Showing papers in "The Biological Bulletin in 1989"
TL;DR: A case of very rapid evolution of resistance in a common freshwater benthic invertebrate, to sediment with extremely high levels of cadmium and nickel, to metal-polluted sites in Foundry Cove was identified.
Abstract: We identified a case of very rapid evolution of resistance in a common freshwater benthic invertebrate, to sediment with extremely high levels of cadmium and nickel. Limnodrilus hoffmeisteri from m...
252 citations
TL;DR: Cette revue enumere les differents peptides apparentes a la FMRF amide et tente d'elaborer un classement.
Abstract: Cette revue enumere les differents peptides apparentes a la FMRF amide et tente d'elaborer un classement. Description des peptides isoles chez les mollusques puis les peptides de cette meme famille chez d'autres animaux
173 citations
TL;DR: The results suggest that much of the time that resident lobsters spend outside shelters is used to remain familiar with their constantly changing physical and social environment.
Abstract: Over a three-year period (1978-1981) behavioral observations of the lobster, Homarus americanus, were made by snorkeling in a shallow cove. Three hundred and thirty-four (334) animals were individually marked and this was the only time they were disturbed. In summer, the resident population numbered about 30 animals. The size composition, activity patterns, and habitat use of this population are described in a companion paper (Karnofsky et al., 1989). Shelters are of prime importance in the life of the lobster. Lobsters spent most of their time in shelters, leaving only at night. They dug shelters under eelgrass, rocks, and boulders; shelter locations appeared clustered. Some animals changed shelters frequently whereas others occupied the same shelters for up to 10 weeks. Premolt behavior was characterized by multiple shelter use. Cohabitation in the same shelter occurred only during periods of pair formation: when a mature female shared a male's shelter prior to and following her molt. We report the only field evidence for such courtship cohabitation. Food foraging behavior was rare (0.35 instances/observation hour); most foraging involved live prey. Similarly, intraspecific interactions were surprisingly infrequent (0.2 instances/observation hour) and most, by far, did not involve physical contact. Although puncture wounds suggested intraspecific aggression, actual observations of escalating fights were rare. Premolt residents were involved in 65% of the interactions observed. In 70% of the interactions the larger animal won. However, smaller males and females could successfully defend their shelters against larger females. We report results from three homing experiments. The results suggest that much of the time that resident lobsters spend outside shelters is used to remain familiar with their constantly changing physical and social environment.
170 citations
TL;DR: The data indicate that factors in addition to substratum surface energy determine attachment of bryozoan larvae espe cially when bacterial films are present, and that bacterial extracel bubarmaterials may be involved.
Abstract: The effects of individual species of marine bacteria on the attachment ofbarvae ofthe bryozoan Bu gula neritina were examined in the laboratory. Bacteria, grown to mid-exponential phase and allowed to adsorb to polystyrene petri dishes, attached at densities of l06_ l0@cells cm2. Bryozoan attachment assays (30 mm) were used to compare the effects of adsorbed cells of three species of bacteria with unfilmed surfaces. Larvae permanently attached, at high percentages (65â€"94%), to unfilmed polystyrene, hydrophobic (i.e., bowwettability, bowsurface energy) control surfaces. This activity agrees with reports in the literature. Films ofindividual species of bacteria can influence bryozoan attachment. Three separate strains of the bacterial species Deleya marina inhibited attachment, but two other species of marine bacteria did not. Measurements indicated that all five bacteria tested differed in their cell-surface hydrophobic ity, but that their films were similar in that they were all highly wettable (i.e., high surface free energy). Our data indicate that factors in addition to substratum surface energy determine attachment of bryozoan larvae espe cially when bacterial films are present. Bacterial extracel bubarmaterials may be involved.
139 citations
TL;DR: Tolerance of hypoxia over 28 days at 30°C decreases in a series of crustaceans, and greater depression of metabolic rate oc curs in molluscs during anoxia exposure than occurs in Cal !
Abstract: Although some species of fish, crustaceans, and molluscs may behaviorally avoid hypoxic masses of small size and limited duration, others cannot. In a series of crustaceans, tolerance of hypoxia over 28 days at 30°C, decreases as follows: Eurypanopeus depressus (38 Torr = LC50)> Pa!aemonetespugio > Rhithropanopeus harrisii > Penaeus aztecus > Caiinectes sapidus (121 Torr = LC50).Caiinectes sapidus and E. depressus die during 12-hexposure to anoxia and their heat dissipation rates (quantified by microcalorimetry) are depressed in seawater at 25%air saturation (normoxia) to only 32 and 47% of their metabolic rate at normoxia. In contrast, starved Crassostrea virginica and Thais haemastoma are anoxia tolerant; their metabolic rates are depressed un der anoxia to 75%and 9%ofthe normoxic rate. Hypoxia tolerance is greater at 20°C than at 30°C for Penaeus az tecus and Crassostrea virginica, but no temperature effect on tolerance exists for Caiinectes sapidus. Hyp oxia tolerance varies inversely with salinity for Penaeus aztecus at 20° and 30°C and for Caiinectes sapidus at 30°C, but it varies directly with salinity at 20°C in Caii nectes sapidus. Greater depression of metabolic rate oc curs in molluscs during anoxia exposure (and is corre batedwith greater hypoxia tolerance) than occurs in Cal !inectes sapidus and Penaeus aztecus, which are not anoxia tolerant. Heavy mortality probably occurs in young Caiinectes sapidus and Penaeus aztecus and in
134 citations
TL;DR: Simultaneous calorimetry and respirometry showed that in response to declining oxygen tension (Po2), the rates of heat dissipation and oxygen uptake by oyster larvae are maintained independent of Po2 down to low Pc values (2 kPa for prodissoconch larvae and 8 k Pa for pediveliger and juveniles).
Abstract: The tolerance of Crassostrea virginica larvae to anoxia increases with developmental stage and body size. Median mortality times range from 11 h for prodissoconch larvae of 82 µm (shell length) to 51 h for pediveliger larvae of 312 µm, and 150 h for juvenile oysters. Simultaneous calorimetry and respirometry showed that in response to declining oxygen tension (Po2), the rates of heat dissipation and oxygen uptake by oyster larvae are maintained independent of Po2 down to low Pc values (2 kPa for prodissoconch larvae and 8 kPa for pediveliger and juveniles). Therefore, total energy metabolism is sustained mainly by aerobic metabolism down to 2 and 4 kPa for early larval stages and juveniles, respectively. Prodissoconch larvae maintain relatively high rates of heat dissipation under anoxic conditions (34% of normoxic rate), whereas pediveliger and juveniles lower their anoxic rates of heat dissipation to 3% of the normoxic rate. The ability to reduce rates of heat dissipation and thus conserve energy expend...
105 citations
TL;DR: Genetic variation from 8 polymorphic enzyme loci among 17 population samples of queen conch, Strombus gigas, exhibits similarity of allelic frequencies throughout the species distribution.
Abstract: Genetic variation from 8 polymorphic enzyme loci among 17 population samples of queen conch, Strombus gigas, exhibits similarity of allelic frequencies throughout the species distribution. Analyses...
96 citations
TL;DR: The reproductive biology of Plexuara A, a common but undescribed Caribbean gorgonian, was studied in the San Blas Islands, Panama, where oocytes were present in the polyps throughout the year, though a seasonal developmental cycle is evident.
Abstract: The reproductive biology of Plexuara A, a common but undescribed Caribbean gorgonian, was studied in the San Blas Islands, Panama. Oocytes were present in the polyps throughout the year, though a seasonal developmental cycle is evident. Early stage oocytes appeared at the base of the polyps in November. In January total egg volume per polyp began to increase and reached a maximum in early May. Total egg volume per polyp then decreased through the summer as mature eggs were released. Spawning occurred over a period of 4-7 days following each full moon in May, June, and July. Egg release was synchronous, starting at approximately 18:30 and lasting 90 minutes. Larval development is initiated just prior to or at the time of release. Initiation of larval development at the time of release without brooding is unknown for any gorgonian or scleractinian. Of 265 colonies examined from 6 reefs near San Blas Point, all but 3 contained gonads and were female. No male or hermaphroditic colonies have been found in the ...
89 citations
TL;DR: Delaying metamorphosis of C.forni cata does not appear detrimental, at least for the first few weeks ofjuvenile life, and there was no indication that delaying meetamorphosis reduced juvenile tolerance of tempera ture-salinity stress.
Abstract: Larvae of most marine invertebrates delay metamorphosis ifthey fail to contact an appropriate en vironmental stimulus. We conducted seven experiments with the slipper shell snail, Crepidulafornicata, to deter mine if delaying metamorphosis decreases juvenile fit ness. Larvae were reared in the laboratory at 25°C on the unicellular alga Isochrysis sp. (clone T-ISO, 18 X iO@ cells m1'), and were induced to metamorphose after long, medium, or short periods ofdelayed metamorpho sis. Long delay larvae were reared until they metamor phosed spontaneously in acid-cleaned glassware. Me dium and short delay larvae were induced to metamor phose with adult-conditioned seawater or 20 mM elevations ofKCl. Juveniles were subsequently reared for about one to two weeks at 25°C in the laboratory on a diet ofT-ISO. Delaying metamorphosis generally did not lower juvenile weight-specific feeding rates, increase ju venile weight-specific respiration rates, or lower juvenile shell or tissue growth rates, any of which effects would suggest that delaying metamorphosis reduces juvenile fitness. Moreover, there was no indication that delaying metamorphosis reduced juvenile tolerance of tempera ture-salinity stress. Delaying metamorphosis of C.forni cata does not appear detrimental, at least for the first few weeks ofjuvenile life.
86 citations
TL;DR: Estimates of the contribution that dissolved organic material in seawater could provide to larvae, showed that this pool of exogenous material could supply the missing energy.
Abstract: Larvae of the gastropod Haliotis rufescens are classified as “?�nonfeeding†because they cannot cap ture particulate foods. However, for only 1out of5 inde pendent cultures was a net decrease observed in dry or ganic weight during the complete period oflarval devel opment (5 to 7 days). In fact, there were net increases in dry organic weight from the oocyte (day 0) to the newly formed veliger larva (2-day-old). These weight increases during early development could be explained by in creases in the amounts of specific biochemical compo nents of the larvae, relative to oocytes. The metabolic rates oflarvae were measured (oxygen consumption) and used to compare (i) the required energy for development with (ii) the energy supplied from the catabolism of bio chemical reserves. This analysis revealed that the cost of development for larvae could not be explained by the rates of use of the energy stores initially present in the oocyte. Larvae, from two independent cultures, could only supply 25% or 71% oftheir energy requirements by the use of internal reserves. Larvae of H. ruftscens can not use particulate foods and, thus, this energy resource cannot be invoked. Estimates of the contribution that dissolved organic material in seawater could provide to larvae, showed that this pool of exogenous material could supply the missing energy. It is suggested that “?�nonfeeding†larvae can feed, but that their only avail
85 citations
TL;DR: This distribution and other evidence indicate that, besides its role in moral regulation of the pigmentary system, PDH may serve extra-pigmentary functions.
Abstract: This report summarizes recent work on the pigment-dispersing hormone (PDH) family, a set of re lated neuropeptides common to arthropods. The psi mary structures are known for the major form of PDH in several crustacean species (Pandalus borealis, Uca pugi!ator, Cancer magister, Penaeus aztecus, Procam barus c!arkii) and for related pigment-dispersing factors from two insects (Acheta domesticus, Romalea micro ptera). In this peptide family, the amino acid chain length (18 residues), termini (N-terminal Asn, C-termi nal Ala-NH2), and at least 50% ofthe sequence are con served. Synthetic analogs have been used to analyze the structure-activity relations ofPDH, leading to: an evalu ation of the role of specific residues; a tentative identifi cation of the message sequence; and the preparation of stable and superpotent analogs including tyrosinated an alogs for radioiodination. An enzyme-linked immuno sorbant assay (ELISA) has been developed for @9-PDH. Antisera raised against a-PDH and f@-PDH were used to determine the distribution of PDH. This distribution and other evidence indicate that, besides its role in hu moral regulation of the pigmentary system, PDH may serve extra-pigmentary functions. The functions of the PDH-related peptides in insects are unknown.
TL;DR: The discovery of insulin-related peptides in insects and molluscs substantiates the evidence for an early origin and widespread evolution of the insulin superfamily.
Abstract: Insulin and related peptides are key hormonal integrators of growth and metabolism in vertebrates. Recently, the amino acid and DNA sequences of insulin-related peptides in invertebrates have become available. The discovery of such peptides in insects and molluscs substantiates the evidence for an early origin and widespread evolution of the insulin superfamily.In the silkworm Bombyx (Insecta) the prothoracicotropic hormones (bombyxins I, II, and III; previously called PTTH) are produced in the brain and may stimulate synthesis and release of ecdysone; thus they play a central role in insect development. In the freshwater snail Lymnaea (Mollusca), a growth stimulating hormone (molluscan insulin-related peptide; MIP) is produced in the brain, and two other insulin-related peptides are produced in the digestive system. The MIPs are involved in body and shell growth and energy metabolism. The finding that bombyxin and MIP are involved in the control of growth fits with ideas being developed in the vertebrate...
TL;DR: The seasonal occurrence, population dynamics, feeding, growth, reproduction, and timing of planular deposition was determined for a semelparous annual population of Cyanea medusae in the Niantic River estuary, Connecticut, which was sampled for 14 years.
Abstract: The seasonal occurrence, population dynamics, feeding, growth, reproduction, and timing of planular deposition was determined for a semelparous annual population of Cyanea medusae in the Niantic River estuary, Connecticut, which was sampled for 14 years. The annual pattern was highly predictable. Their ephyrae appear shortly after ice-out in late February, medusae with gonads occur in late April-early May, and are reproductive (bearing planulae on their oral folds) by late May-early June. At this time (early to mid-June), the medusae deteriorate, disappearing from the plankton in late June-early July. Population size, similarly, exhibits small variation, showing only a 5-fold difference in anbundance. With deterioration, the frequency of feeding medusae declines; otherwise, they are opportunistic predators on seasonally numerous zooplankton, including fish. Growth shows two phases: first, a three month period of rapid exponential growth when medusae mature; and second, a one and one half month period of decline in average size of individuals as the larger medusae die. Medusae exhibit a sequence of "organ" loss prior to death: first, the tentacles, then the oral folds, and last, the gonads. Coincident with the disappearance of these organ-deficient medusae from the water column, their planulae first appear attached to shells in the benthos. The deterioration of medusae, and in particular the loss of planulae-bearing oral folds, may be requisite for the mass release of their planulae.
TL;DR: Stages in the development of the vestimentiferan Ridgeia sp.
Abstract: Stages in the development of the vestimentiferan Ridgeia sp., based on lengths of preserved specimens processed for scanning electron microscopy, were examined. Features of the nervous system and trophosome of Riftia pachyptila were studied by light, scanning-, and transmission-electron microscopy. Development proceeds from a trochophore-type larva with an anterior prototrochal ciliary ring and a posterior assemblage of transient larval setae, through intermediate stages, some of which lack endosymbiotic bacteria but all of which display additional transient features such as larval branchial filaments, a ventral medial process, and digestive tract, to a young juvenile stage that possesses endosymbiotic bacteria and exhibits the morphology characteristic of adult vestimentiferans. Larval branchial filaments are resorbed in later developmental stages and replaced by paired rows of ciliated branchial filaments with pinnules. The larval gut is divisible into foregut, midgut, and hindgut regions based on cytol...
TL;DR: The results suggest that the shallow cove in Buzzards Bay, Massachusetts is used as a refuge for injured mature males, and overall activity was correlated more with molting (premolt activity peak) than with temperature.
Abstract: We report the results of a nonmanipulative field study of the lobster, Homarus americanus, using long-term behavioral observations of marked individuals. We observed a freely mobile population in an open shallow cove habitat (50 m x 150 m) in Buzzards Bay, Massachusetts. Lobsters larger than 50 mm carapace length (CL) living in or entering the study site were marked individually (334 during the 19-month study). Without further manipulation, the animals were observed as long as they remained in the study site. Of the marked animals, 48% were transient, i.e., seen only once. The population was made up largely of subadults with a sex ratio of M:F = 1.8. The summer and fall resident population consisted of about 30 animals. Maximum residency was over 13 months. Half of the resident population, mostly small animals (50-59 mm CL), apparently overwintered in the site. A distinct peak in molting occurred both years in the spring at a water temperature of about 15°C. Injured animals were seen frequently (26% of the population) including a high proportion of mature resident males missing claws. Most other injured animals were transient (60%). These results suggest that the shallow cove is used as a refuge for injured mature males. Activity was strictly nocturnal with a peak 1-3 h after sunset and declining through the night. Activity levels were equal for both sexes. Overall activity was correlated with seasonal variations in water temperature (0-24°C). At times, activity was correlated more with molting (premolt activity peak) than with temperature. Behavioral interactions in this population are described in a companion paper (Karnofsky et al., 1989).
TL;DR: Maximal rates of carbon fixation were documented in incubations in dilute Riftia blood, which protects the symbionts from the inhibitory effects of free sulfide and oxygen while providing them with an abundant pool of both substrates, bound by the v...
Abstract: Preparations of trophosome tissue from Riftia pachyptila containing viable endosymbiotic bacteria were incubated with several substrates under a variety of conditions to characterize the symbionts physiologically. Of all the potential substrates tested, only sulfide stimulated carbon fixation by the trophosome preparations; neither hydrogen, ammonia, nor thiosulfate were effective. Trophosome preparations did not oxidize 14C-methane to either 14C-organic compounds or 14CO2, nor did they reduce acetylene under the conditions tested. Carbon fixation by the endosymbionts appears barotolerant. The symbionts require both sulfide and oxygen to fix carbon through autotrophic pathways, but are inhibited by free oxygen and by sulfide concentrations in the 300 µM range. Maximal rates of carbon fixation were documented in incubations in dilute Riftia blood, which protects the symbionts from the inhibitory effects of free sulfide and oxygen while providing them with an abundant pool of both substrates, bound by the v...
TL;DR: It was found that the upper and lower limits of the opti mal temperature range for embryogenesis in each animal were species-specifically determined, and that the range of water temperature during the breeding season was within this optimal temperature range.
Abstract: Three species of sea urchin, Hemicentrotus puicherrimus, Anthocidaris crassispina, and Hemicen trotus depressus, inhabit the tidal areas around the Mi saki Marine Biological Station, on the Pacific coast of Japan. These sea urchins have different breeding seasons and hence their embryos show differences in tempera ture sensitivity. In this study, differences in the tempera ture dependence oftheir embryogenesis were examined. It was found that the upper and lower limits of the opti mal temperature range for embryogenesis in each animal were species-specifically determined, and that the range ofseawater temperature during the breeding season was within this optimal temperature range. A quasi-linear re lationship was obtained between temperature and rela tive developmental velocity, which was defined as the ra tio against the maximal velocity attained at the highest temperature within the optimal temperature range. Based on this result, a form ofgraphical analysis was de vised to represent the differences in species-specific de velopmental temperature sensitivity. The physiological and ecological significance of species-specific tempera ture sensitivity was also discussed.
TL;DR: The distribution and abundance of Centropages hamatus eggs in the upper 5 cm of the sea-bottom of the Alligator Harbor region, Florida, was determined in this paper, where the hatching of these eggs at 4, 10, 15, 19,...
Abstract: The distribution and abundance of Centropages hamatus eggs in the upper 5 cm of the sea-bottom of the Alligator Harbor region, Florida, was determined. The hatching of these eggs at 4, 10, 15, 19, ...
TL;DR: Considering larval sinking rates and normal environmental salinity gradients, larvae of both species can respond to rates and amounts of salinity increase in their environment and the ascent response may be important for keeping larvae up in the water column and reducing the likelihood that they will encounter the bottom.
Abstract: The ontogeny of behavioral responses of larvae of the crabs Rhithropanopeus harrisii and Neopanope sayi to rates of change in salinity were analyzed with a video system. A salinity increase evoked an ascent in both species. For R. harrisii the threshold rate of increase was 1.1 x 10-3 ppt s-1 for the first and last zoeal stages and changed little with acclimation salinity. N. sayi larvae were more sensitive, as thresholds were 2.8 x 10-4 ppt s-1 for Stage I zoeae and 7.0 x 10-4 ppt s-1 for Stage IV. This difference in sensitivity may relate to the magnitude of salinity gradients in the estuarine/coastal areas inhabited by the larvae. At threshold rates of salinity increase the absolute amount of change before a response was lower for Stage I zoeae (0.09-0.11 ppt) than Stage IV zoeae (0.21-0.29 ppt) for both species. Decreases in salinity did not induce the expected descent response in either species at rates up to 4.7 x 10-2 ppt s-1. The different responses in a salinity gradient may have resulted because the rate threshold and absolute amount of change before a response to a salinity increase were below those for a salinity decrease. Considering larval sinking rates and normal environmental salinity gradients, larvae of both species can respond to rates and amounts of salinity increase in their environment. The ascent response may be important for keeping larvae up in the water column and reducing the likelihood that they will encounter the bottom.
TL;DR: Eggcoats are compared among ma jor deuterostome groups, and the results imply that the ancestral chordate may have been an unspecialized ap pendicularian.
Abstract: A method for artificial fertilization of lance let eggs is described, and the egg coats are studied for the first time by transmission electron microscopy. Large, ovarian oocytes and spawned, unfertilized eggs (which are about 140 @tm in diameter) are surrounded by a coarsely granular vitelline layer about 1 @m thick and a jelly layer a few micrometers thick. The egg cortex is crowded with a monolayer ofcortical granules, each with an average diameter ofapproximately 3.5 sm. About 20 to 30 5 after insemination, a cortical reaction occurs al most simultaneously over the entire eggsurface. The cor tical granules undergo exocytosis, and part of their con tent evidently forms a dense layer 30 nm thick against the inside of the vitelline layer: both layers together con stitute the fertilization envelope, which begins elevating from the eggsurface. By 80 s after insemination, the jelly layer has disappeared, and beneath the fertilization enve lope the bulk ofthe ejected cortical granule material has become organized into a hyaline layer with a finely fi brogranular consistency. By 20 mm after insemination, the perivitelline space between the fertilization envelope and the egg surface has attained its maximum width of roughly 150 jim, and both the hyaline layer and the vitel line layer component of the fertilization envelope are much attenuated and remain so until hatching about 9 h after insemination. Eggcoats are compared among ma jor deuterostome groups, and the results imply that the ancestral chordate may have been an unspecialized ap pendicularian.
TL;DR: It is concluded that the LGF shadow-sensitivity is localized in posterior segments, and electron microscopic observations demonstrating the presence of candidate photoreceptor cells in the epidermis of posterior segments support this idea.
Abstract: A novel escape reflex involving the posterior end of a freshwater oligochaete worm, Lumbriculus variegatus, is described. Electrophysiological recordings and videotape analysis from submersed, free...
TL;DR: This study documents early development and metamorphosis in P. parvispinus and considers the evolution of features unusual in echinoid ontogeny, which are characteristic of other direct developing echinoids and probably functional modifications for altered developmental mode.
Abstract: Development in the Australian sea urchin Phyllacanthus parvispinus (Echinoidea: Cidaroidea) is of interest because it has a highly modified, lecithotrophic larva, and because it belongs to an echinoid group whose development has been little studied. This study documents early development and metamorphosis in P. parvispinus and considers the evolution of features unusual in echinoid ontogeny. Some features, such as lack of a vestibule, occur in other cidaroids, and are likely a product of ancestry. Other unusual features, such as larger gametes, an equal fourth cleavage, a wrinkled blastula, and accelerated development of the adult rudiment, are characteristic of other direct developing echinoids, and are probably functional modifications for altered developmental mode. Since the Cidaroidea form the sister group to the more derived Euechinoidea, cidaroid development is critical in assessing the phylogeny of ontogeny among echinoids. The distribution of developmental features among extant echinoids suggests...
TL;DR: In this article, the effect offlow regime on the ability of the hydroid Obelia longissima to capture plankton was ex amined in a laboratory flume and a wave tank, showing that the proportion of the gastrozooids with tentacles successfully capturing food in a fixed amount of time is significantly greater in oscillating flow than in unidirectional flow at the same average velocity and particle flux.
Abstract: The effect offlow regime on the ability of the hydroid Obelia longissima to capture plankton was ex amined in a laboratory flume and a wave tank. Feeding effectivenessâ€"the proportion of the gastrozooids with tentacles successfully capturing food in a fixed amount of timeâ€".-is significantly greater in oscillating flow than in unidirectional flow at the same average velocity and particle flux. Thus quantitative feeding studies in uni directional flow may seriously underestimate feeding in the field ifflow in the natural habitat is unsteady. Increas ing colony bushiness (weight/colony length) decreases feeding effectiveness in uni-directional and low fre quency oscillating flow, but not in high frequency oscil batingflow. Longer colonies (0.083 m) show significantly lower feeding effectiveness than short (0.033 m) colonies. This decrease in feeding effectiveness with increasing cob ony length and bushiness is offset by a rapid increase in polyp number with increasing colony length.
TL;DR: Tetrodotoxin (TTX) producing bacteria have been isolated from four species of planktonic chaetognaths: Flaccisagitta lyra, Parasagitta elegans, Zonosagitta nagae, and Eukrohnia hamata and it is suggested that this bacterium lives associated with these Chaetognath species and is responsible for the production of the TTX.
Abstract: Tetrodotoxin (TTX) producing bacteria have been isolated from four species of planktonic chaetognaths: Flaccisagitta lyra, Parasagitta elegans, Zonosagitta nagae, and Eukrohnia hamata. TTX producti...
TL;DR: This paper describes the development of a suitable biotechnology to cryopreserve the spermatophores of the edible crab Scylla serrata in a viable condition and finds that at –4°C, the TCA-soluble total free sugars increased in correspondence with a decline in the bound sugars, suggesting that the latter may be use for sperm production.
Abstract: This paper describes the development of a suitable biotechnology to cryopreserve the spermato- phores of the edible crab Scylla serrata in a viable condi- tion. Three temperatures (-4?C, -79?C, and - 196?C) were chosen to preserve the spermatophores and seminal plasma, collected from the middle region of vas deferens of mature male crabs, for 30 days. Sperm viability was determined by the eosin-nigrosin dye exclusion method, as applied to entire spermatophores. Of the three temper- atures tested, the maximum percentage of sperm viabil- ity was obtained at -196?C, whereas it significantly de- creased at -4?C. Biochemical alterations of the major substrates such as proteins, carbohydrates, and lipids, as well as the enzyme Lactate Dehydrogenase (LDH) oc- curred only at -4'C, reflecting their use in the metabolic activities of the spermatozoa contained within the sper- matophores. At -4?C, the TCA-soluble total free sugars increased in correspondence with a decline in the bound sugars, suggesting that the latter may be used rapidly dur- ing sperm storage. Our data also suggest that, at -79?C and - 196?C, the frozen spermatozoa retain viability but do not exhibit metabolic activity. To investigate the role of cryoprotectants in prevent- ing damage to the sperm cells/spermatophores during cryopreservation, four cryoprotectants, glycerol, di- methyl sulfoxide (DMSO), trehalose, and DMSO + tre- halose combination, were tested. Using the phosphate buffer as the standard diluent, glycerol gave the best re- sult. When used alone, trehalose gave only a low sperm survival, but in combination with DMSO, it gave an in- creased viability that equalled the result with glycerol.
TL;DR: Transport rates of amino acids were deter mined for larvae of different ages of the echiuran worm Urechis caupo, the gastropod Haliotis ruftscens, the bi valve Crassostrea gigas, and the sea urchin Strongylo centrotus purpuratus to show an in crease in the transport rate of amino acid during deveb opment.
Abstract: Transport rates of amino acids were deter mined for larvae of different ages of the echiuran worm Urechis caupo, the gastropod Haliotis ruftscens, the bi valve Crassostrea gigas, and the sea urchin Strongylo centrotus purpuratus. All larval forms showed an in crease in the transport rate of amino acids during deveb opment. Trochophores of U. caupo increased their rate of net flux for each of 5 amino acids (100 nM each) by a factor of 1.6 and 2.2 during 1â€"3 days and 4â€"8 days, respectively, for two independent cultures. In H. rufes cens, the maximum transport capacity (Jmax) for alanine increased 3-fold during the 24 h required for the trocho phore to develop into a veliger. In C. gigas veligers, there was a 9-fold increase in the maximum transport capacity for alanine during larval development from an 80 @tm to a 300 sm larva. In sea urchins, the prism-stage larvae (2- day-old) had an alanine transport system with a K@ of 1.9 @tM and a Jmaxof 8. 1 pmol larva'h'. The kinetics of alanine transport in the pluteus-stage (4-day-old) were best described by two systems (System I: K1 = 1.0 zM with a imaxof5.6 pmol larva'h'; System II: K@ = 132.0 @.tM with a Jmaxof 8.4 pmol larva'h'). In larvae of C. gigas, the relationship between the rate ofalanine trans port and body size was described by the equation, bog Jmax (pglarva'h') = 1 .6894(X) + (â€"0.5937), where X is the shell length in @tm. It is illustrated that the albometric increase in respiration rates, during the growth of bivalve
TL;DR: Revue chez les arthropodes des fonctions sur differents organes (muscles alaires, tissu adipeux) des hormones adipocinetiques, considerations sur l'evolution de cette famille de peptides.
Abstract: Revue chez les arthropodes des fonctions sur differents organes (muscles alaires, tissu adipeux) des hormones adipocinetiques. Comparaison interspecifique de la sequence en acides amines. Considerations sur l'evolution de cette famille de peptides
TL;DR: Haminoea callidegenita Gibson and Chia (1989) has a pattern of development similar to that of other lecithotrophic opisthobranchs, except for the stage at hatching, and egg mass jelly also induces metamorphosis in hatched veligers.
Abstract: Haminoea callidegenita Gibson and Chia (1989) has a pattern of development similar to that of other lecithotrophic opisthobranchs, except for the stage at hatching. In this species, both veligers and juveniles hatch from each egg mass. The percent of each hatching stage was variable among masses, with most masses having 30 to 50% of total hatchlings emerging as veligers. Both veligers and juveniles emerge throughout the entire hatching period (lasting 3-11 days), although the percentage of veligers decreases during this period. Encapsulated embryos cultured without egg mass jelly had approximately 80% of the total hatchlings emerging as veligers. Separated embryos cultured in the presence of egg mass jelly pieces hatched with percentages of veligers similar to that observed in intact egg masses, suggesting the possibility of a diffusible compound present in the jelly mass that induces intracapsular metamorphosis. Egg mass jelly also induces metamorphosis in hatched veligers. A juvenile and adult food sour...
TL;DR: An extensive gelatinous material occupies the primary body cavity of larval echinoderms (auricu laria, bipinnaria, ophiopluteus, and echinopluteus).
Abstract: An extensive gelatinous material occupies the primary body cavity of larval echinoderms (auricu laria, bipinnaria, ophiopluteus, and echinopluteus) and hemichordates (tornaria). Its presence and its recovery of shape following application and release of force were demonstrated by dissection of larvae in a suspension of sumi ink. A gel in the primary body cavity explains struc tures that occur in all ofthese five larval forms: (1) con cave body surfaces bounded by thin epithelia and (2) muscles unopposed by other muscles. A gel filled pri mary body cavity invalidates deductions of morphoge netic mechanisms that assume a fluid filled cavity, an as sumption implicit in many models of blastulation, gas trulation, and movement of mesenchyme cells. A gelatinous primary body cavity permits body plans and morphogenetic processes not possible with a fluid filled cavity and permits development oflarge larvae with little cellular material. The taxonomic distribution ofgebfilled body cavities is not known, but gel filled cavities are pos sible wherever fluid motion has not been demonstrated or is not a functional necessity.
TL;DR: The design and utilization of a small (16 g in air, 6 g in water) ultrasonic transmitter for animal tracking and bio-telemetry of muscle activity are described, the first use of such devices to telemeter a specific behavior from a free-ranging marine predator.
Abstract: The design and utilization ofa small (16 g in air, 6 g in water) ultrasonic transmitter for animal track ing and bio-telemetry of muscle activity are described. To our knowledge this is the first use of such devices to telemetera specific behavior(ingestion) from a free-rang ing marine predator. The transmitter produces regularly recurring short tracking pulses, and bongpulses triggered by the action potentials ofa muscle. Pulses are transmit ted through conductive estuarine water by a piezoelectric ring transducer at a frequency of about 75 KHz. The preparation of a subject animal, insertion of electrodes, and attachment of the transmitter are described for the telemetry of mandibular muscle contraction in the blue crab. The transmitter provides a signal that corresponds unequivocally with feeding activity and allows enumera tion of bites required to consume a food item. Number of bites, and feeding time, are both positively correlated with the size of the prey specimen. As a test of the tech nique's feasibility, a blue crab was equipped with one of the transmitters and released in a subestuary of Chesa peake Bay. The crab was tracked continuously for 96 hours while every contraction ofthe mandibular muscle was recorded. The crab traveled 4000 m along the subes tuary at an average speed of 12 rn/h, but showed periods of rapid movement of up to 325 m/h. The crab fed 2â€"7 times per day, with a feeding bout comprising 15â€"2750 bites. The limited data did not indicate that either move ment or feeding exhibit a die! or tidal cycle.