Crustacean eye fine structure seen with scanning electron microscopy

An electromagnetic theory of life--II: Testing

Serious problems and contradictions face the long-standing chemical reaction theory of life. Arguments favoring an alternative view featuring electromagnetic micromechanisms were presented in the December 1989 issue of this Journal (27, 31). However, the theory had an extremely general form which was forbidding to laboratory demonstration. It became clear that its essentially conceptual form needed to be transformed to a testable theory which ultimately could lead to laboratory verification. Now, with the recognition of the role of chaos theory in finding order within chaos in the kinetics of cell metabolism, the electromagnetic theory of life has become better grounded and more amenable to laboratory testing and evaluation. I thus focus on certain theoretical advances as well as the application of new technologies to test the hypothesis of 5 specific target areas. With the verification of electromagnetic processes in life, we anticipate that the biomedical sciences will be propelled to a wealth of solutions to many vexing problems.

Distinct lobes of Limulus ventral photoreceptors. I. Functional and anatomical properties of lobes revealed by removal of glial cells

Removing the glial cells that encase Limulus ventral photoreceptors allows direct observation of the cell surface. Light microscopy of denuded photoreceptors reveals a subdivision of the cell body into lobes. Often one lobe, but sometimes several, is relatively clear and translucent (the R lobes). The lobe adjacent to the axon (the A lobe) has a textured appearance. Scanning electron microscopy shows that microvilli cover the surface of R lobes and are absent from the surface of A lobes. When a dim spot of light is incident on the R lobe, the probability of evoking a single photon response is two to three orders of magnitude higher than when the same spot is incident on the A lobe. We conclude that the sensitivity of the cell to light is principally a function of the R lobe.

Photomechanical responses in crustacean retinula cells: the role of microtubules

Light and darkness promote opposite migrations of screening pigment granules in the retinal photoreceptors of the crayfish and other arthropods, and microtubules have been implicated in this part of the adaptation process. This report considers the topographic relationships of the migratory pigment granules with the microtubular system of the cells. Scanning electron microscopy was used to obtain a three-dimensional visualization of the internal organization of cells in different states of adaptation. Many pigment granules were found directly associated with the microtubular array, although most of them are not adjacent to microtubules irrespective of the adaptation conditions. However, the granules appear associated with each other and form extensive clusters or possibly a single conglomerate. Therefore, interaction of a limited number of granules with the microtubules could affect the movement of the whole granule population. When the pigment complex withdraws, many microtubules are still seen in the deserted regions. It is concluded that the microtubules might represent a supporting framework for the translocation of the pigment, which appears to move as a coherent mass rather than as independent particles.