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排序方式: 共有379条查询结果,搜索用时 15 毫秒
41.
42.
Javier Ca?ón Paolo Alexandrino Isabel Bessa Carlos Carleos Yolanda Carretero Susana Dunner Nuno Ferran David Garcia Jordi Jordana Denis Lalo? Albano Pereira Armand Sanchez Katayoun Moazami-Goudarzi 《遗传、选种与进化》2001,33(3):311-332
This study was undertaken to determine the genetic structure, evolutionary relationships, and the genetic diversity among 18 local cattle breeds from Spain, Portugal, and France using 16 microsatellites. Heterozygosities, estimates of Fst, genetic distances, multivariate and diversity analyses, and assignment tests were performed. Heterozygosities ranged from 0.54 in the Pirenaica breed to 0.72 in the Barrosã breed. Seven percent of the total genetic variability can be attributed to differences among breeds (mean Fst = 0.07; P < 0.01). Five different genetic distances were computed and compared with no correlation found to be significantly different from 0 between distances based on the effective size of the population and those which use the size of the alleles. The Weitzman recursive approach and a multivariate analysis were used to measure the contribution of the breeds diversity. The Weitzman approach suggests that the most important breeds to be preserved are those grouped into two clusters: the cluster formed by the Mirandesa and Alistana breeds and that of the Sayaguesa and Tudanca breeds. The hypothetical extinction of one of those clusters represents a 17% loss of diversity. A correspondence analysis not only distinguished four breed groups but also confirmed results of previous studies classifying the important breeds contributing to diversity. In addition, the variation between breeds was sufficiently high so as to allow individuals to be assigned to their breed of origin with a probability of 99% for simulated samples. 相似文献
43.
44.
E. Chiarpotto F. Biasi M. Aragno A. Scavazza O. Danni E. Albano G. Poli 《Cell biochemistry and function》1993,11(1):71-75
The combination of carbon tetrachloride (CCl4) and 1,2-dibromoethane (DBE) in isolated rat hepatocytes led to a significant potentiation of both lipid peroxidation and of plasma membrane damage observed after a single treatment with CCl4. Such a synergistic effect appeared to be related to the CCl4-induced shift of DBE metabolism from the cytosolic conjugation with glutathione towards the microsomal transformation into toxic intermediates. In fact, CCl4 significantly inactivated hepatocyte total GSH-transferase, i.e. the DBE detoxification pathway. Furthermore, while the microsomal metabolism of CCl4 was not affected by the simultaneous presence of DBE, the amount of DBE reactive metabolities covalently bound to hepatocyte protein was significantly enhanced in the presence of CCl4. 相似文献
45.
Marcin Górecki Maria Annunziata M. Capozzi Gianluigi Albano Cosimo Cardellicchio Lorenzo Di Bari Gennaro Pescitelli 《Chirality》2018,30(1):29-42
Three β‐keto sulfoxides ( 1–3 ) were synthesized in enantiopure form and investigated by means of circular dichroism (CD) spectroscopy, both in electronic and vibrational range (ECD, VCD), in combination with quantum chemical calculations. For compound 2 , the X‐ray structure was available; thus, the ECD in the solid state was also considered to reveal the differences between the molecular species in both states. Despite the simplicity of all β‐keto sulfoxides under investigation (29 atoms), reproducing even the major spectral VCD features failed for two compounds, making the use of VCD not ideal to assign their absolute configuration in a reliable way. We demonstrated, however, that the use of ECD spectroscopy, both in solution and solid state, can easily, unambiguously, and without any complication simulate all bands by applying the standard protocol for calculations. This study may stimulate the debate on the need of the use of two chiroptical methods simultaneously in the determination of absolute configurations. 相似文献
46.
An updated checklist of the vascular flora native to Italy 总被引:1,自引:0,他引:1
F. Bartolucci L. Peruzzi G. Galasso A. Albano A. Alessandrini N. M. G. Ardenghi 《Plant biosystems》2018,152(2):179-303
An updated inventory of the native vascular flora of Italy, providing details on the occurrence at regional level, is presented. The checklist includes 8195 taxa (6417 species and 1778 subspecies), distributed in 1092 genera and 152 families; 23 taxa are lycophytes, 108 ferns and fern allies, 30 gymnosperms and 8034 angiosperms. The taxa currently occurring in Italy are 7483, while 568 taxa have not been confirmed in recent times, 99 are doubtfully occurring in the country and 19 are data deficient. Out of the 568 not confirmed taxa, 26 are considered extinct or possibly extinct. 相似文献
47.
Brodfuehrer PD McCormick K Tapyrik L Albano AM Graybeal C 《Invertebrate neuroscience : IN》2008,8(1):31-39
Higher-order projection interneurons that function in more than one behavior have been identified in a number of preparations.
In this study, we document that stimulation of cell Tr1, a previously identified trigger interneuron for swimming in the medicinal
leech, can also elicit the motor program for crawling in isolated nerve cords. We also show that motor choice is independent
of the firing frequency of Tr1 and amount of spiking activity recorded extracellularly at three locations along the ventral
nerve cord prior to Tr1 stimulation. On the other hand, during Tr1 stimulation there is a significant difference in the amount
of activity elicited in the ventral nerve cord that correlates with the motor program activated. On average, Tr1 stimulation
trials that lead to crawling elicit greater amounts of activity than in trials that lead to swimming. 相似文献
48.
Relationships between bacterial diversity and environmental variables in a tropical marine environment, Rio de Janeiro 总被引:6,自引:0,他引:6
Vieira RP Gonzalez AM Cardoso AM Oliveira DN Albano RM Clementino MM Martins OB Paranhos R 《Environmental microbiology》2008,10(1):189-199
This study is the first to apply a comparative analysis of environmental chemistry, microbiological parameters and bacterioplankton 16S rRNA clone libraries from different areas of a 50 km transect along a trophic gradient in the tropical Guanabara Bay ecosystem. Higher bacterial diversity was found in the coastal area, whereas lower richness was observed in the more polluted inner bay water. The significance of differences between clone libraries was examined with libshuff statistics. Paired reciprocal comparisons indicated that each of the libraries differs significantly from the others, and this is in agreement with direct interpretation of the phylogenetic tree. Furthermore, correspondence analyses showed that some taxa are related to specific abiotic, trophic and microbiological parameters in Guanabara Bay estuarine system. 相似文献
49.
Celine Scornavacca Vincent Berry Vincent Lefort Emmanuel JP Douzery Vincent Ranwez 《BMC bioinformatics》2008,9(1):413
Background
Supertree methods combine phylogenies with overlapping sets of taxa into a larger one. Topological conflicts frequently arise among source trees for methodological or biological reasons, such as long branch attraction, lateral gene transfers, gene duplication/loss or deep gene coalescence. When topological conflicts occur among source trees, liberal methods infer supertrees containing the most frequent alternative, while veto methods infer supertrees not contradicting any source tree, i.e. discard all conflicting resolutions. When the source trees host a significant number of topological conflicts or have a small taxon overlap, supertree methods of both kinds can propose poorly resolved, hence uninformative, supertrees. 相似文献50.
Tiago Antao Ana Lopes Ricardo J Lopes Albano Beja-Pereira Gordon Luikart 《BMC bioinformatics》2008,9(1):323