High radiocesium levels in granite outcrop vegetation and reductions through time.

Levels of fallout radiocesium in vegetation were examined on three granite outcrops and a forested area in the Georgia piedmont during 1976-1980. Mean values averaged 4.3 times higher in three species collected on an outcrop than in the same species collected on clay soils in a nearby pine-hardwood forest. Levels in reindeer moss (Cladonia spp.) were significantly (p less than 0.01) lower in species that formed deep, entangled tufts with abundant, slender branches. Cesium levels decreased by as much as 90% from the mid-1960s but were virtually unchanged in the late 1970s. Dry-weight levels in mushrooms reached 18,470 Bq kg-1 (499.2 pCi g-1). Radiation levels in outcrop vegetation were higher than values found anywhere in the piedmont and were comparable to levels reported in plants from the sterile sandy soils of the temperate region coastal plains. These data fit well with earlier reported values and correlate well with the availability of atmospheric fallout. Outcrops can be used as sensitive environmental barometers for some contaminants.

Nematocidal principles in "oakmoss absolute" and nematocidal activity of 2,4-dihydroxybenzoates.

Nematocidal principles obtained from oakmoss absolute were identified as methyl 2,4-dihydroxy-3,6-di-methylbenzoate (2), ethyl 3-formyl-2,4-dihydroxy-6-methylbenzoate (4), and ethyl 5-chloro-3-formyl-2,4-dihydroxy-6-methylbenzoate (7). In relation to their structures, the nematocidal activity of 2,4-dihydroxybenzoates of methyl to tetradecyl was tested and the strongest activity was found in the octyl ester (minimal lethal concentration = 13 microM).

Propriedades biomédicas de las embriofitas asifonogamas andinas: II líquenes / Biomedical properties of the venezuelan andeans: lichenic species

Se reportan las propiedades biomédicas correspondientes a los líquenes de Los Andes venezolanos. Esta información es en su mayor parte nueva para la ciencia etnofarmacológica. de un total de 15 especies citadas, el 67.0// (10 sps.) se reportan sin antecedentes de uso en la literatura. El 86.6// (13 sps.) llevan usos biomédicos limitados sólo al área andina venezolana. El 26.6// (4 sps.) posee usos biomédicos de origen foráneo, mientras el 13.3// (2 sps.) lleva usos de origen mixto (autóctonos y alóctonos). Empleando criterios biomédicos modernos de eficiencia farmacológica, tenemos que el 86.6// (13 sps.) de los líquenes citados, son encontrados potencialmente eficaces. El 53.3// de las especies posee usos biomédicos que están correlacionados con los efectos atribuidos a sus principios activos. El resto revela, a partir del conocimiento de sus principios activos, importantes y variadas propiedades biomédicas, totalmente desconocidas dentro de las farmacopeas populares

Componentes químicos de la ramalina dictyota: dodge & Vareschi / Chemical compounds of the ramalina dictyota: dodge & Vareschi

De la Ramalina dictyota Dodge & Vareschi, fue aislado su único componente, que fue identificado con el ácido sekicaico

An EXAFS, and preliminary X-ray crystallographic, investigation of an iron-containing product from the lichen Cladonia deformis.

An iron-containing product in the acetone extract from the lichen Cladonia deformis has been investigated using chemical, spectroscopic and X-ray crystallographic methods. Visible-near UV, EPR and IR spectra indicate that the iron is present as high-spin Fe(III) and coordinates in an oxygen-containing environment arising from graciliformin (or graciliformin-like) ligands. This has been confirmed by an XAS (X-ray absorption) study using synchrotron radiation. Comparison of the EXAFS and XANES results with those obtained from a model, tris(pent-2,4-dionato)Fe(III), and detailed fitting using the single-scattering, curved-wave formalism for the EXAFS strongly supports the presence of a Fe(III) coordinated to five oxygen atoms from the graciliformin.

Characterization of biological ice nuclei from a lichen.

Biological ice nuclei (active at approximately -4 degrees C) were extracted from cells of the lichen Rhizoplaca chrysoleuca by sonication. Sensitivity to proteases, guanidine hydrochloride, and urea showed these nuclei to be proteinaceous. The nuclei were relatively heat stable, active from pH 1.5 to 12, and active without lipids, thereby demonstrating significant differences from bacterial ice nuclei.

Identification of lactose and D-volemitol in the lichen Sticta damaecornis

We now describe the identification, in the lichen Sticta damaecornis, of lactose, not previously found in lichens, and of D-volemitos which was unexpected taxonomically

Cs-137 concentration in reindeer and its fodder plants.

Radionuclides, especially the long-lived 137Cs (physical half-life 30 years), are accumulated efficiently in the northern, subarctic, lichen-reindeer-man foodchain. Until the Chernobyl accident the fallout nuclides studied originated from nuclear weapons tests. After this accident some fresh fallout was deposited in Finnish Lapland. Lichens grow very slowly and collect nutrients very efficiently from air, rain and snow. During winter the basic fodder plants for reindeer are lichens and some winter-green plants, shrubs and dry leaves. During the bare-ground season, the reindeer eat various grasses, herbs and leaves etc. Lichens constitute 30-50 per cent of the entire vegetable mass consumed by the reindeer in a year. The highest 137Cs-concentration 2500 Bq/kg dry weight was found in lichen in the middle of the 1960s. In 1985 the concentration had decreased to about 240 Bq/kg dry weight. After the Chernobyl accident the 137Cs-concentration in lichen varied from 200 to 2000 Bq/kg dry weight in Finnish Lapland. In reindeer fodder plant samples collected in the 1980s before the Chernobyl accident the 137Cs-concentration varied from 5 to 970 Bq/kg dry weight. The highest 137Cs-concentration in reindeer meat, about 2500 Bq/kg fresh weight, was found in 1965 and thereafter decreased to about 300 Bq/kg fresh weight in the winter before the Chernobyl accident. After the accident the mean 137Cs-concentration in reindeer meat from the 1986-87 slaughtering period was 720 Bq/kg fresh weight and in 1987-88, 630 Bq/kg fresh weight.

Background concentrations of lead and cadmium in the lichen Hypogymnia physodes at different altitudes.

The background concentrations of lead and cadmium in the epiphytic lichen Hypogymnia physodes were determined and found to depend on altitude. The lead content increases linearly with increasing altitude, whereas the cadmium content increases up to altitudes of 900-1100 m, and then decreases above this height.

A novel hemolysin from the lichen Parmelia pulla.

A hitherto unknown hemolysin from the lichen Parmelia pulla was discovered and a method was developed for its purification to apparent homogeneity. Saline phosphate buffer pH 7.2 extracted the bulk of the hemolysin from the lichen thalli. From this extract the hemolysin was purified by ammonium sulfate precipitation and gel filtration with Sepharose 6-B column. The overall recovery was about 75% and the purified hemolysin appeared to be electrophoretically homogenous and had a native molecular weight of 32,600. The purified hemolysin had a pH optimum around 5.5, stable at room temperature and gradually loses its activity upon freezing and thawing. Polyacrylamide gel electrophoresis of the purified hemolysin in the presence of sodium dodecyl sulfate revealed the presence of two types of subunits with apparent molecular weight of 18,000 and 14,000 respectively, indicating a dimeric (alpha beta) type of structure. Immunoblotting analysis demonstrated the presence of this hemolysin in crude extract prepared from P tinictina but not in crude extract from P tiliacea and P acetabulum. The purified hemolysin lyses rabbit erythrocytes and the rate of hemolysis was linear dependence on protein concentration. Erythrocytes obtained from various species including human were also lysed by the purified hemolysin in a concentration dependent manner.

Isoenzyme analysis of lichen algae in immobilized pH gradients.

A base for a modern species' concept of chlorococcal algae can be obtained not by morphological analysis, but by biochemical characters, e.g. isoenzyme banding patterns. From isolated lichen algae of the genus Trebouxia de Puymaly a set of five such enzymes has been studied by isoelectric focusing in immobilized pH gradients (IPG): phosphoglucomutase, phosphoglucose isomerase, malate dehydrogenase, mannitol dehydrogenase and leucine aminopeptidase. The first four are resolved into isoforms in a pH 4-7 IPG interval, while the last one is analyzed in an IPG pH 3.5-5 span. The patterns are specific for distinct populations, inter- and intraspecifically varying in dependence from their geographical distribution or the lichen species from which they have been isolated. Their limited heterogeneity (one to four isoforms) suggests that they are the products of specific genes rather than artefacts of the extraction procedure or the IPG analysis. Sharp isozyme patterns can only be obtained in a mixed-bed, carrier-ampholyte (CA)-IPG gel and by anodic application, suggesting that the recently proposed mechanism of hydrophobic protein-IPG matrix interaction (Electrophoresis, 1987, 8, 62-70) is fully operative here. As an additional mechanism, it is proposed that, in some cases, CA might simply act, when added to an IPG gel, by buffering, in the transient state, the sample zone before the protein migrates from the liquid phase into the IPG matrix.

Membrane-bound Ca2+ distribution visualized by chlorotetracycline fluorescence during morphogenesis of soredia in a lichen.

In the lichen Parmelia caperata (L.) Ach. the distribution pattern of membrane-bound Ca2+ is investigated in the symbionts by chlorotetracycline (CTC)-induced fluorescence during the development of propagative structures, the soredia. The results demonstrate that Ca2+ accumulation in the alga and the fungus is associated with this morphogenetic process; particularly, polarized hyphal growth involves a tip-to-base Ca2+ gradient. CTC fluorescence distribution is coincident with that of cholinesterase (ChE) activity during morphogenesis of soredia. A comparison is suggested with 'embryonic ChE' of animal cells, where developmental events are regulated by a cholinergic mechanism that also modulates Ca2+ levels.

Metal amounts in the lichen Ramalina duriaei (De Not.) Bagl. transplanted at biomonitoring sites around a new coal-fired power station after 1 year of operation.

The lichen Ramalina duriaei (De Not.) Bagl. was transplanted to 22 biomonitoring sites for 1 year (1981-1982). The amounts of Ni, Cr, Cu, Zn, Pb, Mn, and Fe in the lichen material were measured at the end of the transplantation period and the data were compared with the amounts of five of these metals (Ni, Cr, Cu, Zn, and Pb) which were detected in the same lichen species transplanted in the same study area during the 1979-1980 period. The differences between the amounts of the five metals detected during the two periods are discussed. The increase in amounts of some of the metals in the 1981-1982 lichen material (Pb, Ni, and probably Cr) reflects the increase in the total number of motor vehicles between the two periods within the study area. The decrease of Zn in the lichen after the second period reflects a decrease in the use of Zn as a constituent of foliar nutrients in agriculture used for crop spraying. The increase of Cr and Ni in the transplanted lichen after the 1981-1982 period probably also reflects, apart from vehicle pollution, a certain emission from the 250-m-high stacks of a new coal-fired electricity-generating power station.

Bioindication: a short review on the use of plants as indicators of heavy metals.

This paper discusses some fundamental principles of bioindication. The presentation follows a classification of methods based on the different levels of organization implied in the various approaches. Special references are made to plants that accumulate heavy metals.

Uptake of natural and man-made radionuclides by lichens and mushrooms.

Due to the large absorbing surface of the mycelium that grows in the upper parts of the soil mushrooms take up higher amounts of 137Cs and 40K than lichens. Besides these nuclides only the long-lived radionuclides 125Sb and 60Co could be measured; but not the short-lived fission-products 144Ce, 95Zr and 95Nb which probably decayed before absorption into the mycelium. These nuclides, however, are present in lichens because of their surface structures which enable high foliar deposition. The 137Cs-content of lichens is probably due to absorption by the mycobiont and seems to be used to satisfy their potassium-requirements. Mushrooms on the other hand are characterized by a relatively stable potassium-content and a wide ranging 137Cs-content which depends on the availability in different substrates. Occasionally the natural radionuclides 238U and 226Ra could be detected in mushroom and lichen samples, showing no correlation with the natural radionuclide content of the soil.