929 research outputs found

    A review of the biology of calcium phosphate sequestration with special reference to milk

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    In milk, a stable fluid is formed in which sequestered nanoclusters of calcium phosphate are substructures in casein micelles. As a result, calcium and phosphate concentrations in milk can be far in excess of their solubility. Variations of calcium, phosphate and casein concentrations in milks, both within and among species, are mainly due to the formation of the nanocluster complexes. Caseins evolved from tooth and bone proteins well before the evolution of lactation. It has therefore been suggested that the role of caseins in milk is an adaptation of an antecedent function in the control of some aspect of biomineralisation. There is new evidence that nanocluster-type complexes are also present in blood serum and, by implication, in many other closely related biofluids. Because such fluids are stable but nevertheless supersaturated with respect to the bone and tooth mineral hydroxyapatite, they allow soft and mineralised tissues to co-exist in the same organism with relative ease. An appreciable concentration of nanocluster complexes exists in fresh saliva. Such saliva may stabilise tooth mineral and help to repair demineralised lesions. In the extracellular matrix of bone, nanocluster complexes may be involved in directing the amorphous calcium phosphate to intrafibrillar spaces in collagen where they can mature into oriented apatite crystals. Thus, evidence is accumulating that calcium phosphate sequestration by phosphopeptides to form equilibrium complexes, first observed in milk, is more generally important in the control of physiological calcification

    Micromorfoanatomia foliar de cultivares tintas de Vitis vinifera SSP.vinifera (Vitaceae)

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    Aiming to characterize and discriminate between four red grapevine cultivars – ‘Aragonez’ (AR), ‘Cabernet Sauvignon’ (CS), ‘Syrah’ (SY) and ‘Touriga Nacional’ (TN) – grown under Mediterranean field conditions, we studied their leaf micromorphoanatomic characteristics under light (LM) and scanning electron microscopy (SEM). The studied characteristics included those of the epidermis, stomata and hair distribution, and the mesophyll structure. The individual primary leaf area revealed significant differences between cultivars, with the highest value presented by AR and the lowest by CS, while SY and TN gave intermediate values. CS presented a significantly higher leaf specific dry weight value than the other three cultivars, which returned similar values. Under SEM magnification three types of stomata were identified in all the studied genotypes: sunken, at the same level, and raised above the other epidermal cells. Each cultivar displayed different percentages of these types of stomata: the highest raised-above values were observed in AR; TN had the highest same-level values and the lowest sunken ones; CS revealed the highest values for sunken stomata; while SY returned average values for all the types of stomata. Stomatal density was higher in AR and SY and lower in CS and TN. The hairs on the lower surface presented a similar woolly aspect in all the studied cultivars, but the mesophyll structure was quite different: CS presented the highest and AR the lowest values for total thickness of the lamina, thickness of palisade and spongy parenchyma, and length and thickness of upper and lower epidermal cells; the values for these leaf features in TN and SY fell between those for CS and AR. The data suggest that differences in leaf micromorphoanatomy can be used to distinguish between grapevine cultivars. Further studies are needed to confirm whether there is any association between some of these leaf traits – e.g. stomata type and mesophyll structure – and the physiological behaviour observed under field conditions

    Leaf morphoanatomy of four red grapevine cultivars grown under the same terroir

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    XII Congreso Internacional TerroirThis study compare leaf morphoanatomical characteristics of four red cultivars - ‘Touriga Nacional’, ‘Trindadeira’, ‘Cabernet Sauvignon’ and ‘Syrah’ -, grown side by side at the same terroir. The analyzed leaf traits, under light and scanning electron microscopy, showed large variability among genotypes. ‘Trincadeira’ has the biggest single leaf area and ‘Cabernet Sauvignon’ the smallest one. ‘Touriga Nacional’ showed the lowest leaf dry weight and ‘Trincadeira’ the highest one, nonetheless there was no significantly differences in leaf dry mass per area and in leaf density. Leaf dry mass per area was positively correlated with leaf density but showed no correlation with leaf thickness. The French genotypes presented higher thickness of the leaf anatomical traits than the two Portuguese ones. ‘Trincadeira’ showed significantly highest stomata density while the other cultivars showed no significant differences among them. The analyses of the three types of stomata revealed that ‘Trincadeira’ has the lower percentage of raised above and the highest percentage of sunken stomata while ‘Cabernet Sauvignon’ showed the opposite behaviour. The hairs on the lower surface presented a similar woolly aspect in all cultivars. The possible role of leaf morphoanatomical characteristics in determining the cultivars adaptation to abiotic stresses is suggested and discussedinfo:eu-repo/semantics/publishedVersio

    Caracteristicas morfoanatómicas da folha para a determinação da capacidade de adaptação da videira aos stresses abióticos: revisão

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    ReviewWorldwide, there are thousands of Vitis vinifera grape cultivars used for wine production, creating a large morphological, anatomical, physiological and molecular diversity that needs to be further characterised and explored, with a focus on their capacity to withstand biotic and abiotic stresses. This knowledge can then be used to select better adapted genotypes in order to help face the challenges of the expected climate changes in the near future. It will also assist grape growers in choosing the most suitable cultivar(s) for each terroir; with adaptation to drought and heat stresses being a fundamental characteristic. The leaf blade of grapevines is the most exposed organ to abiotic stresses, therefore its study regarding the tolerance to water and heat stress is becoming particularly important, mainly in Mediterranean viticulture. This review focuses on grapevine leaf morphoanatomy - leaf blade form, leaf epidermis characteristics (cuticle, indumentum, pavement cells and stomata) and anatomy of mesophyll - and their adaptation to abiotic stresses. V. vinifera xylem architecture and its adaptation capacity when the grapevine is subjected to water stress is also highlighted since grapevines have been observed to exhibit a large variability in responses to water availability. The hydraulic properties of the petiole, shoot and trunk are also reviewed. Summarising, this paper reviews recent advances related to the adaptation of grapevine leaf morphoanatomical features and hydraulic architecture to abiotic stresses, mainly water and heat stress, induced primarily by an ever-changing global climateinfo:eu-repo/semantics/publishedVersio

    Anatomia da folha de cultivares brancas de videira com distinta origem geográfica

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    This study aims to compare the leaf morphoanatomical characteristics of seven Vitis vinifera subsp. vinifera white cultivars with different geographical origin, grown side by side at the same “terroir”. The leaf morphoanatomical traits analyzed under light and scanning electron microscopy (SEM) showed large variability among genotypes. Significant differences between cultivars were observed in single leaf area, specific leaf area, leaf density and in the thickness of cuticle, upper and lower epidermal cells and mesophyll. Leaf dry mass per area presented a significant positive correlation with leaf density but showed no correlation with leaf thickness, results that can be explained by the quite different mesophyll structure, epidermal cells and cuticle thickness. ‘Alvarinho’, ‘Encruzado’, ‘Macabeu’ and ‘Viosinho’ were the cultivars with the highest thickness of cuticle and mesophyll tissues. Under SEM magnification three types of stomata were identified: sunken, at the same level and raised above, with the same level type presenting the higher percentage in all cultivars. Stomata density presented significant differences between cultivars, with ‘Macabeu’ showing the highest value and ‘Alvarinho’ and ‘Arinto’ the lowest ones. The hairs on the lower surface presented a similar woolly aspect in all cultivars. Calcium oxalate crystals, raphids and druses were visible and widely distributed in the parenchyma tissues. The observed differences in leaf traits among genotypes suggest a major role of leaf anatomy in determining grapevine capacity for coping with different environmental conditionsinfo:eu-repo/semantics/publishedVersio

    In vivo antimicrobial evaluation of an alanine-rich peptide derived from Pleuronectes americanus

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    AbstractIn several organisms, the first barrier against microbial infections consists of antimicrobial peptides (AMPs) which are molecules that act as components of the innate immune system. Recent studies have demonstrated that AMPs can perform various functions in different tissues or physiological conditions. In this view, this study was carried out in order to evaluate the multifunctional activity in vivo of an alanine-rich peptide, known as Pa-MAP, derived from the polar fish Pleuronectes americanus. Pa-MAP was evaluated in intraperitoneally infected mice with a sub-lethal concentration of Escherichia coli at standard concentrations of 1 and 5mgkg−1. At both concentrations, Pa-MAPs exhibited an ability to prevent E. coli infection and increase mice survival, similar to the result observed in mice treated with ampicillin at 2mgkg−1. In addition, mice were monitored for weight loss. The results showed that mice treated with Pa-MAPs at 1mgkg−1 gained 0.8% of body weight during the 72h of experiment. The same was observed with Pa-MAP at 5mgkg−1, which had a gain of 0.5% in body weight during the treatment. Mice treated with ampicillin at 2mgkg−1 show a significant weight loss of 5.6% of body weight. The untreated group exhibited a 5.5% loss of body weight. The immunomodulatory effects were also evaluated by the quantification of IL-10, IL-12, TNF-α, IFN-γ and nitric oxide cytokines in serum, but no immunomodulatory activity was observed. Data presented here suggest that Pa-MAP should be used as a novel antibiotic against infection control

    Bone Mineral Density in Healthy Female Adolescents According to Age, Bone Age and Pubertal Breast Stage

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    This study was designed to evaluate bone mineral density (BMD) in healthy female Brazilian adolescents in five groups looking at chronological age, bone age, and pubertal breast stage, and determining BMD behavior for each classification. Seventy-two healthy female adolescents aged between 10 to 20 incomplete years were divided into five groups and evaluated for calcium intake, weight, height, body mass index (BMI), pubertal breast stage, bone age, and BMD. Bone mass was measured by bone densitometry (DXA) in lumbar spine and proximal femur regions, and the total body. BMI was estimated by Quetelet index. Breast development was assessed by Tanner's criteria and skeletal maturity by bone age. BMD comparison according to chronologic and bone age, and breast development were analyzed by Anova, with Scheffe's test used to find significant differences between groups at P≤0.05. BMD (g·cm(-2)) increased in all studied regions as age advanced, indicating differences from the ages of 13 to 14 years. This group differed to the 10 and 11 to 12 years old groups for lumbar spine BMD (0.865±0.127 vs 0.672±0.082 and 0.689±0.083, respectively) and in girls at pubertal development stage B3, lumbar spine BMD differed from B5 (0.709±0.073 vs 0.936±0.130) and whole body BMD differed from B4 and B5 (0.867±0.056 vs 0.977±0.086 and 1.040±0.080, respectively). Bone mineralization increased in the B3 breast maturity group, and the critical years for bone mass acquisition were between 13 and 14 years of age for all sites evaluated by densitometry

    Evaluation of the cytotoxicity (HepG2) and chemical composition of polar extracts from the ruderal species Coleostephus myconis (L.) Rchb.f.

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    Coleostephus myconis (L.) Rchb.f. (Asteraceae) is a highly disseminated plant species with ruderal and persistent growth. Owing to its advantageous agronomic properties, C. myconis might have industrial applications. However, this species needs to be comprehensively characterized before any potential use. In a previous study, the phenolic composition and antioxidant activity of different C. myconis tissues were characterized. This investigation was extended to examine the cytotoxic potential of selected plant tissues (flowers and green parts) using a HepG2 cell line by utilizing the lysosomal neutral red uptake assay or mitochondrial (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide assay. In addition, the macronutrients content, lipophilic compounds (fatty acids, tocopherols), and amino acids were also determined. C. myconis flowers were used in the senescence stage, which was previously identified as the stage that presented maximal phenolic content and highest antioxidant activity. In contrast, stems and leaves were employed due to their high biomass proportion. Regarding cytotoxicity, mitochondrial and lysosomal damage was only significant when HepG2 cells were exposed to the highest extract concentrations (stems and leaves, 0.9 mg/ml; senescent flowers, 0.3 mg/ml). Chemically, the senescent flowers were mostly characterized by their high levels of fat, amino acids (especially threonine), oleic acid, ß-, and ?-tocopherol, while stems and leaves contained high concentrations of carbohydrates, linolenic acid, and a-tocopherol. In general, these results provide information regarding the threshold concentrations of C. myconis extracts that might be used in different applications without toxicity hazards.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support to REQUIMTE (PEst-C/EQB/LA0006/2014) and to CIMO (UID/AGR/00690/2013). J.C.M. Barreira, Carla Costa, and Filipa B. Pimentel thank FCT, POPH-QREN, and FSE for their grants (SFRH/BPD/72802/2010, SFRH/BPD/96196/2013 and SFRH/BD/109042/2015, respectively).info:eu-repo/semantics/publishedVersio

    Composition Of ω-3 And ω-6 Fatty Acids In Freeze-dried Chicken Embryo Eggs With Different Days Of Development

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    Fatty acids ω-3 and ω-6 composition and specially DHA were determined in freeze-dried chicken embryo eggs with pre-determined incubation periods. Fertile and embryo eggs presented palmitic (23.18 ± 0.54%), stearic (7.70 ± 0.28%), palmitoleic (3.00 ± 0.19%), oleic (36.28 ± 0.58%), linoleic (22.18 ± 0.34%), linolenic (1.08 ± 0.04%), arachidonic (2.04 ± 0.03%), docosahexaenoic (0.91 ± 0.03%), total ω-3 acids (2.26 ± 0.10%) and total ω-6 acids (24.62 ± 0.33%). There were no significant differences in total contents of ω-3 fatty acids (p=0.1226) between freeze-dried chicken embryo eggs with different incubation periods (3, 5, 7, 9, and 11 days) and fertile freeze-dried chicken eggs (day 0). However, there were significant differences in total medium contents of ω-6 fatty acids (P=0.001). There was also a strong statistical evidence that quadratic model was related with expected values of DHA content (p= 0.0013).472219224Abril, R., Barclay, B., Fatty acid analysis of poultry eggs as methyl esters (1999) Método OT-GCPE, Rev. 3.1, , OmegaTech. Bolder, Co. 24/03/99(1996) Official Methods and Recommended Practices of de American Oil Chemists' Society. 4th Ed., , American Oil Chemists' Society, Champaign IIBragagnolo, N., Turatti, J.M., Evaluation of "light" eggs in Brazil (1999) Associazione Italiana di Avicoltura Scientifica, Instituto di Zootecnia, 2, pp. 177-181. , Paper presented at VIII European Symposium on the Quality of Eggs and Eggs Products, Bologna, ItáliaBeig, D., Garcia, F.C.M., (1986) O Embrião de Galinha, , Campo Grande : UFMS/ Imprensa UniversitáriaCherian, G., Sim, J.S., Net transfer and incorporation of yolk n-3 fatty acids into developing chick embryos (1993) Poultry Science, 72, pp. 98-105Cherian, G., Gopalakrishnan, N., Akiba, Y., Sim, J.S., Effect of maternal dietary n-3 fatty acids on the accretion of long-chain polyunsaturated fatty acids in the tissues of developing chick embryo (1997) Biology of Neonate, 72, pp. 165-174Connor, W.E., Importance of n-3 fatty acids in health and disease (2000) American Journal of Clinical Nutritional, 71 (SUPPL.), pp. 171S-175SFarkas, K., Noble, R.C., Speake, B.K., Development changes in the levels of molecular species of triacylglicerol that contain docosahexaenoic acid in adipose tissue of chick embryo (1996) Comparative Biochemistry and Physiology B-Biochemistry and Molecular Biology, 115, pp. 1-6Ferrier, L.K., Gaston, L.J., Leeson, S., Squires, J., Weaver, B.J., Holub, B.J., α-linolenic acid - and docosahexaenoic acid - enriched eggs from hens fed flaxseed: Influence on blood lipids and platelet phospholipid fatty acids in human (1995) The American Journal of Clinical Nutrition, 62, pp. 81-86Lin, D.S., Connor, W.E., Anderson, G.J., The incorporation of n-3 and n-6 essential fatty acids into chicken embryo from eggs yolks having vastly different fatty acid compositions (1991) Pediatric Research, 29, pp. 601-605Maldjian, A., Falkas, K., Noble, R.C., Cocchi, M., Speake, B.K., The transfer of docosahexaenoic acid from the yolk to the tissues of chicken embryo (1995) Biochimica et Biophysica Acta, 1258, pp. 81-99Nettleton, J.A., (1995) Omega-3 Fatty Acids and Health, , Chapman and Hall, New YorkNoble, R.C., Cocchi, M., Lipid metabolism and the neonatal chicken (1990) Prog. Lipid Res., 29, pp. 107-140Park, Y.K., Koo, M.H., Carvalho, P.O., Recentes Progresses dos Alimentos Funcionais (1997) Bol. SBCTA, 31Salatin, J., Pastured poultry profits (1993) Polyface Swoope, , VirginiaSpeake, B.K., Murray, A.M.B., Noble, R.C., Transport and transformations of yolk lipids during development of avian embryo (1998) Prog. Lipid Res., 37, pp. 1-32Stadelman, W.J., Pratt, D.E., Factors influencing composition the hen's egg (1989) World's Poultry Science Journal, 45, pp. 247-261Thapon, J.L., Bourgeois, C.M., L'oeuf et les ovoproduits (1994) Lavoisier -Technique et Documentation, , ParisVieira, S., Hoffmann, R., Estatísitica experimental (1989) Atlas, , São Paul
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