BACKGROUND The Green River Formation (early Eocene, about 42-53 Ma) at and near Fossil Butte National Monument in Wyoming, USA, is world famous for its exquisitely preserved freshwater teleost fish in the former Fossil Lake. Nonetheless, trace fossils attributed to fish interacting with the lake bottom are apparently rare, and have not been associated directly with any fish species. Here we int...

The techniques and capability to regenerate asexual embryos from walnut cotyledon tissue have been developed. Tissues from five Jug1ans regia cu1tivars, Jug1ans hindsii, and pterocarya sp. have been used. More than 100 asexual embryos have been selected from among the thousands produced. The sequence of procedures needed to obtain plants from these embryos have been worked out, and more than a ...

Hydra's remarkable capacity to regenerate, to proliferate asexually by budding, and to form a pattern de novo from aggregates allows studying complex cellular and molecular processes typical for embryonic development. The underlying assumption is that patterning in adult hydra tissue relies on factors and genes which are active also during early embryogenesis. Previously, we reported that in Hy...

The dorsal half of bisected Xenopus laevis embryos can regenerate a well-proportioned organism on a smaller scale. A new study indicates that the removal of ventral tissue generates a steeper Chordin gradient by reducing Sizzled, a secreted inhibitor of Tolloid chordinases.

background: morphine consumption during pregnancy could lead to defect and delay in nervous system development in the embryos. in the present study, development of the tongue of embryos whom their mothers received oral morphine during pregnancy have been studied. methods: female wistar rats (200-220 g) after pregnancy were divided randomly into the experimental and control groups. the control g...

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Although the rate of blastocysts implantation of embryos is higher than previous stages but their survival rate is lower than them, which could be attributed to the completely filled blastocoel cavity with liquid and increased possibility of the formation of ice crystals. This liquid could prevent the penetration of cryoprotecting materials into the embryos. In this study, we reduced the volume...

Protocols for the production and transformation of grapevine embryogenic cultures are described. Embryogenic cultures are initiated from leaves or stamens and pistils and transformed with Agrobacterium containing an enhanced green fluorescent protein/neomycin phosphotransferase II (egfp/nptII) fusion gene. Cultures are transferred to induction medium in the dark for callus formation and prolife...

The rules governing proximo-distal regeneration in the wing disc of Drosophila were investigated. It was found that proximal fragments confined to either anterior or posterior compartments could not regenerate distally, although many fragments having tissue from both compartments could do so even in the absence of circumferential regeneration. Fragments containing the ventral but not the dorsal...