TY - JOUR
T1 - On intersexuality in the crayfish Cherax quadricarinatus
T2 - An inducible sexual plasticity model
AU - Sagi, Amir
AU - Manor, Rivka
AU - Segall, Carmen
AU - Davis, Claytus
AU - Khalaila, Isam
N1 - Funding Information:
The study was supported in part by grants from the DFG (Ke 206/17-1) and the Israeli Ministry of Agriculture (857-0403-00). Recent molecular studies were supported by a grant from the BSF (2001 16).
PY - 2002/1/1
Y1 - 2002/1/1
N2 - Sexual differentiation is a plastic process. The plasticity may be manifested during embryo-genesis, when one set of primordial reproductive ducts develops while the other degenerates. In adults, many normal (e.g., sequential hermaphroditism) and abnormal (e.g., endocrine disorders or exposure to endocrine disruptors such as estrogenic pollutants) cases are known in which sexual plasticity may be expressed as various degrees of feminization. In crustaceans, the androgenic gland (AG) regulates the development of male characteristics; its absence results in feminization, often including the onset of vitellogenesis. A unique model of intersexuality was found in the crayfish Cherax quadricarinatus, in which some degree of natural sexual plasticity is observed. Two to 14% of the population are intersex individuals, having both male and female genital openings. Intersex specimens always function as males but may also contain an ovary in a permanently arrested, pre-vitellogenic state. This sexual plasticity model was recently characterized and investigated with respect to the role of the AG and the onset of vitellogenesis. Removal of the AG in intersex individuals induced the reproductive system to shift from a permanently active male state to a female state. This shift included changes in morphology, cessation of spermatogenesis and onset of secondary vitellogenesis manifested by a change in the ovarian protein profile, translocation of protein kinase C (PKC) in the ovary and appearance of secondary vitellogenic high-density lipoprotein (HDL) in the hemolymph. The vitellogenin gene was found to be induced in the hepatopancreas of AG ablated intersex individuals suggesting that the AG represses transcription of this gene in intact intersex individuals. The experimentally inducible sex shift in the crayfish provides a unique and controlled model system for the study of sexual differentiation and plasticity at the physiological and molecular levels. The findings presented here also illustrate the central role of the AG in the regulation of sexual differentiation in sexually plastic as well as gonochoristic crustacean species.
AB - Sexual differentiation is a plastic process. The plasticity may be manifested during embryo-genesis, when one set of primordial reproductive ducts develops while the other degenerates. In adults, many normal (e.g., sequential hermaphroditism) and abnormal (e.g., endocrine disorders or exposure to endocrine disruptors such as estrogenic pollutants) cases are known in which sexual plasticity may be expressed as various degrees of feminization. In crustaceans, the androgenic gland (AG) regulates the development of male characteristics; its absence results in feminization, often including the onset of vitellogenesis. A unique model of intersexuality was found in the crayfish Cherax quadricarinatus, in which some degree of natural sexual plasticity is observed. Two to 14% of the population are intersex individuals, having both male and female genital openings. Intersex specimens always function as males but may also contain an ovary in a permanently arrested, pre-vitellogenic state. This sexual plasticity model was recently characterized and investigated with respect to the role of the AG and the onset of vitellogenesis. Removal of the AG in intersex individuals induced the reproductive system to shift from a permanently active male state to a female state. This shift included changes in morphology, cessation of spermatogenesis and onset of secondary vitellogenesis manifested by a change in the ovarian protein profile, translocation of protein kinase C (PKC) in the ovary and appearance of secondary vitellogenic high-density lipoprotein (HDL) in the hemolymph. The vitellogenin gene was found to be induced in the hepatopancreas of AG ablated intersex individuals suggesting that the AG represses transcription of this gene in intact intersex individuals. The experimentally inducible sex shift in the crayfish provides a unique and controlled model system for the study of sexual differentiation and plasticity at the physiological and molecular levels. The findings presented here also illustrate the central role of the AG in the regulation of sexual differentiation in sexually plastic as well as gonochoristic crustacean species.
KW - Androgenic gland
KW - Cherax quadricarinatus
KW - Crayfish
KW - Crustacea
KW - Decapoda
KW - Intersexuality
KW - Sexual plasticity
KW - Vitellogenesis
UR - http://www.scopus.com/inward/record.url?scp=0036710246&partnerID=8YFLogxK
U2 - 10.1080/07924259.2002.9652732
DO - 10.1080/07924259.2002.9652732
M3 - Article
AN - SCOPUS:0036710246
SN - 0792-4259
VL - 41
SP - 27
EP - 33
JO - Invertebrate Reproduction and Development
JF - Invertebrate Reproduction and Development
IS - 1-3
ER -