The level of noradrenaline and serotonin in mice differing in behavior

Laboratory mice possessing Robertsonian translocation Rb (8, 17) 1IEM in their karyotype, reveal statistically significant ability for extrapolation of the direction of stimulus movement which disappears from animal's view. Inbred CBA mice with the same translocation are less capable, and CBA mice with normal karyotype are totally incapable of solving this task. Cortical noradrenaline levels in mice with Rb (8, 17) 1IEM were the lowest and brain stem levels the highest among the three groups investigated. Serotonin levels reveal no changes among these groups.     

The effect of the ACTH(4-10) fragment on certain forms of adaptive behavior in mice of various genetic groups

CBA/Lac/Sto mice, C57/BL/6J mice and random bred mice with robertsonian translocation of chromosomes 8 and 17 (T1IEM mice) were compared under normal conditions and after ACTH4-10 injections. The rate of food procuring learning in U-shaped maze and in radial 5-arm maze was studied, and the ability of mice to extrapolate the direction of stimulus movement. Peptide i. p. injections (40 mkg/kg) stimulated the learning in U-shaped maze in all genotypes. T1IEM mice demonstrated better radial arm maze performance than CBA. Peptide injections tended to improve it in the former and to impair in the latter genotype. T1IEM mice demonstrated the ability for extrapolation, while CBA mice revealed no such ability. ACTH4-10 injections improved problem solving only in T1IEM mice. Cases when animals "refused" to participate in the experiment, were significantly rare in groups of all genotypes under peptide treatment.     

A factor analysis of behavioral organization in mice]

Laboratory mice with Robertsonian translocation Rb(8,17)1Iem, mice of CBA substrain with the same translocation as well as CBA normal karyotype mice were investigated in several behavioural tests, their results being analysed by means of factor analysis. The genetic differences were revealed in the patterns of factor loadings, in particular in factors "feeding behaviour structure" and "weight loss". The behaviour of mice during logic problem solving (the ability to extrapolate the direction of food stimulus movement was tested) proved to be genotype-dependent in respect to connections with exploratory behaviour indices. Tendencies towards stereotypic or variable (plastic) behaviour patterns were revealed in CBA mice and mice with Rb(8,17)1Iem mice respectively.     

Food search by mice solving an extrapolation problem after suppression of smell by zinc sulfate

Anosmia induced by intranasal zinc administration to mice capable of solving an extrapolation problem (search for food which disappears from animal sight in definite direction), led to disturbance of normal food searching behaviour. In anosmic mice the percentage of task solutions (correct as well as incorrect) in which the trajectory was the shortest ("goal-directed"), was significantly lower than in controls. At the same time the percentages of correct "goal-directed" choices were equal in both groups. The main differences in the number of correct task solutions were among those trials in which non-goal-directed behaviour was delivered. Thus zinc induced anosmia provokes rather severe deteriorations of food searching behaviour. The investigated group of mice possessing Robertsonian translocation Rb(8, 17) 1 IEM, reveals no disturbance of extrapolation capacity during first 20 s after task presentation. This signifies that this capacity which in this group is higher than in other mice, is not determined by peculiarities of their olfaction.     

Synaptonemal complexes in mammals. I. The nature and mechanism of the formation of centric chromosome fusions (Robertsonian translocations)

The nature and mechanism of formation of chromosomes' centric fusion were studied in mammals using the spreading method and silver staining of pachytene chromosomes. The male mice carriers of Robertsonian translocations Rb (8, 17) 1IEM, animals with standard karyotypes and F1 hybrids were used. It was concluded that the centric fusions resulted from translocation events and do not differ from other simmetric structural rearrangements of the exchange types.     

Mitochondrial DNA Variation and the Evolution of Robertsonian Chromosomal Races of House Mice, Mus Domesticus

The house mouse, Mus domesticus, includes many distinct Robertsonian (Rb) chromosomal races with diploid numbers from 2n = 22 to 2n = 38. Although these races are highly differentiated karyotypically, they are otherwise indistinguishable from standard karyotype (i.e., 2n = 40) mice, and consequently their evolutionary histories are not well understood. We have examined mitochondrial DNA (mtDNA) sequence variation from the control region and the ND3 gene region among 56 M. domesticus from Western Europe, including 15 Rb populations and 13 standard karyotype populations, and two individuals of the sister species, Mus musculus. mtDNA exhibited an average sequence divergence of 0.84% within M. domesticus and 3.4% between M. domesticus and M. musculus. The transition/transversion bias for the regions sequenced is 5.7:1, and the overall rate of sequence evolution is approximately 10% divergence per million years. The amount of mtDNA variation was as great among different Rb races as among different populations of standard karyotype mice, suggesting that different Rb races do not derive from a single recent maternal lineage. Phylogenetic analysis of the mtDNA sequences resulted in a parsimony tree which contained six major clades. Each of these clades contained both Rb and standard karyotype mice, consistent with the hypothesis that Rb races have arisen independently multiple times. Discordance between phylogeny and geography was attributable to ancestral polymorphism as a consequence of the recent colonization of Western Europe by mice. Two major mtDNA lineages were geographically localized and contained both Rb and standard karyotype mice. The age of these lineages suggests that mice have moved into Europe only within the last 10,000 years and that Rb populations in different geographic regions arose during this time.     

Chromosome segregation in mice heterozygous for Robertsonian translocations. I. The effect of mutation in chromosome 17 on the disjunction of homologs in females

The effects of mutations on chromosome 17 upon the segregation of the metacentric and acrocentric homologues in the progeny of female mice heterozygous for Robertsonian translocations Rb(8.17) 1Iem and Rb(16.17) 7Bnr were studied. Genetic analysis indicated that the ratio of Rb to non-Rb (normal karyotype) progeny from mothers heterozygous for mutations tf, qk, t12 were not significantly different from 1:1 expected. Introduction of mutations T, Ki, Fu, t6 into the female genotype caused strong distortion of segregation and an increase in the proportion of progeny with normal karyotype (65-70%). From the data on embryonic mortality and cytogenetic observations, it is concluded that distortion of equal transmission arises before MII of meiosis. Consequently, preferential distribution of the metacentric chromosome into the polar body during the first meiotic division is relevant to the segregation distortion observed.     

Cytogenetic studies on wild house mice from Belgium

The present status of Robertsonian karyotype variation in populations of wild mice from Belgium is presented. Two fusions, Rb(4.12)1Nam and Rb(5.10)3Nam, were identified in the central plain of this flat country. Surrounding this region only mice with the usual 2n=40 karyotype occurred. From the distribution pattern some possible relationships to other Rb populations from Europe are discussed.     

Effect of volatile excretions induced with thymus-dependent antigen in female mice on the behavioural responses of males

It was found that thymus-dependent antigen sheep red blood cells in the optimal immunogenic dose (1 x 10(8) cells/mouse) induced in female mice of CBA and B6 strain secretion of attractive urinary volatile components (VCs), and in the supraoptimal dose (1 x 10(9) cells/mouse)--aversive VCs for intact males CBA strain. In a direct comparison of the properties ofVCs-immunized mice of CBA and B6, a modification of the effect of constitutive chemosignalling: disturbance of ability of females VCs to attract allogeneic males, was observed. The role of thymus-dependent antigen dose and sex of animals in the mechanism of generation of antigen-induced chemosignals is discussed.     

Differential effects of genes of the <Emphasis Type="Italic">Rb1</Emphasis> signalling pathway on osteosarcoma incidence and latency in alpha-particle irradiated mice

Osteosarcoma is the most frequent secondary malignancy following radiotherapy of patients with bilateral retinoblastoma. This suggests that the Rb1 tumour suppressor gene might confer genetic susceptibility towards radiation-induced osteosarcoma. To define the contribution of the Rb1 pathway in the multistep process of radiation carcinogenesis, we evaluated somatic allelic changes affecting the Rb1 gene itself as well as its upstream regulator p16 in murine osteosarcoma induced by (227)Th incorporation. To distinguish between the contribution of germline predisposition and the effect of a 2-hit allelic loss, two mouse models harbouring heterozygote germline Rb1 and p16 defects were tested for the incidence and latency of osteosarcoma following irradiation. We could show that all tumours arising in BALB/c×CBA/CA hybrid mice (wild-type for Rb1 and for p16) carried a somatic allelic loss of either the Rb1 gene (76.5%) or the p16 gene (59%). In none of the tumours, we found concordant retention of heterozygosity at both loci. Heterozygote knock-out mice for Rb1 exhibit a significant increase in the incidence of osteosarcoma following (227)Th incorporation (11/24 [corrected] in Rb1+/- vs. 2/18 in Rb1+/+, p=4×10(-5)), without affecting tumour latency. In contrast, heterozygote knock-out mice for p16 had no significant change in tumour incidence, but a pronounced reduction of latency (LT(50%) =355 days in p16+/- vs. 445 days in p16+/+, p=8×10(-3)). These data suggest that Rb1 germline defects influence early steps of radiation osteosarcomagenesis, whereas alterations in p16 mainly affect later stages of tumour promotion and growth.     

Phenomenon of parental resistance and its genetic regulation]

Lymphocytes of mice F1 (CBA X M523) and F1 (A X M523) transplanted to 1000 R irradiated CBA or A mice responded to the test antigens--SRBC or S. typhi Vi-antigen--by formation of 100--1000 times less antibody forming cells than in syngeneic recipients. An intermediate result is achieved when the lymphoid cells are transplanted to the irradiated M523 mice. Lymphocytes of mice F1 (A X CBA), F1 (CBA X C57Bl/6), or F1 (A X A.CA) developed a similar immune response in the irradiated syngeneic mice and in both parental lines. The ability of parental line M523 to respond to SRBC was the same as in the other lines studied when examined in situ or in adoptive transfer experiments. The stem hemopoietic cells of mice F1 (CBA X M523) develop in the spleen of CBA mice 2--2.5 times less hemopoietic colonies than in the spleen of syngeneic animals. A conclusion was drawn that mutation M523 in CBA mice inhibited the proliferation and differentiation of hemopoietic and lymphoid cells in the irradiated nonsyngeneic recipients.     

Genetic differences in lymphoid tissue reactivity during liver regeneration in mice of different lines]

The transfer of lymphocytes together with sheep erythrocytes from partially hepatectomized mice to syngenous lethally irradiated mice (CAB and C57BL) increased the number of antibody forming cells in the recipient's spleen. The lymphocytes of CBA mice acquired this ability much earlier after the operation (in 4 hours) than those of the C57BL mice (in 17 hours). After the transfer of lymphocytes in the semisyngenous system there was a decrease of antibody forming cells during subsequent recipient's immunization with sheep erythrocytes; this was the result of the graft versus host reaction. The latter reaction was less marked in the operated than in control mice. These changes also occurred earlier after the operation in the CBA than in C57BL mice.     

Suppressor cells as an agent of immune facilitation. II. Adoptive transfer of passively induced enhancement of allografted tumors

CBA mice injected intravenously with CBA anti-A/J spleen cell antiserum, and challenged subcutaneously 24 hr later with A/J-derived sarcoma 1 (Sa 1) develop progressive tumors. “Normal” CBA mice (i.e., injected with normal CBA serum or noninjected) reject the allograft within 20 days. Spleen cells taken from mice 20–35 days after the injection of antiserum and Sa 1 challenge can specifically transfer the ability to enhance tumor growth when injected into 200 rad irradiated recipients. Spleen cells taken 8 days after antiserum and Sa 1 challenge cannot transfer suppression. The induction of suppressor cells requires both antiserum treatment and Sa 1 challenge. Serum from suppressed mice, and from control mice that are rejecting their tumors, can also transfer suppression but only when taken 20–35 days after treatment. The suppressor cells function most effectively when transferred at the time of tumor challenge, however, they also inhibit the rejection of Sa 1 when mixed with nylon-wool purified sensitized T cells. Suppressor cells are both nylon-wool nonadherent and adherent. Further purification of the column-enriched cells using antiimmunoglobulin or anti-Thy 1.2, plus complement, suggests that both T and B cells can suppress. The mixed lymphocyte response (MLR) of spleen cells from mice challenged only with Sa 1 is inhibited 8 days after challenge. A secondary response is obtained at 20–27 days. In contrast, the MLR from antiserum and Sa 1-treated mice 8 days after challenge resembles a secondary response. By 20–27 days mice with progressive tumors have only a primary-like response. In the present experimental situation, mitomycin-treated spleen cells from antiserum and Sa 1-treated mice cannot significantly inhibit the MLR of normal cells.     

A new chromosomal race of the house mouse, Mus musculus domesticus, in the Vulcano Island-Aeolian Archipelago, Italy

In this paper we describe a new Robertsonian (Rb) race of the house mouse from Vulcano (Aeolian archipelago) through the identification of the metacentric chromosomes. We analysed fifteen mice. All the specimens were found to have the same karyotype 2n=26. This karyotype is characterized by Rb(1.2), Rb(3.9), Rb(4.13), Rb(5.14), Rb(8.12), Rb(10.16) and Rb(15.17). The differences between the race of Vulcano and the races in a neighbour island (Lipari) consist in the presence of Rb(10.16) and Rb(15.17) in the former and Rb(6.16) and Rb(10.15) in the latter. We discuss the possible hypotheses regarding the origin between these two races including the possible occurrence of a whole arm reciprocal translocation (WART) on the Vulcano island.     

Behavioural profiles of inbred mouse strains used as transgenic backgrounds. II: cognitive tests

One of the characteristic manifestations of several neurodegenerative diseases is the progressive decline in cognitive ability. In order to determine the suitability of six mouse strains (129S2/Sv, BALB/c, C3H/He, C57BL/6j, CBA/Ca and DBA/2) as transgenic background strains, we investigated the performance on a variety of tasks designed to identify subtle changes in cognition. In addition, a test of exploratory behaviour was used to probe the level of underlying anxiety in these mouse strains, as anxiety can be a confounding factor on behavioural performance generally. The C3H/He mice exhibited the least anxiogenic behavioural profile spending most time on the open arms of the maze, in contrast to the 129S2/Sv mice which spent the least amount of time in this location and were the quickest to move into a closed arm. The C3H/He mouse strain failed to acquire a visual discrimination task and failed to demonstrate learning on a water maze spatial learning task, in contrast to the CBA/Ca, DBA/2 and C57BL/6j strains which demonstrated a degree of learning in both tasks. No significant strain differences were identified on the object recognition task. These data, taken together, suggest that care must be taken when choosing cognitive tasks to be used with particular mouse strains and that task sensitivity must be considered as a critical element to research protocols with regard to these mouse strains.     

Effect of activation of serotonin 5-HT1A-receptors on the immune response in mice of the ASC strain with depressive-like behavior

Selective activation of serotonin 5-HT(1A)-receptors produced different effects on immunological reactivity in mice of ASC strain with genetic predisposition to depressive-like behavior, and parental CBA and AKR strains displaying no depressive reactions. Administration of 5-HT(1A)-receptors agonist 8-OH-DPAT at low dose (0.1 mg/kg) affecting upon presynaptic receptors resulted in immunostimulation in CBA mice and did not change the immune response level in mice of ASC strain. Activation of postsynaptic 5-HT(1A)-receptors with higher dose of 8-OH-DPAT (1.0 mg/kg) caused immunosuppression in CBA and AKR strains while under the same conditions the immune response of ASC mice was increased. Decrease the immune reactions in ASC mice was observed only after application of 8-OHDPAT at dose of 5 mg/kg. The changes of functional activity of pre- and postsynaptic 5-HT(1A)-receptors under a high predisposition to depressive-like behavior providing different effects of this receptor activation on immune function are discussed.     

Mapping quantitative trait loci affecting circadian photosensitivity in retinally degenerate mice

It is known that retinally degenerate C57BL/6J (rd/rd) mice have unattenuated circadian photosensitivity. However, the authors have previously found that CBA/J (rd/rd) mice that carry the same rd mutation have attenuated circadian photosensitivity compared to normal CBA/N (+/+) mice. In the present study, a quantitative trait locus (QTL) analysis using C57BL/6J (rd/rd) and CBA/J (rd/rd) mice was conducted in order to identify the genes affecting circadian photosensitivity of the rd mice. As a result, several putative QTLs onthree separate chromosomes (8, 12, 17) were detected, which indicates that circadian photosensitivity in rd mice is altered by multiple genes. Identification of these genes may provide new insights into the understanding of regulation of circadian photoentrainment and sleep-wake disorders.     

The pathogenic Th17 cell response to major schistosome egg antigen is sequentially dependent on IL-23 and IL-1β

CBA/J mice infected with the helminth Schistosoma mansoni develop severe CD4 T cell-mediated hepatic granulomatous inflammation against parasite eggs associated with a robust Th17 cell response. We investigated the requisites for Th17 cell development using novel CD4 T cells expressing a transgenic TCR specific for the major Sm-p40 egg Ag, which produce IL-17 when stimulated with live schistosome eggs. Neutralization of IL-23 or blockade of the IL-1 receptor, but not IL-6 neutralization, abrogated egg-induced IL-17 secretion by transgenic T cells, whereas exogenous IL-23 or IL-1β reconstituted their ability to produce IL-17 when stimulated by syngeneic IL-12p40-deficient dendritic cells. Kinetic analysis demonstrated that IL-17 production was initiated by IL-23 and amplified by IL-1β. Significantly, schistosome-infected IL-12p40-deficient or IL-1R antagonist-treated CBA/J mice developed markedly reduced hepatic immunopathology with a dampened egg Ag-specific IL-17 response. These results demonstrate that the IL-23-IL-1-IL-17 axis has a central role in the development of severe schistosome egg-induced immunopathology.     

The myeloid differentiation factor 88 (MyD88) is required for CD4+ T cell effector function in a murine model of inflammatory bowel disease

Abnormal T cell responses to commensal bacteria are involved in the pathogenesis of inflammatory bowel disease. MyD88 is an essential signal transducer for TLRs in response to the microflora. We hypothesized that TLR signaling via MyD88 was important for effector T cell responses in the intestine. TLR expression on murine T cells was examined by flow cytometry. CD4(+)CD45Rb(high) T cells and/or CD4(+)CD45Rb(low)CD25(+) regulatory T cells were isolated and adoptively transferred to RAG1(-/-) mice. Colitis was assessed by changes in body weight and histology score. Cytokine production was assessed by ELISA. In vitro proliferation of T cells was assessed by [(3)H]thymidine assay. In vivo proliferation of T cells was assessed by BrdU and CFSE labeling. CD4(+)CD45Rb(high) T cells expressed TLR2, TLR4, TLR9, and TLR3, and TLR ligands could act as costimulatory molecules. MyD88(-/-) CD4(+) T cells showed decreased proliferation compared with WT CD4(+) T cells both in vivo and in vitro. CD4(+)CD45Rb(high) T cells from MyD88(-/-) mice did not induce wasting disease when transferred into RAG1(-/-) recipients. Lamina propria CD4(+) T cell expression of IL-2 and IL-17 and colonic expression of IL-6 and IL-23 were significantly lower in mice receiving MyD88(-/-) cells than mice receiving WT cells. In vitro, MyD88(-/-) T cells were blunted in their ability to secrete IL-17 but not IFN-gamma. Absence of MyD88 in CD4(+)CD45Rb(high) cells results in defective T cell function, especially Th17 differentiation. These results suggest a role for TLR signaling by T cells in the development of inflammatory bowel disease.