Relative Strengths and Regulation of Different Promoter-Associated Sequences for Various blaSHV Genes and Their Relationships to β-Lactam Resistance

2017 ◽  
Vol 27 (2) ◽  
pp. 91-101 ◽  
Author(s):  
Yao Zhai ◽  
Zhao Zhang ◽  
Zhanwei Wang ◽  
Yusheng Chen ◽  
Qi Wang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Green Fluorescent Protein ◽  
Mrna Expression ◽  
Inhibitory Concentration ◽  
Fluorescent Protein ◽  
Mrna Levels ◽  
Associated Sequences ◽  
Regulation Function ◽  
Green Fluorescent ◽  
Mrna Expression Levels

<b><i>Aims:</i></b> This work investigated the relative strengths of different <i>bla</i><sub>SHV</sub> promoter-associated sequences and their regulation function in <i>bla</i><sub>SHV</sub> expression and β-lactam resistance. <b><i>Methods:</i></b> Recombinant plasmids with the promoter-associated sequences (P-W, P-S, P-IS, and P-WPD), <i>tac</i> promoter, and combined fragments of promoter and <i>bla</i><sub>SHV</sub> were separately constructed and transformed into <i>Escherichia coli</i> DH5α. The relative strengths of the promoters indicated by the intensities of green fluorescent protein and the mRNA expression levels of <i>bla</i><sub>SHV</sub> were compared. The minimum inhibitory concentration and extended spectrum β-lactamase phenotypes were evaluated. <b><i>Results:</i></b> The relative strengths were ranked as P-<i>tac</i> > P-WPD > P-IS > P-S > P-W. The mRNA expression and β-lactam resistance levels of the different promoter-associated sequence groups were generally consistent with the strength rank, but the extent of <i>gfp</i> and <i>bla</i><sub>SHV</sub> mRNA levels varied significantly in each group. The β-lactam resistance levels were inconsistent with the strength rank in certain <i>bla</i><sub>SHV</sub> groups. In relation to the different promoter-associated sequences,<i> bla</i><sub>SHV-ESBLs</sub> displayed significantly different change modes of β-lactam resistance compared with <i>bla</i><sub>SHV-non-ESBLs</sub>. <b><i>Conclusion:</i></b> The mRNA expression and β-lactam resistance of the <i>bla</i><sub>SHV</sub> showed consistencies and inconsistencies with the strengths of the promoter-associated sequences. The mechanisms accounting for these discrepancies need further investigation.

scholarly journals The Functional Quality of Soluble Recombinant Polypeptides Produced in Escherichia coli Is Defined by a Wide Conformational Spectrum

2008 ◽  
Vol 74 (23) ◽  
pp. 7431-7433 ◽  
Author(s):  
Mónica Martínez-Alonso ◽  
Nuria González-Montalbán ◽  
Elena García-Fruitós ◽  
Antonio Villaverde
Keyword(s):  
Escherichia Coli ◽  
Green Fluorescent Protein ◽  
Recombinant Proteins ◽  
Fluorescent Protein ◽  
Native Structure ◽  
Functional Quality ◽  
Soluble Aggregates ◽  
Recombinant Polypeptides ◽  
Green Fluorescent

ABSTRACT We have observed that a soluble recombinant green fluorescent protein produced in Escherichia coli occurs in a wide conformational spectrum. This results in differently fluorescent protein fractions in which morphologically diverse soluble aggregates abound. Therefore, the functional quality of soluble versions of aggregation-prone recombinant proteins is defined statistically rather than by the prevalence of a canonical native structure.

A Novel Approach To Investigate the Uptake and Internalization of Escherichia coli O157:H7 in Spinach Cultivated in Soil and Hydroponic Medium†

2009 ◽  
Vol 72 (7) ◽  
pp. 1513-1520 ◽  
Author(s):  
MANAN SHARMA ◽  
DAVID T. INGRAM ◽  
JITENDRA R. PATEL ◽  
PATRICIA D. MILLNER ◽  
XIAOLIN WANG ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Plasmid Vector ◽  
Green Fluorescent Protein Gene ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Novel Approach ◽  
Efficient Uptake ◽  
Green Fluorescent

Internalization of Escherichia coli O157:H7 into spinach plants through root uptake is a potential route of contamination. ATn7-based plasmid vector was used to insert a green fluorescent protein gene into the attTn7 site in the E. coli chromosome. Three green fluorescent protein–labeled E. coli inocula were used: produce outbreak O157:H7 strains RM4407 and RM5279 (inoculum 1), ground beef outbreak O157:H7 strain 86-24h11 (inoculum 2), and commensal strain HS (inoculum 3). These strains were cultivated in fecal slurries and applied at ca. 103 or 107 CFU/g to pasteurized soils in which baby spinach seedlings were planted. No E. coli was recovered by spiral plating from surface-sanitized internal tissues of spinach plants on days 0, 7, 14, 21, and 28. Inoculum 1 survived at significantly higher populations (P &lt; 0.05) in the soil than did inoculum 3 after 14, 21, and 28 days, indicating that produce outbreak strains of E. coli O157:H7 may be less physiologically stressed in soils than are nonpathogenic E. coli isolates. Inoculum 2 applied at ca. 107 CFU/ml to hydroponic medium was consistently recovered by spiral plating from the shoot tissues of spinach plants after 14 days (3.73 log CFU per shoot) and 21 days (4.35 log CFU per shoot). Fluorescent E. coli cells were microscopically observed in root tissues in 23 (21%) of 108 spinach plants grown in inoculated soils. No internalized E. coli was microscopically observed in shoot tissue of plants grown in inoculated soil. These studies do not provide evidence for efficient uptake of E. coli O157:H7 from soil to internal plant tissue.

scholarly journals Expression of green fluorescent protein (GFPuv) in Escherichia coli DH5-a, under different growth conditions

2004 ◽  
Vol 3 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Christina Vessoni Penna Thereza ◽  
Ishii Marina ◽  
de Souza Luciana.Cambricoli ◽  
Cholewa Olivia
Keyword(s):  
Escherichia Coli ◽  
Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Growth Conditions ◽  
Green Fluorescent
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