Search results for "RACE"
showing 10 items of 4458 documents
New oxygenated eudesmanolides from artemisia herba-alba
1990
Abstract The aerial parts of Artemisia herba-alba Asso subsp.valentina Lam. (Asteraceae) yielded the new eudesmanolides 1-11 and the new sesquiterpene-monoterpene adducts 12-13. The absolute configuration of compound 6 was confirmed with the aid of X-ray diffraction analysis. Some aspects of the thermal and photochemical reactivity of 2,4-cyclohexadienones are discussed.
The monophyly and evolution of Cynara L. (Asteraceae) sensu lato: evidence from the Internal Transcribed Spacer region of nrDNA
2005
The monophyly and evolution of Cynara was investigated using ITS sequence data. Parsimony analysis supports the monophyly of Cynara sensu lato, i.e. including the distinctive taxa C. humilis and C. tournefortii. This contradicts the recent decision to create a new monotypic genus Arcyna for C. tournefortii. A hypothesised close relationship between C. tournefortii and Silybum Adans. is also refuted. Four of the five species of Cynara, for which multiple accessions were sequenced, were shown to be monophyletic but C. baetica was found to be non-monophyletic. Free energy estimates for ITS1 secondary structure and conservation of the 5.8S region suggest that this is not due to the occurrence o…
Typification of two Linnaean names: Centaurea aspera and Centaurea isnardii (Asteraceae)
2014
The typification of the names Centaurea aspera L. and C. isnardii L. (Asteraceae) is discussed. A lectotype for C. aspera is designated from original material conserved in UPS-BURSER (Joachim Burser Herbarium). Centaurea isnardii is typified by an illustration of Isnard (1719) confirming this name as a synonym of C. aspera subsp. aspera.
Tipificación de Inula montana L. (Asteraceae)
2014
Ferrer-Gallego, P., E. Laguna, R. Rosello, J. Gomez & J. B. Peris (2014). Typification of Inula montana L. (Asteraceae). Candollea 69: 5–8. In Spanish, English and French abstracts.The name Inula montana L. (Asteraceae) is lecto- and epitypified. The designated lectotype corresponds to an icon from Robert Morison published in 1699 and the epitype to a plant specimen collected by Morison and conserved at OXF (Morisonian Herbarium).
Chemical composition and antimicrobial activity of some oleogum resin essential oils from Boswellia spp. (Burseraceae).
2007
The chemical composition of Boswellia carteri (Somalia), B. papyrifera (Ethiopia), B. serrata (India) and B. rivae (Ethiopia) oleogum resin essential oils was investigated using GC-MS to identify chemotaxonomy marker components. Total ion current peak areas gave good approximations to relative concentrations based on GC-MS peak areas. B. carteri and B. serrata oleogum resin oils showed similar chemical profiles, with isoincensole and isoincensole acetate as the main diterpenic components. Both n-octanol and n-octyl acetate, along with the diterpenic components incensole and incensole acetate, were the characteristic compounds of B. papyrifera oleogum resin oil. Hydrocarbon and oxygenated mo…
A revision of Gynura (Asteraceae: Senecioneae)
2011
A revision of the paleotropical genus Gynura Cass. is presented. Forty-four species are recognized, of which three are described as new. These are G. daviesiae Vanijajiva & Kadereit, G. villosa Vanijajiva & Kadereit, and G. siamensis Vanijajiva & Kadereit. Gynura dissecta (F. G. Davies) Vanijajiva & Kadereit, G. annua (F. G. Davies) Vanijajiva & Kadereit, and G. aurantiaca (Bl.) DC. subsp. parviflora (F. G. Davies) Vanijajiva & Kadereit are new combinations. An identification key, descriptions, and distribution maps are provided.
pH Homeostasis and Citric Acid Utilization: Differences Between Leuconostoc mesenteroides and Lactococcus lactis
1997
This study presents the effects of citric acid and extracellular pH (pHe) on the intracellular pH (pHi) of wild-type and citrate negative variants (cit−) Leuconostoc mesenteroides subsp. mesenteroides (Ln. mesenteroides M) and Lactococcus lactis subsp. lactis bv. diacetylactis (L. lactis LD). A recent method using a pH-sensitive fluorescent indicator carboxyfluorescein succinimidyl ester (cFSE) was adapted to measure the pHi of these two lactic acid bacteria in resting cells. Energized cells with 10 mM lactose of Ln. mesenteroides M and L. lactis LD modified their pH gradient (ΔpH) in the same manner; when the pHe was decreased from 7 to 4, the pHi decreased from 7 to about 5. The adjunctio…
Evolution of Cell Adhesion Systems: Evidence for Arg-Gly-Asp-Mediated Adhesion in the Protozoan Neoparamoeba aestuarina
1995
Developmental processes in multicellular organisms require structural elements, such as adhesion molecules, to stabilize cells at functional positions. In vertebrates, a series of extracellular matrix proteins, e.g. fibronectin and laminin, are involved in cell adhesion. These proteins contain Arg-Gly-Asp [RGD] at their binding sites. Here we show that at concentrations above 2 mM the peptide GRGDSPK, comprising the tripeptide RGD (Arg-Gly-Asp), prevents the adhesiveness of cells of the marine amoeba Neoparamoeba aestuarina. In addition, elevated levels of GRGDSPK cause cells to alter their shapes from those with digitiform subpseudopodia to rounded cells with small lobed pseudopodia. These…
Cajal–Retzius and Subplate Cells
2013
The laminar and columnar organization of the mature cerebral cortex is determined by a variety of early developmental processes. Two distinct populations of early generated preplate neurons play key roles in corticogenesis. Cajal–Retzius neurons, located in the marginal zone (later layer I), control the formation of neocortical layers by releasing the extracellular matrix protein reelin, which serves as a guiding signal for migrating neurons. Subplate neurons in the lower neocortical layer play an active role in transient synaptic circuits and influence early cortical plasticity and the maturation of the columnar architecture. Both neuronal cell populations serve as transient synaptic targe…
Activity of Drug Efflux Transporters in Tumor Cells Under Hypoxic Conditions
2008
Tumor cells exhibit mechanisms by which chemotherapeutic drugs can be actively pumped out of the cell (e.g., p-glycoprotein pGP, MRP1), resulting in a multidrug resistant phenotype. Many human tumors show pronounced hypoxia which can result in a local ATP depletion which in turn may compromise the efficacy of these transporters. The aim of this study was therefore to assess the transport activity and expression of drug transporters under hypoxic conditions. Prostate carcinoma cells (R3327-AT1) were exposed to hypoxia (pO2≶0.5 mmHg) for up to 24h and pump activity was determined by an efflux assay. The results showed that exposing cells to hypoxia for 3–6 h led to a moderate increase in pGP …