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51.
52.
Arturo Samuel Gomez-Insuasti Luis Gustavo Rossi Bruno Ramalho Vieira Telma Teresinha Berchielli 《Archives of animal nutrition》2018,72(4):308-320
Soybean oil with different ruminal availability (whole soybeans (WS), soybean oil (SO) and calcium salts (CS)) was used to evaluate the fatty acid (FA) intake, rumen biohydrogenation (BH) and duodenal flow of FA in Nellore steers fed diets with crude glycerine (CG). Eight castrated Nellore steers were fitted with a ruminal and duodenal silicone cannula, and distributed in a double, simultaneous, Latin square 4 × 4 design with four diets and four experimental periods. Concentrates contained ground maize, urea, mineral salts, CG (100 g/kg DM) and soybean products with different availability of soybean oil: (1) no additional fat (CO), (2) WS, (3) SO or (4) CS. Fat supplementation was fixed to obtain 50 g ether extract/kg DM. Experimental treatments had no effect on DM intake, DM duodenal flow or ruminal turnover rate of C:16 FA. However, fat addition increased C:18 and turnover rates of total FA rumen (p < 0.05). CS resulted in lower C:18 turnover rates and lower ruminal BH of monounsaturated and unsaturated FA (UFA) than WS (p < 0.05). SO resulted in a greater duodenal flow of C18:0 (stearic acid), C18:1t-11 (vaccenic acid) and saturated FA than the WS and CS diets (p < 0.05). CS resulted in a higher duodenal flow of C18:3n-3 (linolenic acid) than WS (p < 0.05). The association of CG and calcium salts in Nellore steers was the best nutritional strategy to increase duodenal flow of healthier UFA, which may increase the deposition of these FA in meat. However, SO associated with CG association increased the duodenal flow of vaccenic acid, which is main precursor of endogenous synthesis of conjugated linoleic acids in tissues. 相似文献
53.
José C. Ramalho M. C. Rebelo M. Emília Santos M. Luísa Antunes M. Antonieta Nunes 《Plant and Soil》1995,172(1):87-96
Calcium deficiency was induced in hydroponically grown 1.5-years-old coffee plants with 12–14 pairs of leaves. Calcium was given in the form of Ca(NO3)2: 5, 2.5, 0.1, 0.01 and 0 mM. After 71 days of Ca-treatment root and shoot as well as total biomass were decreased by severe Ca-deficiency. However, a stronger decrease was observed for shoot growth as revealed by the increase in the root/shoot ratio. New leaves were affected showing decreases in the total leaf area and in Leaf Area Duration (LAD). After 91 days of deficiency, leaf protein concentration decreased (by about 45%) in the top leaves while nitrate reductase activity (NRA) and NO3 content showed no significant changes. Total nitrogen and mineral concentrations (P, K, Ca, Mg and Na) were also determined in leaves and roots. With the decrease in calcium concentration in Ca-deficiency conditions, we observed concomitant increases in the concentrations of K+, Mg2+ and Na+ in leaves (maximal changes of 32% for K+, 96% for Mg2+ and 438% for Na+) and in roots (108% for K+, 86% for Mg2+ and 38% for Na+). Accordingly, the ratio between elements changed, including the ratio N/P, showing a non-equilibrium in the balance of nutrients. Significant correlations were obtained between Ca2+ concentration and some photosynthetic parameters. Ca-deficiency conditions would increase the loss of energy as expressed by the rise in aE and decrease the photochemical efficiency, which confirms the importance of this element in the stabilization of chlorophyll and in the maintenance of good photochemical efficiency at PS II level.Abbreviations Chl
Chlorophyll
- Fv/Fm
ratio of variable to maximal fluorescence
- LAD
leaf area duration
- LHC II
light harvesting complex of PS II
- NRA
nitrate reductase activity
- PC
photosynthetic capacity
- PS II
photosystem II
- P680
reaction center of PS II
- qN
non-photochemical quenching
- qE
high-energy dependent quenching
- qp
photochemical quenching
- SLA
specific leaf area 相似文献
54.
Susana A. Gon?alves Diana Macedo Helena Raquel Pedro D. Sim?es Flaviano Giorgini José S. Ramalho Duarte C. Barral Luís Ferreira Moita Tiago Fleming Outeiro 《PLoS genetics》2016,12(4)
Alpha-Synuclein (aSyn) misfolding and aggregation is common in several neurodegenerative diseases, including Parkinson’s disease and dementia with Lewy bodies, which are known as synucleinopathies. Accumulating evidence suggests that secretion and cell-to-cell trafficking of pathological forms of aSyn may explain the typical patterns of disease progression. However, the molecular mechanisms controlling aSyn aggregation and spreading of pathology are still elusive. In order to obtain unbiased information about the molecular regulators of aSyn oligomerization, we performed a microscopy-based large-scale RNAi screen in living cells. Interestingly, we identified nine Rab GTPase and kinase genes that modulated aSyn aggregation, toxicity and levels. From those, Rab8b, Rab11a, Rab13 and Slp5 were able to promote the clearance of aSyn inclusions and rescue aSyn induced toxicity. Furthermore, we found that endocytic recycling and secretion of aSyn was enhanced upon Rab11a and Rab13 expression in cells accumulating aSyn inclusions. Overall, our study resulted in the identification of new molecular players involved in the aggregation, toxicity, and secretion of aSyn, opening novel avenues for our understanding of the molecular basis of synucleinopathies. 相似文献
55.
Carolina Thieleke‐Matos Mafalda Lopes da Silva Laura Cabrita‐Santos Martim D. Portal Inês P. Rodrigues Vanessa Zuzarte‐Luis José S. Ramalho Clare E. Futter Maria M. Mota Duarte C. Barral Miguel C. Seabra 《Cellular microbiology》2016,18(3):437-450
Autophagy plays an important role in the defence against intracellular pathogens. However, some microorganisms can manipulate this host cell pathway to their advantage. In this study, we addressed the role of host cell autophagy during Plasmodium berghei liver infection. We show that vesicles containing the autophagic marker LC3 surround parasites from early time‐points after invasion and throughout infection and colocalize with the parasitophorous vacuole membrane. Moreover, we show that the LC3‐positive vesicles that surround Plasmodium parasites are amphisomes that converge from the endocytic and autophagic pathways, because they contain markers of both pathways. When the host autophagic pathway was inhibited by silencing several of its key regulators such as LC3, Beclin1, Vps34 or Atg5, we observed a reduction in parasite size. We also found that LC3 surrounds parasites in vivo and that parasite load is diminished in a mouse model deficient for autophagy. Together, these results show the importance of the host autophagic pathway for parasite development during the liver stage of Plasmodium infection. 相似文献
56.
Joana D. Amaral Ricardo J. S. Viana Rita M. Ramalho Clifford J. Steer Cec��lia M. P. Rodrigues 《Journal of lipid research》2009,50(9):1721-1734
Bile acids are a group of molecular species of acidic steroids with peculiar physical-chemical and biological characteristics. At high concentrations they become toxic to mammalian cells, and their presence is pertinent in the pathogenesis of several liver diseases and colon cancer. Bile acid cytoxicity has been related to membrane damage, but also to nondetergent effects, such as oxidative stress and apoptosis. Strikingly, hydrophilic ursodeoxycholic acid (UDCA), and its taurine-conjugated form (TUDCA), show profound cytoprotective properties. Indeed, these molecules have been described as potent inhibitors of classic pathways of apoptosis, although their precise mode of action remains to be clarified. UDCA, originally used for cholesterol gallstone dissolution, is currently considered the first choice therapy for several forms of cholestatic syndromes. However, the beneficial effects of both UDCA and TUDCA have been tested in other experimental pathological conditions with deregulated levels of apoptosis, including neurological disorders, such as Alzheimer''s, Parkinson''s, and Huntington''s diseases. Here, we review the role of bile acids in modulating the apoptosis process, emphasizing the anti-apoptotic effects of UDCA and TUDCA, as well as their potential use as novel and alternate therapeutic agents for the treatment of apoptosis-related diseases. 相似文献
57.
58.
Franciélli Cristiane Gruchowski-Woitowicz Cláudia Inês da Silva Mauro Ramalho 《Ecological Entomology》2020,45(4):854-866
1. Generalists are assumed to play a key role in structuring and stabilising animal–plant mutualistic networks. Until now, analyses on the effects of generalists have been based on empirical field data or simulations. The present natural field experiment manipulated the abundance of a generalist and abundant stingless bee [Melipona (Eomelipona) marginata] to determine the effects on the mutualistic network. 2. Networks were generated, and associated metrics were used for comparing replicate plots with and without the insertion of stingless bee nests. 3. Unweighted metrics and the basic qualitative structural pattern of networks (high nestedness, very low modularity and specialisation) was not affected by experimental variation in stingless bee abundance because they exert strong basal effects on the plant–pollinator community under natural conditions of abundance. Still, increased abundance caused significant variation in weighted nestedness and modularity and community-level specialisation. 4. Supporting predictions of neutral models, increased abundance of the stingless bee led to an increase in most of its specific metrics, expressing the expansion of its realised trophic niche. 5. During this process, specialist and other generalist bees were affected in different ways. More plant species became even more dependent on this stingless bee (increased asymmetry). 6. Long-term effects could not be inferred directly from instantaneous values of network metrics. Nonetheless, the increased abundance of the generalist stingless bee may both reduce the local level of ecological specialisation in the short term and affect the spatial distribution of less abundant and/or specialist bee species and plants in the long term. 相似文献
59.
Pizetta Carolina Senhorinho Ramalho Ribeiro William Rafael Ferreira Amanda Lopes da Costa Moura Matheus Bonfim Kenny Pinheiro Patrícia Valle Cabral Glaucia Barbosa Aragão Francisco José Lima 《Plant Cell, Tissue and Organ Culture》2022,148(2):281-291
Plant Cell, Tissue and Organ Culture (PCTOC) - Whitefly (Bemisia tabaci) is a polyphagous insect that causes huge damage in several horticultural crops, including tomato, by sucking nutrients from... 相似文献
60.
Gabriela de Brito Sanchez João Ramalho Ortigão-Farias Monique Gauthier Fanglin Liu Martin Giurfa 《Arthropod-Plant Interactions》2007,1(2):69-76
The advent of the genomic era has opened new doors to understand the fundamental organization of living organisms and has
therefore promoted a fertile field of comparative research that intends to identify similarities and differences between related
and unrelated species at the genomic level. One of the organisms whose genome has been recently decoded is that of the honeybee
Apis mellifera, enabling a direct comparison with another well-studied insect, the fruit fly Drosophila melanogaster. It was reported that the honeybee has only ten gustatory receptors and thus a very poor taste perception compared to Drosophila, which presents 68 gustatory receptors, and the mosquito Anopheles gambiae, which presents 76 gustatory receptors. In this forum article, we discuss the implications of these findings taking into
account previous and new discoveries on honeybee gustation based on behavioral and neurobiological studies by several authors
and us. We conclude that the world of taste of a honeybee might not be as poor as proposed and that further studies should
integrate molecular, neurobiological, behavioral and ecological approaches to better characterize taste perception in bees.
Handling editor: Lars Chittka 相似文献