A comparative study of the digestive enzymes in the hepatopancreas of Jonah crab (Cancer borealis) and rock crab (Cancer irroratus)

A pair of rock crabs, Cancer irroratus, in mating embrace an hour after being placed in a laboratory tank, was observed intermittently until ecdysis of the female and copulation of the pair, and then until escape of the female 27 d after ecdysis. When separated from the mating embrace, the hard-shelled female sought out the male. Approach of female ecdysis was indicated by protrusion of a soft spherical bulge at the rear of the epimeral line. Details of the immediate pre- and postcopulatory behavior were observed continuously from 26 min before to 150 min after copulation. The female was first noted separated from the male 7 h after copulation. Periods of separation increased until mating interactions were completely abandoned 5 d after copulation. A second pair subsequently observed confirmed the above. Mating embrace was also observed between a hard-shelled male and a hard-shelled female that already had sperm plugs. Key words: Crustacea, crabs, copulation, molt indicators

Download Full-text

The Pharmacological Profile of the Acetylcholine Response of a Crustacean Muscle

Journal of Experimental Biology ◽

10.1242/jeb.88.1.147 ◽

1980 ◽

Vol 88 (1) ◽

pp. 147-160

Author(s):

EVE MARDER ◽

DANIÈLE PAUPARDIN-TRITSCH

Keyword(s):

Acetylcholinesterase Activity ◽

Gastric Mill ◽

Muscarinic Agonists ◽

Pharmacological Profile ◽

Cancer Borealis ◽

Cancer Irroratus ◽

Pharmacological Analysis ◽

Crustacean Muscle ◽

Cancer Pagurus ◽

High Concentrations

A pharmacological analysis was made of the depolarizing acetylcholine (ACh) response found on the gastric mill 1 muscles of the crabs Cancer pagurus, Cancer irroratus and Cancer borealis. Acetylcholine, carbamylcholine, trimethylammonium, nicotine, and dimethyl-4-phenyl-piperazinium were effective in producing contractures and depolarizations in these muscles. No response to decamethonium, suberyldicholine, acetyl-β-methylcholine, carbamyl-β-methylcholine, pilocarpine and oxotremorine could be detected. High concentrations of muscarinic agonists (10−4 to 10−3 M) potentiated and prolonged the ACh iontophoretic response. When the acetylcholinesterase activity was inhibited with neostigmine, or when the response was elicited with carbamylcholine, muscarinic agonists partially inhibited the response. ACh responses were most effectively blocked by vertebrate nicotinic ganglionic antagonists, including dihydro-β-erythroidine, pempidine, and mecamylamine. α-Bungarotoxin was without effect on the ACh response.

Download Full-text

Organic cation secretion by Cancer borealis urinary bladder

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1987.252.1.r153 ◽

1987 ◽

Vol 252 (1) ◽

pp. R153-R159 ◽

Cited By ~ 1

Author(s):

D. S. Miller ◽

C. W. Holliday

Keyword(s):

Polyethylene Glycol ◽

Urinary Bladder ◽

Secretory Pathway ◽

Organic Cation ◽

Homarus Americanus ◽

Cancer Borealis ◽

Cancer Irroratus ◽

Clearance Studies ◽

Secretory Transport ◽

Initial Clearance

In the crab, Cancer borealis, initial clearance studies showed a potent renal excretory system for the model organic cation, tetraethylammonium (TEA). TEA clearance averaged 145 +/- 32 ml/day, which was 18 times the paired polyethylene glycol clearance. TEA uptake by slices of urinary bladder was concentrative, saturable, inhibitable by N1-methylnicotinamide chloride, and dependent on glycolytic, but not oxidative, metabolism. When mounted in flux chambers, bladders exhibited a large net secretory flux. For 0.1 mM TEA, the ratio of secretory to reabsorptive fluxes was 65. Urinary bladders from another crab, Cancer irroratus, and a lobster, Homarus americanus, also exhibited net TEA secretion. In C. borealis bladder, secretory transport was concentrative, saturable, and nearly abolished by addition of 1 mM quinine to the serosal bath. Reabsorptive transport was not concentrative and was not reduced by luminal quinine. The data are consistent with a secretory pathway that is transcellular and mediated by carriers at both the serosal and luminal membranes.

Download Full-text