Scilla Campanulata Research Articles

Purification and Crystallisation of a Novel Two-Domain Lectin from Scilla Campanulata

Abstract: In the last decade a number of single-domain mannose-binding lectins (11-14 kDa) have l:ieen characterised from different monocot plants and shown to belong to a superfamily of evolutionary related proteins. We have isolated and crystallized a novel two-domain, multivalent lectin, with 26.2 kDa subunits, from Scilla campanulata bulbs. The native agglutinin crystallizes in space group C2 and 3.3A resolution data set has been recorded.

Structural characterisation of the native fetuin-binding protein Scilla campanulata agglutinin: a novel two-domain lectin

The three-dimensional structure of a 244-residue, multivalent, fetuin-binding lectin, SCAfet, isolated from bluebell ( Scilla campanulata) bulbs, has been solved at 3.3 Å resolution by molecular replacement using the coordinates of the 119-residue, mannose-binding lectin, SCAman, also from bluebell bulbs. Unlike most monocot mannose-binding lectins, such as Galanthus nivalis agglutinin from snowdrop bulbs, which fold into a single domain, SCAfet contains two domains with approximately 55% sequence identity, joined by a linker peptide. Both domains are made up of a 12-stranded β-prism II fold, with three putative carbohydrate-binding sites, one on each subdomain. SCAfet binds to the complex saccharides of various animal glycoproteins but not to simple sugars.

ChemInform Abstract: Polyhydroxylated Pyrrolidine and Pyrrolizidine Alkaloids from Hyacinthoides non‐scripta and Scilla campanulata.

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Structure of the native (unligated) mannose-specific bulb lectin from Scilla campanulata (bluebell) at 1.7 A resolution.

The X-ray crystal structure of native Scilla campanulata agglutinin, a mannose-specific lectin from bluebell bulbs and a member of the Liliaceae family, has been determined by molecular replacement and refined to an R value of 0.186 at 1.7 A resolution. The lectin crystallizes in space group P21212 with unit-cell parameters a = 70. 42, b = 92.95, c = 46.64 A. The unit cell contains eight protein molecules of Mr = 13143 Da (119 amino-acid residues). The asymmetric unit comprises two chemically identical molecules, A and B, related by a non-crystallographic twofold axis perpendicular to c. This dimer further associates by crystallographic twofold symmetry to form a tetramer. The fold of the polypeptide backbone closely resembles that found in the lectins from Galanthus nivalis (snowdrop) and Hippeastrum (amaryllis) and contains a threefold symmetric beta-prism made up of three antiparallel four-stranded beta-sheets. Each of the four-stranded beta-sheets (I, II and III) possesses a potential saccharide-binding site containing conserved residues; however, site II has two mutations relative to sites I and III which may prevent ligation at this site. Our study provides the first accurate and detailed description of a native (unligated) structure from this superfamily of mannose-specific bulb lectins and will allow comparisons with a number of lectin-saccharide complexes which have already been determined or are currently under investigation.

Isolation, characterization, molecular cloning and molecular modelling of two lectins of different specificities from bluebell (Scilla campanulata) bulbs

Two lectins have been isolated from bluebell (Scilla campanulata) bulbs. From their isolation by affinity chromatography, they are characterized as a mannose-binding lectin (SCAman) and a fetuin-binding lectin (SCAfet). SCAman preferentially binds oligosaccharides with α(1,3)- and α(1,6)-linked mannopyranosides. It is a tetramer of four identical protomers of approx. 13 kDa containing 119 amino acid residues; it is not glycosylated. The fetuin-binding lectin (SCAfet), which is not inhibited by any simple sugars, is also unglycosylated. It is a tetramer of four identical subunits of approx. 28 kDa containing 244 residues. Each 28 kDa subunit is composed of two 14 kDa domains. Both lectins have been cloned from a cDNA library and sequenced. X-ray crystallographic analysis and molecular modelling studies have demonstrated close relationships in sequence and structure between these lectins and other monocot mannose-binding lectins. A refined model of the molecular evolution of the monocot mannose-binding lectins is proposed.

Isolation, characterization, molecular cloning and molecular modelling of two lectins of different specificities from bluebell (Scilla campanulata) bulbs

Two lectins have been isolated from bluebell (Scilla campanulata) bulbs. From their isolation by affinity chromatography, they are characterized as a mannose-binding lectin (SCAman) and a fetuin-binding lectin (SCAfet). SCAman preferentially binds oligosaccharides with alpha(1,3)- and alpha(1,6)-linked mannopyranosides. It is a tetramer of four identical protomers of approx. 13 kDa containing 119 amino acid residues; it is not glycosylated. The fetuin-binding lectin (SCAfet), which is not inhibited by any simple sugars, is also unglycosylated. It is a tetramer of four identical subunits of approx. 28 kDa containing 244 residues. Each 28 kDa subunit is composed of two 14 kDa domains. Both lectins have been cloned from a cDNA library and sequenced. X-ray crystallographic analysis and molecular modelling studies have demonstrated close relationships in sequence and structure between these lectins and other monocot mannose-binding lectins. A refined model of the molecular evolution of the monocot mannose-binding lectins is proposed.

Polyhydroxylated pyrrolidine and pyrrolizidine alkaloids from Hyacinthoides non- scripta and Scilla campanulata

Aqueous ethanol extracts from the immature fruits and stalks of bluebell ( Hyacinthoides non- scripta) were subjected to various ion-exchange column chromatographic steps to give 1,4-dideoxy-1,4-imino- d-arabinitol ( 1), 2( R),5( R)-bis(hydroxymethyl)-3( R),4( R)-dihydroxypyrrolidine (DMDP) ( 2), 6-deoxy-6- C-(2,5-dihydroxyhexyl)-DMDP ( 3), 2,5-dideoxy-2,5-imino- dl- glycero- d- manno-heptitol (homoDMDP) ( 4), homoDMDP-7- O-apioside ( 5), homoDMDP-7- O-β- d-xylopyranoside ( 6), (1 S*,2 R*,3 R*,5 R*,7a R*)-1,2-dihydroxy-3,5-dihydroxymethylpyrrolizidine ( 7), and (1 S*,2 R*,3 R*,5 R*,6 R*,7 R*,7a R*)-3-hydroxymethyl-5-methyl-1,2,6,7-tetrahydroxypyrrolizidine ( 8). Bulbs of Scilla campanulata (Hyacinthaceae) yielded (1 S*,2 R*,3 R*,5 S*,7a R*)-1,2-dihydroxy-3,5-dihydroxymethylpyrrolizidine ( 9) in addition to compounds 1– 7. Compounds 3, 6, 7, 8, and 9 are new natural products. Compound 4 is a potent competitive inhibitor with K i values of 1.5 μM for Caldocellum saccharolyticum β-glucosidase and 2.2 μM for bovine liver β-galactosidase. The 7- O-β- d-xyloside 6 was a stronger competitive inhibitor than 4 of C. saccharolyticum β-glucosidase and rat intestinal lactase, with K i values of 0.06 and 0.07 μM, respectively, but a weaker inhibitor of bovine liver β-galactosidase. Furthermore, compound 4 is also a competitive inhibitor ( K i=1.8 μM) of porcine kidney trehalase, but 6 was inactive against this enzyme.

Crystallization and preliminary crystallographic analysis of scilla campanulata lectin complexed with A-D-mannose

Abstract: Recently many new lectins have been isolated from monocotyledonous plants which have interesting glycan­ binding behaviour. In this paper we present the crystallization and preliminary X-ray analysis of a lectin, isolated from bluebell (Scilla campanulata) bulbs, complexed with a-D-mannose. The complex crystallizes in space group P21212 with a= 70.73, b = 92.97 and c = 47.07A. Synchrotron X-ray data have been measured at 1.86A resolution and the crystal structure of the complex will be solved by the molecular replacement method.

Purification, crystallization and preliminary X-ray analysis of a mannose-binding lectin from bluebell (Scilla campanulata) bulbs.

Crystals have been grown of a mannose-specific lectin from bluebell (Scilla campanulata) bulbs in a form suitable for X-ray diffraction studies. The crystals, which diffract to high resolution, grew in hanging drops by vapour diffusion, equilibrating with a solution of 70% saturated ammonium sulfate at pH 4.7-4.8 at 293 K, in the absence of any mannose saccharides. Crystals are orthorhombic, P2(1)2(1)2, with unit-cell dimensions a = 70.78, b = 93.69, c = 46.92 A. The functional lectin molecule is organized as a tetramer of four identical 14 kDa subunits, with only two subunits in the asymmetric unit. Data to 1.86 A resolution have been recorded and the structure determined by the molecular replacement method.

The Effect of Germicides on the Longevity of Cut Flowers

The effect of DICA (50 mg·liter-1), BCDMH (12 mg available chlorine/liter), and HQC (250 mg-liter]) on the longevity of 14 popular cut flower species was assessed. Longevity was significantly extended in: Rosa hybrida L. `Gabrielle' and Scilla campanulata L. Squill. by all germicides; Lilium parkmannii L. `Nepal', Gerbera jamesonii L. `Mercy', and Narcissus tazetta L. `Fortune' by DICA and BCDMH; Gypsophila paniculata L. `R22' by DICA and HQC; and Freesia hybrida Eckl. ex Klatt `White Bergunden' by BCDMH. No effect on longevity was found in Dendranthema grandiflora (Ramat) Kitamura. `Horim', Dianthus caryophyllus L. `Medea', Dianthus barbatus L., Iris hollandica L. `Pearl', and Gerbera jamesonii L. `Double Delight'. Longevity was significantly reduced by DICA in Alstroemeria aurantiaca L. `Mona Lisa' and Tulipa hybrida L. `Apeldoorn'. Analysis of microbial concentrations showed that proliferation was effectively controlled by DICA and BCDMH, but not by HQC. Levels of up to 106 cfu·ml-1 were detected in water, indicating that species not affected by germicides can tolerate these microbial quantities. Fresh weight and solution uptake data indicated that germicides acted primarily by improving solution uptake. Longevity was significantly reduced in R. hybrida `Gabrielle' and D. caryophyllus `Medea' flowers placed in solutions containing high counts of microorganisms (>108 cfu·ml-1) isolated from D. caryophyllus or R. hybrida. Chemical names used: 1-bromo-3-chloro-5,5-dimethylhydantoin (BCDMH); sodium dichloroisocyanuric acid (DICA); 8-hydroxyquinoline citrate (HQC).

Multiplicity of ribosomal RNA genes in five species of the Liliaceae

Abstract The percentages of DNA complementary to ribosomal RNA in five species of the Liliaceae family was determined by rRNA/DNA hybridization experiments. The rDNA percentages are appreciably lower in Scilla campanulata (0.050%), Scilla sibirica (0.060%) and Bellevalia webbiana (0.076%), species with higher DNA per 2C nucleus content, than in Allium schoenoprasum (0.106%) and Leopoldia comosa (0.148%), species with lower DNA per 2C nucleus content. A comparison is made with other results on the same subject.

A correlation between the localisation of chiasmata and the replication pattern of chromosomal DNA

The distribution of chiasmata at meiosis within chromosomes of Scilla campanulata is correlated with the pattern of DNA replication of late S. Chromosome regions with the highest degree of DNA synthesis at late S, namely those interstitial segments away from the chromosome ends and from the centromeres, have the highest chiasma frequencies. A causal relation is suggested.

The pattern of DNA replication at mitosis in the chromosomes of Scilla campanulata

In autoradiographs, following tritium labelling at late S, analyses of the distributions of silver grains along the chromosomes of Scilla campanulata led to the following conclusions. 1. 1. The variation in amount of DNA replication between chromosomes at late S is directly proportional to chromosome length. 2. 2. Within chromosomes the amount of DNA replication per unit of length varies between different regions. It is lowest near to the ends and in the vicinity of the centromere, highest in interstitial regions away from the centromere. It follows that DNA replication is completed earlier near to the centromeres and at the ends than elsewhere. 3. 3. The “end” and “centromere” effects upon DNA replication at late S are of the same order of magnitude.