The histological and ultra-structure of the pituitary in diploid red crucian carp(Carassius auratus red var.),triploid crucian carp and allotetraploid hybrids within and after the breeding season were comparatively st...The histological and ultra-structure of the pituitary in diploid red crucian carp(Carassius auratus red var.),triploid crucian carp and allotetraploid hybrids within and after the breeding season were comparatively studied.The result showed that there were six endocrine cell types in the pituitary of these three kinds of fishes,and there was an obvious difference in cell size among different ploidy level fishes.As for the same type of pituitary cells,the cell size was increased gradually with the in-creasing ploidy level.In the breeding season,the allotetraploid hybrids had higher proportion of go-nadotropin cells(GTH)than triploids,and the triploids had higher proportion of GTH than diploids.The results were related to the earlier sexual maturity of allotetraploid hybrids and sterility of triploid cru-cian carp.On the other hand,among the three kinds of fishes,the proportion of somatotropin(STH)cells in triploids crucian carp was the highest,whereas that in allotetraploid hybrids was the lowest.The results might be connected with the faster growth rate of triploids and slower growth rate of al-lotetraploid hybrids.In addition,in GTH cells of meso-adenohypophysis after the breeding season,there were many endocrine particles in triploids,while those endocrine particles were released from the cells in allotetraploids and diploids.This result showed that the sterility of triploid crucian carp might be related to the hormone which was not released from the GTH cells.In a word,the present study indicated that the differences in the structure of pituitary among different ploidy level fishes contributed to their difference in the growth rate and gonadal development.展开更多
Bisexual fertile diploid androgenetic individuals(A_(0))(2n=100)were formed by androgenesis.In this way,the diploid spermatozoa from male allotetraploid hybrids(AT)(4n=200)of red crucian carp(Carassius auratus red var...Bisexual fertile diploid androgenetic individuals(A_(0))(2n=100)were formed by androgenesis.In this way,the diploid spermatozoa from male allotetraploid hybrids(AT)(4n=200)of red crucian carp(Carassius auratus red var.)(♀)×common carp(Cyprinus carpio L.)(♂)were used to fertilize the UV-treated hap-loid eggs of goldfish(Carassius auratus),and living androgenetic diploid fish were developed.The A_(0)became sexually mature at the age of 2 years,and they fertilized with each other to form their offspring(A_(1)).In this study,we observed the chromosomal number,gonadal structure and appearance of A_(1)fish.The results are as follows:(1)In A_(1),there were 85%tetraploids(A_(1)-4n),10%triploids(A_(1)-3n)and 5%diploids(A_(1)-2n),suggesting that diploid A_(0)could produce diploid gametes.It was concluded that the formation of diploid gametes generated from diploid A_(0)was probably related to the mechanism of pre-meiotic endoreduplication.(2)Among A_(1),only A_(1)-4n possessed normal ovaries and testes.The mature males of A_(1)-4n produced white semen.Under the electron microscope,the head of diploid sperm generated by A_(1)-4n was bigger than that of haploid sperm generated by red crucian carp.In the testes of the A_(1)-4n,there were many mature normal spermatozoa with a head bearing plasma mem-brane and a tail having the typical structure of"9+2"microtubules.Between the head and the tail,there were some mitochondria.The ovaries of A_(1)-4n developed well and mainly contained II,III and IV-stage oocytes.The IV-stage oocytes were surrounded by inner and outer follicular cells.The micropyle was observed on the oolemma of follicular cells.There were abundant yolks and plenty of endoplasmic reticulum in the cytoplasm of IV-stage oocytes.Because A_(1)-2n and A_(1)-3n were distant crossing diploid hybrids and triploid hybrids respectively,they possessed abnormal gonads,and no mature semen and eggs were observed.(3)Compared with allotetraploids,the A_(1)-4n fish not only had advantages such as fast growth rate and strong resistibility but also showed some new good performances such as high ratio of body width to body length,smaller heads and shorter tails.These results indicated that an-drogenesis could produce bisexual fertile tetraploids and improve the shape of allotetraploid hybrids as well,which will be of great significance in both the cell genetics research and fish breeding.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.30330480)the State Key Basic Research Project of China(abbreviate:973 Project)(Grant No.2001CB109006)the Doctoral Station of University of the Education Ministry of China(Grant No.200405422001).
文摘The histological and ultra-structure of the pituitary in diploid red crucian carp(Carassius auratus red var.),triploid crucian carp and allotetraploid hybrids within and after the breeding season were comparatively studied.The result showed that there were six endocrine cell types in the pituitary of these three kinds of fishes,and there was an obvious difference in cell size among different ploidy level fishes.As for the same type of pituitary cells,the cell size was increased gradually with the in-creasing ploidy level.In the breeding season,the allotetraploid hybrids had higher proportion of go-nadotropin cells(GTH)than triploids,and the triploids had higher proportion of GTH than diploids.The results were related to the earlier sexual maturity of allotetraploid hybrids and sterility of triploid cru-cian carp.On the other hand,among the three kinds of fishes,the proportion of somatotropin(STH)cells in triploids crucian carp was the highest,whereas that in allotetraploid hybrids was the lowest.The results might be connected with the faster growth rate of triploids and slower growth rate of al-lotetraploid hybrids.In addition,in GTH cells of meso-adenohypophysis after the breeding season,there were many endocrine particles in triploids,while those endocrine particles were released from the cells in allotetraploids and diploids.This result showed that the sterility of triploid crucian carp might be related to the hormone which was not released from the GTH cells.In a word,the present study indicated that the differences in the structure of pituitary among different ploidy level fishes contributed to their difference in the growth rate and gonadal development.
基金Supported by the National Natural Science Foundation of China(Grant Nos.30330480 and 30571444)the Doctoral Station of University of the Education Min-istry of China(Grant No.200405422001)+1 种基金the Agriculture Technological Production Foundation of the Science and Technology Ministry of China(Grant No.2005380)Important Solution Project of Hunan Province(Grant No.2006NK2008)
文摘Bisexual fertile diploid androgenetic individuals(A_(0))(2n=100)were formed by androgenesis.In this way,the diploid spermatozoa from male allotetraploid hybrids(AT)(4n=200)of red crucian carp(Carassius auratus red var.)(♀)×common carp(Cyprinus carpio L.)(♂)were used to fertilize the UV-treated hap-loid eggs of goldfish(Carassius auratus),and living androgenetic diploid fish were developed.The A_(0)became sexually mature at the age of 2 years,and they fertilized with each other to form their offspring(A_(1)).In this study,we observed the chromosomal number,gonadal structure and appearance of A_(1)fish.The results are as follows:(1)In A_(1),there were 85%tetraploids(A_(1)-4n),10%triploids(A_(1)-3n)and 5%diploids(A_(1)-2n),suggesting that diploid A_(0)could produce diploid gametes.It was concluded that the formation of diploid gametes generated from diploid A_(0)was probably related to the mechanism of pre-meiotic endoreduplication.(2)Among A_(1),only A_(1)-4n possessed normal ovaries and testes.The mature males of A_(1)-4n produced white semen.Under the electron microscope,the head of diploid sperm generated by A_(1)-4n was bigger than that of haploid sperm generated by red crucian carp.In the testes of the A_(1)-4n,there were many mature normal spermatozoa with a head bearing plasma mem-brane and a tail having the typical structure of"9+2"microtubules.Between the head and the tail,there were some mitochondria.The ovaries of A_(1)-4n developed well and mainly contained II,III and IV-stage oocytes.The IV-stage oocytes were surrounded by inner and outer follicular cells.The micropyle was observed on the oolemma of follicular cells.There were abundant yolks and plenty of endoplasmic reticulum in the cytoplasm of IV-stage oocytes.Because A_(1)-2n and A_(1)-3n were distant crossing diploid hybrids and triploid hybrids respectively,they possessed abnormal gonads,and no mature semen and eggs were observed.(3)Compared with allotetraploids,the A_(1)-4n fish not only had advantages such as fast growth rate and strong resistibility but also showed some new good performances such as high ratio of body width to body length,smaller heads and shorter tails.These results indicated that an-drogenesis could produce bisexual fertile tetraploids and improve the shape of allotetraploid hybrids as well,which will be of great significance in both the cell genetics research and fish breeding.
