Levantilides A and B, 20-membered macrolides from a Micromonospora strain isolated from the Mediterranean deep sea sediment     

Gärtner A  Ohlendorf B  Schulz D  Zinecker H  Wiese J  Imhoff JF 《Marine drugs》2011,9(1):98-108

Two new 20-membered macrolides, levantilide A and B, were isolated from the Micromonospora strain M71-A77. Strain M71-A77 was recovered from an Eastern Mediterranean deep-sea sediment sample and revealed to produce the levantilides under in situ salinity of 38.6 ‰. The chemical structures of the levantilides were elucidated on the basis of different one- and two- dimensional NMR experiments. Levantilide A exhibits a moderate antiproliferative activity against several tumor cell lines.  相似文献   

Phosphorus pools in soil after land conversion from silvopasture to arable and grassland use          下载免费PDF全文

Anna Slazak  Dirk Freese  Eduardo S. Matos  Seth Nii‐Annang  Reinhard F. Hüttl 《植物养料与土壤学杂志》2014,177(2):159-167

Differences in soil P among silvopasture, grassland, and arable lands have been well established. Nevertheless, most of the reports compare soil properties under long‐term sites. Thus, there exists little information on the effect of the conversion of silvopasture to arable or grassland use on soil P pools. The objective of the study was to determine the impact of converting silvopasture system (SP) into arable cropping and grassland system on the distribution of P pools and potential P bioavailability. We compared the following systems: SP system, SP converted to arable cropland (SP‐AL), SP converted to grassland (SP‐GL), and for comparative purposes, a long‐term arable cropland (AL). The P fractionation was performed by a sequential extraction scheme, using acid and alkaline extractants on samples collected from the 0–10 and 10–20 cm soil layers. It was assumed that the large variations in soil‐P fractionations are caused by the different management practices associated with land conversion. The results of P fractionation showed a dominance of calcium‐bound P, HCl‐extractable Pi constituted up to 36% of the soil total P (TP). However, the type of land use did not affect this P fraction. On the other hand, the reduction in labile‐P_i and NaOH‐P_i fractions observed at the SP‐AL site may have led to the decline in readily available P. The soil total organic P (TP_o) content was 8% and 17% lower at SP‐AL compared to SP and SP‐GL site, respectively. Labile organic‐P (labile‐P_o) content was markedly higher at SP site compared to arable soils, and was ≈ 10% of TP_o. The NaOH‐P_o constituted the highest fraction of the organic‐P pool (55%–79% of TP_o) across all the study systems, and was positively correlated with TP_o (p < 0.01). The study indicates that conversion of SP system in temperate regions to arable cropping with conventional tillage seems to result in the reduction of P availability compared to SP, indicating SP as an important land‐use practice.  相似文献   

Designing protected areas to conserve riverine biodiversity: Lessons from a hypothetical redesign of the Kruger National Park     

Dirk J. Roux  Jeanne L. Nel 《Biological conservation》2008,141(1):100-117

The process of designing protected areas to represent all ecosystems in an area adequately is becoming increasingly sophisticated. To date freshwater aquatic ecosystems have seldom been considered in this process. How much of a difference does it make when they are considered as well?This study examined the conservation of riverine biodiversity within 17 assessment units contained by the catchment areas of five perennial rivers flowing through Kruger National Park and two seasonal rivers that are largely contained within this park. Physical river types, fish species and invertebrate families or genera were used as surrogates of riverine biodiversity. Conservation planning software was used to select an optimal set of planning units to represent and maintain riverine biodiversity.The current spatial configuration of Kruger National Park, largely an accident of history, is particularly poor when assessed against the objective of conserving riverine biodiversity. Several alternative layouts are examined. These options are theoretical since there is little current opportunity to reassign land uses in the region. This study shows that substantially improved layouts for both riverine and terrestrial biodiversity are possible, under the constraint of the same total area under protection. The study also shows that even these optimal layouts are only partially successful in efforts to conserve fully representative samples of riverine biodiversity. Because of the longitudinal connectivity of rivers, conservation strategies that extend beyond protected areas are essential. Explicit conservation visions, targets and strategies need to be included in integrated water resource management plans.Based on the results of this study, nine recommendations are provided for increasing the effectiveness of current and future protected areas in conserving riverine biodiversity. These are to use systematic conservation planning to make biodiversity benefits explicit; mend the disconnect between terrestrial and freshwater conservation; use multiple surrogates wherever possible; be strategic about the collection and management of primary data; strive for maximum hydrologic connectivity; resist development pressure; foster good relationships across park fences; where relevant, pursue multi-national cooperation at the basin scale; and engage the value debate and resolve awareness and capacity constraints.  相似文献   

Chemical composition of vintage preban absinthe with special reference to thujone, fenchone, pinocamphone, methanol, copper, and antimony concentrations     

Lachenmeier DW  Nathan-Maister D  Breaux TA  Sohnius EM  Schoeberl K  Kuballa T 《Journal of agricultural and food chemistry》2008,56(9):3073-3081

Thirteen samples of authentic absinthe dating from the preban era (i.e., prior to 1915) were analyzed for parameters that were hypothesized as contributing to the toxicity of the spirit, including naturally occurring herbal essences (thujone, pinocamphone, fenchone), methanol, higher alcohols, copper, and antimony. The total thujone content of preban absinthe was found to range between 0.5 and 48.3 mg/L, with an average concentration of 25.4 +/- 20.3 mg/L and a median concentration of 33.3 mg/L. The authors conclude that the thujone concentration of preban absinthe was generally overestimated in the past. The analysis of postban (1915-1988) and modern commercial absinthes (2003-2006) showed that the encompassed thujone ranges of all absinthes are quite similar, disproving the supposition that a fundamental difference exists between preban and modern absinthes manufactured according to historical recipes. Analyses of pinocamphone, fenchone, base spirits, copper, and antimony were inconspicuous. All things considered, nothing besides ethanol was found in the absinthes that was able to explain the syndrome "absinthism".  相似文献