Genetic rescue of lethal genotypes in the mouse

Deletions of gene sequences in chromosome 7 of the mouse are known to interfere with biochemical and cellular development differentiation with lethal effects in homozygotes. The presence of the corresponding wild-type alleles in Cattanach's translocation (chromosomes 7 to X) is able to “rescue” potentially lethal females if they are made heterozygous for the translocation-carrying X chromosome. This holds true for those chromosome 7 deletions with perinatally lethal effects, whereas “rescue” is not readily accomplished with the deletions that cause early embryonic lethality. Females homozygous for the relevant deletion sequences and heterozygous for the translocation-carrying X chromosome are mosaics of two cell types: those in which the wild-type alleles included in the translocated piece complement the depleted sequences, resulting in a normal cellular phenotype, and those with the ordinary X chromosome expressing the lethal phenotype. The developmental interactions between the two cell types and their role in the mechanisms responsible for survival of females homozygous for lethal deletions are discussed. The failure of “rescue” of embryonic lethals reflects as yet unknown temporal and functional aspects of X-inactivation early embryogenesis.     

Differences in the reactivity of 2 mouse genotypes to zoo-social signals in the partition test

The reaction was studied of male mice of CBA and C57BL/6J lines to zoosocial signals coming from another individual. "Partition" test was used, in which two males of one line were placed in a common cage divided into two sections by a transparent partition with holes; this partition divided the animals but allowed them to see and sniff each other. The number of approaches to partition, summary and average time of staying near it during one approach were recorded. Mice of both lines reacted to presence of unknown partner behind the partition by an increase of activity near the partition; in CBA mice all recorded parameters were greater than in C57BL/6J mice. A greater sensitivity is suggested of CBA animals to perception of pheromonal signals. "Partition" test may be used for estimation of mice reaction to zoosocial signals.     

Comparative characteristics of the diagnostic properties of staphylococcal allergens in an experiment

The diagnostic value of five staphylococcal allergens prepared from a single S. aureus strain by different methods and in different institutions has been tested on the experimental models of delayed, immediate and mixed (immediate and delayed) hypersensitivity in guinea pigs. The advantages of the allergens prepared in Kazan (USSR) for the detection of delayed hypersensitivity and the ultrasonicated allergen, as well as the allergen made in Czechoslovakia, for the detection of immediate hypersensitivity have been noted.     

Thie expression of an intraspecific aggressive reaction in the face of a stressor agent alters the immune response in rats.

The repercussion on the immune response of the expression of intraspecific aggressiveness in the face of a stressor agent was investigated in rats. Ninety-day-old animals were divided into three groups: the control group (only immunological measurements were performed), the foot-shock (FS) (animals individually receiving FS), and the intraspecific aggressive response (IAR) group (animals receiving FS and presenting IAR). For immunological measurements, blood samples were collected promptly at 7 and 15 days after FS or IAR. The FS reduced the total leukocyte amount presented. However, aggressiveness triggered not only reduction of the leukocytes, but also lymphocyte decrease and neutrophil increase. Moreover, an elevation in total leukocytes associated with an increase in the humoral immune response was also observed one week after IAR. In this study, the expression of intraspecific aggressiveness in the face of a stressor seemed to activate the immune system and to potentiate the antigen specific humoral response.     

Application of an allele-specific polymerase chain reaction to the direct determination of ABO blood group genotypes.

The allele-specific polymerase chain reaction (ASPCR) procedure has proven a powerful tool for the detection and analysis of known genetic polymorphisms. Here, we present a novel application of the ASPCR technique to determine the ABO genotypes of individuals without the need of family analysis. The method introduces a new strategy for primer design that permits the identification of the different ABO genotypes according to the molecular size of allele-specific amplification products. Four primer sets, each specific for a different set of ABO alleles, are mixed in one reaction and the amplification products are resolved on a polyacrylamide gel. Forty-one individuals belonging to various families, whose ABO phenotypes were previously determined serologically, were typed with this new variation of the ASPCR technique. A 100% correlation between the serology and the ASPCR data was found. The Mendelian segregation of ABO alleles was also demonstrated in families. The method is rapid, simple, reproducible, and specific. Potential applications include gene mapping, genetic disease diagnosis, HLA typing, paternity testing, and forensic science.     

不同决明基因型的耐铝特性

在铝浓度120 mg·L-1条件下,通过溶液培养试验,研究了40个决明品种(系)对铝毒的反应.比较了不同基因型各性状的相对耐性值及其与综合评价系数的相关性.结果表明:相对株高、相对根系干物质量、相对地上部干物质量和相对根系活力可作为决明耐铝毒基因型筛选的重要指标.40个品种(系)中,86134R2、2208、3170、316、2211、2232的耐铝毒能力较强,属于耐铝毒的决明基因型,而34721R1、92985、3184的耐铝毒能力较弱,属于铝敏感的决明基因型.     

The karyotypic variability of mouse embryonic fibroblasts of 2 genotypes during spontaneous neoplastic transformation

Karyological analysis of 6 lines with distinct tumorigenic properties of mouse strains C3H/He and C57BL/6 has been carried out using a differential staining of chromosomes. The number of normal copies of chromosomes varied in all the investigated cell lines. The more and the less stable chromosomes different from line to line. All the cell lines were characterized by decreased numbers of copies of normal chromosome 7; a decreased number of normal copies of chromosome 2 and 16 was detected in the course of the cell spontaneous neoplastic evolution. The decreased number of normal copies of chromosomes 8, 12 and X, and the increased number of normal copies of chromosome 10 were specific of the cell lines with intermediate tumorigenicity. The maximum tumorigenic cell lines differed from all other lines by increased numbers of copies of chromosomes 4 and 5, and by a decrease in copy number of chromosome 6. The data obtained are discussed in terms of the search of the regularity of karyotypic changes in the course of the cell neoplastic evolution.     

The reaction of wheat genotypes to Septoria tritici

Seedling leaves, flag leaves, culms and heads of wheat genotypes were evaluated under glasshouse and field conditions for reaction to Septoria tritici. Parameters used for resistance screening were the incubation and latent periods, disease and sporulation levels, and 1000 grain weight. Significant correlations were obtained between reactions of different plant organs and between field and glasshouse tests; significant interspecific and intraspecific differences occurred for all screening parameters. Triticum aestivum varieties showed a wide range of disease reaction ranging from the high resistance of Elite Lepeuple, Maris Dove, Maris Ensign, Chalk and Tommy to the high susceptibility of Rothwell Sprite, Sovereign, Cardinal, Maris Ranger and Maris Templar.     

Effect of genotype on the development of aggressive and submissive behavior in the mouse

Aggressive and submissive behaviour was studied in CBA/Lac and C57BL/6J strains of mice during long-term intermale interaction with syngenic partners. It was shown that the aggressiveness of aggressive C57BL/6J animals was more expressive than that of CBA/Lac' ones. The structure of submissive behaviour of this strains' encounters was also significantly different. Prolonged-defeat experience changed the character of submissive behaviour of C57BL/6J, but not of CBA/Lac' ones. Aggression of dominant animals considerably decreased in both strains. It is suggested that CBA/Lac and C57BL/6J mice had different mechanisms of suppression of intermale aggression.     

Diel variations in the aggressive behaviour of the mouse, Mus musculus

Experiments to determine the extent of diel variations in the aggressive behaviour of male ICR mice involved (1) independent observations of different mice at different times of the day and (2) multiple observations on individual mice at different times. It was found that wounding varied over the 24-hr period, the rhythm of wounding was shifted with shifts in the photoperiod, and the rhythm of aggression was correlated with the rhythm of activity. The two peaks of aggression corresponded with the change from light to dark and dark to light.     

Disruption of mouse CD46 causes an accelerated spontaneous acrosome reaction in sperm

Human membrane cofactor protein (MCP, CD46) is a ubiquitously expressed protein known to protect cells from complement attack. Interestingly, when we examined the expression of mouse CD46, which we recently cloned, the message was found only in testis and the protein was found on the inner acrosomal membrane of sperm. In order to elucidate the function of CD46, we produced mice carrying a null mutation in the CD46 gene by using homologous recombination. Despite the absence of CD46, the mice were healthy and both sexes were fertile. However, to our surprise, the fertilizing ability of males appeared to be facilitated by disruption of the CD46 gene, as the average number of pups born from CD46(-/-) males was significantly greater than that of wild-type males. It was also revealed that the incidence of the spontaneous acrosome reaction doubled in CD46(-/-) sperm compared to that in wild-type sperm. It was assumed that this increase caused the heightened fertilizing ability found in CD46(-/-) sperm. These data suggest that CD46 may have some role in regulating sperm acrosome reaction.     

Comparative analysis of sequence characteristics of imprinted genes in human, mouse, and cattle

Genomic imprinting is an epigenetic mechanism that results in monoallelic expression of genes depending on parent-of-origin of the allele. Although the conservation of genomic imprinting among mammalian species has been widely reported for many genes, there is accumulating evidence that some genes escape this conservation. Most known imprinted genes have been identified in the mouse and human, with few imprinted genes reported in cattle. Comparative analysis of genomic imprinting across mammalian species would provide a powerful tool for elucidating the mechanisms regulating the unique expression of imprinted genes. In this study we analyzed the imprinting of 22 genes in human, mouse, and cattle and found that in only 11 was imprinting conserved across the three species. In addition, we analyzed the occurrence of the sequence elements CpG islands, C + G content, tandem repeats, and retrotransposable elements in imprinted and in nonimprinted (control) cattle genes. We found that imprinted genes have a higher G + C content and more CpG islands and tandem repeats. Short interspersed nuclear elements (SINEs) were notably fewer in number in imprinted cattle genes compared to control genes, which is in agreement with previous reports for human and mouse imprinted regions. Long interspersed nuclear elements (LINEs) and long terminal repeats (LTRs) were found to be significantly underrepresented in imprinted genes compared to control genes, contrary to reports on human and mouse. Of considerable significance was the finding of highly conserved tandem repeats in nine of the genes imprinted in all three species. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.     

Epithelial cell death in the oil-induced decidual reaction of the pseudopregnant mouse: an ultrastructural study.

Arachis oil instilled into the uterus of sensitized mice was localized mesometrially or, more commonly, antimesometrially, suggesting that the uterus is polarized in its capacity to respond since implantation chambers only form antimesometrially. Epithelial breakdown occurred only within the 'implantation chabmer', but cell death took place more rapidly than in normal pregnancy and was complete at only 5 to 9 hr after the Pontamine Blue reaction. Between 19 and 43 hr after oil instillation, the antimesometrial epithelial cells lost contact with each other and initially were characterized by distended rough endoplasmic reticulum and Golgi body, lipid droplet accumulation and ribosome segregation. At a later stage of deterioration, epithelial cell contents were scattered into the uterine lumen where polymorphonuclear leucocytes and monocytes were also found, probably involved in ingesting the cellular debris. There was no evidence of increased size of lysosomal dense bodies or of the formation of autophagosomes in dying epithelial cells; suggesting that the mechanism of epithelial death in the oil-induced reaction is not identical to that of normal pregnancy.     

Selection of a highly aggressive myeloma cell line by an altered bone microenvironment in the C57BL/KaLwRij mouse

In multiple myeloma (MM), bone marrow microenvironment has an important role for the survival and growth of plasma cells. We previously showed that a high bone turnover, induced by ovariectomy, increased MM cells growth in the 5T2MM model. The present study characterized a new plasma cell line (5THL) which was isolated from 5T2MM mice previously ovariectomized. Cells were propagated unchanged in normal C57BL/KaLwRij mice during six generations. 5THL was compared to the original 5T2MM phenotype. Paraproteinemia was detected 6 weeks post injection in 5THL mice and after 8 weeks in 5T2MM mice. All 5THL mice developed a hind-limb paralysis after 10 weeks. 5T2MM mice were euthanized at 16 weeks, due to a more progressive development of the disease. In 5THL mice, osteolytic lesions were observed after 8 weeks and severe bone destruction was evidenced at 10 weeks. In 5T2MM mice, minimal lesions were observed only after 10 weeks. Like in 5T2MM mice, no extra osseous lesions were observed in 5THL mice. The 5THL MM model closely mimics human myeloma with higher and faster bone aggressiveness. This new aggressive cell line, with a preserved phenotype, was selected by an altered microenvironment due to an increased bone turnover.