(1998) Characterization of the monocarboxylate transporter 1 expressed in. MPF is neither progesterone nor a metabolite of progesterone. 678 J Cell Biol 108:852-892 Kline D (1988) Calcium-dependent events at fertilization of the Bement WM, Capco DG (1990 a) Transformation of the amphibian frog egg: Injection of a calcium buffer blocks ion channel open- oocyte into the egg: structural and biochemical events. carsten.wagner@uni-tuebingen.de Xenopus are kept at 17–19°C, on a 12 hr off/12 hr on dark/light cycle. Oogenesis in the anuran Xenopus laevis can be divided into six stages based on the anatomy of the developing oocyte. Zampighi, G. A., Kreman, M., Boorer, K. et al. On the other hand, OsYSL18 can transport Fe(III)–DMA but not Fe(II)–NA, Zn(II)–DMA or Zn(II)–NA (Aoyama et al., 2009). Such primed females can be used four or more months after ovulation. The ovarian lobes are pulled apart by blunt dissection with fine forceps and small clumps of oocytes are isolated. Alternatively, activity can be monitored using the Boc-Phe-Ser-Arg↓NHMec artificial substrate in a 25 mM Tris HCl buffer pH 8.0 containing 200  mM NaCl [5]. These findings were something of a surprise, given that the relatively low opacity of Xenopus eggs and embryos was assumed to make them poor subjects for live-cell imaging. Xenopus is a genus of African frogs that are commonly known as the African clawed frogs. (1984) Expression of functional acetylcholine receptor from cloned cDNAs. Microinjection of Xenopus laevis oocytes is an excellent system for studying nuclear transport because of the large size of the oocyte and its high nuclear pore complex (NPC) density. Each region was analyzed to determine the amount of total cellular RNA, poly(A)+RNA, and newly synthesized ribosomal RNA. Researchers have found that the genetic ZZ/ZW sex determination system in this genus (females are heterozygous for dominant female-determining factors and for recessive male-determining factors, although no morphologically distinct sex chromosomes have been found) is disrupted by polyploidy (reviewed in Kobel and Du Pasquier, 1986). P.Hanke, R.Grygorczyk, A.Tintschl, H.Fasold1 and H.Passow 1. The same strategy was applied by different investigators to successfully clone rabbit PEPT1 and rabbit PEPT2 from the rabbit intestinal and renal cDNA libraries, respectively (29,30). J Am Assoc Lab Anim Sci … Please Specify Uncurling arrive around 38 NF