1,721,050 research outputs found
Serotonergic neurotransmission manipulation for the understanding of brain development and function: Learning from Tph2 genetic models
Full text linkSerotonin (5-hydroxytriptamine; 5-HT) is a fascinating neurotransmitter that thanks to an extensive axonal network is released throughout the entire central nervous system (CNS) and exerts its action on the modulation of a countless number of physiological, behavioral and cognitive processes. In addition, cumulating evidences have linked alteration in 5-HT neurotransmission with the onset of psychiatric and neurodevelopmental disorders, such as depression, autisms and schizophrenia. Nevertheless only 5% of the total body content of serotonin exerts its action in the CNS, while the rest is synthetized and stored in peripheral tissues where it acts as an autacoid. In 2003 it became evident that two distinct isoforms of tryptophan hydroxylase (Tph), the rate-limiting enzyme for the synthesis of serotonin, are selectively expressed in peripheral tissues and in the CNS, with Tph2 as the brain specific isoform. In the present review we describe how the discovery of Tph2 has improved our understanding on the role of serotonergic neurotransmission. We mainly focus on the analysis of animal models generated by genetic manipulation of Tph2, in which the synthesis of brain serotonin was either reduced or disrupted. The consequences of an altered serotonergic neurotransmission on brain development, as well as on physiological and behavioral processes will be assessed. Finally, we report on several association studies that have linked single nucleotide polymorphisms (SNPs) in the human TPH2 gene with behavioral disturbances and neuropsychiatric disorders
Molecular and taxonomic characterization of a endophytic fungus isolated from Helleborus bocconei subsp. intermedius (Ranunculaceae)
Full text linkA non-sporulating fungus was isolated from different organs of Helleborus bocconei subsp. intermedius (Ranunculaceae) endemic to southern Italy and Sicily, known for the traditional use of dried roots in the treatment of lung diseases of cattle and horses.
Molecular characterization of endophytic fungus based on the internal transcribed spacer (ITS) region of the rRNA gene sequences was done. The DNA sequence of full length ITS region of the studied fungus was a 100% match to that of Chaetomium strumarium strain dH 21642 (GenBank accession number JX280851.1). The morphological characters of colony and mycelium of this microfungus are reported here
Functional study of residual iCre activity relevant for split-Cre applications
Full text linkCre-lox system is a major tool in mouse molecular genetics instrumental in promoting somatic recombination to spatiotemporally control transcriptional activation/inhibition in subsets of cells or tissues in vivo. A critical factor behind this system may be represented by the availability of a specific promoter driving Cre expression in the cell subset of interest. Split-Cre recombinase system represents an evolution that circumvents this limitation using split N- and C-terminal domains of Cre recombinase placed under the control of two distinct promoters defining an intersectional domain where functional complementation of Cre protein fragments is obtained. This system is a valuable tool for controlling Cre recombinase activity in a spatially and temporally defined manner based on the assumption that neither N- or C-terminal Cre fragments alone have recombinase activity. However, residual recombinase activity of one of the two fragments can occur leading to confounding experimental results. In this work, we delve into characterizing functional activity of different N-terminal deleted codon-optimized Cre (iCre) isoforms to refine Split-Cre-based technologies, aiming to avoid uncontrolled recombinase events. Given the presence of several methionine residues in the amino acidic iCre sequence, we explored whether these residues could serve as potential translation start sites, resulting in truncated isoforms that might retain recombinase activity. To address this question, we tested in HEK293T cells whether site-specific recombination was retained in progressively amino-terminal deleted iCre isoforms. Our results reveal residual enzymatic activity of most amino-terminal deleted isoforms of iCre whose ATG start codon is located downstream of the commonly used split site. This insight holds significance for future refinements of the widely used Split-Cre system, providing information to avoid false positive results stemming from unwanted activity
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
Variations 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
Lutein 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
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