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Manipulation of aqueous droplets in microchannels has great significance in various emerging applications such as biological and chemical assays. Magnetic-field based droplet manipulation that offers unique advantages is consequently gaining attention. However, the physics of magnetic field-driven cross-stream migration and the coalescence of aqueous droplets with an aqueous stream are not well understood. Here, we unravel the mechanism of cross-stream migration and the coalescence of aqueous droplets flowing in an oil based ferrofluid with a coflowing aqueous stream in the presence of a magnetic field. Our study reveals that the migration phenomenon is governed by the advection (τa) and magnetophoretic (τm) time scales. Experimental data show that the dimensionless equilibrium cross-stream migration distance δ* and the length L δ * required to attain equilibrium cross-stream migration depend on the Strouhal number, St = (τa/τm), as δ* = 1.1 St0.33 and L δ * = 5.3 S t − 0.50 , respectively. We find that the droplet-stream coalescence phenomenon is underpinned by the ratio of the sum of magnetophoretic (τm) and film-drainage time scales (τfd) and the advection time scale (τa), expressed in terms of the Strouhal number (St) and the film-drainage Reynolds number (Refd) as ξ = (τm + τfd)/τa = (St−1 + Refd). Irrespective of the flow rates of the coflowing streams, droplet size, and magnetic field, our study shows that droplet-stream coalescence is achieved for ξ ≤ 50 and ferrofluid stream width ratio w* < 0.7. We utilize the phenomenon and demonstrated the extraction of microparticles and HeLa cells from aqueous droplets to an aqueous stream. [ABSTRACT FROM AUTHOR]

We report the dynamical behaviour of aqueous ferrofluid droplets (FFDs) of different sizes and concentrations at the interface of coflowing immiscible oils in a microchannel in the presence of the magnetic field. We show that the migration and sorting phenomena are governed by the interplay between magnetic force F m , non-inertial lift force F l , and interfacial tension force F i . Depending on the force ratios, namely, the lift force ratio [ K L = F l / F i ] and magnetic force ratio [ K M = F m / F i ], three different regimes are identified. The results also reveal that the FFD trajectory and migration length ( L m i g * ) depend on the net force ratio [ F R , n e t = F m + F l / F i ] and magnet location x m * . Finally, size-based sorting of FFD is demonstrated, which shows a remarkable improvement in terms of the size range and resolution compared to when the magnetic field is not present. [ABSTRACT FROM AUTHOR]

The present research work was undertaken to investigate the effect of xylanase, produced by Penicillium citrinum, on rheological behavior of whole wheat bread dough at large and small deformation respectively. Dough attributes including textural properties (penetration) and structure related characteristics (oscillatory tests) were evaluated. Change in visco-elastic properties of xylanase containing dough was evaluated by oscillatory and creep measurements. The flow experiments were conducted under steady-state condition with shear rate ranging from 0.01 to 100 s. Frequency sweep experiments were performed between 0.01 and 10 Hz. It revealed that in both control and xylanase containing dough formulation, the elastic modulus was higher than viscous modulus in the entire range of frequency. Our results represent the adequacy of fitting of dynamic moduli in Power law model and week gel model. Peleg model as well as six element Kelvin model described well the creep behaviour of control and xylanase-containing dough. Uniaxial extensibility was assessed by Kieffer dough and gluten extensibility rig. Lyophilized powder of untreated and xylanase treated doughs were tested under scanning electron microscope. FTIR spectra of lyophilized powder of untreated and xylanase treated dough were recorded in the range of 600-4000 cm. [ABSTRACT FROM AUTHOR]

The role of urban form in influencing travel behaviour has gained particular interest to scholars and policy makers to achieve a broader goal of sustainability despite varied scholastic opinion on the effectiveness of this relationship. While transportation forms the nexus of any urban environment, it also accounts for about thirty-six per cent of the total energy consumption in the UK [Department of Energy and Climate Change, UK, ]. Thus, an emphasis to reduce greenhouse emissions in this sector remains a key policy objective to achieve sustainability. Also there is an overemphasis of research in this area on quantitative association between key variables as opposed to qualitative exploration in order to understand complex human behaviour. The study reported in this paper has been designed to address this gap. Using a grounded theory analysis, this paper reports findings from 6 focus group discussions and 17 in-depth interviews. Fifty-three participants were recruited from three case study areas across Northern Ireland to represent the urban continuum. Seven overarching categories have been identified explaining the interrelationships between urban form and travel behaviour in the Northern Ireland context. However, at a macro-scale, land-use policies have played a dominant role in shaping the travel patterns and this has translated in the form of car dependency and residential immobility over the years in Northern Ireland. Although current policy now adopts a more integrated approach to curb urban sprawl and achieve modal split, soft policy measures have proved useful in increasing the effectiveness of these policy interventions. [ABSTRACT FROM AUTHOR]

Xylanase constitutes an important class of hydrolases, and is used in numerous industrial applications. The aim of the present work was to study the production of xylanase from Penicillium citrinum MTCC 9620 in a 5 L stirred tank bioreactor. Effect of various process parameters; pH, temperature, aeration, agitation rates, substrate concentration, and, dissolved oxygen (DO) concentration on xylanase production were studied. Combination of all the optimized parameters resulted in 2.5 times higher enzyme activity as compared to the shake flask fermentation after 96 h. Effect of varying agitation and aeration on the volumetric mass transfer coefficient (KLa) was determined. It revealed that KLa is influenced by both aeration and agitation. Growth kinetics of P. citrinum MTCC 9620 in bioreactor was studied using Monod, Moser, Contois and Edward equation. Based on R², SE and pattern of residuals, the microbial growth kinetics of P. citrinum MTCC 9620 was effectively represented by Moser equation. [ABSTRACT FROM AUTHOR]

A new chemical and the first chemoenzymatic synthesis of β-adrenergic receptor blocking agent bunitrolol is reported in racemic (RS) and enantioenriched forms (R and S). The intermediates (R)- and (S)-1-chloro-3-(2-cyanophenoxy)propan-2-ol intermediates were synthesized from the corresponding racemic alcohol through enzymatic kinetic resolution. The commercial available lipases PS-C and CCL exhibited complementary enantioselectivity during transesterification of the racemic alcohol with vinyl acetate affording the (R)-alcohol along with (S)-acetate and the (S)-alcohol along with (R)-acetate, respectively, and represent an example of enzymatic switch for reversal of enantioselectivity. The effects of various reaction parameters, such as temperature, time, substrate and enzyme concentration, and reaction medium, on the activity and enantioselectivity were optimized. The (R)- and (S)-alcohols were converted into (S)-and and (R)-bunitrolol, respectively, by treatment with tert-butylamine. The (R)- and (S)-acetates, obtained enzymatically were deacetylated to the corresponding alcohol by chemical hydrolysis and further converted into (S)-and and (R)- bunitrolol by chemical means. This is the first chemoenzymatic synthesis of both of the enantiomers of the drug. (RS)-, (R)-, and (S)- Bunitrolol were also synthesized following the 'all chemical' routes from (RS)-, (R)-, and (S)-epichlorohydrin via the corresponding (RS)-, (S)-, and (R)-2-cyanoglycidyl ether and the (RS)-, (R)-, and (S)-1-chloro-3-(2-cyanophenoxy)propan-2-ol intermediates with improved overall yields and better enantiomeric excesses compared to the reported processes. [ABSTRACT FROM AUTHOR]

The intracellular cobalt-type nitrile hydratase was purified from the bacterium Rhodococcus erythropolis. The pure enzyme consisted of two subunits of 29 and 30 kDa. The molecular weight of the native enzyme was estimated to be 65 kDa. At 25 °C the enzyme had a half-life of 25 h. The Michaelis-Menten constants K and v for the enzyme were 0.624 mM and 5.12 μmol/min/mg, respectively, using 3-cyanopyridine as the substrate. The enzyme-containing freely-suspended bacterial cells and the cells immobilized within alginate beads were evaluated for converting the various nitriles to amides. In a packed bed reactor, alginate beads (2 % alginate; 3 mm bead diameter) containing 200 mg/mL of cells, achieved a conversion of >90 % for benzonitrile and 4-cyanopyridine in 38 h (25 °C, pH 7.0) at a feed substrate concentration of 100 mM. The beads could be reused for up to six reaction cycles. [ABSTRACT FROM AUTHOR]

Background Changes that occur to red blood cells ( RBCs) during routine blood bank storage include decreased deformability, increased haemolysis and oxidative damage. Oxidative injury to the RBC membrane and haemoglobin can affect changes in shape and deformability. Ascorbic acid ( AA) is an antioxidant that maintains haemoglobin in a reduced state and minimises RBC oxidative injury. We hypothesised that AA would improve membrane fragility and decrease haemolysis during storage. Methods Whole blood derived, AS-5 preserved, pre-storage leucoreduced RBC units were exposed to either AA or saline control solutions. Several rheological and biochemical parameters were measured serially during storage, including RBC membrane mechanical fragility, percent haemolysis and methaemoglobin levels. Results AA exposure significantly reduced mechanical fragility and haemolysis over the entire storage period. The highest two concentrations of AA affected the greatest reductions in mechanical fragility and percent haemolysis. Addition of AA to the RBCs did not significantly alter their biochemical parameters compared to control RBCs incubated with saline. Conclusion AA reduced RBC membrane fragility and decreased haemolysis during storage without adversely affecting other RBC biochemical parameters. The clinical significance of these findings needs to be determined. [ABSTRACT FROM AUTHOR]

The present study deals with the characterization of industrial effluents released from various industries and distribution of heavy metals in effluent discharge channel and its impact on the river Damodar. The effluent of tamlanala, a natural storm water channel, is extensively used for irrigation for growing vegetables in and around the study area. The heavy metals in water of the study area are in the order of Fe > Mn > Pb >Cd and sediments follow similar trends too. The enrichment of heavy metals in the sediments are in the order of Cd (39.904) > Pb (33.156) > Mn (0.164) > Fe (0.013). The geoaccumulation index values reveal effluent channel is subjected to moderate to high pollution with respect to Cd (4.733) and Pb (4.466). The analyzed data for enrichment factors and the pollution load index (1.305) show that effluent channels have suffered from significant heavy metal contamination following industrialization and urbanization. Compared to baseline values, the surface sediment layers show high enrichment across the channel and at its discharge point. The factor analysis reveals three factors—industrial sources, surface runoff inputs, and background lithogenic factors which clarify the observed variance of the environmental variables. Metal pollution assessment of sediments suggests that pollution from the heavy metals observed is high in the tamlanala which in turn affects the downstream of the river system. [ABSTRACT FROM AUTHOR]

Immobilized cells of a recombinant Escherichia coli expressing nitrilase from Pseudomonas putida were used to catalyze the hydrolysis of mandelonitrile (2-hydroxy-2-phenylacetonitrile) to ( R)-(−)-mandelic acid. The cells had been immobilized by entrapment in an alginate matrix. Conditions for the hydrolysis reaction were optimized in shake flasks and in a packed bed reactor. In shake flasks the best conditions for the reaction were a temperature of 40 °C, pH 8, biocatalyst bead diameter of 4.3 mm, sodium alginate concentration in the gel matrix of 2 % (w/v, g/100 mL), a cell dry mass concentration in the bead matrix of 20 mg/mL, an initial substrate concentration of 50 mM and a reaction time of 60 min. Under these conditions, the conversion of mandelonitrile was nearly 95 %. In the packed bed reactor, a feed flow rate of 20 mL/h at a substrate concentration of 200 mM proved to be the best at 40 °C, pH 8, using 4.3 mm beads (2 % w/v sodium alginate in the gel matrix, 20 mg dry cell concentration per mL of gel matrix). This feed flow rate corresponded to a residence time of 0.975 h in the packed bed. [ABSTRACT FROM AUTHOR]

Solid-state fermentation of sugarcane bagasse by Pénicillium citrinum MTCC 2553 was optimized to maximize the yield of xylanase. Preliminary experiments carried out with various lignocellulosic materials revealed sugarcane bagasse to be the most suitable substrate for producing xylanase. Response surface methodology was used in the optimization. Xylanase activity was maximized in a 5-day batch fermentation carried out under the following conditions: a substrate-to-moisture ratio of 1:5 by mass, an initial pH of 7.0 and an incubation temperature of 30 °C. Under the optimal conditions, the final activity of xylanase was 1645 U g-1 of dry substrate. Xylanase was recovered from an extract of the fermented solids by ammonium sulfate precipitation. The crude enzyme was further purified by dialysis. The activity of the enzyme was enhanced in the presence of Na+, Mg2+, Mn2+, Fe3+, Zn2+, Cu2+, Co2+ and Tween 80. The enzyme was inhibited by Hg2+, Ca2+ and the chelating agent ethylene diamine tetra acetic acid (EDTA). [ABSTRACT FROM AUTHOR]

Xanthine oxidoreductase (XOR) is a ubiquitous complex cytosolic molybdoflavoprotein which controls the rate limiting step of purine catabolism by converting xanthine to uric acid. It is known that optimum concentrations of uric acid (UA) and reactive oxygen species (ROS) are necessary for normal functioning of the body. The ability of XOR to perform detoxification reactions, and to synthesize UA and reactive oxygen species (ROS) makes it a versatile intra- and extra-cellular protective 'housekeeping enzyme'. It is also an important component of the innate immune system. The enzyme is a target of drugs against gout and hyperuricemia and the protein is of major interest as it is associated with ischemia reperfusion (I/R) injury, vascular disorders in diabetes, cardiovascular disorders, adipogenesis, metabolic syndrome, cancer, and many other disease conditions. Xanthine oxidoreductase in conjugation with antibodies has been shown to have an anti-tumor effect due to its ability to produce ROS, which in turn reduces the growth of cancer tissues. Apart from this, XOR in association with nitric oxide synthase also participates in myocardial excitation-contraction coupling. Although XOR was discovered over 100 years ago, its physiological and pathophysiological roles are still not clearly elucidated. In this review, various physiological and pathophysiological functional aspects of XOR and its association with various forms of cancer are discussed in detail. [ABSTRACT FROM AUTHOR]

bacterial strain, Bacillus cereus M (MTCC 5521), isolated and identified in our laboratory produces a green pigment when grown in nutrient broth at stationary condition. Optimum fermentation parameters for maximum pigment production are pH 7.0, temperature 30°C, time of incubation 72 h and inoculum volume 1% from 20 h grown cell suspension. Magnesium ion enhances pigment production whereas calcium and zinc ions inhibit the process. The pigment is better extracted from the fermented broth with chloroform in comparison with diethyl ether, ethyl acetate, and butanol. The extracted crude pigment consists of three fractions as revealed from thin layer chromatogram on silica gel GF254 using ethyl acetate and hexane (1:1) solvent system. The major fraction C shows antibacterial activity against different gram positive bacteria. The proposed structure of C is 9-methyl-1,4,5,8-tetra-azaphenanthrene obtained by elemental analysis, GC-MS, and NMR spectra studies. [ABSTRACT FROM AUTHOR]

In this paper, we have obtained an approximation result in the Generalized Finite Element Method (GFEM) that reflects the global approximation property of the Partition of Unity (PU) as well as the approximability of the local approximation spaces. We have considered a GFEM, where the underlying PU functions reproduce polynomials of degree l. With the space of polynomials of degree k serving as the local approximation spaces of the GFEM, we have shown, in particular, that the energy norm of the GFEM approximation error of a smooth function is O( h). This result cannot be obtained from the classical approximation result of GFEM, which does not reflect the global approximation property of the PU. [ABSTRACT FROM AUTHOR]

Aims: To evaluate the effect of different physicochemical parameters such as agitation, aeration and pH on the growth and nitrile hydratase production by Rhodococcus erythropolis MTCC 1526 in a stirred tank reactor. Methods and Results: Rhodococcus erythropolis MTCC 1526 was grown in 7-l reactor at different agitation, aeration and controlled pH. The optimum conditions for batch cultivation in the reactor were an agitation rate of 200 rev min−1, aeration 0·5 v/v/m at controlled pH 8. In this condition, the increase in nitrile hydratase activity was almost threefold compared to that in the shake flask. Conclusion: Agitation and aeration rate affected the dissolved-oxygen concentration in the reactor which in turn affected the growth and enzyme production. Significance and Impact of the Study: Cultivation of R. erythropolis MTCC 1526 in the reactor was found to have significant effect on the growth and nitrile hydratase production when compared to the shake flask. [ABSTRACT FROM AUTHOR]

Nitrilases have attracted tremendous attention for the preparation of optically pure carboxylic acids. This article aims to address the production and utilization of a highly enantioselective nitrilase from Pseudomonas putida MTCC 5110 for the hydrolysis of racemic mandelonitrile to ( R)-mandelic acid. The nitrilase gene from P. putida was cloned in pET 21b(+) and over-expressed as histidine-tagged protein in Escherichia coli. The histidine-tagged enzyme was purified from crude cell extracts of IPTG-induced cells of E. coli BL21 (DE3). Inducer replacement studies led to the identification of lactose as a suitable and cheap alternative to the costly IPTG. Effects of medium components, various physico-chemical, and process parameters (pH, temperature, aeration, and agitation) for the production of nitrilase by engineered E. coli were optimized and scaled up to a laboratory scale bioreactor (6.6 l). Finally, the recombinant E. coli whole-cells were utilized for the production of ( R)-(−)-mandelic acid. [ABSTRACT FROM AUTHOR]

The insolubility of nitrile substrates in aqueous reaction mixture decreases the enzymatic reaction rate. We studied the interaction of fourteen water miscible organic solvents with immobilized nitrile hydrolyzing biocatalyst. Correlation of nitrilase function with physico–chemical properties of the solvents has allowed us to predict the enzyme behavior in such non-conventional media. Addition of organic solvent up to a critical concentration leads to an enhancement in reaction rate, however, any further increase beyond the critical concentration in the latter leads to the decrease in catalytic efficiency of the enzyme, probably due to protein denaturation. The solvent dielectric constant ( ε) showed a linear correlation with the critical concentration of the solvent used and the extent of nitrile hydrolysis. Unlike alcohols, the reaction rate in case of aprotic solvents could be linearly correlated to solvent log P. Further, kinetic analysis confirmed that the affinity of the enzyme for its substrate ( K m) was highly dependent upon the aprotic solvent used. Finally, the prospect of solvent engineering also permitted the control of enzyme enantioselectivity by regulating enantiomer traffic at the active site. [ABSTRACT FROM AUTHOR]

To determine the distribution of species of Candida and the risk factors associated with candidemia in Indian population for which we conducted a retrospective study for 5 years in a tertiary care centre of North India. Blood samples from 7,297 patients aged from 3 days to 85 years, suspected with candidemia, were collected and tested for Candida. The susceptibility patterns toward fluconazole for the year 2005 isolates were tested by micro-dilution assay as described in the CLSI (M27A-2 method). Most of the episodes have been caused by species other than C. albicans. Non-albicans candidemia was 79%–80% in both female and male populations. The most frequent species isolated from 275 patients in 5 years (January 2001–December 2005) was C. tropicalis (35.3%), followed by C. albicans (21.5%), C. parapsilosis (20%), C. glabrata (17.5%), C. krusei (3.3%), C. haemulonii (1.5%), and C. guilliermondii (1%). C. parapsilosis was the predominant in the fifth year of the study (2004–2005). Dose-dependant susceptibility to fluconazole was observed in 5% (n = 3) of the strains. Antifungal resistance was found in 11.7% (n = 7), which includes only C. glabrata. These results were comparable to those derived from other regions of India. C. tropicalis has been reported as the predominant species involved in the cases of candidemia. But in 2005 it has moved toward C. parapsilosis. No true antifungal resistance is reported. Further epidemiological surveillance is needed. [ABSTRACT FROM AUTHOR]

Background: Combination antibiotic regimens are effective in the treatment of actinomycetoma but many treatment schedules require supervised parenteral therapy for prolonged periods. We describe a schedule that includes parenteral medication in an initial, short phase followed by a longer phase of oral medication.Methods: Sixteen patients with clinically diagnosed mycetoma, who did not show any evidence of a fungal etiology, were treated presumptively for actinomycetoma. Evidence of actinomycotic infection was found on microscopy of granules / discharge and / or histopathological examination in eight (50%) patients. The treatment consisted of an intensive phase (Step 1) with gentamicin, 80 mg twice daily, intravenously and cotrimoxazole, 320/1600 mg twice daily orally for four weeks. This was followed by a maintenance phase with cotrimoxazole and doxycycline, 100 mg twice daily till all sinuses healed completely. The treatment was continued for 5-6 months.Results: Treatment response was assessed monthly. At the end of the intensive phase, there was a significant improvement in all 16 patients. Nine patients who continued the maintenance phase of the regimen had complete healing of sinuses with marked reductions in swelling and induration in 2.4 +/- 1.7 months. Maintenance treatment was continued for a mean of 9.1 +/- 4.3 months in these patients. Six patients have remained free of disease activity during a follow-up period of 11.1 +/- 4.2 months after treatment was stopped. Two patients developed leucopenia and thrombocytopenia necessitating withdrawal of cotrimoxazole.Conclusion: This regimen was effective in treating actinomycetoma. The short duration of the phase requiring parenteral therapy makes it convenient to administer. [ABSTRACT FROM AUTHOR]

( R)-mandelic acid was produced from racemic mandelonitrile using free and immobilized cells of Pseudomonas putida MTCC 5110 harbouring a stereoselective nitrilase. In addition to the optimization of culture conditions and medium components, an inducer feeding approach is suggested to achieve enhanced enzyme production and therefore higher degree of conversion of mandelonitrile. The relationship between cell growth periodicity and enzyme accumulation was also studied, and the addition of the inducer was delayed by 6 h to achieve maximum nitrilase activity. The nitrilase expression was also authenticated by the sodium dodecyl phosphate-polyacrylamide gel electrophoresis analysis. P. putida MTCC 5110 cells were further immobilized in calcium alginate, and the immobilized biocatalyst preparation was used for the enantioselective hydrolysis of mandelonitrile. The immobilized system was characterized based on the Thiele modulus (ϕ). Efficient biocatalyst recycling was achieved as a result of immobilization with immobilized cells exhibiting 88% conversion even after 20 batch recycles. Finally, a fed batch reaction was set up on a preparative scale to produce 1.95 g of ( R)-(-)-mandelic acid with an enantiomeric excess of 98.8%. [ABSTRACT FROM AUTHOR]

The highly enantioselective arylacetonitrilase of Pseudomonas putida was purified to homogeneity using a combination of (NH4)2SO4 fractionation and different chromatographic techniques. The enzyme has a molecular weight of 412 kDa and consisted of approximately nine to ten identical subunits (43 kDa). The purified enzyme exhibited a pH optimum of 7.0 and temperature optimum of 40°C. The nitrilase was highly susceptible to thiol-specific reagents and metal ions and also required a reducing environment for its activity. These reflected the presence of a catalytically essential thiol group for enzyme activity which is in accordance with the proposed mechanism for nitrilase-catalyzed reaction. The enzyme was highly specific for arylacetonitriles with phenylacetonitrile and its derivatives being the most preferred substrates. Higher specificity constant ( k cat/ K m) values for phenylacetonitrile compared to mandelonitrile also revealed the same. Faster reaction rate achieved with this nitrilase for mandelonitrile hydrolysis was possibly due to the low activation energy required by the protein. Incorporation of low concentration (<5%) of organic solvent increased the enzyme activity by increasing the availability of the substrate. Higher stability of the enzyme at slightly alkaline pH and ambient temperature provides an excellent opportunity to establish a dynamic kinetic resolution process for the production of ( R)-(−)-mandelic acid from readily available mandelonitrile. [ABSTRACT FROM AUTHOR]

Nitrilases constitute an important class of hydrolases, however, cheap and ready availability of enzyme sources limit their practical synthetic applications. The present investigation was directed to compare the applicability of various physical cell disintegration methods namely, solid shear, liquid shear and sonication, for the release of an enantioselective nitrilase from Alcaligenes faecalis MTCC 126. Different parameters associated with each method were optimized in order to ensure maximal release of active nitrilase. The methods were also compared under optimal conditions for their efficiency of nitrilase release and extent of cell disruption, and enzyme release were visualized under a differential interference contrast microscope (DIC) and SDS-PAGE, respectively. Maximum release of the enzyme protein from the cells was observed in case of liquid shear method employing high-pressure homogenization, however, the specific activity of nitrilase was highest in cell-free extract (CFE) generated by sonication. Both the solid shear and liquid shear proved to be equally effective for maximum release of intracellular enzymes, however, from the specific activity point of view, sonication was found to be a better one compared to other two methodologies. The generated cell-free extract can be further employed for the production of enantiopure chiral carboxylic acids, which are important chiral building blocks. [ABSTRACT FROM AUTHOR]

Cyanobacteria (blue-green algae) are photosynthetic prokaryotes used as food by humans. They have also been recognized as an excellent source of vitamins and proteins and as such are found in health food stores throughout the world. They are also reported to be a source of fine chemicals, renewable fuel and bioactive compounds. This potential is being realized as data from research in the areas of the physiology and chemistry of these organisms are gathered and the knowledge of cyanobacterial genetics and genetic engineering increased. Their role as antiviral, anti-tumour, antibacterial, anti-HIV and a food additive have been well established. The production of cyanobacteria in artificial and natural environments has been fully exploited. In this review the use of cyanobacteria and microalgae, production processes and biosynthesis of pigments, colorants and certain bioactive compounds are discussed in detail. The genetic manipulation of cyanobacteria and microalgae to improve their quality are also described at length. [ABSTRACT FROM AUTHOR]

A yeast strain, Candida tropicalis PBR-2, isolated from soil, is capable of carrying out the enantioselective reduction of N,N-dimethyl-3-keto-3-(2-thienyl)-1-propanamine to (S)-N,N-dimethyl-3-hydroxy-3-(2-thienyl)-1-propanamine, a key intermediate in the synthesis of the chiral drug (S)-Duloxetine. The organism produced the enantiopure (S)-alcohol with a good yield (>80%) and almost absolute enantioselectivity, with an enantiomeric excess (ee) >99%. Parameters of the bioreduction reaction were optimized and the optimal temperature and pH for the reduction were found to be 30°C and 7.0, respectively. The optimized substrate and the resting cell concentration were 1 g/l and 250 g/l, respectively. The preparative-scale reaction using resting cells of C. tropicalis yielded the (S)-alcohol at 84–88% conversion and ee >99%. [ABSTRACT FROM AUTHOR]

Biological removal of dyes from effluents of textile and dyestuff manufacturing industry offers some distinct advantages over the commonly used chemicals and physicochemical methods. These include possible mineralization of the dyes to harmless inorganic compounds like carbon dioxide and water, and formation of a lesser quantity of relatively harmless sludge. Removal of dyes from these wastewaters has been reviewed with respect to biological decolorization as well as complete biodegradation of the dye molecules. Emerging techniques with reference to biological treatment of these wastewaters have been discussed under aerobic, anaerobic, and combined anaerobic–aerobic systems. Advantages and limitations of different biological methods have been highlighted, and future studies to establish these techniques for their applications on industrial scale have been suggested. [ABSTRACT FROM AUTHOR]

Aspergillus niger van Teighem, isolated in our laboratory from samples of rotten wood logs, produced extracellular phytase having a high specific activity of 22,592 units (mg protein)−1 . The enzyme was purified to near homogeneity using ion-exchange and gel-filtration chromatography. The molecular properties of the purified enzyme suggested the native phytase to be oligomeric, with a molecular weight of 353 kDa, the monomer being 66 kDa. The purified enzyme exhibited maximum activity at pH 2.5 and 52–55°C. The enzyme retained 97% activity after a 24-h incubation at 55°C in the presence of 10 mM glycine, while 87% activity was retained when no thermoprotectant was added. Phytase activity was not affected by most metal ions, inhibitors and organic solvents. Non-ionic and cationic detergents (0.1–5%) stabilise the enzyme, while the anionic detergent (SDS), even at a 0.1% level, severely inhibited enzyme activity. The chaotropic agents guanidinium hydrochloride, urea, and potassium iodide (0.5–8 M), significantly affected phytase activity. The maximum hydrolysis rate ( Vmax) and apparent Michaelis-Menten constant ( Km) were 1,074 IU/mL and 606 μM, respectively, with a catalytic turnover number of 3×105 s−1 and catalytic efficiency of 3.69×108 M−1 s−1. [ABSTRACT FROM AUTHOR]

Transthoracic lung aspiration was performed in 30 episodes of pneumonia in 27 children with malignancy on chemotherapy to assess etiology of pulmonary infections. Total of 22 organisms were isolated in 16/30 (53.3%) episodes. No acid fast bacilli or Pneumocystis carinii were seen. Organisms grown by blood culture correlated with that of lung puncture in 5 episodes, while throat culture and nasopharyngeal organisms correlated with that of lung puncture on one occasion each. Organisms isolated in 8/18 episodes (44.4%) of antemorten transthoracic aspiration included: Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Streptococcus faecalis and Diphtheroids. In 3/18 episodes, lung puncture results altered treatment and thus resulted in survival of the patients. Only one minor complication occurred in this study--pneumothorax that resolved spontaneously. Thus, transthoracic lung puncture is an useful and safe procedure in immunocompromised patients with pneumonia who do not respond to initial broad spectrum antibiotics. [ABSTRACT FROM AUTHOR]

Nitrile-converting enzymes are becoming commonplace in the synthesis of pharmaceuticals and commodity chemicals. These versatile biocatalysts have potential applications in different fields including synthetic biocatalysis and bioremediation. This review attempts to describe in detail the three major classes of nitrile-converting enzymes, namely nitrilases, nitrile hydratases and amidases. Various aspects of these enzymes including their occurrence, mechanism of action, characteristics and applicability in different sectors have been elaborately elucidated. Cloning of genes related to nitrile-converting enzymes is also discussed. [ABSTRACT FROM AUTHOR]

Infections are the major cause of morbidity and mortality in acute leukemia patients. Case records of 91 consecutive patients (AML-48, ALL-40, RAEB-t/AML-3) treated between January 1997 and July 1999 were studied to determine the type, frequency and severity of infections. Patients' median age was 36 y (range 6–66) and male to female ratio was 2.5:1. A total of 240 febrile episodes were recorded; of them, 162 were associated with neutropenia (absolute neutrophil count, ANC<500/mm3) and 78 were without neutropenia. Among the neutropenic episodes, an infectious etiology could be documented in 52%; the remainder (485) were defined as isolated febrile episodes. Chest was the most common site of infection (35.7%) followed by skin, soft tissue (13%), GIT (7%) and genitourinary tract (6%) infections in order of decreasing frequency. Microbiologically, gram positive organisms ( staphylococcus aureus, coagulase negative staphylococcus, streptococcus, enterococcus) were the most common isolates (52.8%) followed by gram negative organisms ( E. coli, klebsiella, pseudomonas) in 42.8% of isolates. Two patients had pulmonary tuberculosis and three patients had fungal infections ( candida—2, aspergillus—1). Among non-neutropenic patients, infection could be documented in 36%; the remaining 64% were isolated febrile episodes. Gram negative infections were documented in 50%, gram positive in 305 and fungal infections ( candia—4, aspergillus—1, mucormycosis—1) in 20% of them. A combination of third generation cephalosporin and an aminoglycoside were used in 79% of episodes initially; a combination of a newer, penicillin and aminoglycoside (4.6%), double betalactums (4.1%), oral, antibiotics (9.8%) and others were used in the remaining episodes. Fever resolved in 38%, of episodes using the above combinations; in the remainder second line antibiotics (mainly vancomycin) and antifungals (amphotericin-B) were added empirically or depending on culture and sensitivity. In 52.5% of episodes fever resolved after addition of second line antibiotics and antifungals. 11 of 91 patients died of infectious complications in this study. There is a need for improvised diagnostic tests to detect infections early, as well as for new therapies to overcome antimicrobial resistance. [ABSTRACT FROM AUTHOR]

An extracellular β-galactosidase which catalyzed the production of galacto-oligosaccharide from lactose was harvested from the late stationary-phase of Bacillus sp MTCC 3088. The enzyme was purified 36.2-fold by ZnCl2 precipitation, ion exchange, hydrophobic interaction and gel filtration chromatography with an overall recovery of 12.7%. The molecular mass of the purified enzyme was estimated to be about 484 kDa by gel filtration on a Sephadex G-200 packed column and the molecular masses of the subunits were estimated to be 115, 86.5, 72.5, 45.7 and 41.2 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point of the native enzyme, determined by polyacrylamide gel electrofocusing, was 6.2. The optimum pH and temperature were 8 and 60°C, respectively. The Michaelis–Menten constants determined with respect to o-NO2-phenyl-β-D-galactopyranoside and lactose were 6.34 and 6.18 mM, respectively. The enzyme activity was strongly inhibited (68%) by galactose, the end product of lactose hydrolysis reaction. The β-galactosidase was specific for β-D anomeric linkages. Enzyme activity was significantly inhibited by metal ions (Hg2+, Cu2+ and Ag+) in the 1–2.5 mM range. Mg2+ was a good activator. Catalytic activity was not affected by the chelating agent EDTA. Journal of Industrial Microbiology & Biotechnology (2000) 24, 58–63. [ABSTRACT FROM AUTHOR]

A new strain of Bacillus sp. was isolated from a hot water spring in India. This strain generated a high activity of extracellular β-galactosidase at 37 °C in shake flasks. The β-galactosidase activity was found to increase continuously but the production rate was slower than with some other organisms reported in the literature. There were noteworthy differences in the time-domain profiles of bacterial concentration and β-galactosidase activity when the starting concentration of substrate (glucose) was tripled from 10 g/L. These differences may be explained in terms of the relative rates of enzyme synthesis and its diffusion across the cell wall. The enzyme produced by this organism is more stable than other β-galactosidases; its half-life is 408 h at 50 °C and 94 h at 55 °C, while the reported enzymes showed perceptible loss of activity within 2 h. [ABSTRACT FROM AUTHOR]

In this paper, we derive error estimates in L-norm, 1≦ p≦∞, for the ℒ-Finite Element approximation to solutions of boundary value problems, where the coefficients are functions of bounded variation. The ℒ-Finite Element Method was introduced in [3] and was shown to be effective for problems with non-smooth coefficient. [ABSTRACT FROM AUTHOR]

A class of generalized finite element methods for the approximate solution of fourth order two point boundary value problem with nonsmooth coefficient is presented. The methods are based on the use of problem dependent L-splines incorporating the nonsmoothness of the coefficient. Stability is proved and optimal error estimates in the H norm are derived for the solution and postprocessed solution, under the assumption that the coefficient is of bounded variation. The relation of these methods to mixed methods is discussed. [ABSTRACT FROM AUTHOR]

Bacteria, yeast and filamentous fungi were isolated from various sites within a paper mill. Bacillus alvei and Aerobacter aerogenes were the most prevalent contaminating bacteria. Maximum slime was produced by A. aerogenes (4.2 mg ml-1) at pH 6.5 and by B. alvei (7.2 mg ml-1) at pH 7.5 in white water. The optimum temperature was 40°C for maximum slime production by both organisms. In the presence of levanase, a 25% reduction in dosages of a biocide (Bioplus®) was observed. Killing of A. aerogenes, which was achieved in 8 h with 20 ppm Bioplus®, could be obtained in 6 h with the combined use of levanase and a lower concentration of Bioplus® (15 ppm). With B. alvei almost the same inhibitory effect (4.22-log decrease) was obtained at 20 ppm Bioplus®, and in combination with a lower concentration of Bioplus® (15 ppm) and enzyme. The paper properties did not show any adverse effect after treatment with levanase and Bioplus®. [ABSTRACT FROM AUTHOR]

Decolorization of several dyes (Red HE-8B, Malachite Green, Navy Blue HE-2R, Magenta, Crystal Violet) and an industrial effluent with growing cells of Phanerochœte chrysosporium in shake and static culture was demonstrated. All the dyes and the industrial effluent were decolorized to some extent with varying percentages of decolorization (20–100%). The rate of decolorization was very rapid with Red HE-8B, an industrial dye. Decolorization rates for all the dyes in static condition were found to be less than the shake culture and also dependent on biomass concentration. [ABSTRACT FROM AUTHOR]

Rhodotorula sp. produced a high yield of levanase (12.5 nkat/mL) in shake flasks in basal medium containing 1% maltose as the sole carbon source. Among the different carbon sources used, maltose was found to be the best for levanase production. The optimum temperature and pH for levanase production were 30°C and 6, respectively. In a batch reactor the enzyme productivity was higher (500 nkat L h) than in shaken flasks (347 nkat L h). [ABSTRACT FROM AUTHOR]

A strain of starch-assimilating yeast, Saccharomycopsis capsularis, isolated from Indian cereal-based fermented foods, produced significant levels of extracellular α-amylase and glucoamylase. The enzymes reached their peak activities during the stationary phase at the end of the 5th and 4th day of cultivation, respectively. The amylase yields were maximized by a proper choice of carbon and nitrogen sources, starting pH of the culture medium and growth temperature. High activities of the enzymes were obtained through inexpensive agricultural commodities, such as wheat bran and corn meal as carbon sources, and defatted soybean meal and peanut meal as nitrogen sources. A temperature of 28-32°C and an initial pH of 4.5-5.0 were optimum. The crude amylase mixture could liquefy and saccharify a 1% starch solution completely in 24 h at 50°C. [ABSTRACT FROM AUTHOR]

Curvularia lunata could neither grow nor produce rifamycin oxidase in synthetic media without peptone and yeast extract. Mycelia grown on complex media were tested for the ability to produce rifamycin oxidase in synthetic media. The optimum concentrations of peptone and yeast extract were in the range of 7.5-10 g/L. Five percent inoculum size was found to be optimum for good growth and enzyme production. Addition of metal ions to the cultivation medium increased the enzyme activity. [ABSTRACT FROM AUTHOR]