Uca pugilator

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

Isolation and characterization of sinus gland neuropeptides with both mandibular organ inhibiting and hyperglycemic effects from the spider crab Libinia emarginata

Abstract: Using two-step reverse phase HPLC, we isolated and purified three peptides with mandibular organ inhibiting hormone (MO-IH) activity from the spider crab Libinia emarginata. One of the peptides, P22, gave a yield of 355 ng/SG. The others gave lower yields: P21, 9 ng/SG; P25, 67.5 ng/SG. The molecular weight was determined to be 8,439 for P25, 8,474 for P22, and 8,398 for P21 by mass spectrometry. All three peptides have similar amino acid compositions and contain 72–76 residues. We believe these peptides to be different isoforms of one family. The MO is more sensitive to the two minor isoforms, P21 and P25. All three isoforms can inhibit MO activity to a maximum inhibition of 70%. All three isoforms gave a significant hyperglycemic effect when injected into de-eyestalked fiddler crabs Uca pugilator. We believe the MO-IHs to be members of the crustacean hyperglycemic hormone (CHH) family, having similar amino acid compositions and both biological activities. © 1996 Wiley-Liss, Inc.

Amino acid sequence of a collagenolytic protease from the hepatopancreas of the fiddler crab, Uca pugilator

Abstract: The amino acid sequence of a collagenolytic protease from the hepatopancreas of the fiddler crab, Uca pugilator, was determined from the structures of overlapping tryptic, chymotryptic, thermolytic, staphylococcal protease, and cyanogen bromide peptides together with automated sequencer analysis of the intact protein. Crab collagenase is a serine protease composed of 226 residues which is capable of degrading the native triple helix of collagen under physiological conditions. When aligned for optimal homology, crab collagenase displays 35% identity with bovine trypsin, 38% with bovine chymotrypsin B, and 32% with porcine elastase. The six half-cystinyl residues in crab collagenase correspond to those forming three of the five disulfide bonds in chymotrypsin. The residues forming the charge relay system of the active site of chymotrypsin (His-57, Asp-102, and Ser-195) are found in corresponding regions in crab collagenase, and the sequences around these residues are well conserved. The primary structure of crab collagenase is the first reported for a serine protease from crustacean hepatopancreas and the first reported for a serine protease possessing the unusual property of being able to degrade native helical collagen.

Flexibility in timing of the metamorphic molt by fiddler crab megalopae Uca pugilator

Abstract: The larvae of many invertebrate taxa can delay metamorphosis for considerable periods of time in the absence of specific stimuli for settlement. This study tested the hypothesis that the duration of the megalopal stage of fiddler crabs can be adjusted by several days depending on the availability of some habitat components. The hypothesis that megalopae can delay the metamorphic molt was tested by comparing the proportion of individuals molting to the first crab instar in aquaria containing only filtered seawater to that in aquaria with mud, sand, and/or an adult crab, near the predicted time of molting. The hypothesis that molting can be advanced was tested by comparing the proportion of sibling larvae molting at intervals throughout the megalopal stage in aquaria containing only filtered seawater or seawater plus an adult crab, mud, and sand. Megalopae delayed molting unless 2 stimuli were present: an adult crab and sediment, either mud or sand. The metamorphic molt was advanced in the presence of both these cues, although contact with the sediment by the adult crab appears necessary for maximal effect. Flexibility in timing of molting and the requirement for more than one cue can increase the chance that megalopae settle and molt to the first crab instar in appropriate adult habitats.

Growth and regeneration patterns in the fiddler crab, uca pugilator

Abstract: The fiddler crab, Uca pugilator, will survive several intermolt cycles in the laboratory, but the cycles are irregular. Variations in cycles are due to variations in the length of stage C4. The transition from C4 to D in intact crabs does not seem to be due to environmental clues because crabs kept in constant conditions for long periods of time continue to have extremely variable intermolt cycles.Multiple autotomy triggers the onset of proecdysis and a post-autotomy intermolt cycle that is significantly shorter than controls. Multiple autotomy-induced proecdysis is divided into two phases: the "reset event" is independent of the eyestalks, while the "proecdysial program" is normally under their control. Loss of a cheliped is more effective in initiating a reset event than is loss of a single walking leg.Eyestalk removal forces crabs into proecdysis. If crabs are in early proecdysis (stage D0) at eyestalk removal, the proecdysial period is accelerated. Eyestalk removal results in large increases in size a...