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  • Electron microscopy  (46)
  • Nicotiana  (26)
  • Springer  (72)
  • American Chemical Society
  • Annual Reviews
  • Oxford University Press
  • 2005-2009
  • 1990-1994
  • 1980-1984  (72)
  • 1980  (72)
Collection
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  • Springer  (72)
  • American Chemical Society
  • Annual Reviews
  • Oxford University Press
  • Wiley-Blackwell  (1)
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  • 2005-2009
  • 1990-1994
  • 1980-1984  (72)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Properties and regulation of adenosine 5′-phosphosulfate sulfotransferase from suspension cultures ofNicotiana sylvestris (1980)
    Springer
    Planta 150 (1980), S. 140-143 
    Details
    ISSN: 1432-2048
    Keywords: Adenosine 5′-phosphosulfate sulfotransferase ; Cell suspension culture ; Cysteine ; Enzyme regulation ; Nicotiana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The properties and the regulation of adenosine 5′-phosphosulfate sulfotransferase extracted from cell suspension cultures ofNicotiana sylvestris was investigated. Optimal adenosine 5′-phosphosulfate sulfotransferase activity was obtained from the cells by extraction with 0.1 M tris-HCl, pH8.0, containing 2 M MgSO4 and 10 mM dithioerythritol. The K m for adenosine 5′-phosphosulfate in the sulfotransferase reaction was about 11 μM. Adenosine 5′-phosphosulfate in concentrations above 50 μM were inhibitory. The extratable adenosine 5′-phosphosulfate sulfotransferase activity decreased during cultivation with sulfate as the sole sulfur source, but after about 3 days it reached a constant level (50 to 100 nmol activated sulfate transferred h-1 mg-1 protein) which was maintained for at least 24 h. Addition of 0.5 mM cysteine to the culture medium decreased the extractable adenosine 5′-phosphosulfate sulfotransferase activity and blocked growth completely. With 0.1 mM cysteine an enzyme level of about 10% of the initial value was reached within 6 to 12 h without significant inhibition of growth. The added cysteine was absorbed rapidly and after 24 h cysteine could no longer be detected in the medium. Before the cysteine was completely depleted, the activity of adenosine 5′-phosphosulfate sulfotransferase started to increase, reaching ultimately a level which was comparable to the initial value.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00582357
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  • 2
    Electronic Resource
    Electronic Resource
    Ribosylzeatin and zeatin in tobacco crown gall tissue (1980)
    Springer
    Planta 147 (1980), S. 269-273 
    Details
    ISSN: 1432-2048
    Keywords: Crown gall ; Cytokinins ; Nicotiana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cytokinins were extracted from two cultures of tobacco crown gall tumor tissue: an unorganized tissue and a teratoma which produced leafy shoots. On Sephadex LH-20 column chromatography, extracts of both types of tissue yielded two peaks of cytokinin activity with elution volumes similar to ribosylzeatin and zeatin. Ribosylzeatin and zeatin were detected and quantified by coupled gas chromatography — mass spectrometry selected ion monitoring (GC/MS SIM), comparable quantities being found in the two extracts. Full mass spectral evidence for the presence of ribosylzeatin in both tissues was obtained. No evidence was found for the presence of N6-(Δ2-isopentenyl)adenosine (i6Ade) or N6-(Δ2-isopentenyl)adenine (i6Ade) although these compounds have been reported to occur in cytokinin-habituated tobacco callus tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379831
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  • 3
    Electronic Resource
    Electronic Resource
    Multistage disruption of protoplasts by dikegulac (1980)
    Springer
    Planta 147 (1980), S. 274-276 
    Details
    ISSN: 1432-2048
    Keywords: Cell division ; Dikegulac ; Lysis ; Nicotiana ; Plasmalemma ; Protoplasts ; Tonoplast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dikegulac (2,3:4,6 di-o-isopropylidine-2-keto-I-gulonate) is a growth regulator used to differentially kill terminal apices, and it analogously inhibits basic metabolic functions in dividing cells, but not stationary cells, in suspension culture. This report demonstrates an analogous situation in isolated tobacco protoplasts. At the lowest concentrations, dikegulac partially suppresses division of the protoplasts. Higher concentrations are required to produce visual cytoplasmic damage to the protoplasts, which probably first occurs at the level of the plasmalemma, as the vacuoles can be released intact. Later, tonoplast disruption occurs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379832
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  • 4
    Electronic Resource
    Electronic Resource
    Isolation of abscisic acid-resistant variants from tobacco cell cultures (1980)
    Springer
    Planta 148 (1980), S. 97-102 
    Details
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Cell cultures ; Nicotiana ; Variants, resistant ; Water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The goal of this work was to begin a genetic study of the molecular mode of action of abscisic acid (ABA), by isolating variant cultured cells resistant to the hormone, or to a factor which induces ABA synthesis, namely water stress. Cell cultures of Nicotiana tabacum L. cv. Wisconsin 38 and N. silvestris Speg. and Comes were chosen as the experimental materials. Studies of the effects of the two stresses on the growth of the cultures demonstrated that ABA or water stress imposed by mannitol could completely inhibit growth. These effects arose in both cases from a constant reduction of the growth rate of the cells throughout the culture period. Mannitol also induced an increase in ABA content of the cells and media of suspension cultures, although not to the concentrations required to achieve the same degree of growth inhibition when the hormone was applied exogenously.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386408
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  • 5
    Electronic Resource
    Electronic Resource
    Suitable conditions for characterization, identification, and isolation of the mRNA of the small subunit of ribulose-1,5-bisphosphate carboxylase from Nicotiana sylvestris (1980)
    Springer
    Planta 148 (1980), S. 211-216 
    Details
    ISSN: 1432-2048
    Keywords: mRNA ; Nicotiana ; Protein synthesis ; Ribulose-1,5-bisphosphate carboxylase ; RNA (messenger) ; Translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The products synthesized in vitro by messenger RNA (mRNA) extracted from Nicotiana sylvestris were analyzed by electrophoresis on polyacrylamide slab gels. Only three of the major polypeptides synthesized are considered here: P55, P32, and P20. P55 and P32 were translated from chloroplast mRNA. P55 corresponds to the large subunit of ribulose-1,5-bisphosphate (RuP2) carboxylase; P32 is probably a chloroplast membrane protein. P20, the polypeptide synthesized from cytoplasmic poly(A)+ RNA, is the precursor of the small subunit of RuP2 carboxylase. The balance between P20 and P32, in which their relative proportions varied inversely, was regulated by the age of the leaves and the time of illumination; we took advantage of this phenomenon to isolate the mRNA from the small subunit in relatively large amounts. This mRNA has a molecular weight of 350,000.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00380029
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  • 6
    Electronic Resource
    Electronic Resource
    Polysomes from expanded tobacco leaves (1980)
    Springer
    Planta 148 (1980), S. 491-497 
    Details
    ISSN: 1432-2048
    Keywords: Leaves (polysomes) ; Nicotiana ; Polysomes ; Poly(A)+ RNA ; Protein synthesis ; RNA (polysomal, polyA+)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The isolation of intact polysomes from leaves of tobacco (Nicotiana tabacum L.) is dependent on the age and state of development of leaves. Undegraded polysomes from young leaves in the early stages of expansion can be isolated easily by extracting the leaves in ice-cold extraction buffer (200 mM tris(hydroxymethyl)aminomethylmethane(Tris)-HCl, pH 9.0; 400 mM KCl; 200 mM sucrose; 35 mM MgCl2). Medium-size leaves give best yields of undegraded polysomes when extractions are carried out in the above buffer and in the presence of ethyleneglycol-bis-(β-amino-ethyl ether)-N,N′-tetracetic acid (EGTA) and mercaptoethanol. Isolation of polysomes from large, nearly fully expanded (mature) leaves requires all of the above plus diethyldithiocarbamate (DIECA) in the extraction medium. An extraction medium consisting of 25 mM EGTA, 0.01 M mercaptoethanol, 25 mM DIECA and 0.5% of the nonionic detergent, Nonidet-P40 (NP 40) was found to be very suitable for extraction of polysomes from all developmental stages of leaves. The polysomes extracted in the above medium showed active translation of protein in the wheat-germ in-vitro protein-synthesizing system. The translational products were similar when translations were carried out directly with polysomes or polysomal RNA, or polysomal poly(A)+ RNA from tobacco leaves. Poly(A)− polysomal RNA was a poor template in the in-vitro wheat-germ system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02395320
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  • 7
    Electronic Resource
    Electronic Resource
    Nutritional requirements of protoplast-derived, haploid tobacco cells grown at low cell densities in liquid medium (1980)
    Springer
    Planta 149 (1980), S. 7-18 
    Details
    ISSN: 1432-2048
    Keywords: Auxin metabolism ; Cell suspensions (low density) ; Medium conditioning ; Nicotiana ; Nitrogen metabolism ; Protoplasts ; Vitamin requirements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Preliminary attempts to define a completely synthetic medium able to support divisions of haploid tobacco mesophyll protoplasts at low initial densities have failed. High protoplast concentrations together with large amounts of naphtaleneacetic acid in the medium (3 mg l-1 NAA) were required for maximal induction of protoplast division. However, cell suspensions derived from haploid protoplasts after four days of preculture at high initial cell densities could be diluted to densities as low as 1–4 cells ml-1, provided the concentration of NAA in the medium was lowered to below 0.3 mg l-1. The optimal NAA supply for low cell density growth was affected by the nature of the nitrogen source. A simple minimal medium which supports the growth of these haploid cells with a plating efficiency of 30–40%, independent of the cell density in the range of 1–4 to 3·104 cells ml-1, has been established. In this medium inositol was the only vitamin stringently required for growth. Growth of cells at low densities was also possible in a medium initially containing 3 mg l-1 NAA, provided it was conditioned by the growth of protoplasts at high densities. Preliminary experiments with [14C]NAA showed that the amount of free NAA remaining in the medium after preincubation at high densities was drastically reduced. Simultaneously, NAA conjugates accumulated in the medium. The implications of these results are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386221
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  • 8
    Electronic Resource
    Electronic Resource
    The effect of light on the production of ethylene from 1-aminocyclopropane-1-carboxylic acid by leaves (1980)
    Springer
    Planta 149 (1980), S. 196-199 
    Details
    ISSN: 1432-2048
    Keywords: 1-Aminocyclopropane-1-carboxylic acid ; Avena ; Ethylene ; Etiolation ; Light (ethylene production) ; Nicotiana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract White light inhibits the conversion of 1-amino-cyclopropane-1-carboxylic acid (ACC) in discs of green leaves of tobacco (Nicotiana tabacum L.) and segments of oat (Avena sativa L.) leaves by from 60 to 90%. Etiolated oat leaves do not show this effect. The general nature of the effect is shown by its presence in both a mono- and a dicotyledon. Since the leaves have been grown and pre-incubated in light, yet can produce from 2 to 9 times as much ethylene in the dark as in the light, it follows that the light inhibition is fully reversible. The inhibition by light is about equal to that exerted in the dark by CoCl2; it can be partly reversed by dithiothreitol and completely by mercaptoethanol. Thus the light is probably acting, via the photosynthetic system, on the SH group(s) of the enzyme system converting ACC to ethylene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00380882
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  • 9
    Electronic Resource
    Electronic Resource
    Correlation between the nicotine content of tobacco plants and callus cultures (1980)
    Springer
    Planta 149 (1980), S. 205-206 
    Details
    ISSN: 1432-2048
    Keywords: Callus cultures ; Nicotiana ; Nicotine ; Tissue cultures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Callus cultures of two low-alkaloid lines of Nicotiana tabacum L. had considerably lower nicotine contents than cultures from the respective highalkaloid cultivars which were isogenic except for the two loci for alkaloid accumulation. Thus, there was a strong correlation between the nicotine content of callus cultures and the plants from which they were derived.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00380884
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  • 10
    Electronic Resource
    Electronic Resource
    Stimulation by abscisic acid of RNA synthesis in discs from healthy and tobacco mosaic virus-infected tobacco leaves (1980)
    Springer
    Planta 150 (1980), S. 349-353 
    Details
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Nicotiana ; Ribonucleic acid synthesis ; Tobacco mosaic virus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Uptake of abscisic acid from the culture medium by discs of healthy and tobacco mosaic virus-infected tobacco leaves was measured. Small (two to five-fold) increases in abscisic acid concentration in discs caused increases in rates of [3H]uridine and [3H]adenine incorporation into total nucleic acid, virus RNA and host ribosomal RNA. Net accumulation of virus RNA was also enhanced by abscisic acid. This evidence for stimulation of RNA synthesis is compared with previous reports showing inhibition of RNA synthesis in other tissues. It is suggested that the increase in endogenous abscisic acid caused by tobacco mosaic virus infection may be at least partly responsible for observed increases in rates of RNA synthesis after infection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00390168
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  • 11
    Electronic Resource
    Electronic Resource
    Isolation of abscisic acid-resistant variants from tobacco cell cultures (1980)
    Springer
    Planta 148 (1980), S. 103-107 
    Details
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Cell cultures ; Nicotiana ; Variants, resistant ; Water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Variant clones were isolated from Nicotiana silvestris Speg. et Comes cell cultures at low frequencies following severe abscisic-acid (ABA) or mannitol-induced water-stress treatments of plated cells. N. tabacum L. variants were not recovered. Variants from the ABA selection experiments exhibited a 10-fold increase in resistance to the hormone. This trait was stable in non-selective conditions for as long as was tested (200 days), but did not alter the response of the cells to water stress. Cell lines from the waterstress selection were not more resistant to mannitol than the parent line, and had a wide range of response to ABA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386409
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  • 12
    Electronic Resource
    Electronic Resource
    Polysomes from expanded tobacco leaves (1980)
    Springer
    Planta 148 (1980), S. 491-497 
    Details
    ISSN: 1432-2048
    Keywords: Leaves (polysomes) ; Nicotiana ; Polysomes ; Poly(A)+ RNA ; Protein synthesis ; RNA (polysomal, polyA+)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The isolation of intact polysomes from leaves of tobacco (Nicotiana tabacum L.) is dependent on the age and state of development of leaves. Undegraded polysomes from young leaves in the early stages of expansion can be isolated easily by extracting the leaves in ice-cold extraction buffer (200 mM tris(hydroxymethyl)aminomethylmethane(Tris)-HCl, pH 9.0; 400 mM KCl; 200 mM sucrose; 35 mM MgCl2). Medium-size leaves give best yields of undegraded polysomes when extractions are carried out in the above buffer and in the presence of ethyleneglycol-bis-(β-amino-ethyl ether)-N,N′-tetracetic acid (EGTA) and mercaptoethanol. Isolation of polysomes from large, nearly fully expanded (mature) leaves requires all of the above plus diethyldithiocarbamate (DIECA) in the extraction medium. An extraction medium consisting of 25 mM EGTA, 0.01 M mercaptoethanol, 25 mM DIECA and 0.5% of the nonionic detergent, Nonidet-P40 (NP 40) was found to be very suitable for extraction of polysomes from all developmental stages of leaves. The polysomes extracted in the above medium showed active translation of protein in the wheat-germ in-vitro protein-synthesizing system. The translational products were similar when translations were carried out directly with polysomes or polysomal RNA, or polysomal poly(A)+ RNA from tobacco leaves. Poly(A)− polysomal RNA was a poor template in the in-vitro wheat-germ system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00552665
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  • 13
    Electronic Resource
    Electronic Resource
    Comparison of proteins synthesized in vivo and in vitro by mRNA from isolated protoplasts (1980)
    Springer
    Planta 148 (1980), S. 453-454 
    Details
    ISSN: 1432-2048
    Keywords: mRNA ; Protein synthesis ; Protoplasts ; Nicotiana ; Translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Studies of proteins synthesized in vitro by messenger RNA (mRNA) extracted from tobacco protoplasts showed that the changes in protein synthesis and especially the lack of certain proteins observed previously in isolated protoplasts did not result from a failure of translation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02395314
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  • 14
    Electronic Resource
    Electronic Resource
    Influence of leaves and roots on meristem development inNicotiana tabacum L. cv. Wisconsin 38 (1980)
    Springer
    Planta 148 (1980), S. 462-467 
    Details
    ISSN: 1432-2048
    Keywords: Flower formation ; Leaves (in flower formation) ; Meristem (shoot) ; Nicotiana ; Roots (and flower formation)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The terminal, apical shoot meristem ofN. tabacum cv. Wisconsin 38 normally differentiates into a flower after producing 30 to 40 nodes. The influence of leaves and roots on the regulation of flowering was evaluated by counting the number of nodes produced after removal of leaves or the induction of adventitious roots. Leaf removal has no effect on the number of nodes produced before flower formation. Root induction significantly increases the number of nodes produced before flower formation. The plant behaves as if it were measuring the number of nodes between the meristem and the roots as a means of regulating meristem conversion from vegetative to floral differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02395316
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  • 15
    Electronic Resource
    Electronic Resource
    Auxin-binding by particulate fractions from tobacco leaf protoplasts (1980)
    Springer
    Planta 150 (1980), S. 9-12 
    Details
    ISSN: 1432-2048
    Keywords: Auxin binding ; Nicotiana ; Plasma membrane ; Protoplast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In vitro binding of 1-naphthaleneacetic acid (NAA) to particulate fractions from tobacco leaf protoplasts was studied. In freshly isolated protoplasts no specific binding could be detected, whereas it was present in particulate fractions from tobacco leaves. It is concluded that the NAA-binding-sites are probably located at the external face of the plasma membrane; they are destroyed during protoplast isolation by proteolytic enzymes in the cellulase and macerozyme preparations. After culturing the protoplasts for 3–4 d, the first cell divisions were observed and at the same time specific NAA-binding became detectable. The affinity constant for NAA was approx. 2·106 mol-1 and the number of binding sites increased during further culture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385607
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  • 16
    Electronic Resource
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    Fatty-acid composition and biosynthesis in cell suspension cultures of Glycine max (L.) Merr., Catharanthus roseus G. Don and Nicotiana tabacum L. (1980)
    Springer
    Planta 147 (1980), S. 384-388 
    Details
    ISSN: 1432-2048
    Keywords: Acetate incorporation ; Catharanthus ; Cell suspension cultures ; Fatty acids ; Glycihe ; Nicotiana ; Temperature and fatty-acid synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The fatty-acid composition of C. roseus and N. tabacum cell suspension cultures was unaffected by subculture on Wood and Braun, Murashige and Skoog, or Gamborg B5C media. However, placing the cultures — which were normally grown at 25° C — at 15° C reduced growth but resulted in enhanced formation of oleic and linolenic acids in C. roseus cultures and increased levels of linoleic and linolenic acids in cultures of G. max and N. tabacum, respectively. The incorporation of [14C]acetate into [14C]linoleic acid was more rapid in N. tabacum cells than in G. max cells, but was very poor in C. roseus where the [14C] label was distributed mainly between palmitic and oleic acids.
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    URL: http://dx.doi.org/10.1007/BF00380177
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  • 17
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    Expression of nuclear and chloroplastic genes coding for fraction-1 protein in somatic hybrids of Nicotiana tabacum + rustica (1980)
    Springer
    Planta 147 (1980), S. 414-417 
    Details
    ISSN: 1432-2048
    Keywords: Fraction-1 protein ; Hybrid, somatic ; Nicotiana ; Protein (Fraction 1) ; Ribulose-1,5-bisphosphate carboxylase ; Somatic hybrid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the sexual interspecific cross, Nicotiana rustica L.xN. tabacum L., N. rustica can serve as the female but not as the male parent. By fusion of protoplasts, the barrier to fertilization was overcome and somatic hybrids containing N. tabacum cytoplasm were produced as shown by isoelectric focusing of the Fraction-1 protein (F-1-protein). All somatic hybrids displayed polypeptides of the large subunit of F-1 protein (which is coded by the chloroplast genome) characteristic of only one or the other parental species. Two hybrids had large subunits of the N. tabacum type and two hybrids had those of the N. rustica type. Three hybrids contained three smallsubunit polypeptides (coded by the nuclear genome), one being characteristic of N. rustica, one characteristic of N. tabacum, and one with an isoelectric point common to both species. A fourth hybrid contained only two small-subunit polypeptides of the N. tabacum type but in a F-1 protein macromolecule whose large subunits were of the N. rustica type. One somatic hybrid was self-fertile and its F2 progeny contained large- and small-subunit polypeptides indistinguishable in their isoelectric points from those in the parent F1 hybrid. All somatic hybrids showed an aneuploid chromosome number and morphological characteristics intermediate between those of N. rustica and N. tabacum.
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    URL: http://dx.doi.org/10.1007/BF00380181
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  • 18
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    The effect of different temperatures on fatty-acid synthesis and polyunsaturation in cell suspension cultures (1980)
    Springer
    Planta 147 (1980), S. 389-395 
    Details
    ISSN: 1432-2048
    Keywords: Catharanthus ; Cell suspension cultures ; Glycine ; Fatty acids (synthesis, desaturation) ; Nicotiana ; Linoleic, linolenic, oleic, acids ; Temperature and fatty acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cell suspension cultures of Catharanthus roseus G. Don, Glycine max (L.) Merr. and Nicotiana tabacum L. were incubated with [14C]acetate, [14C]oleic acid and [14C]linoleic acid at five different temperatures ranging from 15 to 35° C. When the incubation temperature was increased, [14C]acetate was incorporated preferentially into [14C]palmitate, with a concomitant drop in [14C]oleate formation. Between 15 and 20° C, [14C]oleic acid accumulated in C. roseus cells. In all cultures, optimum desaturation of [14C]oleic acid to [14C]linoleic acid occurred between 20 and 25° C, and in G. max this was also the optimal range for desaturation of [14C]linoleic acid to [14C]linolenic acid. Elongation of [14C]palmitic acid was inhibited when cultures grown at 15° C for 25 h were subsequently incubated with [14C]acetate at 25° C. [14C]oleic acid accumulated in G. max and C. roseus cultures grown at 35° C for 25 h and subsequently incubated at 25° C. Desaturation of [14C]oleic acid increased up to 25° C, but then decreased or leveled off depending on the cell line and on the temperature prior to incubation.
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    URL: http://dx.doi.org/10.1007/BF00380178
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  • 19
    Electronic Resource
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    The role of peroxidase isoenzyme groups of Nicotiana tabacum in hydrogen peroxide formation (1980)
    Springer
    Planta 147 (1980), S. 467-470 
    Details
    ISSN: 1432-2048
    Keywords: Hydrogenperoxide ; Lignification ; Nicotiana ; Peroxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three peroxidase isoenzyme-groups found in cell walls of tobacco were tested for their capacity to form H2O2. Isoenzyme-group GI, located only in cell walls (GII and GIII are also found in protoplasts) showed the highest Kapp-value for H2O2-formation. The lowest Kapp-value, i.e., maximal H2O2-formation was received for group GIII which is ionically bound to the cell wall. As shown before, GI yields maximal polymerization rates for coniferyl- and p-coumarylalcohol. These facts indicate that each of the peroxidase isoenzyme groups of the cell wall is involved with different catalytic functions within the same pathways of H2O2-formation and succeeding lignification. H2O2-formation catalyzed by all 3 groups was increased by very low concentrations of Mn2+-ions. The required amount of Mn2+ leading to maximal stimulation was in each case dependent on the basic rate of H2O2-formation. Maximal stimulation of H2O2-formation by phenolic compounds was achieved by coniferylalcohol at a concentration of 10-4M for all groups. Stimulation by p-coumaryl-and by sinapylalcohol was not as significant.
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    URL: http://dx.doi.org/10.1007/BF00380189
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  • 20
    Electronic Resource
    Electronic Resource
    Comparison of proteins synthesized in vivo and in vitro by mRNA from isolated protoplasts (1980)
    Springer
    Planta 148 (1980), S. 453-454 
    Details
    ISSN: 1432-2048
    Keywords: mRNA ; Protein synthesis ; Protoplasts ; Nicotiana ; Translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Studies of proteins synthesized in vitro by messenger RNA (mRNA) extracted from tobacco protoplasts showed that the changes in protein synthesis and especially the lack of certain proteins observed previously in isolated protoplasts did not result from a failure of translation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00552659
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  • 21
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    Influence of leaves and roots on meristem development inNicotiana tabacum L. cv. Wisconsin 38 (1980)
    Springer
    Planta 148 (1980), S. 462-467 
    Details
    ISSN: 1432-2048
    Keywords: Flower formation ; Leaves (in flower formation) ; Meristem (shoot) ; Nicotiana ; Roots (and flower formation)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The terminal, apical shoot meristem ofN. tabacum cv. Wisconsin 38 normally differentiates into a flower after producing 30 to 40 nodes. The influence of leaves and roots on the regulation of flowering was evaluated by counting the number of nodes produced after removal of leaves or the induction of adventitious roots. Leaf removal has no effect on the number of nodes produced before flower formation. Root induction significantly increases the number of nodes produced before flower formation. The plant behaves as if it were measuring the number of nodes between the meristem and the roots as a means of regulating meristem conversion from vegetative to floral differentiation.
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    URL: http://dx.doi.org/10.1007/BF00552661
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    Characterization of a cytoplasmic auxin receptor from tobacco-pith callus (1980)
    Springer
    Planta 149 (1980), S. 44-47 
    Details
    ISSN: 1432-2048
    Keywords: Auxin receptor ; Callus ; Nicotiana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cultured tobacco-pith tissue contains a cytoplasmic receptor for indoleacetic acid (IAA). The concentration of binding sites is very low in comparison to that of several auxin receptors found by other investigators. A few obvious possible causes (degradation or inactivation) were investigated. From the results we conclude that the low number of binding sites is real. The receptor binds IAA optimally at pH 7.5–7.8 and at a temperature of 24–30°C, when incubated for 25–30 min. The binding is very specific, as is shown by competition experiments. The concentration of the receptor in the callus tissue changes dramatically during each culture period, which suggests a possible role in development. The receptor was partly purified by gel filtration on Sepharose 6B followed by ion-exchange chromatography on DEAE-cellulose.
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    URL: http://dx.doi.org/10.1007/BF00386225
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  • 23
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    A scanning electron microscopic investigation of in vitro osteogenesis (1980)
    Springer
    Calcified tissue international 30 (1980), S. 43-50 
    Details
    ISSN: 1432-0827
    Keywords: Osteogenesis ; In vitro ; Electron microscopy ; Mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Chick limb mesenchymal cells differentiate into muscle, cartilage, fibrous, and bone tissue. Previous reports show that when stage 24 limb mesenchymal cells are cultured in vitro, chondrocytes, myocytes, fibrocytes, and osteoblasts can be identified on the basis of morphological and biochemical parameters. The study reported here demonstrates that phenotypic expression in culture seems to be dependent on the initial plating density, Scanning electron microscopic observations indicate that when stage 24 limb mesenchymal cells are initially seeded at high densities (5 × 106 cells per 35 mm culture dish), mounds of cells appear in culture. These mounds represent cartilage nodules composed of a fine fibrous matrix and chondrocytes, surrounded by a loose fibrous connective tissue matrix. Cultures initially plated at intermediate densities (2.0–2.5 × 106 cells/35 mm culture dish) produce a flattened layer of fibrocytes overlying a matrix of collagen fibers and calcium phosphate deposits as determined by electron-microprobe analysis; these observations are indicative of osteoblast expression. Cells seeded at this intermediate density appear larger and possess greater surface area than cells seeded at high density. It is suggested that conditions that permit such increased cell surface area coupled with a relative compaction due to cell crowding may provide conditions permissive for osteogenesis. Based on morphological criteria, it appears that chick limb mesenchymal cell osteogenesis in vitro is not associated with chondrogenesis but represents a separate route of phenotypic expression.
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    URL: http://dx.doi.org/10.1007/BF02408605
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  • 24
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    Effects of demineralization in an ethanolic solution of triethylammonium EDTA on solubility of bone matrix components and on ultrastructural preservation (1980)
    Springer
    Calcified tissue international 32 (1980), S. 175-179 
    Details
    ISSN: 1432-0827
    Keywords: Decalcification ; Electron microscopy ; Bone matrix ; Bone glycoproteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A solution of triethylammonium EDTA in 80% ethanol was evaluated as a demineralizing reagent for bone in comparison with aqueous solutions of EDTA. Biochemical analysis and acrylamide gel electrophoresis of extracts of finely powdered bovine bone showed that most of the macromolecular components of the organic matrix extractable in aqueous EDTA were retained when the triethylammonium EDTA reagent was used. Ultrastructural examination of chick tibias decalcified with the reagents showed a better preservation of cellular morphology, especially the membranous components, and more uniformly distributed ground substance, though slightly less in quantity, when the aqueous reagent was used. Use of the two reagents appears to be complementary, the alkylammonium reagent being more appropriate for use in studies of the organic matrix of bone, including immunohistochemical studies of bone glycoproteins. The aqueous reagent is more appropriate for use in studies of cellular ultrastructure.
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    URL: http://dx.doi.org/10.1007/BF02408537
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  • 25
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    Fine structure of fetal rat calvarium; provisional identification of preosteoclasts (1980)
    Springer
    Calcified tissue international 31 (1980), S. 21-28 
    Details
    ISSN: 1432-0827
    Keywords: Rat ; Calvarium ; Electron microscopy ; Preosteoclasts ; Osteoclasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary This is a study of the fine structure of cells of the 20-day fetal rat calvarium. Special attention is given to identifying and characterizing preosteoclasts. These cells are relatively common and located largely, but not exclusively, at the endocranial bone surface. The preosteoclasts are characterized by abundant mitochondria, an incomplete perinuclear Golgi apparatus, and variable-shaped dense granules. The dense granules are unique in appearance in that they contain an internal dense matrix surrounded by a clear halo. Most granules are circular in shape but some are elongate or tubular in form. Granules with identical appearance are observed in osteoclasts. The preosteoclasts are mononucleate, or occasionally binucleate. It is suggested that because preosteoclasts are morphologically distinctive and relatively abundant, it should be feasible to separate these cells from a heterogeneous cell isolate.
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    URL: http://dx.doi.org/10.1007/BF02407163
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    Evidence for supercoiling in the DNA of bacteriophage heads (1980)
    Springer
    Archives of microbiology 126 (1980), S. 277-283 
    Details
    ISSN: 1432-072X
    Keywords: Bacteriophage ; Myxococcus ; λ ; Superooiled DNA ; Cross-linking ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract DNA was partially released from the heads of myxococcus phages and also coliphage λ and examined by electron microscopy by a modification of the Kleinschmidt technique, in which water was used as hypophase. DNA emerged from the heads in patterns suggestive of newly relaxed supercoils. The unreleased DNA appeared to occupy discrete regions in the head. Some closed circles were released from λ heads. When NaCl solution was used as hypophase, the DNA was observed either released from the tail or from the head, in the latter case, supercoiled regions were observed. When NH4OAc solution was used as hypophase, tightly wound structures were released from λ heads; these fields also contained supercoiled circles. The presence of constrained supercoiled domains in newly released phage DNA was confirmed by observing the effects of ethidium bromide on its conformation. Treatment of phage with nitrogen mustard, a bifunctional alkylating agent, preserved supercoiled domains, even when the phage were lysed over water as hypophase. Further experiments suggested that phage inactivation by nitrogen mustard is largely due to restraint of the supercoiled, native, tertiary structure and that DNA-protein cross-linking may be involved in this reaction. The implications of these findings for the conformation of phage DNA in vivo are discussed and a new model for the winding of DNA in phage heads is proposed.
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    URL: http://dx.doi.org/10.1007/BF00409932
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  • 27
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    The ultrastructure of cell wall formation and of gamma particles during encystment of Allomyces macrogynus zoospores (1980)
    Springer
    Archives of microbiology 128 (1980), S. 179-189 
    Details
    ISSN: 1432-072X
    Keywords: Allomyces ; Zoospores ; Cell wall ; Chitin ; Gamma particle ; Encystment ; Electron microscopy ; Calcofluor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Structural changes during cell wall formation by populations of semisynchronously germinating zoospores were studied in the water mold Allomyces macrogynus. Fluorescence microscopy using Calcofluor white ST (which binds to β-1,4-linked glycans) demonstrated that Calcofluor-specific material was deposited around most cells between 2–10 min after the induction of encystment (beginning when a wall-less zoospore retracts its flagellum and rounds up). During the first 15 min of encystment there was a progressive increase in fluorescence intensity. Ultrastructural analysis of encysting cells showed that within 2–10 min after the induction of encystment small vesicles 35–70 nm diameter were present near the spore surface, and some were in the process of fusing with the plasma membrane. The fusion of vesicles with the zoospore membrane was concomitant with the appearance of electron-opaque fibrillar material outside the plasma membrane. Vesicles similar to those near the spore surface were found within the gamma (γ) particles of encysting cells. These particles had a crystalline inclusion within the electron-opaque matrix. During the period of initial cyst cell wall formation numerous vesicles appeared to arise at the crystal-matrix interface. Approximately 15–20 min was required for the cell wall to be formed. We suggest that the initial response of the zoospore to induction of encystment is the formation of a cell wall mediated by the fusion of cytoplasmic vesicles with the plasma membrane.
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    URL: http://dx.doi.org/10.1007/BF00406156
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    Chemical composition and ultrastructure of cellular and extracellular Moraxella glucidolytica lipopolysaccharides (1980)
    Springer
    Archives of microbiology 128 (1980), S. 12-18 
    Details
    ISSN: 1432-072X
    Keywords: Moraxella glucidolytica ; Electron microscopy ; Lipopolysaccharide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cellular (LPS I) and extracellular (LPS II) lipopolysaccharide were isolated from Moraxella glucidolytica cells grown on ethanol and from the culture fluid, respectively. Both LPS were toxic when injected to mice and chick embryos. These LPS contained glucose, galactose, glucosamine, galactosamine, 2-keto-3-deoxyoctonate and lipids. By permethylation studies, glucose was found to be linked (1→6) and (1→3) in LPS I and only (1→6) in LPS II. Galactose was the terminal non-reducing sugar. Branching occurred at positions 3 and 4 of galactose residues. LPS I was rich in α- and β-hydroxylauric and α-hydroxymyristic acids and LPS II contained mainly stearic and α-hydroxymyristic acids. LPS I was detoxified by mild acid and alkaline treatments. It was also dissociated by sodium deoxycholate and chromatographed on Sephadex G-75. The main fraction was reassociated by removing the surfactant by dialysis. The morphology of LPS I and LPS II was examined by electron microscopy. LPS I (original and reassociated fractions) consisted exclusively of ribbons while LPS II contained ribbons and vesicles.
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    URL: http://dx.doi.org/10.1007/BF00422299
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  • 29
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    Ultrastructure of Ascodichaena rugosa on beech bark (1980)
    Springer
    Archives of microbiology 126 (1980), S. 87-95 
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    ISSN: 1432-072X
    Keywords: Ascodichaena ; Beech bark ; Electron microscopy ; Host-fungus relationship
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ascodichaena rugosa Butin is a corkinhabiting fungus, found frequently on the bark of Fagus sylvatica L. The hyphae of the fungus are distributed solely in the phellem cells, stopping their growth in the last-formed cork cell layer. The cell to cell invasion is effected by penetration hyphae, causing no extensive dissolution of the cork wall. Electron microscopical observations revealed fine structural details of the fruit bodies and of the intracellular hyphae. Of special interest were the finger-like hyaline hyphae in the last-formed layer of cork cells, which are interpreted as haustoria on the basis of the fine structure both of hyphae and host cells. This situation is considered as reflecting a parasitic relationship of Ascodichaena to beech bark. The activity of the fungus led also to the increased production of cork cells, perhaps related to the nutrient supply of the fungus.
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    URL: http://dx.doi.org/10.1007/BF00421896
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    Immunoferritin labeling of respiratory nitrate reductase in membrane vesicles of Bacillus licheniformis and Klebsiella aerogenes (1980)
    Springer
    Archives of microbiology 127 (1980), S. 39-46 
    Details
    ISSN: 1432-072X
    Keywords: Immunoferritin labeling ; Electron microscopy ; Membrane vesicles ; Nitrate reductase ; Bacillus licheniformis ; Klebsiella aerogenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The indirect immunoferritin labeling method was used to localize the membrane-bound respiratory nitrate reductase in membrane vesicles and protoplasts or spheroplasts of Bacillus licheniformis and Klebsiella aerogenes, respectively. For a comparison of the labeling of the various vesicle preparations, which differed not only in size but also in the percentage of inside-out orientation, a quantification of the results was needed to circumvent the problem of non-specifically bound ferritin. From the results the sidedness of the nitrate reductase in the cytoplasmic membrane of the abovementioned bacteria was determined as being cytoplasmic in B. licheniformis and as transmembranous in K. aerogenes.
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    Restoration of fertility in cytoplasmic male sterile (CMS) Nicotiana Sylvestris by fusion with X-irradiated N. tabacum protoplasts (1980)
    Springer
    Theoretical and applied genetics 58 (1980), S. 121-127 
    Details
    ISSN: 1432-2242
    Keywords: Nicotiana ; Cytoplasmic-male-sterility ; Somatic hybridization ; Plastid segregation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Restoration of male fertility was achieved by fusing protoplasts from male sterile (CMS) Nicotiana sylvestris plants with X-irradiated protoplasts derived from fertile N. tabacum plants. The CMS N. sylvestris plants were derived from a previous somatic hybridization experiment and contained alien (Line 92) cytoplasm. About one quarter of the regenerated plants were found to be cybrids. i.e. they consisted of N. sylvestris nuclei combined with all or some components of N. tabacum cytoplasm. In one half of these cybrids male fertility was restored to different levels. The chloroplasts of the two parental donors differ in respect to tentoxin sensitivity: chloroplasts of CMS N. sylvestris are sensitive while those of N. tabacum are insensitive. It could therefore be demonstrated that there was an independent segregation of chloroplast type and male fertility/sterility: several somatic cybrids were male fertile but tentoxin sensitive and others were tentoxin insensitive yet they were male sterile. Only in about one half of the somatic cybrids was male fertility restored together with restoration to tentoxin insensitivity.
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    URL: http://dx.doi.org/10.1007/BF00263102
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    Factors influencing the incidence of habituation for cytokinin of tobacco pith tissue in culture (1980)
    Springer
    Planta 150 (1980), S. 264-268 
    Details
    ISSN: 1432-2048
    Keywords: Cytokinin habituation ; Habituation, cytokinin ; Nicotiana ; Position effects (habituation) ; Size effects (habituation) ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pith tissue of Nicotiana tabacum L. cv. “Havana 425” exhibits a gradient in its tendency to habituate for cytokinin on an auxin-containing medium at 35° C, about 10° C above the standard culture temperature. Explants of pith from below the 8th to 11th internode, counting from the bottom of the plant, rarely habituate for cytokinin; explants from above this threshold habituate rapidly. The explants must also be above a critical size, about 20–30 mg, to habituate. There was a pronounced interaction between size and position effects; the threshold position for cytokinin habituation shifted upward with decreasing explant size.
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    URL: http://dx.doi.org/10.1007/BF00390836
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    The induction of cytokinin habituation in primary pith explants of tobacco (1980)
    Springer
    Planta 149 (1980), S. 402-407 
    Details
    ISSN: 1432-2048
    Keywords: Cytokinin ; Habituation rates ; Nicotiana ; Temperature and habituation ; Tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pith parenchyma tissue ofNicotiana tabacum L. cv. “Havana 425” becomes cytokinin habituated when incubated at 35°C on an auxin-containing medium. Under these conditions, habituated, hyperplastic nodules appear on the tissues. We used these nodules to estimate the incidence of habituation by a statistical method. The rate of habituation varied with the season. Tissue isolated from plants in the spring habituated approx. 7 times faster than did tissue isolated from plants in winter. The fact that the average rate, 〉4×10−3 per cell generation, was 100–1,000 times faster than the rate of somatic mutation inNicotiana species and depended on the physiological state of the tissue provides further evidence that habituation involves epigenetic changes rather than rare, random genetic mutations. We also found that kinetin (6-furfurylaminopurine) induced habituation and that the concentration required depended on the duration of cytokinin treatment. For long incubation times, approx. 6×10−10 M kinetin, which is about 1,000-fold lower than the concentration optimal for growth of cytokinin-requiring pith tissue, was sufficient to induce habituation. These results support the hypothesis that the habituated state is maintained by a positive feedback loop in which cytokinins either induce their own synthesis or inhibit their own degradation.
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  • 34
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    Selection of embryogenic pollen from cold-treated buds ofNicotiana tabacum var. badischer burley and their development into embryos in cultures (1980)
    Springer
    Protoplasma 105 (1980), S. 161-167 
    Details
    ISSN: 1615-6102
    Keywords: Embryogenic pollen ; Nicotiana ; Pollen culture ; Selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary By using density gradient centrifugation, employing 55% percoll and 4% sucrose as suspension medium, it is possible to select embryogenic pollen from buds after cold treatment at 10 °C for 8 or more days. These buds at the uninucleate stage of pollen were collected from plants grown in 8 hours photocycles at 18 °C and supplied with mineral salts. The embryogenic pollen are small, starch-free with a clear cytoplasm whereas large starch-filled ones are nonembryogenic. The embryogenic pollen regularly form embryos at a frequency of 2% on a mineral medium supplemented with glutamine, asparagine and sucrose at pH 6.5. These results demonstrate, for the first time, that it is possible to have embryos in appreciable frequencies in “ab initio” pollen cultures raised from cold treated anthers.
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    URL: http://dx.doi.org/10.1007/BF01279858
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    Ultrastructural changes in Paneth cells during hibernation in the ground squirrel Spermophilm lateralis (1980)
    Springer
    Cell & tissue research 211 (1980), S. 293-301 
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    ISSN: 1432-0878
    Keywords: Paneth cell ; Hibernation ; Intestine ; Hypothermia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Paneth cells from jejuno-ileal segments of the small intestine of the ground squirrel, S. lateralis, was examined under normal euthermic conditions and during the profoundly depressed metabolic conditions of natural hibernation. Paneth cells obtained from hibernating animals gave evidence of markedly reduced activity when compared to Paneth cells from euthermic animals. In hibernating animals, the nuclei were smaller, with less prominent nucleoli and with an increased proportion of heterochromatin. In hibernating animals, the rough endoplasmic reticulum was fragmentary and poorly organized, in contrast to the typical arrangement of concentric lamellae seen in euthermic animals. Although the total number of ribosomes was decreased in hibernating animals, there were proportionally more free ribosomes than in euthermic animals. Paneth cells from hibernating animals also contained a greater number of apical secretory granules which were smaller and more variable in electron density than granules from control animals. These ultrastructural features indicate that during hibernation the Paneth cell is relatively quiescent.
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    Microtubules, dendritic spines and spine apparatuses (1980)
    Springer
    Cell & tissue research 208 (1980), S. 171-181 
    Details
    ISSN: 1432-0878
    Keywords: Microtubules ; Dendritic spine apparatus ; Synapse ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using techniques for enhanced microtubular preservation, including albumin pretreatment (Gray, 1975), occipital cortex of rats was studied electron microscopically at various ages of development. A close structural relationship was seen between microtubules, sacs of SER and the postsynaptic “thickening” in primordial spines and with the dense “plate” material of spine apparatuses. Stereoscopic preparations in addition show a more complicated substructure than previously described for the “plate”. Microtubules may contribute to the formation of the “plate” of the spine apparatus which in turn is associated with the postsynaptic “thickening” of the mature spine. Possible functional correlates are discussed.
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    Lactate sensitive cells in newt kidneys (1980)
    Springer
    Cell & tissue research 207 (1980), S. 233-239 
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    ISSN: 1432-0878
    Keywords: Kidney ; Triturus cristatus carnifex ; Erythropoiesis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Specimens of Triturus cristatus carnifex (Laurenti), raised in 3.2 g/l solution of sodium lactate, presented hypertrophy of “lactate sensitive cells” (LSC) clustered at the vascular pole of each renal corpuscle. As seen under both the light and electron microscopes, these are specialized cells of the Bowman's capsule located at the junction between its visceral and parietal layers. The structure formed by the cells, heretofore unknown, is topographically associated with the juxtaglomerular apparatus. As lactate stimulates erythropoiesis even in normal oxygenated specimens and hypoxia induces hypertrophy of LSC in newts, it is hypothesized that the LSC are the site of erythropoietin (ESF) synthesis. A scheme of ESF biogenesis in newts, integrating the above principles, concludes the paper.
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    Ontogeny and organization of the stationary non-lymphoid cells in the human thymus (1980)
    Springer
    Cell & tissue research 207 (1980), S. 287-306 
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    ISSN: 1432-0878
    Keywords: Fetal human thymus ; Epithelial cells ; Development and differentiation ; Mesenchymal reticulum cells ; T lymphocytes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ontogenetic differentiation of the human thymus was investigated in 50 embryos by means of light and electron microscopic methods in an attempt to clarify the morphogenesis of the complicated microecology of thymic tissue. At the 8th gestational week (g.w.), the primordium of the thymus contains almost exclusively undifferentiated epithelial cells. At the 10th g.w., the epithelial cells in the central part are spindle-shaped. During the subsequent weeks the cortical region of the thymus becomes separated into lobes by mesenchymal septa containing hemopoietic precursor cells and large electronlucent cells with irregularly shaped nuclei. The latter cells are also found in the deeper presumptive medullary regions of the thymus; they differentiate into interdigitating reticulum cells (IDC). The permeation of the medulla of the thymus by non-epithelial IDC occurs concurrently with the formation of cortical and medullary epithelial cells. Between the 12th and 14th g.w. the cortical and medullary differentiation is completed. At this time-stage cortical small lymphocytes differ in morphological shape from medullary lymphocytes, the latter acquiring the appearance of immunocompetent T cells and establishing intimate contact with the IDC. These findings indicate that the thymic cortex and medulla contain different epithelial cells. In addition, the thymic medulla displays cells characterized by the morphology of typical interdigitating reticulum cells of peripheral lymphoid tissue. The structural pattern of the thymus is correlated to morphologically differing lymphoid cell populations in the cortical and medullary regions.
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    Scanning and transmission electron microscopic study of the supraependymal macrophages in the lateral ventricles of the toad brain (1980)
    Springer
    Cell & tissue research 207 (1980), S. 321-329 
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    ISSN: 1432-0878
    Keywords: Supraependymal cells ; Macrophages ; Electron microscopy ; Lateral ventricles ; Amphibian brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Transmission and scanning electron microscopy of the lateral ventricles of the toad brain revealed the presence of supraependymal cells that have the features of macrophages. Based solely on their surface morphology three different cell forms could be identified. The most frequently observed cells are flat and multipolar, and have a smooth or ruffled surface. The second type is spherical with a ruffled surface and occurs either singly, in which case it lacks processes, or in clusters from which processes radiate. The third type has surface blebs and numerous thin, smooth processes. However, when specimens that had been examined in the scanning electron microscope are viewed in the transmission electron microscope, all cells appear to belong to a single cell type. All cells viewed closely resemble macrophages in that they contain nuclei with clumped chromaffin, single cisternae of rough endoplasmic reticulum, numerous dense bodies, and many Golgi complexes. In addition, when horseradish peroxidase (HRP) was perfused into the ventricles, reaction product was found a short time thereafter within cytoplasmic vacuoles, and after a longer period within dense bodies. Because of their ultrastructural resemblance to macrophages and their capacity to ingest HRP, we suggest that these cells function as phagocytes and, as such, act to remove foreign materials from the cerebrospinal fluid.
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    The tight junctions of renal tubules in the cortex and outer medulla (1980)
    Springer
    Cell & tissue research 212 (1980), S. 395-413 
    Details
    ISSN: 1432-0878
    Keywords: Kidney ; Distal tubule ; Collecting duct ; Electron microscopy ; Thin sections ; Freeze fracturing ; Tight junctions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Quantitative aspects of tight junction morphology were systematically studied in the cortical and outer medullary segments of the distal urinary tubules of rat, hamster, rabbit, cat, dog and the primitve primate Tupaia belangeri. Only minor differences in junctional architecture were found between straight and convoluted portions of the distal tubule. In contrast, the collecting duct in cortex and outer medulla, in all species, exhibits the most elaborate tight junctions observed along the uriniferous tubule. The present and previous findings from this laboratory indicate that increasing “tightness” of the junctional complexes is apparent along the course of the nephron in all species studied. The proposed relationship between quantitative aspects of the zonula occludens and presently available values for transepithelial electrical resistance was re-examined for the renal tubules. It was found that for the mammalian kidney a satisfactory correlation exists between the tight junction morphology and presently known functional parameters. This relationship is the more evident the more additional dimensional characteristics of the intercellular clefts are taken into consideration. It may therefore be concluded that, at least for the mammalian kidney, the assumption of differences in the molecular organization of the tight junctions is not needed to explain so far unresolved discrepancies between tubular morphology and function.
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    URL: http://dx.doi.org/10.1007/BF00236506
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    An electron microscopic study on stellate cells in the rabbit adenohypophysis under various endocrine conditions (1980)
    Springer
    Cell & tissue research 213 (1980), S. 237-246 
    Details
    ISSN: 1432-0878
    Keywords: Stellate cell ; Nongranulated cell ; Adenohypophysis ; Rabbit ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Stellate cells in the rabbit adenohypophysis were observed electron microscopically under normal and experimental conditions such as lactation, thyroidectomy, adrenalectomy, or castration. In control animals stellate cells had a scanty cytoplasm surrounding the nucleus and possessed slender processes extending between granulated cells. The processes were interconnected by desmosomes to form a meshwork. In the cytoplasm, abundant microfilaments were present as well as ill-developed ordinary cell organelles, but secretory granules were absent. In the adenohypophysis of experimental groups, in which the granulated cells underwent characteristic changes, stellate cells also showed remarkable morphological alterations which were similar in all groups. In general, they became hypertrophied, and contained a well-developed Golgi apparatus and rough-surfaced endoplasmic reticulum. Lysosomes or lipid droplets were frequently encountered. Between adjacent stellate cells, intercellular canals were markedly developed and many microvilli were noticed. Based on the above data, it is suggested that the stellate cells are not only sustentacular elements, but play an important role in the function of the adenohypophysis, such as the supply of materials to granulated cells or the disposal of waste products.
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    URL: http://dx.doi.org/10.1007/BF00234784
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    The programming of silk-gland development in Bombyx mori (1980)
    Springer
    Cell & tissue research 213 (1980), S. 311-324 
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    ISSN: 1432-0878
    Keywords: Bombyx ; Silk-gland ; Starvation ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cytological development of the silk gland has been studied by light and electron microscopy in silkworms experimentally starved at different periods of the natural feeding stage during the fifth instar. When newly molted animals are not provided with food, no sign of growth is observed. Starvation initiated early during the obligatory feeding period, stops cell growth and development of the organelles involved in protein synthesis and secretion, whereas it induces the appearance of organelles concerned with autolysis. These effects are reversible if starvation is not prolonged beyond two days. Starvation during the facultative feeding period, at the time of massive fibroin production, results in quantitative and qualitative modifications of organelles related to the decrease of fibroin production and the onset of autolysis. Rough endoplasmic reticulum, responsible for fibroin synthesis, forms transitory whorls. Fibroin transport via the Golgi apparatus and secretion of the protein into the gland lumen decrease parallel to fibroin synthesis, so that no fibroin storage can be detected in any organelle. After food deprivation, autophagosomes and secondary lysosomes rapidly develop in the cytoplasm, and if starvation continues portions of the cytoplasm are sequestered and completely destroyed. If animals are refed, fibroin production is resumed and autolysis declines. These ultrastructural alterations of the silk gland during experimental starvation are very similar to those observed during the periods of physiological starvation (molt and cocoon spinning) and generally considered to be under hormonal control. Our results raise the question of the nature of interactions between alimentary and hormonal factors which control silk-gland development.
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    Babesia microti (Apicomplexa: Piroplasmida): Electron microscope detection in salivary glands of the tick vectorIxodes ricinus (Ixodoidea: Ixodidae) (1980)
    Springer
    Parasitology research 64 (1980), S. 113-115 
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    ISSN: 1432-1955
    Keywords: Babesia microti ; Electron microscopy ; Ticks ; Ixodes ricinus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00927061
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    Some observations onHaemohormidium cotti Henry 1910, from the marine fishCottus bubalis euphrasen (1980)
    Springer
    Parasitology research 62 (1980), S. 31-38 
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    ISSN: 1432-1955
    Keywords: Haemohormidium cotti ; Light microscopy ; Electron microscopy ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Haemohormidium cotti, an organism of uncertain status, is redescribed from one of its type hosts, the marine fish,Cottus bubalis. The parasite occurs as irregularly round, oval, or elongate, intraerythrocytic bodies within blood and tissue preparations. Electron micrographs show features which suggest thatH. cotti may, as previously suspected, belong with the Piroplasmasida but no firm evidence of this is established. Possible division stages are identified in both light and electron micrographs. The taxonomic position ofHaemohormidium is discussed.
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    Pancreatic polypeptide (PP)- and glucagon cells in the pancreatic islet of Xiphophorus helleri h. (Teleostei) (1980)
    Springer
    Cell & tissue research 205 (1980), S. 187-198 
    Details
    ISSN: 1432-0878
    Keywords: Pancreatic polypeptide (PP) ; Glucagon ; Pancreatic islet ; Xiphophorus helleri ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'étude immunohistochimique de l'îlot pancréatique du poisson téléostéen Xiphophorus helleri, à l'aide de sérums anti-polypeptide pancréatique (PP) et anti-glucagon a permis de montrer que deux populations cellulaires distinctes sont responsables de la sécrétion de ces hormones. L'observation comparée de coupes sériées, ultrafines et semifines, traitées par la technique immunohistochimique, a démontré que les cellules à PP correspondent aux cellules qui avaient été précédemment définies, dans cette espèce, comme “cellules A2 à grains ronds” et que les cellules sécrétrices de glucagon sont les “cellules A2 à grains cristallins”. L'hypothèse de l'existence de deux catégories de cellules à glucagon chez les téléostéens est abandonnée.
    Notes: Summary Correlative immunohistochemical and electron microscopical studies on the pancreatic islet of the teleost fish Xiphophorus helleri using antibodies to pancreatic polypeptide (PP) and glucagon show that separate cell types are responsible for the production of these peptides. The PP-cells correspond to the previously described “A2-cells with round granules”, while the “A2-cells with crystalline granules” are the true glucagon cells. An earlier suggestion that there are two types of glucagon cells in teleost islets is therefore withdrawn.
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    Organ culture of the islets of Langerhans from young and senescent rats (1980)
    Springer
    Cell & tissue research 207 (1980), S. 429-448 
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    ISSN: 1432-0878
    Keywords: Islet of Langerhans ; Aging ; Insulin-secreting cells ; Organ culture ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The B-cells of the endocrine pancreas constitute an adequate model for in vitro study of the aging process in highly differentiated cells. In the present study, collagenase-isolated islets of Langerhans from young and senescent rats were cultured up to 28 days. The response of the B-cells to the stimulatory conditions of the culture medium involved the nucleus, ribosomes, endoplasmic reticulum, Golgi apparatus, and secretory granules. Correlated data from light microscopy, electron microscopy, and insulin radioimmunoassay show that the differentiation and function of senescent B-cells are maintained in culture, as it has been proven for the B-cells of younger animals. On the other hand, signs of cytological deficiency not directly concerned with the specific function of B-cells were observed: abnormal mitochondria and lysosomes are more numerous in the senescent B-cells. The proliferative capacity of the B-cells of aged rats is reduced.
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    URL: http://dx.doi.org/10.1007/BF00224618
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    An electron microscopic study of the salivary gland of Rhynchosciara angelae (1980)
    Springer
    Cell & tissue research 207 (1980), S. 449-461 
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    ISSN: 1432-0878
    Keywords: Rhynchosciara angelae ; Salivary gland ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the salivary gland of the dipteran insect Rhynchosciara angelae in a defined stage of the larval development, characterized by the synthesis and storage of secretion product, is described. Observations were made with both Nomarski optics and electron microscopy. Filiform projections extending into the lumen of the gland were observed in the apical portion of the cells. At the basal region junctions, characterized as hemidesmosomes, were observed between the membrane of the cell and the basal lamina. The plasma membrane presents numerous infoldings into the cell increasing considerably the surface area at this region. Throughout the cytoplasm of the gland cells numerous mitochondria, Golgi complexes, microtubules, profiles of endoplasmic reticulum, secretion granules and glycogen granules were observed. Carbohydrates were detected on ultrathin sections by using the periodic acid-silver methenamine and the periodic acid-thiosemicarbazide-silver proteinate techniques.
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    URL: http://dx.doi.org/10.1007/BF00224619
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    Fibre types in the locomotory muscles of an antarctic teleost, Notothenia rossii (1980)
    Springer
    Cell & tissue research 208 (1980), S. 143-164 
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    ISSN: 1432-0878
    Keywords: Locomotory muscle ; Fibre types ; Antarctic fish (Notothenia rossii) ; Histochemistry ; Electron microscopy ; Energy metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The metabolic and structural differentiation of locomotory muscles of Notothenia rossii has been investigated. In this species sustained locomotion is achieved by sculling with enlarged pectoral fins (labriform locomotion), whilst the segmental myotomal muscle is reserved for burst activity. Red, white and subepidermal fibres can be distinguished in the trunk by histochemical and ultrastructural criteria. The main pectoral muscle (m. adductor profundus) consists entirely of red fibres. These three main fibres types show differences in histochemical staining profiles, capillarization, myofibril shape and packing, and lipid and mitochondrial content. The fractional volume of mitochondria amounts to 38% for pectoral, 30% for red myotomal and 1.9% for white myotomal fibres. Enzyme activities of red pectoral muscle are consistent with a higher potential for aerobic glucose and fatty acid oxidation than for the red myotomal fibres. Mg2+ Ca2+ -myofibrillar ATPase activities are similar for red pectoral and myotomal muscles and approximately half of those white fibres. Specialisations of N. rossii muscles associated with labriform swimming and locomotion at Antarctic temperatures are discussed.
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    URL: http://dx.doi.org/10.1007/BF00234180
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    The fine structure of the stomach mucosa of the llama (Llama guanacoe) (1980)
    Springer
    Cell & tissue research 208 (1980), S. 207-228 
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    ISSN: 1432-0878
    Keywords: Hind stomach ; Fundic glands ; Electron microscopy ; Histochemistry ; Endocrine cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithelium of the fundic region mucosa of the hind stomach in the Llama guanacoe has been studied using morphological and histochemical methods. Morphology suggests that solute and water absorption may occur in the epithelium of the surface and of the foveolae, although this absorption can not be estimated because of the extensive secretion of the gastric glands. The same cells of the surface and foveolar epithelium show numerous secretory granules. The glands reveal neck cells, chief cells, a large number of oxyntic cells, four types of endocrine cells (A-like, ECL, D and EC), brush cells and wandering cells. PAS and Alcian blue reactions for light microscopy suggest a secretion of neutral and acidic mucosubstances in the surface and foveolar epithelium, of neutral mucosubstances only in the neck cells. Periodic acid-thiocarbohydrazide silver proteinate (PA-TCH-SP) reaction for electron microscopy confirms the presence of neutral mucosubstances within the secretory granules of the surface, foveolar and neck epithelial cells. In all these cells, the reaction product is also evident within sacculi and vesicles of the maturing surface of the Golgi apparatus. A positive PA-TCH-SP reaction also occurs on the membrane (and not on the contents) of the Golgi apparatus (maturing surface) and of the secretory granules of the chief cells as well as on the membrane of the Golgi apparatus and of apical vesicles and tubules of the oxyntic cells. In addition, silver granules slightly enhance the electron density of the contents of the secretory granules in the endocrine cells. Morphological and histochemical findings are discussed and compared with results described by others for monogastric mammals.
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    The synaptic organization of visual interneurons in the lobula complex of flies (1980)
    Springer
    Cell & tissue research 208 (1980), S. 371-387 
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    ISSN: 1432-0878
    Keywords: Lobula complex ; Visual interneurons ; Ultrastructure ; Cobalt-impregnations ; Electron microscopy ; Diptera (Calliphora erythrocephala)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The synaptic organization of three classes of cobalt-filled and silver-intensified visual interneurons in the lobula complex of the blowfly Calliphora (Col A cells, horizontal cells and vertical cells) was studied electron microscopically. The Col A cells are regularly spaced, columnar, small field neurons of the lobula, which constitute a plexus of arborizations at the posterior surface of the neuropil and the axons of which terminate in the ventrolateral protocerebrum. They show postsynaptic specializations in the distal layer of their lobula-arborizations and additional presynaptic sites in a more proximal layer; their axon terminals are presynaptic to large descending neurons projecting into the thoracic ganglion. The horizontal and vertical cells are giant tangential neurons, the arborizations of which cover the anterior and posterior surface of the lobula plate, respectively, and which terminate in the perioesophageal region of the protocerebrum. Both classes of these giant neurons were found to be postsynaptic in the lobula plate and pre- and postsynaptic at their axon terminals and axon collaterals. The significance of these findings with respect to the functional properties of the neurons investigated is discussed.
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    Lipid droplets in the visceral yolk sac endodermal cells of the postimplantation rat embryo: Application of malachite green-glutaraldehyde fixative (1980)
    Springer
    Cell & tissue research 209 (1980), S. 29-41 
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    ISSN: 1432-0878
    Keywords: Visceral yolk sac ; Lipid droplets ; Malachite green-glutaraldehyde fixative ; Rat embryo ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the visceral yolk sac (VYS) of the rat embryo at day 9.5 of gestation was examined after fixation with either Karnovsky's glutaraldehyde-paraformaldehyde solution or malachite green-containing glutaraldehyde (MGA) solution. Fixation with MGA retained homogeneously electron-dense droplets in the cytoplasm and the nucleus of endodermal cells, both of which were lost in the specimens prepared by Karnovsky's fixation method. The cytoplasmic MGA-positive droplets were frequently associated with other cytoplasmic organelles such as rough endoplasmic reticulum, mitochondria and membrane-delineated inclusion bodies, but these cytoplasmic organelles never incorporated MGA-positive materials, whereas Golgi apparatus contained intracisternal MGA-positive droplets. Extracellular MGA-positive droplets were also encountered at the apical surface of endodermal cells and in the intercellular space between endodermal cells and the underlying mesodermal cells. These MGA-positive droplets were considered to be lipid in nature, and their origin in the endodermal cells of VYS is discussed.
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    Dense material associated with apparent presynaptic elements in cell cultures of the CNS (1980)
    Springer
    Cell & tissue research 211 (1980), S. 95-103 
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    ISSN: 1432-0878
    Keywords: Synapse ; Synaptogenesis ; Cell culture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In cell cultures of the rat cerebellum, electron-dense material has been found occasionally between adjacent cells. More often than not, presynaptic elements on one side of the dense material faced either neuronal or nonneuronal cells on the other side. The 20 nm thick material was stained either with the osmium-uranyl-lead (OsUL) procedure or with the ethanolic phosphotungstic acid (E-PTA) procedure. To determine the source of the dense material, various compounds were added to cultures at 7 days in vitro. Only a crude nuclear fraction was able to duplicate the appearance of the dense material associated with the apparent presynaptic elements. It was concluded that apparent presynaptic elements were associated with the polybasic dense material and that this type of association may duplicate an interaction in the normal development of synaptic contacts.
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    Ca++-induced structural changes in photoreceptor microvilli of diptera (1980)
    Springer
    Cell & tissue research 206 (1980), S. 225-232 
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    ISSN: 1432-0878
    Keywords: Compound eye ; Photoreceptor membrane ; Electron microscopy ; Calcium-induced changes ; Artefacts ; Diptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When the compound eyes of the fly Lucilia are fixed for electron microscopy with glutaraldehyde in common buffer solutions, artefactual whorls are liable to be formed from the photoreceptor microvilli. The whorls result from two factors: (i) a prolonged time interval prior to osmication, such as the “overnight” primary fixation or wash at 4° C commonly used in studies of compound eyes; (ii) as little as 1–2 mM Ca++ in the primary fixative and wash solutions. Osmication after short (1 h) glutaraldehyde fixation at 4° C, or omission of Ca++ and addition of 2 mM EGTA, prevent whorl-formation. In the tipulid fly Ptilogyna, similar artefacts are produced, but are confined to the distal zone of the microvilli that sheds during turnover.
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    Fine structure of ependymal cysts in and around the area postrema of the rat (1980)
    Springer
    Cell & tissue research 206 (1980), S. 303-318 
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    ISSN: 1432-0878
    Keywords: Area postrema, rat ; Ependyma ; Cyst ; Circumventricular organs ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Peculiar cells forming cysts were observed in the area postrema and sometimes also in the choroid plexus and the tela chorioidea near the area postrema, and were studied in detail by electron microscopy. The cytological features of the cyst cell and its junctional relationship to neighboring cells imply that cyst cells are derived from ependymal and choroid epithelial cells. The cyst cells usually contact directly the perivascular spaces of postremal, choroidal or pial capillaries, where the cytoplasm is often considerably attenuated. The cystic lumen is commonly filled with a flocculent material. The limiting membrane of the cystic lumen, which frequently bears cilia and microvilli, has the same thickness as the surface cell membrane. In many cases, the cyst is surrounded by the cytoplasm of a single cell. In some cases, however, two cells participate in the formation of the cyst, although one is only a slender process and joined by a zonula occludens with the main cyst cell. Horseradish peroxidase (HRP) injected into the cerebrospinal fluid (CSF) space failed to enter the cystic lumen. A possible significance of the cyst in relation to the CSF and blood circulation was considered.
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    Ultrastructural alterations of the pancreatic D cell in the domestic fowl following vagotomy (1980)
    Springer
    Cell & tissue research 211 (1980), S. 171-174 
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    ISSN: 1432-0878
    Keywords: Pancreatic D cell ; Neural control ; Vagotomy ; Electron microscopy ; Fowl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an attempt to determine the neural control of pancreatic D cells, the pancreatic islets of the domestic fowl were examined electron microscopically from 1 to 28 days after abdominal vagotomy. Exocytotic release of many secretory granules from D cells occurred one day after vagotomy. Rough endoplasmic reticulum developed and formed an arrangement of concentric whorls in the cytoplasm of D cells after axotomy. The altered D cells were also characterized by the occurrence of many peculiar dense bodies in the apical cytoplasm at all time periods studied. These bodies varied in shape and size, containing several round vesicles. The D cells were extensively depleted of granules after the longer time periods following vagotomy. The present results provide new morphological evidence for the vagus-nerve control of D cells, which may regulate the activity of islet cells.
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    Fetal hypothalamic transplants in the third ventricle of the adult rat brain (1980)
    Springer
    Cell & tissue research 211 (1980), S. 191-206 
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    ISSN: 1432-0878
    Keywords: Hypothalamus ; Transplants ; Vasopressin ; Median eminence ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Blocks of anterior hypothalamus were transplanted from 19 day-old fetuses of Wistar/Lewis rats into the third ventricle of adult male Brattleboro rats. Physiological changes in graft recipients and in sham-operated animals were monitored daily. Twenty days after surgery, the graft recipients and shamoperated animals were killed and their brains examined by correlative scanning and transmission electron microscopy. Host animals that exhibited both decreased polydipsia and increased urine concentration were found to have viable grafts within the third ventricle. The observed physiological changes suggested that synthesis and release of vasopressin occurred in the transplanted neurons. Grafts were well vascularized by vessels arising from the host hypothalamus. Neurons, with perikarya ranging from 8 to 30 μm in diameter, glial cells, and neurites were located throughout the transplants. A neurohemal contact zone, similar to that normally seen in the median eminence, could not be demonstrated in the grafts. The absence of complete glial and ependymal barriers indicates a relatively close association between cells in the transplants and the cerebrospinal fluid. A large increase in supraependymal neurons and their processes, including an eruption of neurons through the floor of the third ventricle in one animal, was observed in graft recipients but not in shamoperated animals.
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    Electron microscopic study of the paracortical postcapillary “high endothelial venules” in lymph nodes of the normal calf (1980)
    Springer
    Cell & tissue research 212 (1980), S. 465-474 
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    ISSN: 1432-0878
    Keywords: Postcapillary venules ; Calf ; Lymph nodes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the postcapillary “high endothelial venules” (HEV) of lymph nodes in calves was studied light and electron microscopically. These venules were detected light microscopically in the paracortical zone by their high cuboidal endothelium, a distinct basal lamina, the migration of lymphocytes through the vessel wall, and the dominance of lymphoid cells in the lumen, often completely obliterating the latter. Ultrastructurally, the endothelial cells (HEC) of the HEV were characterized by a prominent Golgi complex including many small vesicles, a few lysosome-like bodies, and a specific association between mitochondria and rough endoplasmic reticulum (MER). The HEC are connected by desmosomes, whereas the intimate contact points between migrating lymphocytes and endothelial cells could not be classified according to the well-defined junctional types. Lymphocyte migration occurred predominantly intercellularly, i.e., between endothelial cells. Although the overall appearance of the described vessel type in bovines bears resemblance to HEV in other investigated species, several differences occur that most probably are related to species variation.
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    Incorporation of 3H-oleic acid by the proximal convoluted tubule cells of the chick (Gallus domesticus) (1980)
    Springer
    Cell & tissue research 210 (1980), S. 447-459 
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    ISSN: 1432-0878
    Keywords: Lipid ; Kidney tubules, proximal ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Lipid metabolism in the cells of the renal proximal convoluted tubules (PCT) was investigated in healthy fowls and in fowls with the Fatty Liver and Kidney Syndrome (FLKS). The tissue was fixed at 10–25 min intervals after intravenous injection of 3H-oleic acid. The distribution of autoradiographic grains was analysed by the “circle method”. In normal cells most of the silver grains were associated with the cytoplasmic organelles. Lipid droplets and Golgi elements had the highest specific activity relative to the nuclear activity, which was little above background level. Lysosome-like bodies and mitochondria had lower values. In the cells of the FLKS-affected birds a large proportion of the grains was located over the lipid droplets, which are abundant in this condition. The specific activity of the cytoplasmic organelles was barely 2-fold higher than the nuclear activity. The results suggest that there is a diminished incorporation of esterified fatty acids by the organelles of these cells and that the excess is transferred to the lipid droplets. The identity of low electron density particles observed in the PCT cells of severely affected birds is discussed.
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    Scanning and transmission electron microscopic observations of the cloacal epithelia of the domestic fowl (1980)
    Springer
    Cell & tissue research 211 (1980), S. 83-93 
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    ISSN: 1432-0878
    Keywords: Epithelium ; Cloaca ; Electron microscopy ; Hen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithela of the three divisions (coprodaeum, urodaeum, proctodaeum) of the cloaca of the hen, and of the excretory ducts (colon, ureter, vagina) which join the divisions, are described using light microscopy, and scanning and transmission electron microscopy. Each region of the cloaca has its typical epithelium. Special attention is focussed in this study on the boundaries between the different epithelia. The coprodaeal epithelium does not differ considerably from that of the colon; a transitional zone is not visible. Distinct border zones, however, are observed between the other regions (ureter — urodaeum; vagina — urodaeum and proctodaeum; urodaeum-proctodaeum; proctodaeum — cutis). Although the vaginal opening is generally thought to lie in the urodaeum, our investigations show that at the vaginal opening into the cloaca the ciliated epithelium changes, on one border to a secretory epithelium characteristic of the urodaeum and on the other border to that characteristic of the proctodaeum. These observations are discussed in relation to functional aspects.
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    Gut hormones in Salamandra salamandra (1980)
    Springer
    Cell & tissue research 211 (1980), S. 331-343 
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    ISSN: 1432-0878
    Keywords: Gut hormones ; Endocrine cells ; Electron microscopy ; Immunocytochemistry ; Peptidergic innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histological, cytochemical and immunocytochemical methods were used in light and electron microscopical studies to demonstrate the presence of a neuroendocrine system in the gut of the urodele, Salamandra salamandra. Cytochemical stains capable of detecting peptide-producing endocrine cells demonstrate cells reacting with Masson's silver (argentaffin) method, Grimelius' argyrophil silver method, masked metachromasia method and the lead haematoxylin stain. Using antisera raised to a variety of mammalian gut peptides, cells containing bombesin-, gastrin-, somatostatin-, substance P- and glucagon-like immunoreactivity were identified; vasoactive intestinal polypeptide- and substance P-like immunoreactivities were found in nerve fibres in the submucous and myenteric plexus. No immunoreactivity was detected for motilin, gastric inhibitory polypeptide, cholecystokinin or secretin. The ultrastructure of the immunoreactive cells and nerves was revealed by the semithin/thin method. All the cells identified contained numerous electrondense secretory granules, which varied in their chracteristic morphological structure from one cell type to another. The evidence collected in this study indicates that a complex neuroendocrine system regulating gut function is present in this amphibian and may have developed prior to the emergence of the phylum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236453
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    Studies on the juxtaglomerular apparatus VI. Sympathetic innervation, catecholamines and the renin-angiotensin-system in rats and tree-shrews (Tupaia belangeri) (1980)
    Springer
    Cell & tissue research 212 (1980), S. 375-382 
    Details
    ISSN: 1432-0878
    Keywords: Juxtaglomerular apparatus ; Sympathetic innervation ; Renin-angiotensin system ; Electron microscopy ; Fluorescence microscopy ; Tupaia belangeri ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary It has previously been reported that the primitive primate Tupaia belangeri develops a renal failure when exposed to psychosocial stress. In order to learn if this high susceptibility to stress of the Tupaia kidney can be correlated with morphological and functional parameters of the Juxtaglomerular apparatus (JGA) and the renin-angiotensin system, comparative experiments were performed on Tupaia and rat. Our results reveal an outstandingly high potency of the JGA and the renin-angiotensin system in Tupaia as evident from the following findings: The Tupaia JGA contains a great number of epithelioid cells abounding in renin granules (electron microscopy). The renin content of the Tupaia kidney is considerably higher than in the rat (radio-immunoassay). The sympathetic innervation of the kidney and especially of the JGA is abundant in Tupaia (fluorescence and electron microscopy). Catecholamine contents of the kidney and other organs are significantly higher in Tupaia than in rats (spectrophotofluorometry). Our results support the previously developed concept of a potent intrarenal neuroendocrine interaction at the JGA level favouring, under certain conditions of social stress, the development of acute renal failure in Tupaia belangeri.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236504
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    Survival of satellite cells following exposure to the local anesthetic bupivacaine (Marcaine) (1980)
    Springer
    Cell & tissue research 209 (1980), S. 131-135 
    Details
    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Bupivacaine ; Degeneration ; Satellite cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat lumbrical muscles were incubated in a concentration of 10-2 M bupivacaine for 5 or 15 min and examined after further incubation in the absence of the drug for periods totalling 1, 2, and 3h. Electron microscopy showed that muscle fibers and their component organelles and myonuclei underwent a series of irreversible degenerative changes. However, satellite cells retained their normal morphology under similar conditions. It is concluded that satellite cells are responsible for the rapid regeneration of muscles that follows degeneration induced by bupivacaine. The role of satellite cells in muscle regeneration is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219929
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    The number and arrangement of elements in the lamina cartridge of the dragonfly Sympetrum rubicundulum (1980)
    Springer
    Cell & tissue research 206 (1980), S. 395-401 
    Details
    ISSN: 1432-0878
    Keywords: Dragonfly visual system ; Lamina ganglionaris ; Monopolar cells ; Optic neuropile ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Five monopolar cells and two long visual fibres are a consistent component of the lamina cartridge of the ventral half of the eye of the dragonfly Sympetrum rubicundulum. They communicate with the chiasm via a cartridge axon bundle comprising a minimum of ten fibres. The arrangement of these elements is documented with respect to the ommatidial photoreceptor axon bundle innervating them. These relationships are described both within the lamina cortex and in the cross-section of the underlying cartridge.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237969
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    The pineal complex of the three-spined stickleback, Gasterosteus aculeatus L. (1980)
    Springer
    Cell & tissue research 209 (1980), S. 11-28 
    Details
    ISSN: 1432-0878
    Keywords: Epiphysis cerebri ; Parapineal organ ; Fluorescence histochemistry ; Electron microscopy ; Gasterosteus aculeatus L ; Teleostei
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pineal complex of the three-spined stickleback (Gasterosteus aculeatus L.) was investigated by light and electron microscopy, as well as fluorescence histochemistry for demonstration of catecholamines and indolamines. The pineal complex of the stickleback consists of a pineal organ and a small parapineal organ situated on the left side of the pineal stalk. The pineal organ, including the entire stalk, is comprised mainly of ependymal-type interstitial cells and photoreceptor cells with well-developed outer segments. Both unmyelinated and myelinated nerve fibres are present in the pineal organ. Nerve tracts from the stalk enter the habenular and posterior commissures. A small bundle of nerve fibres connects the parapineal organ and the left habenular body. The presence of indolamines (5-HTP, 5-HT) was demonstrated in cell bodies of both the pineal body and the pineal stalk, and catecholaminergic nerve fibres surround the pineal complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219919
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    Hypothalamo-hypophysial function following the lesion of tanycytes in the median eminence of the rat (1980)
    Springer
    Cell & tissue research 209 (1980), S. 225-238 
    Details
    ISSN: 1432-0878
    Keywords: Tanycytes ; Median eminence ; Electron microscopy ; Rat ; Serum LH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The transport of hormones from the cerebrospinal fluid to the adenohypophysis by the tanycytes of the median eminence was examined in male rats. Electron microscopy revealed that all ependymal cells including the tanycytes disappear or degenerate in rats subjected to electric cauterization of the ependymal layer lining the third ventricle. However, the granular axons in the palisade layer of the median eminence remain intact. In rats subjected to electric lesion, no significant change was found in either the serum-LH level or in the weight of the adenohypophysis, testes, adrenal and thyroid glands. It is concluded that the tanycytes do not participate in the hypothalamic regulation of hypophysial function.
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    URL: http://dx.doi.org/10.1007/BF00237628
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    Induction of intranuclear microtubules in chick embryo fibroblasts by frog virus 3 (1980)
    Springer
    Cell & tissue research 209 (1980), S. 271-277 
    Details
    ISSN: 1432-0878
    Keywords: Intranuclear microtubules ; Chick embryo fibroblasts ; Frog Virus 3 ; Electron microscopy ; Tubulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intranuclear microtubules appear in chick embryo fibroblasts upon infection with Frog Virus 3 (FV 3). Both the diameter and the annular shape of the microtubule profiles, established from electron microscopic observations using a goniometer, suggest that they are identical to naturally occurring cytoplasmic microtubules. Furthermore, the use of vinblastine allowed demonstration of the tubulin composition of the intranuclear microtubules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237631
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    The origin of the dendritic reticulum cell (1980)
    Springer
    Cell & tissue research 209 (1980), S. 279-294 
    Details
    ISSN: 1432-0878
    Keywords: Germinal center reaction ; Dendritic reticulum cell ; Rabbit spleen ; Enzyme histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To obtain more information concerning the origin of dendritic reticulum cells, the development of germinal centers in the spleens of rabbits was investigated by conventional light microscopy, enzyme histochemistry, and electron microscopy. Washed sheep erythrocytes were used as antigen. Splenic tissue was examined on the 13th, 18th, 21st, 27th and 48th day after antigen administration. Electron microscopic investigations revealed transitional forms between typical fibroblastic reticulum cells, which formed the framework of the entire splenic white pulp, and typical dendritic reticulum cells. During this transformation, the enzyme histochemical pattern of alkaline phosphatase disappeared and a positive alpha-naphthyl acetate esterase reaction appeared in the transformed cells. On the basis of these findings, it is highly likely that dendritic reticulum cells develop through transformation of fibroblastic reticulum cells during the development of germinal centers in rabbit spleens. The characteristic folding of the surface membrane of dendritic reticulum cells is probably caused by the conspicuous increase in size of the Golgi apparatus, the detachment of vesicles, and the uptake of such vesicles by the cell membrane observed electron microscopically during the cellular transformation. Receptors that are of significance in antigen trapping might reach the cell surface in this manner, i.e., with the Golgi vesicles.
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    URL: http://dx.doi.org/10.1007/BF00237632
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    Phagocytosis of spermatozoa by the ovum of the domestic fowl, Gallus gallus at the time of fertilization (1980)
    Springer
    Cell & tissue research 206 (1980), S. 55-63 
    Details
    ISSN: 1432-0878
    Keywords: Phagocytosis ; Spermatozoa ; Ovum ; Fertilization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Spermatozoa with intact acrosomes, as well as those coming into contact with the ovum at a smaller angle, and morphologically abnormal spermatozoa reach the plasma membrane of the ovum via an extensively dissolved zone of the inner layer of the vitelline membrane. This zone is assumed to be formed by overlapping of two or more tunnels formed by spermatozoa that had previously come into contact with the ovum. When a spermatozoon comes into contact with the plasma membrane of the ovum, many cytoplasmic processes extend outwards and cover it. Thereafter, the plasma membranes of the processes fuse, thereby phagocytizing the spermatozoon. It is assumed that the phagocytized spermatozoa cannot undergo transformation into male pronuclei and that they degenerate soon after phagocytosis.
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    URL: http://dx.doi.org/10.1007/BF00233607
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    Ultrastructural changes in the urophysis of Mollienesia sphenops following adaptation to seawater (1980)
    Springer
    Cell & tissue research 207 (1980), S. 135-142 
    Details
    ISSN: 1432-0878
    Keywords: Caudal neurosecretory system ; Poeciliidae ; Electron microscopy ; Salinity changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The urophysis or neurohemal contact site of the caudal neurosecretory system of Mollienesia sphenops, the black molly, was studied in animals adapted to an artificial seawater environment. This species of fish was chosen for these studies because of its known ability to osmoregulate and its adaptability to the laboratory aquarium. The urophysis of freshwater acclimated mollys contained an abundance of neurosecretory granules. However, in fish subjected to a seawater environment for one week the number of neurosecretory granules was significantly decreased. In addition, there was an increase in blood cell infiltration of the urophysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239335
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    Monoaminergic neurons of the mudpuppy retina (1980)
    Springer
    Cell & tissue research 210 (1980), S. 269-282 
    Details
    ISSN: 1432-0878
    Keywords: Monoaminergic neurons ; Retina ; Amacrine cells ; Neurotoxins ; Mudpuppy, Necturus maculosus ; Neurotransmitters ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The mudpuppy retina was investigated with the histofluorescence method of Falck and Hillarp in normal animals and in animals injected intraocularly with α-methylnoradrenaline, 5,6-dihydroxytryptamine, or a combination of the two drugs. Catecholaminergic amacrine cells were found to form a thin layer of terminals at the border between the inner nuclear and the inner plexiform layers. Catecholaminergic interplexiform cells were not found. Indoleamine-accumulating amacrine cells were also observed. They are fifteen to twenty times more numerous than the catecholaminergic cells, and their terminals occur diffusely throughout the inner plexiform layer. In a number of eyes the majority of the indoleamine-accumulating terminals were eliminated with intraocular injections of the neurotoxin, 5,7-dihydroxytryptamine, but the reproducibility of this effect was not consistent. Intravitreal injections of 5,6-dihydroxytryptamine were used to label both types of neurons for electron microscopy. They were found to make conventional type synapses on amacrine cells and, less frequently, on bipolar cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237615
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    Merkel cells and nerve endings in the labial epidermis of a lizard (1980)
    Springer
    Cell & tissue research 210 (1980), S. 353-357 
    Details
    ISSN: 1432-0878
    Keywords: Merkel cells (reptiles) ; Epidermis ; Lizard ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Examination of the labial epidermis of the lizard Lacerta sicula revealed cells displaying all features of Merkel cells. These cells are located in the stratum basale of epidermal pegs and are arranged in clusters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237623
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    Effect of testosterone on the female hamster harderian gland pigmentation and ultrastructure (1980)
    Springer
    Cell & tissue research 207 (1980), S. 511-517 
    Details
    ISSN: 1432-0878
    Keywords: Female hamster ; Harderian gland ; Testosterone ; Tubular clusters ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Distinct differences occur in the pigmentation and ultrastructural features of the Harderian glands in male and female hamsters. The results of a study on the effect of testosterone on the fine structure of the female Harderian glands are presented here. Glands from three groups of hamsters were examined at intervals up to 49 days: (1) testosterone injected, receiving 2mg testosterone propionate in 0.1 ml sesame oil per day; (2) sham-injected, receiving 0.1 ml sesame oil per day; (3) untreated controls. Testosterone injections caused a reduction in the number of dark-brown pigment granules in the acinar cells starting on the 6th day, whereas clusters of tubules, typical of adult male glands, appeared on the 4th day and increased in number thereafter. Lamellar structures, normally present in the female gland, decreased in testosterone treated specimens. These changes reversed after cessation of testosterone treatment. It is concluded that exogenous testosterone administered to female hamsters modifies the pigmentation and ultrastructure of their Harderian glands towards the male type and that this is a reversable phenomenon. There also appears to be an inverse relationship between the presence of tubular clusters in the acinar cells, and the degree of pigmentation.
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    URL: http://dx.doi.org/10.1007/BF00224624
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