The genes coding for yellow pigment production in Erwinia herbicola Eho10 (ATCC 39368) were cloned and localized to a 12.4-kilobase (kb) chromosomal fragment. A 2.3-kb AvaI deletion in the cloned fragment resulted in the production of a pink-yellow pigment, a possible precursor of the yellow pigment. Production of yellow pigment in both E. herbicola Eho10 and pigmented Escherichia coli clones w...

When the minimal renal threshold for blood hemoglobin is exceeded there is observed a deposit of iron staining pigment in the epithelium of the renal convoluted tubules. At a certain point this epithelium cannot take up more hemoglobin and this coincides with the minimal renal threshold level. When the injections of blood hemoglobin are kept below the minimal renal threshold level we note a com...

Retinas of adult teleost fish can regenerate after injury. Two important issues regarding this phenomenon are the assembly of the regenerated retina and the neuronal images of the visual scene that the regenerated retina produces. Here we report experiments in which the visual pigment content of photoreceptors derived from native and regenerated sunfish retinas was determined by microspectropho...

PURPOSE To investigate the mechanism(s) by which intracellular cAMP levels are elevated to induce pigment granule aggregation in teleost retinal pigment epithelium (RPE). METHODS Pigment granule migration was studied in vitro using RPE sheets isolated from dark-adapted green sunfish, Lepomis cyanellus. After preculture to allow pigment granule dispersion, RPE sheets were incubated with variou...

1. Retina pigment epithelium cells and iris pigment cells are placed in an identical medium. 2. The differentiation into two different parts, as well as the pigment strains of the migrating pigment epithelium cells, is lost. The normally highly specialized cuticular structures disappear. The cells begin to move and assume a spindle shape, thus losing their original hexagonal shape. 3. The migra...

Many mutants that disrupt zebrafish embryonic pigment pattern have been isolated, and subsequent cloning of the mutated genes causing these phenotypes has contributed to our understanding of pigment cell development. However, few mutants have been identified that specifically affect development of the adult pigment pattern. Through a mutant screen for adult pigment pattern phenotypes, we identi...

* Arbeitsgruppe Sehphysiologie. Abteilung für Biologie. Ruhr-Universität. D-4630 Bochum, Bundesrepublik Deutschland ** D epartm ent of Physiology, Karolinska Institute, S-10401 Stockholm, and D epartm ent of Occupational Neuromedicine, National Board of Occupational Safety and H ealth, S-17184 Solna, Sweden Z. Naturforsch. 42c, 973—976 (1987); received October 13, 1986/March 18. 1987 Screening ...

The retinal pigment epithelium is an important part of the vertebrate eye, particularly in studying the causes and possible treatment of age-related macular degeneration. The retinal pigment epithelium is difficult to access in vivo due to its location at the back of the eye, making experimentation with age-related macular degeneration treatments problematic. An alternative to in vivo experimen...

The fitness of male guppies (Poecilia reticulata) highly depends on the size and number of their black, blue, and orange ornaments. Recently, progress has been made regarding the genetic mechanisms underlying male guppy pigment pattern formation, but we still know little about the pigment cell organization within these ornaments. Here, we investigate the pigment cell distribution within the bla...

Staphylococcus aureus mutants lacking pigment, or expressing only low levels of pigment, were more sensitive to oleic acid than were the parent strain and mutants making more pigment than the parent. One class of mutants (colour index 5), although possessing significant levels of pigment, were nevertheless quite sensitive to oleic acid. This suggested that only certain carotenoids in the biosyn...