Endocytosis of liposomes and intracellular fate of encapsulated molecules: Encounter with a low pH compartment after internalization in coated vesicles

Visualizing normal and defective bone development in zebrafish embryos using the fluorescent chromophore calcein

A Near‐Infrared Luminescent Label Based on YbIII Ions and Its Application in a Fluoroimmunoassay

Excerpt During the past 2 decades extraordinary advances have occurred in our understanding of the biology of normal cells. Dramatic progress has been made in defining the "molecular pathology" of ...

Metabolic Effects of Intracellular Infections in Man

The skeleton of the sea urchin embryo is synthesized by the primary mesenchyme cells (PMCs). Previous studies have shown that local interactions between PMCs and the neighboring ectoderm regulate several aspects of skeletal morphogenesis, including PMC distribution in the blastocoel, the size of the skeleton and its branching pattern. In the present study, we have further examined the regulation of skeletogenesis by the ectoderm. We generated a ‘rate map’ of skeletal growth, which revealed stereotypical changes in the rates at which specific skeletal elements elongate during development. We showed that three transcripts encoding PMC-specific gene products known to be involved in the synthesis of the skeleton exhibited dynamic, spatially regulated patterns of expression within the PMC syncytium. All three gene products showed high levels of expression at sites of skeletal rod growth, although the specific patterns varied among the genes. We present direct evidence, based upon cell transplantation experiments, that the expression of one of these genes, SM30, is responsive to local, ectoderm-derived cues. Based upon our studies, we suggest that short-range signals from different ectodermal territories may regulate the expression of PMC-specific gene products that are rate-limiting in skeletal biosynthesis, thereby locally influencing skeletal rod growth.

D. M. Surgenor

Papers

Preparation and Properties of 3,6-Dihydroxy-2,4-bis-[N-N´-di-(carboxymethyl)-aminomethyl] fluoran