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At least 91 records · Page 5Linked to original sources
PubMed1992

Studies on the longitudinal and lateral transport of IAA in the shoots of etiolated corn seedlings.

The auxin, indole-3-acetic acid, and the symplastic probe, carboxyfluorescein diacetate, were applied to the cut mesocotyl base or coleoptile apex of etiolated Zea mays seedlings and their transport measured and tissue distribution determined. The longitudinal transport of indole-3-acetate was strongly basipolar, while that of carboxyfluorescein was essentially apolar. The longitudinal transport of IAA, like carboxyfluorescein, was mainly in the stele. IAA exhibited a much higher lateral mobility from stele to cortex than did carboxyfluorescein. Based on the calculation of moles probe/kg fw, IAA is 4 times more concentrated in the stele than in the cortex while CF is 24 times higher in concentration in the stele than in the cortex. The structure of the node and the mesocotyl regions just below the node, regions of maximum growth, were examined and plasmodesmatal structure and frequency in these regions determined. The plasmodesmatal frequency, about 3 per micrometer2, between all cell types of the mesocotyl was found to be about 5-8 fold higher than that found for the root. Hypotheses of lateral auxin transport are discussed.

Biological Transport↗
PubMed1990

Autoantibodies against insulin (IAA), C-peptide (CAA), and glucagon (GAA) in new-onset type 1 diabetic patients.

Autoantibodies against insulin, C-peptide, and glucagon were determined by radio-binding assay in 63 new-onset Type 1 (insulin-dependent) diabetic patients as well as in 70 controls. Plasma peptide binding was determined by means of 125I-labeled peptides and charcoal-dextran separation technique. Binding values exceeding the mean plus three standard deviations of the controls were considered as antibody-positive. Sixteen patients (25%) were positive for IAA, as 6 (10%) were positive for CAA and 2 (3%) for GAA. Of all control subjects, none were positive for either IAA or CAA, whereas 2 (2%) had GAA. The mean 125I-glucagon binding in the patients' group was, however, slightly enhanced and could be suppressed to normal values by excess unlabeled glucagon. The presence of IAA and/or CAA was significantly associated with more severe symptoms at diabetes manifestation. These results indicate that in new-onset Type 1 diabetics autoimmunity arises against all the insular peptides tested but is predominantly directed against those antigens secreted from the beta cells. Nevertheless, extremely low-binding GAA seem to be common in these patients. The determination of IAA/CAA might be useful in detecting a possible heterogeneity of Type 1 diabetes with regard to its clinical mode of manifestation.

Age Factors↗
PubMed2003

Stimulatory effect of cytokinins and interaction with IAA on the release of lateral buds of pea plants from apical dominance.

Lateral buds of pea plants can be released from apical dominance and even be transformed into dominant shoots when repeatedly treated with synthetic exogenous cytokinins (CKs). The mechanism of the effect of CKs, however, is not clear. The results in this work showed that the stimulatory effects of CKs on the growth of lateral buds and the increase in their fresh weights in pea plants depended on the structure and concentration of the CKs used. The effect of N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU) was stronger than that of 6-benzylaminopurine (6-BA). Indoleacetic acid (IAA) concentration in shoot, IAA export out of the treated apex and basipetal transport in stems were markedly increased after the application of CPPU or 6-BA to the apex or the second node of pea plant. This increase was positively correlated with the increased concentration of the applied CKs. These results suggest that the increased IAA synthesis and export induced by CKs application might be responsible for the growth of lateral shoots in intact pea plants.

Adenine↗
PubMed2006

ABP1 expression regulated by IAA and ABA is associated with the cambium periodicity in Eucommia ulmoides Oliv.

A cDNA clone of Eucommia ulmoides Oliv. encoding auxin binding protein 1 (ABP1), one of the putative receptors of auxin, was isolated, and the seasonal expression of ABP1 in relation to IAA and ABA annual variation was investigated by different technical approaches including RT-PCR, real-time PCR, northern blotting, western blotting, and immunolocalization. In the cambial region, ABP1 expression at both the protein and the mRNA level was found to be high, low, and remarkably scarce in the active, quiescent, and resting stages, respectively, during cambium periodicity. The signal abundance of ABP1 follows the opposite pattern to ABA accumulation and correlates with auxin responsiveness of the cambial tissues, suggesting a role for ABP1 in mediating auxin-dependent regulation of cambial activation in the activity-dormancy cycle. This paper attempts to explain why IAA would 'boost' the reactivation of a quiescent cambium, and not that of a resting cambium. Results also show that ABP1 expression is improved by IAA, while inhibited by ABA.

Abscisic Acid↗
PubMed1992

Cloning of a promoter-like soybean DNA sequence responding to IAA induction in Escherichia coli K12.

We have constructed a soybean genomic DNA library in Escherichia coli K12 strain KC13 using plasmid pPV33, which consists of a promoter-less tetracycline resistance (Tcr) gene. A recombinant clone, KC13(pAU-SB1)+, was obtained by selecting for resistance to tetracycline in the presence of indole-3-acetic acid (IAA). Restriction enzyme cleavage and Southern hybridization analysis revealed that the pAU-SB1 plasmid has a 250 bp soybean DNA insert fused with the Tcr gene. In the presence of a selected group of auxins, induction of the Tcr phenotype and mRNA synthesis of the Tcr gene are observed only in KC13(pAU-SB1)+ cultures. On the other hand, induction of the Tcr phenotype and mRNA synthesis of the Tcr gene are absent in cells harboring the cloning vector pPV33 or a recombinant plasmid containing the 250 bp insert in the reverse orientation, pAU-SB1ro. This demonstrated a need for the insertion of the 250 bp soybean DNA and the specificity of its orientation in response to IAA induction. The start point of mRNA transcription in response to IAA, IBA, IPA, 2,4,5-T, and a-NAP is at base pair -96 or -95 upstream of the translational start site of the Tcr gene and base pair -98 with 2,4-D.

Base Sequence↗
PubMed1992

Indole-3-acetic acid (IAA) production by Arthrobacter species isolated from Azolla.

Arthrobacter species, isolated from the leaf cavities and the microsporocarps of the aquatic fern species Azolla pinnata and Azolla filiculoides, produced indole-3-acetic acid (IAA) in culture when the precursor tryptophan was added to the medium. No IAA production was detected in the absence of tryptophan. Maximum IAA formation was obtained in the first 2 d of incubation. Part of the tryptophan was transformed to N alpha-acetyl-L-tryptophan.

Arthrobacter↗
PubMed1986

Comparison of IAA-Induced and Low Temperature-Induced GA(3) Responsiveness and alpha-Amylase Production by GA(3) Insensitive Dwarf Wheat Aleurone.

Rht3-containing gibberellic acid (GA(3)) insensitive deembryonated wheat (Triticum aestivum L. var Cappelle Desprez x Minister Dwarf) aleurone, that can be made responsive to GA(3) by low temperature, can also be rendered GA(3) sensitive by preincubation with indoleacetic acid (IAA). The IAA-induced response of the dwarf selection is concentration-dependent, relatively sensitive, and similar in magnitude to that induced by low temperature. Other auxins also induce GA(3) responsiveness to a greater or lesser degree. IAA has no apparent effect on the wild type (rht, tall) selection.

Journal Article↗
PubMed2006

Production and characterization of auxin-insensitive rice by overexpression of a mutagenized rice IAA protein.

Since auxin was first isolated and characterized as a plant hormone, the underlying molecular mechanism of auxin signaling has been elucidated primarily in dicot plants represented by Arabidopsis. In monocot plants, the molecular mechanism of auxin signaling has remained unclear, despite various physiological experiments. To understand the function and mechanism of auxin signaling in rice (Oryza sativa), we focused on the IAA gene, a well-studied gene in Arabidopsis that serves as a negative regulator of auxin signaling. We found 24 IAA gene family members in the rice genome. OsIAA3 is one of these family members whose expression is rapidly increased in response to auxin. We produced transgenic rice harboring mOsIAA3-GR, which can overproduce mutant OsIAA3 protein containing an amino acid change in domain II to cause a gain-of-function phenotype, by treatment with dexamethasone. The transgenic rice was insensitive to auxin and gravitropic stimuli, and exhibited short leaf blades, reduced crown root formation, and abnormal leaf formation. These results suggest that, in rice, auxin is important for development and its signaling is mediated by IAA genes.

Amidohydrolases↗
PubMed2004

No association of INS-VNTR genotype and IAA autoantibodies.

Type 1 diabetes is associated with autoimmune responses against insulin, with insulin autoantibodies (IAA) being a hallmark of the disease. Genetic susceptibility to type 1 diabetes is polygenic and includes the INS VNTR-IDDM2 locus, which has been shown to regulate the expression of insulin in the pancreas and thymus. In order to determine whether insulin autoimmunity could be attributed to a genetic susceptibility conferred by the INS-VNTR (IDDM2) locus, we studied the frequency of INS-VNTR alleles and the presence of IAA in 90 patients with new-onset type 1 diabetes. IAA were detected in 49 of 67 class I/I individuals and 19 of 23 class III/X patients, indicating that there is no association between the INS VNTR-IDDM2-susceptible allele and humoral autoimmunity against insulin. This finding does not support the hypothesis of an allele-specific tolerance induction that could determine susceptibility toward autoimmunity against the insulin protein and subsequently the development of type 1 diabetes.

Adolescent↗
PubMedDate not supplied

[Effect of IAA on the photophosphorylation of pea isolated chloroplasts].

Effect of IAA (10(-10)-10(-3) M) on photophosphorylation, NADP reduction and the oxygen exchange is investigated. It is shown that low concentrations of IAA (10(-10)-10(-7) M) increase the photophosphorylation reaction and the flow of electrones to NADP under the phosphorylation conditions in the chloroplasts, and their effect on the O2 exchange is not the same in different types of photophosphorylation. It is supposed that the effect of IAA on the photophosphorylation is connected with H292 metabolism in chloroplasts and with catalase and peroxidase functions.

Chloroplasts↗
PubMed1994

IAA synergism and vitamin B1 antagonism with calcium for induction and growth of adventitious roots in branch cuttings of Dalbergia sissoo Roxb.

IAA induced adventitious roots in branch cuttings of D. sissoo, whereas vit. B1 promoted growth of these roots. A strong IAA synergism and vit. B1 antagonism with calcium was observed in induction and growth of adventitious roots. Treatments with IAA (571 microM) and calcium (134 microM) proved to be an ideal combination, exhibiting 87% rooting and 0.87 R/S ratio in branch cuttings, coupled with an increase of root length, root number, root fresh weight and root dry weight as compared to control.

Calcium↗
PubMed1993

Characterization of an insertion sequence (IS53) located within IS51 on the iaa-containing plasmid of Pseudomonas syringae pv. savastanoi.

A 2568-base pair (bp) insertion sequence (IS53) was cloned from the iaa-containing plasmid pIAA2 of Pseudomonas syringae subsp. savastanoi. IS53 is located downstream from the iaa operon and is inserted into IS51, a previously described element on pIAA2. IS53 causes an 8-bp target duplication and has nearly perfect terminal inverted repeats of 27 bp. Several degenerate copies of the inverted repeats are located internal, and in direct orientation to the terminal inverted repeats. A putative transposase gene conforms to the transposase ORF/opposite strand overlapping ORF motif described in many gram-negative IS elements. The region 5' to the presumptive transposase gene contains sequences that are homologous to the consensus E. coli heat-shock (sigma 32) promoter.

Amino Acid Sequence↗
PubMed1991

Sequence of the iaa and ipt region of different Agrobacterium tumefaciens biotype III octopine strains: reconstruction of octopine Ti plasmid evolution.

The TA regions of biotype III octopine/cucumopine (OC) Ti plasmids are closely related to the TL region of the biotype I octopine Ti plasmids pTiAch5 and pTi15955. Sequence analysis shows that the limited and wide host range biotype III OC TA regions are derived from a common ancestor structure which lacked the 6a gene found in the biotype I octopine TL region. The TA region of the wide host range OC Ti plasmids has conserved most of the original TL-like structure. In most wide host range OC isolates the TA-iaaH gene is inactivated by the insertion of an IS866 element. However, the TA region of the wide host range isolate Hm1 carries an intact TA-iaaH gene. This gene encodes a biologically active product, as shown by root induction tests and indole-3-acetic acid measurements. The limited host range OC Ti plasmids pTiAB3 and pTiAg57 have shorter TA regions which are derived from a wide host range TA region. The AB3 type arose by an IS868-mediated, internal TA region deletion which removed the iaa genes and part of the ipt gene and left a copy of IS868 at the position of the deleted fragment. The pTiAB3 iaa/ipt deletion was followed by insertion of a second IS element, IS869, immediately 3' of the ipt gene. pTiAg57 underwent the same iaa-ipt deletion as pTiAB3, but lacks the IS868 and IS869 elements. Analysis of the various TA region structures provides a detailed insight into the evolution of the biotype III OC strains.

Amino Acid Sequence↗
PubMed2001

Effects of salinity on endogenous ABA, IAA, JA, AND SA in Iris hexagona.

Phytohormones play critical roles in regulating plant responses to stress. We investigated the effects of salinity on abscisic acid (ABA), indole-3-acetic acid (IAA), salicylic acid (SA), and jasmonic acid (JA) in leaves, stalks, fruits, and seeds of Iris hexagona, a native wetland species. Using gas chromatography-mass spectroscopy with selected ion monitoring, our experiments demonstrated significant and different short- and long-term changes in iris phytohormones. ABA and JA generally increased and IAA and SA declined in response to salinity. We conclude that these phytohormones may have separate and interactive effects on how plants respond and adapt to stress in natural environments.

Abscisic Acid↗
PubMed2000

[Immunocytological localization of IAA in the parenchyma cell and vascular elements in the graft union of Cucurbita pepo/Cucurbita moschata at the early developmental stage].

Immuno-gold localization of IAA in cells of the graft union in the explant internode graft of Cucurbita pepo/Cucurbita moschata were investigated with electron microscopy. In parenchyma cells near the graft union, the gold particles were mainly accumulated in nucleus, plastid and endoplasmic reticulum, while no gold particles was detected in Golgi body, mitochondrion, cell wall and vacuoles. In the differentiating xylem element, the gold particles were labeled in secondary wall and cytoplasm. In the sieve element gold particles were found in the sieve plate, sieve pore and cytoplasm. There was a dense label of the gold particles in the companion cell. The role of IAA in the differentiation of the vascular elements was discussed.

Cucurbita↗
PubMed1995

[Bypass grafting of left subclavian artery to descending thoracic aorta for relative stenosis of bypass graft after total correction for type A IAA with VSD].

A 4-year-old child underwent one-stage total correction for type A IAA with VSD in 1975 as the first successful case in Japan. At age 21, a gradual rise in her upper limb pressure to 190 mmHg prompted repeat catheterization, which showed a pressure gradient across the EPTFE graft of 58 mmHg. Under general anesthesia in the right lateral position, the patient's left thorax was reopened. The EPTFE graft had undergone patchy calcific degeneration and was significantly hardened. An 18-mm Toray graft preclotted with fibrin glue was anastomosed to the left subclavian artery in side-to-end fashion. Its distal end was anastomosed to the descending aorta distal to the EPTFE bypass during a 20-minute aortic occlusion. The postoperative recovery was uneventful and the pressure gradient between the upper and lower limbs fell to 0 at discharge. We chose this method for reoperation of type A IAA and CoA because of the reduced need for dissection and better effectiveness.

Adult↗
PubMed1996

Determination of IAA in brassinolide treated coleoptiles of wheat by a modified indirect ELISA with polyclonal antibodies.

An indirect enzyme immunoassay for detection of as little as 10-50 pmole IAA is described for the first time. The assay is based on the development of highly specific polyclonal antibodies against the carboxyl site of IAA. The binding specificity is nearly as high as the radioimmunoassay and the titre of the specific antibody was also remarkably high (1:40,000 of the primary antibody). Such an easy, rapid, specific and highly sensitive assay would be extremely useful in gaining more information on the mode of action of phytohormones, and their effects on physiological processes.

Animals↗