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Somatic Nuclei (somatic + nucleus)

Distribution by Scientific Domains

Life Sciences	83%

Selected Abstracts

Sex chromatin and sex chromosome systems in nonditrysian Lepidoptera (Insecta)

JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 2 2000
V. A. Lukhtanov
Eleven representatives of the superorder Amphiesmenoptera (Trichoptera + Lepidoptera) were examined for sex chromatin status. Three species represent stenopsychoid, limnephiloid and leptoceroid branches of the Trichoptera; eight species belong to the primitive, so-called nonditrysian Lepidoptera and represent the infra-orders Zeugloptera, Dacnonypha, Exoporia, Incurvariina, Nepticulina and Tischeriina. The female-specific sex chromatin body was found in the interphase somatic nuclei of Tischeria ekebladella (Bjerkander 1795) (Lepidoptera, Tischeriina). The sex chromatin was absent in all investigated Trichoptera species as well as in all representatives of the nonditrysian Lepidoptera except Tischeria ekebladella. The sex chromosome mechanism of Limnephilus lunatus Curtis 1834 (Trichoptera, Limnephilidae) is Z/ZZ. The sex chromosome mechanism of Tischeria ekebladella (Lepidoptera, Tischeriina) is ZW/ZZ including the W chromosome as the largest element in the chromosome set. The data obtained support the hypothesis that the Z/ZZ sex chromosome system, the female heterogamety and the absence of the sex chromatin body in interphase nuclei are ancestral traits in the superorder Amphiesmenoptera. These ancestral characters are probably kept constant in all the Trichoptera and in the most primitive Lepidoptera. The W sex chromosome and the sex chromatin evolved later in the nonditrysian grade of the Lepidoptera. It is proposed that the sex chromatin is a synapomorphy of Tischeriina and Ditrysia. [source]

Changes in global histone acetylation pattern in somatic cell nuclei after their transfer into oocytes at different stages of maturation

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 3 2008
Helena Fulka
Abstract In our study, we have examined the pattern of global histone modification changes in somatic cell nuclei after their transfer into mouse oocytes at different stages of maturation or after their parthenogenetic activation. While germinal vesicle (GV) staged immature oocytes are strongly labeled with anti-acetylated histone H3 and H4 antibodies, the signal is absent in both metaphase I and metaphase II oocytes (MI, MII). In contrast, the oocytes of all maturation stages show a presence of trimethylated H3/K4 in their chromatin. When somatic cells were fused to intact or enucleated GV oocytes, both the GV and the somatic cell nucleus showed a very strong signal for all the antibodies used. On the other hand, when somatic cells nuclei that are AcH3 and AcH4 positive before fusion are introduced into either intact or enucleated MI or MII oocytes, their acetylation signal decreased rapidly and was totally absent after a prolonged culture. This was not the case when anti-trimethyl H3/K4 antibody was used. The somatic cell chromatin showed only a slight decrease in the intensity of labeling after its transfer into MI or MII oocytes. This decrease was, however, evident only after a prolonged culture. These results suggest not only a relatively higher stability of the methylation modification but also some difference between the oocyte and somatic chromatin. The ability to deacetylate the chromatin of transferred somatic nuclei disappears rapidly after the oocyte activation. Our results indicate that at least some reprogramming activity appears in the oocyte cytoplasm almost immediately after GV breakdown (GVBD), and that this activity rapidly disappears after the oocyte activation. Mol. Reprod. Dev. 75: 556,564, 2008. © 2007 Wiley-Liss, Inc. [source]

DNA hypomethylation reduces homologous pairing of inserted tandem repeat arrays in somatic nuclei of Arabidopsis thaliana

THE PLANT JOURNAL, Issue 4 2005
Koichi Watanabe
Summary Fluorescent chromatin tagging makes possible tracking of specific loci in vivo and in situ. Loci tagged by the lac operator (lacO)/GFP-LacI/Nuclear Localization Signal (NLS) system show rapid motility and constrained chromatin dynamics in somatic nuclei of a transgenic line, designated EL702C, in Arabidopsis thaliana. The tagged loci associated with each other significantly more often than expected at random, due to homologous pairing of the lacO tandem repeat arrays. Furthermore, these arrays associated significantly more often than average euchromatic regions with heterochromatic chromocenters (CCs). We show now that the inserted lacO array in this transgenic line became strongly methylated at CG sites in the T3 generation, which can be reversed upon transfer into the mutant backgrounds of decrease in DNA methylation 1 (ddm1) and methyltransferase 1 (met1). Concomitantly, the tagged loci showed lower association frequencies as compared with the transgenics in wild-type background, which is correlated with a significant decrease in allelic and ectopic pairing of the lacO repeat arrays as visualized by fluorescence in situ hybridization. In contrast, the preferential association of the lacO arrays with heterochromatin, locus mobility in somatic nuclei and transcription of neighboring transgenes were not altered by reduced DNA methylation in ddm1 and met1 backgrounds. Our results show that repeat arrays can activate hypermethylation of the inserted locus that correlates with high frequencies of homologous pairing in somatic cells. In contrast, the preferential association of these inserted arrays with CCs in plant cells occurs through another mechanism. [source]

Striated Perineal Muscles: Location of Autonomic, Sensory, and Somatic Neurons Projecting to the Male Pig Bulbospongiosus Muscle

THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 11 2009
Maddalena Botti
Abstract The location, number, and size of the neurons innervating the bulbospongiosus muscle (BSM) were studied in male pigs, by means of Fast Blue (FB) retrograde transport. After injection of FB into the left BSM, labeled neurons were found bilaterally in the L2-S4 sympathetic trunk ganglia (STGs), in the caudal mesenteric ganglia (CMGs), in the microganglia of the pelvic plexus (PGs), in a dorsolateral area with respect to the central canal of S1-S3 segments of the spinal cord (SC) and in the S1-S4 ipsilateral and S2-S3 contralateral spinal ganglia (SGs). The mean number of labeled FB cells was 3,122 ± 1,968 in STGs, 979 ± 667 in CMGs, 108 ± 104 in PGs, 89 ± 39 in SC and 77 ± 23 in SGs. The area of the multipolar neurons was 852 ± 22 ,m2 in the STGs, 878 ± 23 ,m2 in the CMGs and 922 ± 31 ,m2 in the PGs. The multipolar SC neurons had an area of 1,057 ± 38 ,m2, while pseudounipolar SG cells had dimensions of 2,281 ± 129 ,m2. Our research enables us to highlight two peculiarities regarding the innervation of the boar BSM: the very high number of labeled autonomic neurons and the particular localization of the motor somatic nucleus. Anat Rec, 2009. © 2009 Wiley-Liss, Inc. [source]

Cloning Adult Farm Animals: A Review of the Possibilities and Problems Associated with Somatic Cell Nuclear Transfer

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 2 2003
J. L. Edwards
In 1997, Wilmut et al. announced the birth of Dolly, the first ever clone of an adult animal. To date, adult sheep, goats, cattle, mice, pigs, cats and rabbits have been cloned using somatic cell nuclear transfer. The ultimate challenge of cloning procedures is to reprogram the somatic cell nucleus for development of the early embryo. The cell type of choice for reprogramming the somatic nucleus is an enucleated oocyte. Given that somatic cells are easily obtained from adult animals, cultured in the laboratory and then genetically modified, cloning procedures are ideal for introducing specific genetic modifications in farm animals. Genetic modification of farm animals provides a means of studying genes involved in a variety of biological systems and disease processes. Moreover, genetically modified farm animals have created a new form of ,pharming' whereby farm animals serve as bioreactors for production of pharmaceuticals or organ donors. A major limitation of cloning procedures is the extreme inefficiency for producing live offspring. Dolly was the only live offspring produced after 277 attempts. Similar inefficiencies for cloning adult animals of other species have been described by others. Many factors related to cloning procedures and culture environment contribute to the death of clones, both in the embryonic and fetal periods as well as during neonatal life. Extreme inefficiencies of this magnitude, along with the fact that death of the surrogate may occur, continue to raise great concerns with cloning humans. [source]