In vitro induction of functional allergen-specific CD4+ CD25high Treg cells in horses affected with insect bite hypersensitivity

BACKGROUND Insect bite hypersensitivity (IBH) is a recurrent allergic dermatitis of horses with similarities to human atopic eczema, caused by bites of insects of the genus Culicoides. Previous studies suggested a dysregulated T cell tolerance to Culicoides allergen in IBH-affected horses. OBJECTIVE We have investigated whether the suppressive function of CD4(+) CD25(high) cells is impaired in IBH-affected horses and possible ways to restore it. METHODS CD4(+) CD25(-) cells sorted from peripheral blood mononuclear cells (PBMC) were stimulated with irradiated autologous PBMC pulsed with Culicoides or tetanus toxoid as control antigen, in the presence of CD4(+) CD25(high) cells. Furthermore, Culicoides-specific CD4(+) CD25(high) regulatory cells were expanded or induced from CD4(+) CD25(-) cells in vitro in the presence of a combination of rIL-2 and rTGF-β1 (rIL-2/rTGF-β1) or of retinoic acid and rapamycin (RetA/Rapa). Proliferation was determined by [(3) H] thymidine incorporation and cytokine production measured by flow cytometry. RESULTS The ability of Culicoides- but not tetanus-stimulated CD4(+) CD25(high) cells to suppress proliferation of CD4(+) CD25(-) cells was significantly lower in IBH-affected horses (28%) than in healthy controls (86%). The decreased suppression in IBH-affected horses was associated with a significantly higher proportion of IL-4(+) cells and a lower percentage of FoxP3(+) IL-10(+) compared to controls. Addition of rIL-2/rTGF-β1 or of RetA/Rapa to Culicoides-stimulated CD4(+) CD25(high) cells from IBH-affected horses significantly increased the proportion of FoxP3(+) IL-10(+) cells. We also found that RetA/Rapa induced a more significant decrease in the frequency of IL-4(+) cells than rIL-2/rTGF-β1. Moreover, the suppressive activity of Culicoides-stimulated CD4(+) CD25(high) cells was significantly restored by both rIL-2/rTGF-β1and RetA/Rapa, albeit in an antigen-unspecific manner. In contrast, in vitro induced Culicoides-specific CD4(+) CD25(high) cells suppressed proliferation of CD4(+) CD25(-) cells in an antigen-specific manner. CONCLUSION AND CLINICAL RELEVANCE The in vitro induction of functional allergen-specific Treg cells in IBH-affected horses suggests a potential therapeutic use of these cells in allergy.

Carbon sequestration in community forests: trade-offs, multiple outcomes and institutional diversity in the Bolivian Amazon

Carbon sequestration in community forests presents a major challenge for the Reducing Emissions from Deforestation and Forest Degradation (REDD+) programme. This article uses a comparative analysis of the agricultural and forestry practices of indigenous peoples and settlers in the Bolivian Amazon to show how community-level institutions regulate the trade-offs between community livelihoods, forest species diversity, and carbon sequestration. The authors argue that REDD+ implementation in such areas runs the risk of: 1) reinforcing economic inequalities based on previous and potential land use impacts on ecosystems (baseline), depending on the socio-cultural groups targeted; 2) increasing pressure on land used for food production, possibly reducing food security and redirecting labour towards scarce off-farm income opportunities; 3) increasing dependence on external funding and carbon market fluctuations instead of local production strategies; and 4) further incentivising the privatization and commodification of land to avoid transaction costs associated with collective property rights. The article also advises against taking a strictly economic, market-based approach to carbon sequestration, arguing that such an approach could endanger fragile socio-ecological systems. REDD+ schemes should directly support existing efforts towards forest sustainability rather than simply compensating local land users for avoiding deforestation and forest degradation

Isolation and functional characterization of a high affinity urea transporter from roots of Zea mays

Background: Despite its extensive use as a nitrogen fertilizer, the role of urea as a directly accessible nitrogen source for crop plants is still poorly understood. So far, the physiological and molecular aspects of urea acquisition have been investigated only in few plant species highlighting the importance of a high-affinity transport system. With respect to maize, a worldwide-cultivated crop requiring high amounts of nitrogen fertilizer, the mechanisms involved in the transport of urea have not yet been identified. The aim of the present work was to characterize the high-affinity urea transport system in maize roots and to identify the high affinity urea transporter. Results: Kinetic characterization of urea uptake (<300 mu M) demonstrated the presence in maize roots of a high-affinity and saturable transport system; this system is inducible by urea itself showing higher Vmax and Km upon induction. At molecular level, the ORF sequence coding for the urea transporter, ZmDUR3, was isolated and functionally characterized using different heterologous systems: a dur3 yeast mutant strain, tobacco protoplasts and a dur3 Arabidopsis mutant. The expression of the isolated sequence, ZmDUR3-ORF, in dur3 yeast mutant demonstrated the ability of the encoded protein to mediate urea uptake into cells. The subcellular targeting of DUR3/GFP fusion proteins in tobacco protoplasts gave results comparable to the localization of the orthologous transporters of Arabidopsis and rice, suggesting a partial localization at the plasma membrane. Moreover, the overexpression of ZmDUR3 in the atdur3-3 Arabidopsis mutant showed to complement the phenotype, since different ZmDUR3-overexpressing lines showed either comparable or enhanced 15N]-urea influx than wild-type plants. These data provide a clear evidence in planta for a role of ZmDUR3 in urea acquisition from an extra-radical solution. Conclusions: This work highlights the capability of maize plants to take up urea via an inducible and high-affinity transport system. ZmDUR3 is a high-affinity urea transporter mediating the uptake of this molecule into roots. Data may provide a key to better understand the mechanisms involved in urea acquisition and contribute to deepen the knowledge on the overall nitrogen-use efficiency in crop plants.

Characterization of the gene for an immunodominant 72 kDa lipoprotein of Mycoplasma mycoides subsp. mycoides small colony type.

With the aim of characterizing specific immunogenic proteins of Mycoplasma mycoides subsp. mycoides small colony (SC) type, the aetiological agent of contagious bovine pleuropneumonia, a gene encoding a major immunogenic protein of 72 kDa named P72 was cloned and expressed in Escherichia coli. The expressed protein was of the same apparent molecular mass as that produced by the parent strain. The predicted molecular mass of P72, based on the DNA-deduced amino acid sequence, was 61.118 kDa, significantly lower than the apparent molecular mass of endogenous or recombinant P72 on SDS-PAGE. Analysis of the amino acid sequence revealed a typical prokaryotic signal peptidase II-membrane lipoprotein lipid attachment site and a transmembrane structure domain in the leader sequence at the amino-terminal end of the protein. P72 was shown to be a lipoprotein and its surface location was confirmed by trypsin treatment of whole cells. An unassigned gene encoding a peptide with some similarity to P72 was found on the genome sequence of M. capricolum subsp. capricolum but not on that of Mycoplasma genitalium. The P72 gene was detected in 11/11 M. mycoides subsp. mycoides SC strains. Antiserum against recombinant P72 reacted strongly with 12/12 strains of M. mycoides subsp. mycoides SC, weakly with Mycoplasma bovine group 7 strain PG50, but not with other members of the 'mycoides cluster' or closely related mycoplasmas. Cows experimentally contact-infected with M. mycoides subsp. mycoides SC developed a humoral response against P72 within 35 d. P72 is a specific antigenic membrane lipoprotein of M. mycoides subsp. mycoides SC with potential for use in development of diagnostic reagents. It seems to belong to a family of lipoproteins of the "mycoides cluster'.

On the comparison of a novel serious game and electroencephalography biomarkers for early dementia screening

Patients with amnestic mild cognitive impairment are at high risk for developing Alzheimer's disease. Besides episodic memory dysfunction they show deficits in accessing contextual knowledge that further specifies a general spatial navigation task or an executive function (EF) virtual action planning. Virtual reality (VR) environments have already been successfully used in cognitive rehabilitation and show increased potential for use in neuropsychological evaluation allowing for greater ecological validity while being more engaging and user friendly. In our study we employed the in-house platform of virtual action planning museum (VAP-M) and a sample of 25 MCI and 25 controls, in order to investigate deficits in spatial navigation, prospective memory, and executive function. In addition, we used the morphology of late components in event-related potential (ERP) responses, as a marker for cognitive dysfunction. The related measurements were fed to a common classification scheme facilitating the direct comparison of both approaches. Our results indicate that both the VAP-M and ERP averages were able to differentiate between healthy elders and patients with amnestic mild cognitive impairment and agree with the findings of the virtual action planning supermarket (VAP-S). The sensitivity (specificity) was 100% (98%) for the VAP-M data and 87% (90%) for the ERP responses. Considering that ERPs have proven to advance the early detection and diagnosis of "presymptomatic AD," the suggested VAP-M platform appears as an appealing alternative.

Resilient Adaptation to Climate Change in African Agriculture

Africa’s agriculture faces varying climate change impacts which mainly worsen production conditions and adversely affect its economies. Adaptations thus need to build the resilience of farming systems. Using “resilient adaptation” as a concept, this study analyses how adaptations at farm and policy/institutional-levels contribute to the resilience of Sub-Saharan African agriculture. The developed tool, “the Resilience Check”, provides socio-economic data which complements existing adaptation tools. The underlying development gaps such as insecure property rights, poverty, low self-organisation, inadequate climate data and infrastructure limit resilient adaptations. If farmers could implement recommended practices, existing measures and improved crops can address most impacts expected in the medium-term. However, resource use efficiency remains critical for all farm management types. Development-oriented adaptation measures are needed to provide the robust foundations for building resilience. Reaching the very poor remains a challenge and the externally driven nature of many interventions raises concern about their sustainability. The study recommends practical measures such as decentralising various services and integrating the action plans of the multilateral environmental agreements into one national action plan.

A multi-level stakeholder approach to sustainable land management

Soils provide us with over 90% of all human food, livestock feed, fibre and fuel on Earth. Soils, however, have more than just productive functions. The key challenge in coming years will be to address the diverse and potentially conflicting demands now being made by human societies and other forms of life, while ensuring that future generations have the same potential to use soils and land of comparable quality. In a multi-level stakeholder approach, down-to-earth action will have to be supplemented with measures at various levels, from households to communities, and from national policies to international conventions. Knowledge systems, both indigenous and scientific, and related research and learning processes must play a central role. Ongoing action can be enhanced through a critical assessment of the impact of past achievements, and through better cooperation between people and institutions.

Kentucky Bluegrass Response to Potassium and Nitrogen Fertilization

The response of Kentucky bluegrass (Poa pratensis L.) to potassium (K) fertilization has been inconsistent. The objective of this research was to determine the effects of K fertilization across varying nitrogen (N) rates and clipping management on Kentucky bluegrass clipping yields, quality, tissue K concentrations, apparent N recovery, and N use efficiency. A 2 x 4 x 4 factorial was arranged in a splitplot design and repeated across two years. Main plots were clipping treatments (returned vs. removed) and subplots were N rates (0, 98, 196, and 294 kg ha(-1) yr(-1)) in combination with K rates (0, 81, 162, and 243 kg ha(-1) yr(-1)). There was no positive effect of K on clipping yields and quality even though soil extractable K levels tested low. Higher K rates, however, increased N recovery and use efficiency for all but the highest N rate. Tissue K response to K fertilization was nonlinear. Yield and quality responses were not correlated to tissue K concentration. Nonexchangeable K levels were high in the native soil, and may have provided an additional source of K for bluegrass. The results suggest that extractable K values alone may not adequately predict available K to Kentucky bluegrass in this sandy loam soil.

Clipping Management and Nitrogen Fertilization of Turfgrass: Growth, Nitrogen Utilization, and Quality

The effect of returning grass clippings on turfgrass growth and quality has not been thoroughly examined. The objective of this research was to determine the effects of returning grass clippings in combination with varying N rates on growth, N utilization, and quality of turfgrass managed as a residential lawn. Two field experiments using a cool-season turfgrass mixture were arranged as a 2 x 4 factorial in a randomized complete block design with three replicates. Treatments included two clipping management practices (returned or removed) and four N rates (equivalent to 0, 98, 196, and 392 kg N ha(-1)). Soils at the two sites were a Paxton fine sandy loam (coarse-loamy, mixed, active, mesic Oxyaquic Dystrudepts) and a variant of a Hinckley gravelly sandy loam (sandy-skeletal, mixed, mesic Typic Udorthents). Returning clippings was found to increase clipping dry matter yields (DMYs) from 30 to 72%, total N uptake (NUP) from 48 to 60%, N recovery by 62%, and N use efficiency (NUE) from 52 to 71%. Returning grass clippings did not decrease turfgrass quality, and improved it in some plots. We found that N fertilization rates could be reduced 50% or more without decreasing turfgrass quality when clippings were returned. Overall, returning grass clippings was found to improve growth and quality of turfgrass while reducing N fertilization needs.

Characterization of humoral immune responses against Treponema pallidum antigens

The spirochete Treponema pallidum subsp. pallidum is the causative agent of syphilis, a sexually transmitted disease with an estimated 12 million new cases per year worldwide. There is no vaccine currently available for the prevention of syphilis. In the present study, the T. pallidum hypothetical protein TP0693 was examined to determine its cellular location, and its potential for use as a vaccine candidate and immunodiagnostic for syphilis. TP0693 was demonstrated to be strongly reactive with sera from rabbits infected experimentally with T. pallidum for >25 days. Results from proteinase K digestion, immunofluorescence and immunoelectron microscopy were consistent with outer surface localization of TP0693. Serum reactivity against TP0693 was detected in only 68% of syphilis patients, which does not support its use as an immunodiagnostic for syphilis. Immunization of rabbits with TP0693 or three other outer membrane candidates did not alter the course of lesion development atter T. pallidum inoculation. We also examined the T. pallidum proteome by two-dimensional gel electrophoresis coupled with mass spectrometry analysis and immunoblotting. This approach resulted in the identification of 95 unique polypeptides, several of which were reactive with sera from infected rabbits and syphilis patients. The analyses described here enabled us to identify antigens potentially useful as vaccine candidates or diagnostic markers, and may provide insight into host-pathogen interactions during T. pallidum infection. ^

Producción de maíz bajo diferentes regímenes de riego complementario en Río Cuarto, Córdoba, Argentina. I. Rendimiento en grano de maíz y sus componentes

El maíz (Zea mays L.) es uno de los principales cultivos de la Pampa Húmeda de Argentina. El objetivo de este trabajo fue evaluar los efectos del riego complementario sobre el rendimiento de grano y sus componentes. El mismo se llevó a cabo en el ciclo agrícola 2001-2002, en el campo experimental de la Universidad Nacional de Río Cuarto. Se usó un diseño completamente al azar con 5 tratamientos y 4 repeticiones. Para efectuar la programación de los diferentes riegos se dividió el ciclo del cultivo en tres etapas: precrítico, crítico y poscrítico. Para la determinación del momento de riego se realizó un balance hídrico. El rendimiento de grano no mostró diferencias significativas en los cuatro tratamientos con riego, sin embargo, hubo diferencia significativa (α = 0,05) entre los tratamientos regados y no regados. En promedio el rendimiento en grano en los tratamientos regados fue de 72 % mayor que en el tratamiento sin riego. Los componentes del rendimiento fueron afectados significativamente (α = 0,05) por la falta de riego. La cantidad de agua aplicada varió entre 360 y 300 mm y el agua total consumida en el ciclo del cultivo (según el balance hídrico) fue para los tratamientos con riego, de 575 mm y para el testigo de 308 mm. La eficiencia del uso de agua para grano fue de 2.75 kg.m-3, en promedio.

Producción de maíz bajo diferentes regímenes de riego complementario en Río Cuarto, Córdoba, Argentina. II. Producción de materia seca

El objetivo de este trabajo fue evaluar el efecto del riego complementario sobre el rendimiento de materia seca del cultivo de maíz. Se usó un diseño completamente al azar con 5 tratamientos y 4 repeticiones. Para efectuar la programación de los diferentes tratamientos de riego se dividió el ciclo del cultivo en tres etapas (precrítico, crítico y poscrítico). Para la determinación del momento de riego se realizó un balance hídrico con datos climáticos obtenidos de la Estación Meteorológica ubicada en el lugar del ensayo. El riego se efectuó con un equipo presurizado de avance lateral. El maíz cumplió su ciclo en 138 días en todos los tratamientos y requirió 1660,6 grados día para alcanzar madurez fisiológica. El rendimiento de materia seca tuvo diferencias significativas (a = 0,05) entre los distintos tratamientos regados y entre éstos y el testigo. Los valores extremos de producción fueron de 34.628 kg.ha-1 en el tratamiento 1 y 20.414 kg.ha-1 en el tratamiento sin riego. La cantidad de agua aplicada varió entre 360 y 300 mm y el agua total consumida en el ciclo del cultivo, según el balance hídrico, fue para los tratamientos con riego de 575 mm ± 15 mm y para el testigo sin riego de 308 mm. La eficiencia de uso de agua para materia seca tuvo diferencias significativas (a = 0,05) entre los tratamientos regados (5,7 kg.m-3) y no regados (6,6 kg.m-3). El índice de cosecha fue de 0,49.

Uso de agua en las bodegas de Mendoza

El objetivo de este trabajo es conocer, a nivel de cuenca, el volumen de agua utilizado por las bodegas de Mendoza, el que se obtiene principalmente desde acuíferos. Dicha información puede ser utilizada para el cálculo del balance hídrico en el contexto del uso industrial del agua. Para realizar las estimaciones se utilizaron datos de elaboración de vino del Instituto Nacional de Vitivinicultura. A la producción de vino por cuenca se le aplicaron coeficientes de litros de agua utilizada por litros de vino elaborado, obtenidos de las entrevistas a informantes calificados y a partir de bibliografía local e internacional. Dichos coeficientes varían entre 1,5 y 6 litros de agua/litro de vino, los que no incluyen el uso de agua para riego en fincas. Para analizar el impacto en la eficiencia del uso del agua, los resultados se sensibilizaron para tres valores de coeficiente. Se estima que las bodegas de Mendoza utilizan entre 1,66 y 6,66 hm3/año, según sea la eficiencia del uso del agua. Del total de agua que utilizan, el 85,2% proviene de la cuenca norte, la que comprende el río Mendoza y el Tramo Inferior del Río Tunuyan.

Influencia de seis portainjertos de vid sobre el comportamiento vitícola de la cv. Malbec y estudio de las relaciones hídricas que se establecen

El uso de portainjertos en la vid se ha difundido por su resistencia a filoxera y nemátodos, pero también por su tolerancia a condiciones adversas del suelo. Por otro lado, los portainjertos modifican las relaciones fuente-destino, influyendo en el comportamiento vegetativo y reproductivo de las plantas y en la composición de la uva, lo cuál puede ser utilizado como una herramienta de manejo agronómico. A fin de evaluar si existe un comportamiento diferencial de los portainjertos en cuanto a expresión vegetativa, vigor, rendimiento y composición de la uva, y explicar dichas diferencias en términos de exploración radical, relaciones hídricas, asimilación de carbono, eficiencia en el uso del agua y partición de asimilados se realizó un ensa-yo a campo de cv. Malbec sobre seis portainjertos (3309 C, 1103 P, 140 Ru, SO4, Harmony y Cereza) y a pie franco. Los portainjertos 140 Ru, 1103 P y SO4 tuvieron una mayor tendencia a la producción de uva (mayor Índice de Ravaz), y Franco, Cereza y 3309 C a vegetar, mostrando Harmony una situación intermedia. Las ba-yas sobre el pie Cereza tuvieron un mayor peso (1,96 g) que sobre Harmony (1,75 g). No se encontraron diferencias en los polifenoles de las bayas entre portainjertos. La fotosíntesis de la planta entera (Amax) de Franco, 1103 P y SO4 fue mayor que la de Harmony. La conductancia hidráulica foliar específica (kL) de Harmony fue me-nor que la de Cereza, y su conductancia hidráulica (kH) fue menor que la de Franco, Cereza y SO4. El número de raíces totales de 140 Ru fue mayor que el de 1103 P, SO4 y Harmony. El portainjerto 140 Ru se destacó por privilegiar el desarrollo radi-cal y reproductivo sobre el vegetativo, y por su mayor eficiencia en el uso del agua (EUA). Las diferencias entre portainjertos pueden ser explicadas en parte por dife-rencias en la kL que a su vez incide en el estado hídrico de las plantas (ΨL). De ma-nera que cuando la kL es más baja, el ΨL es menor (i.e., Harmony), y cuando la kL es más alta, el ΨL es mayor (i.e., Franco y Cereza). Mayores ΨL se asocian con mayores superficies foliares.

Uso de agua en industrias de elaboración de conservas de tomate y de durazno de Mendoza, Argentina

El objetivo de este trabajo es conocer, a nivel de cuenca, el volumen de agua utilizado por las industrias de elaboración de conservas de tomate y de durazno de Mendoza. Para ello se estima la materia prima utilizada en la elaboración de estas conservas a partir de datos de superficie cultivada para tal destino y de rendimientos por superficie obtenidos en el Registro Permanente de Uso de la Tierra de Mendoza y el Instituto Nacional de Tecnología Agropecuaria. Se emplearon coeficientes de volumen de agua utilizada por unidad de materia prima procesada, que varían entre 5 y 25 L kg-1 de producto procesado, sin incluir el uso de agua para riego en fincas. Los resultados se analizaron para diferentes valores de coeficientes asociados a la eficiencia del uso del agua, en escenarios optimista y pesimista. Se concluye que las industrias elaboradoras de conservas de tomate y de durazno de Mendoza utilizan entre 0,66 y 6,15 hm3/año. El mayor consumo de agua de las conserveras de tomate ocurre en la cuenca Norte, alcanzando el 64,9% del total demandado por tales industrias. Para las conserveras de durazno, el mayor consumo se produce en la cuenca Sur con un 46% de total demandado.