perform (a play), especially on a stage; "we are going to stage `Othello" (同)present, represent
a section or portion of a journey or course; "then we embarked on the second stage of our Caribbean cruise" (同)leg
a small platform on a microscope where the specimen is mounted for examination (同)microscope stage
a large platform on which people can stand and can be seen by an audience; "he clambered up onto the stage and got the actors to help him into the box"
any scene regarded as a setting for exhibiting or doing something; "All the worlds a stage"--Shakespeare; "it set the stage for peaceful negotiations"
the theater as a profession (usually `the stage'
plan, organize, and carry out (an event); "the neighboring tribe staged an invasion" (同)arrange
attend a dance or a party without a female companion
adult male deer
getting rid of a stage of a multistage rocket
travel by stagecoach
(genetics) the diploid cell resulting from the union of a haploid spermatozoon and ovum (including the organism that develops from that cell) (同)fertilized_ovum
written for or performed on the stage; "a staged version of the novel"
BRCA2 is a mediator of RAD51- and DMC1-facilitated homologous recombination in Arabidopsis thaliana.
Seeliger K, Dukowic-Schulze S, Wurz-Wildersinn R, Pacher M, Puchta H.SourceBotanical Institute II, Karlsruhe Institute of Technology (KIT), Kaiserstraße 12, D-76131 Karlsruhe, Germany.
The New phytologist.New Phytol.2012 Jan;193(2):364-75. doi: 10.1111/j.1469-8137.2011.03947.x. Epub 2011 Nov 11.
• Mutations in the breast cancer susceptibility gene 2 (BRCA2) are correlated with hereditary breast cancer in humans. Studies have revealed that mammalian BRCA2 plays crucial roles in DNA repair. Therefore, we wished to define the role of the BRCA2 homologs in Arabidopsis in detail. • As Arabid
Disrupted Oogenesis in the Frog Xenopus tropicalis After Exposure to Environmental Progestin Concentrations.
Säfholm M, Norder A, Fick J, Berg C.AbstractLevonorgestrel is a synthetic progesterone commonly used in pharmaceuticals, e.g. in contraceptives. It is found in sewage treatment plant effluents at concentrations up to 30 ng/L, and was recently shown to pose a threat to egg laying in fish. Information on the susceptibility of adult frogs to progestin toxicity is lacking. The present study aimed to 1) characterize progestagenic effects on the full cycle of oogenesis (egg development) in frogs, and 2) determine female amphibians' susceptibility to reproductive impacts from progestagenic compounds in the environment. Sexually mature female Xenopus tropicalis were exposed to levonorgestrel via the surrounding water for 7 days (0, 51, or 307 ng/L) or 28 days (0, 1.3, 18, 160, or 1240 ng/L). Their ovaries were analyzed histologically with respect to frequencies of immature (in early meiotic prophase I), previtellogenic, vitellogenic, mature, and atretic oocytes. The 28-day exposure caused reduced proportions of oocytes at immature, vitellogenic and mature stages and increased proportions of previtellogenic oocytes, compared with the control. The lowest tested concentration, 1.3 ng/L, increased the proportions of previtellogenic oocytes and reduced the proportions of vitellogenic oocytes, indicating inhibited vitellogenesis. The present study shows that progestin concentrations found in the aquatic environment impaired oogenesis in adult frogs. Our results indicate that progestagenic effects on oocyte development include interrupted germ cell progression into meiosis and inhibited vitellogenesis. Considering the crucial role of oogenesis in female fertility our results indicate that progestagenic pollutants may pose a threat to reproduction in wild amphibian populations.
Biology of reproduction.Biol Reprod.2011 Dec 21. [Epub ahead of print]
Levonorgestrel is a synthetic progesterone commonly used in pharmaceuticals, e.g. in contraceptives. It is found in sewage treatment plant effluents at concentrations up to 30 ng/L, and was recently shown to pose a threat to egg laying in fish. Information on the susceptibility of adult frogs to pro
Journal of Reproduction and Development advpub(0), 2015
… FISH analysis revealed the sex chromosomal position during spermatogenesis in each stage of seminiferous epithelia and in each spermatogenic cell. … In the zygotene and pachytene spermatocytes at prophase I, X and Y chromosomes had a random distribution. …
… Histological and air-dried specimens revealed degeneration of zygotene or early pachytene spermatocytes and very few numbers of pachytene and diplotene spermatocytes, round and elongate spermatids and mature spermatozoa in the mutant testis. … Therefore, it was concluded that spermatogenesis is disrupted at the zygotene to early pachytene stages of meiosis in the mutant males. …
The site of chromosomal DNA synthesis during zygotene stage of meiosis was explored by electron microscope autoradiography. Zygonema of <I>Lilium longiflorum</I> cultured in the presence of <SUP>3</SUP>H-thymidine for 24 h ...
Zygotene Stage (n.) 1. (MeSH) Premier stade de la première division de la MEIOSE (durant lequel la SEÉGRÉGATION DES CHROMOSOMES se produit). Elle se divise en cinq stades : leptotène, zygotène, pachytène, diplotène et ...