterranean region displayed a high level of genetic diversity similar to that present in South America, that is likely the result of multiple colonization events. The invasions of Africa and Asia by T. evansi are characterized by a low genetic variation associated with distinct introductions. Genetic data demonstrate two different patterns of invasions: (1) populations in the Mediterranean basin that are a result of multiple cryptic introductions and (2) emerging invasions of Africa and Asia, each likely the result of propagules from one or limited sources. The recent invasions of T. evansi illustrate not only the importance of human activities in the spread of agricultural pests, but also the limits of international quarantine procedures, particularly for cryptic invasion

A diagnostic LAMP assay for rapid identification of an invasive plant pest, fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae)

Fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), is a highly polyphagous invasive plant pest that has expanded its global geographic distribution, including recently into much of Australia. Rapid diagnostic tests are required for identification of FAW to assist subsequent management and control. We developed a new loop-mediated isothermal amplification (LAMP) assay based on the mitochondrial cytochrome c oxidase subunit I (COI) gene for accurate and timely diagnosis of FAW in the field. The specificity of the new assay was tested against a broad panel of twenty non-target noctuids, including eight other Spodoptera species. Only S. frugiperda samples produced amplification within 20 min, with an anneal derivative temperature of 78.3 ± 0.3 °C. A gBlock dsDNA fragment was developed and trialled as a synthetic positive control, with a different anneal derivative of 81 °C. The new FAW LAMP assay was able to detect FAW DNA down to 2.4 pg, similar to an existing laboratory-based real-time PCR assay. We also trialled the new FAW assay with a colorimetric master mix and found it could successfully amplify positive FAW samples in half the time compared to an existing FAW colorimetric LAMP assay. Given the high sensitivity and rapid amplification time, we recommend the use of this newly developed FAW LAMP assay in a portable real-time fluorometer for in-field diagnosis of FAW

Efecto del quitosano y luz azul en la sanidad de zanahoria mínimamente procesada

Se ha demostrado que el quitosano, biopolímero derivado de la quitina, posee propiedades antimicrobianas y puede formar recubrimientos comestibles. Algunos autores han descrito su efecto elicitor de respuestas de defensa en vegetales. Por otro lado, el desarrollo de la tecnología LED permite el empleo de la luz visible como estrategia no contaminante para mejorar la conservación de productos frescos y de IV-gama.  Por esta razón se determinó el efecto combinado de quitosano y luz azul sobre la conservación de zanahoria mínimamente procesada.  Las zanahorias cultivar Chantenay fueron lavadas, peladas y cortadas en discos de 0,5 cm de espesor. Cuatro grupos de discos fueron sometidos a los siguientes tratamientos: quitosano (inmersión en solución al 1% por 2 minutos), luz (LED azul 14, 12 W/m2, 7 minutos en ambas caras del disco), quitosano+luz, y control. Los discos se colocaron en bandejas plásticas cerradas con film plástico perforado (30 discos por bandeja, 5 bandejas por tratamiento) y almacenadas a 6°C y 98% HR. A los 0, 7, 14 y 21 días se determinó porcentaje de discos con podredumbre, recuento en placa de bacterias aeróbicas mesófilas (logUFC/g) y recuento en placa de mohos y levaduras (logUFC/g). Los datos se sometieron a ANAVA y test de Tukey para la comparación de medias (P<0,05). El porcentaje de discos con podredumbre fue de 0% en todos los tratamientos a los 0 y 7 días. A los 14 días el tratamiento con quitosano tuvo un 9,3% de podredumbres, diferenciándose por encima del resto de los tratamientos (quitosano+luz 4,7%; control 1,3%; luz 1,3%). A los 21 días, la podredumbre ascendió a ~35% en todos los tratamientos con excepción del tratamiento con luz, que presentó solo 1,3%. Todas las podredumbres fueron causadas por Alternaria ssp. En cuanto al recuento en placa de bacterias, fue menor en los tratamientos quitosano y quitosano+luz (0 y 1,9 logUFC/g) a los 0 días (control 4,63 y luz 4,67 logUFC/g). A los 7 días el tratamiento quitosano aumentó el número de bacterias (6,37 logUFC/g) con respecto al resto (control 5,83; luz 5,63; y quitosano+luz 4,9 logUFC/g), y a los 14 días el tratamiento luz mostró los menores recuentos (5,93 logUFC/g) entre todos los tratamientos (control 6,40, quitosano + luz 6,60, quitosano 7,07 logUFC/g). A los 21 días la tendencia fue similar (luz 6,2; control 6,87; quitosano+luz 6,87; quitosano 7,5 logUFC/g). El número de mohos y levaduras determinados en el recuento en placa siguió similar patrón, y mostró las mismas diferencias significativas entre tratamientos a los 0 y 21 días. Los resultados sugieren que las tecnologías evaluadas tienen potencial para mejorar algunos aspectos de la conservación de zanahoria de IV-gama, destacando el efecto del quitosano y la luz azul, para períodos cortos y largos de almacenamiento, respectivamente. En futuros ensayos se evaluarán parámetros de calidad organoléptica

Efecto de la liofilización en la retención de antocianinas de los frutos de calafate (Berberis microphylla G. Forst.) y su incorporación en cerveza

Los frutos de calafate son extremadamente ricos en compuestos antioxidantes, principalmente antocianinas. El objetivo fue evaluar la influencia de la liofilización sobre el contenido de antocianinas en los calafates durante el almacenamiento. Un grupo de frutos fue analizado inmediatamente y los restantes fueron sometidos a congelado a -80 ºC y liofilización. Por otra parte, a cerveza comercial tipo block se le adicionó 1,0; 2,5; 5,0 o 20 g L-1 de frutos liofilizados y pulverizados. Los frutos frescos tuvieron 35 mg g-1 de antocianinas y la liofilización redujo su contenido en 7 %. El contenido de antocianinas se mantuvo sin variaciones por 21 y 45 días respectivamente. Hacia los 60 días el contenido de antocianinas de los frutos liofilizados representó el 67% del contenido inicial. El pH de la cerveza fue de 4,34 y no varió con el agregado de polvo de calafate hasta 5 g L-1. En el caso de las cervezas con el agregado de 20 g L-1 el pH descendió a 4,00. El agregado de calafate provocó un cambio en el color de la cerveza debido a su aporte de antocianinas, y este cambio en el color fue función de la cantidad de fruto adicionado. La absorbancia a 520 nm fue de 0,230; 0,254; 0,291; 0,353 y 0,644 para la cerveza sin agregado o con 1,0; 2,5; 5,0 o 20 g L-1 de calafate  espectivamente. Solo cantidades mayores a 2,5 g L-1 de polvo adicionado provocaron un incremento de actividad antioxidante, llegando al 30 % con la adición de 20 g L-1. La liofilización es una estrategia adecuada para preservar las antocianinas de los frutos de calafate sin alteraciones por 45 días. Dependiendo de la cantidad adicionada, el calafate provoca en la cerveza cambio de color y descenso del pH que puede ser de utilidad en cervezas especiales

Validation of Genotyping by Sequencing Using Transcriptomics for Diversity and Application of Genomic Selection in Tetraploid Potato

Potato is an important food crop due to its increasing consumption, and as a result, there is demand for varieties with improved production. However, the current status of breeding for improved varieties is a long process which relies heavily on phenotypic evaluation and dated molecular techniques and has little emphasis on modern genotyping approaches. Evaluation and selection before a cultivar is commercialized typically takes 10–15 years. Molecular markers have been developed for disease and pest resistance, resulting in initial marker-assisted selection in breeding. This study has evaluated and implemented a high-throughput transcriptome sequencing method for dense marker discovery in potato for the application of genomic selection. An Australian relevant collection of commercial cultivars was selected, and identification and distribution of high quality SNPs were examined using standard bioinformatic pipelines and a custom approach for the prediction of allelic dosage. As a result, a large number of SNP markers were identified and filtered to generate a high-quality subset that was then combined with historic phenotypic data to assess the approach for genomic selection. Genomic selection potential was predicted for highly heritable traits and the approach demonstrated advantages over the previously used technologies in terms of markers identified as well as costs incurred. The high-quality SNP list also provided acceptable genome coverage which demonstrates its applicability for much larger future studies. This SNP list was also annotated to provide an indication of function and will serve as a resource for the community in future studies. Genome wide marker tools will provide significant benefits for potato breeding efforts and the application of genomic selection will greatly enhance genetic progress

Metabolic rate and rates of protein turnover in food-deprived cuttlefish, Sepia officinalis (Linnaeus 1758)

To determine the metabolic response to food deprivation, cuttlefish (Sepia officinalis) juveniles were either fed, fasted (3 to 5 days food deprivation), or starved (12 days food deprivation). Fasting resulted in a decrease in triglyceride levels in the digestive gland, and after 12 days, these lipid reserves were essentially depleted. Oxygen consumption was decreased to 53% and NH4 excretion to 36% of the fed group following 3-5 days of food deprivation. Oxygen consumption remained low in the starved group, but NH4 excretion returned to the level recorded for fed animals during starvation. The fractional rate of protein synthesis of fasting animals decreased to 25% in both mantle and gill compared with fed animals and remained low in the mantle with the onset of starvation. In gill, however, protein synthesis rate increased to a level that was 45% of the fed group during starvation. In mantle, starvation led to an increase in cathepsin A-, B-, H-, and L-like enzyme activity and a 2.3-fold increase in polyubiquitin mRNA that suggested an increase in ubiquitin-proteasome activity. In gill, there was a transient increase in the polyubiquitin transcript levels in the transition from fed through fasted to the starved state and cathepsin A-, B-, H-, and L-like activity was lower in starved compared with fed animals. The response in gill appears more complex, as they better maintain rates of protein synthesis and show no evidence of enhanced protein breakdown through recognized catabolic processes

Tecnología de la elaboración de quesos: experiencias de investigación aplicada y capacitación para estudiantes, técnicos, pequeños productores y la comunidad en general

Con un volumen de unos 11.300 millones de litros anuales, la Argentina es el segundo productor de leche de Latinoamérica, luego de Brasil. Los quesos constituyen el destino industrial más importante de la leche en nuestro país. Con los objetivos de 1) difundir los aspectos más salientes de los procesos de transformación de leche en productos elaborados para el público en general y 2) realizar aportes en la mejora de los procesos de producción de quesos para pequeños productores y técnicos del sector, hemos venido realizando en los últimos años diferentes actividades desde el Laboratorio de Investigación en Productos Agroindustriales (LIPA) de la Facultad de Ciencias Agrarias y Forestales de la Universidad Nacional de La Plata. Así, se organizaron talleres y cursos de capacitación para diferentes grupos: a) alumnos de educación inicial interesados en conocer los fundamentos del proceso de transformación de leche en queso, b) estudiantes de colegios secundarios agropecuarios con interés en profundizar en aspectos de calidad e industrialización de leche, c) estudiantes de la carrera de biotecnología de la UNLP con curiosidad por conocer cómo herramientas de interés desarrolladas biotecnológicamente (cuajo, cultivos iniciadores) son empleadas en la industria, d) pequeños productores y técnicos con interés de mejorar sus productos y servicios. Asimismo, en el laboratorio se llevan adelante investigaciones aplicadas tendientes a determinar la influencia de factores de proceso sobre la calidad y estabilidad de quesos. Algunos de los aspectos analizados incluyen la influencia del nivel de grasa de la leche sobre la calidad sensorial, composición de quesos, la optimización de la obtención de ricota a partir de leche, la influencia de la intensidad de lavado de la masa sobre las propiedades funcionales de queso cremoso. La combinación de investigación aplicada y actividades de capacitación y divulgación resulta una estrategia indispensable para poder transferir los conocimientos disponibles en las instituciones universitarias al medio así como para retroalimentar a la universidad con problemáticas reales y los saberes del sector productivo

Enzymatic capacities of metabolic fuel use in cuttlefish (Sepia officinalis) and responses to food deprivation: insight into the metabolic organization and starvation survival strategy of cephalopods

Food limitation is a common challenge for animals. Cephalopods are sensitive to starvation because of high metabolic rates and growth rates related to their "live fast, die young" life history. We investigated how enzymatic capacities of key metabolic pathways are modulated during starvation in the common cuttlefish (Sepia officinalis) to gain insight into the metabolic organization of cephalopods and their strategies for coping with food limitation. In particular, lipids have traditionally been considered unimportant fuels in cephalopods, yet, puzzlingly, many species (including cuttlefish) mobilize the lipid stores in their digestive gland during starvation. Using a comprehensive multi-tissue assay of enzymatic capacities for energy metabolism, we show that, during long-term starvation (12 days), glycolytic capacity for glucose use is decreased in cuttlefish tissues, while capacities for use of lipid-based fuels (fatty acids and ketone bodies) and amino acid fuels are retained or increased. Specifically, the capacity to use the ketone body acetoacetate as fuel is widespread across tissues and gill has a previously unrecognized capacity for fatty acid catabolism, albeit at low rates. The capacity for de novo glucose synthesis (gluconeogenesis), important for glucose homeostasis, likely is restricted to the digestive gland, contrary to previous reports of widespread gluconeogenesis among cephalopod tissues. Short-term starvation (3-5 days) had few effects on enzymatic capacities. Similar to vertebrates, lipid-based fuels, putatively mobilized from fat stores in the digestive gland, appear to be important energy sources for cephalopods, especially during starvation when glycolytic capacity is decreased perhaps to conserve available glucose