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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Proteomica e briofite: Applicazioni di questa tecnica alla studio della sintesi delle proteine nei muschi
No full textAntibacterial and Antifungal Properties of Acetonic Extract of Feijoa sellowiana Fruits and Its Effect on Helicobacter pylori Growth.
No full textFeijoa sellowiana Berg. fruit, widely used for human consumption, is well appreciated for its good nutritional characteristics and for its pleasant flavor and aroma. In a prior study we showed that the acetonic extract of F. sellowiana fruit exerts a potent antibacterial activity against some Gram-positive and Gram-negative bacterial strains. To confirm and deepen the study on antimicrobial activities of the fruit, in this article we analyze the same extract for its effectiveness against different kind of bacteria both as American Type Culture Collection standard strains and clinically isolates, the Gram-negative Helicobacter pylori, and three fungal strains (one human pathogen and two phytopathogens). Our aim was also to isolate and define the active component(s) involved in the antibacterial, antifungal, and anti-H. pylori activity of the extract through activity-guided fractionation procedures. This allowed us to identify flavone as the active compound of F. sellowiana fruit. Flavone showed a high antibacterial activity against the nine standard bacterial strains tested and the matched clinically isolated bacterial strains and was significantly more active against H. pylori than metronidazole. Pseudomonas aeruginosa, Proteus mirabilis, and Proteus vulgaris from both standard and clinical sources showed a very high sensitivity to flavone (minimal inhibitory concentration [MIC]=1.95μg/mL for standard strains and 3.9μg/mL for clinical isolates of the three bacteria), showing also good minimal bactericidal concentration values. Among fungi tested, Rhyzoctonia solani was the most sensitive strain to the action of flavone (MIC=62.5μg/mL)
Ultrastructural alterations and HSP 70 induction in elodea canadensis Mich. exposed to heavy metals
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Water pollution causes ultrastructural and functional damages in Pellia neesiana (Gottsche) Limpr.
No full textThe aim of this work is to evaluate the effects of freshwater pollution in the heavily contaminated SarnoRiver (Campania, South Italy), using Pellia neesiana (Pelliaceae Metzgeriales) in order to propose this liver-wort as a potential bioindicator, able to record the effects of water pollution, particularly the one relatedto metal (loid) contamination. Samples of P. neesiana in nylon bags were disposed floating for one weekon the waters of Sarno River in three sites characterised by an increasing pollution. As control, somespecimens were cultured in vitro in Cd- and Pb-added media, at the same pollutants’ levels as mea-sured in the most polluted site. P. neesiana cell ultrastructure was modified and severe alterations wereobserved in chloroplasts from samples exposed in the most polluted site, and Cd- and Pb-cultured sam-ples. Concurrently, a strong increase in the occurrence of Heat shock proteins 70 (HSP70) was detectedin gametophytes following the pollution gradient. In conclusion, ultrastructural damages can be directlyrelated to HSP 70 occurrence in liverwort tissues, and proportional to the degree of pollution present inthe river; thus our study suggests P. neesiana as an affordable bioindicator of freshwaters pollution
EFFETTO DEI METALLI PESANTI SULL' ATTIVITÀ ENZIMATICA DELLA FENILALANINA AMMONIOLIASI (PAL) DI LEMNA MINOR L.
No full textUltrastructural changes and Heat Shock Proteins 70 induced by atmospheric pollution are similar to the effects observed under in vitro heavy metals stress in Conocephalum conicum (Marchantiales - Bryophyta)
No full textChanges in ultrastructure and induction of Heat Shock Proteins 70 have been studied in Conocephalum conicum (Marchantiales) collected in different urban and country sites in Italy. These results were compared to the effects in vitro of exposition to different heavy metals for several days. At urban sites, cellular ultrastructure was modified, and heavy metals could be observed accumulating in cell walls. Simultaneously, a strong increment in Hsp70 was detected, compared with results observed on control specimens. When C.conicum was exposed to heavy metals in vitro, comparable effects as in polluted sites were observed: Cd and Pb accumulated mostly within parenchyma and, within cells, were absorbed to cell walls or concentrated in vacuoles. Moreover, severe alterations were observed in organelles. Concomitantly, a progressive accumulation of Hsp70 was detected following heavy metals exposition. These effects are discussed in order to describe the dose and time-dependent response to heavy metal stress in C.conicum
Alterazioni ultrastrutturali e induzione di HSP 70 in Elodea canadensis Mich. esposta a metalli pesanti
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