Utilization of polychaete tubes as spawning substrate by the sea raven Hemitripterus villosus (Scorpaeniformes)

Synopsis The sea raven, Hemitripterus villosus, deposits its eggs on polychaete tubes (Salmacina sp.) in the coastal waters of Usujiri, southern Hokkaido, Japan. This is contradictory to investigations in the Bay of Peter the Great, Soviet Union, where eggs are deposited in narrow clefts. The egg masses are found among the bunchy worm tubes or between the base of the colony and the substrate. The spawning habit of H. villosus is distinct from ‘spawner in live invertebrates’ such as the little dragon sculpin Blepsias cirrhosus, which specifically associates with a sponge. That of H. villosus is classified as a ‘cavity spawner’.     

On the biology of Blepsias cirrhosus (Hemitripteridae) from coastal waters of northern Primorye

Data on the distribution, size-age composition, dates, and conditions of spawning, fecundity, and feeding of Blepsias cirrhosus from the coastal waters of northern Primorye are presented. It is demonstrated that individuals in this region reach a length of 19.5 cm, weight of 87.0 g, and age of 6 years. Spawning occurs in the first half of July in coastal reefs at a water temperature of 10–15°C, at depths down to 8 m. The nuptual color of females is described. In connection with a clearly pronounced care for progeny, fecundity is low, 234–404 eggs. B. cirrhosus feeds mainly on nekton and benthic crustaceans.     

The motile escape response of a sessile prey: A sponge-scallop mutualism

The association of the sponges Myxilla incrustans (Esper) and Mycale adhaerens (Lambe) with the scallops Chlamys hastata hericia Gould and C. rubida (Hines) is shown to be a mutualism, which protects the sponges from predatory sponge-rasping dorid nudibranchs and the scallops from predatory starfish. The sponge is protected by scallop motility (also shown for the Suberites ficus-hermit crab association). The sponge helps to protect the scallops by altering the surface texture of the shell so increasing the efficacy of the swimming escape response by decreasing the adhesive abilities of asteroid tube-feet. The sponge also provides tactile camouflage against certain predatory starfish. There was no evidence that either component chemically deceived or repelled the predators of the other component. Predation pressure on both components of the association appears to be the major force leading to the mutualism.     

Evasive behaviour of a frog in response to bat predation

Chorusing frogs (Physalaemus pustulosus) visually detect hunting bats (Trachops cirrhosus) and models of T. cirrhosus on all but the darkest nights. Detection is apparently communicated rapidly, since all frogs in the area can quit calling withing less than a second of a T. cirrhosus arrival at the pond. Physalaemus pustulosus choruses remain silent longer following trials when a T. cirrhosus model is passed overhead than following normal shutdowns or those caused by a model of a small insectivorous bat. They often do not reduce calling in response to the normal activities of small bats.     

PHENOTYPIC PLASTICITY INDUCED IN TRANSPLANT EXPERIMENTS IN A MUTUALISTIC ASSOCIATION BETWEEN THE RED ALGA JANIA ADHAERENS (RHODOPHYTA,CORALLINALES) AND THE SPONGE HALICLONA CAERULEA (PORIFERA: HAPLOSCLERIDA): MORPHOLOGICAL RESPONSES OF THE ALGA1

The association between the red macroalga Jania adhaerens J. V. Lamour. and the sponge Haliclona caerulea is the most successful life‐form between 2 and 4 m depth in Mazatlán Bay (Mexican Pacific). J. adhaerens colonizes the rocky intertidal area and penetrates into deeper areas only when it lives in association with H. caerulea. The aposymbiotic form of the sponge has not been reported in the bay. To understand the ecological success of this association, we examined the capacity of J. adhaerens to acclimate in Mazatlán Bay using transplant experiments. The transplanted aposymbiotic J. adhaerens did not survive the first 2 weeks; however, J. adhaerens when living in association with H. caerulea, acclimated easily to depth, showing no sign of mortality during the 103 d of the experiment. We conclude that the ability of J. adhaerens to colonize in deeper areas in this hydrodynamic environment may in part rely on the protection provided by the sponge to the algal canopy. Both species contribute to the shape of the associated form. Nevertheless, the morphological variation in the association appears to be dominated by the variation in J. adhaerens canopy to regulate pigment self‐shading under light‐limited conditions and/or tissue resistance under high hydrodynamics. Consequently, our results are consistent with light as the abiotic controlling factor, which regulates the lower depth distribution of the association in Mazatlán Bay, through limiting the growth rate of J. adhaerens. Hydrodynamics may determine the upper limit of the association by imposing high mass losses.     

Study of Bacillus subtilis Endospores in Soil by Use of a Modified Endospore Stain

The Schaeffer-Fulton endospore stain was modified so that it would stain Bacillus subtilis endospores in soil smears. The modified stain differentiated among dormant spores, spores undergoing activation, and spores which had germinated but had not yet shown outgrowth. These differentiations were seen for spores in soil and for pure spore preparations in the laboratory. This stain was used to show reversible B. subtilis spore activation promoted by an Ensifer adhaerens-like indigenous bacterium in soil and by pure cultures of E. adhaerens added to spores in the laboratory. Under the specific conditions in the laboratory, spore germination did not proceed beyond the activation stage, and relatively little change occurred in the numbers of both E. adhaerens and B. subtilis. This was also true in soil, although some germination with destruction of spores and vegetative cells did occur if the soil had been nutritionally enriched by preincubation with incorporated ground alfalfa.     

Embryonic development and newly hatched larvae of the little dragon sculpinBlepsias cirrhosus

This paper describes both embryonic development and newly hatched larval morphology of the little dragon sculpinBlepsias cirrhosus. The eggs ofB. cirrhosus are almost spherical, 3.0–3.2 mm in diameter, and have a yolk color of burnt orange. Development is very slow, being especially sluggish once the embryo appears. The embryo begins forming from the 10th day. In size, the early embryo is less than 1/6 of the yolk’s circumference. Incubation at 10°C takes about 200 days, 50 days shorter than the incubation period in a natural environment, with a mean water temperature of 11°C. The notochord length of newly-hatched larvae averages 11.1 mm. The larvae are developed so fully that the notochord is already flexing and the caudal and pectoral rays are forming.     

Ensifer adhaerens Predatory Activity Against Other Bacteria in Soil, as Monitored by Indirect Phage Analysis

An indirect phage analysis procedure was used to detect and follow the activity of the bacterial predator Ensifer adhaerens in situ in natural soil. The soil was percolated with an aqueous suspension of washed bacterial host cells so that the E. adhaerens cells naturally present in the soil would multiply in response to the host cells. The natural phage development which ensued against these multiplying E. adhaerens cells in the soil was then monitored by noting plaques which developed when the percolation fluid was plated with laboratory strains of E. adhaerens on laboratory media. The activities of the other members of the predation system that includes E. adhaerens (Streptomyces sp. strain 34 and a myxobacter) could not be monitored directly by phage analysis because phage were not found for them. Indirect monitoring was possible, however, because they were susceptible to attack by E. adhaerens. In general, the results were in agreement with previous observations by other methods of the predation sequence. E. adhaerens attacked Micrococcus luteus, Streptomyces sp. strain 34, and the myxobacter but did not attack several other possible species of hosts. It also did not respond to percolation of the soil with various nutrient solutions. E. adhaerens phage activity was not present in half of the soils percolated with M. luteus cells. This seemed to reflect too great a phage-host specificity for the technique as regards these soils, because E. adhaerens-like bacteria other than the strains used for plaquing were present in at least some of these soils. Although E. adhaerens did not attack Escherichia coli or Pseudomonas aeruginosa in soil, there was an overproduction of E. adhaerens phage if these bacteria were percolated simultaneously with M. luteus cells. The possibility is discussed that this represents an activation by M. luteus (or by a heat-extractable factor from it) of other bacterial predators that attack E. coli or P. aeruginosa and that these predators subsequently are themselves attacked by E. adhaerens.     

Upregulation of DNA repair genes and cell extrusion underpin the remarkable radiation resistance of Trichoplax adhaerens

Trichoplax adhaerens is the simplest multicellular animal with tissue differentiation and somatic cell turnover. Like all other multicellular organisms, it should be vulnerable to cancer, yet there have been no reports of cancer in T. adhaerens or any other placozoan. We investigated the cancer resistance of T. adhaerens, discovering that they are able to tolerate high levels of radiation damage (218.6 Gy). To investigate how T. adhaerens survive levels of radiation that are lethal to other animals, we examined gene expression after the X-ray exposure, finding overexpression of genes involved in DNA repair and apoptosis including the MDM2 gene. We also discovered that T. adhaerens extrudes clusters of inviable cells after X-ray exposure. T. adhaerens is a valuable model organism for studying the molecular, genetic, and tissue-level mechanisms underlying cancer suppression.

The placozoan Trichoplax adhaerens is able to tolerate high levels of radiation and is resilient to DNA damage; this study reveals that exposure to X-rays triggers the extrusion of cell clusters which subsequently die, and that radiation exposure induces the overexpression of genes involved in DNA repair.     

Nitrogen-Fixing Nodules with Ensifer adhaerens Harboring Rhizobium tropici Symbiotic Plasmids

Ensifer adhaerens is a soil bacterium that attaches to other bacteria and may cause lysis of these other bacteria. Based on the sequence of its small-subunit rRNA gene, E. adhaerens is related to Sinorhizobium spp. E. adhaerens ATCC 33499 did not nodulate Phaseolus vulgaris (bean) or Leucaena leucocephala, but with symbiotic plasmids from Rhizobium tropici CFN299 it formed nitrogen-fixing nodules on both hosts. The nodule isolates were identified as E. adhaerens isolates by growth on selective media.     

The little dragon sculpinBlepsias cirrhosus,another case of internal gametic association and external fertilization

In the copulating cottid species,Blepsias cirrhosus, the point at which fertilization occurred was determined experimentally. Ovulated eggs were obtained directly from the ovary of impregnated females. Eggs maintained in ovarian fluid did not show any signs of development, whereas most of the eggs which had been placed in seawater had developed to the 4-cell stage after 24hrs. The eggs kept in ovarian fluid initiated segmentation when later transferred into seawater. Histological examination showed that a number of spermatozoa had entered the micropyle, but that penetration did not occur in eggs that were not immersed in seawater. In these eggs, the metaphase spindle of the second meiotic division was observed in the ooplasm, at the animal pole. These results indicate that, in impregnated females, the spermatozoa associate with the eggs in the ovarian cavity, but that fertilization occurs externally when the eggs are spawned.     

Biodegradation of the neonicotinoid insecticide thiamethoxam by the nitrogen-fixing and plant-growth-promoting rhizobacterium Ensifer adhaerens strain TMX-23

Thiamethoxam (THIA), a second generation neonicotinoid insecticide in the thianicotinyl subclass, is used worldwide. Environmental studies revealed that microbial degradation is the major mode of removal of this pesticide from soil. However, microbial transformation of THIA is poorly understood. In the present study, we isolated a bacterium able to degrade THIA from rhizosphere soil. The bacterium was identified as Ensifer adhaerens by its morphology and 16S ribosomal DNA sequence analysis. High-performance liquid chromatography and mass spectrometry analysis suggested that the major metabolic pathway of THIA in E. adhaerens TMX-23 involves the transformation of its N-nitroimino group (=N–NO₂) to N-nitrosoimino (=N–NO) and urea (=O) metabolites. E. adhaerens TMX-23 is a nitrogen-fixing bacterium harboring two types of nifH genes in its genome, one of which is 98 % identical to the nifH gene in the cyanobacterium Calothrix sp. MCC-3A. E. adhaerens TMX-23 released various plant-growth-promoting substances including indole-3-acetic acid, exopolysaccharides, ammonia, HCN, and siderophores. Inoculation of E. adhaerens TMX-23 onto soybean seeds (Glycine max L.) with NaCl at 50, 100, or 154 mmol/L increased the seed germination rate by 14, 21, and 30 %, respectively. THIA at 10 mg/L had beneficial effects on E. adhaerens TMX-23, enhancing growth of the bacterium and its production of salicylic acid, an important plant phytohormone associated with plant defense responses against abiotic stress. The nitrogen-fixing and plant-growth-promoting rhizobacterium E. adhaerens TMX-23, which is able to degrade THIA, has the potential for bioaugmentation as well as to promote growth of field crops in THIA-contaminated soil.     

Effects of sponge and barnacle encrustation on survival of the scallop <Emphasis Type="Italic">Chlamys hastata</Emphasis>

The scallop Chlamys hastata frequently carries epibionts such as sponges and barnacles on its shells. Although the scallop-sponge relationship has been characterized as a mutualism, little is known about the scallop-barnacle relationship. This study investigated the effects of sponge and barnacle encrustation on the ability of C. hastata to avoid predation by the sea star Pycnopodia helianthoides. In feeding trials, P. helianthoides caught and consumed significantly more barnacle-encrusted scallops (7.7 ± 0.8 out of 20 scallops) than scallops encrusted by either of the sponges Myxilla incrustans (4.1 ± 0.9) or Mycale adhaerens (3.0 ± 0.5). Epibiont-free scallops (5.7 ± 0.5) formed an intermediate treatment between barnacle-encrusted and sponge-encrusted scallops. Possible mechanisms by which the sponges protected the scallops were investigated in two ways: two feeding trials were videotaped to allow qualitative analysis of sea star and scallop behavior and sea star feeding responses to scallop and sponge homogenates were determined to investigate if sea stars accept scallops and sponges as prey. Sea stars displayed positive feeding responses to scallop puree 97.5% ± 1.6 of the time while only displaying positive responses to Mycale adhaerens homogenate 4.4% ± 2.0 of the time and to Myxilla incrustans homogenate 4.4% ± 2.9 of the time. The videotaped feeding trials indicated that interference with tube feet adhesion by the sponge deterred predation. Observations of both sea stars that were videotaped showed that neither avoided trying to capture sponge-encrusted scallops, and at no time was a captured scallop willingly released by the sea stars. Thus, it appears that sponges provide tactile-mechanical protection and possibly chemical or tactile camouflage in this predator/prey relationship. Finally, the effects of sponge encrustation on barnacle settlement were determined. Field experiments showed that barnacle larvae settled more frequently on epibiont-free scallops than on those with either of the two sponges, potentially protecting the scallops from an epibiont that increases the scallop’s susceptibility to predation. Handling editor: K. Martens     

Polycoccum crespoae sp. nov., the first report of a lichenicolous fungus on Chondropsis semiviridis (Parmeliaceae)

Abstract:Polycoccum crespoae sp. nov. is described from thalli of Chondropsis semiviridis collected in Australia (Victoria). It has consistently 4-spored asci but differs from known 4-spored species in the size and shape of the ascospores. Attention is also drawn to another undescribed Polycoccum found on another genus ofParmeliaceae , Karoowia adhaerens, from South Africa (Cape Province).     

JUNCTIONAL COMPLEXES IN VARIOUS EPITHELIA

The epithelia of a number of glands and cavitary organs of the rat and guinea pig have been surveyed, and in all cases investigated, a characteristic tripartite junctional complex has been found between adjacent cells. Although the complex differs in precise arrangement from one organ to another, it has been regularly encountered in the mucosal epithelia of the stomach, intestine, gall bladder, uterus, and oviduct; in the glandular epithelia of the liver, pancreas, parotid, stomach, and thyroid; in the epithelia of pancreatic, hepatic, and salivary ducts; and finally, between the epithelial cells of the nephron (proximal and distal convolution, collecting ducts). The elements of the complex, identified as zonula occludens (tight junction), zonula adhaerens (intermediary junction), and macula adhaerens (desmosome), occupy a juxtaluminal position and succeed each other in the order given in an apical-basal direction. The zonula occludens (tight junction) is characterized by fusion of the adjacent cell membranes resulting in obliteration of the intercellular space over variable distances. Within the obliterated zone, the dense outer leaflets of the adjoining cell membranes converge to form a single intermediate line. A diffuse band of dense cytoplasmic material is often associated with this junction, but its development varies from one epithelium to another. The zonula adhaerens (intermediate junction) is characterized by the presence of an intercellular space (~200 A) occupied by homogeneous, apparently amorphous material of low density; by strict parallelism of the adjoining cell membranes over distances of 0.2 to 0.5 µ; and by conspicuous bands of dense material located in the subjacent cytoplasmic matrix. The desmosome or macula adhaerens is also characterized by the presence of an intercellular space (~240 A) which, in this case, contains a central disc of dense material; by discrete cytoplasmic plaques disposed parallel to the inner leaflet of each cell membrane; and by the presence of bundles of cytoplasmic fibrils converging on the plaques. The zonula occludens appears to form a continuous belt-like attachment, whereas the desmosome is a discontinuous, button-like structure. The zomula adhaerens is continuous in most epithelia but discontinuous in some. Observations made during experimental hemoglobinuria in rats showed that the hemoglobin, which undergoes enough concentration in the nephron lumina to act as an electron-opaque mass tracer, does not penetrate the intercellular spaces beyond the zonula occludens. Similar observations were made in pancreatic acini and ducts where discharged zymogen served as a mass tracer. Hence the tight junction is impervious to concentrated protein solutions and appears to function as a diffusion barrier or "seal." The desmosome and probably also the zonula adhaerens may represent intercellular attachment devices.     

Reduced Diversity and High Sponge Abundance on a Sedimented Indo-Pacific Reef System: Implications for Future Changes in Environmental Quality

Although coral reef health across the globe is declining as a result of anthropogenic impacts, relatively little is known of how environmental variability influences reef organisms other than corals and fish. Sponges are an important component of coral reef fauna that perform many important functional roles and changes in their abundance and diversity as a result of environmental change has the potential to affect overall reef ecosystem functioning. In this study, we examined patterns of sponge biodiversity and abundance across a range of environments to assess the potential key drivers of differences in benthic community structure. We found that sponge assemblages were significantly different across the study sites, but were dominated by one species Lamellodysidea herbacea (42% of all sponges patches recorded) and that the differential rate of sediment deposition was the most important variable driving differences in abundance patterns. Lamellodysidea herbacea abundance was positively associated with sedimentation rates, while total sponge abundance excluding Lamellodysidea herbacea was negatively associated with rates of sedimentation. Overall variation in sponge assemblage composition was correlated with a number of variables although each variable explained only a small amount of the overall variation. Although sponge abundance remained similar across environments, diversity was negatively affected by sedimentation, with the most sedimented sites being dominated by a single sponge species. Our study shows how some sponge species are able to tolerate high levels of sediment and that any transition of coral reefs to more sedimented states may result in a shift to a low diversity sponge dominated system, which is likely to have subsequent effects on ecosystem functioning.     

Protein LUMA is a cytoplasmic plaque constituent of various epithelial adherens junctions and composite junctions of myocardial intercalated disks: a unifying finding for cell biology and cardiology

In a series of recent reports, mutations in the gene encoding a protein called LUMA (or TMEM43), widely speculated to be a tetraspan transmembrane protein of the nuclear envelope, have been associated with a specific subtype of cardiomyopathy (arrhythmogenic cardiomyopathies) and cases of sudden death. However, using antibodies of high specificity in immunolocalization experiments, we have discovered that, in mammals, LUMA is a component of zonula adhaerens and punctum adhaerens plaques of diverse epithelia and epithelial cell cultures and is also located in (or in some species associated with) the plaques of composite junctions (CJs) in myocardiac intercalated disks (IDs). In CJs, LUMA often colocalizes with several other CJ marker proteins. In all these cells, LUMA has not been detected in the nuclear envelope. Surprisingly, under certain conditions, similar CJ localizations have also been seen with some antibodies commercially available for some time. The identification of LUMA as a plaque component of myocardiac CJs leads to reconsiderations of the molecular composition and architecture, the development, the functions, and the pathogenic states of CJs and IDs. These findings now also allow the general conclusion that LUMA has to be added to the list of mutations of cardiomyocyte junction proteins that may be involved in cardiomyopathies.     

Contact inhibition of locomotion and the structure of homotypic and heterotypic intercellular contacts in embryonic epithelial cultures

Epithelia from the early chick embryo have been grown in culture and then fixed for electron microscopy so that the ultrastructure of intercellular contacts could be examined. Epithelia were used which showed various forms of contact inhibition of locomotion upon confrontation with one another. Confrontations of hypoblast with hypoblast after 6 days, and endoblast with endoblast after 24 h showed type 1 contact inhibition and formed desmosomes and zonulae adhaerentes with extensive microfilament collinearity between apposed cells. Hypoblast-hypoblast confrontations after 24 h resulted in type 2 contact inhibition with considerable ruffling and position shifting. In this case desmosomes were absent and microfilament collinearity was restricted. Endoblast cells after 24 h in culture show type 2 inhibition with respect to hypoblast monolayers which they infiltrated upon confrontation. Examination of these heterotypic contacts also showed an absence of desmosomes and reduced adhaerens junctions. Intermediate filaments accumulated at all contact sites examined. It is concluded that whereas type 1 contact inhibition of locomotion in these epithelial cells is accompanied by desmosome formation and extensive zonula adhaerens junctions, type 2 inhibition is not. These junctional deficiences may be responsible in part for the cell motility characteristically observed in monolayers of type 2 inhibited cells.     

The Early Metazoan Trichoplax adhaerens Possesses a Functional O-GlcNAc System

Protein O-GlcNAcylation is a reversible post-translational signaling modification of nucleocytoplasmic proteins that is essential for embryonic development in bilateria. In a search for a reductionist model to study O-GlcNAc signaling, we discovered the presence of functional O-GlcNAc transferase (OGT), O-GlcNAcase (OGA), and nucleocytoplasmic protein O-GlcNAcylation in the most basal extant animal, the placozoan Trichoplax adhaerens. We show via enzymatic characterization of Trichoplax OGT/OGA and genetic rescue experiments in Drosophila melanogaster that these proteins possess activities/functions similar to their bilaterian counterparts. The acquisition of O-GlcNAc signaling by metazoa may have facilitated the rapid and complex signaling mechanisms required for the evolution of multicellular organisms.     

Ear morphology of the frog-eating bat (Trachops cirrhosus,family: Phyllostomidae): Apparent specializations for low-freqency hearing

The frog-eating bat (Trachops cirrhosus) is unusual among bats studied because of its reliance on low-frequency (<5 kHz) sounds emitted by frogs for prey localization. We investigated the ear of this bat in order to identify anatomical features that might serve as adaptations for low-frequency hearing. Trachops cirrhosus has a variety of anatomical features that might enhance low-frequency hearing, either by increasing sensitivity to low-frequency sounds or expanding the total frequency range to include lower frequencies. These bats have long pinnae, and a long and wide basilar membrane. The basal portion of the basilar membrane is much stiffer than the apical portion, and the basal portion of the tectorial membrane is more massive than the apical portion. There is also a concentration of mass in the apical portion of the cochlea. T. cirrhosus possesses the largest number of cochlear neurons reported for any mammal, the second highest density of cochlear neurons innervation known among mammals, and three peaks of cochlear neuron density. Other bats have two peaks of cochlear neuron density, lacking the apical concentration, while other mammals usually have only one. T. cirrhosus differs from most other small mammals and bats in characteristics of the apical portion of the cochlea, i.e., that area where the place theory of hearing predicts that low frequencies are detected.