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Diachronic (1979–2003) analysis of rice genetic diversity in Guinea did not reveal genetic erosion 总被引:1,自引:1,他引:0
Mamdou B. Barry Jean Louis Pham Sedou Béavogui Alain Ghesquière Nour Ahmadi 《Genetic Resources and Crop Evolution》2008,55(5):723-733
Greater insight into the dynamics of genetic resources of crop plants is needed in order to pinpoint detrimental evolutionary
patterns and draw up conservation priorities. Temporal evolution of rice genetic diversity was monitored in Maritime Guinea
where subsistence-oriented agriculture prevails. Diachronic comparison was performed between samples collected in six villages
during the 1979/1982-period and in 2003, based on the names and number of varieties inventoried and the polymorphism of microsatellite
markers. The number of varieties appeared not to be comparable between the two dates, due to differences in the collection
methods. The varietal composition had evolved very substantially between the two collection dates. Many long-duration varieties
present in 1979/1982 had been abandoned and several improved varieties had been introduced. The mean number of alleles per
locus and per accession was significantly higher in accessions collected in 2003. Pairwise comparisons of the mean number
of alleles per locus in 1979/1982–2003 homonymous accession pairs indicated higher intra-accession diversity for the 2003
collections. Genetic differentiation, measured with the F
ST values, was very high and significant for more than 80% of these pairs of accessions. The overall genetic differentiation
between accessions from the two collections dates was also significant. Significant changes were also observed for allelic
composition. However, alleles specific of each collection date had much lower frequency, compared to alleles common to the
two collection dates. These results suggest that rice genetic diversity in Maritime Guinea has been maintained or even enhanced.
Old collections of crop genetic resources are often not exhaustive enough to undertake perfect diachronic comparison. New
methods to utilize this historical data for diversity monitoring are needed. 相似文献
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The ubiquity of the Internet has made disseminating information across geographical boundaries a relatively easy task. Apart from text-based materials, the Internet provides an easy means to transmit images, sound, video, and other multimedia content to a global audience, making it an ideal medium for establishing distance learning programs. Two Internet-based distance learning courses were developed to teach animal physiology to veterinary technicians in the School of Veterinary Medicine at Purdue University. These distance learning course sites are designed to take advantage of multimedia technology to enhance students' learning experiences. Multimedia has been used in education to make the learning process more engaging and interactive. The two course sites have a number of multimedia features that complement the textual subject matter. This article describes the features of the course Web sites and summarizes our experiences in designing and conducting Web-based physiology courses to distance learners. In addition, we describe the characteristics of our distance learning students. 相似文献
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In recent years, the Internet has become an effective and accessible delivery mechanism for distance education. In 2003, 81% of all institutions of higher education offered at least one fully online or hybrid course. By 2005, the proportion of institutions that listed online education as important to their long-term goals had increased by 8%. This growth in available online courses and their increased convenience and flexibility have stimulated dramatic increases in enrollment in online programs, including the Veterinary Technology Distance Learning Program (VT-DLP) at Purdue University. Regardless of the obvious benefits, distance learning (DL) can be frustrating for the learners if course developers are unable to merge their knowledge about the learners, the process of instructional design, and the appropriate uses of technology and interactivity options into effective course designs. This article describes strategies that we have used to increase students' learning of physiology content in an online environment. While some of these are similar, if not identical, to strategies that might be used in a face-to-face (f2f) environment (e.g., case studies, videos, concept maps), additional strategies (e.g., animations, virtual microscopy) are needed to replace or supplement what might normally occur in a f2f course. We describe how we have addressed students' need for instructional interaction, specifically in the context of two foundational physiology courses that occur early in the VT-DLP. Although the teaching and learning strategies we have used have led to increasingly high levels of interaction, there is an ongoing need to evaluate these strategies to determine their impact on students' learning of physiology content, their development of problem-solving skills, and their retention of information. 相似文献
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Naima Khatib Zagh Nour El Islam Bachari 《Journal Of Aquatic Food Product Technology》2019,28(6):667-676
The study of the discharge of metallic pollutants into the marine environment through biological material such as sardines makes it possible to evaluate the quality of the biological resources and of the marine environment. The sardine (Sardina pilchardus) is the most popular species for fishing and the most consumed species by the Algiers population. Two toxic metals that can affect human health are studied in this fish. A year of sampling with fishermen was conducted. Sampling was done in the spring, in the autumn, and in April between April 2014 and April 2015. Sampled sardines were grouped by size classes. The gills and muscle were recovered by size classes. The results were explored using a principal components analysis and compared by a Mann-Whitney distribution test. An atomic absorption spectrophotometer was used in the laboratory for analysis. The most important results show that lead levels were higher than those of cadmium in the gills and muscle. For sardines, lead contamination appears to have both gill and food origins. Mann-Whitney comparison tests confirmed this homogeneous distribution of lead between the gills and muscle. The correlation between cadmium in the gills and height or weight is more substantial than that with muscle. The origin of cadmium in sardines is branchial. The food origin appears secondary. From our point of view, the effect of season, i.e., winter (December) and spring (April), favors an increase in metal levels in parallel to the production reserves planned for spawning. The effect of season was observed by use of a biplot. A significant reduction in cadmium and lead content was observed in September. The high temperature, an environmental factor, induced stress that reduced the metal concentrations and the decontamination induced by the issuance of genital products in early summer. 相似文献
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Aissaoui Fatima Hedjal-Chebheb Mariam Soltani Abir Haouel-Hamdi Soumaya Talhi Oualid Ziani Borhane Eddine Chérif Mediouni-Ben Jemâa Jouda 《植物病害和植物保护杂志》2021,128(5):1167-1176
Journal of Plant Diseases and Protection - The aims of this work were to point out the seasonal variation in chemical composition and evaluate the insecticidal activities of Mentha spicata and... 相似文献
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El-Elimat Tamam Qasem Wala’a M. Al-Sawalha Nour A. AbuAlSamen Mahmoud M. Munaiem Ramzi T. Al‐Qiam Reema Al Sharie Ahmed H. 《Plant foods for human nutrition (Dordrecht, Netherlands)》2022,77(3):447-454
Plant Foods for Human Nutrition - Matcha tea has been used as an adjunct in weight loss programs. The weight loss effects of matcha tea were evaluated in a prospective non-randomized open-label... 相似文献
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Rutherfurd SM Torbatinejad NM Moughan PJ 《Journal of agricultural and food chemistry》2006,54(25):9453-9457
True ileal total lysine digestibility was determined and compared with true ileal reactive lysine digestibility when applied to 20 cereal-based breakfast foods. Semisynthetic diets each containing a breakfast cereal as the sole protein source were formulated and fed to growing rats. Titanium dioxide was included as an indigestible marker. Digesta were collected from the rats and total (conventional amino acid analysis) and reactive (guanidination) lysine were determined in both diets and digesta. The true ileal reactive lysine digestibility ranged from 53 to 108% and was significantly higher than the true ileal total lysine digestibility for most of the breakfast cereals. Available lysine content (digestible reactive lysine content) ranged from 0.21 to 3.5 g/kg across the breakfast cereals. The conventional measure of digestible total lysine content significantly overestimated (on average 37%) available lysine for the majority of the cereals. Breakfast cereals undergo a significant degree of lysine modification probably as a result of processing during manufacture. 相似文献
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Manhattan Lebrun Florie Miard Nour Hattab-Hambli Sylvain Bourgerie Domenico Morabito 《Water, air, and soil pollution》2018,229(5):163
With the development of the industrial era, environmental pollution by organic and inorganic pollutants increased and became a worldwide issue. Particularly, former industrial sites often present high concentrations of metal(loid)s. These pollutions have adverse effects not only on the environment but also to human health, as pollutants can enter the food chain. Therefore, contaminated sites need rehabilitation. Phytoremediation is a clean and low-cost solution to remediate such sites. However, vegetation establishment can be difficult on such extreme soils from both a physical and a chemical point of view. Consequently, amendments, like biochar and garden soil, must be applied. Biochar, product of biomass pyrolysis under low-oxygen conditions, showed beneficial effects on soil fertility and plant growth, as well as metal(loid) sorption properties. The aims of this study were to investigate the effects of two organic amendments, biochar and garden soil, alone or combined, on the physico-chemical properties of a post-industrial soil and the growth of two Salix species (Salix alba and Salix viminalis) and evaluate the phytostabilizing capacities of the two Salix species. In this goal, a greenhouse experiment was performed, using garden soil at 50% (v/v) and/or biochar at 2 or 5% (w/w). The results showed that biochar did not improve soil physico-chemical properties, neither did it affect plant parameters (dry weight, organ metal(loid)s concentrations). Moreover, higher metal(loid) concentrations were found in the roots compared to the upper parts. Finally, S. alba presented lower metal(loid) concentrations in the aboveground parts compared to S. viminalis, associated with a good growth, which make it a better candidate for phytostabilization of the studied soil. 相似文献