All entries for Friday 07 October 2005
October 07, 2005
just click, ok? and thank your lucky stars.
M xxx lololololololoolll1111!!!!!!!!!!11roflolol!!!11......
Writing about web page http://forums.warwick.ac.uk/wf/browse/thread.jsp?fid=1299&tid=37226
WARNING: this is Biochemistry related. You have permission to run away screaming from your monitor.
ok useful sites i found:
- Activin A Maintains Pluripotency of Human Embryonic Stem Cells in the Absence of Feeder Layers
- Maintenance of Pluripotency in Human Embryonic Stem Cells Is STAT3 Independent
- In Vitro Maintenance of Highly Purified, Transplantable Hematopoietic Stem Cells
- Control of hematopoietic differentiation: Lack of specificity in signaling by cytokine receptors
- cDNA cloning of FRIL, a lectin from Dolichos lablab, that preserves hematopoietic progenitors in suspension culture
- Preserving the genetic integrity of human embryonic stem
These sites should all refer to stem cell maintainance in vitro. maybe. havn't read them in full yet
A bit on maintaining stem cells.
When used in vitro for research, it is vital that the stem cells used retain their "stemness" or "pluripotency". Without the correct stimulation the cells quicky differentiate into somatic cells, losing their "repopulating capacity"(1). Firstly, the normal procedure for maintaining the culture of cells is as a suspension. The cells must be kept disaggregated; This can be done manually or by nonenzymatic "CDB"(cell dissociation buffer) or enzymatic "CT"(collagenase/trypsin) cell passaging(2). However the CT and CDB methods were found to promote the development of abnormal karyotypes in the cultured stem cells (such as trisomy - particularly of chr17 and 20)
The conclusions were that up to 15 passages with CDB/CT could be used and still mantain a high fidelity to the normal stem cell karyotype(2).
The "cell passaging" seems to refer to the replacement to the medium in which the cells are suspended. Does anyone have a more precise definition?
"hESC"(human embryonic stem cell) cultures are generally grown in conjunction with feeder cells. These cells seem to secrete soluble factors that maintain the stem cells in their undifferentiated state – however the particular factors in question remain unidentified. "mESC"(mouse embryonic stem cells)
1. cDNA cloning of FRIL, a lectin from Dolichos lablab, that preserves hematopoietic progenitors in suspension culture
2. Activin A Maintains Pluripotency of Human Embryonic Stem Cells in the Absence of Feeder Layers
Maintenance of Pluripotency in Human Embryonic Stem Cells Is STAT3 Independent
these are the speakers for the International symposium on Germ Cells, Epigenetics and Embryonic Stem Cells. I've included mention of where they seem to be focused mostly on one specific area. (The links are just google scholar links to any of their stem cell papers)
- George Daley (Boston, USA)
- Anne Ferguson-Smith (Cambridge, UK)
- Woo Suk Hwang (Seoul, Korea)
- Thomas Jenuwein (Vienna, Austria)
chromosome related features of SCs
- Minoru Ko (Bethesda, USA)
gene expression in SCs
- Ihor Lemischka (Princeton, USA)
- En Li (Cambridge, Massachusetts, USA)
methylation patterns in stem cells
- Anne McLaren (Cambridge, UK)
primordial germ cells
- Martin Pera (Melbourne, Australia)
- Jean-Paul Renard (Paris, France)
cloning and role of chromatin
- Pierre Savatier (Lyon, France)
growth factors and signalling
- Gerald Schatten (Pittsburgh, USA)
- Hans Schoeler (Muenster, Germany)
- Austin Smith (Edinburgh, UK)
factors for stem cell differentiation
- Azim Surani (Cambridge, UK)
- Jonathan Tilly (Boston, USA)
SCs and mammalian oocytes
- Xiangzhong Yang (Storrs, Connecticut, USA)
SCs and cloning bovine embryos
- Guang-Quan Zhao (Dallas, USA)
Oh and a kitten. But why kittens and stem cells?
Because I say so. I love that answer.
*sigh* i know how it feels…
EDIT: Biochemisty is damaging to your mental health. I just found a malformed gummibear in my hairibo and caught myself thinking "I wonder what genetic defect it has? Looks like the morphogen gradient-induced cell differentiation went wrong..." AAaaarrrgggh! development overload. :s