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Over 1200 squids were captured by night lighting, trawling, or seining in the northern Gulf of Mexico for laboratory maintenance. Two types of recirculating sea water systems were designed and evaluated: a 2 m circular tank (1500 liter capacity) and a 10 m long raceway (10,000 liters). Mean laboratory survival was: Loligo plei (12 to 252 mm mantle length, ML) 11 days, maximum 84 days; Loligo pealei (109 to 285 mm ML) 28 days, maximum 71 days; Lolliguncula brevis (27 to 99 mm ML) 19 days, maximum 125 days. Smaller squids showed significantly poorer survival than larger ones. All squids fed well on a variety of live estuarine fishes and shrimps. Growth rates depended upon stage of maturity. The highest rates were Loligo plei 59 mm/month (23.8 g/mo), Loligo pealei 77 mm/mo (67.3 g/mo), and Lolliguncula brevis 31 mm/mo (17.2 g/mo). General aspects of behavior and body patterning were species-specific and were useful indices of the squids' condition. Key factors for laboratory survival were (1) prevention of skin damage, (2) tank systems with sufficiently large horizontal dimensions, (3) high quality water, (4) ample food supply, (5) no crowding, (6) maintaining squids of similar size to reduce aggression and cannibalism, and (7) segregating sexes to reduce aggression associated with courtship, mating, and egg laying.

mals, suggesting that these organisms could simply be parasitic (IO, 11). Further work will focus on culturing, identifying, and characterizing the organisms responsible for the DNA sequences found in the bacterial community of the ANG of Lo/igo pealei, and will seek to detect and identify other members of the community. This combination oftraditional culture approaches with molecular analyses provides evidence of a much more diverse bacterial community within the ANG of Loligo pealei than had been observed previously. This molecular approach indicates the presence of different and unexpected bacterial types. Particularly novel is the possibility that phototrophic bacteria may play a role or roles in the ANG. We note that although the molecular data presented are not complete, they permit the formulation of sound hypotheses for further investigation, in combination with the microbiological and physiological techniques essential to develop a reasonable understanding of the composition and function of the ANG bacterial community. We thank members of the MBL Microbial Diversity Course staff and faculty, in particular the Course Directors, E. Leadbetter and A. Salyers, for logistical support and valuable discussions on the project, B. Paster for assistance with molecular analyses, P. Dunlap for discussions on ANG research, and J. Armitage for discussions on phototrophic bacteria. The course was supported by the Office of Naval Research, the Department of Energy, and the Foundation for Microbiology.

6. 323 in The Cuttlejish. First Int. Symp. on the Cuttlefish Sepia., E. Boucaud-Camou, ed. Centre de publication de I’Universitt de Caen, France. Forsythe, J. W., R. H. DeRusha, and R. T. Hanlon. 1994. .I. Zool. (Land.) 233: 175-192. DeRusha, R. H., J. W. Forsythe, F. D. DiMarco, and R. T. HanIon. 1989. Lab. Anim. Sci. 39: 306-312. Hanlon, R. T., and J. F. Forsythe. 1990. Pp. 23-46 in Diseases of Marine Animals. Vol3, 0. Kinne, ed. Biologische Anstalt Helgoland, Hamburg, Germany. Oestmann, D. J., J. M. Scimeca, J. Forsythe, R. T. Hanlon, and P. Lee. 1997. Lab. Anim. Sci. Contemporary Topics 36: 89-92.

We report the protein isolation, cloning and characterization of members of an unusual protein family, which comprise the most abundant proteins present in the squid eye. The proteins in this family have a range of molecular weights from 32 to 36 kDa. Electron microscopy and detergent solubilization demonstrate that these proteins are tightly associated with membrane structures where they may form tetramers. Despite this, these proteins have no stretches of hydrophobic residues that could form typical transmembrane domains. They share an unusual protein sequence rich in methionine, and contain multiple repeating motifs. We have therefore named these proteins Methionine-Rich Repeat Proteins (MRRPs). The use of structure prediction algorithms suggest very little recognized secondary structure elements. At the time of cloning no sequence or structural homologues have been found in any database. We have isolated three closely related cDNA clones from the MRRP family. Coupled in vitro transcription/translation of the MRRP clones shows that they encode proteins with molecular masses similar to components of native MRRPs. Immunoblot analysis of these proteins reveals that they are also present in squid brain, optic lobe, and heart, and also indicate that MRRP-like protein motifs may also exist in mammalian tissues. We propose that MRRPs define a family of important proteins that have an unusual mode of attachment or insertion into cell membranes and are found in evolutionarily diverse organisms.

Previous behavioral observations of Loligo pealeii revealed the potential for multiple paternity within individual egg capsules, each containing 100 to 300 eggs. Five egg capsules, sam- pled from 3 nearshore locations over 2 yr, were tested for multiple paternity using 3 microsatellite loci. The minimum number of potential fathers was derived from the number of different alleles pre- sent in the progeny. All 5 egg capsules exhibited multiple paternity: genetic markers of at least 4 fathers were found in 2 egg capsules; at least 3 fathers were found in 1 egg capsule, and at least 2 fathers were found in the remaining 2 egg capsules.

Ten prey taxa were recorded from the stomach contents of eight long-finned pilot whales (Globicepbala melas) independently stranded along the U.S. mid-Atlantic coast. Relative importance of prey species was determined by methods that incorporate prey frequencies of occurrence, proportions of numerical abundance, and proportions of reconstructed mass. Separate analyses of trace (free, durable body parts representing well-digested prey items) and non-trace (relatively intact prey specimens) food material were conducted in order to address biases caused by differential rates of digestion and passage through the gastrointestinal tract. Different measures of prey importance yielded varying results, but the long-finned squid (Loligo pealei) was the most important prey species regardless of how prey importance was defined. Fishes were relatively unimportant in the diet. Our results indicate that the diets of western North Atlantic long-finned pilot whales differ substantially from what has been previously reported in the literature and that results from food-habits studies that utilize different techniques may not be comparable.

High-speed ciné recordings of prey capture by the squid Loligo pealei were used to analyze the kinematics of the rapid tentacular strike. The proximal portion of the tentacle, the stalk, elongates during the strike. The non-extensible distal portion of the tentacle, the club, contacts the prey and attaches using suckers. Seven sequences of prey capture filmed at 750 frames s−1 were analyzed frame by frame. The positions of the head, the tentacles and the prey were digitized, and the data were smoothed using quintic natural B-splines and the generalized cross-validation (GCV) criterion. During the strike, the animal swims forward at velocities ranging from 0.7–1.2 m s−1, and as the eight arms are flared, the tentacular stalks elongate. Tentacular extension occurred in approximately 20–40 ms with peak strains in the tentacular stalk ranging from 0.43–0.8. Peak longitudinal strain rates varied from 23–45 s−1. Maximum extension velocities of the stalk were calculated to be over 2 m s−1 with peak accelerations of approximately 250 m s−2. Once the tentacular clubs have contacted the prey, the tentacular stalks are frequently observed to buckle.

The domestic butterfish (Peprilus triacanthus) fishery off the Northeast USA has increased in importance in recent years, to the extent that the quantity allocated to foreign countries fishing within USA waters has been decreased to by-catch levels. This restriction resulted in closure of a portion of the foreign squid fishery in 1985, when the by-catch quota for butterfish was exceeded. This analysis is designed to determine co-occurrence between long-finned squid (Loligo pealei) and butterfish particularly in directed fisheries for each species with a view that areal, diel, and/or seasonal regulations of these fisheries may be feasible to reduce the potential adverse effects of high by-catch rates. Squid and butterfish exhibited high degrees of overlap in temperature and depth preferences as indicated by seasonal and spatial distribution data from research and fishery sources. Commercial fishery data, however, suggested that by-catch of butterfish in the directed squid fishery can be maintained at relatively low levels (

Catch data from research vessel surveys were used to determine if statistical measures of spatial dispersion can be useful in predicting the availability of migratory, schooling species to specific seasonal fisheries. As an example, spring and autumn bottom trawl catches of the migratory longfin squid Loligo pealei were used to calculate three measures of the species' dispersion in the U.S. Middle Atlantic Bight. Commercial catch per unit effort served as an index of longfin squid availability to the inshore (primarily spring–summer) fishery. Results suggested that indices of dispersion for stocks that do not remain within the area of the fishery throughout the year may be more useful in predicting subsequent availability than are indices of relative abundance. The simplest of the three measures examined here–the proportion of tows within a survey yielding no individuals of the species, calculated from the autumn survey data–exhibited a significant negative correlation with the index of availabil...

SUMMARYThe contractile properties of the transverse muscle of the tentacles and the transverse muscle of the arms of the squid Loligo pealei were investigated using small muscle fibre bundle preparations. In addition,transmission electron microscopy was used to measure the length of the thick myofilaments of the two muscle fibre types. The thick filament length of the cross-striated tentacle fibres was 0.81±0.08 μm (mean ± S.D, N=51) while that of the obliquely striated arm muscle fibres was 7.41±0.44 μm (N=58). The difference in thick filament length of the two muscle types was predicted to result in a much higher shortening velocity of the tentacle muscle compared with the arm muscle. This was tested by investigating the force/velocity relationship for isotonic shortening of the two muscle types. Fitting Hill's equation to the results gave a maximum shortening velocity (Vmax, the intercept on the velocity axis) of 15.4±1.0 L0 s-1(mean ± S.D., N=9) for the tentacle fibres and of 1.5±0.2 L0 s-1 (N=8) for the arm fibres, where L0 is the length at which peak isometric force was recorded. The difference in thick filament length was also predicted to result in lower peak tension in the tentacle versus the arm muscle. For the tentacle, the mean peak tetanic tension during a brief isometric tetanus (0.2s) of 131±56 mN mm-2 cross-sectional area (mean ± S.D., N=12) was observed at a stimulus frequency of 80 Hz, whereas the mean peak tetanic tension of the arm fibres during a brief isometric tetanus (0.2s) was 468±91 mN mm-2(N=5) and was observed at a stimulus frequency of 160 Hz. The length/force relationships (expressed relative to L0) of the two muscle types were similar. The ratio of twitch force to peak tetanic force was 0.66 in the tentacle fibres, but only 0.03 in the arm fibres.

Na+/Ca2+exchange has been investigated in squid ( Loligo pealei) rhabdomeric membranes. Ca2+-containing vesicles have been prepared from purified rhabdomeric membranes by extrusion through polycarbonate filters of 1-μm pore size. After removal of external Ca2+, up to 90% of the entrapped Ca2+could be specifically released by the addition of Na+; this finding indicates that most of the vesicles contained Na+/Ca2+exchanger. The Na+-induced Ca2+efflux had a half-maximum value ( K1/2) of ∼44 mM and a Hill coefficient of ∼1.7. The maximal Na+-induced Ca2+efflux was ∼0.6 nmol Ca2+⋅ s−1⋅ mg protein−1. Similar Na+-induced Ca2+effluxes were measured if K+was replaced with Li+or Cs+. Vesicles loaded with Ca2+by Na+/Ca2+exchange also released this Ca2+by Na+/Ca2+exchange, suggesting that Na+/Ca2+exchange operated in both forward and reverse modes. Limited proteolysis by trypsin resulted in a rate of Ca2+efflux enhanced by approximately fivefold when efflux was activated with 95 mM NaCl. For vesicles subjected to limited proteolysis by trypsin, Na+/Ca2+exchange was characterized by a K1/2of ∼25 mM and a Hill coefficient of 1.6. For these vesicles, the maximal Na+-induced Ca2+efflux was about twice as great as in control vesicles. We conclude that Na+/Ca2+exchange proteins localized in rhabdomeric membranes mediate Ca2+extrusion in squid photoreceptors.

The goal of this study was to obtain a complete description of the elastic modulus and hysteresis of the mantle tissue of the squid Loligo pealei over the entire functional region of the mantle. In addition, in vivo strains were measured to allow calculations of the amount of energy stored and returned in each region of the mantle studied, and microscopic analysis of the tissue was carried out with the aim of correlating macroscopic properties with microscopic structure. The results of dynamic tissue tests indicate that mean elastic moduli for each of the 35 mantle positions tested ranged from 5.0×105 to 1.2×106 N m−2. The elastic modulus varied within a narrow range, in no predictable manner. Mean hysteresis values for each position varied from 19.7 % to 27.3 % with no discernible patterns found either around or along the mantle. In vivo mantle strains peaked in the middle (lengthwise) of the mantle and declined towards both ends, and the absolute strains increased with increasing swimming velocity. Energy storage calculations showed that most energy was stored in the middle of the mantle, with an increase in storage with increased swimming velocity. Microscopic tissue analysis found direct correlations between macroscopic properties and microscopic characteristics, and electron microscopical analysis of all three types of intramuscular fibre revealed that all three types are collagenous in nature.

Like many cephalopods, females of the squid species Loligo pealei have a pair of accessory nidamental glands (ANG) that harbor a dense bacterial community (Bloodgood, 1977). The ANG is closely associated with the nidamental gland, which produces capsule-like membranes surrounding the eggs (Fig. 1). Because of its close association with the nidamental gland and the oviduct, the ANG probably plays a role in protecting the eggs by coating them with bacteria (Barbieri et al., 1997; Biggs & Epel., 1991). Recently, identical or very similar bacteria have been found in the ANG and in the egg cases of Loligo pealei (Barbieri et al., unpublished results).

Stomach contents from 30 long-finned pilot whales Globicephala melas captured incidentally in the Distant Water Fleet (DWF) mackerel fishery off the northeastern United States were examined. Several methods of assessing prey importance were used in order to construct a true representation of the pilot whale diet. Separate analyses of trace (free, durable body parts from well-digested prey) and non-trace (relatively intact prey) food materials were conducted to address biases caused by differential rates of digestion and passage. Squids dominated the diet and long-finned squid Loligo pealei was the most important prey, but we noted large yearly fluctuations in prey importance. Metric multidimensional scaling analyses of trace and non-trace stomach contents of individual whales suggest that many animals were cuaght while feeding opportunistically near fishing operations, resulting in a bias of non-trace (intact) stomach contents. The diversity of prey in this study was greater than previous reports of the food habits of western North Atlantic non-finned pilot whales.

Se presenta una descripción de las principales características, estadios y procesos que ocurren durante el desarrollo embrionario del calamar tropical Sepioteuthis sepioidea a partir de masas ovígeras localizadas en el medio ambiente natural, incubadas en condiciones de laboratorio (salinidad 35 ‰, temperatura 25°C y fotoperíodo de 12 Hr). Se encontró que el desarrollo embrionario de esta especie es similar al descrito para Loligo pealei y Sepia officinalis, con una duración aproximada de 40 días bajo las condiciones de incubación empleadas. Los procesos de blastulación y gastrulación ocupan un 25% del tiempo total de desarrollo de la especie (entre 10 y 12 días) y la organogénesis un 75% (entre 28 y 30 días). A description of the main characteristic stages and processes of embrionic development of Sepioteuthis sepioidea egg clusters collected in their natural enviroment is presented. Eggs were incubated in laboratory conditions (salinity 35 ‰, temperature 25°C, photoperiod 12 hrs.). Embrionic development of this species is similar to that described for Loligo pealei and Sepia officinalis with an approximate duration of 40 days in laboratory. Blastulation and gastrulation processes of the species consumed 25% of the total developing time (10 to 12 days) and organogenesis the last 75% (28 to 30 days).

1. 1. Synaptic transmission at the squid giant synapse was blocked in 45 min by exposure to 0.02 atm oxygen but was maintained for more than 90 min in air (0.21 atm oxygen) or pure oxygen (1 atm). 2. 2. Excitatory post-synaptic potential amplitude decreased in 0.02 atm oxygen but did not change in either 1 or 0.21 atm oxygen. Fast facilitation was increased in 0.02 atm oxygen only. 3. 3. Post-synaptic resting membrane potential (Vm and input resistance (Ro) remained unchanged in 1 or 0.21 atm oxygen but Ro was increased in 0.02 atm oxygen. 4. 4. Our results suggest that severe hypoxia decreased the release of transmitter from the pre-synaptic terminal.

The squid giant axon has been the object of study by neurobiologists for almost 50 years. It arises in the stellate ganglion as the syncytial fusion of several hundred small axons arising from separate ganglionic cells. Depending upon the squid species of origin, the diameter of the giant axon can vary from 200 µm to 1500 µm. The most commonly used species, Loligo pealei and L. forbesi, have axons with diameters of 400–900 µM. The large size of the axon functionally serves to permit the rapid conduction of action potentials by reducing the electrical resistance of the axoplasm. Thus, the axon serves to rapidly transmit excitatory signals to the musculature of the mantle wall thereby permitting rapid escape or attack movements.

Like other cephalopods, squid have magnificent visual systems, the development of which has been too little studied in recent times. The structure of the eye (Fig. 1) is described in another chapter (Saibil, 1990), while the adult organization of the optic lobe is well described in Loligo (Kopsch, 1899; Young, 1974). This chapter will review the development of both, and the methods appropriate to that task, in an account drawn entirely from the literature; works on coleoids other than teuthoids are cited only when evidence is lacking in squid and to identify areas in which interesting findings would be forthcoming. The visual system will be interpreted conservatively so as not to include the extraocular photoreceptors in the paraolfactory vesicles, found in squid (Mauro, 1977; Young, 1978); the development of another system of cephalopod extraocular photoreceptors found in octopods, the epistellar body, has already been described (Sacarras:), 1956). The prospects for developmental studies on squid have recently improved with the prolonged culture of healthy animals in captivity (Hanlon, 1990). Squid mating behavior is described for Loligo pealei by Arnold (1962, 1990); embryos are obtained by methods described by Arnold (1974, 1990) and Hanlon (1990). Developmental stages are provided for Loligo vulgaris by Naef (1928), as amended by Meister (1972), and by Arnold (1965a, 1974, 1990) who provides a comprehensive illustrated timetable for Loligo pealei; a table of the events of eye morphogenesis at closely spaced intervals (Marthy, 1973) cross refers to these.

Long ago and far away [from Newfoundland], this story begins. The designation Loligo pealei first appears in a paper read at a meeting of the Academy of Natural Sciences of Philadelphia on the evening of March 20th, 1821, by the then curator Charles Alexandre Lesueur (1778–1846). Born in LeHavre, France, he early became noted for his talents at sketching, drawing and painting natural history specimens. He had a most successful four years (1800–1804) with Francois Peron on the GEOGRAPHIE Expedition to Australia and Tasmania, which saw the collection of some 100,000 zoological specimens, from which 2,500 new species were described and ultimately published. Only the first volume of results from these collections was published before Peron’s death. Peron bequeathed all his unfinished manuscripts “to the most intimate friend, to the faithful companion of (my) work and research in natural history, to the good and faithful M. Lesueur.”

Methodology was developed to measure quality in cooked squid mantle that included sensory evaluation, instrumental texture measurement by use of a modified Kramer shear cell, and physical and chemical properties such as pH, protein release and weight loss. These techniques were then used to evaluate the influence of freezing, refrigerated holding and cooking on the two major North Atlantic commercial squid species, lllex illecebrosus and Loligo pealei. Refrigerated holding produced significant increases in pH of cooked mantle as did longer cook times. Frozen lllex released more soluble protein into the cook water than the other treatments, and longer holding and cooking times produced significant increases in protein levels. Weight losses of over 50% were common during cooking; virtually all the loss could be accounted for as water. Frozen lllex lost the most weight and this parameter increased significantly with both holding and cooking times. Sensory judges indicated texture was a primary quality factor and their most common complaint was a tough or rubbery texture. A sensory index was calculated that provided a single composite score for each sample. This index correlated very significantly with shear values and both parameters were greatly influenced by cooking. Boiling squid mantle reduced shear values and increased quality, probably as a result of thermal gelatinization of the large amount of collagen present in this tissue. The longest cook period (32 min) produced the best sensory quality squid. Holding squid, either fresh or thawed, on ice for up to 5 days significantly reduced quality in lllex but not Loligo; this deterioration likely results from endogenous proteolytic enzymes. Loligo was generally preferred more than lllex in terms of overall acceptability. Kramer shear values were significantly higher for previously frozen samples of both species and fresh lllex toughened during holding. These observations led to amine analysis that showed formaldehyde production, presumably by an enzymatic route from trimethylamine oxide, which could be responsible for protein crosslinking and subsequent toughening.

1. A DFPase has been purified several thousand-fold from the head ganglion and from the hepatopancreas of squid by a combination of ammonium sulfate precepitation, DEAE-cellulose chromatography, gel filtration, and isoelectric focusing. 2. The DFPase from head ganglion is identical with that from hepatopancreas, and is either not found in other species outside the class Cephalopoda , or found in only very small quantities, or is a different kind of enzyme. Although previous evidence suggested a relationship between the squid-type DFPase and the presence of isethionate, the major anion of the squid nerve, the absence of isethionate from squid hepatopancreas now suggests that such a relationship either does not exist, or is, at most, indirect.

The wide range of cholesterol values given in the literature for Loligo pealei and Illex illecebrosus is confusing to people who are designing low cholesterol diets for health purposes. These species were analyzed for proximate composition, fatty acid content, and cholesterol content in order to provide information to consumers and health care professionals. A sampling of both species of squid over a 2-yr period revealed that cholesterol values ranged from about 110 mg up to 450 mg/100g raw tissue with no apparent correlation with season or location of catch. The wide range of values, therefore, seems to reflect natural occurences. Omega-3 fatty acids make up over 50% of the total fatty acids, but these squid, because they are low in fat (about 1.5%), contribute only about 0.5g of these fatty acids per 100g in the diet.

A necrotic exfoliative dermatitis of captive squid, Loligo pealei , is described. The clinical, gross, and histologic features of the disease are given. The disease is progressive and is defined in three stages, culminating in massive exfoliation of the skin and death of the animal. Microscopic lesions are intimately associated with uniform populations of bacteria, consisting of chains of Gram-negative, long filamentous rods. A description of the normal histologic structure of the skin is presented. The etiologic agent of this disease has not been demonstrated.

SEM was used to reveal progressive structural alterations in the tissue components of cooked squid mantle. Progressive changes were observed at various cook temperatures, 50, 60, 70, 80 and 100°C and after different periods of cooking, 1, 2, 4, 8,16, 32 and 64 min at 100°C. Thermal alterations of connective tissues first appeared as interfibril ‘melting,’ then total fiber gelatinization at higher temperatures. The onset temperatures of ‘melting’ and gelatinization differed depending on the anatomical location of the connective tissue tunics. Thermal alterations of muscle fibers appeared as a loss of myofibril distinction first evident at 50°C. Increasing temperature of muscle fibers caused, in order, coagulation of sarcoplasmic proteins, disintegration of the sarcoplasm, and continuous fiber shrinkage and dehydration. These changes in tissue structure were partially explained by simultaneous changes in gross body dimensions, and mantle pH, moisture, and protein content.

Instrumental tests and profile panel evaluations were used to characterize the textural attributes of squid mantles cooked in water to 50, 60, 70, or 80°C, or cooked for 1, 4, 8, 16, or 32 min after reaching 100°C. A comparison of results from each specific cook treatment was used to interpret textural changes caused by heat and duration of heating at 100°C. Shear type tests, a single blade, and a punch and die, demonstrated that the amount of force and energy required to cut cooked mantles was dependent upon the orientation of the shearing apparatus relative to the direction of muscle fibers and on the side of the mantle initially cut. These anisotropic and nonhomogeneous aspects of the cooked mantle are due to thermal hardening of muscle fibers and to the distribution and heat gelatinization of connective tissues. A unique isometric tension test demonstrated that hydrothermal shrinkage of connective tissues also influenced squid texture. Panel evaluations indicated that two groupings of textural character notes best described texture of cooked squid. Character notes assessing mantle strength correlated with the results of rheological tests. Character notes denoting mantle moisture were not explained by instrumental tests, but were an essential supplement describing the mouthfeel of cooked squid.

1. 1. Blood pressure and heart rates were measured in unrestrained Loligo pealei . 2. 2. At minimal activity levels systolic and diastolic pressures in the anterior aorta were 7.18 and 2.72 kPa respectively and heart rates were 102 beats per minute. 3. 3. Peak and low pressures in the afferent branchial vessel were 0.92 and 0.04 kPa while mean pressures in the anterior vena cava and efferent branchial vessel were 0.32 and 0.18 kPa. 4. 4. These blood pressures at rest are the highest reported to date for any cephalopod and are probably indicative of the active pelagic existence of these squid.

Giant fiber lobe (GFL) cells obtained from healthy squid reliably produced neuritic processes in culture. The processes were of two types, a sheet-like veil or thin branching neurites. The latter type was often associated with bulbous expansions (presumptive growth cones), at the termini, at branch points, or at sites of apparent contact among branches from two different cells. On poly-L-lysine substrate, veiling usually occurred by the fourth or fifth day in culture, while the branching processes appeared by one week to ten days. The elaboration of the outgrowths by the GFL neurons was influenced by the culture substrate and incubation temperature. The development of a preparation in which isolated GFL somata extend neurites in an easily controlled environment will permit the detailed study of axon fusion, channel expression and turnover, and synapse formation in the neurons.

The methods were developed to study the properties of ion-sensitive acceptors of the terminal (gamma) phosphate of ATP in the axon-rich retinal nerve preparation of the squid Loligo pealei. 2. The bulk of ion-sensitive phosphorylation activities were due to CN− (2 mM) and ouabain (10−4 M)-sensitive systems. 3. By using different ion combinations and neuroactive agents, several types of phosphorylation systems were recognized.

1. 1. Enzymatic, electrophoretic, and immunological studies were carried out on a troponin-C-like protein from squid mantle muscle. 2. 2. This protein has analogous characteristics to other troponins-C, suggesting that the mechanism of thin-filament-linked regulation in squid muscle is similar to that in other muscles.

The difficulties of working on living squid have caused research into their cardiovascular performance to lag behind that done on octopods. Nonetheless, data that we do possess show squid to have cardiovascular capabilities above those of other cephalopods. In general, heart rate, blood pressure and cardiac output is higher for squid than for the other coleoids andNautilus. This higher circulatory system capability is in keeping with squid being relatively large, fast-swimming, pelagic cephalopods.

Publisher Summary This chapter discusses the cephalopod retinochrome. The cephalopod retina has a dual system of photosensitive chromoproteins with retinaldehyde as chromophores rhodopsin and retino-chrome. Rhodopsin is associated only with microvillar membranes of the outer segments of visual cells, whereas retinochrome is found in both inner and outer segments. The two photopigments differ from each other in the stereoisomeric form of their chromophore retinal, which is 11- cis in rhodopsin but all- trans in retinochrome. Retinochrome can be extracted also from the released fragments of outer segments. In the squid Loligo pealei , it is contained equally in both the inner and outer segments, and in Todarodes pacificus, much more is found in the outer segments. As retinochrome in the outer segments increases markedly during light adaptation of animal, it seems likely that some retinochrome protein moves forward from the inner to the outer segments and reacts there with metarhodopsin.

1. 1. The pH of Loligo hemolymph decreases by 0.021 ± 0.0005 pH units per °C between 5 and 25°C. 2. 2. The change in hemolymph pH with temperature is essentially the same as the change in the neutral pH of sea water over the same temperature range. 3. 3. Buffers with a pH-temperature dependence similar to that of hemolymph are recommended for in vitro studies of squid tissues.

The capture, transport, and maintenance of live adult Atlantic coast squid (Loligo pealei) are described. The objective was to obtain healthy live squid from a coastal region and to maintain them at an inland research facility long enough to provide at least 4 days of electrophysiological research. An inexpensive closed aquarium system is described, which utilizes an ion-exchange resin in the filter, that allows a typical survival time of at least 4.5 days. Similar closed aquarium systems may be of interest to other biophysicists who wish to maintain live squid away from coastal research facilities.

Illumination induced an increase in inositol polyphosphates, inositol 1,4-bisphosphate and inositol 1,4,5-trisphosphate, in the photoreceptors of the squid, Loligo pealei. There was a concomitant decrease in phosphatidylinositol 4,5-bisphosphate, but no light-induced change in any other phosphoinositide. None of these stimulus-induced changes were altered by treatment in vivo with pertussis toxin, which ADP-ribosylated a Mr-39000-peptide. These findings support the hypothesis that inositol 1,4,5-trisphosphate participates as either a messenger or a modulator in transduction in invertebrate photoreceptors.

Johann Heinrich von Thunen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung – Information on Fishery research in 2010

Publisher Summary This chapter reviews the factors that modulate intracellular pH (pH i ) and describes the active-transport mechanism responsible for pH i regulation in squid axons. The pH i of squid giant axons is of interest for two reasons. First, the squid axon serves as a valuable model of pH regulation in other systems and second, because numerous physiological processes are sensitive to changes in pH i . The experiments described in this chapter were performed in Woods Hole, Massachusetts, on giant axons of the squid Loligo pealei . The axons were dissected and cleaned according to standard practices and cannulated at both ends in a dialysis chamber. The experiments were of four types. In the first, the only additional manipulation was the insertion of two microelectrodes through opposite end-cannulas. In the second group of experiments, a dialysis tube as well as the microelectrodes was inserted into the axon. In the third and fourth group of experiments, isotopic fluxes of Na + and CI - were measured. These axons were internally dialyzed, but not impaled with microelectrodes.

Johann Heinrich von Thunen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung – Information on Fishery research in 2010

Impulse propagation velocity as a function of temperature in the range 5--20degreesC was obtained by external recording from the giant axon of Loligo pealei. The stellar nerve was set into a chamber allowing continuous superfusion, temperature control, and double recording of the impulse. Velocity was calculated from the interval between the spike peaks. The Q10 of velocity was about 1.8. At all temperatures, the velocity increased with time so that only data obtained during the 1st h or 2 could be generally considered to be comparable. Impulse block occurred below --3.4degreesC, in contrast to the giant axon of L. vulgaris, which blocks at about 0degreeC, but at the higher range of temperatures, the velocity in the L. pealei axons was not as well sustained as in those of L. vulgaris. The expected impulse velocity was calculated from Huxley's stability function f(beta) by approximating that function to a fourth-order polynominal and by substituting into it suitable ratios of available Q10 values relating to membrane conductance, ionic current, capacitance, and axoplasmic resistance. The calculation provided an improved fit to published experimental data on L. vulgaris. The difference in slope of the log velocity versus temperature plots, between the presumably warm acclimatized L. vulgaris and the cold-acclimatized L. pealei, was present in both experimental and calculated curves.

(1) A membrane fraction enriched in (Na+ +K+)-ATPase (EC 3.6.1.3) was obtained from optic ganglia of the squid (Loligo pealei) by density gradient fractionation of membranes followed by treatment with either SDS or Brij-58. The resulting membrane had an (Na+ +K+)-ATPase specific activity of approx. 2 units/mg and was greater than 95% ouabain-sensitive. (2) The (Na+ +K+)-ATPase had a Km for ATP of 0.42 +/- 0.04 mM and a pH optimum of 7.0. It was inhibited by ouabain with a Ki of 0.32 +/- 0.04 microM. (3) Optimum monovalent cation concentrations were: 240 mM NaCl, 60 mM KCl, tested with NaCl + KCl = 300 mM. (4) The Mg2+ dependence of hydrolysis varied with the absolute ATP concentration. At 3 mM ATP, the Km for Mg2+ was 0.86 +/- 0.10 mM, and at 6 mM ATP, the Km was 1.86 +/- 0.44 mM. High levels of Mg2+ caused inhibition of hydrolysis. (5) The interactions of Na+ and K+ were examined over a range of conditions. K+ levels caused modulations in the Na+ dependence in the range of 1-150 mM. (6) The (Na+ +K+)-ATPase prepared from squid optic ganglion displays properties similar to those of the sodium pump in injected nerves.