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  1. Fulltext scFv antibody: principles and clinical application
    Ahmad ZA, Yeap SK, Ali AM, Ho WY, Alitheen NB, Hamid M
    Clin. Dev. Immunol., 2012;2012:980250.
    PMID: 22474489 DOI: 10.1155/2012/980250
    To date, generation of single-chain fragment variable (scFv) has become an established technique used to produce a completely functional antigen-binding fragment in bacterial systems. The advances in antibody engineering have now facilitated a more efficient and generally applicable method to produce Fv fragments. Basically, scFv antibodies produced from phage display can be genetically fused to the marker proteins, such as fluorescent proteins or alkaline phosphatase. These bifunctional proteins having both antigen-binding capacity and marker activity can be obtained from transformed bacteria and used for one-step immunodetection of biological agents. Alternatively, antibody fragments could also be applied in the construction of immunotoxins, therapeutic gene delivery, and anticancer intrabodies for therapeutic purposes. This paper provides an overview of the current studies on the principle, generation, and application of scFv. The potential of scFv in breast cancer research is also discussed in this paper.
    Matched MeSH terms: Escherichia coli
  2. 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
  3. Fulltext Zinc oxide from aloe vera extract: two-level factorial screening of biosynthesis parameters
    Rasli NI, Basri H, Harun Z
    Heliyon, 2020 Jan;6(1):e03156.
    PMID: 32042952 DOI: 10.1016/j.heliyon.2020.e03156
    Zinc oxide (ZnO) was biosynthesised from aloe vera plant extract. The aloe vera plant extract was used as a reducing agent in biosynthesis process. Green synthesis method was proposed because it is cost effective and environmentally friendly. ZnO was characterised using SEM, EDX, FTIR, and XRD analyses. The antibacterial property was tested against Escherichia coli. The effects of aloe vera volume (2-50) mL, precursor concentration (0.001-0.300) M, reaction time (20 min-48 h), and temperature of the reaction (26-200) °C on ZnO characteristics were investigated and screened using a two-level factorial method. Based on the observation and ANOVA analysis result, precursor concentration was the only significant parameter that affected the production of the ZnO nanoparticles (NPs). The EDX analysis proved the presence of ZnO while the SEM analysis confirmed the average size of ZnO particle size was in the range of (18-618) μm with a rod-shape appearance. The XRD analysis showed that the average crystallite size was 0.452 μm and it was in the hexagonal phase. It was also proven to have antibacterial property against E. coli.
    Matched MeSH terms: Escherichia coli
  4. Zerumbone from Zingiber zerumbet inhibits innate and adaptive immune responses in Balb/C mice
    Jantan I, Haque MA, Ilangkovan M, Arshad L
    Int Immunopharmacol, 2019 Aug;73:552-559.
    PMID: 31177081 DOI: 10.1016/j.intimp.2019.05.035
    Zerumbone exhibited various biological properties including in vitro immunosuppressive effects. However, its modulatory activity on the immune responses in experimental animal model is largely unknown. This investigation was conducted to explore the effects of daily treatment of zerumbone (25, 50, and 100 mg/kg) isolated from Zingiber zerumbet rhizomes for 14 days on various cellular and humoral immune responses in Balb/C mice. For measurement of adaptive immunity, sheep red blood cells (sRBC) were used to immunize the mice on day 0 and orally fed with similar doses of zerumbone for 14 days. The effects of zerumbone on phagocytosis, nitric oxide (NO) release, myeloperoxidase (MPO) activity, proliferation of T and B cells, lymphocyte phenotyping, cytokines release in serum by activated T cells, delayed type hypersensitivity (DTH) and immunoglobulins production (IgG and IgM) were investigated. Zerumbone downregulated the engulfment of E. coli by peritoneal macrophages and the release of NO and MPO in a concentration-dependent manner. Zerumbone showed significant and concentration-dependent suppression of T and B lymphocytes proliferation and inhibition of the Th1 and Th2 cytokines release. At higher concentrations of zerumbone, the % expression of CD4+ and CD8+ in splenocytes was significantly inhibited. Zerumbone also concentration-dependently demonstrated strong suppression on sRBC-triggered swelling of mice paw in DTH. Substantial suppression of anti-sRBC immunoglobulins antibody titer was noted in immunized and zerumbone-treated mice in a concentration-dependent manner. The potent suppressive effects of zerumbone on the immune responses suggest that zerumbone can be a potential candidate for development of immunosuppressive agent.
    Matched MeSH terms: Escherichia coli
  5. Wound dressings functionalized with silver nanoparticles: promises and pitfalls
    Kalantari K, Mostafavi E, Afifi AM, Izadiyan Z, Jahangirian H, Rafiee-Moghaddam R, et al.
    Nanoscale, 2020 Jan 28;12(4):2268-2291.
    PMID: 31942896 DOI: 10.1039/c9nr08234d
    Infections are the main reason why most people die from burns and diabetic wounds. The clinical challenge for treating wound infections through traditional antibiotics has been growing steadily and has now reached a critical status requiring a paradigm shift for improved chronic wound care. The US Centers for Disease Control have predicted more deaths from antimicrobial-resistant bacteria than from all types of cancers combined by 2050. Thus, the development of new wound dressing materials that do not rely on antibiotics is of paramount importance. Currently, incorporating nanoparticles into scaffolds represents a new concept of 'nanoparticle dressing' which has gained considerable attention for wound healing. Silver nanoparticles (Ag-NPs) have been categorized as metal-based nanoparticles and are intriguing materials for wound healing because of their excellent antimicrobial properties. Ag-NPs embedded in wound dressing polymers promote wound healing and control microorganism growth. However, there have been several recent disadvantages of using Ag-NPs to fight infections, such as bacterial resistance. This review highlights the therapeutic approaches of using wound dressings functionalized with Ag-NPs and their potential role in revolutionizing wound healing. Moreover, the physiology of the skin and wounds is discussed to place the use of Ag-NPs in wound care into perspective.
    Matched MeSH terms: Escherichia coli
  6. Fulltext Whole-Genome Sequence of Endophytic Plant Growth-Promoting Escherichia coli USML2
    Tharek M, Sim KS, Khairuddin D, Ghazali AH, Najimudin N
    Genome Announc, 2017 May 11;5(19).
    PMID: 28495774 DOI: 10.1128/genomeA.00305-17
    Escherichia coli strain USML2 was originally isolated from the inner leaf tissues of surface-sterilized phytopathogenic-free oil palm (Elaeis guineensis Jacq.). We present here the whole-genome sequence of this plant-endophytic strain. The genome consists of a single circular chromosome of 4,502,758 bp, 4,315 predicted coding sequences, and a G+C content of 50.8%.
    Matched MeSH terms: Escherichia coli
  7. Fulltext Whole genome sequencing enables the characterization of BurI, a LuxI homologue of Burkholderia cepacia strain GG4
    How KY, Hong KW, Chan KG
    PeerJ, 2015;3:e1117.
    PMID: 26290785 DOI: 10.7717/peerj.1117
    Quorum sensing is a mechanism for regulating proteobacterial gene expression in response to changes in cell population. In proteobacteria, N-acyl homoserine lactone (AHL) appears to be the most widely used signalling molecules in mediating, among others, the production of extracellular virulence factors for survival. In this work, the genome of B. cepacia strain GG4, a plasmid-free strain capable of AHL synthesis was explored. In silico analysis of the 6.6 Mb complete genome revealed the presence of a LuxI homologue which correspond to Type I quorum sensing. Here, we report the molecular cloning and characterization of this LuxI homologue, designated as BurI. This 609 bp gene was cloned and overexpressed in Escherichia coli BL21(DE3). The purified protein was approximately 25 kDa and is highly similar to several autoinducer proteins of the LuxI family among Burkholderia species. To verify the AHL synthesis activity of this protein, high resolution liquid chromatography-mass spectrometry analysis revealed the production of 3-oxo-hexanoylhomoserine lactone, N-octanoylhomoserine lactone and 3-hydroxy-octanoylhomoserine lactone from induced E. coli BL21 harboring the recombinant BurI. Our data show, for the first time, the cloning and characterization of the LuxI homologue from B. cepacia strain GG4 and confirmation of its AHL synthesis activity.
    Matched MeSH terms: Escherichia coli
  8. Virus-like particles of Macrobrachium rosenbergii nodavirus produced in bacteria
    Goh ZH, Tan SG, Bhassu S, Tan WS
    J Virol Methods, 2011 Jul;175(1):74-9.
    PMID: 21536072 DOI: 10.1016/j.jviromet.2011.04.021
    Macrobrachium rosenbergii nodavirus (MrNv) infects giant freshwater prawns and causes white tail disease (WTD). The coding region of the capsid protein of MrNv was amplified with RT-PCR and cloned into the pTrcHis2-TOPO vector. The recombinant plasmid was introduced into Escherichia coli and protein expression was induced with IPTG. SDS-PAGE showed that the recombinant protein containing the His-tag and myc epitope has a molecular mass of about 46 kDa and it was detected by the anti-His antibody in Western blotting. The protein was purified using immobilized metal affinity chromatography (IMAC) and transmission electron microscopic analysis revealed that the recombinant protein assembled into virus-like particles (VLPs) with a diameter of about 30±3 nm. The size of the particles was confirmed by dynamic light scattering. Nucleic acids were extracted from the VLPs and treatment with nucleases showed that they were mainly RNA molecules. This is the first report describing the production of MrNv capsid protein in bacteria and its assembly into VLPs.
    Matched MeSH terms: Escherichia coli/virology*
  9. Virus-like particle of Macrobrachium rosenbergii nodavirus produced in Spodoptera frugiperda (Sf9) cells is distinctive from that produced in Escherichia coli
    Kueh CL, Yong CY, Masoomi Dezfooli S, Bhassu S, Tan SG, Tan WS
    Biotechnol Prog, 2017 Mar;33(2):549-557.
    PMID: 27860432 DOI: 10.1002/btpr.2409
    Macrobrachium rosenbergii nodavirus (MrNV) is a virus native to giant freshwater prawn. Recombinant MrNV capsid protein has been produced in Escherichia coli, which self-assembled into virus-like particles (VLPs). However, this recombinant protein is unstable, degrading and forming heterogenous VLPs. In this study, MrNV capsid protein was produced in insect Spodoptera frugiperda (Sf9) cells through a baculovirus system. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed that the recombinant protein produced by the insect cells self-assembled into highly stable, homogenous VLPs each of approximately 40 nm in diameter. Enzyme-linked immunosorbent assay (ELISA) showed that the VLPs produced in Sf9 cells were highly antigenic and comparable to those produced in E. coli. In addition, the Sf9 produced VLPs were highly stable across a wide pH range (2-12). Interestingly, the Sf9 produced VLPs contained DNA of approximately 48 kilo base pairs and RNA molecules. This study is the first report on the production and characterization of MrNV VLPs produced in a eukaryotic system. The MrNV VLPs produced in Sf9 cells were about 10 nm bigger and had a uniform morphology compared with the VLPs produced in E. coli. The insect cell production system provides a good source of MrNV VLPs for structural and immunological studies as well as for host-pathogen interaction studies. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:549-557, 2017.
    Matched MeSH terms: Escherichia coli/genetics; Escherichia coli/metabolism*
  10. Fulltext Use of FabV-Triclosan Plasmid Selection System for Efficient Expression and Production of Recombinant Proteins in Escherichia coli
    Ali SA, Chew YW, Omar TC, Azman N
    PLoS One, 2015;10(12):e0144189.
    PMID: 26642325 DOI: 10.1371/journal.pone.0144189
    Maintenance of recombinant plasmid vectors in host bacteria relies on the presence of selection antibiotics in the growth media to suppress plasmid -free segregants. However, presence of antibiotic resistance genes and antibiotics themselves is not acceptable in several applications of biotechnology. Previously, we have shown that FabV-Triclosan selection system can be used to select high and medium copy number plasmid vectors in E. coli. Here, we have extended our previous work and demonstrated that expression vectors containing FabV can be used efficiently to express heterologous recombinant proteins in similar or better amounts in E. coli host when compared with expression vectors containing β-lactamase. Use of small amount of non-antibiotic Triclosan as selection agent in growth medium, enhanced plasmid stability, applicability in various culture media, and compatibility with other selection systems for multiple plasmid maintenance are noteworthy features of FabV-Triclosan selection system.
    Matched MeSH terms: Escherichia coli/genetics*; Escherichia coli/metabolism*; Escherichia coli Proteins/genetics; Escherichia coli Proteins/metabolism*
  11. Fulltext Urinary tract infections in pregnancy
    Loh KY, Sivalingam N
    Malays Fam Physician, 2007;2(2):54-57.
    MyJurnal
    Urinary tract infections frequently affect pregnant mothers. This problem causes significant morbidity and healthcare expenditure. Three common clinical manifestations of UTIs in pregnancy are: asymptomatic bacteriuria, acute cystitis and acute pyelonephritis. Escherichia coli remains the most frequent organism isolated in UTIs. All pregnant mothers should be screened for UTIs in pregnancy and antibiotics should be commenced without delay. Urine culture and sensitivity is the gold standard in diagnosing UTIs. Without treatment, asymptomatic bacteriuria in pregnancy is associated with preterm delivery, intrauterine growth retardation, low birth weight, maternal hypertension, pre-eclampsia and anaemia. Acute pyelonephritis can lead to maternal sepsis. Recurrent UTIs in pregnancy require prophylactic antibiotic treatment.
    Matched MeSH terms: Escherichia coli
  12. Fulltext Urinary Tract Infection among Renal Transplant Recipients in Yemen
    Gondos AS, Al-Moyed KA, Al-Robasi AB, Al-Shamahy HA, Alyousefi NA
    PLoS One, 2015;10(12):e0144266.
    PMID: 26657128 DOI: 10.1371/journal.pone.0144266
    Urinary tract infection (UTI) is the most common complication following kidney transplantation (KT), which could result in losing the graft. This study aims to identify the prevalence of bacterial UTI among KT recipients in Yemen and to determine the predisposing factors associated with post renal transplantation UTI. A cross sectional study included of 150 patients, who underwent KT was conducted between June 2010 and January 2011. A Morning mid-stream urine specimen was collected for culture and antibiotic susceptibility test from each recipient. Bacterial UTI was found in 50 patients (33.3%). The prevalence among females 40.3% was higher than males 29%. The UTI was higher in the age group between 41-50 years with a percentage of 28% and this result was statistically significant. Predisposing factors as diabetes mellitus, vesicoureteral reflux, neurogenic bladder and polycystic kidney showed significant association. High relative risks were found for polycystic kidney = 13.5 and neurogenic bladder = 13.5. The most prevalent bacteria to cause UTI was Escherichia coli represent 44%, followed by Staphylococcus saprophyticus 34%. Amikacin was the most effective antibiotic against gram-negative isolates while Ciprofloxacin was the most effective antibiotic against Staphylococcus saprophyticus. In conclusion, there is high prevalence of bacterial UTI among KT recipients in Yemen. Diabetes mellitus, vesicoureteral reflux, neurogenic bladder, polycystic kidney and calculi were the main predisposing factors.
    Matched MeSH terms: Escherichia coli/drug effects; Escherichia coli/isolation & purification
  13. Fulltext Unravelling the genome of long chain N-acylhomoserine lactone-producing Acinetobacter sp. strain GG2 and identification of its quorum sensing synthase gene
    How KY, Hong KW, Sam CK, Koh CL, Yin WF, Chan KG
    Front Microbiol, 2015;6:240.
    PMID: 25926817 DOI: 10.3389/fmicb.2015.00240
    Myriad proteobacteria use N-acyl homoserine lactone (AHL) molecules as quorum sensing (QS) signals to regulate different physiological functions, including virulence, antibiotic production, and biofilm formation. Many of these proteobacteria possess LuxI/LuxR system as the QS mechanism. Recently, we reported the 3.89 Mb genome of Acinetobacter sp. strain GG2. In this work, the genome of this long chain AHL-producing bacterium was unravelled which led to the molecular characterization of luxI homologue, designated as aciI. This 552 bp gene was cloned and overexpressed in Escherichia coli BL21(DE3). The purified protein was ∼20.5 kDa and is highly similar to several autoinducer proteins of LuxI family among Acinetobacter species. To verify the AHL synthesis activity of this protein, high-resolution liquid chromatography-mass spectrometry analysis revealed the production of 3-oxo-dodecanoyl-homoserine lactone and 3-hydroxy-dodecanoyl-homoserine lactone from induced E. coli harboring the recombinant AciI. Our data show for the first time, the cloning and characterization of the luxI homologue from Acinetobacter sp. strain GG2, and confirmation of its AHLs production. These data are of great significance as the annotated genome of strain GG2 has provided a valuable insight in the study of autoinducer molecules and its roles in QS mechanism of the bacterium.
    Matched MeSH terms: Escherichia coli
  14. Fulltext Understanding the NaCl-dependent behavior of hydrogen production of a marine bacterium, Vibrio tritonius
    Al-Saari N, Amada E, Matsumura Y, Tanaka M, Mino S, Sawabe T
    PeerJ, 2019;7:e6769.
    PMID: 31024772 DOI: 10.7717/peerj.6769
    Biohydrogen is one of the most suitable clean energy sources for sustaining a fossil fuel independent society. The use of both land and ocean bioresources as feedstocks show great potential in maximizing biohydrogen production, but sodium ion is one of the main obstacles in efficient bacterial biohydrogen production. Vibrio tritonius strain AM2 can perform efficient hydrogen production with a molar yield of 1.7 mol H2/mol mannitol, which corresponds to 85% theoretical molar yield of H2 production, under saline conditions. With a view to maximizing the hydrogen production using marine biomass, it is important to accumulate knowledge on the effects of salts on the hydrogen production kinetics. Here, we show the kinetics in batch hydrogen production of V. tritonius strain AM2 to investigate the response to various NaCl concentrations. The modified Han-Levenspiel model reveals that salt inhibition in hydrogen production using V. tritonius starts precisely at the point where 10.2 g/L of NaCl is added, and is critically inhibited at 46 g/L. NaCl concentration greatly affects the substrate consumption which in turn affects both growth and hydrogen production. The NaCl-dependent behavior of fermentative hydrogen production of V. tritonius compared to that of Escherichia coli JCM 1649 reveals the marine-adapted fermentative hydrogen production system in V. tritonius. V. tritonius AM2 is capable of producing hydrogen from seaweed carbohydrate under a wide range of NaCl concentrations (5 to 46 g/L). The optimal salt concentration producing the highest levels of hydrogen, optimal substrate consumption and highest molar hydrogen yield is at 10 g/L NaCl (1.0% (w/v)).
    Matched MeSH terms: Escherichia coli
  15. Fulltext Transcriptome analysis of Escherichia coli K1 after therapy with hesperidin conjugated with silver nanoparticles
    Masri A, Khan NA, Zoqratt MZHM, Ayub Q, Anwar A, Rao K, et al.
    BMC Microbiol, 2021 Feb 17;21(1):51.
    PMID: 33596837 DOI: 10.1186/s12866-021-02097-2
    BACKGROUNDS: Escherichia coli K1 causes neonatal meningitis. Transcriptome studies are indispensable to comprehend the pathology and biology of these bacteria. Recently, we showed that nanoparticles loaded with Hesperidin are potential novel antibacterial agents against E. coli K1. Here, bacteria were treated with and without Hesperidin conjugated with silver nanoparticles, and silver alone, and 50% minimum inhibitory concentration was determined. Differential gene expression analysis using RNA-seq, was performed using Degust software and a set of genes involved in cell stress response and metabolism were selected for the study.

    RESULTS: 50% minimum inhibitory concentration with silver-conjugated Hesperidin was achieved with 0.5 μg/ml of Hesperidin conjugated with silver nanoparticles at 1 h. Differential genetic analysis revealed the expression of 122 genes (≥ 2-log FC, P

    Matched MeSH terms: Escherichia coli
  16. Fulltext Transcriptome Analysis of Pseudomonas aeruginosa Biofilm Following the Exposure to Malaysian Stingless Bee Honey
    Seder N, Abu Bakar MH, Abu Rayyan WS
    Adv Appl Bioinform Chem, 2021;14:1-11.
    PMID: 33488102 DOI: 10.2147/AABC.S292143
    Introduction: Malaysian stingless bee honey (Trigona) has been aroused as a potential antimicrobial compound with antibiofilm activity. The capability of the gram-negative bacillus P. aeruginosa to sustain a fatal infection is encoded in the bacterium genome.

    Methods: In the current study, a transcriptome investigation was performed to explore the mechanism underlying the biofilm dispersal of P. aeruginosa after the exposure to Trigona honey.

    Results: Microarray analysis of the Pseudomonas biofilm treated by 20% Trigona honey has revealed a down-regulation of 3478 genes among the 6085 screened genes. Specifically, around 13.5% of the down-regulated genes were biofilm-associated genes. The mapping of the biofilm-associated pathways has shown an ultimate decrease in the expression levels of the D-GMP signaling pathway and diguanylate cyclases (DGCs) genes responsible for c-di-GMP formation.

    Conclusion: We predominantly report the lowering of c-di-GMP through the down-regulation of DGC genes as the main mechanism of biofilm inhibition by Trigona honey.

    Matched MeSH terms: Escherichia coli Proteins
  17. Fulltext Tracking the virus-like particles of Macrobrachium rosenbergii nodavirus in insect cells
    Hanapi UF, Yong CY, Goh ZH, Alitheen NB, Yeap SK, Tan WS
    PeerJ, 2017;5:e2947.
    PMID: 28194311 DOI: 10.7717/peerj.2947
    Macrobrachium rosenbergii nodavirus (MrNv) poses a major threat to the prawn industry. Currently, no effective vaccine and treatment are available to prevent the spread of MrNv. Its infection mechanism and localisation in a host cell are also not well characterised. The MrNv capsid protein (MrNvc) produced in Escherichia coli self-assembled into virus-like particles (VLPs) resembling the native virus. Thus, fluorescein labelled MrNvc VLPs were employed as a model to study the virus entry and localisation in Spodoptera frugiperda, Sf9 cells. Through fluorescence microscopy and sub-cellular fractionation, the MrNvc was shown to enter Sf9 cells, and eventually arrived at the nucleus. The presence of MrNvc within the cytoplasm and nucleus of Sf9 cells was further confirmed by the Z-stack imaging. The presence of ammonium chloride (NH4Cl), genistein, methyl-β-cyclodextrin or chlorpromazine (CPZ) inhibited the entry of MrNvc into Sf9 cells, but cytochalasin D did not inhibit this process. This suggests that the internalisation of MrNvc VLPs is facilitated by caveolae- and clathrin-mediated endocytosis. The whole internalisation process of MrNvc VLPs into a Sf9 cell was recorded with live cell imaging. We have also identified a potential nuclear localisation signal (NLS) of MrNvc through deletion mutagenesis and verified by classical-NLS mapping. Overall, this study provides an insight into the journey of MrNvc VLPs in insect cells.
    Matched MeSH terms: Escherichia coli
  18. Toxin-antitoxin Systems: Classification, Biological Function and Application in Biotechnology
    Ghafourian S, Raftari M, Sadeghifard N, Sekawi Z
    Curr Issues Mol Biol, 2014;16:9-14.
    PMID: 23652423
    The toxin-antitoxin (TA) systems are systems in which an unstable antitoxin inhibits a stable toxin. This review aims to introduce the TA system and its biological application in bacteria. For this purpose, first we introduce a new classification for the TA systems based on how the antitoxin can neutralize the toxin, we then describe the functions of TA systems and finally review the application of these systems in biotechnology.
    Matched MeSH terms: Escherichia coli/genetics; Escherichia coli/metabolism
  19. Toxicity assessment of reduced graphene oxide and titanium dioxide nanomaterials on gram-positive and gram-negative bacteria under normal laboratory lighting condition
    Ahmad NS, Abdullah N, Yasin FM
    Toxicol Rep, 2020;7:693-699.
    PMID: 32528857 DOI: 10.1016/j.toxrep.2020.04.015
    Toxicity effect of reduced graphene oxide (rGO) and titanium dioxide (TiO2) nanomaterials (NMs) on Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria was assessed. For both strains, study demonstrated that the toxicity was time and concentration dependent which led to reduction in growth rate and cell death. Upon NMs exposure, an instantaneous cell death in E. coli culture was observed. This is in contrast with B. subtilis, in which the culture growth remained in the log phase; however their growth rate constant,

    μ
    g

    was reduced by ∼70%. The discrepancy between E. coli and B. subtilis was due to strain-specific response upon contact with NMs. TEM, SEM and EDX analysis revealed direct physical surface-surface interaction, as evidence from the adherence of NMs on the cell surface.
    Matched MeSH terms: Escherichia coli
  20. Total coliforms, arsenic and cadmium exposure through drinking water in the Western Region of Ghana: application of multivariate statistical technique to groundwater quality
    Affum AO, Osae SD, Nyarko BJ, Afful S, Fianko JR, Akiti TT, et al.
    Environ Monit Assess, 2015 Feb;187(2):1.
    PMID: 25600401 DOI: 10.1007/s10661-014-4167-x
    In recent times, surface water resource in the Western Region of Ghana has been found to be inadequate in supply and polluted by various anthropogenic activities. As a result of these problems, the demand for groundwater by the human populations in the peri-urban communities for domestic, municipal and irrigation purposes has increased without prior knowledge of its water quality. Water samples were collected from 14 public hand-dug wells during the rainy season in 2013 and investigated for total coliforms, Escherichia coli, mercury (Hg), arsenic (As), cadmium (Cd) and physicochemical parameters. Multivariate statistical analysis of the dataset and a linear stoichiometric plot of major ions were applied to group the water samples and to identify the main factors and sources of contamination. Hierarchal cluster analysis revealed four clusters from the hydrochemical variables (R-mode) and three clusters in the case of water samples (Q-mode) after z score standardization. Principal component analysis after a varimax rotation of the dataset indicated that the four factors extracted explained 93.3 % of the total variance, which highlighted salinity, toxic elements and hardness pollution as the dominant factors affecting groundwater quality. Cation exchange, mineral dissolution and silicate weathering influenced groundwater quality. The ranking order of major ions was Na(+) > Ca(2+) > K(+) > Mg(2+) and Cl(-) > SO4 (2-) > HCO3 (-). Based on piper plot and the hydrogeology of the study area, sodium chloride (86 %), sodium hydrogen carbonate and sodium carbonate (14 %) water types were identified. Although E. coli were absent in the water samples, 36 % of the wells contained total coliforms (Enterobacter species) which exceeded the WHO guidelines limit of zero colony-forming unit (CFU)/100 mL of drinking water. With the exception of Hg, the concentration of As and Cd in 79 and 43 % of the water samples exceeded the WHO guideline limits of 10 and 3 μg/L for drinking water, respectively. Reported values in some areas in Nigeria, Malaysia and USA indicated that the maximum concentration of Cd was low and As was high in this study. Health risk assessment of Cd, As and Hg based on average daily dose, hazard quotient and cancer risk was determined. In conclusion, multiple natural processes and anthropogenic activities from non-point sources contributed significantly to groundwater salinization, hardness, toxic element and microbiological contamination of the study area. The outcome of this study can be used as a baseline data to prioritize areas for future sustainable development of public wells.
    Matched MeSH terms: Escherichia coli/growth & development
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