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PubMed1994

Purification and characterization of a cadmium-induced metallothionein from the shore crab Carcinus maenas (L.).

Two metallothionein variants were purified from the midgut gland of crabs (Carcinus maenas) exposed to a high cadmium concentration (2 p.p.m.). One of the variants was purified from crabs exposed to a low cadmium concentration (0.5 p.p.m.). The purification method involved acetone precipitation, gel filtration and reversed-phase h.p.l.c. The complete amino acid sequences of both variants have been elucidated by m.s. and automated sequence analysis on S-methylated proteins or fragments produced by cleavage of the S-methylated proteins with Staphylococcus aureus proteinase. The two variants from crabs exposed to the high cadmium concentration differed only by a single residue of methionine at the N-terminus. The single variant isolated from crabs exposed to the low cadmium concentration was the one without the N-terminal methionine, indicating that high cadmium concentrations either inhibit the processing enzymes and/or that the processing enzymes cannot keep pace with the increased metallothionein synthesis when cadmium availability is high. Cadmium-induced metallothionein from C. maenas shows a high degree of structural similarity to metallothioneins from the decapod crustaceans Scylla serrata and Homarus americanus.

Amino Acid Sequence↗
PubMed2002

Mitochondrial gene rearrangements confirm the parallel evolution of the crab-like form.

The repeated appearance of strikingly similar crab-like forms in independent decapod crustacean lineages represents a remarkable case of parallel evolution. Uncertainty surrounding the phylogenetic relationships among crab-like lineages has hampered evolutionary studies. As is often the case, aligned DNA sequences by themselves were unable to fully resolve these relationships. Four nested mitochondrial gene rearrangements--including one of the few reported movements of an arthropod protein-coding gene--are congruent with the DNA phylogeny and help to resolve a crucial node. A phylogenetic analysis of DNA sequences, and gene rearrangements, supported five independent origins of the crab-like form, and suggests that the evolution of the crab-like form may be irreversible. This result supports the utility of mitochondrial gene rearrangements in phylogenetic reconstruction.

Amino Acid Sequence↗
PubMed2006

Cross-reactivity among shrimp, crab and scallops in a patient with a seafood allergy.

Shrimp is known to be the most common causative agent in seafood allergy. Patients with shrimp allergy often exhibit allergic symptoms to a variety of seafoods such as crabs and clams. We experienced a 14-year-old girl with shrimp allergy who developed oral swelling and pain accompanied with an uncomfortable feeling after ingestion of scallops followed by intensive exercise. Laboratory investigation showed that she had serum immunoglobulin (Ig)E molecules reacting with several kinds of crustaceans and mollusks, including shrimp, crab and scallops. Immunoblotting revealed that her serum IgE reacted with the 38 kDa bands for shrimp, crab and scallops, suggesting that tropomyosin was the major allergen. Dot-blot inhibition analysis showed a cross-reactivity among shrimp, crab and scallops. We conclude that the cross-reactivity of IgE in this patient resulted from the high homology of tropomyosins.

Adolescent↗
PubMed1993

Superpotent synthetic tripeptide mimics of the mud-crab pumping pheromone.

Soluble pheromones released by the mud crab, Rhithropanopeus harrisii (Gould) during egg hatching cause the female crab to contract her abdomen rapidly (the pumping response). This stereotypical behavior can be induced in the laboratory by exposing egg-bearing females to solutions containing certain amino acids or peptides. Twelve amino acids exhibited response thresholds of 10(-3)-10(-10) M, the most potent (norleucine, methionine and tryptophan) having a hydrophobic sidechain. Four synthetic tripeptides of the form Gly-X-Arg, where the hydrophobic residue X was isoleucine, norleucine, methionine or phenylalanine, were superpotent agonists over a limited concentration range. Gly-Ile-Arg was a significant agonist at 10(-17) and 10(-16) M, both Gly-Nle-Arg and Gly-Met-Arg at 10(-20) and 10(-19) M, and Gly-Phe-Arg at 10(-21), 10(-20) and 10(-19) M. At the subattomolar concentration of 10(-20) M the superpotent pheromone mimics Gly-Met-Arg and Gly-Phe-Arg produced not only a statistically significant increase in the relative number of pumping mud crabs but also a substantial increase in the pumping rate ratio. In contrast, at 10(-13) M the tripeptide Gly-Met(O)-Arg with an internal residue of methionine sulfoxide blocked the abdominal pumping response of egg-bearing mud crabs.

Amino Acid Sequence↗
PubMed1997

Isolation and identification of multiple neuropeptides of the allatostatin superfamily in the shore crab Carcinus maenas.

20 neuropeptides belonging to the allatostatin superfamily were isolated from extracts of cerebral and thoracic ganglia of the shore crab Carcinus maenas. They were purified by HPLC, monitored by radioimmunoassay and identified by mass spectrometry and amino acid sequencing. The allatostatins are characterised by a common C-terminal pentapeptide sequence -YXFGL-NH2. Previously such peptides have only been reported from insects. In insects the variable post-tyrosyl residue is restricted to Ala, Asn, Asp, Gly or Ser. In C. maenas, however, there are only two types; thirteen of the peptides having a post-tyrosyl Ala and the other seven, a post-tyrosyl Ser. The crab peptides include the shortest allatostatins so far identified (YAFGL-NH2 and YSFGL-NH2) as well as the longest, a 27-residue peptide. The total of 20 peptides exceeds the highest number of allatostatins found in any of the insects investigated so far (14 in Periplaneta americana). It is of interest that, despite their clear homology, none of the peptides of C. maenas is identical to any of the more than 50 known insect allatostatins. The crab allatostatins show evidence of gene duplication and mutation that has resulted in several sub-groups with close structural similarities. For example, there are four heptapeptides with the common C-terminus -PYAFGL-NH2 that differ only at the N-terminal residue, which is either Glu, Asp, Asn or Ser. Other motifs, variously extended at the N-terminus, include -GPY(A/S)FGL-NH2 (three peptides), -DMY(A/S)FGL-NH2 (three peptides), and -GQY(A/S)FGL-NH2 (two peptides). Unique among the allatostatin superfamily, one of the crab peptides has a Tyr for Phe substitution at position three from the C-terminus (GGPYSYGL-NH2). Immunocytochemistry has provided clues to the functions of the allatostatins in crustaceans by showing their widespread presence in the central and stomatogastric nervous systems.

Amino Acid Sequence↗
PubMed1986

Colonization of the gut of the blue crab (Callinectes sapidus) by Vibrio cholerae.

Attachment of Vibrio cholerae to the mucosal surface of the intestine is considered to be an important virulence characteristic. Vibrio cholerae, an autochthonous member of brackish water and estuarine bacterial communities, also attaches to crustacea, a significant factor in multiplication and survival of V. cholerae in nature. The ability of V. cholerae to attach to the gut wall of the blue crab (Callinectes sapidus) was examined, and attachment was observed only in the hindgut and not the midgut of crabs, confirming a requirement for chitin in the attachment of V. cholerae to invertebrate and zooplankton surfaces. The new finding of attachment of V. cholerae to the hindgut of crabs may be correlated with the epidemiology and transmission of cholera in the aquatic environment. The crab model may also prove useful in elucidating the mechanism(s) of ion transport in crustacea.

Animals↗
PubMed1992

Bdellovibrios in Callinectus sapidus, the Blue Crab.

Bdellovibrios were recovered from the gill tissue of all of 31 crabs sampled and from all samples of epibiota obtained from the ventral shell surface of 15 crabs. The results suggest that the blue crab is a reservoir for bdellovibrios. The association with crabs may be an important factor in the ecology of the bdellovibrios.

Journal Article↗
PubMed1965

Characteristics of yeasts isolated from Pacific crab meat.

A total of 202 cultures of yeasts were isolated and characterized from king crab and Dungeness crab meat. A yeastlike organism, resembling Aureobasidium pullulans, and 15 different species distributed among the genera Rhodotorula, Cryptococcus, Torulopsis, Candida, and Trichosporon were represented. Nine of the species grew at 5 C or lower. Although two of the species grew at 37 C, none of the isolates had the characteristics of pathogenic species. Members of the Cryptococcus and Candida failed to grow at 37 C. Furthermore, species of the former genus were not pathogenic to mice. The pigmentation of the Rhodotorula cultures decreased in intensity as the incubation temperature was decreased. Biochemical activities of the different species were studied by use of triglycerides, lecithin, and proteins (casein, gelatin, and crab-meat protein) as substrates. Eight of the species could attack triglycerides; eight, lecithin; five, gelatin; one, casein; and one, crab protein. An organism, tentatively identified as Trichosporon sp., was very active in attacking each of the substrates tested and grew well at 0.5 C.

Candida↗
PubMed1972

Bacteriological survey of the blue crab industry.

During sanitation inspections of 46 crabmeat processing plants on the Atlantic and Gulf Coasts, 487 samples of whole crabs immediately after cooking, cooked crabs after cooling, backed or washed (or both) crab bodies and whole crab claws, as well as 1,506 retail units of finished product were collected and analyzed bacteriologically. The 1,506 retail units (1-lb [373.24-g] cans) included 518 cans of regular (special) meat, 487 cans of claw meat, and 501 cans of lump meat. Statistical analyses showed that crabmeat from plants in Mississippi, Louisiana, and Texas had higher counts in 19 of 24 cases for the four bacteriological indices than crabmeat from plants located along the Atlantic Coast and the Gulf Coast of Florida. Aerobic plate counts of retail units collected from a previous day's production were significantly higher than those collected on the day of inspection. Regular crabmeat had consistently higher aerobic plate counts than claw or lump meat. When the product was handled expeditiously under good sanitary conditions, the bacteriological results were significantly better than the results from plants operating under poor sanitary conditions. Crabmeat produced in plants operating under good sanitary conditions had the following bacteriological content: (i) coliform organisms average most-probable-number values (geometric) of less than 20 per g; (ii) no Escherichia coli; (iii) coagulase-positive staphylococci average most-probable-number values (geometric) of less than 30 per g in 93% of the plants; (iv) aerobic plate count average values (geometric) of less than 100,000 per g in 93% of the plants, with the counts from 85% of these plants below 50,000 per g.

Aerobiosis↗
PubMed1981

Amiloride-sensitive ammonium and sodium ion transport in the blue crab.

In the estuarine crab, Callinectes sapidus, net NH4+ efflux was twice as high in animals acclimated to 17% salinity seawater (SW) (0.495 +/- 0.084 mumol . h-1 . g wet wt-1, n = 7) than in animals acclimated to full-strength 35% SW (0.212 +/- 0.028 mumol . h-1 . g-1, n = 7). Amiloride (3 X 10(-4) M) in the external SW reversibly inhibited these effluxes by 63 +/- 6% (n = 6) and 67 +/- 6% (n = 5), respectively. Unidirectional Na+ influx was reversibly inhibited 42 +/- 6% (n = 7) by amiloride in 17% SW-acclimated crabs and 49 +/- 7% (n = 8) in 35% SW-acclimated crabs. This mutual sensitivity to amiloride is evidence for a Na+/NH4+ exchanger. Inhibition of unidirectional Na+ efflux by Na+-free SW indicates the presence of an obligate Na+/Na+ exchange component that accounts for at least 42% of the Na+ flux and is also amiloride sensitive. The lack of inhibition by amiloride of the net H+ efflux does not support the presence of a Na+/H+ exchanger. Acclimation of the crab to dilute SW may involve an increase in the activity of the Na+/NH4+ exchanger in the gills, but this mechanism contributes only a small fraction of the total Na+ transport.

Acclimatization↗
PubMed1983

Aerobic response to exercise of the fastest land crab.

To view the aerobic response to exercise, the ghost crab Ocypode guadichaudii was run in a treadmill respirometer at three velocities (0.13, 0.19, and 0.28 km/h) while oxygen consumption (VO2) was monitored. A steady-state VO2 that increased linearly with velocity was attained. VO2 transient periods at the beginning and end of exercise were extremely rapid with half times from 50 to 150 s. The magnitude of oxygen deficit and debt were small and both showed increases with an increase in velocity. Oxygen debt was measured at each velocity after 4-, 10-, and 20-min exercise bouts. No change in the magnitude of oxygen debt was observed with respect to exercise duration. Maximal VO2 was 11.9 times the average resting VO2. Oxygen uptake kinetics have shown only very sluggish and reduced rates in five other more sedentary crab species previously tested. The aerobic response pattern observed in the present study is more comparable to that of exercising mammals and highly aerobic ectothermic vertebrates. This suggests that the ghost crab meets the energy demand of sustained exercise by aerobic ATP production in contrast to many other crab species.

Aerobiosis↗
PubMed2004

Ontogeny of osmoregulatory structures and functions in the green crab Carcinus maenas (Crustacea, Decapoda).

The ontogeny of osmoregulation, the development of branchial transporting epithelia and the expression of the enzyme Na+/K+-ATPase were studied in Carcinus maenas (L.) obtained from the North Sea, Germany. Laboratory-reared zoea larvae, megalopae and young crabs were exposed to a wide range of salinities, and hemolymph osmolality was measured after 24 h exposure time (72 h in juveniles). Zoea I larvae slightly hyper-regulated in dilute media (10.2 per thousand and 17.0 per thousand ) and osmoconformed at >17 per thousand. All later zoeal stages (II-IV) osmoconformed in salinities from 10.2 per thousand to 44.3 per thousand. The megalopa hyper-regulated at salinities from 10.2 to 25.5 per thousand. Young crabs hyperregulated at salinities from 5.3 per thousand to 25.5 per thousand, showing an increase in their osmoregulatory capacity. The development of transporting epithelia and the expression of Na+/K+-ATPase were investigated by means of transmission electron microscopy and immunofluorescence microscopy. In the zoea IV, only a very light fluorescence staining was observed in gill buds. Epithelial cells were rather undifferentiated, without showing any features of ionocytes. Gills were present in the megalopa, where Na+/K+-ATPase was located in basal filaments of the posterior gills. In crab I juveniles and adults, Na+/K+-ATPase was noted in the three most posterior pairs of gills, but lacking in anterior gills. Ionocytes could first be recognized in filaments of megalopal posterior gills, persisting through subsequent stages at the same location. Thus, the development of the gills and the expression of Na+/K+-ATPase are closely correlated with the ontogeny of osmoregulatory abilities. The morphological two-step metamorphosis of C. maenas can also be regarded as an osmo-physiological metamorphosis, (i) from the osmoconforming zoeal stages to the weakly regulating megalopa, and (ii) to the effectively hyper-regulating juvenile and adult crabs.

Animals↗
PubMed2004

Ammonia excretion in aquatic and terrestrial crabs.

The excretory transport of toxic ammonia across epithelia is not fully understood. This review presents data combined with models of ammonia excretion derived from studies on decapod crabs, with a view to providing new impetus to investigation of this essential issue. The majority of crabs preserve ammonotely regardless of their habitat, which varies from extreme hypersaline to freshwater aquatic environments, and ranges from transient air exposure to obligate air breathing. Important components in the excretory process are the Na+/K+(NH4+)-ATPase and other membrane-bound transport proteins identified in many species, an exocytotic ammonia excretion mechanism thought to function in gills of aquatic crabs such as Carcinus maenas, and gaseous ammonia release found in terrestrial crabs, such as Geograpsus grayi and Ocypode quadrata. In addition, this review presents evidence for a crustacean Rhesus-like protein that shows high homology to the human Rhesus-like ammonia transporter both in its amino acid sequence and in its predicted secondary structure.

Ammonia↗
PubMed2004

Ion-motive ATPases and active, transbranchial NaCl uptake in the red freshwater crab, Dilocarcinus pagei (Decapoda, Trichodactylidae).

The present investigation examined the microanatomy and mRNA expression and activity of ion-motive ATPases, in anterior and posterior gills of a South American, true freshwater crab, Dilocarcinus pagei. Like diadromous crabs, the anterior gills of this hololimnetic trichodactylid exhibit a highly attenuated (2-5 microm), symmetrical epithelium on both lamellar surfaces. In sharp contrast, the posterior gill lamellar epithelia are markedly asymmetrical. Their proximal side consists of thick (18-20 microm) cells, displaying features typical of a transporting epithelium, while the distal epithelium is thin (3-10 microm) and formed entirely by apical pillar cell flanges. Both anterior and posterior gills express Na+/K+- and V-ATPases. Phylogenetic analysis of partial cDNA sequences for the Na+/K+-ATPase alpha-subunit and V-ATPase B-subunit among various crab species confirmed the previous classification and grouping of D. pagei based on morphological criteria. Semi-quantitative RT-PCR clearly showed that mRNA for both ion pump subunits is more intensely expressed in posterior gills. Na+/K+-ATPase activity in the posterior gills was nearly fourfold that of anterior gills, while V-ATPase and F-ATPase activities did not differ. A negative short-circuit current (Isc) was measured using the distal side of split, posterior gill lamellae, mounted in a modified Ussing chamber and perfused symmetrically with identical hemolymph-like salines. Although hemolymph-side ouabain did not affect this current, concanamycin significantly reduced Isc without altering preparation conductance, suggesting V-ATPase-driven Cl- absorption on the distal side of the posterior gill lamellae, as known to occur in diadromous crabs adapted to freshwater. These findings suggest that active Na+ uptake predominates across the thick proximal epithelium, and Cl- uptake across the thin, distal epithelium of the posterior gill lamellae.

Amino Acid Sequence↗
PubMed2006

Feeding and digestion in low salinity in an osmoconforming crab, Cancer gracilis. II. Gastric evacuation and motility.

Gastric evacuation and gut contraction rates were followed in the graceful crab Cancer gracilis during exposure to low salinity. Crabs were fed a radio-opaque meal and then exposed to 100% seawater (SW), 80%SW or 60%SW; passage of digesta was followed using a fluoroscope. Exposure to low salinity increased the time for food passage through the gut system. Times for emptying of the foregut, midgut and hindgut varied in a dose-dependent manner. In the lowest salinity, crabs regurgitated food from the foregut after approximately 6 h. This may act as a protective response, clearing the gut and avoiding subsequent increases in metabolism associated with digestion. Contraction rate of the cardiac stomach and gastric mill was sporadic and there was no significant change with salinity. In contrast, contractions of the pyloric region were more constant and rapid. Pyloric contractions decreased at each salinity within 2-4 h after feeding. Contraction rates of the pyloric chamber were significantly lower in 60%SW compared with 100%SW and 80%SW. During a salinity cycle there was also slowing of gut contractions and food passage through the gut system. Pre-treatment levels were only regained slowly when the animals were returned to 100%SW. Cancer gracilis was able to slow digestion during low salinity exposure, which may spare resources for other systems. However, the crabs could not halt digestion completely and may be committed to protein synthesis once intracellular digestion has begun.

Acclimatization↗
PubMed1994

EFFECT OF THE EXTERNAL CONCENTRATION OF CALCIUM ON THE POSTMOULT UPTAKE OF CALCIUM IN BLUE CRABS (CALLINECTES SAPIDUS)

The rate of calcium uptake in blue crabs (Callinectes sapidus Rathbun) acclimated to 2 sea water with a calcium concentration of 1.4 mmol l-1 was dependent on the magnitude and direction of the electrochemical gradient for calcium. When transferred to water with a high calcium concentration (6 mmol l-1), the electrochemical gradient for calcium favoured diffusive influx, and calcium uptake and apparent H+ excretion increased by approximately 50 %. When transferred to water with a low calcium concentration (0.10 mmol l-1), where the electrochemical gradient for calcium strongly favoured diffusive efflux, calcium uptake ceased but apparent H+ excretion continued at a reduced rate. Crabs regulated the free calcium concentration in their blood at approximately 8 mmol l-1 when the external concentration of calcium was 1.4 mmol l-1 or higher, but the concentration of free calcium in the blood decreased to 5.6 and 4.6 mmol l-1, respectively, at external concentrations of calcium of 0.25 and 0.10 mmol l-1. Crabs transferred to water with 0.10 mmol l-1 calcium for the first 2 days after moult accumulated only 2.5 g calcium kg-1 wet mass, about one-quarter of the mass normally accumulated. Seawater-acclimated crabs transferred to 2 salinity at 1 day postmoult took up calcium at a reduced rate, indicating that a period of acclimation is necessary for a component of the active transport system to increase its capacity, for diffusive efflux to be reduced, or for both to occur.

Journal Article↗
PubMed1996

Adaptation to temperature stress and aerial exposure in congeneric species of intertidal porcelain crabs (genus Petrolisthes): correlation of physiology, biochemistry and morphology with vertical distribution

We examined physiological and biochemical responses to temperature and aerial exposure in two species of intertidal porcelain crabs (genus Petrolisthes) that inhabit discrete vertical zones. On the shores of the Northeastern Pacific, P. cinctipes (Randall) occurs under rocks and in mussel beds in the mid to high intertidal zone and P. eriomerus (Stimpson) occurs under rocks in the low intertidal zone and subtidally to 80 m. Because of their different vertical distributions, these two species experience very different levels of abiotic stress. Individuals of P. cinctipes can be emersed during every low tide, but P. eriomerus is only emersed during the lowest spring tides and on most days is not emersed at all. Temperatures measured underneath rocks in the mid intertidal zone were as high as 31 °C, 15 °C higher than maximal temperatures measured under rocks in the low intertidal zone. In air, at 25 °C, large specimens of P. cinctipes were able to maintain a higher respiration rate than similarly sized P. eriomerus. No interspecific differences in the respiratory response to emersion were seen in small specimens. Examination of the response of heart rate to temperature revealed that P. cinctipes has a 5 °C higher Arrhenius break temperature (ABT, the temperature at which there is a discontinuity in the slope of an Arrhenius plot) than its congener (31.5 °C versus 26.6 °C). The heart rate of P. cinctipes recovered fully after exposure to cold (1.5 °C), but the heart rate of P. eriomerus did not recover after exposure to 2 °C or cooler. The ABT of heart rate in P. cinctipes was very close to maximal microhabitat temperatures; thus, individuals of this species may be living at or near their thermal tolerance limits. P. cinctipes were able to maintain aerobic metabolism during emersion, whereas P. eriomerus shifted to anaerobic metabolism. A pronounced accumulation of whole-body lactate was found in specimens of P. eriomerus incubated in air at 25 °C over a 5 h period, but not in P. cinctipes similarly treated. P. cinctipes possesses a membranous structure on the ventral merus of each walking leg, but this structure is not found in P. eriomerus. To test the function of the leg membrane, we measured the aerial respiration rates and the lactate accumulation of P. cinctipes with their leg membranes obscured. These individuals had significantly lower aerial respiration rates at 30 °C than control crabs. Crabs with leg membranes obscured also accumulated a considerable amount of lactate during a 5 h period of emersion at 28 °C, but control crabs showed no accumulation under the same conditions. These data suggest that the leg membrane functions as a respiratory structure. The results of this study illustrate that a suite of morphological, physiological and biochemical features allows P. cinctipes to live higher in the intertidal region than P. eriomerus.

Journal Article↗
PubMed1997

Two novel tachykinin-related peptides from the nervous system of the crab Cancer borealis.

Immunocytochemical and biochemical studies have indicated the presence of many neuroactive substances in the stomatogastric nervous system (STNS) of the crab Cancer borealis. In electrophysiological studies, many of these substances modulate the motor output of neural networks contained within this system. Previous work in the STNS suggested the presence of neuropeptides related to the invertebrate tachykinin-related peptide (TRP) family. Here we isolate and characterize two novel peptides from the C. borealis nervous system that show strong amino acid sequence identity to the invertebrate TRPs. The central nervous systems of 160 crabs were extracted in an acidified solvent, after which four reversed-phase HPLC column systems were used to obtain pure peptides. A cockroach hindgut muscle contraction bioassay and a radioimmunoassay (RIA) employing an antiserum to locustatachykinin I (Lom TK I) were used to monitor all collected fractions. The amino acid sequences of the isolated peptides were determined by Edman degradation. Mass spectrometry and chemical synthesis confirmed the sequences to be APSGFLGMR-NH2 and SGFLGMR-NH2. APSGFLGMR-NH2 is approximately 20-fold more abundant in the crab central nervous system than is SGFLGMR-NH2. We have named these peptides Cancer borealis tachykinin-related peptide Ia and Ib (CabTRP Ia and Ib), respectively. Both peptides are myoactive in the cockroach hindgut muscle contraction bioassay, with CabTRP Ia being approximately 500 times more potent than CabTRP Ib. RIA performed on HPLC-separated C. borealis stomatogastric ganglion (STG) extract revealed that CabTRP Ia is the only detectable TRP-like moiety in this ganglion. Incubation of synthetic CabTRP Ia with the isolated STG excited the pyloric motor pattern. These effects were suppressed by the broad-spectrum tachykinin receptor antagonist Spantide I. Spantide I had no effect on the actions of the unrelated endogenous peptide proctolin in the STG. There was no consistent influence of CabTRP Ib on the pyloric rhythm. Given its amino acid sequence and minimal biological activity in the crab, CabTRP Ib may be a breakdown product of CabTRP Ia.

Amino Acid Sequence↗