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991.
992.
993.
Ali Tekitek Josette Berreur-Bonnenfant Margarita Rojas Jean-Pierre Ferezou Michel Barbier Edgar Lederer 《FEBS letters》1977,80(2)
Subcultures of ovaries and testis of the crab Carcinus maenas have been performed in the presence of L-[Me-14C]methionine. Introduction in the medium of a chromatographically-purified liposoluble fraction from the androgenic glands of the same animal inhibits the biological methylation of the tRNA of the ovaries by 62%. The inhibition of methylation of five individual bases varies from 45% to 84%. No inhibition of tRNA methylation is observed under the same conditions with testis subcultures. 相似文献
994.
David D. O'Keefe Eduardo Gonzalez-Nio Micheal Burnett Layne Dylla Stacey M. Lambeth Elizabeth Licon Cassandra Amesoli Bruce A. Edgar Jennifer Curtiss 《Developmental biology》2009,333(1):143-160
The small GTPase Rap1 affects cell adhesion and cell motility in numerous developmental contexts. Loss of Rap1 in the Drosophila wing epithelium disrupts adherens junction localization, causing mutant cells to disperse, and dramatically alters epithelial cell shape. While the adhesive consequences of Rap1 inactivation have been well described in this system, the effects on cell signaling, cell fate specification, and tissue differentiation are not known. Here we demonstrate that Egfr-dependent cell types are lost from Rap1 mutant tissue as an indirect consequence of DE-cadherin mislocalization. Cells lacking Rap1 in the developing wing and eye are capable of responding to an Egfr signal, indicating that Rap1 is not required for Egfr/Ras/MAPK signal transduction. Instead, Rap1 regulates adhesive contacts necessary for maintenance of Egfr signaling between cells, and differentiation of wing veins and photoreceptors. Rap1 is also necessary for planar cell polarity in these tissues. Wing hair alignment and ommatidial rotation, functional readouts of planar cell polarity in the wing and eye respectively, are both affected in Rap1 mutant tissue. Finally, we show that Rap1 acts through the effector Canoe to regulate these developmental processes. 相似文献
995.
“The battered child” has recently attracted the attention of physicians and social workers, but despite the fact that inflicted trauma produces characteristic x-ray changes, physicians are often reluctant to admit this cause. The neglected child may be more difficult to diagnose and is probably more common. The most typical example is the infant who is admitted to the hospital for “failure to thrive,” yet gains weight rapidly while away from his parents.The parents of both types of children are likely to be immature and inadequate, but much more study is required before the factors common to these parents are known, to say nothing of the means required for prevention and treatment.When the physician suspects that the parent is causing the difficulties manifested by the child, he should seek the help of a social worker in clarifying the situation and in contacting the appropriate social or legal agency. A greater awareness of the problems of these children should result in more rapid recognition of the condition, the establishment of well-defined methods of handling such cases, and ultimately better legislation to safeguard the child''s rights to a safe and healthy childhood. 相似文献
996.
997.
Marina Loyola Dantas Juliana Menezes Gomes Cabral de Oliveira Lucas Carvalho Sara Timóteo Passos Adriano Queiroz Luiz Henrique Guimar?es Paulo Machado Edgar Carvalho Sérgio Arruda 《Memórias do Instituto Oswaldo Cruz》2014,109(2):202-209
Cutaneous leishmaniasis (CL) is the most frequent clinical form of tegumentary
leishmaniasis and is characterised by a single or a few ulcerated skin lesions that
may disseminate into multiple ulcers and papules, which characterise disseminated
leishmaniasis (DL). In this study, cells were quantified using immunohistochemistry
and haematoxylin and eosin staining (CD4+, CD68+, CD20+, plasma cells and
neutrophils) and histopathology was used to determine the level of inflammation in
biopsies from patients with early CL, late CL and DL (ulcers and papules). The
histopathology showed differences in the epidermis between the papules and ulcers
from DL. An analysis of the cells present in the tissues showed similarities between
the ulcers from localised CL (LCL) and DL. The papules had fewer CD4+ T cells than
the DL ulcers. Although both CD4+ cells and macrophages contribute to inflammation in
early CL, macrophages are the primary cell type associated with inflammation
intensity in late ulcers. The higher frequency of CD20+ cells and plasma cells in
lesions demonstrates the importance of B cells in the pathogenesis of leishmaniasis.
The number of neutrophils was the same in all of the analysed groups. A comparison
between the ulcers from LCL and DL and the early ulcers and papules shows that few
differences between these two clinical forms can be distinguished by observing only
the tissue. 相似文献
998.
A. M. Weigand M. Plath The Volkswagen Foundation Lake Malawi Field School Consortium 《Hydrobiologia》2014,739(1):145-153
Freshwater crabs play an important role for the diversification of shell morphologies in freshwater gastropods. For example, the radiation of the freshwater crab genus Platythelphusa in Lake Tanganyika is thought to have driven shell diversification of the lake’s snail fauna, promoting the evolution of thalassoid shells. No comparable thalassoid snails are known from Lake Malawi. Accordingly, it was hypothesized that the lake’s only freshwater crab, Potamonautes lirrangensis, is not a snail predator. We tested this hypothesis using feeding experiments with specimens caught in the southern part of Lake Malawi. Individual crabs were held in experimental containers offshore and were presented with various food items overnight, after which ingestion frequency was recorded. Potamonautes lirrangensis can be characterized as a scavenger that is opportunistically carnivorous. A preference for fish and snail flesh could be observed, indicating a bias toward carnivory. We observed occasional cracking of the shell in different snail species, with frequent ingestion of artificially crushed specimens, suggesting that crabs do attempt to feed on snails. However, the investigated Lake Malawi gastropods appear to be partly protected against crab predation through thick-walled and low-spired shells (especially Lanistes and Bellamya), obviating the evolution of thalassoid shells carrying rims, ridges, or spines. 相似文献
999.
Thomas Nothnagel Holger Budahn Ilona Krämer Edgar Schliephake Lutz Schreyer Reiner Krämer 《Journal of Phytopathology》2014,162(3):180-189
Five asparagus cultivars, three breeding lines and the wild relative Asparagus amarus were tested for natural infection by Asparagus virus 1 (AV‐1) in experimental fields at two locations over 3 and 4 years, respectively. In the first year after re‐planting the annual crowns in the field, more than 90% of tested plants of cultivars were infected by AV‐1. In the third and fourth year, 100% of tested plants of cultivars were AV‐1 infected. In comparison, all plants of the wild relative A. amarus were completely free of AV‐1, suggesting a high level of resistance. Additionally, 1‐year‐old glasshouse‐cultivated plants of A. officinalis and A. amarus were placed in an AV‐1 provocation cabin under field conditions. Seven months later, 100% of the A. officinalis plants showed a high virus concentration in ELISA, whereas no AV‐1 was detectable in the A. amarus plants. This result was confirmed by highly sensitive AV‐1‐specific RT‐PCR. To exclude vector resistance, the feeding behaviour of green peach aphid Myzus persicae was tested over 12 h using the electrical penetration graph method. Both asparagus genotypes were accepted by the aphids as potential hosts, but the feeding time was significantly longer on A. amarus. A genetic distance analysis of the various cultivars of Asparagus officinalis and selected wild relatives of the JKI collection was carried out, resulting in a clear discrimination of cultivars and wild relatives, especially A. amarus. The potential breeding value of the putative resistance carrier is discussed. 相似文献
1000.
Mariana C.C. Silva Cláudia A.A. de Paula Joana G. Ferreira Edgar J. Paredes-Gamero Angela M.S.F. Vaz Misako U. Sampaio Maria Tereza S. Correia Maria Luiza V. Oliva 《Biochimica et Biophysica Acta (BBA)/General Subjects》2014