Evaluación biométrica de taxa arbustivos de Datura L. prospectados en diferentes regiones del país. / Biometric assessment of taxa arbustivos of Datura L. prospected in different regions of the country

Fueron prospectados en diferentes regiones del país 22 taxa de especie arbustivas del género Datura L. (Solanaceae), los que posteriormente se plantaron por estacas según un diseño de bloques al azar con 3 repeticiones, en terrenos de la Estación Experimental de Plantas Medicinales "Dr. Juan Tomás Roig" en San Antonio de los Baños, La Habana. Durante 3 cosechas del material vegetal fueron evaluados 15 plantas de cada taxon; en cada una se consideró: altura, número de hojas, número de ramificaciones, largo y ancho de la hoja, longitud del peciolo, rendimiento de material vegetal y rendimiento de escopolamina. Los datos fueron evaluados mediante un análisis de varianza de clasificación doble. Datura cubensis Fuentes, Datura sp. (procedente de Gran Piedra), y otros 5 taxa prospectados en la localidad de Monteverde, provincia Guantánamo, alcanzaron en general los mayores valores en rendimiento de material vegetal y en estimados de escopolamina por hectáreas, superando a Datura candida (Pers.) Safford, especie recomendada actualmente para su explotación comercial. Los taxa de prospectados constituyen un excelente material para futuros trabajos de mejoramiento

Isolation and structure of a pseudopeptide gamma-L-glutamyl-L-aspartic acid from Datura stramonium that impairs learning retention in mice.

Datura stramonium contains a compound that impairs learning retention in mice. It has been purified to homogeneity and its structure has been established as that of a gamma-L-glutamyl-L-aspartate. The biological activity of this pseudodipeptide has been found to be identical with that of the corresponding synthetic one. It has also been compared to those of various synthetic di- and tripeptides containing L- and/or D-enantiomers of the constitutive amino acids. The results show that the activity is associated with a peptidic structure containing only one type of enantiomer.

Lectin affinity high-performance liquid chromatography: interactions of N-glycanase-released oligosaccharides with leukoagglutinating phytohemagglutinin, concanavalin A, Datura stramonium agglutinin, and Vicia villosa agglutinin.

We have developed a lectin affinity high-performance liquid chromatography technique for analysis of oligosaccharides using columns of silica-bound lectins. Purified leukoagglutinating phytohemagglutinin (L-PHA), concanavalin A (Con A), Datura stramonium agglutinin (DSA), and Vicia villosa agglutinin (VVA) were covalently coupled to periodate-oxidized diol-silica by reductive amination. Homogeneous oligosaccharides of known structure, purified following release from Asn with N-glycanase and reduction with NaBH4, were tested for their ability to interact with the silica-bound lectins. The characteristic elution position obtained for each oligosaccharide was reproducible and correlated with specific structural features. The oligosaccharide specificities displayed by silica-bound L-PHA, Con A, and DSA were virtually identical to those established utilizing lectin-agarose conjugates. Analysis of oligosaccharides by lectin affinity HPLC allowed further definition of the specificity of VVA for N-glycanase-released, reduced oligosaccharides. Lectin affinity HPLC is rapid and convenient, providing an important structure-specific dimension to oligosaccharide analysis. This technique is particularly useful when utilized in conjunction with anion-exchange and ion-suppression amine adsorption HPLC methods, which fractionate on the basis of charge and size, respectively. In addition to their utility for oligosaccharide characterization, these affinity columns demonstrate the high degree of oligosaccharide specificity displayed by plant and animal lectins.

Desarrollo de la enfermedad producida por Alternaria crassa (Sacc.) Rands en Datura candida (Pers.) Safford (II) en plantas de diferentes edades y hojas inferiores y superiores / Development of disease produced by Alternaria crassa (Sacc.) Rands in Datura candida (Pers.) Safford (II) in plants of different ages and lower and upper leaves

Se estudió el desarrollo de la enfermedad ocasionada por el hongo Alternaria crassa (Sacc.) Rands en planta de Datura candida (Pers.) Safford de diferentes edades: 4, 12, 24, y 43 meses, entre junio y septiembre de 1979, utilizándonse para la evaluación la metodología propuesta posteriormente por Fornet (1983) y el número de manchas en hojas inferiores y superiores de plantas de 6 y 24 meses en agosto del mismo año. Los experimentos se realizaron en la Estación Experimental de Plantas Medicinales "Dr. Juan Tomás Roig" de San Antonio de los Baños, provincia de la Habana. Se encontraron valores altamente significativos entre los meses y entre las edades, así como interrelación entre ambos factores, mientras que el numero de manchas fue significativamente mayor en las hojas inferiores

Determination of nucleotide pools in plant tissue by high-performance liquid chromatography.

A procedure for the determination of nucleotide pools in plant tissue by HPLC is described. Sample preparation includes the extraction with 0.4 M HClO4, a purification step, which proved to be essential, on a disposable prepacked phenyl-bonded column, neutralization by KOH, and concentration by freeze-drying. The determination of a broad spectrum of ribonucleotides including the ribonucleosides was performed by combining anion-exchange and reversed-phase HPLC. Data are presented for suspension-cultured cells of Nicotiana tabacum and Datura innoxia and for the leaf and root of tobacco.

Role played by narcotics laboratories in the campaign against drug abuse and drug trafficking: a view from a developing country.

The narcotics laboratory at the national level identifies drugs for abuse and their accompanying substances in suspected samples, determines the purity and the possible origin of illicit drugs, carries out drug-related research, particularly on new sources of drugs liable to abuse, and, when required by the police or courts of law, provides supportive expertise in drug trafficking cases. Precaution must be taken to ensure that samples to be examined are representative. The university is a particularly appropriate setting for the location of a narcotics laboratory, especially if such a laboratory carries out complex work requiring assistance from other professional disciplines. Before new laboratory equipment is purchased, a careful study of requirements and financial resources should be made to ensure economical and optimum utilization of such equipment. In some situations the use of simple techniques, such as thin-layer chromatography, can be sufficient, while in others more sophisticated techniques may be required. Appropriate training of personnel is of particular importance for the effective functioning of a narcotics laboratory. The laboratory of the Department of Toxicology and Forensic Chemistry, University of Buenos Aires, provides for the training of personnel at three levels: The first level consists of basic training, which includes the use of kits for rapid identification of drugs in field conditions, for personnel from the police, gendarmerie, prefecture, customs and other agencies which deal with drug problems, but which have no previous skills in laboratory techniques; The second level is provided for professional laboratory personnel and usually lasts six months; The third level consists of two years' postgraduate university training for students who are expected to carry out complex laboratory work; an additional year is provided for trainees who are expected to assume responsibility in a laboratory unit.

Structural studies of the carbohydrate moieties of lectins from potato (Solanum tuberosum) tubers and thorn-apple (Datura stramonium) seeds.

1. Methylation analysis of potato (Solanum tuberosum) lectin and thorn-apple (Datura stramonium) lectin confirmed previous conclusions that both glycoproteins contained high proportions of l-arabinofuranosides and lesser amounts of d-galactopyranosides. The arabinofuranosides are present in both lectins as short unbranched chains containing 1-->2- and 1-->3-linkages, which are known to be linked to hydroxyproline. Galactopyranosides are present as monosaccharides, which are known to be attached to serine, in potato lectin and as both the monosaccharide and the 1-->3-linked disaccharide in Datura lectin. 2. Alkaline digestion of potato lectin and subsequent separation of the components by gel filtration led to the isolation of four fractions corresponding to the mono-, di-, tri- and tetra-arabinosides of hydroxyproline. The latter two fractions accounted for over 70% of the total hydroxyproline. 3. Methylation analysis was used to show that the triarabinoside contained only 1-->2-linkages between sugars, but that the tetra-arabinoside contained both 1-->2- and 1-->3-linkages. Direct-insertion mass spectrometry of these compounds using electron impact and chemical ionization, in a comparison with other known structural patterns, was used to determine the sequences of the sugars, which were Araf1-->2Araf1-->2Araf1-->Hyp and Araf1-->3Araf1-->2Araf1-->2Araf 1-->Hyp. 4. On the basis of optical rotation it had previously been suggested [Allen, Desai, Neuberger & Creeth (1978) Biochem. J.171, 665-674] that all the arabinose of potato lectin was present as the beta-l-furanoside. However, measurement of the optical rotations of the hydroxyprolyl arabinosides showed that whereas the diarabinoside had a molar rotation ([m]) value close to that predicted, the triarabinoside was more dextrorotatory and the tetra-arabinoside was less dextrorotatory than expected. Possible explanations for these findings are that, although the di- and tri-arabinosides contain exclusively beta-arabinofuranosides, in the tri-arabinoside, interactions between pentose units lead to an enhanced positive rotation. The tetra-arabinoside, however, is proposed to contain a single alpha-arabinofuranoside residue, which is responsible for the lower than expected positive rotation. The observed rotation of the tetra-arabinoside was found to be close to the theoretical value predicted on that basis. Furthermore, the action of a specific alpha-arabinofuranosidase on the tetrasaccharide was to remove a single arabinose residue, presumably the terminal non-reducing sugar, and to produce a product that was indistinguishable on electrophoresis from the triarabinoside. Changes in rotation were compatible with this assumption. 5. It is concluded that the structures of the hydroxyprolyl tri- and tetra-arabinosides of potato lectin are: betaAraf1-->2betaAraf1-->2betaAraf1-->Hyp and alphaAraf1-->3betaAraf1-->2betaAraf 1-->2betaAraf1-->Hyp. These are identical with compounds that have been isolated from the insoluble hydroxyproline-rich glycoproteins of plant cell walls.

Some properties of the lectin from Datura stramonium (thorn-apple) and the nature of its glycoprotein linkages.

The lectin from Datura stramonium (thorn-apple; Solanaceae) has been purified by affinity chromatography and shown to be a glycoprotein containing about 40% (w/w) of carbohydrate. The most abundant amino acids are hydroxyproline, cystine, glycine and serine. Results obtained by gel filtration in 6m-guanidinium chloride on Sepharose 4B suggest that it has a subunit mol.wt. of about 30000 and that it probably associates into dimers. The lectin is inhibited specifically by chitin oligosaccharides and bacterial-cell-wall oligosaccharides, but only weakly by N-acetylglucosamine. Glycopeptides from soya-bean (Glycine max) lectin and fetuin are also strong inhibitors of Datura lectin, indicating that it interacts with internal N-acetylglucosamine residues. Its specificity is similar to, but not identical with, that of potato (Solanum tuberosum) lectin. After prolonged proteolytic digestion of reduced and S-carboxymethylated or S-aminoethylated derivatives of the lectin, glycopeptides of mol.wt. of about 18000 were isolated. The glycopeptides contained all the carbohydrate and hydroxyproline of the original glycoprotein, and lesser amounts of serine, S-carboxymethylcysteine and other amino acids. The arabinose residues of the glycoprotein are present as beta-l-arabinofuranosides linked to the polypeptide chain through the hydroxyproline residues, and can be removed by mild acid treatment; the ratio of arabinose to hydroxyproline is 3.4:1. Some of the serine residues of the polypeptide chain are substituted with one or two alpha-galactopyranoside residues, most of which can be removed by the action of alpha-galactosidase. The galactose residues are more easily removed from the acid-treated glycopeptide (from which arabinose has been removed) than from the complete glycopeptide, indicating a steric hindrance of the galactosidase action by the adjacent chains of arabinosides. There is a slow release of galactose residues by a process of beta-elimination in 0.5m-NaOH (pH13.7) from the complete glycopeptide, and a fairly rapid release of galactose by this process from the acid-treated glycopeptide, which lacks arabinose. This is probably due to the inhibitory effect of the negative charge on the adjacent arabinofuranoside residues. The similarities and differences between the lectins from Datura and potato are discussed, as are their structural resemblance to glycopeptides that have been isolated from plant cell walls.

Tissue and subcellular distribution of the lectin from Datura stramonium (thorn apple).

Plants of Datura stramonium (thorn-apple) were dissected into their component tissues and examined for the presence of the Datura lectin. This lectin was easily detected in seeds and in various parts of the flowers of adult plants. Traces were also found in green (emerged) cotyledons and roots of seedlings. The specific lectin activity in seeds contained within the fruits increased as the seeds matured. Mature seeds were homogenized in sucrose and separated by differential centrifugation into four fractions, three of which were clearly of distinct composition. Most of the lectin activity sedimented with the low-speed (cell-wall/protein-body) pellet, but a similar specific activity was recovered from the other fractions. However, if EDTA was included in the homogenization medium, three or four times more lectin activity was recovered in the soluble fraction. Immunofluorescent staining of formaldehyde-fixed sections showed that the lectin was localized in the cytoplasm, with little associated with cell walls. The possible relevance of these results to the function of the lectin in plant cells is discussed.

Purification of the lectin from Datura stramonium.

The lectin from Datura stramonium can be inhibited by oligomers of N-acetylglucosamine. This property was exploited to purify the lectin by affinity chromatography on Sepharosefetuin. The purified lectin is a glycoprotein in having subunits of 40 000 and 45 000 mol.wt.