Wyniki wyszukiwania - Biblioteka Nauki

1

Developmental potential of mammalian somatic cells

100%

Modlinski J. A. , Piliszek A. , Karasiewicz J.

Biotechnologia

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2003

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nr 1

9-22

EN

The analysis of the experiments on somatic cloning of mammals reveals that possibly there is a group of cells whose nuclei have greater developmental potential than those of other cells. The group comprises cells of a particular developmental lineage, namely those originating from embryonic mesenchyme and mesoderm. The group remains to be elucidated if somatic cells effectively used for cloning are terminally differentiated, not yet fully differentiated or if they are stem cells. Developmental potential of somatic cell nuclei is best revealed when they are quiescent (i.e. in G0 phase of the cell cycle) upon being introduced into enucleated oocytes. The main obstacle in revealing the potencies of nuclei are the difficulties in their reprogramming before starting embryonic transcription, probably consisting in improper and not fast enough erasing of epigentic modifications of the genome. Developmental plasticity of whole cells as opposed to their nuclei has been experimentally presented in a particular class of somatic cells, namely in stem cells. Stem cells renewing a tissue of their origin can undergo transdifferentiation, that is, in atypical conditions they can differentiate into cells of other tissue and in chimaeras with early embryos - even into many diferent types of cells.

2

Development of the studies on somatic cell cloning in goats

88%

Skrzyszowska M. , Samiec M.

Biotechnologia

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2006

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nr 1

133-150

EN

Domestic goat as a species with a relatively great biodiversity of dairy breeds, which possess high genetic merit and yield of milk production, can be a valuable tool for embryo gene engineering. This involves the generation of transgenic specients, providing with xenogeneic (human) recombinant proteins (i.e. biopharmaceuticals), not only by the standard zygote intrapronuclear microinjection of gene constructs, but above all with the use of somatic cell cloning technology.

3

The role of domestic pig in somatic cell cloning and transgenesis

88%

Skrzyszowska M. , Samiec M.

Biotechnologia

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2006

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nr 1

53-67

EN

A stimulus for development of the studies on pig somatic cell cloning, especially in recent years, was above all the possibility of its practical application for production of transgenic piglets using in vitro transfected nuclear donor cells and multiplication of genetically-engineered sows and boars generated so far, on the grounds of important implications for biomedicine, pharmacy and agriculture. However, effective pig somatic cell nuclear transfer, avoiding the sexual reproduction pathway, creates a possibility of providing numerous monogenetic and monosexual offspring derived not only from genetically-transformed individuals, but also from adult (postpubertal) animals of high genetic merit. Generation of cloned transgenic pigs for biomedical purposes to obtain recombinant xenogeneic proteins or organs suitable in xenotransplantology, or to create cell (gene) therapy foundations for a number of serious monogenic diseases that induce heritable (congenital) developmental anomalies, is perceived as a service to humanity.

4

Bayesian inference of genetic parameters for test-day milk yield, milk quality traits, and somatic cell score in Burlina cows

75%

Penasa M. , Cecchinato A. , Battagin M. , De_ M. M. , Pretto D. , Cassandro M.

Journal of Applied Genetics

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2010

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tom 51

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nr 4

489-495

EN

The aim of the study was to infer (co)variance components for daily milk yield, fat and protein contents, and somatic cell score (SCS) in Burlina cattle (a local breed in northeast Italy). Data consisted of 13 576 monthly test-day records of 666 cows (parities 1 to 8) collected in 10 herds between 1999 and 2009. Repeatability animal models were implemented using Bayesian methods. Flat priors were assumed for systematic effects of herd test date, days in milk, and parity, as well as for permanent environmental, genetic, and residual effects. On average, Burlina cows produced 17.0 kg of milk per day, with 3.66 and 3.33% of fat and protein, respectively, and 358 000 cells per mL of milk. Marginal posterior medians (highest posterior density of 95%) of heritability were 0.18 (0.09-0.28), 0.28 (0.21-0.36), 0.35 (0.25-0.49), and 0.05 (0.01-0.11) for milk yield, fat content, protein content, and SCS, respectively. Marginal posterior medians of genetic correlations between the traits were low and a 95% Bayesian confidence region included zero, with the exception of the genetic correlation between fat and protein contents. Despite the low number of animals in the population, results suggest that genetic variance for production and quality traits exists in Burlina cattle.

5

The use of new strategies in the cloning studies on somatic cell cloning in pigs

75%

Skrzyszowska M. , Samiec M.

Biotechnologia

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2006

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nr 1

68-81

EN

Somatic cell nuclear transfer (SCNT) technique in pigs remains relatively low (2% to 5% of produced piglets), that is why further efforts have to be made to optimize both a multi-step cloning procedure and to improve a structuro-functional quality of recipient oocytes and nuclear donor cells. Pre- and postimplantation developmental potential of porcine SCNT-derived embryos depends to a high degree on not only coordination of mitotic cycle stage with phenotype of nuclear donor cell, but also proper combination of the methods of maternal chromosome elimination (enucleation), oocyte reconstruction techniques, the systems of artificial activation of generated nuclear-cytoplasmic hybrids (clonal cybrids) and in vitro culture of reconstructed embryos. Generally, it can result in increasing the competences of both somatic nuclear and mitochondrial genome for epigenetic remodeling/reprogramming in developing cloned embryos.

6

The Bcl-2 family proteins and calcium signaling in mammalian embryos generated by somatic cell cloning

63%

Samiec M.

Biotechnologia

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2010

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nr 1

66-81

EN

The efficiency of somatic cell nuclear transfer (SCNT) technology in mammalian species remains unsatisfactory. One of the main causes of low developmental capability of pre- and peri-implanted somatic cell cloned embryos is the high occurrence of apoptotic cell death, which is prompted by incorrect calcium signaling. The latter is accompanied by upregulation of the members from the Bcl-2 protein family in the blastomeres of SCNT embryos derived from the reconstructed oocytes exposed to artificial activating factors that induce the phenomenon of Ca2+ ion excitotoxicity. Overexpression of antiapoptotic proteins from the Bcl-2 family plays a fundamental role in suppression of different pathways involving intracellular transduction of programmed cell death signal in the somatic cell cloned embryos. Enhancement of Bcl-2 synthesis in the cytoplasm as well as on the outer/cytoplasmic surface of cisterns and tubules of granular endoplasmic reticulum (ERg) and thereby increase in its concentration and activity in the membranes of ER and mitochondria prevents the redistribution of free calcium cations from ER to mitochondria. The purpose of this article is to provide an overview of the current knowledge on molecular aspects of controlling calcium intracellular homeostasis in mammalian SCNT embryos, in which apoptotic cell death was stimulated by an improper activation of reconstituted oocytes.