Xenopus laevis embryos can establish their spatial bilateral symmetrical body pattern without gravity

Area of Science:

• Developmental Biology
• Space Biology
• Embryology

Background:

• Gravity's role in establishing embryonic bilateral symmetry is assumed, especially in yolky eggs.
• Previous experiments fertilized Xenopus laevis eggs in space (1988, 1989).

Purpose of the Study:

• To investigate embryonic development and bilateral symmetry establishment in Xenopus laevis under microgravity.
• To determine if sperm alone can cue bilateral symmetry in the absence of gravity.

Main Methods:

• Artificially fertilized Xenopus laevis eggs were developed in automated hardware under microgravity conditions during the IML-1 Space Shuttle mission.
• Embryos were histologically fixed during the gastrulation stage, timed according to Earth-based development.

Main Results:

• Artificially fertilized Xenopus eggs initiated embryonic development in microgravity.
• Gastrulae were successfully fixed, confirming development occurred in near weightlessness.
• The study provides evidence for bilateral symmetry development in Xenopus embryos under microgravity.

Conclusions:

• Xenopus embryos can develop bilaterally symmetrically after fertilization in microgravity.
• Sperm likely plays a crucial role in cueing bilateral symmetry, independent of gravitational forces.