Distribution of glyphosate and of its target enzyme inside wheat plants

Enolpyruvylshikimate phosphate (EPSP) synthase activity has been measured in different organs of 1–14-day-old wheat seedlings growing in culture chambers. Enzyme activity was first detected after two days, and reached its maximum value at day 4. It remained almost unchanged for 14 days thereafter. During germination, one of the most important sources of enzyme was the seed scutellum. Later, the developed leaves contained 43% of the whole stock of enzyme. Although the enzyme distribution was not identical under light or in the dark, there was no evident light induction of EPSP synthase. High enzyme activity was found in the coleoptile, continuing for the whole life-time of this organ, and which might be associated with its lignification. Five to 40% of the total enzyme was found in the roots, reaching a maximum at 14 days. At this stage, glyphosate applied to the first grown leaf was phloem-transported to the sink organs, with no clear relationship being shown between EPSP synthase activity and herbicide quantity in each organ. At day 4, glyphosate treatment, by soaking the seedlings in the herbicide solution, was followed by an active phloem transport from the scutellum to the growing parts. The average internal concentration of radiolabelled compounds (glyphosate plus its possible derivatives) which induced wheat seedling growth decrease, was shown to reach 50 to 100 μM under our conditions.     

Synthetic Aperture Radar (SAR) images improve habitat suitability models

Context

The ability to detect ecological networks in landscapes is of utmost importance for managing biodiversity and planning corridors.

Objectives

The objective of this study was to evaluate the information provided by a synthetic aperture radar (SAR) image for landscape connectivity modeling compared to aerial photographs (APs).

Methods

We present a novel method that integrates habitat suitability derived from remote sensing imagery into a connectivity model to explain species abundance. More precisely, we compared how two resistance maps constructed using landscape and/or local metrics derived from AP or SAR imagery yield different connectivity values (based on graph theory), considering hedgerow networks and forest carabid beetle species as a model.

Results

We found that resistance maps using landscape and local metrics derived from SAR imagery improve landscape connectivity measures. The SAR model is the most informative, explaining 58% of the variance in forest carabid beetle abundance. This model calculates resistance values associated with homogeneous patches within hedgerows according to their suitability (canopy cover density and landscape grain) for the model species.

Conclusions

Our approach combines two important methods in landscape ecology: the construction of resistance maps and the use of buffers around sampling points to determine the importance of landscape factors. This study was carried out through an interdisciplinary approach involving remote sensing scientists and landscape ecologists. This study is a step forward in developing landscape metrics from satellites to monitor biodiversity.

     

United States Department of Agriculture-Agricultural Research Service research programs on microbes for management of plant-parasitic nematodes

Restrictions on the use of conventional nematicides have increased the need for new methods of managing plant-parasitic nematodes. Consequently, nematode-antagonistic microbes, and active compounds produced by such organisms, are being explored as potential additions to management practices. Programs in this area at the USDA Agricultural Research Service investigate applied biocontrol agents, naturally occurring beneficial soil microbes and natural compounds. Specific research topics include use of plant growth-promoting rhizobacteria and cultural practices for management of root-knot and ring nematodes, determination of management strategies that enhance activity of naturally occurring Pasteuria species (bacterial obligate parasites of nematodes), studies on interactions between biocontrol bacteria and bacterial-feeding nematodes, and screening of microbes for compounds active against plant-parasitic nematodes. Some studies involve biocontrol agents that are active against nematodes and soil-borne plant-pathogenic fungi, or combinations of beneficial bacteria and fungi, to manage a spectrum of plant diseases or to increase efficacy over a broader range of environmental conditions. Effective methods or agents identified in the research programs are investigated as additions to existing management systems for plant-parasitic nematodes.     

A new furovirus infecting barley in France closely related to the Japanese soil-borne wheat mosaic virus

In April 2001, stunted barley plants bearing mosaic symptoms were observed in a field in France (Marne Department, 51). Rod-shaped and flexuous particles were visualized by electron microscopy and positive serological reactions were detected by ELISA with Barley yellow mosaic virus (BaYMV) and Soil-borne cereal mosaic virus (SBCMV) polyclonal antisera. The tubular virus which was soil transmissible to barley cv. Esterel was separated from BaYMV by serial mechanical inoculations to barley cv. Esterel. This furo-like virus, in contrast to a French isolate of SBCMV, could be transmitted to Hordeum vulgare, Avena sativa, Beta vulgaris and Datura stramonium. RT-PCR was used to amplify the 3′-terminal 1500 nucleotides of RNA1 and the almost complete sequence of RNA2. Nucleotide and amino acid sequence analyses revealed that the French virus infecting barley is closely related to a Japanese isolate of Soil-borne wheat mosaic virus (SBWMV-JT) which was originally isolated from barley. This French isolate was named SBWMV-Mar. The 3′ UTRs of both RNAs can be folded into tRNA-like structures which are preceded by a predicted upstream pseudoknot domain with seven and four pseudoknots for RNA1 and RNA2, respectively. The four pseudoknots strongly conserved in RNAs 1 and 2 of SBWMV-Mar show strong similarities to those described earlier in SBWMV RNA2 and were also found in the 3′ UTR of Oat golden stripe virus RNAs 1 and 2 and Chinese wheat mosaic virus RNA2. Sequence analyses revealed that the RNAs 2 of SBWMV-Mar and -JT are likely to be the product of a recombination event between the 3′ UTRs of the RNAs 2 of SBWMV and SBCMV. This is the first report of the occurrence of an isolate closely related to SBWMV-JT outside of Japan.     

Usefulness of serological examinations in the analysis of Salmonella infections in pig herds

The development of the antibody concentration against lipopolysaccharide (LPS) of S. Typhimurium und S. Choleraesuis in rearing pigs during the fattening period and in breeding sows of the corresponding age was recorded. The studies revealed the following results. Antibodies of isotypes IgG1 and IgG2 revealed a more pronounced specificity against the according Salmonella serovar than IgM antibodies. The calculated "antibody percent value" based on the total amount of Salmonella antibodies is mainly determined by the IgM antibodies in sera and meat juice, respectively. In fattening pigs a significant increase of antibodies against IgM and total Ig was observed between week 3 and 10 after beginning of the rearing period. In breeding pigs this increase was detectable already earlier. In only 3 out of 10 groups an increase of IgG1 and IgG2 was also seen. The detected significant increase of total Ig and IgM in the other groups might be the result of a less intensive exposure to salmonellas or it might be due to an increase of unspecific antibodies induced by other antigens. Serological investigations represent a valuable tool to record the intensity and development in time of the Salmonella exposure in pigs farms. Examination of total Ig is an appropriate method to detect pig herds with a high level of Salmonella exposure, for detailed epidemiological studies in pig farms the examination of antibody isotypes will give more comprehensive information.     

Preputial fibroma in a gelding

An 11‐year‐old gelding presented with a large mass located in the dermis of his preputium that surrounded the penis completely. This mass was first noted years ago but did not increase in size. Histological examination diagnosed a fibroma. No treatment was initiated since no signs of discomfort were noticed and the gelding was performing at a high level in competitive showjumping. Next to skin tumours, tumours of the penis and preputium are most common. Most frequently, squamous cell carcinomas and sarcomas are diagnosed. Although fibromas can develop anywhere in connective tissue, a preputial location of a fibroma in a gelding is rare. Differential diagnosis and possible treatment options are discussed.     

Molecular analysis of the Arbuscular mycorrhiza symbiosis

The molecular analysis of the arbuscular mycorrhizal (AM) symbiosis started at the beginning of this decade. The paper summarises the work of the ‘Laboratorium für Molekulare Genetik arbuskulärer Mykorrhiza’ at the MPI für terrestrische Mikrobiologie in Marburg on three major topics. Firstly, the plant response to the mycorrhizal colonisation was analysed using both, targeted and non‐targeted approaches. As an example, the localisation of the gst1 mRNA in potato mycorrhiza is shown. Second, molecular techniques were established to analyse gene expression of the fungal partner of the symbiosis. We present a differential RNA display analysis of spore germination in two AM fungi and the cloning of a gene from Glomus mosseae that shows expression at all stages of the fungal life cycle. In the last part, we introduce the work we are carrying out with a new root endophytic fungus, Piriformospora indica. Infection experiments on maize showed that despite the fungus performs as a root necrotroph, it has a positive effect on plant growth.     

Dwarf shrub litter as a food source for macro-decomposers in alpine pastureland

Dwarf shrub litter is thought to be of poor quality and palatability for macro-decomposers. In laboratory feeding experiments, however, it was found that this litter type represents a potential food source for earthworms and millipedes. Here we tested whether this is true under natural conditions by conducting a 1 year field experiment on an abandoned alpine pasture in Tyrol (Austria). As the natural isotopic signatures of plant litter do not allow discriminating between different plant species, dwarf shrub litter, artificially enriched in ¹⁵N, was offered in experimental plots to the macro-decomposer community. Both the earthworm Lumbricus rubellus and the millipede Cylindrojulus fulviceps fed on dwarf shrub litter as indicated by their increased δ¹⁵N signatures, but IsoError analysis indicated a clear preference for grass litter for all macro-decomposer species investigated.Soil δ¹⁵N signatures were only marginally affected by the experimental provision of ¹⁵N-enriched dwarf shrub litter, whereas litter from other, unlabelled, plants became enriched by the isotopic tracer to some extent. Except for one grass species, plants harvested at the end of the experiment were not enriched in ¹⁵N, suggesting that the N-uptake from decomposing litter material by plants on abandoned alpine pastureland is slow.     

Veterinarians teaching at schools of agriculture in Germany (up to 1950)--their contribution to animal nutrition

During the 19th century in Germany mainly veterinarians working at agricultural schools or appointed to veterinary schools from there (for example HAUBNER, ROLOFF, DAMMANN, ALBRECHT, KRONACHER) made considerable contributions to the development of animal nutrition. They disseminated knowledge of feedstuffs and feeding techniques to the interested public at large by books concerning animal husbandry and especially "Gesundheitspflege" (health regimen; Tab. 1). Their experimental work (Tab. 2) extended from digestibility of feedstuffs, Ca-, P- and rumen metabolism (NPN), respectively, to feed intoxications. The interest in preventive measures being stronger at school of agriculture than at veterinary schools probably stimulated this development.     

Livestock nutrient management concerns: regulatory and legislative overview

A greater focus on manure nutrient disposition from concentrated animal-feeding operations has developed from environmentalists, concerned citizens, and regulatory agencies. The establishment and enforcement of manure nutrient regulations will alter the future of livestock production. Proposed legislation and strategies may provide a false sense of security regarding environmental preservation or restoration and may impose monitoring and record keeping on the livestock operators. Existing regulations and proposed regulations and strategies are presented. Implications of legislation and proposed strategies, policies, and regulations are discussed. Livestock operations will need to comply with regulations to remain in business and to minimize environmental liability.