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2,863 result(s) for "Chemotaxonomy"
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Characterization of Polyphenols from Schinus sp. Fruits
The Anacardiaceae (\"cashew family\") include a number of well-known edible species such as mango, pistachio, cashew, marula, sumach, and peppertree. This family is characterized by the presence of a broad profile of polyphenols, which are secondary metabolites that protect plants from biotic and abiotic stress. This thesis addresses the phenolic composition of fruits of the Brazilian peppertree (Schinus terebinthifolius Raddi), which are used as a spice. Using LC-MS and 2D NMR spectroscopy, 30 phenolic compounds were described for S. terebinthifolius, many of them for the first time. The fruits of the closely related Peruvian peppertree (Schinus molle L.) were also characterized and a method for the phytochemical differentiation of the two spices was proposed. Based on these studies, chemotaxonomic traits within the Anacardiaceae could be established. Furthermore, the pressurized liquid extraction of polyphenols was optimized and a multi-step process was presented, which allows the purification and isolation of bioactive compounds from Schinus species for future use in bioassays. In conclusion, this work provides novel insights into the phenolic profile of these fruits and paves the way for further investigations into their bio-functional and techno-functional properties.
Thailand’s amazing diversity: up to 96% of fungi in northern Thailand may be novel
Fungi have been often neglected, despite the fact that they provided penicillin, lovastatin and many other important medicines. They are an understudied, but essential, fascinating and biotechnologically useful group of organisms. The study of fungi in northern Thailand has been carried out by us since 2005. These studies have been diverse, ranging from ecological aspects, phylogenetics with the incorportation of molecular dating, taxonomy (including morphology and chemotaxonomy) among a myriad of microfungi, to growing novel mushrooms, and DNA-based identification of plant pathogens. In this paper, advances in understanding the biodiversity of fungi in the region are discussed and compared with those further afield. Many new species have been inventoried for the region, but many unknown species remain to be described and/or catalogued. For example, in the edible genus Agaricus, over 35 new species have been introduced from northern Thailand, and numerous other taxa await description. In this relatively well known genus, 93% of species novelty is apparent. In the microfungi, which are relatively poorly studied, the percentage of novel species is, surprisingly, generally not as high (55–96%). As well as Thai fungi, fungi on several hosts from Europe have been also investigated. Even with the well studied European microfungi an astounding percentage of new taxa (32–76%) have been discovered. The work is just a beginning and it will be a daunting task to document this astonishingly high apparent novelty among fungi.
Donald Pinkava's journey from Asteraceae to Cactaceae: from the Ohio State University to Arizona State University
Donald J. Pinkava is best known for his application of cytogenetics in unraveling the complex interspecific hybridization in the prickly pear genus Opuntia Mill. in the southwestern United States extending down into northern and central Mexico. Using cytogenetics, Pinkava delimited species boundaries within Opuntia for taxonomic treatments. His work on Opuntia in the Chihuahuan Desert led to later comprehensive contributions in the Flora of North America and the Flora of Arizona that include opuntias not only in the Southwest but in every US state. Pinkava's systematic knowledge, as reflected in his taxonomic treatments provided the basic scientific framework needed for ongoing conservation of Cactaceae in the Southwest to the present day. Interestingly, the starting point for all of Pinkava's contributions in Cactaceae began with his initial studies of Asteraceae as a student of T. Richard Fisher at The Ohio State University (OSU), an institution with longstanding research interests in the Asteraceae. It is there that he selected a genus, Berlandiera DC as his dissertation topic. Ironically, this genus has a range from the drier sites of the Eastern Coastal Plains, into the Ozark and Ouachita Mountains, with a disjunct distribution in the mountain floras of southeastern Arizona and Northern Mexico. Like Berlandiera, Pinkava’s own work reflects techniques and training in the eastern US, that migrated and was used as the basis for his groundbreaking studies of Cactaceae in the Southwest.
Molecular phylogenetic analyses redefine seven major clades and reveal 22 new generic clades in the fungal family Boletaceae
Mushrooms in the basidiomycete family Boletaceae are ecologically and economically very important. However, due to the morphological complexity and the limited phylogenetic information on the various species and genera of this fungal family, our understanding of its systematics and evolution remains rudimentary. In this study, DNA sequences of four genes (nrLSU, tef1 -α, rpb1 , and rpb2 ) were newly obtained from ca. 200 representative specimens of Boletaceae . Our phylogenetic analyses revealed seven major clades at the subfamily level, namely Austroboletoideae , Boletoideae , Chalciporoideae , Leccinoideae , Xerocomoideae , Zangioideae , and the Pulveroboletus Group. In addition, 59 genus-level clades were identified, of which 22 were uncovered for the first time. These 22 clades were mainly placed in Boletoideae and the Pulveroboletus Group. The results further indicated that the characters frequently used in the morphology-based taxonomy of Boletaceae , such as basidiospore ornamentation, the form of the basidioma, and the stuffed pores each had multiple origins within the family, suggesting that the use of such features for high-level classification of Boletaceae should be de-emphasized and combined with other characters.
Linarin, a Glycosylated Flavonoid, with Potential Therapeutic Attributes: A Comprehensive Review
Many flavonoids, as eminent phenolic compounds, have been commercialized and consumed as dietary supplements due to their incredible human health benefits. In the present study, a bioactive flavone glycoside linarin (LN) was designated to comprehensively overview its phytochemical and biological properties. LN has been characterized abundantly in the Cirsium, Micromeria, and Buddleja species belonging to Asteraceae, Lamiaceae, and Scrophulariaceae families, respectively. Biological assessments exhibited promising activities of LN, particularly, the remedial effects on central nervous system (CNS) disorders, whereas the remarkable sleep enhancing and sedative effects as well as AChE (acetylcholinesterase) inhibitory activity were highlighted. Of note, LN has indicated promising anti osteoblast proliferation and differentiation, thus a bone formation effect. Further biological and pharmacological assessments of LN and its optimized semi-synthetic derivatives, specifically its therapeutic characteristics on osteoarthritis and osteoporosis, might lead to uncovering potential drug candidates.
Pollen sterols are associated with phylogeny and environment but not with pollinator guilds
• Phytosterols are primary plant metabolites that have fundamental structural and regulatory functions. They are also essential nutrients for phytophagous insects, including pollinators, that cannot synthesize sterols. Despite the well-described composition and diversity in vegetative plant tissues, few studies have examined phytosterol diversity in pollen. • We quantified 25 pollen phytosterols in 122 plant species (105 genera, 51 families) to determine their composition and diversity across plant taxa. We searched literature and databases for plant phylogeny, environmental conditions, and pollinator guilds of the species to examine the relationships with pollen sterols. • 24-methylenecholesterol, sitosterol and isofucosterol were the most common and abundant pollen sterols. We found phylogenetic clustering of twelve individual sterols, total sterol content and sterol diversity, and of sterol groupings that reflect their underlying biosynthesis pathway (C-24 alkylation, ring B desaturation). Plants originating in tropical-like climates (higher mean annual temperature, lower temperature seasonality, higher precipitation in wettest quarter) were more likely to record higher pollen sterol content. However, pollen sterol composition and content showed no clear relationship with pollinator guilds. • Our study is the first to show that pollen sterol diversity is phylogenetically clustered and that pollen sterol content may adapt to environmental conditions.
Thin-Layer Chromatography (TLC) in the Screening of Botanicals–Its Versatile Potential and Selected Applications
The aim of this paper is to present a comprehensive overview of the main aims and scopes in screening of botanicals, a task of which thin-layer chromatography (TLC) is, on an everyday basis, confronted with and engaged in. Stunning omnipresence of this modest analytical technique (both in its standard format (TLC) and the high-performance one (HPTLC), either hyphenated or not) for many analysts might at a first glance appear chaotic and random, with an auxiliary rather than leading role in research, and not capable of issuing meaningful final statements. Based on these reflections, our purpose is not to present a general review paper on TLC in screening of botanicals, but a blueprint rather (illustrated with a selection of practical examples), which highlights a sovereign and important role of TLC in accomplishing the following analytical tasks: (i) solving puzzles related to chemotaxonomy of plants, (ii) screening a wide spectrum of biological properties of plants, (iii) providing quality control of herbal medicines and alimentary and cosmetic products of biological origin, and (iv) tracing psychoactive plants under forensic surveillance.
Taxonomically Informed Scoring Enhances Confidence in Natural Products Annotation
Mass spectrometry (MS) offers unrivalled sensitivity for the metabolite profiling of complex biological matrices encountered in natural products (NP) research. The massive and complex sets of spectral data generated by such platforms require computational approaches for their interpretation. Within such approaches, computational metabolite annotation automatically links spectral data to candidate structures via a score, which is usually established between the acquired data and experimental or theoretical spectral databases (DB). This process leads to various candidate structures for each MS features. However, at this stage, obtaining high annotation confidence level remains a challenge notably due to the extensive chemodiversity of specialized metabolomes. The design of a metascore is a way to capture complementary experimental attributes and improve the annotation process. Here, we show that integrating the taxonomic position of the biological source of the analyzed samples and candidate structures enhances confidence in metabolite annotation. A script is proposed to automatically input such information at various granularity levels (species, genus, and family) and complement the score obtained between experimental spectral data and output of available computational metabolite annotation tools (ISDB-DNP, MS-Finder, Sirius). In all cases, the consideration of the taxonomic distance allowed an efficient re-ranking of the candidate structures leading to a systematic enhancement of the recall and precision rates of the tools (1.5- to 7-fold increase in the F1 score). Our results clearly demonstrate the importance of considering taxonomic information in the process of specialized metabolites annotation. This requires to access structural data systematically documented with biological origin, both for new and previously reported NPs. In this respect, the establishment of an open structural DB of specialized metabolites and their associated metadata, particularly biological sources, is timely and critical for the NP research community.
The Essential Oil Compositions of Three Teucrium Taxa Growing Wild in Sicily: HCA and PCA Analyses
The chemical composition and the qualitative and quantitative variability of the essential oils of three taxa belonging to the Teucrium genus were studied. The investigated taxa, that grow wild in Sicily, were Teucrium flavum L. (section Chamaedrys (Mill.) Scheb.), Teucrium montanum and Teucrium capitatum L. of section Polium (Mill.) Scheb. Essential oils were extracted by hydrodistillation and analyzed by GC-MS. In total, 74 compounds were identified. Sesquiterpene hydrocarbons were found to be the main group for T. flavum (48.3%). T. capitatum consisted essentially of monoterpene hydrocarbons (72.7%), with α-pinene (19.9%), β-pinene (27.6%) and sylvestrene (16.6%) as the most abundant compounds whereas ledene oxide (12.1%), epiglobulol (13.5%) and longifolenaldehyde (14.5%) were identified as the main constituents among the oxygenated sesquiterpenes (63.5%) of T. montanum. Furthermore, a complete literature review on the composition of the essential oils of all the other accessions of these Teucrium taxa, studied so far, was performed. Hierarchical Cluster Analysis (HCA) and Principal Component Analyses (PCA) were used in order to demonstrate geographical variations in the composition of the essential oils.
Resurrection and emendation of the Hypoxylaceae, recognised from a multigene phylogeny of the Xylariales
A multigene phylogeny was constructed, including a significant number of representative species of the main lineages in the Xylariaceae and four DNA loci the internal transcribed spacer region (ITS), the large subunit (LSU) of the nuclear rDNA, the second largest subunit of the RNA polymerase II (RPB2), and beta-tubulin (TUB2). Specimens were selected based on more than a decade of intensive morphological and chemotaxonomic work, and cautious taxon sampling was performed to cover the major lineages of the Xylariaceae; however, with emphasis on hypoxyloid species. The comprehensive phylogenetic analysis revealed a clear-cut segregation of the Xylariaceae into several major clades, which was well in accordance with previously established morphological and chemotaxonomic concepts. One of these clades contained Annulohypoxylon, Hypoxylon, Daldinia, and other related genera that have stromatal pigments and a nodulisporium-like anamorph. They are accommodated in the family Hypoxylaceae, which is resurrected and emended. Representatives of genera with a nodulisporium-like anamorph and bipartite stromata, lacking stromatal pigments (i.e. Biscogniauxia, Camillea, and Obolarina) appeared in a clade basal to the xylarioid taxa. As they clustered with Graphostroma platystomum, they are accommodated in the Graphostromataceae. The new genus Jackrogersella with J. multiformis as type species is segregated from Annulohypoxylon. The genus Pyrenopolyporus is resurrected for Hypoxylon polyporus and allied species. The genus Daldinia and its allies Entonaema, Rhopalostroma, Ruwenzoria, and Thamnomyces appeared in two separate subclades, which may warrant further splitting of Daldinia in the future, and even Hypoxylon was divided in several clades. However, more species of these genera need to be studied before a conclusive taxonomic rearrangement can be envisaged. Epitypes were designated for several important species in which living cultures and molecular data are available, in order to stabilise the taxonomy of the Xylariales.