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  • Articles  (9)
  • IAA  (3)
  • IBA  (3)
  • indole-3-acetic acid  (3)
  • Bone mineral metabolism  (2)
  • Citrus  (2)
  • Springer  (9)
  • National Academy of Sciences
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  • Articles  (9)
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  • Springer  (9)
  • National Academy of Sciences
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  • 1
    ISSN: 1432-0827
    Keywords: Rapamycin ; Bone mineral metabolism ; Bone Gla protein ; Immunosuppressants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Immunosuppressants have adverse effects on bone mineral metabolism in animal and human studies, with corticosteroids producing low-turnover osteopenia, and cyclosporin-A (CsA) producing high-turnover osteopenia. Rapamycin (RAPA) is a new immunosuppressant reported to be at least 10 times more potent than CsA, and acts via a different pathway to CsA and the other new immunosuppressant FK506. This study investigated the effects of RAPA on bone mineral metabolism in the rat. Forty-two, 10-week-old, male Sprague Dawley rats were divided into three groups, and treated according to the following protocol: group A (control) received RAPA vehicle by daily gavage for 14 days (n = 12); group B (high dose RAPA) received RAPA 2.5 mg/kg/day by daily gavage for 14 days (n = 15); group C (low dose RAPA) received RAPA 1.25 mg/kg/day by daily gavage for 14 days (n = 15). Rats were weighed and bled on days 0, 7, and 14 for measurement of blood ionized calcium, bone Gla protein (BGP), parathyroid hormone (PTH), and 1,25(OH)2D. Tibial bone histomorphometry was determined on day 14 after double-calcein labeling. Weight gain was similar in the two groups treated with RAPA compared with control animals. High-dose RAPA (group B) transiently depressed serum BGP levels on day 7, with elevated blood ionized calcium levels on day 7, and lowered 1,25(OH)2D levels on day 14. Serum PTH levels were unchanged. Low dose RAPA (group C) did not affect calciotropic hormones. Histomorphometric analyses of tibial metaphyses revealed that parameters of bone formation and resorption were not significantly different in the groups treated with RAPA (group B and C) compared with control animals (group A). Trabecular bone volume (BV/TV) in group B (high-dose RAPA) (15.39 ± 1.01%) and C (low-dose RAPA) (15.38 ±0.57%) was not significantly altered compared with group A (control) (16.42 ± 0.86%). Short-term treatment with RAPA, unlike CsA, does not result in excess resorption and loss of bone volume. The depressed serum 1,25(OH)2D levels seen with high-dose RAPA therapy may adversely effect bone mineral metabolism in the long term.
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  • 2
    ISSN: 1432-0827
    Keywords: Diabetes mellitus ; Amylin ; Osteoporosis ; Bone mineral metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Amylin is normally secreted in a regulated fashion by the pancreatic β-cells in parallel with insulin and has been reported to have bone-conserving properties. Type I diabetes mellitus results in a low-turnover osteopenia in the presence of decreased amylin, which is in contrast to type II diabetes where less bone loss, in the presence of high amylin levels, occurs. We investigated the effects of amylin on bone mineral metabolism in normal and dibetic (streptozotocin-induced) rats, in order to ascertain whether amylin would modify the streptozotocin-induced diabetic osteopenia. Tenweek-old male Sprague-Dawley rats were randomized as follows: group A (n=18) received normal saline; group B (n=18) received amylin; group C, diabetic rats (n=23), received normal saline; and group D, diabetic rats (n=23), received amylin. Amylin (100 pmol/100 g b. w.) was administered by a daily subcutaneus injection. Double calceinlabeled tibiae were removed for histomorphometric analysis followed sacrifice on day 19. Results showed no difference in blood ionized calcium between groups. Blood glucose remained above 600 mg/dl in the diabetic animals and was not affected by the administration of amylin. Serum osteocalcin, insulin-like growth factor-1 (IGF-1), parathyroid hormone (PTH), and 1,25 dihydroxyvitamin D [1,25(OH)2D] were significantly lower in the diabetic rats compared with control group A by day 19. Amylin produced higher levels of serum osteocalcin in group B on day 9 (P〈0.05) compared with controls but returned to control values (group A) by day 19; no such change occurred in the diabetic group. Amylin administration did not influence IGF-1, 1,25(OH)2D or PTH levels compared with the untreated animals. Analysis of the bone histomorphometry showed a low-turnover osteopenia in the diabetic animals. Amylin administration resulted in a significant increase in bone volume in the normal rats, group B (P〈0.05), but was unable to significantly alter this parameter in the diabetic animals. In conclusion, amylin has a beneficial effect on the bone metabolism of the rat in vivo by increasing bone volume. It is, however, unable to overcome the osteopenia caused by streptozotocin-induced diabetes mellitus at the doses used in this study.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 72 (1986), S. 569-574 
    ISSN: 1432-2242
    Keywords: Phytophthora citrophthora ; Citrus ; Culture-filtrate ; Indole acetic acid ; Protoplast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nucellar calli from four Citrus cultivars with known resistance to the Phytophthora citrophthora pathogen were chosen as experimental material to test the pathogen's response to culture filtrate (CF). Sensitivity of the four calli to CF of the fungus was in reverse order to what is known on the susceptibility of the cultivars in vivo. Sensitivity of protoplasts derived from the same four calli to 2,4-dichlorophenoxyacetic acid (2,4-D) was in the same order as that of calli to CF. Protoplasts derived from calli selected for tolerance to CF showed a higher plating efficiency with increasing concentration of CF in the medium. TLC and GLC determinations showed the presence of indole acetic acid in the culture filtrate. Results indicate that CF of P. citrophthora cannot be used as a selection tool in vitro.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plant growth regulation 8 (1989), S. 215-223 
    ISSN: 1573-5087
    Keywords: IAA ; IBA ; conjugated IBA ; rooting ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Indole-3-butyric acid (IBA) was identified by thin layer chromatography, gas-liquid chromatography and gas chromatography-mass spectrometry in kernels and leaves of corn (Zea mays) var. Hazera 224. Free and ester conjugated IBA were present in dry and germinating corn kernels and leaves. This is the first report of IBA in a monocotyledonous plant and, as far as we know, the first evidence for the presence of conjugated IBA.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Plant growth regulation 12 (1993), S. 17-22 
    ISSN: 1573-5087
    Keywords: indole-3-acetic acid ; indole-3-butyric acid ; IBA-aspartic acid ; IBA-glucose ; protea ; rooting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Indole-3-butyric acid (IBA) greatly enhanced the rooting of an early-flowering variety of protea, Leucadendron discolor, but had very little effect on a late-flowering variety. IBA transport and metabolism were studied in both varieties after incubating the cuttings in 3H-IBA. More of the radio-label was transported to the leaves of the easy-to-root variety than the difficult-to-root (35–45% and 10%, respectively). IBA was metabolized rapidly by the cuttings of both varieties and after 24 h most of the label was in the new metabolite. However, free IBA (about 10%) was present in the cuttings during the whole period up to the time of root emergence (4 weeks). More free IBA was accumulated in the base of easy-to-root cuttings, while in the difficult-to-root variety most of the IBA was found in the leaves. The metabolite was identified tentatively as an ester conjugate with a glucose. It is possible that IBA-glucose serves as a source for free IBA, and the difference between the varieties is a consequence of the free IBA which is released, transported and accumulated in the site of a root formation.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Plant growth regulation 14 (1994), S. 7-14 
    ISSN: 1573-5087
    Keywords: Arabidopsis thaliana ; IBA biosynthesis ; indole-3-acetic acid ; indole-3-butyric acid ; α-naphthylacetic acid ; phenylacetic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Indole-3-butyric acid (IBA) was identified by HPLC and GC-MS as one of the reaction products after incubation of sterile cultures of Arabidopsis thaliana seedlings with labeled indole-3-acetic acid (IAA). This is the first demonstration of IBA biosynthesis in a dicotyledonous plant. After 1 h of incubation most of the IBA was found in the free form, while after longer periods of incubation most of it was detected in conjugated forms. Formation of IBA conjugates was inhibited by the addition of unlabeled IBA. The biosynthesis of IBA and its conjugates was followed throughout the development of the seedlings and at different pH values. All parts of the plant (isolated roots, leaves, shoots and flowers) were able to convert IAA to IBA to the same extent. IAA was more readily transported than IBA in mature Arabidopsis plants. Feeding of labeled phenylacetic acid (PAA) and α-naphthylacetic acid (NAA) to Arabidopsis seedlings resulted in a new small peak which was hydrolyzed by 7N NaOH, but the formation of compounds with longer side chains (analogous to IBA) could not be detected.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Plant growth regulation 17 (1995), S. 127-132 
    ISSN: 1573-5087
    Keywords: anaerobic methanogenic thermophilic digestion ; auxin ; biogas ; IAA ; IBA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A large amount of solid waste remains after the production of instant coffee. This waste has to be moved to dumps, where it poses a threat of environmental pollution. Treatment of this waste by anaerobic methanogenic thermophilic digestion produced, besides biogas, a digested slurry which was used as a growth medium for horticulture, and proved to be a suitable and economical substitute for peat moss. Biological tests with mung bean cuttings and Grevillea plantlets showed promotional effects on rooting of the slurry and its sieved fraction extract, washed with water (Capul). Green coffee beans, instant coffee waste, its anaerobically-digested slurry and Capul were extracted by various methods and the extracts were analyzed by TLC, HPLC and GC/MS. Examinations showed clearly the presence of IAA and IBA in free and bound forms in all the substrates. The values of free and bound IAA were calculated by use of an internal standard and GC/MS. The amount of conjugated IAA was found to be much higher than that of free IAA, in both the coffee beans and instant coffee waste (11.1 vs 2.7 nmol g−1, respectively). In the digested slurry and Capul, however, most of the IAA was present as the free form and was approximately 23.5–33.0 nmol g−1, which is almost ten times more than in the waste, and almost twice the total amount of IAA in coffee beans. It is postulated that the high levels of free IAA in the digested instant coffee waste are a result of catabolism of tryptophan by anaerobic bacteria.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Plant growth regulation 13 (1993), S. 179-187 
    ISSN: 1573-5087
    Keywords: Arabidopsis thaliana ; auxin conjugates ; ethylene ; indole-3-acetic acid ; indole-3-butyric acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Indole-3-butyric acid (IBA) was identified by HPLC and GC-MS as an endogenous compound in plantlets of the crucifer Arabidopsis thaliana (L.) Heynh. A. thaliana was cultivated under sterile conditions as shaking culture in different liquid media with and without supply of hormones. Free and total IBA and indole-3-acetic acid (IAA) were determined at different stages of development during the culture period as well as in culture media of different initial pH values. The results showed that IAA was present in higher concentrations than IBA, but both hormones seemed to show the same behaviour under the different experimental conditions. Differences were found in the mode of conjugation of the two hormones. While IAA was mostly conjugated via amide bonds, the main IBA conjugates were ester bound. The ethylene concentration derived from the seedlings, when they were grown in flasks of different size, seemed not to influence the auxin content in the same cultures.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Plant growth regulation 11 (1992), S. 357-362 
    ISSN: 1573-5087
    Keywords: Citrus ; conjugation ; ethylene ; IAA ; IBA ; polar transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Transport and metabolism of radiolabeled indole-3-butyric acid (IBA) were studied in midrib sections of Cleopatra mandarin (Citrus reticulata Blanco) and compared to that of indole-3-acetic acid (IAA). Exogenous IBA was metabolized by the midribs to a polar compound, probably an ester conjugate. Ethylene pretreatment of the midribs reduced their capacity to metabolize IBA by ca. 70% as compared to air pretreatment. IBA transport capacity in the leaf midribs was ca. two times greater in the basipetal direction than the acropetal. The basipetal transport capacity of 3H-IBA was lower than that of 14C-IAA (ca. 24% and 39% of the uptake, respectively). While ethylene treatment reduced basipetal transport of IAA by ca. 70% it did not affect the transport of IBA. Most of the transported label was found as free IBA, but the reduction of IBA conjugation by ethylene treatment did not affect the transport capacity.
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