β-hexosaminidase from Xenopus laevis eggs and oocytes: from gene to immunochemical characterization.

Glycosidases are present both in sperm and eggs in vertebrates and have been associated with different fertilization steps as gamete binding, egg coat penetration, and polyspermy prevention. In this manuscript, we have analyzed the activity of different glycosidases of Xenopus laevis eggs. The main activity corresponded to N-acetyl-β-D-glucosaminidase (Hex), which was reported to participate both in gamete binding and polyspermy prevention among phylogenetically distant animals.

Growth hormone receptors in zebrafish (Danio rerio): adult and embryonic expression patterns.

Growth hormone receptor (GHR) is a critical regulator of growth and metabolism. Although two GHRs have been characterized in many fish species, their functional characteristics, mechanisms of regulation and roles in embryonic development remain unclear. The zebrafish (Danio rerio) is an excellent model organism to study both developmental and physiological processes.

Bacterial sensing of and resistance to gold salts.

The MerR family is a group of bacterial transcriptional regulators that respond to different environmental stimuli, such as heavy metals, oxidative stress or antibiotics. Here we characterize a new member of this family that is highly selective for Au ions. We show that this Salmonella regulator, named GolS, directly controls the expression of at least two transcriptional units specifically required for Au resistance.