Untargeted Lipidomic Analysis to Broadly Characterize the Effects of Pathogenic and Non-Pathogenic Staphylococci on Mammalian Lipids

Modification of the host lipidome via secreted enzymes is an integral, but often overlooked aspect of bacterial pathogenesis. In the current era of prevalent antibiotic resistance, knowledge regarding critical host pathogen lipid interactions has the potential for use in developing novel antibacterial agents. While most studies to date on this matter have focused on specific lipids, or select lipid classes, this provides an incomplete picture. Modern methods of untargeted lipidomics have the capacity to overcome these gaps in knowledge and provide a comprehensive understanding of the role of lipid metabolism in the pathogenesis of infections. In an attempt to determine the role of lipid modifying enzymes produced by staphylococci, we exposed bovine heart lipids, a standardized model for the mammalian lipidome, to spent medium from staphylococcal cultures, and analyzed lipid molecular changes by MS/MSALLshotgun lipidomics. We elucidate distinct effects of different staphylococcal isolates, including 4 clinical isolates of the pathogenic species Staphylococcus aureus, a clinical isolate of the normally commensal species S. epidermidis, and the non-pathogenic species S. carnosus. Two highly virulent strains of S. aureus had a more profound effect on mammalian lipids and modified more lipid classes than the other staphylococcal strains. Our studies demonstrate the utility of the applied untargeted lipidomics methodology to profile lipid changes induced by different bacterial secretomes. Finally, we demonstrate the promise of this lipidomics approach in assessing the specificity of bacterial enzymes for mammalian lipid classes. Our data suggests that there may be a correlation between the bacterial expression of lipid-modifying enzymes and virulence, and could facilitate the guided discovery of lipid pathways required for bacterial infections caused by S. aureus and thereby provide insights into the generation of novel antibacterial agents

Distinct emphysema subtypes defined by quantitative CT analysis are associated with specific pulmonary matrix metalloproteinases.

BACKGROUND: Emphysema is characterised by distinct pathological sub-types, but little is known about the divergent underlying aetiology. Matrix-metalloproteinases (MMPs) are proteolytic enzymes that can degrade the extracellular matrix and have been identified as potentially important in the development of emphysema. However, the relationship between MMPs and emphysema sub-type is unknown. We investigated the role of MMPs and their inhibitors in the development of emphysema sub-types by quantifying levels and determining relationships with these sub-types in mild-moderate COPD patients and ex/current smokers with preserved lung function. METHODS: Twenty-four mild-moderate COPD and 8 ex/current smokers with preserved lung function underwent high resolution CT and distinct emphysema sub-types were quantified using novel local histogram-based assessment of lung density. We analysed levels of MMPs and tissue inhibitors of MMPs (TIMPs) in bronchoalveolar lavage (BAL) and assessed their relationship with these emphysema sub-types. RESULTS: The most prevalent emphysema subtypes in COPD subjects were mild and moderate centrilobular (CLE) emphysema, while only small amounts of severe centrilobular emphysema, paraseptal emphysema (PSE) and panlobular emphysema (PLE) were present. MMP-3, and -10 associated with all emphysema sub-types other than mild CLE, while MMP-7 and -8 had associations with moderate and severe CLE and PSE. MMP-9 also had associations with moderate CLE and paraseptal emphysema. Mild CLE occurred in substantial quantities irrespective of whether airflow obstruction was present and did not show any associations with MMPs. CONCLUSION: Multiple MMPs are directly associated with emphysema sub-types identified by CT imaging, apart from mild CLE. This suggests that MMPs play a significant role in the tissue destruction seen in the more severe sub-types of emphysema, whereas early emphysematous change may be driven by a different mechanism. TRIAL REGISTRATION: Trial registration number NCT01701869

Lamb Wave Imaging and V(Z) Using a Broadband System

The work reported here has been motivated by the need to characterise thin ceramic coatings on metallic substrates. In addition to measuring the elastic constants of the coating, which among other things is dependent on the deposition technique, it is desirable to inspect the condition of the interface between the coating and the substrate. One deposition technique involves plasma-spraying of the ceramic onto a grit-blasted metal surface. Although the top surface of the film can be polished for ultrasonic inspection, the film/substrate interface will be very rough. The Lamb wave V(z) technique has been demonstrated to be effective for the calculation of the elastic constants of thin films on substrates. The effect of surface roughness on the Lamb wave dispersion curves must be well understood however, before this method can be applied to the problem of interest here. As such, a series of tests have been performed on glass slides that have different degrees of roughness introduced on one surface

Isolation and detection of taxol, an anticancer drug produced from Lasiodiplodia theobromae, an endophytic fungus of the medicinal plant Morinda citrifolia

To determine the production of taxol from an endophytic fungus, Lasiodiplodia theobromae isolated from the medicinal plant Morinda citrifolia and also, to evaluate its cytotoxicity against human breast cancer cell line, taxol produced by the test fungus in MID culture medium was isolated for its characterization. The presence of taxol was confirmed by different chromatographic and spectroscopic analyses. The quantity of taxol produced by the fungus was calculated and estimated to be 245 μg/l. The fungal taxol was tested for its bioactivity against human cancer cell line (MCF-7) and the results showed that, the taxol possessed anticancer activity. The production of taxol was achieved from an endophytic fungus, L. theobromae. The screened taxol showed a potential toxicity against breast cancer cell lines. Fungal based production of taxol from an endophytic fungus would be the most desirable and alternate source of supply. This study proved that the fungal endophyte L. theobromae is an excellent candidate for an alternate source of taxol supply. Confirmations of the in vitro activity of taxol against human breast cancer cell lines should encourage further research. Furthermore, it is the first report of the screening of taxol from the fungus L. theobromae, isolated from the medicinal plant M. citrifolia.Key words: Endophytic fungus, Lasiodiplodia theobromae, anticancer drug, taxol production, cytotoxicity test

Mixed Methods Action Research: Intervention Strategies for Employee Turnover in Ethnic Asian Enterprises in New Zealand

Excessive employee turnover can pose a threat to a firm’s growth and survival. This is particularly true for small ethnic Asian businesses that rely heavily on human labour input with cultural and language challenges. This paper sets out to develop effective intervening strategies for the high labour turnover found in ABC (pseudonym), a small ethnic Asian company in New Zealand that provides commercial cleaning and shopping trolley collections services. This study used a multistrand mixed method action research (MMAR) approach that leverages discussions, a survey and interviews for data collection in the cycle of action research (AR) proposed by Coghlan and Brannick: 'constructing' (Phase 1), 'planning action' (Phase 2), 'taking action' (Phase 3), and 'evaluating action' (Phase 4). This design helps cross-validate the gathered data and enhance the rigour and credibility of the research outcomes. In Phase 1, having identified excessively high employee turnover as the research problem, the subsequent literature review revealed three candidate intervening variables: leadership styles, job satisfaction and level of ethnic entrepreneurship (co-ethnic community involvement). In Phase 2, data were collected and analyzed using a mixed method to understand the impact of the intervening variables on turnover and identify the areas for improvement when applying the found-to-be effective variables in ABC. The quantitative data was collected from employees of ethnic Asian companies including ABC. The statistical analyses on 222 usable questionnaires suggested that two variables (leadership styles – supportive and participative, and job satisfaction) were found to be the strong predictors of employee withdrawal intention. Interestingly, it was not possible from the data to claim a moderating effect of ethnic entrepreneurship on the relationships between leadership and turnover propensity. The succeeding qualitative study gathered the data from twelve ABC employees via phone. The interview results were largely aligned with the quantitative findings. They confirmed the beneficial effect of supportive and participative leadership styles on job satisfaction, and highlighted the detrimental effect of the directive style. In phase 3, the meta-inferences gained from merging the outcomes of Phase 2 were validated in ABC’s context through the discussions with ABC executives. These yielded three feasible action plans with six strategies to tackle employee turnover under leadership styles and job satisfaction categories: taking leadership training, facilitating effective communication systems (changing the frequencies and mode of the communications), and providing non-monetary rewards (free snacks, job titles, and celebrating personal and work milestones). In phase 4, the suggested action plans are evaluated and consideration is given for future research. Overall, this MMAR study fulfilled its objective of producing context-specific outcomes to my real work context. At the same time, it has contributed to the body of knowledge by extending the Western and large organisation oriented turnover study, to the small ethnic Asian companies in New Zealand. However, the suggested strategies are not the final solutions to the problem, and measuring their effect remains a task for future research as the second cycle of action research (AR)

Duel and sweep algorithm for order-preserving pattern matching

Given a text $T$ and a pattern $P$ over alphabet $\Sigma$, the classic exact matching problem searches for all occurrences of pattern $P$ in text $T$. Unlike exact matching problem, order-preserving pattern matching (OPPM) considers the relative order of elements, rather than their real values. In this paper, we propose an efficient algorithm for OPPM problem using the "duel-and-sweep" paradigm. Our algorithm runs in $O(n + m\log m)$ time in general and $O(n + m)$ time under an assumption that the characters in a string can be sorted in linear time with respect to the string size. We also perform experiments and show that our algorithm is faster that KMP-based algorithm. Last, we introduce the two-dimensional order preserved pattern matching and give a duel and sweep algorithm that runs in $O(n^2)$ time for duel stage and $O(n^2 m)$ time for sweeping time with $O(m^3)$ preprocessing time.Comment: 13 pages, 5 figure

Observation of the thermal Casimir force

Quantum theory predicts the existence of the Casimir force between macroscopic bodies, due to the zero-point energy of electromagnetic field modes around them. This quantum fluctuation-induced force has been experimentally observed for metallic and semiconducting bodies, although the measurements to date have been unable to clearly settle the question of the correct low-frequency form of the dielectric constant dispersion (the Drude model or the plasma model) to be used for calculating the Casimir forces. At finite temperature a thermal Casimir force, due to thermal, rather than quantum, fluctuations of the electromagnetic field, has been theoretically predicted long ago. Here we report the experimental observation of the thermal Casimir force between two gold plates. We measured the attractive force between a flat and a spherical plate for separations between 0.7 $\mu$m and 7 $\mu$m. An electrostatic force caused by potential patches on the plates' surfaces is included in the analysis. The experimental results are in excellent agreement (reduced $\chi^2$ of 1.04) with the Casimir force calculated using the Drude model, including the T=300 K thermal force, which dominates over the quantum fluctuation-induced force at separations greater than 3 $\mu$m. The plasma model result is excluded in the measured separation range.Comment: 6 page

Use of archival versus newly collected tumor samples for assessing PD-L1 expression and overall survival : an updated analysis of KEYNOTE-010 trial

Background: In KEYNOTE-010, pembrolizumab versus docetaxel improved overall survival (OS) in patients with programmed death-1 protein (PD)-L1-positive advanced non-small-cell lung cancer (NSCLC). A prespecified exploratory analysis compared outcomes in patients based on PD-L1 expression in archival versus newly collected tumor samples using recently updated survival data. Patients and methods: PD-L1 was assessed centrally by immunohistochemistry (22C3 antibody) in archival or newly collected tumor samples. Patients received pembrolizumab 2 or 10 mg/kg Q3W or docetaxel 75 mg/m2 Q3W for 24 months or until progression/intolerable toxicity/other reason. Response was assessed by RECIST v1.1 every 9 weeks, survival every 2 months. Primary end points were OS and progression-free survival (PFS) in tumor proportion score (TPS) 50% and 1%; pembrolizumab doses were pooled in this analysis. Results: At date cut-off of 24 March 2017, median follow-up was 31 months (range 23-41) representing 18 additional months of follow-up from the primary analysis. Pembrolizumab versus docetaxel continued to improve OS in patients with previously treated, PD-L1-expressing advanced NSCLC; hazard ratio (HR) was 0.66 [95% confidence interval (CI): 0.57, 0.77]. Of 1033 patients analyzed, 455(44%) were enrolled based on archival samples and 578 (56%) on newly collected tumor samples. Approximately 40% of archival samples and 45% of newly collected tumor samples were PD-L1 TPS 50%. For TPS 50%, the OS HRs were 0.64 (95% CI: 0.45, 0.91) and 0.40 (95% CI: 0.28, 0.56) for archival and newly collected samples, respectively. In patients with TPS 1%, OS HRs were 0.74 (95% CI: 0.59, 0.93) and 0.59 (95% CI: 0.48, 0.73) for archival and newly collected samples, respectively. In TPS 50%, PFS HRs were similar across archival [0.63 (95% CI: 0.45, 0.89)] and newly collected samples [0.53 (95% CI: 0.38, 0.72)]. In patients with TPS 1%, PFS HRs were similar across archival [0.82 (95% CI: 0.66, 1.02)] and newly collected samples [0.83 (95% CI: 0.68, 1.02)]. Conclusion: Pembrolizumab continued to improve OS over docetaxel in intention to treat population and in subsets of patients with newly collected and archival samples

Bidirectional signaling of neuregulin-2 mediates formation of GABAergic synapses and maturation of glutamatergic synapses in newborn granule cells of postnatal hippocampus

Expression of neuregulin-2 (NRG2) is intense in a few regions of the adult brain where neurogenesis persists; however, little is understood about its role in developments of newborn neurons. To study the role of NRG2 in synaptogenesis at different developmental stages, newborn granule cells in rat hippocampal slice cultures were labeled with retrovirus encoding tetracycline-inducible microRNA targeting NRG2 and treated with doxycycline (Dox) at the fourth or seventh postinfection day (dpi). The developmental increase of GABAergic postsynaptic currents (GPSCs) was suppressed by the early Dox treatment (4 dpi), but not by late treatment (7 dpi). The late Dox treatment was used to study the effect of NRG2 depletion specific to excitatory synaptogenesis. The Dox effect on EPSCs emerged 4 d after the impairment in dendritic outgrowth became evident (10 dpi). Notably, Dox treatment abolished the developmental increases of AMPA-receptor mediated EPSCs and the AMPA/NMDA ratio, indicating impaired maturation of glutamatergic synapses. In contrast to GPSCs, Dox effects on EPSCs and dendritic growth were independent of ErbB4 and rescued by concurrent overexpression of NRG2 intracellular domain. These results suggest that forward signaling of NRG2 mediates GABAergic synaptogenesis and its reverse signaling contributes to dendritic outgrowth and maturation of glutamatergic synapses.117Ysciescopu