Teleost eyes grow throughout life by adding neurons and stretching extant tissue. New retinal neurons of all types are added at the ciliary margin and new rod photoreceptors are inserted throughout retina in the outer nuclear layer (ONL). New rod photoreceptors result from the division of progenitor cells located in the ONL amidst functioning rod photoreceptor cell nuclei, but it is not known h...

At very low light levels the sensitivity of the visual system is determined by the efficiency with which single photons are captured, and the resulting signal transmitted from the rod photoreceptors through the retinal circuitry to the ganglion cells and on to the brain. Although the tiny electrical signals due to single photons have been observed in rod photoreceptors, little is known about ho...

Leber congenital amaurosis (LCA) caused by mutations in Aryl hydrocarbon receptor interacting protein like-1 (Aipl1) is a severe form of childhood blindness. At 4 weeks of age, a mouse model of LCA lacking AIPL1 exhibits complete degeneration of both rod and cone photoreceptors. Rod cell death occurs due to rapid destabilization of rod phosphodiesterase, an enzyme essential for rod survival and...

The rod component of the bacterial flagellum polymerizes from the inner membrane across the periplasmic space and stops at a length of 25 nm at the outer membrane. Bushing structures, the P- and L-rings, polymerize around the distal rod and form a pore in the outer membrane. The flagellar hook structure is then added to the distal rod growing outside the cell. Hook polymerization stops after th...

The retina offers a model system for investigating the mechanisms that control cell type determination and differentiation in the vertebrate central nervous system. Previously, rod photoreceptor development in vitro was found to require a diffusible activity released by retinal cells (D. Altshuler and C. Cepko, Development 114, 947-957, 1992). In this report, we show that retinal-cell-condition...

PURPOSE Because of their high cone/rod ratio, Xenopus laevis may be a useful system for examining rod-cone interactions during retinal degeneration and mechanisms that underlie secondary cone degeneration. The authors developed an inducible model of retinitis pigmentosa (RP) in X. laevis to investigate these issues. METHODS The authors generated transgenic X. laevis that express a modified ca...

Anatomical and physiological studies of the mammalian retina have revealed two primary pathways available for the transmission of rod signals to the ganglion cells: one via ON rod bipolars, amacrine II cells, and ON and OFF cone bipolars, which is exquisitely designed for the transmission of single-photon absorption events; and a second via rod-cone gap junctions, and ON and OFF cone bipolars, ...

A viscoelastic rod model which includes damping has been used to simulate the spinal column mathematically. This one-dimensional rod was subjected to a ramp input acceleration and the theoretical acceleration at the end of the rod was compared to the experimental head acceleration data from previously conducted cadaver t&s. The agreement between the experimental and theoretical results is bette...