20 research outputs found
A corresponding states approach to Small-Angle-Scattering for polydisperse ionic colloidal fluids
Approximate scattering functions for polydisperse ionic colloidal fluids are
obtained by a corresponding states approach. This assumes that all pair
correlation functions of a polydisperse fluid are
conformal to those of an appropriate monodisperse binary fluid (reference
system) and can be generated from them by scaling transformations. The
correspondence law extends to ionic fluids a {\it scaling approximation} (SA)
successfully proposed for nonionic colloids in a recent paper. For the
primitive model of charged hard spheres in a continuum solvent, the partial
structure factors of the monodisperse binary reference system are evaluated by
solving the Orstein-Zernike (OZ) integral equations coupled with an approximate
closure. The SA is first tested within the mean spherical approximation (MSA)
closure, which allows analytical solutions. The results are found in good
overall agreement with exact MSA predictions up to relevant polidispersity. The
SA is shown to be an improvement over the ``decoupling approximation'' extended
to the ionic case. The simplicity of the SA scheme allows its application also
when the OZ equations can be solved only numerically. An example is then given
by using the hypernetted chain (HNC) closure. Shortcomings of the SA approach,
its possible use in the analysis of experimental scattering data and other
related points are also briefly addressed.Comment: 29 pages, 7 postscript figures (included), Latex 3.0, uses aps.sty,
to appear in Phys. Rev. E (1999
Scientific, sustainability and regulatory challenges of cultured meat
Producing meat without the drawbacks of conventional animal agriculture would greatly contribute to future food and nutrition security. This Review Article covers biological, technological, regulatory and consumer acceptance challenges in this developing field of biotechnology. Cellular agriculture is an emerging branch of biotechnology that aims to address issues associated with the environmental impact, animal welfare and sustainability challenges of conventional animal farming for meat production. Cultured meat can be produced by applying current cell culture practices and biomanufacturing methods and utilizing mammalian cell lines and cell and gene therapy products to generate tissue or nutritional proteins for human consumption. However, significant improvements and modifications are needed for the process to be cost efficient and robust enough to be brought to production at scale for food supply. Here, we review the scientific and social challenges in transforming cultured meat into a viable commercial option, covering aspects from cell selection and medium optimization to biomaterials, tissue engineering, regulation and consumer acceptance
JARID2 is a direct target of the PAX3-FOXO1 fusion protein and inhibits myogenic differentiation of rhabdomyosarcoma cells
Rhabdomyosarcomas (RMS) are the most frequent soft-tissue sarcoma in children and
characteristically show features of developing skeletal muscle. The alveolar subtype is frequently
associated with a PAX3-FOXO1 fusion protein that is known to contribute to the undifferentiated
myogenic phenotype of RMS cells. Histone methylation of lysine residues controls developmental
processes in both normal and malignant cell contexts. Here we show that JARID2, that encodes a
protein known to recruit various complexes with histone methylating activity to their target genes,
is significantly overexpressed in RMS with PAX3-FOXO1 compared to fusion gene negative RMS
(t test p<0.0001). Multivariate analyses showed higher JARID2 levels are also associated with
metastases at diagnosis, independent of fusion gene status and RMS subtype (n= 120; p=0.039).
JARID2 levels were altered by silencing or over-expressing PAX3-FOXO1 in RMS cell lines with
and without the fusion gene, respectively. Consistent with this, we demonstrated that JARID2 is a
direct transcriptional target of the PAX3-FOXO1 fusion protein. Silencing JARID2 resulted in
reduced cell proliferation coupled with myogenic differentiation including increased expression of
MYOGENIN (MYOG) and MYOSIN LIGHT CHAIN (MYL1) in RMS cell lines representative of
both the alveolar and embryonal subtypes. Induced myogenic differentiation was associated with a
decrease in JARID2 levels and this phenotype could be rescued by overexpressing JARID2.
Furthermore, we that showed JARID2 binds to and alters the methylation status of histone H3
lysine 27 in the promoter regions of MYOG and MYL1 and that the interaction of JARID2 at these
promoters is dependent upon EED, a core component of the Polycomb Repressive Complex 2
(PRC2). Therefore JARID2 is a downstream effector of PAX3-FOXO1 that maintains an undifferentiated myogenic phenotype that is characteristic of RMS. JARID2 and other components of PRC2 may represent novel therapeutic targets for treating RMS patients