557 research outputs found

    Analysis of the effects of an oncogenic stress on the cell cycle in human tumoral cells

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    Although differing only for the last 24 aminoacids, the three major isoforms of p21 Ras (Ha-, Ki- and N \u2013Ras) can trigger alternative pathways of signal transduction, at least in part as a consequence of different post-translational modifications and subcellular localization. Ras mutations are a common event in tumorigenesis. In colorectal carcinomas (CRCs) the mutations affect almost exclusively Ki-Ras, while Ha-Ras mutations are mostly found in bladder carcinomas and N-Ras mutations in leukemia cells. In almost all cases, the genetic alteration is a point mutation in codons 12 or 13, and less frequently in codon 61. By affecting the GTPase activity of the protein, they always lead to a constitutively active protein. However, data obtained in different experimental systems or by analysis of primary and metastatic tumors show that not only mutations of different isoforms of Ras, but also mutations in different codons or different mutations in the same codon of the same isoform of Ras may have diverse biological consequences. To shed more light on the molecular mechanisms responsible for the different effects of Ras mutations, we have obtained stable clones of HT-29 (a human colorectal adenocarcinoma cell line in which the endogenous Ras genes are wild type) transfected with cDNAs codifying Ha-RasG12V, Ki-RasG12V and Ki-RasG13D, under the control of an hormone-inducible promoter. We found that the expression of each of these mutated Ras isoforms induces specific, different effects on cell morphology and growth rate. FACS analysis shows also a differential effect on the cell cycle. H-RasG12V expression, in addition, induces apoptosis, through caspase activation mediated by p53 independent, MEK-1 dependent expression of the CDK inhibitor p21

    The Global Impact of the COVID-19 Pandemic on Individuals’ and Couples’ Sexuality

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    The COVID-19 pandemic and its related restrictions significantly impacted individuals' health, wellbeing, and security. Isolation, limitation of movement, social distancing, and forced cohabiting have had a strong influence on all areas of people's lives as well as on their sexuality. Investigating how the COVID-19 outbreak and its consequences impacted people's sexuality was the primary aim of this review. Particularly, we focused on: (1) the variables associated with the improvement or the deterioration of individuals' and couples' lives during the pandemic; (2) the use of sex as a coping strategy; (3) the impact of COVID-19 outbreak on LGBT people. Results have shown that the worsening of sexual life seems to be related to couples' conflict, emotions and psychological difficulties, being female, being single or away from the partner, being a health care worker, and having children. Moreover, a detrimental effect on sexuality was associated with stress, forced cohabitation, routine, anxiety and worry about the job and the pandemic, feeling partner distance, being unhappy with their partner, and lack of privacy. On the other hand, improvements in sexuality were associated with living happily with a partner, being happy and satisfied with a partner, feeling less stressed and more bored, having more free time, having fewer recreation opportunities, and having minor workload. During the pandemic, there was an increase in using sex toys, pornography consumption, masturbating, and trying sexual experimentations. Among LGBT people, an increase was found in the number of casual sexual partners potentially due to the perceived lower likelihood of transmission through sex. Moreover, the increase in sexual activity may have represented a coping strategy to quarantine-related distress

    Tannin Structural Elucidation and Quantitative P-31 NMR Analysis. 1. Model Compounds

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    Tannins and flavonoids are secondary metabolites of plants that display a wide array of biological activities. This peculiarity is related to the inhibition of extracellular enzymes that occurs through the complexation of peptides by tannins. Not only the nature of these interactions, but more fundamentally also the structure of these heterogeneous polyphenolic molecules are not completely clear. This first paper describes the development of a new analytical method for the structural characterization of tannins on the basis of tannin model compounds employing an in situ labeling of all labile H groups (aliphatic OH, phenolic OH, and carboxylic acids) with a phosphorus reagent. The P-31 NMR analysis of P-31 labeled samples allowed the unprecedented quantitative and qualitative structural characterization of hydrolyzable tannins, proanthocyanidins, and catechin tannin model compounds, forming the foundations for the quantitative structural elucidation of a variety of actual tannin samples described in part 2 of this series

    Green manuring as sustainable management for southern Italy extensive cultivated areas

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    In the extensively-managed agricultural areas of Sicily, rainfall is often so limited that economically effective annual productions are not feasible. Bare fallow, the most extreme dry-farming technique, seems to be, under such conditions, the only suitable strategy. The introduction in these cropping systems of an annual legume to put early into the soil, as an alternative to bare fallow, may represent a technique able not only to prevent soil erosion, but also to improve the low soil organic matter reserves, with a direct benefit on the following yields and on the whole environment. The trial was aimed to verify the bioagronomical and qualitative behaviour of durum wheat managed under different cropping systems. Results, heavily influenced by very low rainfall (320 mm), stressed the extraordinary productive response of durum wheat cultivated after the green manure legume

    The colours of Segesta. Searching for the traces of the lost pigments

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    Many monuments and objects of the ancient civilizations were painted, but unfortunately the pigments are not still present and sometimes only small traces are evident. The analysis of the traces requires a multianalytical approach through the use of non-invasive techniques and only if necessary of a microsampling. Here, the study of the traces of colours found in some architectural elements and findings belonging to the Archeological Park of Segesta (Trapani, Italy) is reported. The traces are identified and characterised via several techniques such as Optical Microscopy, UV-Fluorescence Imaging, Fiber Optical Reflectance Spectroscopy (FORS), X-ray Fluorescence (XRF) and FT-IR Spectroscopy. Various pigments were identified, some of which are no longer clearly visible to the naked eye: hematite, umber, vegetable black and bone black. Despite the small amount of detectable pigment, the performed investigations allowed us to define part of the pictorial palette to imagine and relive the past in one place

    Crop rotation, nitrogen fertilization and genotype effects on durum wheat productive characteristics

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    A field trial was performed in 2000/01 and 2001/02 in the experimental farm “Sparacia” (Cammarata – AG – Sicily) in order to evaluate the qualitative and quantitative response of four varieties of durum wheat when grown after a legume crop (field pea) or in rotation with itself and when submitted to different N-fertilization levels: no fertilization (N0, control), 60 kg ha-1 (N 60, rate advised by the EC n. 2078/92 for the Sicilian territory) and 120 kg ha-1 (N 120, fertilization rate commonly used under the “traditional” cropping technique). In the first trial year, the fertilized trial expressed a better yield performance than the control, but in 2001/02, characterized by severe and prolonged dry periods, the effect of crop rotation and variety was shown to be more important

    Formamide as the main building block in the origin of nucleic acids

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    The simplest molecules grouping the four most common elements of the universe H,C,O and N (with the exception of the biologically inert He) are isocyanate HNCO and formamide H2NCOH. Reasons for the availability of formamide on prebiotic Earth are presented. We review evidence showing that formamide in the presence of largely available catalysts and by moderate heating yields the complete set of nucleic bases necessary for the formation of nucleic acids. Formamide also favours the formation of acyclonucleosides and the phosphorylation and trans-phosphorylation of nucleosides, thus providing a plausible chemical frame for the passage from a simple one-carbon compound to nucleic polymers. Physico-chemical conditions exist in which formamide favours the stability of the phosphoester bonds in nucleic polymers relative to that of the same bonds in monomers. Starting from a formamide-laden environment subject only to the laws of chemistry, a hypothesis is outlined sketching the passage towards an aqueous world in which Darwinian rules apply
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