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Search results for: Fluorescence

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#33098689   2020/10/24 To Up

A mini-Tn5-derived transposon with reportable and selectable markers enables rapid generation and screening of insertional mutants in Gram-negative bacteria.

We re-engineered a classic tool for mutagenesis and gene expression studies in Gram-negative bacteria. Our modified Tn5-based transposon contains multiple features that allow rapid selection for mutants, direct quantification of gene expression, and straightforward cloning of the inactivated gene. The promoter-less gfp-km cassette provides selection and reporter assay depending on the activity of the promoter upstream of the transposon insertion site. The cat gene facilitates positive antibiotic selection for mutants, while the narrow R6Kγ replication origin forces transposition in recipient strains lacking the pir gene and enables cloning the transposon flanked with the disrupted gene from the chromosome. The suicide vector pCKD100, a plasmid that could be delivered into recipient cells through bi-parental mating or electroporation, harbors the modified transposon. We used the transposon to mutagenize Pectobacterium versatile KD100, Pseudumonas coronafaciens PC27R, and Escherichia coli 35150N. The fluorescence intensities of mutants expressing high GFP could be quantified and detected qualitatively. Transformation efficiency from conjugation ranged from 1600 to 1900 CFU ml . We sequenced the upstream flanking regions, identified the putative truncated genes, and demonstrated the restoration of the GFP phenotype through marker exchange. The mini-Tn5 transposon was also utilized to construct mutant library of P. versatile for forward genetic screens.
Eric S Nazareno, Bimala Acharya, C Korsi Dumenyo

1962 related Products with: A mini-Tn5-derived transposon with reportable and selectable markers enables rapid generation and screening of insertional mutants in Gram-negative bacteria.

1 mL400Tests25 mg100ug96T1 ml50 mg100 assays1000 tests

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#33098675   2020/10/24 To Up

Evaluation of the probiotic and functional potential of Lactobacillus agilis 32 isolated from pig manure.

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Shuiqin Shi, Baoyan Cheng, Bintao Gu, Tingting Sheng, Jian Tu, Ying Shao, Kezong Qi, Duoqi Zhou

1952 related Products with: Evaluation of the probiotic and functional potential of Lactobacillus agilis 32 isolated from pig manure.

5 G100.00 ul2.5 g10 mg25 mg50 ul500 Units100 ul 1 G1000 tests2.5 mg

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#33098593   2020/10/24 To Up

Dual Emission of a Free-Base 5-Oxaporphyrinium Cation from its cis- and trans-NH Tautomers.

Replacement of the  meso  methine carbon atoms of porphyrins with heteroatoms represents a powerful strategy for tuning their optical and electronic properties. In particular, 5-oxaporphyrin is an attractive target due to its importance as an intermediate in heme catabolism. In this work, we describe the synthesis and properties of a free-base 5-oxaporphyrinium cation, which was prepared by the ring-closure of a bilindione with trifluoromethanesulfonic anhydride. This free-base 5-oxaporphyrinium cation exhibits dual fluorescence originating from its unique NH tautomerism. In contrast to normal porphyrins, the  cis  form of the 5-oxaporphyrinium cation is more stable than the  trans  form due to the effective delocalization of its positive charge. We thus demonstrate here that  meso -modified  heteroporphyrins enable the manipulation of NH tautomerism in porphyrinic macrocycles.
Asahi Takiguchi, Seongsoo Kang, Norihito Fukui, Dongho Kim, Hiroshi Shinokubo

1118 related Products with: Dual Emission of a Free-Base 5-Oxaporphyrinium Cation from its cis- and trans-NH Tautomers.

50 mg100ug Lyophilized250 mg 5 G100 100ug Lyophilized500gm 100ul1 g0.25 mg20 ul100ug

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#33098586   2020/10/24 To Up

Beyond the patch-clamp resolution:functional activity of non-electrogenic vacuolar NHX proton/potassium antiporters and inhibition by phosphoinositides.

We combined the patch-clamp technique with ratiometric fluorescence imaging using the proton-responsive BCECF dye as a luminal probe. Upon application of a steep cytosol-directed K gradient in Arabidopsis mesophyll vacuoles, a strong and reversible acidification of the vacuolar lumen was detected, while no associated electrical currents were observed, in agreement with electroneutral cation/H exchange. Our data show that this acidification was generated by NHX antiport activity, since: it did not distinguish between K and Na ions; it was sensitive to the NHX inhibitor benzamil; and it was completely absent in vacuoles from nhx1 nhx2 double knockout plants. Our data further show that NHX activity could be reversed, was voltage independent and specifically impaired by the low-abundance signaling lipid PI(3,5)P , which may regulate salt accumulation in plants by acting as a common messenger to coordinately shut down secondary active carriers responsible for cation and anion uptake inside the vacuole. Finally, we developed a theory based on thermodynamics, which supports the data obtained by our novel experimental approach. This work, therefore, represents a proof of principle that can be applied to the study of proton-dependent exchangers from plants and animals, which are barely detectable using conventional techniques.
Antonella Gradogna, Joachim Scholz-Starke, José M Pardo, Armando Carpaneto

2996 related Products with: Beyond the patch-clamp resolution:functional activity of non-electrogenic vacuolar NHX proton/potassium antiporters and inhibition by phosphoinositides.

48 assays 96 assays 0.1ml (1mg/ml)48 assays 96 assays 48 assays48 assays 96 assays

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#33098572   2020/10/24 To Up

6-phenylpyrrolocytosine as a fluorescent probe to examine nucleotide flipping catalyzed by a DNA repair protein.

Cellular exposure to tobacco-specific nitrosamines causes formation of promutagenic O -[4-oxo-4-(3-pyridyl)but-1-yl]guanine (O -POB-G) and O -methylguanine (O -Me-G) adducts in DNA. These adducts can be directly repaired by O -alkylguanine-DNA alkyltransferase (AGT). Repair begins by flipping the damaged base out of the DNA helix. AGT binding and base-flipping have been previously studied using pyrrolocytosine as a fluorescent probe paired to the O -alkylguanine lesion, but low fluorescence yield limited the resolution of steps in the repair process. Here, we utilize the highly fluorescent 6-phenylpyrrolo-2'-deoxycytidine (6-phenylpyrrolo-C) to investigate AGT-DNA interactions. Synthetic oligodeoxynucleotide duplexes containing O -POB-G and O -Me-G adducts were placed within the CpG sites of codons 158, 245, and 248 of the p53 tumor suppressor gene and base-paired to 6-phenylpyrrolo-C in the opposite strand. Neighboring cytosine was either unmethylated or methylated. Stopped-flow fluorescence measurements were performed by mixing the DNA duplexes with C145A or R128G AGT variants. We observe a rapid, two-step, nearly irreversible binding of AGT to DNA followed by two slower steps, one of which is base-flipping. Placing 5-methylcytosine immediately 5' to the alkylated guanosine causes a reduction in rate constant of nucleotide flipping. O -POB-G at codon 158 decreased the base flipping rate constant by 3.5-fold compared with O -Me-G at the same position. A similar effect was not observed at other codons.
Delshanee Kotandeniya, Melanie S Rogers, Jenna Fernandez, Sreenivas Kanugula, Robert H E Hudson, Freddys Rodriguez, John D Lipscomb, Natalia Tretyakova

1554 related Products with: 6-phenylpyrrolocytosine as a fluorescent probe to examine nucleotide flipping catalyzed by a DNA repair protein.

10 1 mg10reactions 100ug Lyophilized1 kit(96 Wells)1 kit100ug Lyophilized

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#33098375   2020/10/24 To Up

Real-Time Visual Monitoring of Kinetically Controlled Self-Assembly.

The construction of artificial structures through hierarchical self-assembly via noncovalent interactions, as well as the monitoring during self-assembly process, play significant roles in dynamic supramolecular chemistry. We managed complex dynamics of newly designed chiral N,N'-diphenyl-dihydrodibenzo[a,c]phenazines derivatives (S)/(R)-DPAC that involved different assemblies with distinct optical and morphological characteristics. With the ratiometric fluorescence originated from the vibration-induced emission (VIE) feature, the self-assembly process from the kinetic traps to the thermodynamic equilibrium state can be real-timely monitored by optical spectrometry effectively. Besides, accompanying with the morphology transformation from particles to nanobricks, the self-assemblies can induce strong circularly polarized luminescence (CPL) with glum = 1.6×10-2. The excited-state characteristic of the self-assemblies offered significant approaches to investigate the relationship between molecular aggregation and conformational change, allowing effective monitoring of the sophisticated supramolecular self-assembly process.
Zizhao Huang, Tao Jiang, Jie Wang, Xiang Ma, He Tian

1534 related Products with: Real-Time Visual Monitoring of Kinetically Controlled Self-Assembly.

25250 ea25252525252525252525

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#33098175   2020/10/23 To Up

Receptor GPR91 contributes to voiding function and detrusor relaxation mediated by succinate.

Succinate activates the receptor GPR91 identified in the bladder. The present study aims to unravel the mechanisms of bladder relaxation by succinate and how the receptor is involved in structural and functional changes of the bladder.
Abubakr Mossa, Monica Velasquez-Flores, Philippe G Cammisotto, Lysanne Campeau

2637 related Products with: Receptor GPR91 contributes to voiding function and detrusor relaxation mediated by succinate.

50 ug 0.1 mg100ug100ug100ul50 ug 1 ml100.00 ul100ul100ug100ug100ug

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#33098061   2020/10/23 To Up

Does Variability Affect the Performance of Front-Face Fluorescence Spectroscopy? A Study Case on Commercial Lebanese Olive Oil.

The potential of front-face fluorescence spectroscopy coupled with chemometric techniques, namely multiple linear regression (MLR) applied on parallel factor (PARAFAC) scores and partial least squares (PLS), was tested on Lebanese olive oil samples possessing natural variability within their chemical parameters. Ninety-six olive oil samples have been harvested at different dates and from two seasons, processed using different extraction methods, collected from different altitudes and other factors that can increase the variability of the samples' chemical composition. Fluorescence excitation-emission matrices (EEM) of the collected samples were measured, and the relationship between them and the chemical parameters was examined. Twenty-two MLR regression models based on PARAFAC scores were generated, the majority of which showed a good correlation coefficient (R > 0.7 for ten predicted variables). A second model using PLS on the unfolded EEM was also conducted to improve the regression and to assess if it can handle the variability in hand. However, similar results, with a slight improvement over the MLR model, were obtained. In a non-experimental design, such variability may hinder the potentials of front-face fluorescence; however average to good MLR and PLS models were obtained, predicting the Lebanese olive oil deterioration quality parameters and fatty acid content.
Omar H Dib, Jad Rizkalah, Rita Yaacoub, Hussein Dib, Nathalie Locquet, Luc Eveleigh, Christophe B Y Cordella, Ali Bassal

2908 related Products with: Does Variability Affect the Performance of Front-Face Fluorescence Spectroscopy? A Study Case on Commercial Lebanese Olive Oil.

1 kit

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