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  • Life and Medical Sciences  (112)
  • Biochemistry and Biotechnology
  • 1935-1939  (112)
  • 1936  (112)
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  • 1935-1939  (112)
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 59 (1936) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 59 (1936), S. 1-10 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The paraphysis of adult Amblystoma is made up of low columnar ependymal epithelit m which forms the paraphyseal tubules which end blindly and which communicate with one another by a common mouth with the third ventricle. Between the paraphyseal tubules venous sinusoids anastomose freely with one another forming a complicated rete. The sinusoids are made up entirely of endothelium. The blood supply to the paraphysis is entirely venous.Mitochondria were found in great abundance in the paraphysis of one female just previous to laying. Other specimens showed very few present. No conclusions can be drawn from these few observations as to the relationship between physiological activity and cellular structures.The Golgi apparatus was observed definitely localized between the nucleus and the ventricular end of the cell.Many large crystalloids were also observed to be localized between the nucleus and the ventricular end of the cell.Intercellular spaces are readily observed in sections stained with Mallory's connective tissue stain. Nassonow's osmic acid technique for the Golgi apparatus and Benda's crystal violet and alizarin stain clearly bring out the intercellular canals. Acid fuchsin stained particles within the intercellular spaces are more abundant toward the sinusoids than the cavities of the paraphyseal tubules. The intercellular canals have not been seen to communicate with either the sinusoids or the cavities of the paraphyseal tubules in any of the preparations observed.
    Additional Material: 8 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 59 (1936), S. 91-112 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Increases in weight, total body length, and width and length of the head capsule of Japanese beetle larvae were studied. Since the progression factors decreased with succeeding molts and exhibited considerable variation it was concluded that Przibram's principle is inapplicable. Cells were counted in the mid-intestine and brain. Columnar cells of the mid-intestine were measured. The data show: (a) No increase in cell number occurs at the time of molting. (b) The progression in weight and length cannot be correlated with an increase in cell number. In the first instar the progression for increase in weight was 5.73; while for increase in cell number, it was 1.67 for the mid-intestine, and 1.19 for the brain. In the second instar, the corresponding figures were 5.24, 1.98 and 1.69. In the third instar average weight increased 3.18 times, but there was practically no increase in cell number. Thus, molting does not represent a definite increase in number of cells of the insect's body as suggested by Przibram and Megusar, and Bodenheimer's method of calculating cell divisions seems to have no factual basis. Increase in size of the larva is largely due to an increase in cell size. The ratio of increase in total cell volume of the columnar cells of the mid-intestine is approximately equal to the ratio of weight increase.
    Additional Material: 2 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 59 (1936), S. 123-161 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An atypical euchromosome, characterized by the large size and deep stainability of its chromomeres during the meiotic prophase, occurs in representatives of seven genera of Acridinae, viz., Chorthippus curtipennis, Euchorthippus pulvinatus, Stenobothrus lineatus, Omocestus ventralis, Stauroderus biguttulus, Gomphocerus rufus, and Aeropedellus clavatus. This element, which is termed the ‘megameric chromosome,’ stains more deeply than the other euchromosomes also during interkinesis and early spermiogenesis. The megameric chromosomes of the individual exhibit striking similarity in the number, size, and arrangement of their chromomeres through successive stages of the meiotic prophase. All the evidence from cytological study indicates that these chromosomes are intergenerically homologous. This is chiefly significant in the support it gives to the theory of chromosome individuality. The heteromorphic megameric tetrad of one individual of S. biguttulus - unequal because of a deficiency - usually undergoes segregation in the second division. The megameric chromosomes display splits previous to synapsis. Pairing begins at their proximal ends and proceeds distally. All the euchromosomes of the spermatid nucleus show splits in preparation for the first cleavage division of the zygote.
    Additional Material: 1 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 59 (1936), S. 215-223 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In a comparative study of the branchial epithelium of fishes we find the occurrence of three distinct types and seven subtypes of intra-epithelial glands which are in intimate association with the branchial epithelium of fishes.These glands have been classified according to their morphological patterns, cytoplasmic content and other features dealing with structural complexity.Although these structures arrange themselves in a graded series which become increasingly more and more complex, there does not appear to be any definite correlation between the structural complexity of the glands, and the apparent evolutionary history of the fishes.We conclude from the characteristic arrangement, relationships, and specific staining reactions that these structures are intra-epithelial mucous glands.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 60 (1936), 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: Differing from hitherto known spermatophores, these are found to have the form of a loop with a thick body and the slender ends twisted together.Also one end bears a spiral row of triradiate spicules, unique in being chitinoid secretions. Each is formed within a vacuole of a cell of a small gland found in the males. The ends of the spermatophores hold sperms, but the main mass consists of granules of problematical value. Spermatophores after discharge are stored up within the female, where remnants of them remain indefinitely.For the first time stages in the formation of spermatophores were found within the males. The head organ in the male is found to be more complex than hitherto known in this genus. A special head organ in the female is described for the first time in this family. An hypothesis is advanced as to the possible use of these male and female head organs in transfer of spermatophores. The suggestion is made that in this family the spermatophores and their organs of transfer and of storage may serve as generic characters.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 60 (1936), S. 243-259 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The post-embryonic growth of the notochord, sensory retinal cells, cartilage and gut epithelium in frog tadpoles, trout and lamprey is described. Increase in the number of notochord and sensory retinal cells results only from the mitotic division of cells which have not yet undergone the structural modifications characteristic for these cells. The specialized and functional cell does not divide. In the frog tadpole the cartilage cells increase by mitotic division of the fully-formed and functional cell: in addition there are centers of proliferation consisting of small, rapidly-dividing cells. The trout is similar except that there are no centers of proliferation, in addition amitotic division occurs. The gut epithelium grows by mitotic division of the functional constituent cells. During division the cell assumes a spherical shape and its functional activities are suspended.
    Additional Material: 7 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 60 (1936), S. i 
    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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  • 9
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two sizes of cells are found in the mid-gut epithelium of late embryos. The larger cells contain nuclei having twice the number of prochromosomes and nearly twice the volume as compared with the nuclei of the smaller cells. During each larval instar, the nuclei of the functional mid-gut epithelium nearly double their volume and there is a corresponding increase in the amount of chromatin. It is suggested that chromosome division without nuclear division occurs in these epithelial cells during the pre-ecdysial periods of each instar. The mid-intestinal epithelial cells and their nuclei undergo characteristic changes during the feeding and pre-ecdysial periods of each instar. Prochromosomes as well as cytoplasmic globules, which represent a cytoplasmic diminution process, are visible in the latter period. The regeneration cells which give rise to the pupal and mid-gut epithelia have origin from the small embryonic mid-gut cells and from nuclei and cytoplasm derived from the larval epithelium by means of an apparent ‘pseudoreduction’ of the large larval nuclei during the late third and fourth instars.
    Additional Material: 1 Tab.
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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 bodies of Eberth in the skins of tadpoles appear in young stages as fine threads and develop into heavy, amorphous masses in close contact with the basal membranes of the epidermal cells. They possess extensions which pass from the epidermal cells through their membranes into the corium. During metamorphosis, when the amount of dermal connective tissue is greatly increased, the bodies disappear the more distal first and the most proximal latest. The processes which pass into the dermis are the last parts to remain visible. Examination of a series of stages suggests that they pass through the cell membranes of the epidermis and into the corium. The bodies then, may be regarded as reserve accumulations of secreted material which are used up in the formation of dermal connective tissue. This explanation accounts for three otherwise unexplained peculiarities of the skin of the developing frog: (1) the presence and growth of the bodies of Eberth; (2) their disappearance during metamorphosis; (3) the sudden large increase in connective tissue fibers of the dermis at metamorphosis.
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