Category Archives: Stem Cells

Plants grow upward from a tip of undifferentiated tissue called the shoot apical meristem. As the tip extends, stem cells at the center of the meristem divide and increase in numbers. But the cells on the periphery differentiate to form plant organs, such as leaves and flowers. In between these two layers, a group of boundary cells go into a quiescent state and form a barrier that not only separates stem cells from differentiating cells, but eventually forms the borders that separate the plant's organs.

Because each plant's form and shape is determined by organ formation and organ boundary creation, elucidating the underlying mechanisms that govern these functions could help scientists design the architecture of crop plants to better capture light and ultimately produce more crop yield with less input. New research from two teams led by Carnegie's Zhiyong Wang and Kathryn Barton focuses on the role of the crucial plant hormone brassinosteroid in the creation of plant-shoot architecture. Their work is published by Proceedings of the National Academy of Sciences during the week of December 3.

Like all organisms, plant growth and development is regulated by internally produced chemical signals, including hormones like brassinosteroid, which is found throughout the plant kingdom. The brassinosteroid signaling pathway is involved in regulating more than 1,000 plant genes. Mutant plants that are deficient in brassinosteroid that are grown in the dark show features of plants grown in the light. They also have defects at many phases of the plant life cycle, including reduced seed germination, dwarfism, and sterility.

The new study lead by Wang and Barton uncovered yet another role of brassinosteroid: the formation of boundaries between organs. Plants made hypersensitive to brassinosteroid displayed fused organs.

The team included lead author's Carnegie's Joshua Gendron and Jiang-Shu Liu, as well as Min Fan, Mingyi Bai, and Stephan Wenkel, from Carnegie, and Patricia Springer from the University of California Riverside.

Their investigations showed that activation of the brassinosteroid pathway represses a group of genes called the cup-shaped cotyledon, or CUC family, which is responsible for organ boundary formation. Using sophisticated techniques the team demonstrated that the protein in the brassinosteroid pathway that is responsible for binding to DNA and, in this case, for inhibiting CUC genes, is present at high levels in the meristem's undifferentiated stem cells and developing organ primordia, but very low in the boundary cells, suggesting that different levels of brassinosteroid activity contribute to the opposite growth behavior of these three types of cells.

"This work links the plant steroids to growth and development, organ boundary development, providing a link between the physiology of the plant and its architectural design," Wang and Barton said.

Journal reference: Proceedings of the National Academy of Sciences

Provided by Carnegie Institution for Science

Visit link:
Plant organ development breakthrough

Scientists at Cambridge University in the UK have found a way to make stem cells out of blood. An article in the university's Research News section says that the discovery increases "the hope that scientists could one day use stem cells made from patients own cells to treat cardiovascular disease." The research was in the journal Stem Cells: Translational Medicine.

The study outlines a method in which scientists can get the cells they need to make "induced pluripotent stem cells" from a routine blood sample. Until now, researchers have not been able to locate an appropriate cell in blood that could be turned into a stem cell. Instead, they have made, and often make cells from skin or other tissues, which can require a surgical procedure such as a biopsy.

Dr Amer Rana and his colleagues at the University of Cambridge grew patients blood in the lab and isolated what are known as "late outgrowth endothelial progenitor cells." The Research News article quotes Dr. Rana as saying

We are excited to have developed a practical and efficient method to create stem cells from a cell type found in blood. Tissue biopsies are undesirable particularly for children and the elderly whereas taking blood samples is routine for all patients.Researchers can freeze and store the blood cells, and then turn them into iPS cells at a later stage, rather than having to transform them as soon as they are sourced, as is the case for other cell types used previously. This will have tremendous practical value prolonging the use by date of patient samples.

Copyright 1997 - 2012 ThirdAge Media, LLC. All rights reserved.

See original here:
Stem Cells From Blood Sample

ScienceDaily (Dec. 3, 2012) Researchers have derived dopaminergic neurons from bone marrow stem cells in monkeys.

Parkinson's disease is a degenerative disorder of the central nervous system that is characterized by tremors, rigidity, slowness of movement, and difficulty walking. It is caused by loss of the neurons that produce the neurotransmitter dopamine (known as dopaminergic neurons). One of the primary goals in Parkinson's disease research is to develop a replacement for dopaminergic neurons.

In a new study, researchers led by Takuya Hayashi at the RIKEN Center for Molecular Imaging Science in Kobe, Japan, derived dopaminergic neurons from bone marrow stem cells in monkeys. The cells were retrieved during a standard bone marrow aspiration and then treated with growth factors that directed the stem cells to become dopaminergic neurons. The monkeys that donated the stem cells were treated with a chemical to induce Parkinson's disease and then received a transplant of the new dopaminergic neurons that had been derived from their own bone marrow stem cells. Monkeys that received the transplant showed significant improvement in motor defects.

This study demonstrates that dopaminergic neurons derived from adult bone marrow stem cells can be safely used to improve motor function in Parkinson's disease in monkeys.

The research is published in the Journal of Clinical Investigation.

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by Journal of Clinical Investigation.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Continued here:
Stem cell-derived dopaminergic neurons rescue motor defects in Parkinsonian monkeys

Stem cell discovery may revive damaged heart

(IANS) / 29 November 2012

A new discovery that tricks aging stem cells into rejuvenating mode could enable scientists to create youthful patches for damaged or diseased hearts and heal them, according to a Canadian study.

The breakthrough may enable scientists to create such life giving patches from a patients own stem cells - regardless of the patients age - while avoiding the threat of rejection, the study claims.

Stem cell therapies involving donated bone marrow stem cells run the risk of patient rejection in a portion of the population, argues Milica Radisic, associate professor of chemical engineering and applied chemistry at the University of Toronto, the Journal of the American College of Cardiology reports.

One method of avoiding such a risk has been to use cells derived from a patients own body. But until now, clinical trials of this kind of therapy using elderly patients own cells have not been a viable option, since aged cells tend not to function as well as cells from young patients, according to a Toronto statement.

If you want to treat these people with their own cells, how do you do this? asks Radisic. Its a problem that Radisic and co-researcher Ren-Ke Li think they might have an answer for: by creating the conditions for a fountain of youth reaction within a tissue culture. Li is a professor in the division of cardiovascular surgery.

Radisic and Li first create a micro-environment that allows heart tissue to grow, with stem cells donated from elderly patients at the Toronto General Hospital, where Li works.

Li and his team then tracked the molecular changes in the tissue patch cells. We saw certain aging factors turned off, states Li, citing the levels of two molecules in particular, p16 and (regucalcin) RGN, which effectively turned back the clock in the cells, returning them to robust and states.

Its very exciting research, says Radisic, who was named one of the top innovators under 35 by MIT in 2008 and winner of the 2012 Young Engineers Canada award.

Read the original post:
Stem cell discovery may revive damaged heart