Comparative immunohistochemistry of the cephalic sensory organs in Opisthobranchia (Mollusca,Gastropoda)

The structure and function of the central nervous systems of opisthobranch gastropods have been studied extensively. However, the organisation and function of the peripheral nervous system are poorly understood. The cephalic sensory organs (CSOs) are known to be chemosensory structures in the head region of opisthobranchs. In the present study, we used immunohistochemical methods and confocal laserscanning microscopy to comparatively examine the CSOs of different opisthobranchs, namely Acteon tornatilis, Aplysia punctata, Archidoris pseudoargus and Haminoea hydatis. We wanted to characterise sensory epithelia in order to infer the function of sensory structures and the organs they constitute. Immunoreactivity against the three antigens tyrosine hydroxylase, FMRFamide and serotonin was very similar in the CSOs of all investigated species. Tyrosine hydroxylase-like immunoreactivity was detected primarily in subepidermal sensory cell bodies, which were much more abundant in the anteriorly situated CSOs. This observation indicates that these cells and the respective organs may be involved in contact chemoreception and mechanoreception. The dominant features of FMRFamide-like immunoreactivity, especially in the posterior CSOs, were tightly knotted fibres which reveal glomerulus-like structures. This suggests an olfactory role for these organs. Serotonin-like immunoreactivity was detected in an extensive network of efferent fibres, but was not found within any peripheral cell bodies. Serotonin-like immunoreactivity was found in the same glomerulus-like structures as FMRFamide-like immunoreactivity, indicating a function of serotonin in the efferent control of olfactory inputs. Besides this functional implication, this study could also add some knowledge on the doubtful homology of the CSOs in opisthobranch gastropods.     

A comparative ultrastructural investigation of the cephalic sensory organs in Opisthobranchia (Mollusca, Gastropoda)

Cephalic sensory organs (CSOs) are specialised structures in the head region of adult Opisthobranchia involved in perception of different stimuli. The gross morphology of these organs differs considerably among taxa. The current study aims at describing the cellular morphology of the CSOs in order to reveal cellular patterns, especially of sensory epithelia, common for opisthobranchs. Transmission electron microscopy was used to characterise the fine structure of the organs and to compare the CSOs of four different opisthobranch species. The cellular composition of the sensory system is conserved among taxa. The epidermal cells in sensory regions are always columnar and ciliated cells are frequently apparent. The sensory cells are primary receptors arranged in subepidermal cell clusters. They extend dendrites which penetrate the epithelium and reach the surface. Some of the dendrites bear cilia, whereas others only build a small protuberance. Processing of sensory information takes place in the peripheral glomeruli of all species. Moreover, few taxa possess additional peripheral ganglia at the base of their CSOs. The results of the present study might support other investigations indicating that the posterior CSOs are primarily involved in distance chemoreception, whereas the anterior CSOs might be used for contact chemoreception and mechanoreception.     

Systematic position of the pelagic Thecosomata and Gymnosomata within Opisthobranchia (Mollusca, Gastropoda) – revival of the Pteropoda

The complete 18S (SSU) rRNA as well partial 28S (LSU) rRNA and partial mitochondrial COI sequences have been used to reconstruct the phylogenetic relationships within Opisthobranchia with special focus on the pelagic orders Thecosomata and Gymnosomata. Maximum parsimony, maximum likelihood, distance as well as Bayesian analysis of a combined dataset of the three genes reveals that Thecosomata and Gymnosomata are sister groups and together are closely related to Anaspidea. Possible sister taxon to Thecosomata, Gymnosomata and Anaspidea is Cephalaspidea s. str . Analysis of a taxon-extended dataset of partial 28S sequences supported a basal position of Limacina within Euthecosomata. Within Cavolinidae, Creseis is basal to the other taxa. Other phylogenetic implications from the present results are also discussed. Investigation of the morphology and histology of Thecosomata and Gymnosomata as well as several other opisthobranch taxa helped to identify autapomorphies for Thecosomata and Gymnosomata as well as apomorphies for the clades including these taxa.     

Ultrastructural and histochemical study of the salivary glands of Aplysia depilans (Mollusca, Opisthobranchia)

The digestive system of the sea hare, Aplysia depilans , includes a pair of ribbon-shaped salivary glands. A central duct and a large blood vessel run close to each other along the length of these glands and both are surrounded by a layer of muscle cells. Three cell types form the glandular epithelium: granular cells, vacuolated cells and mucocytes. The granular cells possess cilia and spherical secretion granules, located primarily in the apical region. The granules of immature cells have a low electron density and are mainly formed by neutral polysaccharides with small amounts of proteins. The granules of mature cells are larger, have a high electron density and are mainly formed by proteins with lower amounts of neutral polysaccharides. Transition stages between immature and mature granular cells are observed. The vacuolated cells are large and frequently pyramidal in shape, but after the application of histochemical techniques almost all vacuoles remain uncoloured. The numerous vacuoles contain flocculent material in a clear background and the mitochondria possess large crystalline structures in the matrix. A pyramidal shape is also typical of the mucocytes, which are filled with vesicles containing granular masses surrounded by a network of secretion material. These large cells are strongly stained by Alcian blue, revealing the presence of acidic mucopolysaccharides. This is the first ultrastructural study of the salivary glands in opisthobranch gastropods.     

Here be dragons – phylogeography of Pteraeolidia ianthina (Angas, 1864) reveals multiple species of photosynthetic nudibranchs (Aeolidina: Nudibranchia)

The aeolid Pteraeolidia ianthina (Angas, 1864) is a strikingly‐coloured aeolid nudibranch, informally known as the ‘Blue Dragon’. It is recognised as an unusually widespread Indo‐Pacific species, with variation in colouration and morphology, and biogeographic differences in zooxanthellae (dinoflagellate symbionts of the genus Symbiodinium). This variation hints at possible cryptic species, which was tested here using phylogenetic analyses of mitochondrial DNA data (COI, 16S). Our results showed multiple well‐supported clades with slight but consistent differences in radular morphology and colouration, and thus we clarify one of the three available names. A temperate NSW clade showed a more elongate and pointed central radular tooth and lacked white body colouration, in comparison to a more variable tropical clade, which had a shorter and more blunt central tooth. The type locality of Pteraeolidia ianthina is Sydney Harbour, New South Wales (NSW), Australia, and according to our study, does not occur outside NSW. Pteraeolidia semperi (Bergh, 1870) and P. scolopendrella (Risbec, 1928) are removed from synonymy with P. ianthina. Wider phylogeographic sampling is required before resolving the availability of the two remaining names, and subclades within the tropical clade, but there is evidence to suggest multiple cryptic species exist. The biogeographic differences in symbionts, and the importance of their role in life history, suggests that changes in symbiosis may have helped drive divergence via local adaptation in the host nudibranchs. © 2015 The Linnean Society of London     

Evolution of the Sacoglossa (Mollusca, Opisthobranchia) and the ecological associations with their food plants

Evolution in the opisthobranch order Sacoglossa has been closely linked to their specialized suctorial herbivorous habits. All shelled Sacoglossa (about 20% of the species) feed on one algal genus, Caulerpa. The non-shelled Sacoglossa have 'radiated' to other diets, mainly siphonalean or septate green algae (Class Ulvophyceae). Comparing the phylogeny of sacoglossan genera with the phylogeny of the Ulvophyceae indicates that co-speciation may have taken place at the basal node of the Sacoglossa, and that host switching has taken place several times in the two non-shelled clades. It is suggested that the most important evolutionary process has been speciation by 'resource-tracking'; the resource tracked is most probably cell wall composition of the algal prey. The fossil record of extant sacoglossan genera dates back to the Eocene and, based on the fossil record of siphonalean green algae, the Sacoglossa most likely appeared in the Cretaceous. It is hypothesized that the ancestral sacoglossan was epifaunal, suctorial and herbivorous, and the 'ancestral' food plant was not Caulerpa, but filamentous, calcified, now extinct, Udoteaceae.     

The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: Chromodoris splendida, C. aspersa and Hypselodoris placida colour groups

Eleven species of Chromodoris, two species of Hypselodoris, three species of Mexichromis and one species of Noumea are described from the Indo-West Pacific, of which four species of Chromodoris and one of Mexichromis are new species. All species have a colour pattern dominated by red, purple or black spots. All previously described species with similar colour patterns, from both the Indo-West Pacific and other regions, are discussed.     

The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: the genus Glossodoris Ehrenbergh (= Casella, H. & A. Adams)

The genus Glossodoris Ehrenberg is reviewed and 28 species are placed in the genus. Seventeen species are fully described and of these, seven are named as new species. Four others are considered new to science, but insufficient material is available to name them. Published information on a further 11 species is included as is a discussion on phylogenetic trends within the genus.     

Genesis and structure of the so-called “balbiani body” or “yolk nucleus” in the oocyte of dugesia dorotocephala (turbellaria,tricladida)

Oogenesis of the fresh-water triclad Dugesia dorotocephala has been studied by electron microscopical methods, with particular regard to the genesis and composition of the so-called “Balbiani body.” Its origin is clearly recognizable in young oocytes where the few mitochondria present seem to gather at the level of the perinuclear ooplasm. Here they surround dense masses of finely granular, fibrillar material probably coming from the nucleus. During the previtelloge ic period, mitochondria rapidly increase in number while the dense masses progressively dissolve. In the vitellogenic oocytes the Balbiani body shows its final configuration: it appears as a large area (up to 15-20 pm in diameter) consisting of innumerable densely packed mitochondria, some smooth vesicles and free ribosomes. This aggregate of cytoplasmic organelles remains unmodified in the mature oocytes. The function of the “Balbiani body” of D. dorotocephala is as yet unclear; it can only be asserted that it is not correlated with yolk production in which the endoplasmic reticulum and the Golgi complex are involved.     

Geographic and habitat partitioning of genetically distinct zooxanthellae (Symbiodinium) in Acropora corals on the Great Barrier Reef

Intra- and intercolony diversity and distribution of zooxanthellae in acroporid corals is largely uncharted. In this study, two molecular methods were applied to determine the distribution of zooxanthellae in the branching corals Acropora tenuis and A. valida at several reef locations in the central section of the Great Barrier Reef. Sun-exposed and shaded parts of all colonies were examined. Single-stranded conformational polymorphism analysis showed that individual colonies of A. tenuis at two locations harbour two strains of Symbiodinium belonging to clade C (C1 and C2), whereas conspecific colonies at two other reefs harboured a single zooxanthella strain. A. valida was found to simultaneously harbour strains belonging to two distinct phylogenetic clades (C and D) at all locations sampled. A novel method with improved sensitivity (quantitative polymerase chain reaction using Taqman fluorogenic probes) was used to map the relative abundance distribution of the two zooxanthella clades. At two of the five sampling locations both coral species were collected. At these two locations, composition of the zooxanthella communities showed the same pattern in both coral species, i.e. correlation with ambient light in Pioneer Bay and an absence thereof in Nelly Bay. The results show that the distribution of genetically distinct zooxanthellae is correlated with light regime and possibly temperature in some (but not all) colonies of A. tenuis and A. valida and at some reef locations, which we interpret as acclimation to local environmental conditions.     

“Capacity”, “best interests”, “will and preferences” and the UN Convention on the Rights of Persons with Disabilities

The United Nations (UN) Convention on the Rights of Persons with Disabilities (CRPD) is the most up‐to‐date international legal instrument concerning the rights of persons with disabilities. Such persons are taken to include those with serious mental disorders. According to an authoritative interpretation of a crucial Article (Article 12 ‐ Equal recognition before the law) by the UN CRPD Committee, involuntary detention and treatment of people with mental health disabilities are prohibited under the Convention. Both conventional mental health law and “capacity‐based” law are deemed to violate the Convention. However, some other UN bodies are not in full agreement (for example, the UN Human Rights Committee and the Subcommittee on Prevention of Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment), while others are less explicitly absolutist (for example, the Human Rights Council). Furthermore, strong criticisms of the position of the CRPD Committee have been mounted from a number of academic quarters. These criticisms center on whether the role of a person's ability to make a decision can be ignored, no matter the circumstances. Much of the above debate turns on the concept of “legal capacity” and the now often‐repeated precept that one must always respect the “will and preferences” of the person with a disability. However, “will and preferences” remains undefined. In this paper, I offer an analysis of “will and preferences” that can clarify interventions that may be acceptable or non‐acceptable under the terms of the UN Convention.     

Preliminary Observations on the Nature,Taxonomic Composition,Distribution, Behaviour and Nutrient Requirements of the “Unusual” Algal “Jellies” of Oguta Lake in Southeastern Nigeria

Preliminary observations were made between October 1982 and May 1983 on the nature, taxonomic composition, spatial distribution, buoyancy behaviour and nutrient requirements of some unusual planktonic algal “jellies” in Oguta Lake in Southeastern Nigeria. These “jellies” are macroscopic, blue-green algal masses whose excessive mucilage of high consistency acts as substrata for other epiphytic components viz. diatoms and green algae. They are more abundant in the lentic areas of the lake, undergo diurnal vertical movements and have their growth enhanced by spikes of nitrogen and phosphorus salts into their aquatic medium. The effects of these “jellies” on the ecology and general water use of the lake are discussed. Speculations on the reasons for their occurrence are given and possible control measures outlined.     

Diurnal changes in the photochemical efficiency of the symbiotic dinoflagellates (Dinophyceae) of corals: photoprotection, photoinactivation and the relationship to coral bleaching

The photochemical efficiency of symbiotic dinoflagellates within the tissues of two reef‐building corals in response to normal and excess irradiance at water temperatures < 30 °C were investigated using pulse amplitude modulated (PAM) chlorophyll fluorescence techniques. Dark‐adapted F_v/F_m showed clear diurnal changes, decreasing to a low at solar noon and increasing in the afternoon. However, F_v/F_m also drifted downwards at night or in prolonged darkness, and increased rapidly during the early morning twilight. This parameter also increased when the oxygen concentration of the water holding the corals was increased. Such changes have not been described previously, and most probably reflect state transitions associated with PQ pool reduction via chlororespiration. These unusual characteristics may be a feature of an endosymbiotic environment, reflective of the well‐documented night‐time tissue hypoxia that occurs in corals. F_v/F_m decreased to 0·25 in response to full sunlight in shade‐acclimated (shade) colonies of Stylophora pistillata, which is considerably lower than in light‐acclimated (sun) colonies. In sun colonies, the reversible decrease in F_v/F_m was caused by a lowering of F_m and F_o suggesting photoprotection and no lasting damage. The decrease in F_v/F_m, however, was caused by a decrease in F_m and an increase in F_o in shade colonies suggesting photoinactivation and long‐term cumulative photoinhibition. Shade colonies rapidly lost their symbiotic algae (bleached) during exposure to full sunlight. This study is consistent with the hypothesis that excess light leads to chronic damage of symbiotic dinoflagellates and their eventual removal from reef‐building corals. It is significant that this can occur with high light conditions alone.     

Development of the transgenic cyan fluorescent protein (CFP)‐expressing nude mouse for “Technicolor” cancer imaging

A major goal for in vivo biology is to develop models which can express multiple colors of fluorescent proteins in order to image many processes simultaneously in real time. Towards this goal, the cyan fluorescent protein (CFP) nude mouse was developed by crossing non‐transgenic nude mice with the transgenic CK/ECFP mouse in which the β‐actin promoter drives expression of CFP in almost all tissues. In crosses between nu/nu CFP male mice and nu/+ CFP female mice, approximately 50% of the embryos fluoresced blue. In the CFP nude mice, the pancreas and reproductive organs displayed the strongest fluorescent signals of all internal organs which vary in intensity. Orthotopic implantation of XPA‐1 human pancreatic cancer cells expressing red fluorescent protein (RFP); or green fluorescent protein (GFP) in the nucleus and RFP in the cytoplasm, was performed in female nude CFP mice. Color‐coded fluorescence imaging of these human pancreatic cancer cells implanted into the bright blue fluorescent pancreas of the CFP nude mouse afforded novel insight into the interaction of the pancreatic tumor and the normal pancreas, in particular the strong desmoplastic reaction of the tumor. The naturally enhanced blue fluorescence of the pancreas in the CFP mouse serves as an ideal background for color‐coded imaging of the interaction of implanted cancer cells and the host. The CFP nude mouse will provide unique understanding of the critical interplay between the cancer cells and their microenvironment. J. Cell. Biochem. 107: 328–334, 2009. © 2009 Wiley‐Liss, Inc.     

The Chromodorididae (Opisthobranchia: Mollusca) of the Indo-West Pacific: further species of Glossodoris, Thorunna and the Chromodoris aureomarginata colour group

Nineteen species of chromodorid nudibranchs from the Indo-West Pacific are described including 12 new to science. There are four new species of Glossodoris and one new species of Thorunna . The anatomy of two other species of Thorunna, T. daniellae and T. florens , is described and the problematical 'Hypselodoris' kulonba Burn, 1966 is shown to belong to the genus Digidentis. New species of chromodorids which are white with a yellow or red margin. or markings. from the genera Durvilledoris. Noumea and Cadlina are also described. Notes on colour variation in Glossodoris pallida and Chromodoris splendida are included.     

Integration of “Innate” and “Learned” Components within the IRME for Mussel Recognition in the European Bitterling Rhodeus amarus (Bloch)

The European bitterling (Rhodeus amarus Bloch) practises a rather unusual method of spawning by using the favorable conditions in the gills of a living freshwater mussel (genera Unio and Anodonta) for the embryonic development of its fry. The capacity of mussel recognition was studied in inexperienced individuals with the aid of simultaneous preference tests in which pairs of dummies with increasing similarity to mussels were presented to the animals. The frequency of mussel-referred motor patterns, which were supposed to be species-specific (Wiepkema 1961), supplied the evaluation criterion. The results revealed a hierarchy of effectiveness within the class of relevant stimuli and showed certain effects of additivity typical of an Innate Releasing Mechanism or IRM. By far the most effective stimulus consisted in the specific smell of the mussel which is composed of at least three constituents (protein, hyaluronic acid, ammonium). The water flow itself, produced by the mussel in order to maintain nutritive and respiratory functions, was effective depending on its velocity (3 < v < 12 cm/s), its orientation (suction produced no effect), its direction (vertical > horizontal) and the shape of its field (oval). Within the visual modality only two simple perceptory patterns could be detected (dark spot on a clearer surface, straight horizontal edge), but the visual shape of the mussel as a whole was ignored by inexperienced individuals. Nevertheless the bitterlings are able to learn the shape when exposed to a living mussel and, in addition, it was even possible to condition the animals to an artificial object (inverted pot of clay) by using the mussel-smell flow as a reinforcing stimulus. The final discussion deals with the question of whether it is possible to interpret these “innate” respectively “learned” components of the IRME as sensory counterparts of behavioral structures which simply serve different functions by referring to correspondingly different sectors of the environment. In such a case the epistemological dichotomy regularly associated with the notions of “innate” (= “pre-given phylogenetical knowledge”) and “learned” (= “cognitive increase during ontogeny”) would suffer incisive questioning.     

Assessment of photosynthetic performance in the two life history stages of Alaria crassifolia (Laminariales,Phaeophyceae)

Understanding of the physiological responses of kelp to environmental parameters is crucial, especially in the context of environmental change that may have contributed to the decline of kelp forests all over the world. The current study presents the photosynthetic characteristics of the macroscopic sporophyte and microscopic gametophyte stages of the brown alga Alaria crassifolia from Hokkaido, Japan, as determined by examining their photosynthetic responses over a range of temperature and irradiance using dissolved oxygen and chlorophyll fluorescence measurements. Net photosynthetic rates of the sporophyte were consistently higher than those of gametophyte across temperature gradients and irradiance levels. Photosynthesis–irradiance curves at 8°C, 16°C, and 20°C revealed similar initial slopes (α = 0.4–0.9) on the two life history stages, but higher compensation (E _c = 4–7 μmol photons m^?2 s^?1) and saturation irradiances (E _k = 53–103 μmol photons m^?2 s^?1) for the sporophyte than for the gametophyte (E _c = 0–7 μmol photons m^?2 s^?1; E _k = 7–10 μmol photons m^?2 s^?1). Both stages exhibited chronic photoinhibition, as shown by the failure of recovery in their maximum quantum yields (F _v/F _m) following high irradiance stress, with greater possibility of photodamage at low temperature. Gametophytes were less sensitive to low temperatures than sporophytes, given their relatively stable F _v/F _m response. Nevertheless, temperature optima for photosynthesis of both stages coincide with each other at 20–23°C, which correspond to the growth and maturation periods of A. crassifolia in Japan. This species is also likely to suffer from thermal inhibition as both GP rates and F _v/F _m decreased above 24°C.     

Adaptation of Bathynellacea (Crustacea,Syncarida) to Life in the Interstitial (“Zoea Theory”)

This study aims at demonstrating that the Bathynellacea arose by neoteny from a zoea-like ancestor (“Zoea Theory”). Bathynellacea basically have a larval morphology. Their post-embryonic development passes through phases which are directly comparable with some in the development of primitive Eucarida. These phases are called the parazoeal and bathynellid phase, and correspond to the protozoeal and zoeal phase of Penaeidea, respectively. Running initially parallel to that of Penaeidea, the development of the Bathynellacea breaks off precociously. They reach sexual maturity at a stage which, in the Penaeidea, is followed by metamorphosis. There are reasons to assume that the development of all Syncarida originally passed through a series of free-living larval stages and underwent metamorphosis. The bathynellaceans reach adulthood at a stage which corresponds to the last larval stage of their ancestor. The ecological path to interstitial life of the Bathynellacea and the bearing of the “Zoea Theory” upon views as to their phylogenetic position are discussed. The classical example of a group of crustaceans thought to have arisen by neoteny, the Cladocera, is critically examined and found to be in need of reevaluation.     

“Prolonged grief disorder” and “persistent complex bereavement disorder”, but not “complicated grief”, are one and the same diagnostic entity: an analysis of data from the Yale Bereavement Study

There exists a general consensus that prolonged grief disorder (PGD), or some variant of PGD, represents a distinct mental disorder worthy of diagnosis and treatment. Nevertheless, confusion remains over whether different names and proposed symptom criteria for this disorder identify the same or different diagnostic entities. This study aimed to determine whether PGD, complicated grief (CG), and persistent complex bereavement disorder (PCBD) as described by the DSM‐5 are substantively or merely semantically different diagnostic entities. Data were derived from the Yale Bereavement Study, a longitudinal community‐based study of bereaved individuals funded by the US National Institute of Mental Health, designed explicitly to evaluate diagnostic criteria for disordered grief. The results suggested that the difference between PGD and PCBD is only semantic. The level of agreement between the original PGD test, a new version of the PGD test proposed for ICD‐11 and the PCBD test was high (pairwise kappa coefficients = 0.80‐0.84). Their estimates of rate of disorder in this community sample were similarly low (～10%). Their levels of diagnostic specificity were comparably high (95.0‐98.3%). Their predictive validity was comparable. In contrast, the test for CG had only moderate agreement with those for PGD and PCBD; its estimate of rate of disorder was three‐fold higher (～30%); its diagnostic specificity was poorer, and it had no predictive validity. We conclude that PGD, PCBD and proposed ICD‐11, but not CG, symptom‐diagnostic tests identify a single diagnostic entity. Ultimately, brief symptom‐diagnostic tests, such as the one proposed here for ICD‐11, may have the greatest clinical utility.