Asunto(s)
Fusión Celular/métodos , Células Madre Embrionarias/fisiología , Fibroblastos/fisiología , Células Híbridas/fisiología , Animales , Técnicas de Cultivo de Célula , Mapeo Cromosómico , Cruzamientos Genéticos , Diploidia , Células Madre Embrionarias/citología , Fibroblastos/citología , Heterocigoto , Células Híbridas/citología , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos , Fenotipo , PoliploidíaRESUMEN
Ten primary clones of hybrid cells were produced by the fusion of diploid embryonic stem (ES) cells, viz., line E14Tg2aSc4TP6.3 marked by green fluorescent protein (GFP), with diploid embryonic or adult fibroblasts derived from DD/c mice. All the hybrid clones had many characteristics similar to those of ES cells and were positive for GFP. Five hybrid clones having ploidy close to tetraploidy (over 80% of cells had 76-80 chromosomes) were chosen for the generation of chimeras via injection into C57BL blastocysts. These hybrid clones also contained microsatellites marking all ES cell and fibroblast chromosomes judging from microsatellite analysis. Twenty chimeric embryos at 11-13 days post-conception were obtained after injection of hybrid cells derived from two of three clones. Many embryos showed a high content of GFP-positive descendents of the tested hybrid cells. Twenty one adult chimeras were generated by the injection of hybrid cells derived from three clones. The contribution of GFP-labeled hybrid cells was significant and comparable with that of diploid E14Tg2aSc4TP6.3 cells. Cytogenetic and microsatellite analyses of cell cultures derived from chimeric embryos or adults indicated that the initial karyotype of the tested hybrid cells remained stable during the development of the chimeras, i.e., the hybrid cells were mainly responsible for the generation of the chimeras. Thus, ES cell/fibroblast hybrid cells with near-tetraploid karyotype are able to generate chimeras at a high rate, and many adult chimeras contain a high percentage of descendants of the hybrid cells.
Asunto(s)
Quimera , Células Madre Embrionarias/citología , Fibroblastos/citología , Células Híbridas/citología , Poliploidía , Fosfatasa Alcalina/metabolismo , Animales , Blastocisto/citología , Blastocisto/metabolismo , Línea Celular , Cromosomas de los Mamíferos/metabolismo , Células Clonales/enzimología , Femenino , Técnica del Anticuerpo Fluorescente , Proteínas de Homeodominio/metabolismo , Cariotipificación , Lamina Tipo A/metabolismo , Masculino , Ratones , Repeticiones de Microsatélite/genética , Proteína Homeótica Nanog , Factor 3 de Transcripción de Unión a Octámeros/metabolismoRESUMEN
Chromosome segregation of the parental chromosomes was studied in 20 interspecific hybrid clones obtained by fusion of Mus musculus embryonic stem cells with Mus caroli splenocytes. FISH analysis with labeled species specific probes and microsatellite markers was used for identification of the parental chromosomes. Cytogenetic analysis has shown significant intra- and interclonal variability in chromosome numbers and ratios of the parental chromosomes in the hybrid cells: six clones contained all M. caroli chromosomes, nine clones showed moderate segregation of M. caroli chromosomes (from 1 to 7), and five clones showed extensive loss of M. caroli chromosomes (from 12 to complete loss of all M. caroli autosomes). Both methods demonstrated "cryptic" segregation of the somatic partner chromosomes. For instance, five clones with near-tetraploid chromosome sets contained only few M. caroli chromosomes (from 1 to 8). The data obtained suggest that the tetraploid chromosome set per se is not a sufficient criterion for conclusion on the absence of chromosome loss in the hybrid cells. Note that "cryptic" chromosome segregation occurred at a high frequency in the examined hybrid clones. Thus, "cryptic" segregation should be borne in mind for assessing pluripotency and genome reprogramming of embryonic stem hybrid cells.
Asunto(s)
Segregación Cromosómica/genética , Cromosomas de los Mamíferos/genética , Células Híbridas/ultraestructura , Ploidias , Células Madre/ultraestructura , Animales , Segregación Cromosómica/fisiología , Cromosomas de los Mamíferos/fisiología , Embrión de Mamíferos/citología , Células Híbridas/fisiología , Cariotipificación , Ratones , Células Madre/fisiologíaRESUMEN
In 4 S. marcescens polyresistant strains isolated from patients conjugative plasmids transferred to Escherichia coli have been detected. Two of these strains carry each one plasmid which codes resistance to 10 different antibiotics, including aminoglycosides which rarely occur in our country, and belongs to group IncC. The third strain is the host of 2 plasmids. One of them is similar to the above-mentioned 2 plasmids with respect to the incompatibility group and a set of markers, but additionally codes resistance to cephalosporins; the second plasmid has been determined as belonging to group IncM, unstable and capable of rendering the cells highly resistant only to aminoglycosides. And, finally, the fourth strain also carries 2 plasmids: one of them is unstable and belongs, supposedly, to group IncI alpha, and the second plasmid is stable and belongs to group IncM. The plasmid of group IncI alpha differs from all other plasmids of our Serratia by its capacity of rendering the cells highly resistant to chloramphenicol.
Asunto(s)
Factores R/efectos de los fármacos , Serratia marcescens/efectos de los fármacos , Antibacterianos/antagonistas & inhibidores , Conjugación Genética , Farmacorresistencia Microbiana , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Humanos , Fenotipo , Serratia marcescens/genética , Serratia marcescens/aislamiento & purificaciónRESUMEN
A total of 5 new conjugative plasmids pLD can be transferred from one Ps. aeruginosa strain to other strains of this species, but not to E. coli. Only the markers of resistance to mercury can be transferred to E. coli by means of plasmids Inc P-1. The present work contains the data confirming that the mercury markers of 2 plasmids pLD 1017 and pLD 1051 behave similarly to transposons.
Asunto(s)
Escherichia coli/genética , Marcadores Genéticos , Mercurio/antagonistas & inhibidores , Plásmidos , Pseudomonas aeruginosa/genética , Conjugación Genética , Farmacorresistencia Microbiana , Transducción GenéticaRESUMEN
An analysis of a qualitative composition of wound microflora grounded on the findings of the clinico-bacteriological examination of 315 cases with various pyo-inflammatory processes is presented here, and specific features of the species composition of wound microflora depending upon the character of a pyo-inflammatory process are shown. The sensitivity of staphylococcuses isolated from the wounds, to 19 antibacterial preparations is analyzed and recommendations on the most rational and differentiated use of antibacterial drugs in various forms of a purulent process of staphylococcal eti-logy are suggested.