X-Message-Number: 7693 From: Date: Mon, 17 Feb 1997 13:01:07 -0400 (EDT) Subject: Cryo Journal Club 2 Cryo Journal Club 2: Cryoprotectant Toxicity in Penaeid Prawn Embryos S. SAMUEL NEWTON, T. SUBRAMONIAM Cryopreservation of penaeid prawn embryos has definite applications in the aquaculture industry. It can be considered a viable alternative to solve the "seed" scarcity faced during the "lean" season. Presently, there is no protocol for the cryopreservation of prawn embryos. As a study of cryoprotectant toxicity is an essential prerequisite for the development of a cryopreservation protocol, this study focuses on the toxicity of seven well known permeating, low molecular weight cryoprotectants: glycerol, formamide, acetamide, methanol, propylene glycol, dimethyl sulfoxide (Me2SO), and ethylene glycol (EG). In the cryoprotectant toxicity experiments embryos were exposed to cryoprotectant solutions at 15°C for a period of 15 min, whereas the toxicity neutralization experiments were conducted at 28°C with an exposure time of 15 min. The widely used permeating cryoprotectant, glycerol, was toxic to morula stage embryos at concentrations >0.5 M. This study shows that the toxicity tolerance of Penaeus indicus embryos varies with the developmental stage, the later stages being more resistant. Morulae did not tolerate any cryoprotectant above 5 M, whereas the nauplii had survival rates of 45% in 12.5 M methanol and 78% in 6.4 M EG. The toxicity neutralization experiments do not seem to indicate any specific toxicity-blocking mechanism in Me2SO toxicity reduction by EG. Based on the response to cryoprotectant toxicity, nauplius stage larvae of penaeid prawns can be considered a suitable stage for cryopreservation, both by the conventional slow cooling method and also the vitrification technique as it allows use of high levels of cryoprotectant. Cryobiology, v 33, n 1, February 1996, p172-177 (ID CY960017) I think one can conclude from this experiment that neuro suspension is better than whole body suspension because different cell types are not protected effectively by one or more universal cryoprotectant. Your participation will be appreciated. J.C. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=7693