The complete chloroplast genome of the green microalgae strain SQ.

The complete chloroplast genome of the microalgae strain SQ was determined in this study. The total length of the chloroplast genome is 243,635 bp with 29.73% GC content.

MAPK is involved in metaphase I arrest in oyster and mussel oocytes.

Oocytes of Crassostrea gigas and Mytilus galloprovincialis are arrested in metaphase I when they are spawned and ready to be fertilized. To investigate the role of MAP kinase in maintaining metaphase I arrest, oocytes were exposed to the MEK inhibitor U0126, and the effects on chromosome behavior and MAPK activity were examined by bisbenzimide staining and in immunoblots with anti-phospho MAPK antibodies. Following treatment with 50 microM U0126, active MAPK was undetectable and oocytes resumed meiosis, forming enlarged polar bodies and undergoing chromosome decondensation.

Polyspermy prevention in marine invertebrates.

In marine invertebrates, as in most other organisms, normal development requires that only one sperm nucleus joins with the egg nucleus at fertilization. The principal mechanisms employed are (1) prevention of sperm-egg plasma membrane fusion and (2) modifications of the egg extracellular coat to prevent sperm binding and/or penetration. In a third strategy, fertilization is polyspermic, but only one sperm nucleus fuses with the egg nucleus.