• Genomics & Informatics
• /
• v.3 no.1
• /
• pp.24-29
• /
• 2005

TRPV2 is a non-specific cation channel expressed in sensory neurons, and activated by noxious heat. Particularly, TRPV2 has six transmembrane domains and three ankyrin repeats. TRPV2 has been cloned from various species such as human, rat, and mouse. Oocytes of Xenopus laevis - an African clawed frog ­have been widely used for decades in characterization of various receptors and ion channels. The functional property of rat TRPV2 was also identified by this oocyte expression system. However, no TRPV2 orthologue of Xenopus laevis has been reported so far. Hence, we have focused to clone a TRPV2 orthologue of Xenopus laevis with the aid of bioinformatic tools. Because the genome sequence of Xenopus laevis is not available until now, a genome sequence of Xenopus tropicalis - a close relative species of Xenopus laevis - was used. After a number of bioinformatic searches in silico, a predicted full-length sequence of TRPV2 orthologue of Xenopus tropicalis was found. Based on this predicted sequence, various approaches such as RT-PCR and 5' -RACE technique were applied to clone a full length of Xenopus laevis TRV2. Consequently, a full-length Xenopus laevis TRPV2 was cloned from heart cDNA.

• Korean Journal of Veterinary Research
• /
• v.37 no.1
• /
• pp.9-13
• /
• 1997

The gastrointestinal endocrine cells of the African clawed toad, Xenopus laevis have been investigated immunohistochemically using the avidin-biotin method. Seven antisera were tested and three endocrine cell types immunoreacted with antisera to neurotensin, GRP and substance P. A moderate number of neurotensin-immunoreactive cells were weakly reacted in the small intestine. GRP-immunoreactive cells were mainly situated among the upper portion in the fundic glands, and the basal portion in the pyloric glands. These cells were oval and round in shape. On the other hand, in the intestine they were thin spindly cells with the epithelium. Substance P-immunoreactive cells were observed in among intestinal epithelium. However, no secretin-, motilin-, M-Enk- and PYY-immunoreactive cells were found in the GIT of the African clawed toads.

• Development and Reproduction
• /
• v.27 no.3
• /
• pp.159-165
• /
• 2023

The Ruvb-like AAA ATPase1 (Ruvbl1; also known as Pontin) is an evolutionary conserved protein belonging to the adenosine triphosphates associated with diverse cellular activities (AAA+) superfamily of ATPases. Ruvbl1 is a component of various protein supercomplexes and is involved in a variety of cellular activities, including chromatin remodeling, DNA damage repair, and mitotic spindle assembly however, the developmental significance of this protein is unknown and needs detailed investigation. We investigated the developmental significance of Ruvbl1 in multiciliated cells of the Xenopus laevis epidermis since ruvbl1 is expressed in the multiciliated cells and pronephros during X. laevis embryogenesis. The knockdown of ruvbl1 significantly impaired cilia-driven fluid flow and basal body polarity in the X. laevis epidermis compared to control embryos, but did not affect cilia morphology. Our results suggest that Ruvbl1 plays a significant role in embryonic development by regulating ciliary beating; however, further investigation is needed to determine the mechanisms involved.

• Proceedings of the Zoological Society Korea Conference
• /
• 1995.10b
• /
• pp.241.2-241
• /
• 1995

No Abstract, See Full Text

• The Korean Journal of Zoology
• /
• v.33 no.1
• /
• pp.94-102
• /
• 1990

In Xenopus laevis the cranial myotomes, W, X, Y and Z represent transient embry-specific structures since they undergo reduction" in the later stage of development. An extensive set of expertmental studies was undertaken in order to discriminate whether the cranial myotomes perform a programmed autonomous death or reduction" by the influence from surrounding tissue such as otic vesicle. Removal of the neighboring otic vesicle did not affect WXYZ degeneration. Grafting the otic vesicle to novel site along the somite file did not induce local myotome degenration. When anterior-most somitic primordia were relocated to the trunk somite region, they underwent reduction eventually. Likewise, with the transplantation of posterior somite forming region into the anterior, autonomous differentiation pafferns were observed. And the cullture of presumptive somitic tissue revealed that WXYZ might degnerate like in vivo. It is therefore concluded that the cranial myotomes of Xenopus laevis exhibit an autonomous cell death during later embryogenesis.yogenesis.

• Journal of Environmental Science International
• /
• v.18 no.11
• /
• pp.1247-1259
• /
• 2009

We investigated the toxic effects of carbaryl on early embryo development in the African clawed frog, Xenopus laevis. To test the toxic effects, frog embryo teratogenesis assays using Xenopus were performed. Embryos were exposed to various concentrations of carbaryl ($5{\sim}320\;{\mu}M$). $LC_{100}$ for carbaryl was $320\;{\mu}M$, and the $LC_{50}$ determined by probit analysis was the concentration of $235.68\;{\mu}M$. Exposure to $160\;{\mu}M$ of carbaryl resulted in 10 different types of severe external malformations. Histological examination revealed dysplasia of the eyes, heart, guts, somatic muscle, dorsal, liver, blood vessel and swelling of the pronephric ducts. Malformation of neural tissue and brain was not severe even in the high dose of carbaryl. Benzidine blood stain showed distinct inhibition of inducing erythrocytes in embryos and animal cap explants. Electron micrographs of embryo revealed retinal detachment, loose photoreceptor lamella and the degeneration of sarcomeres in the carbaryl-treated group. The mitochondrial degeneration was also observed in the test group.

• The Korean Journal of Zoology
• /
• v.27 no.2
• /
• pp.93-102
• /
• 1984

Xenopus laevis eggs were de-jellied and manually manipulated to remove their vitelline membranes. They were then positioned in a variety of orientations re. gravity. That is the future ventral side was located upwards (opposed gravity) or downwards (faced gravity). Development through the tailbud stage was observed and the frequency of double axes formation recorded. Orientation of the egg re. its natural polarity was not an important factor in generating double axes. Its physical structure (flattened re. spherical), however, appeared to be important in determining the frequency of twinning. These observations give insights into the mechsnism of polarity establishment in anuran eggs, and provide methods which should be useful for studies on primary embryonic induction.

• Animal cells and systems
• /
• v.1 no.3
• /
• pp.491-496
• /
• 1997

When olfactory placodes are transplanted at stages 23/24 from Xenopus laevis to Xenopus borealis hosts of the same age, it is possible to distinguish the cell populations of the host and donor due to the peculiar nuclear Q bands specific to X. borealis. I have replaced the eye anlage in each of a number of X. borealis with the transplanted olfactory placode of an individual X. laevis, or vice versa. In most instances, the placode of the donor fuses with that of the host. When fusion occurs, but not when the host and donor orqans grow separately, the cells of the donor were replaced gradually and according to a characteristic pattern by cells of the host. The basal cells of the donor were the first to be replaced, followed by the more matured cells of the sensory epithelium. This cellular substitution, proceeding in an orderly fashion from bottom to upper layers of the epithelium, depends on the fusion of the two organs. This observation suggests intercellular contacts in the mitotic zone of the two organs favor the host's cells over those of the donor.

• Journal of Pharmaceutical Investigation
• /
• v.25 no.4
• /
• pp.299-305
• /
• 1995

Cloning the gene encoding a dipeptide transporter is necessary for understanding the absorption mechanism of peptides and peptide-like drugs in the gastrointestinal tract. Functional expression of a dipeptide transporter after microinjection into Xenopus laevis oocytes was performed using the mRNA purified from human intestinal HT-29 cells. Fifty nanoliters of purified mRNA (1 mg/mL) were microinjected into healthy oocytes followed by incubation for 4 days in order to express a dipeptide transporter. Functional expression was determined by a uptake assay using 10 Ci/mL $[^3H]-glycylsarcosine$, a dipeptide substate of the transporter. Seasonal variability and batch-to-batch variability were greater in summer. The usage of beveled micropipettes improves viability of oocytes at 4 days after microinjection. Expression of a dipeptide transporter in oocytes after microinjection of mRNA obtained from HT-29 cells was significantly larger than those after microinjection of water or mRNA obtained from the rabbit intestine.

• Proceedings of the Korean Society of Life Science Conference
• /
• 2008.10a
• /
• pp.59.1-59.1
• /
• 2008