Purification and properties of d-galactose-binding lectins from some erythrina species: Comparison of properties of lectins from E. indica,E. arborescens,E. suberosa, and E. lithosperma

The lectins of the seeds of four species of the genus Erythrina, namely E. indica, E. arborescens, E. lithosperma, and E. suberosa were isolated by affinity chromatography on acid-treated ECD-Sepharose 6B. The lectins were found homogeneous in polyacrylamide gel electrophoresis and immunochemical tests. In SDS-gel electrophoresis, E. indica and E. lithosperma lectins each gave two bands with subunit molecular weights of 30,000 and 33,000 in the case of the former and 26,000 and 28,000 in the case of the latter. E. arborescens and E. suberosa gave single bands corresponding to polypetide chain molecular weight of 28,000. The lectins were found to be glycoproteins with their neutral sugar contents ranging from 4–9%. In carbohydrate specificity all the lectins were d-galactose specific. Their close similarity was also demonstrated by their homologous cross-reaction against the antiserum to E. indica lectin. In hemagglutinating activity toward human erythrocytes, E. indica and E. suberosa lectins showed higher activity toward the O group and E. arborescens toward the B group. The results show the similarity of the lectins derived from different species of the same genus in respect of immunochemical properties and carbohydrate specificity. In studies on E. indica lectin, the protein was found homogeneous by electrophoretic, immunochemical, and sedimentation experiments. Its molecular weight of 68,000 determined from sedimentation and diffusion data indicated that the molecule was a dimer of two noncovalently bound unequal subunits whose SDS-gel electrophoretic molecular weights are noted above. The lectin was devoid of cysteine and methionine and contained valine as its N-terminal amino acid. It had 9% neutral sugars and 1.5% glucosamine. Equilibrium dialysis studies with lactose showed that the values of the association constant K at different temperatures were of similar orders of magnitude to other lectins and the dimeric molecule possessed two noninteracting binding sites.     

An evaluation of mitochondrial heterosis and in vitro mitochondrial complementation in wheat,barley and maize

Summary Two families each of wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and maize (Zea mays L.) were studied for mitochondrial heterosis and in vitro mitochondrial complementation. Inbred parents and their hybrids were compared for seedling heights and rate of oxygen uptake by the whole tissue to find out if the hybrids showed greater growth and respiratory activity at the seedling stage. Further comparisons were made by isolating mitochondria from the seedling tissues and measuring their ADP0 ratio, respiratory control ratio and cytochrome c oxidase activity for mitochondrial heterosis. Mixtures of parental mitochondria were similarly compared with parental and hybrid mitochondria for in vitro mitochondrial complementation. No evidence for mitochondrial heterosis or in vitro mitochondrial complementation was found, nor any correlation between the different mitochondrial parameters, seedling heights or rates of oxygen uptake by seedling tissue. The suggested use of mitochondrial heterosis and in vitro mitochondrial complementation for plant breeding is discussed.Data for this paper is taken from the author's dissertation written as a part of Ph.D. degree requirements at the Biology Department, Texas A & M University, College Station, Texas     

Fatty acid composition of oil synthesized byaspergillus nidulans

The filamentous fungusAspergillus nidulans Eidam strain 300 was found to be capable of synthesizing 24.9 % oil of remarkably low free fatty acidity, in a chemically defined medium with 34 % glucose as sole carbon source. Although the total content of oil synthesized was less, utilization of the carbon source is better as shown by the high (8.4) fat coefficient. The major component fatty acids of the oil were palmitic, stearic, oleic and linoleic and are influenced by the source of carbon. Palmitoleic acid is present in traces, confirming thereby the general observation that high oil formers produce oil of low hexadecenoic acid content. The relatively high stearic acid content of the oil distinguishes it from those of other microorganisms and resembles the oil produced by certain tropical plants, such asMadhuca latifolia.     

Equilibria of the anomeric and ring forms of ammonium 3-deoxy-d-manno-octulosonate in deuterium oxide

The tautomeric composition of a solution of ammonium 3-deoxy-d-manno-octulosonate (KDO, 1a) in D₂O at 28° was assessed by means of ¹³ C-F.t.-n.m.r. spectroscopy. The results revealed the presence of 6?0 and 11 % of the α and β anomers of the pyranose, and 20 and 9 % of the two furanoses, and suggested, but did not unequivocally prove, that the major furanose form is the α anomer. To facilitate interpretation of the spectral results for 1, ammonium 3,5-dideoxy-d-arabino(or ribo)-octulosonate (3a) was prepared by the reaction of 5-deoxy-d-erythro-pentose with sodium oxalacetate at pH 11. A chromatographically homogeneous, noncrystalline sample of 3 was obtained by lyophilization, and characterized as its (4-nitrophenyl)hydrazone (m.p. 162-163°). The ¹³C-n.m.r. spectrum of a solution of 3a in D₂O revealed it to be substantially all in the α-pyranose form. No signals were obtained for the possible 1,4-lactone of 3. As the 1,5-lactone and furanose forms are impossible for 3, it exhibited no signals analogous to those attributed to furanoid 1. On the basis of these results for 3, the two lactone forms of 1 were excluded from consideration, and the three pairs of ¹³C-n.m.r. signals observed at ≈45, 86, and 104 p.p.m. were assigned to the furanose forms of 1.     

Kinetics and mechanism of oxidation of some aldoses by vanadium(v) in perchloric acid medium

The kinetics of oxidation of some aldoses by vanadium(V) in perchloric acid media have been investigated. Each reaction is first order with respect to both [Vanadium(V)] and [Aldose]. The reactions are catalysed by acid. The addition of sodium perchlorate accelerates the rate of reaction. Kinetic evidence for the formation of an intermediate compound between vanadium(V) and aldoses is insignificant, and a mechanism is suggested in which vanadium(V) reacts with the aldoses by a fast step to form a transition state, followed by the decomposition of the latter to give the products of reaction in a slow step. The formation of free-radical intermediates has been demonstrated, and one-electron reduction of vanadium(V) by aldoses seems to be the most plausible mechanism. The oxidation rates follow the order: xyloses arabinose galactose mannose. The activation parameters are reported.     

Structural investigations on the lipopolysaccharide isolated from Vibrio cholera,Inaba 569 B

On hydrolysis, the purified lipopolysaccharide (LPS) isolated from Vibrio cholera, Inaba 569 B, yielded glucose, mannose, a heptose behaving like d-glycero-l-manno-heptose and one behaving like d-glycero-l-gluco-heptose, 2-amino-2-deoxy-glucose, and glucuronic acid in the molar ratios of ～9:4:5:1:2:5. Studies on the LPS, the polysaccharide (PS), and carboxyl-reduced LPS showed that the PS has a branched structure, with (1→2)-linked mannopyranosyl and a heptopyranosyl, and (1→4)-linked glucopyranosyluronic and 2-amino-2-deoxyglucopyranosyl residues in the interior part of the molecule, and glucopyranosyl and heptopyranosyl residues as nonreducing end-groups.     

Assessment of radiosensitivity from the germination of jute seeds

Irradiation with X-rays and gamma rays reduced the speed of germination of seeds of jute cultivars,viz., JRO 632, JRO 620, Sudan Green ofCorchorus olitorius and JRC 212, Fanduk, D 154 ofC. capsularis. Though the first phase of germination(i.e. seed variability) remained apparently unaffected, the second phase (i.e. the sprouting ability) and the third phase(i.e. the attainment of autotrophic status) were found to be the best indicators of radiation injury and provided dependable data for the assessment of radiosensitivity. The jute cultivars have not shown accountable intervarietal differences in radiosensitivity in respect of LD 50 and LD 100 for the second and the third phases of germination.