A genetic typing method for albino mutation in the Mongolian gerbil by PCR-RFLP analysis.

1. We established a PCR-RFLP analysis targeting R77H mutation in the Tyr gene as a more effective genotyping to identify carrier (C/c) with the albino allele and the agouti phenotypes. 2. Our breeding system, which targets the R77H site, is a useful cue for detecting C/c carriers with the agouti-phenotype and helps us to obtain albinos by mating agouti-phenotype carriers.

Effects of synthetic para-nonylphenol isomers administered chronically throughout pregnancy and lactation on reproductive system of mouse pups.

The aim of this study was to analyze the effects of synthetic para-nonylphenol isomers administered chronically throughout pregnancy and lactation on the reproductive system of mouse pups. The two synthetic isomers used in this study showed higher (3E22NP) or lower (44NP) estrogen receptor (ER) binding activity on in vitro yeast assay than a commercial NP (NPmix). Female mice were implanted with a tube filled with one of three NPs and estradiol-17 ß (E2) before mating. The tube was kept in the mice throughout pregnancy and lactation period, until their pups had weaned at 28 days of age (PND 28). The data indicated that in males, NPs decreased body weight in some dose groups on PND28 and increased weights of testes and epididymides. However, the rate of seminiferous tubules having elongate spermatids (steps 10-16) decreased significantly in NPs and E2 treated groups, except for the 44NP groups. In female mice, NPs and E2 increased weights of ovaries, uterus and vagina in the pups in some dose groups on PND 28. However, there were no differences in the day of vaginal opening and numbers of corpus lutea. The present study demonstrates that the effects of these two isomers of NP on the pup reproduction at PND 28 are not quite different, despite them showing different levels of ER binding activity using in vitro yeast assay.

Effects of estradiol-17beta and bisphenol A administered chronically to mice throughout pregnancy and lactation on the male pups' reproductive system.

AIM: To assess the effect of estradiol-17beta (E(2)) and bisphenol A (BPA) administered chronically by implanting a silicone tube throughout pregnancy and lactation on male pups' reproductive system in ICR mice. METHODS: Female mice were implanted with a tube filled with 10 ng, 500 ng, 1 microg, or 10 microg of E(2), or 100 microg or 5 mg of BPA, before mating. The tube was kept in the mice throughout pregnancy and lactation, until the pups had weaned at 4 weeks of age. During the period, E(2) was released from the tube at 120 pg or 6, 12 or 120 ng/day, and BPA at 1.2 or 60 microg/day. RESULTS: Most of the mice given 1 microg and 10 microg of E(2) did not maintain their pregnancy. However, the other groups showed high rates of birth, more than 70%. At age of 4 weeks, the male pups were killed. Body weight and reproductive organ weights (testes, epididymides and accessory reproductive glands) in the treated groups did not differ from the control values, whereas the percentage of seminiferous tubules in the testis with mature spermatids was significantly lower in the groups given 10 ng and 500 ng of E(2) and 5 mg of BPA than that in the control. CONCLUSION: Chronic exposure to E(2) and BPA might disrupt spermatogenesis in male pups.

Counting absolute number of lymphocytes in quail whole blood by flow cytometry.

In a previous study, we reported a new method for counting quail blood cells. After quail blood cells were stained with fluorescent lipophilic dye (DiOC6(3)), absolute counts of erythrocytes, granulocytes, and monocytes were obtained by means of flow cytometry (FC). The FC method has the potential for application to avian blood cells count; however, the method was unable to distinguish between lymphocytes and thrombocytes. In the present study, we improved the FC method to obtain separate counts of lymphocytes using DiOC5(3). After quail blood cells were stained with DiOC5(3), the cells were measured with FC. Each blood cell type was distinguished by means of their typical FL-1 (green fluorescence) and SSC (side scatter). Absolute numbers of erythrocytes, granulocytes, monocytes and lymphocytes in whole blood were obtained. The improved FC analysis worked equally well with chicken (Gallus gallus) and goose (Anser cygnoides) blood.

Conditioned medium from gerbil--mouse T cell heterohybridomas improved antibody secretion.

Mongolian gerbils (Meriones unguiculatus) are widely used as animal models for a variety of infectious diseases. However, immunological reagents such as cytokines have not been characterized. Two heterohybridomas, D9(E6)C2B3 and D9(E4), obtained by fusion of gerbil splenocytes with mouse myeloma cells (P3-X63-Ag8.653), expressed gerbil CD3G mRNA. These cells were suggested to be T cell heterohybridomas. They also expressed gerbil IL6 [D9(E6)C2B3] and TGFB [D9(E4) and D9(E6)C2B3] mRNAs. The addition of conditioned medium (CM) obtained from the culture of D9(E6)C2B3 significantly enhanced antibody secretion and expression of gerbil Cγ1 and Cε IGHC mRNAs in the B11D2(C2) heterohybridoma, which secretes gerbil IgG1. However, the addition of CM from both heterohybridomas did not improve in proliferation of B11D2(C2) cells. These results indicate that CM from D9(E6)C2B3 improved the culture of gerbil-mouse heterohybridomas, possibly by secreting gerbil IL6.

Production of antibodies to sheep red blood cells and Brucella abortus in Mongolian gerbils (Meriones unguiculatus).

The levels of total and 2-mercaptoethanol (2-ME)-resistant antibodies in male Mongolian gerbils (Meriones unguiculatus) to sheep red blood cells (SRBC) were higher than those in male C57BL/6 mice after the first and second immunizations. On the other hand, the total antibody level to Brucella abortus (BA) in gerbils was comparable to that in mice, whereas 2-ME-resistant antibody titers were lower after the first and second immunizations than in mice. After injection of 8 x 10(4) SRBC, male gerbils did not produce either total or 2-ME-resistant antibodies after the first immunization, but they produced total and 2-ME-resistant antibodies after the first to the fourth immunizations with different dilutions of BA, and both types of antibody titers significantly increased with the repeated immunizations. There were no sex differences in total and 2-ME-resistant antibody production to SRBC.

Use of genomic in situ hybridization to identify chromosomes in gerbil-mouse heterohybridomas.

Heterohybridomas, created to secrete monoclonal antibodies, are generally unstable over long-term culture because of chromosome elimination during culture. To evaluate the karyotype of heterohybridomas, we used simultaneous genomic in situ hybridization (GISH), which can distinguish unambiguously between parental genomes in allopolyploid species. Using GISH, we discriminated gerbil and mouse chromosomes in heterohybridomas with high sensitivity. The GISH technique will allow evaluation of the stability and crossability of heterohybridomas made from the fusion of mouse cells with those of related species.

Isotype analysis of gerbil-mouse heterohybridomas by RT-PCR.

We designed primer sets specific to the immunoglobulin (Ig) heavy-chain constant region (IGHC) genes in Mongolian gerbil (Meriones unguiculatus) to amplify five gerbil IGHC cDNA sequences, Cµ, Cγ1, Cγ2, Cε, and Cα. Five gerbil-mouse heterohybridomas B11D2(C2), B11E2(D5).M, B5-3, D5, and C11 respectively expressed Cγ1, Cµ, Cγ2, Cγ2, and Cγ1. In contrast, a commercial isotyping kit for mouse Igs identified Cγ1, Cµ, Cγ3, Cγ3, and Cγ1, respectively, misidentifying gerbil IgG2 as IgG3 by cross-reactivity with anti-mouse IgG3 polyclonal antibody. These primer sets will allow the accurate estimation of gerbil Ig classes and IgG subclasses. These results from three gerbil strains indicate that the primer sets can be used for isotype analysis of gerbil mAbs and for evaluation of humoral immunity.

Sequence determination of the heavy-chain constant region in four immunoglobulin classes of Mongolian gerbils (Meriones unguiculatus).

We determined partial cDNA sequences of four immunoglobulin (Ig) classes-IgM, IgG1, IgE, and IgA-of Mongolian gerbil (Meriones unguiculatus). Each deduced Ig heavy-chain constant (IGHC) region-Cµ, Cγ1, Cε, and Cα-is structurally similar to its counterparts in the mouse and rat, and phylogenetic analysis suggests that the gerbil Igs are evolutionarily close to their counterparts. In spite of the high sequence homology to the other rodent Cγ sequences, the gerbil Cγ1 sequence differs from our previously reported Cγ2. This result indicates that the gerbil has at least two IgG subclasses. These four gerbil IGHC cDNA sequences will be useful for determining gerbil Ig isotypes and examining the expression of gerbil Ig mRNAs in response to parasitic and bacterial infections.

Partial sequence of Mongolian gerbil (Meriones unguiculatus) immunoglobulin gamma heavy chain constant region.

We determined the sequence of the immunoglobulin gamma heavy-chain constant (IGHC) region of the Mongolian gerbil (Meriones unguiculatus). To isolate a part of the IGHC complementary DNA, we designed primers on the basis of highly conserved sequences in mouse, rat and hamster. The deduced IGHC is structurally similar to counterparts in other mammalian species and shows 84.6% identity to the IGHC of hamster IgG, 76.6% to rat IgG1, 83.3% to rat IgG2a, 78.1% to mouse IgG1, 81.8% to mouse IgG2a, 79.1% to mouse IgG2b and 79.2% to mouse IgG3 at the nucleotide level. The results suggest that gerbil IgG is closely related to hamster IgG and rat IgG2a.

Establishment of gerbil-mouse heterohybridoma secreting immunoglobulin of Mongolian gerbil (Meriones unguiculatus) establishment of gerbil-mouse heterohybridoma.

Hybridomas, generated by fusing myeloma cells with B lymphocytes, secrete monoclonal antibodies (mAbs) specific for an antigen. To establish hybridomas that secrete Mongolian gerbil (Meriones unguiculatus) mAbs, we immunized gerbils with keyhole limpet hemocyanin (KLH) and fused splenocytes from them with a non-secreting mouse myeloma cell line (P3-X63-Ag8.653). We obtained hybridomas that secreted immunoglobulin (Ig) against KLH. These hybridomas had more chromosomes than either parent and retained several gerbil chromosomes. Therefore, these cells were heterohybridomas with both gerbil and mouse chromosomes. They expressed gerbil Ig heavy-chain constant (IGHC) region mRNA, but not mouse gamma (γ) 1 IGHC. SDS-PAGE and Western blot analyses indicated that the cells secreted whole Ig molecules of gerbil origin. Moreover, the cells continued secreting Ig for several months.

Release of 4-nonylphenol from a silicone tube implanted in mice.

Silicone tubes are commonly used as a tool for long-term steroid treatment in animals. However, the release rates of steroids from these tubes have not yet been accurately determined. We measured the amounts of 4-nonylphenol (NP) remaining in tubes implanted in mice to obtain accurate release rates for original amounts of 20 or 1,000 microg NP in silicone tube implants. We achieved an accurate figure for the release rate from the tube, calculated using the total recovery from both the contents of the tube and the silicone matrix of the tube. The regression curve for the remaining amount of NP, as a percentage of the original amount (1,000 microg) was calculated as y (%) = 83.033 - 3.4722t + 0.0375t(2), where t is the number of days after implantation. The mean release rate over 56 days was 1.6% of the original amount per day.