Use of Green Fluorescent Protein To Tag and Investigate Gene Expression in Marine Bacteria

1998 ◽  
Vol 64 (7) ◽  
pp. 2554-2559 ◽  
Author(s):  
Serina Stretton ◽  
Somkiet Techkarnjanaruk ◽  
Alan M. McLennan ◽  
Amanda E. Goodman
Keyword(s):  
Gene Expression ◽  
Green Fluorescent Protein ◽  
Marine Bacteria ◽  
Laser Scanning ◽  
Fluorescent Protein ◽  
Single Cells ◽  
Bacterial Species ◽  
Epifluorescence Microscopy ◽  
Broad Host Range ◽  
Green Fluorescent

ABSTRACT Two broad-host-range vectors previously constructed for use in soil bacteria (A. G. Matthysse, S. Stretton, C. Dandie, N. C. McClure, and A. E. Goodman, FEMS Microbiol. Lett. 145:87–94, 1996) were assessed by epifluorescence microscopy for use in tagging three marine bacterial species. Expression of gfp could be visualized in Vibrio sp. strain S141 cells at uniform levels of intensity from either the lac or thenpt-2 promoter, whereas expression of gfp could be visualized in Psychrobacter sp. strain SW5H cells at various levels of intensity only from the npt-2 promoter. Green fluorescent protein (GFP) fluorescence was not detected in the third species, Pseudoalteromonas sp. strain S91, when thegfp gene was expressed from either promoter. A new mini-Tn10-kan-gfp transposon was constructed to investigate further the possibilities of fluorescence tagging of marine bacteria. Insertion of mini-Tn10-kan-gfp generated random stable mutants at high frequencies with all three marine species. With this transposon, strongly and weakly expressed S91 promoters were isolated. Visualization of GFP by epifluorescence microscopy was markedly reduced when S91 (mini-Tn10-kan-gfp) cells were grown in rich medium compared to that when cells were grown in minimal medium. Mini-Tn10-kan-gfp was used to create an S91 chitinase-negative, GFP-positive mutant. Expression of the chi-gfp fusion was induced in cells exposed toN′-acetylglucosamine or attached to chitin particles. By laser scanning confocal microscopy, biofilms consisting of microcolonies of chi-negative, GFP+ S91 cells were found to be localized several microns from a natural chitin substratum. Tagging bacterial strains with GFP enables visualization of, as well as monitoring of gene expression in, living single cells in situ and in real time.

scholarly journals Construction of Self-Transmissible Green Fluorescent Protein-Based Biosensor Plasmids and Their Use for Identification of N-Acyl Homoserine-Producing Bacteria in Lake Sediments

2010 ◽  
Vol 76 (18) ◽  
pp. 6119-6127 ◽  
Author(s):  
Putthapoom Lumjiaktase ◽  
Claudio Aguilar ◽  
Tom Battin ◽  
Kathrin Riedel ◽  
Leo Eberl
Keyword(s):  
Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Bacterial Species ◽  
Natural Habitat ◽  
Homoserine Lactone ◽  
Signal Molecules ◽  
Broad Host Range ◽  
Construction Of Self ◽  
Green Fluorescent ◽  
The Impact

ABSTRACT Many bacteria utilize quorum sensing (QS) systems to communicate with each other by means of the production, release, and response to signal molecules. N-Acyl homoserine lactone (AHL)-based QS systems are particularly widespread among the Proteobacteria, in which they regulate various functions. It has become evident that AHLs can also serve as signals for interspecies communication. However, knowledge on the impact of AHLs for the ecology of bacteria in their natural habitat is scarce, due mainly to the lack of tools that allow the study of QS in bacterial communities in situ. Here, we describe the construction of self-mobilizable green fluorescent protein (GFP)-based AHL sensors that utilize the conjugation and replication properties of the broad-host-range plasmid RP4. We show that these novel AHL sensor plasmids can be easily transferred to different bacterial species by biparental mating and that they give rise to green fluorescent cells in case the recipient is an AHL producer. We also demonstrate that these sensor plasmids are capable of self-spreading within mixed biofilms and are a suitable tool for the identification of AHL-producing bacteria in lake sediment.

Use of Green Fluorescent Protein Expressing Salmonella Stanley To Investigate Survival, Spatial Location, and Control on Alfalfa Sprouts

2001 ◽  
Vol 64 (12) ◽  
pp. 1891-1898 ◽  
Author(s):  
MEGHA GANDHI ◽  
SHERENE GOLDING ◽  
SIMA YARON ◽  
KARL R. MATTHEWS
Keyword(s):  
Green Fluorescent Protein ◽  
Laser Scanning ◽  
Fluorescent Protein ◽  
Plasmid Stability ◽  
Constitutive Expression ◽  
Epifluorescence Microscopy ◽  
Initial Population ◽  
Alfalfa Sprouts ◽  
Green Fluorescent ◽  
Alfalfa Seeds

Laser scanning confocal microscopy (LSCM) was used to observe the interaction of Salmonella Stanley with alfalfa sprouts. The green fluorescent protein (gfp) gene was integrated into the chromosome of Salmonella Stanley for constitutive expression, thereby eliminating problems of plasmid stability and loss of signal. Alfalfa seeds were inoculated by immersion in a suspension of Salmonella Stanley (ca. 107 CFU/ml) for 5 min at 22°C. Epifluorescence microscopy demonstrated the presence of target bacteria on the surface of sprouts. LSCM demonstrated bacteria present at a depth of 12μm within intact sprout tissue. An initial population of ca. 104 CFU/g seed increased to 7.0 log CFU/g during a 24-h germination period and then decreased to 4.9 log CFU/g during a 144-h sprouting period. Populations of Salmonella Stanley on alfalfa seeds decreased from 5.2 to 4.1 log CFU/g and from 5.2 to 2.8 log CFU/g for seeds stored 60 days at 5 and 22°C, respectively. The efficacy of 100, 200, 500, or 2,000 ppm chlorine in killing Salmonella Stanley associated with sprouts was determined. Treatment of sprouts in 2,000 ppm chlorine for 2 or 5 min caused a significant reduction in populations of Salmonella Stanley. Influence of storage on Salmonella Stanley populations was investigated by storing sprouts 4 days at 4°C. The initial population (7.76 log CFU/g) of Salmonella Stanley on mature sprouts decreased (7.67 log CFU/g) only slightly. Cross-contamination during harvest was investigated by harvesting contaminated sprouts, then directly harvesting noncontaminated sprouts. This process resulted in the transfer of ca. 105 CFU/g Salmonella Stanley to the noncontaminated sprouts.

scholarly journals Use of Green Fluorescent Protein Color Variants Expressed on Stable Broad-Host-Range Vectors to Visualize Rhizobia Interacting with Plants

2000 ◽  
Vol 13 (11) ◽  
pp. 1163-1169 ◽  
Author(s):  
Nico Stuurman ◽  
Cristina Pacios Bras ◽  
Helmi R. M. Schlaman ◽  
André H. M. Wijfjes ◽  
Guido Bloemberg ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Host Range ◽  
Laser Scanning ◽  
Fluorescent Protein ◽  
Yellow Fluorescent Protein ◽  
Confocal Laser ◽  
Broad Host Range ◽  
Enhanced Yellow Fluorescent Protein ◽  
Green Fluorescent ◽  
Color Variants

We developed two sets of broad-host-range vectors that drive expression of the green fluorescent protein (GFP) or color variants thereof (henceforth collectively called autofluorescent proteins [AFPs]) from the lac promoter. These two sets are based on different replicons that are maintained in a stable fashion in Escherichia coli and rhizobia. Using specific filter sets or a dedicated confocal laser scanning microscope setup in which emitted light is split into its color components through a prism, we were able to unambiguously identify bacteria expressing enhanced cyan fluorescent protein (ECFP) or enhanced yellow fluorescent protein (EYFP) in mixtures of the two. Clearly, these vectors will be valuable tools for competition, cohabitation, and rescue studies and will also allow the visualization of interactions between genetically marked bacteria in vivo. Here, we used these vectors to visualize the interaction between rhizobia and plants. Specifically, we found that progeny from different rhizobia can be found in the same nodule or even in the same infection thread. We also visualized movements of bacteroids within plant nodule cells.

Postharvest Handling Conditions Affect Internalization of Salmonella in Baby Spinach during Washing

2013 ◽  
Vol 76 (7) ◽  
pp. 1145-1151 ◽  
Author(s):  
VICENTE M. GÓMEZ-LÓPEZ ◽  
ALICIA MARÍN ◽  
ANA ALLENDE ◽  
LARRY R. BEUCHAT ◽  
MARÍA I. GIL
Keyword(s):  
Green Fluorescent Protein ◽  
Laser Scanning ◽  
Fluorescent Protein ◽  
Negative Temperature ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Temperature Differential ◽  
Postharvest Handling ◽  
Green Fluorescent ◽  
Spinach Leaves

Internalization of foodborne pathogens in fruits and vegetables is an increasing safety concern. The aim of this research was to assess the potential for internalization of an enteric pathogen (Salmonella enterica serotype Typhimurium) in a leafy vegetable (baby spinach) during washing as influenced by three postharvest handling conditions: (i) illumination, (ii) negative temperature differential, and (iii) relative humidity (RH). To compare these potential postharvest handling conditions, leaves were exposed to different levels of illumination (0, 1,000, and 2,000 lx), temperature differential (5, 11, 14, 20, and 26uC), and RH (99, 85, and 74%) for a short time before or during washing. Washing of baby spinach was carried out in water containing green fluorescent protein–tagged Salmonella Typhimurium (6.5 log CFU/ml) at 5uC for 2 min, followed by surface disinfection with chlorine (10,000 μg/ml) for 1 min, two rinses in water for 10 s, and spin drying for 15 s. Internalization was assessed by enumerating the pathogen on Salmonella-Shigella agar and by confocal laser scanning microscopy. Illumination of spinach leaves before and during washing and a negative temperature differential during washing did not significantly (P > 0.05) increase the number of internalized bacteria. However, exposure of leaves to low-RH conditions before washing, which reduced the tissue water content, decreased internalization of Salmonella compared with internalization in baby spinach exposed to high RH (P ≤ 0.05). Green fluorescent protein–tagged Salmonella Typhimurium was visualized by confocal laser scanning microscopy at a depth of up to 30 μm beneath the surface of spinach leaves after exposure to a high inoculum level (8 log CFU/ml) for an extended time (2 h). Results show that internalization of Salmonella into baby spinach leaves can occur but can be minimized under specific postharvest handling conditions such as low RH.

Green Fluorescent Protein: A Tool for Gene Expression and Cell Biology in Mycobacteria

2003 ◽  
pp. 245-260
Author(s):  
Laura E. Via ◽  
Subramanian Dhandayuthapani ◽  
Dusanka Deretic ◽  
V. Deretic
Keyword(s):  
Gene Expression ◽  
Green Fluorescent Protein ◽  
Cell Biology ◽  
Fluorescent Protein ◽  
Protein A ◽  
Green Fluorescent

Cryptococcus neoformans Differential Gene Expression Detected In Vitro and In Vivo with Green Fluorescent Protein

1999 ◽  
Vol 67 (4) ◽  
pp. 1812-1820
Author(s):  
Maurizio del Poeta ◽  
Dena L. Toffaletti ◽  
Thomas H. Rude ◽  
Sara D. Sparks ◽  
Joseph Heitman ◽  
...  
Keyword(s):  
Gene Expression ◽  
Green Fluorescent Protein ◽  
Cryptococcus Neoformans ◽  
Differential Gene Expression ◽  
Fluorescent Protein ◽  
Differential Gene ◽  
Green Fluorescent

Migration of Salmonella Enteritidis Phage Type 30 through Almond Hulls and Shells

2008 ◽  
Vol 71 (2) ◽  
pp. 397-401 ◽  
Author(s):  
MICHELLE D. DANYLUK ◽  
MARIA T. BRANDL ◽  
LINDA J. HARRIS
Keyword(s):  
Green Fluorescent Protein ◽  
Laser Scanning ◽  
Salmonella Enteritidis ◽  
Fluorescent Protein ◽  
Phage Type ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Aqueous Environment ◽  
Serovar Typhimurium ◽  
Green Fluorescent

The ability of Salmonella to migrate from an external aqueous environment through the almond hull and shell, and to colonize the kernel, was evaluated in two ways. First, the outer surface of shell halves from five varieties of almonds that differed in shell hardness were placed in contact with a suspension of Salmonella enterica serovar Enteritidis phage type 30 for 24hat24°C. Salmonella Enteritidis was isolated from the inside of these almond shells in 46 and 100% of the samples, by direct swabbing of the inner surface of the shell and by enrichment from the swab, respectively. These findings suggested that hardness of the shell is not a significant factor in the migration of the pathogen through that tissue. In addition, both motile and nonmotile strains of S. enterica serovar Typhimurium migrated through the almond shells to the same extent under the conditions of this assay, indicating that bacterial migration through the wet shell may be a passive process. Second, whole almonds (intact hull, shell, and kernel) were soaked for 24 to 72 h at 24°C in a suspension of Salmonella Enteritidis phage type 30 labeled with the green fluorescent protein. Green fluorescent protein–labeled Salmonella cells were observed on the outer and inner surfaces of both the almond hull and shell, and on the kernel, by confocal laser scanning microscopy. Our data provide direct evidence that wet conditions allow for Salmonella migration through the hull and shell and onto the almond kernel, thus providing a means by which almond kernels may become contaminated in the field.

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