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Lutein production by coccomyxa sp. SCCA048 isolated from a heavy metal-polluted river in Sardinia (Italy)
No full textLutein production by coccomyxa sp. SCCA048 isolated from a heavy metal-polluted river in Sardinia (Italy)
No full textThe unicellular green alga, Coccomyxa sp. SCCA048 was previously isolated scraping the ferrous material deposited on the rocks along the heavy metals-contaminated river 'Rio Irvi' (Arburese mining district, Sardinia, Italy). The kinetics of autotrophic growth and pigment production of the strain in stressing (continuous light) and control cultures (12: 12 light-dark photoperiod) was described. Time course of both cultures reflected typical microbial growth curves. The maximum cell densities (3.1 × 107 and 1.1 × 107 cell/ml, for continuous light and control cultures, respectively) were found at the end of log phase (day 40). However, continuous light conditions accounted for ≅ 280% higher density than control cultures. The specific growth rate (μ) of the microalga during exponential phase in continuous light was 1.5 times higher than that recorded for the control. The pigment profile, characterised by HPLC, was particularly rich in carotenoids, especially lutein (up to 80% of total carotenoids). The algal strain, cultivated in continuous light, showed high intracellular contents of lutein (0.34 pg/cell) at the beginning of the exponential phase. In addition, lutein cell content, at maximum growth, was higher than those reported in literature for others carotenogenic strains of Coccomyxa. Pigment production by control cultures was always much lower. These data suggested that the microalga cultivated under conditions of stressing light might have potential for the large-scale production of antioxidant carotenoids
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
Potential extinction of Antarctic endemic fungal species as consequence of Global Warming
No full textCryomyces spp. are fungi adapted to the harsh conditions of the McMurdo Dry Valleys in the Antarctic. The structure of their cell wall is one of the main factors for their uncommon ability to survive external stressors. The cells are, in fact, embedded in a thick and strongly melanised cell wall encrusted with black rigid plaques giving a supplementary protection and making them practically impregnable and refractory even to commercial enzymes including chitinases and glucanases. The Antarctic fungus Lecanicillium muscarium CCFEE 5003, able to produce an arsenal of lytic enzymes, including chitinases and glucanases, is known for its ability to degrade the cell walls of different food spoiling and opportunistic fungi as well as plant pathogenic Oomycota. Active cells of Cryomyces spp. were cultivated in dual culture with the mycoparasitic fungus both in liquid and solid media. Light microscope observations revealed that the cell walls of Cryomyces were heavily decayed. This resulted in the release of protoplasts. Hyphae penetration was evident with both scanning and transmission electron microscope observations. Due to its ecological amplitude (i.e. temperature growth range 0–28 °C), the parasitic fungus could easily expand its area of distribution as a consequence of global warming by invading new areas towards the interior of the continent. The establishment of interactions with organisms living at present in border ecosystems may lead to extinction of extremely specialized and poorly competitive entitie
Efficienza delle bioconversioni di acque di vegetazione in fase omogenea ed eterogenea sul rilascio di esoenzimi
No full textVariations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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