scholarly journals Unusual coelom formation in the direct-type developing sand dollar Peronella japonica

2011 ◽  
Vol 240 (11) ◽  
pp. 2432-2439 ◽  
Author(s):  
Jun Tsuchimoto ◽  
Toshihiro Yamada ◽  
Masaaki Yamaguchi
Keyword(s):  
Sand Dollar ◽  
Coelom Formation

Development of the sand dollar Scaphechinus mirabilis

2008 ◽  
Vol 34 (6) ◽  
pp. 415-420 ◽  
Author(s):  
S. Sh. Dautov ◽  
S. D. Kashenko
Keyword(s):  
Sand Dollar ◽  
Scaphechinus Mirabilis

scholarly journals Effects of 5-Fluorodeoxyuridine and Related Halogenated Pyrimidines on the Sand-Dollar Embryo

1960 ◽  
Vol 7 (1) ◽  
pp. 61-71 ◽  
Author(s):  
David A. Karnofsky ◽  
Ross S. Basch
Keyword(s):  
Embryonic Development ◽  
Random Pattern ◽  
Protective Agent ◽  
Sand Dollar ◽  
Blastula Stage ◽  
Bacterial Dna ◽  
Fluorinated Pyrimidines ◽  
Minimal Lethal Concentration ◽  
Embryonic Death

The embryo of the sand-dollar (Echinarachnius parma) was exposed to various concentrations of fluorinated pyrimidines immediately after fertilization. FUDR (5-fluorodeoxyuridine) was most active, and a concentration of 2 to 4 mγ/10 cc. (0.8 to 1.6 x 10-6 m.eq./liter) blocked development at the early blastula stage. Larger doses interrupted development at the same stage. This effect was prevented by thymidine (TDR) and thymine (T); and these pyrimidines protected against many times the minimal lethal concentration of FUDR. TDR was active as a protective agent if added just before early blastula formation. The other fluorinated pyrimidines, 5-fluorouracil (FU), 5-fluorouridine (FUR), 5-fluorocytidine (FCR), 5-fluorodeoxycytidine (FCDR), and 5-fluoroorotic acid (FO), were also studied. These drugs produced effects on embryonic development similar to those seen with FUDR. The effective concentrations, however, varied greatly. T and TDR provided protection against these drugs, but in most cases they were not so effective as against FUDR. 5-Bromodeoxyurdine (BrUDR), beginning at the early blastula stage, caused a random pattern of embryonic death up to the pluteus stage. This drug has been shown to be incorporated into bacterial DNA. BrUDR protected embryos against the early lethal effects of FUDR presumably acting as a thymidine substitute, but the embryos died subsequently in a pattern similar to that seen with BrUDR alone. FUDR and BrUDR appear to inhibit the formation and alter the structure of DNA, respectively, distinctive effects whch may provide a means for studying the role of DNA in embryonic development.

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