914 research outputs found
Ascorbate differentially regulates elastin and collagen biosynthesis in vascular smooth muscle cells and skin fibroblasts by pretranslational mechanisms
No full textAscorbate contributes to several metabolic processes including efficient hydroxylation of hydroxyproline in elastin, collagen, and proteins with collagenous domains, yet hydroxyproline in elastin has no known function. Prolyl hydroxylation is essential for efficient collagen production; in contrast, ascorbate has been shown to decrease elastin accumulation in vitro and to alter morphology of elastic tissues in vivo, Ascorbate doses that maximally stimulated collagen production (10-200 mu M) antagonized elastin biosynthesis in vascular smooth muscle cells and skin fibroblasts, depending on a com bination of dose and exposure time. Diminished elastin production paralleled reduced elastin mRNA levels, while collagen I and III mRNAs levels increased. We compared the stability of mRNAs for elastin and collagen I with a constitutive gene after ascorbate supplementation or withdrawal. Ascorbate decreased elastin mRNA stability, while collagen I mRNA was stabilized to a much greater extent. Ascorbate withdrawal decreased collagen I mRNA stability markedly (4.9-fold), while elastin mRNA became more stable. Transcription of elastin was reduced 72% by ascorbate exposure. Differential effects of ascorbic acid on collagen I and elastin mRNA abundance result from the combined, marked stabilization of collagen mRNA, the lesser stability of elastin mRNA, and the significant repression of elastin gene transcription
Transforming growth factor-beta reverses a posttranscriptional defect in elastin synthesis in a Cutis Laxa skin fibroblast strain
No full textSkin fibroblasts from two cases of autosomal recessive cutis laxa (CL), having insignificant elastin production and mRNA levels, were challenged with transforming growth factor beta-1 (TGF-beta 1). Elastin production was brought from undetectable values to amounts typical of normal human skin fibroblasts in a dose-dependent fashion. Basic fibroblast growth factor (100 ng/ml) alone or in combination with TGF-beta 1 reduced elastin production and mRNA expression in CL skin fibroblasts more extensively than in normal cells. In situ hybridization showed that these effects were at the transcript level. One of the CL strains was examined in detail. Transcription rates for elastin were similar in normal and CL and unchanged by TGF-beta 1 or TGF-beta 2 (10 ng/ml), while in CL elastin mRNA half-life was increased > 10-fold by TGF-beta 2 and reduced 6-fold after TGF-beta 2 withdrawal, as compared with a control strain. Cycloheximide partially reversed elastin mRNA instability. These data are consistent with a defect in elastin mRNA stability that requires synthesis of labile factors or intact translational machinery, resulting in an extremely low steady state level of mRNA present in this strain of CL. Furthermore, TGF-beta can relieve elastin mRNA instability in at least one CL strain and elastin production defects in both CL strains
Banded fibers in tropoelastin coacervates at physiological temperatures.
No full textTropoelastin was purified from aortas of chicks grown on a beta-aminopropionitrile-containing diet. The preparation could be considered pure following the criteria of amino acid composition and gel electrophoresis. When aqueous solutions of tropoelastin (5 mg/ml) were warmed to 40 degrees C (physiological temperature for chicken) for 10 min, and observed by negative-staining electron microscopy, it revealed the presence of two kinds of ordered structures. One consisted of densely packed parallel filaments with a center-to-center distance of about 5 nm, and the other of banded fibers, 100-150 nm in diameter, with a cross periodicity of about 55 nm. In some areas the fibers appeared to be formed by lateral aggregation of 1.5-2-nm-thick microfilaments. The fibers were similar to those previously obtained with the synthetic polypentapeptide of elastin (Val-Pro-Gly-Val-Gly)n and degradation products of elastin at temperatures much higher than the physiological one. The results indicate that the property of tropoelastin to form ordered structures is intrinsic to some of the polypeptide sequences of the molecule and that hydrophobic forces are involved in the formation of the aggregates
Yield and quality of Corchorus olitoriusbaby leaf grown in a floating system
No full textCorchorus olitorius is mainly cultivated in Africa and is used in the human diet for its nutraceutical proprieties. In this work, C. olitorius was grown in a floating system using a standard (NS100%) or
halved (NS50%) nutrient solution. Yield was evaluated at harvest when plants reached the baby leaf stage. Quality of leaves was estimated by measuring sugars, nitrate, chlorophylls, carotenoids,
polyphenols, and anthocyanins. Yield was similar to other common leafy vegetables cultivated in floating systems. Analytical determinations showed good levels of antioxidant compounds and
sugars. Mineral contents were relevant for Ca, Mg and Fe in comparison with C. olitorius cultivated in soil and other common leafy vegetables. Results showed these plants had healthy characteristics
for human nutrition, in particular for women and children. C. olitorius had a good performance in the floating system with yield ranging from 0.8 to 2.4 kg m−2. Mineral nutrient levels were higher
than in the major leafy vegetables. Nutrient solutions influenced anthocyanin accumulation (+37% in NS50% in spring and +48% in NS50% in summer). Leaf nitrate content was –50% in NS50% at
spring cultivation. The overall quality parameters suggest that C. olitorius can be an optimal candidate for baby leaf production in the fresh cut leafy vegetable industry
I personaggi migranti nel romanzo italiano del XXI secolo. Narrazione omodiegetica e metafinzione,
No full textLa nostra ricerca, comparatistica e interdisciplinare, indaga la rappresentazione letteraria della migrazione nella narrativa italiana contemporanea. Nello specifico, si osservano i significati metafinzionali implicati dalla presenza di elementi autoriflessivi nella narrazione della migrazione in prima persona. L’analisi dei testi verte sul ruolo dell’io-narrante e dei rapporti che instaura con l’autore implicito e il lettore implicito, sull’utilizzo letterario del lessico socio-antropologico e politico della migrazione e sulla percezione che i personaggi migranti hanno di loro stessi e dei luoghi reali e mentali da loro attraversati. I continui rimandi tra realtà e finzione configurano degli spazi metafinzionali all’interno dei quali i personaggi utilizzano la scrittura e la narrazione in maniera introspettiva, restituendo senso alle loro esperienze migratorie e mettendo in dubbio il legame tra codici antropologici e spazi geografici ben definiti.This study is about the literary representation of migration in contemporary Italian fiction. In a comparative and interdisciplinary way, we study metafictional meanings of selfreflexive elements in the first person narration of migration. Our analysis established the role of first person narrator and the relationships with his implicit author and his implicit reader, it focused on literary use of political and sociological vocabulary about migration and it pointed out the migrants perspectives on themselves and on the real and mental places they pass through. The interaction between reality and fiction creates metafictional spaces where the characters write about their migration experience in order to find a sense of it. In this meta fictional space that they created, the migrant characters also discuss the bond between anthropological codes and a specific space in the world
Hyaluronic acid promotes chick embryo fibroblast and chondroblast expression
No full text15-day-chick-embryo fibroblasts and chondroblasts were cultured in the presence of high and low molecular weight exogenous hyaluronic acid (HA). Growth range and incorporation of radiolabelled sulphate and proline were determined. HA reduced cell proliferation to about 75% of controls, while incorporation of radiolabelled sulphate and proline was higher in HA-treated cultures of both chondroblasts and fibroblasts. The effect was not due to the polyanionic or polymeric nature of the molecule and appeared to be highly specific for HA
Vegetable production using a simplified hydroponics system inside Cite of death (Cairo)
No full textThis research work was performed in the poorest urban area of Cairo (Egypt) in a slum area called Al-Quarafa.
The aim was to develop and evaluate a simplified hydroponics system (HS) to grow vegetables for the local inhabitants
who live in an extreme status of food unsafety. In the hydroponic growing system the tomato plants were cultivated and
two substrates were compared: peat:perlite (70/30 W/w) and sand:coir (50:50 W/w). This technique guarantees high
levels of production and low contamination by avoiding the use of polluted urban soils which are often common in slum
areas. Macro and microelements in tomato fruits were analysed by ICP-MS. Results showed low concentrations of heavy
metals (Cd, Sr, As, Cr, Mo) with all heavy metals under the levels set by European Community laws. Lack of food safety in
slums is more closely linked with malnutrition than starvation, so it is also important to understand mineral availability
(both micro and macro) and nutritional significance for health. For this reason micro and macro elements (K, Ca, Na, Fe,
Mn, Mg, Cu, Zn) were analysed in the harvested fruits. This study showed that HS is a valid method to grow vegetables in
urban areas to improve food security in Middle East cities
DOUBLE ROLE OF CORCHORUS OLITORIUS (L.) CULTIVATED IN FLOATING SYSTEM: New leafy vegetable for “ready to eat” industry or active food for developing country
No full textC. olitorius is a traditional African leafy vegetable (ALV). It has interesting nutraceutical properties and is widely consumed among the African and South-East Asia populations. It is commonly cultivated through a conventional way: in the open field. Hydroponic cultivation systems optimize production inputs (water - fertilizer), but they also foster the production and the quality yield. Moreover, hydroponic systems improve shelf life and thus reduce food waste.
For this thesis, a floating system cultivation method has been investigated to grow C. olitorius, commercially known as “baby leaf”. The study has focused on two aspects, namely nutrient supply efficiency and shelf life qualities, in order to accelerate the commercialization of C. olitorius within Europe’s leafy vegetable industry. However, both of those improvements were also essential for improving production and quality levels in developing countries. Moreover, the communities which traditionally consumed C. olitorius in their native countries have been increasing in Europe. Likewise, public interest about nutritional and healthy food is rapidly rising worldwide, so promoting the discovery of new, nutritionally valuable food plants such as C. olitorius could be an interesting step forward. For all these reasons, understanding the nutritional shelf-life of vegetables was a crucial claim for meeting customer needs and for boosting innovation in the food industry.
In these previous studies (Chapter 3-4) an Egyptian ecotype of C. olitorius has been used as a gold standard. Two different nutrient solutions have been tested to optimize nutrient need during a one year cultivation cycle: a standard solution nutrient in full, then a second one halved to test differences in the growth and qualities response. The harvested biomass has been evaluated as baby leaf at the fresh-cut industry stage. Several quality parameters have been estimated: sugars (total, reducing and sucrose), nitrate, chlorophyll, carotenoids, polyphenols and anthocyanins (Chapter 4). Plant production was similar to other common leafy vegetables cultivated in floating systems in Europe. Analytical determinations displayed good levels of antioxidant compounds and sugars. Mineral content was relevant for Ca, Mg, and Iron in comparison with other common leafy vegetables (Corn salad, rocket and lettuce). Moreover, C. olitorius, when cultivated using traditional growing systems in literature, showed less nutrient content than C. olitorius cultivated with the floating method, which was an interesting result for bio-fortification in developing countries. Results showed that the plant had healthy characteristics for human nutrition, especially for females and children. High levels of Ca, Mg and Fe, in fact, are very important during pregnancy and childhood. Results obtained from yields and nitrates indicate that this species can be grown with a lower mineral concentration in the nutrient solution without decreasing production and quality. The level of sugars measured was higher than in other traditional leafy vegetables which are usually cultivated via floating systems such as rocket, lettuce and
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spinach. Higher sugar content could have a positive effect on post-harvest storage and could be an important contribution to the human diet. C. olitorius may hence represent a product innovation in the fresh-cut industry in the near future. Moreover, in this thesis, biochemical and physiological differences of several ecotypes of C. olitorius worldwide and their growing behavior were studied. These elements were priority aspects for the food industry in order to introduce the best genotype adapted for growing in a Southern European environment (Chapter 5). However, considering the difficulties involved with introducing a new leafy vegetable, it is important to consider not only agronomic and physiological aspects but also the consumer’s point of view.
These days, the European population is interested in the prevention of chronic disease through food consumption. For this reason, the final part of this thesis planned to test the fresh crude extracts of C. olitorius in order investigate phenolic and terpene composition. Results confirmed the relevant presence of many active compounds such as quercetin, coumarin, vitamin E and terpenes inside C. olitorius leaves (Chapter 6)
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