Distinct Effects of p19 RNA Silencing Suppressor on Small RNA Mediated Pathways in Plants

RNA silencing is one of the main defense mechanisms employed by plants to fight viruses. In change, viruses have evolved silencing suppressor proteins to neutralize antiviral silencing. Since the endogenous and antiviral functions of RNA silencing pathway rely on common components, it was suggested that viral suppressors interfere with endogenous silencing pathway contributing to viral symptom development. In this work, we aimed to understand the effects of the tombusviral p19 suppressor on endogenous and antiviral silencing during genuine virus infection. We showed that ectopically expressed p19 sequesters endogenous small RNAs (sRNAs) in the absence, but not in the presence of virus infection. Our presented data question the generalized model in which the sequestration of endogenous sRNAs by the viral suppressor contributes to the viral symptom development. We further showed that p19 preferentially binds the perfectly paired ds-viral small interfering RNAs (vsiRNAs) but does not select based on their sequence or the type of the 5’ nucleotide. Finally, co-immunoprecipitation of sRNAs with AGO1 or AGO2 from virus-infected plants revealed that p19 specifically impairs vsiRNA loading into AGO1 but not AGO2. Our findings, coupled with the fact that p19-expressing wild type Cymbidium ringspot virus (CymRSV) overcomes the Nicotiana benthamiana silencing based defense killing the host, suggest that AGO1 is the main effector of antiviral silencing in this host-virus combination

Effect of co-substrate feeding on methane yield of anaerobic digestion of Chlorella vulgaris

Microalgal production has many advantages over the use of terrestrial plants; therefore, increases in the use of microalgae for energy production can be expected. Algal biomass can be processed anaerobically to methane; however, the unfavorable C/N ratio of the substrate may have an inhibitory effect. The impact of the application of used cooking oil, maize silage, and mill residue on anaerobic co-digestion of the microalgal Chlorella vulgaris was studied in semi-continuous, laboratory-scale digestion. During the full period of the trial involving anaerobic digestion of algae in the case of mono-digestion and co-digestion with used cooking oil, maize silage, and mill residue, the volumetric methane yields were 0.38 ± 0.07, 1.56 ± 0.26, 1.19 ± 0.18, and 1.16 ± 0.13 L L−1, respectively. Trials were carried out to determine the long-term effect of the total solid (TS) content of substrates (co-digestion of C. vulgaris and used cooking oil at 3.8 and 7.2 % of TS, respectively). Both designs could be increased to 5.5 g VS L−1 d−1, but a higher TS% resulted in increased methane production and a longer period of decline in the methane yield due to washout. The sharp decrease in methane content at the end of 90 days was accompanied by a reorganization of the methanogenic archaeal community. © 2016 Springer Science+Business Media Dordrech

Changes in serum cytokine and cortisol levels in normothermic and hypothermic term neonates after perinatal asphyxia

OBJECTIVE: Perinatal asphyxia is characterized by an inflammatory response that contributes to cerebral injury. Therapeutic hypothermia improves neurological outcome in asphyxiated term neonates, but its clear effect on the inflammatory response is unknown. SUBJECTS AND METHODS: A range of cytokines and cortisol levels were measured at the 6th, 12th and 24th postnatal hours in neonates with hypoxic-ischemic encephalopathy treated with standard intensive care on hypothermia (n = 10) or normothermia (n = 8). The influence of postnatal age and hypothermia on serum cytokine and cortisol levels was evaluated. RESULTS: Interleukin (IL)-6 levels (at 6 h of age) and IL-4 levels (at all time points) were significantly lower in asphyxiated neonates treated with hypothermia compared to normothermic neonates. Vascular endothelial growth factor levels were higher in the hypothermia than in the normothermia group at the 6th and 12th postnatal hours. IL-10 levels decreased significantly between 6 and 24 h of age in both groups. However, no difference of IL-10 levels was observed between the study groups. The duration of hypothermia before 6 hours of age correlated with lower levels of IL-6, interferon-gamma and tumor necrosis factor-alpha measured at 6 h of age and IL-10 levels at 12 h of age. Cortisol levels did not differ between the study groups, but did gradually decrease in both groups during the study period. At 6 and 24 h of age, a positive correlation was observed between cortisol and IL-10 levels. CONCLUSIONS: Therapeutic hypothermia may rapidly suppress and modify the immediate cytokine response to asphyxia. The correlation between cytokine levels and duration of hypothermia suggests that the earlier hypothermia is introduced, the more pronounced its beneficial immunomodulatory effect

Plant virus-mediated induction of miR168 is associated with repression of ARGONAUTE1 accumulation

In response to a viral infection, plants up-regulate the expression of AGO1 to counter the infection. As part of the viral counter-defence, the virus leads to the induction of miR168, which inhibits AGO1 mRNA translation