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  • SPACE SCIENCES  (1,748)
  • Cell & Developmental Biology
  • 1970-1974  (1,935)
  • 1972  (1,935)
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  • 1970-1974  (1,935)
Year
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 136 (1972), S. 1-21 
    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 wing epidermis of the giant silkmoth, Hyalophora cecropia, was studied during pupal diapause and the first half of development to the adult. In diapause, the generalized epidermal cells are characterized by many free ribosomes, some vesicles and small lamellae of rough endoplasmic reticulum, some scattered short mitochondria and a few small Golgi complexes. During the early states of post-diapause development, before and after the time of apolysis (separation of the epidermis from the overlying cuticle), there is a marked increase in structures often associated with synthetic functions, such as polyribosomes, lamellate rough endoplasmic reticulum and Golgi complexes. On day five of post-apolysis development, just after the appearance of scale-forming and socket-forming cells, the generalized epidermal cells lay down the cuticulin layer of the adult cuticle. At this stage and later, the polyribosomes and lamellate rough endoplasmic reticulum decrease in abundance. Cell nuclei show three phases of temporary transition from predominantly lobed to predominantly round profile, which correspond to periods of reported DNA synthesis. Throughout this developmental process, therefore, there is good correlation of fine structure with changes in macromolecular synthesis recorded elsewhere.
    Additional Material: 3 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 136 (1972), S. 79-107 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The circulatory system of Pollicipes polymerus exhibits a high degree of organization which precludes it from being referred to as an open system. The system is arbitrarily divided into four parts: (1) the circulation of the peduncle and mantle; (2) the distributive circulation of the body, which provides hemolymph to most of the cephalic gut, to the maxillary gland, and to the cirri; (3) the peripheral circulation which distributes blood from the cirri to the peripheral areas of the thoracic region, to most of the thoracic gut, and from the scutal sinus to the peripheral areas of the cephalic region; and (4) the collecting circulation, which conveys hemolymph mostly from the peripheral circulation of the body to the peduncle. There also may be a circulation that is comparable to the vertebrate lymphatic system.Pumping of hemolymph can be attributed to three pairs of skeletal muscles that compress the dorsolateral channels. These muscles are unique for crustacean muscles in that they do not appear to be striated.The rostral vessel appears to be a vestige of a heart in which the pump muscles have been lost. There is a similarity of the rostral vessel to the heart of Calanus finmarchicus (a copepod). This is additional evidence linking the cirripeds with the copepods within the Maxillopoda.Electron microscope observations of the walls of the midsagittal vessels indicate that there is a more or less random layering of cellular and noncellular elements within the wall. Muscle cells appear to be incorporated in the vessel wall.
    Additional Material: 2 Ill.
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  • 3
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Oogenesis in the anuran Xenopus laevis can be divided into six stages based on the anatomy of the developing oocyte. Stage I consists of small (50 to 100 μ) colorless oocytes whose cytoplasm is transparent. Their large nuclei and mitochondrial masses are clearly visible in the intact oocyte. Stage II oocytes range up to 450 μ in diameter, and appear white and opaque. Stage I and II are both previtellogenic. Pigment synthesis and yolk accumulation (vitellogenesis) begins during Stage III. Vitellogenesis continues through Stage IV (600 to 1000 μ), the oocytes grow rapidly, and the animal and vegetal hemispheres become differentiated. By Stage V (1000 to 1200 μ) the oocytes have nearly reached their maximum size and yolk accumulation gradually ceases. Stage VI oocytes are characterized by the appearance of an essentially unpigmented equatorial band. They range in size from 1200 to 1300 μ, are postivtellogenic and ready for ovulation. These stages of oocyte development have been correlated with physiological and biochemical data related to oogenesis in Xenopus.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 136 (1972), S. 191-209 
    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 epidermis at different stages of the shedding cycle has been studied in Anolis carolinensis. Cells of the germinal layer are morphologically similar at all stages in the cycle. Immediately after leaving the germinal layer all daughter cells resemble one another closely. However, they later acquire specific ultrastructural features that enable them to be classified into six distinct fully differentiated types corresponding to the grouping previously set forth by light microscopy. A comparison of cytoplasmic filament size with the known X-ray diffraction data suggests that the Oberhautchen and β-layer contain a protein similar to that of avian feather; the protein in the α-layer and lacunar tissue is similar to that in mammalian hair, and the mesos layer cells probably contain a mixture of feather and hair-like proteins. The nature of the amorphous cytoplasmic material in the mature clear layer is as yet unknown.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 136 (1972), S. 247-254 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The interspecific variation in the positional and mesenteric relationship of the mammalian oviduct to the ovary observed among 41 species is summarized by distinguishing eight morphological types of relationship. The recognition of types is based on wide species differences in: the position of the oviduct with reference to the mesosalpinxal fold and ovary; the extent to which oviducal mesenteries enclose the ovary in a periovarial sac; the degree of closure and method of formation of the peritoneal opening to the periovarial sac; and the morphology of the oviduct.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 136 (1972) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 136 (1972), S. 227-245 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The stellate cell in the pars distalis of Anolis carolinensis has been studied with the electron microscope. This cell type is characterized by the lack of secretory granules, and it possesses elongate processes that insert between secretory cells. Few cytoplasmic filaments are present in these processes, and desmosomes linking them to adjacent stellate cells or to secretory cells are seen infrequently in control animals. Stellate cells are often encountered in the caudal half of the pars distalis, but they are less commonly found in the rostral half. In animals undergoing thyroidal depression, thyroidectomy cells arise in the caudal pars distalis. Concurrently, stellate cells of that region hypertrophy and exhibit increased numbers of desmosomes, complex intercellular junctions, and micropinocytotic vesicles. Injected horseradish peroxidase penetrates the intercellular spaces, enters the micropinocytotic vesicles, and is transported to the interior of the stellate cell. It is suggested that stellate cells in Anolis under certain conditions may transport materials between the bloodstream and secretory cells.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 136 (1972), S. 459-493 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The relatively undifferentiated cells comprising the prefollicular epithelium of the fourth and fifth instar of the reduvid bug Rhodninus prolixus are flattened and contain the regularly occurring organelles, lipid droplets, and aggregates of glycogen-like particles. These cells transform into the adult prefollicular tissue.During vitellogenesis there is a gradual shortening of the cells of the follicular epithelium and an increase in the size of the intercellular space between them and between follicle cells and oocyte. The follicle cells are binucleate, contain numerous microtubules, rough endoplasmic reticulum, many free and aggregate ribosomes, and Golgi complexes. They are associated with each other by gap junctions. Only the follicle cells on the lateral aspects of the oocyte exhibit the development of large extracellular spaces while those at the apical end, that produces the cap, remain tall and closely apposed to each other during vitellogenesis. The normal morphology of the follicle cells over various areas of the oocyte suggests that shape and/or volume changes of these cell may be important in regulating the access of yolk proteins to the colemma.Subsequent to vitellogenesis the follicle cells become cuboidal and once again become closely apposed to each other. They contain much rough endoplasmic reticulum and produce the secondary coat.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 136 (1972), S. 495-503 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The results of histochemical tests performed on the type “B” dermal gland in Rhodnius and the Verson's gland in Calpodes at different stages in their secretory cycle are presented. The secretions of both glands are slightly acidic sulphated mucosubstances. They differ in their main carbohydrate component which in Rhodnius is hyaluronic acid and in Calpodes is sialic acid. The glands, though structurally similar, differ in size, number, and development.
    Additional Material: 22 Ill.
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  • 10
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The atresia of post-ovulatory and pre-ovulatory follicles of the viviparous smooth dogfish, Mustelus canis, is compared for approximately the first fourth of an 11 month gestation. A thick collagenous sheath and numerous tubules in the theca identify the large, folded stage A post-ovulatory follicle. In stage B the tubules have been filled by cells to form “islands.” In stage C the entire structure is greatly diminished, adjacent islands tend to fuse, the collagenous sheath is virtually gone and the granulosa is degenerating. Preovulatory follicles from large, yolky oocytes pass through four stages beginning with yolk phagocytosis by granulosa cells of the villi (stage I), which are long and granular in stage II; villi fuse, theca cells increase greatly, fill with granules (stage III), encroach on the granulosa and disperse it into small groups of cells which finally disappear (stage IV) leaving a mass of thecal cells. A special type of pre-ovulatory follicle from small non-yolky oocyte atresia exhibits prominent thecal tubules and an unusual arrangement of granulosa cells. This follicle appearrs to enlarge during the summer, becoming multilobed; few granules are present.The distribution of lipid in frozen sections, stained by Oil red O, is described for all types of follicles. Schultz and Lewis and Lobban tests for steroids were made on frozen sections with corresponding results. Positive green tests indicating the presence of steroids or possible steroidogenesis were limited to: (1) one post-ovulatory follicle, in the islands; (2) four stage III and seven late stage IV pre-ovulatory yolky atretic follicles; (3) two special atretic follicles. The special atretic follicle appears to be a unique feature of M. canis and it is suggested tentatively that it may be related to viviparity.
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