Ethylene supports colonization of plant roots by the mutualistic fungus Piriformospora indica

The mutualistic basidiomycete Piriformospora indica colonizes roots of mono- and dicotyledonous plants, and thereby improves plant health and yield. Given the capability of P. indica to colonize a broad range of hosts, it must be anticipated that the fungus has evolved efficient strategies to overcome plant immunity and to establish a proper environment for nutrient acquisition and reproduction. Global gene expression studies in barley identified various ethylene synthesis and signaling components that were differentially regulated in P. indica-colonized roots. Based on these findings we examined the impact of ethylene in the symbiotic association. The data presented here suggest that P. indica induces ethylene synthesis in barley and Arabidopsis roots during colonization. Moreover, impaired ethylene signaling resulted in reduced root colonization, Arabidopsis mutants exhibiting constitutive ethylene signaling, -synthesis or ethylene-related defense were hyper-susceptible to P. indica. Our data suggest that ethylene signaling is required for symbiotic root colonization by P. indica

Huddle Up: Using Mediation to Help Settle the National Football League Labor Dispute

In a patient transferred from Togo to Cologne, Germany, Lassa fever was diagnosed 12 days post mortem. Sixty-two contacts in Cologne were categorised according to the level of exposure, and gradual infection control measures were applied. No clinical signs of Lassa virus infection or Lassa specific antibodies were observed in the 62 contacts. Thirty-three individuals had direct contact to blood, other body fluids or tissue of the patients. Notably, with standard precautions, no transmission occurred between the index patient and healthcare workers. However, one secondary infection occurred in an undertaker exposed to the corpse in Rhineland-Palatinate, who was treated on the isolation unit at the University Hospital of Frankfurt. After German authorities raised an alert regarding the imported Lassa fever case, an American healthcare worker who had cared for the index patient in Togo, and who presented with diarrhoea, vomiting and fever, was placed in isolation and medevacked to the United States. The event and the transmission of Lassa virus infection outside of Africa underlines the need for early diagnosis and use of adequate personal protection equipment (PPE), when highly contagious infections cannot be excluded. It also demonstrates that larger outbreaks can be prevented by infection control measures, including standard PPE

Ozone and ultraviolet B effects on the defense-related proteins β-1,3-glucanase and chitinase in tobacco

The air pollutant ozone is a potent abiotic inducer of defense-related enzymes such as pathogenesis-related proteins. Here we report on the accumulation of beta-1,3-glucanase and chitinase in Nicotiana tabacum L. treated with ozone and ultraviolet B radiation, singly and in combination, under a simulated sunlight spectrum. Ozone (0.16 mu L . L(-1), 2 x 5 h) induced the basic isoforms of beta-1,3-glucanase in both, ozone-sensitive (Eel W3) and -tolerant (Bel B) cultivars, while chitinase was only affected in cv. Bel W3. Ultraviolet B radiation (7.5 MED) alone did not lead to beta-1,3-glucanase or chitinase induction. In combined treatments ultraviolet B increased the ozone-dependent lesion formation and reduced chitinase accumulation in the sensitive cv. Bel W3. Analysis of the intercellular washing fluid of ozone-treated plants revealed the accumulation of a major ozone-related protein (O(3)R-1) of 28 kDa within 32 h. Microsequence analysis of two tryptic peptides showed 100 % homology to acidic chitinase PR-3b. These results indicate that basic beta-1,3-glucanase and chitinase are distinctly regulated in ozone and ultraviolet B treated tobacco, and that ultraviolet B radiation with a similar UV edge as the solar spectrum does not lead to an accumulation of basic pathogenesis-related proteins

Oxidative stress, heat shock and drought differentially affect expression of a tobacco protein phosphatase 2C

A protein phosphatase 2C (PP2C)-homologous cDNA was isolated from Nicotiana tabacum (NtPP2C1). The deduced protein sequence of 416 amino acids showed the highest degree of similarity to the PP2C of Arabidopsis thaliana (AtPP2CA) implicated in abscisic acid signalling. The expression of NtPP2C1 was strongly induced by drought, but repressed by oxidative stress and heat shock. It is suggested that NtPP2C1 operates at the junction of drought, heat shock and oxidative stress

Maize glutathione-dependent formaldehyde dehydrogenase: protein sequence and catalytic properties

Glutathione-dependent formaldehyde dehydrogenase (FDH; EC 1.2.1.1) has been purified 3900-fold from maize cell-suspension cultures to a specific activity of 4.68 mu mol (mg protein)(-1) min(-1). The homogeneous enzyme consisted of two identical subunits with a molecular mass of 42 kDa, and an isoelectric point of 5.8. Eight tryptic peptides were sequenced and gave a perfect fit to the protein sequence derived from maize Fdh cDNA (J. Fliegmann and H. Sandermann, 1997, Slant Mol Biol 34: 843-854). There was 62% identity with the eucaryotic FDH consensus sequence. Michaelis constants of approx. 20 mu m (formaldehyde), approx; 50 mu m (glutathione) and approx. 31 mu m (NAD(+)) were determined for the maize enzyme as well as for FDH partially purified from dog lung. Besides S-hydroxymethylglutathione, pentanol-1, octanol-1, and omega-hydroxy-fatty acids served as substrates for both FDH preparations. The unusual substrate specificity indicates that FDH may be involved in the detoxification of long-chain lipid peroxidation products