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1.
A sensitive enzyme-immunoassay was developed to quantify the tulip lectin and used to follow its distribution during the life cycle of tulips cv. Attila.The tulip lectin is predominantly located in the bulbs. At planting time the absolute lectin concentration is approximately the same in all bulb scales. However, as the shoot grows and the plant turns on to flowering, the lectin concentration rapidly decreases, first in the inner bulb scales but later also in the outer bulb scale. Soon after flowering the lectin rapidly accumulates in the new daughter bulbs.Lectin levels in leaves, stems and flowers are very low. The lectin in these tissues is already present before the sprout emerges. During the first two weeks after planting, there is a small increase in lectin concentration, followed by a rapid decrease as the plant turns on to flowering. By flowering time all the lectin has disappeared from the aerial parts.Abbreviations DW
dry weight
- ELISA
enzyme-linked immunosorbent assay
- FW
fresh weight
- PBS
phosphate-buffered saline
- PBSN
phosphate-buffered saline containing 0.02% sodium azide
- PBST
phosphate-buffered saline containing 0.02% sodium azide and 0.05% Tween 20
- TL
tulip lectin
- Tris
2-amino-2-(hydroxymethyl)-1,3-propanediol 相似文献
2.
Willy J Peumans Harry C Winter Veronique Bemer Fred Van Leuven Irwin J Goldstein Paolo Truffa-Bachi Els J.M Van Damme 《Glycoconjugate journal》1997,14(2):259-265
A novel plant lectin has been isolated from the rhizomes of Calystegia sepium (hedge bindweed) and partially characterized. The lectin is a dimeric protein composed of two identical non-covalently linked
subunits of 16kDa. Hapten inhibition studies indicate that the novel lectin is best inhibited by maltose and mannose and hence
exhibits a sugar binding specificity that differs in some respects from that of all previously isolated plant lectins. Mitogenicity
tests have shown that the Calystegia lectin is a powerful T-cell mitogen. Affinity purification of human, plant and fungal glycoproteins on immobilized C. sepium lectin demonstrates that this novel lectin can be used for the isolation of glycoconjugates from various sources. Moreover,
it can be expected that by virtue of its distinct specificity, the new lectin will become an important tool in glycobiology.
Abbreviations: Calsepa, lectin isolated from Calystegia sepium; ConA, concanavalin A; LPS, lipopolysaccharide; PBS, phosphate
buffered saline (1.5 mMKH2PO4, 10 mM Na2HPO4, 3 mM KCl, 140 mM NaCl, pH 7.4)
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
3.
cDNA cloning, primary structure, and in vitro biosynthesis of the DB58 lectin from Dolichos biflorus 总被引:1,自引:0,他引:1
Previous studies have shown that the Dolichos biflorus plant contains a lectin in its stems and leaves, called DB58, that is closely related to the D. biflorus seed lectin. DB58 is a heterodimer composed of two closely related subunits. Immunoprecipitation of total translation products from D. biflorus stem and leaf mRNA suggests a single polypeptide precursor for both of these subunits. Several identical cDNA clones representing the entire coding region of the DB58 mRNA have been isolated from a D. biflorus stem and leaf cDNA library. The DB58 cDNA represents an mRNA encoding a polypeptide of Mr = 29,545. The predicted polypeptide is equal in length to the larger subunit of DB58 with the addition of a 22-amino acid amino-terminal signal sequence. The sequence of the DB58 lectin exhibits 84% homology to the D. biflorus seed lectin at the amino acid level, suggesting that these lectins are encoded by differentially expressed genes and may have evolved to carry out tissue-specific functions. Comparison of the DB58 sequence to other leguminous seed lectins indicates a high degree of structural conservation. 相似文献
4.
Root lectins are believed to participate in the recognition between Rhizobium and its leguminous host plant. Among other factors, testing this hypothesis is difficult because of the very low amounts in which root lectins are produced. A double-antibody-sandwich enzyme-linked immunoassay, was used to determine nanogram quantities of pea lectin in root slime and salt extracts of root cell-wall material when pea seedlings were 4 and 7 d old. In addition, a critical NO
3
-
concentration (20 mM) which inhibited nodulation was found, and the lectin present in root slime and salt extracts of root cell walls of 4- and 7-d-old peas supplied with 20 mM NO
3
-
was comparatively determined. With the enzyme-linked immunoassay, lectin quantities ranging between 20 and 100 nanograms could be determined. The assay is not affected by monomeric mannose and glucose (pealectin haptens). The slime of the 4-d-old roots contained more lectin than the slime of the 7-d-old roots. Salt-extractable, cell-wall-associated lectin accumulated in the older roots. Nitrate affected slime and cell-wall production, and the extractability of cell-wall material in both age groups. The presence of NO
3
-
increased lectin in the slime, most notably in the younger roots; the relative amount of lectin in the slime was almost doubled. The cell-wall-associated, salt-extractable lectin decreased two- to threefold compared with the control group.Abbreviations ELISA
enzyme-linked immunoassay
- PTN
0.01 M phosphate buffer (pH 7.4), containing 0.15 M NaCl, 0.05% Tween-20 and 0.02% NaN3
Dedicated to Professor A. Quispel on the occasion of his retirement 相似文献
5.
Liquid-liquid extraction of lectin from Cratylia mollis seeds using reversed micelles 总被引:1,自引:0,他引:1
C.O. Nascimento L.C.B.B. Coelho M.T.S. Correia M.G. Carneiro-da-Cunha 《Biotechnology letters》2002,24(11):905-907
Extraction of lectin from seeds ofCratylia mollis, camaratu bean, with reversed micelles of 100 mM sodium di(2-ethylhexyl) sulfosuccinate/isooctane was performed firstly with affinity-purified lectin. The best conditions were extraction of the seed extract at pH 5 and back-extraction at pH 10, giving yields of 38% and 100%, respectively. 相似文献
6.
Konozy EH Bernardes ES Rosa C Faca V Greene LJ Ward RJ 《Archives of biochemistry and biophysics》2003,410(2):222-229
A lectin was isolated from the saline extract of Erythrina speciosa seeds by affinity chromatography on lactose-Sepharose. The lectin content was about 265 mg/100g dry flour. E. speciosa seed lectin (EspecL) agglutinated all human RBC types, showing no human blood group specificity; however a slight preference toward the O blood group was evident. The lectin also agglutinated rabbit, sheep, and mouse blood cells and showed no effect on horse erythrocytes. Lactose was the most potent inhibitor of EspecL hemagglutinating activity (minimal inhibitory concentration (MIC)=0.25 mM) followed by N-acetyllactosamine, MIC=0.5mM, and then p-nitrophenyl alpha-galactopyranoside, MIC=2 mM. The lectin was a glycoprotein with a neutral carbohydrate content of 5.5% and had two pI values of 5.8 and 6.1 and E(1%)(1 cm) of 14.5. The native molecular mass of the lectin detected by hydrodynamic light scattering was 58 kDa and when examined by mass spectroscopy and SDS-PAGE it was found to be composed of two identical subunits of molecular mass of 27.6 kDa. The amino acid composition of the lectin revealed that it was rich in acidic and hydroxyl amino acids, contained a lesser amount of methionine, and totally lacked cysteine. The N-terminal of the lectin shared major similarities with other reported Erythrina lectins. The lectin was a metaloprotein that needed both Ca(2+) and Mn(2+) ions for its activity. Removal of these metals by EDTA rendered the lectin inactive whereas their addition restored the activity. EspecL was acidic pH sensitive and totally lost its activity when incubated with all pH values between pH 3 and pH 6. Above pH 6 and to pH 9.6 there was no effect on the lectin activity. At 65 degrees C for more than 90 min the lectin was fairly stable; however, when heated at 70 degrees C for 10 min it lost more than 80% of its original activity and was totally inactivated at 80 degrees C for less than 10 min. Fluorescence studies of EspecL indicated that tryptophan residues were present in a highly hydrophobic environment, and binding of lactose to EspecL neither quenched tryptophan fluorescence nor altered lambda(max) position. Treating purified EspecL with NBS an affinity-modifying reagent specific for tryptophan totally inactivated the lectin with total modification of three tryptophan residues. Of these residues only the third modified residue seemed to play a crucial role in the lectin activity. Addition of lactose to the assay medium did not provide protection against NBS modification which indicated that tryptophan might not be directly involved in the binding of haptenic sugar D-galactose. Modification of tyrosine with N-acetylimidazole led to a 50% drop in EspecL activity with concomitant acetylation of six tyrosine residues. The secondary structure of EspecL as studied by circular dichroism was found to be a typical beta-pleated-sheet structure which is comparable to the CD structure of Erythrina corallodendron lectin. Binding of lactose did not alter the EspecL secondary structure as revealed by CD examination. 相似文献
7.
8.
Two lectins were purified by affinity chromatography from mature peanut (Arachis hypogaea L.) nodules, and compared with the previously characterised seed lectin of this plant. One of the nodule lectins was similar to the seed lectin in its molecular weight and amino-acid composition and ability to bind derivatives of galactose. However, unlike the seed lectin, this nodule lectin appeared to be a glycoprotein and the two lectins were only partially identical in their reaction with antibodies prepared against the seed lectin. The other nodule lectin also appeared to be a glycoprotein but bound mannose/glucose-like sugar derivatives, and differed from the seed lectin in molecular weight, antigenic properties and amino-acid composition.Abbreviations Gal
galactose
- Gle
glucose
- GNL
galactose-binding nodule lectin
- Fru
fructose
- MNL
mannosebinding nodule lectin
-
M
r
rerative molecular mass
- PBS
phosphate-buffered saline
- PSL
peanut seed lectin
- SDS
sodium dodecyl sulphate
- Sorb
sorbitol 相似文献
9.
We have examined the properties and subcellular localization of phytohemagglutinin (PHA), the major lectin of the common bean (Phaseolus vulgaris.), in the axis cells of nearly mature and imbibed mature seeds. On a protein basis the axis contained about 15% as much PHA as the cotyledons. Localization of PHA was done with an indirect immunolabeling method (rabbit antibodies against PHA, followed by colloidal gold particles coated with goat antibodies against rabbit immunoglobulins) on ultra-thin cryosections which were embedded in plastic on the grids after the immunolabeling procedure. The embedding greatly improved the visualization of the subcellular structures. The small (4 nm) collodial gold particles, localized with the electron microscope, were found exclusively over small vacuoles or protein bodies in all the cell types examined (cortical parenchyma cells, vascular-bundle cells, epidermal cells). The matrix of these vacuoles-protein bodies appears considerably less dense than that of the protein bodies in the cotyledons, but the results confirm that in all parts of the embryo PHA is localized in similar structures.Abbreviations IgG
immunoglobulin G
- Mr
relative molecular weight
- PBS
phosphate-buffered saline
- PHA
phytohemagglutinin
- SDS-PAGE
sodium dodecyl sulfate polyacrylamide gel electrophoresis 相似文献
10.
C. L. Díaz M. Hosselet G. J. J. Logman E. van Driessche B. J. J. Lugtenberg J. W. Kijne 《Planta》1990,181(4):451-461
We report on the distribution and initial characterization of glucose/mannose-specific isolectins of 4- and 7-d-old pea (Pisum sativum L.) seedlings grown with or without nitrate supply. Particular attention was payed to root lectin, which probably functions as a determinant of host-plant specificity during the infection of pea roots by Rhizobium leguminosarum bv. viciae. A pair of seedling cotyledons yielded 545±49 g of affinity-purified lectin, approx. 25% more lectin than did dry seeds. Shoots and roots of 4-d-old seedlings contained 100-fold less lectin than cotyledons, whereas only traces of lectin could be found in shoots and roots from 7-d-old seedlings. Polypeptides with a subunit structure similar to the precursor of the pea seed lectin could be demonstrated in cotyledons, shoots and roots. Chromatofocusing and isoelectric focusing showed that seed and non-seed isolectin differ in composition. An isolectin with an isoelectric point at pH 7.2 appeared to be a typical pea seed isolectin, whereas an isolectin focusing at pH 6.1 was the major non-seed lectin. The latter isolectin was also found in root cell-wall extracts, detached root hairs and root-surface washings. All non-seed isolectins were cross-reactive with rabbit antiserum raised against the seed isolectin with an isolectric point at pH 6.1. A protein similar to this acidic glucose/mannose-specific seed isolectin possibly represents the major lectin to be encountered by Rhizobium leguminosarum bv. viciae in the pea rhizosphere and at the root surface. Growth of pea seedlings in a nitrate-rich medium neither affected the distribution of isolectins nor their hemagglutination activity; however, the yield of affinity-purified root lectin was significantly reduced whereas shoot lectin yield slightly increased. Agglutination-inhibition tests demonstrated an overall similar sugar-binding specificity for pea seed and non-seed lectin. However root lectin from seedlings grown with or without nitrate supplement, and shoot lectin from nitrate-supplied seedlings showed a slightly different spectrum of sugar binding. The absorption spectra obtained by circular dichroism of seed and root lectin in the presence of a hapten also differed. These data indicate that nutritional conditions may affect the sugar-binding activity of non-seed isolectin, and that despite their similarities, seed and non-seed isolectins have different properties that may reflect tissue-specialization.Abbreviations IEF
isoelectric focusing
- MW
molecular weight
- pI
isoelectric point
- Psl1, Psl2 and Psl3
pea isolectins
- SDSPAGE
sodium dodecyl sulfate polyacrylamide gel electrophoresis
The authors wish to thank Professors L. Kanarek and M. van Poucke for helpful discussions. 相似文献
11.
Jong Won Han Min Gui Jung Min Jung Kim Kang Sup Yoon Key Pyoung Lee Gwang Hoon Kim 《Phycological Research》2010,58(2):143-150
A d ‐mannose specific lectin was purified from the green marine alga, Bryopsis plumosa (Huds.) Ag. The lectin agglutinated horse and sheep erythrocytes. Matrix assisted laser desorption/ionization time of flight mass spectrometry, size exclusion chromatography, sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) and two dimensional gel electrophoresis (2DE) results showed that the lectin was a monomer with molecular weight of 17 kDa and pI 7.3. The agglutinating activity was inhibited by d ‐mannose (1 mM), α‐methyl‐D‐mannose (4 mM) and l ‐fucose (8 mM). d ‐glucose (125 mM) showed weak inhibition. The lectin did not need divalent cations for agglutinating activity. N‐terminal amino acid sequence of the lectin was analyzed. As the lectin was novel, we named it BPL‐2 (Bryopsis plumosa lectin 2). Full cDNA sequence of BPL‐2 was obtained using cDNA library. It was comprised of 624 bp of open reading frame and 167 bp/57 bp of 3′/5′ untranslated regions as well as N‐terminal signal peptide. No antimicrobial activity of BPL‐2 was observed in four bacteria strains tested. 相似文献
12.
Carl A. K. Borrebaeck 《Planta》1984,161(3):223-228
The distribution of lectin in various tissues ofPhaseolus vulgaris L. (cv. red) has been investigated using a sensitive solid-phase enzyme immunoassay. Roots, leaves and stems from 3- to 4-week-old plants were screened for their lectin content; low levels could be detected in all organs, with a relative distribution of 37% in roots, 20% in leaves and 43% in stems. The lectin from stemsleaves and roots was then isolated from 5- to 6-week-old plants using extraction, salt fractionation and affinity chromatography on immobilized porcine thyroglobulin. A comparative study of the seed lectin and the lectin isolated from 5- to 6-week-old plants was made using hemagglutination, inhibition of hemagglutination, immunodiffusion, polyacrylamide and agarose electrophoresis. The results showed that lectin isolated from the different tissues was immunologically identical and exhibited the same subunit structure and similar isolectin composition as the seed lectin.Abbreviations EDTA
ethylenediaminetetraacetic acid
- PHA
phytohemagglutinin
- SDS
sodium dodecyl sulfate 相似文献
13.
Antibodies were raised against lectin purified from the sieve-tube exudate of Cucurbita maxima. Immunocytochemistry, using peroxidase-labelled antibodies and Protein A-colloidal gold, was employed to determine the location of the lectin within the tissues and cells of C. maxima and other cucurbit species. The anti-lectin antibodies bound to P-protein aggregates in sieve elements and companion cells, predominantly in the extrafascicular phloem of C. maxima. This may reflect the low rate of translocation in these cells. Under the electron microscope, the lectin was shown to be a component of P-protein filaments and was also found in association with the sieve-tube reticulum which lines the plasmalemma. The anti-lectin antibodies reacted with sieve-tube proteins from other species of the genus Cucurbita but showed only limited reaction with other genera. We suggest that the lectin serves to anchor P-protein filaments and associated proteins to the parietal layer of sieve elements.Abbreviation SDS-PAGE
sodium dodecyl sulphate-polyacrylamide gel electrophoresis 相似文献
14.
A sensitive immunosorbent assay was developed to quantify the lectin in different tissues ofGalanthus nivalis (snowdrop) andNarcissus cv. Carlton (daffodil) and follow the distribution of the lectin during the life cycle of the plants. The lectin in snowdrops
and daffodils occurs in almost all plant tissues. Moreover, in many tissues the lectin is the most prominent protein. High
lectin concentrations are found in the bulb where the lectin accounts for up to 15% of the total protein during the resting
period. However, as the shoot grows and the plant turns on to flowering the lectin content rapidly decreases. Soon after flowering
the lectin accumulates in the new bulb units. Whereas in daffodil the lectin concentration in the aerial plant parts is about
one order of magnitude lower than in the bulb, lectin concentrations in the upper parts of snowdrop are similar to those in
the bulb. The lectin in the former tissues is already present before the sprout emerges. As the shoot starts to grow lectin
concentrations in leaves, stems and flower parts gradually decrease so that at flowering time virtually all lectin has disappeared
from the aerial parts. The highest lectin concentrations are found in the ovary and increase, initially, as the sprout emerges
from the bulb.
This work was supported in part by grants from the ‘Nationale Bank’ and the National Fund for Scientific Research (Belgium).
W.J.P. is a Senior Research Associate and E.J.M.V.D. Research Assistant of this fund. 相似文献
15.
白桦茸凝集素提取工艺的优化 总被引:1,自引:0,他引:1
对白桦茸凝集素最佳提取工艺进行了研究.以2%兔血细胞凝血效价为指标,确定了最佳提取缓冲液.通过正交试验对料液比、提取时间、提取液pH值、NaCl浓度等因素进行了优化分析并确定了提取工艺的最佳参数组合.结果表明,以TBS和PBS为提取缓冲液所得的白桦茸凝集素凝集效价分别为64、16;最佳提取工艺:液料比为50:1,提取时间为20h,NaCl浓度为0mol/L,缓冲液pH值为8.0,按该最佳工艺提取白桦茸凝集素凝血效价为256.所优化的提取工艺稳定、可行,为该凝集素进一步在免疫调节方面的开发应用提供一定基础. 相似文献
16.
Yukiko Konami Kazuo Yamamoto Toshiaki Osawa Tatsuro Irimura 《Glycoconjugate journal》1995,12(2):128-134
The complete amino acid sequence of a lactose-bindingCytisus sessilifolius anti-H(O) lectin II (CSA-II) was determined using a protein sequencer. After digestion of CSA-II with endoproteinase Lys-C or Asp-N, the resulting peptides were purified by reversed-phase high performance liquid chromatography (HPLC) and then subjected to sequence analysis. Comparison of the complete amino acid sequence of CSA-II with the sequences of other leguminous seed lectins revealed regions of extensive homology. The amino acid sequence of a putative carbohydrate-binding domain of CSA-II was found to be similar to those of several anti-H(O) leguminous lectins, especially to that of thel-fucose-bindingUlex europaeus lectin I (UEA-I).Abbreviations BPA
Bauhinia purpurea lectin
- Con A
concanavalin A
- CMA-I
Cytisus multiflorus lectin I
- CMA-II
Cytisus multiflorus lectin II
- CSA-I
Cytisus sessilifolius lectin I
- CSA-II
Cytisus sessilifolius lectin II
- CSII
Cytisus scoparius lectin II
- ECorL
Erythrina corallodendron lectin
- GSIV
Griffonia simplicifolia lectin IV
- HPLC
high performance liquid chromatography
- LAA-I
Laburnum alpinum lectin I
- LAA-II
Laburnum alpinum lectin II
- LOL
Lathyrus ochrus lectin
- LTA
Lotus tetragonolobus lectin
- MAH
Maackia amurensis haemagglutinin
- PSA
Pisum sativum lectin
- SDS
sodium dodecyl sulfate
- TFA
trifluoroacetic acid
- UEA-I
Ulex europaeus lectin I
- UEA-II
Ulex europaeus lectin II
- VFA
Vicia faba lectin 相似文献
17.
Buts L Dao-Thi MH Loris R Wyns L Etzler M Hamelryck T 《Journal of molecular biology》2001,309(1):193-201
The legume lectins are widely used as a model system for studying protein-carbohydrate and protein-protein interactions. They exhibit a fascinating quaternary structure variation, which becomes important when they interact with multivalent glycoconjugates, for instance those on cell surfaces. Recently, it has become clear that certain lectins form weakly associated oligomers. This phenomenon may play a role in the regulation of receptor crosslinking and subsequent signal transduction. The crystal structure of DB58, a dimeric lectin from the legume Dolichos biflorus reveals a separate dimer of a previously unobserved type, in addition to a tetramer consisting of two such dimers. This tetramer resembles that formed by DBL, the seed lectin from the same plant. A single amino acid substitution in DB58 affects the conformation and flexibility of a loop in the canonical dimer interface. This disrupts the formation of a stable DBL-like tetramer in solution, but does not prohibit its formation in suitable conditions, which greatly increases the possibilities for the cross-linking of multivalent ligands. The non-canonical DB58 dimer has a buried symmetrical alpha helix, which can be present in the crystal in either of two antiparallel orientations. Two existing structures and datasets for lectins with similar quaternary structures were reconsidered. A central alpha helix could be observed in the soybean lectin, but not in the leucoagglutinating lectin from Phaseolus vulgaris. The relative position and orientation of the carbohydrate-binding sites in the DB58 dimer may affect its ability to crosslink mulitivalent ligands, compared to the other legume lectin dimers. 相似文献
18.
In-vivo synthesis of the white-clover lectin, trifoliin A, was examined by the incorporation of labeled amino acids into protein during heterotrophic growth of intact Trifolium repens L. seedlings. Lectin synthesis was quantified by measuring the level of labeled protein immunoprecipitated from root exudate, from the hapten (2-deoxyglucose) eluate of the roots, and from root and shoot homogenates. The presence of labeled trifoliin A was confirmed by non-denaturing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by fluorography and comparison with trifoliin A standards. In-vivo-labeled trifoliin A was detected in seedling root homogenate 2 h after the addition of labeled amino acids and on the root surface by 8 h. Incorporation of labeled amino acids into protein and trifoliin A was greatest with 2-d-old seedlings and was greater when the plants were grown continuously in the dark than when they were exposed to 14 h light daily. Significantly more labeled lectin accumulated on the root surface of seedlings grown with 1.5 mM KNO3 than of seedlings grown either without N or with 15.0 mM KNO3. The labeled lectin from the root surface in all nitrate treatments and from the rootexudate samples of seedlings grown N-free and with 1.5 mM KNO3 was fully able to bind to Rhizobium trifolii. In contrast, only 2% of the immunoprecipitable protein found in the root exudate of seedlings grown with 15.0 mM KNO3 was able to bind to the bacteria. Thus, excess nitrate does not repress the synthesis of trifoliin A in the root, but does affect the distribution and activity of this newly synthesized lectin in a way which reduces its ability to interact with R. trifolii. By using Western blot analysis, much more total trifoliin A is detected in the homogenates of shoots than roots. However, greater than 80% of the total labeled protein and 85–90% of the total labeled lectin were found in the root homogenates of 2-d-old dark-grown seedlings incubated for 5 h with labeled amino acids. In addition, Western blot analysis indicated that the shoot homogenate contained smaller-molecular-weight peptides which reacted with the specific anti-trifoliin A antibody. These studies indicate that stored trifoliin A in the seed is degraded in the shoots during seedling development, while newly synthesized trifoliin A in the roots is excreted to the root surface and external environment.Abbreviations IgG
immunoglobulin G
- LPS
lipopolysaccharide
- PBS
10 mM potassium-phosphate buffer, pH 7.0, containing 0.8% NaCl
- PBS-T
20 mM phosphate-buffered saline, pH 7.4, containing 0.05% Tween 20
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide gel electrophoresis 相似文献
19.
The direct double-antibody enzymelinked immunosorbent assay system was used in the detection and measurement of seed lectins from peanut (Arachis hypogaea L.) and soybean (Glycine max L.) plants (PSL and SBL, respectively) that had been inoculated with their respective rhizobia. Concentrations of PSL dropped to undetectable levels in peanut roots at 9 d and stems and leaves at 27 d after planting; SBL could no longer be detected in soybean roots at 9 d and in stems and leaves at 12 d. A lectin antigenically similar to PSL was first detected in root nodules of peanuts at 21 d reaching a maximum of 8 g/g at 29 d then decreasing to 2.5 g/g at 60 d. There was no evidence of a corresponding lectin in soybean nodules.Sugar haemagglutination inhibition tests with neuraminidase-treated human blood cells established that PSL and the peanut nodule lectin were both galactose/lactose-specific. Further tests with rabbit blood cells demonstrated a second mannosespecific lectin in peanut nodule extracts that was not detected in root extracts of four-week-old inoculated plants or six-week-old uninoculated plants, although six-week-old root extracts from inoculated plants showed weak lectin activity. The root extracts from both nodulated and uninoculated plants contained another peanut lectin that agglutinated rabbit but not human blood cells. Haemagglutination by this lectin was, however, not inhibited by simple sugars but a glycoprotein, asialothyroglobulin, was effective in this respect.Abbreviations DAS
double antibody sandwich
- ELISA
enzyme-linked immunosorbent assay
- PBS
phosphate-buffered saline
- PSL
peanut seed lectin
- SBL
soybean lectin 相似文献
20.
A new mannose-binding lectin was isolated from Sternbergia lutea bulbs by affinity chromatography on an α(1-2)mannobiose-Synsorb column and purified further by gel filtration. This lectin
(S. lutea agglutinin; SLA) appeared homogeneous by native-gel electrophoresis at pH 4.3, gel filtration chromatography on a Sephadex
G-75 column, and SDS-polyacrylamide gel electrophoresis, These data indicate that SLA is a dimeric protein (20 kDa) composed
of two identical subunits of 10 kDa which are linked by non-covalent interactions.
The carbohydrate binding specificity of the lectin was investigated by quantitative precipitation and hapten inhibition assays.
It is an α-D-mannose-specific lectin that interacts to form precipitates with various α-mannans, galactomannan and asialo-thyroglobulin,
but not with α-glucans and thyroglobulin. Of the monosaccharides tested only D-mannose was a hapten inhibitor of the SLA-asialothryroglobulin
precipitation system, whereas D-glucose, D-galactose and L-arabinose were not. The lectin appears to be highly specific for
terminal α(1-3)-mannooligosaccharides. The primary structure of SLA appears to be quite similar to that of the snow drop (Galanthus nivalis) bulb lectin which is a mannose-binding lectin from the same plant family Amaryllidaceae. The N-terminal 46 amino acid sequence
SLA showed 7% homology with that of GNA. Abbreviations: AAA, Allium ascalonicum agglutinin (shallot lectin); ASA, Allium sativum
agglutinin (garlic lectin); AUA, Allium ursinum agglutinin (ramsons lectin); DAP, 1,3-diaminopropane; GNA, Galanthus nivalis
agglutinin (snowdrop lectin); HHA, Hippeastrum hybr. agglutinin (amaryllis lectin); LOA, Listera ovata agglutinin (orchid
twayblade lectin); NPA, Narcissus pseudonarcissus agglutinin (daffodil lectin); PAGE, polyacrylamide gel electrophoresis;
PBS, phosphate-buffered saline, SLA, Sternbergia lutea agglutinin; SDS, sodium dodecyl sulfate; Me, methyl; Bn, benzyl; PNP,
p-nitrophenyl.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献