Swertia
Gentiana
Phylogeography
Ectopic expression of carpel-specific MADS box genes from lily and lisianthus causes similar homeotic conversion of sepal and petal in Arabidopsis. (1/20)
Two MADS box genes, Lily MADS Box Gene 2 (LMADS2) and Eustoma grandiflorum MADS Box Gene 1 (EgMADS1), with an extensive similarity to the petunia (Petunia hybrida) FLORAL BINDING PROTEIN 7/11 and Arabidopsis AGL11, were characterized from the lily (Lilium longiflorum) and lisianthus (Eustoma grandiflorum). The expression of LMADS2 and EgMADS1 mRNA was restricted to the carpel and was absent in the other flower organs or vegetative leaves. LMADS2 mRNA was detected mainly in ovules and weakly in style tissues of the carpel, whereas EgMADS1 mRNA was only expressed in the ovules. Transgenic Arabidopsis plants ectopically expressing LMADS2 or EgMADS1 showed similar novel phenotypes resembling 35S::AGAMOUS plants by significantly reducing plant size, flowering early, and losing inflorescence indeterminacy. Ectopic expression of these two genes also generated similar ap2-like flowers by inducing homeotic conversion of the sepals into carpel-like structures in which stigmatic papillae and ovules were observed. In addition, the petals were converted into stamen-like structures in the second whorl of 35S::LMADS2 and 35S::EgMADS1 transgenic Arabidopsis. Our data indicated that LMADS2 and EgMADS1 are putative D functional MADS box genes in lily and lisianthus with a function similar to C functional genes once ectopically expressed in Arabidopsis. (+info)Phenylalanine-independent biosynthesis of 1,3,5,8-tetrahydroxyxanthone. A retrobiosynthetic NMR study with root cultures of Swertia chirata. (2/20)
Root cultures of Swertia chirata (Gentianaceae) were grown with supplements of [1-13C]glucose, [U-13C6]glucose or [carboxy-13C]shikimic acid. 1,3,5,8-Tetrahydroxyxanthone was isolated and analysed by quantitative NMR analysis. The observed isotopomer distribution shows that 1,3,5,8-tetrahydroxyxanthone is biosynthesized via a polyketide-type pathway. The starter unit, 3-hydroxybenzoyl-CoA, is obtained from an early shikimate pathway intermediate. Phenylalanine, cinnamic acid and benzoic acid were ruled out as intermediates. (+info)Morphological and ultrastructural diversity of orbicules in Gentianaceae. (3/20)
Minute granules of sporopollenin, called orbicules, can be observed on the innermost tangential and/or radial walls of secretory tapetum cells. Orbicules were investigated in 53 species of 34 Gentianaceae genera using light microscopy, scanning electron microscopy and transmission electron microscopy. This selection covered all different tribes and subtribes recognized in Gentianaceae (87 genera, +/-1650 species). Orbicules were found in 38 species (23 genera) distributed among the six tribes recognized in Gentianaceae. The orbicule typology is based on those described previously in Rubiaceae. Of the six orbicule types described previously, Type II orbicules are lacking. Type III orbicules are most common (17 species). Hockinia Gardner is the only representative with Type I orbicules. The number of representatives with orbicules belonging to the other orbicule types are equally distributed among the species studied: seven species possess Type IV orbicules, six species Type V and six species Type VI. The systematic usefulness of this typology is discussed in comparison with the latest systematic insights within the family, and palynological trends in Gentianaceae. Orbicule data have proven to be useful for evaluating tribal delimitation within Rubiaceae and Loganiaceae s.l.; however, they seem not to be useful for tribal delimitation in Gentianaceae. In the tribes Potalieae and Gentianeae orbicule data may be useful at subtribal level. (+info)The pollination ecology of an assemblage of grassland asclepiads in South Africa. (4/20)
The KwaZulu-Natal region of South Africa hosts a large diversity of asclepiads (Apocynaceae: Asclepiadoideae), many of which are endemic to the area. The asclepiads are of particular interest because of their characteristically highly evolved floral morphology. During 3 months of fieldwork (November 2000 to January 2001) the flower visitors and pollinators to an assemblage of nine asclepiads at an upland grassland site were studied. These observations were augmented by laboratory studies of flower morphology (including scanning electron microscopy) and flower colour (using a spectrometer). Two of the specialized pollination systems that were documented are new to the asclepiads: fruit chafer pollination and pompilid wasp pollination. The latter is almost unique in the angiosperms. Taxa possessing these specific pollination systems cluster together in multidimensional phenotype space, suggesting that there has been convergent evolution in response to similar selection to attract identical pollinators. Pollination niche breadth varied from the very specialized species, with only one pollinator, to the more generalized, with up to ten pollinators. Pollinator sharing by the specialized taxa does not appear to have resulted in niche differentiation in terms of the temporal or spatial dimensions, or with regards to placement of pollinaria. Nestedness analysis of the data set showed that there was predictability and structure to the pattern of plant-pollinator interactions, with generalist insects visiting specialized plants and vice versa. The research has shown that there is still much to be learned about plant-pollinator interactions in areas of high plant diversity such as South Africa. (+info)Molecular systematics and biogeography of Crawfurdia, Metagentiana and Tripterospermum (Gentianaceae) based on nuclear ribosomal and plastid DNA sequences. (5/20)
BACKGROUND AND AIMS: The systematic position of the genus Metagentiana and its phylogenetic relationships with Crawfurdia, Gentiana and Tripterospermum have not been explicitly addressed. These four genera belong to one of two subtribes (Gentianinae) of Gentianeae. The aim of this paper is to examine the systematic position of Crawfurdia, Metagentiana and Tripterospermum and to clarify their phylogenetic affinities more clearly using ITS and trnL intron sequences. METHODS: Nucleotide sequences from the internal transcribed spacers (ITS) of nuclear ribosomal DNA and the plastid DNA trnL (UAA) intron were analysed phylogenetically. Ten of fourteen Metagentiana species were sampled, together with 40 species of other genera in the subtribe Gentianinae. KEY RESULTS: The data support several previously published conclusions relating to the separation of Metagentiana from Gentiana and its closer relationships to Crawfurdia and Tripterospermum based on studies of gross morphology, floral anatomy, chromosomes, palynology, embryology and previous molecular data. The molecular clock hypothesis for the tested sequences in subtribe Gentianinae was not supported by the data (P < 0.05), so the clock-independent non-parametric rate smoothing method was used to estimate divergence time. This indicates that the separation of Crawfurdia, Metagentiana and Tripterospermum from Gentiana occurred about 11.4-21.4 Mya (million years ago), and the current species of these three genera diverged at times ranging from 0.4 to 6.2 Mya. CONCLUSIONS: The molecular analyses revealed that Crawfurdia, Metagentiana and Tripterospermum do not merit status as three separate genera, because sampled species of Crawfurdia and Tripterospermum are embedded within Metagentiana. The speciation and rapid radiation of these three genera is likely to have occurred in western China as a result of upthrust of the Himalayas during the late Miocene and the Pleistocene. (+info)Enicostemma littorale Blume aqueous extract improves the antioxidant status in alloxan-induced diabetic rat tissues. (6/20)
This study investigates the effect of oral administration of an aqueous Enicostemma littorale whole plant extract on antioxidant defense in alloxan-induced diabetes in rats. A significant increase in blood glucose and increased concentration of thiobarbituric acid reactive substances (TBARS) and hydroperoxides (HP) in liver, kidney and pancreas were observed in alloxan diabetic rats. Decreased concentration of reduced glutathione (GSH) and decreased activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) were also observed in these tissues of diabetic rats. Oral administration of aqueous E. littorale whole plant extract (1 and 2 g/kg) to diabetic rats daily for 45 days significantly decreased blood glucose, TBARS, HP and increased GSH, SOD, catalase and GPx. E. littorale extract at the dose of 2 g/kg was more effective than 1 g/kg. Insulin (6 units/kg) administration to diabetic rats for 45 days brought back all the parameters to near normal status. (+info)Nectar sugar composition and volumes of 47 species of Gentianales from a southern Ecuadorian montane forest. (7/20)
BACKGROUND AND AIMS: This study investigates 47 taxonomically related species (Gentianales), all native to a tropical montane forest in southern Ecuador, in terms of nectar chemistry and nectar volumes in relation to pollination biology. METHODS: Nectar volumes of covered (24-h production) and uncovered (standing crop) flowers were measured in the natural habitat. Sucrose, fructose and glucose were quantified in the nectar using high performance liquid chromatography. Flower visitors were observed. KEY RESULTS: Nectar sugar concentration did not differ significantly among the pollination syndromes. Regarding sugar composition, the only significant differences were found in chiropterophilous and myiophilous flowers, which had a significantly lower sugar ratio than sphingophilous flowers. A separation of chiropterophilous and myiophilous flowers from the other pollination syndromes is further substantiated by non-linear multidimensional scaling using the chord-normalized expected species shared index of dissimilarity based on nectar sugar compositions. The matrix test revealed no correlation of observed floral visitors to nectar concentrations; however, a weak significant correlation was found between floral visitors and nectar sugar compositions. The nectar volumes of covered and uncovered flowers are related to, and differ significantly among, pollination syndromes. Matrix tests revealed correlation between floral visitors and nectar volume of covered flowers and, to a lesser extent, of uncovered flowers. CONCLUSIONS: Sucrose is the predominant floral nectar sugar in the order Gentianales, suggesting that nectar sugar composition is a conservative characteristic. However, some degree of an adaptive convergence of floral nectar compositions to principal pollinator type within the constraints set by phylogenetic history is likely. The driving force to visitation appears to be the volume of nectar the visitor can expect to consume. (+info)New insight into the structures and formation of anthocyanic vacuolar inclusions in flower petals. (8/20)
BACKGROUND: Although the biosynthetic pathways for anthocyanins and their regulation have been well studied, the mechanism of anthocyanin accumulation in the cell is still poorly understood. Different models have been proposed to explain the transport of anthocyanins from biosynthetic sites to the central vacuole, but cellular and subcellular information is still lacking for reconciliation of different lines of evidence in various anthocyanin sequestration studies. Here, we used light and electron microscopy to investigate the structures and the formation of anthocyanic vacuolar inclusions (AVIs) in lisianthus (Eustoma grandiflorum) petals. RESULTS: AVIs in the epidermal cells of different regions of the petal were investigated. Three different forms of AVIs were observed: vesicle-like, rod-like and irregular shaped. In all cases, EM examinations showed no membrane encompassing the AVI. Instead, the AVI itself consisted of membranous and thread structures throughout. Light and EM microscopy analyses demonstrated that anthocyanins accumulated as vesicle-like bodies in the cytoplasm, which themselves were contained in prevacuolar compartments (PVCs). The vesicle-like bodies seemed to be transported into the central vacuole through the merging of the PVCs and the central vacuole in the epidermal cells. These anthocyanin-containing vesicle-like bodies were subsequently ruptured to form threads in the vacuole. The ultimate irregular AVIs in the cells possessed a very condensed inner and relatively loose outer structure. CONCLUSION: Our results strongly suggest the existence of mass transport for anthocyanins from biosynthetic sites in the cytoplasm to the central vacuole. Anthocyanin-containing PVCs are important intracellular vesicles during the anthocyanin sequestration to the central vacuole and these specific PVCs are likely derived directly from endoplasmic reticulum (ER) in a similar manner to the transport vesicles of vacuolar storage proteins. The membrane-like and thread structures of AVIs point to the involvement of intravacuolar membranes and/or anthocyanin intermolecular association in the central vacuole. (+info)Gentianaceae is not a medical term, but a taxonomic category in botany. It refers to the family of plants that includes gentians and related genera. These plants are known for their beautiful, often brightly colored flowers, and are found primarily in temperate and subtropical regions around the world.
Some species of Gentianaceae have been used in traditional medicine for their purported therapeutic properties. For example, gentian root has been used as a bitter tonic to stimulate digestion and appetite, and to treat various gastrointestinal disorders. However, it's important to note that the use of these plants in medical treatment should be based on scientific evidence and under the guidance of a qualified healthcare professional.
"Swertia" is a genus of flowering plants in the family Gentianaceae. It includes around 150 species, many of which are native to Asia and have been used in traditional medicine for their potential health benefits. Some active compounds found in Swertia species include xanthones, swerioside, and amarogentin, which have been studied for their anti-inflammatory, antioxidant, and antimicrobial properties. However, more research is needed to fully understand the potential medicinal uses and safety of these plants. It's important to consult with a healthcare professional before using any herbal remedies.
"Gentiana" is a term that refers to a genus of plants in the family Gentianaceae. These plants are often characterized by their beautiful, trumpet-shaped flowers and are found primarily in the Northern Hemisphere, with some species located in tropical mountains in Africa and South America. The name "Gentiana" comes from the Illyrian king Genius, who is said to have discovered the medicinal properties of this plant.
In a medical context, certain species of Gentiana have been used in traditional medicine for their anti-inflammatory, antipyretic, and bitter digestive stimulant properties. For example, Gentiana lutea (yellow gentian) is commonly used in herbal medicine to treat digestive disorders such as loss of appetite, heartburn, and flatulence. However, it's important to note that the use of Gentiana in modern medicine is not well-studied, and more research is needed to establish its safety and efficacy.
It's worth noting that "Gentiana" is primarily a botanical term and is not commonly used as a medical diagnosis or treatment. If you have any health concerns, it's always best to consult with a qualified healthcare professional for advice.
Phylogeography is not a medical term, but rather a subfield of biogeography and phylogenetics that investigates the spatial distribution of genealogical lineages and the historical processes that have shaped them. It uses genetic data to infer the geographic origins, dispersal routes, and demographic history of organisms, including pathogens and vectors that can affect human health.
In medical and public health contexts, phylogeography is often used to study the spread of infectious diseases, such as HIV/AIDS, influenza, or tuberculosis, by analyzing the genetic diversity and geographic distribution of pathogen isolates. This information can help researchers understand how diseases emerge, evolve, and move across populations and landscapes, which can inform disease surveillance, control, and prevention strategies.
The ribosomal spacer in DNA refers to the non-coding sequences of DNA that are located between the genes for ribosomal RNA (rRNA). These spacer regions are present in the DNA of organisms that have a nuclear genome, including humans and other animals, plants, and fungi.
In prokaryotic cells, such as bacteria, there are two ribosomal RNA genes, 16S and 23S, separated by a spacer region known as the intergenic spacer (IGS). In eukaryotic cells, there are multiple copies of ribosomal RNA genes arranged in clusters called nucleolar organizer regions (NORs), which are located on the short arms of several acrocentric chromosomes. Each cluster contains hundreds to thousands of copies of the 18S, 5.8S, and 28S rRNA genes, separated by non-transcribed spacer regions known as internal transcribed spacers (ITS) and external transcribed spacers (ETS).
The ribosomal spacer regions in DNA are often used as molecular markers for studying evolutionary relationships among organisms because they evolve more rapidly than the rRNA genes themselves. The sequences of these spacer regions can be compared among different species to infer their phylogenetic relationships and to estimate the time since they diverged from a common ancestor. Additionally, the length and composition of ribosomal spacers can vary between individuals within a species, making them useful for studying genetic diversity and population structure.