Field evaluation of antisense RNA mediated inhibition of GBSS gene expression in potato

Summary Granule-bound starch synthase (GBSS) catalyses the synthesis of amylose in starch granules. Analysis of antisense RNA mediated inhibition of GBSS gene expression in large numbers of tubers from in vitro grown, greenhouse grown and field grown transgenic potato plants revealed stable and total inhibition of GBSS gene expression in one clone. In three other transgenic genotypes partial and unstable inhibition was found. In these genotypes both GBSS activity and amylose content were remarkably reduced compared with the non-transformed control genotype. No relationship was found between the level of inhibition of GBSS gene expression and yield and dry matter content.     

Impact of lakeshore development on green frog abundance

Many amphibian species exhibit metapopulation spatial dynamics and temporally are faced with local population extinction and re-colonization. These natural population fluctuations can exhibit stochastic effects when human-caused alteration and fragmentation of habitats occur during sensitive life-cycle events. In this study, we explored the effects of shoreline development on adult green frogs Rana clamitans melanota on lakes (n=24) of northern Wisconsin. We estimated green frog abundance using both auditory and direct observation surveys. The immediate shoreline habitat was mapped and placed into a Geographical Information System (GIS) for analysis. Adult green frog populations were significantly lower on lakes with varying degrees of shoreline house and cottage development than lakes with little or no development. A negative linear relationship existed between shoreline development densities and the number of adult green frogs. However, house and cottage densities alone did not directly explain this reduction. Analysis of variance (ANOVA) identified that the amount of suitable habitat, not development density, significantly affected green frog abundance. Therefore, greater development densities significantly decrease breeding habitat quality, resulting in lower adult frog abundance. These and other findings suggest that lakeshore development regulations are not protecting sensitive amphibian species.     

Orographic enhancement of wet deposition in the United Kingdom: Continuous monitoring

Continuous monitoring of cloud and rain samples at three mountain sites in the UK has allowed consideration of the long term impact of the enhancement of the wet deposition of pollutants by orographie effects, specifically the scavenging of cap cloud droplets by rain falling from above (the seeder-feeder effects). The concentration of the major pollutant ions in the cloud water is related to the relative proximity of each site to marine and anthropogenic sources of aerosol. In general, the concentrations of major ions in precipitation at summit sites exceed those in precipitation to low ground nearby by 20% to 50%. Concentrations in orographie cloud exceed those in upwind rain by between a factor of five and ten. The results are consistent with seeder-feeder scavenging of hill cloud by falling precipitation in which the average concentration of ions in scavenged hill cloud exceed those in precipitation upwind by a factor of 1.7 to 2.3 for sulphate and nitrate respectively at Dunslair Heights and 1.5 to 1.8 for sulphate and nitrate at Holme Moss. The results suggest that the parameterisation of this relationship with scavenged feeder cloud water concentrations assumed to exceed those in seeder rain by a factor of two for the production of predictive maps of wet deposition in mountainous regions of the U.K. is satisfactory.     

Numerical taxonomic studies in the generaTriticum L. andPisum L.

Summary Up till now numerical taxonomy has been applied to cultivated plants only to a limited extent though this method seems to be especially suitable for handling the great diversity of these plants. Moreover the theory of numerical taxonomy has not been studied sufficiently.Therefore studies with cultivated plants were begun with the aim to investigate the fitness of different numerical taxonomic techniques for their classification. Materials used: 1) 24 species ofTriticum and additionally 24 species ofAegilops 2) 1225Triticum taxa from Iran (mostlyT. aestivum) 3) 312 taxa ofPisum (mostlyP. sativum).Using 10 coefficients and 7 clustering methods inTriticum andAegilops in most cases a clear separation of both genera resulted as well as a species arrangement withinTriticum according to the genomes.The main aim when dealing with the wheat from Iran was the investigation of the influence of different character sets. At this the coefficient ofGower and the unweighted pair-group method using arithmetic averages (UPGMA) were applied. The separation of the different species is satisfying clear while the representatives of the different varieties ofT. aestivum could not always be found in one cluster. This effect increased when adding further characters sets.InPisum the influence of 11 similarity coefficients to the dendrogram formation has been investigated. With two-state characters the simple matching coefficient and with mainly multistate characters the Canberra metric gave best results (using UPGMA and information measures SUMRAT and SAMRAT).The hitherto existing results show the complicatedness of the evaluation of numerical taxonomic methods in their application to cultivated plants. Therefore generalizations are not yet possible.

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Numerisch-taxonomische Studien in den GattungenTriticum L. undPisum L.

     

Pre-extraction preparation (fresh, frozen, freeze-dried, or acetone powdered) and long-term storage of fruit and vegetable tissues: effects on antioxidant enzyme activity

Activities of the antioxidant enzymes ascorbate peroxidase, catalase, dehydroascorbate reductase, glutathione reductase, guaiacol peroxidase, monodehydroascorbate reductase, and superoxide dismutase were assayed in honeydew (Cucumis melo L.) fruit and spinach (Spinacia oleracea L.) leaves either as fresh, frozen to -80 degrees C, frozen in liquid nitrogen, freeze-dried, or acetone powder, representing the various ways tissues are treated prior to enzyme extraction. Treated tissues were analyzed following treatment or stored for up to 8 weeks at -80 degrees C. Enzyme activities in fruit frozen with or without liquid nitrogen and leaves frozen with or without liquid nitrogen or freeze-dried were equal to those of fresh tissue. Enzyme activities in freeze-dried or acetone-powdered fruit and leaves and in acetone-powdered tissues were significantly higher or lower than those in fresh tissue. Enzyme activities in both tissues frozen with or without liquid nitrogen and stored for 8 weeks at -80 degrees C changed little; those in freeze-dried and acetone-powdered tissues, however, significantly increased/decreased over the same period. Fresh tissue should be used in antioxidant enzyme assays, but if storage is necessary, tissues should be placed directly into a -80 degrees C freezer.     

Ergosterol and microbial biomass relationship in soil

Ergosterol and microbial biomass C were measured in 26 arable, 16 grassland and 30 forest soils. The ergosterol content ranged from 0.75 to 12.94 g g^-1 soil. The geometric mean ergosterol content of grassland and forest soils was around 5.5 g g^-1, that of the arable soils 2.14 g g^-1. The ergosterol was significantly correlated with biomass C in the entire group of soils, but not in the subgroups of grassland and forest soils. The geometric mean of the ergosterol: microbial biomass C ratio was 6.0 mg g^-1, increasing in the order grassland (5.1), arable land (5.4) and woodland (7.2). The ergosterol:microbial biomass C ratio had a strong negative relationship with the decreasing cation exchange capacity and soil pH, indicating that the fungal part of the total microbial biomass in soils increased when the buffer capacity decreased. The average ergosterol concentration calculated from literature data was 5.1 mg g^-1 fungal dry weight. Assuming that fungi contain 46% C, the conversion factor from micrograms ergosterol to micrograms fungal biomass C is 90. For soil samples, neither saponification of the extract nor the more effective direct saponification during extraction seems to be really necessary.     

Wasseraufnahme und Wasserverbrauch von Ackerbohne und Hafer auf einer Löß-Parabraunerde

Water uptake and water use of field beans and oats grown on a loess-derived grey-brown podzolic soil (Eutroboralf) The terms of the water-balance equation were determined, when field beans (Vicia faba L.) and oats (Avena sativa L.) were grown on a loess-derived soil during two seasons (1982 and 1983). A specific objective of this investigation was to quantify the water uptake from different layers and the total transpiration of both crops, as field beans are known to be susceptible to water shortage. Beside soil physical measurements climatological data for calculation of potential evapotranspiration were recorded. Plants were analyzed due to leaf area and root length density once a week. Actual evapotranspiration including interception, as determined by the soil physical approach, was split up by calculation procedures into actual evaporation, interception and actual transpiration. Total root length and root length density of field beans were much smaller and the rooting system was shallower as compared with oats. Development of leaf area and of roots was slower with beans than oats and was retarted by 2 to 3 weeks. Accordingly the time of maximum transpiration was found begin of June with oats and at begin of July with field beans. Despite reduced root growth Vicia faba transpired 250 mm in total, that is 86 % of what was found for the cereal crop (290 mm). Water uptake field beans however, was restricted to the upper 80-cm profile with 90 % of total uptake. The water uptake per unit length of root was substantial higher with beans than with oats. Due to the delayed development of the bean crop the losses by evaporation and seepage exceeded those from the soil grown to oats by 40mm (64 %). These investigations support the conclusion that yield stability of field beans may be substantially improved by selection of new varieties with increased rooting depth.     

Occurrence of zearalenone-4-beta-D-glucopyranoside in wheat

An LC-MS method was developed for the analysis of zearalenone-4-beta-D-glucopyranoside and zearalenone in wheat (Triticum aestivum). The limit of determination for zearalenone-4-beta-D-glucopyranoside and zearalenone was 10 microg/kg. The recovery rates were calculated to be 69% and 89% at a concentration of 100 microg/kg for zearalenone-4-beta-D-glucopyranoside and zearalenone, respectively. Twenty-four Bavarian wheat samples from a 1999 harvest were analyzed. Zearalenone was present in 22 of 24 field samples, the levels ranged from 11 to 860 microg/kg. Zearalenone-4-beta-D-glucopyranoside was found in 10 of the zearalenone positive samples (42%) at levels ranging from 17 to 104 microg/kg. The amounts of zearalenone-4-beta-D-glucopyranoside were correlated to those of zearalenone (r2 = 0.86, b = 0.10). After gastrointestinal hydrolyzation, zearalenone-4-beta-glucopyranoside might be implicated in the development of a zearalenone-syndrome. Therefore, more attention should be focused on conjugated mycotoxins in food and feed.     

Interlinked fast and slow positive feedback loops drive reliable cell decisions

Positive feedback is a ubiquitous signal transduction motif that allows systems to convert graded inputs into decisive, all-or-none outputs. Here we investigate why the positive feedback switches that regulate polarization of budding yeast, calcium signaling, Xenopus oocyte maturation, and various other processes use multiple interlinked loops rather than single positive feedback loops. Mathematical simulations revealed that linking fast and slow positive feedback loops creates a "dual-time" switch that is both rapidly inducible and resistant to noise in the upstream signaling system.