Ca2+-ions and pattern control in Hydra.

Area of Science:

• Developmental Biology
• Animal Physiology
• Cell Biology

Background:

• Freshwater polyp Hydra forms buds that develop a foot and detach.
• Certain compounds (phorbolesters, diacylglycerols, cantharidin, Li+-ions) inhibit foot formation in Hydra vulgaris (Zürich), causing buds to form branches.
• Different Hydra strains exhibit varying sensitivities to these treatments.

Purpose of the Study:

• To investigate the role of calcium (Ca2+) ions in bud-to-branch transformation in Hydra.
• To compare the sensitivity of different Hydra strains to altered calcium ion concentrations.
• To elucidate the mechanism by which various treatments affect foot formation.

Main Methods:

• Culturing Hydra vulgaris (Zürich) and other strains in media with varying Ca2+ ion concentrations.
• Treating Hydra with barium (Ba2+) and strontium (Sr2+) ions.
• Observing and comparing bud morphology (foot vs. branch formation) across different conditions and strains.

Main Results:

• Reduced Ca2+ ion concentration in the culture medium induced branch formation specifically in the H. vulgaris (Zürich) strain.
• Enrichment of the medium with Ba2+ and Sr2+ ions caused all tested strains to form branches.
• H. vulgaris (Zürich) demonstrated higher sensitivity to treatments affecting Ca2+ levels, suggesting efficient Ca2+ pumps.

Conclusions:

• Calcium ion concentration is a critical regulator of bud development in Hydra.
• Treatments likely reduce internal Ca2+ levels by promoting export or competing with Ca2+ at target sites.
• The high Ca2+ sensitivity of H. vulgaris (Zürich) may be an adaptation to its native calcium-rich lake environment.