Frog Culture
Mostrando 13-24 de 36 artigos, teses e dissertações.
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13. Different chromatin structures along the spacers flanking active and inactive Xenopus rRNA genes.
The accessibility of DNA in chromatin to psoralen was assayed to compare the chromatin structure of the rRNA coding and spacer regions of the two related frog species Xenopus laevis and Xenopus borealis. Isolated nuclei from tissue culture cells were photoreacted with psoralen, and the extent of cross-linking in the different rDNA regions was analyzed by usi
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14. Isolation of Chlamydia psittaci from naturally infected African clawed frogs (Xenopus laevis).
An inclusion-forming agent was isolated from the livers of commercially raised African clawed frogs (Xenopus laevis) involved in an epizootic of high morbidity and mortality. Original isolation was made in McCoy cells. This agent was identified as Chlamydia psittaci based on the formation of typical intracytoplasmic inclusions which developed within 48 h, we
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15. Characterization of metachronal wave of beating cilia on frog's palate epithelium in tissue culture.
1. A method is suggested to measure phase versus distance between beating cilia by means of a photoelectric device. A statistical method interpreting the results thus obtained is discussed. 2. It was found that: (a) an average phase exists between beating cilia, (b) despite strong fluctuations in phase on a short time scale, the average phase was kept consta
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16. ATP regulates muscarine-sensitive potassium current in dissociated bull-frog primary afferent neurones.
1. Bull-frog dorsal root ganglion cells in primary culture were voltage clamped in the whole-cell configuration. The pipette solution contained ATP (5 mM). 2. Step depolarizations (5-70 mV, 0.1-1 s) from a holding potential close to the resting potential (range, -64 to -79 mV) evoked a non-inactivating potassium current with properties indistinguishable from
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17. Muscarinic modulation of calcium current in neurones from the interatrial septum of bull-frog heart.
1. The effects of activation of muscarinic receptors on the voltage-dependent calcium current, ICa, in parasympathetic neurones were examined. 2. Neurones were enzymatically isolated from the interatrial septum of bull-frog (Rana catesbeiana) heart, and were maintained in short-term (1-6 day) tissue culture. ICa was recorded from the cells using whole-cell p
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18. Patterns of frog virus 3 DNA methylation and DNA methyltransferase activity in nuclei of infected cells.
The iridovirus frog virus 3 (FV3) can replicate in culture in fat head minnow (FHM) fish cells or in BHK-21 hamster cells. Viral DNA replication commences about 3 h after infection of FHM cells with FV3. Between 3 and 6 h postinfection (p.i.), a portion of the intranuclear FV3 DNA is partly unmethylated. At later times, p.i., all of the viral DNA in the nucl
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19. Dual Roles of Cripto as a Ligand and Coreceptor in the Nodal Signaling Pathway
The EGF-CFC gene Cripto encodes an extracellular protein that has been implicated in the signaling pathway for the transforming growth factor beta (TGFβ) ligand Nodal. Although recent findings in frog and fish embryos have suggested that EGF-CFC proteins function as coreceptors for Nodal, studies in cell culture have implicated Cripto as a growth factor-lik
American Society for Microbiology.
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20. Myoblasts and myoblast-conditioned medium attract the earliest spinal neurites from frog embryos.
A study was made of the capacity of newly segmented somites, unsegmented mesoderm and medium conditioned by each of these tissues to attract the growth of the earliest spinal neurites from the neural tube of Xenopus laevis in tissue culture. When presented with segmented somitic myoblasts or sheets of skin, spinal neurites grew selectively towards the somiti
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21. Quantal and non-quantal ACh release at developing Xenopus neuromuscular junctions in culture.
1. Single acetylcholine receptor (AChR) channel openings, detected by the whole-cell patch clamp technique, were used to monitor quantal and non-quantal ACh release at synapses in 1- and 2-day-old co-cultures of Xenopus embryonic motoneurons and muscle cells. motoneuron growth cones in ways that presumably reflect muscle-nerve inductive influences and the de
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22. Different spatial patterns of [Ca2+] increase caused by N- and L-type Ca2+ channel activation in frog olfactory bulb neurones.
1. The intracellular calcium concentration ([Ca2+]i) in cultured olfactory bulb neurones of Xenopus laevis tadpoles was imaged using the calcium indicator dyes fluo-3 and Fura Red as well as a laser scanning microscope. 2. Upon extracellular application of brief pulses of a solution with high potassium concentration (high [K+]o), an increase in [Ca2+]i occur
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23. Cyclic AMP regulates an inward rectifying sodium-potassium current in dissociated bull-frog sympathetic neurones.
1. Bull-frog sympathetic neurones in primary culture were voltage clamped in the whole-cell configuration. The pipette solution contained ATP (5 mM). 2. A hyperpolarization-activated sodium-potassium current (H-current: IH) was separated from other membrane currents in a nominally calcium-free solution containing cobalt (2 mM), magnesium (4 mM), barium (2 mM
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24. E2F and its developmental regulation in Xenopus laevis.
The transcription factor E2F has been implicated in cell cycle control by virtue of its association with cyclins, cyclin-dependent kinases, and pRb-related tumor suppressor gene products. Eggs and embryos from the frog Xenopus laevis have been used to investigate the characteristics of E2F-like molecules in the Xenopus cell cycle and throughout early develop