scholarly journals A green fluorescent protein solubility screen in E. coli reveals domain boundaries of the GTP-binding domain in the P element transposase

2010 ◽  
Vol 19 (11) ◽  
pp. 2210-2218 ◽  
Author(s):  
Alex Sabogal ◽  
Donald C. Rio
2009 ◽  
Vol 72 (7) ◽  
pp. 1513-1520 ◽  
Author(s):  
MANAN SHARMA ◽  
DAVID T. INGRAM ◽  
JITENDRA R. PATEL ◽  
PATRICIA D. MILLNER ◽  
XIAOLIN WANG ◽  
...  

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 < 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.


2020 ◽  
Vol 8 (7) ◽  
pp. 1051 ◽  
Author(s):  
Aleksandar Božić ◽  
Robin C. Anderson ◽  
Tawni L. Crippen ◽  
Christina L. Swaggerty ◽  
Michael E. Hume ◽  
...  

Numerous Salmonella enterica serovars can cause disease and contamination of animal-produced foods. Oligosaccharide-rich products capable of blocking pathogen adherence to intestinal mucosa are attractive alternatives to antibiotics as these have potential to prevent enteric infections. Presently, a wood-derived prebiotic composed mainly of glucose-galactose-mannose-xylose oligomers was found to inhibit mannose-sensitive binding of select Salmonella Typhimurium and Escherichia coli strains when reacted with Saccharomyces boulardii. Tests for the ability of the prebiotic to prevent binding of a green fluorescent protein (GFP)-labeled S. Typhimurium to intestinal porcine epithelial cells (IPEC-J2) cultured in vitro revealed that prebiotic-exposed GFP-labeled S. Typhimurium bound > 30% fewer individual IPEC-J2 cells than did GFP-labeled S. Typhimurium having no prebiotic exposure. Quantitatively, 90% fewer prebiotic-exposed GFP-labeled S. Typhimurium cells were bound per individual IPEC-J2 cell compared to non-prebiotic exposed GFP-labeled S. Typhimurium. Comparison of invasiveness of S. Typhimurium DT104 against IPEC-J2 cells revealed greater than a 90% decrease in intracellular recovery of prebiotic-exposed S. Typhimurium DT104 compared to non-exposed controls (averaging 4.4 ± 0.2 log10 CFU/well). These results suggest compounds within the wood-derived prebiotic bound to E. coli and S. Typhimurium-produced adhesions and in the case of S. Typhimurium, this adhesion-binding activity inhibited the binding and invasion of IPEC-J2 cells.


2006 ◽  
Vol 72 (12) ◽  
pp. 7607-7613 ◽  
Author(s):  
Andrew C. Tolonen ◽  
Gregory B. Liszt ◽  
Wolfgang R. Hess

ABSTRACT Prochlorococcus is the smallest oxygenic phototroph yet described. It numerically dominates the phytoplankton community in the mid-latitude oceanic gyres, where it has an important role in the global carbon cycle. The complete genomes of several Prochlorococcus strains have been sequenced, revealing that nearly half of the genes in each genome are of unknown function. Genetic methods, such as reporter gene assays and tagged mutagenesis, are critical to unveiling the functions of these genes. Here, we describe conditions for the transfer of plasmid DNA into Prochlorococcus strain MIT9313 by interspecific conjugation with Escherichia coli. Following conjugation, E. coli bacteria were removed from the Prochlorococcus cultures by infection with E. coli phage T7. We applied these methods to show that an RSF1010-derived plasmid will replicate in Prochlorococcus strain MIT9313. When this plasmid was modified to contain green fluorescent protein, we detected its expression in Prochlorococcus by Western blotting and cellular fluorescence. Further, we applied these conjugation methods to show that a mini-Tn5 transposon will transpose in vivo in Prochlorococcus. These genetic advances provide a basis for future genetic studies with Prochlorococcus, a microbe of ecological importance in the world's oceans.


2017 ◽  
Vol 83 (8) ◽  
Author(s):  
Shireen Kotay ◽  
Weidong Chai ◽  
William Guilford ◽  
Katie Barry ◽  
Amy J. Mathers

ABSTRACT There have been an increasing number of reports implicating Gammaproteobacteria as often carrying genes of drug resistance from colonized sink traps to vulnerable hospitalized patients. However, the mechanism of transmission from the wastewater of the sink P-trap to patients remains poorly understood. Herein we report the use of a designated hand-washing sink lab gallery to model dispersion of green fluorescent protein (GFP)-expressing Escherichia coli from sink wastewater to the surrounding environment. We found no dispersion of GFP-expressing E. coli directly from the P-trap to the sink basin or surrounding countertop with coincident water flow from a faucet. However, when the GFP-expressing E. coli cells were allowed to mature in the P-trap under conditions similar to those in a hospital environment, a GFP-expressing E. coli-containing putative biofilm extended upward over 7 days to reach the strainer. This subsequently resulted in droplet dispersion to the surrounding areas (<30 in.) during faucet operation. We also demonstrated that P-trap colonization could occur by retrograde transmission along a common pipe. We postulate that the organisms mobilize up to the strainer from the P-trap, resulting in droplet dispersion rather than dispersion directly from the P-trap. This work helps to further define the mode of transmission of bacteria from a P-trap reservoir to a vulnerable hospitalized patient. IMPORTANCE Many recent reports demonstrate that sink drain pipes become colonized with highly consequential multidrug-resistant bacteria, which then results in hospital-acquired infections. However, the mechanism of dispersal of bacteria from the sink to patients has not been fully elucidated. Through establishment of a unique sink gallery, this work found that a staged mode of transmission involving biofilm growth from the lower pipe to the sink strainer and subsequent splatter to the bowl and surrounding area occurs rather than splatter directly from the water in the lower pipe. We have also demonstrated that bacterial transmission can occur via connections in wastewater plumbing to neighboring sinks. This work helps to more clearly define the mechanism and risk of transmission from a wastewater source to hospitalized patients in a world with increasingly antibiotic-resistant bacteria that can thrive in wastewater environments and cause infections in vulnerable patients.


2013 ◽  
Vol 80 (4) ◽  
pp. 1477-1481 ◽  
Author(s):  
Karina Klevanskaa ◽  
Nadja Bier ◽  
Kerstin Stingl ◽  
Eckhard Strauch ◽  
Stefan Hertwig

ABSTRACTAn efficient electroporation procedure forVibrio vulnificuswas designed using the new cloning vector pVv3 (3,107 bp). Transformation efficiencies up to 2 × 106transformants per μg DNA were achieved. The vector stably replicated in bothV. vulnificusandEscherichia coliand was also successfully introduced intoVibrio parahaemolyticusandVibrio cholerae. To demonstrate the suitability of the vector for molecular cloning, the green fluorescent protein (GFP) gene and thevvhBAhemolysin operon were inserted into the vector and functionally expressed inVibrioandE. coli.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Lia Ooi ◽  
Lee Yook Heng ◽  
Asmat Ahmad

Green fluorescent protein (GFP) is suitable as a toxicity sensor due to its ability to work alone without cofactors or substrates. Its reaction with toxicants can be determined with fluorometric approaches. GFP mutant gene (C48S/S147C/Q204C/S65T/Q80R) is used because it has higher sensitivity compared to others GFP variants. A novel sodium dodecyl sulfate (SDS) toxicity detection biosensor was built by immobilizing GFP expressingEscherichia coliink-Carrageenan matrix. Cytotoxicity effect took place in the toxicity biosensor which leads to the decrease in the fluorescence intensity. The fabricatedE. coliGFP toxicity biosensor has a wide dynamic range of 4–100 ppm, with LOD of 1.7 ppm. Besides, it possesses short response time (<1 min), high reproducibility (0.76% RSD) and repeatability (0.72% RSD,R2>0.98), and long-term stability (46 days).E. coliGFP toxicity biosensor has been applied to detect toxicity induced by SDS in tap water, river water, and drinking water. High recovery levels of SDS indicated the applicability ofE. coliGFP toxicity biosensor in real water samples toxicity evaluation.


2006 ◽  
Vol 69 (2) ◽  
pp. 276-281 ◽  
Author(s):  
T. P. OSCAR ◽  
K. DULAL ◽  
D. BOUCAUD

The green fluorescent protein (GFP) of the jellyfish Aequorea victoria has been widely used as a biomarker and has potential for use in developing predictive models for growth of pathogens on naturally contaminated food. However, constitutive production of GFP can reduce growth of transformed strains. Consequently, a high-copy plasmid with gfp under the control of a tetracycline-inducible promoter (pTGP) was constructed. The plasmid was first introduced into a tetracycline-resistant strain of Escherichia coli K-12 to propagate it for subsequent transformation of tetracycline-resistant strains of Salmonella. In contrast to transformed E. coli K-12, which only fluoresced in response to tetracycline, transformed Salmonella fluoresced maximally without tetracycline induction of gfp. Although pTGP did not function as intended in Salmonella, growth of parent and GFP E. coli K-12 was compared to test the hypothesis that induction of GFP production reduced growth. Although GFP production was not induced during growth on sterile chicken in the absence of tetracycline, maximum specific growth rate (μmax) of GFP E. coli K-12 was reduced 40 to 50% (P &lt; 0.05) at 10, 25, and 40°C compared with the parent strain. When growth of parent and GFP strains of E. coli K-12 was compared in sterile broth at 40°C, μmax and maximum population density of the GFP strain were reduced (P &lt; 0.05) to the same extent (50 to 60%) in the absence and presence of tetracycline. These results indicated that transformation reduced growth of E. coli K-12 independent of gfp induction. Thus, use of a low-copy plasmid or insertion of gfp into the chromosome may be required to construct valid strains for development of predictive models for growth of pathogens on naturally contaminated food.


1998 ◽  
Vol 180 (5) ◽  
pp. 1296-1304 ◽  
Author(s):  
Xuan-chuan Yu ◽  
Anthony H. Tran ◽  
Qin Sun ◽  
William Margolin

ABSTRACT Escherichia coli cell division protein FtsK is a homolog of Bacillus subtilis SpoIIIE and appears to act late in the septation process. To determine whether FtsK localizes to the septum, we fused three N-terminal segments of FtsK to green fluorescent protein (GFP) and expressed them in E. colicells. All three segments were sufficient to target GFP to the septum, suggesting that as little as the first 15% of the protein is a septum-targeting domain. Localized fluorescence was detectable only in cells containing a visible midcell constriction, suggesting that FtsK targeting normally occurs only at a late stage of septation. The largest two FtsK-GFP fusions were able at least partially to complement the ftsK44 mutation in trans, suggesting that the N- and C-terminal domains are functionally separable. However, overproduction of FtsK-GFP resulted in a late-septation phenotype similar to that of ftsK44, with fluorescent dots localized at the blocked septa, suggesting that high levels of the N-terminal domain may still localize but also inhibit FtsK activity. Interestingly, under these conditions fluorescence was also sometimes localized as bands at potential division sites, suggesting that FtsK-GFP is capable of targeting very early. In addition, FtsK-GFP localized to potential division sites in cephalexin-induced andftsI mutant filaments, further supporting the idea that FtsK-GFP can target early, perhaps by recognizing FtsZ directly. This hypothesis was supported by the failure of FtsK-GFP to localize inftsZ mutant filaments. In ftsK44 mutant filaments, FtsA and FtsZ were usually localized to potential division sites between the blocked septa. When the ftsK44 mutation was incorporated into the FtsK-GFP fusions, localization to midcell ranged between very weak and undetectable, suggesting that the FtsK44 mutant protein is defective in targeting the septum.


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