The production of color variants of Serratia marcescens by means of ultraviolet light irradiation has been reported by Labrum and Bunting (1953). These variants exhibited several shades of pink, orange, or white pigmentation, and differed markedly from the natural or wild-type red color. Rizki (1954a) demonstrated that several of these pink, orange, and white variants were capable of inducing r...

PURPOSE To determine the functional defects in two male patients with progressive cone dystrophy and hybrid L-M cone pigment genes. METHODS Clinical evaluation, standard electroretinography, and electrooculography were performed in two affected patients and two family members. Measurements of spectral sensitivity and transient tritanopia were made in both patients. RESULTS In the patients, ...

The ocelli of Archaeognatha, or jumping bristletails, differ from typical insect ocelli in shape and field of view. Although the shape of the lateral ocelli is highly variable among species, most Machiloidea have sole-shaped lateral ocelli beneath the compound eyes and a median ocellus that is oriented downward. This study investigated morphological and physiological aspects of the ocelli of Ma...

PURPOSE To report a case of cancer-associated nummular loss of the retinal pigment epithelium. METHODS A 47-year-old man with a history of hepatocellular carcinoma presented with three weeks of bilateral visual loss. His best-corrected visual acuity was 20/40 in each eye. He had multiple round confluent grayish-brown patches at the level of retinal pigment epithelium, and no pigmented choroid...

Foveal threshold elevation and red-green cone pigment regeneration have been studied in the dark after a wide range of bleaches in normal man with a view to probing the limits of the application of the Dowling-Rushton relation: i.e., the direct proportionality between log threshold elevation and fraction of unregenerated pigment. Cone pigment regeneration (and threshold recovery) is much faster...

1. The blue-green alga Anacystis nidulans was cultured under steady state conditions at 25 and 39 degrees C. and under several different light intensities to give five different types of cells. 2. Cells were submitted to pigment analysis based upon acetone extracts and aqueous extracts obtained by sonic disintegration. The different cell types show a threefold range of chlorophyll content and a...

Tests of color vision and unique hue judgments were carried out on a patient with little cone function and abnormal macular pigmentation and optic nerve appearance. These tests revealed weak cone-based dichromatic color vision yet normal red, green, and blue unique hue judgments. In addition, rod input was found to inhibit color discrimination. Genetic analysis revealed the absence of L pigment...