Radial Canals Research Articles

The Functional Morphology of Starfish Tube Feet: The Role of a Crossed-Fiber Helical Array in Movement.

The morphology and mechanics of the tube feet, ampullae, and lateral and radial canals of the water vascular systems of Luidia clathrata and Astropecten articulatus (Echinodermata, Asteroidea) were analyzed. Histological methods, based on embedding in both paraffin and glycol methacrylate, were used to document the arrangement of muscle and connective tissue. The tube foot wall includes longitudinal muscles and connective tissue fibers, the latter arranged in a crossed-fiber helical array, with a fiber angle of about 67{deg} in elongated tube feet. No evidence was found for the circular rings of connective tissue reported in earlier studies; the appearance of rings is probably an artifact of folding. The ampullae are bilobed and include circumferentially arranged muscle fibers and connective tissue fibers aligned 90{deg} to the muscle. The lateral canals are short and equipped with oneway flap valves similar to those described for other echinoderms. The radial canal is thin-walled, nonmuscular, and enclosed in the connective tissue and ossicles of the ambulacrum. Frame-by-frame video analysis of both intact animals and animals with "windows" cut in the arm wall was used to document the movements of the tube feet and ampullae. No evidence was found for the previously suggested role of the radial canal in protracting the tube feet. The ampullae protract the tube feet and antagonize the tube foot musculature. The fiber angle of the connective tissue allows protraction and prevents dilation of the tube feet, and limits elongation of the ampullae.

Systematic Wood Anatomy of the Genus Tapirira Aublet (Anacardiaceae)-a Numerical Approach

A wood anatomical study of the Mexican species ofTapirira was undertaken to uncover evidence to help clarify the systematics of the genus. Three to five individuals of each of 10 populations from throughout the range of the genus in Mexico were studied. For comparative purposes, three Central and South American species were also examined. Cluster analysis showed that the genus in Mexico can be separated into two phenetic units, represented byT. mexicana, a species widely distributed in Mexico, andT. chimalapana, a species endemic to the Isthmus of Tehuantepec. Canonical discriminant and factor analyses indicate that the quantitative wood characters most useful in distinguishing these species are wall thickness of fibers and vessels, diameter of fiber lumen, and diameter and frequency of radial canals. These species also differ in presence/absence of tannins in the fibers and color and specific gravity of the wood. The South American species,Tapirira bethanniana, T. guianensis, andT. obtusa, have wood anatomy similar to that ofT. chimalapana. The differences in the wood anatomical characters betweenT. mexicana and the other taxa suggest that the infrageneric classification ofTapirira should be reevaluated. The results of this study support the utility of sampling of populations in comparative wood anatomy.

Monoclonal antibody to a bacterial endonuclear symbiont Holospora cross reacts with proteins of contractile vacuole radial canals of Paramecium species.

A monoclonal antibody (mAb) IR-2-1 was raised against a 67-kDa protein purified from the macronucleus-specific bacterial symbiont Holospora obtusa of Paramecium caudatum. The mAb was found to react with two bands (31 and 67-kDa) on gels of H. obtusa. Indirect immunofluorescence microscopy showed that these antigens were distributed inside the cells. However, unexpectedly, this mAb also cross reacted with the radial arms of the contractile vacuole in P. caudatum, P. tetraurelia, P. multimicronucleatum, P. jenningsi and P. bursaria as well as with their cytoplasm. Immunoelectron microscopy showed that the antigens were located on the decorated spongiome of the radial arms. In immunoblots, mAb IR-2-1 reacted with a band of 67 kDa in all Paramecium species examined. However, no band appeared in the immunoblot of isolated macronuclei of H. obtusa-free P. caudatum and no label was seen in the nuclear matrix of the macronucleus of air-dried P. caudatum. These results suggest that the 67-kDa antigen found in H. obtusa was not imported from the host macronucleus and the same antigen in the host contractile vacuoles and cytoplasm were not derived from the symbiont. These results also showed that an epitope on the decorated spongiome of the Paramecium species is shared by its bacterial symbiont. In contrast to the decorated tubule-specific mAb, DS-1, the antigens for IR-2-1 appeared to be loosely membrane bound as they were lost in paraformaldehyde fixed and acetone permeabilized Paramecium.

Gigaspora gigantea: parasitism of spores by fungi and actinomycetes

Fungi and actinomycetes were isolated monthly for one year from spores of the arbuscular mycorrhizal fungus Gigaspora gigantea recovered from a maritime sand dune. Spores in four different stages of vigour (newly formed, greenish-yellow healthy; yellow, moribund, mottled with brown spots; brown; and dead, blackened and collapsed) were used for isolation. From 272 isolates cultured from crushed, surface-disinfected G. gigantea spores, 44 species of fungi and six actinomycete species were recovered. The five most frequently isolated organisms were Acremonium sp., Chrysosporium parvum, Exophiala werneckii, Trichoderma sp. and Verticillium sp. The species lists derived from the four spore types differed significantly. Thirty-one of the isolated species were tested for their ability to parasitise healthy G. gigantea spores and to invade spores killed by a hot water treatment. Twenty-two species could function as pathogens, forming internal projections (IP), fine radial canals (FRC) or both in the spore wall. IP were induced by Acremonium sp., Chrysosporium parvum, Cladosporium sp., Geomyces pannorum, Oidiodendron sp., Sporothrix sp., Verticillium sp. and by the actinomycetes Nocardia sp. and Streptomyces sp. The IP length was positively correlated with duration of exposure to the parasites. In the bioassay, both IP and FRC were formed by live spores, while heat-killed spores possessed only FRC after penetration by the test microorganisms. Pathogenicity differed among the parasites and was greatest for Verticillium and Acremonium .

Structure and origin of the tooth pedicel (the so-called bone of attachment) and dental-ridge bone in the mandibles of the sea breams Acanthopagrus australis, Pagrus auratus and Rhabdosargus sarba (Sparidae, Perciformes, Teleostei).

Scanning electron and light microscopy were used to show that the pedicels of fish teeth (the so-called "bones of attachment") consist of three types of dentine that lie concentrically around a pulp cavity lined with typical odontoblasts with cytoplasmic processes in dentinal tubules. Circumpulpal canalar dentine forms on a thin layer of orthodentine that is encased in mantle dentine. Canalar dentine is a new name given to a dentine that is similar to vasodentine in canal arrangement, but not apparently in canal content. An inner series of wide, radial canals and an outer series of highly-branched thin canals of two diameters are inhabited by a population of cells, the osteodentocytes, and collagen fibril bundles. The flat, oval osteodentocytes appear to be quiescent cells, lying on the sides of the tubules and covered by a sheath. Plump, intensely metachromatic osteodentocytes appear to be more synthetically active. The canals and the osteodentocytes originate from blood capillaries enclosed in the predentine during dentinogenesis. New teeth begin within the small cavities present in spongy bone that were enlarged by multinucleated osteoclasts during tooth growth. Pedicel formation is initiated by the extension of the crown mantle dentine, forming the outer layer of the crimped ligament and outlining the future length and curvature of the pedicel. Central and inner ligament zones are subsequently formed as orthodentine is secreted in both crown and pedicel, and canalar dentine in the pedicel. Spongy bone osteogenesis begins during stage 1 of pedicel formation with the aggregation of osteoblasts and blood capillaries in the bone cavities and in the dermis between the pedicels. Loose fibrillar osteoid condenses into incomplete thin trabeculae bordered by intensely metachromatic osteoblasts. Osteoblasts become enclosed in the developing trabeculae that thicken to give mature spongy bone with osteocytes throughout. We conclude that the pedicels are the true bases of teeth, that the dental ridge is formed from pedicels and spongy bone, and that sea bream spongy bone is cellular. The term "bone of attachment" is inappropriate for the pedicel. It can be used for the spongy bone between the compact bone of the jaw and between adjacent pedicel.

A Plain Man's Guide to Rudist Bivalves

The rudists are a group of aberrant bivalve molluscs known from the Upper Jurassic to end Cretaceous of the Tethyan region. Although paleobiologically fascinating, rudists are seldom discussed in detail in textbooks. This paper explains the principal features of rudist morphology and paleobiology. Recent significant advances in rudist research include the interpretation of mantle feeding in radiolitids, associated with limited shell gaping and reduced mantle cavity volume; feeding associated with radial canals in the free valves of hippuritids; recognition of the migration of rudists across broad oceans by island-hopping of larvae; a suggestion that rudists may not have been constructors of reefs; and the refinement of patterns of evolution and extinction.

PERIDIAL DEVELOPMENT IN GLOMUS MOSSEAE (GLOMACEAE)

Unispored sporocarps of a Kansas isolate of G. mosseae at all stages of development were prepared for light and scanning electron microscopy to reveal the process involved in peridium formation and spore release. Five stages were identified: 1) peridial hyphal branch origination from below the sporophore attachment; 2) continued peridial hyphal branching and weft formation; 3) adherence of peridial hyphae to the spore wall and completion of peridial expansion into mature state; 4) separation of the primary (evanescent) spore wall layer from the spore and the inner peridial layer; and 5) release of the de‐peridiate spore. Spores in stage 3 were surrounded by a two‐layered peridium consisting of thinner‐walled, parallel‐arranged hyphae next to the spore and thicker‐walled, jigsaw puzzle‐arranged hyphae to the outside; the latter of which collapsed during stages 4 and 5. Fine radial canals and lignituberlike ingrowths were seen in both the de‐peridiate spore wall and, for the first time, in the shed peridium. Comparison of these results with studies of related sporocarpic genera lead to the conclusion that the process of peridium formation in G. mosseae is similar to that of G. coronatum, but that other sporocarpic Glomus representatives must be characterized before valid comparisons may be drawn.

A revision of the sub-family Nectopyramidinae (Siphonophora, Prayidae)

The sub-family Nectopyramidinae (Siphonophora, Prayidae) is reviewed and revised. Previously the sub-family was considered to comprise one genus, Nectopyramis with four species. However, it is shown that the two types of nectophore previously ascribed to N. spinosa are actually the larval nectophores of two other species, namely N. thetis and N. natans . A new genus Nectadamas gen. nov. is erected to include the other species, diomedeae . The differences between the two genera are principally the arrangement of the radial canals to the nectosac and the shape of the hydroecium in the definitive nectophore; and the presence or absence of a special nectophore. A new species Nectadamas richardi sp. nov. is described, the eudoxid of which previously had been ascribed to N. spinosa .

Affinities and class-level systematics of the phylum Cnidaria

Phylogenetic relationships among the cnidarian classes Anthozoa, Hydrozoa and Scyphozoa, and between Cnidaria and other metazoan phyla, continue to be subject to widely divergent interpretations. Also controversial are the affinities of numerous fossil groups, including Byronia Bischoff, Sphenothallus Hall and conulariids, that have been interpreted as extinct cnidarians. Currently favored interpretations of evolution within Cnidaria are generally consistent with one of two alternative hypotheses of phylogenetic relationships: scyphozoans and anthozoans are members of a monophylclic group that excludes hydrozoans; or scyphozoans and hydrozoans are members of a monophyletic group that excludes anthozoans. Putative anthozoan-scyphozoan synapomorphies include (1) gastric septa present; (2) cnidae present in both ectoderm and gastroderm; (3) sex cells gastrodermal; and (4) mesoglea contains amoeboid cells. Putative hydrozoan-scyphozoan synapomorphies include (1) medusa present; (2) tetraradial symmetry; (3) rhopaloid nematocysts; and (4) similarities in sperm structure.Evaluation of alternative hypotheses of relationships within Cnidaria is complicated by uncertainty surrounding relationships between this and other metazoan phyla. While some investigators have interpreted Cnidaria and Ctenophora as members of a monophyletic group that excludes other phyla, others have argued that ctenophorans are more closely related to platyhelminths than they are to cnidarians. Putative cnidarian-ctenophoran synapomorphies include (1) production of cells modified for prey capture; and (2) presence of a medusa. Putative ctenophoran-platyhelminth synapomorphies include (1) presence of gonoducts; (2) ciliated cells with several to many cilia; (3) determinate cleavage; and (4) muscle cells developed from mesoderm. Comparisons of these and other phyla indicate that the strongest hypotheses of synapomorphy are those between cnidarians and ctenophorans. Ctenophorans do not have a mesoderm, and they lack complex reproductive structures that can be homologized with platyhelminth gonoducts. Similarities between ctenophorans and platyhelminths in ciliation and cleavage type are either non-homologous or shared primitive. The most recent common ancestor of ctenophorans and cnidarians was probably a medusa-like animal with circular and meridional muscle fibers and a non-septate digestive cavity having four radial canals. This cavity probably lacked cells specialized for prey capture, but glutinant prey-capture structures may have been present on tentacles. Sperm produced by this common ancestor were most similar to sperm of extant ctenophorans, hydrozoans and scyphozoans. Anatomical features unique to ctenophorans or cnidarians, regarded by some investigators as evidence against a close relationship between these two groups, are autapomorphies. These interpretations imply that putative hydrozoan-scyphozoan synapomorphies are actually shared primitive, and that the presence of gastric septa and cnidae-bearing gastric filaments in scyphozoans and anthozoans is shared derived. This would mean that the most parsimonious hypothesis of phylogenetic relationships within Cnidaria is that anthozoans and scyphozoans are members of a monophyletic group that excludes hydrozoans.Debate over relationships among these extant taxa has heightened interest in the affinities of prominent groups of problematic fossil cnidarians. Byronia Bischoff, Sphenothallus Hall and conulariids, all characterized by an apatitic, multilamellar theca, show detailed anatomical similarities to hydrozoans and/or scyphozoans. Putative synapomorphies linking Byronia and coronatid scyphozoans include the presence of multiple whorls of thorn-like nodes projecting into the thecal cavity, with each whorl consisting of eight nodes arranged in two sets of four nodes each. Sphenothallus, characterized by a pair of tentacles and, in some species, multiple branching, is most similar to hydrozoan and scyphozoan polyps, many of which are colonial or exhibit a single pair of tentacles early in their development. Similarities in hard- and soft-part anatomy between scyphozoans and conulariids suggest that conulariids, like scyphozoans, possessed four gastric septa and produced medusae through polydisc strobilation. Although conulariids have been interpreted as ancestral to extant cnidarians, they are more likely either a sister group to Scyphozoa or members of this class.

Medusae from Mcmurdo Sound, Ross Sea including the descriptions of two new species, Leuckartiara brownei and Benthocodon hyalinus

Seven species of medusae were collected using scuba equipment in neritic waters of McMurdo Sound, Ross Sea, Antarctica. Two species dominated, the narcomedusa Solmundella bitentaculata and the scyphomedusa Diplulmaris antarctica. Two new taxa were found. Leuckartiara brownei n. sp., a pandeid anthomedusa, has gonads with two major longitudinal folds in the interradii and several smaller perradially directed folds. Besides four large perradial tentacles, it has up to 28 short “rudimentary” tentacles. This is the first report of this genus from the Southern Ocean. Benthocodon hyalinus n. gen., n. sp., a rhopalonematoid trachymedusa, has 8 linear to sinuous gonads on the radial canals. The tubular manubrium is attached to a gastric peduncle. The tentacles are numerous (about 800) and grow successively. This is the second reported trachymedusa from the Ross Sea. Solmundella bitentaculata ate the thecosome pteropod Limacina helicina. Diplulmaris antarctica medusae fed on the gymnosome pteropod Clione antarctica and on L. helicina. The hyperiid amphipod Hyperiella dilatata, mostly females, was seen attached to the exumbrellas of both D. antarctica and S. bitentaculata. Up to 54 amphipods were seen on each D. antarctica medusa. The amphipods did no visible damage to the medusae.

Surface topography analysis of the ryanodine receptor/junctional channel complex based on proteolysis sensitivity mapping.

The ryanodine receptor/junctional channel complex (JCC) has been isolated and identified morphologically as the foot structure spanning the gap between sarcoplasmic reticulum and the transverse tubule. Functionally, the JCC contains the calcium release channel which mediates calcium release in excitation-contraction coupling in skeletal muscle. The three-dimensional structure of the JCC, obtained by image analyses of electron micrographs, reveals two distinct faces and an efflux pathway indicated by a central pore with a diameter of approximately 20 A and four radial canals leading to the myoplasm. The JCC consists of four identical protomers, with Mr = 565,233 each. In the present study, proteolytic digestion of native JCC was carried out to obtain insight into its surface topography. Peptides generated by cleavages with endoproteinases Lys-C and Glu-C were separated by reverse-phase high pressure liquid chromatography and sequenced. Twenty-four cleavage sites have been identified and are equated to surface exposed peptides. Surface probability analysis, combined with protease sensitivity, has been used to provide independent information identifying sequences with high likelihood of appearing on the surface. This analysis also predicts sequences with low surface probability which may be buried within the hydrophobic core of the structure. Furthermore, regions of high surface probability, not cleaved by proteases, are potential candidates for surface-surface association and/or the hydrophilic internal calcium efflux pathway.

Monoclonal antibody study of the decorated spongiome of contractile vacuole complexes of Paramecium

A monoclonal antibody (mAb) has been developed and selected by immunofluorescence for the radial canals of the contractile vacuole complex (CVC) of Paramecium multimicronucleatum. By applying indirect immunogold labeling to thin frozen sections this mAb has been shown at the electron microscopic level to be specific for the decorated spongiome. We have used the mAb to study the normal interfission appearance as well as developmental stages of the decorated spongiomes. Two decorated spongiomes, presumably involved in water sequestration, radiate as 5-10 bands from unlabeled, circular, 25 microns diameter centers. Two new CVCs arise just anterior to the space occupied by the old spongiomes, the new anterior CVC appearing slightly before the posterior one. Development of the new spongiomes around a 10 microns unlabeled central zone is accompanied by a regression of old spongiome bands until the lengths of these bands in both old and new CVCs are equal just before cell division. After division both old and new spongiome bands grow at equal rates to the same length. Exceptions to the above general scheme, both in number of CVCs in interfission, as well as in position of the new relative to the old CVCs, are also observed.

Effects of Forskolin on Fine Structures of Medaka Follicles: (forskolin/medaka follicle/cell organelle/cell junction/oocyte maturation).

Effects of forskolin (FK), which stimulates production of 17α, 20β-dihydroxy-4-pregnen-3-one and estradiol-17β, on the fine structure of preovulatory follicles of Oryzias latipes were examined. Granulosa cells incubated in culture medium containing FK exhibited dislocation of the nucleus from the chorion side to the basement membrane side, vesiculation of conspicuous dilated endoplasmic reticulum (ER) with electron-dense material and Golgi lamellae, and development of large oval mitochondria with an electron-dense matrix. Moreover, a thin vesicular layer adherent to the outermost layer of the chorion was found in all immature oocytes at the end of incubation in the presence of FK. Intercellular junctions between granulosa cells and the oocyte gradually decreased during incubation in the presence of FK, and were finally lost with closure of the radial canals in the chorion at the end of the incubation. On the other hand, intrafollicular oocytes that were first incubated with FK for 10 hr, matured normally when they were incubated an additional 8 hr in plain medium. In granulosa cells of these follicles, the dilated ER and vacuolated Golgi lamellae were no longer detectable. These observations suggest that the development of dilated ER and vacuolated Golgi lamellae is characteristic of granulosa cells induced by FK.

Source and Fate of Lipids in Polar Gelatinous Zooplankton

The presence or absence of accumulated lipids in arctic and Antarctic medusae and ctenophores was determined by visual examination of living specimens with a dissecting microscope. Lipid accumulations were obvious because of their high refractive indices. Lipids were seen in many of the 200+ gelatinous zooplankton specimens collected. They always consisted of various-sized droplets and larger masses within the lumen of the gastrovascular system. No true depot lipids or adipose tissue were present. The accumulation of lipids was observed in feeding animals, suggesting that the prey-derived lipids were unmodified. Disappearance of lipids in starved animals suggested that lipids are taken up and assimilated. In medusae, they occurred in the stomach, ring and/or radial canals. In most ctenophores, lipids were found in the meridional canals below the comb rows. However, in one ctenophore species, Mertensia ovum , lipids are stored in special sacs associated with the tentacle bulbs. Lipids were more frequently observed in arctic than in Antarctic gelatinous zooplankton. A review of the literature suggests that in the Antarctic, the average lipid content of gelatinous predators is about 3% DW (range = 0.4-6%), whereas in the Arctic it is nearly three times higher, about 8% DW (range = 1.5-22%). These differences are probably related to the amounts of lipids in their prey. The abundance of lipid-rich Calanus spp. copepods in the Arctic may be responsible for the high levels of lipids in gelatinous predators. Key words: lipids, gelatinous zooplankton, ctenophores, medusae, Arctic, Antarctic, polar, feeding, starvation

Quelques considérations sur les genres Tyrrhenocythere (Ruggieri, 1955)et Hemicytheria (Pokornyi, 1955) (Ostracoda, Crustacea) du Néogène supérieur de la Paratéthys

We found one Tyrrhenocythere species ( T. incerta Olteanu, 1988 ) from the Upper Dacian, which is similar to a Hemicytheria species ( H. maeotica Olteanu, 1988 ) from the Upper Meotian (Dacic Basin) as regards the external morphology. Within a Tyrrhenocythere population (very unitary with respect to the external morphology of the valves) we found several specimens with radial pore canals of Hemicytheria type. We noticed that during the ontogenetic evolution of all the Tyrrhenocythere species, only the two larval stages present radial pore canals concentrated in fascicles. The younger juveniles have radial, simple, straight and rarely bifurcated canals, like the Hemicytheria valves. The number of these canals as well as the fascicles increasestowards the maturity of the individual. At the Tyrrhenocythere fresh-water species the number of fascicles (and implicity of the radial pore canals) differs even within the same population. The stability of the number of fascicles appears directly proportional to the salinity increase. The two groups of individuals, with radial pore canals of Tyrrhenocythereand respectively Hemicytheria types are separated only by the structure and number of the radial canals, the other morphological features being identical. In fact, Tyrrhenocythere is a Hemicytheria with radial porecanals concentrated in fascicles. We consider this organisation of the radial canals as a qualitativeleap, a specific adaptation, necessary in a certain ecological context. Under certain conditions of ecological instability — the case of the Kouialnikian — the ontogenetic evolution of some individuals within this population is very likely to have stopped before maturity preserving the simple radial pore canals as an undeveloped, primitive, but necessary character.

Prepalintomic metamorphosis in Hyalophysa chattoni (ciliophora, apostomatida): Cytoplasmic ultrastructure

The transformation of cytoplasmic structures during prepalintomic development in the apostome ciliate Hyalophysa chattoni was studied by transmission electron microscopy. The trophont's food mass was divided into large sectors in the swimming stages (I, II), into globular masses in the cystic stages III, IV, and finally into typical oblate pellets in stage V. The oral fiber was observed in stages I-III and the rosette was observed in stages I, II and reappeared after division (stage VI), indicating that resorption occurred in stages IV and V; however, no signs of resorption were observed in either organelle. Mitochondria showed great variability in shape in stage II. Trichocysts increased abruptly in numbers in stage III and early stage IV. The water expulsion system of this species was found to possess ampullae, radial canals, and a smooth tubular spongiome in addition to the contractile vacuole.

The architecture of the canal systems of Petrosia ficiformis and Chondrosia reniformis studied by corrosion casts (Porifera, Demospongiae)

The three-dimensional organization of the canal system in two sponge species, Petrosia ficiformis and Chondrosia reniformis, was studied using corrosion casts. Casts were made of live animals, in situ, and canal replicas were analzyed by scanning electron microscopy (SEM). In P. ficiformis the incurrent system consists of a superficial canal network giving rise to large radial canals, which ramify and anastomosize forming an internal web. Excurrent canals are arranged into modular ramified systems radiating from atrial cavities opening to the exterior. Main excurrent canals run at various depths within the sponge, even through the superficial incurrent network. Both incurrent and excurrent canal replicas show smooth, blind-ending capillaries. Some large incurrent canals merge with excurrent ones, thus bypassing choanocyte chambers. In C. reniformis there is a cortical collagen layer crossed by three-like incurrent canals, the “twigs” of which communicate with groups of inhalant pores. The stems of tree-like canals penetrate into the sponge medulla where they ramify and anastomosize to form a web. Main excurrent canals arise from large cloacal ducts leading to the oscular openings. They give rise to a sequence of branches intersecting the incurrent web. Both incurrent and excurrent canals have sharp, blind-ending capillaries. Morphometric data functions show that diameter scaling in canal branches is exponential in Petrosia and linear in Chondrosia. Structural differences and homologies between the two species are discussed.

Filamentous actin in Paramecium cells: mapping by phalloidin affinity labeling in vivo and in vitro.

In living Paramecium cells, microinjected rhodaminyl (R)-phalloidin rapidly labels a thin cortical layer. This can be more clearly resolved with microinjected and fixed cells (allowing for better resolution) as well as with isolated pellicles (surface membrane complexes with trichocysts, microfilaments, and mitochondria attached). Labeling of a longitudinal and perpendicular pattern, reflecting the relief of the cell surface, and labeling of ciliary basal bodies then becomes clearly visible. Other structures labeled by R-phalloidin are the surfaces of food vacuoles of different sizes and, although inconsistently, the borders of the buccal cavity. Small acidic compartments (as identified by acridine orange fluorescence vital staining), probably representing acidosomes and small lysosomes, were not labeled. F-actin on food vacuole surfaces may somehow be involved in intracellular transport or fusion processes. No labeling was observed in association with the osmoregulatory system (contractile vacuoles and their ampullae and radial canals). The specificity of in vivo labeling obtained was supported by the abolition of R-phalloidin labeling when isolated pellicles were pretreated with unlabeled phalloidin or with DNAse I. It was also possible to discriminate among different layers of R-phalloidin binding in the cortex by detaching different layers of the surface complex from each other. Since localization of F-actin in ciliates has raised a considerable amount of dispute in the past, we also repeated all these experiments with RITC-labeled HMM, but we obtained essentially the same labeling pattern as with R-phalloidin. Ciliary basal bodies therefore clearly contain some F-actin. Our data shed some light on aspects of surface structuring and motility in these cells.

Coalescing units for separating three-phase mixtures

Phase separators are widely used in gas fields and gas processing factories for separating three-phase mixtures of petroleum (or natural) gas, hydrocarbon condensate, and diethylene-glycol. Work has been carried out to improve the coalescing units and to create the technology of producing them. As a result of this work, a coalescing unit was developed which consists of a coil of glass mats, and this significantly reduces the amount of labor necessary to produce it. This paper examines units made up by assembling a number of polymer rings with radial and circumferential canals into a framework. Studies on the glass mat coalescing unit indicated that this material is stable towards the effects of hydrocarbon condensate and diethyleneglycol. Results show that polymer rings have adequate mechanical strength and that it is possible to use them under suitable conditions.

Communications of Oocyte-Granulosa Cells in the Chum Salmon Ovary Detected by Transmission Electron Microscopy: (oocyte/granulosa cell/intercellular junction/salmonid ovary/teleost).

The communications between oocytes and granulosa cells in the ovary of the chum salmon, Oncorhynchus keta, were examined in follicles in which the oocytes were at the stage of germinal vesicle migration. Microvilli were seen extending through the radial canals of the egg envelope and terminating in either the subfollicular space or at the surface of granulosa cells. Cytoplasmic processes extending from granulosa cells toward oocytes were also observed; most of the processes appeared to end in the radial canals, but some passed through the canals and terminated as bulbs in slight depressions or indentations of the oolemma. Various types of junctional structures that participated in intimate association between these cells were seen. The granulosa cells were found to be firmly fixed on the surface of the intrafollicular oocyte by means of desmosomes or desmosome-like junctions. It is speculated that intrafollicular oocytes communicate with surrounding granulosa cells directly through gap junctions and indirectly by endocytosis of material released from the granulosa cells.