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  • 1
    Electronic Resource
    Electronic Resource
    Larval morphology of the Nemertean Carcinonemertes epialti (Nemertea: Hoplonemertea) (1981)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 169 (1981), S. 61-70 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphology of the newly hatched larva of Carcinonemertes epialti Coe has been examined by light and electron microscopy. The newly hatched larva is covered with cilia and measures about 110 μm in length. Four types of epidermal cells are recognizable: (1) Multiciliated cells, (2) vacuolated cells, (3) mucous cells, and (4) “knob cells”. The knob cells protrude from the posterior end of the larva and contain granules and bundles of microfilaments. The gut is incomplete and is located ventral to the bipartite proboscis. A bilobed brain and two subepidermal ocelli are found in the anterior end of the larva. The anterior and posterior cirri are composed of long, tightly appressed cilia that arise from an invagination of the epidermis at each end of the larva. The anterior cirrus is surrounded by two types of glandular cells. It is proposed that the knob cells have a role in larval attachment, combining the functions of the adhesive cells and anchor cells described in the duo-gland system of turbellarians. The cirri are believed to be larval sensory structures that function in substrate selection. Histological and ultrastructural observations suggest that the larvae of Carcinonemertes are relatively long lived and develop into juveniles without a drastic metamorphosis.
    Additional Material: 23 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051690106
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  • 2
    Electronic Resource
    Electronic Resource
    S.E.M. and polarization microscopy of nemertean stylets (1983)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 175 (1983), S. 153-169 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the stylets produced by nine species of nemerteans has been examined by scanning electron microscopy (S.E.M.) and polarized light microscopy. Stylets are solid, nail-shaped structures that typically reach lengths of 50-200 μm. Each stylet is composed of a centrally located organic matrix surrounded by an inorganic cortex that contains calcium and phosphorus. When viewed at high magnifications, fine granules can be seen throughout the organic matrix, and the cortex appears to be composed of densely packed homo-geneous material. Fractured specimens and whole matrices isolated from decalcified stylets reveal a close correspondence between the shape of the organic matrix and that of the surrounding cortex. This similarity in morphology suggests that the organic matrix serves as a template during calcification of the stylet. The fact that abundant material can be seen in the core of incinerated stylets, and in the central region of stylets that had been soaked for several hours in sodium hypochlorite, supports the hypothesis that the organic matrix is also highly calcified. Polarization microscopy of nemertean stylets indicates that they are composed of a crystalline, rather than amorphous, form of calcium phosphate. The probable organization of the calcium phosphate crystals is discussed.
    Additional Material: 35 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051750205
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  • 3
    Electronic Resource
    Electronic Resource
    The fine structure and development of calcified skeletal elements in the body wall of holothurian echinoderms (1986)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 188 (1986), S. 273-288 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The calcareous ossicles and iron-rich calcified granules in the integument of sea cucumbers (Echinodermata: Holothuroida) have been examined by light and electron microscopy. Most ossicles are perforated, platelike structures that measure 100-500 μm long and consist of magnesium-rich calcite. The formation of ossicles occurs within multinucleated syncytia of sclerocytes that are situated in the dermal layer of the body wall. Sclerocytes possess fairly large numbers of mitochondria and are characteristically enveloped by an external lamina. Each ossicle arises as a minute rodlike spicule that branches and develops into a fenestrated skeletal element. When viewed by SEM, fully developed ossicles appear non-crystalline. Following decoration with synthetically grown calcite seeds, however, each ossicle reveals an ordered array of crystallites that seem to be aligned perpendicular to the ossicle's original plane of growth. Examinations of sectioned ossicles indicate that the mineral phase in each skeletal element lacks a well developed matrix of EDTA-insoluble organic substances. Ossicles first arise in the ciliated, lecithotrophic larvae of Eupentacta quinquesimita at about 1 week postfertilization. Two-week-old specimens adopt an epibenthic existence and subsequently become enveloped by imbricated ossicles that are secreted by sclerocytes resembling those found in adults. In molpadiid holothurians, the adult body wall contains numerous reddish-brown granules that are chiefly composed of iron-rich subunits. The dermal granules differ from calcitic ossicles in developing extracellularly in association with finely filamentous material.
    Additional Material: 30 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051880303
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  • 4
    Electronic Resource
    Electronic Resource
    Styletogenesis in nemertean worms: The ultrastructure of organelles involved in intracellular calcification (1984)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 179 (1984), S. 119-134 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of cellular organelles involved in stylet formation is examined in six species of nemertean worms by transmission electron microscopy (TEM). Stylets are nail-shaped structures containing calcium phosphate that are assembled intracellularly in large uninucleate cells, called styletocytes. Each stylet develops within a membrane-bound vacuole in the styletocyte cytoplasm. Well developed arrays of Golgi bodies are typically found in the vicinity of developing stylet vacuoles, and fully formed vacuoles are filled with PAS+ material that appears to be derived from the smooth endoplasmic reticulum. At the onset of styletogenesis, a conical sliver of organic material differentiates on the inner surface of the vacuolar membrane. This material displays a species-specific banding pattern in decalcified sections, and apparently acts as a template during calcification of the stylet shaft. After the organic core of the shaft is formed, mitochondria aggregate around the stylet vacuole and presumably help accumulate the calcium used in mineralization of the stylet. A knob-shaped proximal piece is subsequently assembled on the base of the shaft. The proximal piece contains a nonbanded matrix and has electron-dense material at its surface that may help in correctly orienting this region toward the basis during replacement of the central stylet.
    Additional Material: 35 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051790202
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  • 5
    Electronic Resource
    Electronic Resource
    The ultrastructure of venom-producing cells in Paranemertes peregrina (Nemertea, Hoplonemertea) (1983)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 177 (1983), S. 89-107 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nemertean Paranemertes peregrina uses its long, eversible proboscis to capture nereid polychaetes. During prey capture, the glandular epithelium of the everted proboscis secretes a sticky venom that contains a potent neurotoxin. In this study, the ultrastructure of the venom-producing epithelium is examined before and after capture of nereid prey. Four types of cells can be distinguished in the glandular epithelium, based on the shape and staining properties of their secretory products. The cells contain fusiform or coalescent types of rhabdoids, acidophilic granules, or flocculent material. All four cell types occur in the anterior part of the proboscis, but only cells with acidophilic granules have been observed in the posterior chamber. The glandular epithelium of the anterior chamber secretes sheets of venomous mucus that are composed of the four types of secretory products fused together, while the epithelial cells of the posterior chamber produce a granulated discharge. Cells that contain flocculent material also occur in the epidermis of P. peregrina. The flocculent material is believed to contain the toxic component of the venom, as its distribution in the anterior proboscis chamber and body wall correlates with previous reports of toxin concentrations that were derived from assays of tissue extracts.
    Additional Material: 32 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051770108
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  • 6
    Electronic Resource
    Electronic Resource
    The ontogeny of shell secretion in Terebratalia transversa (brachiopoda, articulata) I. Development of the mantle (1985)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 183 (1985), S. 233-250 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphology of the mantle in free-swimming and metamorphosing larvae of the articulate brachipod Terebratalia transversa has been examined by scanning and transmission electron microscopy. The mantle begins to form approximately 2 days after fertilization and subsequently develops into a skirtlike lobe that encircles the middle region of the larval body. A simple epithelium covers both the outer surface of the mantle lobe and the inner side situated next to the pedicle lobe of the larva. During metamorphosis, the mantle lobe is everted over the anterior end of the larva. Thus, the epithelium covering the outer part of the mantle lobe in the larva subsequently becomes the inner epithelium of the juvenile mantle. Similarly, the inner epithelium of the larval mantle lobe represents the future outer epithelium of the juvenile mantle. In free-swimming larvae, the prospective outer mantle epithelium contains two types of cells, called “lobate” and “vesicular” cells. Lobate cells initially deposit a thin layer of amorphous material, and vesicular cells produce ovoid multigranular bodies. Following settlement at about 5 days postfertilization, the vesicular cells secrete an electron-dense sheet that constitutes the basal layer of the developing periostracum. Within several hours to a day thereafter, reversal of the mantle lobe is rapidly effected, apparently by contractions of the pedicle adjustor muscles.
    Additional Material: 30 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051830302
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  • 7
    Electronic Resource
    Electronic Resource
    The ontogeny of shell secrtion in Terebratalia transversa (brachiopoda, articulata) II. Formation of the protegulum and juvenile shell (1985)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 183 (1985), S. 251-271 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fine structure of the shell and underlying mantle in young juveniles of the articulate brachiopod Terebratalia transversa has been examined by electron microscopy. The first shell produced by the mantle consists of a nonhinged protegulum that lacks concentric growth lines. The protegulum is secreted within a day after larval metamorphosis and typically measures 140-150 μm long. A thin organic periostracum constitutes the outer layer of the protegulum, and finely granular shell material occurs beneath the periostracum. Protegula resist digestion in sodium hypochlorite and are refractory to sectioning, suggesting that the subperiostracal portion of the primordial shell is mineralized. The juvenile shell at 4 days postmetamorphosis possesses incomplete sockets and rudimentary teeth that consist of nonfibrous material. The secondary layer occurring in the inner part of the juvenile shell contains imbricated fibers, whereas the outer portion of the shell comprises a bipartite periostracum and an underlying primary layer of nonfibrous shell. Deposition of the periostracum takes place within a slot that is situated between the socalled lobate and vesicular cells of the outer mantle lobe. Vesicular cells deposit the basal layer of the periostracum, while lobate cells contribute materials to the overlying periostracal superstructure. Cells with numerous tonofibrils and hemidesmosomes differentiate in the outer mantle epithelium at sites of muscle attachments, and unbranched punctae that surround mantle caeca develop throughout the subperiostracal portion of the shell. Three weeks after metamorphosis, the juvenile shell averages about 320 μm in length and is similar in ultrastructure to the shells secreted by adult articulates.
    Additional Material: 45 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051830303
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  • 8
    Electronic Resource
    Electronic Resource
    An ultrastructural study of larval settlement in the sea anemone Urticina crassicornis (Cnidaria, Actiniaria) (1985)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 186 (1985), S. 237-253 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Laboratory-reared larvae of the sea anemone Urticina (= Tealia) crassicornis have been examined by electron microscopy prior to and following settlement on algal substrata. At 18 days postfertilization, the free-swimming planula larva measures about 600 μm long. A stomodaeal invagination occurs at the narrow end of the larva and connects with a solid mass of endoderm in the core region. The endoderm possesses septa with well-developed myonemes and is situated subjacent to a thin sheet of mesoglea. The uniformly ciliated ectoderm that constitutes the outer layer of the larva contains: (1) spirocysts, (2) nematocysts, (3) mucus, (4) three types of membrane-bound granules, (5) a basiepithelial nerve plexus, and (6) a few nongranular cells that may represent sensory neurons. Within several minutes after the introduction of the algal substratum, the planula characteristically directs its broadened aboral end toward the alga and secretes a refractile sheet of material. As the aboral end attaches to the substratum, the larva becomes noticeably shorter along its oral-aboral axis, presumably owing to the contractions of myonemes that are located within the endodermal septa. All three types of granules and the ectodermal mucoid substances are exocytosed during settlement, but spirocysts and nematocysts characteristically remain undischarged. Ovoid, PAS+ granules are believed to be at least partly responsible for adhesion, since these granules are concentrated at the aboral end prior to settlement and are somewhat similar in ultrastructure to putative viscid granules produced by other species. Contrary to a previous report based on light microscopy, no discrete sensory organ is evident in serial sections of the aboral ectoderm. The ability of planulae to detect suitable substrata appears to depend instead on sparsely distributed sensory cells that occur throughout the larval ectoderm.
    Additional Material: 35 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051860208
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  • 9
    Electronic Resource
    Electronic Resource
    Metamorphosis of the marine bryozoan Membranipora membranacea: An ultrastructural study of rapid morphogenetic movements (1988)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 196 (1988), S. 53-72 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The colonial marine bryozoan Membranipora membranacea produces a planktotrophic cyphonautes larva that is encased by a triangular bivalved shell. Following a relatively long free-swimming phase, the cyphonautes larva settles and undergoes a dramatic metamorphosis to become the sessile progenitor of the colony, referred to as the ancestrula. This paper examines the initial morphogenetic movements of metamorphosis that transform the cyphonautes larva into an incipient ancestrula. At the onset of metamorphosis, contractions of the striated median muscles situated along the anterior and posterior margins of the larva cause a retraction of the larval apical organ and a centripetal movement of the anterior and posterior ends of the larva. Concurrently, the ciliated corona at the base of the larva is pulled within the shell by contractions of the striated lateral muscles. As the larva assumes a more spherical shape, the posterior margins of the shell are spread apart, and the internal sac is everted. Eversion of the sac is apparently achieved by contractions of the lateral muscles that cause a buckling of the shell in the apical-basal direction. The neck region of the everted sac secretes adhesive granules that attach the larva to the substratum. Subsequently, contractions of the nonstriated sac muscles fold the valves of the shell over each other and draw the larva toward the substratum. The initial events of metamorphosis that culminate in the attachment and flattening of the larva are completed in 10-15 seconds. In the subsequent few minutes, the lateral edges of the everted sac fuse with the neighboring margins of the aboral epithelium underlying the shell and thus form the fully sealed body wall of the incipient ancestrula.
    Additional Material: 30 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051960106
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  • 10
    Electronic Resource
    Electronic Resource
    Synthesen in der Carotinoid-Reihe. 13. Mitteilung12. Mitteilung vgl. Helv. 40, 1256 (1957). Synthese von CanthaxanthinHerrn Professor Dr. P. KARRER zum 70. Geburtstag gewidmet (1959)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 42 (1959), S. 841-847 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new synthesis for canthaxanthin, according to the scheme C19 + C2 + C19 = C40 using dehydro-retro-C19-aldehyde and acetylene is described. The synthetic material proved to be identical in its properties with the natural product isolated from Cantharellus cinnabarinus.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19590420326
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