Nuclear localization of NPR1 is required for activation of PR gene expression

Systemic acquired resistance (SAR) is a broad-spectrum resistance in plants that involves the upregulation of a battery of pathogenesis-related (PR) genes. NPR1 is a key regulator in the signal transduction pathway that leads to SAR. Mutations in NPR1 result in a failure to induce PR genes in systemic tissues and a heightened susceptibility to pathogen infection, whereas overexpression of the NPR1 protein leads to increased induction of the PR genes and enhanced disease resistance. We analyzed the subcellular localization of NPR1 to gain insight into the mechanism by which this protein regulates SAR. An NPR1–green fluorescent protein fusion protein, which functions the same as the endogenous NPR1 protein, was shown to accumulate in the nucleus in response to activators of SAR. To control the nuclear transport of NPR1, we made a fusion of NPR1 with the glucocorticoid receptor hormone binding domain. Using this steroid-inducible system, we clearly demonstrate that nuclear localization of NPR1 is essential for its activity in inducing PR genes.

Combined mitochondrial and nuclear DNA sequences resolve the interrelations of the major Australasian marsupial radiations

Australasian marsupials include three major radiations, the insectivorous/carnivorous Dasyuromorphia, the omnivorous bandicoots (Peramelemorphia), and the largely herbivorous diprotodontians. Morphologists have generally considered the bandicoots and diprotodontians to be closely related, most prominently because they are both syndactylous (with the 2nd and 3rd pedal digits being fused). Molecular studies have been unable to confirm or reject this Syndactyla hypothesis. Here we present new mitochondrial (mt) genomes from a spiny bandicoot (Echymipera rufescens) and two dasyurids, a fat-tailed dunnart (Sminthopsis crassicaudata) and a northern quoll (Dasyurus hallucatus). By comparing trees derived from pairwise base-frequency differences between taxa with standard (absolute, uncorrected) distance trees, we infer that composition bias among mt protein-coding and RNA sequences is sufficient to mislead tree reconstruction. This can explain incongruence between trees obtained from mt and nuclear data sets. However, after excluding major sources of compositional heterogeneity, both the “reduced-bias” mt and nuclear data sets clearly favor a bandicoot plus dasyuromorphian association, as well as a grouping of kangaroos and possums (Phalangeriformes) among diprotodontians. Notably, alternatives to these groupings could only be confidently rejected by combining the mt and nuclear data. Elsewhere on the tree, Dromiciops appears to be sister to the monophyletic Australasian marsupials, whereas the placement of the marsupial mole (Notoryctes) remains problematic. More generally, we contend that it is desirable to combine mt genome and nuclear sequences for inferring vertebrate phylogeny, but as separately modeled process partitions. This strategy depends on detecting and excluding (or accounting for) major sources of nonhistorical signal, such as from compositional nonstationarity.

S-allylmercaptocysteine reduces carbon tetrachloride-induced hepatic oxidative stress and necroinflammation via nuclear factor kappa B-dependent pathways in mice.

Purpose To study the protective effects and underlying molecular mechanisms of SAMC on carbon tetrachloride (CCl4)-induced acute hepatotoxicity in the mouse model. Methods Mice were intraperitoneally injected with CCl4 (50 μl/kg; single dose) to induce acute hepatotoxicity with or without a 2-h pre-treatment of SAMC intraperitoneal injection (200 mg/kg; single dose). After 8 h, the blood serum and liver samples of mice were collected and subjected to measurements of histological and molecular parameters of hepatotoxicity. Results SAMC reduced CCl4-triggered cellular necrosis and inflammation in the liver under histological analysis. Since co-treatment of SAMC and CCl4 enhanced the expressions of antioxidant enzymes, reduced the nitric oxide (NO)-dependent oxidative stress, and inhibited lipid peroxidation induced by CCl4. SAMC played an essential antioxidative role during CCl4-induced hepatotoxicity. Administration of SAMC also ameliorated hepatic inflammation induced by CCl4 via inhibiting the activity of NF-κB subunits p50 and p65, thus reducing the expressions of pro-inflammatory cytokines, mediators, and chemokines, as well as promoting pro-regenerative factors at both transcriptional and translational levels. Conclusions Our results indicate that SAMC mitigates cellular damage, oxidative stress, and inflammation in CCl4-induced acute hepatotoxicity mouse model through regulation of NF-κB. Garlic or garlic derivatives may therefore be a potential food supplement in the prevention of liver damage.

Bomb disposal in the tropics : a cocktail of metabolic and environmental heat

Bomb technicians perform their work while encapsulated in explosive ordnance disposal (EOD) suits. Designed primarily for safety, these suits have an unintended consequence of impairing the body’s natural mechanisms for heat dissipation. Purpose: To quantify the heat strain encountered during an EOD operational scenario in the tropical north of Australia. Methods: All active police male bomb technicians, located in a tropical region of Australia (n=4, experience 7 ± 2.1 yrs, age 34 ± 2 yrs, height 182.3 ± 5.4 cm, body mass 95 ± 4 kg, VO2max 46 ± 5.7 ml.kg-1.min-1) undertook an operational scenario wearing the Med-Eng EOD 9 suit and helmet (~32 kg). The climatic conditions ranged between 27.1–31.8°C ambient temperature, 66-88% relative humidity, and 30.7-34.3°C wet bulb globe temperature. The scenario involved searching a two story non air-conditioned building for a target; carrying and positioning equipment for taking an X-ray; carrying and positioning equipment to disrupt the target; and finally clearing the site. Core temperature and heart rate were continuously monitored, and were used to calculate a physiological strain index (PSI). Urine specific gravity (USG) assessed hydration status and heat associated symptomology were also recorded. Results: The scenario was completed in 121 ± 22 mins (23.4 ± 0.4% work, 76.5 ± 0.4% rest/recovery). Maximum core temperature (38.4 ± 0.2°C), heart rate (173 ± 5.4 bpm, 94 ± 3.3% max), PSI (7.1 ± 0.4) and USG (1.031 ± 0.002) were all elevated after the simulated operation. Heat associated symptomology highlighted that moderate-severe levels of fatigue and thirst were universally experienced, muscle weakness and heat sensations experienced by 75%, and one bomb technician reported confusion and light-headedness. Conclusion: All bomb technicians demonstrated moderate-high levels of heat strain, evidenced by elevated heart rate, core body temperature and PSI. Severe levels of dehydration and noteworthy heat-related symptoms further highlight the risks to health and safety faced by bomb technicians operating in tropical locations.