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  • Immunocytochemistry  (27)
  • Zea  (22)
  • Springer  (49)
  • Springer Science + Business Media
  • 1980-1984  (49)
  • 1981  (49)
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  • Springer  (49)
  • Springer Science + Business Media
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  • 1980-1984  (49)
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  • 1
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    Springer
    Planta 151 (1981), S. 15-25 
    ISSN: 1432-2048
    Keywords: Auxin (uptake, transport) ; Benzoic acid ; N-1-Naphthylphthalamic acid ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The validity of a chemiosmotic hypothesis for uptake of weak acids as an explanation for the accumulation of auxin by cells has been explored further by comparing the uptake of indole-3-acetic acid (IAA) by 1-mm segments of corn (Zea mays L.) coleoptiles with that of benzoic acid and two neutral indoles, indoleethanol and indoleacetonitrile, which do not ionize. These substances, while structurally related to IAA lack both auxin activity and polar transport. Uptake of IAA and benzoic acid increase with decreasing external pH, whereas the uptake of the two neutral indoles is independent of external pH. Although metabolism of IAA, during 90 min or less, is minimal and without significant effect on its uptake, metabolism of benzoic acid appears responsible for the apparent saturation of benzoic acid uptake at high concentrations. An inhibitor of auxin transport, N-1-naphthylphathalamic acid (NPA), stimulates uptake of IAA but has no effect on uptake of either benzoic acid or the two neutral indoles. Thus, NPA does not affect the driving forces for accumulation of weak acids but probably specifically decreases the flux of the auxin anions relative to undissociated auxin. Since the electrochemical potential of auxin anions is usually higher in than outside cells, blocking the anion flux with NPA would enhance auxin uptake. Azide, which abolishes accumulation of both IAA and benzoic acid, may simply collapse the pH gradient across the plasma membrane. In the absence of NPA, increasing concentrations of auxins or the analogoue β-naphthaleneacetic acid (β-NAA) exert two opposing effects on the uptake of IAA-depression and stimulation. Stimulation results from saturating the anion flux. With uptake fully stimulated by NPA, however, increasing concentrations of auxins or analogues only depress uptake of [3H]IAA. These results are consistent with more than one path for auxin transport each with a different dependence on concentration. In depressing NPA-stimulated IAA uptake, the effectiveness of β-NAA≧IAA≫α-NAA≫ benzoic acid, a specificity similar to that of an auxin binding site in vitro that has been implicated by others in auxin transport. The results support the general hypothesis that cellular auxin uptake and polar transport through tissues are chemiosmotically coupled to the electrochemical potential of auxin and protons.
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  • 2
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    Planta 153 (1981), S. 436-442 
    ISSN: 1432-2048
    Keywords: Aminopterin-resistant variants ; Cell culture ; Folate analog ; Variant selection ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Aminopterin-resistant cell lines of maize were isolated by two different procedures of callus selection and by plating suspension cultures on drugcontaining medium after mutagen treatment. Efficiencies of different methods of variant selection were compared. Four aminopterin-resistant cell lines were shown to be 10–40 times more resistant than the parental cell line, and they were also resistant to another folate analog, methotrexate. The results suggest that alterations in at least three different cell properties could be responsible for resistance; 1) increased dihydrofolate reductase activity, 2) altered aminopterin sensitivity of dihydrofolate reductase, and 3) reduced drug uptake. One of the resistant cell lines showed more than one alteration, but its resistance proved to be unstable. The results suggest that stable changes which may or may not be of genetic origin and also unstable physiological changes or a combination of both could lead to aminopterin resistance in maize cell cultures.
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  • 3
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    Planta 153 (1981), S. 443-446 
    ISSN: 1432-2048
    Keywords: ATPase ; Mitochondria ; Mycotoxin ; Pisum ; Zea ; Zearalenone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract At 5 and 10 μg ml-1 concentration, zearalenone (F-2), a mycotoxin produced by a number of species of the genus Fusarium, causes an inhibition of the oxidative phosphorylation of isolated plant mitochondria, while at 20 and 40 μg ml-1 it causes uncoupling. However, when the mitochondria are pre-incubated for 20 min with F-2, the uncoupling appears to be the prevailing effect. F-2 is also able to inhibit the mitochondrial ATPase activity (Mg2+-dependent). Conversely, F-2 (40 μg ml-1) does not alter the ATP level of maize roots and only slightly affects the ATPase activity of pea stem and maize root microsomal fractions. In addition, F-2 (10–40 μg ml-1) inhibits ATP synthesis catalyzed by rat liver mitochondria. It is suggested that the phytotoxicity of F-2, also known for its ability to collapse the transmembrane electric potential of maize roots, may be mainly linked to its ability to increase the proton permeability of the cell, similar to the common uncouplers.
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  • 4
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    Planta 153 (1981), S. 471-475 
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Geotropism (root) ; Growth inhibitor ; Light and root-cap inhibitor ; Root cap (inhibitor) ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Growth inhibitors were assayed from extracts of intact (attached) and of excised (cultured) root caps of Zea mays L., cv. Merit, the roots of which show a positive geotropic response only after exposure to light. If caps are intact at the time of illumination, at least two inhibitory substances are produced, an acid inhibitor and a neutral inhibitor, whereas if caps are detached from roots, placed in culture and then illuminated only the neutral inhibitor is formed. Cycloheximide retards inhibitor production in both intact and cultured caps. When [14C]mevalonic acid is included in the culture medium and the caps are illuminated, 15–25% of the recoverable 14C cochromatographs with the neutral inhibitor, whereas in caps cultured in the dark, this radiolabelling pattern is not observed. Cyloheximide in the light reduces the incorporation of 14C into compounds cochromatographing at the Rf of the neutral inhibitor. It is suggested that the neutral inhibitor may be important in the light-induced bending of roots.
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  • 5
    ISSN: 1432-2048
    Keywords: Auxin (immunoassay) ; Avena ; Coleoptiles (physiological tip) ; Enzyme immunoassay ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A specific solid-phase enzyme immunoassay for the detection of as little as 3–4 pg of indole-3-acetic acid (IAA) is described. The assay involves minimal procedural efforts and requires only standard laboratory equipment. Up to 50 samples in triplicate, processed simultaneously, can be assayed and evaluated in 2.5 h. As little as 1 mg oat coleoptile tissue is sufficient for a quantitative IAA analysis and little or no extract purification is necessary. Using this assay, levels of IAA have been determined in coleoptiles of maize and oat. The distribution of IAA within single coleoptiles was quantitated and the production of IAA during the regeneration of the physiological tip in Avena coleoptiles was investigated. The changes in levels of IAA and other major phytohormones were quantitated during the growth of oat coleoptiles.
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  • 6
    ISSN: 1432-2048
    Keywords: Cell-wall autohydrolysis ; β-D-Glucan ; Glucanase ; Hemicellulose ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The proteins dissociated from isolated Zea seedling cell wall using high-ionic-strength salt solutions have been found to include a number of enzymes which appear to participate in autolytic reactions of the cell wall. These enzymes caused extensive degradation of enzymatically inactive cell wall, liberating as much as 100 μg/mg dry weight over a 48-h period. Lithium chloride (3M) was shown to be most effective in yielding protein and wall-degrading activities. Molecular-sieve chromatography of the cell-wall protein resolved endo-β-D-glucanase and exo-β-1,3-glucanase (EC 3.2.1.58) activities when Avena glucan and laminarin, respectively, were employed as substrates. The exoenzyme (molecular weight around 60,000) was strongly inhibited by inorganic mercury at a concentration which suppressed the release of monosaccharide from autolytically active cell wall. The endo-β-D-glucanase (MW around 26,000), which showed a marked preference for substrates of mixed-linkage, exhibited features indicating that it initiates the autolytic solubilization of wall glucan. Cell-wall β-D-glucan, recovered as a component of an alkali-soluble cell-wall fraction, served as a substrate for the purified glucanases. Their hydrolysis pattern, assessed using gel exclusion chromatography and product analysis, confirmed that they hydrolyze β-D-glucan. The products generated by the endoglucanase were similar in molecular-size distribution to those liberated from autolytically active-wall. Exoglucanase activity was required for extensive hydrolysis of β-D-glucan in vitro. During coleoptile development the autolytic activity of the cell wall increased dramatically. This increased activity, however, did not parallel the growth potential of the tissue, but more closely reflected an increase in cell-wall β-D-glucan, the primary substrate for autolytic reactions.
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  • 7
    ISSN: 1432-2048
    Keywords: Acid growth ; Auxin ; Growth ; Root ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The role of proton excretion in the growth of apical segments of maize roots has been examined. Growth is stimulated by acidic buffers and inhibited by neutral buffers. Organic buffers such as 2[N-morpholino] ethane sulphonic acid (MES) — 2-amino-2-(hydroxymethyl)propane-1,3 diol (Tris) are more effective than phosphate buffers in inhibiting growth. Fusicoccin(FC)-induced growth is also inhibited by neutral buffers. The antiauxins 4-chlorophenoxyisobutyric acid (PCIB) and 2-(naphthylmethylthio) propionic acid (NMSP) promote growth and H+-excretion over short time periods; this growth is also inhibited by neutral buffers. We conclude that growth of maize roots requires proton extrusion and that regulation of root growth by indol-3yl-acetic acid (IAA) may be mediated by control of this proton extrusion.
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  • 8
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    Planta 151 (1981), S. 68-74 
    ISSN: 1432-2048
    Keywords: Energy metabolism ; Germination (seeds) ; Protein synthesis ; Temperature and seed germination ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Poor emergence of maize seedlings, due to high soil temperatures, is a major limitation of crop potential in the lowland tropics. Ability to germinate at high temperature (〉c. 37° C) is related to the temperature sensitivity of the embryo, and there is considerable genotypic variation for this character. Respiration and mitochondrial phosphorylation proceed normally in seeds imbibing at 41° C, and ATP levels are adequate for germination. However, the specific activities of several important enzymes are lower, and the rate of protein synthesis is severely reduced compared with seeds imbibing at 28° C. The depression of the rate of protein synthesis in the embryos of several tropical hybrids imbibing at high temperature correlated with their known temperature sensitivity. It is concluded that protein synthesis is an especially temperature sensitive process in germinating maize embryos, and that this is the principal reason for the sensitivity of germinating maize seeds to high temperature.
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  • 9
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    Planta 151 (1981), S. 75-80 
    ISSN: 1432-2048
    Keywords: Embryos (protein synthesis) ; Germination (seeds) ; Protein synthesis and temperature ; Temperature and protein synthesis ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The poor germination of maize seeds at high temperatures (〉37°C) is related to the low rate of protein synthesis by the embryo. The apparatus of translation was not heat-labile when embryos were incubated for 2 h at 41°C, and cell free extracts from seeds imbibed for 16 h at this temperature were able to translate exogenous mRNA, indicating that ribosomes and other subcellular components were present and functional. Analysis of polysome profiles from embryos imbibing at high temperature indicated that the low rate of protein synthesis was due to the non-availability of active mRNA.
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  • 10
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    Planta 151 (1981), S. 141-145 
    ISSN: 1432-2048
    Keywords: Chromosome isolation ; Petroselinum ; Polyethylene-glycol ; Protoplast (uptake of chromosomes) ; Triticum ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract For mass isolation of plant metaphase chromosomes, cultured cells of wheat (Triticum monococcum) and parsley (Petroselinum hortense) were synchronized by hydroxyurea and colchicine treatment. This synchronization procedure resulted in high mitotic synchrony, especially in suspension cultures of parsley in which 80% of the cells were found to be at the metaphase stage. Mitotic protoplasts isolated from these synchronized cell cultures served as a source for isolation of chromosomes. The described isolation and purification method yielded relatively pure chromosome suspension. The uptake of the isolated plant chromosomes into recipient wheat, parsley, and maize protoplasts was induced by polyethylene-glycol treatment. Cytological studies provided evidences for uptake of plant chromosomes into plant protoplasts.
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  • 11
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    Planta 151 (1981), S. 146-150 
    ISSN: 1432-2048
    Keywords: Georeaction (root) ; Growth inhibitors ; Growth (root) ; Root (georeaction, growth) ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The growth rate of the two sides of 10-mm apical segments prepared from primary roots and of intact primary roots of maize has been analyzed in both vertical and horizontal positions, using a filming method allowing continuous growth recording. The data showed that the georeaction began by a decrease in the overall elongation rate of the roots. This inhibition is effective on the lower side of the bending zone, where the growth is practically stopped during the period of maximum rate of geocurvature. In contrast, the growth is slightly enhanced on the upper part of the elongating zone.
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  • 12
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    Planta 152 (1981), S. 319-324 
    ISSN: 1432-2048
    Keywords: Nitrate influx (efflux, metabolism) ; Pennisetum ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Maize (Zea mays L.) and pearl millet (Pennisetum americanum (L.) Leeke) seedlings were exposed to [15N]nitrate for 1-h periods at eight times during a 24-h period (16–8 h light-dark for maize; 14–10 h for millet). Influx of [15N]nitrate as well as its reduction and translocation were determined during each period. The efflux of previously absorbed [14N]nitrate to the uptake solution was also estimated. No marked diurnal changes in [14N]nitrate efflux or [15N]nitrate influx were evident in maize. In contrast, [14N]nitrate efflux from millet increased and eventually exceeded [15N]nitrate influx during the late dark and early light periods, resulting in net nitrate efflux from the roots. The dissimilarity of their diurnal patterns indicates that influx and efflux are independently regulated. In both species, [15N]nitrate reduction and 15N translocation to shoots were curtailed more by darkness than was [15N]nitrate influx. In the light, maize reduced 15% and millet 24% of the incoming [15N]nitrate. In darkness, reduction dropped to 11 and 17%, respectively. Since the accumulation of reduced-15N in shoots declined abruptly in darkness, whereas that in roots was little affected, it is suggested that in darkness [15N]nitrate reduction occurred primarily in roots. The decrease in nitrate uptake and reduction in darkness was not related to efflux, which remained constant in maize and did not respond immediately to darkness in pearl millet.
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  • 13
    ISSN: 1432-2048
    Keywords: Immunocytochemistry ; (PEP carboxylase) ; PEP carboxylase ; Sorghum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The localization of phosphoenol pyruvate carboxylase (EC 4.1.1.3.1.) in the leaf cells of Sorghum vulgare was investigated by using three techniques: the conventional aqueous and non aqueous methods gave conflicting results; the immunocytochemical techniques clearly showed that the enzyme is predominantly located in the cytoplasm of mesophyll cells.
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  • 14
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    Planta 151 (1981), S. 499-505 
    ISSN: 1432-2048
    Keywords: Auxin ; Calorimetry ; Coleoptile ; Energetics ; Growth regulator ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Indole-3-acetic acid (IAA) promotes an increase in steady-state heat production by corn (Zea mays L.) coleoptile tissue; this increase is associated with an elevation in aerobic respiration rates. A detailed time dependence of the exothermic response to IAA was obtained using flow calorimetry. The latent period and magnitude of response were evaluated as a function of IAA concentration and pH. The data indicate that more than one response may occur. The optimal change in heat production was produced by an IAA concentration of 3·10-5 M. It was initiated within 5 min after the start of the IAA treatment, and reached a magnitude in excess of 25% of the tissue's basal heat production. Concentrations of IAA greater than 1·10-4 M resulted in diminished response(s), but the effect was strongly pH dependent. Several possibilities for the increased heat production triggered by IAA are discussed.
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  • 15
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    Planta 151 (1981), S. 506-511 
    ISSN: 1432-2048
    Keywords: Cell fractionation ; Cucurbita ; Malic enzyme ; Plasma membrane ; Subcellular localization ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A definite membrane fraction from Cucurbita hypocotyls, maize coleoptiles, and other plant tissues contains a NADP-dependent malic enzyme activity, up to 10% of overall tissue activity, and probably other soluble proteins. This “malic enzyme particle” is identified as plasmalemma on the basis of sedimentation behavior, density distribution in sucrose gradients, in comparison with enzyme markers, and sluggish penetration by the sugar Metrizamide. Enzyme binding to the plasma membrane is stable and scarcely sensitive to salts and EDTA, although all activity is released to the supernatant in the presence of Triton-X-100 or under hypotonic conditions. The properties of bound enzyme are similar to those of free enzyme in cell extracts. It is proposed that osmotically sensitive plasma membrane vesicles, containing cytoplasm fragments, are formed during homogenization. Low malic enzyme activities are also associated with Cucurbita proplastids.
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  • 16
    ISSN: 1432-2048
    Keywords: Lycopersicon ; Phetorespiration ; Photosynthesis ; Triacontanol ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tomato (C3-plants) and maize (C4-plants) were grown in a nutrient solution to which triacontanol was added twice a week. After about 4 weeks the triacontanol treatment caused a significant increase in the dry weight of the tomato plants. Leaf area and dry weight measurements of tomato leaves at different stages of development showed that the largest increase in growth was obtained when triacontanol treatment was initiated before bud formation. In maize, no effect of the triacontanol treatment on dry wieght was observed. Photosynthesis was inhibited by 27% in young leaves from triacontanol-treated tomato plants and 39% in the controls, when the oxygen concentration was raised from 2% to 21%. In maize no change in photosynthesis could be observed, neither after altered oxygen concentration nor after triacontanol treatment. The difference in the response of C3- and C4-plants to triacontanol indicates that it regulates processes related to photosynthesis.
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  • 17
    ISSN: 1432-2048
    Keywords: Cytoplasmic pH ; Fusicoccin ; Hydrogen-ion extrusion ; pH-stat ; Root ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 31P-Nuclear-magnetic-resonance spectra of maize (Zea mays L.) root tips, that had been induced to extrude large amounts of H+ in response to fusicoccin (FC) in the presence of potassium salts, indicate that the cytoplasmic pH does not become higher than that of controls. In fact, the cytoplasmic pH may become slightly (approx. 0.1 pH unit) lower in cells extruding H+. Estimations of the buffer capacity of the cells show that without active intracellular pH regulation, H+ extrusion caused by FC would cause the intracellular pH to rise by at least 0.6 pH unit h-1. Our results indicate that intracellular pH is tightly regulated even during extreme rates of acid extrusion, and that a rise in cytoplasmic pH is not the signal linking H+ extrusion with enhanced organic-acid synthesis or other intracellular responses to H+ pumping.
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  • 18
    ISSN: 1432-2048
    Keywords: Acid growth ; Geotropism ; Helianthus ; Phototropism ; Proton secretion ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By placing seedlings of sunflower (Helianthus annuus L.) or maize (Zea mays L.) on agar plates containing a pH indicator dye it is possible to observe surface pH patterns along the growing seedling by observing color changes of the indicator dye. Using this method we find that in geotropically stimulated sunflower hypocotyls or maize coleoptiles there is enhanced proton efflux on the lower surface of the organ prior to the initiation of curvature. As curvature develops the pattern of differential acid efflux becomes more intense. A similar phenomenon is observed when these organs are exposed to unilateral illumination, i.e. enhanced acid efflux occurs on the dark side of the organ prior to the initiation of phototropic curvature and the pattern of differential acid efflux intensifies as phototropic curvature develops. These observations indicate that differential acid efflux occurs in response to tropistic stimuli and that the acid efflux pattern may mediate the development of tropistic curvatures.
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  • 19
    ISSN: 1432-2048
    Keywords: Auxin uptake ; Coleoptile ; Fluorescein ; Morphactin ; Naphthylphthalamic acid ; Triiodobenzoic acid ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using both 1-mm segments of corn (Zea mays L.) coleoptiles and a preparation of membranes isolated from the same source, we have compared the effectiveness of several inhibitors of geotropism and polar transport in stimulating uptake of auxin (indole-3-acetic acid, IAA) into the tissue and in competing with N-1-naphthylphthalamic acid (NPA) for a membrane-bound site. Low concentrations of 2,3,5-triiodobenzoic acid (TIBA), NPA, 2-chloro-9-hydroxyfluorene-9-carboxylic acid (morphactin), and fluorescein, eosin, and mercurochrome all stimulated net uptake of [3H]IAA by corn coleoptile tissues while higher concentrations reduced the uptake of both [3H]IAA and another lipophilic weak acid, [14C]benzoic acid. Since low concentrations of fluorescein and its derivatives competed for the same membrane-bound site in vitro as did morphactin and NPA, the basis for both the specific stimulation of auxin accumulation and the inhibition of polar auxin transport by all these compounds may be their ability to interfere with the carrier-mediated efflux of auxin anions from cells. At higher concentrations, the decrease in accumulation of weak acids was nonspecific and thus may be the result of acidification of the cytoplasm and a general decrease in the driving force for uptake of the weak acids. Triiodobenzoic acid was an exception. Low concentration of TIBA (0.1–1 μM) were much less effective than NPA in competing for the NPA receptor in vitro, but little different from NPA in ability to stimulate auxin uptake. One possibility is that TIBA, a substance which is polarly transported, may compete with auxin for the polar transport site while NPA, morphactin, and the fluorescein derivatives may render this site inactive.
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  • 20
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    Planta 152 (1981), S. 397-407 
    ISSN: 1432-2048
    Keywords: Cytokinesis ; High voltage electron microscopy ; Mitosis ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The structure and distribution of cytoplasmic membranes during mitosis and cytokinesis in maize root tip meristematic cells was investigated by low and high voltage electron microscopy. The electron opacity of the nuclear envelope and endoplasmic reticulum (ER) was enhanced by staining the tissue in a mixture of zinc iodide and osmium tetroxide. Thin sections show the nuclear envelope to disassemble at prophase and become indistinguishable from the surrounding ER and polar aggregations of ER. In thick sections under the high voltage electron microscope the spindle is seen to be surrounded by a mass of tubular (TER) and cisternal (CER) endoplasmic reticulum derived from both the nuclear envelope and ER, which persists through metaphase and anaphase. At anaphase strands of TER traverse the spindle between the arms of the chromosomes. The octagonal nuclear pore complexes disappear by metaphase, but irregular-shaped pores persist in the membranes during mitosis. It is suggested that these form a template for pore-complex reformation during telophase. Phragmoplast formation is preceded by an aggregation of TER across the spindle at anaphase. Evidence is presented to suggest that the formation of the desmotubule of a plasmodesma is by the squeezing of a strand of endoplasmic reticulum between the vesicles of the cell plate.
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  • 21
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    Planta 153 (1981), S. 447-452 
    ISSN: 1432-2048
    Keywords: Auxin binding ; Root (auxin) ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Auxin binding onto membrane fractions of primary roots of maize seedlings has been demonstrated using naphth-1yl-acetic acid (NAA) and indol-3yl-acetic acid (IAA) as ligands. This binding is compared with the already well characterized interaction between auxins and coleoptile membranes. The results indicate that while kinetic parameters are of the same order for root and coleoptile binding, a number of differences occur with respect to location in cells and relative affinity. The possible significance of the existence of such binding sites in root cells is discussed in relation to auxin action.
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  • 22
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    Planta 153 (1981), S. 453-458 
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Gravireaction ; Growth inhibitors ; Root ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using gas chromatography-mass spectrometry (GC/MS) techniques of analyses, it has been found that endogenous abscisic acid (ABA) becomes asymmetrically distributed in the elongation zone of horizontal Zea mays (cv. LG 11) roots which are showing a positive gravitropic response. There is a relative increase in the ABA content of the lower half and a concomitant decrease for the upper half in such roots. Asymmetric distribution of ABA is also detected in the elongation zone of half-decapped roots.
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  • 23
    ISSN: 1432-2048
    Keywords: Aerenchyma ; Ethylene ; Gas space ; Oxygen and gas-space formation ; Roots, adventitious ; Silver ions ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have studied the role of ethylene in accelerating the lytic formation of gas spaces (aerenchyma) in the cortex of adventitious roots of maize (Zea mays L.) growing in poorly aerated conditions. Such roots had previously been shown to contain increased concentrations of ethylene. Ten day-old maize plants bearing seminal roots and one whorl of emerging adventitious roots were grown in nutrient solution bubbled with air, ethylene in air (0.1 to 5.0 μl l−1), or allowed to become oxygen-deficient in nonaerated (but not completely anaerobic) solution. Additions of 0.1 μl l−1 ethylene or more promoted the formation of aerenchyma, with lysis of up to 47% of the cortical cells. The effects of non-aeration were similar to those of exogenous ethylene. When silver ions, an ethylene antagonist, were present at low, non-toxic concentrations (circa 0.6 μM), aerenchyma formation was prevented in ethylene treated roots and in those exposed to oxygen deficiency. Silver ions also blocked the inhibiting effect of exogenous ethylene on root extension. By contrast, the suppression of aerenchyma formation by silver ions under oxygendeficient conditions was associated with a retardation of root extension, indicating the importance of aerenchyma for root growth in poorly aerated media. Rates of production of ethylene by excised roots were stimulated by a previous non-aeration treatment. The effectiveness of Ag+ in inhibiting equally the action on cortical cells of exogenous ethylene and of non-aeration, supports the view that gas space (aerenchyma) formation in adventitious roots ‘adpted’ to oxygendeficient environments is mediated by increased concentrations of endogenous ethylene. The possibility that extra ethylene could arise from increased biosynthesis of a precursor in root tissues with a restricted oxygen supply is discussed.
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  • 24
    ISSN: 1432-0878
    Keywords: Teleost ; Pars intermedia ; Immunocytochemistry ; PAP-technique ; MSH ; ACTH ; Endorphin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pars intermedia of S. mossambicus contains two different endocrine-cell types. The predominant cell type is lead-haematoxyline-positive and assumed to synthesize MSH and related peptides. The second cell type is PAS positive and its function and product(s) are unknown. Staining of light-microscopic and ultrathin sections with antisera against α-MSH, ACTH 1–24 and human β-endorphin revealed that only the lead-haematoxyline-positive cells of the pars intermedia react with these antisera, and that the secretory granules of these cells contain compounds that were immunoreactive to all three antisera. These findings are in line with the hypothesis that α-MSH, ACTH and endorphins are derived from the same precursor molecule. No specific reaction with one of the antisera could be detected in the PAS positive cells.
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  • 25
    ISSN: 1432-0878
    Keywords: Digestive tract ; Fish ; Gastrin-immunoreactive cells ; Pancreatic polypeptide-immunoreactive cells ; Somatostatin-immunoreactive cells ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gastrin, pancreatic polypeptide and somatostatin immunoreactive cells in the gut of two fish with stomachs (perch and catfish) and a stomachless fish (carp) were studied by immunocytochemistry. In the gastric mucosa of perch and catfish, cells showing gastrin and somatostatin-like immunoreactivity are found, scattered among the surface mucous cells and mucous neck cells. No pancreatic polypeptide (P.P.) immunoreactive cells are detected in the gastric mucosa. Cells showing gastrin and P.P.-like immunoreactivity are observed in the intestinal mucosa of perch, catfish and carp. In this location no somatostatin immunoreactive cells are found.
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  • 26
    ISSN: 1432-0878
    Keywords: α- and β-Endorphins ; Met-enkephalin ; Brain ; Immunocytochemistry ; Rana temporaria (Amphibia, Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the brain of Rana temporaria, two distinct systems reactive with α- and β-endorphin antisera, respectively, and with a met-enkephalin antiserum, have been detected immunohistochemically. Neurons reacting with α- and β-endorphin antisera are located (1) in the preoptic nucleus, and (2) in the pars ventralis of the tuber cinereum. Immunoreactive nerve fibres of both groups of perikarya end in the infundibular floor near the capillaries and the preoptico-hypophysial tract. Control reactions have shown that the immunoreactivity is suppressed by the corresponding antigens, but also by β-LPH. In view of these results the immunoreactive systems examined correspond to an α/β-endorphin system or a lipotropinergic system. Neurons reacting with the met-enkephalin antiserum are located in the paraventricular organ. Intense immunofluorescence was observed in the infundibular floor. Controls show that the labelling by met-enkephalin antiserum is exclusively suppressed by met-enkephalin. In the pituitary gland, on the other hand, α- and β-endorphin antisera reveal: 1) the MSH/ACTH-like cells of the pars intermedia and 2) the ACTH-like cells of the pars distalis.
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  • 27
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Biologically active peptides ; Lymnaea stagnalis ; Neurohormone ; Neurotransmitter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Perikarya and nerve fibers were immunocytochemically identified in the central nervous system of the pond snail Lymnaea stagnalis by means of the unlabelled antibody enzyme method with antisera to 15 biologically active peptides of vertebrates: vasopressin, vasotocin, oxytocin, α-melanocyte stimulating hormone (α-MSH), met-enkephalin, somatostatin, glucagon, insulin, glucose-dependent insulinotropic peptide (GIP), vaso-active intestinal polypeptide (VIP), gastrin, secretin, pancreatic polypeptide (PP), Substance P, calcitonin. No immunostaining was obtained with antisera to β-endorphin, cholecystokinin (CCK), neurophysin I and II. Particular neurons could be identified with two antisera (anti-vasopressin/vasotocin, anti-α-MSH/metenkephalin, anti-substance P/PP, anti-PP/gastrin). Apparently this indicates that populations of cells identified with a given antiserum may consist of more than one cell type. Only a few of the new peptidergic cells appeared to be identical with classical neurosecretory cells. Thus the growth hormone producing Light Green Cells stained with anti-somatostatin and the axon terminals of the ovulation hormone producing Caudo-Dorsal Cells with anti-met-enkephalin. Whether this indicates structural identity of the growth hormone with somatostatin and of the ovulation hormone with met-enkephalin remains to be investigated. Just like the classical neurosecretory cells a number of the new peptidergic cells (anti-glucagon, -insulin, -met-enkephalin, -somatostatin, and -PP positive cells) send their axons to the peripheries of commissures, connectives or nerves. Thus these cells can be considered as probably neuroendocrine. The classical neurosecretory cells release their products into the haemolymph from these sites. Other new peptidergic cells (e.g., anti-vasopressin, -vasotocin, -oxytocin and -GIP positive cells) have axons that terminate, probably synaptically, on other neurons, indicating that they are “more conventional” neurons, their products being neurotransmitters/neuromodulators. It can also not be excluded that some cells of a population containing a given peptide are neuroendocrine and others make contact with other neurons.
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  • 28
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Vasoactive intestinal polypeptide ; Radioimmunoassay ; Gut hormones ; Anura
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunocytochemical and radioimmunological techniques with region specific antisera have been used to identify a vasoactive intestinal polypeptide-like material in the anuran intestine. Seven species of Anura were investigated: Bombina bombina, Alytes obstetricans, Rana temporaria, Rana esculenta, Hyla arborea, Hyla crepitans and Bufo bufo. In five of the species (A. obstetricans, R. temporaria, H. arborea, H. crepitans and B. bufo) vasoactive intestinal polypeptide-like immunoreactive mucosal endocrine cells and nerve fibres in all layers of the gut wall, were detected by both immunofluorescence and peroxidase-antiperoxidase methods. In the other two species, R. esculenta and B. bombina, no mucosal endocrine cells were detected although the vasoactive intestinal polypeptide-immunoreactive nerve fibres were plentiful. Radioimmunoassay showed the presence of significant amounts of vasoactive intestinal polypeptide-immunoreactivity in intestinal extracts from all species. The highest quantities were present in those anurans with both immunostained cells and nerves. Gel permeation chromatography showed that most of the vasoactive intestinal polypeptide-like peptide eluted in a position identical to that of natural mammalian (porcine) vasoactive intestinal polypeptide. The results indicate that a vasoactive intestinal polypeptide-like peptide is well represented in the Anura and that it is immunologically very similar to the mammalian peptide.
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  • 29
    ISSN: 1432-0878
    Keywords: Anterior pituitary ; Corticotrophs ; Immunocytochemistry ; Growth hormone ; Prolactin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two antisera, Y-10 and Y-18 were raised in rabbits against synthetic human β-endorphin conjugated to bovine serum albumin and keyhole limpet haemocyanin respectively. Antiserum Y-10 has been shown by radioimmunoassay to be highly specific for human β-endorphin with minimal or no cross-reactivity against other pituitary peptides whilst antiserum Y-18 crossreacted on an equimolar basis against β-endorphin and β-lipotropin. When used in the immunohistochemical procedure, both antisera specifically stained the corticotrophs in human anterior pituitary tissue. A similar effect was observed when antiserum Y-18 was applied to rat anterior pituitary tissue in the immunohistochemical procedure. Y-10 antiserum, on the other hand, stained not only rat corticotrophs but also somatotrophs. The somatotrophin staining could not be attributed to the enkephalins reported to be present in these cells. The non-specific β-endorphin antiserum Y-18 was used to stain anterior pituitaries from dehydrated and adrenalectomized rats as well as rats of the Brattleboro strain. In tissues from the three experimental animals, cells that stained positively for β-endorphin did not give a positive immunoreaction for ACTH and vice versa in some other sections. It is concluded that under the physiological conditions, formalin fixation of the tissue causes the proopiocortin molecule to be “trapped” in a conformation such that either ACTH or β-endorphin-like determinants are available for reacting with the appropriate antiserum.
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  • 30
    ISSN: 1432-0878
    Keywords: Neuropeptides ; Substance P ; Chicken gut ; Radioimmunoassay ; Immunocytochemistry ; Smooth muscle motility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution and cellular localization of substance P in the chicken gut was studied by immunocytochemistry and immunochemistry. Substance P-containing nerve fibers are numerous in the gut wall. They occur in the smooth muscle layer as well as in the mucosa, where they are associated with blood vessels or surround the intestinal crypts. The fibers are particularly numerous in the myenteric and submucosal plexuses, where substance P-containing nerve-cell perikarya are also encountered. Substance P was found also in scattered endocrine cells of the small intestine, caeca and colon. Previously, bombesin-containing cells, which are numerous in the proventriculus, have been mistakenly identified as substance P cells due to crossreactivity of certain antisera against substance P. Immunochemistry revealed the highest concentration of substance P in the duodenum. The gel chromatographic behavior of chicken substance P differs slightly from that of synthetic bovine substance P, suggesting that chicken substance P differs structurally from mammalian substance P. Substance P-containing nerve fibers in the chicken gut develop slowly after hatching, apparently beginning in the duodenum; at approximately 20 weeks after hatching the distribution pattern is fully developed. A functional investigation was performed on the isolated chicken caecum to clarify the role of substance P in the contractile behavior of smooth muscle. Substance P contracted the caecum over a wide dose range; the contractile response was greater in 20 week-old chickens than in 4 and 10 week-old animals. Electrical field stimulation caused a relaxation of the caecum and a contraction upon cessation of stimulation. Neither of these responses, both of which are neurally mediated, were inhibited by adrenergic and cholinergic blockade. It is conceivable that the contractile response following electrical stimulation is caused by substance P released from nerve fibers in the smooth muscle.
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  • 31
    ISSN: 1432-0878
    Keywords: Pituitary ; Immunocytochemistry ; Prolactin ; Somatotropin ; Lepidosiren
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cellular binding sites of anti-oPRL IgG and anti-bSTH IgG were demonstrated in the pituitary glands of Lepidosiren paradoxa, Rana temporaria and Ambystoma mexicanum by means of the unlabeled antibody enzyme method by light and electron microscopy (the latter only in Lepidosiren). With the light microscope PRL or PRL-like substances and STH or STH-like substances were revealed in two different cell types in the distal lobe corresponding to the acidophils. However, as a result of the insufficient differentiation of the acidophils in Lepidosiren after staining with Brookes' procedure it was not possible to distinguish the two types of acidophils in this animal. Treatment with low dilutions of both anti-oPRL and anti-bSTH IgG revealed simultaneous immunocytochemical staining in both types of acidophils in Lepidosiren and in Rana. These results, indicating that there is antigenic cross-reaction between anti-oPRL and anti-bSTH IgG and both PRL and STH in these animals, are discussed. The electron microscopic investigations of Lepidosiren revealed that the specific anti-oPRL IgG reactive cells contain granules ranging in size from 200 to 300 nm, while the specific anti-bSTH IgG reactive cells contain smaller immunoreactive granules ranging from 80 to 160nm.
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  • 32
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    Protoplasma 105 (1981), S. 333-339 
    ISSN: 1615-6102
    Keywords: Immunocytochemistry ; Pea seed ; Protein histochemistry ; Storage proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The pea seed storage proteins legumin and vicilin have been localized by electron microscopy using a post-embedding immunocytochemical double-labelling technique. Highly purified antibodies from sheep, specific to legumin and vicilin, were sequentially reacted on sections of pea cotyledon tissue embedded in glycol methacrylate or Spurr's epoxy resin. The sheep antibodies were visualized indirectly by reaction with Staphylococcal Protein A labelled with colloidal gold. Two discrete sizes of colloidal gold particles can be used for simultaneous localization of two antigens. In near mature tissue, the storage proteins are restricted to organelles, called protein bodies. Individual protein bodies contain both legumin and vicilin.
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  • 33
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    Cell & tissue research 220 (1981), S. 115-123 
    ISSN: 1432-0878
    Keywords: Pars distalis ; California leaf-nosed bat ; Macrotus californicus ; LH ; FSH ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) cells were immunostained in the anterior pituitary lobe of the California leaf-nosed bat with antisera against the specific beta (β) subunits of rat LH and rat FSH employing the unlabeled immunoperoxidase technique. Selective immunochemical staining by both antisera was localized primarily in the same cell type. However, some cells consistently reacted solely with antisera to either LH-β or FSH-β. Whereas the immunoreactive LH-β cells, in general, stained more intensely than FSH-β cells they were usually less numerous. These cells were alcian-blue and PAS-positive, staining pink to purple. The LH/FSH cells were pleomorphic with eccentric nuclei, often with cytoplasmic extensions. They were found throughout the pars distalis.
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  • 34
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    Cell & tissue research 220 (1981), S. 279-292 
    ISSN: 1432-0878
    Keywords: Endocrine cells ; Gastrointestinal tract ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of gastrin-, cholecystokinin-, glucagon-, secretin-, vasoactive intestinal polypeptide-, substance P-, bombesin-, neurotensin-, motilin-, somatostatin- and avian pancreatic polypeptide-like cells, demonstrated by indirect immunocytochemistry, was studied in samples from the following regions: proventriculus, gizzard, pylorus, duodenum, upper and lower ileum, caeca and rectum. The pylorus is particularly rich in gastrin-, neurotensin- and somatostatin-like cells. No cells immunoreactive for gastric inhibitory polypeptide or insulin were detected. In a number of instances the same cells were found to stain with antisera raised to different gut peptides. This happened with antisera detecting gastrin- and neurotensin-like cells, with antisera to avian pancreatic polypeptide and glucagon and with antisera to secretin, vasoactive intestinal polypeptide, glucagon and substance P. The possibility that antigenic determinants to more than one peptide are contained in certain endocrine-like cells is considered.
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  • 35
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    Cell & tissue research 215 (1981), S. 41-45 
    ISSN: 1432-0878
    Keywords: Hypothalamic lesions ; Somatostatin fibers ; Median eminence ; Neural lobe ; Immunocytochemistry ; Frog
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A light microscopic immunocytochemical study of the brain of frogs with hypothalamic lesions was performed in order to obtain evidence concerning the origin of somatostatin fibers in the median eminence and neural lobe of the hypophysis. The results indicate that the somatostatin fibers of the neural lobe originate from somatostatin perikarya located in the prechiasmatic part of the hypothalamus and possibly also in the telencephalon. The somatostatin neurons of the pars ventralis tuberis cinerei do not send axons to the neural lobe. The frog median eminence contains axon terminals of somatostatin neurons located in the pars ventralis of the tuber cinereum. Many other somatostatin fibers of the frog median eminence originate from somatostatin neurons located outside the tuber cinereum. Most of these neurons probably lie in the preoptic hypothalamic region.
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  • 36
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    Cell & tissue research 215 (1981), S. 75-86 
    ISSN: 1432-0878
    Keywords: Pituitary cells ; Estrogen ; Progesterone ; Autoradiography ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of progesterone pretreatment on in vivo 3H-estrogen uptake by five anterior pituitary cell types was analyzed by means of a quantitative autoradiographic-immunocytochemical technique. Male and female rats castrated for 14 days show nuclear concentration of label in all five cell types one h after injection of 3H-estradiol, whether progesterone treated or not. The order of labeling intensity is gonadotropes ≧ lactotropes = somatotropes 〉 thyrotropes = corticotropes. Progesterone treatment induces a dramatic sexual dimorphism in estrogen uptake; it significantly increases 3H-estrogen uptake in all female cell types. In males, progesterone decreases uptake in gonadotropes while not altering uptake in other cell types.
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  • 37
    ISSN: 1432-0878
    Keywords: ACTH-opiocortin system ; Immunocytochemistry ; Median eminence ; Neural lobe
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By immunocytochemical methods, the present study describes ACTH-immunoreactive fibers in the pituitary stalk and neural lobe. This opiocortin-hypothalamo-neural lobe projection arises in a bed nucleus of perikarya in the basal hypothalamus, follows supraoptico-hypophyseal fibers in the zona interna of the median eminence, and distributes throughout the neural lobe. No ACTH-immunoreactive fibers project to the zona externa; some are present in the subependymal layer and at the lateral margins of the median eminence. Further studies must identify the role of these fibers in posterior lobe function. It remains also to be determined whether this system terminates upon primary pituitary portal capillaries and delivers opiocortin neuropeptides to the adenohypophysis.
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  • 38
    ISSN: 1432-0878
    Keywords: 17–39 ACTH ; LHRH terminals ; Median eminence ; Guinea pig ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary At the ultrastructural level a peptide immunocytochemically related to ACTH was localized in LHRH-containing terminals and nerve fibers of the palisade zone in the median eminence of the guinea pig. Precise comparisons of adjacent ultrathin sections stained for 17–39 ACTH and for LHRH made it possible to state clearly that in the two cases the staining was confined to granules containing both peptides. The significance of such an association remains open to discussion.
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  • 39
    ISSN: 1432-0878
    Keywords: Neurotensin ; Hypothalamus ; Coturnix quail ; Immunocytochemistry ; Neuropeptide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The hypothalamus of Japanese quail, Coturnix coturnix japonica, has been studied by means of the peroxidase-antiperoxidase immunocytochemical method, with the use of antibodies to synthetic neurotensin (NT). A number of immunoreactive neuronal perikarya occur in the medial preoptic nucleus of the rostral hypothalamus and a few in the accessory part of paraventricular nucleus and dorsal portion of the infundibular nucleus. Some of them correspond to the parvocellular neurons previously identified tentatively as neurosecretory (Mikami et al. 1975, 1976). Large numbers of immunoreactive neuronal fibers are found in the preoptic area, which extend as a remarkable fiber tract from this area to the ventral septal area and to the subfornical organ. A few immunoreactive fibers also extend ventrocaudally to the infundibular nucleus and to the neural lobe.
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  • 40
    ISSN: 1432-0878
    Keywords: Hypothalamic deafferentation ; Immunocytochemistry ; Vasopressin ; ACTH/opiocortin ; LHRH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Luteinizing hormone-releasing hormone (LHRH), vasopressin, and corticotropin systems were examined by immunocytochemical methods in male rats 2 to 20 days after deafferentation of the basal hypothalamus. Axonal degeneration of the vasopressin system (whose perikarya lie rostral to the island) and the corticotropin system (whose perikarya lie within the island) was examined and compared with the response of the LHRH system. Vasopressin immunoreactive staining was absent in the internal zone of the median eminence 10 and 20 days after deafferentation. Disruption of the efferent projections of the opiocortin system caused the loss of almost all fiber staining outside the island by the 5th postoperative day. LHRH staining in the median eminence was modestly reduced in 5 days, considerably reduced in 10 days and negligible 20 days after deafferentation. At 10 and/or 20 days after deafferentation densely stained fibers of all three systems were observed on both sides of the cut. Invasive vasopressinergic fibers reached the lateral median eminence by the 20th postoperative day. This study reports on the response of three neuropeptide systems after complete deafferentation and demonstrates that regeneration can occur across the knife cut.
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  • 41
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    Cell & tissue research 215 (1981), S. 499-504 
    ISSN: 1432-0878
    Keywords: Androgen receptors ; Pituitary gland ; Rhesus monkey ; Autoradiography ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The uptake and retention of radiolabelled dihydrotestosterone by the pituitary gland was examined in the rhesus monkey. Two animals were given an intravenous injection of 1.0μg/kg 3H-dihydrotestosterone (DHT) alone while one monkey received both the labelled androgen and 100μg/kg of unlabelled steroid. One and a half hours later, they were sacrificed. The pituitary glands were removed and processed for autoradiography and immunocytochemistry. Autoradiographic localization of DHT was discernible in the partes nervosa, intermedia and distalis, albeit the highest concentration of radiolabelled cells was noted in the pars distalis. Immunocytochemical staining with antibodies to rat PRL, human TSHβ and ovine LHβ revealed a population of steroid-concentrating cells that contained TSH and a second group that contained LH. None of the cells that reacted with the anti-PRL serum were radiolabelled.
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  • 42
    ISSN: 1432-0878
    Keywords: Proctolin ; Periplaneta americana ; Terminal ganglion-hindgut system ; Immunocytochemistry ; Cobalt iontophoresis technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the American cockroach, the distribution and connections of neuronal elements of the terminal ganglion-proctodeal nerve-hindgut system were investigated by means of immunohistochemical methods and axonal CoCl2 iontophoresis. Proctolinlike immunoreactivity was localized within neurons of the terminal ganglion projecting into the proctodeal nerve on the one hand, and in nerve cells without a direct connection to this system on the other. Immunohistochemically, in whole mount preparations fibres of the proctodeal nerve and terminal structures in the hindgut musculature exhibit strong proctolinlike immunoreactivity. At the light- and electron-microscopic levels the pathways of about 30 somata of the proctodeal neural system were characterized by cobalt chloride iontophoresis. The relationships of cobalt filled and immunoreactive neuronal structures are discussed. For the preparation of tritiated proctolin we thank Dr. S. Reißmann, WB Biochemie, Sektion Biologie, FSU Jena
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  • 43
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Neurophysins ; Intra-axonal transport ; Immunocytochemistry ; Colchicine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Small doses (3.5 μg and 7 μg) of colchicine injected intracisternally caused an interruption of transport of secretory material from the supraoptic and paraventricular nuclei of the hypothalamus to the neural lobe of the pituitary gland. Transport was assessed by direct measurement of the incorporation of [35S] cysteine into neurophysins, by radioimmunoassay of accumulated material in discrete areas of the system and by immunocytochemistry. The larger dose (7 μg) switched off transport completely during the first 24 h but the system began to recover within three to four days. Colchicine had little, if any, effect on synthesis; comparison of the relationships of the apparent amounts of immunoreactive neurophysins and immunoreactive hormones in the arrested product led to the conclusion that processing of the hormone precursors continues within the secretory granules which accumulated in the perikarya.
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  • 44
    ISSN: 1432-0878
    Keywords: Magnocellular neurosecretory system ; Cholecystokinin ; Oxytocin-neurophysin neurons ; Immunocytochemistry ; Neuropeptides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The existence of cholecystokinin in the posterior hypophysis and its hypothalamic origin have been unequivocally demonstrated. Immunocytochemical evidence is presented for the coexistence of gastrin-cholecystokinin and oxytocin-neurophysin I immunoreactivities in some magnocellular neurons of the supraoptic and paraventricular nuclei both in rat and bovine hypothalamus.
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  • 45
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    Cell & tissue research 221 (1981), S. 257-267 
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Human pituitary hormone antisera ; Platyfish ; Pituitary gland
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In this communication we describe the immunocytochemical cross-reactivity between antisera to various human pituitary hormones and specific hormone producing cell types in the pituitary gland of sexually mature male platyfish (Xiphophorus maculatus). Antisera to human pituitary hormones cross-reacted either with cells known to produce corresponding hormones (or hormone subunits) in the platyfish (e.g., ACTH, prolactin, TSH β, LH α, FSH α, TSH α) or with no pituitary cells at all (e.g., LH β, FSH β). The one exception was antiserum to human growth hormone which cross-reacted with MSH and ACTH producing cells. The platyfish pituitary is proposed as a test system for immunocytochemically screening antisera for purity and specificity in order to determine their applicability in particular studies.
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  • 46
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    Cell & tissue research 218 (1981), S. 659-662 
    ISSN: 1432-0878
    Keywords: Peptides ; Subcommissural organ ; Secretion ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The results of a preliminary immunocytochemical investigation on the subcommissural organ (SCO) in rats show that (1) Reissner's fiber (RF) or essential compounds of the RF are produced by the SCO, (2) the immunoreactive material is produced in the epithelial cells of the SCO as well as in the hypendymal cells, and (3) the immunoreactive material of the SCO belongs to a category of endogenous peptides to date not demonstrable immunocytochemically in other brain structures.
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  • 47
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    Cell & tissue research 219 (1981), S. 213-216 
    ISSN: 1432-0878
    Keywords: Relaxin ; Human pregnancy ; Corpus luteum ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Corpora lutea from 12 pregnant women were prepared for immunohistochemical localization of relaxin using a highly specific antiserum. A positive response is given by luteal cells that are diffusely distributed throughout the corpus luteum. These cells do not form a distinctive group in any particular area. A negative response is seen in the adjacent ovarian tissue, and also in nongestational corpora lutea in an early luteal phase.
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  • 48
    ISSN: 1432-0878
    Keywords: Opsonin ; Agglutinin ; Amoebocytes ; Immunocytochemistry ; Lymnaea stagnalis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Monolayers of blood cells (amoebocytes) and sections of connective tissue and of amoebocyte pellets of the freshwater pulmonate gastropod Lymnaea stagnalis were stained immunocytochemically with antisera to snail agglutinin/opsonin. The presence of this substance was demonstrated light microscopically both in the cytoplasm and on the cell membrane of amoebocytes. This suggests that amoebocytes synthesize agglutinin/opsonin, and bear it at their surface as receptors for foreign materials.
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  • 49
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    Cell & tissue research 220 (1981), S. 223-230 
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Freeze-dried brain ; Fluid-fixed brain ; LHRH ; Somatostatin ; Neurophysin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunocytochemical staining of luteinizing hormone-releasing hormone (LHRH), somatostatin, and neurophysin was compared in rat brains fixed with 1) formalin, 2) Bouin's solution, 3) freeze-dried (FD), or 4) freeze-dried + paraformaldehyde vapor perfused (FDV). The distribution of LHRH fibers was similar in all preparations; however, beads of granular reaction product often appeared finer and more numerous in the median eminence of FD- and FDV brains. Positively stained LHRH perikarya were not observed in any of the preparations. In contrast, somatostatin-immunoreactive perikarya were present in the fluid-fixed and FD brains, although few were observed in FDV brains. Somatostatin-immunoreactive fibers were present in all preparations, but appeared most numerous in the median eminence of FD brains. Staining of neurophysin-containing perikarya and fibers was similar in all preparations. These observations suggest that the FD brain can provide a suitable tissue substrate for immunocytochemistry, demonstrating staining comparable to or surpassing that of more conventional preparations. However, staining of antigens in FD brain was not uniformly successful and may depend on stereochemical characteristics of each antigen as well as properties of the primary antisera used in the staining procedure.
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