Cellular Compartmentation of Zinc in Leaves of the Hyperaccumulator Thlaspi caerulescens1

Cellular compartmentation of Zn in the leaves of the hyperaccumulator Thlaspi caerulescens was investigated using energy-dispersive x-ray microanalysis and single-cell sap extraction. Energy-dispersive x-ray microanalysis of frozen, hydrated leaf tissues showed greatly enhanced Zn accumulation in the epidermis compared with the mesophyll cells. The relative Zn concentration in the epidermal cells correlated linearly with cell length in both young and mature leaves, suggesting that vacuolation of epidermal cells may promote the preferential Zn accumulation. The results from single-cell sap sampling showed that the Zn concentrations in the epidermal vacuolar sap were 5 to 6.5 times higher than those in the mesophyll sap and reached an average of 385 mm in plants with 20,000 μg Zn g−1 dry weight of shoots. Even when the growth medium contained no elevated Zn, preferential Zn accumulation in the epidermal vacuoles was still evident. The concentrations of K, Cl, P, and Ca in the epidermal sap generally decreased with increasing Zn. There was no evidence of association of Zn with either P or S. The present study demonstrates that Zn is sequestered in a soluble form predominantly in the epidermal vacuoles in T. caerulescens leaves and that mesophyll cells are able to tolerate up to at least 60 mm Zn in their sap.

pH-Regulated Leaf Cell Expansion in Droughted Plants Is Abscisic Acid Dependent1

Elongation rates of barley (Hordeum vulgare L. cv Hanna) leaves decreased with decreasing soil water content, whereas the pH of xylem sap increased from 5.9 to 6.9 over 6 d as the soil dried. The reduction in leaf-elongation rate (LER) was correlated with the increase in sap pH. Artificial sap buffered to different pH values was fed via the subcrown internode to derooted seedlings. Although leaves elongated at in planta rates when fed artificial sap at a well-watered pH of 6.0, LER declined with increasing sap pH. This effect persisted in the light and in the dark. pH had no effect on the relative water content or the bulk abscisic acid (ABA) concentration of the growing zone of these leaves. LERs of the ABA-deficient mutant Az34 were uniformly high over the pH range tested, whereas those of its isogenic wild-type cultivar Steptoe were reduced as the artificial sap pH was increased from 6.0 to 7.0. However, supplying a well-watered concentration of ABA (3 × 10−8 m) in the artificial xylem sap restored the pH response of the Az34 mutant. The results suggest that increased xylem sap pH acts as a drought signal to reduce LER via an ABA-dependent mechanism.

Altered Zn Compartmentation in the Root Symplasm and Stimulated Zn Absorption into the Leaf as Mechanisms Involved in Zn Hyperaccumulation in Thlaspi caerulescens

We investigated Zn compartmentation in the root, Zn transport into the xylem, and Zn absorption into leaf cells in Thlaspi caerulescens, a Zn-hyperaccumulator species, and compared them with those of a related nonaccumulator species, Thlaspi arvense. 65Zn-compartmental analysis conducted with roots of the two species indicated that a significant fraction of symplasmic Zn was stored in the root vacuole of T. arvense, and presumably became unavailable for loading into the xylem and subsequent translocation to the shoot. In T. caerulescens, however, a smaller fraction of the absorbed Zn was stored in the root vacuole and was readily transported back into the cytoplasm. We conclude that in T. caerulescens, Zn absorbed by roots is readily available for loading into the xylem. This is supported by analysis of xylem exudate collected from detopped Thlaspi species seedlings. When seedlings of the two species were grown on either low (1 μm) or high (50 μm) Zn, xylem sap of T. caerulescens contained approximately 5-fold more Zn than that of T. arvense. This increase was not correlated with a stimulated production of any particular organic or amino acid. The capacity of Thlaspi species cells to absorb 65Zn was studied in leaf sections and leaf protoplasts. At low external Zn levels (10 and 100 μm), there was no difference in leaf Zn uptake between the two Thlaspi species. However, at 1 mm Zn2+, 2.2-fold more Zn accumulated in leaf sections of T. caerulescens. These findings indicate that altered tonoplast Zn transport in root cells and stimulated Zn uptake in leaf cells play a role in the dramatic Zn hyperaccumulation expressed in T. caerulescens.

The Role of Cytosolic Potassium and pH in the Growth of Barley Roots1

In an earlier paper we showed that in fully developed barley (Hordeum vulgare L.) root epidermal cells a decrease in cytosolic K+ was associated with an acidification of the cytosol (D.J. Walker, R.A. Leigh, A.J. Miller [1996] Proc Natl Acad Sci USA 93: 10510–10514). To show that these changes in cytosolic ion concentrations contributed to the decreased growth of K+-starved roots, we first measured whether similar changes occurred in cells of the growing zone. Triple-barreled ion-selective microelectrodes were used to measure cytosolic K+ activity and pH in cells 0.5 to 1.0 mm from the root tip. In plants growing from 7 to 21 d after germination under K+-replete conditions, the mean values did not change significantly, with values ranging from 80 to 84 mm for K+ and 7.3 to 7.4 for pH. However, in K+-starved plants (external [K+], 2 μm), the mean cytosolic K+ activity and pH had declined to 44 mm and 7.0, respectively, after 14 d. For whole roots, sap osmolality was always lower in K+-starved than in K+-replete plants, whereas elongation rate and dry matter accumulation were significantly decreased after 14 and 16 d of K+ starvation. The rate of protein synthesis in root tips did not change for K+-replete plants but declined significantly with age in K+-starved plants. Butyrate treatment decreased cytosolic pH and diminished the rate of protein synthesis in K+-replete roots. Procaine treatment of K+-starved roots gave an alkalinization of the cytosol and increased protein synthesis rate. These results show that changes in both cytosolic pH and K+ can be significant factors in inhibiting protein synthesis and root growth during K+ deficiency.

High Aluminum Resistance in Buckwheat1 : II. Oxalic Acid Detoxifies Aluminum Internally

Buckwheat (Fagopyrum esculentum Moench. cv Jianxi), which shows high Al resistance, accumulates Al in the leaves. The internal detoxification mechanism was studied by purifying and identifying Al complexes in the leaves and roots. About 90% of Al accumulated in the leaves was found in the cell sap, in which the dominant organic acid was oxalic acid. Purification of the Al complex in the cell sap of leaves by molecular-sieve chromatography resulted in a complex with a ratio of Al to oxalic acid of 1:3. A 13C-nuclear magnetic resonance study of the purified cell sap revealed only one signal at a chemical shift 164.4 ppm, which was assigned to the Al-chelated carboxylic group of oxalic acid. A 27Al-nuclear magnetic resonance analysis revealed one major signal at the chemical shift of 16.0 to 17.0 ppm, with a minor signal at the chemical shift of 11.0 to 12 ppm in both the intact roots and their cell sap, which is consistent with the Al-oxalate complexes at 1:3 and 1:2 ratios, respectively. The purified cell sap was not phytotoxic to root elongation in corn (Zea mays). All of these results indicate that Al tolerance in the roots and leaves of buckwheat is achieved by the formation of a nonphytotoxic Al-oxalate (1:3) complex.

Effects of Xylem pH on Transpiration from Wild-Type and flacca Tomato Leaves1 : A Vital Role for Abscisic Acid in Preventing Excessive Water Loss Even from Well-Watered Plants

The pH of xylem sap from tomato (Lycopersicon esculentum) plants increased from pH 5.0 to 8.0 as the soil dried. Detached wild-type but not flacca leaves exhibited reduced transpiration rates when the artificial xylem sap (AS) pH was increased. When a well-watered concentration of abscisic acid (0.03 μm) was provided in the AS, the wild-type transpirational response to pH was restored to flacca leaves. Transpiration from flacca but not from wild-type leaves actually increased in some cases when the pH of the AS was increased from 6.75 to 7.75, demonstrating an absolute requirement for abscisic acid in preventing stomatal opening and excessive water loss from plants growing in many different environments.

Phloem Transport of Fructans in the Crassulacean Acid Metabolism Species Agave deserti1

Four oligofructans (neokestose, 1-kestose, nystose, and an un-identified pentofructan) occurred in the vascular tissues and phloem sap of mature leaves of Agave deserti. Fructosyltransferases (responsible for fructan biosynthesis) also occurred in the vascular tissues. In contrast, oligofructans and fructosyltransferases were virtually absent from the chlorenchyma, suggesting that fructan biosynthesis was restricted to the vascular tissues. On a molar basis, these oligofructans accounted for 46% of the total soluble sugars in the vascular tissues (sucrose [Suc] for 26%) and for 19% in the phloem sap (fructose for 24% and Suc for 53%). The Suc concentration was 1.8 times higher in the cytosol of the chlorenchyma cells than in the phloem sap; the nystose concentration was 4.9 times higher and that of pentofructan was 3.2 times higher in the vascular tissues than in the phloem sap. To our knowledge, these results provide the first evidence that oligofructans are synthesized and transported in the phloem of higher plants. The polymer-trapping mechanism proposed for dicotyledonous C3 species may also be valid for oligofructan transport in monocotyledonous species, such as A. deserti, which may use a symplastic pathway for phloem loading of photosynthates in its mature leaves.

Serum amyloid P component prevents proteolysis of the amyloid fibrils of Alzheimer disease and systemic amyloidosis.

Extracellular deposition of amyloid fibrils is responsible for the pathology in the systemic amyloidoses and probably also in Alzheimer disease [Haass, C. & Selkoe, D. J. (1993) Cell 75, 1039-1042] and type II diabetes mellitus [Lorenzo, A., Razzaboni, B., Weir, G. C. & Yankner, B. A. (1994) Nature (London) 368, 756-760]. The fibrils themselves are relatively resistant to proteolysis in vitro but amyloid deposits do regress in vivo, usually with clinical benefit, if new amyloid fibril formation can be halted. Serum amyloid P component (SAP) binds to all types of amyloid fibrils and is a universal constituent of amyloid deposits, including the plaques, amorphous amyloid beta protein deposits and neurofibrillary tangles of Alzheimer disease [Coria, F., Castano, E., Prelli, F., Larrondo-Lillo, M., van Duinen, S., Shelanski, M. L. & Frangione, B. (1988) Lab. Invest. 58, 454-458; Duong, T., Pommier, E. C. & Scheibel, A. B. (1989) Acta Neuropathol. 78, 429-437]. Here we show that SAP prevents proteolysis of the amyloid fibrils of Alzheimer disease, of systemic amyloid A amyloidosis and of systemic monoclonal light chain amyloidosis and may thereby contribute to their persistence in vivo. SAP is not an enzyme inhibitor and is protective only when bound to the fibrils. Interference with binding of SAP to amyloid fibrils in vivo is thus an attractive therapeutic objective, achievement of which should promote regression of the deposits.

Interazioni piante - insetti: ruolo delle formiche in un sistema multitrofico. Aspetti ecoetologici ed applicativi

Le formiche svolgono un importante ruolo all’interno degli ecosistemi ed alcune specie sono considerate keystone in quanto in grado di modificare la componente biotica e/o abiotica dell’ecosistema stesso. Sono animali ubiquitari che hanno colonizzato molteplici ambienti, compresi gli agroecosistemi. Negli agroecosistemi spesso svolgono un ruolo impattante determinando la diffusione o il regresso di specie di artropodi, alcune delle quali dannose alle colture. La presente ricerca tiene conto di un’ampia visione dei rapporti ecoetologici intercorrenti tra le formiche e la componente biotica di un ecosistema, utilizzando il concetto di rete multitrofica. In quest’ottica, si è pensato di costruire un sistema multitrofico costituito da una specie vegetale di interesse agrario (Cucumis sativus), dai suoi fitofagi naturali, divisi in fitomizi (afidi) (Aphis gossypii e Myzus persicae) e fitofagi masticatori (bruchi del lepidottero Mamestra brassicae), formiche (Formica pratensis) e predatori afidofagi (Aphidolets aphidimyza). Il sistema multitrofico è stato utilizzato sia per studiare l’aggressività delle formiche, sia per verificare l’esistenza di una comunicazione interspecifica tra le formiche e le piante (allelochimici). Gli studi sull’aggressività sono consistiti nel: • Verificare il livello di aggressività delle formiche nei confronti di un fitofago masticatore, competitore degli afidi nello sfruttare la pianta ospite. • Verificare se la presenza di afidi mutualisti fa variare il livello di aggressività delle formiche verso il competitore. • Verificare se esiste aggressività verso un predatore di afidi, i quali, secondo il paradigma della trofobiosi, dovrebbero essere difesi dalle formiche in cambio della melata. • Verificare se il predatore ha evoluto strategie volte ad eludere il controllo delle formiche sugli insetti che si approcciano alla colonia di afidi. Gli studi sui rapporti piante-formiche sono stati effettuati mediante olfattometro, osservando la risposta delle formiche alle sostanze volatili provenienti da piante infestate in modo differente con i fitofagi del sistema. Attraverso il trappolaggio e l’analisi gas-cromatografica delle sostanze prodotte dalle piante oggetto di studio abbiamo quindi individuato tipo e quantità di ogni composto volatile. Oltre alle piante di cetriolo, per questi esperimenti sono state utilizzate anche piante di patata (Solanum tuberosum). Dagli esperimenti sull’aggressività è risultato che le formiche manifestano un elevato potenziale predatorio, eradicando completamente la presenza dei bruchi sulle piante. Questo livello di aggressività tuttavia non cresce con la presenza degli afidi mutualisti che dovrebbero essere difesi dai competitori. Le formiche inoltre non sono in grado di sopprimere i predatori afidofagi che ipotizziamo riescano ad effettuare un camuffamento chimico, assumendo gli odori degli afidi dei quali si nutrono. I risultati degli esperimenti in olfattometro mostrano una chiara risposta positiva delle formiche verso gli odori di alcune delle piante infestate. Vi sono delle differenze nella risposta in funzione della specie di fitofago presente e della specie di pianta utilizzata. Nei trattamenti in cui erano presenti le piante di C. sativus, gli esperimenti in olfattometro hanno mostrato che le formiche rispondono in modo significativo agli odori emessi dalle piante in cui vi era la presenza del fitofago masticatore M. brassicae, solo o in associazione con A. gossypii. La presenza dei soli afidi, sia mutualisti (A. gossypii) sia non mutualisti (M. persicae), non ha invece indotto una risposta significativa nelle formiche rispetto agli odori delle piante non infestate. Nei trattamenti in cui erano presenti le piante di S. tuberosum la scelta delle formiche è stata significativa verso gli odori emessi dalle piante infestate con ciascuna delle singole specie di erbivori rispetto alle piante non infestate. Gli esperimenti sull’analisi delle sostanze volatili emesse dalle piante hanno confermato che gli organismi vegetali sono una vera centrale di produzione biochimica, infatti ben 91 composti volatili diversi sono stati individuati dall’analisi gas-cromatografica delle piante di cetriolo e 85 in quelle di patata. Dalle elaborazioni effettuate, rispettivamente 27 e 4 di essi sono prodotti esclusivamente dalle piante attaccate dai fitofagi. In generale, il cambiamento più consistente è dato dalla quantità di alcune sostanze volatili emesse dalle piante infestate rispetto a quelle integre che determina un cambiamento nei rapporti tra le sostanze che compongono i volatiles. E’ probabile che l’effetto attrattivo esercitato sulle formiche sia dato da un Blend di sostanze più che dai singoli composti presenti

Personas mayores en situación de aislamiento social: diseño y efectividad de un servicio de apoyo psicológico

La exclusión y el aislamiento social son fenómenos complejos y multidimensionales que afectan a la vida de las personas, excluyéndolas de la sociedad en la que viven, privándoles de sus derechos sociales, fomentando la desigualdad y, finalmente, afectando a su dignidad e identidad personal y social. La población mayor de 65 años es un grupo especialmente vulnerable puesto que se añaden factores de fragilidad y dependencia funcional. El aislamiento social en las personas mayores es un problema de salud pública que va en aumento, debido, por un lado, a la cada vez mayor proporción de personas mayores en nuestra sociedad y, por otro lado, los efectos negativos que el aislamiento social tiene sobre su salud, física y mental, y su bienestar. Sin embargo, la investigación acerca de las intervenciones llevadas a cabo hasta el momento no arroja unos resultados concluyentes acerca de su efectividad, ni de las características que deberían tener para resultar rentables y conseguir los objetivos terapéuticos propuestos. Dada esta situación, la presente tesis propone una intervención basada en las estrategias de búsqueda activa, seguimiento del caso y continuidad, presentando el Servicio de Apoyo Psicológico al Mayor en Aislamiento Social (SAP) en la ciudad de Madrid y sus tres protocolos de actuación: Contacto y enganche, Evaluación e Intervención. Los objetivos que se plantean son: 1) describir el proceso de implantación del SAP; 2) avanzar en la descripción de la población mayor de 65 años en aislamiento social en la ciudad de Madrid respecto a variables sociodemográficas, de salud y funcionamiento psicosocial, necesidades sociosanitarias, funcionamiento global, discapacidad, deterioro cognitivo y sintomatología psicopatológica; y 3) evaluar la efectividad de la intervención llevada a cabo por el SAP mediante un análisis de las medidas de salud y funcionamiento psicosocial, necesidades sociosanitarias, funcionamiento global y discapacidad previas y posteriores a la intervención...

Corn Liberalization in Mexico: The Effects of Neoliberal Policies on Campesino Food Security

Mexico has a long history of structuralized violence against its most vulnerable socioeconomic strata, the peasantry, also referred to as Campesinos. From the Spanish invasion, to the contemporary neoliberal development project, corn production has been intimately associated with disparate power relations both within Mexican society, and without, particularly in relations with the United States. This study sheds light on the incongruities of modernism implicit within neoliberal policy instruments such as Structural Adjustment Programs (SAP) and free trade agreements. It will demonstrate that while such policies benefit some, they principally exacerbate existing power disparities via disarticulated trade economics, subordinating rather than liberating Mexico's most vulnerable citizenry.

La palmera datilera y la palmera canaria en la medicina tradicional de España

En la actualidad son muy pocos los usos vigentes. Aunque los dátiles son la materia utilizada con mayor frecuencia, también se han empleado la savia, el polen y el cogollo tierno o palmito. Los dátiles de Phoenix dactylifera se utilizaron como analgésico y para tratar la anemia y trastornos digestivos, o para fortalecer las encías, en el tratamiento de la disfunción eréctil y como afrodisiacos, para facilitar el parto y calmar los dolores postparto, y tratar el prolapso de la matriz o para el exceso de flujo menstrual. También se utilizaron como diuréticos, para la disuria y en trastornos de la vejiga. El uso que más claramente ha persistido es el tratamiento de diversos problemas respiratorios. En uso externo se utilizaron para tratar problemas de la piel, heridas, hemorragias y hemorroides. De la palmera de Canarias (Phoenix canariensis), especialmente en la isla de la Gomera, la savia cruda o guarapo, su concentrado o miel de palma y los resultantes de su fermentación (vino de palma) se consumen como alimento y también se utilizan como diurético, remedio de trastornos génitourinarios, digestivo, para infecciones de la cavidad bucal, expectorante, antitusígeno y para las irritaciones de garganta. En el Toledo de Al-Andalus las espatas de P. dactylifera se utilizaron, hace casi mil años, en el tratamiento de la debilidad, los dolores, nefritis, las enfermedades de la vejiga, trastornos hepáticos (también como preventivo), diarrea, trastornos digestivos, dolores en el abdomen y en el estómago, excesivo sangrado menstrual, úlceras en la piel y sarna, dolores articulares y trastornos cardiacos. La fitoterapia racional debería prestar atención a este recurso, considerar la evidencia científica disponible (farmacológica e incluso clínica) e incorporarlo a nuestro repertorio terapéutico.

The effect of extreme cold temperatures on the risk of death in the two major Portuguese cities

It is well known that meteorological conditions influence the comfort and human health. Southern European countries, including Portugal, show the highest mortality rates during winter, but the effects of extreme cold temperatures in Portugal have never been estimated. The objective of this study was the estimation of the effect of extreme cold temperatures on the risk of death in Lisbon and Oporto, aiming the production of scientific evidence for the development of a real-time health warning system. Poisson regression models combined with distributed lag non-linear models were applied to assess the exposure-response relation and lag patterns of the association between minimum temperature and all-causes mortality and between minimum temperature and circulatory and respiratory system diseases mortality from 1992 to 2012, stratified by age, for the period from November to March. The analysis was adjusted for over dispersion and population size, for the confounding effect of influenza epidemics and controlled for long-term trend, seasonality and day of the week. Results showed that the effect of cold temperatures in mortality was not immediate, presenting a 1–2-day delay, reaching maximumincreased risk of death after 6–7 days and lasting up to 20–28 days. The overall effect was generally higher and more persistent in Lisbon than in Oporto, particularly for circulatory and respiratory mortality and for the elderly. Exposure to cold temperatures is an important public health problem for a relevant part of the Portuguese population, in particular in Lisbon.

Data capturing: studio di fattibilità per l’acquisizione automatizzata delle informazioni lungo la catena produttiva

Il processo di Data Entry manuale non solo è oneroso dal punto di vista temporale ed economico, lo è ancor di più poiché rappresenta una fonte di errore: per questi motivi, l’acquisizione automatizzata delle informazioni lungo la catena produttiva è un obiettivo fortemente desiderato dal Gruppo per migliorare i propri business. Le tecnologie analizzate, ormai diffuse e standardizzate in ampia scala come barcode, etichette logistiche, terminali in radiofrequenza, possono apportare grandi benefici ai processi aziendali, ancor più integrandole su misura agli ERP aziendali, permettendo una registrazione rapida e corretta delle informazioni e la diffusione immediata delle stesse all’intera organizzazione. L’analisi dei processi e dei flussi hanno evidenziato le criticità e permesso di capire dove e quando intervenire con una progettazione che risultasse quanto più la best suite possibile. Il lancio dei fabbisogni, l’entrata, la mappatura e la movimentazione merci in Magazzino, lo stato di produzione, lo scarico componenti ed il carico di produzione in Confezionamento e Semilavorazione, l’istituzione di un magazzino di interscambio Dogana, un flusso di tracciabilità preciso e rapido, sono tutti eventi che modificheranno i processi aziendali, snellendoli e svincolando risorse che potranno essere reinvestite in operatività a valore aggiunto superiore. I risultati potenzialmente ottenibili, comprovati anche dalle esperienze esterne di fornitori e consulenza, hanno generato le condizioni necessarie ad un rapido studio e start dei lavori: il Gruppo è entusiasta ed impaziente di portare a termine quanto prima il progetto e di andare a regime con la nuova modalità operativa, snellita ed ottimizzata.