7 research outputs found
Purification and characterization of a thermoalkaline, cellulase free thermostable xylanase from a newly isolated Anoxybacillus sp. Ip-C from hot spring of Ladakh
An alkaline, highly thermostable cellulase free xylanase was purified from a thermophilic Anoxybacillus sp. Ip-C, newly isolated from hot spring of Ladakh. The enzyme was purified using ammonia sulphate precipitation followed by Sephadex G-75. The molecular weight of the xylanase was about 45 kDa, as analyzed by SDS-PAGE. The enzyme had optimum activity at pH 9.0 and 70ĂâĂÂșC temperature; the enzyme retained 90% of its original activity for 96 hrs at 70 ĂâĂÂșC. Vmax and Km of the enzyme were found to be 13.5 ĂâĂ”mol min-1 mg-1 protein and 4.59 mg ml-1, respectively. Metal ions, Ca+2, Fe+2 and Mg+2 highly enhance the enzyme activity to 122.45, 119.06 and 118.98% respectively; whereas SDS and Hg+2 completely inhibit (0 U/ml) the enzyme activity. TLC analysis of enzymatic hydrolysis products showed that this xylanase is an endoxylanase, and generates xylooligosaccharides. Thus, it provides a potential thermostable alkaline xylanase for industrial applications
A rhodamine derivative as a "lock" and SCN- as a "key": Visible light excitable SCN- sensing in living cells
A visible light excitable rhodamine based probe operates as a SCN - selective fluorescent "turn-on" sensor for living cell imaging with a detection limit of 0.01 ΌM, which is much lower than the normal SCN- level in the human body. A "lock" and "key" model has been proposed to explain the fluorescence enhancement of the rhodamine probe in the presence of SCN-. © 2013 The Royal Society of Chemistry
Ratiometric fluorescence sensing and intracellular imaging of Al3+ ion driven by an intramolecular excimer formation of a pyrimidine-pyrene scaffold
Nickel(II)-Induced Excimer Formation of a Naphthalene-Based Fluorescent Probe for Living Cell Imaging
Ni<sup>2+</sup>-induced intramolecular excimer formation
of a naphthalene-based
novel fluorescent probe, 1-[(naphthalen-3-yl)Âmethylthio]-2-[(naphthalen-6-yl)Âmethylthio]Âethane
(<b>L</b>), has been investigated for the first time and nicely
demonstrated by excitation spectra, a fluorescence lifetime experiment,
and <sup>1</sup>H NMR titration. The addition of Ni<sup>2+</sup> to
a solution of <b>L</b> (DMSO:water = 1:1, v/v; λ<sub>em</sub> = 345 nm, λ<sub>ex</sub> = 280 nm) quenched its monomer emission,
with subsequent enhancement of the excimer intensity (at 430 nm) with
an isoemissive point at 381 nm. The fluorescence lifetime of free <b>L</b> (0.3912 ns) is much lower than that of the nickelÂ(2+) complex
(1.1329 ns). <b>L</b> could detect Ni<sup>2+</sup> as low as
1 Ă 10<sup>â6</sup> M with a fairly strong binding constant,
2.0 Ă 10<sup>4</sup> M<sup>â1</sup>. Ni<sup>2+</sup>-contaminated
living cells of plant origin could be imaged using a fluorescence
microscope
Nickel(II)-Induced Excimer Formation of a Naphthalene-Based Fluorescent Probe for Living Cell Imaging
Ni<sup>2+</sup>-induced intramolecular excimer formation
of a naphthalene-based
novel fluorescent probe, 1-[(naphthalen-3-yl)Âmethylthio]-2-[(naphthalen-6-yl)Âmethylthio]Âethane
(<b>L</b>), has been investigated for the first time and nicely
demonstrated by excitation spectra, a fluorescence lifetime experiment,
and <sup>1</sup>H NMR titration. The addition of Ni<sup>2+</sup> to
a solution of <b>L</b> (DMSO:water = 1:1, v/v; λ<sub>em</sub> = 345 nm, λ<sub>ex</sub> = 280 nm) quenched its monomer emission,
with subsequent enhancement of the excimer intensity (at 430 nm) with
an isoemissive point at 381 nm. The fluorescence lifetime of free <b>L</b> (0.3912 ns) is much lower than that of the nickelÂ(2+) complex
(1.1329 ns). <b>L</b> could detect Ni<sup>2+</sup> as low as
1 Ă 10<sup>â6</sup> M with a fairly strong binding constant,
2.0 Ă 10<sup>4</sup> M<sup>â1</sup>. Ni<sup>2+</sup>-contaminated
living cells of plant origin could be imaged using a fluorescence
microscope