Search

Mastic trees (Pistacia lentiscus L.) are dioecious perennial plants that are highly adapted to Mediterranean climates but display a high sensitivity to winter periods. In order to understand how sex, leaf phenology and ecological context could condition sensitivity to winter and associated mechanisms to acclimate to these conditions, photoinhibition and photo-oxidative stress markers were examined in mastic trees (P. lentiscus) from a natural population growing in the Garraf Natural Park for a consecutive 12-month period (seasonal study), as well as in three populations naturally growing in the Montseny Natural Park, including the highest altitudes described for this species, during winter (altitudinal study). Results from these studies indicate that both the winter period and higher elevation influenced the degree of photoinhibition, but this was not conditioned by sex. In fact, winter photoinhibition occurred transiently even though it was accompanied by chlorophyll loss and malondialdehyde contents. Stress acclimation was achieved through biochemical adjustments in chloroplasts, characterized by anthocyanin shielding, increased de-epoxidation state of the xanthophyll cycle as well as tocopherol accumulation, and phenological adaptations, the latter allowing a complete resetting of the physiological performance of leaves. Moreover, although females showed higher lipid peroxidation than males during the coldest winter months, at the highest elevation and during flowering in spring, this oxidative stress was mild and transient with no negative consequences for the physiology of plants. It is concluded that evergreen mastic trees acclimate to winter conditions and higher elevations by activation of antioxidant defenses together with phenological adjustments, altogether playing a crucial role in plant survival. Sexual dimorphism in mastic trees appears as a relevant factor when considering sensitivity to photo-oxidative stress in winter and altitudinal conditions. [ABSTRACT FROM AUTHOR]

In the context of future climate change new habitats will be threatened and unique species will be forced to develop different strategies to survive. Saxifraga longifolia Lapeyr. is an endemic species from the Pyrenees with a very particular habitat. We explored the capacity and strategies of S. longifolia plants to face different severities of drought stress under both natural conditions and controlled water stress followed by a re‐watering period of 20 days. Our results showed a role for abscisic acid (ABA), salicylic acid (SA) and cytokinins (CKs) in plant survival from drought stress, and as the stress increased, ABA lost significance and SA appeared to be more associated with the response mechanisms. Moreover, photo‐oxidative stress markers revealed that both xanthophyll cycles played a photoprotection role with a stronger participation of the lutein epoxide cycle as the stress was more intense. Severe drought decreased the maximum efficiency of photosystem II (Fv/Fm) below 0.45, being this the limit to survive upon rewatering. Overall, our results proved different strategies of S. longifolia plants to cope with drought stress and suggested a Fv/Fm threshold to predict plant survival in high‐mountain environments. [ABSTRACT FROM AUTHOR]

Background and Aims Monocarpic plants are those that flower, produce seeds and then die. Although most monocarpic plants are annual or biennial, some of them are perennial. However, relatively little is known regarding the biology of monocarpic perennials. Pyrenean saxifrage (Saxifraga longifolia) is a monocarpic perennial that is well adapted to high-mountain ecosystems. Here, we evaluated altitudinal changes in clonality in various populations growing in their natural habitat with particular emphasis on the physiological costs of clonal growth. Methods We assessed the percentage of clonal plants in nine populations growing in their natural habitat, as well as the plant stress response of clonal and non-clonal plants, in terms of photoprotection and accumulation of stress-related phytohormones, in a 3-year study at Las Blancas (2100 m a.s.l.). We also evaluated the influence of plant size on the activation of defensive responses to biotic and abiotic stresses. Key Results We found that 12 % of Pyrenean saxifrage plants growing at the highest altitudes (2100 m a.s.l.) produced lateral rosettes which survived the flowering of the main rosette and shared the same axonomorphic root, thus escaping monocarpic senescence. This clonal growth did not worsen the physiological performance of plants growing at this altitude. Furthermore, increased plant size did not negatively affect the physiology of plants, despite adjustments in endogenous stress-related phytohormones. In contrast, maturity led to rapid physiological deterioration of the rosette, which was associated with monocarpic senescence. Conclusions This study shows that the evolution of clonality has allowed Pyrenean saxifrage to survive harsh environmental conditions and it provides evidence that harsh environments push plant species to their limits in terms of life form and longevity. [ABSTRACT FROM AUTHOR]

Jasmonates are widely found in the plant kingdom and play a key role in both plant biotic and abiotic defense and plant development. Jasmonates activity under abiotic stress conditions have been extensively investigated in model plants, but little is known about the bioactive forms and their functions in non-model species, particularly in plants growing in their natural environment. Here, we performed a jasmonate profiling approach to unravel changes in the specific jasmonate signature of leaves as a function of environmental conditions, including the measurement of both free and conjugated forms of jasmonates by UHPLC–MS/MS, during the summer and autumn in Saxifraga longifolia plants growing in their natural habitat in the Pyrenees. We evaluated the climatological factors governing specific jasmonate signatures and the correlation between jasmonate accumulation and leaf morphology, PSII efficiency and pigment accumulation, including anthocyanins, chlorophylls and carotenoids. The results showed a jasmonate profiling characterized by an accumulation of free jasmonic acid and its precursor, 12- oxo -phytodienoic acid, with the amino acid conjugated forms being much less abundant. Among amino acid conjugates, jasmonoyl-isoleucine, jasmonoyl-valine and jasmonoyl-phenylalanine were the most abundant forms. Contents of 12- oxo -phytodienoic acid decreased, while those of free jasmonic acid increased during summer drought stress events. The five amino acid conjugated forms did respond similarly to environmental changes with progressive decreases from summer to autumn, but irrespective of drought events. Endogenous contents of free jasmonic acid correlated positively with those of anthocyanins. Furthermore, exogenous jasmonate applications on leaves increased anthocyanin contents, thus confirming a link between jasmonates and anthocyanin accumulation in S. longifolia plants. [ABSTRACT FROM AUTHOR]

The transition phase in plants, which is marked by the onset of flowering and seed production, is very sensitive to the physical environment. Moreover, dimorphic plant species can show important sex-related differences in the response to nutrient availability. How availability of inorganic phosphate (Pi) during the transition phase influences sex ratios and whether or not male and female plants respond differently to nutrient stress is still however very poorly understood. Here, we examined whether contrasting Pi availability during the transition phase may influence sexual differentiation in stinging nettle ( U. dioica L.) plants. We also evaluated to what extent males and females respond differently to varying Pi concentrations in terms of nutrient accumulation, C and N isotopic composition, photo-oxidative stress and hormone profiling. Results showed that reduced Pi availability delays plant maturation in males, causing as well an increase in the sex ratio towards females. Females showed enhanced lipid peroxidation (as indicated by higher lipid hydroperoxide contents) compared to males under Pi starvation, but sexes did not differ in photosystem II efficiency. Furthermore, reduced Pi availability led to enhanced 12- oxo -phytodienoic acid contents, the immediate precursor of jasmonic acid, particularly in females. This increase was, however, not accompanied by increases in other jasmonates, neither free nor conjugated jasmonic acid, thus suggesting a specific role for 12- oxo -phytodienoic acid in chemical defense in females under Pi starvation. Sex biased ratios in favour of females over males and enhanced 12- oxo -phytodienoic acid contents in the former under Pi starvation illustrate the great adaptive capacity of dimorphic species to reduced nutrient availability. [ABSTRACT FROM AUTHOR]

The transition phase in plants, which is marked by the onset of flowering and seed production, is very sensitive to the physical environment. Moreover, dimorphic plant species can show important sex-related differences in the response to nutrient availability. How availability of inorganic phosphate (Pi) during the transition phase influences sex ratios and whether or not male and female plants respond differently to nutrient stress is still however very poorly understood. Here, we examined whether contrasting Pi availability during the transition phase may influence sexual differentiation in stinging nettle ( U. dioica L.) plants. We also evaluated to what extent males and females respond differently to varying Pi concentrations in terms of nutrient accumulation, C and N isotopic composition, photo-oxidative stress and hormone profiling. Results showed that reduced Pi availability delays plant maturation in males, causing as well an increase in the sex ratio towards females. Females showed enhanced lipid peroxidation (as indicated by higher lipid hydroperoxide contents) compared to males under Pi starvation, but sexes did not differ in photosystem II efficiency. Furthermore, reduced Pi availability led to enhanced 12- oxo -phytodienoic acid contents, the immediate precursor of jasmonic acid, particularly in females. This increase was, however, not accompanied by increases in other jasmonates, neither free nor conjugated jasmonic acid, thus suggesting a specific role for 12- oxo -phytodienoic acid in chemical defense in females under Pi starvation. Sex biased ratios in favour of females over males and enhanced 12- oxo -phytodienoic acid contents in the former under Pi starvation illustrate the great adaptive capacity of dimorphic species to reduced nutrient availability. [ABSTRACT FROM AUTHOR]

α-Actinin, an actin-binding protein of the spectrin superfamily, is present in most eukaryotes except plants. It is composed of three domains: N-terminal CH-domains, C-terminal calcium-binding domain (with EF-hand motifs), and a central rod domain. We have cloned and expressed Neurospora crassa α-actinin as GST and GFP fusion proteins for biochemical characterization and in vivo localization, respectively. The intracellular localization pattern of α-actinin suggests that this protein is intimately associated with actin filaments and plays an important role in the processes of germination, hyphal elongation, septum formation, and conidiation. These functions were confirmed by the experiments on the effect of α-actinin gene deletion in N. crassa. [ABSTRACT FROM AUTHOR]

Abstract: Spectrin was first described in erythrocytes where it forms a filamentous network in the cytoplasmic face of the plasma membrane and participates in the membrane’s structural integrity in addition to controlling the lateral mobility of integral membrane proteins. In fungi, spectrin-like proteins have been described in the plasma membrane, concentrated mainly in the region of maximum apical expansion. This localization led to the idea of a spectrin based membrane skeleton in fungi participating in mechanical integrity of the plasma membrane, generating and maintaining cell polarity. The occurrence of spectrin-like proteins in filamentous fungi, yeasts and Oomycetes, however, is questionable since the presence of such proteins has only been demonstrated with immunochemical methods using antibodies whose specificity is unclear. There is no evidence of a gene coding for the high molecular weight αβ-spectrin in the genome of these organisms. Mass spectrometric analysis of the anti αβ-spectrin immunoreacting peptides from Neurospora crassa and Phytophthora infestans identified them as elongation factor 2 (NCU07700.4) and Hsp70 (PITG_13237.1), respectively. An attempt was made to correlate the reactivity of anti-spectrin antibody to a common feature of these three proteins i.e., spectrin, elongation factor 2 and heat shock protein 70, in that they all have a hydrophobic region implicated in chaperon activity. [Copyright &y& Elsevier]

To investigate the functional significance of a cytoskeletal spectrin-like protein, we studied its localization pattern in Neurospora crassa and sought the answer to whether it is a substrate for another apically localized protein, the calcium-dependent protease (CDP II). Immunoblots of crude extracts from exponentially growing mycelia, separated by one- and two-dimensional sodium dodecyl sulfate–polyacrylamide gel electrophoresis using antichicken α/β-spectrin antibodies, revealed a single band of approximately relative mass (Mr) 100 kDa with an isoeletric point (pI) in the range of 6.5 to 7.0. Despite rigorous efforts, we could not confirm the presence of an Mr 240- to 220-kDa spectrin-like protein in N. crassa. The immunofluorescence- and immunogold-labeling Mr 100-kDa protein showed its predominance along the plasma membrane of the conidia during the swelling phase of germination. In contrast, in the germ tubes and the growing hyphae, the localization was polarized and concentrated mainly in the apical region. The in vitro proteolysis experiments showed that indeed this protein is a preferred substrate of CDP II which is, as mentioned previously, also localized in the apical regions of the hyphae. These results indicate a putative functional relationship between these two proteins (spectrin-like protein and CDP II) in the dynamics of tip growth. [ABSTRACT FROM AUTHOR]

• Physiological seed dormancy increases with elevation in Pyrenean saxifrage. • Abscisic acid modulates physiological dormancy in this high-mountain plant. • Enhanced xanthophyll contents may help to keep viability in dormant seeds. • Physiological seed dormancy may help to withstand stress at the highest altitudes. Seed dormancy determines population dynamics and it is an essential feature of the ecology of high-mountain plants. Although altitudinal changes in the ecological and physiological performance of Pyrenean saxifrage (Saxifraga longifolia Lapeyr.) has been investigated to some extent, nothing it still know about how seed dormancy is influenced by environmental conditions imposed by altitude in these plants. Here, we evaluated altitudinal changes in seed viability and germination, but also on the endogenous contents of phytohormones and antioxidants in Pyrenean saxifrage. We found that, despite seed germination decreased at the highest population (2100 m a.s.l.) relative to the other two populations (at 570 and 1100 m a.s.l.), the highest population showed the highest seed viability, thus indicating increased seed dormancy. Hormonal profiling of the seeds revealed that this dormancy was modulated physiologically, in particular by increased abscisic acid accumulation, while gibberellin contents kept constant, relative to the seeds of the other two populations. Furthermore, seed xanthophyll contents, in particular those of lutein, neoxanthin, violaxanthin and antheraxanthin increased with altitude, while those of α-tocopherol kept unaltered. We conclude that the lower temperature imposed by altitude strongly influences not only seed viability and germination, but also seed dormancy, and that changes associated to temperature differences among populations are modulated at the physiological level by increasing the accumulation of abscisic acid and xantophylls in mature seeds. Results strongly support the contention that physiological seed dormancy has evolved as a means to increase plant survival under harsh environmental conditions in Pyrenean saxifrage plants growing in their natural habitat. [ABSTRACT FROM AUTHOR]

Dimorphic plant species can show distinct nutrient needs due to sex-related differences in nutrient allocation to reproductive structures, which can potentially affect their sensitivity to photoinhibition and photo-oxidative stress. Here, we investigated sex-related differences in the extent of photo-oxidative stress in male and female individuals of U. dioica exposed to a combination of severe drought and nutrient starvation. Male and female individuals of U. dioica subject to severe drought stress were exposed to various levels of nutrient availability. First, a set of plants grown under field conditions and exposed to summer drought was used to test the effects of nutrient supply (given as NPK fertilizer). Secondly, the effects of various phosphate concentrations in the nutrient solution were tested in drought-stressed potted plants. The F v / F m ratio (maximum efficiency of PSII photochemistry), photoprotection capacity (levels of carotenoids, including the xanthophyll cycle, and vitamins C and E), and the extent of lipid peroxidation (hydroperoxide levels) were measured. Results showed that an application of the NPK fertilizer to the soil had a positive effect on drought-stressed plants, reducing the extent of lipid peroxidation in both males and females. P deficiency led to residual photoinhibition, as indicated by significant reductions in the F v / F m ratio, and enhanced lipid peroxidation in females, but not in males. We conclude that (i) increased nutrient availability in the soil can alleviate photo-oxidative stress in drought-stressed U. dioica plants, and (ii) U. dioica plants show sexual secondary dimorphism in terms of photoinhibition and photo-oxidative stress, but this is only apparent when stress infringed on plants is very severe. [ABSTRACT FROM AUTHOR]

The opportunistic pathogen Pseudomonas aeruginosa PAO1 has a remarkable capacity to adapt to various environments and to survive with limited nutrients. Here, we report the discovery and characterization of a novel small non-coding RNA: NrsZ (nitrogen-regulated sRNA). We show that under nitrogen limitation, NrsZ is induced by the NtrB/ C two-component system, an important regulator of nitrogen assimilation and P. aeruginosa's swarming motility, in concert with the alternative sigma factor RpoN. Furthermore, we demonstrate that NrsZ modulates P. aeruginosa motility by controlling the production of rhamnolipid surfactants, virulence factors notably needed for swarming motility. This regulation takes place through the post-transcriptional control of rhlA, a gene essential for rhamnolipids synthesis. Interestingly, we also observed that NrsZ is processed in three similar short modules, and that the first short module encompassing the first 60 nucleotides is sufficient for NrsZ regulatory functions. [ABSTRACT FROM AUTHOR]

Some patients with COVID-19 pneumonia develop an associated cytokine storm syndrome that aggravates the pulmonary disease. These patients may benefit of anti-inflammatory treatment. The role of colchicine in hospitalized patients with COVID-19 pneumonia and established hyperinflammation remains unexplored. In a prospective, randomized controlled, observer-blinded endpoint, investigator-initiated trial, 240 hospitalized patients with COVID-19 pneumonia and established hyperinflammation were randomly allocated to receive oral colchicine or not. The primary efficacy outcome measure was a composite of non-invasive mechanical ventilation (CPAP or BiPAP), admission to the intensive care unit, invasive mechanical ventilation requirement or death. The composite primary outcome occurred in 19.3% of the total study population. The composite primary outcome was similar in the two arms (17% in colchicine group vs. 20.8% in the control group; p = 0.533) and the same applied to each of its individual components. Most patients received steroids (98%) and heparin (99%), with similar doses in both groups. In this trial, including adult patients with COVID-19 pneumonia and associated hyperinflammation, no clinical benefit was observed with short-course colchicine treatment beyond standard care regarding the combined outcome measurement of CPAP/BiPAP use, ICU admission, invasive mechanical ventilation or death (Funded by the Community of Madrid, EudraCT Number: 2020-001841-38; 26/04/2020). [ABSTRACT FROM AUTHOR]

The foliar exogenous application of kaolin, a radiation-reflecting inert mineral, has proven to be an effective short-term climate change mitigation strategy for Mediterranean vineyards. In this work, we address the hypothesis that kaolin could improve both the hormonal dynamics and physiological responses of grapevines growing in Douro Region, northern Portugal. For this purpose, the leaf water potential, gas exchange and chlorophyll a fluorescence parameters were monitored, as well as the abscisic acid (ABA) and indole-3-acetic acid (IAA) quantification and immunolocalization were assessed. The study revealed a slight decrease in ABA and an increase in IAA in the kaolin treatment, which in turn were associated with the improvement of physiological performance. A month after spraying, kaolin improves the water potential respectively, 30% and 17% in the predawn and midday periods. Besides, plants treated with kaolin showed higher values of stomatal conductance, net CO 2 assimilation rate and intrinsic water use efficiency. Kaolin also ameliorates the effective PSII efficiency (67%), as well as the maximum quantum efficiency of photosystem II and the photosynthetic electron transport rate (>73%). These results were consistent with the higher photochemical quenching and the lower non-photochemical quenching observed in treated leaves and with the better performance obtained by the JIP test parameters. Physiological and hormonal analysis confirmed that kaolin effectively enhance grapevine summer stress tolerance. [ABSTRACT FROM AUTHOR]

• The validity of photo-oxidative stress markers and stress-related phytohormones as proxies of mortality in a perennial herb was evaluated • The contents of carotenoids were good proxies of mortality risk in non-native populations • Whole-organismal mortality in P. lanceolata can be reflected by stress markers a few months prior to death. • A combination of stress markers is needed, rather than relying on a single proxy of mortality. Oxidative stress and hormonal regulation are hallmarks of a/biotic stress responses in plants. However, little is known about their linkage with whole-organismal mortality in long-lived species. Here, we examined the validity of photo-oxidative stress markers and stress-related phytohormones as predictive proxies of mortality risk in the perennial herb Plantago lanceolata. Capitalizing on its broad ecological niche, we examined photo-oxidative stress markers (Fv/Fm ratio, contents of chlorophylls, carotenoids, and tocochromanols, and the extent of lipid peroxidation) and stress-related phytohormones (ABA, salicylic acid and jasmonates contents) as proxies of mortality in three populations of sub-tropical and Mediterranean habitats: Virginia (VA, U.S.A.), Catalonia (CAT, Spain), and Queensland (QLD, Australia). Stress markers were measured together with the vital rates of survival, growth, and reproduction on a total of 279 individuals. Stress marker data were collected during the summer and death/survival was monitored after two and four months. Whole-organism mortality was similarly high in both sub-tropical non-native populations (ca. 30 % after a drought in VA and QLD), but lower in the native population (ca. 10 % in CAT). The contents of antioxidants (lutein, zeaxanthin, β-carotene) and the de-epoxidation state of the xanthophyll cycle (DPS) were good proxies of mortality risk in VA and QLD. DPS and all carotenoid contents per unit of chlorophyll were lower four months in advance in dead than in alive plants in VA and QLD, thus suggesting reduced photoprotective capacity increased the mortality risk in non-native populations. We show that whole-organismal mortality in P. lanceolata is associated with a reduced capacity to enhance photoprotection under abiotic stress conditions. The validity of various stress markers as predictive proxies of mortality risk is discussed. [ABSTRACT FROM AUTHOR]

El centro de salud Parte Vieja/Alde Zaharra de Donostia- San Sebastián atiende una población de 13.843 ciudadanos de los cuales 2174 son mayores de 75 años (15.6%)Esto nos convierte en uno de los centro con población más envejecida de nuestra comunidad. Estamos ubicados en la Parte Vieja, contamos con muchos turistas y con la existencia de muchas barreras arquitectónicas. Todo ello dificulta el acceso a las personas con problemas de movilidad. Esto nos supone realizar un alto número de domicilios ,tanto a enfermeras como a médicos, y nos hace plantearnos una nueva forma de organizarnos. Para ello ,lo primero en detectarse es una disparidad en la carga asistencial entre los diferentes cupos médicos, existiendo cupos con una alta presión asistencial a domicilio frente a otros con menor presencia en el domicilio;se plantea el formar parejas de cupos (cupo grande/cupo pequeño) permitiendo una distribución más homogénea del trabajo. Se diseña una reestructuración de las agendas para disponer de días con más tiempo para acudir a realizar visitas a domicilio. Este día el otro cupo médico asume mayor actividad de consulta. En nuestro análisis se considera prioritario diferenciar los tiempos de la visita a domicilio en función de la complejidad. se diseñan avisos espontáneos de 20 minutos y avisos programados de 40 minutos. Además organizamos la atención a domicilio urgente realizada por el equipo enfermera-médico que da respuesta a la demanda no demorable. Así se evita interrumpir la agenda de los médicos que están en consulta programada. Este sistema nos permite que pacientes que precisen un mayor seguimiento (pacientes pluripatológicos y pacientes en fase final de la vida) tengan un mayor soporte con dos EAP como referencia asistencial fomentando el trabajo compartido y multidisciplinar para la gestión de pacientes complejos. Es importante la labor que desarrolla el área de atención al paciente en la gestión de las agendas de los profesionales implicados. Resulta clave la comunicación con el paciente y se identifica como un problema la ausencia de información clínica actualizada en el domicilio del paciente, para solventar este problema se diseña un documento escrito al que llamamos "carpeta del paciente". Este documento es en soporte papel y debe ser periódicamente actualizado constando de dos áreas bien diferencias. Una de ella dirigida al profesional y otra al paciente. De forma paralela se diseña un pastillero al que llamamos "kit de rescate paciente crónico". Este se diseña de forma homogénea para todos los pacientes y pueden recurrir a él cuando se lo indican de forma telefónica el profesional sanitario responsable de su seguimiento. Esto le puede permitir al paciente modificar el tratamiento al paciente de forma inmediata evitando su desplazamiento a la oficina de farmacia. Con ello se pretende gestionar de forma más adecuada nuestra actividad en los domicilio y mejorar la documentación clínica en domicilio que permitiría una mejor toma de decisiones cuando el paciente no es atendido por su equipo habitual(emergencias, urgencia a domicilio...). Dispondríamos también de un botiquín de rescate. [ABSTRACT FROM AUTHOR]