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排序方式: 共有390条查询结果,搜索用时 15 毫秒
41.
Ali Jamshidparvar Faramin Javandel Alireza Seidavi Francisco Peña Blanco Andrés L. Martínez Marín Carmen Avilés Ramírez Estrella Agüera Buendía Nieves Núñez-Sánchez 《Environmental science and pollution research international》2017,24(30):23571-23577
Increasing levels of Heracleum persicum (golpar) in drinking water were studied in broilers. Two hundred and forty-one-day-old male chickens were allocated to one of six treatments: control, without added phytogenics nor probiotics in drinking water, and probiotics at recommended manufacturer’s level (P) or 1.0, 1.5, 2.0, and 2.5 ml/l of golpar extract solution (G1, G1.5, G2, and G2.5 treatments, respectively) in drinking water. As a result of this study, no linear or quadratic trends in the feed intake (FI) and feed conversion rate (FCR) due to golpar supplementation were found. Body weight gain, final body weight, and relative carcass weight showed a positive linear response with increasing levels of golpar supplementation. Neither golpar nor probiotics had effects on the percentages of edible parts of the carcass. Golpar supplementation levels caused a linear negative response of the albumin content in blood plasma, whereas both abdominal fat as percentage of carcass weight and uric acid levels in blood plasma linearly increased. The effects on Ig responses were only observed at 42 days of age and were similar in probiotics and the highest level of golpar supplementation. Based on our results, both probiotics and golpar supplementation could improve broiler performance and immune function. 相似文献
42.
Norma Estrada Carmen Rodríguez-Jaramillo Gerardo Contreras Felipe Ascencio 《Marine Biology》2010,157(6):1401-1415
In general, bivalves are not affected by exposure to toxic dinoflagellates that produce paralyzing shellfish poisons (PSP).
After injection with PSP extracted from the Gymnodinium catenatum, Nodipecten subnodosus is paralyzed, indicating that PSP provokes effects similar to what is observed in vertebrates, including paralysis and metabolic
stress. To investigate the processes involved in poisoning by PSP, lions-paw scallops were injected with gonyautoxin (GTX)
2/3 epimers in the adductor muscle. Mild doses provoked adductor muscle contractions and paralysis, mantle retraction, and
incapacity of shell closure, but scallops gradually recovered in a clear, dose-time recovery pattern. With high doses of GTX
2/3, scallops were permanently paralyzed, and hemocytes in hemolymph were reduced. Surprisingly, under these conditions, scallops
continued normal feeding and did not show any microscopic defect in intestine or gills, but hemocytes infiltrated the adductor
muscle and abnormal vitellogenesis and mantle melanization occurred. Paralysis stress was accompanied by negative scallop
responses, based on visible effects, generation of nitric oxide, lipid peroxidation, and changes in antioxidant and hydrolytic
enzymes in hemocytes and tissues. These data can be used to understand potential side effects of PSP in bivalves. 相似文献
43.
Citizen science networks in natural history and the collective validation of biodiversity data
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Biodiversity data are in increasing demand to inform policy and management. A substantial portion of these data is generated in citizen science networks. To ensure the quality of biodiversity data, standards and criteria for validation have been put in place. We used interviews and document analysis from the United Kingdom and The Netherlands to examine how data validation serves as a point of connection between the diverse people and practices in natural history citizen science networks. We found that rather than a unidirectional imposition of standards, validation was performed collectively. Specifically, it was enacted in ongoing circulations of biodiversity records between recorders and validators as they jointly negotiated the biodiversity that was observed and the validity of the records. These collective validation practices contributed to the citizen science character or natural history networks and tied these networks together. However, when biodiversity records were included in biodiversity‐information initiatives on different policy levels and scales, the circulation of records diminished. These initiatives took on a more extractive mode of data use. Validation ceased to be collective with important consequences for the natural history networks involved and citizen science more generally. 相似文献
44.
Gender aspects in the management of water 总被引:1,自引:0,他引:1
Water resources increasingly need to meet the demands and needs of different sectors and to be protected against deteriorating quantity and quality. This paper discusses the different interests of men and women in the use of water resources, and what effects the neglect of female interests in particular, has on development. The authors stress that besides class and ethnic differences, the different interests of men and women also play a role in the cross-sectoral management of water resources. Water pricing, property rights and management structures are three key aspects where a gender approach is required. In the management of water resources in smaller catchment areas, several instruments for a gender approach have been developed. Discussed are gender specific participatory research, planning and tools, gender in management organizations and task divisions and involvement of multidisciplinary teams with a gender orientation. 相似文献
45.
46.
Comparisons were made of metal concentrations in water and sediment with those in the muscle and livers of three species of fish caught in four seawater reservoirs (two in the Odiel estuary and two in the Bay of Cádiz). The concentrations of a large number of metals in the water, sediment and fish were higher in the Odiel reservoirs than in those in Cádiz. We found high metal-enrichment factors in the livers as compared to muscle (over 100 for Fe and Cu and around 5 for Zn, Ni, Cd and Pb). The three fish species showed differences in metal content. For example, eels accumulated more metals in muscle and grey mullet in the liver. The metal levels found in muscle in the three species were below the legal limits for human consumption, although Cu in the liver was above the limit in the three species taken from the Odiel reservoirs, and Zn levels in liver were over the maximum in eels from one of the Odiel marshes. Significant correlations (p<0.05) were obtained for the levels of numerous metals in water, sediment and fish. 相似文献
47.
Azotobacter vinelandii UWD, ATCC 53799, an engineered strain derived from Azotobacter vinelandii UW was used in the poly(ethylene glycol) (PEG)-modulated synthesis of poly(-hydroxybutyrate) (PHB). To the best of our knowledge, this is the first report on modulating the production of PHB by amending the fermentation broth with PEG using A. vinelandii UWD. It was determined that A. vinelandii UWD is prone to back-mutation to the parent strain; hence fermentation experiments require the use of the antibiotic rifampicin. Diethylene glycol (DEG) and PEGs with molecular weights of 400, 2000, and 3400 Da and pentaerythritol ethoxylate (PEE) were used in the modulated fermentation experiments in a concentration of 2% (w/v). The molecular weight of the resulting polymers was reduced by up to 78%. No impact on the productivity of the strain was observed. Spectroscopic evidence showed that PEG-modulated synthesis resulted in the covalent attachment of the ethylene glycol moiety only when a small molecule, DEG, was used. PEGs had the same effects on the polymer formation in terms of molecular weight reduction as DEG, but no spectroscopic evidence was found for the formation of a covalent linkage between PHB and higher molecular weight PEGs. 相似文献
48.
Carmen A. Lebrón Timothy McHale Robroy Young Dale Williams Matthew G. Bogaart David W. Major Michaye L. McMaster Ian Tasker Naji Akladiss 《补救:环境净化治理成本、技术与工艺杂志》2007,17(2):5-17
An Interstate Technology and Regulatory Council (ITRC) forum was recently held that focused on six case studies in which bioremediation of dense nonaqueous‐phase liquids (DNAPLs) was performed; the objective was to demonstrate that there is credible evidence for bioremediation as a viable environmental remediation technology. The first two case studies from the forum have been previously published; this third case study involves a pilot‐scale demonstration that investigated the effects of biological activity on enhancing dissolution of an emplaced tetrachloroethene (PCE) DNAPL source. It used a controlled‐release test cell with PCE as the primary DNAPL in a porous media groundwater system. Both laboratory tests and a field‐scale pilot test demonstrated that bioaugmentation can stimulate complete dechlorination to a nontoxic end product and that the mass flux from a source zone increases when biological dehalorespiration activity is enhanced through nutrient (electron donor) addition and bioaugmentation. All project goals were met. Important achievements include demonstrating the ability to degrade a PCE DNAPL source to ethene and obtaining significant information on the impacts to the microbial populations and corresponding isotope enrichments during biodegradation of a source area. © 2007 Wiley Periodicals, Inc. 相似文献
49.
Esther del Val Juan Carlos Senar Juan Garrido-Fernández Manuel Jarén Antoni Borràs Josep Cabrera Juan José Negro 《Die Naturwissenschaften》2009,96(7):797-801
Carotenoids may provide numerous health benefits and are also responsible for the integumentary coloration of many bird species.
Despite their importance, many aspects of their metabolism are still poorly known, and even basic issues such as the anatomical
sites of conversion remain controversial. Recent studies suggest that the transformation of carotenoid pigments takes place
directly in the follicles during feather growth, even though the liver has been previously recognised as a storing organ for
these pigments with a certain potential for conversion. In this context, we analysed the carotenoid profile of plasma, liver,
skin and feathers of male Common Crossbills (Loxia curvirostra). Interestingly, the derivative feather pigment 3-hydroxy-echinenone was detected in the liver and in the bloodstream (i.e.
the necessary vehicle to transport metabolites to colourful peripheral tissues). Our results demonstrate for the first time
with empirical data that the liver may act as the main site for the synthesis of integumentary carotenoids. This finding contradicts
previous assumptions and raises the question of possible inter-specific differences in the site of carotenoid conversion in
birds. 相似文献
50.
Francesca Bardi Pien Bosschieter Joke Verheij Attie Go Monique Haak Mireille Bekker Esther Sikkel Audrey Coumans Eva Pajkrt Caterina Bilardo 《黑龙江环境通报》2020,40(2):197-205