Biomass of the crustacean Artemia sp. has multiple uses. The biochemical composition and biomass production of Artemia grown from cysts produced by a native population from Real de Salinas were evaluated under laboratory conditions. Nauplii (instar I) were stocked at density of 10 nauplii/ml in 1.5 l tanks, fed with rice bran from day 2 to day 6, and with the microalgae Tetraselmis suecica from...

The problem of the maintenance of anisogamous sex is addressed by considering the effect of fertilization on the fitness of parthenogenetic females when such fertilization yields inviable triploid progeny. We consider four types of parthenogenesis: (i) apomixis, (ii) homogametic amphimixis, (iii) heterogametic amphimixis, and (iv) homogametic automixis. Homozygous sexual populations are genetic...

Mammalian parthenogenetic embryos invariably die in mid-gestation from imprinted gene defects and placental hypoplasia. Based on chimera experiments, trophoblastic proliferation is supposed to be inhibited in the absence of a male genome. Here, we show that parthenogenetic mouse embryonic cell nuclei can be reprogrammed by serial rounds of nuclear transfer without using any genetic modification...

Filter-feeding organisms are often keystone species with a major influence on the dynamics of aquatic ecosystems. Studies of filtering rates in such taxa are therefore vital in order to understand ecosystem functioning and the impact of natural and anthropogenic stressors such as parasites, climate warming and invasive species. Brine shrimps Artemia spp. are the dominant grazers in hypersaline ...

The objective of this study was to determine the effects of 3 chemical agents used sequentially and electrical stimuli on parthenogenetic activation of in vitro matured bovine oocytes and comparison with a standard IVF protocol for embryo developmental rates. For this purpose, oocytes were matured in tissue culture medium-199 (TCM-199) at 39 °C and 5% of CO2 in humidified air. For IVF, matured ...

The burrowing polymitarcyid mayfly Ephoron shigae is distributed across Japan, Korea, northeast China and far east Russia. Some populations are bisexual, and others are unisexual, i.e. geographically parthenogenetic throughout Japan. In general, parthenogenetic organisms are often found in harsh environments, such as at high latitudes and altitudes, in xeric as opposed to mesic conditions, in i...

PPROXIMATELY 17% of the eggs laid by non-mated Beltsville Small A White (BSW) turkeys showed some type (e.g., membranes, blood, embryos) of development upon incubation ( OLSEN and MARSDEN 1953,1954). The question arose as to whether the cells in such unfertilized eggs were haploid or diploid. YAO and OLSEN (1955) reported finding diploid chromosome numbers in embryonic tissue of parthenogenetic...

Parthenogenetic activation of mammalian oocytes with artificial stimuli is commonly applied in various reproductive biotechniques, e.g. cloning using nuclear transfer. For this reason, many studies focus on oocyte activation in vitro. Recently we have described the activation of pig oocytes using nitric oxide. This activating stimulus is very specific in many aspects. However, it does not provi...