940 resultados para Genetic differentiation
Resumo:
The discovery by Watson and Crick of the structure of DNA is one of the great scientific discoveries. In the period since that discovery new areas of genetic research have opened up which hold out the hope of developing treatments or cures for many illnesses and diseases. Yet with these discoveries have also come an array of ethical and legal dilemmas about the use of genetic information and concerns about the potential for those with genetic diseases or conditions to be stigmatised and discriminated against. The discussion about the developments in genetic science has become increasingly, a debate about the use of genetic information within our society. Graeme Laurie’s book, Genetic Privacy: A Challenge to Medico-Legal Norms, guides the reader through the complexities of these debates by considering what we mean by privacy and asking whether our existing concepts are adequate to meet the challenges posed by the new genetics.
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We show, using the PDR1 element of pea, that dispersed repeated sequences of moderate copy number can be used simply and efficiently to generate markers linked to a trait of interest. Inspection of hybridization patterns of repeated sequences to DNA mixtures of pooled genotypes is a sensitive way of detecting such markers. The large number of bands in tracks of digests of these mixtures allows the simultaneous sampling of loci at many places in the genome, and the many unlinked loci serve as internal controls. It is also shown that intensity ratios calculated from these band differences can be used to give a rough estimate of linkage distance.
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A DNA sequence between two legumin genes in Pisum is a member of the copia-like class of retrotransposons and represents one member of a polymorphic and heterogeneous dispersed repeated sequence family in Pisum. This sequence can be exploited in genetic studies either by RFLP analysis where several markers can be scored together, or the segregation of individual elements can be followed after PCR amplification of specific members.
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We have compared physical and genetic maps of the region around the legJ gene in pea. In this vicinity there are four B-type legumin genes, arranged as two close pairs. The detection of a recombination event within this gene cluster allows the orientation of this group of genes within the surrounding linkage group to be determined. The relationship between physical and genetic distances in this region is discussed, as are the implications of this for relating physical and genetic maps elsewhere in the pea genome.
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Introduction Female sexual functioning is affected by a range of factors including motivation, psychological well-being, and relationship issues. In understanding female sexual dysfunction (FSD), there has been a tendency to privilege diagnostic and medical over relationship issues. Aim To investigate the association between women’s experience of intimacy in close relationships - operationalized in terms of attachment and degree of differentiation of self - and FSD. Methods Two hundred and thirty sexually active Australian women responded to an invitation to complete a set of validated scales to assess potential correlates of sexual functioning. Main Outcome Measures The Female Sexuality Function Index, the Experiences in Close Relationships Scale, the Differentiation of Self Inventory, as well as a set of study-specific questions were subject to hierarchical multiple regression analyses Results Relational variables of attachment avoidance and to a lesser degree, attachment anxiety were associated with FSD. Participants with lower levels of differentiation of self were more likely to report sexual difficulties. The inability to maintain a sense of self in the presence of intimate others was the strongest predictors of sexual problems. A history of sexual abuse in adulthood and higher levels of psychological distress were also associated with sexual difficulties. Conclusions The findings provide support for a relational understanding of female sexual functioning. Attachment avoidance, attachment anxiety, and degree of differentiation of self are shown to be associated with sexual difficulties. The findings support the need to focus on relational and psychological factors in women’s experience of sex.
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A cDNA encoding the chloroplast/mitochondrial form of glutathione reductase (GR:EC 1,6,4,2) from pea (Pisum sativum L.) was used to map a single GR locus, named GORI. In two domesticated genotypes of pea (cv, Birte and JI 399) it is likely that the GORI locus contains a single gene. However, in a semi-domesticated land race of pea sequences were detected but closely related sets of GR gene sequences were in JI 281 represent either a second intact gene or a partial or pseudogene copy. A GR gene was cloned from ev. Birte, sequenced and its structure analysed. No features of the transcription or structure of the gene suggested a mechanism for generating any more than one form of . From these data plus previously published biochemical evidence was suggested a second, distinct gene encoding for the cytosolic form of GR should be present in peas. The GORI-encoded GR mRNA can be detected in all main organs of the plant and no alternative spliced species was present which could perhaps account for the generation of multiple isoforms of GR. The mismatch between the number of charge-separable isoforms in pea and the proposed number suggests that different GR isoforms arise by some form of post-transnational modification.
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Eighteen breast cancer cell lines were examined for expression of markers of epithelial and fibroblastic differentiation: E-cadherin, desmoplakins, ZO- 1, vimentin, keratin and β1 and β4 integrins. The cell lines were distributed along a spectrum of differentiation from epithelial to fibroblastic phenotypes. The most well-differentiated, epithelioid cell lines contained proteins characteristic of desmosomal, adherens and tight junctions, were adherent to one another on plastic and in the basement membrane matrix Matrigel and were keratin-positive and vimentin-negative. These cell lines were all weakly invasive in an in vitro chemoinvasion assay. The most poorly-differentiated, fibroblastic cell lines were E-cadherin-, desmoplakin- and ZO-1-negative and formed branching structures in Matrigel. They were vimentin-positive, contained only low levels of keratins and were highly invasive in the in vitro chemoinvasion assay. Of all of the markers analyzed, vimentin expression correlated best with in vitro invasive ability and fibroblastic differentiation. In a cell line with unstable expression of vimentin, T47D(CO), the cells that were invasive were of the fibroblastic type. The differentiation markers described here may be useful for analysis of clinical specimens and could potentially provide a more precise measure of differentiation grade yielding more power for predicting prognosis.
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In the last decade we have come to understand that the growth of cancer cells in general and of breast cancer in particular depends, in many cases, upon growth factors that will bind to and activate their receptors. One of these growth factor receptors is the erbB-2 protein which plays an important role in the prognosis of breast cancer and is overexpressed in nearly 30% of human breast cancer patients. While evidence accumulates to support the relationship between erbB-2 overexpression and poor overall survival in breast cancer, understanding of the biological consequence(s) of erbB-2 overexpression remains elusive. Our recent discovery of the gp30 has allowed us to identify a number of related but distinct biological endpoints which appear responsive to signal transduction through the erbB-2 receptor. These endpoints of growth, invasiveness, and differentiation have clear implications for the emergence, maintenance and/or control of malignancy, and represent established endpoints in the assessment of malignant progression in breast cancer. We have shown that gp30 induces a biphasic growth effect on cells with erbB-2 over-expression. We have recently determined the protein sequence of gp30 and cloned its full length cDNA sequence. We have also cloned two additional forms to the ligand, that are believed to be different isoforms. We are currently expressing the different forms in order to determine their biological effects. To elucidate the cellular mechanisms underlying cell growth inhibition by gp30, we tested the effect of this ligand on cell growth and differentiation of the human breast cancer cells which overexpress erbB-2 and cells which express low levels of this protooncogene. High concentrations of ligand induced differentiation of cells overexpressing erbB-2, as measured by inhibition of cell growth, and increased synthesis of milk components, and modulation of E-cadherin and up- regulation of c-jun and c-fos. These findings indicate that ligand-induced growth inhibition in cells overexpressing erbB-2 is associated with an apparent induction of differentiation. The availability of gp30 derived synthetic peptides and its full cDNAs provides tools necessary to acquire a better understanding of the mechanism of action of the this ligands and the erbB-2 receptor in breast cancer.
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Due to increasing clinical demand for adipose tissue, a suitable scaffold for engineering adipose tissue constructs is needed. In this study, we have developed a three-dimensional (3-D) culture system using bone marrow-derived mesenchymal stem cells (BM-MSC) and a Pluronic F-127 hydrogel scaffold as a step towards the in vitro tissue engineering of fat. BM-MSC were dispersed into a Pluronic F-127 hydrogel with or without type I collagen added. The adipogenic differentiation of the BM-MSC was assessed by cellular morphology and further confirmed by Oil Red O staining. The BM-MSC differentiated into adipocytes in Pluronic F-127 in the presence of adipogenic stimuli over a period of 2 weeks, with some differentiation present even in absence of such stimuli. The addition of type I collagen to the Pluronic F-127 caused the BM-MSC to aggregate into clumps, thereby generating an uneven adipogenic response, which was not desirable.
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Many data have emerged in support of the concept that the promotion of a migratory phenotype in epithelial cells is the result of an EMT, which leads to the loss of differentiation and to the acquisition of several mesenchymal features. Such an event is likely to occur during the metastatic conversion enabling the metastatic cell to invade the connective tissue and disseminate. Even though it cannot be excluded that some cancer cells might constitutively express a metastatic phenotype, the EMT implicated in the tumor progression process would rather be transient, induced in certain cells of the primary tumor by different factors, and reversed when the cells settle down in secondary organs (as schematically represented in Figure 1). However, it is clear that the phenotype that would emerge from the EMT occurring during tumor progression would also be modulated by the genetic background of the cells and must be to some extent different than the ones observed in normal physiological processes, and must also vary from one tumor to another.
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SPARC (secreted protein acidic and rich in cysteine)/ osteonectin/BM-40 is a matricellular protein implicated in development, cell transformation and tumorigenesis. We have examined the role of SPARC in cell transformation induced chemically with 7,12-dimethylbenz[a]anthracene (DMBA) and 12- tetradecanoylphorbol-13-acetate (TPA) in embryonic fibroblasts and in the skin of mice. Embryonic fibroblasts from SPARCnull mice showed increases in cell proliferation, enhanced sensitivity to DMBA and a higher number of DMBA/TPA-induced transformation foci. The number of DMBA-DNA adducts was 9 times higher in SPARCnull fibroblasts and their stability was lower than wild-type fibroblasts, consistent with a reduction in excision repair cross-complementing 1 the nucleotide excision repair enzyme in these cells. The SPARCnull mice showed an increase in both the speed and number of papillomas forming after topical administration of DMBA/TPA to the skin. These papillomas showed reduced growth and reduced progression to a more malignant phenotype, indicating that the effect of SPARC on tumorigenesis depends upon the transformation stage and/or tissue context. These data reinforce a growing number of observations in which SPARC has shown opposite effects on different tumor types/stages.
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It is accepted that the accelerated differentiation of tissue cells on bioactive materials is of great importance to regenerate the lost tissues. It was previously reported that lithium (Li) ions could enhance the in vitro proliferation and differentiation of retinoblastoma cells and endometrium epithelia by activating the Wnt canonical signalling pathway. It is interesting to incorporate Li ions into bioactive ceramics, such as β-tricalcium phosphate (Li-β-TCP), in order to stimulate both osteogenic and cementogenic differentiation of different stem cells for the regeneration of bone/periodontal tissues. Therefore, the aim of this study was to investigate the interactions of human periodontal ligament cells (hPDLCs) and human bone marrow stromal cells (hBMSCs) with Li-β-TCP bioceramic bulks and their ionic extracts, and further explore the osteogenic and cementogenic stimulation of Li-β-TCP bioceramics and the possible molecular mechanisms. The results showed that Li-β-TCP bioceramic disks supported the cell attachment and proliferation, and significantly enhanced bone/cementum-related gene expression, Wnt canonical signalling pathway activation for both hPDLCs and hBMSCs, compared to conventional β-TCP bioceramic disks without Li. The release of Li from Li-β-TCP powders could significantly promote the bone/cementum-related gene expression for both hPDLCs and hBMSCs compared to pure β-TCP extracts without Li release. Our results suggest that the combination of Li with β-TCP bioceramics may be a promising method to enhance bone/cementum regeneration as Li-β-TCP possesses excellent in vitro osteogenic and cementogenic stimulation properties by inducing bone/cementum-related gene expression in both hPDLCs and hBMSCs.
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Cardiovascular disease (CVD) affects millions of people worldwide and is influenced by numerous factors, including lifestyle and genetics. Expression quantitative trait loci (eQTLs) influence gene expression and are good candidates for CVD risk. Founder-effect pedigrees can provide additional power to map genes associated with disease risk. Therefore, we identified eQTLs in the genetic isolate of Norfolk Island (NI) and tested for associations between these and CVD risk factors. We measured genome-wide transcript levels of blood lymphocytes in 330 individuals and used pedigree-based heritability analysis to identify heritable transcripts. eQTLs were identified by genome-wide association testing of these transcripts. Testing for association between CVD risk factors (i.e., blood lipids, blood pressure, and body fat indices) and eQTLs revealed 1,712 heritable transcripts (p < 0.05) with heritability values ranging from 0.18 to 0.84. From these, we identified 200 cis-acting and 70 trans-acting eQTLs (p < 1.84 × 10(-7)) An eQTL-centric analysis of CVD risk traits revealed multiple associations, including 12 previously associated with CVD-related traits. Trait versus eQTL regression modeling identified four CVD risk candidates (NAAA, PAPSS1, NME1, and PRDX1), all of which have known biological roles in disease. In addition, we implicated several genes previously associated with CVD risk traits, including MTHFR and FN3KRP. We have successfully identified a panel of eQTLs in the NI pedigree and used this to implicate several genes in CVD risk. Future studies are required for further assessing the functional importance of these eQTLs and whether the findings here also relate to outbred populations.
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An essential step for therapeutic and research applications of stem cells is their ability to differentiate into specific cell types. Neuronal cells are of great interest for medical treatment of neurodegenerative diseases and traumatic injuries of central nervous system (CNS), but efforts to produce these cells have been met with only modest success. In an attempt of finding new approaches, atmospheric-pressure room-temperature microplasma jets (MPJs) are shown to effectively direct in vitro differentiation of neural stem cells (NSCs) predominantly into neuronal lineage. Murine neural stem cells (C17.2-NSCs) treated with MPJs exhibit rapid proliferation and differentiation with longer neurites and cell bodies eventually forming neuronal networks. MPJs regulate ~. 75% of NSCs to differentiate into neurons, which is a higher efficiency compared to common protein- and growth factors-based differentiation. NSCs exposure to quantized and transient (~. 150. ns) micro-plasma bullets up-regulates expression of different cell lineage markers as β-Tubulin III (for neurons) and O4 (for oligodendrocytes), while the expression of GFAP (for astrocytes) remains unchanged, as evidenced by quantitative PCR, immunofluorescence microscopy and Western Blot assay. It is shown that the plasma-increased nitric oxide (NO) production is a factor in the fate choice and differentiation of NSCs followed by axonal growth. The differentiated NSC cells matured and produced mostly cholinergic and motor neuronal progeny. It is also demonstrated that exposure of primary rat NSCs to the microplasma leads to quite similar differentiation effects. This suggests that the observed effect may potentially be generic and applicable to other types of neural progenitor cells. The application of this new in vitro strategy to selectively differentiate NSCs into neurons represents a step towards reproducible and efficient production of the desired NSC derivatives. © 2013.