Displaying publications 41 - 60 of 823 in total

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  1. Intestinal carriage of multidrug-resistant gram-negative bacteria in preterm-infants during hospitalization in neonatal intensive care unit (NICU)
    Yap PS, Ahmad Kamar A, Chong CW, Yap IK, Thong KL, Choo YM, et al.
    Pathog Glob Health, 2016 Sep;110(6):238-246.
    PMID: 27650884
    The prevalence and antibiotic susceptibility of intestinal carriage of Gram-negative bacteria among preterm infants admitted to the neonatal intensive care unit (NICU) in a tertiary teaching hospital in Malaysia were determined. A total of 34 stool specimens were obtained from preterm infants upon admission and once weekly up to two weeks during hospitalization. The presumptive colonies of Escherichia coli and Klebsiella pneumoniae were selected for identification, antibiotic susceptibility testing, and subtyping by using pulsed-field gel electrophoresis (PFGE). Out of 76 Gram-negative isolates, highest resistance was detected for amoxicillin/clavulanate (30.8%, n = 16), ceftriaxone (42.3%, n = 22), ceftazidime (28.8%, n = 15), cefoxitin (28.8%, n = 15), aztreonam (36.5%, n = 19), and polymyxin B (23.1%, n = 12). Three colistin resistant K. pneumoniae have also been detected based on E-test analysis. Thirty-nine isolates of K. pneumoniae and 20 isolates of E. coli were resistant to more than three antimicrobial classes and were categorized as multidrug resistant (MDR). PFGE analysis revealed a higher diversity in pulsotypes for K. pneumoniae (18 pulsotypes) in comparison to E. coli (four pulsotypes). In addition, a total of fifteen pulsotypes was observed from 39 MDR K. pneumoniae. The risk factors for antibiotic resistance were assessed using random forest analysis. Gender was found to be the most important predictor for colistin resistant while length, OFC, and delivery mode were showing greater predictive power in the polymyxin B resistance. This study revealed worrying prevalence rates of intestinal carriage of multidrug-resistant K. pneumoniae and E. coli of hospitalized preterm infants in Malaysia, particularly high resistance to polymyxins.
    Matched MeSH terms: Escherichia coli/drug effects; Escherichia coli/isolation & purification
  2. Purification of long helical capsid of newcastle disease virus from Escherichia coli using anion exchange chromatography
    Yap CF, Tan WS, Sieo CC, Tey BT
    Biotechnol Prog, 2013 Mar-Apr;29(2):564-7.
    PMID: 23364925 DOI: 10.1002/btpr.1697
    NP(Δc375) is a truncated version of the nucleocapsid protein of Newcastle disease virus (NDV) which self-assembles into a long helical structure. A packed bed anion exchange chromatography (PB-AEC), SepFastTM Supor Q pre-packed column, was used to purify NP(Δc375) from clarified feedstock. This PB-AEC column adsorbed 76.2% of NP(Δc375) from the clarified feedstock. About 67.5% of the adsorbed NP(Δc375) was successfully eluted from the column by applying 50 mM Tris-HCl elution buffer supplemented with 0.5 M NaCl at pH 7. Thus, a recovery yield of 51.4% with a purity of 76.7% which corresponds to a purification factor of 6.5 was achieved in this PB-AEC operation. Electron microscopic analysis revealed that the helical structure of the NP(Δc375) purified by SepFast(TM) Supor Q pre-packed column was as long as 490 nm and 22-24 nm in diameter. The antigenicity of the purified NP(Δc375) was confirmed by enzyme-linked immunosorbent assay.
    Matched MeSH terms: Escherichia coli/genetics; Escherichia coli/metabolism; Escherichia coli/chemistry*
  3. Fulltext Changes in the Carbon Metabolism of Escherichia coli During the Evolution of Doxycycline Resistance
    Yang Y, Mi J, Liang J, Liao X, Ma B, Zou Y, et al.
    Front Microbiol, 2019;10:2506.
    PMID: 31736928 DOI: 10.3389/fmicb.2019.02506
    Despite our continuous improvement in understanding the evolution of antibiotic resistance, the changes in the carbon metabolism during the evolution of antibiotic resistance remains unclear. To investigate the evolution of antibiotic resistance and the changes in carbon metabolism under antibiotic pressure, Escherichia coli K-12 was evolved for 38 passages under a concentration gradient of doxycycline (DOX). The 0th-passage sensitive strain W0, the 20th-passage moderately resistant strain M20, and the 38th-passage highly resistant strain E38 were selected for the determination of biofilm formation, colony area, and carbon metabolism levels, as well as genome and transcriptome sequencing. The MIC of DOX with E. coli significantly increased from 4 to 96 μg/ml, and the IC50 increased from 2.18 ± 0.08 to 64.79 ± 0.75 μg/ml after 38 passages of domestication. Compared with the sensitive strain W0, the biofilm formation amount of the resistant strains M20 and E38 was significantly increased (p < 0.05). Single-nucleotide polymorphisms (SNPs) were distributed in antibiotic resistance-related genes such as ribosome targets, cell membranes, and multiple efflux pumps. In addition, there were no mutated genes related to carbon metabolism. However, the genes involved in the biosynthesis of secondary metabolites and carbon metabolism pathway were downregulated, showing a significant decrease in the metabolic intensity of 23 carbon sources (p < 0.05). The results presented here show that there may be a correlation between the evolution of E. coli DOX resistance and the decrease of carbon metabolism, and the mechanism was worthy of further research, providing a theoretical basis for the prevention and control of microbial resistance.
    Matched MeSH terms: Escherichia coli; Escherichia coli K12
  4. Antibiofilm activity and mode of action of DMSO alone and its combination with afatinib against Gram-negative pathogens
    Yahya MFZR, Alias Z, Karsani SA
    Folia Microbiol (Praha), 2018 Jan;63(1):23-30.
    PMID: 28540585 DOI: 10.1007/s12223-017-0532-9
    Biofilms are complex microbial communities that tend to attach to either biotic or abiotic surface. Enclosed in a self-produced extracellular polymeric substance (EPS) matrix, the biofilms often cause persistent infections. The objective of this study was to investigate the antibiofilm activity of dimethyl sulfoxide (DMSO) and afatinib against Gram-negative pathogens. Test microorganisms used in this study were Escherichia coli ATCC 1299, Pseudomonas aeruginosa ATCC 10145, and Salmonella typhimurium ATCC 14028. Biofilms were developed in 96-well microplate at 37°C for 24 h. Following removal of non-adherent cells, analysis of biofilm viability, biofilm biomass, and extracellular polymeric substances (EPS) matrix were performed using resazurin assay, crystal violet assay, and attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy, respectively. Bradford protein assay was conducted to determine the total amount of EPS proteins. The results demonstrated that both 32% DMSO alone and its combination with 3.2 μg/mL afatinib were effective in killing biofilm cells and reducing biofilm biomass. IR spectral variations of EPS matrix of biofilms in the range between 1700 and 900 cm-1 were also observed. Reduction in EPS proteins verified the chemical modifications of EPS matrix. In conclusion, 32% DMSO alone and its combination with 3.2 μg/mL afatinib showed remarkable antibiofilm activities against Gram-negative pathogens. It was suggested that the biofilm inhibition was mediated by the chemical modification of EPS matrix.
    Matched MeSH terms: Escherichia coli/drug effects*; Escherichia coli/physiology
  5. Recombinant LipL32 Protein Developed Using a Synthetic Gene Detects Leptospira-specific Antibodies in Human Serum Samples
    Yaakob Y, Rodrigues KF, Opook F, William T, John DV
    Malays J Med Sci, 2017 Oct;24(5):44-51.
    PMID: 29386971 DOI: 10.21315/mjms2017.24.5.5
    Background: Synthetic biology is emerging as a viable alternative for the production of recombinant antigens for diagnostic applications. It offers a safe alternative for the synthesis of antigenic principles derived from organisms that pose a high biological risk.

    Methods: Here, we describe an enzyme-linked immunosorbent assay (ELISA) using the synthetic recombinant LipL32 (rLipL32) protein expressed in Escherichia coli for the detection of Leptospira-specific antibodies in human serum samples. The rLipL32-based ELISA was compared with a microscopic agglutination test (MAT), which is currently used as the gold standard for the diagnosis of leptospirosis.

    Results: Our results showed that all the MAT-positive serum samples were positive for Leptospira-specific IgG in an ELISA, while 65% (n = 13) of these samples were also positive for Leptospira-specific IgM. In the MAT-negative serum samples, 80% and 55% of the samples were detected as negative by an ELISA for Leptospira-specific IgM and IgG, respectively.

    Conclusion: An ELISA using the synthetic rLipL32 antigen was able to distinguish Leptospira-specific IgM (sensitivity 65% and specificity 80%) and IgG (sensitivity 100% and specificity 55%) in human serum samples and has the potential to serve as a rapid diagnostic test for leptospirosis.

    Matched MeSH terms: Escherichia coli
  6. Fulltext The Role of Solvent-Accessible Leu-208 of Cold-Active Pseudomonas fluorescens Strain AMS8 Lipase in Interfacial Activation, Substrate Accessibility and Low-Molecular Weight Esterification in the Presence of Toluene
    Yaacob N, Ahmad Kamarudin NH, Leow ATC, Salleh AB, Raja Abd Rahman RNZ, Mohamad Ali MS
    Molecules, 2017 Aug 12;22(8).
    PMID: 28805665 DOI: 10.3390/molecules22081312
    The alkaline cold-active lipase from Pseudomonas fluorescens AMS8 undergoes major structural changes when reacted with hydrophobic organic solvents. In toluene, the AMS8 lipase catalytic region is exposed by the moving hydrophobic lid 2 (Glu-148 to Gly-167). Solvent-accessible surface area analysis revealed that Leu-208, which is located next to the nucleophilic Ser-207 has a focal function in influencing substrate accessibility and flexibility of the catalytic pocket. Based on molecular dynamic simulations, it was found that Leu-208 strongly facilitates the lid 2 opening via its side-chain. The KM and Kcat/KM of L208A mutant were substrate dependent as it preferred a smaller-chain ester (pNP-caprylate) as compared to medium (pNP-laurate) or long-chain (pNP-palmitate) esters. In esterification of ethyl hexanoate, L208A promotes a higher ester conversion rate at 20 °C but not at 30 °C, as a 27% decline was observed. Interestingly, the wild-type (WT) lipase's conversion rate was found to increase with a higher temperature. WT lipase AMS8 esterification was higher in toluene as compared to L208A. Hence, the results showed that Leu-208 of AMS8 lipase plays an important role in steering a broad range of substrates into its active site region by regulating the flexibility of this region. Leu-208 is therefore predicted to be crucial for its role in interfacial activation and catalysis in toluene.
    Matched MeSH terms: Escherichia coli
  7. Antibacterial efficacy of poly(hexamethylene biguanide) immobilized on chitosan/dye-modified nanofiber membranes
    Xu FX, Ooi CW, Liu BL, Song CP, Chiu CY, Wang CY, et al.
    Int J Biol Macromol, 2021 Jun 30;181:508-520.
    PMID: 33775766 DOI: 10.1016/j.ijbiomac.2021.03.151
    This study aimed to develop a novel electrospun polyacrylonitrile (PAN) nanofiber membrane with the enhanced antibacterial property. The PAN nanofiber membrane was first subjected to alkaline hydrolysis treatment, and the treated membrane was subsequently grafted with chitosan (CS) to obtain a CS-modified nanofiber membrane (P-COOH-CS). The modified membrane was then coupled with different dye molecules to form P-COOH-CS-Dye membranes. Lastly, poly(hexamethylene biguanide) hydrochloride (PHMB) was immobilized on the modified membrane to produce P-COOH-CS-Dye-PHMB. Physical characterization studies were conducted on all the synthesized nanofiber membranes. The antibacterial efficacies of nanofiber membranes prepared under different synthesis conditions were evaluated systematically. Under the optimum synthesis conditions, P-COOH-CS-Dye-PHMB was highly effective in disinfecting a high concentration of Escherichia coli, with an antibacterial efficacy of approximately 100%. Additionally, the P-COOH-CS-Dye-PHMB exhibited an outstanding wash durability as its antibacterial efficacy was only reduced in the range of 5%-7% even after 5 repeated cycles of treatment. Overall, the experimental results of this study suggested that the P-COOH-CS-Dye-PHMB is a promising antibacterial nanofiber membrane that can be adopted in the food, pharmaceutical, and textile industries.
    Matched MeSH terms: Escherichia coli/drug effects
  8. Antibacterial efficacy of quaternized chitosan/poly (vinyl alcohol) nanofiber membrane crosslinked with blocked diisocyanate
    Wu JY, Ooi CW, Song CP, Wang CY, Liu BL, Lin GY, et al.
    Carbohydr Polym, 2021 Jun 15;262:117910.
    PMID: 33838797 DOI: 10.1016/j.carbpol.2021.117910
    N-[(2-hydroxyl-3-trimethylammonium) propyl] chitosan chloride (HTCC), which is a type of chitosan derivative with quaternary ammonium groups, possesses a higher antibacterial activity as compared to the pristine chitosan. The nanofiber membranes made of HTCC are attractive for applications demanding for antibacterial function. However, the hydrophilic nature of HTCC makes it unsuitable for electrospinning of nanofibers. Hence, biodegradable polyvinyl alcohol (PVA) was proposed as an additive to improve the electrospinnability of HTCC. In this work, PVA/HTCC nanofiber membrane was crosslinked with the blocked diisocyanate (BI) to enhance the stability of nanofiber membrane in water. Microbiological assessments showed that the PVA/HTCC/BI nanofiber membranes possessed a good antibacterial efficacy (∼100 %) against E. coli. Moreover, the biocompatibility of PVA/HTCC/BI nanofiber membrane was proven by the cytotoxicity test on mouse fibroblasts. These promising results indicated that the PVA/HTCC/BI nanofiber membrane can be a promising material for food packaging and as a potential wound dressing for skin regeneration.
    Matched MeSH terms: Escherichia coli/drug effects
  9. Silver Nanoparticle Coated Bioactive Glasses--Composites with Dex/CMC Hydrogels: Characterization, Solubility, and In Vitro Biological Studies
    Wren AW, Hassanzadeh P, Placek LM, Keenan TJ, Coughlan A, Boutelle LR, et al.
    Macromol Biosci, 2015 Aug;15(8):1146-58.
    PMID: 25923463 DOI: 10.1002/mabi.201500109
    Silver (Ag) coated bioactive glass particles (Ag-BG) were formulated and compared to uncoated controls (BG) in relation to glass characterization, solubility and microbiology. X-ray diffraction (XRD) confirmed a crystalline AgNP surface coating while ion release studies determined low Ag release (<2 mg/L). Cell culture studies presented increased cell viability (127 and 102%) with lower liquid extract (50 and 100 ml/ml) concentrations. Antibacterial testing of Ag-BG in E. coli, S. epidermidis and S. aureus significantly reduced bacterial cell viability by 60-90%. Composites of Ag-BG/CMC-Dex Hydrogels were formulated and characterized. Agar diffusion testing was conducted where Ag-BG/hydrogel composites produced the largest inhibition zones of 7 mm (E. coli), 5 mm (S. aureus) and 4 mm (S. epidermidis).
    Matched MeSH terms: Escherichia coli/drug effects
  10. Fulltext Antarctic bacteria inhibit the growth of pathogens
    Wong, C.M.V.L., Chung, H.H., Aisyah, S., Omar, S., Cheah, Y.K., Maria de, L.G., et al.
    ASM Science Journal, 2009;3(2):107-112.
    MyJurnal
    There are relatively little data on bacteria with antimicrobial activities from Antarctic, especially from the South Shetland Islands when compared to the other parts of the world. Hence, this project was set to isolate and characterize bacteria that produce anti-microbial compounds from Greenwich Island (one of the South Shetland Islands), Antarctica. A total of 356 strains of bacteria were isolated from Greenwich Island. They were screened for antimicrobial activities against 13 Gram-negative and one Gram-positive indicator food-borne pathogens. Two out of the 356 Antarctic bacterial strains exhibited an antagonistic effect on the indicator strains, Escherichia coli, Salmonella spp., Klebsiella pneumoniae, Enterobacter cloacae, Vibrio parahaemolyticus and Bacillus cereus. The two Antarctic bacterial strains were designated as SS157 and SR13. Biochemical and 16S rDNA analysis indicated that the strain SS157 was closely related to Pseudomonas congelans while the strain SR13 was closely related to Pseudomonas tremae. The anti-microbial compounds produced by the two Antarctic bacteria were not sensitive to temperature and were not degraded by trypsin or pronase indicating that they were likely to be chemical compounds or antibiotics. Antimicrobial compounds from strains SS157 and SR13 were broad spectrum, and targeted both Gram-positive and negative pathogens.
    Matched MeSH terms: Escherichia coli
  11. Phage N15-Based Vectors for Gene Cloning and Expression in Bacteria and Mammalian Cells
    Wong YC, Ng AWR, Chen Q, Liew PS, Lee CW, Sim EUH, et al.
    ACS Synth Biol, 2023 Apr 21;12(4):909-921.
    PMID: 37026178 DOI: 10.1021/acssynbio.2c00580
    Bacteriophage N15 is the first virus known to deliver linear prophage into Escherichia coli. During its lysogenic cycle, N15 protelomerase (TelN) resolves its telomerase occupancy site (tos) into hairpin telomeres. This protects the N15 prophage from bacterial exonuclease degradation, enabling it to stably replicate as a linear plasmid in E. coli. Interestingly, purely proteinaceous TelN can retain phage DNA linearization and hairpin formation without involving host- or phage-derived intermediates or cofactors in the heterologous environment. This unique feature has led to the advent of synthetic linear DNA vector systems derived from the TelN-tos module for the genetic engineering of bacterial and mammalian cells. This review will focus on the development and advantages of N15-based novel cloning and expression vectors in the bacterial and mammalian environments. To date, N15 is the most widely exploited molecular tool for the development of linear vector systems, especially the production of therapeutically useful miniDNA vectors without a bacterial backbone. Compared to typical circular plasmids, linear N15-based plasmids display remarkable cloning fidelity in propagating unstable repetitive DNA sequences and large genomic fragments. Additionally, TelN-linearized vectors with the relevant origin of replication can replicate extrachromosomally and retain transgenes functionality in bacterial and mammalian cells without compromising host cell viability. Currently, this DNA linearization system has shown robust results in the development of gene delivery vehicles, DNA vaccines and engineering mammalian cells against infectious diseases or cancers, highlighting its multifaceted importance in genetic studies and gene medicine.
    Matched MeSH terms: Escherichia coli/metabolism
  12. Immunogenic properties of recombinant ectodomain of Newcastle disease virus hemagglutinin-neuraminidase protein expressed in Escherichia coli
    Wong SK, Tan WS, Omar AR, Tan CS, Yusoff K
    Acta Virol., 2009;53(1):35-41.
    PMID: 19301949
    Hemagglutinin-neuraminidase (HN) protein of Newcastle disease virus (NDV) plays a vital role in the viral infectivity, host immunity, and disease diagnosis. A portion of the HN gene encoding the ectodomain (nt 142-1739) was cloned and expressed in Escherichia coli yielding an insoluble HN protein and a soluble NusA-HN protein containing N-utilization substance A (NusA) fusion component. Both recombinant proteins were purified and used for immunization of chickens. The recombinant HN protein induced higher antibody titers as compared to the recombinant NusA-HN protein. These antibodies were able to react in immunoblot analysis with the corresponding recombinant proteins as well as with the HN protein of NDV.
    Matched MeSH terms: Escherichia coli
  13. Fulltext Structural modeling and biochemical characterization of recombinant KPN_02809, a zinc-dependent metalloprotease from Klebsiella pneumoniae MGH 78578
    Wong MT, Choi SB, Kuan CS, Chua SL, Chang CH, Normi YM, et al.
    Int J Mol Sci, 2012;13(1):901-17.
    PMID: 22312293 DOI: 10.3390/ijms13010901
    Klebsiella pneumoniae is a Gram-negative, cylindrical rod shaped opportunistic pathogen that is found in the environment as well as existing as a normal flora in mammalian mucosal surfaces such as the mouth, skin, and intestines. Clinically it is the most important member of the family of Enterobacteriaceae that causes neonatal sepsis and nosocomial infections. In this work, a combination of protein sequence analysis, structural modeling and molecular docking simulation approaches were employed to provide an understanding of the possible functions and characteristics of a hypothetical protein (KPN_02809) from K. pneumoniae MGH 78578. The computational analyses showed that this protein was a metalloprotease with zinc binding motif, HEXXH. To verify this result, a ypfJ gene which encodes for this hypothetical protein was cloned from K. pneumoniae MGH 78578 and the protein was overexpressed in Escherichia coli BL21 (DE3). The purified protein was about 32 kDa and showed maximum protease activity at 30 °C and pH 8.0. The enzyme activity was inhibited by metalloprotease inhibitors such as EDTA, 1,10-phenanthroline and reducing agent, 1,4-dithiothreitol (DTT). Each molecule of KPN_02809 protein was also shown to bind one zinc ion. Hence, for the first time, we experimentally confirmed that KPN_02809 is an active enzyme with zinc metalloprotease activity.
    Matched MeSH terms: Escherichia coli/metabolism
  14. beta-Lactam resistance phenotype determination in Escherichia coli isolates from University Malaya Medical Centre
    Wong JS, Mohd Azri ZA, Subramaniam G, Ho SE, Palasubramaniam S, Navaratnam P
    Malays J Pathol, 2003 Dec;25(2):113-9.
    PMID: 16196367
    beta-Lactamases have been identified as the major cause of antimicrobial resistance to beta-lactam antibiotics in Escherichia coli. The activities of ampicillin-sulbactam and amoxicillin-clavulanate as well as a range of beta-lactam antibiotics were studied with 87 clinical E. coli isolates from patients of the University Malaya Medical Center using the disc diffusion technique. Susceptible, intermediate and resistant categories were established based on the diameter of zones of inhibition set by the National Committee for Clinical Laboratory Standards (NCCLS). The isolates were then classified into 6 phenotypes according to the criteria stated in the methodology: S (susceptible to all beta-lactams); TL (resistant to aminopenicillins; amoxicillin-clavulanate susceptible and susceptible or intermediate to ampicillin-sulbactam); TI (resistant to aminopenicillins and ampicillin-sulbactam; susceptible to amoxicilin-clavulanate); TH-IRT (resistant to aminopenicillins; intermediate or resistant to amoxicillin-clavulanate; resistant to ampicillin-sulbactam); ESBL (resistant to aminopenicillins and oxyimino cephalosporins; positive results with the double-disc diffusion test); and CP (resistant to aminopenicillins, beta-lactam-beta-lactamase inhibitor combinations, oxyimino cephalosporins and cephamycins). Results showed that the TL phenotype was the commonest (40.2% of the isolates) followed by S (31%), TH-IRT (16.1%), ESBL and CP (3.4% each) and TI (2.3%). One isolate showed both ESBL and CP phenotypes while two isolates were classified as inconclusive. Representatives from each phenotype were further analysed for the presence of beta-lactamases which revealed a predominance of TEM and SHV enzyme producers. PCR-SSCP analysis of the SHV gene from all the ESBL and CP isolates revealed the predominance of SHV 5-type enzyme which was concurrent with our previous studies.
    Matched MeSH terms: Escherichia coli/classification; Escherichia coli/drug effects*; Escherichia coli/enzymology; Escherichia coli/genetics
  15. Cephalhematoma infected by Escherichia coli presenting as an extensive scalp abscess
    Wong CS, Cheah FC
    J Pediatr Surg, 2012 Dec;47(12):2336-40.
    PMID: 23217901 DOI: 10.1016/j.jpedsurg.2012.09.029
    Cephalhematoma is normally a self-limiting condition affecting 1%-2% of live births, especially following instrumental forceps delivery. The sub-periosteal bleed is characteristically limited by the cranial sutures. Although benign in most instances, this condition may, in a small proportion of cases, be complicated by hyperbilirubinemia or scalp infection. We describe a case of cephalhematoma in a newborn infant infected with Escherichia coli resulting in an extensive deep seated scalp abscess. The infection was also systemic causing E. coli septicemia and initial assessment assumed local extension including bone and meningeal to cause skull osteomyelitis and meningitis respectively. Further investigations and multiple-modality imaging with ultrasound, CT scan and bone scintigraphy outlined the involvement as limited to the scalp, resulting in a shorter antibiotic treatment period and earlier discharge from hospital. The infant recovered well with parenteral antibiotics, saucerization of the abscess and a later skin grafting procedure.
    Matched MeSH terms: Escherichia coli/isolation & purification; Escherichia coli Infections/diagnosis; Escherichia coli Infections/microbiology*; Escherichia coli Infections/therapy
  16. Organic-solvent stability of elastase strain K overexpressed in an Escherichia-Pseudomonas expression system
    Wong CF, Salleh AB, Basri M, Abd Rahman RN
    Biotechnol Appl Biochem, 2010 Sep;57(1):1-7.
    PMID: 20726840 DOI: 10.1042/BA20100224
    The structural gene of elastase strain K (elastase from Pseudomonas aeruginosa strain K), namely HindIII1500PstI, was successfully sequenced to contain 1497 bp. The amino acid sequence, deduced from the nucleotide sequence, revealed that the mature elastase consists of 301 amino acids, with a molecular mass of 33.1 kDa, and contains a conserved motif HEXXH, zinc ligands and residues involved in the catalysis of elastase strain K. The structural gene was successfully cloned to a shuttle vector, pUCP19, and transformed into Escherichia coli strains TOP10, KRX, JM109 and Tuner™ pLacI as well as P. aeruginosa strains PA01 (A.T.C.C. 47085) and S5, with detection of significant protein expression. Overexpression was detected from transformants KRX/pUCP19/HindIII1500PstI of E. coli and PA01/pUCP19/HindIII1500PstI of P. aeruginosa, with increases in elastolytic activity to 13.83- and 5.04-fold respectively relative to their controls. In addition, recombinant elastase strain K showed considerable stability towards numerous organic solvents such as methanol, ethanol, acetone, toluene, undecan-1-ol and n-dodecane, which typically pose a detrimental effect on enzymes; our finding provides further information to support the potential application of the enzyme in synthetic industries, particularly peptide synthesis.
    Matched MeSH terms: Escherichia coli/genetics; Escherichia coli/metabolism*
  17. Fulltext Construction of New Genetic Tools as Alternatives for Protein Overexpression in Escherichia coli and Pseudomonas aeruginosa
    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: Escherichia coli
  18. Fulltext Neonatal bartter syndrome
    Wong AC, Chan LG
    Med J Malaysia, 2014 Oct;69(5):229-30.
    PMID: 25638238 MyJurnal
    We report a case of neonatal Bartter syndrome in a 31 weeks premature baby girl with antenatal unexplained polyhydramnios requiring amnioreduction. She presented with early onset E. coli septicaemia and severe dehydration leading to pre-renal renal impairment which obscure the typical biochemical changes of hypokalaemic hypochloraemic metabolic alkalosis.
    Matched MeSH terms: Escherichia coli; Escherichia coli Infections
  19. Insensitivity of bacterial nucleic acid biosyntheses to a morphine-like narcotic
    Wolfe AD, Hahn FE
    Naturwissenschaften, 1975 Feb;62(2):99.
    PMID: 1683
    Matched MeSH terms: Escherichia coli/drug effects*; Escherichia coli/metabolism
  20. Identification of Antibacterial Molecule(s) from Animals Living in Polluted Environments
    Winnie FYM, Siddiqui R, Sagathevan K, Khan NA
    Curr Pharm Biotechnol, 2020;21(5):425-437.
    PMID: 31577204 DOI: 10.2174/1389201020666191002153435
    BACKGROUND: Snakes feed on germ-infested rodents, while water monitor lizards thrive on rotten matter in unhygienic conditions. We hypothesize that such creatures survive the assault of superbugs and are able to fend off disease by producing antimicrobial substances. In this study, we investigated the potential antibacterial activity of sera/lysates of animals living in polluted environments.

    METHODS: Snake (Reticulatus malayanus), rats (Rattus rattus), water monitor lizard (Varanus salvator), frog (Lithobates catesbeianus), fish (Oreochromis mossambicus), chicken (Gallus gallus domesticus), and pigeon (Columba livia) were dissected and their organ lysates/sera were collected. Crude extracts were tested for bactericidal effects against neuropathogenic E. coli K1, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Pseudomonas aeruginosa, Bacillus cereus and Klebsiella pneumoniae. To determine whether lysates/sera protect human cells against bacterialmediated damage, cytotoxicity assays were performed by measuring lactate dehydrogenase release as an indicator of cell death. Lysates/sera were partially characterized using heat-treatment and pronasetreatment and peptide sequences were determined using the Liquid Chromatography Mass Spectrometry (LC-MS).

    RESULTS: Snake and water monitor lizard sera exhibited potent broad-spectrum bactericidal effects against all bacteria tested. Heat inactivation and pronase-treatment inhibited bactericidal effects indicating that activity is heat-labile and pronase-sensitive suggesting that active molecules are proteinaceous in nature. LCMS analyses revealed the molecular identities of peptides.

    CONCLUSION: The results revealed that python that feeds on germ-infested rodents and water monitor lizards that feed on rotten organic waste possess antibacterial activity in a heat-sensitive manner and several peptides were identified. We hope that the discovery of antibacterial activity in the sera of animals living in polluted environments will stimulate research in finding antibacterial agents from unusual sources as this has the potential for the development of novel strategies in the control of infectious diseases.

    Matched MeSH terms: Escherichia coli/drug effects
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