Silkworm，i.e. Bombyx mori, as the typical representative of lepidopteran insect and the ideal biological model，has played a significant role in promoting the development of animal science, which specific mutation has already been the optimum material for the research on modern genetic engineering. With the accomplishment of the draft of the silkworm genome and the fine map, silkworm will further become a comparatively ideal model organism in the field of research on life sciences in postgenome era. This text summarized the silkworm’s contributions to the modem genetics; again, analyzed the status quo of silkworm as the model organism in researching realms of developmental biology, bioreactor, and the construction of molecular platform of genome and so forth; and finally, discussed the application of silkworm being the model organism in the field of Modem Biology.

Objective To compare the biological characteristics of spontaneous type 2 diabetic C57BL/KsJ-db/db mice in growth curve, glucose metabolism, serum insulin, weight of major organs，and organ coefficient with C57BL/Ks J-db/+ mice as the control, then the morphologic changes of the liver, kidney and pancreas were observed. Methods Forth weeks old mice were used with total of twenty weeks experimental period, the weight and glucose at each week, serum insulin at every two weeks were measured. After the experimental period, the mice were sacrified, and the organ and fat were weighted. The pathological changes of the liver, kidney and pancreas were observed. Results ① The weight, glucose and serum insulin of db/db mice were higher than those of the control group at the same age( P P<0.01). But the spleen，pancreas and kidney was less relatively, especially of the spleen and pancreas in female mice( P<0.01).③ The liver appeared significant cell putrescence, adipose degeneration, inflammatory cell infiltration and fibroplastic proliferation in db/db mice. The renal interstitial appeared hyperaemia, dropsy, hyaline cast in renal tubules, and adipose degeneration of epithelial cell. At the same time，the number of glomeruli pancreatici and islet cells decreased obviously. Conclusions The db/db mice is a suitable disease model of type 2 diabetes mellitus, which shows hyperglycemia, high insulin resistance，insufficiency of islet function, renal and hepatic alterations.

Super ovulation in inbred mice can provide a lot of embryos for the establishment of mouse embryo cryobank.Pregnant mare serum gonadotropin and human chorionic gonadotropin were used for the superovulation in BALB/c and C 57 BL/6 A mice, satisfactory results were obtained by the addition of more than 1 μg of 15-methyl prostaglandin F 2α according to the characteristics of the mouse strains. The results show that the average usable embryos obtained from one superovulated BALB/c and C57BL/6 A mouse are 22 and 23 respectively, but only 7 and 8 in control animals. The pregnancy rate is higher in the treated mice than the controls.

Objective To establish TAFA2 gene knockout mouse model and to create the condition for further in vivo study of its biological function and its role of development and growth in central nervous system. Methods The mouse genomic DNA sequence of TAFA2 gene was verified through bioinformatic analysis. According to the TAFA2 genomic DNA sequence, the strategy of gene targeting and constructing of knockout vector (pBR322-MK-MCS-TAFA2) were established. The knockout region spans from exon 4 to 5 of TAFA2 gene in mouse genome. The gene knockout vector pBR322-MK-MCS- TAFA2 was constructed and confirmed by restriction enzyme digestion and sequencing.Electroporation of ES cells with pBR322-MK-MCS- TAFA2 and screening of both G418 and Ganciclovoir resistant clones were performed according to common protocol. The homologous recombined ES cell clones were identified by PCR. Results After transplantation of homologous recombined ES cells into blastocysts through microinjection and mating of chimeras with C57BL/6J mice, 41 offspring with Aguoti fur in color were acquired, 14 of them (34.1%) show heterozygous genotype for TAFA2. Some heterozygote mice were intercrossed to generate mutant homozygotes. Finally, the cohort of mutant homozygotes for TAFA2 were established. Any abnormal change was not found by preliminary observa-tion of phenotype for heterozygous and homozygous mice. Conclusions The TAFA2 gene knockout mice have been established. The embryonic lethality in homologous mutant mice was not occurred.

Objective To research on the intrahepatic biliary system in the zebrafish, Brachydanio rerio. Methods By using enzyme histochemical characterization, immunohistochemistry and electron microscopy. Results The biliary system was arranged in arborization in the parenchyma.The biliary tree included sequentially by intracellular and intercellular canaliculi，preductules,ductules and ducts.The intercellular originated at the neighborhood of the nucleus to extend to the cell surface where it emptied into the intra parenchymal biliary passage running in the interhepatocytic space. In the preductules，the wall was formed by bile preductular epithelial cells and hepatocytes .The bile preductular epithelial cells were linked to hepatocytes by the tight junctions. The wall of the biliary ductule usually consisted integrally 2 to 4 biliary epithelial cells. These cells had no basal lamina and were contacted with hepato-cytes directly. A ductule that was composed of a single cell and was embedded between two adjoining liver cells was found by TEM. The lumen of this ductule was very narrow and formed by the infolding of the plasma membrane of the ductule cell. The wall of bile ducts was composed of cuboidal epithelial cells, and the bile duct was encircled by the connective tissue. Whereas in ducts, apart from those cells，there were intraepithelial lymphocytes.This suggested that there exited mucosal immune response. The preducules and ductules formed a segment connecting canaliculi to ducts, thus, we considered that segment as being analogous to the mammalian canals of Hering.The reactions for Mg ²⁺-dependent ATPase showed that bile tree was strained brownish-black color and interwove into a network. The bile system was revealed by immunstaining with a monoclonal antibody 2F11 that detected biliary epithelial cell bodies which are distributed scattcrcdly in interhepatocytic and the proximal regions of the ducts arising from these cells was stained. Conclusions The bile systerm in zebtafish is not only different with the mammals and birds, but also with other bony fish.

Objective To measure the organ weight and organ coefficient of WHBE rabbits. Methods The weight of body and main organs of adult WHBE rabbits were measured and calculated their organ coefficient, and compared between male and female in this experiment. Results Between male and female, the thyroid gland weight and coefficient showed significantly differences ( P＜0.01)，but no difference was seen in the other organ coefficient (p>0.05). Conclusion The above data could be useful in the biomedical researches.

Laboratory rabbit is an important species in laboratory animals, mainly used in pharmaceuticals,pyrogen testing of biotechnology products，the preparation of antiserum, skin irritation test，the optic nerve，microbiology，sports medicine and other scientific research and teaching fields. The requirement of laboratory rabbit is followed after the rats，mice，hamsters and guinea pigs. It is an irreplaceable experimental material and model. Research on breeding and application of SPF laboratory rabbit is rapid development in developed countries. With the development of China's life sciences and medical research，and for the request of the new “Chinese Pharmacopoeia” and “China Requirement Biological Products”，on the quality of laboratory rabbit，it was gradually moves closer to the Clean level and SPF level. This paper is an overview on the progress of the work for SPF rabbit breeding and biological characteristics in China.

Objective To observing and analyze the microstructures and ultrastructures of the liver in zebrafish. Methods The tissue samples were observed by using light and electron microscopy.Results There was no typical portal area within the parenchyma, bile ducts and venules were randomly distributed within the parenchyma. The polygonal hcpatocytes are arranged in twisting, branching and anastomosing cords usually two cells thick .There was a single big and spherical nucleus in the hepatocyte,and the nucleoli displayed a separation into granulose component, fibrillar centers and dense fibrillar component. The cytoplasm are dominated by numerous stacks of non-fenestrated lamellae of rough endoplasmic reticulum (RER) of considerable length arranged in close parallel array and smooth endo-plasmic reticulum was rarely observed. The number of mitochondria is of considerable, and myelinbody was found in mitochondria. When the cytoplasm was rich in mitochondria, RER, and ribosome and the number of nucleopore was massive, glycogen was found in small concentrations, and a few lysosome may be observed. When glycogen was found in large concentrations, the number of nucleopore was few, so the cytoplasmic organoids were. These suggested that the consumption of glycogen ensured normal metabolism of nucleic acids and proteins, and mitochondria provided energy in the process of protein synthesis. The biliary system is arranged in arborization. Bile canaliculus includeded intracellular and intercellular bile canaliculus，the intracellular bile canaliculus had lots of long microvilli, the intercel-lular bile canaliculus had relatively shorter ones. Erythrocytes, lymphocytes，fat-storing cells and endot-helial cells were also described. A comparison between zebrafish liver and that of other teleosts was made. Conclusions The way of hepatocytes arranged in zebrafish was different from other teleostei and was not exactly conformable to previous accounts, this distinction was relevant to the animal species and research methods. The ultrastructure of hepatocytes proved its active synthesis and metabolic function.

Objective To found efficient procedure of inducing estrus in the bitch using exogenous gonadotropic hormones. Method Three groups of Beagle bitch, including anestrum, young of nonestrus and sterile aged bitches, were studied by combination of pregnant mare serum gonadotrophin （PMSG） + human chorionic gonadotropin （hCG） with different dose and administration separately. Result PMSG + hCG procedure was effective in the groups of anestrus and young bitches of nonestrus but ineffective for the sterile aged bitches （68.8% 25.0%）. Conclusion The success rate of inducing estrus with low dosage and multiple administration is markedly higher than that of the bitches with one administration.

Objective To supply some basic data for extension and application of BNX mice through observation on generally biological properties and peculiarity of tumor growth and metastasis after tumor implantation. Methods By the method of periodically measuring the weight、analyzing breeding character, graphing growth curve、examining hematological and blood biochemical parameters,we explored biological characteristics of BNX mice. At the same time，we also established tumor animal models of human gastric tumor （MKN-45） and human melanoma （SCI-375） in BNX mice through orthotopic and subcutaneous tumor implantation. Results It showed that there was a statistically significant difference of body weight between male and female BNX mice within 4?30 weeks （ P＜0.05）. The number of WBC in peripheral blood haematology of BNX mice was only equal to twenty-five percent of that of normal mice,while no statistically significant differences in biochemical parameters was observed between BNX mice and normal mice. The metastatic rates of orthotopic implant models of human gastric tumor （MKN-45） and subcutaneous implant models of human melanoma （SCI-375） in BNX mice were much higher than in nude mice and SCID mice.Conclusions These results suggest that BNX mice are more suitable for the study of establishment of tumor metastatic models compared with nude mice and SCID mice.

Objective To monitor the heart rate、temperature、hemodynamics and electrocardio-gram of beagle dog by telemetry. Methods After two weeks of imbedding the sensor in abdomen muscle, the heart rate、temperature、hemodynamics and electrocardiogram were monitored continuously for 24 hours by Dataquest A.R.T. 2.3, and repeated on next week. Results In all of the monitor process, every index maintain the normal level, but the heart rate rise to the highest about 95.58±15.89 beat per minute at 10 ： 00 am, with the systolic pressure、mean arterial blood pressure and diastolic pressure were 152.37± 10.67 mmHg、109.37±5.90 mmHg and 87.73±5.01 mmHg respectively. No differences were found between the two detection( P＞0.05). Conclusions The cardiovascular cardiovascular and physiology Characteristics of Beagle dog could been monitored more exactly by telemetry, and the beagle dog was very excited on diet.

Objective To comparative analysis of blood biochemical indexes in WHBE rabbits, Japanese White rabbits and New Zealand ^White rabbits，and further reveal on blood biochemical characteristics of WHBE rabbits. Methods Fourty in each of WHBE rabbits, Japanese White rabbits and New Zealand White rabbits，half male and female，the blood was sampled from the central artery of ear for testing the blood biochemical indexes. Results (1) Gender factor has significant influences on serum Ca, P, CHOL，HDL-C，LDL-C，FMN indexes m WHBE rabbits ( P＜0.05,尸<0.01); (2) Compared with Japanese White rabbits and New Zealand rabbits, partly blood biochemical indices had significant differences between WHBE rabbit and Japanese White rabbits or between WHBE rabbit and New Zealand White rabbits，those maybe related with itself characteristics;(3)CHOL, HDL-C, LDL-C, UA, CK and CK-MB were obviously exist with differences between human being and WHBE rabbit, and the other biochemical indexes were similar to those of human being. Conclusion The WHBE rabbits may be used for research on partly change of biochemical indices and metabolism diseases in human.

Objective To determine the normal ranges of blood physiological and biochemical data, and to determine the body weight and the weight of organs in Cricetulus Migratorius and compare for variations of these data between the sex. Method The blood samples collected were tested for physiological values by using MEK-7222K Hematology Analyzer, biochemical values by using OLYMPUS AU400 auto-analyser. The body weight and the weight organs were determined and the organ coefficient were calculated. Result The sexual difference of 8 weeks Cricetulus Migratorius was noted in physiological values such as WBC、RBC、HGB、HCT and RDW( P＜0.05) other than MCV、MCH、 MCHC、PLT、PCT、MPV and PDW (p>0.05)，and also noted in biochemical values such as AST、 BUN、GLU and CREA( P＜0.05) other than ALT、ALB、ALP、TP、CA、P、CHO and TG (p>0.05). Sexual difference of 8 weeks Cricetulus Migratorius was noted in organ coefficient such as spleen、right kidney、right adrenal glands、lungs and heart ( P＜0.05)，and also noted in organs weight such as spleen ( P＜0.05). Conclusion The normal physiological, biochemical data and the organ coefficient in Cricetulus Migratorius are affected by a variety of factors. Some of the data are significantly different between the both genders.

Objective To compare the genetic backgrounds of C57BL/6J and 129/SvJ and the behavioral phenotypes with their hybrid (F1) mice. Methods C57BL/6J and 129/SvJ were cross mated and bred to obtain two F1 (129B6F1 and B6129F1). These F1 mice with C57BL/6J and 129/SvJ were divided into 8 groups of experimental mice according to different gender. Numbers of mice in each group were no less than 12. Behavioral studies such as the open field test, the tail suspension test, the morris water maze, the passive avoidance test, the hot plate were conducted to compare the behavioral performance of C57BL/6J, 129/SvJ and F1 from the paramters of anxiety, depression, learning and memory, and heat pain response respectively. Results Compared with 129/SvJ, F1 had significant difference in peripheral and marginal activities in the open field activities ( P<0.01). There was no significant difference in the behavior of F1 and parent mice in the tail suspension activities. Compared with C57BL/6J, the latency of finding the platform and entering the dark box of F1 were significantly different in the morris water maze and the passive avoidance activities ( P<0.05). Conclusion Different behavior phenotypes of F1 are influenced by different genetic backgrounds of their parents.

Objective To determine and comparative analysis of reticulocytes and its subpopulation in WHBE rabbits，Japanese White rabbits and New Zealand White rabbits. Methods Fourty in each of WHBE rabbits, Japanese White rabbits and New Zealand White rabbits, half male and female, were used. The anticoagulant blood samples from the central artery of ear, and then reticulocytes parameters indexes were determined by Bayer ADVIA 120 automatic blood analyzer. Results (1) Gender factor has significant influences on RDWr，HDWr，CHDWr，RDWm, CHDWm, RDWg, CHDWg indexes m WHBE rabbits ( P＜0.05， P＜0.01); (2) Reticulocytes parameters in WHBE rabbits had significant differences between Japanese White rabbits and New Zealand White rabbits, for example, Retie % was lower in WHBE rabbits than that of Japanese White rabbits and New Zealand White rabbits( P＜0.01); (3)RPI in WHBE rabbits was similar to that of human being, compared with human reference. Conclusion WHBE rabbit has its own reticulocytes and its subpopulation characteristics, and may be used as model animal for research on anemia disease etc. in human.

Objective To determine and compare the hematological indexes (blood biochemical and physiological indexes) and the percentage of lymphocyte subsets in immunodeficient mice, providing basic data for tumor and immunology research applications. Methods (1) A total of 4 immunodeficient mouse strains, BALB/cA-nude, SCID, NOD-SCID, and NPSG, were included. Twenty mice (6-week-old, half male and half female) were analyzed. Blood biochemical (25 items) and physiological indexes (30 items) were determined and compared with those of BALB/cA-nude mice of the same age. (2) Four strains of immunodeficient mice, 4 mice (6-week-old, half male and half female) were randomly selected and analyzed with flow cytometry. Their symphocyte subsets were compared with those of BALB/cA-nude mice of the same age. Results (1) The white blood cell (WBC) count, lymphocyte (LYMPH) count, lymphocyte percentage (LYMPH%), and neutrophil count of immunodeficient mice were lower than those of BALB/cA mice ( P<0.01). In contrast, the neutrophil percentage (NEUT%) and reticulocyte count were higher than those of BALB/cA mice ( P<0.05, P<0.01). Furthermore, the levels of WBC, LYMPH and LYMPH% of SCID, NOD-SCID, and NPSG mice were significantly lower than those of BALB/cA-nude mice, while NEUT% was higher than that of BALB/cA-nude mice ( P<0.05). (2) The blood glucose and triglyceride levels in NOD-SCID and NPSG mice were lower than those in BALB/cA mice ( P<0.01), while uric acid level was higher than that of BALB/cA mice ( P<0.05). (3) BALB/cA mice had no T cells and low activity of B cells and natural killer (NK) cells. SCID and NOD-SCID mice had no T cells and lower activity of B cells and NK cells than BALB/cA-nude mice. NPSG mice had no T, B, and NK cells. Conclusion The blood biochemical and physiological indexes and the percentage of blood lymphocyte subsets in BALB/cA-nude, SCID, NOD-SCID and NPSG mice are consistent with the characteristics of corresponding immunodeficient mouse strains.

Some parameters of hametology and serum biochemistry were detected in NZB、NZW and （NZB×NZW）F1 mice.The results showed that there were significant differences in platelet and white blood count between the sexes of the 3 strains，it was also observed in the activities of AKP、AST and ALT. The results suggested that the characteristics in hametology and serum biochemistry of the 3 strains may be related to their deficiency in autoimmunity.

In order to provide the morphological data for establishing human cerebral vascular diseases model using miniature swine, the cerebral arterial circle and basilar artery were studied by means of 14 vascular specimens of the 3-5 months old miniature swines. The results were as follows：① The composition of the cerebral arterial circle was similar to that of human and some other swine breeds, but it differed from human and some other swine breeds that the proximal segments of both right and left lateral posterior cerebral artery connected in the manner of obtuse angle in 8 of the 14 specimens. According to the classification of гиидчe, most （11/14，78.6%） of the cerebral arterial circles of the miniature swines were equi-valent to the primary type and the others, the transitional type.②After recieving the branches of the occipital artery, the vertebral artery formed the cerebral-spinal artery which entered into the vertebral canal. After recieving the branches on the opposite side the cerebral-spinal artery formed the cerebral-spinal circle. The circle gave rise to the basilar artery and spinal-ventral artery.③The course of the basilar artery was similar to the usual pattern found in domestic animals.The whole course was curved and only one curvature was found in most of the specimens.The calibre of it becomed narrower as passed anteriorly.

Objective To observe the changes of estrogen and progestogen during the menstrual cycle in normal female cynomolgus monkeys. Methods Twenty sexually mature female cynomolgus monkeys aged 4-6 years and weighed 3.4-8.4 kg were enrolled in this study. Their blood specimens were collected regularly every day for 31 ?51 days to determine the serum levels of estradiol (E2) and progesterone (P) by microparticle enzyme immunoassay. Besides，the changes of E2 and P during the menstrual period，follicular phase, ovulatory period and luteal phase were observed in 6 of these monkeys with distinct menstrual cycle. Results The serum levels of E2 and P changed along with the menstrual cycle. The peak values of E2 occurred during the ovulatory period as well as luteal phase with the highest value during the ovulatory period; the peak values of P occurred during the luteal phase. Conclusion The changes of estrogen and progestogen during the menstrual cycle in normal female cynomolgus monkeys are similar to those in women of childbearing age. Therefore, normal female cynomolgus monkeys may be taken as models to study the changes of estrogen and progestogen levels in various stages of menstrual cycle in women.

Orient Hamster, Microtus fortis, is a wild rodent inhabited around Dongting Lake, Hunan Province. It was the only one species of rodents which resisted Schistosoma japanica infestation. Our work reveals that this hamster can raising and reproduce in the laboratory circumstance and either the captive wild Orient Hamster or the laboratory raised ones do have some characters of anti-Schistosoma infestation phenomenon