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51.
Helena M. Amaro Rita Barros Tnia Tavares Raquel Almeida Isabel Sousa Pinto Francisco Xavier Malcata Ana Catarina Guedes 《Marine drugs》2021,19(11)
Bioactive lipidic compounds of microalgae, such as polyunsaturated fatty acids (PUFA) and carotenoids, can avoid or treat oxidation-associated conditions and diseases like inflammation or cancer. This study aimed to assess the bioactive potential of lipidic extracts obtained from Gloeothece sp.–using Generally Recognized as Safe (GRAS) solvents like ethanol, acetone, hexane:isopropanol (3:2) (HI) and ethyl lactate. The bioactive potential of extracts was assessed in terms of antioxidant (ABTS•+, DPPH•, •NO and O2•assays), anti-inflammatory (HRBC membrane stabilization and Cox-2 screening assay), and antitumor capacity (death by TUNEL, and anti-proliferative by BrdU incorporation assay in AGS cancer cells); while its composition was characterized in terms of carotenoids and fatty acids, by HPLC-DAD and GC-FID methods, respectively. Results revealed a chemopreventive potential of the HI extract owing to its ability to: (I) scavenge -NO• radical (IC50, 1258 ± 0.353 µg·mL−1); (II) inhibit 50% of COX-2 expression at 130.2 ± 7.4 µg·mL−1; (III) protect 61.6 ± 9.2% of lysosomes from heat damage, and (IV) induce AGS cell death by 4.2-fold and avoid its proliferation up to 40% in a concentration of 23.2 ± 1.9 µg·mL−1. Hence, Gloeothece sp. extracts, namely HI, were revealed to have the potential to be used for nutraceutical purposes. 相似文献
52.
Cortisol and testosterone accumulation in a low pH recirculating aquaculture system for rainbow trout (Oncorhynchus mykiss)
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Vasco C Mota Catarina I M Martins Ep H Eding Adelino V M Canário Johan A J Verreth 《Aquaculture Research》2017,48(7):3579-3588
Steroids accumulate in recirculating aquaculture system (RAS), although explanatory factors for such accumulation are still poorly explored. This study investigated the effect of water exchange rate and pH in six replicated RAS on the concentration of the stress hormone cortisol in rainbow trout blood plasma and in the holding water and of the sex steroids testosterone, 11‐ketotestosterone (11‐KT) and 17,20β‐dihydroxypregn‐4‐en‐3‐one (17,20β‐P) over a 70‐day experimental period. Three combinations of water exchange rate and pH were used each treatment, with two replications: (i) high water exchange rate (±1700 L kg?1 feed) and neutral pH (±7.3), (ii) low water exchange rate (±500 L kg?1 feed) and neutral pH (±7.3) and (iii) low water exchange rate (±500 L kg?1 feed) and low pH (±5.8). Plasma cortisol concentrations at day 70 were higher (24.4 ± 9.5 ng mL?1) for fish kept at low pH when compared to fish kept at neutral pH (12.0 ± 0.1 and 8.7 ± 0.2 ng mL?1). Water cortisol and testosterone concentrations at day 35 were higher at low pH than at neutral pH, whereas water 11‐KT and 17,20β‐P did not differ among treatments. At day 70, there were no significant differences between low and high pH. These results demonstrate that low pH contributes to increased plasma cortisol concentrations and to its accumulation in water, possibly indicating a stress response to low pH. The higher concentration of testosterone but not of the other sex hormones point to unspecified reproductive effects that need further investigation. 相似文献
53.
Pascual Garcia-Perez Catarina Loureno-Lopes Aurora Silva Antia G. Pereira Maria Fraga-Corral Chao Zhao Jianbo Xiao Jesus Simal-Gandara Miguel A. Prieto 《Marine drugs》2022,20(2)
Brown algae are ubiquitously distributed in the NW coastline of the Iberian Peninsula, where they stand as an underexploited resource. In this study, five solvents were applied to the extraction of pigments from nine brown algae, followed by their determination and quantification by HPLC-DAD. A total of 13 compounds were detected: Six were identified as chlorophylls, six were classified as xanthophylls, and one compound was reported as a carotene. Fucoxanthin was reported in all extracts, which is the most prominent pigment of these algae. Among them, L. saccharina and U. pinnatifida present the highest concentration of fucoxanthin (4.5–4.7 mg∙g−1 dry weight). Ethanol and acetone were revealed as the most efficient solvents for the extraction of pigments, showing a maximal value of 11.9 mg of total pigments per gram of dry alga obtained from the ethanolic extracts of H. elongata, followed by the acetonic extracts of L. ochroleuca. Indeed, ethanol was also revealed as the most efficient solvent according to its high extraction yield along all species evaluated. Our results supply insights into the pigment composition of brown algae, opening new perspectives on their commercial exploitation by food, pharmaceutical, and cosmeceutical industries. 相似文献
54.
Marcelo D. Catarino Catarina Maral Teresa Bonifcio-Lopes Dbora Campos Nuno Mateus Artur M. S. Silva Maria Manuela Pintado Susana M. Cardoso 《Marine drugs》2021,19(7)
Recent studies indicate that plant polyphenols could be pointed as potential prebiotic candidates since they may interact with the gut microbiota, stimulating its growth and the production of metabolites. However, little is known about the fate of brown seaweeds’ phlorotannins during their passage throughout the gastrointestinal tract. This work aimed to evaluate the stability and bioaccessibility of Fucus vesiculosus phlorotannins after being submitted to a simulated digestive process, as well as their possible modulatory effects on gut microbiota and short-chain fatty acids production following a fermentation procedure using fecal inoculates to mimic the conditions of the large intestine. The stability of phlorotannins throughout the gastrointestinal tract was reduced, with a bioaccessibility index between 2 and 14%. Moreover, slight alterations in the growth of certain commensal bacteria were noticed, with Enterococcus spp. being the most enhanced group. Likewise, F. vesiculosus phlorotannins displayed striking capacity to enhance the levels of propionate and butyrate, which are two important short-chain fatty acids known for their role in intestinal homeostasis. In summary, this work provides valuable information regarding the behavior of F. vesiculosus phlorotannins along the gastrointestinal tract, presenting clear evidence that these compounds can positively contribute to the maintenance of a healthy gastrointestinal condition. 相似文献
55.
Evolution by natural selection is driven by the continuous generation of adaptive mutations. We measured the genomic mutation rate that generates beneficial mutations and their effects on fitness in Escherichia coli under conditions in which the effect of competition between lineages carrying different beneficial mutations is minimized. We found a rate on the order of 10(-5) per genome per generation, which is 1000 times as high as previous estimates, and a mean selective advantage of 1%. Such a high rate of adaptive evolution has implications for the evolution of antibiotic resistance and pathogenicity. 相似文献
56.
Catarina I M Martins Johan W Schrama & Johan A J Verreth 《Aquaculture Research》2005,36(15):1509-1516
Individual variation in growth, feed intake and feeding behaviour has been previously recognized in several fish species. However, there is a lack of information regarding the consistency of such individual differences, which is important to understand the probability of a certain individual trait to be inherent, i.e. genetically linked. The goal of this study is to quantify the consistency of individual differences in growth, feed intake/efficiency and feeding behaviour in African catfish Clarias gariepinus (Burchell 1822). Forty‐eight juvenile fish (58.9±0.4 g) were housed individually for 47 days and weighed every second week. The consistency of growth, feed efficiency (residual feed intake (RFI)) and feeding behaviour (total feeding time (TFT)) was determined using repeatability estimates. Fish exhibited pronounced individual variation in growth (CV=52.8%), feed intake (34.3%) and in the TFT (>100%). The repeatability estimates were 0.55 for growth, 0.70 for feed intake, 0.49 for RFI and 0.81 for TFT. Individual differences in growth were mainly explained by individual differences in feed intake (~80%). Individual differences in feeding behaviour contributed to explain differences in feed intake by affecting the RFI. With increasing TFT, the maintenance levels also increased suggesting that slow eaters were less efficient in feed/energy utilization. The results of this study indicate that individual differences in growth, feed intake/efficiency and feeding behaviour are consistent over time and therefore probably inherent. Moreover, this study may have implications on the use of feeding behaviour as a predictor of feed efficiency in juveniles of African catfish. 相似文献
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58.
Catarina Pereira Fernando Caldeira Jorge Mark Irle José Maria Ferreira 《Journal of Wood Science》2006,52(4):318-324
It is already known by the scientific and industrial communities that lignocellulosic substrates are, to a certain extent,
inhibitors of the hydration reaction of cement. The extent to which and how they influence such reactions is still a matter
of debate. Several techniques, such as calorimetry, i.e., the measurement of the heat evolved or obtaining temperature profiles
during the hydration, the determination of extractive contents of lignocellulosic substrates and their relation with the characteristics
of the hydration curves, or even testing of the mechanical properties of the wood-cement composites, have been used in previous
research. This study complements past research using two techniques that have been used in the analysis of cement hydration
but are not usually applied to lignocellulose-cement mixes, namely X-ray diffraction (XRD) and differential thermal analysis
(DTA). The raw materials for this study were three lignocellulosic materials of Portuguese origin: cork (the bark of Quercus suber L.), blue gum (Eucalyptus globulus Labill.), and maritime pine (Pinus pinaster Ait); and Portland cement. The two techniques allowed tracking of the evolution of the main cement constituents during hydration.
It was found that all the lignocellulosic substrates had detrimental effects on cement hydration. The blue gum exhibited the
fastest hydration kinetics in the initial stage of reaction, but was then overtaken by cork, which at the end gave the highest
hydration conversion amongst the three lignocellulosic substrates. Although pine caused the slowest initial hydration kinetics,
with the passage of time its effect approached that of blue gum. At the end of the hydration period, specimens containing
either species had similar quantities of hydration reaction products. The DTA and XRD results were consistent and are in good
agreement with the temperature profiles and compatibility indexes reported in a previous work. 相似文献
59.
Associations between rearing conditions and the risk of culling in dairy cows were studied by survival analysis. Data were collected from 1039 Swedish Red cows, 1029 Swedish Holsteins, and 56 cows of other milk or cross-breeds, representing all female animals born in 109 Swedish herds during 1998. Length of productive life was defined as the number of days from 1st calving to culling. The applied Weibull proportional hazards model included time-independent effects of breed, housing from 3 to 7 months of age, number of housing changes before calving, grazing before 1st calving, herd median age at 1st calving, age at 1st calving, cow housing, herd lactational incidence risk of veterinary-reported clinical mastitis, and the random effect of herd. Time-dependent effects were year, month, the interaction year by month, parity, number of breedings, pregnancy status, the interaction parity by pregnancy status, herd mean milk-production level, relative milk yield within breed-parity, and veterinary-reported clinical mastitis. The lactation was divided into six stages in which pregnancy status was assumed to be known by the farmer and culling could occur. Median productive life time in culled cows was 780 d and 14% of the records were censored due to terminated data collection. An individual calving age of 28.2–30.9 months was associated with the highest culling risk, 1.2-fold higher than calving at ≤25.3 months, whereas the risk decreased almost linearly with a higher herd median age at 1st calving. Housing in slatted pens with >7 calves from 3 to 7 months was associated with a 1.7-fold increase in risk, relative to litter pens. If a cow had changed housing system 4 times before 1st calving it increased the risk of culling 1.4 times, relative to two housing changes. These results show that rearing factors affect the productive life time of dairy cows in Swedish family operations. 相似文献
60.