Induction of Secondary Embryos by Intra- and Interspecific Grafts of Center Cells under the blastopore in Horseshoe Crabs

When the cell mass (center cells) of the early gastrulae in both American and Asian horseshoe crabs was grafted into the embryo of the homologous species, secondary embryos were formed as a result of these grafts. Secondary embryos were also formed in a similar way when the center cells of heterologous embryos were grafted between the American and Asian horseshoe crab embryos. The characteristics of the secondary embryos were similar to the host embryos in both cases, indicating that the center cells played the roles same as those by the amphibian organizer. The homogenate of center cells also induced the formation of secondary embryos. This is the first published study in which secondary embryos of horseshoe crabs have been induced by grafting. The fact may mean that this type of embryonic induction is widespread in the animal kingdom.     

Incomplete synthesis of the Sd/Cad blood group carbohydrate in gastrointestinal cancer

Cancer-associated changes in cell surface carbohydrates, including incomplete synthesis of normal carbohydrate epitopes, strongly affect malignant and metastatic potential. Here, we report that compensating for the cancer-associated loss of a single glycosyltransferase, β1,4N-acetylgalactosaminyltransferese T2, dramatically decreased cell surface expression of both E-selectin ligands (sialyl Lewis^x and sialyl Lewis^a). This modification was associated with elevated expression of the Sd^a carbohydrate determinant, which is expressed in normal gastrointestinal mucosa and is strikingly downregulated in cancer tissues. Loss of E-selectin ligands resulted in decreased adhesion of cancer cells to activated human endothelial cells in vitro and eventually suppressed metastatic potential in vivo.     

Fmoc-based solid phase chemical synthesis of 71-meric neuregulin 1-beta1, an epidermal growth factor-like domain.

The human neuregulin 1-beta1 (NRG1-beta1, amino acid residues 176-246) was chemically synthesized by Fmoc-based solid phase peptide synthesis (SPPS) followed by folding in a redox buffer. The biological activity of the synthesized NRG1-beta1 was confirmed by ligand-induced tyrosine phosphorylation on Chinese hamster ovary (CHO) cells expressing ErbB-4.     

Separation of keratinocytes by density gradient centrifugation for DNA cytofluorometry

A method for the separation of guinea pig epidermal keratinocytes, in which the Feulgen-stainable material suffers minimal damage, has been investigated. The principal stage involves trypsin treatment of the epidermal sheet, stripped from the dermis with ethylenediamine tetraacetic acid. The epidermal cells thus isolated are separated into three groups by centrifugation on a continuous colloidal silica (Percoll) density gradient. The resulting arrangement of the keratinocytes in the centrifuge tube corresponds to their arrangement in situ, with basal cells at the bottom and the more differentiated cells above. By morphological examination, it can be shown that relatively pure fractions of basal cells, spinous cells, and granular cells are obtained by this method. With respect to DNA distribution pattern, there was good agreement between that of keratinocytes separated by the microdissection-ultrasonic irradiation method, or by the chymotrypsin method as reported previously by us, and that obtained by the present method.     

The radiation response of SCCVII tumor cells in C3H/He mice varies with the irradiation conditions

The radiation response of SCCVII tumor cells in C3H/He mice under various irradiation conditions was studied using an in vivo-in vitro assay. When tumor-bearing mice were irradiated without anesthesia or physical restraint, the tumor had a hypoxic fraction of 5.4%. Both anesthesia and immobilization of the tumor-bearing leg with adhesive tape produced significant increases in the hypoxic fraction (23 and 28%, respectively). Restraining the mouse in a jig without immobilizing the tumor-bearing leg also increased the hypoxic fraction (13%).     

Organ culture of chicken cecum: Morphologic and physiologic observations after 24 and 48 h of culture

Summary Cecum from chickens, 4 wk old, can best be maintained for 24 h in a serum-free organ culture system using Trowell T8 medium agar sheet at 25°C. As determined by light microscopy as well as scanning and transmission electron microscopy, mucosal architecture involving classic ultrastructure of chicken cecal mucosa was preserved. Protein content of cecal explants did not change up to 48 h of culture. DNA content of cecal explants did not change up to 24 h of culture but decreased significantly to two-thirds of control in 48 h of culture. Based on the morphologic and physiologic findings, it became evident that this organ culture system using Trowell T8 medium at 25°C can be successfully used as an in vitro experimental model for as long as 24 h. The organ culture system could be a useful tool, from the structural integrity of ceca observed in this study, in investigating mucosal function and mucosal response to drugs, carcinogens, trophic factors, and pathogens.     

Induction of multinucleation by β-glucosyl Yariv reagent in regenerated cells from <Emphasis Type="Italic">Marchantia polymorpha</Emphasis> protoplasts and involvement of arabinogalactan proteins in cell plate formation

Arabinogalactan proteins (AGPs) are abundant plant cell surface proteoglycans widely distributed in plant species. Since high concentrations of β-glucosyl Yariv reagent (βglcY), which binds selectively to AGPs, inhibited cell division of protoplast-regenerated cells of the liverwort Marchantia polymorpha L. (Shibaya and Sugawara in Physiol Plant 130:271–279, 2007), we investigated the mechanism underlying the inability of the cells to divide normally by staining nuclei, cell walls and β-1,3-glucan. Microscopic observation showed that the diameter of regenerated cells cultured with βglcY was about 2.8-fold larger than that of cells cultured without βglcY. The cells cultured with βglcY were remarkably multinucleated. These results indicated that βglcY did not inhibit mitosis but induced multinucleation. In the regenerated cells cultured with low concentrations of βglcY (5 and 1 μg ml⁻¹), the cell plate was stained strongly by βglcY, suggesting abundant AGPs in the forming cell plate. In these cell plates, β-1,3-glucan was barely detectable or not detected. In multinucleated cells, cell plate-like fragments, which could not reach the cell wall, were frequently observed and they were also stained strongly by βglcY. Our results indicated that AGPs might have an important role in cell plate formation, and perturbation of AGPs with βglcY might result in remarkable multinucleation in protoplast-regenerated cells of M. polymorpha. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

A preliminary study of the movements of yellow and silver eels, Anguilla japonica, in the estuary of the Fukui River, Japan, as revealed by acoustic tracking

The behavior and movements of yellow and silver phase Japanese eels were observed using acoustic telemetry in the Fukui River estuary and the adjacent waters of Tachibana Bay, Tokushima Prefecture, Japan. The eels were tagged with ultrasonic transmitters and released in the bay, about 300 m from the river mouth in August and November, 1999. All four yellow eels released at the river mouth in August returned to the river. All eels swam further upstream and each stopped at similar locations as the others, which were possibly used as refuges. Each refuge appeared to be a relatively small area (less than 10 m) adjacent to a series of concrete blocks along the shore (100–300 m). These areas were repeatedly utilized by all the yellow eels tracked during the study. The yellow eels spent most of their time in these refuges during daytime and moved predominantly at night. In contrast, a silver eel released in November demonstrated rapid movement towards the sea without stopping after release.