bluuebunny/crossref_metadata_2025 huggingface dataset:
CONTRAST ENHANCEMENT OF EXTRADURAL COMPRESSIVE MATERIAL ON MAGNETIC RESONANCE IMAGING
Authors: SURAN JANTRA NGOSUWAN , DURHAM AMY , MAI WILFRIED , SEILER GABRIELA S
Published: August 2010

Gadolinium‐enhancement of compressive extradural material is detected occasionally with magnetic resonance (MR) imaging in dogs. Our goal was to characterize contrast enhancement of extradural compressive material associated with intervertebral disc herniation, and to evaluate the association between enhancement and histopathologic findings and the onset of clinical signs. Ninety‐three dogs with a total of 99 lesions diagnosed as intervertebral disc herniation on MR imaging were assessed. Images were evaluated for lesion location, type of herniation, degree of compression, intramedullary T2‐weighted (T2W) intensities, and contrast enhancement. In 23 dogs, surgically removed compressive material was evaluated histopathologically for hemorrhage, inflammation, neovascularization, fibroplasia, fibrosis, mineralization, necrosis, and chronicity. Contrast enhancement of extradural compressive material, meninges, and both the compressive materials and meninges was present in 51.5%, 39.4%, and 17.2% of lesions, respectively. Extradural enhancement occurred more frequently in extrusions than protrusions (P=0.001). Meningeal enhancement and more severe neurologic deficits were significantly associated with a shorter duration of clinical signs (P=0.04 and 0.01, respectively). Intramedullary T2W hyperintensities, present with 44.4% of lesions, were associated with more severe neurologic deficits (P=0.001). Lesions with extradural enhancement were more often considered subacute to chronic in duration and more frequently associated with hemorrhage compared with nonenhancing material; however, no statistically significant association was established between contrast enhancement and histopathologic findings. Contrast enhancement of extradural compressive material and the meninges was found to be common with intervertebral disc herniation, and should not be interpreted as a specific sign of a mass lesion such as neoplasia.
THE EFFECT OF THE SAMPLE SIZE AND LOCATION ON CONTRAST ULTRASOUND MEASUREMENT OF PERFUSION PARAMETERS
Authors: LEINONEN MERJA R. , RAEKALLIO MARJA R. , VAINIO OUTI M. , RUOHONIEMI MIRJA O. , O'BRIEN ROBERT T.
Published: August 2010

Contrast‐enhanced ultrasound can be used to quantify tissue perfusion based on region of interest (ROI) analysis. The effect of the location and size of the ROI on the obtained perfusion parameters has been described in phantom, ex vivo and in vivo studies. We assessed the effects of location and size of the ROI on perfusion parameters in the renal cortex of 10 healthy, anesthetized cats using Definity® contrast‐enhanced ultrasound to estimate the importance of the ROI on quantification of tissue perfusion with contrast‐enhanced ultrasound. Three separate sets of ROIs were placed in the renal cortex, varying in location, size or depth. There was a significant inverse association between increased depth or increased size of the ROI and peak intensity (P<0.05). There was no statistically significant difference in the peak intensity between the ROIs placed in a row in the near field cortex. There was no significant difference in the ROIs with regard to arrival time, time to peak intensity and wash‐in rate. When comparing two different ROIs in a patient with focal lesions, such as suspected neoplasia or infarction, the ROIs should always be placed at same depth and be as similar in size as possible.
Diet with a low n‐6/n‐3 essential fatty acid ratio when started immediately after the onset of overt diabetes prolongs survival of type 1 diabetes model NOD mice
Authors: Kagohashi Yukiko , Otani Hiroki
Published: August 2010

Type 1 diabetes is a multifactorial disease involving genetic and environmental factors and results from the destruction of pancreatic islet β cells, virtually the only source of insulin. When the majority of β cells are lost, a ‘honeymoon’ period of variable length follows: namely, a fleeting phase of residual endogenous insulin production, during which glycemic control is achieved with modest or no doses of insulin. However, the remaining β cells are eventually lost, causing the individual to become insulin‐dependent and to require long‐term insulin therapy or islet transplantation. Here we show that NOD mice, a type 1 diabetes model, survived significantly longer when their diet was changed from one chow with a high essential fatty acid (EFA) ratio (n‐6/n‐3, 14.5) to another with a low n‐6/n‐3 ratio (3.0) within 6 days after the onset of overt diabetes (i.e. the ‘honeymoon’ period), than mice that were continuously fed with the chow with the high n‐6/n‐3 ratio. This effect was not observed when the chow was changed later than 9 days after the onset. Significantly larger number of islets remained with suggestive islet neogenesis from the pancreatic duct and pathological changes in renal glomeruli were significantly milder in NOD mice fed the chow with the low n‐6/n‐3 ratio within 6 days after the onset of overt diabetes than those continuously fed with the high‐n‐6/n‐3‐ratio chow. These findings indicate that a diet with a low n‐6/n‐3 ratio prolongs the ‘honeymoon’ period by retaining the β cell mass, suggesting its potential therapeutic merit.
Relationship between Serum Acetaminophen Concentration and N‐Acetylcysteine‐Induced Adverse Drug Reactions
Authors: Zyoud Sa’ed H. , Awang Rahmat , Sulaiman Syed Azhar Syed , Khan Halilol Rahman Mohamed , Sawalha Ansam F. , Sweileh Waleed M. , Al‐Jabi Samah W.
Published: August 2010

Abstract:  Intravenous N‐acetylcysteine is usually regarded as a safe antidote. However, during the infusion of the loading dose, different types of adverse drug reactions (ADR) may occur. The objective of this study was to investigate the relation between the incidence of different types of ADR and serum acetaminophen concentration in patients presenting to the hospital with acetaminophen overdose. This is a retrospective study of patients admitted to the hospital for acute acetaminophen overdose over a period of 5 years (1 January 2004 to 31 December 2008). Parametric and non‐parametric tests were used to test differences between groups depending on the normality of the data. SPSS 15 was used for data analysis. Of 305 patients with acetaminophen overdose, 146 (47.9%) were treated with intravenous N‐acetylcysteine and 139 (45.6%) were included in this study. Different types of ADR were observed in 94 (67.6%) patients. Low serum acetaminophen concentrations were significantly associated with cutaneous anaphylactoid reactions but not other types of ADR. Low serum acetaminophen concentration was significantly associated with flushing (p < 0.001), rash (p < 0.001) and pruritus (p < 0.001). However, there were no significant differences in serum acetaminophen concentrations between patients with and without the following ADR: gastrointestinal reactions (p = 0.77), respiratory reactions (p = 0.96), central nervous reactions (p = 0.82) and cardiovascular reactions (p = 0.37). In conclusion, low serum acetaminophen concentrations were associated with higher cutaneous anaphylactoid reactions. Such high serum acetaminophen concentrations may be protective against N‐acetylcysteine‐induced cutaneous ADR.
In vitroReactivating Effects of Standard and Newly Developed Oximes on Malaoxon‐Inhibited Mouse Brain Acetylcholinesterase
Authors: Dos Santos Alessandra Antunes , Dos Santos Danúbia Bonfanti , Dafre Alcir Luiz , De Bem Andreza Fabro , Souza Diogo Onofre , Da Rocha João Batista Teixeira , Kuca Kamil , Farina Marcelo
Published: August 2010

Abstract: Malathion is an organophosphate (OP) pesticide whose toxicity depends on its bioactivation to malaoxon. Human malathion poisoning has been treated with oximes (mainly pralidoxime) in an attempt to reactivate OP‐inhibited acetylcholinesterase (AChE). However, pralidoxime has shown unsatisfactory therapeutic effects in malathion poisoning and its routine use has been questioned. In this study, we evaluated thein vitropotency of standards and newly developed oximes in reactivating malaoxon‐inhibited AChE derived from mouse brain supernatants. Malaoxon displayed a concentration‐dependent inhibitory effect on mouse brain AChE (IC50 = 2.36 μM), and pralidoxime caused a modest reactivating effect (30% of reactivation at 600 μM). Obidoxime and trimedoxime, as well as K047 and K075, displayed higher reactivating effects (from 55% to 70% of reactivation at 600 μM) when compared with pralidoxime. The results show that obidoxime, trimedoxime, K074 and K075 present higher reactivating effects on malaoxon‐inhibited AChE underin vitroconditions when compared with pralidoxime. Taking into account the unsatisfactory effects of pralidoxime as antidotal treatment in malathion poisonings, the present results suggest that obidoxime, trimedoxime, K074 and K075 might be interesting therapeutic strategies to reactivate malaoxon‐inhibited AChE in malathion poisonings.
Effects of eutrophication on bioeroding sponge communities with the description of new West Indian sponges, Cliona spp. (Porifera: Hadromerida: Clionidae)
Authors: Holmes Katherine E.
Published: August 2010

Abstract. Pieces of coral rubble (Porites porites), collected from across 3 fringing reefs that lie along a eutrophication gradient, were examined for the presence of clionid sponges. A similarity analysis of species composition showed that reef zone had less effect on clionid community composition than did other factors affecting the reefs as a whole. Except on the back reef, the Zones, distances, and depths within the reefs had no significant influence on the number of clionid invasions. Reef comparisons demonstrated that clionid abundance increased with increasing eutrophication. Clionids were found in 41% of the pieces collected from the most eutrophic site vs. 24% from the least eutrophic. Because clionids are the principal bio‐eroders of coral reefs, any increase in their abundance will likely result in greater bioerosion rates. The mean abundance of Type 3 corals (in which fragmentation is the primary mode of propagation) is positively related to the frequency of boring sponge invasion. suggesting that increased bioerosion may be partly responsible for community shifts toward Type 3 corals in polluted waters. Cliona cf. vastifica, found for the first time in Barbados, flourishes on the most eutrophic reef and may become an important bioeroder under the highly eutrophic conditions that have begun to plague West Indian reefs. Two new species of Cliona (Porifera: Hadro‐merida: Clionidae) are described.
Torsion in Patella caerulea (Mollusca, Patellogastropoda): ontogenetic process, timing, and mechanisms
Authors: Wanninger Andreas , Ruthensteiner Bernhard , Haszprunar Gerhard
Published: August 2010

Abstract. Torsion is a process in gastropod ontogenesis where the visceral body portion rotates 180° relative to the head/foot region. We investigated this process in the limpet Patella caerulea by using light microscopy of living larvae, as well as scanning electron microscopy (SEM) of larvae fixed during the torsion process. The completion of the 180° twist takes considerably less time in larvae of Patella caerulea than previously described for other basal gastropod species. At a rearing temperature of 20–22°C, individuals complete ontogenetic torsion in −2 h. Furthermore, the whole process is monophasic, i.e., carried out at a constant speed, without any evidence of distinct ‘fast” or ‘slow” phases. Both larval shell muscles—the main and the accessory larval retractor—are already fully contractile before the onset of torsion. During the torsion process both retractors perform cramp‐like contractions at ∼30 s intervals, which are followed by hydraulic movements of the foot. However, retraction into the embryonic shell occurs only after torsion is completed. The formation of the larval operculum is entirely in‐dependent from ontogenetic torsion and starts before the onset of rotation, as does the mineralization of the embryonic shell. The reported variability regarding the timing (mono‐ versus biphasic; duration) of torsion in basal gastropod species precludes any attempt to interpret these data phylogenetically.

The present findings indicate that the torsion process in Patella caerulea, and probably generally in basal gastropods, is primarily caused by contraction of the larval shell muscles in combination with hydraulic activities. In contrast, the adult shell musculature, which is independently formed after torsion is completed, does not contribute to ontogenetic torsion in any way. Thus, fossil data relying on muscle scars of adult shell muscles alone appear inappropriate to prove torted or untorted conditions in early Paleozoic univalved molluses. Therefore, we argue that paleontological studies dealing with gastropod phylogeny require data other than those based on fossilized attachment sites of adult shell muscles.
Paraspermatogenesis in Littoraria (Palustorina) articulata, with reference to other Littorinidae (Littorinoidea, Caenogastropoda)
Authors: Buckland‐Nicks John A. , Healy John M. , Jamieson Barrie G.M. , O'Leary Stephen
Published: August 2010

Abstract. The ultrastructure of paraspermatogenesis is examined in the littorinid subfamily Littorininae, with special emphasis on Littoraria (Palustorina) articulata (PHILIPPI 1846). In particular the study focuses on the fate of the nucleus and origin of the rod bodies during parasperm development. Parasperm of the Littorininae are rounded or oblong cells, which undergo an abortive meiosis and eliminate part of the nucleus but often retain a nuclear remnant. The cytoplasm is filled with numerous spherical vesicles in all Littorininae, but in Littoraria (and in certain species of Nodilittorina, Tectarius and Cenchritis) dense ‘rod‐bodies’ also occur. Littoraria (Palustorina) are unique in possessing a flagellum‐like structure termed the ‘pseudotrich”, which lacks an axoneme but contains microtubules during its development. Paraspermatogonia differ from euspermatogonia in the structure of the nucleus and in the extensive rough endoplasmic reticulum (RER) and swollen cytoplasm. Two types of secretions develop in Littoraria: (1) numerous, spherical granules (composed of putative glycoprotein, also seen in other Littorininae) and (2) rhomboid granules (composition uncertain but reacting positively to RNA stains; these granules arising within RER cisternae close to the nucleus). As the rhomboid granules fuse to form the larger, rod‐bodies (polygonal in cross section), the RER membrane enclosing the rod‐bodies becomes confluent with the outer nuclear membrane, thereby forming a common compartment. Results of this study clearly show that the rod‐bodies are secretions of the RER cisternae and not, as claimed in some light microscopic accounts, the product of fusion of eusperm nuclei which have entered the parasperm cytoplasm (either by active eusperm penetration or by phagocytosis). Developmental characteristics of littorinid parasperm show differences between species and may, in some cases, provide characters diagnostic of subgenera.
Cuticular sensory receptors on the antenna and maxillary palp of a fly larva, Nephrotoma suturalis (Diptera: Tipulidae)
Authors: Baker Gerald T. , Davis Jennifer , Monroe William , Chandrapatya Angsumarn
Published: August 2010

Abstract. The apex of the larval antenna of the crane fly Nephrotoma suturalis has 6 cuticular sensilla that stained intensely black with silver nitrate, which indicates their porosity. The large sensory cone is innervated by 14 neurons and the 3 small, smooth surfaced, conical pegs have 4 neurons each. The small and large cylindrical sensilla with their smooth walls and pleated apices are innervated by 4 and 6 nerve cells, respectively. The 15 sensilla on the apex of the maxillary palp are all stained by silver nitrate. These sensilla are of five types: 7 type A sensilla with a smooth surface, a distinct apical pore, and 3 or 4 neurons; 2 type B sensilla with a smooth surface, many pores, and 5 neurons; 1 type C sensillum with a grooved surface, a large apical pore, smaller pores in the grooves, and 6 neurons; 3 type D sensilla with a smooth surface, a grooved apex that is elongated into a projection, and 4 neurons; 2 type E sensilla with many pores covering the surface, leaf‐like appearance, and 4 neurons. The number and types of sensilla are similar to those in other nematocerous larvae, but in the many different forms of sensilla and the structure of the sensory cone, these tipulid larvae differ greatly from other larvae of lower Diptera.
Natural growth lines in echinoid ossicles are not reliable indicators of age: a test using Strongylocentrotus droebachiensis
Authors: Russell Michael P. , Meredith Robert W.
Published: August 2010

Abstract. Natural growth lines in the ossicles of echinoids have been used to estimate age, calculate growth curves, and infer population age‐structure. However, few studies evaluate whether these bands are added annually–a critical assumption of the aging technique. We tested whether the banding pattern is annual in Strongylocentrotus droebachiensis. Sea urchins were tagged with a fluorescent marker, released into tidepools, and collected 1 year later. We quantified the position of the fluorescent mark relative to subsequent growth bands. In 30 individuals ranging in test diameter from 14 to 77 mm, and in a series of ∼2 mm size intervals, we examined 3 interambulacral plates (aboral, ambital, and oral) and a rotula from Aristotle's lantern. Overall, only 7 sea urchins (23%) added a complete band to all 4 ossicles. In 6 sea urchins (20%) at least 1 ossicle added more than 1 complete band. In many sea urchins, especially those >55 mm in diameter, most ossicles added less than 1 band. The banding pattern in ossicles seriously underestimates age in S. droebachiensis and population parameters inferred from these growth lines are biased. Before using the growth‐band aging method in other echinoids, it must be demonstrated that 1 band is added annually for all sizes in a population under field conditions.
Influence of delayed metamorphosis on postsettlement survival and growth in the sipunculan Apionsoma misakianum
Authors: Pechenik Jan A. , Rice Mary E.
Published: August 2010

Abstract. Certain stresses experienced by marine larvae from many groups can dramatically reduce aspects of juvenile performance. This study reports the effects of delayed metamorphosis and nutritional stress on survival and growth of the deposit‐feeding sipunculan Apionsoma (=Golfingia) misakianum. Approximately 600 larvae collected from the Florida Current plankton were distributed among 3 treatment groups. Ninety larvae (controls) were offered sediment and adult‐conditioned seawater 4 d after collection, to induce metamorphosis; larvae of this species could not be induced to metamorphose by increasing the K+ concentration of seawater. The remaining 500 larvae were kept swimming for either 2 or 4 weeks, with or without phyto‐plankton (clone T‐ISO). At the end of the periods of prolonged larval swimming, subsampled larvae (360) were induced to metamorphose as in the controls. Surviving individuals were retrieved 6 weeks after the addition of excess sediment in all treatments, and weighed to document growth. Neither delayed metamorphosis nor starvation influenced juvenile survival. However, starving larvae for 2 weeks significantly reduced mean juvenile growth rates relative to the mean growth rate of control individuals (p<0.0001), while prolonging larval life by 4 weeks significantly reduced mean juvenile growth rates (p<0.05) whether or not larvae were fed. Reduced juvenile growth rates may have been caused by nutritional stress experienced by larvae in both the starved and fed treatments. The rapid response of freshly collected larvae to sediment indicates that competent larvae of this species routinely delay metamorphosis in the field. The extent to which they also experience food limitation is not yet clear. If competent larvae are food limited while delaying metamorphosis in the field, our results suggest that juveniles will grow more slowly and may thus exhibit reduced fitness.
Ciliary ultrastructure of protobranchs (Mollusca, Bivalvia)
Authors: Lundin Kennet , Schander Christoffer
Published: August 2010

Abstract. The external epithelial cilia and other surface structures of the nuculoid protobranchs Nuculana pernula and Nucula nitidosa were studied. The gill lamellae and labial palps are partly covered with very long cilia. These have a modified slender distal portion, an ordinary metazoan‐type basal body, a basal foot. and a single, long cross‐striated rootlet. In cilia on the gills of N. nitidosa, the basal foot is thick and attaches to the next basal body directly behind. Unciliated surface areas on the gills, labial palps, and foot are covered with a dense brushborder of microvilli. We observed no specific homologies between the cilia of the protobranchs studied and the epidermal cilia of the enigmatic Xenoturbella bocki, hence the recent hypothesis of a close connection of the latter to the protobranch bivalves is questioned.
Reduction and variability of trunk spines in the acanthocephalan Corynosoma cetaceum: the role of physical constraints on attachment
Authors: Aznar F. Javier , Bush Albert O. , Raga Juan A.
Published: August 2010

Abstract. In this study, we investigated a functional trade‐off between trunk attachment and trunk‐spine development in the acanthocephalan Corynosoma cetaceum. The worms live attached to the stomach and upper intestine of their cetacean definitive hosts, using the proboscis and spiny foretrunk as the main holdfast; the spiny hindtrunk can also attach by bending ventrally. When the hindtrunk bends, ventral compression generates an anterior fold (AF) and a posterior fold (PF). A morphological analysis based on 7,823 individuals collected from 10 franciscana dolphins, Pontoporia blainvillei, revealed that spines were smaller and more variable in size and occurrence in the folds than on neighboring areas; the growth of fold spines seemed to be inhibited to various degrees. Spines were more reduced in the AF than in the PF, and spines of both folds were more reduced in females than in males. Patterns of reduction appeared to be directly related to the intensity of fold compression associated with hindtrunk bending. Fold compression could induce plastic inhibition of spine growth, and/or could make fold spines maladaptive, spines being reduced by natural selection. Apparently, fold spines neither contact the substrate, nor are they exposed to the environment when the hindtrunk attaches. Therefore, fold spines could have reduced, or lost, their primary function, at least in the definitive host. The reduction and variability of spines in C. cetaceum seem to be unique among Corynosoma species.
An aplacophoran postlarva with iterated dorsal groups of spicules and skeletal similarities to Paleozoic fossils
Authors: Scheltema Amélie H. , Ivanov Dmitry L.
Published: August 2010

Abstract. A tiny neomenioid postlarva (Neomeniomorpha, or Solenogastres) collected from the water column 3 to 6 m above the east Pacific seamount Fieberling Guyot has 6 iterated, transverse groups of spicules and 7 regions devoid of spicules between the transverse groups and the anterior‐and posteriormost spicules. Three pairs of ventral, longitudinal zones with columns of single spicules, each pair with its own distinctive spicule morphology, lack transverse iteration. The 7 regions bare of spicules are compared to shell fields in developing polyplacophorans, and spicule arrangement is compared to sclerite arrangement on the Cambrian fossils Wiwaxia corrugata and Halkieria evangelista and to the spines and shell plates of the Silurian Acaenoplax hayae. The term iteration is used to denote processes that result in both metameric segments and repeated ectodermal skeletal structures. Iterative morphogenesis was probably present in bilateral animals before the Cambrian. Comparisons of iterated ectodermal skeletal structures among fossil and extant forms are suggested to indicate evolutionary relationship.
Survival of heterotopic heart xenografts from Helisoma duryi, Planorbula armigera, and Planorbarius corneus in Biomphalaria glabrata (Pulmonata, Basommatophora, Planorbidae): evidence for phylogenetic relatedness?
Authors: Sullivan John T. , Farengo Dana A.
Published: August 2010

Abstract. Heart xenografts from the pulmonate snail Helisoma trivolvis survive in Biomphalaria glabrata, whereas xenografts from most other pulmonate snail genera are rejected within 3 to 15 days. To test whether xenografts from snails closely related to H. trivolvis were also accepted, specimens of an albino strain of B. glabrata were implanted with hearts from H. duryi, Planorbula armigera, and Planorbarius corneus. The fate of implants was monitored for 180 days by measuring heartbeat and by histological analysis. All 3 types of implants survived beyond the 3 to 15 days required for the complete destruction of incompatible xenografts, suggesting a degree of physiological and immunological compatibility between B. glabrata and these donors. Among the 3 types of xenografts, all from H. duryi survived for the entire 180 days. Fewer grafts from P. armigera and P. corneus survived for prolonged periods, although some still were beating at 60 and 180 days post implantation (DPI) respectively, suggesting that a range of histocompatibility, and perhaps phylogenetic relatedness, with B. glabrata occurs within this group. Paradoxically, the initial hemocytic response by the recipient was strongest against grafts from H. duryi, the most compatible donor, while responses to grafts from P. armigera and P. corneus were mild or did not occur during the first 7 DPI. We used 2 albino strains of B. glabrata in these studies, and the data suggest slight differences in recipient strain compatibility.
Methane‐based symbiosis in a mussel, Bathymodiolus platifrons, from cold seeps in Sagami Bay, Japan
Authors: Barry James P. , Buck Kurt R. , Kochevar Randall K. , Nelson Douglas C. , Fujiwara Yoshihiro , Goffredi Shana K. , Hashimoto Jun
Published: August 2010

Abstract. Bathymodiolus platifrons, a chemosynthetic mussel from cold seeps off Japan, relies for its nutrition on the productivity of methylotrophic or methanotrophic endosymbionts. High densities of bacterial symbionts appearing to be type I methanotrophs were observed in transmission electron micrographs of gill tissues. Methanol dehydrogenase activity in gill tissue from a single individual was positive compared to non‐methanotrophic control samples, indicating a high potential for methanotrophy. Stable isotopic ratios of carbon in symbiont‐containing gill tissue, as well as host tissues, were extremely depleted in 13C, and similar to values reported for other methanotrophic species. TEMs of gill tissue showing symbionts in various stages of digestion support the hypothesis that carbon transfer from symbionts to B. platifrons occurs through intracellular digestion of the symbionts. Discovery of methane‐ or methanolbased symbioses in B. platifrons from cold seeps in Sagami Bay extends the range of such symbioses to include cold seeps and hydrothermal vents, and supports the idea that environmental methane levels control the distribution of these symbioses.
Intracerebral ocelli in an amphipod: extraretinal photoreceptors of the sandhopper Talitrus saltator (Crustacea, Amphipoda)
Authors: Frelon‐Raimond Maryline , Meyer‐Rochow V. Benno , Ugolini Alberto , Martin Gilbert
Published: August 2010

Abstract. No morphological clues on the amphipod head indicate the existence of ocelli. However, as in several isopod species studied so far, two rudimentary photoreceptors are integrated into the medio‐dorsal part of the brain. This electron microscopical study of the photoreceptors is the first report on the presence of ocelli in amphipods. Each ocellus is made up of 3 receptor cells which contribute to the formation of a photoreceptive surface (the rhabdom) formed by tightly packed microvilli. The rhabdoms are twisted and irregular in outline. Membrane turnover is suggested by the presence of different kinds of lysosomes. Lacking dioptric lenses, these photoreceptors are not likely to be involved in image formation but may function as appraisers of ambient light intensity. Physiological and behavioral studies will, henceforth, have to take into account these unexpected ocelli, which may represent remnants of the naupliar eye.
Systematic relationships of Nematomorpha based on molecular and morphological data
Authors: Bleidorn Christoph , Schmidt‐Rhaesa Andreas , Garey James R.
Published: August 2010

Abstract. We sequenced the 18S rRNA gene from 11 nematomorph species from 9 genera and derived hypotheses concerning the sister group of Nematomorpha and relationships within this taxon. The molecular and morphological data are consistent with the monophyly of Nematomorpha, a sister‐group relationship between Nematomorpha and Nematoda, and a sister‐group relationship between the marine genus Nectonema and all of the freshwater taxa, Gordiida. Hypotheses of relationships within Gordiida support the traditional taxa Gordiidae, Chordodidae, and Chordodinae but reject Parachordodinae and Spinochordodidae. The molecular results differ from those of previous morphological studies by suggesting a reduction of the two tail lobes at the posterior end of males in Chordodinae, monophyly of the genus Paragordionus, and paraphyly of the genus Chordodes.
Caudal regeneration in Tubifex tubifex (Oligochaeta, Tubificidae) following copper exposure
Authors: Bouché Marie‐Laure , Arnoult Fabrice , Vernet Guy
Published: August 2010

Abstract. The oligochaete, Tubifex tubifex (Oligochaeta, Tubificidae), is capable of the auto‐tomization and regeneration of missing body parts. The posterior end of the worm is subject to autotomy (e.g., after predation or after exposure to toxic substances) and can be regenerated thereafter. Despite the ecological importance of T. tubifex, processes of autotomy and regeneration have been little studied. This work describes daily morphological and histological observations of caudal regeneration of this worm. We also compared regeneration processes when autotomy was induced by artificial transsection of the worms (control worms) and by exposure to copper ion, a frequently encountered environmental contaminant. The worms regenerated a functional posterior end (defecation possible) in 7 d as well as a prepygidial zone from which new segments could be regenerated. In T. tubifex, regeneration involved the presence of activated mesoblastocytes in the worm, increased number of neoblasts, and the increased migration of these cells. However, Cu2+ did not affect these processes, since no difference could be detected between regeneration of control and Cu‐autotomized worms.
Phylogeny of the Cocculinoidea (Mollusca, Gastropoda)
Authors: Strong Ellen E. , Harasewych M.G. , Haszprunar Gerhard
Published: August 2010

Abstract. The superfamily Cocculinoidea is a group of marine, deep‐water, limpet‐like gastropods. Recent speculation surrounding their affinities has concentrated on their placement within the Gastropoda. However, phylogenetic relationships within the Cocculinoidea, especially the monophyly of families and genera within the group, remain poorly understood. Phylogenetic analysis of 31 morphological characters for 15 cocculinoidean taxa and 2 outgroups resulted in a single most parsimonious tree, length=70, CI=0.62, and RI=0.71. Monophyly of the Cocculinoidea, Cocculinidae, and the genera Cocculina and Coccopigya was supported; Paracocculina and Coccocrater were found to be paraphyletic. Character optimization demonstrates that many characters often cited as diagnostic of various taxa, are often homoplastic and/or synapomorphies at different hierarchical levels.
Effects of biofilms on zebra mussel postveliger attachment to artificial surfaces
Authors: Kavouras Jerry H. , Maki James S.
Published: August 2010

Abstract. The zebra mussel is an introduced fouling organism in North American inland waters. This field study tested whether natural biofilms, formed by covering substrata with a 100‐μm mesh that allows microorganisms to attach and films to develop in the absence of postveligers, influenced the attachment of zebra mussel postveligers to artificial surfaces. Low‐wettable polycarbonate and wettable glass surfaces were used in the experiments over four field seasons to study biofilm formation (1997–1998) and mussel attachment (1998–2000). The presence of the mesh did not quantitatively affect biofilm development on either substratum as determined by microscopic direct counts and colony‐forming units on R2A agar. Natural biofilms on polycarbonate surfaces positively influenced postveliger attachment compared to substrata that initially had no film (ANOVA, p‐values ranged from ≤.05 to ≤.001). Biofilms did not influence postveliger attachment to glass surfaces (ANOVA, p>.05). Attachment to both substrata was similar on surfaces with and without previously settled postveligers. Based on these results, we conclude that biofilms can enhance postveliger attachment to some but not all artificial surfaces.
Gametogenesis and reproduction in Hormogaster elisae (Oligochaeta, Hormogastridae)
Authors: Garvín Marta H. , Trigo Dolores , Hernández Patricia , Cosín Darío J. Díaz
Published: August 2010

Abstract. The gametogenesis of the earthworm Hormogaster elisae, an endemic species of central Spain, was studied over a 12‐month period. The ovaries, seminal vesicles, male funnels, and spermathecae of 156 specimens were removed by dissection. Microscopic analysis of these organs allowed the study of the gametogenic cycle, and provided information on copulation method and reproductive cycle. Individuals of H. elisae have two pairs of spermathecae, the posterior of which is more important for the storage of sperm. In summer, the earthworms enter quiescence, and oogenesis and spermatogenesis are interrupted. The gametogenic processes occur mainly during autumn and winter. Ovules are produced during all months except August and September, and the spermathecae contain sperm over the full 12‐month period. There is a reproductive peak in spring, when most ovules are produced and the clitellum is most developed.
Autotomy and arm number increase in Oxycomanthus japonicus (Echinodermata, Crinoidea)
Authors: Shibata Tomoko F. , Oji Tatsuo
Published: August 2010

Abstract. We have explored the process by which crinoids increase arm number as they grow. Two hypotheses have been proposed: (1) arm autotomy with subsequent bifurcation and regeneration of a pair of arms, and (2) growth of a pinnule into an additional arm. We have traced the development of Oxycomanthus japonicus for about a year after fertilization and provide the first confirmation that the number of arms increases by autotomy, bifurcation, and subsequent regeneration of a pair of arms. The next such addition tends to occur at some distance from the previous pair. Thus, increase of arm number takes place in such a manner that the density of the arms remains relatively constant, and an efficient filtration fan for feeding is maintained. Although arm autotomy in crinoids has been considered to occur only as a response to physical or chemical disturbance, the present results suggest that autotomy also occurs as a specific, intrinsically programmed event during normal development.
Cladistic analysis of Medusozoa and cnidarian evolution
Authors: Marques Antonio C. , Collins Allen G.
Published: August 2010

Abstract. A cladistic analysis of 87 morphological and life history characters of medusozoan cnidarians, rooted with Anthozoa, results in the phylogenetic hypothesis (Anthozoa (Hydrozoa (Scyphozoa (Staurozoa, Cubozoa)))). Staurozoa is a new class of Cnidaria consisting of Stauromedusae and the fossil group Conulatae. Scyphozoa is redefined as including those medusozoans characterized by strobilation and ephyrae (Coronatae, Semaeostomeae, and Rhizostomeae). Within Hydrozoa, Limnomedusae is identified as either the earliest diverging hydrozoan lineage or as the basal group of either Trachylina (Actinulida (Trachymedusae (Narcomedusae, Laingiomedusae))) or Hydroidolina (Leptothecata (Siphonophorae, Anthoathecata)). Cladistic results are highly congruent with recently published phylogenetic analyses based on 18S molecular characters. We propose a phylogenetic classification of Medusozoa that is consistent with phylogenetic hypotheses based on our cladistic results, as well as those derived from 18S analyses. Optimization of the characters presented in this analysis are used to discuss evolutionary scenarios. The ancestral cnidarian probably had a sessile biradial polyp as an adult form. The medusa is inferred to be a synapomorphy of Medusozoa. However, the ancestral process (metamorphosis of the apical region of the polyp or lateral budding involving an entocodon) could not be inferred unequivocally. Similarly, character states for sense organs and nervous systems could not be inferred for the ancestral medusoid of Medusozoa.
Great Gordian knots: sex ratio and sexual size dimorphism in aggregations of horsehair worms (Gordius difficilis)
Authors: Cochran Philip A. , Newton Andrew K. , Korte Clare
Published: August 2010

Abstract. Large knots (>100 individuals) of adult horsehair worms (Gordius difficilis) were collected in several spring‐fed habitats in Wisconsin and Minnesota. These aggregations were dominated numerically by males. Although distributions of length and diameter of males and females overlapped, females tended to be significantly longer and wider than males. Moreover, at any given length, females were wider than males. These findings confirm and add statistical support to previously published reports.
The problem of similarity: analysis of repeated patterns of microsculpture on gastropod larval shells
Authors: Hickman Carole S.
Published: August 2010

Abstract. The problem of similarity is one of explaining the causes of striking resemblances between patterns and architectural themes that recur in organisms at various scales of biological organization. Classical explanations that have considered only the alternatives of homology and analogy overlook similarities of form that are primarily a consequence of fabrication, conveying little information about evolutionary relationships or functional role. When viewed at successively higher magnifications and when mapped onto a phylogeny, patterns of delicate cancellate microsculpture and granular microprotuberances on the surfaces of larval shells of marine gastropods fail to meet the predictions of exclusively historical or exclusively functional explanations, but are shown to be rich in fabricational information. Similar patterns suggest that early biomineralization of the initial organic shell is under weaker biological control than the processes that modulate assembly of the multi‐layered, hierarchically‐organized composite materials of the adult shell. Some patterns suggest remote biomineralization, without direct influence of living tissue. Scanning electron microscopy of larval shell features reveals previously undetected variation on basic themes that may have implications for the traditional disciplines of systematics, functional morphology, and fabricational morphology. The integration of the approaches of the traditional divisions of biology is required for full explanation of similarity and to generate a unified set of principles for the analysis of form in living and fossil organisms.
Anna Meyer and the distinction between grades and clades in early models of gastropod evolution
Authors: Lindberg David R. , Matzen Benjamin L.
Published: August 2010

Abstract. Anna Meyer published her first (and apparently last) scientific paper in 1913, in which she reported, in part, on the organization of the renogenital systems in the “Diotocardia” and “Monotocardia,” and the evolutionary signal present in this character suite. Meyer's phylogeny broke with conventional wisdom of her time and she reconstructed early gastropod evolution as a sequence of branching events rather than a continuous grade. Her phylogeny was ignored because it did not correspond to the well‐ordered grades that came to dominate gastropod systematics for over 75 years, but her schematics of renogenital configurations have been featured in the literature for over 55 years, sometimes without citation and redrawn to show a different set of relationships. We hope that the translation of her paper from German into English (http://www.ucmp.berkeley.edu/collections/archdat.html) will make her contribution more accessible to workers.
Phylogeny of North American amblemines (Bivalvia, Unionoida): prodigious polyphyly proves pervasive across genera
Authors: Campbell David C. , Serb Jeanne M. , Buhay Jennifer E. , Roe Kevin J. , Minton Russell L. , Lydeard Charles
Published: August 2010

Abstract. The subfamily Ambleminae is the most diverse subfamily of fresh‐water mussels (order Unionoida), a globally diverse and ecologically prominent group of bivalves. About 250 amblemine species occur in North America; however, this diversity is highly imperiled, with the majority of species at risk. Assessing and protecting this diversity has been hampered by the uncertain systematics of this group. This study sought to provide an improved phylogenetic framework for the Ambleminae. Currently, 37 North American genera are recognized in Ambleminae. Previous phylogenetic studies of amblemines highlighted the need for more extensive sampling due to the uncertainties arising from polyphyly of many currently recognized taxa. The present study incorporated all amblemine genera occurring in North America north of the Rio Grande, with multiple species of most genera, including the type species for all but seven genera. A total of 192 new DNA sequences were obtained for three mitochondrial gene regions: COI, 16S, and ND1. In combination with published data, this produced a data matrix incorporating 357 gene sequences for 143 operational taxonomic units, representing 107 currently recognized species. Inclusion of published data provides additional taxa and a summary of present molecular evidence on amblemine phylogeny, if at the cost of increasing the amount of missing data. Parsimony and Bayesian analyses suggest that most amblemine genera, as currently defined, are polyphyletic. At higher taxonomic levels, the tribes Quadrulini, Lampsilini, and Pleurobemini were supported; the extent of Amblemini and the relationships of some genera previously assigned to that tribe remain unclear. The eastern North American amblemines appear monophyletic. Gonidea and some Eurasian taxa place as probable sister taxa for the eastern North American Ambleminae. The results also highlight problematic taxa of particular interest for further work.
Species identification of bivalve‐inhabiting marine hydrozoans of the genus Eugymnanthea
Authors: Govindarajan Annette F. , Piraino Stefano , Gravili Cinzia , Kubota Shin
Published: August 2010

Abstract. Species‐level identification is difficult in the symbiotic bivalve‐inhabiting hydrozoans of the genus Eugymnanthea (Cnidaria, Hydrozoa). Morphological differences are detected only in the adult medusoid stage. Eugymnanthea is known only from the Mediterranean and the western Pacific, and doubt persists over whether the two localities are inhabited by different species. Because the bivalve host, Mytilus galloprovincialis, is thought to have been introduced by humans from the Mediterranean to the western Pacific, there has been speculation that the Mediterranean Eugymnanthea was also introduced along with its host. Here, we evaluate the species status of the two hydrozoan forms with breeding experiments, morphology, and two recently developed tools for discrimination: a mesoglea cell adhesion and spreading test, and 16S rDNA comparison. Reciprocal crosses of the two forms failed to produce normal offspring, providing evidence that they are indeed different species according to the biological species concept, and suggesting that the Pacific form is not an invasion of the Mediterranean form. The tissue‐grafting test failed to distinguish between the two forms, while the morphological and genetic evidence corroborated the breeding results.
Male occurrence in Austrian populations of Triops cancriformis (Branchiopoda, Notostraca) and ultrastructural observations of the male gonad
Authors: Scanabissi Franca , Eder Erich , Cesari Michele
Published: August 2010

Abstract. Recent reports of occasional males in Austrian populations of Triops cancriformis have promoted interest in an analysis of the ultrastructure of the male gonad. It appears as a double thick and well‐defined tubular structure running along the midgut, inside the hemocoel. It is composed of two portions: the wall and the lumen. The former is made up of germ cells that are widespread and intermixed with somatic cells. The lumen is ∼200 μm wide and acts as the collecting site of spermatids and sperm. The germ cells are recognizable by their rounded appearance and by the occurrence of exceptionally long synaptonemal complexes in their nuclei. Their maturation implies a volume elongation and an aggregation in a characteristic “cyst” arrangement. The cysts migrate towards the lumen, where they break open, releasing spermatids and sperm. At the end of this process the lumen is filled with maturing gametes. The sperm have very condensed chromatin nuclei and partially reduced cytoplasm where the most striking features are the axoneme and strewn microtubules together with evident pseudopodia. Our morphological data support the full functionality of males in T. cancriformis. However, further work on gametogenesis, distribution of sexes, and genetic analysis of breeding experiments are needed to reach a fuller understanding of the role of males in middle and northern European populations of this species.
Biology of a “babysitting” symbiosis in brittle stars: analysis of the interactions between Ophiomastix venosa and Ophiocoma scolopendrina
Authors: Fourgon Didier , Jangoux Michel , Eeckhaut Igor
Published: August 2010

Abstract. “Babysitting” symbioses between brittle star species involve juveniles of one species and adults of another. During this phenomenon, reported from many localities in the Indo‐Pacific Ocean, juveniles are attached to the disk or lie in the bursa of the adults. The symbiosis between members of Ophiomastix venosa and their host, Ophiocoma scolopendrina, was investigated on the Great Barrier Reef of Toliara (Madagascar) during a 14‐month period. The population of O. scolopendrina only occurs on rocky spurs that frequently emerge at low tide, while the population of O. venosa lies in adjacent surge channels that are always immersed. Only juveniles of O. venosa associated with adults of O. scolopendrina may occur on the rocky spurs. Analyses conducted on the populations of the two species showed that (1) the symbiosis is facultative and that symbiotic juveniles migrate into the channels when they reach a disc diameter of 6 mm, and (2) recruitment in the channels occurs in April. Host choice experiments, Y‐tube experiments, and experiments assessing the resistance of the ophiuroids to air‐drying were conducted in the laboratory. The experiments clearly demonstrated that (1) symbiotic juveniles of O. venosa specifically recognize adults of O. scolopendrina, while free juveniles of the same size do not, and (2) juveniles of O. venosa would not survive air‐drying conditions similar to those observed on the spurs at low tides if they were not in symbiosis with adults of O. scolopendrina.