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Alkylglycerols (alkyl-Gro) are ether lipids abundant in the liver of some elasmobranch fish species such as ratfishes and some sharks. Shark liver oil from Centrophorus squamosus (SLO), or alkyl-Gro mix from this source, have several in vivo biological activities including stimulation of hematopoiesis and immunological defences, sperm quality improvement, or anti-tumor and anti-metastasis activities. Several mechanisms are suggested for these multiple activities, resulting from incorporation of alkyl-Gro into membrane phospholipids, and lipid signaling interactions. Natural alkyl-Gro mix from SLO contains several alkyl-Gro, varying by chain length and unsaturation. Six prominent constituents of natural alkyl-Gro mix, namely 12:0, 14:0, 16:0, 18:0, 16:1 n-7, and 18:1 n-9 alkyl-Gro, were synthesized and tested for anti-tumor and anti-metastatic activities on a model of grafted tumor in mice (3LL cells). 16:1 and 18:1 alkyl-Gro showed strong activity in reducing lung metastasis number, while saturated alkyl- Gro had weaker (16:0) or no (12:0, 14:0, 18:0) effect. Multiple compounds and mechanisms are probably involved in the multiple activities of natural alkyl-Gro.  相似文献   
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The search for novel compounds of marine origin has increased in the last decades for their application in various areas such as pharmaceutical, human or animal nutrition, cosmetics or bioenergy. In this context of blue technology development, microalgae are of particular interest due to their immense biodiversity and their relatively simple growth needs. In this review, we discuss about the promising use of microalgae and microalgal compounds as sources of natural antibiotics against human pathogens but also about their potential to limit microbial infections in aquaculture. An alternative to conventional antibiotics is needed as the microbial resistance to these drugs is increasing in humans and animals. Furthermore, using natural antibiotics for livestock could meet the consumer demand to avoid chemicals in food, would support a sustainable aquaculture and present the advantage of being environmentally friendly. Using natural and renewable microalgal compounds is still in its early days, but considering the important research development and rapid improvement in culture, extraction and purification processes, the valorization of microalgae will surely extend in the future.  相似文献   
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Effects of age and intensity of urbanization on farmland bird communities   总被引:1,自引:0,他引:1  
Urban sprawl is now occurring worldwide and considered as a major large-scale perturbation on ecosystems. Consequently, urban territory is replacing other habitats such as agricultural areas. As farmland biotic communities are already reported to be declining, it seems necessary to assess the urbanization impact on them. We conducted a bird survey on 92 plots of 1 × 1 km chosen after stratification on the proportion of urban area and farmland habitat (either 0%, 25%, 50%, 75%), focusing on farmland habitat. Two aspects of urbanization were studied: its intensity and its age. We found that farmland bird species richness did not vary with increasing proportion of urbanized habitat. Non-farmland bird species richness increased from 0% to 25% classes and was constant for other classes. No effect of the urbanization age on farmland bird species richness was found, whereas a positive one was found on the non-farmland birds’ species richness. Abundance of the most specialized farmland birds decreases with urbanization intensity and age. We also found that, the more urbanized and the more recently urbanized the plots, the more similar bird communities. A strong difference in farmland bird’s communities’ compositions was found between 0% and 25% of urbanization, whereas no distinction was found between 50% and 75%. Altogether, our results suggest that to maintain for farmland birds, it is better to add new urban habitat in place where it already exist, rather than to spread it in small lots throughout the landscape.  相似文献   
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Despite growing literature supporting the importance of home gardens (HG) as biodiversity hotspots, knowledge of patterns of their contribution to conservation of threatened species and crop wild relatives (CWR) across climate and culture in Africa is still limited. This investigation was conducted across three climatic zones to assess the floristic diversity of home gardens and the extent to which they contribute to conservation of threatened species and CWR. Overall, 240 home gardens were sampled and their floristic diversity assessed. The ecological importance of recorded species was determined per climatic zone using the importance value index (IVI). A cluster analysis was performed to group the species according to their IVI-values and a principal component analysis helped to identify the most important species. 285 species were inventoried throughout the study area. Home garden species’ diversity globally declined from the drier to the wetter zone but was highest in the transition zone. The average number of species found per HG was 10.1 and varied weakly across zones (9.07, Guineo-Congolean zone; 10.77, Sudano-Guinean zone; and 10.53, Sudanian zone). The most important home gardens species in the Sudanian, the Sudano-Guinean and the Guineo-Congolean zones were respectively: Abelmoschus esculentus (L.) Moench and Hibiscus asper Hook.f.; Solanum lycopersicum L. and Zea mays L.; Ipomoea aquatica Forssk. and Senna occidentalis (L.) Link. They were mainly vegetables and used as food and/or medicinal plant species. Twenty CWR and twelve threatened species were recorded and were also mainly used for food and medicinal purposes. Thorough research on socioeconomic factors supporting possession of HG and choice of managed species as well as indigenous management strategies of HG and dynamic of traditional knowledge related to HG may help to deeply assess home gardens’ effectiveness in biodiversity conservation.  相似文献   
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This report describes an ileocecocolic volvulus in a German shepherd dog with risk factors of previous abdominal surgeries and concurrent chronic enteropathy. Contrast-enhanced computed tomography (CT) with multiplanar reformatting was more sensitive than abdominal radiographs or ultrasound to obtain a diagnosis, because of the presence of a “whirl-sign” on CT. A combination of colopexy and cecopexy was succesfully used to treat the patient’s condition.  相似文献   
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