UV-induced DNA damage promotes resistance to the biotrophic pathogen Hyaloperonospora parasitica in Arabidopsis

Plant innate immunity to pathogenic microorganisms is activated in response to recognition of extracellular or intracellular pathogen molecules by transmembrane receptors or resistance proteins, respectively. The defense signaling pathways share components with those involved in plant responses to UV radiation, which can induce expression of plant genes important for pathogen resistance. Such intriguing links suggest that UV treatment might activate resistance to pathogens in normally susceptible host plants. Here, we demonstrate that pre-inoculative UV (254 nm) irradiation of Arabidopsis (Arabidopsis thaliana) susceptible to infection by the biotrophic oomycete Hyaloperonospora parasitica, the causative agent of downy mildew, induces dose- and time-dependent resistance to the pathogen detectable up to 7 d after UV exposure. Limiting repair of UV photoproducts by postirradiation incubation in the dark, or mutational inactivation of cyclobutane pyrimidine dimer photolyase, (6-4) photoproduct photolyase, or nucleotide excision repair increased the magnitude of UV-induced pathogen resistance. In the absence of treatment with 254-nm UV, plant nucleotide excision repair mutants also defective for cyclobutane pyrimidine dimer or (6-4) photoproduct photolyase displayed resistance to H. parasitica, partially attributable to short wavelength UV-B (280–320 nm) radiation emitted by incubator lights. These results indicate UV irradiation can initiate the development of resistance to H. parasitica in plants normally susceptible to the pathogen and point to a key role for UV-induced DNA damage. They also suggest UV treatment can circumvent the requirement for recognition of H. parasitica molecules by Arabidopsis proteins to activate an immune response.

Developing and validating a questionnaire to measure spirituality : a psychometric process

The purpose of the paper is to describe the processes undertaken to evaluate the psychometric properties of a questionnaire developed to measure spirituality and examine the relationship between spirituality and coping in young adults with diabetes.

The specific validation processes used were: content and face validity, construct validity using factor analysis, reliability and internal consistency using test-retest reliability and Cronbach’s alpha correlation coefficient.

The exploratory factor analysis revealed four factors: self-awareness, the importance of spiritual beliefs, spiritual practices, and spiritual needs. The items on the Spirituality Questionnaire (SQ) revealed factor loading ≥ 0.5. Reliability processes indicated that the SQ is reliable: Cronbach’s alpha 0.94 for the global SQ and between 0.80-0.91 for the four subscales. Test-retest statistic examination revealed stability of the responses at two time points 10 weeks apart.

The final questionnaire consists of 29 items and the psychometrics indicated that it is valid and reliable.

Isolation of sperms from the pollen tube of flowering plants during fertilization

Sperm cells have been isolated from pollen tubes growing in style segments of the dicotlyledon Rhododendron macgregoriae and the monocotyledon Gladiolus gandavensis by the in vivo/in vitro method at various stages of fertilization. Pollen tubes emerged from the cut end of the style into agar medium, and more than 95% contained sperm cells. Sperm cells were released from the pollen tubes by osmotic shock or by placing styles in wall-degrading enzymes: 0.5% macerozyme and 1% cellulase. The isolated sperms were ellipsoidal protoplasts of diameter about 2 × 3 micrometers in Gladiolus and about 3 × 4 micrometers in Rhododendron. After isolation, a proportion of the sperm cells occurred in pairs linked at one end by finger-like connections. The pairs of isolated sperms were dimorphic in terms of surface area and volume. By cutting the styles at various positions and times after pollination, the potential exists to detect changes in sperm gene expression associated with fertilization.

Corrosion properties of a RF-magnetron-sputtered TiN coating deposited on 316L stainless steel

The effect of rf-power in the range from 100 to 200 W on the electrochemical properties of TiN coatings deposited on 316L stainless steel was investigated by using various electrochemical techniques in a 3.5-wt\% NaCl solution. Surface analyses were also conducted to analyze the coating characteristics. X-ray diffraction (XRD) and atomic force microscopy (AFM) analyses confirmed that increasing the rf-power led to a preferred orientation of the TiN(200) microstructure and decreased the surface roughness. The potentiodynamic test results confirmed the passive behavior of all of the specimens with low passive current densities and demonstrated that the effective pitting resistance of the TiN coatings increased with increasing rf-power. The electrochemical impedance spectroscopy (EIS) tests showed that the TiN films deposited with high rf-power had excellent corrosion resistance during an immersion time of 720 h due to their high total resistance and low porosity.

MEDIATOR25 acts as an integrative hub for the regulation of jasmonate-responsive gene expression in arabidopsis

The PHYTOCHROME AND FLOWERING TIME1 gene encoding the MEDIATOR25 (MED25) subunit of the eukaryotic Mediator complex is a positive regulator of jasmonate (JA)-responsive gene expression in Arabidopsis (Arabidopsis thaliana). Based on the function of the Mediator complex as a bridge between DNA-bound transcriptional activators and the RNA polymerase II complex, MED25 has been hypothesized to function in association with transcriptional regulators of the JA pathway. However, it is currently not known mechanistically how MED25 functions to regulate JA-responsive gene expression. In this study, we show that MED25 physically interacts with several key transcriptional regulators of the JA signaling pathway, including the APETALA2 (AP2)/ETHYLENE RESPONSE FACTOR (ERF) transcription factors OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF59 and ERF1 as well as the master regulator MYC2. Physical interaction detected between MED25 and four group IX AP2/ERF transcription factors was shown to require the activator interaction domain of MED25 as well as the recently discovered Conserved Motif IX-1/EDLL transcription activation motif of MED25-interacting AP2/ERFs. Using transcriptional activation experiments, we also show that OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF59- and ERF1-dependent activation of PLANT DEFENSIN1.2 as well as MYC2-dependent activation of VEGETATIVE STORAGE PROTEIN1 requires a functional MED25. In addition, MED25 is required for MYC2-dependent repression of pathogen defense genes. These results suggest an important role for MED25 as an integrative hub within the Mediator complex during the regulation of JA-associated gene expression.

A Cross-Cultural Evaluation of the Personal Wellbeing Index – School Children in Samples of Australian and Portuguese Adolescents

The practice of comparing nations on subjective wellbeing (SWB) is becoming commonplace, with many countries ranked by economists and social scientists alike according to average levels of SWB based on survey responses. Such large, multi-national population surveys have the potential to generate insights into the causes and correlates of SWB within different cultural groups, as well as inform policy regarding how to improve the wellbeing of citizens. At the heart of these large-scale research endeavors are SWB measures that function equivalently between the various participating cultural groups. For this reason, it is concerning that their remains a paucity of research that supports measurement equivalence for many SWB instruments commonly employed. Thus, it remains unclear whether variations in SWB across cultures reflect true differences, or whether these differences reflect measurement biases (e.g., response bias inherent within a particular cultural group). The aim of this study was to examine the psychometric equivalence of the Personal Wellbeing Index–School Children (PWI-SC) in convenience samples of Australian and Portuguese adolescents using multiple-group confirmatory factor analysis. Participants comprising the Australian sample were 1104 Victorian high-school students aged between 12 and 19 years (M = 14.42, SD = 1.63). Participants comprising the Portuguese sample were 573 high-school students living in Portugal aged between 12 and 18 years (M = 14.32, SD = 1.72). The results demonstrated strict factorial invariance between both versions of the PWI-SC, suggesting that this scale measures the same underlying construct in both samples. Moreover, these findings provide preliminary support for quantitative comparisons between Australian and Portuguese adolescents on the SWB variable as valid.