Displaying publications 41 - 60 of 188 in total

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  1. Lau BWK, Chung JTC, Young DYN
    Family Practitioner, 1988;11:31-36.
    Matched MeSH terms: Sleep Initiation and Maintenance Disorders
  2. Abd Warif NB, Idris MYI, Abdul Wahab AW, Salleh R, Ismail A
    Forensic Sci Int, 2019 Feb;295:83-99.
    PMID: 30576953 DOI: 10.1016/j.forsciint.2018.12.004
    Taking into consideration that the prior CMF detection methods rely on several fixed threshold values in the filtering process, we propose an efficient CMF detection method with an automatic threshold selection, named as CMF-iteMS. The CMF-iteMS recommends a PatchMatch-based CMF detection method that adapts Fourier-Mellin Transform (FMT) as the feature extraction technique while a new automatic threshold selection based on iterative means of regions size (iteMS) procedure is introduced to have flexibility in changing the threshold value for various characteristics (quality, sizes, and attacks) in each input image. To ensure the reliability of the proposed CMF-iteMS, the method is compared with four state-of-the-art CMF detection methods based on Scale Invariant Feature Transform (SIFT), patch matching, multi-scale analysis and symmetry techniques using three available datasets that cover the variety of characteristics in CMF images. The results show that the F-score of the CMF-iteMS outperformed existing CMF detection methods by exceeding an average of 90% F-score values for image-level evaluation and 82% of F-score value for pixel-level evaluation for all datasets in original size. As special attention is given to the image resizing attack, the method is able to maintain the highest performance even if the images in the datasets are resized to 0.25 parameter.
    Matched MeSH terms: Maintenance
  3. Tachihana S, Nagao N, Katayama T, Hirahara M, Yusoff FM, Banerjee S, et al.
    Front Bioeng Biotechnol, 2020;8:602721.
    PMID: 33363132 DOI: 10.3389/fbioe.2020.602721
    Significantly high eicosapentaenoic acid (EPA) and fucoxanthin contents with high production rate were achieved in semi continuous culture of marine diatom. Effects of dilution rate on the production of biomass and high value biocompounds such as EPA and fucoxanthin were evaluated in semi-continuous cultures of Chaetoceros gracilis under high light condition. Cellular dry weight increased at lower dilution rate and higher light intensity conditions, and cell size strongly affected EPA and fucoxanthin contents. The smaller microalgae cells showed significantly higher (p < 0.05) value of 17.1 mg g-dw-1 fucoxanthin and 41.5% EPA content per total fatty acid compared to those observed in the larger cells. Chaetoceros gracilis can accumulate relatively higher EPA and fucoxanthin than those reported previously. In addition, maintenance of small cell size by supplying sufficient nutrients and light energy can be the key for the increase production of valuable biocompounds in C. gracilis.
    Matched MeSH terms: Maintenance
  4. Osman MA, Neoh HM, Ab Mutalib NS, Chin SF, Jamal R
    Front Microbiol, 2018;9:767.
    PMID: 29755427 DOI: 10.3389/fmicb.2018.00767
    The human gut holds the densest microbiome ecosystem essential in maintaining a healthy host physiology, whereby disruption of this ecosystem has been linked to the development of colorectal cancer (CRC). The advent of next-generation sequencing technologies such as the 16S rRNA gene sequencing has enabled characterization of the CRC gut microbiome architecture in an affordable and culture-free approach. Nevertheless, the lack of standardization in handling and storage of biospecimens, nucleic acid extraction, 16S rRNA gene primer selection, length, and depth of sequencing and bioinformatics analyses have contributed to discrepancies found in various published studies of this field. Accurate characterization of the CRC microbiome found in different stages of CRC has the potential to be developed into a screening tool in the clinical setting. This mini review aims to concisely compile all available CRC microbiome studies performed till end of 2016 and to suggest standardized protocols that are crucial in developing a gut microbiome screening panel for CRC.
    Matched MeSH terms: Maintenance
  5. Vicknasingam B, Mohd Salleh NA, Chooi WT, Singh D, Mohd Zaharim N, Kamarulzaman A, et al.
    Front Psychiatry, 2021;12:630730.
    PMID: 33854449 DOI: 10.3389/fpsyt.2021.630730
    Background: Restrictive orders and temporary programmatic or ad hoc changes within healthcare and other supportive systems that were implemented in response to the COVID-19 epidemic in Malaysia may have created hindrances to accessing healthcare and/or receiving other supportive services for people who use drugs (PWUDs). Design: A primarily qualitative study has been conducted to evaluate how service providers and recipients were adapting and coping during the initial periods of the COVID-19 response. Settings: The study engaged several healthcare and non-governmental organizations (NGOs) in the peninsular states of Penang, Kelantan, Selangor, and Melaka. Participants: Medical personnel of methadone maintenance treatment (MMT) programs (n = 2) and HIV clinics (n = 3), staff of NGO services (n = 4), and MMT patients (n = 9) were interviewed using a semi-structured format. Results: Interviewed participants reported significant organizational, programmatic, and treatment protocols related changes implemented within the healthcare and support services in addition to nationally imposed Movement Control Orders (MCOs). Changes aimed to reduce patient flow and concentration at the on-site services locations, including less frequent in-person visits, increased use of telemedicine resources, and greater reliance on telecommunication methods to maintain contacts with patients and clients; changes in medication dispensing protocols, including increased take-home doses and relaxed rules for obtaining them, or delivery of medications to patients' homes or locations near their homes were reported by the majority of study participants. No significant rates of COVID-19 infections among PWUDs, including among those with HIV have been reported at the study sites. Conclusions: Although the reported changes presented new challenges for both services providers and recipients and resulted in some degree of initial disruption, generally, all participants reported successful implementation and high levels of compliance with the newly introduced restrictions, regulations, and protocols, resulting in relatively low rates of treatment disruption or discontinuation at the study sites.
    Matched MeSH terms: Maintenance
  6. Soper FM, MacKenzie RA, Sharma S, Cole TG, Litton CM, Sparks JP
    Glob Chang Biol, 2019 Aug 29.
    PMID: 31465581 DOI: 10.1111/gcb.14813
    Mangrove forests play an important role in climate change adaptation and mitigation by maintaining coastline elevations relative to sea level rise, protecting coastal infrastructure from storm damage and storing substantial quantities of carbon (C) in live and detrital pools. Determining the efficacy of mangroves in achieving climate goals can be complicated by difficulty in quantifying C inputs (i.e., differentiating newer inputs from younger trees from older residual C pools), and mitigation assessments rarely consider potential offsets to CO2 storage by methane (CH4 ) production in mangrove sediments. The establishment of non-native Rhizophora mangle along Hawaiian coastlines over the last century offers an opportunity to examine the role mangroves play in climate mitigation and adaptation both globally and locally as novel ecosystems. We quantified total ecosystem C storage, sedimentation, accretion, sediment organic C burial and CH4 emissions from ~70 year old R. mangle stands and adjacent uninvaded mudflats. Ecosystem C stocks of mangrove stands exceeded mudflats by 434 ± 33 Mg C ha-1 , and mangrove establishment increased average coastal accretion by 460%. Sediment organic C burial increased 10-fold (to 4.5 Mg C ha-1 yr-1 ), double the global mean for old growth mangrove forests, suggesting that C accumulation from younger trees may occur faster than previously thought, with implications for mangrove restoration. Simulations indicate that increased CH4 emissions from sediments offset ecosystem CO2 storage by only 2-4%, equivalent to 30-60 Mg CO2 -eq ha-1 over mangrove lifetime (100-year sustained global warming potential). Results highlight the importance of mangroves as novel systems that can rapidly accumulate C, have a net positive atmospheric greenhouse gas removal effect, and support shoreline accretion rates that outpace current sea level rise. Sequestration potential of novel mangrove forests should be taken into account when considering their removal or management, especially in the context of climate mitigation goals.
    Matched MeSH terms: Maintenance
  7. Andiappan V, Benjamin MFD, Tan RR, Ng DKS
    Heliyon, 2019 Oct;5(10):e02594.
    PMID: 31720447 DOI: 10.1016/j.heliyon.2019.e02594
    Designers of energy systems often face challenges in balancing the trade-off between cost and reliability. In literature, several papers have presented mathematical models for optimizing the reliability and cost of energy systems. However, the previous models only addressed reliability implicitly, i.e., based on availability and maintenance planning. Others focused on allocation of reliability based on individual equipment requirements via non-linear models that require high computational effort. This work proposes a novel mixed-integer linear programming (MILP) model that combines the use of both input-output (I-O) modelling and linearized parallel system reliability expressions. The proposed MILP model can optimize the design and reliability of energy systems based on equipment function and operating capacity. The model allocates equipment with sufficient reliability to meet system functional requirements and determines the required capacity. A simple pedagogical example is presented in this work to illustrate the features of proposed MILP model. The MILP model is then applied to a polygeneration case study consisting of two scenarios. In the first scenario, the polygeneration system was optimized based on specified reliability requirements. The technologies chosen for Scenario 1 were the CHP module, reverse osmosis unit and vapour compression chiller. The total annualized cost (TAC) for Scenario 1 was 53.3 US$ million/year. In the second scenario, the minimum reliability level for heat production was increased. The corresponding results indicated that an additional auxiliary boiler must be operated to meet the new requirements. The resulting TAC for the Scenario 2 was 5.3% higher than in the first scenario.
    Matched MeSH terms: Maintenance
  8. Hmwe NT, Subramaniam P, Tan LP
    Holist Nurs Pract, 2016 Sep-Oct;30(5):283-93.
    PMID: 27501211 DOI: 10.1097/HNP.0000000000000165
    This review aimed to evaluate the effectiveness of acupressure in promoting sleep quality among adults. Study findings included in the review showed that acupressure significantly improved sleep quality compared with the control group, but no superior effect of acupressure was found compared with sham acupressure.
    Matched MeSH terms: Sleep Initiation and Maintenance Disorders/therapy*
  9. Tarusan SAA, Jidin A, Jamil MLM
    ISA Trans, 2021 Apr 16.
    PMID: 33931170 DOI: 10.1016/j.isatra.2021.04.005
    Direct Torque Control (DTC) scheme introduces a robust and simple control of electrical drive. However, its shortcomings such as broad torque ripple and variable switching frequency have offered several improvements like Space Vector Modulation (SVM) strategy, multilevel inverter (MLI) topology, etc. The conventional DTC which is fed by the two-level inverter has limited voltage vector, results in some difficulties to optimize the operation, especially at low operating speed. In contrast to MLI, the abundant of voltage vector has provided various amplitudes and angles that can overcome the problem of conventional DTC. Thus, this paper introduces the selected optimal voltage vector obtained from five-level Cascaded H-Bridge (CHB) inverter that employs in DTC hysteresis-based to achieve better optimization that similar to the DTC-SVM. Initially, the research work begins with an investigation on the performance comparison between a DTC hysteresis-based between two-level inverter (conventional method) and a five-level CHB inverter (proposed method). Here, a DC generator acted as a load is employed to control the operating speed instead of the speed controller (speed controller is negligible). Hence, the DTC method is optimized by minimizing the torque ripple as well as retaining the torque control capability at constant torque region on several operating speed. The selected optimal vector from the look-up table DTC of five-level CHB inverter must be dynamically appropriate to any change of torque (increased or decreased torque). For simplicity, this paper will only discuss the experimental results for both topologies of drive system. From the experimental results, it is verified that the torque ripples by the proposed method have achieved 10% and 50% reduction at high and low operating speed respectively. It is found that the DTC hysteresis-based result simpler control method than DTC-SVM while maintaining similar output performance.
    Matched MeSH terms: Maintenance
  10. Tran CD, Ibrahim R, Asirvadam VS, Saad N, Sabo Miya H
    ISA Trans, 2018 Apr;75:236-246.
    PMID: 29478749 DOI: 10.1016/j.isatra.2017.12.010
    The emergence of wireless technologies such as WirelessHART and ISA100 Wireless for deployment at industrial process plants has urged the need for research and development in wireless control. This is in view of the fact that the recent application is mainly in monitoring domain due to lack of confidence in control aspect. WirelessHART has an edge over its counterpart as it is based on the successful Wired HART protocol with over 30 million devices as of 2009. Recent works on control have primarily focused on maintaining the traditional PID control structure which is proven not adequate for the wireless environment. In contrast, Internal Model Control (IMC), a promising technique for delay compensation, disturbance rejection and setpoint tracking has not been investigated in the context of WirelessHART. Therefore, this paper discusses the control design using IMC approach with a focus on wireless processes. The simulation and experimental results using real-time WirelessHART hardware-in-the-loop simulator (WH-HILS) indicate that the proposed approach is more robust to delay variation of the network than the PID.
    Matched MeSH terms: Maintenance
  11. Musa NA, Moy FM, Wong LP
    Ind Health, 2018 Oct 03;56(5):407-418.
    PMID: 29848899 DOI: 10.2486/indhealth.2018-0052
    This study aimed to determine the prevalence and factors associated with poor sleep quality among secondary school teachers in the state of Selangor, Malaysia. This was a cross sectional study, conducted in two phases. Phase I tested the reliability of the Pittsburgh Sleep Quality Index in the Malay language (M-PSQI), whereas Phase II determined the prevalence and factors associated with poor sleep quality where a total of 1,871 secondary school teachers were studied. Participants were recruited using multistage sampling. Self-administered questionnaire was used to collect data on socio-demographic and teaching characteristics, comorbidities and characteristics of sleep. The M-PSQI was used to measure sleep quality. The Depression Anxiety Stress Scale-21 was used to measure mental health status. Results showed that the M-PSQI had a good internal consistency and moderate reliability. The prevalence of poor sleep quality was 61 (95% CI: 54-67)%. Total teaching hours/day, depression and stress were significantly associated with poor sleep quality in the univariate analysis, while only stress (OR 1.04; 95% CI 1.02-1.05%) remained significant in the multivariate analyses. In conclusion, stress level of the secondary school teachers should be reduced to improve sleep quality.
    Matched MeSH terms: Sleep Initiation and Maintenance Disorders/epidemiology*
  12. Norshazila, S., Irwandi, J., Othman, R., Yumi Zuhanis, H.H.
    MyJurnal
    Characterization and quantification of carotenoid compound is complicated, costly and timeconsuming. The accuracy and reliability of the data depend solely on the standard and to High Performance Liquid Chromatography (HPLC) analysis but the major constraint is to acquire and to maintain the pure standards. Carotenoid standards are commercially available but they are expensive and are prone to isomerization and oxidation. Thus, the purpose of this study is to establish an analytical method for isolating β-carotene by using open column chromatography (OCC) from pumpkin (Cucurbita moschata) to be used as one of the carotenoid standards for determination of total and individual carotenoid. Pumpkin with orange flesh has been chosen due to the non-seasonal nature and its availability all year-round. This study demonstrated that the purity of β-carotene standard; determined by HPLC was ranged from 92.21 to 97.95%. The standard curves with five different concentrations of β-carotene extract from pumpkins in triplicate were constructed by plotting the peak area against the concentration. The coefficient of correlation was 0.9936. Therefore, this study established that pumpkin can be a reliable source of beta-carotene standard as it is cheap and commonly available throughout the year.
    Matched MeSH terms: Maintenance
  13. Zakaria, M.P.M., Abas, F., Rukayadi, Y.
    MyJurnal
    The objective of this study was to investigate the effect of nutmeg (Myristica fragrans Houtt.) extract at different concentrations on chemical characteristics of raw beef under frozen storage. Nutmeg extracts at concentrations of 0.25%, 0.65%, 1.25%, 2.50% and 5.00% (g/ml) were used to treat raw beef (2.5 × 2.5 × 1.0 cm; 4 ± 0.5 g) with dilution method. Treated samples were then individually packed in overwrapped trays and stored for 3 weeks at -18 ± 1oC. The effects of the extract on the chemical characteristics such as lipid oxidation, colour, pH, moisture, fat, and protein content of raw beef were evaluated at 0, 4, 7, 10, 14 and 21 days of storage. Lipid oxidation was evaluated based on thiobarbituric acid-reactive substance (TBARS) content. Colour of beef was observed by spectrophotometer in colorimetic parameters CIELabs. Values of pH were measured using pH meter. Moisture, fat and protein content were determined using method by Analysis Association of Official Analytical Chemists (AOAC). The result showed that extract at concentration of 1.25% inhibited TBARS value meaning that extract of 1.25% or more was able to maintain the oxidative stability of beef at -18oC. A 1.25% of extract was also able to maintain the redness (a*) of treated beef compared to untreated during frozen storage. The pH values of all samples beef decreased starting from 10th day of storage. Untreated samples (0.00%) showed the lowest pH values compared to other treated samples at the end day of storage. There was no significant different in term of protein content in all treated or untreated samples. However, fat and moisture content were significantly affected by the concentration of nutmeg extract. Treated beef was able to retain its moisture with only loss of moisture ranging from 0.2% – 2.00% while untreated samples had 5.00% loss of moisture. The fat content of untreated samples (0.00%) showed a reduction of 0.2% of fat content at the end of storage compared to all treated sample with only loss of 0.1% - 0.05%. Overall, nutmeg extract can be used to maintain the chemical characteristics of raw beef during storage for 3 weeks.
    Matched MeSH terms: Maintenance
  14. Misron, L.H., Misron, K., Misron, S.N.F.
    MyJurnal
    Sleep disorder including insomnia is one of the complications of general anaesthesia. It is not uncommon and it is temporary but majority remains unnoticed and untreated. The effect of insomnia ranges from mild to severe, influencing both physical and mental health. Surgeon and anaesthetist need to identify this complication so that an appropriate treatment can be delivered. In complicated case, psychiatrist involvement is crucial. The treatment is symptomatic and temporary. We reported a case of distressful sleep disorder as a sequelae of general anaesthesia for mastoidectomy surgery. Subsequently after symptomatic treatment, he recovered completely and regained his normal sleep pattern.
    Matched MeSH terms: Sleep Initiation and Maintenance Disorders
  15. Ngen CC, Hassan R
    Int Clin Psychopharmacol, 1990 Jul;5(3):165-71.
    PMID: 2230060
    Zopiclone, a cyclopyrrolone with hypnotic properties was compared with temazepam and placebo in the treatment of insomnia. After a week's washout period, suitable subjects were allocated at random to zopiclone 7.5 mg or temazepam 20 mg or placebo for 2 weeks. Measurements of psychomotor function using the Leed's psychomotor tester and letter cancellation were carried out on day 0, 7 and 14. Sleep latency, duration of sleep and number of times waking during the night were recorded on a sleep diary filled by the subjects nightly. Forty-four subjects completed the trial, 15 taking zopiclone, 16 taking temazepam and 10 taking placebo. Both zopiclone and temazepam had significant hypnotic properties when compared to placebo. Zopiclone increased total sleep time in both weeks of the trial while temazepam increased sleep time in the first week only. There was no significant deterioration in psychomotor performance at the end of both weeks for zopiclone. Critical flicker fusion was significantly increased in subjects on temazepam. There were no abnormalities for both zopiclone and temazepam subjects in the blood picture, renal profile, liver function, urine and ECG before and after the study. Zopiclone is an effective hypnotic comparable to temazepam.
    Matched MeSH terms: Sleep Initiation and Maintenance Disorders/drug therapy*
  16. Lim JH, Chinna K, Khosla P, Karupaiah T, Daud ZAM
    PMID: 33066603 DOI: 10.3390/ijerph17207479
    Dietary non-adherence is pervasive in the hemodialysis (HD) population. Health literacy is a plausible predictor of dietary adherence in HD patients, but its putative mechanism is scarcely studied. Thus, this study aimed to establish the causal model linking nutrition literacy to dietary adherence in the HD population. This was a multi-centre, cross-sectional study, involving 218 randomly selected multi-ethnic HD patients from nine dialysis centres in Klang Valley, Malaysia. Dietary adherence and self-management skills were assessed using validated End-Stage Renal Disease Adherence Questionnaire and Perceived Kidney/Dialysis Self-Management Scale, respectively. Validated self-developed scales were used to gauge nutrition literacy, dietary knowledge and Health Belief Model constructs. Relationships between variables were examined by multiple linear regressions and partial least squares structural equation modeling. Limited nutrition literacy was evident in 46.3% of the HD patients, associated with older age, lower education level, and shorter dialysis vintage. Dietary adherence rate was at 34.9%. Nutrition literacy (β= 0.390, p < 0.001) was an independent predictor of dietary adherence, mediated by self-efficacy (SIE = 0.186, BC 95% CI 0.110-0.280) and self-management skills (SIE = 0.192, BC 95% CI 0.103-0.304). Thus, nutrition literacy-enhancing strategies targeting self-efficacy and self-management skills should be considered to enhance dietary adherence in the HD population.
    Matched MeSH terms: Maintenance
  17. Dai H, Zhang SX, Looi KH, Su R, Li J
    PMID: 32751459 DOI: 10.3390/ijerph17155498
    Research identifying adults' mental health during the coronavirus disease 2019 (COVID-19) pandemic relies solely on demographic predictors without examining adults' health condition as a potential predictor. This study aims to examine individuals' perception of health conditions and test availability as potential predictors of mental health-insomnia, anxiety, depression, and distress-during the COVID-19 pandemic. An online survey of 669 adults in Malaysia was conducted during 2-8 May 2020, six weeks after the Movement Control Order (MCO) was issued. We found adults' perception of health conditions had curvilinear relationships (horizontally reversed J-shaped) with insomnia, anxiety, depression, and distress. Perceived test availability for COVID-19 also had curvilinear relationships (horizontally reversed J-shaped) with anxiety and depression. Younger adults reported worse mental health, but people from various religions and ethnic groups did not differ significantly in reported mental health. The results indicated that adults with worse health conditions had more mental health problems, and the worse degree deepened for unhealthy people. Perceived test availability negatively predicted anxiety and depression, especially for adults perceiving COVID-19 test unavailability. The significant predictions of perceived health condition and perceived COVID-19 test availability suggest a new direction for the literature to identify the psychiatric risk factors directly from health-related variables during a pandemic.
    Matched MeSH terms: Sleep Initiation and Maintenance Disorders
  18. Mat Zain NS, Lee LK
    Int J Environ Res Public Health, 2022 Dec 06;19(23).
    PMID: 36498443 DOI: 10.3390/ijerph192316371
    Aquaculture is seen as an essential food-producing sector for improving global food security and nutrition indices. This cross-sectional study examined the health complaints and mental health status of aquaculture workers, as well as their relationship with quality of life, with respect to the brackish water and freshwater aquaculture cultivation system in Penang, Malaysia. The workers’ health complaints were collected, and mental health status was evaluated as means of depression, anxiety, stress and self-esteem. Self-perceived quality of life was assessed using a structured questionnaire. This study involved the participation of 88 brackish water (84.6%) and 16 freshwater (15.4%) aquaculture workers. A total of 72.7% of the brackish water aquaculture workers were aged beyond 50 years old and had worked within five years (77.3%) in the aquaculture industry. Both brackish water and freshwater cultivation workers were confronted with fatigue, pain and insomnia. Up to 48%, 40.4%, 26% and 24% of them were facing depression, anxiety, stress and low self-esteem, respectively. A total of 3.4% of the brackish water aquaculture workers were having bad quality of life. The complaints of neck/shoulder/arm pain (F = 13.963; p < 0.001), back pain (F = 10.974; p < 0.01), hand/wrist pain (F = 8.041; p < 0.01), knee/hip pain (F = 12.910; p < 0.01) and insomnia (F = 10.936; p < 0.01) were correlated with bad quality of life among the workers. For mental health status, self-esteem (F = 4.157; p < 0.05) was found to be negatively correlated with quality of life scores. The results outlined the concerning level of health complaints and psychological distress among the aquaculture workers. The study emphasized the importance of developing an appropriate occupational health strategy in the aquaculture industry. Longitudinal investigations aimed to explore the effects of psychological distress on employment productivity among the high-risk workers are warranted.
    Matched MeSH terms: Sleep Initiation and Maintenance Disorders*
  19. Ling CF, Radin Umar RZ, Ahmad N
    Int J Occup Saf Ergon, 2020 Dec 29.
    PMID: 33096963 DOI: 10.1080/10803548.2020.1840116
    Objective. Limited models are available to predict work-relatedness of musculoskeletal disorders (MSDs) among semiconductor back-end workers. This study aims to develop a model to predict the MSDs development among back-end workers. Method. Potential MSD risk factors were extracted from 277 work compensation investigation reports conducted between 2011-2019. Binary logistic regression approach was used to determine significant predictors. Results. Significant predictors (p 
    Matched MeSH terms: Maintenance
  20. Wong CF, Rahman RNZRA, Basri M, Salleh AB
    Iran J Biotechnol, 2017;15(3):194-200.
    PMID: 29845069 DOI: 10.15171/ijb.1524
    Background:Pseudomonas protein expression in E. coli is known to be a setback due to significant genetic variation and absence of several genetic elements in E. coli for regulation and activation of Pseudomonas proteins. Modifications in promoter/repressor system and shuttle plasmid maintenance have made the expression of stable and active Pseudomonas protein possible in both Pseudomonas sp. and E. coli. Objectives: Construction of shuttle expression vectors for regulation and overexpression of Pseudomonas proteins in Pseudomonas sp. and E. coli. Materials and Methods:Pseudomonas-Escherichia shuttle expression vectors, pCon2(3), pCon2(3)-Kan and pCon2(3)-Zeo as well as E. coli expression vectors of pCon4 and pCon5 were constructed from pUCP19-, pSS213-, pSTBlue-1- and pPICZαA-based vectors. Protein overexpression was measured using elastase strain K as passenger enzyme in elastinolytic activity assay. Results: The integration of two series of IPTG inducible expression cassettes in pCon2(3), pCon2(3)-Kan and pCon2(3)-Zeo, each carrying an E. coli lac-operon based promoter, Plac, and a tightly regulated T7(A1/O4/O3) promoter/repressor system was performed to facilitate overexpression study of the organic solvent-tolerant elastase strain K. These constructs have demonstrated an elastinolytic fold of as high as 1464.4 % in comparison to other published constructs. pCon4 and pCon5, on the other hand, are series of pCon2(3)-derived vectors harboring expression cassettes controlled by PT7(A1/O4/O3) promoter, which conferred tight regulation and repression of basal expression due to existence of respective double operator sites, O3 and O4, and lacIq. Conclusions: The constructs offered remarkable assistance for overexpression of heterogeneous genes in Pseudomonas sp. and E. coli for downstream applications such as in industries and structural biology study.
    Matched MeSH terms: Maintenance
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