Displaying publications 561 - 580 of 837 in total

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  1. Degradation of 5,5-diphenylhydantoin by chlorination and UV/chlorination: kinetics, transformation by-products, and toxicity assessment
    Mansor NA, Tay KS
    Environ Sci Pollut Res Int, 2017 Oct;24(28):22361-22370.
    PMID: 28801887 DOI: 10.1007/s11356-017-9892-6
    This study investigated the reaction kinetics and mechanism of the degradation of 5,5-diphenylhydantoin (DPH) during conventional chlorination and UV/chlorination. DPH is one of the antiepileptic drugs, which has frequently been detected in the aquatic environment. For chlorination, the second-order rate constant for the reaction between DPH and free active chlorine (FAC) was determined at pH 5 to 8. At pH 6 to 8, the efficiency of chlorination in the removal of DPH was found to be dominated by the reaction involving hypochlorous acid (HOCl). The result also showed that anionic species of DPH was more reactive toward FAC as compared with neutral DPH. For UV/chlorination, the effect of FAC dosage and pH on the degradation of DPH was evaluated. UV/chlorination is a more effective method for removing DPH as compared with conventional chlorination and UV irradiation. The DPH degradation rate was found to increase with increasing FAC concentration. On the other hand, the degradation of DPH was found to be more favorable under the acidic condition. Based on the identified transformation by-products, DPH was found to be degraded through the reaction at imidazolidine-2,4-dione moiety of DPH for both chlorination and UV/chlorination. Toxicity study on the chlorination and UV/chlorination-treated DPH solutions suggested that UV/chlorination is a more efficient method for reducing the toxicity of DPH.
    Matched MeSH terms: Escherichia coli/drug effects
  2. Fulltext Crystallization and preliminary X-ray analysis of recombinant Glomerella cingulata cutinase
    Nyon MP, Rice DW, Berrisford JM, Huang H, Moir AJ, Craven CJ, et al.
    Acta Crystallogr Sect F Struct Biol Cryst Commun, 2008 Jun 01;64(Pt 6):504-8.
    PMID: 18540061 DOI: 10.1107/S1744309108012086
    Cutinase catalyzes the hydrolysis of water-soluble esters and long-chain triglycerides and belongs to the family of serine hydrolases. The enzyme is thought to represent an evolutionary link between the esterase and lipase families and has potential applications in a wide range of industrial hydrolytic processes, for which an understanding of the molecular basis of its substrate specificity is critical. Glomerella cingulata cutinase has been cloned and the protein has been overexpressed in Escherichia coli, purified and subsequently crystallized in a wide range of different crystal forms in the presence and absence of inhibitors. The best crystals are those of the apo cutinase, which diffract to beyond 1.6 A resolution and belong to space group P4(1)2(1)2 or P4(3)2(1)2. Crystals of cutinase with the inhibitors PETFP or E600 belong to space groups P2(1)2(1)2(1) and P2(1), respectively, and diffract to approximately 2.5 A resolution. All of the crystals are suitable for structural studies, which are currently ongoing.
    Matched MeSH terms: Escherichia coli/genetics
  3. Secretory expression in Escherichia coli and single-step purification of a heat-stable alkaline protease
    Fu Z, Hamid SB, Razak CN, Basri M, Salleh AB, Rahman RN
    Protein Expr Purif, 2003 Mar;28(1):63-8.
    PMID: 12651108
    Bacteriocin release proteins (BRPs) can be used for the release of heterologous proteins from the Escherichia coli cytoplasm into the culture medium. The gene for a highly thermostable alkaline protease was cloned from Bacillus stearothermophilus F1 by the polymerase chain reaction. The recombinant F1 protease was efficiently excreted into the culture medium using E. coli XL1-Blue harboring two vectors: pTrcHis bearing the protease gene and pJL3 containing the BRPs. Both vectors contain the E. coli lac promoter-operator system. In the presence of 40 microM IPTG, the recombinant F1 protease and the BRP were expressed and mature F1 protease was released into the culture medium. This opens the way for the large-scale production of this protease in E. coli. The recombinant enzyme was purified through a one-step heat treatment at 70 degrees C for 3h and this method purified the protease to near homogeneity. The purified enzyme showed a pH optimum of 9.0, temperature optimum of 80 degrees C, and was stable at 70 degrees C for 24h in the pH range from 8.0 to 10.0. The enzyme exhibited a high degree of thermostability with a half-life of 4 h at 85 degrees C, 25 min at 90 degrees C, and was inhibited by the serine protease inhibitor phenylmethylsulfonyl fluoride (PMSF).
    Matched MeSH terms: Escherichia coli/genetics*
  4. Fulltext Thermotolerance and molecular chaperone function of an SGT1-like protein from the psychrophilic yeast, Glaciozyma antarctica
    Yusof NA, Hashim NH, Beddoe T, Mahadi NM, Illias RM, Bakar FD, et al.
    Cell Stress Chaperones, 2016 Jul;21(4):707-15.
    PMID: 27154490 DOI: 10.1007/s12192-016-0696-2
    The ability of eukaryotes to adapt to an extreme range of temperatures is critically important for survival. Although adaptation to extreme high temperatures is well understood, reflecting the action of molecular chaperones, it is unclear whether these molecules play a role in survival at extremely low temperatures. The recent genome sequencing of the yeast Glaciozyma antarctica, isolated from Antarctic sea ice near Casey Station, provides an opportunity to investigate the role of molecular chaperones in adaptation to cold temperatures. We isolated a G. antarctica homologue of small heat shock protein 20 (HSP20), GaSGT1, and observed that the GaSGT1 mRNA expression in G. antarctica was markedly increased following culture exposure at low temperatures. Additionally, we demonstrated that GaSGT1 overexpression in Escherichia coli protected these bacteria from exposure to both high and low temperatures, which are lethal for growth. The recombinant GaSGT1 retained up to 60 % of its native luciferase activity after exposure to luciferase-denaturing temperatures. These results suggest that GaSGT1 promotes cell thermotolerance and employs molecular chaperone-like activity toward temperature assaults.
    Matched MeSH terms: Escherichia coli/metabolism
  5. Fulltext A Highly Sensitive Impedimetric DNA Biosensor Based on Hollow Silica Microspheres for Label-Free Determination of E. coli
    Yuhana Ariffin E, Heng LY, Tan LL, Abd Karim NH, Hasbullah SA
    Sensors (Basel), 2020 Feb 26;20(5).
    PMID: 32111092 DOI: 10.3390/s20051279
    A novel label-free electrochemical DNA biosensor was constructed for the determination of Escherichia coli bacteria in environmental water samples. The aminated DNA probe was immobilized onto hollow silica microspheres (HSMs) functionalized with 3-aminopropyltriethoxysilane and deposited onto a screen-printed electrode (SPE) carbon paste with supported gold nanoparticles (AuNPs). The biosensor was optimized for higher specificity and sensitivity. The label-free E. coli DNA biosensor exhibited a dynamic linear response range of 1 × 10-10 µM to 1 × 10-5 µM (R2 = 0.982), with a limit of detection at 1.95 × 10-15 µM, without a redox mediator. The sensitivity of the developed DNA biosensor was comparable to the non-complementary and single-base mismatched DNA. The DNA biosensor demonstrated a stable response up to 21 days of storage at 4 ℃ and pH 7. The DNA biosensor response was regenerable over three successive regeneration and rehybridization cycles.
    Matched MeSH terms: Escherichia coli/isolation & purification*
  6. Fulltext Characterization of the highly active polyhydroxyalkanoate synthase of Chromobacterium sp. strain USM2
    Bhubalan K, Chuah JA, Shozui F, Brigham CJ, Taguchi S, Sinskey AJ, et al.
    Appl Environ Microbiol, 2011 May;77(9):2926-33.
    PMID: 21398494 DOI: 10.1128/AEM.01997-10
    The synthesis of bacterial polyhydroxyalkanoates (PHA) is very much dependent on the expression and activity of a key enzyme, PHA synthase (PhaC). Many efforts are being pursued to enhance the activity and broaden the substrate specificity of PhaC. Here, we report the identification of a highly active wild-type PhaC belonging to the recently isolated Chromobacterium sp. USM2 (PhaC(Cs)). PhaC(Cs) showed the ability to utilize 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyhexanoate (3HHx) monomers in PHA biosynthesis. An in vitro assay of recombinant PhaC(Cs) expressed in Escherichia coli showed that its polymerization of 3-hydroxybutyryl-coenzyme A activity was nearly 8-fold higher (2,462 ± 80 U/g) than that of the synthase from the model strain C. necator (307 ± 24 U/g). Specific activity using a Strep2-tagged, purified PhaC(Cs) was 238 ± 98 U/mg, almost 5-fold higher than findings of previous studies using purified PhaC from C. necator. Efficient poly(3-hydroxybutyrate) [P(3HB)] accumulation in Escherichia coli expressing PhaC(Cs) of up to 76 ± 2 weight percent was observed within 24 h of cultivation. To date, this is the highest activity reported for a purified PHA synthase. PhaC(Cs) is a naturally occurring, highly active PHA synthase with superior polymerizing ability.
    Matched MeSH terms: Escherichia coli/genetics
  7. Fulltext Redirecting Metabolic Flux towards the Mevalonate Pathway for Enhanced β-Carotene Production in M. circinelloides CBS 277.49
    Naz T, Nazir Y, Nosheen S, Ullah S, Halim H, Fazili ABA, et al.
    Biomed Res Int, 2020;2020:8890269.
    PMID: 33457420 DOI: 10.1155/2020/8890269
    Carotenoids produced by microbial sources are of industrial and medicinal importance due to their antioxidant and anticancer properties. In the current study, optimization of β-carotene production in M. circinelloides strain 277.49 was achieved using response surface methodology (RSM). Cerulenin and ketoconazole were used to inhibit fatty acids and the sterol biosynthesis pathway, respectively, in order to enhance β-carotene production by diverting metabolic pool towards the mevalonate pathway. All three variables used in screening experiments were found to be significant for the production of β-carotene. The synergistic effect of the C/N ratio, cerulenin, and ketoconazole was further evaluated and optimized for superior β-carotene production using central composite design of RSM. Our results found that the synergistic combination of C/N ratios, cerulenin, and ketoconazole at different concentrations affected the β-carotene productions significantly. The optimal production medium (std. order 11) composed of C/N 25, 10 μg/mL cerulenin, and 150 mg/L ketoconazole, producing maximum β-carotene of 4.26 mg/L (0.43 mg/g) which was 157% greater in comparison to unoptimized medium (1.68 mg/L, 0.17 mg/g). So, it was concluded that metabolic flux had been successfully redirected towards the mevalonate pathway for enhanced β-carotene production in CBS 277.49.
    Matched MeSH terms: Escherichia coli/metabolism
  8. Fulltext Antidiarrheal, antimicrobial and antioxidant potentials of methanol extract of Colocasia gigantea Hook. f. leaves: evidenced from in vivo and in vitro studies along with computer-aided approaches
    Alam S, Rashid MA, Sarker MMR, Emon NU, Arman M, Mohamed IN, et al.
    BMC Complement Med Ther, 2021 Apr 12;21(1):119.
    PMID: 33845836 DOI: 10.1186/s12906-021-03290-6
    BACKGROUND: Colocasia gigantea, locally named as kochu is well-known due to its various healing power. This research is to investigate the antidiarrheal, antimicrobial and antioxidant possibilities of the methanol soluble extract of Colocasia gigantea.

    METHODS: The antidiarrheal investigation was performed by using in vivo castor oil-induced diarrheal method whereas in vitro antimicrobial and antioxidant investigation have been implemented by disc diffusion and DPPH scavenging method respectively. Moreover, in silico studies were followed by molecular docking analysis of several secondary metabolites that were appraised with Schrödinger-Maestro v11.1 and Biovia Discovery Studio.

    RESULTS: The induction of plant extract (200 and 400 mg/kg, b.w, p.o) has minimized the castor oil mediated diarrhea by 16.96% (p 

    Matched MeSH terms: Escherichia coli/drug effects
  9. Fulltext Microbiological Safety of Street-Vended Beverages in Chow Kit, Kuala Lumpur
    Mohd Nawawee NS, Abu Bakar NF, Zulfakar SS
    Int J Environ Res Public Health, 2019 Nov 13;16(22).
    PMID: 31766289 DOI: 10.3390/ijerph16224463
    Improper handling, poor hygienic practices, and lack of environmental control affect the safety of street-vended beverages. The objective of this study is to determine the bacterial contamination level of three types of beverages (cordial-based drinks, milk-based drinks, fruit juices) sold by street vendors at Chow Kit, Kuala Lumpur. A total of 31 samples of beverages were analyzed to determine total viable count (TVC), total coliform, Escherichia coli, and Staphylococcus aureus counts via the standard plate count method. The results showed that only 9.7% of the total samples were not contaminated with the tested microorganisms. All milk-based drink samples were positive for TVC and also had the highest average bacterial counts at 5.30 ± 1.11 log Colony Forming Unit/mL (CFU/mL). About 71% of the samples were contaminated with total coliform with the average readings ranging between 4.30 and 4.75 log CFU/mL, whereas 58.1% of the samples were positive with S. aureus, with fruit juices having the highest average reading (3.42 ± 1.15 log CFU/mL). Only one sample (milk-based drink) was E. coli positive. This study showed that the microbiological safety level of street-vended beverages in Chow Kit, Kuala Lumpur was average and needs to be improved. Provision of food safety education and adequate sanitary facilities at vending sites are suggested to increase the safety of food products.
    Matched MeSH terms: Escherichia coli/isolation & purification
  10. Fulltext Prevalence and molecular characterization of ESBL-producing Escherichia coli isolated from broiler chicken and their respective farms environment in Malaysia
    Lemlem M, Aklilu E, Mohamed M, Kamaruzzaman NF, Devan SS, Lawal H, et al.
    BMC Microbiol, 2024 Nov 26;24(1):499.
    PMID: 39592959 DOI: 10.1186/s12866-024-03653-2
    BACKGROUND: Extended spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) is an increasing public health threat. This study aimed to determine the prevalence and characterization of ESBL-producing Escherichia coli (E. coli) isolated from broiler chicken and their farm environment, in Kelantan Malaysia.

    METHODS: Escherichia coli was isolated from 453 collected samples, including 210 cloacal swabs and 243 environmental samples. The antimicrobial susceptibility profile of the E. coli isolates was assessed for sixteen antibiotics using the disc diffusion method. The E. coli isolates were evaluated for phenotypic ESBL production using modified double disc synergy. After extraction of genomic DNA, ESBL resistance genes, phylogenetic group, and virulence genes were detected by PCR using appropriate primers. ESBL genes were further confirmed by sequencing. The molecular typing of E. coli strains was determined by Multilocus Sequence Typing (MLST).

    RESULTS: A total of 93.8% (425/453) E. coli were isolated from the collected samples. Out of 334 E. coli isolates screened, 14.7% (49/334) were phenotypically ESBL producers. All the ESBL-EC were resistant to tetracycline, ciprofloxacin, and ampicillin. Thus, 100% of the ESBL-EC were multidrug resistant. Of the ESBL-EC 81.6% were positive for at least one ESBL encoding gene. The most prevalent ESBL gene detected was blaTEM (77.6%; 38/49) followed by blaCTX-M (32.7%; 16/49) and blaSHV (18.4%; 9/49). The majority of ESBL-EC belonged to phylogenic groups A followed by B1 accounting for 44.9% and 12.2%, respectively. The most frequently identified sequence types were ST10 (n = 3) and ST206 (n = 3). The most detected virulence genes in the E. coli isolates were astA (33.3%; 22/66) followed by iss (15.2%; 10/66).

    CONCLUSIONS: Our results show both broiler chicken and their respective farms environment were reservoirs of multi-drug resistant ESBL-producing E. coli and ESBL resistance genes.

    Matched MeSH terms: Escherichia coli Proteins/genetics
  11. N-terminally His-tagged hepatitis B core antigens: construction, expression, purification and antigenicity
    Yap WB, Tey BT, Ng MY, Ong ST, Tan WS
    J Virol Methods, 2009 Sep;160(1-2):125-31.
    PMID: 19433111 DOI: 10.1016/j.jviromet.2009.04.038
    The core antigen of the hepatitis B virus (HBcAg) has been used widely as a diagnostic reagent for the identification of the viral infection. However, purification using the conventional sucrose density gradient ultracentrifugation is time consuming and costly. To overcome this, HBcAg particles displaying His-tag on their surface were constructed and produced in Escherichia coli. The recombinant His-tagged HBcAgs were purified using immobilized metal affinity chromatography. Transmission electron microscopy and enzyme-linked immunosorbent assay (ELISA) revealed that the displayed His-tag did not impair the formation of the core particles and the antigenicity of HBcAg.
    Matched MeSH terms: Escherichia coli/genetics
  12. Fulltext Mutagenicity evaluation of Anastatica hierochuntica L. aqueous extract in vitro and in vivo
    Md Zin SR, Mohamed Z, Alshawsh MA, Wong WF, Kassim NM
    Exp Biol Med (Maywood), 2018 Feb;243(4):375-385.
    PMID: 29237294 DOI: 10.1177/1535370217748574
    Anastatica hierochuntica L. ( A. hierochuntica), a folk medicinal plant, was evaluated for mutagenic potential via in vitro and in vivo assays. The in vitro assay was conducted according to modified Ames test, while the in vivo study was performed according to Organisation for Economic Co-operation and Development guideline for mammalian erythrocyte micronucleus assay. Four groups ( n= 5 males and 5 females per group) Sprague Dawley rats were randomly chosen as the negative control, positive control (received a single intramuscular injection of cyclophosphamide 50 mg/kg), 1000 and, 2000 mg/kg A. hierochuntica aqueous extracts. All groups except the positive control were treated orally for three days. Findings of the in vitro assay showed mutagenic potential of AHAE at 0.04 and 0.2 mg/ml. However, no mutagenic effect was demonstrated in the in vivo study up to 2000 mg/kg. No significant reduction in the polychromatic and normochromatic erythrocytes ratio was noted in any of the groups. Meanwhile, high micronucleated polychromatic erythrocytes frequency was seen in cyclophosphamide-treated group only. These findings could perhaps be due to insufficient dosage of A. hierochuntica aqueous extracts to cause genetic damage on the bone marrow target cells. Further acute and chronic in vivo toxicity studies may be required to draw pertinent conclusion on the safety aspect of A. hierochuntica aqueous extracts consumption. Impact statement In this paper, we report on the mutagenicity evaluation of Anastatica hierochuntica aqueous extract. This is a significant research in view of the popularity of this herb consumption by the people across the globe despite of limited scientific evidence on its toxicity potential. This study is intended to encourage more extensive related research in order to provide sufficient evidence and guidance for determining its safe dosage.
    Matched MeSH terms: Escherichia coli/drug effects
  13. Modulation of cell surface hydrophobicity and attachment of bacteria to abiotic surfaces and shrimp by Malaysian herb extracts
    Hui YW, Dykes GA
    J Food Prot, 2012 Aug;75(8):1507-11.
    PMID: 22856578 DOI: 10.4315/0362-028X.JFP-12-062
    The use of simple crude water extracts of common herbs to reduce bacterial attachment may be a cost-effective way to control bacterial foodborne pathogens, particularly in developing countries. The ability of water extracts of three common Malaysian herbs (Andrographis paniculata, Eurycoma longifolia, and Garcinia atroviridis) to modulate hydrophobicity and attachment to surfaces of five food-related bacterial strains (Bacillus cereus ATCC 14576, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 10145, Salmonella Enteritidis ATCC 13076, Staphylococcus aureus ATCC 25923) were determined. The bacterial attachment to hydrocarbon assay was used to determine bacterial hydrophobicity. Staining and direct microscopic counts were used to determine attachment of bacteria to glass and stainless steel. Plating on selective media was used to determine attachment of bacteria to shrimp. All extracts were capable of either significantly ( P < 0.05) increasing or decreasing bacterial surface hydrophobicity, depending on the herb extract and bacteria combination. Bacterial attachment to all surfaces was either significantly (P < 0.05) increased or decreased, depending on the herb extract and bacteria combination. Overall, hydrophobicity did not show a significant correlation (P > 0.05) to bacterial attachment. For specific combinations of bacteria, surface material, and plant extract, significant correlations (R > 0.80) between hydrophobicity and attachment were observed. The highest of these was observed for S. aureus attachment to stainless steel and glass after treatment with the E. longifolia extract (R = 0.99, P < 0.01). The crude water herb extracts in this study were shown to have the potential to modulate specific bacterial and surface interactions and may, with further work, be useful for the simple and practical control of foodborne pathogens.
    Matched MeSH terms: Escherichia coli/physiology
  14. Detection of betalactamase producing bacterial genes and their clinical features
    Hashim RB, Husin S, Rahman MM
    Pak J Biol Sci, 2011 Jan 01;14(1):41-6.
    PMID: 21913496
    The present study was aimed to identify the gene of drug resistance betalactamase producing bacteria and clinical features of the infected patients at Hospital University Kebangsaan Malaysia. Blood samples from the patients were collected, processed and betalactamase producing drug resistance bacteria were identified by antibiotic sensitivity testing. Genes of the drug resistance bacteria were detected and characterized by polymerase chain reaction. A total of 34 isolates of drug resistance Betalactamase producing E. coli and Klebsiella spp. were isolated from 2,502 patients. Most common drug resistance gene TEM was found in 50% of the isolates. 11% was found positive for both TEM and SHV. Next 11% of the isolates expressed only SHV genes. Clinical features of the patients were recorded from where the bacteria isolated. Regarding community affiliations 70.5% of the infected patients were Malay 17.6% were Indian and 11.7% were Chinese. Majority of the patients has an underlying pre-morbid condition as reflected by their diagnosis. Better infection control and hygiene in hospitals, plus controlled and prudent use of antibiotics, is required to minimize the impact of drug resistance betalactamase producing bacteria and the spread of infections.
    Matched MeSH terms: Escherichia coli/genetics
  15. Design, Synthesis and Pro-Inflammatory Activity of Palmitoylated Derivatives of Thioglycolic Acid as New Immunomodulators
    Mohamed SM, Abou-Ghadir OMF, El-Mokhtar MA, Aboraia AS, Abdel-Moty SG, Abdel-Aal AM
    Chem Biol Drug Des, 2024 Dec;104(6):e70029.
    PMID: 39702898 DOI: 10.1111/cbdd.70029
    The immune system is essential for the defense against infections and is critically implicated in various disorders, including immunodeficiency, autoimmunity, inflammation and cancer. The current study includes a new design of palmitoylated derivatives of thioglycolic acids (PTGAs) capable of triggering innate immune responses. The new series were accessible through a three-step synthetic route, including N-palmitoylation, Claisen-Schmidt condensation and thia-Michael addition. Their structures were elucidated using different 1D and 2D NMR spectroscopic techniques and their purity was confirmed by elemental analysis. The most active PTGAs induced a 12-26-fold increase in the expression of TNF-α and IL-1β mRNA and triggered a marked release of NO in isolated macrophages. These levels were comparable to the responses elicited by heat-killed E. coli and S. aureus. The position of the palmitamide chain and aryl substitution had a significant effect on the TNF-α and IL-1β mRNA expression and NO release. Simulations of molecular dockings showed that the new PTGA derivatives occupy the same TLR2/TLR6 heterodimer active binding site of the microbial diacylated lipoproteins. The new immunomodulators may have a profound impact on various clinical disorders associated with dysfunctional innate immunity.
    Matched MeSH terms: Escherichia coli/drug effects
  16. Fulltext Characterization of a novel subfamily 1.4 lipase from Bacillus licheniformis IBRL-CHS2: Cloning and expression optimization
    Khazaal Kadhim Almansoori A, Reddy NS, Abdulfattah M, Ismail SS, Abdul Rahim R
    PLoS One, 2024;19(12):e0314556.
    PMID: 39689112 DOI: 10.1371/journal.pone.0314556
    This study focuses on a novel lipase from Bacillus licheniformis IBRL-CHS2. The lipase gene was cloned into the pGEM-T Easy vector, and its sequences were registered in GenBank (KU984433 and AOT80658). It was identified as a member of the bacterial lipase subfamily 1.4. The pCold I vector and E. coli BL21 (DE3) host were utilized for expression, with the best results obtained by removing the enzyme's signal peptide. Optimal conditions were found to be 15°C for 24 h, using 0.2 mM Isopropyl β-D-1-thiogalactopyranoside (IPTG). The His-tagged lipase was purified 13-fold with a 68% recovery and a specific activity of 331.3 U/mg using affinity purification. The lipase demonstrated optimal activity at 35°C and pH 7. It remained stable after 24 h in 25% (v/v) organic solvents such as isooctane, n-hexane, dimethyl sulfoxide (DMSO), and methanol, which enhanced its activity. Chloroform and diethyl ether inhibited the lipase. The enzyme exhibited the highest affinity for p-nitrophenol laurate (C12:0) with a Km of 0.36 mM and a Vmax of 357 μmol min-1 mg-1. Among natural oils, it performed best with coconut oil and worst with olive oil. The lipase was stable in the presence of 1 mM and 5 mM Ca2⁺, K⁺, Na⁺, Mg2⁺, and Ba2⁺, but its activity decreased with Zn2⁺ and Al3⁺. Non-ionic surfactants like Triton X-100, Nonidet P40, Tween 20, and Tween 40 boosted activity, while Sodium Dodecyl Sulfate (SDS) inhibited it. This lipase's unique properties, particularly its stability in organic solvents, make it suitable for applications in organic synthesis and various industries.
    Matched MeSH terms: Escherichia coli/genetics
  17. A PROspective study on the Usage patterns of Doripenem in the Asia-Pacific region (PROUD study)
    Mustafa M, Chan WM, Lee C, Harijanto E, Loo CM, Van Kinh N, et al.
    Int J Antimicrob Agents, 2014 Apr;43(4):353-60.
    PMID: 24636429 DOI: 10.1016/j.ijantimicag.2014.01.017
    Doripenem is approved in the Asia-Pacific (APAC) region for treating nosocomial pneumonia (NP) including ventilator-associated pneumonia (VAP), complicated intra-abdominal infections (cIAIs) and complicated urinary tract infections (cUTIs). Clinical usage of doripenem (500mg intravenously, infused over 1h or 4h every 8h for 5-14 days) in APAC was evaluated in a prospective, open-label, non-comparative, multicentre study of inpatients (≥18 years) with NP, VAP, cIAI or cUTI. A total of 216 [intention-to-treat (ITT)] patients received doripenem: 53 NP (24.5%); 77 VAP (35.6%); 67 cIAI (31.0%); and 19 cUTI (8.8%). Doripenem MIC90 values for Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Klebsiella pneumoniae were 32, 32, 0.094 and 0.64μg/mL, respectively. Doripenem was used most commonly as monotherapy (86.6%) and as second-line therapy (62.0%). The clinical cure rate in clinically evaluable patients was 86.7% at the end of therapy (EOT) and 87.1% at test of cure (TOC) (7-14 days after EOT). In the ITT population, overall clinical cure rates were 66.2% at EOT and 56.5% at TOC. The median duration of hospital stay, intensive care unit (ICU) stay and mechanical ventilation was 20, 12 and 10 days, respectively. Of 146 discharged patients, 7 were re-admitted within 28 days of EOT; 1 VAP patient was re-admitted to the ICU. The all-cause mortality rate was 22.7% (49/216). The most common treatment-related adverse events were diarrhoea (1.4%) and vomiting (1.4%). Doripenem is a viable option for treating APAC patients with NP, VAP, cIAI or cUTI. [ClinicalTrials.gov: NCT 00986102].
    Matched MeSH terms: Escherichia coli/drug effects; Escherichia coli/pathogenicity; Escherichia coli Infections/drug therapy
  18. The capacity for long-chain polyunsaturated fatty acid synthesis in a carnivorous vertebrate: Functional characterisation and nutritional regulation of a Fads2 fatty acyl desaturase with Δ4 activity and an Elovl5 elongase in striped snakehead (Channa striata)
    Kuah MK, Jaya-Ram A, Shu-Chien AC
    Biochim. Biophys. Acta, 2015 Mar;1851(3):248-60.
    PMID: 25542509 DOI: 10.1016/j.bbalip.2014.12.012
    The endogenous production of long-chain polyunsaturated fatty acids (LC-PUFA) in carnivorous teleost species inhabiting freshwater environments is poorly understood. Although a predatory lifestyle could potentially supply sufficient LC-PUFA to satisfy the requirements of these species, the nutrient-poor characteristics of the freshwater food web could impede this advantage. In this study, we report the cloning and functional characterisation of an elongase enzyme in the LC-PUFA biosynthesis pathway from striped snakehead (Channa striata), which is a strict freshwater piscivore that shows high deposition of LC-PUFA in its flesh. We also functionally characterised a previously isolated fatty acyl desaturase cDNA from this species. Results showed that the striped snakehead desaturase is capable of Δ4 and Δ5 desaturation activities, while the elongase showed the characteristics of Elovl5 elongases. Collectively, these findings reveal that striped snakehead exhibits the genetic resources to synthesise docosahexaenoic acid (DHA; 22:6n-3) from eicosapentaenoic acid (EPA; 20:5n-3). Both genes are expressed at considerable levels in the brain and the liver. In liver, both genes were up-regulated by dietary C18 PUFA, although this increase did not correspond to a significant rise in the deposition of muscle LC-PUFA. Brain tissue of fish fed with plant oil diets showed higher expression of fads2 gene compared to fish fed with fish oil-based diet, which could ensure DHA levels remain constant under limited dietary DHA intake. This suggests the importance of DHA production from EPA via the ∆4 desaturation step in order to maintain an optimal reserve of DHA in the neuronal tissues of carnivores.
    Matched MeSH terms: Escherichia coli/genetics; Escherichia coli/metabolism
  19. Fulltext Protein engineering of selected residues from conserved sequence regions of a novel Anoxybacillus α-amylase
    Ranjani V, Janeček S, Chai KP, Shahir S, Abdul Rahman RN, Chan KG, et al.
    Sci Rep, 2014 Jul 28;4:5850.
    PMID: 25069018 DOI: 10.1038/srep05850
    The α-amylases from Anoxybacillus species (ASKA and ADTA), Bacillus aquimaris (BaqA) and Geobacillus thermoleovorans (GTA, Pizzo and GtamyII) were proposed as a novel group of the α-amylase family GH13. An ASKA yielding a high percentage of maltose upon its reaction on starch was chosen as a model to study the residues responsible for the biochemical properties. Four residues from conserved sequence regions (CSRs) were thus selected, and the mutants F113V (CSR-I), Y187F and L189I (CSR-II) and A161D (CSR-V) were characterised. Few changes in the optimum reaction temperature and pH were observed for all mutants. Whereas the Y187F (t1/2 43 h) and L189I (t1/2 36 h) mutants had a lower thermostability at 65°C than the native ASKA (t1/2 48 h), the mutants F113V and A161D exhibited an improved t1/2 of 51 h and 53 h, respectively. Among the mutants, only the A161D had a specific activity, k(cat) and k(cat)/K(m) higher (1.23-, 1.17- and 2.88-times, respectively) than the values determined for the ASKA. The replacement of the Ala-161 in the CSR-V with an aspartic acid also caused a significant reduction in the ratio of maltose formed. This finding suggests the Ala-161 may contribute to the high maltose production of the ASKA.
    Matched MeSH terms: Escherichia coli/genetics; Escherichia coli/metabolism
  20. RK-1355A and B, novel quinomycin derivatives isolated from a microbial metabolites fraction library based on NPPlot screening
    Lim CL, Nogawa T, Uramoto M, Okano A, Hongo Y, Nakamura T, et al.
    J Antibiot (Tokyo), 2014 Apr;67(4):323-9.
    PMID: 24496142 DOI: 10.1038/ja.2013.144
    Two novel quinomycin derivatives, RK-1355A (1) and B (2), and one known quinomycin derivative, UK-63,598 (3), were isolated from a microbial metabolites fraction library of Streptomyces sp. RK88-1355 based on Natural Products Plot screening. The structural elucidation of 1 and 2 was established through two-dimensional NMR and mass spectrometric measurements. They belong to a class of quinomycin antibiotics family having 3-hydroxyquinaldic acid and a sulfoxide moiety. They are the first examples for natural products as a quinoline type quinomycin having a sulfoxide on the intramolecular cross-linkage. They showed potent antiproliferative activities against various cancer cell lines and they were also found to exhibit moderate antibacterial activity.
    Matched MeSH terms: Escherichia coli/drug effects*; Escherichia coli/growth & development
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