Uca pugilator

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

The roles of hemocytes in tanning during the molting cycle: a histochemical study of the fiddler crab, uca pugilator

Abstract: Histochemical data support the previous biochemical finding that the blood is a major site for the production of proteinaceous and diphenolic substances for tanning of the cuticle in the fiddler crab, Uca pugilator. Five types of hemocytes are described. Specifically in tanning, the hyaline cells (cystocytes) appear responsible for the production of diphenolic tanning agents whereas the granulocytes synthesize the proteins involved. Other types of hemocyte may be transitional forms involved in clotting (intermediate cells). Various histochemical reactions for each type of hemocyte and the cuticle are recorded throughout the molting cycle, and appear cyclic. The data suggest there is hormonal control of the cyclic events during the tanning process.

Collagenolytic serine protease PC and trypsin PC from king crab Paralithodes camtschaticus: cDNA cloning and primary structure of the enzymes

Abstract: In this paper, we describe cDNA cloning of a new anionic trypsin and a collagenolytic serine protease from king crab Paralithodes camtschaticus and the elucidation of their primary structures. Constructing the phylogenetic tree of these enzymes was undertaken in order to prove the evolutionary relationship between them. The mature trypsin PC and collagenolytic protease PC contain 237 (M calc 24.8 kDa) and 226 amino acid residues (M calc 23.5 kDa), respectively. Alignments of their amino acid sequences revealed a high degree of the trypsin PC identity to the trypsin from Penaeus vannamei (approximately 70%) and of the collagenolytic protease PC identity to the collagenase from fiddler crab Uca pugilator (76%). The phylogenetic tree of these enzymes was constructed. Primary structures of the two mature enzymes from P. camtschaticus were obtained and compared with those of other proteolytic proteins, including some enzymes from brachyurans. A phylogenetic analysis was also carried out. These comparisons revealed that brachyurins are closely related to their vertebrate and bacterial congeners, occupy an intermediate position between them, and their study significantly contributes to the understanding of the evolution and function of serine proteases.

Evidence for hormone-containing granules in sinus glands of the fiddler crab uca pugilator

Abstract: 1. Homogenates of sinus glands in isotonic sucrose cause little dispersion of black chromatophores when injected into legs or whole Uca. A liberation of hormone occurs when homogenates of sinus glands in isotonic sucrose are diluted in distilled water. A fraction, sedimentable by high speed centrifugation, when resuspended in distilled water and injected into the test animals, induces a dispersion of the chromatophores. These results support the view that the black chromatophore-dispersing hormone is contained within granules in sinus glands.2. The release of the hormone from the granules, obtainable by lowering the tonicity of the medium or by dilution in isotonic saline solutions, suggests that the granules possess a semipermeable membrane.3. The release of the hormone from the granules is increased by heating, by freezing and thawing, and by the action of detergents and digitonin.4. The black chromatophore-dispersing hormone may be a polypeptide, since it is inactivated by extracts of hepatopancreas an...

Recruitment to adult habitats following marine planktonic development in the fiddler crabs, Uca pugilator, U. pugnax, and U. minax

Abstract: Three congeneric species of fiddler crabs, Uca pugilator (Bosc, 1802), U. pugnax (Smith, 1870), and U. minax (LeConte, 1855), co-occur in estuaries along the east coast of North America, from Cape Cod to northern Florida. Although U. minax adults are generally found at lower salinities than the other two species, the distributions of all three species overlap to some degree. The distribution of megalopae and juvenile fiddler crabs (from first crab stage to those with a carapace width of 3.0 mm) was examined at four sites along a salinity gradient (from 35.0±2.0‰ to 3.0±3.0‰; \(\bar x\, \pm \,{\text{SD}} \) ) in the North Inlet Estuary, South Carolina, USA, in August 2002. A PCR-RFLP technique was developed to identify individuals from the genus Uca to species from first zoea through the early crab stages. An examination of the distribution of early life stages showed that U. minax reinvades low-salinity adult habitats at settlement, following planktonic larval development in the coastal ocean. Also, juveniles of U. pugilator were found to occupy Spartina alterniflora stands, where adult conspecifics rarely occur. Species frequencies were different for adults compared to early life stages in low-salinity areas of the marsh, where populations overlap. Settlement and survival dynamics of early life-history stages in wet and dry years likely determine the distribution of adult Uca spp. populations along salinity gradients in estuarine ecosystems.

Pinching forces in crayfish and fiddler crabs, and comparisons with the closing forces of other animals

Abstract: The pinching forces of crustaceans are in many respects analogous to the biting forces of vertebrates. We examined the effects of body size and chelae size and shape, on the closing forces of the fiddler crab, Uca pugilator, and the crayfish, Procambarus clarkii. We hypothesized that the allometric relationships would be similar among species, and comparable to those reported for other decapod crustaceans. We further hypothesized that the scaling of the closing forces of crustaceans, with respect to body size and with the geometry of the pinching or biting structures, would be similar to that of vertebrates. We found that pinching forces increased with body mass, claw dimensions, and claw mass in U. pugilator, but only with claw height and claw mass in P. clarkii. Contraction time increased with body mass for both species combined, whereas contraction speed decreased. Pooled data for these and 17 other species of decapod crustacean revealed a positive correlation between the pinching force and body mass with a scaling exponent of 0.71. These data are remarkably comparable to the values on closing forces of vertebrate jaws, with the pooled data having a scaling exponent of 0.58, slightly below the value of 0.67 predicted for geometric similarity. Maximum closing forces vary tremendously among both crustaceans and animals in general, with body size and food habits being among the most important determining factors.