Progress 01/01/05 to 09/30/08
Outputs
OUTPUTS: The size of the male sex-producing androgenic hormone (AH) in the freshwater prawn was partially characterized as a "small" protein molecule with less than 30 Kd in molecular weight. This work was down using the bioassay techniques of injecting sexually immature genetic female prawns with extracts of male androgenic gland hormone that had been processed through molecular filters into fractions. The work was presented by student Sam Hwang at the annual CTAHR Research Symposium in April 2008 and won a divisional prize. In addition male prawn androgenic glands have been subjected to the MALDI (Matrix Assisted Laser Desorption/Ionization)analysis to identify mine)for peptides in the gland. This wok was done in cooperation with Dr. Andy Christie of the Bar Harbor Marine Laboratory and colleagues at the University of Wisconsin who performed the analysis. Over a dozen putative AH peptides were identified and sequenced. PARTICIPANTS: Spencer R. Malecha, Principal Investigator DR. Andy Christie, cooperating investigator Center for Marine Functional Genomics Mount Desert Island Biological Laboratory P.O. Box 35 Old Bar Harbor Road Salisbury Cove, Maine 04672 USA DR. Mingming Ma School of Pharmacy University of Wisconsin 777 Highland Avenue Madison, Wisconsin 53705-2222 USA Samuel Hwang, CTAHR undergraduate student Dr. Yong Soo Kim, CTAHR Dept HNFAS, University of Hawaii TARGET AUDIENCES: Targets are the prawn and shrimp aquaculture industry who will used all-female stock produced by sex-reversing parental broodstock with recombinant androgenic hormone made with the knowledge generated by this project. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
This work has led to the design of more precise bioassay systems for prawn the androgenic hormone which are presently being tested. The MALDI analysis showed promising peptides that will be further analyzed from, not whole androgenic gland, but releasates of living androgenic glands dissected in ex-plant culture.
Publications
- No publications reported this period
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Progress 10/01/06 to 09/30/07
Outputs
Work was initiated with Dr. Yong Soo Kim (Department of HNFAS/CTAHR) and an undergraduate research student to partially characterize the prawn androgenic hormone (AH) using a current bioassay. Also work was imitated to develop a new bioassay for the AH since the current one is too slow. Small recently hatched prawn juveniles have been obtained from a commercial supplier, are growing in the lab and are being sexed for use in the bioassay. Prawn androgenic glands (AG) which makes the androgenic hormone have been dissected from large males purchased form a commercial supplier and AH cell-free extracts (AHCFE) from them have been obtained. Preliminary analysis of the AHCFE by PAGE revealed distinct bands that are putative AH. Partial separation analysis separated the AHSFE into >30Kd and <30Kd fractions for bioassay. Mature, but non-ovigerous, females have been obtained and are being husbanded in the laboratory to induce ovary development. Ovary explants will then be
subjected to AHCFE to reduce their activity, which will be assessed using CellTiter 96 One solution Cell proliferation Assay kits from Promega. If this reveals decreased activity, judged by reduced stain production from the kit reagents, it will be a positive bioassay indication of the presence of the androgenic hormone. This test takes hours compared to the six weeks that the current bioassay takes.
Impacts
If we identify an androgenic hormone (AH) we can characterize and clone its gene to make recombinant rAH which can then be used to sex-reverse prawns and shrimp to create all-females in female superior species. The impact of this could be considerable since the shrimp and prawn aquaculture industry, most of which is composed of female-superior species, is worth over $5 Billion annually.
Publications
- No publications reported this period
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Progress 10/01/05 to 09/30/06
Outputs
Work for this period consisted of writing grants to obtain extramural funding to sequence the prawn androgentic hormone and visiting Auburn University to set up an experiment this summer at Auburn to demonstrate the feasibility of using all-female prawns in intensive culture. The Auburn study showed that all-female prawnsre superior at high densitiies. This is necessary to justify funds to sequence the prawn hormone to sex-reverse prawn broodstock to neomales so they can be mated with normal females to produce all-female which are superior to males.
Impacts
Significant yield increases of up to 20 % using all-females are possible
Publications
- No publications reported this period
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Progress 10/01/04 to 09/30/05
Outputs
Work for this period consisted of writing grants to obtain extramural funding to sequence the prawn androgentic hormone and visiting Auburn University. The latter was done with my own funds to set up an experiment this summer at Auburn to demonstrate the feasibility of using all-female prawns in intensive culture. This is necessary to justify funds to sequence the prawn hormone to sex-reverse prawn broodstock to neomales so they can be mated with normal females to produce all-female which are superior to males.
Impacts
All-female culture technology could impact the 5 billion dollar per year shrimp and prawn industry with a 20 to 30 percent increase in production.
Publications
- No publications reported this period
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