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182 records returned

Predator-induced larval cloning in the sand dollar Dendraster excentricus: might mothers matter?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study tested the hypothesis that cloning in D. excentricus plutei is maternally influenced. Plutei from three half-sibling larval families (different mothers, same father) were exposed to fish mucus for 9 days during early development. Cloning was inferred in a percentage of plutei from each family; however, the rate and success of cloning differed significantly among the larval half-siblings. Unexpectedly, all mucus-treated plutei were smaller and developmentally delayed when compared to all plutei reared in the absence of a mucus stimulus. Thus, while the results from this study support the hypothesis of an influenc...
Source: The Biological Bulletin - October 1, 2009 Category: Biology Authors: Vaughn D Tags: Biol Bull Source Type: journals

Subtidal benthic heterogeneity: flow environment modification and impacts on marine algal community structure and morphology.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We examined the impact of macroscopic benthic structure on the maximum flow speeds and the corresponding macroalgal community cover and morphological diversity observed in response to microhabitats in both exposed and sheltered near-shore sites. Flow speeds were reduced by a factor of 2 within crevices and also in the flow-shadow of protruding rock substrate when compared to neighboring unobstructed planar microhabitats. Algal communities within crevices and in the wake of protrusions were found to have greater cover of foliose red algal species compared to horizontal microhabitats in exposed sites, but reduced cover of th...
Source: The Biological Bulletin - October 1, 2009 Category: Biology Authors: Ferrier GA, Carpenter RC Tags: Biol Bull Source Type: journals

Lectins associated with the feeding organs of the oyster Crassostrea virginica can mediate particle selection.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study confirms the presence of lectins in mucus that covers the feeding organs of oysters and suggests a new concept with regard to particle processing by suspension-feeding bivalves: specific interactions between carbohydrates on the surface of particles and lectins within the mucus mediate the selection and rejection processes. PMID: 19875818 [PubMed - in process] (Source: The Biological Bulletin)
Source: The Biological Bulletin - October 1, 2009 Category: Biology Authors: Espinosa EP, Perrigault M, Ward JE, Shumway SE, Allam B Tags: Biol Bull Source Type: journals

Electroretinographic analysis of night vision in juvenile pacific bluefin tuna (Thunnus orientalis).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We used electroretinogram recordings to investigate visual function in the dark-adapted eyes of the juvenile scombrid fishes Pacific bluefin tuna (Thunnus orientalis) and chub mackerel (Scomber japonicus) and the carangid fish striped jack (Pseudocaranx dentex). Despite the fast swimming speed of the Pacific bluefin tuna, analysis of flicker electroretinograms showed that visual temporal resolution in this species was inferior to that in chub mackerel. Peak wavelengths of spectral sensitivity in Pacific bluefin tuna and striped jack were 479 and 512 nm, respectively. The light sensitivity of Pacific bluefin tuna was co...
Source: The Biological Bulletin - October 1, 2009 Category: Biology Authors: Matsumoto T, Ihara H, Ishida Y, Okada T, Kurata M, Sawada Y, Ishibashi Y Tags: Biol Bull Source Type: journals

Dynamic modification of oral innervation during metamorphosis in Branchiostoma belcheri, the oriental lancelet.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The oral apparatus in lancelets undergoes a remarkable modification during larval development, especially during metamorphosis, when the oral innervation is radically altered. The larval mouth opens on the left side at the early larval stage, and a peripheral nerve network, the oral nerve ring (ONR), develops around it. The ONR enlarges as the mouth expands caudally, eventually receiving fibers from nerves as far back as the tenth on the left side. The mouth shrinks during metamorphosis, and with this change the ONR regresses; the posterior sixth to tenth nerves become freed from the connection with the ONR, whereas th...
Source: The Biological Bulletin - October 1, 2009 Category: Biology Authors: Kaji T, Shimizu K, Artinger KB, Yasui K Tags: Biol Bull Source Type: journals

Environmental and physiological controls of blue crab avoidance behavior during exposure to hypoxia.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Generalizing the impacts of hypoxia on aquatic animal populations is difficult due to differences in behavioral and physiological responses among individuals as well as varying hydrodynamics of hypoxic events. Information on which environmental cues animals use to avoid hypoxia and how abiotic covariates and physiology influence avoidance behavior is lacking. Our laboratory flume studies quantified the interacting effects of hydrography (dissolved oxygen [DO], temperature, and salinity), hydrodynamics (rate of DO decline and current speed), and physiological state on avoidance behaviors of blue crabs (Callinectes sapid...
Source: The Biological Bulletin - October 1, 2009 Category: Biology Authors: Bell GW, Eggleston DB, Noga EJ Tags: Biol Bull Source Type: journals

Gill Development and its functional and evolutionary implications in the blue mussel Mytilus edulis (Bivalvia: Mytilidae).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Study of gill development in bivalve larvae and postlarvae provides information on the evolution of this organ and feeding mechanisms of early stages. Scanning electron microscopy was used to document the development of the filibranch homorhabdic gill in hatchery-reared larval, postlarval, and juvenile Mytilus edulis. Four key stages were identified during gill development: (1) transfer of the particle collection function from velum to gill at metamorphosis, with subsequent elongation of the gill filaments to form a gill basket, with complete frontal ciliation; (2) reflection of the inner demibranchs, and transition to...
Source: The Biological Bulletin - October 1, 2009 Category: Biology Authors: Cannuel R, Beninger PG, McCombie H, Boudry P Tags: Biol Bull Source Type: journals

Hunchback-like protein is expressed in cleavage blastomeres, gastrula epithelium, and ciliary structures in gastropods.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report the expression of Hunchback (Hb)-like protein during embryonic and larval development in two caenogastropods, Crepidula fornicata and Ilyanassa obsoleta. During the cleavage stages of these species, Hb-like protein is uniformly expressed in micromere and macromere nuclei. At gastrulation, gastropod Hb-like protein is expressed in the surface epithelium that undergoes epiboly. During organogenesis, gastropod Hb-like protein is expressed in the developing ciliated structures associated with feeding and locomotion. We find no detectable gradient or regionalization of Hb-like protein in gastropod embryos or larvae th...
Source: The Biological Bulletin - October 1, 2009 Category: Biology Authors: Dean D, Himes CM, Behrman E, Savage RM Tags: Biol Bull Source Type: journals

Ionizing radiation induces apoptotic signal through protein kinase Cdelta (delta) and survival signal through Akt and cyclic-nucleotide response element-binding protein (CREB) in Jurkat T cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Although ionizing radiation induces a loss of proliferative capacity as well as cell death by apoptosis and necrosis, cells can oppose the damaging effects by activating survival signal pathways. Here we report the effect of 1.5- and 6-Gy doses of ionizing radiation on apoptotic protein kinase Cdelta (PKCdelta) and survival cyclic-nucleotide response element-binding protein (CREB) signal in Jurkat T cells. Cell cycle analysis, performed by flow cytometry, showed a significant G2M arrest 24 h after exposure to 6 Gy. This arrest was accompanied by dead cells, which increased in number up to 7 days, when cell viability wa...
Source: The Biological Bulletin - October 1, 2009 Category: Biology Authors: Cataldi A, Di Giacomo V, Rapino M, Zara S, Rana RA Tags: Biol Bull Source Type: journals

A plea for basic science.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19679717 [PubMed - in process] (Source: The Biological Bulletin)
Source: The Biological Bulletin - July 31, 2009 Category: Biology Authors: Olds JL Tags: Biol Bull Source Type: journals

Cycliophoran dwarf males break the rule: high complexity with low cell numbers.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Complexity of metazoan bodyplans is commonly assumed to be correlated to the absolute number of cells and the number of cell types present in a species (1). Sexually mature individuals of the smallest free-living animals have a minimum of several hundred somatic cells, and only secondarily simplified parasitic or commensal species range below this threshold. Males of the two hitherto described representatives of the phylum Cycliophora (2), with a body length of about 40 mum, are among the smallest existing free-living metazoans, yet they exhibit an amazingly complex bodyplan. Herein, we show that only a few dozen cells...
Source: The Biological Bulletin - July 31, 2009 Category: Biology Authors: Neves RC, Sørensen KJ, Kristensen RM, Wanninger A Tags: Biol Bull Source Type: journals

Nutrient Uptake by Marine Invertebrates: Cloning and Functional Analysis of Amino Acid Transporter Genes in Developing Sea Urchins (Strongylocentrotus purpuratus).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Transport of amino acids from low concentrations in seawater by marine invertebrates has been extensively studied, but few of the genes involved in this physiological process have been identified. We have characterized three amino acid transporter genes cloned from embryos of the sea urchin Strongylocentrotus purpuratus. These genes show phylogenetic proximity to classical amino acid transport systems, including Gly and B0+, and the inebriated gene (INE). Heterologous expression of these genes in frog oocytes induced a 40-fold increase in alanine transport above endogenous levels, demonstrating that these genes mediate...
Source: The Biological Bulletin - July 31, 2009 Category: Biology Authors: Meyer E, Manahan DT Tags: Biol Bull Source Type: journals

Formation of the apical flaps in nematocysts of sea anemones (cnidaria: actiniaria).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Using scanning and transmission electron microscopy, we studied formation of the structure at the apical end of sea anemone nematocysts through which the tubule everts at discharge. In anemones of the genus Metridium, we found that each of the three solid triangular apical flaps comprises two layers that are continuous with those of the capsule wall: the electron-lucent inner layer is bound to the electron-dense outer layer. The two-layer structure is obvious in some discharged capsules in which, perhaps due to fixation, the layers part at the flap's periphery. Before the nematocyst discharges, a channel leads from a p...
Source: The Biological Bulletin - July 31, 2009 Category: Biology Authors: Reft AJ, Westfall JA, Fautin DG Tags: Biol Bull Source Type: journals

Ultrastructure of the retinal synapses in cubozoans.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cubomedusae (box jellyfish) are well known for strong directional swimming, rapid responses to visual stimuli, and complex lensed eyes comparable to those of more advanced multicellular animals. They possess a total of 24 eyes that are of four morphologically different types, yet little is known about the neural organization of their eyes. The eyes are located on ganglion-like structures called rhopalia. Each of the four rhopalia contains an upper and a lower lensed eye (with a cornea, lens, and retina), two pit ocelli, and two slit ocelli. Transmission electron microscopy was used to examine the synaptic morphology of...
Source: The Biological Bulletin - July 31, 2009 Category: Biology Authors: Gray GC, Martin VJ, Satterlie RA Tags: Biol Bull Source Type: journals

Serotonergic modulation of crayfish hindgut.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The crayfish hindgut is a morphologically differentiated tube that varies along its length in the distribution of muscles and glands, contractile properties, serotonergic innervation, patterns of 5-HT receptor expression, and sensitivity to serotonin (5-HT). Anatomical differences divide the hindgut into five distinct segments along its length. Spontaneous pulsatile contractions produced by the isolated hindgut decrease in force and increase in frequency along the anterior-posterior axis. Central input to the hindgut comes from a large cluster of 5-HT-immunoreactive neurons in the terminal abdominal ganglion that form ...
Source: The Biological Bulletin - July 31, 2009 Category: Biology Authors: Musolf BE, Spitzer N, Antonsen BL, Edwards DH Tags: Biol Bull Source Type: journals

Species-Specific Vulnerability of Benthic Marine Embryos of Congeneric Snails (Haminoea spp.) to Ultraviolet Radiation and Other Intertidal Stressors.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We used field surveys and multi-factorial experiments to examine synergistic effects of ultraviolet radiation (UVR) and low tide conditions on the embryonic mortality of two bubble-shell snail species that deposit gelatinous egg masses in intertidal mudflats: Haminoea zelandiae from New Zealand, and Haminoea vesicula from Washington, USA. Egg masses of both species were predominantly found in shallow pools at low tide, and a substantial proportion of both were found in sunny as well as shaded microhabitats. Both exposure to sun and desiccation led to increased embryonic mortality for naturally deposited egg masses of H...
Source: The Biological Bulletin - July 31, 2009 Category: Biology Authors: Russell J, Phillips N Tags: Biol Bull Source Type: journals

Linking Thermal Tolerances and Biogeography: Mytilus edulis (L.) at its Southern Limit on the East Coast of the United States.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study we determined the upper lethal thermal limits, for both air and water, of the blue mussel Mytilus edulis via laboratory experiments. Tolerances vary seasonally, with a difference between media of 0.7 degrees C in June and 4.8 degrees C in November, as well as a decrease with multiple exposures. Measured lethal limits were then compared to field measurements of environmental temperature and concurrent measurements of mortality rates. Field results indicate that mortality in the intertidal occurs at rates expected from laboratory responses to elevated temperature. Hindcasts, retrospective analyses of historical...
Source: The Biological Bulletin - July 31, 2009 Category: Biology Authors: Jones SJ, Mieszkowska N, Wethey DS Tags: Biol Bull Source Type: journals

Estuarine-scale genetic variation in the polychaete hobsonia Florida (ampharetidae; annelida) in long island sound and relationships to pleistocene glaciations.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We examined fine-scale patterns of genetic differentiation among populations in the ampharetid polychaete Hobsonia florida in Long Island Sound (LIS) relative to its life-history traits and the geologic history of the region. Mitochondrial DNA sequencing of cytochrome oxidase I (COI) revealed 15 unique haplotypes among four populations in LIS and two outgroups. Populations in LIS exhibited the greatest haplotypic diversity compared to outgroup populations. Analysis of molecular variance revealed a highly significant level of genetic heterogeneity (P < 0.001) in LIS, with almost 40% of the variance attributed to differen...
Source: The Biological Bulletin - July 31, 2009 Category: Biology Authors: Olson MA, Zajac RN, Russello MA Tags: Biol Bull Source Type: journals

Idiopathic Lesions and Visual Deficits in the American Lobster (Homarus americanus) From Long Island Sound, NY.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In 1999, a mass mortality of the American lobster (Homarus americanus) occurred in western Long Island Sound (WLIS). Although the etiology of this event remains unknown, bottom water temperature, hypoxia, heavy metal poisoning, and pesticides are potential causal factors. Lobsters from WLIS continue to display signs of morbidity, including lethargy and cloudy grey eyes that contain idiopathic lesions. As the effect of these lesions on lobster vision is unknown, we used electroretinography (ERG) to document changes in visual function in lobsters from WLIS, while using histology to quantify the extent of physical damage....
Source: The Biological Bulletin - July 31, 2009 Category: Biology Authors: Magel CR, Shields JD, Brill RW Tags: Biol Bull Source Type: journals

Biological bulletin virtual symposium: biology of marine invertebrate larvae.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19556588 [PubMed - in process] (Source: The Biological Bulletin)
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Emlet RB, Maslakova SA, Shanks AL, Young CM Tags: Biol Bull Source Type: journals

How did indirect development with planktotrophic larvae evolve?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The two main types of theories for the evolution of the biphasic life cycles in marine invertebrates are discussed. The "intercalation" theories propose that the larval stages (planktotrophic or lecithotrophic) have evolved as specializations from the ancestral, direct life cycle. The opposing "terminal addition" theories propose that the ancestor was holopelagic and that the adult stage was added to the life cycle with the pelagic stage retained as a planktotrophic larva. It is emphasized that theories based on hypothetical ancestors that were unable to feed must be rejected. This applies to planula theories based on ...
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Nielsen C Tags: Biol Bull Source Type: journals

Molluscan larvae: pelagic juveniles or slowly metamorphosing larvae?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Asking the right questions about evolution of development, larval morphology, and life history requires knowledge of ancestral state. Two hypotheses dominate current opinion about the ancestral life cycle of bilaterians: the "larva-first" and the "intercalation" hypotheses. Until recently, the larva-first hypothesis was preeminent. This proposes that the original indirect life cycle of bilaterians included a planktotrophic larva followed by a benthic adult. Phylogenetic evidence suggests that a planktotrophic larva is plesiomorphic for echinoderms. A preponderance of developmental studies on echinoderms may have foster...
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Page LR Tags: Biol Bull Source Type: journals

Egg Size as a Life History Character of Marine Invertebrates: Is It All It's Cracked Up to Be?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Egg size is one of the most important aspects of the life history of free-spawning marine organisms, and it is correlated with larval developmental mode and many other life-history characters. Egg size is simple to measure and data are available for a wide range of taxa, but we have a limited understanding of how large and small eggs differ in composition; size is not always the best measure of the characters under selection. Large eggs are generally considered to reflect increased maternal investment, but egg size alone can be a poor predictor of energetic content within and among taxa. We review techniques that have ...
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Moran AL, McAlister JS Tags: Biol Bull Source Type: journals

Larval Biology of the Crab Rhithropanopeus harrisii (Gould): A Synthesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This synthesis reviews the physiological ecology and behavior of larvae of the benthic crab Rhithropanopeus harrisii, which occurs in low-salinity areas of estuaries. Larvae are released rhythmically around the time of high tide in tidal estuaries and in the 2-h interval after sunset in nontidal estuaries. As in most subtidal crustaceans, the timing of larval release is controlled by the developing embryos, which release peptide pheromones that stimulate larval release behavior by the female to synchronize the time of egg hatching. Larvae pass through four zoeal stages and a postlarval or megalopal stage that are plank...
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Forward RB Tags: Biol Bull Source Type: journals

Quantifying the "bio-" components in biophysical models of larval transport in marine benthic invertebrates: advances and pitfalls.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Biophysical models are being used increasingly, both as predictive tools of larval dispersal for a particular system and for general evaluation of the role of different factors in larval transport. In the results of such models, larval duration, mortality, and behavior in the water column have exhibited pronounced effects on larval dispersal of marine benthic invertebrates. The parameterization of these processes has broadly reflected values from laboratory experiments, but the accuracy of these values is unknown. The pelagic larval duration used in models should be determined by laboratory, or preferably field, studie...
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Metaxas A, Saunders M Tags: Biol Bull Source Type: journals

Larval Development With Transitory Epidermis in Paranemertes peregrina and Other Hoplonemerteans.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report development with transitory epidermis in two other species, review evidence from the literature, and suggest that this developmental type is the rule for hoplonemerteans. The hoplonemertean planuliform larva is fundamentally different both from the pilidium larva of the sister group to the Hoplonemertea, the Pilidiophora, and from the hidden trochophore of palaeonemerteans. We discuss the possible function and homology of the larval epidermis in development of other nemerteans and spiralians in general. PMID: 19556594 [PubMed - in process] (Source: The Biological Bulletin)
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Maslakova SA, von Döhren J Tags: Biol Bull Source Type: journals

Shaping the things to come: ontogeny of lophotrochozoan neuromuscular systems and the tetraneuralia concept.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Despite the large variation in adult bodyplan phenotypes, a worm-shaped morphology is considered plesiomorphic for both Lophotrochozoa and Bilateria. Although almost all larval and adult lophotrochozoan worms have serially arranged ring muscles in their body wall, a comparison of their ontogeny reveals no less than six different developmental pathways that lead to this homogenous arrangement of ring muscles. However, in all taxa, with the exception of chaetodermomorph molluscs and the segmented annelids, ring muscle development starts with synchronous formation of certain pioneer myocytes, which is thus considered basa...
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Wanninger A Tags: Biol Bull Source Type: journals

Sniffing out new data and hypotheses on the form, function, and evolution of the echinopluteus post-oral vibratile lobe.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The performance requirements of ciliary band feeding explain the convoluted forms of many marine invertebrate larvae. Convolutions increase surface area and therefore feeding rates per unit body volume. We review recent advances in morphology, neural development, and behavior at settlement of the echinoid Lytechinus pictus and provide new ultrastructural and expression data on larvae of its congener, L. variegatus. Larvae of the echinometrid Colobocentrotus atratus contain neurons identified by their expression of nitric oxide synthase (NOS), indicating that this character is not unique to Lytechinus. We hypothesize th...
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Bishop CD, Hall BK Tags: Biol Bull Source Type: journals

Nervous system development in feeding and nonfeeding asteroid larvae and the early juvenile.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Larval and juvenile nervous systems (NS) of three asterinid sea stars with contrasting feeding and nonfeeding modes of development were characterized using the echinoderm-specific synaptotagmin antibody. In the feeding bipinnaria and brachiolaria larvae of Patiriella regularis, the species with ancestral-type development, an extensive NS was associated with the ciliary bands (CBs) and attachment complex. Lecithotrophic planktonic (Meridastra calcar) and benthic (Parvulastra exigua) brachiolariae lacked CBs and the associated NS, but had an extensive NS in the attachment complex. The similarity in the distribution and m...
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Elia L, Selvakumaraswamy P, Byrne M Tags: Biol Bull Source Type: journals

Feeding Ability of Early Zoeal Stages of the Norway Lobster Nephrops norvegicus (L.).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The wide geographical distribution of the Norway lobster, Nephrops norvegicus, results in a delay, with latitudinal decrease, in the larval season from spring to winter. Newly hatched larvae of the species may therefore be exposed to suboptimal levels or types of prey and face intermittent periods of starvation at low latitudes. This work investigated the feeding response of the first two zoeal stages of N. norvegicus under variable prey densities, prey types, feeding histories, and photoperiods. Both zoeae (Z) I and II increased the number of consumed prey with increasing food levels. ZI preferred Artemia sp. nauplii ...
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Pochelon PN, Calado R, Dos Santos A, Queiroga H Tags: Biol Bull Source Type: journals

Pre-settlement behavior in larval bryozoans: the roles of larval age and size.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Larval behaviors prior to settlement are important for both dispersal and the likelihood that larvae will encounter settlement habitat. The role of endogenous factors such as larval age and size are likely to be important in determining pre-settlement behavior but are less well understood than exogenous factors. In a simple experiment we explored the role of larval age and size on pre-settlement behavior in two species of bryozoan. We then used the results of this experiment to develop a theoretical model, which explored potential fitness benefits associated with phenotype-dependent changes in larval behavior (i.e., be...
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Burgess SC, Hart SP, Marshall DJ Tags: Biol Bull Source Type: journals

Not my "type": larval dispersal dimorphisms and bet-hedging in opisthobranch life histories.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
When conditions fluctuate unpredictably, selection may favor bet-hedging strategies that vary offspring characteristics to avoid reproductive wipe-outs in bad seasons. For many marine gastropods, the dispersal potential of offspring reflects both maternal effects (egg size, egg mass properties) and larval traits (development rate, habitat choice). I present data for eight sea slugs in the genus Elysia (Opisthobranchia: Sacoglossa), highlighting potentially adaptive variation in traits like offspring size, timing of metamorphosis, hatching behavior, and settlement response. Elysia zuleicae produced both planktotrophic a...
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Krug PJ Tags: Biol Bull Source Type: journals

Pelagic larval duration and dispersal distance revisited.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
I present dispersal distances for 44 species with data on propagule duration (PD) for 40 of these. Data were combined with those in Shanks et al. (2003; Ecol. Appl. 13: S159-S169), providing information on 67 species. PD and dispersal distance are correlated, but with many exceptions. The distribution of dispersal distances was bimodal. Many species with PDs longer than 1 day dispersed less than 1 km, while others dispersed tens to hundreds of kilometers. Organisms with short dispersal distances were pelagic briefly or remained close to the bottom while pelagic. Null models of passively dispersing propagules adequately...
Source: The Biological Bulletin - May 31, 2009 Category: Biology Authors: Shanks AL Tags: Biol Bull Source Type: journals

Evidence that the swim afferent neurons of tritonia diomedea are glutamatergic.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The escape swim response of the marine mollusc Tritonia diomedea is a well-established model system for studies of the neural basis of behavior. Although the swim neural network is reasonably well understood, little is known about the transmitters used by its constituent neurons. In the present study, we provide immunocytochemical and electrophysiological evidence that the S-cells, the afferent neurons that detect aversive skin stimuli and in turn trigger Tritonia's escape swim response, use glutamate as their transmitter. First, immunolabeling revealed that S-cell somata contain elevated levels of glutamate compared t...
Source: The Biological Bulletin - March 31, 2009 Category: Biology Authors: Megalou EV, Brandon CJ, Frost WN Tags: Biol Bull Source Type: journals

Glutamatergic transmission in hydra: NMDA/D-serine affects the electrical activity of the body and tentacles of Hydra vulgaris (Cnidaria, Hydrozoa).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, extracellular recordings were made from the tentacle and peduncle of hydra during bath application of NMDA and d-serine (both at 1 x 10(-5) mol l(-1) to 1 x 10(-9) mol l(-1)) in the presence of 1 x 10(-7) mol l(-1) AMPA or kainate. NMDA/d-serine produced a significant increase in tentacle activity, increasing the rate of tentacle pacemaker pulses (TPs) at 1 x 10(-7) mol l(-1), and small, behaviorally uncorrelated tentacle pulses (SUTPs) at 1 x 10(-5) mol l(-1). The NMDA antagonist, d-2-amino-5-phosphonopentanoic acid (D-AP5), counteracted the effects. NMDA/d-serine (1 x 10(-7) mol l(-1)) also caused a potent...
Source: The Biological Bulletin - March 31, 2009 Category: Biology Authors: Kay JC, Kass-Simon G Tags: Biol Bull Source Type: journals

The canonical network of autotrophic intermediary metabolism: minimal metabolome of a reductive chemoautotroph.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chemoautorophs that fix carbon by the reductive tricarboxylic acid cycle represent one of the dominant bacterial life forms that make a major contribution to biomass production. From the viewpoint of biogenesis, construction of a canonical chart of intermediary metabolism for this class of organisms may help us to understand early cellular evolution and point us to the last universal common ancestor. Data-mining the KEGG Pathways database enabled us to integrate required biosynthetic pathways and derive a chart that represents the complete anabolic network of a reductive chemoautotroph. Compounds of this metabolic netw...
Source: The Biological Bulletin - March 31, 2009 Category: Biology Authors: Srinivasan V, Morowitz HJ Tags: Biol Bull Source Type: journals

Transcriptome analysis of the circadian regulatory network in the coral Acropora millepora.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Entrained circadian rhythms control many biological processes. These cyclical systems are synchronized by environmental signals but continue to free run for a considerable time when the synchronizing stimuli are removed. In scleractinian corals that reproduce by broadcast spawning, timing processes are essential in ensuring successful fertilization. It is not known whether spawn timing is regulated directly by environmental signals or if it is entrained and regulated by circadian or circalunar rhythms. The genetic components of circadian systems have been studied in considerable detail in microbes, plants, and animals....
Source: The Biological Bulletin - March 31, 2009 Category: Biology Authors: Vize PD Tags: Biol Bull Source Type: journals

Cyclic guanosine monophosphate signaling cascade mediates pigment aggregation in freshwater shrimp chromatophores.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The cell signaling cascades that mediate pigment movements in crustacean chromatophores are not yet well established, although Ca(2+) and cyclic nucleotide second messengers are involved. Here, we examine the participation of cyclic guanosine monophosphate (cGMP) in pigment aggregation triggered by red pigment concentrating hormone (RPCH) in the red ovarian chromatophores of freshwater shrimp. In Ca(2+)-containing (5.5 mmol l(-1)) saline, 10 micromol l(-1) dibutyryl cGMP alone produced complete pigment aggregation with the same time course ( approximately 20 min) and peak velocity ( approximately 17 microm/min) as 10(-...
Source: The Biological Bulletin - March 31, 2009 Category: Biology Authors: Ribeiro MR, McNamara JC Tags: Biol Bull Source Type: journals

Spawning, development, and the duration of larval life in a deep-sea cold-seep mussel.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We describe culturing techniques and development for the cold-seep mussel "Bathymodiolus" childressi, the only deep-sea bivalve for which development has been detailed. Spawning was induced in mature mussels by injection of 2 mmol l(-1) serotonin into the anterior adductor muscle. The mean egg diameter is 69.15 +/- 2.36 microm (+/-S.D.; n = 50) and eggs are negatively buoyant. Cleavages are spiral and at 7-8 degrees C occur at a rate of one per 3-9 h through hatching, with free-swimming blastulae hatching by 40 h and shells beginning to develop by day 12. When temperature was raised to 12-14 degrees C after hatching, larva...
Source: The Biological Bulletin - March 31, 2009 Category: Biology Authors: Arellano SM, Young CM Tags: Biol Bull Source Type: journals

The bilaterally asymmetrical larval form of Stomopneustes variolaris (Lamarck).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study describes the echinopluteus and juveniles of the Indo-Pacific echinoid Stomopneustes variolaris. Late 4-armed larvae had left postoral arms that were longer and more deeply red pigmented than the right arms. Two weeks into development, the sixth pair of arms, the posterolaterals, began to form as these larvae achieved an arbacioid form. The right posterolateral arm grew long, was heavily pigmented at the tip, and was oriented perpendicularly or obliquely to the main body axis. The left posterolateral arm was relatively short, with little pigment. Two of several hundred larvae examined showed different patterns. ...
Source: The Biological Bulletin - March 31, 2009 Category: Biology Authors: Emlet RB Tags: Biol Bull Source Type: journals

Impacts of suspended sediments on fertilization, embryonic development, and early larval life stages of the pacific herring, Clupea pallasi.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Pacific herring reproduce in the San Francisco Bay estuary during times of the year when suspended sediment loads are highest due to freshwater input, yet little is known about the effects of sediment on herring early life stages. During the first 2 h after eggs contacted water, embryos were adhesive and susceptible to having sediment particles attach permanently to the chorion. Treatment with suspended San Francisco Bay dredged sediments at ecologically relevant concentrations of 250 or 500 mg/l during this time period increased self-aggregation of the eggs and led to sublethal and lethal effects. After the first 2 h ...
Source: The Biological Bulletin - March 31, 2009 Category: Biology Authors: Griffin FJ, Smith EH, Vines CA, Cherr GN Tags: Biol Bull Source Type: journals

Evidence for costs of mating and self-fertilization in a simultaneous hermaphrodite with hypodermic insemination, the Opisthobranch Alderia willowi.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Simultaneous hermaphrodites offer the chance to study antagonistic coevolution between the sexes when individuals function in both roles. Traumatic mating by hypodermic insemination has repeatedly evolved in hermaphroditic taxa, but evidence for the fitness costs of such male-advantage traits is lacking. When reared in isolation, specimens of the sea slug Alderia willowi (Opisthobranchia: Sacoglossa) initially laid clutches of unfertilized eggs but 4 days later began self-fertilizing; this is only the third report of selfing in an opisthobranch. Hypodermic insemination may allow selfing in Alderia if penetration of the...
Source: The Biological Bulletin - March 31, 2009 Category: Biology Authors: Smolensky N, Romero MR, Krug PJ Tags: Biol Bull Source Type: journals

Oral Administration of Pharmacologically Active Substances to Squid: A Methodological Description.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. The squid giant synapse is a well-defined experimental preparation for the study of ligand-dependant synaptic transmission. Its large size gives direct experimental access to both presynaptic and postsynaptic junctional elements, allowing direct optical, biophysical, and electrophysiological analysis of depolarization-release coupling. However, this important model has not been utilized in pharmacological studies, other than those implementable acutely in the in vitro condition. A method is presented for oral administration of bioactive substances to living squid. Electrophysiological characterization and dir...
Source: The Biological Bulletin - February 1, 2009 Category: Biology Authors: Berk W, Teperman J, Walton KD, Hirata K, Sugimori M, Llinas RR Tags: Biol Bull Source Type: journals

Behaving in the Dark: Locomotor, Chromatic, Postural, and Bioluminescent Behaviors of the Deep-Sea Squid Octopoteuthis deletron Young 1972.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Visual behaviors are prominent components of intra- and interspecific communication in shallow-water cephalopods. Meso- and bathypelagic cephalopods were believed to have limited visual communication, other than bioluminescence, due to the reduced illumination at depth. To explore potential visual behaviors in mesopelagic squid, we used undersea vehicles to observe 76 individuals of Octopoteuthis deletron. In contrast to predictions, we found this species capable of a variety of visually linked behaviors not previously reported for a deep-ocean cephalopod. The resultant ethogram describes numerous chromatic, postural, ...
Source: The Biological Bulletin - February 1, 2009 Category: Biology Authors: Bush SL, Robison BH, Caldwell RL Tags: Biol Bull Source Type: journals

Mass Culture and Characterization of Tumor Cells From a Naturally Occurring Invertebrate Cancer Model: Applications for Human and Animal Disease and Environmental Health.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
On the northeastern coast of the United States and Canada, Mya arenaria, the soft shell clam, develops a diffuse, hemopoetic tumor (a fatal leukemia-like cancer) resulting from inactivation of p53-like family member proteins.These malignant cells provide a model for an unrelated set of human cancer cells that are also characterized by mortalin-based cytoplasmic sequestration of wild-type p53 tumor suppressor protein (mortalin is the mitochondrial Hsp70 protein). Here we describe methods for mass culture and long-term storage of tumor cells from this cancer. These are the first successful efforts at maintaining malignan...
Source: The Biological Bulletin - February 1, 2009 Category: Biology Authors: Walker C, Böttger SA, Mulkern J, Jerszyk E, Litvaitis M, Lesser M Tags: Biol Bull Source Type: journals

Calyculin-A Induces Cleavage in a Random Plane in Unfertilized Sea Urchin Eggs.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Calyculin-A (CLA), a protein phosphatase inhibitor, has been known to induce cleavage resembling normal furrowing in unfertilized sea urchin eggs. In CLA-treated eggs, actin filaments and myosin assemble to form a contractile ring-like structure in the egg cortex; however, this occurs in the absence of a mitotic spindle or asters. Here, we investigated the relationship between the plane of CLA-induced cleavage and the intrinsic animal-vegetal polar axis in sea urchin eggs. The animal-vegetal axis was established using black ink to visualize the jelly canal located at the animal pole in the jelly coat surrounding the eg...
Source: The Biological Bulletin - February 1, 2009 Category: Biology Authors: Goda M, Inoué S, Mabuchi I Tags: Biol Bull Source Type: journals

Low Oxygen Consumption and High Body Content of Catch Connective Tissue Contribute to Low Metabolic Rate of Sea Cucumbers.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. The energy consumption of echinoderms is low in comparison with that of other invertebrates. We demonstrated this by measuring the oxygen consumption rate per unit of body weight (VO(2)) of the sea cucumber Actinopyga mauritiana: VO(2) was 1/8 that of the "standard" invertebrates. Low energy consumption in echinoderms has been attributed to their high skeletal content and to catch connective tissues (CCTs) that maintain body posture by altering their mechanical properties with little energy expenditure. The former is not applicable to holothurians, and the latter has not been proven experimentally. We postula...
Source: The Biological Bulletin - February 1, 2009 Category: Biology Authors: Takemae N, Nakaya F, Motokawa T Tags: Biol Bull Source Type: journals

Temporal Variability in Chlorophyll Fluorescence of Back-Reef Corals in Ofu, American Samoa.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Change in the yield of chlorophyll a fluorescence is a common indicator of thermal stress in corals. The present study reports temporal variability in quantum yield measurements for 10 coral species in Ofu, American Samoa-a place known to experience elevated and variable seawater temperatures. In winter, the zooxanthellae generally had higher dark-adapted maximum quantum yield (F(v)/F(m)), higher light-adapted effective quantum yield (DeltaF/F'(m)), and lower relative electron transport rates (rETR) than in the summer. Temporal changes appeared unrelated to the expected bleaching sensitivity of corals. All sp...
Source: The Biological Bulletin - February 1, 2009 Category: Biology Authors: Piniak GA, Brown EK Tags: Biol Bull Source Type: journals

Red Fluorescent Protein Responsible for Pigmentation in Trematode-Infected Porites compressa Tissues.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract. Reports of coral disease have increased dramatically over the last decade; however, the biological mechanisms that corals utilize to limit infection and resist disease remain poorly understood. Compromised coral tissues often display non-normal pigmentation that potentially represents an inflammation-like response, although these pigments remain uncharacterized. Using spectral emission analysis and cryo-histological and electrophoretic techniques, we investigated the pink pigmentation associated with trematodiasis, infection with Podocotyloides stenometre larval trematode, in Porites compressa. Spectral emiss...
Source: The Biological Bulletin - February 1, 2009 Category: Biology Authors: Palmer CV, Roth MS, Gates RD Tags: Biol Bull Source Type: journals

Seawater Temperature Alters Feeding Discrimination by Cold-Temperate but not Subtropical Individuals of an Ectothermic Herbivore.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study represents the first demonstration that short-term (i.e., days-long) variation in ambient temperature alters feeding choices in a marine herbivore. PMID: 19218494 [PubMed - as supplied by publisher] (Source: The Biological Bulletin)
Source: The Biological Bulletin - February 1, 2009 Category: Biology Authors: Sotka EE, Giddens H Tags: Biol Bull Source Type: journals