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221.
Plant Molecular Biology Reporter - Cynodon is a genus with a wide distribution in tropical and subtropical areas. Ploidy levels in Cynodon range from diploid to hexaploid; hence, polyploidy is the...  相似文献   
222.
We studied the relationship between the morphology of the reproductive system and the reproductive strategies of six neotropical catfishes using macroscopic and microscopic analyses. The reproductive system of the examined Siluriformes showed diversified characteristics, but permitted their being grouped according to three reproductive strategies: pelagic spawning, demersal spawning, and internally fertilizing. The pelagic spawners Pseudoplatystoma corruscans and Conorhynchos conirostris have testes that are characterized by filiform lobes, absence of testicular secretion, full‐grown oocytes of small diameter, thin zona radiata, and cuboidal follicular cells. Pimelodus maculatus is morphologically distinct from the other two pelagic spawners catfishes due to the presence of testicular secretion. The demersal spawners Lophiosilurus alexandri and Rhinelepis aspera possess homogeneous testicular secretion, large mature oocytes, and columnar follicular cells. The most specialized reproductive system was observed in the internally fertilizing Trachelyopterus galeatus, which possesses a seminal vesicle accessory to the testes, spermatozoa with elongated nuclei that form spermatozeugmata, and a secretory ovarian lamellar epithelium that is associated with sperm storage. The reproductive system observed in Neotropical catfishes showed a relationship associated with the type of fertilization and the reproductive strategies of the six species studied. © 2011 Wiley‐Liss, Inc.  相似文献   
223.
Dream thought is both impoverished and non-logical. While some inferential reasoning is present in dreaming, many illogicalities that would demand cognitive attention during waking go unnoticed during sleep. The physiological basis of this illogicality may include frontal lobe inactivation and amionergic demodulation. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
224.
The authors verified for the first time in the State of S?o Paulo, Brazil, the presence of Cooperia curticei Giles, 1892 (Nematoda: Trichostrongylidae), parasitizing the small intestine of cattle at the Region of Alta Araraquarense.  相似文献   
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226.
Hydrobiologia - Local ecological knowledge (LEK) has been increasingly acknowledged as a potential source of information on natural resources, especially in under sampled areas. In the Amazon, a...  相似文献   
227.
Molecular Biology Reports - Festuca L. has more than 600 perennial species described, which makes it the largest genus within the family Poaceae. In Brazil, only two native species of Festuca have...  相似文献   
228.
Musculoskeletal disorders of the neck are becoming a major concern in industry. Several studies reported the association of neck pain, discomfort, and symptoms with different occupations in industry. Thus, the main objective of this study is to review and evaluate biomechanical techniques used in analyzing the occupational factors leading to neck pain and disorders. Recommendations for future research are also discussed.  相似文献   
229.
Peptides are biomolecules that may have several biological activities which makes them important to the environment in which they operate. Sometimes it is necessary for larger amounts of peptides to carry out some studies, like biological tests, NMR structural research or even interaction studies between peptides with other molecules. Expression can be an alternative for that. However, synthesis is specially useful when unnatural modifications or introduction of site specific tags are required. Synthetic peptides have been used for different studies such as cell signaling, development of epitope-specific antibodies, in cell-biology, biomarkers for diseases etc. Many different methodologies for peptide synthesis can be found in the literature. Solid phase peptide synthesis (SPPS) has been largely used and can be an excellent alternative to achieve larger quantities of these biomolecules. In this mini review, we aim to describe the SPPS and explain some of the mechanistic aspects and reagents involved in all phases of the synthesis: the use of resin, the ninhydrin test, some of the protecting groups, coupling reagents for peptide bond formation and the cleavage process.  相似文献   
230.
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