PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Galanthus”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMedDate not supplied

[Comparative analysis of the monopodial and sympodial models of bulb branching in Galanthus L].

We have examined sympodial and monopodial models of bulb branching in Galanthus. The issue of the position of the reduced prophyll is discussed. We proposed a method of formal interpretation: parts of the plant were positioned on diagrams; several variants of axial schemes were matched to each diagram; the schemes were divided into two classes, monopodial and sympodial ones, and stability of each class was estimated. In order to decide about the model of Galanthus bulb branching, we have examined plants with additional inflorescences and plants with additional leaf series. We have shown that the sympodial model predicts the presence of the reduced prophyll at the base of the innovation bud in all studied cases. Consecutive stages of prophyll reduction (prophyll of the innovation bud) can be followed in Amaryllidaceae in the following sequence: Zephyranthes, a well-developed large prophyll with green lamina; Vallota, a developed prophyll with reduced green lamina; Haemanthus, a thin chaffy short-living prophyll. At the end of this sequence is Galanthus with completely reduced prophyll at the innovation bud.

Liliaceae↗
PubMed2003

Galanthamine distribution in Bulgarian Galanthus spp.

Sixteen populations of Galanthus elwesii Hook.fil and five populations of Galanthus nivalis L. growing in Bulgaria were investigated for the presence of galanthamine by TLC and GC-MS. Between 3 and 11 alkaloids were detected by TLC in the total alkaloid fractions. Galanthamine was found in 2 populations of G. elwesii.

Bulgaria↗
PubMed1996

The mannose-specific bulb lectin from Galanthus nivalis (snowdrop) binds mono- and dimannosides at distinct sites. Structure analysis of refined complexes at 2.3 A and 3.0 A resolution.

Galanthus nivalis agglutinin (GNA, a 50 kDa tetramer) is a mannose-specific lectin of the Amaryllidaceae family of bulb lectins. Crystal structures of GNA complexed with methyl-alpha-D-mannose (MeMan) and mannose-alpha 1,3-D-mannose-alpha-OMe (MeMan-2) have been determined and analyzed in terms of internal structural symmetry and saccharide binding. The final model of the 2.29 A orthorhombic methyl-alpha-Man complex refined with an R-factor of 0.167 (all data) includes 12 bound sugar ligands and 327 water molecules. The four independent subunits (A, B, C and D) of the 222 tetramer and the three four-stranded beta-sheets (I,II and III) that constitute each subunit compare closely (r.m.s. delta = < 1.0 A). The 12 bound methyl-alpha-Man molecules refined with B-factors < 22 A2 and occupancies in the range of 0.5 to 1.0. The highest occupied site is located in beta-sheet I (site 1), where interactions from the dimer-related subunit contribute to complex stabilization. These subunit pairs (A-D and B-C) associate tightly with a buried surface area of 1738 A2 and 33 interchain hydrogen bonds resulting from C-terminal strand exchange. In comparison, the A-B and C-D subunit pairs have narrow interfaces (476 A2) and no direct H-bond contacts. The 3.0 A structure of the cubic Man-alpha 1,3-Man-OMe complex, determined by molecular replacement and refined with X-PLOR using NCS constraints and density modification methods, is less well ordered due to a high crystal solvent content (68%). Complexed disaccharide is responsible for the most crucial lattice contacts, which involve only one of the two independent subunits (A). The second subunit (C) shows a high degree of flexibility (Bav = 41.7 A2). The complete disaccharide molecule is visible in both subunits at site 3, which is the only extended site. The ligand is oriented with its reducing end positioned in the specificity pocket. The non-reducing manose is in contact through hydrogen bonding with a charged subsite (D37-K38) on the 2-fold-related subunit (A-B or C-D interfaces). Bound Man-alpha 1,3-MeMan is also well defined in site 2 of subunit A, as a result of favorable lattice contacts, while only the mannose residue bound in the specificity pocket is visible at site 2 of subunit C and site 1 of both subunits. Together these results suggest that strong binding correlates with the presence of subsidiary contacts coming either from a dimer-related subunit or from lattice interactions. Site 1 is most specific for terminal non-reducing or reducing mannose, while site 3 is extended and complementary to alpha-1,3 linked mannose oligosaccharides.

Amino Acid Sequence↗
PubMed2006

A 90-day safety study in Wistar rats fed genetically modified rice expressing snowdrop lectin Galanthus nivalis (GNA).

Genetically modified plants expressing insecticidal traits offer a new strategy for crop protection, but at the same time present a challenge in terms of food safety assessment. The present 90-day feeding study was designed to assess the safety of a rice variety expressing the snowdrop Galanthus nivalis lectin (GNA lectin), and forms part of a EU-funded project where the objective has been to develop and validate sensitive and specific methods to assess the safety of genetically modified foods. Male and female Wistar rats were given a purified diet containing either 60% genetically modified or parental rice for 90 days. This corresponds to a mean daily GNA lectin intake of approximately 58 and 67mg/kg body weight for males and females, respectively. Prior to the animal study comprehensive analytical characterization of both rice materials was performed. The chemical analyses showed a number of statistically significant differences, with the majority being within the ranges reported in the literature. In the animal study a range of clinical, biological, immunological, microbiological and pathological parameters were examined. A number of significant differences were seen between groups fed the two diets, but none of them were considered to be adverse. In conclusion, the design of the present animal study did not enable us to conclude on the safety of the GM food. Additional group(s) where the expressed gene products have been spiked to the diet should be included in order to be able to distinguish whether the observed effects were due to the GNA lectin per se or to secondary changes in the GM rice.

Animals↗
PubMed2005

Quantitative and cytotoxic activity determinations on Galanthus nivalis subsp. cilicicus.

Aerial and underground parts of Galanthus nivalis subsp. cilicicus, a wild-growing species in Turkey, were collected during two different vegetation periods in flowering and fruiting seasons. Herba and bulbus Galanthi were prepared from each specimen. With the aim of collecting data for prospective monographs on this drug, contents of humidity, ash, sulphated ash and total alkaloids were determined according to DAB 10. The specimens were also analyzed quantitatively for two of the principal alkaloids of the genus, galanthamine and lycorine, by using a method based on spectrophotometry complemented with TLC. LC50 values were determined for the ethanolic and alkaloidal extracts of each of the specimens using brine shrimp lethality bioassay.

Alkaloids↗
PubMed2004

Intraspecific variability in the alkaloid metabolism of Galanthus elwesii.

Alkaloid pattern of individuals from 16 Bulgarian Galanthus elwesii populations was investigated by GC/MS and TLC. Twenty-one Amaryllidaceae alkaloids were detected and 14 of them were identified. Crinane type alkaloids, haemanthamine or crinine, dominated alkaloid metabolism in most of the populations. With exception of one population, where the separate individuals showed variable alkaloid profiles (dominated by crinine or haemanthamine) the individuals of the rest of populations have identical and characteristic alkaloid profiles. Some populations showed remarkable differences in respect to their alkaloid pattern-type of biosynthesis, main alkaloids and number of alkaloids. Populations dominated by galanthamine type alkaloids were found as well. These data demonstrate that like the morphological features, the alkaloid metabolism of G. elwesii is also variable.

Alkaloids↗
PubMed1999

Effect of diets containing genetically modified potatoes expressing Galanthus nivalis lectin on rat small intestine.

Diets containing genetically modified (GM) potatoes expressing the lectin Galanthus nivalis agglutinin (GNA) had variable effects on different parts of the rat gastrointestinal tract. Some effects, such as the proliferation of the gastric mucosa, were mainly due to the expression of the GNA transgene. However, other parts of the construct or the genetic transformation (or both) could also have contributed to the overall biological effects of the GNA-GM potatoes, particularly on the small intestine and caecum.

Animals↗
PubMed2003

Large-scale production and purification of recombinant Galanthus nivalis agglutinin (GNA) expressed in the methylotrophic yeast Pichia pastoris.

The gene coding for agglutinin from Galanthus nivalis (GNA) was expressed in, and secreted by, the methylotrophic yeast, Pichia pastoris. Transformants of P. pastoris were selected and a process to produce and purify gram quantities of recombinant GNA was developed. GNA was secreted at approximately 80 mg l(-1) at the 200 1 scale and was purified to 95% homogeneity using hydrophobic interaction chromatography. The recombinant protein was similar to the protein synthesised in plant with respect to structure and biological activity.

Amino Acid Sequence↗
PubMed1995

Structure of mannose-specific snowdrop (Galanthus nivalis) lectin is representative of a new plant lectin family.

Tetrameric Galanthus nivalis agglutinin (50,000 M(r)) belongs to a super-family of alpha-D-mannose-specific plant bulb lectins known to be potent inhibitors of retroviruses. The 2.3 A crystal structure of this lectin complexed with methyl alpha-D-mannose reveals a novel three-fold symmetric beta-sheet polypeptide fold. Three antiparallel four-stranded beta-sheets, each with a conserved mannose-binding site, are arranged as a 12-stranded beta-barrel. The tetramer displays 222 symmetry. Pairs of monomers form stable dimers through C-terminal strand exchange. The so formed hybrid beta-sheets are the sites for high affinity mannose binding in the dimer interface. Occupancy observed at corresponding sites in other beta-sheets suggests a potential for twelve sites per tetramer.

Amino Acid Sequence↗
PubMed2000

Modulation of Salmonella infection by the lectins of Canavalia ensiformis (Con A) and Galanthus nivalis (GNA) in a rat model in vivo.

The plant lectins, Concanavalin A (Con A) and Galanthus nivalis agglutinin (GNA) have been prefed to rats for 3 d pre- and 6 d postinfection with Salmonella typhimurium S986 or Salm. enteritidis 857. Con A significantly increased numbers of Salm. typhimurium S986 in the large intestine and in faeces, and severely impaired growth of the rats, more severely than is the case of infection with Salmonella typhimurium alone. Con A had much less effect on rats infected with Salm. enteritidis 857 only showing a significant increase in numbers in the colon, accompanied by intermittent increases of Salmonella in the faeces during the study. GNA significantly reduced pathogen numbers in the lower part of the small bowel and the large intestine of rats infected with Salm. typhimurium S986 and significantly improved rat growth. GNA had little effect on infection by Salm. enteritidis 857 with slight decreases in Salmonella numbers in the small intestine and large intestine and transient increases in the faeces.

Animals↗
PubMed1999

Functional phytohemagglutinin (PHA) and Galanthus nivalis agglutinin (GNA) expressed in Pichia pastoris correct N-terminal processing and secretion of heterologous proteins expressed using the PHA-E signal peptide.

Phytohemagglutinin (Phaseolus vulgaris agglutinin; PHA; E- and L-forms) and snowdrop lectin (Galanthus nivalis agglutinin; GNA) were expressed in Pichia pastoris using native signal peptides, or the Saccharomyces alpha-factor preprosequence, to direct proteins into the secretory pathway. PHA and GNA were present as soluble, functional proteins in culture supernatants when expressed from constructs containing the alpha-factor preprosequence. The recombinant lectins, purified by affinity chromatography, agglutinated rabbit erythrocytes at concentrations similar to the respective native lectins. However, incomplete processing of the signal sequence resulted in PHA-E, PHA-L and GNA with heterogenous N-termini, with the majority of the protein containing N-terminal extensions derived from the alpha-factor prosequence. Polypeptides in which most of the alpha-factor prosequence was present were also glycosylated. Inclusion of Glu-Ala repeats at the C-terminal end of the alpha-factor preprosequence led to efficient processing N-terminal to the Glu-Ala sequence, but inefficient removal of the repeats themselves, resulting in polypeptides with heterogenous N-termini still containing N-terminal extensions. In contrast, PHA expressed with the native signal peptide was secreted, correctly processed, and also fully functional. No expression of GNA from a construct containing the native GNA signal peptide was observed. The PHA-E signal peptide directed correct processing and secretion of both GNA and green fluorescent protein (GFP) when used in expression constructs, and is suggested to have general utility for synthesis of correctly processed proteins in Pichia.

Amino Acid Sequence↗
PubMed2003

Galanthindole: a new indole alkaloid from Galanthus plicatus ssp. byzantinus.

A new indole alkaloid, galanthindole, was isolated from Galanthus plicatus ssp. byzantinus (Amaryllidaceae), a plant native to northwestern Turkey. Incorporating a non-fused indole ring, galanthindole may represent the prototype of a new subgroup of the Amaryllidaceae alkaloids. Two other bases, (+)-11-hydroxyvittatine and hordenine, are also reported from the same plant.

Alkaloids↗
PubMed1993

Envelope glycoproteins of HIV-1, HIV-2, and SIV purified with Galanthus nivalis agglutinin induce strong immune responses.

Lectin affinity chromatography was used to purify in a single step the envelope glycoproteins of HIV-1, HIV-2, and SIV. Envelope glycoproteins carry the major determinants essential for protection by the humoral immune response. The purification of these proteins has previously been a laborious procedure. The glycoproteins were purified by a one-step procedure to a high level of purity by using Galanthus nivalis agglutinin (GNA). The purified glycoprotein had CD4-binding and antigenic reactivities. Strong immune responses to envelope proteins and peptides were seen in mice and primates after immunization with these preparations.

Animals↗
PubMed1983

Homer's moly identified as Galanthus nivalis L.: physiologic antidote to stramonium poisoning.

The antidotal properties of certain naturally occurring medicinal plants against central nervous system intoxication appear to have been empirically established in ancient times. Homer, in his epic poem, the Odyssey, described a plant, "moly," used by Odysseus as an antidote against Circe's poisonous drugs. Centrally acting anticholinergic agents are thought to have been used by Circe to induce amnesia and a delusional state in Odysseus' crew. We present evidence to support the hypothesis that "moly" might have been the snowdrop, Galanthus nivalis, which contains galanthamine, a centrally acting anticholinesterase. Thus the description of "moly" as an antidote in Homer's Odyssey may represent the oldest recorded use of an anticholinesterase to reverse central anticholinergic intoxication.

Antidotes↗
PubMed1991

Biosynthesis, primary structure and molecular cloning of snowdrop (Galanthus nivalis L.) lectin.

Poly(A)-rich RNA isolated from ripening ovaries of snowdrop (Galanthus nivalis L.) yielded a single 17-kDa lectin polypeptide upon translation in a wheat-germ cell-free system. This lectin was purified by affinity chromatography. Translation of the same RNA in Xenopus leavis oocytes revealed a lectin polypeptide which was about 2 kDa smaller than the in vitro synthesized precursor, suggesting that the oocyte system had removed a 2-kDa signal peptide. A second post-translational processing step was likely to be involved since both the in vivo precursor and the Xenopus translation products were about 2 kDa larger than the mature lectin polypeptide. This hypothesis was confirmed by the structural analysis of the amino acid sequence of the mature protein and the cloned mRNA. Edman degradation and carboxypeptidase Y digestion of the mature protein, and structural analysis of the peptides obtained after chemical cleavage and modification, allowed determination of the complete 105 amino acid sequence of the snowdrop lectin polypeptide. Comparison of this sequence with the deduced amino acid sequence of a lectin cDNA clone revealed that besides the mature lectin polypeptide, the lectin mRNA also encoded a 23 amino acid signal-sequence and a C-terminal extension of 29 amino acids, which confirms the results from in vitro translation experiments.

Amino Acid Sequence↗
PubMed2005

Marked depletion of glycosylation sites in HIV-1 gp120 under selection pressure by the mannose-specific plant lectins of Hippeastrum hybrid and Galanthus nivalis.

The plant lectins from Hippeastrum hybrid (HHA) and Galanthus nivalis (GNA) are 50,000-D tetramers showing specificity for alpha-(1,3) and/or alpha-(1,6)-mannose oligomers. They inhibit HIV-1 infection at a 50% effective concentration of 0.2 to 0.3 microg/ml. Escalating HHA or GNA concentrations (up to 500 microg/ml) led to the isolation of three HIV-1(III(B)) strains in CEM T cell cultures that were highly resistant to HHA and GNA, several other related mannose-specific plant lectins, and the monoclonal antibody 2G12, modestly resistant to the mannose-specific cyanovirin, which is derived from a blue-green alga, but fully susceptible to other HIV entry inhibitors as well as HIV reverse transcriptase inhibitors. These mutant virus strains were devoid of up to seven or eight of 22 glycosylation sites in the viral envelope glycoprotein gp120 because of mutations at the Asn or Thr/Ser sites of the N-glycosylation motifs. In one of the strains, a novel glycosylation site was created near a deleted glycosylation site. The affected glycosylation sites were predominantly clustered in regions of gp120 that are not involved in the direct interaction with either CD4, CCR5, CXCR4, or gp41. The mutant viruses containing the deleted glycosylation sites were markedly more infectious in CEM T-cell cultures than wild-type virus.

Anti-HIV Agents↗
PubMed1990

Crystallization and preliminary X-ray diffraction results of snowdrop (Galanthus nivalis) lectin.

Well-ordered single crystals have been grown for a mannose-specific lectin from snowdrop (Galanthus nivalis) bulbs in the presence of methyl-alpha-D-mannoside. The space group symmetry is consistent with the orthorhombic space group P2(1)2(1)2(1). The unit cell parameters are a = 140.0 A, b = 64.7 A, c = 62.0 A. The asymmetric unit can accommodate a tetramer. The functional molecule (50,000 daltons) consists of four identical subunits and is highly specific for alpha 1,3-linked mannose oligosaccharides.

Crystallography↗