The early phyllosoma stages of spiny lobster Panulirus echinatus Smith, 1869 (Decapoda: Palinuridae) reared in the laboratory.

The early stages of the Panulirus echinatus were hatched and reared in the laboratory. Ovigerous females were captured in their habitat and carefully transported to the laboratory. Larvae were transferred in a recirculation water tank at a density of 10 larvae.L(-1). The larvae were fed on Artemia and gonads of mussel Brachydonts sp. Microalgae Dunaliella viridis was added at a concentration of 150 x 10(4) cell.mL(-1). Larvae and exuviae of each zoeal stage were preserved in an alcohol 70% + glycerin (1:1) solution. The phyllosomas moulted eight times; the intermoulting period of each instar averaged about 7 to 10 days. The main morphological changes of each appendage were described in detail, illustrated and compared with previous reports.     

Mouthpart and foregut ontogeny in larval, postlarval, and juvenile spiny lobster, Panulirus argus Latreille (Decapoda, Palinuridae)

The spiny lobster Panulirus argus has a life cycle consisting of a long-term (～9-12 months) planktonic larval period with 11 larval stages (the phyllosoma), a short (<1 month?) planktonic-to-benthic transitional postlarval stage (the puerulus), and benthic juvenile and adult phases. The mouthparts and foregut during these stages were examined and described by means of scanning electron microscopy (SEM) in an investigation of the species' developmental morphology, diet, and ecology. The phyllosoma mouthparts close to the esophagus are the labrum, mandibles, paragnaths, and first maxillae. The second maxillae and first and second maxillipeds are increasingly distant from the esophagus as the larva develops. The pair of asymmetrical mandibles bear many teeth and spines, and the molar processes form what appears to be an intricate toothed shear. The mandibles remain similar throughout the phyllosoma stages. During the molt into the puerulus, the mouthparts are greatly changed, and the second maxilla and the three maxillipeds join the other mouthparts near the esophagus. However, the transformation appears incomplete, and many of the mouthparts are not fully formed until the molt to juvenile completes their development. The phyllosoma foregut lacks a gastric mill and has but one chamber. In addition, the first two stages lack a gland filter. During the molt to puerulus, the foregut is greatly changed and subsequently is similar to typical decapod foreguts in having an anterior cardiac and posterior pyloric chamber. Only rudimentary internal armature is present. Following the molt to juvenile, the foregut is quite similar to that of the adult, which exhibits a substantial gastric mill. The 11 phyllosoma stages were separated into two groups (group A = stages 1-5, group B = stages 6-11) on the basis of changes in both mouthpart and foregut morphology. The puerulus has never been observed to feed. Nothing was observed in our investigations that would prevent feeding, though both mouthpart and foregut development appeared incomplete. The mouthpart and foregut structures of larval, postlarval and juvenile P. argus differ widely, possibly reflecting the extreme modifications for different habitats found among these life phases.     

Behavioral thermoregulation in the spiny lobster Panulirus Argus (latreille)

Ten spiny lobsters (Panulirus argus) were allowed to thermoregulate individually for 3-day periods in an electronic thermoregulatory shuttlebox which allowed them to control water temperatures (and thereby their own body temperatures) by their movements. The range of preferred (voluntarily occupied) temperatures was 25–35°C (mean 29.9°C; mode 30.0°C; median 30.0°C; midpoint 30.0°C; S_k (skewness, Pearson's coefficient) –0.04; s.e.m. 0.19°C; S.D. 2.32°C). The final thermal preferendum (by the gravitation method) in this species is 30°C.     

Hemocyanin-derived phenoloxidase activity in the spiny lobster Panulirus argus (Latreille, 1804)

Hemocyanin and phenoloxidase belong to the type-3 copper protein family, sharing a similar active center whereas performing different roles. In this study, we demonstrated that purified hemocyanin (450 kDa) from the spiny lobster Panulirus argus shows phenoloxidase activity in vitro after treatment with trypsin, chymotrypsin and SDS (0.1% optimal concentration), but it is not activated by sodium perchlorate or isopropanol. The optimal pHs of the SDS-activated hemocyanin were 5.5 and 7.0. Hemocyanin from spiny lobster behaves as a catecholoxidase. Kinetic characterization using dopamine, L-DOPA and catechol shows that dopamine is the most specific substrate. Catechol and dopamine produced substrate inhibition above 16 and 2 mM respectively. Mechanism-based inhibition was also evidenced for the three substrates, being less significant for L-DOPA. SDS-activated phenoloxidase activity is produced by the hexameric hemocyanin. Zymographic analysis demonstrated that incubation of native hemocyanin with trypsin and chymotrypsin, produced bands of 170 and 190 kDa respectively, with intense phenoloxidase activity. Three polypeptide chains of 77, 80 and 89 kDa of hemocyanin monomers were identified by SDS-PAGE. Monomers did not show phenoloxidase activity induced by SDS or partial proteolysis.     

Perception of odor mixtures by the spiny lobster Panulirus argus

We used spiny lobsters (Panulirus argus) in a discriminationlearning procedure with aversive conditioning to examine theirbehavioral discrimination of adenosine-5'-monophosphate (AMP),betaine, L-cysteine and their binary mixtures. Our results showthat spiny lobsters can clearly discriminate among binary mixturesand their components. Lobsters aversively conditioned to avoidresponding to a binary mixture continued to respond to thatmixture's components, and lobsters that were aversively conditionedto avoid responding to a compound tended to continue to respondto binary mixtures containing that compound. Thus, responsesof conditioned lobsters to binary mixtures were not usuallyintermediate between the responses to the mixtures' components,which might be expected for response-matched compounds. Thisresult might arise from any of several factors. First, it mightresult from mixture interactions in the peripheral olfactorysystem, if the responses of olfactory receptor neurons to onecomponent of a binary mixture were suppressed by the other component,making the response to the mixture more similar to the suppressingcomponent. Electrophysiological data from a population of 50singly-recorded olfactory receptor neurons (Daniel and Derby,1994) do not consistently support this idea. A second possiblereason for the behavioral response to a binary mixture not beingintermediate between the responses to its components involveshigher order processing, such as mixture interactions generatedin olfactory interneurons in the CNS (which is known to occur:Derby et al., 1985; Ache, 1989), configural learning or associativeprocessing.     

Differences in life-history and ecological traits between co-occurring Panulirus spiny lobsters (Decapoda,Palinuridae)

Coexistence of closely related species may be promoted by niche differentiation or result from interspecific trade-offs in life history and ecological traits that influence relative fitness differences and contribute to competitive inequalities. Although insufficient to prove coexistence, trait comparisons provide a first step to identify functional differences between co-occurring congeneric species in relation to mechanisms of coexistence. Here, a comparative review on life history and ecological traits is presented for two pairs of co-occurring species of spiny lobsters in the genus Panulirus: Panulirus gracilis and Panulirus inflatus from the Eastern Central Pacific region, and Panulirus argus and Panulirus guttatus from the Caribbean region. Panulirus gracilis and Panulirus inflatus have similar larval, postlarval, and adult sizes and a similar diet, but differ in degree of habitat specialization, fecundity, and growth rate. However, little is known on behavioral traits of these two species that may influence their competitive abilities and susceptibility to predators. The more abundant information on Panulirus argus and Panulirus guttatus shows that these two species differ more broadly in degree of habitat specialization, larval, postlarval and adult sizes, diet, fecundity, growth rate, degree of sociality, defense mechanisms, susceptibility to predators, and chemical ecology, suggesting a greater degree of niche differentiation between Panulirus argus and Panulirus guttatus than between Panulirus gracilis and Panulirus inflatus. Whether the substantial niche differentiation and apparent interspecific trade-offs between Panulirus argus and Panulirus guttatus relative to Panulirus gracilis and Panulirus inflatus reflect an earlier divergence of the former pair of species in the evolution of the genus constitutes an intriguing hypothesis. However, whether or not post-divergence evolution of each species pair occurred in sympatry remains uncertain.     

Glucose and sulfate conjugation of phenolic compounds by the spiny lobster (Panulirus argus)

Previous work has shown that the hepatopancreas of the spiny lobster (Panulirus argus) contains a mixed-function oxidase system capable of catalyzing the monooxygenation of polycyclic aromatic hydrocarbons to highly toxic products similar to those formed by mammalian tissues. Studies were designed to determine the ability of the spiny lobster to conjugate the phenolic compounds 4-methylumbelliferone, p-nitrophenol, beta-naphthol, and 3-hydroxybenzo[a]pyrene with endogenous molecules. The hepatopancreas contained UDP-glucose (UDPG) dependent glucosyltransferase, while no activity was detected when UDP-glucuronic acid was used as the cosubstrate. Atypical Michaelis-Menten kinetics result with varying concentrations of UDPG, indicating that multiple forms of glucosyltransferase may exist in this organ. The activity was localized in the microsomal fraction, exhibited a pH optimum at 8.0-8.5, and a temperature optimum of 30 degrees C. Sulfate conjugation was found only in the cytosolic fraction of the antennal gland and used adenosine 3'-phosphate 5'-phosphosulfate (PAPS) as the sulfate donor (Km(apparent) = 9.0 +/- 4.9 microM). Hepatopancreas cytosol inhibited sulfotransferase activity. The pH optimum of antennal gland sulfotransferase was a function of the substrate and ranged from 5.5 to 7.4. Analysis of spiny lobster urine 24 hr following exposure to 3-hydroxybenzo[a]pyrene demonstrated the ability of the lobster to form both the sulfate and glucoside conjugate in vivo.     

Isolation and characterization of the mitochondrial DNA from the florida spiny lobster, Panulirus argus

1. Mitochondria and mitochondrial DNA were isolated from the digestive gland of Panulirus argus. 2. The mitochondrial DNA has an average contour length of 5.13 microns which corresponds to a molecular weight of 10.10 X 10(6) daltons. 3. The molecular weight based on agarose gel electrophoresis of restricted individual DNA samples ranges from 10.04 to 10.4 X 10(6) daltons. 4. Restriction endonuclease analysis with Bam H1 and Eco R1 demonstrate variation in nucleotide sequence between individual lobsters.     

Integumental organs of the phyllosoma larva of the rock lobster Jasus edwardsii (Hutton)

The external morphology and distribution of the integumentalorgans of the final-stage phyllosoma of the rock lobster Jasusedwardsii were examined. Seven types of organs were recognizedon the integument of the body trunk, antennules and antennae:plumose setae, simple setae, porous setae, aesthetasc setae,simple pores, dorsal cuticular organs and dome-shaped structures.The plumose setae and simple pores were abundant on the dorsalsurface of the cephalosome, abdomen and telson. The dorsal cuticularorgans were present only on the dorsal surface of the cephalosome,and the aesthetasc setae were restricted to the antennule. A comparison of the morphology of these organs with the senseorgans of other decapods with known function suggests that thedorsal surface of the body trunk is one of the major sites ofreception of near-field water movement in the Jasus phyllosoma.     

Luminous vibriosis in rock lobster Jasus verreauxi (Decapoda: Palinuridae) phyllosoma larvae associated with infection by Vibrio harveyi

Studies were conducted to determine the cause of outbreaks of luminous vibriosis in phyllosoma larvae of the packhorse rock lobster Jasus verreauxi reared in an experimental culture facility. On 2 separate occasions mortalities of up to 75% over a period of 4 wk were observed in 4th to 5th and 8th to 10th instar phyllosomas at water temperatures of 20 and 23 degrees C, respectively. Affected larvae became opaque, exhibited small red spots throughout the body and pereiopods, and were faintly luminous when viewed in the dark. Histopathology showed that the gut and hepatopancreas tubules of moribund phyllosomas contained massive bacterial plaques. The hepatopancreas tubules of moribund larvae were atrophic and some contained necrotic cells sloughed into the lumen. Dense, pure cultures of a bacterium identified as Vibrio harveyi were isolated from moribund larvae. The disease syndrome was reproduced by in vivo challenge and V. harveyi was successfully reisolated from diseased larvae after apparently healthy larvae were exposed by immersion to baths of more than 10(4) V. harveyi ml(-1) at 24 degrees C. Injured larvae were more susceptible to infection than were healthy larvae. Survival of larvae experimentally and naturally exposed to V. harveyi was improved when antibiotics were administered via bath exposures.     

Morphology and function of the antennular joint and its strand organ,instrumental to gravity reactions in the spiny lobster Panulirus argus (Crustacea,Decapoda)

Summary The one-point joint linking the antennula with the carapace in Panulirus argus is described. A strand organ is activated when the antennula is moved in the vertical plane. Its structure, function, and regeneration after severance were investigated.The implications of this system are discussed, starting from the findings that the strand organ counteracts the statocyst (located in the antennula) in such a way that gravity reactions occur only if the body changes its position with respect to gravity.The work was supported by grants from the Max-Planck-Gesellschaft (Hedwig Schöne), the National Science Foundation of the U.S.A., the American Philosophical Society, and the Cecil Montgomery-Moore Fellowship of the Bermuda Biological Station. Contribution No. 836 of the Bermuda Biological Station     

Primary culture of hemocytes from the Caribbean spiny lobster, Panulirus argus, and their susceptibility to Panulirus argus Virus 1 (PaV1)

Primary cultures of hemocytes from the Caribbean spiny lobster Panulirus argus were developed for studies on the in vitro propagation of Panulirus argus Virus 1 (PaV1). A modified Leibovitz L-15 medium supported the best survival of hemocytes in in vitro primary cultures. However, degradation of the cultures occurred rapidly in the presence of granulocytes. A Percoll step gradient was used to separate hemocytes into three subpopulations enriched in hyalinocytes, semigranulocytes, and granulocytes, respectively. When cultured separately, hyalinocytes and semigranulocytes maintained higher viability ( approximately 80%) after 18 days incubation compared with granulocytes, which degraded over 2-3 days. Susceptibility of the cell types was investigated in challenge studies with PaV1. Hyalinocytes and semigranulocytes were susceptible to PaV1. Cytopathic effects (CPE) were observed as early as 12h post-inoculation, and as the infection progressed, CPE became more apparent, with cell debris and cellular exudates present in inoculated cultures. Cell lysis was noticeable within 24h of infection. The presence of virus within cells was further confirmed by in situ hybridization using a specific DNA probe. The probe gave a unique staining pattern to cells infected with PaV1 24-h post-inoculation. Cells in the control treatment were intact and negative to hybridization. This assay was further applied to the quantification of infectious virus in hemolymph using a 50% tissue culture infectious dose assay (TCID(50)) based on CPE. These tools will now allow the quantification of PaV1 using established culture-based methods.     

A CUB-serine protease in the olfactory organ of the spiny lobster Panulirus argus.

csp, a gene encoding a protein with high sequence identity to trypsinlike serine protease and CUB domains, was identified from a cDNA library from the olfactory organ (antennular lateral flagellum) of the spiny lobster Panulirus argus. The full-length cDNA sequence of csp is 1801 bp, encoding a protein of 50.25 kD, with three domains: signal peptide, trypsinlike serine protease, and CUB (named for a class of compounds including Complement subcomponents Clr/Cls, Uegf, and Bone morphogenic protein-1). RT-PCR, Northern blots, and immunoblots showed that csp is predominantly expressed in the lateral flagellum and eyestalk. Immunocytochemistry showed that Csp is present in olfactory (aesthetasc) sensilla around auxiliary cells (glia that surround the inner dendrites of olfactory receptor neurons, ORNs) and ORN outer dendrites. We propose that Csp is expressed and secreted by auxiliary cells, associates with ORN cell membranes or extracellular matrix via the CUB domain, and has trypsinlike activity. In the eyestalk, Csp is associated with cells surrounding axons between neuropils of the eyestalk ganglia. Possible functions in the olfactory organ and eyestalk are discussed. To our knowledge, this is the first report from any olfactory system of a gene encoding a protein with serine protease and CUB domains.     

Effect of environmental parameters on immune response of the Indian spiny lobster, Panulirus homarus (Linnaeus, 1758)

The high export value of the Indian spiny lobster Panulirus homarus increasingly attracts the aquaculturists for farming and fattening. However, lack of knowledge on the effect of environmental parameters on the immune system of this animal could result in high mortality, which ultimately may cause major loss to the industry. Here, we report the effect of salinity (20, 25, 35, 40, and 45 per thousand), pH (5.0, 8.0, and 9.5), dissolved oxygen (DO) (1 and 5 mg L(-1)), and ammonia-N concentration (0, 0.5, 1.5 and 3 mg L(-1)) on the immune response of P. homarus measured in the haemolymph in terms of Total Haemocyte Count (THC), phenoloxidase (PO) activity, and NBT-reduction. Our data showed significant reduction (P<0.05) in THC, and NBT-reduction at lower (20 per thousand) and higher (45 per thousand) salinities. However, PO activity showed significant disparity, showing an increasing trend from 20 to 45 per thousand. Significant reduction (P<0.05) in THC and PO activity under acidic and alkaline conditions, under hypoxic condition (1 mg L(-1)), and at the higher ammonia-N concentrations than their respective optimal conditions were observed. Thus, suggesting that extreme environmental parameters can induce modifications in the immune system of the spiny lobster P. homarus, which may enhance their susceptibility to opportunistic pathogens. The humoral parameters such as THC, PO activity, and NBT-reduction can be used as potential stress indicators for healthy management of spiny lobsters.     

In the spiny lobster (Panulirus interruptus) the prophenoloxidase is located in plasma not in haemocytes

In the spiny lobster (Panulirus interruptus), unlike other crustaceans most of the prophenoloxidase (proPO) was detected in cell-free plasma (86.3%). In spite of its location, lobster proPO activating system has a similar activation mechanism to other crustacean proPO systems. Haemocyte lysate was able to activate the plasma proPO indicating location of the prophenoloxidase activating enzyme (PPAE) in haemocytes. Lobster haemocyte PPAE was isolated by affinity chromatography and its participation as activating enzyme was demonstrated. This enzyme is a serine-proteinase that transforms the inactive form (proPO) to an active one (phenoloxidase). The PPAE was also present in the cell-free supernatant of haemocytes previously incubated with Vibrio alginolyticus.     

Developmental changes in the structure and function of mouthparts of phyllosoma larvae of the packhorse lobster, Jasus verreauxi (Decapoda: Palinuridae)

Mouthpart morphology and feeding behaviour of Jasus verreauxi phyllosomas (instars 1-13) were examined using scanning electron microscopy and video analysis, respectively, to better understand ingestion and processing mechanisms and to identify developmental changes in feeding biology. The density, robustness and complexity of mouthpart setation increased with development, oral field increased and there were a greater number of spinose projections on maxillae 1 in mid and late instar phyllosomas. The second and third maxillipeds were able to sweep a larger area due to their increased length, which effectively increased the size of the oral field. Changes in feeding behaviour were consistent with these morphological differences between instars. In late instars, the shredding and tearing efficiency of maxillae 1 increased, larger pieces of prey were pushed between the mandibles, and the mandibles were able to effectively grind food due to a slight rotation away from the transverse plane. Both morphological and behavioural observations suggests that the absolute size range of prey increases with phyllosoma body size and the prey processing (i.e. ability to capture, manipulate and grind prey) becomes more efficient with development. We suggest early instar phyllosoma are most suited to a diet comprising softer prey items, whereas later-instar phyllosoma are better equipped to deal with larger, fleshier prey.