Fabrication and characterization of the novel bionanocomposite poly(ester-imide-sulfonamide)s/Ag film coated on glass bead for inactivation of E. coli

2021 ◽  
Author(s):  
Mahboobeh Soleimani ◽  
Farhang Tirgir ◽  
Mohammad Dinari
Keyword(s):  
Glass Bead ◽  
The Novel ◽  
E Coli ◽  
Fabrication And Characterization ◽  
Ag Film

Characterization of novel ybjG and dacC variants in Escherichia coli

2013 ◽  
Vol 62 (11) ◽  
pp. 1728-1734 ◽  
Author(s):  
Dongguo Wang ◽  
Enping Hu ◽  
Jiayu Chen ◽  
Xiulin Tao ◽  
Katelyn Gutierrez ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multiple Drug Resistance ◽  
Multiple Drug ◽  
The Novel ◽  
Conventional Pcr ◽  
E Coli ◽  
Novel Variants ◽  
Restriction Sites ◽  
Genetic Structures

A total of 69 strains of Escherichia coli from patients in the Taizhou Municipal Hospital, China, were isolated, and 11 strains were identified that were resistant to bacitracin, chloramphenicol, tetracycline and erythromycin. These strains were PCR positive for at least two out of three genes, ybjG, dacC and mdfA, by gene mapping with conventional PCR detection. Conjugation experiments demonstrated that these genes existed in plasmids that conferred resistance. Novel ybjG and dacC variants were isolated from E. coli strains EC2163 and EC2347, which were obtained from the sputum of intensive care unit patients. Genetic mapping showed that the genes were located on 8200 kb plasmid regions flanked by EcoRI restriction sites. Three distinct genetic structures were identified among the 11 PCR-positive strains of E. coli, and two contained the novel ybjG and dacC variants. The putative amino acid differences in the ybjG and dacC gene variants were characterized. These results provide evidence for novel variants of ybjG and dacC, and suggest that multiple drug resistance in hospital strains of E. coli depends on the synergistic function of ybjG, dacC and mdfA within three distinct genetic structures in conjugative plasmids.

scholarly journals Bacteria Exposed to Silver Nanoparticles Synthesized by Laser Ablation in Water: Modelling E. coli Growth and Inactivation

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 653 ◽  
Author(s):  
Lucija Krce ◽  
Matilda Šprung ◽  
Ana Maravić ◽  
Polona Umek ◽  
Krešimir Salamon ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Bacterial Growth ◽  
Growth Curves ◽  
Dynamic State ◽  
Lag Phase ◽  
The Novel ◽  
Minimal Inhibitory Concentrations ◽  
E Coli ◽  
Main Effect

This study is aimed to better understand the bactericidal mode of action of silver nanoparticles. Here we present the production and characterization of laser-synthesized silver nanoparticles along with growth curves of bacteria treated at sub-minimal and minimal inhibitory concentrations, obtained by optical density measurements. The main effect of the treatment is the increase of the bacterial apparent lag time, which is very well described by the novel growth model as well as the entire growth curves for different concentrations. The main assumption of the model is that the treated bacteria uptake the nanoparticles and inactivate, which results in the decrease of both the nanoparticles and the bacteria concentrations. The lag assumes infinitive value for the minimal inhibitory concentration treatment. This apparent lag phase is not postponed bacterial growth. It is a dynamic state in which the bacterial growth and death rates are close in value. Our results strongly suggest that the predominant mode of antibacterial action of silver nanoparticles is the penetration inside the membrane.

scholarly journals Development and Characterization of Bioactive Polypropylene Films for Food Packaging Applications

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3478
Author(s):  
Adrian Krzysztof Antosik ◽  
Urszula Kowalska ◽  
Magdalena Stobińska ◽  
Paulina Dzięcioł ◽  
Magdalena Pieczykolan ◽  
...  
Keyword(s):  
Food Packaging ◽  
Antimicrobial Properties ◽  
The Novel ◽  
E Coli ◽  
Synthetic Product ◽  
Natural Agents ◽  
Plastic Materials ◽  
Study Results ◽  
Oregano Oil

Bioactive polypropylene (PP) films with active agents) presence for food packaging application have been prepared and characterized. The novel modified PP films were obtained via PP/additives systems regranulation and cast extrusion. The influence of two types of plasticizers (natural agents as well as commercial synthetic product) and bioactive additives on final features, e.g., mechanical properties, was evaluated. Moreover, the biocidal activity of the films was determined. Due to their functional properties, they are developed as additives to packaging plastic materials such as polyolefins. The study results presented in our work may indirectly contribute to environmental protection by reducing food waste. The aim of the work was to obtain innovative, functional packaging materials with an ability to prolong the shelf life of food products. The best antimicrobial properties were observed for the sample based on 5 wt.% oregano oil (OO) and 5 wt.% cedar oil (OC) in PP matrix. A microbial test revealed that the system causes total reduction in the following microorganisms: B. subtilis, E. coli, S. aureus, P. putida, C. albicans, A. alternata, F. oxysporum.

Fabrication and characterization of the novel shape-stabilized composite PCMs of Na2CO3-K2CO3/MgO/glass

Solar Energy ◽  
2019 ◽  
Vol 189 ◽  
pp. 228-234 ◽  
Author(s):  
Yunkun Lu ◽  
Gaoqun Zhang ◽  
Junjie Hao ◽  
Zhongkai Ren ◽  
Zhanfeng Deng ◽  
...  
Keyword(s):  
The Novel ◽  
Fabrication And Characterization

scholarly journals Genetic and Kinetic Characterization of the Novel AmpC β-Lactamases DHA-6 and DHA-7

2014 ◽  
Vol 58 (11) ◽  
pp. 6544-6549 ◽  
Author(s):  
Francisco José Pérez-Llarena ◽  
Laura Zamorano ◽  
Frédéric Kerff ◽  
Alejandro Beceiro ◽  
Patricia García ◽  
...  
Keyword(s):  
Enterobacter Cloacae ◽  
Slight Reduction ◽  
The Novel ◽  
Incompatibility Group ◽  
Content Type ◽  
E Coli ◽  
Natural Variants ◽  
Tertiary Protein Structure ◽  
Hydrolysis Of

ABSTRACTDuring a Spanish surveillance study, two natural variants of DHA β-lactamases, DHA-6 and DHA-7, were found, with the replacements Ala226Thr and Phe322Ser, respectively, with respect to DHA-1. The DHA-6 and DHA-7 enzymes were isolated fromEscherichia coliandEnterobacter cloacaeclinical isolates, respectively. The aim of this study was to genetically, microbiologically, and biochemically characterize the DHA-6 and DHA-7 β-lactamases. TheblaDHA-6andblaDHA-7genes were located in the I1 and HI2 incompatibility group plasmids of 87.3 and 310.4 kb, respectively. The genetic contexts ofblaDHA-6andblaDHA-7were similar to that already described for theblaDHA-1gene and included theqnrB4andaadAgenes. The MICs for cephalothin, aztreonam, cefotaxime, and ceftazidime were 8- to 32-fold lower for DHA-6 than for DHA-1 or DHA-7 expressed in the same isogenicE. coliTG1 strain. Interestingly, the MIC for cefoxitin was higher in the DHA-6-expressing transformant than in DHA-1 or DHA-7. Biochemical studies with pure β-lactamases revealed slightly lower catalytic efficiencies of DHA-6 against cephalothin, ceftazidime, and cefotaxime than those of DHA-1 and DHA-7. To understand this behavior, stability experiments were carried out and showed that the DHA-6 protein displayed significantly higher stability than the DHA-1 and DHA-7 enzymes. The proximity of Thr226 to the N terminus in the tertiary protein structure in DHA-6 may promote this stabilization and, consequently, may induce a slight reduction in the dynamic of this enzyme that primarily affects the hydrolysis of some of the bulkiest antibiotics.

scholarly journals Fabrication and characterization of fine ceramic based on alumina, bentonite, and glass bead

2018 ◽  
Vol 985 ◽  
pp. 012024 ◽  
Author(s):  
P Sebayang ◽  
Nurdina ◽  
S Simbolon ◽  
C Kurniawan ◽  
M Yunus ◽  
...  
Keyword(s):  
Glass Bead ◽  
Fine Ceramic ◽  
Fabrication And Characterization

scholarly journals Characterization of Three GADs from Bacillus spp. for Efficient γ-Aminobutyric Acid Production

2021 ◽  
Author(s):  
Lei Sun ◽  
Yingguo Bai ◽  
Xiu Zhang ◽  
Cheng Zhou ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Catalytic Efficiency ◽  
Cost Effective ◽  
Aminobutyric Acid ◽  
The Novel ◽  
Functional Identification ◽  
E Coli ◽  
Bacillus Spp ◽  
Optimal Reaction Temperature ◽  
Repeated Use

Abstract BackgroundGamma-aminobutyric acid (GABA) is an important bio-product used in pharmaceuticals and functional foods and as a precursor of the biodegradable plastic polyamide 4. Glutamate decarboxylase (GAD) converts l-glutamate (l-Glu) into GABA via decarboxylation. Compared with other methods, develop a bioconversion platform to produce GABA is of considerable interest for industrial use.ResultsThree GAD genes were identified from three Bacillus strains and heterologously expressed in Escherichia coli BL21 (DE3). The optimal reaction temperature and pH values for three enzymes were 40 °C and 5.0, respectively. Of the GADs, GADZ11 had the highest catalytic efficiency towards l-Glu (2.19 mM− 1·s− 1). The engineered E. coli strain that expressed GADZ11 was used as a whole-cell biocatalyst for the production of GABA. After repeated use 8 times, the cells produced GABA with an average molar conversion rate of 97% within 8 h.ConclusionsThree recombinant GADs from Bacillus strains have been conducted functional identification. And engineered E. coli strain heterologous expressing GADZ1, GADZ11, and GADZ20 could accomplish the biosynthesis of l-Glu to GABA in a buffer-free reaction at a high l-Glu concentration. The novel engineered E. coli strain has the potential to be a cost-effective biotransformation platform for the industrial production of GABA.

scholarly journals Study of a Natural Mutant SHV-Typeβ-Lactamase, SHV-104, fromKlebsiella pneumoniae

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Nahed Ben Achour ◽  
Omrane Belhadj ◽  
Moreno Galleni ◽  
Mohamed Ben Moussa ◽  
Paola Sandra Mercuri
Keyword(s):  
Salt Bridge ◽  
Conjugative Plasmid ◽  
Military Hospital ◽  
The Novel ◽  
Minimal Inhibitory Concentrations ◽  
E Coli ◽  
Novel Variant ◽  
The Military

Klebsiella pneumoniaeML2011, a multiresistant isolate, was isolated from the Military Hospital of Tunis (Tunisia). The determination of the minimal inhibitory concentrations exhibited byK. pneumoniaeML2011 was performed by Etest. The crude extract of the isolates contains four differentβ-lactamases with pI 5.5, 7.3, 7.6, and 8.6. Only theβ-lactamases with pI 7.3 and pI 8.6 were transferred by transformation and conjugation experiment. Molecular characterization of these genes was performed by PCR and sequencing. The chromosomalβ-lactamases are TEM (pI 5.5) and SHV-1 (7.6). CTX-M-28 (pI 8.6) and the novel variant of SHV named SHV-104 (pI 7.3) were encoded byblagene located on a 50 kb highly conjugative plasmid. The SHV-104β-lactamase was produced inE. coliand purified. Its profile of activity was determined. Compared to SHV-1, SHV-104 contains one mutation, R202S. Their kinetic parameters were similar except for cefotaxime. The analysis of the predicted structure of SHV-104 indicated that the R202S mutation suppresses a salt bridge present in SHV-1. Therefore, the overall flexibility of the protein increased and might improve the hydrolysis of cefotaxime. We can conclude that the multiresistant phenotype ofK. pneumoniaeML2011 strain is mainly linked to the production of CTX-M-28 since SHV-104 possesses a narrow spectrum of activity.

A new isopentenyl diphosphate isomerase gene from sweet potato: cloning, characterization and color complementation

Biologia ◽  
2008 ◽  
Vol 63 (2) ◽  
Author(s):  
Zhihua Liao ◽  
Min Chen ◽  
Yijian Yang ◽  
Chunxian Yang ◽  
Yufan Fu ◽  
...  
Keyword(s):  
Sweet Potato ◽  
Carotenoid Biosynthesis ◽  
Tissue Expression ◽  
Isopentenyl Diphosphate ◽  
The Novel ◽  
Isopentenyl Diphosphate Isomerase ◽  
E Coli ◽  
Dimethylallyl Diphosphate ◽  
Tissue Expression Analysis

AbstractIsopentenyl diphosphate isomerase (IDI, EC 5.3.3.2) catalyzes the revisable conversion of 5-carbon isopentenyl diphosphate and its isomer dimethylallyl diphosphate, which are the essential precursors for isoprenoids, including carotenoids. Here we report on the cloning and characterization of a novel cDNA encoding IDI from sweet potato. The full-length cDNA is 1155 bp with an ORF of 892 bp encoding a polypeptide of 296 amino acids, which was designated as IbIDI (GenBank Acc. No: DQ150100). The computational molecular weight is 33.8 kDa and the theoretical isoelectric point is 5.76. The deduced amino acid sequence of IbIDI is similar to the known plant IDIs. The tissue expression analysis revealed that IbIDI expressed at higher level in sweet-potato’s mature leaves and tender leaves than that in tubers, meanwhile, no expression signal could be detected in veins. Recombinant IbIDI was heterologously expressed in engineered Escherichia coli which led to the reconstruction of the carotenoid pathway. In the engineered E. coli, IbIDI could take the role of Arabidopsis IDI gene to produce the orange β-carotene. In summary, cloning and characterization of the novel IDI gene from sweet potato will facilitate our understanding of the molecular genetical mechanism of carotenoid biosynthesis and promote the metabolic engineering studies of carotenoid in sweet potato.

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