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1983年  第4卷  第1期

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研究论文
Misgurnus anguillicaudatus and Paramisgurnus dabryanus are two common species of mud loaches in Hubei Province.A comparative study of the karyotypes in these two species was carried out with particular considerations on their taxonomy and evolution.The Chromosome preparations for this study were made with short-period PHA-cultured kidney cells in vitro by the air-drying method and Giemsa staining.Misgurnus anguillicaudatas has a diploid chromosome number of 100 with a fundamental arm number (NF) amounting to 128.Ilts karyotype comprises 8 pairs of metacentrics,6 pairs of submetacentrics and 36 pairs of telocentrics.Paramisgurnus dabryanus has 2n=48 with NF=64,which consists of 6 pairs of metacentrics,2 pairs of submetacentrics and 16 pairs of telocentrics.But cells containing 2n of 49 with NF of 65 were also found in some individuals collected from sha shi market.No sex chromosome was fourd in these two species.Basing upon the above mentioned results of karyotype analysis,one may well consider Misgurnus anguillicaudatus as a tetraploid fish which has been formed through a spontaneous polyploidization of chromosome complements from 2n(=50) to 4n(=100).Thus,the 2n of the primitive species should be 50.In fact,the 2n of the Japanese mud loach Misgurnus anguillicaudatas was reported to be 50,which has not been found in China.Regarding the karyotypical differences between Paramisgurnus dabryanus [2n=48(49)] and the supposedly primitive species (2n=50),it might be due to some structural rearrangements such as Robertsonian translocations among chromosomes of the primitive form,which had occurred in the course of karyotypical evolution,resulted in the reduction in chromosome number.A smallest supernumerary chromosome found in Paramisgurnus dabryanus is probably a chromosome.Further studies,however,are needed to substantiate all these propositions.
The karyotype of the Tufted Deer (Elaphodus cephalophus) is first investigated with cultured fibrolasts from the lung and skin of two animals (one male and one female).The diploid number is 48,in the male and 47,in the female.G-band analysis shows that chromosomes 25 and 26 of the male just correspond to the long and short arms of chromosome 24 of the female,respectively.C-band observations shows that a pair of chromosome 23 and a chromosome 24 in the female and a chromosome 23,a chromosome 24 and a chromosome 25 in the male all contain rich heterochromatin.We think that these specific chromosomes probably relate to the sexual determination.The Ag-As technique reveals clearly silver stained spots at the secondary constrictions of two pairs of autosomes 1 and 2.In addition,the spontaneous frequencies of the sister chromatid exchanges (SCE) of this species are calculated.The average SCE number per cell is 6.2.
Rhesus Monkey kidney trypsin-dispersed tissue cells were preserved at -196℃ and resuscitated.The biological characteristics of preserved cells were studied.The results of this study have indicated that cells frozen storage in -196 ℃ from 2-58 weeks,had a survival average rates of 63.3-74.4%.The reconstituted cells showed a good morphological appearance and,in general,required 6-7 days to form a dence monolayer,after rewarning at 37 ℃ for reculture.The cell monolayers were very susceptable to polioviruses.Karyotypes and chromosome analyses and sister chromatid exchange assay were unremarkable.Native dimethylsulfoxid (DMSO) may be used as a cryo-protective agent.
By applying colloidal carbon on anal lips of the chicks,it is found that the carbon particles are endocytized by the follicle-associated epithelial cells of the buras of Fabricius.After 24 hours,the endocytized carbon particles present mainly in the stellate cells and the intercellular spaces in the medulla of the lymphoid follicles.The follicle-associated epithelium (FAE) treated with testosterone propionate (TP) in different developmental stages is found to be damaged.The ultramicrostructure of these cells is changed and endocytosis is apparently inhibited.When TP is treated,especially in higher doses,endocytosis is completely suppressed.In addition,the morphological changes of the FAE treated with TP are observed to be similar tn natural involution of the normal bursa of Fabricius.Thus,the present experimental results give further evidence that natural involution of the bursa of Fabricius in chickens is related to the increasing of the male hormonral concentration in the organism.