The activation of iron deficiency responses of grapevine rootstocks is dependent to the availability of the nitrogen forms.

BACKGROUND: In viticulture, iron (Fe) chlorosis is a common abiotic stress that impairs plant development and leads to yield and quality losses. Under low availability of the metal, the applied N form (nitrate and ammonium) can play a role in promoting or mitigating Fe deficiency stresses. However, the processes involved are not clear in grapevine. Therefore, the aim of this study was to investigate the response of two grapevine rootstocks to the interaction between N forms and Fe uptake. This process was evaluated in a hydroponic experiment using two ungrafted grapevine rootstocks Fercal (Vitis berlandieri x V. vinifera) tolerant to deficiency induced Fe chlorosis and Couderc 3309 (V. riparia x V. rupestris) susceptible to deficiency induced Fe chlorosis. RESULTS: The results could differentiate Fe deficiency effects, N-forms effects, and rootstock effects. Interveinal chlorosis of young leaves appeared earlier on 3309 C from the second week of treatment with NO3-/NH4+ (1:0)/-Fe, while Fercal leaves showed less severe symptoms after four weeks of treatment, corresponding to decreased chlorophyll concentrations lowered by 75% in 3309 C and 57% in Fercal. Ferric chelate reductase (FCR) activity was by trend enhanced under Fe deficiency in Fercal with both N combinations, whereas 3309 C showed an increase in FCR activity under Fe deficiency only with NO3-/NH4+ (1:1) treatment. With the transcriptome analysis, Gene Ontology (GO) revealed multiple biological processes and molecular functions that were significantly regulated in grapevine rootstocks under Fe-deficient conditions, with more genes regulated in Fercal responses, especially when both forms of N were supplied. Furthermore, the expression of genes involved in the auxin and abscisic acid metabolic pathways was markedly increased by the equal supply of both forms of N under Fe deficiency conditions. In addition, changes in the expression of genes related to Fe uptake, regulation, and transport reflected the different responses of the two grapevine rootstocks to different N forms. CONCLUSIONS: Results show a clear contribution of N forms to the response of the two grapevine rootstocks under Fe deficiency, highlighting the importance of providing both N forms (nitrate and ammonium) in an appropriate ratio in order to ease the rootstock responses to Fe deficiency.

Algunas consideraciones en relación con la administración de hierro / Topics abourt iron administration

La deficiencia de hierro es la causa productora de anemia más frecuente de todas las conocidas. En muchos países se ha considerado como un grave problema de salud pública. En cuanto al tratamiento específico han surgido controversias importantes en los últimos 15 años. En relación a mecanismos de inmunidad, algunaos autores han informado susceptibilidad , aumentada a las infecciones, otros en cambio han encontrado una incidencia menor e incluso varios investigadores han demostrado infecciones frecuentes en pacientes con sobrecarga de hierro. Se discuten los cambios anatómicos y funcionales que se producen por el balance negativo de hierro en las células linfoides y en los fagocitos. Se comentan las controversias sobre ventajas y efectos indeseables de las diferentes vías de administración

Diferenciaçäo entre talassemia beta-heterozigótica e anemia ferropriva / Differentiation between heterozygotic beta-thalassemia and iron deficiency anemia

Várias funcöes discriminantes baseadas nos parâmetros hematimétricos fornecidos pelos contadores eletrônicos de células têm sido desenvolvidas e utilizadas nas diferenciaçäo de várias formas de anemia. A eficiência de alguns desses critérios comumente empregados na distinçäo entre a talassemia beta-heterozigótica e a anemia ferropriva foi testada em 192 indivíduos talassêmicos e em 72 adultos com anemia ferropriva. Foram avaliados: 1) funçäo discriminante de England e Fraser: VCM - (5xHb) - H - 8,4;2) HCM/H; 3) relaçäo de Mentzer: VCM/H; 4) (VCM)² x HCM; e 5) número de hemácias. Os resultados obtidos demonstraram falha na distinçäo entre estas duas entidades, em percentagens variáveis de 9 a 90//, sendo que a equaçäo de England e Fraser demonstrou os resultados mais satisfatórios, enquanto a relaçäo de Mentzer apresentou maiores índices de erro no diagnóstico da anemia ferropriva. Assim, embora algumas dessas fármulas possam ser utilizadas em programa de triagem, em casos individuais a diferenciaçäo entre talassemia beta-heterozigótica e anemia ferropriva deve ser sempre realizada com dosagens de HbA2, ferro sérico, capacidade máxima de transporte de ferro e ferritina

Frecuencia de las alteraciones del metabolismo del hierro / Frequency of the iron metabolism disorders

MARCO TEORICO: Los desórdenes del metabolismo del hierro constituyen el problema nutricional de mayor prevalencia en el mundo, sobre todo en países en desarrollo como el nuestro. OBJETIVO: Conocer la frecuencia de las alteraciones del metabolismo del hierro de la población que acude al Laboratorio del Hospital A.B.C. a través de la determinación de Hb en g/dL y el porcentaje de Saturación de transferrina TIPO DE ESTUDIO: Retrospectivo RESULTADOS: Existe deficienia de hierro en promedio en 1 de cada 4 individuos estudiados (p<0.05). CONCLUSION: Es necesario establecer un sistema de detección para el tratamiento específico y oportuno de este problema.