Photocontrol of Dark Circadian Rhythms in Stomata of Phaseolus vulgaris L

Stomatal diffusion resistance in primary leaves of Phaseolus vulgaris L. which had been grown in light:dark cycles followed a marked circadian rhythm when the plants were transferred to continuous darkness. Reentrainment of the rhythm required more than one inductive change in photoperiod. The phasing of the rhythm of dark stomatal opening was contolled primarily by the light-on (dawn) signal, whereas the rhythm of dark closure was related to the light-off (dusk) signal. The evidence points to a dual control of the circadian clock in which a product of photosynthesis plays a major role. No evidence for phytochrome involvement in the phasing of the rhythm was found. An influence of phytochrome on the amplitude of the stomatal rhythm was observed in which removal of phytochrome-far-red absorbing form caused rapid damping.     

Purification and properties of cellulase from Phaseolus vulgaris

Cotyledons of germinating kidney beans contain two forms of a carboxy methyl cellulase which can be separated by ammonium sulfate fractionation and isoelectric focusing. The two cellulases are similar in their molecular weight but differ in isoelectric points, pH and temperature optimum, pH and temperature stability and sensitivity to thiol inhibitors and metal ions. One cellulase (isoelectric point 4.8) has been purified 100-fold to give a major protein band on acrylamide gel electrophoresis.     

Cytokinin Binding Proteins from Phaseolus vulgaris Hypocotyls

t-Zeatin (t-Z) and isopentenyladenosine (iPA) occur naturally as highly active plant cell division regulators, t-Z-Sepherose-4B and iPA-Sepherose-4B affinity column were constructed to isolate and purify the cytokinin-binding proteins from etiolated hypocotyl of Phaseolus vulgaris. Two kinds of cytokinin-binding proteins were obtained. One was 15.5 kD in molecular weight (named ZBP) with only one peptide. The other (named IBP), 165 kD in molecular weight, contained two different subunits (40 kD and 43 kD respectively). The binding activity of ZBP was tested and the dissociation constant (Kd) was determined to be 3.2 × 10-7 mol/L. There was one binding site for t-Z in each molecule of ZBP.     

Linkage Analysis of Hydroxyproline-poor Glycoprotein from Phaseolus vulgaris

Hydroxyproline-poor glycoprotein contains a single polypeptide chain with lysine at the N-terminus. Removal of carbohydrate attached to serine by alkali treatment produces two polypeptide fractions. Labeling with ³⁵S indicates that most serine residues having a carbohydrate substituent removed by alkali occur on the polypeptide fraction of lower molecular weight. Following alkali treatment, two additional N-terminal amino acids, proline and glycine, were detected suggesting that alkali treatment also cleaves peptide bonds. Methylation analysis of native and degraded glycoproteins, extracted 24, 27, and 36 hours after wounding, demonstrates the following structural features of carbohydrate attached to serine. Arabinose may be (1 → 2)-, (1 → 3)-, or (1 → 5)-linked, glucose occurs as a chain of β-(1 → 4)-linked residues, and galactose occurs as a nonreducing terminal unit.     

Sodium Recirculation and Loss from Phaseolus vulgaris L.

In a split-root experiment, ²²Na was supplied to Phaseolus vulgarisL. roots emerging from the stem, 2.5 cm above the main roots.Sodium exported from these upper roots was translocated a shortdistance upward in the stem and downward to the main roots.Most of the ²²Na arriving in the main roots was lost to themedium. Sodium loss from P. vulgaris roots into KCI or NaCl was similarand was not affected by oligomycin. The results confirm a previous hypothesis regarding the mechanismof sodium exclusion from the tops of sodium non-accumulatorplants. Phaseolus vulgaris L., bean, sodium transport     

New isoflavonoids related to kievitone from Phaseolus vulgaris

The new isoflavonoids 5,7,2′,4′-tetrahydroxy-8-(3,3-dimethylallyl)isoflavone (2,3-dehydrokievitone) and 7,2′,4′-trihydroxy-8-(3,3-dimethylallyl)isoflavanone (5-deoxykievitone) have been isolated from fungus-inoculated Phaseolus vulgaris pod tissue and from the inoculation droplets. A third isoflavonoid was tentatively identified as 1″,2″-dehydrocyclokievitone and appears to be a metabolite of the phytoalexin kievitone.     

Purification and Partial Characterization of a Lectin from Phaseolus vulgaris

A method is presented for the isolation of a lectin from a Brazilian cultivar of the common bean (Phaseolus vulgaris L.), through extraction in acidic (pH 4.2) medium, fractionation with ammonium sulfate, and chromatography on DEAE-cellulose. The lectin was shown to be homogeneous by gel electrophoresis and isoelectric focusing.     

SH-proteinase from bean Phaseolus vulgaris var. Perlicka.

An SH-proteinase (EC 3.4.22.-) has been isolated from beans of the species Phaseolus vulgaris var. Perlicka. The enzyme is homogeneous when subjected to disc electrophoresis, electrofocusing and sedimentation analysis. The molecular weight was determined as 26,000-28,000 by gel filtration, 30,850 +/- 1500 by sedimentation analysis and 26,930-27,410 by calculation from the amino acid composition (Lys20-21, His3, Arg9, Asp21-22, Thr13, Ser18, Pro12-13, Glu23-24, Gly30, Ala16, Cys/29, Val19, Met1, Ile10, Leu13, Tyr14, Phe6, Trp3). The N-terminal amino acid of the proteinase is isoleucine. The effect of concentration, time of hydrolysis, pH, temperature, cations, anions, urea and guanidine - HCl on the proteolytic activity of the SH-proteinase was studied.     

Inhibitory specificity and insecticidal selectivity of alpha-amylase inhibitor from Phaseolus vulgaris

The primary structure and proteolytic processing of the alpha-amylase isoinhibitor alpha AI-1 from common bean (Phaseolus vulgaris cv. Magna) was determined by protein chemistry techniques. The inhibitory specificity of alphaAI-1 was screened with a panel of the digestive alpha-amylases from 30 species of insects, mites, gastropod, annelid worm, nematode and fungal phytopathogens with a focus on agricultural pests and important model species. This in vitro analysis showed a selective inhibition of alpha-amylases from three orders of insect (Coleoptera, Hymenoptera and Diptera) and an inhibition of alpha-amylases of the annelid worm. The inhibitory potential of alphaAI-1 against several alpha-amylases was found to be modulated by pH. To understand how alphaAI-1 discriminates among closely related alpha-amylases, the sequences of the alpha-amylases sensitive, respectively, insensitive to alphaAI-1 were compared, and the critical determinants were localized on the spatial alpha-amylase model. Based on the in vitro analysis of the inhibitory specificity of alphaAI-1, the in vivo activity of the ingested alphaAI-1 was demonstrated by suppression of the development of the insect larvae that expressed the sensitive digestive alpha-amylases. The first comprehensive mapping of alphaAI-1 specificity significantly broadens the spectrum of targets that can be regulated by alpha-amylase inhibitors of plant origin, and points to potential application of these protein insecticides in plant biotechnologies.     

四季豆幼苗尿囊酸酰胺水解酶的纯化和性质研究(简报)

从四季豆幼苗提取、部分纯化尿囊酸酰胺水解酶,分离出两个同功酶：一分子量同功酶（尿圳酸酰胺水解酶Ⅰ）,另一为小分子量同功酶（尿囊酸酰胺水解酶Ⅱ）,并对后者的性质进行研究。     

Ozone‐induced foliar damage and release of stress volatiles is highly dependent on stomatal openness and priming by low‐level ozone exposure in Phaseolus vulgaris

Acute ozone exposure triggers major emissions of volatile organic compounds (VOCs), but quantitatively, it is unclear how different ozone doses alter the start and the total amount of these emissions, and the induction rate of different stress volatiles. It is also unclear whether priming (i.e. pre‐exposure to lower O₃ concentrations) can modify the magnitude and kinetics of volatile emissions. We investigated photosynthetic characteristics and VOC emissions in Phaseolus vulgaris following acute ozone exposure (600 nmol mol^?1 for 30 min) under illumination and in darkness and after priming with 200 nmol mol^?1 O₃ for 30 min. Methanol and lipoxygenase (LOX) pathway product emissions were induced rapidly, followed by moderate emissions of methyl salicylate (MeSA). Stomatal conductance prior to acute exposure was lower in darkness and after low O₃ priming than in light and without priming. After low O₃ priming, no MeSA and lower LOX emissions were detected under acute exposure. Overall, maximum emission rates and the total amount of emitted LOX products and methanol were quantitatively correlated with total stomatal ozone uptake. These results indicate that different stress volatiles scale differently with ozone dose and highlight the key role of stomatal conductance in controlling ozone uptake, leaf injury and volatile release.     

Partitioning of nitrogen from biological fixation and fertilizer in Phaseolus vulgaris

Nitrogen uptake, distribution and remobilization in the vegetative and reproductive parts of the plant were studied in bean (Phaseolus vulgaris L.) cultivars Negro Argel and Rio Tibagi inoculated with either Rhizobium strain C05 or 127 K-17. Greenhouse grown plants were supplied with 2.5 mg N (plant)⁻¹ day⁻¹ as KNO₃ or K¹⁵NO₃ and the relative contribution to total plant nitrogen of mineral and symbiotically fixed nitrogen was determined. Control plants included those entirely dependent on fixed nitrogen as well as uninoculated plants supplied with 10 mg N (plant)⁻¹ day⁻¹. No differences were observed between inoculated treatments in total nitrate reductase activity and in the amount of mineral nitrogen absorbed, but there were considerable differences in the contribution of fixed nitrogen. Nitrogen fixation supplied from 58 to 72% of the total nitrogen assimilated during the bean growth cycle and the symbiotic combinations fixed most of their nitrogen (66 to 78% of total nitrogen) after flowering. Maximum uptake of mineral nitrogen was in the 15-day-period between flowering and mid-podfill (47 to 58% of total mineral nitrogen). Nitrogen partitioning varied with Rhizobium strains, and inoculation with strain C05 increased the nitrogen harvest index of both cultivars. Applied mineral nitrogen had a variable effect and in cv. Negro Argel was more beneficial to vegetative growth, resulting in smaller nitrogen harvest indices. Seed yield was not increased by heavy nitrogen fertilization. In contrast, cv. Rio Tibagi always benefited from nitrogen applications. Among the various nitrogen sources supplying the grain, the most important one was the fixed nitrogen translocated directly from nodules or after a rapid transfer through leaves, representing from 60 to 64% of the total nitrogen incorporated into the seeds.     

Purification and Characterization of a Polygalacturonase-Inhibiting Protein from Phaseolus vulgaris L

Homogeneous endo-polygalacturonase (PG) was covalently bound to cyanogen-bromide-activated Sepharose, and the resulting PG-Sepharose conjugate was utilized to purify, by affinity chromatography, a protein from Phaseolus vulgaris hypocotyls that binds to and inhibits PG. Isoelectric focusing of the purified PG-inhibiting protein (PGIP) showed a major protein band that coincided with PG-inhibiting activity. PGIP formed a complex with PG at pH 5.0 and at low salt concentrations. The complex dissociated in 0.5 m Na-acetate and pH values lower than 4.5 or higher than 6.0. Formation of the PG-PGIP complex resulted in complete inhibition of PG activity. PG activity was restored upon dissociation of the complex. The protein exhibited inhibitory activity toward PGs from Colletotrichum lindemuthianum, Fusarium moniliforme and Aspergillus niger. The possible role of PGIP in regulating the activity of fungal PG's and their ability to elicit plant defense reactions are discussed.     

Aggregation and Fragmentation of Phaseolus vulgaris Lectin

The effects of temperature on 6-O-α-maltosyl cyclodextrins (G₂-CDs) production from α- maltosylfluoride (α-G₂F) and cyclodextrins (CDs) by the transfer action of debranching enzymes such as pullulanase and isoamylase were studied.

The amounts of 6-O-α-maltosyl α-cyclodextrin (G₂-α-CD) production by purified pullulanase from Aerobacter aerogenes (A-pullulanase) and from Bacillus acidopullulyticus (B-pullulanase) increased with a rise in temperature, e.g., the amounts at 60°C were about 1.5 times higher than those at 30°C. Initial transfer ratios (G₂-α-CD formed/α-G₂F consumed) of A-pullulanase and B- pullulanase were about 62% and 25% (at 40°C), and about 50% and 15% (at 20°C), respectively. The transfer ratios of both A-pullulanase and B-pullulanase in the reaction using β-CD or γ-CD as acceptor also increased with a rise in temperature.

The transfer ratios were little affected by any change in temperature or any kind of acceptor CDs, in the case of isoamylase, and were about 60%.     

Biochemical characterization of profilin from seeds of Phaseolus vulgaris L

The isoform composition of the 14.4 kDa profilin polypeptide was analyzed in seeds, leaves, flowers, roots and root-nodules from Phaseolus vulgaris L. Isoforms of pIs approximately 4.4-5 were present in all the tissues analyzed. The biochemical features of the protein present in seed tissue were determined. Seed profilin bound to Phenyl-Sepharose under low salt conditions which suggested a hydrophobic interaction; however, it was not associated with microsomal membranes nor it partitioned as a hydrophobic protein in Triton X-114. Fractions eluting from poly-L-proline or Phenyl-Sepharose columns contained well detectable amounts of profilin but no actin, suggesting that most of the protein was not present as profilactin in the seed. However, seed profilin appeared to be in some kind of complex since several molecular weight species were observed on native gels. In addition, profilin was found preferentially in the embryo axis and light microscopic immunolocalization showed a cytoplasmic distribution in this tissue.