Semisynthesis and pharmacological investigation of lipo-alkaloids prepared from aconitine

Processed aconite drugs are widely used in Eastern medicine as painkillers and antirheumatic agents. It is known that the traditional processing of aconite drugs increases the amount of lipo-alkaloids. In order to obtain information about the pharmacological potential of these compounds, semisynthesis of 9 aconitine-derived lipo-alkaloids was carried out and their COX-1, COX-2 and LTB₄ formation inhibitory activities were investigated. It was found that compounds esterified with unsaturated fatty acids demonstrated significant COX-2 inhibitory effects, while in the COX-1 assay only 14-benzoylaconine-8-O-eicosapentaenoate exerted remarkable activity. The inhibition of LTB₄ formation was pronounced in cases of long chain fatty acid derivatives.     

Quantifying successional rates in western aspen woodlands: Current conditions,future predictions

Stands of quaking aspen (Populus tremuloides) rank among the most biologically diverse plant communities across the intermountain region of western North America. Marked declines of aspen have occurred in recent decades, likely due to a combination of effects from changes in fire regimes, herbivory, climate (e.g. drought), and interspecific competition with conifer species. However, it is poorly understood how the effects of these factors are manifested at a landscape scale over decadal time periods. Analysis of field data combined with topographic information collected across the 500,000 ha Owyhee Plateau in southwestern Idaho revealed that aspen in the area occur in three different biophysical settings; First, aspen stands exist at high altitudes on south-facing slopes where local conifer species are not likely to occur because of limiting temperature or precipitation levels under current climate conditions. In these areas aspen is the potential vegetation type rather than conifers. Second, aspen grow on anomalously wet microsites (e.g. near springs), and third, aspen grow within upland mixed aspen/conifer stands, which are experiencing rapid rates of conifer establishment. Based on a paired t-test (α = 0.05) we conclude that stands growing on wet microsites show significantly slower successional rates of conifer establishment relative to upland aspen stands. We developed a conceptual state-and-transition model for upland aspen/conifer stands occurring across a range of topographic positions. We then parameterized the model using extensive field data in the vegetation dynamics computer simulation model Vegetation Dynamics Development Tool (VDDT), and examined the current and future aspen distribution under varying fire regimes. Model results indicate that average fire return intervals of 50–70 years are desirable for maintenance of aspen in upland areas where conifers are present. Under the current fire regime in the area many upland aspen/conifer stands will likely be lost within 80–200 years. Thresholds for the effect of conifer encroachment and browsing on aspen regeneration identified through this research are similar to those described by others across the West. We therefore suggest that the results presented for the Owyhee Plateau are likely applicable to semi-arid aspen woodlands across the American West where succession to conifers is a cause of aspen decline.     

Vertical variations in wood basic density for two softwood species

European Journal of Forest Research - Studies on wood basic density (BD) vertical variations become essential to predict more accurately the within-stem distributions of biomass and wood quality in...     

Evaluating agroforestry interventions in extension projects

Because of the relative dearth of scientific information in agroforestry, monitoring and evaluation of agroforestry technologies in development projects plays an important role in the development and improvement of technical extension recommendations. To identify appropriate methodologies, ICRAF conducted in 1988–89 a review of agroforestry technology monitoring and evaluation in 166 projects worldwide, of which 108 responded. Almost 80% of these were involved in technology evaluation. Many extension projects were conducting research to test technologies on-farm or on research plots. Technology evaluation by projects focused on the biological of trees, often with inadequate consideration of the technology context. Few projects seemed to use farmer assessment in evaluation. Recommendations are made for an effective evaluation process and selection of appropriate methods and variables to be assessed by projects. Methods should be selected according to the availability of resources and should favour collaborative or collegial interaction between farmers and project staff.     

Evaluation of the flammability of gorse (<Emphasis Type="Italic">Ulex europaeus</Emphasis> L.) managed by prescribed burning

• Introduction  

The abandonment of rural areas has led to an increase of the fire-prone European gorse (Ulex europaeus L.) communities in some regions, where prescribed burning is a technique applied to control them. Understanding flammability changes after treatments is crucial for the sustainable use of fire.     

Induction of heme oxygenase-1 by Macleaya cordata extract and its constituent sanguinarine in RAW264.7 cells

Macleaya cordata (plume poppy) is used in traditional Chinese medicine for its anti-inflammatory and antibacterial activities. In this study, we examined whether M. cordata extract and/or its major alkaloid constituents, protopine, allocryptopine, sanguinarine and chelerythrine activate the Nrf2 signalling pathway which regulates the expression of cytoprotective enzymes including heme oxygenase-1 (HO-1) and thioredoxin 1. In murine macrophage RAW264.7 cells, M. cordata extract increased both mRNA and protein levels of HO-1. Of the alkaloids examined, only sanguinarine appeared to be responsible for these effects. At the concentration of 2 μM, sanguinarine induced nuclear accumulation of Nrf2, increased the expression of Hmox1 gene encoding HO-1 and elevated HO-1 protein levels. Sanguinarine-induced Hmox1 mRNA expression was suppressed by SB203580, a pharmacologic inhibitor of p38 mitogen-activated protein kinases (p38 MAPKs). The upregulation of HO-1 in RAW264.7 cells by sanguinarine was, however, accompanied by decrease in cell viability. Nonetheless, sanguinarine at micromolar, non-cytotoxic concentrations elevated protein levels of HO-1 and thioredoxin 1 in primary cultures of human hepatocytes. We conclude that sanguinarine may, under appropriate conditions, increase the capacity of the enzymatic antioxidant defence system via activation of the p38 MAPK/Nrf2 pathway.     

Estimation of stem attributes using a combination of terrestrial and airborne laser scanning

Properties of individual trees can be estimated from airborne laser scanning (ALS) data provided that the scanning is dense enough and the positions of field-measured trees are available as training data. However, such detailed manual field measurements are laborious. This paper presents new methods to use terrestrial laser scanning (TLS) for automatic measurements of tree stems and to further link these ground measurements to ALS data analyzed at the single tree level. The methods have been validated in six 80 × 80 m field plots in spruce-dominated forest (lat. 58°N, long. 13°E). In a first step, individual tree stems were automatically detected from TLS data. The root mean square error (RMSE) for DBH was 38.0 mm (13.1 %), and the bias was 1.6 mm (0.5 %). In a second step, trees detected from the TLS data were automatically co-registered and linked with the corresponding trees detected from the ALS data. In a third step, tree level regression models were created for stem attributes derived from the TLS data using independent variables derived from trees detected from the ALS data. Leave-one-out cross-validation for one field plot at a time provided an RMSE for tree level ALS estimates trained with TLS data of 46.0 mm (15.4 %) for DBH, 9.4 dm (3.7 %) for tree height, and 197.4 dm³ (34.0 %) for stem volume, which was nearly as accurate as when data from manual field inventory were used for training.     

Effects of the needle bladder rust (Chrysomyxa rhododendri) on Norway spruce: implications for subalpine forests

Norway spruce trees in the subalpine forests of the European Alps are frequently attacked by the needle rust Chrysomyxa rhododendri. The obligate parasite undergoes a complex life cycle with a host shift between rhododendrons (Rhododendron sp.) and Norway spruce [Picea abies (L.) Karsten] and causes a yellowing and defoliation of the current-year needles in summer. Infected trees show several anatomical, morphological and physiological modifications, including a decrease in pigment content and net photosynthesis of infected needles, lower biomass production and reduced radial and height growth. The consequences are diminished timber yield and cripple growth. Because of repeated heavy infections in recent years, forest managers report increasing difficulties in both natural regeneration and afforestation at high elevation sites, where rhododendrons occur. This review gives a summary of the present knowledge about the effects of C. rhododendri infections on Norway spruce, including so far unpublished findings and with particular attention to the phenomena of resistant trees. Implications for subalpine forests and counter strategies are discussed.     

Occupational health survey of farm workers by camp health aides

Little is known about the magnitude of occupational health problems among migrant farm workers. A community-based cross-sectional survey was conducted in two migrant farm worker communities: Homestead, Florida, and Kankakee, Illinois. Camp Health Aides (CHAs) interviewed 425 workers about job tasks, personal protective equipment (PPE), field sanitation, work exposures, and selected health conditions. Limited provision of personal protective equipment was reported among those reporting early re-entry tasks: 35% in Kankakee and 42% in Homestead were provided gloves, and 22% in Homestead and 0% in Kankakee were provided protective clothing. About two-thirds were provided toilet facilities and water for hand-washing. Workers reported high prevalences of health conditions consistent with exposure to ergonomic hazards and pesticides. The prevalence of back pain in the past 12 months was 39% in Homestead and 24% in Kankakee. Among Homestead participants, 35% experienced eye symptoms, while 31% reported skin symptoms. These symptoms were less prevalent among Kankakee participants (16% for both eye and skin symptoms). Specific areas of concern included back pain associated with heavy lifting and ladder work; eye and skin irritation associated with fertilizer application tasks and with working in fields during or after spraying of chemicals, especially early re-entry of sprayed fields; and skin irritation associated with a lack of access to hand-washing facilities. In both Kankakee and Homestead, better adherence to safety standards is needed, as well as greater efforts to implement solutions that are available to help prevent work-related musculoskeletal problems.     

A method of preparing mesocosms for assessing complex biotic processes in soils

Equipment and handling methods for the preparation of soil mesocosms were developed. The mesocosms were used to investigate the interrelationships between mesofauna and microflora in a coniferous forest soil. Soil monoliths were taken from the ground, defaunated by deep-freezing, wrapped in nets to control reimmigration of different faunal size-classes, and replanted in the field for 8 months. in a practical test the technique described here proved to be an inexpensive field method for producing a replicated series of mesocosm in a short time. Deep-freezing is appropriate for defaunating soil monoliths. The fine nets effectively exluded meso-and macrofauna. No significant differences were found in the abundance of Enchytraeids and Collembola between recolonized mesocosms and the undisturbed control at the end of the study period. In contrast, oribatid mite abundace was still greatly reduced in the recolonized esocosms. Dominance structure and species composition of the more dominant oribatid species in the different treatments were apparently similar. To compensate for the low colonization ability of oribatids, a reintroduction of selected animal size-classes to defaunated monoliths is recommended.