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  • 1
    Electronic Resource
    Electronic Resource
    Existence of a reactive zone in the interrenal gland of reptiles (1972)
    Springer
    Cellular and molecular life sciences 28 (1972), S. 451-453 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Resumen El estudio histofisiológico de la glándula interrenal de un lagarto teído (Cnemidophorus l. lemniscatus) permitió poner de manifiesto la que se denominó zona reactiva de la glándula. Por su situación es periférica, y está constituida por células dispuestas en formaciones redondeadas. Estas células, que tienen normalmente aspecto de menor actividad, responden más rápida e intensamente que las centrales a la acción de la corticotrofina, exógena o endógena, y aparecen entonces más activas que las últimas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02008335
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  • 2
    Electronic Resource
    Electronic Resource
    Taxonomic implications of Prototheca and Chlorella cell wall polysaccharide characterization (1973)
    Springer
    Archives of microbiology 92 (1973), S. 227-233 
    Details
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Four polysaccharide fractions were obtained by acid and alkaline degradation of purified cell walls of Prototheca spp. and Chlorella spp. These fractions were further hydrolyzed and the component sugars identified. Five Prototheca strains and two Chlorella protothecoides strains have essentially similar polysaccharide compositions, which significantly differ from those of C. vulgaris and C. pyrenoidosa. This emphasizes the close affinity of C. protothecoides to Prototheca spp. not shared by other Chlorella spp.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00411203
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  • 3
    Electronic Resource
    Electronic Resource
    Larval salt gland ofArtemia salina nauplii (1974)
    Springer
    Journal of comparative physiology 88 (1974), S. 217-234 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The naupliar stage ofArtemia salina has been found to contain large amounts of an ATPase which requires the presence of Mg++, is stimulated by Na+ and K+, and is sensitive to ouabain. Upon cell fractionation, sixty percent of the Na+K-activated ATPase activity was present in a heavy membrane fraction which accompanied mitochondria, and twenty percent of the activity was found in the microsomal fraction. Separation of the heavy membranes containing the Na+K-activated ATPase from mitochondria was accomplished by sucrose density gradient centrifugation. Kinetic characterization of the Na+K-activated ATPase was examined with both mitochondrial and microsomal preparations. No significant differences were observed between the two preparations. Maximal enzyme activity occurred at pH 7.2 and a temperature of 45 ° C. Half maximal inhibition of enzymatic activity occurred with ouabain concentration of 8 × 10−6 M. Half maximal activation of the enzyme by ATP and MgCl2 occurred at 8 × 10−4 and 1 × 10−3 M, respectively, with an optimal Mg++/ATP ratio of 2.0. NaCl and KC1 (or NH4C1) were required for activity, with half maximal activation at 1 × 10−2 and 9 × 10−3 M (or 2.1 × 10−2 M), respectively. The optimal Na+/K+ ratio was 4.0, although enzymatic activity occurred through a wide range of ratios. In contrast, survival of nauplii was reduced in media in which the Na+/K+ ratio was less than 10. Anatomical localization of the enzyme in nauplii indicated that the abdominal region contained 44% of the total Na+K-activated ATPase activity, while the cephalothoracic region contained 54% of the total activity. Isolated larval salt glands contained 10% or less of the total activity. In contrast, the adult leg segments containing the salt-transporting organs showed 54% of the total Na+K-activated ATPase activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00697956
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  • 4
    Electronic Resource
    Electronic Resource
    Neck organ ofArtemia salina nauplii (1972)
    Springer
    Journal of comparative physiology 80 (1972), S. 239-246 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ability of brine shrimp nauplii (Artemia salina L.) to exist in a wide range of salinities results from an active excretion of sodium ions from the body into the external environment. Localization of NaCl in the neck organ suggests that this is the site of salt secretion. Ultrastructural studies support this view, the structure of the neck organ being characteristic of salt glands in the adult brine shrimp and other organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00694838
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  • 5
    Electronic Resource
    Electronic Resource
    Larval salt gland ofArtemia salina nauplii (1972)
    Springer
    Journal of comparative physiology 80 (1972), S. 247-254 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Naupliar brine shrimp (Artemia salina) have been used to study the differentiation of salt secretory cells. The effects of several kinds of inhibitors on survival of nauplii at various salinities are presented. Results with ouabain indicate that the ability of the nauplii to survive at high salinities is dependent upon the presence of Na++K+-activated ATPase. Puromycin, chloramphenicol and cycloheximide, all inhibitors of protein synthesis, are more effective at high salt concentrations. Inhibitors of RNA synthesis that are primarily extranuclear in mechanism, i.e. rifamycin and ethidium bromide, also show a marked salt dependency. Among inhibitors which were assayed but did not effect survival under any circumstances were mitomycin C, 5-fluorodeoxyuridine and sarkomycin. Those inhibitors which did not show a differential salt sensitivity were actinomycin D and α-amanitin. It is concluded from these data that coincident transcription and translation of both nuclear and mitochondrial genes are involved in the development of the naupliar salt gland.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00694839
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  • 6
    Electronic Resource
    Electronic Resource
    Larval salt gland ofArtemia salina nauplii (1973)
    Springer
    Journal of comparative physiology 82 (1973), S. 277-289 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Naupliar brine shrimp (Artemia salina) have been used to study the salt-dependent regulation of protein synthesis. Measurement of thein vivo rates of protein synthesis was found to be very complex and dependent upon the leucine concentration of the external medium, rate of leucine entry and time of equilibration between various internal pools of leucine. Techniques were developed which permitted the measurement of rates of incorporation ofl4C-L-leucine into naupliar protein at various salinities under conditions that provided the organisms with a constant internal specific activity. It was found that salinities over 0.25 M NaC1 caused decreased rates of protein biosynthesis. A comparison of the rate of protein synthesis in the presence of chloramphenicol, cycloheximide and puromycin indicated that qualitative as well as quantitative changes in synthesis of proteins was directed by the external salinity. A feed-back mechanism based on the partitioning of available energy (ATP) between ion transport and protein synthesis is hypothesized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00694240
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  • 7
    Electronic Resource
    Electronic Resource
    Surface specialization of the larval salt gland inArtemia salina nauplii (1972)
    Springer
    Journal of comparative physiology 79 (1972), S. 97-104 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scanning electron microscopic (SEM) observations of brine shrimp nauplii reveal the dorsal surface of the cephalothorax region to be specialized in structure. During larval differentiation the epithelial layer is transformed from a flat caplike structure into a hemispherical dome that has deep channels coursing through the epithelium. A thin cuticular film covers the epithelial cap but a distinct ruffled edge serves as a boundary that identifies the limits of the organ. These morphological observations support previous finding which indicated this area to be the site of the larval salt gland.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00693621
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  • 8
    Electronic Resource
    Electronic Resource
    Fine structure and function of the alimentary epithelium in Artemia salina Nauplii (1974)
    Springer
    Cell & tissue research 155 (1974), S. 423-436 
    Details
    ISSN: 1432-0878
    Keywords: Brine shrimp ; Artemia salina ; Alimentary tract ; Fine structure, function ; Salt and water absorption ; Osmoregulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the alimentary tract in the second instar nauplius of the brine shrimp, Artemia salina, has been described. The foregut and hindgut of the larva are composed of cuboidal epithelium which is cuticularized. The epithelium of the midgut and gastric caeca is columnar and is characterized by apical microvilli, basal membrane infolds, and abundant mitochondria. The structural characteristics of the midgut cells correlate with previous physiological and biochemical evidence on both adult and larval brine shrimp which indicates that the midgut plays an important role in absorption and osmoregulation in these animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227006
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  • 9
    Electronic Resource
    Electronic Resource
    Ultrastructure of the sexual segments of the kidney in male and female lizards, Cnemidophorus l. lemniscatus (L.) (1973)
    Springer
    Cell & tissue research 144 (1973), S. 325-337 
    Details
    ISSN: 1432-0878
    Keywords: Kidney ; Sexual accessory organs ; Reptiles ; Secretion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Kidneys of adult male and female lizards were studied by electron microscopy, in order to understand the ultrastructure of the collecting duct and a differentiated part thereof, the sexual segment, which is an important accessory sexual organ. First portion of sexual segment in males: The cells are filled with large secretory granules of a wide range of opacities. The granular endoplasmic reticulum is abundant; basal formations of superimposed flat cisternae are frequent. Distended vesicles and microvesicles prevail in the supranuclear, well developed Golgi apparatus. Evidences indicate that secretion of these cells is holocrine. Second portion of sexual segment in males: All of the secretory granules are apical in location and relatively electron-opaque; they show a denser core. This core is formed by a substance which, after lying in contact with ribosomes, enters the secretory vesicles of the highly developed Golgi apparatus. A lighter substance is then condensed around it. The secretion of the granules is merocrine. The granular endoplasmic reticulum is very abundant in these cells, but basal ergastoplasmic formations are lacking. Sexual segment in females: The cells show features similar to those of the male first portion, but they are smaller. Undifferentiated collecting duct: Most of the cells are mucigenic. They have small ovoid, apical secretory granules. The density of the granules varies from cell to cell; when they are electron-lucent, they exhibit laminar or dotted opaque figures. Moderately developed Golgi apparatus and granular endoplasmic reticulum, as well as elongated mitochondria, occur in mucigenic cells. Intercalated among the latter are non-secretory cells. They have very abundant mitochondria, numerous microvilli, many pinocytic and smooth-membrane vesicles, whereas the organelles participating in synthetic processes are poorly developed; their function is most likely related to active solute transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307580
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of metopirone on the structure of endocrine glands in the male lizard, Cnemidophorus l. lemniscatus (L.) (1972)
    Springer
    Cell & tissue research 135 (1972), S. 27-43 
    Details
    ISSN: 1432-0878
    Keywords: Endocrine glands ; Male sexual organs ; Reptiles ; Influence of Metopirone ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Adrenals, pituitary glands, thyroids, testes and kidneys of metopirone-treated and control male lizards were studied by light microscopy. Pituitary-interrenal axis: A great hypertrophy and hyperplasia of the interrenal cells and the pituitary corticotrophs were found in the experimental group. Pituitary-thyroid axis: Metopirone-treated animals showed a moderate hypertrophy and degranulation of pituitary thyrotrophs, and signs of uneven hyperactivity of the thyroid. Pituitary-testicular axis: By effect of metopirone, a marked regression of pituitary interstitiotrophs and a virtual disappearance of the testicular interstitial gland took place. The second portion of the kidney sexual segments appeared degranulated as in castrated animals. The pituitary folliculotrophs and the seminiferous epithelium of the testis did not show alterations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307085
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