Effects of cytochalasin B on fertilization and ploidy in the Pacific oyster Crassostrea gigas
نویسنده
چکیده
The effects of cytochalasin B on fertilization and ploidy in Crassostrea gigas were examined in a controlled experiment. This enabled us to better understand why variable ploidy results have been found with the retention ofpolar bodies in previous studies on bivalve mollusks, and what the interaction with fertilization may be. By looking at the early development of Crassas/rea gigas embryos with sequential sampies stained using Hoechst 33258, a fluorescent DNA-specific dye, we compared normal evolution of fertilized eggs with that obtained with cytochalasin B treatrnent. In treated eggs, embryos with both three and four pronuclei were found after the second meiotic division. When embryos had three pronuclei, these were identified as the female pronucleus plus two chromatin groups arising from the retention of the two polar bodies. The fourth pronucleus present in sorne embryos was the male pronucleus. The absence of the male pronucleus in the embryos with only three pronuc1ei was interpreted as gynogenetic development due to the inhibitory effects of cytochalasin B on penetration of the sperm into the eggs. This result explains the findings of several previous studies where different ploidies resulted from double polar body inh ibition in bivalve species. Implications ofsuch treatments for post-embryo genic development are discussed.
منابع مشابه
Optimization of tetraploid induction in Pacific oysters, Crassostrea gigas, using first polar body as a natural indicator
Tetraploid Crassostrea gigas were first successfully produced in 1993 by inhibiting the first Ž polar body of eggs from triploids that had been fertilized with sperm from diploids Guo and . Allen method . However, attempts to repeatedly produce high yields of tetraploids were inconsistent. Because of these uncertainties, we examined some of the fundamental aspects of tetraploid production in an...
متن کاملThe Effects of 4-nonylphenol on the Immune Response of the Pacific Oyster, Crassostrea Gigas, following Bacterial Infection (vibrio Campbellii)
متن کامل
Development of Genetic Markers for Triploid Verification of the Pacific Oyster, Crassostrea gigas
The triploid Pacific oyster, which is produced by mating tetraploid and diploid oysters, is favored by the aquaculture industry because of its better flavor and firmer texture, particularly during the summer. However, tetraploid oyster production is not feasible in all oysters; the development of tetraploid oysters is ongoing in some oyster species. Thus, a method for ploidy verification is nec...
متن کاملColonisation of the Non-Indigenous Pacific Oyster Crassostrea gigas Determined by Predation, Size and Initial Settlement Densities
Survival of incipient non-indigenous populations is dramatically altered by early predation on new colonisers. These effects can be influenced by morphological traits, such as coloniser size and density. The Australian non-native Pacific Oyster Crassostrea gigas is generally more fecund and faster growing compared to the native Saccostrea glomerata found in the same habitat. It is therefore imp...
متن کاملEffects of temperature and salinity on haemocyte activities of the Pacific oyster, Crassostrea gigas (Thunberg).
The Pacific oyster, Crassostrea gigas, is extensively cultivated and represents an important economic activity. Oysters are reared in estuarine areas, subjected to various biotic and abiotic factors. One of the limiting factors in aquaculture is mortality outbreaks, which may limit oyster production, and the causes of these outbreaks are not completely understood. In this context, the effects o...
متن کامل