RESUMEN
Our previous study documented expression of a male-transmitted cytochrome c oxidase subunit II protein (MCOX2), with a C-terminus extension (MCOX2e), in unionoidean bivalve testes and sperm mitochondria. Here, we present evidence demonstrating that MCOX2 is seasonally expressed in testis, with a peak shortly before fertilization that is independent of sperm density. MCOX2 is localized to the inner and outer sperm mitochondrial membranes and the MCOX2 antibody's epitope is conserved across >65 million years of evolution. We also demonstrate the presence of male-transmitted mtDNA and season-specific MCOX2 spatial variation in ovaries. We hypothesize that MCOX2 plays a role in reproduction through gamete maturation, fertilization and/or embryogenesis.
Asunto(s)
Complejo IV de Transporte de Electrones/genética , Complejo IV de Transporte de Electrones/fisiología , Óvulo/enzimología , Espermatozoides/enzimología , Unionidae/genética , Unionidae/fisiología , Animales , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Complejo IV de Transporte de Electrones/química , Evolución Molecular , Femenino , Masculino , Microscopía Electrónica , Reproducción/genética , Reproducción/fisiología , Estaciones del Año , Distribución TisularRESUMEN
The conglutinate of the creeper, Strophitus undulaus (Say, 1817) (Unionoidea: Unionidae), was studied with light and scanning electron microscopy. This conglutinate has a very simple structure consisting of a homogeneous, spongy material containing the glochidia. Each glochidium is contained within its egg membrane and is tethered to this membrane by the glochidial thread. Within the female's marsupium, the glochidia are contained within the conglutinate. When they are expelled to the water the glochidia emerge through pores to the outside and become infective. The mechanism for pushing the glochidia out of the conglutinate is osmotic. The marsupium apparently bathes the conglutinates in a hypertonic solution. When conglutinates are expelled to the surrounding hypotonic water, the spongy material of the conglutinate swells, pushing the glochidia out through the pores. Unlike other conglutinates studied, that of S. undulatus displays a brief period of innate motion which may be adaptive in attracting a suitable host.
RESUMEN
1. Acetyl coenzyme A carboxylase from lactating rat mammary gland has been purified to apparent homogeneity. 2. The purified enzyme has the following characteristics: (a) its specific activity approaches 15 units/mg of protein, (b) the sedimentation constants of the protomeric and polymeric forms of the enzyme are 12 to 13 S and greater than or equal to 40 S, respectively, (c) the polymeric form of the enzyme shows filamentous structures in the electron microscope, and (d) the polypeptide(s) arising from its dissociation reveals a single major component of Mr = 240,000 to 260,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 3. The enzyme contains 1 mol of biotin and approximately 6 mol of phosphate/240,000 g of protein.