Embryo defenses

Embryos are tough. With no more than a single cell, the earliest stages of life must survive in the ocean. Their strategy is to have heavy duty mechanisms to ward off infection, keep out toxic chemicals, shield from the sun, prevent breaking in the waves and survive when food or air are scarce. These mechanisms determine the success or failure of development in the real world.


My interests center around understanding the cellular and molecular tools embryos use to solve these environmental challenges. To learn more about the biology of the embryo defenses in animal embryos I primarily study sea urchins. These animals produce millions of eggs that can be easily manipulated in the laboratory to produce robust embryos.


A key protective tool is a group of proteins called multidrug transporters. These molecules are cellular pumps, keeping chemicals from building up inside the embryo and “flooding” the cell. They can be thought of as cellular “bouncers”, determining which chemicals get in and which ones are kept out. Sea urchins have large amounts of the multidrug transporter.


Once active, the transporters can keep a variety of chemicals from building up inside the embryo. This has important implications for the ability of these embryos to keep both natural and man-made toxic chemicals out of the cell. If these transporters are overwhelmed by chemicals, or fail to recognize them, the chemicals enter the cell and build up inside embryos.


Both environmental contaminants and pharmaceutical drugs can elude transporters in this way. Some of these same chemicals can also adversely affect the survival or embryos in the environment. By unraveling the mysteries of how embryo defenses work we gain insights into why myriad chemicals in the environment and our bodies, are problematic for embryos.

 


Education


Ph.D., 2003, Physiology, UC Davis

Postdoctoral Fellow, Stanford University 2003-Present



Embryo images





3D confocal micrograph

of a 2-cell sea urchin

embryo (Photo: Amro Hamdoun).





Sea urchin larvae with polyaromatic hydrocarbon (PAH)-inhibited efflux transporter activity (Photo: Amro Hamdoun).



Contact


Hopkins Marine Station

Oceanview Blvd.

Pacific Grove CA 93950

hamdoun(at)stanford.edu



















 

Amro Hamdoun