Structural Characterization of Lignin in Four Cacti Wood: Implications of Lignification in the Growth Form and Succulence

Wood lignin composition strongly depends on anatomical features and it has been used as a marker for characterizing major plant groups. Wood heterogeneity in Cactaceae is involved in evolutionary and adaptive processes within this group; moreover, it is highly correlated to the species growth form. Here we studied the lignin structure from different types of woods in four Cactaceae species with different stem morphologies (Pereskia lychnidiflora, tree/fibrous wood; Opuntia streptacantha and Pilosocereus chrysacanthus, tree/succulent fibrous wood; Ferocactus hamatacanthus, cylindrical stem/dimorphic wood) in order to determine their relationship with the wood anatomy in an evolutionary-adaptive context. Dioxane lignin was isolated and analyzed by pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS), two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR) and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The main linkages are the β-O−4′ ether (67–85%), the β-β′ resinol (10–26%) and the β-5′ and α-O−4′ linkages of the phenylcoumaran structures (≤7%). Spirodienone structures have a considerable abundance (5%) in the dimorphic wood of F. hamatacanthus. In addition, low contents (≤3%) of α,β-diaryl ether, α-oxidized β-O−4′ ether and dibenzodioxocin structures were found. The sinapyl- and coniferyl acetates are not part of the wood lignin in any of the studied species. The low (≤5%) γ-acetylation in the F. hamatacanthus and P. chrysacanthus wood lignin is here interpreted as an evidence of a high specialization of the wood elements in the conduction/storage of water. The lignin of the studied Cactaceae is composed predominantly of guaiacyl and syringyl units (S/G: 0.9–16.4). High abundance of syringyl units (62–94%) in three of the four species is considered as a defense mechanism against oxidative agents, it is a very conspicuous trait in the most succulent species with dimorphic wood. Furthermore, it is also associated with ferulates and the herein called γ-acetylated guaiacyl-syringaresinol complexes acting as nucleation sites for lignification and as cross-links between lignin and carbohydrates at the wide-band tracheid-fiber junctions

Anatomía de la madera de especies de Forestiera (Oleaceae) en México

Background and Aims: One of the most recent approaches to delimiting plant species is using anatomical wood characters in woody taxa, which has been little explored in Mexican representatives. The genera Forestiera is an example of this, since only the wood of two of the 12 species distributed in Mexico have been described. With the aim of contributing to the knowledge of the wood anatomy of the genera, as well as the search for anatomical characters that discriminate between their species, this study describes the wood anatomy of the wood of eight species of Forestiera distributed in Mexico, with a systematic approach. Methods: Wood from 42 wood samples from eight species were analyzed, with three individuals per species at 14 collection sites. The material was processed with conventional microtechniques to obtain qualitative and quantitative anatomical variables. Characters were evaluated with multivariate statistics to determine which ones are important to form groups of species in Forestiera. Key results: Some previously reported anatomical attributes agree with those observed in this paper. However, there are differences such as semi-ring porous wood and growth marks without marginal parenchyma. The analyses formed groups of species, based the diameter of early-wood vessels, length of vessel elements and fibers, diameter of the fibers, type of rays, abundance of the marginal parenchyma and the type of crystals in rays. Based on wood anatomy, a taxonomic key is proposed to identify the studied species. Conclusions: Through the used analyses, we contribute to the knowledge of Forestiera anatomy. Wood characters that allow to distinguish groups of species are recognized. Future studies will confirm their taxonomic value.Antecedentes y Objetivos: Uno de los enfoques más recientes para delimitar especies vegetales es el uso de caracteres anatómicos de la madera en representantes leñosos que ha sido poco explorado en taxones mexicanos. El género Forestiera (Oleaceae) es un ejemplo de esto, pues solo se ha descrito la madera de dos de las 12 especies distribuidas en México. Con el objetivo de contribuir al conocimiento de la anatomía de la madera del género, así como a la búsqueda de caracteres anatómicos que discriminen entre sus especies, en el presente estudio se describe la anatomía de la madera de ocho especies de Forestiera distribuidas en México con un enfoque sistemático. Métodos: Se analizaron 42 muestras de madera de ocho especies, provenientes de tres individuos por especie en 14 sitios de colecta. El material se procesó con microtecnia convencional para obtener variables anatómicas cualitativas y cuantitativas. Estas fueron evaluadas con estadística multivariada para determinar cuáles son importantes para formar grupos de especies en Forestiera. Resultados clave: Algunos atributos anatómicos reportados anteriormente coinciden con los observados en este trabajo. Sin embargo, hay diferencias como la porosidad semianular y la delimitación de marcas de crecimiento sin presencia de parénquima marginal. Los análisis formaron grupos de especies dados por el diámetro de vasos de la madera temprana, longitud de elementos de vaso y fibras, diámetro de las fibras, tipo de radios, abundancia del parénquima marginal y tipo de cristales en los radios. Con base en la anatomía de la madera, se propone una clave taxonómica para identificar las especies estudiadas. Conclusiones: Mediante los análisis empleados se contribuye al conocimiento de la anatomía de la madera de Forestiera; además, se reconocen caracteres que permiten distinguir grupos de especies. Futuros estudios confirmarán su valor taxonómico

Mis casos clínicos de especialidades odontológicas

Libro que muestra la atención de casos clínicos particulares referente a las diferentes especialidades odontológicasLibro que muestra la atención de casos clínicos particulares referente a las diferentes especialidades odontológicasUniversidad Autónoma de Campeche Universidad Autónoma del Estado de Hidalgo Universidad Autónoma del Estado de Méxic

Efecto de la esterilización sobre compuestos bioactivos de los extractos del fruto xoconostle ulapa (opuntia oligacantha) y de la planta sangre de drago (jatropha dioica sessé ex cerv.) con posible aplicación antimicrobiana en productos bucales.

Los extractos naturales han sido empleados como agentes antimicrobianos ante un gran número de microrganismos patógenos, los extractos de los rizomas de la planta “sangre de drago” (Jatropha dioica) y del fruto del xoconostle "Ulapa" (Opuntia oligacantha) se encuentran entre estos agentes. Sin embargo, para incluirlos en formulaciones alimentarias o farmacéuticas es necesario eliminar su microbiota natural o adquirida durante el proceso de su extracción, mediante métodos de esterilización. Por otro lado, los efectos de la esterilización por filtración y autoclave sobre sus propiedades no han sido evaluados

Wood Chemical Composition in Species of Cactaceae: The Relationship between Lignification and Stem Morphology

<div><p>In Cactaceae, wood anatomy is related to stem morphology in terms of the conferred support. In species of cacti with dimorphic wood, a unique process occurs in which the cambium stops producing wide-band tracheids (WBTs) and produces fibers; this is associated with the aging of individuals and increases in size. Stem support and lignification have only been studied in fibrous tree-like species, and studies in species with WBTs or dimorphic wood are lacking. In this study, we approach this process with a chemical focus, emphasizing the role of wood lignification. We hypothesized that the degree of wood lignification in Cactaceae increases with height of the species and that its chemical composition varies with wood anatomy. To test this, we studied the chemical composition (cellulose, hemicellulose, and lignin content) in 13 species (2 WBTs wood, 3 dimorphic, and 8 fibrous) with contrasting growth forms. We also analyzed lignification in dimorphic and fibrous species to determine the chemical features of WBTs and fibers and their relationship with stem support. The lignin contents were characterized by Fourier transform infrared spectroscopy and high performance liquid chromatography. We found that 11 species have a higher percentage (>35%) of lignin in their wood than other angiosperms or gymnosperms. The lignin chemical composition in fibrous species is similar to that of other dicots, but it is markedly heterogeneous in non-fibrous species where WBTs are abundant. The lignification in WBTs is associated with the resistance to high water pressure within cells rather than the contribution to mechanical support. Dimorphic wood species are usually richer in syringyl lignin, and tree-like species with lignified rays have more guaiacyl lignin. The results suggest that wood anatomy and lignin distribution play an important role in the chemical composition of wood, and further research is needed at the cellular level.</p></div

Non fibrous wood in species of Cacteae, cross sections near the vascular cambium.

<p>(A) <i>Ariocarpus retusus</i>: less lignified wood with vessels embedded in a matrix of WBTs separated by non lignified dilated rays; (B) <i>Coryphantha clavata</i>: wood with vessels embedded in a matrix of WBTs and narrow non lignified rays; (C) <i>Echinocactus platyacanthus</i>: wood with vessels embedded in a matrix of fibers and axial parenchyma with wider lignified rays; (D) <i>Ferocactus hamatacanthus</i>: wood with vessels embedded in a matrix of WBTs and fibers in similar proportions and a few narrow non lignified rays; (E) <i>Ferocactus pilosus</i>: wood with vessels embedded in a matrix of WBTs and lignified rays near the pith; (F) <i>Ferocactus pilosus</i>: wood with vessels embedded in a matrix of fibers and non lignified rays near the vascular cambium. Bar is 550 μm in A, B; 200 μm in C, E, F; 100 μm in D; r = ray.</p

Effects of Sterilization on Bioactives of <em>Jatropha dioica</em> and <em>Opuntia oligacantha</em> Extracts, and on Antimicrobial Capacity against <em>Streptococcus mutans</em>

Natural extracts have been used as antimicrobial agents, and extracts of the rhizomes of the dragon’s blood plant (Jatropha dioica) and of the fruit of xoconostle ‘Ulapa’ (Opuntia oligacantha) are among these agents. To be able to use the extracts, it is necessary to eliminate their natural microbiota by the means of sterilization methods; however, the effects of thermal sterilization on their properties have not been evaluated. The objective of the study was to evaluate the physico-chemical, antioxidant, and antimicrobial properties of extracts of the rhizomes of dragon’s blood and the fruit of xoconostle, when not sterilized, and when sterilized by autoclaving. The contents of phenolic compounds, flavonoids, antioxidant, and antimicrobial activity against Streptococcus mutans were not affected in autoclave-sterilized extracts of dragon’s blood rhizomes, and naringenin, apigenin, galagina, vanillic, and caffeic acid were detected, while in autoclave-sterilized extracts of xoconostle fruits, the betalain content decreased, with galagin, gallic, vanillic, and p-coumaric acid being identified. The minimum inhibitory concentration for the extract sterilized by autoclaving dragon’s blood was 2 mg/mL, and for the extract sterilized by autoclaving xoconostle, it was 28 mg/mL. Both represent natural alternatives as antimicrobial agents against S. mutans.</i

Characteristics of individuals studied from thirteen species of Cactaceae, the regions of wood that were studied are indicated.

<p><b>Abbreviations.</b> Tuberculated (T), ribbed (R), tuberculated ribs (TR). Lower wood (LW): near to the vascular cambium (LWc), near to the pith (LWp). Upper wood (UW).</p><p>* In these dimorphic species occurs a change from WBTs wood in juvenile stages to fibrous wood in the mature ones.</p><p>Characteristics of individuals studied from thirteen species of Cactaceae, the regions of wood that were studied are indicated.</p

Fibrous wood in species of Cactaceae, cross sections, near the vascular cambium.

<p>Vessels embedded in a matrix of fibers with lignified rays except <i>Opuntia streptacantha</i>. (A) <i>Cylindropuntia imbricata</i>; (B) <i>Lophocereus marginatus</i>; (C) <i>Myrtillocactus geometrizans</i>; (D) <i>Opuntia streptacantha</i>: wood with vessels embedded in a matrix of fiber or parenchyma with intermixed WBTs and non lignified rays; (E) <i>Pereskia lychnidiflora</i>; (F) <i>Stenocereus dumortieri</i>. Bar is 200 μm; r = ray.</p