Effects of various ammonium salts, amines, polyamines and α-methylornithine on rRNA synthesis in neurula cells of Xenopus laevis and Xenopus borealis

1986 ◽  
Vol 18 (2) ◽  
pp. 101-108 ◽  
Author(s):  
Koichiro Shiokawa ◽  
Yuichi Kawazoe ◽  
Kosuke Tashiro ◽  
K. Yamana
Keyword(s):  
Xenopus Laevis ◽  
Ammonium Salts ◽  
Rrna Synthesis ◽  
Xenopus Borealis

Mode of action of ammonia and amine on rRNA synthesis in Xenopus laevis embryonic cells

Development ◽  
1987 ◽  
Vol 100 (3) ◽  
pp. 513-523
Author(s):  
K. Shiokawa ◽  
Y.C. Fu ◽  
Y. Kawazoe ◽  
K. Yamana
Keyword(s):  
Xenopus Laevis ◽  
Ammonium Salt ◽  
Culture Medium ◽  
Surrounding Medium ◽  
Ammonium Salts ◽  
Rrna Synthesis ◽  
Transcriptional Level ◽  
Embryonic Cells ◽  
Inhibitory Effects ◽  
Atp Level

Recently, we found that rRNA synthesis in dissociated embryonic cells of Xenopus laevis is selectively inhibited by ammonium salts added to their surrounding medium. Similar effects were also observed in cells treated with amines. In this report, we analysed in more detail the effects of an ammonium salt and trimethylamine on rRNA synthesis in Xenopus embryonic cells cultured under several different conditions. Results obtained showed that ammonia and trimethylamine inhibit formation of 40S pre-rRNA, without inducing breakdown (wastage) or aberrant processing of the 40S pre-rRNA. Such inhibitory effects were also shown not to be due to interference with cellular ATP level. Furthermore, we found that the effects of both ammonium salt and trimethylamine were completely abolished when Na+ in the culture medium of the testing cells was replaced by choline ions. These results favour the view that the inhibition of rRNA synthesis by ammonia and amine is realized at the transcriptional level or at the step before the formation of 40S pre-rRNA, most probably via a slight increase of intracellular pH, but not via an inhibition in energy-generating systems.

A comparison of host-defense peptides in skin secretions of female Xenopus laevis×Xenopus borealis and X. borealis×X. laevis F1 hybrids

Peptides ◽  
2013 ◽  
Vol 45 ◽  
pp. 1-8 ◽  
Author(s):  
Milena Mechkarska ◽  
Manju Prajeep ◽  
Jérôme Leprince ◽  
Hubert Vaudry ◽  
Mohammed A. Meetani ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Host Defense ◽  
F1 Hybrids ◽  
Host Defense Peptides ◽  
Skin Secretions ◽  
Defense Peptides ◽  
Xenopus Borealis

Ammonium lon as a possible regulator of the commencement of rRNA synthesis in Xenopus laevis embryogenesis

1986 ◽  
Vol 115 (2) ◽  
pp. 380-391 ◽  
Author(s):  
Koichiro Shiokawa ◽  
Yuichi Kawazoe ◽  
Hajime Nomura ◽  
Takayo Miura ◽  
Norihiko Nakakura ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Rrna Synthesis
Sign in / Sign up

Export Citation Format

Share Document