20 research outputs found
Calcium ion currents mediating oocyte maturation events
During maturation, the last phase of oogenesis, the oocyte undergoes several changes which prepare it to be ovulated and fertilized. Immature oocytes are arrested in the first meiotic process prophase, that is morphologically identified by a germinal vesicle. The removal of the first meiotic block marks the initiation of maturation. Although a large number of molecules are involved in complex sequences of events, there is evidence that a calcium increase plays a pivotal role in meiosis re-initiation. It is well established that, during this process, calcium is released from the intracellular stores, whereas less is known on the role of external calcium entering the cell through the plasma membrane ion channels. This review is focused on the functional role of calcium currents during oocyte maturation in all the species, from invertebrates to mammals. The emerging role of specific L-type calcium channels will be discussed
Variability and trait‐specific accessions for grain yield and nutritional traits in germplasm of little millet ( Panicum sumatrense Roth. Ex. Roem. & Schult.)
Little millet (Panicum sumatrense Roth. Ex. Roem. & Schult.), a member of the
grass family Poaceae, is native to India. It is nutritionally superior to major cereals,
grows well on marginal lands, and can withstand drought and waterlogging
conditions. Two-hundred diverse little millet landraces were characterized to assess
variability for agronomic and nutritional traits and identify promising accessions.
Highly significant variabilitywas found for all the agronomic and grain nutrient traits.
Accessions of robusta were high yielding whereas those of nana were rich in grain
nutrients. About 80% of the accessions showed consistent protein and zinc (Zn) contents
whereas iron (Fe) and calcium (Ca) contents were less consistent (29.5 and
63.5%, respectively) over 2 yr. Promising trait-specific accessions were identified for
greater seed weight (10 accessions), high grain yield (15), high biomass yield (15),
and consistently high grain nutrients (30) over 2 yr (R2 = .69–.74, P ≤ .0001). A few
accessions showed consistently high for two or more nutrients (IPmr 449 for Fe, Zn,
Ca, and protein; IPmr 981 for Zn and protein). Five accessions (IPmr 855, 974, 877,
897, 767) were high yielding and also rich in Ca. Consumption of 100 g of little millet
grains can potentially contribute to the recommended dietary allowance of up to
28% Fe, 37% Zn, and 27% protein. Multilocation evaluation of the promising accessions
across different soil types, fertility levels, and climatic conditions would help
to identify valuable accessions for direct release as a cultivar or use in little millet
improvement