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Aphids (Hemiptera: Aphididae) are herbivorous insects which deprive plants of nutrients by feeding on the phloem sap and transmission of plant viruses. In the present study, the susceptibility of selected white-berried grapevine (Vitis spp.) cultivars "Aurora", "Bianca", "Muskat Letni" and "Solaris" to the black bean aphid (Aphis fabae Scop.) and the green peach aphid (Myzus persicae (Sulz.) was evaluated using the Electrical Penetration Graph (EPG) technique. The content of major flavonoids and stilbenoids in grapevine leaves and leaf anatomy parameters that might have affected aphid probing were also analyzed. Based on the success rate in reaching the phloem vessels and feeding on phloem sap, the studied grapevine cultivars can be assigned to various groups of susceptibility. Cultivars "Bianca" and "Muskalt Letni" are susceptible to A. fabae and M. persicae, respectively (aphids reach phloem phase and show short bouts of sap ingestion); "Muskat Letni" shows low susceptibility to A. fabae, while "Aurora" and "Bianca" to M. persicae (only 50% aphids reach phloem phase and no sap ingestion occurs); "Solaris" is resistant to A. fabae and M. persicae (no phloem phase present). Anatomical structure of leaves was similar in all cultivars and no mechanical barriers for aphid probing were observed. However, the content of individual flavonoids and silbenoids differed among cultivars. We hypothesize that the high content of piceid in the leaves of "Solaris" may be responsible for the rejection of this cultivar by both aphid species. The study demonstrated that the risk of the direct damage due to A. fabae and M. persicae feeding on grapevines is low. However, considering the intense aphid probing activity within leaf epidermis and mesophyll, A. fabae and M. persicae may pose a serious threat as vectors of non-persistent and semi-persistent viruses to white-berried grapevines. [ABSTRACT FROM AUTHOR]

The peach-potato aphid Myzus persicae (Sulzer) and the black bean aphid Aphis fabae Scopoli are polyphagous and cosmopolitan hemipterans, therefore they can infest grapevines in all areas of cultivation. Electrical Penetration Graph (EPG) technique was applied to monitor the probing behavior of A. fabae and M. persicae on Vitis amurensis Rupr., Vitis riparia Michaux, and Vitis vinifera L. The content of major flavonoids and stilbenoids in grapevine leaves and epidermal thickness, distance between abaxial leaf surface and phloem, and the simulated shortest pathway from epidermis to phloem that might have affected aphid probing were also analyzed. Aphid probing was limited mainly to non-vascular tissues on the three studied grapevine species. Phloem phase occurred in 32%, 14%, and 6% of A. fabae and in 76%, 39%, and 74% of M. persicae on V. amurensis, V. riparia and V. vinifera, respectively. Phloem phase consisted of only salivation into sieve elements and lasted less than 2.5 minutes on average in all aphids. The time to reach the first phloem phase on grapevines was 5.0 hours in A. fabae and 2.6–3.6 hours in M. persicae. Of the analyzed flavonoids, catechin, epicatechin, and quercetin occurred in all grapevine species, while rutin – in V. amurensis and V. riparia and isorhamnetin only in V. amurensis. Of the analyzed stilbenoids, piceid occurred in all grapevines, resveratrol in V. amurensis and V. vinifera, and ε-viniferin only in V. vinifera. Aphid behavior demonstrated that V. amurensis, V. riparia and V. vinifera are not attractive host plants to A. fabae and M. persicae. It is likely that the content of flavonoids and stilbenoids contributes to the limited susceptibility of the three grapevine species to A. fabae and M. persicae, while the observed slight differences in the anatomical structure of the leaves seem not significant in this context. [ABSTRACT FROM AUTHOR]

Background Numerous studies have demonstrated increased cardiovascular risk in psoriasis. Circulating endothelial cells (CECs) have been proposed as a new marker of endothelial dysfunction that plays an important role in pathogenesis of atherosclerosis. Objective The aim of this study was to compare the number of CECs in psoriatic patients to a control group and to analyze possible correlations between the numbers of CECs and the plasma levels of classical markers of endothelial dysfunction, such as: sICAM-1, sE-selectin and von Willebrand factor (vWF). Methods The number of CECs, identified as CD146 + / CD45- cells, were determined in peripheral blood with using flow cytometry in psoriatic patients ( n = 63) and controls ( n = 31). The plasma levels of: sICAM-1, sE-selectin, vWF were measured with ELISA. The severity of psoriasis was assessed with PASI. Results The number of CECs was significantly increased in psoriatic patients compared with controls ( P < 0.00001) and positively correlated with disease severity (R = 0.360; P = 0.0037). The levels of sICAM-1, sE-selectin and vWF were significantly elevated in psoriatic patients ( P < 0.00001; P < 0.00001; P = 0.00072, respectively). The number of CECs was significantly, positively correlated with the levels of sICAM-1 (R = 0.393; P = 0.0014) and vWF (R = 0.314; P = 0.012) in psoriatic patients. The levels of sICAM-1 and sE-selectin were positively correlated with disease severity (R = 0.356; P = 0.0041 and R = 0.407; P = 0.0009, respectively). Conclusion The increased number of CECs that correlates with disease severity and plasma levels of sICAM-1 and vWF may indicate endothelial dysfunction or injury in patients with psoriasis. [ABSTRACT FROM AUTHOR]

Abstract: Continuous generation of volatile iodine species based on chemical or photochemical oxidation may be further improved using a sequential (photo)chemical vapor generation/pneumatic nebulization/programmable-temperature spray chamber (P)CVG–PN–PTSC system providing the benefits of a temperature-controlled ICP sample introduction technique. Two experimental setups were designed and optimized to obtain the higher sensitivity. In the CVG mode, the sample and the oxidizing solution are continuously pumped and mixed directly before entering a concentric nebulizer placed in the PTSC, while in PCVG mode the sample solution containing 3%v/v acetic acid is on-line exposed to UV radiation before nebulization. A study was conducted to evaluate the performance of a new CVG–PN–PTSC technique for determination of iodine element by ICP-OES. The ICP-OES intensity is enhanced by a factor of up to 12 by prior oxidation of the iodide to volatile species combined with subsequent pneumatic nebulization, presumably because of increased analyte transport efficiency into the plasma. Next, by heating the spray chamber at 40°C, signal intensities were enhanced by a factor of 3 as compared to the results found at room temperature. Furthermore, using an elevated temperature of the spray chamber slightly increased plasma robustness (MgII to MgI line intensity ratio exceeds 10), likely as a result of increased water vapor that improves plasma stability as well as sensitivity. Both systems were optimized in a wide range of chemical and operating parameters. With both CVG and PCVG–PN–PTSC, the slopes of analytical working graphs of ICP-OES are improved by over an order of magnitude for iodine compared to those with a conventional pneumatic nebulization. Generally, for determination of iodine, the technique exhibits a linear dynamic range of 3 orders of magnitude. For iodine, LODs of 11ngmL−1 were achieved in CVG mode and 17ngmL−1 in PCVG mode at 206.15nm. The technique also gave good short-term stabilities below 2% RSD for both modes. Finally, a continuous CVG technique using sodium nitrite exhibits a better analytical performance than the PCVG mode. Quantitative determination of iodide in mineral water is preferentially carried out by the standard addition procedure. The proposed methodologies were validated with determining of trace iodide in simulated seawater in 2% nitric acid standard reference material CRM-SW, giving rise to satisfactory results. [Copyright &y& Elsevier]