Cloning, high-level expression, purification and characterization of a staphylokinase variant, SakøC, from Staphylococcus aureus QT08 in Escherichia coli BL21

The staphylokinase (Sak) is emerging as an important thrombolytic agent for the treatment of patients suffering from cardiovascular disease. Hence in this study, we reported the cloning, high-level expression, purification and characterization of the Sak variant SakøC from Staphylococcus aureus QT08 in Escherichia coli Bl21. The sak gene of 489 bp encoding a protein (163 amino acids) with a predicted molecular mass of 18.5 kDa and pI 7.28 showed 99.8 to 99.6% identity with corresponding sequences from S. aureus strains deposited in GenBank (AF332619, X00127, EF122253 and M57455). The DNA sequence (411 bp) encoding the mature Sak (15.5 kDa) truncated 27 N-terminal amino acids was expressed in E. coli BL21/pESak under the control of the strong promoter tac in the presence of isopropyl-β-D-1-thiogalactopynoside (IPTG) as inducer. The expression level of rSak was estimated at about 42% of the total cellular proteins by densitometry scanning, which is the highest expression level of rSak expressed in any E. coli system. The recombinant staphylokinase was purified by Ni2+- ProBondTM column to a single homogeneous 16-kDa band on sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) with a specific activity of 15175 U/mg protein, a recovery yield of 58% and a purification factor of 2.56. The optimal pH and temperature for the rSak activity was 9 and 37°C, respectively. rSak was stable over a temperature range of 25 to 50°C and at pH range of 7 to 9. Metal ions and detergents also showed an inhibitory effect on rSak, especially Zn2+ and Cu2+ which completely inhibited the enzymatic activity.Key words: Staphylococcus aureus QT08, staphylokinase, cloning, high-level expression, purification, characterization

Special Issue: Real World Application of SHM in Australia

Australian Network of Structural Health Monitoring (ANSHM) was established in 2009 to promote and advance the field of SHM in Australia and the association has grown considerably since then. By November of 2018, ANSHM has the membership made of 45 organisations including 20 universities, 16 private companies, 6 road authorities and 3 research institutions. Every year ANSHM organises an annual workshop and/or conference sessions for members to exchange their research and practical developments in SHM. One edited book and nine journal special issues have been produced since the establishment of ANSHM. One of these special issues was organised in Structural Health Monitoring - an International Journal (SHMIJ) in 2014. On 6–7 December 2017, ANSHM held its 9th annual workshop as part of the prestigious 8th International Conference on Structural Health Monitoring of Intelligent Infrastructures (SHMII-8) in Brisbane, Queensland, Australia. The main focus of both SHMII-8 and the 9th ANSHM workshop was SHM in real-world application. Interestingly, all sessions of SHMII-8 and ANSHM workshop were held within the P block building at Gardens Point Campus of Queensland University of Technology (QUT) that was instrumented with Australia's first ever long-term full-scale SHM system. Inspired by this theme and high-quality presentations at the workshop, a special issue named 'Real World Application of SHM in Australia' was established in SHMIJ and the 9th ANSHM workshop speakers were invited to submit enhanced and extended versions of their papers to this Special Issue. After rigorous pre-screening, peer review and revision processes, fourteen papers were accepted for inclusion in the Special Issue. The contributions include deterioration assessment of the instrumented P block building at QUT using hybrid model updating and long-term vibration monitoring data, reliability-based load-carrying capacity assessment of bridges using SHM and non-linear analysis, and innovative vibration based damage identification methods with applications to cable-stayed, steel-truss or timber bridges as well as to frame, utility-pole or building structures. The Special Issue also includes new research on non-destructive evaluation of (i) incipient pitting corrosion in reinforced concrete structures, (ii) gaps between carbon fibre reinforced polymer composite and concrete surfaces, (iii) fatigue cracks in pipes, (iv) bolted joints, and (v) in-situ stress. Most studies were verified on real civil structures or large-scale laboratory models well reflecting the high applicability of the developed methods to solve real-world problems. As the guest editors of this Special Issue, we thank the authors for their contribution and all the anonymous reviewers who provided constructive review comments to the manuscripts submitted to this Special Issue. We would also like to express our sincere gratitude to the Managing Editor Professor Michael Todd and the journal executive committee for their support and assistance during the submission and review process. Finally, we would like to thank the SAGE Publications team for their diligence in assuring the efficient and timely production of the papers toward the publication of this Special Issue

Model informed quantification of the feed-forward stimulation of growth hormone by growth hormone-releasing hormone

Aims: Growth hormone (GH) secretion is pulsatile and secretion varies highly between individuals. To understand and ultimately predict GH secretion, it is important to first delineate and quantify the interaction and variability in the biological processes underlying stimulated GH secretion. This study reports on the development of a population nonlinear mixed effects model for GH stimulation, incorporating individual GH kinetics and the stimulation of GH by GH-releasing hormone (GHRH). Methods: Literature data on the systemic circulation, the median eminence, and the anterior pituitary were included as system parameters in the model. Population parameters were estimated on data from 8 healthy normal weight and 16 obese women who received a 33 μg recombinant human GH dose. The next day, a bolus injection of 100 μg GHRH was given to stimulate GH secretion. Results: The GH kinetics were best described with the addition of 2 distribution compartments with a bodyweight dependent clearance (increasing linearly from 24.7 L/h for a 60-kg subject to 32.1 L/h for a 100-kg subject). The model described the data adequately with high parameter precision and significant interindividual variability on the GH clearance and distribution volume. Additionally, high variability in the amount of secreted GH, driven by GHRH receptor activation, was identified (coefficient of variation = 90%). Conclusion: The stimulation of GH by GHRH was quantified and significant interindividual variability was identified on multiple parameters. This model sets the stage for further development of by inclusion of additional physiological components to quantify GH secretion in humans

Very sensitive fiber Bragg grating accelerometer using transverse forces with an easy over-range protection and low cross axial sensitivity

2013-2014 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Complete genome characterization of two wild-type measles viruses from Vietnamese infants during the 2014 outbreak

A large measles virus outbreak occurred across Vietnam in 2014. We identified and obtained complete measles virus genomes in stool samples collected from two diarrheal pediatric patients in Dong Thap Province. These are the first complete genome sequences of circulating measles viruses in Vietnam during the 2014 measles outbreak

Genome sequences of a novel Vietnamese bat bunyavirus

To document the viral zoonotic risks in Vietnam, fecal samples were systematically collected from a number of mammals in southern Vietnam and subjected to agnostic deep sequencing. We describe here novel Vietnamese bunyavirus sequences detected in bat feces. The complete L and S segments from 14 viruses were determined

Combination of inflammatory and vascular markers in the febrile phase of dengue is associated with more severe outcomes

Background: Early identification of severe dengue patients is important regarding patient management and resource allocation. We investigated the association of 10 biomarkers (VCAM-1, SDC-1, Ang-2, IL-8, IP-10, IL-1RA, sCD163, sTREM-1, ferritin, CRP) with the development of severe/moderate dengue (S/MD). Methods: We performed a nested case-control study from a multi-country study. A total of 281 S/MD and 556 uncomplicated dengue cases were included. Results: On days 1–3 from symptom onset, higher levels of any biomarker increased the risk of developing S/MD. When assessing together, SDC-1 and IL-1RA were stable, while IP-10 changed the association from positive to negative; others showed weaker associations. The best combinations associated with S/MD comprised IL-1RA, Ang-2, IL-8, ferritin, IP-10, and SDC-1 for children, and SDC-1, IL-8, ferritin, sTREM-1, IL-1RA, IP-10, and sCD163 for adults. Conclusions: Our findings assist the development of biomarker panels for clinical use and could improve triage and risk prediction in dengue patients. Funding: This study was supported by the EU's Seventh Framework Programme (FP7-281803 IDAMS), the WHO, and the Bill and Melinda Gates Foundation

Climate-related corporate reporting and cost of equity capital

Purpose: This study aims to examine the reaction of stakeholders (i.e. capital providers) to climate-related corporate reporting. Climate-related corporate reporting is captured by the level of voluntary carbon disclosure, while the recognition and appreciation of capital providers are captured through the cost of equity capital (COE). Design/methodology/approach: This study uses a sample including the 350 largest companies by market capitalization on the London Stock Exchange, UK (FTSE350) from 2015 to 2019. The authors use fixed-effects regression models to examine the effect of climate-related corporate reporting on the COE. Findings: This study finds that voluntary carbon disclosure proxied by carbon disclosure score is negatively associated with COE. This suggests that firms’ superior quality disclosure of carbon information could contribute to a lower COE. This implies that the market and stakeholders positively appreciate the involvement in climate-related reporting by businesses. Originality/value: The finding provides insights to regulators, investors and other stakeholders in terms of the positive economic implication of actively engaging in reducing climate change impact through voluntary carbon disclosure. These findings also motivate corporates to be proactively involved in climate-related reporting by extending the quality of carbon information disclosure

A Prognostic Model for Development of Profound Shock among Children Presenting with Dengue Shock Syndrome

PURPOSE: To identify risk factors and develop a prediction model for the development of profound and recurrent shock amongst children presenting with dengue shock syndrome (DSS). METHODS: We analyzed data from a prospective cohort of children with DSS recruited at the Paediatric Intensive Care Unit of the Hospital for Tropical Disease in Ho Chi Minh City, Vietnam. The primary endpoint was "profound DSS", defined as ≥2 recurrent shock episodes (for subjects presenting in compensated shock), or ≥1 recurrent shock episodes (for subjects presenting initially with decompensated/hypotensive shock), and/or requirement for inotropic support. Recurrent shock was evaluated as a secondary endpoint. Risk factors were pre-defined clinical and laboratory variables collected at the time of presentation with shock. Prognostic model development was based on logistic regression and compared to several alternative approaches. RESULTS: The analysis population included 1207 children of whom 222 (18%) progressed to "profound DSS" and 433 (36%) had recurrent shock. Independent risk factors for both endpoints included younger age, earlier presentation, higher pulse rate, higher temperature, higher haematocrit and, for females, worse hemodynamic status at presentation. The final prognostic model for "profound DSS" showed acceptable discrimination (AUC=0.69 for internal validation) and calibration and is presented as a simple score-chart. CONCLUSIONS: Several risk factors for development of profound or recurrent shock among children presenting with DSS were identified. The score-chart derived from the prognostic models should improve triage and management of children presenting with DSS in dengue-endemic areas