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Jacek Kęsy Beata Maciejewska Magdalena Sowa Magdalena Szumilak Krzysztof Kawałowski Maja Borzuchowska Jan Kopcewicz 《Plant Growth Regulation》2008,55(1):43-50
It has been shown that both IAA and ethylene application inhibit flower induction in the short-day plant Pharbitis nil. However application of IAA has elevated ethylene production in this plant, as well. Strong enhancement of ethylene production
is also correlated with the night-break effect, which completely inhibits flowering. In order to determine what the role of
IAA and ethylene is in the photoperiodic flower induction in Pharbitis nil, we measured changes in their levels during inductive and non-inductive photoperiods, and the effects of ethylene biosynthesis
and action inhibitors on inhibition of flowering by IAA. Our results have shown that the inhibitory effect of IAA on Pharbitis nil flowering is not physiological but is connected with its effect on ethylene biosynthesis. 相似文献
3.
The future study of colon disease in captive callitrichid colonies may require manipulation of diets. The limited knowledge of the nutritional requirements for these species and the varied diets and supplementations fed to these animals in various colonies suggest the importance of testing the palatability and acceptability of diets for these primates. Individually housed cotton-top tamarins (Saguinus oedipus) were given either the regular Oak Ridge Associated Universities (ORAU) diet (monkey chow slurry, canned diet and supplements), a similar slurry using an experimental natural ingredient diet plus supplements, or the experimental diet without supplements. Neither dry food consumption, body weight, fecal output, nor the histological evaluation of the colons were affected by these diets. Daily intake of protein and calories were higher than previously reported estimates for the species. These results demonstrate that a natural ingredient non-sweetened pelleted diet is palatable for cotton-top tamarins for a period of 3.5 months, however, further testing over longer time periods is necessary. The nonnutritional (e.g. psychological) advantages of providing a highly diverse diet to primates housed in a relatively monotonous environment should be considered before adopting such a diet for an entire colony. 相似文献
4.
L. H. Clapp A. M. Gurney N. B. Standen P. D. Langton 《The Journal of membrane biology》1994,140(3):205-213
Tension and patch clamp recording techniques were used to investigate the relaxation of rabbit pulmonary artery and the properties of the K+ current activated by levcromakalim in isolated myocytes. Under whole-cell voltage clamp, holding at –60 mV in symmetrical 139 mm K+, levcromakalim (10 m) induced a noisy inward current of –116 ± 19 pA (n = 13) which developed over 1 to 2 min. This current could be blocked by either glibenclamide (10 m) or phencyclidine (5–50 M) and was unaffected when extracellular Ca2+ was removed. Both these drugs inhibited the levcromakalim-induced relaxation of muscle strips precontracted with 20 mm [K+]
o
. Application of voltage ramps in symmetrical 139 mm K+ confirmed that the levcromakalim-induced current was carried by K+ ions and was weakly voltage dependent over the potential range from –100 to +40 mV.The unitary current amplitude and density of the channels underlying the levcromakalim-activated whole-cell K+ current was estimated from the noise in the current record. We estimate that levcromakalim caused activation of around 300 channels per cell, with a single channel current of 1.1 pA, corresponding to a slope conductance of about 19 pS. Furthermore, cells dialyzed with an ATP-free pipette solution developed a large noisy inward current at –60 mV, which could subsequently be blocked by flash photolysis of caged ATP. Analysis of the noise associated with this current indicated that the single channel amplitude underlying the ATP-blocked current was 1.4 pA, a value similar to that estimated for the levcromakalim-induced current. We conclude that the conductance of this ATP-sensitive channel is likely to be small under physiological conditions and that it is present at low density.We thank SmithKline & Beecham for the gift of levcromakalim, ICI Pharmaceuticals for the gift of charybdotoxin and Prof. D. Colquhoun for the noise analysis programs. We also thank Mr. R. Davey for technical assistance with tension experiments. This work was supported by the British Heart Foundation and the Wellcome Trust. L.H.C. is a Wellcome Research Fellow and P.L. is an intermediate fellow of the BHF. 相似文献
5.
Beata Bartodziejska Joanna Radziejewska-Lebrecht Maria Lipinska Yuriy A. Knirel Leonid O. Kononov Anatoly Y. Chernyak Hubert Mayer Antoni Rozalski 《FEMS immunology and medical microbiology》1996,13(2):113-121
Abstract In DOC-PAGE, lipopolysaccharide (LPS) of Proteus mirabilis R14/1959 (Rb-type) mutant showed a ladder-like migration pattern indicating the presence of a high molecular weight polysaccharide chain. The isolated polysaccharide, called T-antigen because of similarity with the T1 chain of Salmonella friedenau LPS, contained d -glucose, d -galacturonic acid ( d -GalA), and d -GlcNAc in molar ratios 2:1:1 and was structurally different from the O-antigen of the parental S-strain P. mirabilis S1959 but identical to the O-antigen of another S-strain Proteus penneri 42. The importance of a d -GalA( l -Lys)-containing epitope, most likely present in the core region of LPS, and of GalA present in the T-antigen chain in manifesting the serological specificity of P. mirabilis R14/1959 were revealed using rabbit polyclonal homologous and heterologous R- and O-specific antisera and the appropriate antigens, including synthetic antigens which represent partial structures of various Proteus LPS. 相似文献
6.
Two series of amino-modified silicate gels prepared by sol-gel processing were used to absorb Cu(II), Ni(II), Co(II), Mn(II) and Cr(III) from aqueous solutions. These easily prepared sorbents with various content of primary amino groups in series (A) or primary and secondary amino groups in series (AA) have reasonable stability. The gel composition, time and concentration dependence of the uptake of the metal ions by these materials were studied systematically. These materials would be further used as supports to disperse catalytically active phases by conventional wet chemical procedures. Apart from this they demonstrate potential for the preconcentration aid for transition metal analysis. 相似文献
7.
The distribution of radioactivity in tumor-susceptible (liver and lung) and non-tumor-susceptible (heart, forestomach, and esophagus) tissues of male RFM mice was investigated at timed intervals following a single intragastric administration of 14C-labeled DMN.3 The greatest amount of radioactivity was associated with the tumor-susceptible tissues—liver and lung. At 15 min, the relative amount of radioactivity in the homogenates of heart, forestomach, esophagus, livers and lung was 1, 2, 3, 10, and 70, respectively. The AS components of lung contained about six times as much radioactivity as the liver 15 min after administration; at 16 hr, the level of radioactivity had decreased and was equal in amount. The AI components of both tumor-susceptible tissues incorporated much less radioactivity than the AS components, indicating that only a small amount of methyl label is covalently bound to cellular macromolecules. The amount or radioactivity in the AI components ranged from 2–34% in the lung and from 11–33% in the liver. In the lung C-fraction the range of radioactivity was 75–89% for the AS components and 52–74% for the AI components. The radioactivity in the AS components of liver C-fraction ranged from 50–89%, and from 52–68% for the AI components. The results suggest differences in the affinity, transport, and/or metabolism of DMN between liver and lung, as well as between tumor-susceptible and non-tumor-susceptible tissues. 相似文献
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9.
Maja Pijet Barbara Pijet Anna Litwiniuk Beata Pajak Barbara Gajkowska Arkadiusz Orzechowski 《Cytokine》2013,61(2):445-454
Reduced lean body mass in genetically obese (ob/ob) or anorectic/cachectic subjects prompted us to verify the hypothesis whether leptin, white adipose tissue cytokine, might be a negative organizer of myogenesis. Recombinant leptin (100 ng/mL) stimulated mitogenesis together with the raise in T202/Y204P-ERK1/2 protein expression. Concomitantly, it impaired cell viability and muscle fiber formation from C2C12 mouse myoblasts. Detailed acute and chronic studies with the use of metabolic inhibitors revealed that both JAK/STAT3 and MEK/MAPK but not PI3-K/AKT/GSK-3β signaling pathways were activated by leptin, and that STAT3 (Y705P-STAT3) and MEK (T202/Y204P-ERK1/2) mediate these effects. In contrary, insulin evoked PI3-K-dependent phosphorylation of AKT (S473) and GSK-3β (S9) and insulin surpassed leptin-dependent inhibition of myogenic differentiation in PI3-K-dependent manner. GSK-3β seems to play dual role in muscle development. Insulin-dependent effect on GSK-3β (S9P-GSK-3β) led to accelerated myotube construction. In contrary, leptin through MEK-dependent manner caused GSK-3β phosphorylation (Y216P-GSK-3β) with resultant drop in myoblast fusion. Summing up, partially opposite effects of insulin and leptin on skeletal muscle growth emphasize the importance of interplay between these cytokines. They determine how muscle mass is gained or lost. 相似文献
10.
Otylia Kowal-Bielecka Marek Bielecki Serena Guiducci Beata Trzcinska-Butkiewicz Ma?gorzata Michalska-Jakubus Marco Matucci-Cerinic Marek Brzosko Dorota Krasowska Lech Chyczewski Krzysztof Kowal 《Arthritis research & therapy》2013,15(3):R69