Effect of B-chromosomes on the duration of mitotic cycle in pearl millet

Summary Effect of B-chromosomes on the duration of the mitotic cycle was studied by a colchicine shock method in the root-tip cells of pearl millet (Pennisetum typhoides). 3 B-chromosomes were found to have very little effect, whereas 5 B-chromosomes resulted in an increase of the duration by about 39%.This investigation was financed by the University Grants Commission, New Delhi.     

Chalone regulation of the epidermal cell cycle.

Purified epidermal G2 chalone does not inhibit DNA synthesis or influx of S-phase cells and is therefore cell cycle phase-specific, inhibiting only the flow of cells into M-phase.     

Hypergravity: Its effect on the estrous cycle of rats

Summary Hypergravity affects the estrous cycle of rats. It is prolonged by a force of 1.39G–1.65G, and shows irregularities between 1.02 and 1.19G. Rats centrifuged for 40 days and returned to normal gravity presented a normal estrous pattern.     

Key factors in mTOR regulation

Mammalian target of rapamycin (mTOR) is a protein serine/threonine kinase that controls a wide range of growth-related cellular processes. In the past several years, many factors have been identified that are involved in controlling mTOR activity. Those factors in turn are regulated by diverse signaling cascades responsive to changes in intracellular and environmental conditions. The molecular connections between mTOR and its regulators form a complex signaling network that governs cellular metabolism, growth and proliferation. In this review, we discuss some key factors in mTOR regulation and mechanisms by which these factors control mTOR activity.