Enzymatic transformation of nitro-aromatic compounds by a flavin-free NADH azoreductase from Lysinibacillus sphaericus.

Azo dyes and nitro-aromatic compounds are the largest group of pollutants released in the environment as industrial wastes. They create serious health and environmental problems. Azoreductases catalyze the reduction of azo dyes and nitro compounds to their respective amines. AN azoreductase was purified up to 12-fold from Lysinibacillus sphaericus using ion-exchange and size exclusion chromatography. It was optimally active at pH 7.4 and 75 °C. It was stable at 70 °C for 30 min. The purified enzyme utilized NADH rather than NADPH as an electron donor to reduce substrates. The molecular weight of the purified enzyme was ~29 kDa. The enzyme also acted as nitroreductase and could selectively reduce the nitro group of 2-nitrophenol, 4-nitrobenzoic acid, 2-nitro-benzaldehyde and 3-nitrophenol. Reduction products of these compounds were identified by IR and NMR.

Properties of NAD (P) H azoreductase from alkaliphilic red bacteria Aquiflexum sp. DL6.

Azoreductase plays a key role in bioremediation and biotransformation of azo dyes. It initializes the reduction of azo bond in azo dye metabolism under aerobic or anaerobic conditions. In the present study, we isolated an alkaliphilic red-colored Aquiflexum sp. DL6 bacterial strain and identified by 16S rRNA method. We report nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate-dependent azoreductase purified from Aquiflexum sp. DL6 by a combination of ammonium sulfate precipitation and chromatography methods. The azoreductase was purified up to 30-fold with 37 % recovery. The molecular weight was found to be 80 kDa. The optimum activity was observed at pH 7.4 and temperature 60 °C with amaranth azo dye as a substrate. The thermal stability of azoreductase was up to 80 °C. The azoreductase has shown a wide range of substrate specificity, including azo dyes and nitro aromatic compounds. Metal ions have no significant inhibitory action on azoreductase activity. The apparent K m and V max values for amaranth azo dye were 1.11 mM and 30.77 U/mg protein respectively. This NAD (P) H azoreductase represents the first azoreductase to be characterized from alkaliphilic bacteria.

Proteomic profiling and interactome analysis of ER-positive/HER2/neu negative invasive ductal carcinoma of the breast: towards proteomics biomarkers.

Breast cancer, especially ER positive/HER2/neu negative IDC, is the predominant subtype of invasive ductal carcinoma. Although proteomic approaches have been used towards biomarker discovery in clinical breast cancer, ER positive/HER2/neu negative IDC is the least studied subtype. To discover biomarkers, as well as to understand the molecular events associated with disease progression of estrogen receptor positive/HER2/neu negative subtype of invasive ductal carcinoma, differential protein expression profiling was performed by using LC-MS(E) (MS at elevated energy). A total of 118 proteins were identified, of which 26 were differentially expressed. These identified proteins were functionally classified and their interactions and coexpression were analyzed by using bioinformatic tools PANTHER (Protein Analysis THrough Evolutionary Relationships) and STRING (Search Tool for the Retrieval of Interacting Genes). These proteins were found to be upregulated and were involved in cytoskeletal organization, calcium binding, and stress response. Interactions of annexin A5, actin, S100 A10, glyceraldehyde 3 phosphate dehydrogenase, superoxide dismutase 1, apolipoprotein, fibrinogen, and heat shock proteins were prominent. Differential expression of these proteins was validated by two-dimensional gel electrophoresis and Western blot analysis. The cluster of these proteins may serve as a signature profile for estrogen receptor positive/ HER2/neu negative subtype.

Analysis of AGE modified proteins and RAGE expression in HER2/neu negative invasive ductal carcinoma.

Cancer is associated with increased glycolysis and carbonyl stress. In view of this, AGE modified proteins were identified from clinical breast cancer tissue using 2DE-immunoblot and mass-spectrometry. These proteins were identified to be serotransferrin, fibrinogen gamma chain, glycerol-3-phosphate dehydrogenase, lactate dehydrogenase, annexin II, prohibitin and peroxiredoxin 6, which have established role in cancer. Further, RAGE expression and its downstream signaling proteins NADPH oxidase and NF-kB were studied. Role of these AGE modified proteins and RAGE signaling in breast cancer is discussed.

Mechanistic investigation of decolorization and degradation of reactive red 120 by Bacillus lentus BI377.

Bacillus lentus BI377, isolated from textile effluent-contaminated soil, was able to degrade 97% and 92% of Reactive Red 120 dye when 1200 and 1500 mg/l, respectively, of dye was added to nutrient broth (NB) at 35 °C within 12 h. UV-vis spectroscopy, GC-MS, FTIR and 1H NMR revealed the formation of catechol which may be further utilized by the bacterium via the TCA cycle, leading to complete mineralization. Structural analysis of metabolites in conjunction with enzyme activity studies confirmed the involvement of azoreductase, cytochrome P450 monooxygenase and other antioxidant enzymes. Decreases in total organic carbon and in biological and chemical oxygen demand suggest formation of low molecular weight metabolites that could be completely mineralized. These results suggest the potential use of B. lentus BI377 towards online treatment of textile dye effluents by using an appropriate bioreactor over a wide range of pH. This study opens-up a dependable and proficient way to use industrially viable non-pathogenic strains for biotransformation of carcinogenic dyes to ecofriendly compounds.

Decolorization and degradation of Disperse Blue 79 and Acid Orange 10, by Bacillus fusiformis KMK5 isolated from the textile dye contaminated soil.

The release of azo dyes into the environment is a concern due to coloration of natural waters and due to the toxicity, mutagenicity and carcinogenicity of the dyes and their biotransformation products. The dye degrading bacterial strain KMK 5 was isolated from the textile dyes contaminated soil of Ichalkaranji, Maharashtra, India. It was identified as Bacillus fusiformis based on the biochemical and morphological characterization as well as 16S rDNA sequencing. KMK 5 could tolerate and degrade azo dyes, Disperse Blue 79 (DB79) and Acid Orange 10 (AO10) under anoxic conditions. Complete mineralization of DB79 and AO10 at the concentration of 1.5g/l was observed within 48h. This degradation potential increased the applicability of this microorganism for the dye removal.

Very late stent thrombosis after implantation of drug eluting stent.

A case of late stent occlusion of a Sirolimus eluting Cypher stent (Cordis, Johnson and Johnson) presenting as acute ST elevation myocardial infarction 22 months after deployment is reported. The possible mechanisms are discussed.

Delayed occurrence of restenosis in drug eluting stents: an evidence of delayed healing.

Drug eluting stents have made a significant impact on restenosis. However, there are concerns regarding delayed "catch-up" of restenosis. In this case report we present two such patients with delayed occurrence of restenosis after drug eluting stent implantation.

Coronary stent implantation without lesion predilatation (direct stenting): our experience with this evolving technique.

BACKGROUND: Until recently, conventional intracoronary stent deployment required predilatation of the lesion with a balloon. However, "direct stenting" of the lesion without predilatation offers certain theoretical and practical advantages. We assessed the safety and feasibility of direct stenting in a select group of patients who were likely to benefit most from these advantages, namely, those with acute coronary syndromes. saphenous vein graft lesions, associated renal or left ventricular dysfunction and those requiring multivessel intervention. METHODS AND RESULTS: After direct stenting, intravascular ultrasound was used to assess the adequacy of stent expansion in 51 patients. One hundred and twenty patients with a total of 125 lesions (83.3% males, average age 54.6+/-12.4 years) were enrolled for direct stenting. Of these, 90% of patients had presented with acute coronary syndromes, 21.6% of patients had associated moderate-to-severe left ventricular systolic dysfunction, 6.7% of patients had associated renal dysfunction and 30.8% of patients required multivessel intervention. Angiographically visible thrombus was present in 35.2% of patients. The mean reference diameter of the lesion was 3.18+/-0.32 mm and mean percentage diameter stenosis was 76.4+/-11.2%. Almost all varieties of stents were used (8.8% bare and 91.2% mounted). Procedural success was achieved in 98.3% of patients (98.4% of lesions). In two cases, the lesion had to be predilated prior to stenting. On angiography, the need for postdilatation of the stent was apparent in 29 (23.6%) lesions. In contrast, on intravascular ultrasound evaluation done in 51 lesions after stent deployment, the need for postdilatation to optimize stent expansion was seen in 43 (84.3%) lesions. There was one instance of acute stent thrombosis and two instances of slow-flow phenomenon. There were no deaths, myocardial infarction or need for urgent bypass surgery. CONCLUSIONS: We conclude that direct stenting is feasible and safe in selected groups of patients. Optimization of stent expansion after direct stenting may often require aggressive postdilatation.

Management of chronic stable angina pectoris from a sceptic's view point.

Ischaemic heart disease is a leading cause of death in the world. It has clinically defined phases as: Asymptomatic, stable angina, progressive angina and unstable angina. It is important to differentiate patients of angina into those with stable and unstable angina--risk stratification and management differ in the two groups. Risk stratification of patients with stable angina using clinical parameters helps in development of clearer indication of referral for exercise testing and cardiac catheterisation. Chronic stable angina patients with history of documented myocardial infarction of Q waves on ECG should have measurement of left ventricular systolic function (ie, ejection fraction) as it is important for choosing the appropriate medical or surgical therapy. Symptomatic patients with suspected or known coronary artery disease should usually undergo exercise testing to assess the risk of future cardiac events. The treatment of stable angina has two purposes: To prevent myocardial infarction and death and therapy directed towards preventing death. Pharmacotherapy consists of: Aspirin, lipid lowering agents, beta-blockers, nitrates, short acting dihydropyridine calcium antagonists, etc. For surgery, there are two well established approaches of revascularisation. One is coronary artery by-pass grafting and the other is percutaneous transluminal coronary angioplasty. Studies comparing different treatment modalities are elaborated in this article. In conclusion, it can be said that patients having severe symptoms affecting quality of life despite optimal medical therapy should be referred for revascularisation surgery.

Multi-vessel coronary stenting--procedural results and late clinical outcomes: a comparison with single-vessel stenting.

The purpose of this study was to assess the 1-year clinical outcome of patients with multi-vessel coronary artery disease (CAD) who underwent coronary stenting, and to compare the results with single-vessel coronary stenting carried out during the same period. We evaluated the in-hospital and 12-month clinical outcomes [death, Q-wave myocardial infarction (MI) and repeat revascularization rates at one year] in 384 consecutive patients treated with coronary stents in 2 (92% of patients) or 3 of the native coronary arteries and compared the outcome to 624 consecutive patients undergoing stenting in a single coronary artery between January 1, 1997 and January 31, 1999. The overall procedural success was obtained in 99% of patients with 2- or 3-vessel stenting and 98% of patients with single-vessel stenting. Procedural complications were similar (2.9% vs 2.6%; p = 0.12). During follow-up, target lesion revascularization was 16% in multi-vessel and 14% in single-vessel stenting (p = 0.38) and repeat revascularization was also similar for both groups (19% vs. 20%; p = 0.73). There was no difference in death (0.8% vs. 1.3%; p = 0.31) and Q-wave MI (0.7% vs. 1.4%; p = 0. 16) in the 2 groups. Overall cardiac event-free survival was similar for both groups (76% vs. 78%; p = 0.54). Multi-vessel stenting in carefully selected patients in our experience had a high procedural success with very low complication rates. The one-year clinical outcomes were acceptable and were similar to the results of single-vessel stenting.

Coronary stent thrombosis: time course and clinical outcome.

The current clinical practice of stent implantation has changed over the last few years. We analysed the incidence and time course of stent thrombosis in patients undergoing successful coronary angioplasty and stenting over the last three years. All the patients were treated with aspirin and ticlopidine. A total of 13 patients experienced stent thrombosis. The mean age was 52+/-12 years; 12 were smokers and 10 had a recent history of myocardial infarction. None of these patients had received abciximab. The median time from stent implantation to stent thrombosis was 10 hours, with all the stent occlusions occurring within 18 hours of stent implantation procedure. All the patients underwent a repeat intervention at a median time of 30 minutes after the clinical suspicion of stent occlusion. On follow-up of 1 to 24 months, three patients developed reocclusion. In the present era of coronary angioplasty and stenting, when interventional procedures are not pre-planned and patients are treated with aspirin and ticlopidine or clopidogrel at the time of stent implantation, the incidence of stent thrombosis is low; it is seen mainly in patients with recent myocardial infarction, majority of them being smokers, and occurs within 18 hours in all the patients.

Photon-echo novelty filter: a unique time-differential sensor of optical wave-front distortion caused by airborne turbulence.

To continue our earlier research on the photon-echo novelty filter, we lengthen the novelty filter's response time by 3 orders of magnitude from nanoseconds to microseconds. On the microsecond time scale of airborne turbulence we demonstrate the potential of the novelty filter as a unique time-differential phase sensor. We observe no considerable degradation of the filter's sensitivity and accuracy to as high as 50 and 200 micros, respectively. This result demonstrates that the filter can be continuously tuned with regard to its response time over a wide range. We further apply the novelty filter to the probing of phase distortions of a laser beam going through a He jet. We also investigate issues regarding the operation of the novelty filter to deal with random and spatially nonuniform phase distortion. The relation of the photon-echo novelty filter to traditional double-exposure holography and the role of the time-differential sensor in adaptive optics are discussed.

Algorithm for the extraction of page-formatted binary digital data.

We present an algorithm for fast and reliable extraction of page-formatted binary digital data. The advantages of the algorithm include a low raw bit-error rate, fast extraction speed, the use of a simple and density-efficient coding scheme, and large tolerance to a change of the signal-to-noise ratio. We used this algorithm to analyze shot-noise-limited binary data that had large interpage and intrapage intensity variations and obtained an improvement in the bit-error rate of 3-4 orders of magnitude compared with that in a single-threshold-detection scheme. Implications of our results for the development of high-speed, high-density holographic memories are discussed.

Observation of photon echo in Er(3+):YAG at 1.527 microm.

We report what is to our knowledge the first experimental observation of two- and three-pulse echoes in Er(3+) :YAG at 1.527microm . The experiment was performed on the transition from the (4)I(15/2) ground state to the lowest Stark level of the (4)I(13/2) excited state. The corresponding homogeneous dephasing time was measured to be approximately 50ns at 1 and 7K. In addition, three-pulse echo decay indicated a lifetime of the spectral grating of ~30micros . Implications of these results for optical data storage and optical signal processing are discussed.

High-efficiency nonvolatile holographic storage with two-step recording in praseodymium-doped lithium niobate by use of continuous-wave lasers.

We have observed efficient two-photon, two-step recording in a praseodymium-doped lithium niobate crystal by use of cw lasers. Single-photon erasure during the readout at near-infrared wavelengths was found to be negligible. Nonvolatile holographic image storage was demonstrated. This progress is an important step in the realization of an economically feasible nonvolatile read-write holographic recording system based on low-cost semiconductor diode lasers.

Optimization of time-domain storage density in the presence of excitation-induced spectral diffusion.

We present a technique to reduce the loss of storage capacity in time-domain optical memory in the presence of excitation-induced spectral diffusion. We applied this technique to a Eu(3+):Y(2) SiO(5)-based memory that utilizes frequency chirp for recording-retrieval and successfully stored 860 bits of data in a 40-MHz data channel. In comparison with the conventional chirp method under identical experimental conditions, the present technique offers an increase of a factor of ~2 in storage capacity with no measurable loss of signal fidelity. The results are interpreted in terms of the phase error accumulated during dephasing-rephasing and spectral diffusion on excited-state relaxation.