Tag Archives: placenta

Easy come, easy grow

Sperm cell release can be triggered by tightening the grip around the delivery organ, according to a team of nano and microsystems engineers and plant biologists at the University of Montreal and Concordia University. Concordia’s nanobiotech team devised a microchip that enabled the University of Montreal biologists to observe what happened when pollen tubes – the sperm delivery tools used by plants – tried to negotiate a microscopic obstacle course. The pollen tubes were exposed to a series of narrow, elastic openings resulting in a variety of cellular responses. When the opening was too narrow or tight, pollen tube growth stalled. However, the elongating tubes successfully penetrated slightly larger openings. Curiously, the pollen tubes burst and released the sperm cells when passing openings of a particular size relative to the pollen tube width. (more…)

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Seed Size is Controlled by Maternally Produced Small Rnas, Scientists Find

AUSTIN, Texas — Seed size is controlled by small RNA molecules inherited from a plant’s mother, a discovery from scientists at The University of Texas at Austin that has implications for agriculture and understanding plant evolution.

“Crop seeds provide nearly 70 to 80 percent of calories and 60 to 70 percent of all proteins consumed by the human population,” said Z. Jeff Chen, the D.J. Sibley Centennial Professor in Plant Molecular Genetics at The University of Texas at Austin. “Seed production is obviously very important for agriculture and plant evolution.” (more…)

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UCLA Scientists ID Cell, Signaling Pathway That Regulate Blood Stem Cells in Placenta

UCLA stem-cell researchers have identified a certain type of cell and a signaling pathway in the placental niche that play a key role in stopping blood stem cells from differentiating into mature blood cells in the placenta. Preventing this premature differentiation is critical to ensuring a proper blood supply for an individual’s lifetime.

The placental niche is considered a stem cell “safe zone,” which supports the creation and expansion of blood stem cells without promoting their differentiation into mature cells. This allows for the establishment of a pool of precursor cells that will later provide blood cells for fetal and post-natal life, said the study’s senior author, Dr. Hanna Mikkola, an associate professor of molecular cell and developmental biology at UCLA and a researcher at UCLA’s Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research. (more…)

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