scispace - formally typeset
Search or ask a question
Topic

Uca pugilator

About: Uca pugilator is a research topic. Over the lifetime, 376 publications have been published within this topic receiving 12303 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: Crab protease is a good general protease capable of degrading a variety of polypeptide and synthetic low molecular weight substrates and is effectively inhibited by chymostatin but not by leupeptin or elastatinal.
Abstract: The collagenolytic protease from Uca pugilator was studied with respect to its catalytic properties on collagen types I-V. The crab protease degraded all five collagen types, producing multiple cleavages in the triple helix of each native collagen at 25 degrees C. The major early cleavage in the alpha 1 polypeptide chain of collagen types I-III occurred at a 3/4:1/4 locus, resulting in fragments electrophoretically similar to the TCA and TCB products of mammalian collagenase action. Interestingly, a propensity toward this same cleavage was observed even following thermal denaturation of the substrates. The ability of the crab protease to degrade all native collagen types and to catalyze cleavages at multiple loci in the triple helix distinguishes its action from that of mammalian collagenases. The collagenolytic activity of the crab protease was also examined on fibrillar collagen and compared to that of human skin fibroblast collagenase. Enzyme concentrations of fibroblast collagenase which resulted in the saturation of available substrate sites failed to show such an effect in the case of the crab protease. Binding studies of the crab protease to fibrillar collagen likewise indicated substantially reduced levels of enzyme binding in comparison to fibroblast collagenase. These data suggest that the affinity of the crab protease for native collagen is considerably less than the affinity of mammalian collagenase for this substrate.

60 citations

Journal ArticleDOI
TL;DR: It is concluded that serotonin acts primarily on the central nervous system to stimulate the release of a red pigment-dispersing hormone, whereas the red pigment’s hormone stimulates the erythrophores directly.

59 citations

Journal ArticleDOI
TL;DR: It is shown that the ecdysteroid receptor in the fiddler crab (UpEcR) behaves differently depending upon the UpRXR isoform with which it is partnered, and the two sets of heterodimers tested here may represent different dynamic complexes whose properties are defined by the specific heterodimeric subunits involved and the specific ligands available.
Abstract: The pleiotropic effects of circulating ecdysteroids in the adult fiddler crab, Uca pugilator, during molting, regeneration, and reproduction are mediated by a limited number of receptor proteins. We hypothesize that hormonal effects in vivo may be the result of complex interactions between at least two receptor heterodimer conformations that differentially respond to multiple ecdysteroid/retinoid signals. Two splicing variants of the fiddler crab retinoid-X-receptor (UpRXR) differ from one another by the addition of a 33 amino acid insert in the ligand-binding domain. We show here that the ecdysteroid receptor in the fiddler crab (UpEcR) behaves differently depending upon the UpRXR isoform with which it is partnered. The two UpRXR variant partners for UpEcR confer slightly different responses in the binding of Ponasterone A (PA)-a naturally occurring ecdysteroid in the blood of Uca. UpRXR can bind 9-cis retinoic acid (9cRA) as well as terpenoids. 9cRA and the naturally occurring terpenoid, methyl farnesoate, influence the binding of PA to UpEcR/UpRXR dimers. Endogenous retinoids are found in the blastema of regenerating limbs of Uca and they (plus blood-borne terpenoids) may add additional levels of differential response by target tissues. Thus, the two sets of heterodimers tested here may represent different dynamic complexes whose properties are defined by the specific heterodimeric subunits involved and the specific ligands available.

59 citations

Journal ArticleDOI
TL;DR: The combined effects of receptor knockdown indicate that, although circulating ecdysteroid titers are normally low during basal limb bud growth, signaling via the EcR/RXR receptor pathway is necessary for establishment of blastemal cell proliferation and development in the regenerating limbs of U. pugilator.

58 citations

Journal ArticleDOI
TL;DR: Under conditions of constant darkness the red chromatophores of Uca pugilator show a striking persistent daily rhythmicity, dispersing their pigment by day, and concentrating it by night.
Abstract: 1. The red chromatophores of Uca pugilator, when other factors are equal, exhibit extensive responses to background. They disperse their pigment upon a black background, and concentrate it upon a white one.2. Under conditions of constant darkness the red chromatophores show a striking persistent daily rhythmicity, dispersing their pigment by day, and concentrating it by night.3. Extracts of sinus glands, and all of the major portions of the central nervous system, possess strong activity upon the red chromatophores. All portions exhibit two types of activity due to the possession of two principles. One of the activities is red-concentration and the other, red-dispersion.4. The action of the red-concentrating principle can dominate the response when there is, concurrently present, high concentrations of both red-dispersing and red-concentrating principles.5. The red-concentrating activity of all extracts is of much shorter duration than is the red-dispersing activity, the latter often lasting 3 to 4 times ...

58 citations


Network Information
Related Topics (5)
Mating system
4.2K papers, 225.3K citations
73% related
Avian clutch size
5K papers, 186.9K citations
73% related
Sexual dimorphism
7K papers, 249.8K citations
73% related
Reproductive success
8.1K papers, 354.8K citations
73% related
Predation
22.6K papers, 881.2K citations
72% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20211
20176
20162
20153
20146
20137