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ACTA

ZOOLOGICA

SINICA

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CHINESE

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ACTA ZOOLOGICA SINICA

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Vol. 47 No.1 Jan. 2001

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ABSTRACT

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Sexual selection, extra-pair paternity, genetic variability and conservation

Anders Pape MŚľller^*

(Laboratoire d' Ecologie, CNRS UMR 7625, Universite Pierre et Marie Curie 7 Quai St. Bernard, Case 237, F-75252 Paris Cedex 5, France)

Abstract Sexual selection has been hypothesised to be relaxed on islands, perhaps because island populations often have low levels of genetic variability. I tested whether island population of birds have low genetic variability, whether the rate of mutational input is higher in populations with more intense sexual selection, and whether the intensity of sexual selection as estimated from the frequency of extra-pair paternity is reduced on islands. A pairwise comparison of paternity studies of bird populations in relation to genetic variability as determined by minisatellite band sharing coefficients among unrelated individuals was used to test the prediction that females should engage more frequently in extra-pair copulations in populations with a greater amount of genetic variation. There was a higher frequency of extra-pair paternity in bird populations with a lower band sharing coefficient. A second comparative analysis of pairs of island and mainland populations of birds revealed that extra-pair paternity was consistently lower in island populations, which also had lower genetic variability. This reduced genetic variability was partly due to a reduction in mutational input. These findings suggest that ( 1 ) intraspecific variation in paternity increases with the amount of genetic variability, (2) the mutation rate is higher in populations with greater genetic variability and more intense sexual selection, and that (3) the intensity of sexual selection generally is weaker on islands than on the mainland. This has implications for our understanding of spatial variation in genetic variability and for problems of conservation on islands and in other isolated populations. [Acta Zoologica Sinica 47(1):2-12,2001]

Key words Birds, Band sharing, Islands, Minisatellites, Sexual selection, Sperm competition

*E-mail:amoller@hall.snv.jussieu.fr

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Infraciliature and morphogenesis of Carchesium

polypinum (Ciliophora: Peritrichida)

SHI Xin-Lu YU Yu-He SHEN Yun-Fen

( lnstitute of Hydrobiology , The Chinese Academy of Sciences , Wuhan 430072, China)

Abstract Infraciliature and morphogenesis of Carchesium polypinurn during asexual cycle were studied with protargol technique. The results show: (1) Before the obviousty changed to the macronucleus in morphology, the germinal field for new buccal ciliary organelles became being with the kinetosomes in the front of the germinal row proliferating. With the development of the kinetosomes within the field, the peniculus 2 and 3 are formed, later the new haplokinety appeared, while the old haplokinety generated or duplicated the new peniculus 1. Both the new peniculus 1 and the old haplokinety separated at the telophase. The two germinal rows (GK') for both the daughter cells appeared almost at the same time; (2) The macronucleus became shorter and thicker, finally oblate during the division of the cell. Then the macronucleus restored its original shape, band-like form. The micronucleus were divided into two before the macronucleus division; (3) The original scopula and stalk contributed to the old cell. The new cell formed scopula gradually after the cell division. [Acta Zoologica Sinica 47(1):13-18,2001]

Key words Peritrichida, Ciliate, Carchesium polypinurn, Infraciliature Morphogenesis

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Observation on liver of oncomelania snails under

optical and electron microscope

XIA Quan-Bin TAN Pei-Ping

(Institue of Parasitic Diseases , Yueyang 414000, Huanan, China)

PENG Long-Xiang ZHANG Shu-An

(Department of Electron Microscope, Hunan Medical University, Changsha 410078, China)

Abstract We studied the micro- and ultramicro- hepatical structure of Oncomelania snails. The results showed that the hepatical glandulous tubes were composed of simple columnar epithelis and cellular polarity was quite strong, cellular organs were well developed, rough endoplasma recticulium distributed around cellular nucleus in the shape of polylayer and platelayer. The shape of mitochondrion had ellipse and rhabditi form, and Golgi's body and lysosome were in the upper of the nucleus. There were four kinds of secretory granules in the cytoplasma granules high electron density in the base of cell, macro granules in the middle, large and small granules which could release into glandulous tube together with cytoplasma near by the free end; skein cells were simillar to triangle and there are blood cells and capillary cave seen in the hepatical interstice. [Acta Zoologica Sinica 47(1):19-26,2001]

Key words Oncomelania, Liver, Microstructure, Ultromicro structure, Simple columnar epithelium, Cellular organ, Secretory

E-mail:hnpara@mail.yy.hn.cn

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MICROSTRUCTURE AND ULTRASTRUCTURE OF THE SINUS GLAND

IN THE EYESTALK OF ERIOCHEIR SINENSIS

SUN Jin-Sheng^˘Ů* LIU An-Xi^˘Ú DU Yu-Zhe^˘Ű GU Jing-Ling^˘Ű

( ˘Ů lnstitute of Oceanology , Academia Sinica , Oingdao 266071, Shandong , China)

( ˘Ú Department o~ Biology , Nankai University, Tianjin 300074, China)

( ˘Ű Department of Fishery, Tianjin Agricultural College, Tianjin 300381, China )

Abstract Cultured larvae, matured and precocious matured Chinese mitten crab (Eriocheir sineasis ) were obtained from Renfeng farming Co. in Tianjin, kept in recirculated tap water. The sinus glands (SG) were dissected under ice-chilled saline at the transition of the medulla interna and medulla terminalia dorm-laterally in the eye-stalks of the specimens of the three kinds of crabs (2.1 ĄŤ2.3cm, 3.8ĄŤ4.3, 5.1ĄŤ5.4cm carapace width of larvae, matured and precocious matured crabs). For a light-microscopic overview, SGs were fixed in Bouin fluid and Chrome-hematoxylin staining was performed. For fine structural analysis, SGs were immediately fixed in the 4% Glutaraldehyde in 0 .7mol/L sucrose and 5mmol/L CaC12 for 3ĄŤ4 h, followed by postfixation in 1% osmic acid in 0.45mol/L sucrose and 5mmol/L CaCI2 for 1.5h. After dehydration and embedment, ultrathin sections were cut on a LKB-Ultrotome V and examined with Philips EM400ST electron microscopic.

Our results suggest that the SG of the Chinese mitten crab is a roughly ellipsoid structure which is mainly composed of enlarged axon terminals abutting on the thin basal lamina of a central hemolymph lacuna acting as a storage release centre for the membrane bound neurosecretory material. Also present in the SG are glial cells with cytoplasmic processes which enwrap the terminals. Six types of neurosecretary terminals were distinguished on the basis of size, morphology and electron density of the neurosecretory granules. Each axon terminal contained 1 type of granule despite of type V ~ The mean granule diameter ranged from 97nm(type IV ) to 258nm(type I ). Type 3 and type 6 axon terminals were, respectively, the most and least frequent. Neurosecretory granules exocytosis from the terminals were observed in the sinus gland of the Chinese mitten crab. Large multi-lamellate bodes appeared in terminals depleted of neurosecretory granules and maybe involved in the recycling of granules membrane. Some images showed that glial cells were involved in neurosecretion. The comparison between larvae and matured or precocious matured crabs was demonstrated. [Acta Zoologica Sinica 47(1):27-31,2001]

Key words Crustacea (Eriocheir sinensis), Sinus gland, Ultrastructure, Precocious mature, Neurosecretion

*E-mail:jinshengsun@263.net

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The cell types and secretion of the digestive gland in

Haliotis discus hannai ino

CUI Long-Bo^* LIU Chuan-Lin LIU Xun LU Yao-Hua

( Department of Biochemistry , Yantai University, Yantai 264005, Shandong , China )

Abstract Histology, histochemistry, ultrastructure and activity of some hydrolytical enzymes of the digestive gland of Haliotis discus hannai Ino have been studied. The gland consists of two types of cells, digestive cells and basophilic cells. The digestive cells are capable of ingesting exogenous material from the lumen of the tubule, and contain a number of vesicles concerning with the heterophagic function of the cells. The vesicles exhibit considerable variation in size and appearance in different regions of the cells. Those in the apical and sub-apical regions of the cells, which are considered as heterophagosomes, are involved in accumulation of the ingested material. Those in the mid-regions, regarded as heterolysosomes, give a positive reaction to tests for acid phosphatase and non-specific esterase. They concern with intracellular digestion of the ingested material. The vesicles in the basal regions, considered as residual bodies, are involved in accumulation of undigested and indigestible residues. The digestive cells secrete proteinase. Numerous lipid globules in the cells show that the digestive cells can reserve food material. The basophilic cells are characterized by the possession of a well-developed rough endoplasmic reticulum and many refractile spherules which give a intense reaction to test for iron. The cells also secrete proteinase. The refractile spherules which contain metals may serve a detoxification function. The tests for enzymatic activity in vitro show that the digestive gland is positive for diastase, cellulose, aliginase and laminarinase. [Acta Zoologica Sinica 47(1):32-37,2001]

Key words Haliotis discus hannai Ino, Digestive gland, Histology, Histochemistry, Ultrastructure, Hydrolase

*E-mail:glbio@ytu.edu.cn

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Evolutionary relationships among CHINESE Ranid frogs inferred

from mitochondrial dna sequences of 12S rRNA gene

JIANG Jian-Ping^* ZHOU Kai-Ya

( Biocliversity and Molecular Evolution Laboratory, Department of Biology, Nanjing Normal University, Nanjing 210097, China )

Abstract Approximately 400 base pairs of the mitochondrial 12S rRNA gene from 24 species of Chinese ranid frogs(Table 1) were sequenced. Phylogenetic analyses of these data using neighbor-joining method showed that these frogs were divided into three lineages. The first lineage (BCL 78 % ) contains 7 species, Fejervarya limnocharis , Hoplobatrachus rugulosus , Limnonectes fujianensis , Paa boulengeri , P. spinosa , P. robertingeri , and Nanorana pleskei, of which 3 species of Paa forming a monophyletic group (BCL 99% ). The second lineage (BCL 99% ) comprises 3 species, Amolops daiyunensis, A. ricketti, and A. wuyiensis, coresponding to the subfamily Amolopinae. The rest 14 species belong to the third lineage (BCL 61% ), of which 5 species of Rana and 4 species of Odorrana forming a monophyletic group respectively. Two species of Pelophylax cluster together before they cluster with the genus Hylarana. Two species of Rugosa form a clade before they cluster with the monophyletic group of 5 species of Rana. The second and third lineage cluster at BCL = 85 %, and a

sister group relationship between the cluster and the first lineage is recognized. In other words, the first lineage comprising 7 species of the subfamily Raninae and the third lineage comprising 14 species of the subfamily Raninae do not cluster directly. This result suggests that the frogs of the first lineage are probably excluded from the subfamily Raninae. In addition, the molecular evidence supports the establishment of ranid genera Fejervarya, Limnonectes, Hoplobatrachus, Paa, Odorrana, Rugosa and Pelophylax. They were separated from the genus Rana which now represent only Brown frogs. [Acta Zoologica Sinica 47(1):38-44,2001]

Key words Ranidae, Molecular phylogeny, mtDNA, 12S rRNA gene

*E-mail:jjplxz@163.net

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Influences of thermal and hydric environments on incubating eggs and resultant hatchlings

in a colubrid snake(Xenochrophis piscator)

JI Xiang DU Wei-Guo XU Xue-Feng

(Department of Biology, Hangzhou Normal College, Hangzhou 310036, China)

Abstract Influence of thermal and hydric environments on incubating eggs, embryonic use of energy and hatchling characteristics were studied in a colubrid snake, Xenochrophis piscator. All viable eggs increased in mass over the course of incubation because these eggs absorbed water from surroundings, and mass gain during incubation was dependent on initial egg mass and substrate water potential. Duration of incubation, hatching success, embryonic use of nutrients and energy and sex ratio, size and mass of hatchlings were unaffected over a wide range of substrate moisture. Duration of incubation decreased as incubation temperature increased. There was a strong family effect on incubation length. Incubation temperature did not determine sex of hatchlings, but profoundly affected hatching success, embryonic use of nutrients and energy, size and mass of hatchlings, carcass mass and post-hatching yolk mass. There was no significant difference in total length (SVL plus TL) between female and male hatchlings, but the newborns did exhibit sexual dimorphism in snout-vent length and tail length, with females having longer SVL and shorter TL than did males. 3212 was not a suitable temperature for incubating X.piscator eggs for two reasons: (1) eggs at 3212 produced hatchlings with less developed carcass, greater amount of unutilized yolk and abnormal tail; (2) embryos expended more energy at 3212 than at lower temperatures to complete development. Given that eggs at 2412 and 2612 both produced well-developed hatchlings of which the measured variables were nearly the same for the newborns from the two temperatures, we conclude that 2612 is the best incubation temperature for X. piscator in this study. [Acta Zoologica Sinica 47(1):45-52, 2001]

Key words Xenochrophis piscator, Egg, Incubation, Hatchling

*E-mail:xji@mail.hz.zj.cn

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Density dependent growth and population management

strategy for Pere David's deer in China

JIANG Zhi-Gang^*

(Institute of Zoology, The Chinese Academy of Sciences, Beijing 100080, China)

ZHANG Lin-Yuan XIA Jing-Shi YANG Rong-Sheng RAO

( Beijing Milu Park , Beijing 100076, China)

DING Yu-Hua SHEN Hua XU An-Hong

(Jiangsu Dafeng Milu National Nature Reserve, Dafeng 224136, Jiangsu, China)

YU Chang-Qing

( Institute of Forestry Resource, Chinese Academy of Forestry, Beijing 10009, China)

Abstract Since the reintroduction of the P¨¨re david's deer in China in mid 1980's, the Beijing and Dafeng P¨¨re david's deer breeding populations have been established. During the past 14 years, the Beijing and Dafeng populations all experienced the periods of acclimatization and population growth. By the end of 1997, the total number of the P¨¨re david's deer reached 671 in China. The sex ratios in both Beijing and Dafeng P¨¨re david's deer reached balanced sex ratios and the effective population sizes also approached to sizes of the actual population in both populations. However, the carrying capacity of the Beijing Milu Park is limited, the P¨¨re david's deer in the Dafeng P¨¨re david's Deer Natural Reserve are mainly living in three paddocks of lkm², thus, population densities increased as the populations grew. In the 1990's, the growths of both Beijing and Dafeng populations showed density-dependent patterns, especially in the Beijing population. Hence, population regulation measures such as artificial dispersal and controlling of birth rate must be taken in order to slow down the rapid growth in the Beijing population. There is vast seashore in the Dafeng P¨¨re david's Deer Natural Reserve. Captive-bred P¨¨re david's deer can be released into open coast area and to reestablish wild P¨¨re david's deer population, thus, to reduce grazing pressure by P¨¨re david's deer in the paddocks. The relocation of P¨¨re david's deer to Tianezhou, Shishou, Hubei is met with a success. The relocated P¨¨re david's deer adopted the climate of the lower reach of the Yangtze river, now the population of the Tianezhou reserve is over 200, the population growth rate is 35 %. That means the lower reach of Yangtze river is suitable for further field release of the P¨¨re david's deer. When considering manipulating population structure and releasing captive-bred individuals to the field, we should also keep a group of P¨¨re david's deer in captivity, to continue the process of domestication of the deer. Therefore, while restoring the P¨¨re david's deer in the nature, we will also produce a domestic P¨¨re david's deer breed, which can be farmed in the future. [Acta Zoologica Sinica 47(1):53-58,2001]

Key words Elaphurus davidianus, Population regulation, Wildlife captive breeding, Ex situ conservation, Reintroduction

*E-mail:jiangzg@panda.ioz.ac.cn

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Purification and characteristics of haemolymph

lectins in Sarcophaga peregrina larvae and pupa

PEI Yan LU Xiao-Feng YANG Xing-Yong KONG Yi-Fei CHENG Jing-Qiu JIANG

( Biotechnology Research Center, Southwest Agricultural University, Chongqing 400716, China)

Abstract Lectins in haemolymph of Sarcophaga peregrina larvae and pupa were purified by affinity chromatography. Antiserum against larvae haemolymph lectin and two glycoproteins, fetuin and thyroglobulin, were used as affinity ligands for purification of larvae lectin. SDS-PAGE results indicated that, the lectin purified from larvae haemolymph was a monomer with molecular weight (Mr) around 73kD; while the lectin from pupa was composed of two subunits, with Mr 30 and 33 kD, respectively. The carbohydrates, which inhibited haemag-glutination activity (HA) in haemolymph of larvae and pupa, were different. It showed that HA was inhibited by lactose, fucose and N-acetylgalactosamine in the larvae, and inhibited by mannosamine, glactosamine and glucosamine in the pupa. The antiserum against larvae lectin had no cross reaction to the pupa lectin. It was suggested that the leetin purified from larvae is different from that in pupa. Compared with the other studies on S.peregrina lectins, the inhibiting sugars to the pupa lectin activity as revealed in this study were quite different from those existed in pupa and wounded larvae reported by Komano et al., although the subunites Mr of the former were the same as that of the latter. [Acta Zoologica Sinica 47(1):59-63,2001]

Key words Sarcophaga peregrina, Lectins, Purification, Characterization

*E-mail:peiyan@swau.edu.cn

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Combined toxicities of dioxins indicated by erod in rat hepatoma cells in vitro

LI Wen XU Ying WU Wen-Zhong

(State Key Laboratory of Freshwater Ecology and Biotechnology,Institute of Hydrobiology,The Chinese Academy of Sciences,Wuhan 430072,China)

K. -W. Schramm A. Kettrup

( GSF-National Research Center for Environment and Health, Institute of Ecological Chemistry, Germany)

Abstract Polyhalogenated aromatic hydrocarbons (PHAHs) such as polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and biphenyls (PCB) are persistent environmental pollutants, which are able to bioaccumulate through the food chain and pose a series health risk to humans and animal species. Since the environmental biota is exposed to mixtures of these compounds rather than to the single congener, simultaneous or sequential exposure of organism to two or more these compounds may alter quantitative and qualitative biological response. Therefore, studies with mixtures could provide more information about the possible interactive effects between these compounds and the fundamental mechanisms behind these interactive effects.

In this study, the activities of five individual PHAHs (TCDD, TCDF, OCDD, PCB77 and PCB126) and their mixtures as inducers of ethoxyresorufin-O-deethylase (EROD) in rat hepatoma H4IIE cells were determined. The EROD activity in intact cells seed on 96 well plates was determinated according to Donato et al.modified as follows: Cells were seeded at a density of 1 x 10 4/well in a 96-well plate. After 3 days the medium was replaced with 100ŚĚl medium containing samples extract or TCDD standard. After 72hr the medium was removed and 100ŚĚl fresh medium containing 8 ŚĚmol 7-ethoxyresorufin and 10 ŚĚmol dicumarol were added. After incubation for 60min at 37Ąć the medium was transferred to a fresh 96-well plate and 130ŚĚl methanol were added. Resorufin-associated fluorescence was measured in these solutions on a multiwell fluorescence reader. The 96-well plate containing the remaining live cell cultures was for a cytotoxicity test using the neutral red assay, Thereafter the protein content per well was assayed using bicinchoninic acid. Standard deviations between triplicates remained < 10 %

In EROD bioassay, The individual EC50-values and toxic equivalency factors (EROD-TEFs) for TCDF, OCDD, PCB77 and PCB126, were in good agreement with international TEFs(I-TEFs). Toxic effects of 2, 3, 7, 8-TCDD alone and in the presence of 2, 3, 7, 8-TCDF, OCDD, PCB126, PCB77 as inducers of ethoxyresorufin-O-deethylase (EROD) in rat hepatoma H4IIE cells were assessed by TEF and independence model respectively. The results from TEF showed that the difference between the experimental and calculated TEQs for these mixtures was minimal while the interactions were perfectly additive. These were in good agreement with the results from the model assessment. This study not only confirms the utility of the TEF approach and the feasibility of the modelling, but also indicates that the in vitro induction assay is useful for mixtures. [Acta Zoologica Sinica 47(1):64-70,2001]

Key words Combined toxicities, Dioxins, Rat heptoma cells, EROD induction

*E-mail:nicel@21cn.com

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Sex reversal and gonadal development of triploid rainbow trout(Oncorhynchus mykiss)

DENG Glenn Y.^*

(Department of Biological Sciences,Stanford University, Pacific Grove, California 93950, U. S. A. )

CHEN Li-Qiao

(Department of Biology, East China Normal University, Shanghai 200062, China )

WANG Xue-Ming

(Fisheries College, Central China Agricultural University, Wuhan 430070, China)

OSHIRO Takashi TAKASHIMA Fumio

(Department of Aquatic Biosciences, Tokyo University of Fisheries, Konan , Minato , Tokyo, 108, Japan )

Abstract Juvenile triploid Rainbow trout ( Oncorhynchus mykiss ), obtained by heat shock of fertilized eggs, were orally administered 17ŚÂ-estradiol at concentrations of 0 ĄŤ60 ŚĚg/g diet, for 60 days following first feeding. The control group was comprised of 52 % female and 48 % male, whereas the test group (including phentotypical males undergone sex reversal) comprised 93-100 % female fish. Gonadal development was determined in the 1- 3 years old females and males. In the testis of triploid males, spermatogenesis was observed suggesting male triploids eventually mature, whereas the oocytes of triploid females were retarded at the zygotene to pachytene (chromosome pairing) stages suggesting that the ovaries of triploid females were undeveloped. On the other hand, oocytes of triploid were not developed later than the peri-nucleolus stage and no mature triploid female was observed. These results suggest that the sterility in triploid female sterility may not be caused by genomic differences between male and female. The growth and survival rates two months after hormone treatment were the same in the treated and control groups, suggesting that the hormone treatment did not make a significant difference to early growth and survival. Our results suggest that triploid females, including the sex reversed males, were completely sterile and 17ŚÂ-estradiol treatment to induce sex-reversal may be useful for creating all-female sterile fish. [Acta Zoologica Sinica 47(1):71-78, 2001, in English]

Key words Rainbow trout (Oncorhynchus mykiss), Polyploid fish, Sex reversal, 17ŚÂ-estradiol, Gonadal development

*E-mail: yaguangdeng@yahoo.com

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A comparative of sperm proteins between males from gynogenetic

and gonochoristic Crucian carp

YANG Shu-Ting GUI Jian-Fang

( State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology,

The Chinese Academy of Sciences, Wuhan 430072, China)

Abstract In order to reveal the difference of sperm proteins between males from gynogenetic Silver crucian carp( Carassius auratus gibelio) and gonochoristic transparent Color crucian carp ( Carassius auratus transparent colored varity), the two types of sperm were respectively extracted by the same methods at same conditions, and various fractions were collected. The fractions include sperm plasma, sperm head membrane, flagella, and demembranated sperm head.

The soluble protein components of these extracted fractions and the whole sperm were analysed by means of different polyacrylamide gel electrophoresis system, such as nondenaturing polyacrylamide gel eleetrophoresis, SDS-PAGE and Acid-Urea PAGE system. The obtained results show that each fraction contains specific soluble protein components, and a few of soluble proteins are different in some fraction between gynogenetic Silver crucian carp and gonochoristic Color crucian carp. The protein components of sperm plasma are different not only between the two kinds of fishes, but also among the individuals in the same kind of fish. It is suggested that the difference of sperm plasma proteins could be resulted from the contamination of blood and body fluid.

In the flagella fraction, one soluble protein component specific for gynogenetie Silver crucain carp was observed by SDS-PAGE system. The soluble protein components in sperm head membrane fraction were analysed by SDS-PAGE system and nondenaturing PAGE system, and found that they have same patterns in SDS-PAGE system but various pattern in nondenaturing PAGE system. It was suggested that the difference might be related to complex and functional status of the head membrane proteins. The significant difference of the soluble protein components between two types of fishes were discovered in demembranated sperm head fraction. Several protein bands specific for gynogenetic Silver crucain carp were revealed by SDS-PAGE analysis. Furthermore, the specific proteins were demonstrated to be basic proteins by Acid-Urea PAGE system. These discoveries laid a foundation for identifying specific proteins and revealing the mloe cular mechanism in gynogenetic Silver crucian carp sperm [Acta Zoologica Sinica 47(1):79-84, 2001]

Key words Gynogenesis, Sperm proteins, Sperm head, Sperm membrane, Flagella, Fractionation

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Effects of ethanol on the development of mouse preimplantation embryos in vitro

FAN Heng-Yu YANG Zeng-Ming

(Department of Biotechnology, Northeast Agricultural University, Harbin 150030, China)

Abstract Mouse embryos at the stage of 2-cell, 4-cell, 8-cell and morula were cultured in Whitten's medium to study the effects of ethanol on the developmental embryo. Tolerance threshold of 2-cell mouse embryos to ethanol was around 1.5% when these embryos were cultured in Whitten' s medium with 0, 0.1%, 0.5 %, 1.0 %, 1.5 %, 2.0 %, 3.0 %, 5.0 % and 10.0% ethanol, respectively. Then the mouse embryos at the stage of 2-cell, 4-cell, 8-cell and morula were cultured in Whitten's medium with 1.0% and 3.0% ethanol to see the sensitivity of mouse embryos to ethanol. The results suggested that 1.0% ethanol appeared to have benefidal effects on the cavitation of 8-cell embryos and morula. However, the effects of 1.0% ethanol on 2-cell and 4-cell embryos were not so obviously. Embryonic development at the stage of 2-cell, 4-cell, 8-cell and morula was more or less inhibited by 3.0 % ethanol. Tolerance of embryos to ethanol becomes stronger in late developmental stages of the embryo. [Acta Zoologica Sinica 47(1):85-88, 2001]

Key words Mouse, Embryonic development, Ethanol

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Genetic variation revealed of two loach species by RAPD analysis

CHANG Zhong-Jie ZHOU Rong-Jia YU Qi-Xing

(College of life sciences, Wuhan University, Wuhan 430072, China)

Abstract Inter- and intra-population genetic variation of Misgurnus anguillicaudatus and Paramisgurnus dabrganus, from middle reaches of Huanghe, Changjiang and Zhujiang rivers, were analyzed using RAPD makers. The results showed that: the average band sharing coefficient of conspecific populations is 0.730ĄŤ0.938, the corresponding genetic distance is 0. 089ĄŤ0. 245; the average band sharing coefficient of interspecies populations is 0.392ĄŤ0.505, the corresponding genetic distance is 0.620ĄŤ0.800. The average band sharing coefficient of Wuhan samples is lower than the that of other populations. It indicated that the genetic distance among individuals of Wuhan population is higher. No sex-specific fragments were found in the two loaches. [Acta Zoologica Sinica 47(1):89-93, 2001]

Key words Misgurnus anguillicaudatus, Paramisgurnus dabrganus, Population genetic variation, RAPD

*E-mail: zhjch@public.xxptt.ha.cn

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EFFECTS OF DIFFERENT NUTRITIONAL STATUS ON EXPRESSION OF

IGF-I mRNA IN IMMATURE COMMON CARP LIVER

HUA Yi-Min LIN Hao-Ran^*

(College of Life Sciences, Zhongshan University, Guangzhou 510275, China)

Abstract Effects of three kinds of nutritional status on tissue IGF-I mRNA expression in juvenile Common carp(Cyprinus carpio) were studied by prolonged outdoor feeding. One group of fish was fed with food containing 40% Casein (H group); another group was fed with food containing 20% Casein (L group). Two kinds of food contain the same amount of energy. The last group of fish was fasted until the 32th day, then fed with food containing 40 % Casein (Starvation group). During the experiment, the growth of starved fish was less than half of that of the L group fish on the 32th day, though no significant change of IGF-I mRNA amount in other tissues was observed. Growth and hepatic IGF- I mRNA level in fasted fish began to gradually be restored after being fed again with food containing 40 % Casein. Like previous studies by other researchers, during starvation the serum growth hormone level increased significantly and two-week refeeding restored it to normal. Even though the growth rate in L group fish was lower than that of H group fish, no statistically significant difference was found between the two group fish after 40 day's feeding. Also, no obvious differences in the serum growth hormone level and hepatic IGF-I mRNA amount between the two group was discovered even on the 32th day. The results suggest that in juvenile Common carp, live in other fishes and mammals, nutrition should be also a regulator of the hepatic IGF-I mRNA expression. Lack of nutrition depresses the hepatic IGF-I mRNA expression, which was most likely to lead to the decrease of serum IGF- I level, and the latter in turn retard growth in juvenile Common carp. When the nutrition was restored, the hepatic IGF-I mRNA was also restored, which would probably lead to the restoration of growth. The results suggest the non-hepatic IGF-I mRNA expression should be independent of the nutritional status as in other reported fishes. In addition, because no differences in growth status and hepatic IGF-I mRNA expression were observed between H group and L group on the 32th day, it is conceivable that the total energy of food may be an important factor in modulate hepatic IGF- I mRNA expression as reported in mammals, and the food containing normal energy and 20 % Casein already can maintain a high level of hepatic IGF-I expression. Alternatively, 32 days perhaps is not long enough for the two nutritional status to show fully the different effects on hepatic IGF- I mRNA expression of the two group of fishes [Acta Zoologica Sinica 47(1):94-100,2001]

Key words Common carp, IGF-I , Nutrition, Growth, Starvation

*E-mail: ls32@zsu.edu.cn

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A method to construct the life table for right-censored and left-truncated data

YAN Xin-Rong WANG Meng-Jun WANG Guang-He LIU Wei ZHONG Wen-Qing

( State Key Lab of Integrated Management of Pest Insects & Rodents,

Institute of Zoology, The Chinese Academy of Sciences, Beijing 100080, China )

Abstract The left-truncated data is a special type of life data in survival studies. It means that some individuals were captured at some know time after they were born. The traditional product-limit estimation method can only deal with complete data and right-censored data, but can not deal with left-truncated data. In this paper, we proposed a revised product-limit estimation that can use the useful survival information contained in the left-truncated data when doing survival analysis. A case study to construct the cohort life table illustration that how to apply this new method in constructing the cohort life table of Microtus brandti by using this new method was also presented here. [Acta Zoologica Sinica 47(1): 101-107,2001]

Key words Survival analysis, Complete data, Right-censored data, Left-truncated data, Product-limit estimation

*E-mail: xwan@public.east.cn.net

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A survey on the horseshoe crabs in the north of south China Sea

LIAO Yong-Yan^˘Ů* HONG Shui-Gen^˘Ú LI Xiao-Mei^˘Ů

( ˘Ů Fisheries College of Zhanjiang Ocean University, Zhanjiang 524025, Guangdong , China )

( ˘Ú Laboratory of Cell Biology, Xiamen University, Xiamen 361005, Fujian , China )

Abstract The northern sea area of the South China Sea is situated between 107.5ĄăĄŤ122.5ĄăEast longitude and 17ĄăĄŤ25ĄăNorth latitude with high temperature and a large quantity of rainfall which belongs to the oceanic climate of the torrid zone and subtropical zone. From September, 1994 to June, 1998, during the research on the species of Horseshoe crab within the scope between the south from North gulf and the north to Xiamen, choosing Xiamen, Shantou, Wuchuan, Donghaidao and Qishui as fixed positions and irregularly going to Xuwen and Suixi in Guangdong province and Fangcheng in Guangxi province, we found that there was only Tachypleus tridentatus in the northern sea area of the South China Sea and the sea area from Wuchuan to Xiamen, and found that there were two species of horseshoe crab which were Tachypleus tridentatus and Carcinoscorpius rotundicauda in the southern area to East Sea Island, referring to East Sea Island, Qishui, Xuwen, Suixi and Fangcheng, most of which were Tachypleus tridentatus, and found a great number of larvae of Tachypleus tridentatus including zooids with different sizes from 7cm bodily length to mature. In Minan we found not only big colonies of adult Carcinoscorpius rotundicauda, but also a great number of larvae of Carcinoscorpius rotundicauda with different body size from 7cra body length to maturity. All these show that the northern sea area of the South China Sea is the area where both Tachypleus tridentatus and Carcinoscorpius rotundicauda distribute and reproduce. On January 1st, 1998 at the town of Qishui in Leizhou, we found an adult male Horseshoe crab and majority of its eggs was immature, while the eggs with above 4mm diameters were only 0.87 percent but the eggs with below 1.0mm diameter was 58 percent (1160 pills). It shows that Qishui is a place where Tachyplers tridentatus survive in the winter. [Acta Zoologica Sinica 47(1): 108-111,2001]

Key words Horseshoe crab, Tachypleus tridentatus, Carcinoscorpius rotundicauda, The South China Sea Species, Distribution,

*E-mail: xwan@public.east.cn.net

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Morphology of the cortical reaction in the eggs of Penaeus penicillatus

WANG Yi-Lei^˘Ů* ZHANG Zi-Ping^˘Ú CHANG Lin^˘Ů LI Shao-Jing ^˘Ű

(˘Ů Institute of Aquaculture Biotechnology, Jimei University, Xiarnen 361021, Fujian , China )

( ˘Ú Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong)

( ˘Ű Oceanography Department, Xiamen University, Xiamen 361005, Fujian, China)

Abstract Morphology of the cortical reaction in the eggs of Penaeus peniciUatus was studied with the light microscopy, scanning electron microscopy and transmission electron microscopy. The cortical reaction is divided into four stages. These stages are unreacted stages, early stages, corona stages and dissipation stage. The cortical rods were released and formed a jelly coating around the surface of the egg. The jelly coating remained until the first cleavage had finished. In the end, the hatching membrane appeared around the egg. It is believed that these cortical reactions are responsible for the prevention of polyspermy by both a chemical and physical block and that also may establish a microenvironment inside a touch chorionic membrane for the developing embryo.

Key words Penaeus penicillatus, Egg, Cortical reaction, Morphology

*E-mail:ylwang@jmu.edu.cn

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