Effetti delle variazioni di intensita e di distribuzione spaziale dell'aerosol marino sui popolamenti vegetali di dune costiere

La comprensione dei processi ecologici e dei loro effetti sulla struttura dei popolamenti è di primaria importanza nell'ecologia moderna. Di particolare interesse è l'identificazione delle scale a cui si concentra prevalentemente l'azione dei diversi processi, nonché la comprensione di come la variabilità dei processi influisca sulla varianza dei popolamenti. Questa tesi si propone di esaminare sperimentalmente gli effetti dell'aerosol marino sulla struttura dei popolamenti vegetali delle dune costiere. Lo studio è stato condotto su un tratto di dune costiere all’interno del parco regionale di S. Rossore (PI). Uno studio pilota è stato condotto per stimare l’intensità e la distribuzione spaziale con cui l'aerosol raggiunge le dune costiere in senso parallelo alla linea di costa. Nel mese di aprile 2009 è stato allestito l'esperimento manipolativo: le unità sperimentali sono rappresentate da 10 transetti lunghi 64m paralleli alla linea di costa. L'applicazione di aerosol marino è stata eseguita secondo un disegno sperimentale in cui il fattore “intensità” (alta, bassa) ed il fattore “distribuzione spaziale” (omogenea, eterogenea) sono incrociati in maniera ortogonale. Ciascuna combinazione dei livelli è stata replicata in due transetti; due transetti sono stati usati come controlli non manipolati. I trattamenti sono stati ripetuti con cadenza mensile. Sono stati effettuati campionamenti fotografici nei mesi di aprile, giugno e settembre 2009. Le variabili di risposta sono costituite dal numero di specie, dai valori di copertura percentuale per ciascuna specie vegetale e di copertura complessiva in ciascun quadrato sperimentale. I dati ottenuti sono stati analizzati attraverso l’analisi spettrale; le condizioni sperimentali sono state confrontate analizzando le rispettive densità spettrali per mezzo di analisi multilivello gerarchizzata. I risultati dello studio pilota indicano che lo spettro di variabilità con cui l'aerosol si deposita sulle dune varia in base alle condizioni del vento e delle onde. I risultati dell'esperimento manipolativo indicano che l'esposizione ad aerosol con elevata intensità induce un aumento di autocorrelazione nelle variabili di risposta e una ripartizione della loro varianza soprattutto alle scale maggiori; l'esposizione ad aerosol con distribuzione eterogenea nello spazio induce invece una riduzione dell'autocorrelazione nelle variabili di risposta ed una più uniforme ripartizione della loro varianza complessiva alle diverse scale

Pollination ecology and circadian patterns of inflorescence opening of the Madagascan climber Dalechampia aff. bernieri (Euphorbiaceae)

Floral morphology often directly influences interactions with pollinators, but less is known about the role of extrafloral structures. We studied the relationship between bract motility, floral structural specialization and pollination in Dalechampia aff. bernieri, an endemic Madagascan species with floral structures indicating specialized buzz-pollination.Wemeasured circadian bract angles in 47 inflorescences from 11 plants of D. aff. bernieri; in addition, we recorded any flower-visiting insects observed. The inflorescences hadmotile bracts with mean angles varying from about 50° at 00h00 to about 90° at 10h45. They were visited by buzz-pollinating Nomia viridilimbata bees (Halictidae), but also by non-buzz-pollinating Liotrigona bees (Apidae). The temporal pattern of bractmotility observed in D. aff. bernieri may represent an extra-floral specialization to reduce visitation by non-pollinating visitors while maximizing visitation by diurnal buzz-pollinating bees

Synergistic antitumour activity of RAF265 and ZSTK474 on human TT medullary thyroid cancer cells

Medullary thyroid cancer (MTC) is an aggressive malignancy responsible for up to 14% of all thyroid cancer-related deaths. It is characterized by point mutations in the rearranged during transfection (RET) proto-oncogene. The activated RET kinase is known to signal via extracellular signal regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K), leading to enhanced proliferation and resistance to apoptosis. In the present work, we have investigated the effect of two serine/threonine-protein kinase B-Raf (BRAF) inhibitors (RAF265 and SB590885), and a PI3K inhibitor (ZSTK474), on RET-mediated signalling and proliferation in a MTC cell line (TT cells) harbouring the RETC634W activating mutation. The effects of the inhibitors on VEGFR2, PI3K/Akt and mitogen-activated protein kinases signalling pathways, cell cycle, apoptosis and calcitonin production were also investigated. Only the RAF265+ ZSTK474 combination synergistically reduced the viability of treated cells. We observed a strong decrease in phosphorylated VEGFR2 for RAF265+ ZSTK474 and a signal reduction in activated Akt for ZSTK474. The activated ERK signal also decreased after RAF265 and RAF265+ ZSTK474 treatments. Alone and in combination with ZSTK474, RAF265 induced a sustained increase in necrosis. Only RAF265, alone and combined with ZSTK474, prompted a significant drop in calcitonin production. Combination therapy using RAF265 and ZSTK47 proved effective in MTC, demonstrating a cytotoxic effect. As the two inhibitors have been successfully tested individually in clinical trials on other human cancers, our preclinical data support the feasibility of their combined use in aggressive MTC

Mechanisms of endothelial cell dysfunction in cystic fibrosis

Although cystic fibrosis (CF) patients exhibit signs of endothelial perturbation, the functions of the cystic fibrosis conductance regulator (CFTR) in vascular endothelial cells (EC) are poorly defined. We sought to uncover biological activities of endothelial CFTR, relevant for vascular homeostasis and inflammation. We examined cells from human umbilical cords (HUVEC) and pulmonary artery isolated from non-cystic fibrosis (PAEC) and CF human lungs (CF-PAEC), under static conditions or physiological shear. CFTR activity, clearly detected in HUVEC and PAEC, was markedly reduced in CF-PAEC. CFTR blockade increased endothelial permeability to macromolecules and reduced trans‑endothelial electrical resistance (TEER). Consistent with this, CF-PAEC displayed lower TEER compared to PAEC. Under shear, CFTR blockade reduced VE-cadherin and p120 catenin membrane expression and triggered the formation of paxillin- and vinculin-enriched membrane blebs that evolved in shrinking of the cell body and disruption of cell-cell contacts. These changes were accompanied by enhanced release of microvesicles, which displayed reduced capability to stimulate proliferation in recipient EC. CFTR blockade also suppressed insulin-induced NO generation by EC, likely by inhibiting eNOS and AKT phosphorylation, whereas it enhanced IL-8 release. Remarkably, phosphodiesterase inhibitors in combination with a β2 adrenergic receptor agonist corrected functional and morphological changes triggered by CFTR dysfunction in EC. Our results uncover regulatory functions of CFTR in EC, suggesting a physiological role of CFTR in the maintenance EC homeostasis and its involvement in pathogenetic aspects of CF. Moreover, our findings open avenues for novel pharmacology to control endothelial dysfunction and its consequences in CF

Pollination ecology and circadian patterns of inflorescence opening of the Madagascan climber Dalechampia aff. bernieri (Euphorbiaceae)

Floral morphology often directly influences interactions with pollinators, but less is known about the role of extrafloral structures. We studied the relationship between bract motility, floral structural specialization and pollination in Dalechampia aff. bernieri, an endemic Madagascan species with floral structures indicating specialized buzz-pollination. We measured circadian bract angles in 47 inflorescences from 11 plants of D. aff. bernieri; in addition, we recorded any flower-visiting insects observed. The inflorescences had motile bracts with mean angles varying from ~50° at 00h00 to ~90° at 10h45. They were visited by buzz-pollinating Nomia viridilimbata bees (Halictidae), but also by non-buzz-pollinating Liotrigona bees (Apidae). The temporal pattern of bract motility observed in D. aff. bernieri may represent an extra-floral specialization to reduce visitation by non-pollinating visitors while maximizing visitation by diurnal buzz-pollinating bee

Structural and electrical properties of annealed Ge2Sb2Te5 films grown on flexible polyimide

The morphological, structural, and electrical properties of as-grown and annealed Ge2Sb2Te5 (GST) layers, deposited by RF-sputtering on flexible polyimide, were studied by means of optical microscopy, atomic force microscopy, X-ray diffraction, Raman spectroscopy, and electrical characterization. The X-ray diffraction annealing experiments showed the structural transformation of GST layers from the as-grown amorphous state into their crystalline cubic and trigonal phases. The onset of crystallization of the GST films was inferred at about 140 degrees C. The vibrational properties of the crystalline GST layers were investigated via Raman spectroscopy with mode assignment in agreement with previous works on GST films grown on rigid substrates. The electrical characterization revealed a good homogeneity of the amorphous and crystalline trigonal GST with an electrical resistance contrast of 8 x 10(6)

CFTR Modulation Reduces SARS-CoV-2 Infection in Human Bronchial Epithelial Cells

People with cystic fibrosis should be considered at increased risk of developing severe symptoms of COVID-19. Strikingly, a broad array of evidence shows reduced spread of SARS-CoV-2 in these subjects, suggesting a potential role for CFTR in the regulation of SARS-CoV-2 infection/replication. Here, we analyzed SARS-CoV-2 replication in wild-type and CFTR-modified human bronchial epithelial cell lines and primary cells to investigate SARS-CoV-2 infection in people with cystic fibrosis. Both immortalized and primary human bronchial epithelial cells expressing wt or F508del-CFTR along with CRISPR/Cas9 CFTR-ablated clones were infected with SARS-CoV-2 and samples were harvested before and from 24 to 72 h post-infection. CFTR function was also inhibited in wt-CFTR cells with the CFTR-specific inhibitor IOWH-032 and partially restored in F508del-CFTR cells with a combination of CFTR modulators (VX-661+VX-445). Viral load was evaluated by real-time RT-PCR in both supernatant and cell extracts, and ACE-2 expression was analyzed by both western blotting and flow cytometry. SARS-CoV-2 replication was reduced in CFTR-modified bronchial cells compared with wild-type cell lines. No major difference in ACE-2 expression was detected before infection between wild-type and CFTR-modified cells, while a higher expression in wild-type compared to CFTR-modified cells was detectable at 72 h post-infection. Furthermore, inhibition of CFTR channel function elicited significant inhibition of viral replication in cells with wt-CFTR, and correction of CFTR function in F508del-CFTR cells increased the release of SARS-CoV-2 viral particles. Our study provides evidence that CFTR expression/function is involved in the regulation of SARS-CoV-2 replication, thus providing novel insights into the role of CFTR in SARS-CoV-2 infection and the development of therapeutic strategies for COVID-19

Head-to-head comparison of plasma cTnI concentration values measured with three high-sensitivity methods in a large Italian population of healthy volunteers and patients admitted to emergency department with acute coronary syndrome: A multi-center study

Abstract Background The study aim is to compare cTnI values measured with three high-sensitivity (hs) methods in apparently healthy volunteers and patients admitted to emergency department (ED) with acute coronary syndrome enrolled in a large multicentre study. Methods Heparinized plasma samples were collected from 1511 apparently healthy subjects from 8 Italian clinical institutions (mean age: 51.5 years, SD: 14.1 years, range: 18–65 years, F/M ratio:0.95). All volunteers denied chronic or acute diseases and had normal values of routine laboratory tests. Moreover, 1322 heparinized plasma sample were also collected by 9 Italian clinical institutions from patients admitted to ED with clinical symptoms typical of acute coronary syndrome. The reference study laboratory assayed all plasma samples with three hs-methods: Architect hs-cTnI, Access hs-cTnI and ADVIA Centaur XPT methods. Principal Component Analysis (PCA) was also used to analyze the between-method differences among hs-cTnI assays. Results On average, a between-method difference of 31.2% CV was found among the results of hs-cTnI immunoassays. ADVIA Centaur XPT method measured higher cTnI values than Architect and Access methods. Moreover, 99th percentile URL values depended not only on age and sex of reference population, but also on the statistical approach used for calculation (robust non-parametric vs bootstrap). Conclusions Due to differences in concentrations and reference values, clinicians should be advised that plasma samples of the same patient should be measured for cTnI assay in the same laboratory. Specific clinical studies are needed to establish the most appropriate statistical approach to calculate the 99th percentile URL values for hs-cTnI methods