Search results for "AMALi"
showing 10 items of 25 documents
Brief an Garlieb H. Merkel
1799
Ms. 930a, Nr. 8, Bl. 22r-23v Böttiger, Karl August. Brief an Garlieb H. Merkel, Weimar, d[en] 13. November 1797 Autora rokraksts / Autograph, vācu, angļu un latīņu val. / Deutsch, Englisch und Latein [4] lpp. / S. Attēlu numuri / Bildnummern: 930a-008-1 – 930a-008-4 Der Verfasser nennt in diesem inhaltsreichen Brief zahlreiche Namen und hält nicht nur die Verbindung mit Merkel, die aus dessen erstem Aufenthalt in Weimar resultierte, aufrecht, sondern gibt ihm weitere Hinweise und Empfehlung für seinen weiteren Aufenthalt in Dänemark. So rät er zur Übersetzung dreier Romane aus dem Englischen, darunter Jane Wests „A gossip's story“ (London 1796). Ferner bittet der Verfasser Merkel um Gefälli…
Releasing rates of inorganic ions in lichens monitored by capillary zone electrophoresis as indicators of atmospheric pollution
2000
Abstract The releasing rates of inorganic ions in lichens when a thallus sample is sonicated under water, were studied. Ramalina farinacea samples taken from two locations exposed to atmospheric pollution sources at Els Ports (Castellon, Spain), and from three control locations, were used. Samples without visual symptoms of injuries were sonicated from 3 to 6 successive 10-min periods while renewing the water layer in between. Experiments with successive 2-min-sonication periods were also performed. The extracts were analysed by capillary zone electrophoresis, and K + , NH 4 + , Na + , Ca 2+ , Mg 2+ , Cl − , SO 4 2− and NO 3 − were detected. The apparently undamaged lichens sampled at locat…
INDAGINI CHEMIOTASSONOMICHE PRELIMINARI SU ROCCELLA DC. SP. PL. E RAMALINA FARINACEA (L.) ACH. MEDIANTE IDENTIFICAZIONE DELLE SOSTANZE LICHENICHE.
2007
In questo studio, sono stati presi in considerazione specie plurime appartenenti al genere Roccella DC. e la specie Ramalina farinacea (L.) Ach., sui quali sono state svolte indagini chemiotassonomiche mediante l’identificazione di sostanze licheniche. Il presente lavoro, utilizza tre metodologie chimiche, per la ricerca di metabolici secondari presenti. Negli ultimi trent’anni sono stati effettuati in molte parti del mondo studi sulle sostanze licheniche, Culberson negli Usa, Huneck in Germania, Yoshimura in Giappone, Elix in Australia. In Italia questo tipo di ricerca è stata portata avanti In questo contesto si colloca lo studio qui proposto, avendo come fine il riconoscimento dei metabo…
Oxidative stress induces distinct physiological responses in the two Trebouxia phycobionts of the lichen Ramalina farinacea
2010
† Background and Aims Most lichens form associations with Trebouxia phycobionts and some of them simultaneously include genetically different algal lineages. In other symbiotic systems involving algae (e.g. reef corals), the relative abundances of different endosymbiotic algal clades may change over time. This process seems to provide a mechanism allowing the organism to respond to environmental stress. A similar mechanism may operate in lichens with more than one algal lineage, likewise protecting them against environmental stresses. Here, the physiological responses to oxidative stress of two distinct Trebouxia phycobionts (provisionally named TR1 and TR9) that coexist within the lichen R…
The organic air pollutant cumene hydroperoxide interferes with NOantioxidant role in rehydrating lichen
2013
Organic pollutants effects on lichens have not been addressed. Rehydration is critical for lichens, a burst of free radicals involving NO occurs. Repeated dehydrations with organic pollutants could increase oxidative damage. Our aim is to learn the effects of cumene hydroperoxide (CP) during lichen rehydration using Ramalina farinacea (L.) Ach., its photobiont Trebouxia spp. and Asterochloris erici. Confocal imaging shows intracellular ROS and NO production within myco and phycobionts, being the chloroplast the main source of free radicals. CP increases ROS, NO and lipid peroxidation and reduces chlorophyll autofluorescence, although photosynthesis remains unaffected. Concomitant NO inhibit…
Different strategies to achieve Pb-tolerance by the two Trebouxia algae coexisting in the lichen Ramalina farinacea.
2012
Lichen thalli are permeable to airborne substances, including heavy metals, which are harmful to cell metabolism. Ramalina farinacea shows a moderate tolerance to Pb. This lichen comprises two Trebouxia phycobionts, provisionally referred to as TR1 and TR9, with distinct physiological responses to acute oxidative stress. Thus, there is a more severe decay in photosynthesis and photosynthetic pigments in TR1 than in TR9. Similarly, under oxidative stress, antioxidant enzymes and HSP70 protein decrease in TR1 but increase in TR9. Since Pb toxicity is associated with increased ROS formation, we hypothesized greater Pb tolerance in this phycobiont. Accordingly, the aim of the present study was …
The genetic structure of the cosmopolitan three-partner lichenRamalina farinaceaevidences the concerted diversification of symbionts
2012
The epiphytic lichen Ramalina farinacea is distributed throughout the northern hemisphere in which the same two algal Trebouxia species (provisionally named TR1 and TR9) coexist in every thallus. Ramalina farinacea symbionts were characterized based on the two fungal nuclear loci (nrITS and rpb2 ) along with the primary and secondary structures of nrITS from each Trebouxia species in the Iberian Peninsula and Canary Islands. The results indicated a noticeable genetic differentiation between mycobionts from these two geographic areas and also suggested concerted changes in the three partners of a lichen symbiosis toward two clearly distinguishable ‘holobiont’ lineages. Modeling of ITS2 RNA s…
Differences in the cell walls and extracellular polymers of the two Trebouxia microalgae coexisting in the lichen Ramalina farinacea are consistent w…
2015
Trebouxia TR1 and T. TR9 are the two microalgae that coexist within Ramalina farinacea thalli. In the presence of Pb, TR9 formed extracellular aggregates, while TR1 showed a lower wall lead retention capability. Herein, we studied the cell walls and extracellular polymers (EPS) of TR1 and TR9, and their possible implication in the different Pb retention capacity of these microalgae. The proportion of cell walls on the overall cell biomass was 2.6 times higher in TR9 than in TR1. Glycosyl linkage analysis indicated the presence of hot-water soluble β-galactofuranan(s) in both cell walls, distinct from that previously described in Asterochloris, with increased rhamnose content in TR9 and a hi…
Two Trebouxia algae with different physiological performances are ever-present in lichen thalli of Ramalina farinacea. Coexistence versus Competition?
2010
This study was funded by the Spanish Ministry of Education and Science (CGL2006-12917-C02-01/02), the Spanish Ministry of Science and Innovation (CGL2009-13429-C02-01/02), the AECID (PCI_A/024755/09) and the Generalitat Valenciana (PROMETEO 174/2008 GVA). We are grateful to Dr J. Gimeno-Romeu (University of California, Davis, USA) and to Dr P. J. G. de Nova (IREC, Ciudad Real, Spain), who were the first to isolate DNA from Ramalina farinacea thalli in our group. Wendy Ran revised the manuscript in English.
Bacterial communities associated with the lichen Ramalina farinacea (L.) Ach.: composition, biodiversity and biotechnological potential
2017
Los líquenes son un ejemplo clásico de asociación simbiótica autosuficiente, compuesta por, al menos, un hongo filamentoso (micobionte, heterótrofo) y cianobacterias y/o algas verdes unicelulares (fotobiontes, fotosintéticos). Se desarrollan gracias a la combinación adecuada de hongos y algas y/o cianobacterias, y sus talos son los fenotipos resultantes (holobiontes). Dicha asociación les permite colonizar y crecer en ambientes diversos y extremos que no podrían habitar los simbiontes de forma independiente. Estudios recientes, mediante aproximaciones ómicas, han revelado la gran abundancia y diversidad de las comunidades bacterianas asociadas a los líquenes. Estos estudios han cambiado la …