X-Message-Number: 7693
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


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 15C for a
period of 15 min, whereas the toxicity neutralization experiments were
conducted at 28C 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.


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