Spatial imaging of Zn and other elements in Huanglongbing-affected grapefruit by synchrotron-based micro X-ray fluorescence investigation

Huanglongbing (HLB) is a highly destructive, fast-spreading disease of citrus, causing substantial economic losses to the citrus industry worldwide. Nutrient levels and their cellular distribution patterns in stems and leaves of grapefruit were analysed after graft-inoculation with lemon scions containing 'Candidatus Liberibacter asiaticus' (Las), the heat-tolerant Asian type of the HLB bacterium. After 12 months, affected plants showed typical HLB symptoms and significantly reduced Zn concentrations in leaves. Micro-XRF imaging of Zn and other nutrients showed that preferential localization of Zn to phloem tissues was observed in the stems and leaves collected from healthy grapefruit plants, but was absent from HLB-affected samples. Quantitative analysis by using standard references revealed that Zn concentration in the phloem of veins in healthy leaves was more than 10 times higher than that in HLB-affected leaves. No significant variation was observed in the distribution patterns of other elements such as Ca in stems and leaves of grapefruit plants with or without graft-inoculation of infected lemon scions. These results suggest that reduced phloem transport of Zn is an important factor contributing to HLB-induced Zn deficiency in grapefruit. Our report provides the first in situ, cellular level visualization of elemental variations within the tissues of HLB-affected citrus. © 2014 © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology

Blended learning in dentistry: 3-D resources for inquiry-based learning

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Anticancer Activity of Linalool Terpenoid: Apoptosis Induction and Cell Cycle Arrest in Prostate Cancer Cells

Purpose: To evaluate the anticancer activity of linalool against human prostate cancer (DU145) cells.Methods: The anticancer activity of linalool against DU145 cancer cells was evaluated by 3-(4, 5- dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Flow cytometry, using propidium iodide and Annexin V-FITC, was applied to study apoptosis and cell cycle phase distribution. Inverted light microscopy was used to study the effect of linalool on cell morphology and apoptotic body formation in DU145 cells while gel electrophoresis was employed to evaluate the effect of linalool on DNA fragmentation.Results: Linalool induced a dose-dependent as well as time-dependent growth inhibitory effect on DU145 prostate cancer cells. It induced sub-G1 phase growth arrest which led to increase in sub-G0/G1 cell population after treatment with increasing doses of linalool. DNA ladder appeared to be more evident with increasing linalool concentration. However, no DNA fragments were observed in the control groups. It was observed that 4.36, 11.54, 21.88 and 15.54 % of the cells underwent early apoptosis after treatment with 0 (no linalool treatment), 20, 40, and 80 μM of linalool, respectively. Compared to control cells, linalool treatment resulted in the appearance of cell shrinkage along with membrane blebbing which are characteristic features of cell apoptosis.Conclusion: The findings of this study indicate that linalool can be developed as a plant-based chemotherapeutic agent against prostate cancerKeywords: Prostate cancer, Linalool, Chemotherapy, Cell cycle, Apoptosis, DNA fragmentation, Sub- G1 phase growt

Tooth eruption and obesity in 12-year-old children

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Development of stable marker-free nuclear transformation strategy in the green microalga Chlorella vulgaris

Although microalgae have valuable resources with great necessity in many biotechnological applications, no tools have been developed yet for a stable genetic transformation without antibiotic marker genes in these organisms. Chlorella is one of the most useful genus for biotechnological applications. The transfer of foreign DNA (vector or linear DNA cassette) into Chlorella by electroporation has very low stability and it is hard to screen the transformants without antibiotic marker genes. However, the marker genes have some disadvantages to host cells. To avoid the negative effects caused by the marker genes, we tried to develop a stable marker-free nuclear transformation system in Chlorella. For this, linear gene expression cassettes (LGEC) were constructed with functional domains, which are responsible for transformation, of SV40 large T antigen. The LGECs were transferred into Chlorella via electroporation and durability of the LGECs were confirmed in transgenic Chlorella. Transcription levels of the LGECs were also determined at different cell cycle sates. The LGECs integrated into the chromosomal DNA of Chlorella were stably replicated and were expressed successfully at G0-, G1-, and G2-phases. This study presents a stable marker-free nuclear transformation system with potential for biotechnological applications.Key words: Chlorella vulgaris, marker-free nuclear transformation, SV40 large T antigen, microalga

Mechanisms of cognitive trust development in artificial intelligence among front line employees: An empirical examination from a developing economy

Drawing upon insights from the trust literature, we conducted two empirical surveys with the front-line employees of firms in Pakistan investigating the factors influencing cognitive trust in artificial intelligence (AI). Study1 consisted of 46 in-depth interviews aimed at exploring factors influencing cognitive trust. Based on the findings of Study 1, we developed a framework to enhance employees’ cognitive trust in AI. We then conducted a quantitative survey (study 2) with 314 employees to validate the proposed model. The findings suggest that AI features positively influence the cognitive trust of employees, while work routine disruptions have negative impact on cognitive trust in AI. The effectiveness of data governance was also found to facilitate employees' trust in data governance and subsequently, employees' cognitive trust in AI. We contribute to the technology trust literature, especial in developing economics. We discuss the implications of our findings for both research and practice

Unsupervised binning of environmental genomic fragments based on an error robust selection of l-mers

BACKGROUND: With the rapid development of genome sequencing techniques, traditional research methods based on the isolation and cultivation of microorganisms are being gradually replaced by metagenomics, which is also known as environmental genomics. The first step, which is still a major bottleneck, of metagenomics is the taxonomic characterization of DNA fragments (reads) resulting from sequencing a sample of mixed species. This step is usually referred as 'binning'. Existing binning methods are based on supervised or semi-supervised approaches which rely heavily on reference genomes of known microorganisms and phylogenetic marker genes. Due to the limited availability of reference genomes and the bias and instability of marker genes, existing binning methods may not be applicable in many cases. RESULTS: In this paper, we present an unsupervised binning method based on the distribution of a carefully selected set of l-mers (substrings of length l in DNA fragments). From our experiments, we show that our method can accurately bin DNA fragments with various lengths and relative species abundance ratios without using any reference and training datasets. Another feature of our method is its error robustness. The binning accuracy decreases by less than 1% when the sequencing error rate increases from 0% to 5%. Note that the typical sequencing error rate of existing commercial sequencing platforms is less than 2%. CONCLUSIONS: We provide a new and effective tool to solve the metagenome binning problem without using any reference datasets or markers information of any known reference genomes (species). The source code of our software tool, the reference genomes of the species for generating the test datasets and the corresponding test datasets are available at http://i.cs.hku.hk/alse/MetaCluster/.published_or_final_versio

Luminescent Cyclometalated Gold(III) Alkyl Complexes: Photophysical and Photochemical Properties

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Localized surface optical phonon mode in the InGaN/GaN multiple-quantum- wells nanopillars: Raman spectrum and imaging

An interesting phonon mode at around 685-705 cm -1 was clearly observed in the Raman spectra of InGaN/GaN multiple-quantum-wells nanopillars with different diameters at room temperature. The Raman peak position of this mode is found to show a distinct dependence on the nanopillar size, which is in well agreement with theoretical calculation of the surface optical (SO) phonon modes of nanopillars. Moreover, this kind of SO phonon was evidenced to be located on the pillar surface by using scanning confocal micro-Raman microscopy. © 2011 American Institute of Physics.published_or_final_versio