N-acyl-homoserine lactones-producing bacteria protect plants against plant and human pathogens

The implementation of beneficial microorganisms for plant protection has a long history. Many rhizobia bacteria are able to influence the immune system of host plants by inducing resistance towards pathogenic microorganisms. In this report, we present a translational approach in which we demonstrate the resistance-inducing effect of Ensifer meliloti (Sinorhizobium meliloti) on crop plants that have a significant impact on the worldwide economy and on human nutrition. Ensifer meliloti is usually associated with root nodulation in legumes and nitrogen fixation. Here, we suggest that the ability of S. meliloti to induce resistance depends on the production of the quorum-sensing molecule, oxo-C14-HSL. The capacity to enhanced resistance provides a possibility to the use these beneficial bacteria in agriculture. Using the Arabidopsis-Salmonella model, we also demonstrate that the application of N-acyl-homoserine lactones-producing bacteria could be a successful strategy to prevent plant-originated infections with human pathogens.     

Protocol for X-ray dosimetry and exposure arrangements employed in studies of late somatic effects in mammals

A number of European laboratories studying the late effects of ionizing radiation in animals have established an effective cooperation within the European Late Effects Project Group (EULEP) since 1970. To facilitate the exchange of biological results several techniques, including quality control of the experimental animals, pathology and dosimetry, have to be standardized. The most important aspects of the procedures for X-irradiation and dosimetry of small animals are summarized. These include recommendations on irradiation conditions, dosimetry methods, characteristics of phantoms and factors affecting X-ray dosimetry. X-irradiation procedures employed by the participating institutes are described and the results of five X-ray dosimetry intercomparisons are reported. The introduction of a common dosimetry protocol has resulted in improvements in exposure arrangements and absolute dosimetry.     

The phospholipid code: a key component of dying cell recognition,tumor progression and host–microbe interactions

A significant effort is made by the cell to maintain certain phospholipids at specific sites. It is well described that proteins involved in intracellular signaling can be targeted to the plasma membrane and organelles through phospholipid-binding domains. Thus, the accumulation of a specific combination of phospholipids, denoted here as the ‘phospholipid code'', is key in initiating cellular processes. Interestingly, a variety of extracellular proteins and pathogen-derived proteins can also recognize or modify phospholipids to facilitate the recognition of dying cells, tumorigenesis and host–microbe interactions. In this article, we discuss the importance of the phospholipid code in a range of physiological and pathological processes.     

Influence of N-fertilization and Fungicide Strategies on Fusarium Head Blight Severity and Mycotoxin Content in Winter Wheat

Nitrogen (N) fertilization and fungicide applications are still subject to discussion concerning the influence on Fusarium head blight (FHB) and related mycotoxin accumulation. Field studies were made in 2000–2001 and 2001–2002 to investigate the effect of two N‐rates and 11 plant protection treatments on FHB severity and the content of FHB‐related mycotoxins, namely deoxynivalenol (DON) and zearalenone (ZEA) under conditions of natural infection. The treatments applied can be summarized as (i) an integrated approach using a decision support system, (ii) the use of two plant strengtheners, Bion^® (benzo [1,2,3]thiadiazole‐7‐carbothioic acid S‐methyl‐ester, BTH) and a compound based on the biomass of the cyanobacterium Spirulina platensis, (iii) the use of plant strengtheners in combination with a broad‐spectrum fungicide and (iv) common fungicide strategies against foliar diseases. Fusarium infections as well as the analysed mycotoxins were observed at low levels in both years. Disease severity was significantly increased by conventional N‐fertilization only in 2001. Neither FHB severity nor mycotoxin accumulation was significantly influenced by any of the treatments, although treatments without fungicides appeared to lead to lower disease severities. In 2002, there was a tendency towards higher disease severities when common fungicide strategies were applied. Mycotoxin contamination was found in grain samples from both years. In 2001 DON was mainly traceable, whereas in 2002 ZEA was also detected. Mycotoxin contamination was influenced by N‐fertilization rather than by the treatments. In 2001, the DON content was significantly increased due to the conventional N‐supply. Our results indicate that less intensive fungicide strategies, including plant strengtheners, are no worse than common fungicide strategies under conditions of low FHB severity and mycotoxin accumulation. Immoderate N‐fertilization however, can increase mycotoxin levels significantly even under conditions unfavourable for Fusarium spp.