Manoj Kumar

Microbial enzymes: industrial progress in 21st century

Biocatalytic potential of microorganisms have been employed for centuries to produce bread, wine, vinegar and other common products without understanding the biochemical basis of their ingredients. Microbial enzymes have gained interest for their widespread uses in industries and medicine owing to their stability, catalytic activity, and ease of production and optimization than plant and animal enzymes. The use of enzymes in various industries (e.g., food, agriculture, chemicals, and pharmaceuticals) is increasing rapidly due to reduced processing time, low energy input, cost effectiveness, nontoxic and eco-friendly characteristics. Microbial enzymes are capable of degrading toxic chemical compounds of industrial and domestic wastes (phenolic compounds, nitriles, amines etc.) either via degradation or conversion. Here in this review, we highlight and discuss current technical and scientific involvement of microorganisms in enzyme production and their present status in worldwide enzyme market.Graphical abstract

Higher efficacy of sequential therapy with interferon-alpha and lamivudine combination compared to lamivudine monotherapy in HBeAg positive chronic hepatitis B patients.

BACKGROUND:Monotherapy with interferon (IFN) or lamivudine is effective in a limited proportion of chronic hepatitis B (CHB) patients. A sequential combination may have better therapeutic effects by sustained viral suppression combined with immunomodulation.AIM:To compare the efficacy of sequential lamivudine and IFN therapy versus lamivudine monotherapy in HBeAg positive CHB patients.PATIENTS AND METHODS:Seventy-five treatment naïve HBeAg positive patients with histologically proven CHB and alanine aminotransferase (ALT) >1.5 × ULN received lamivudine 100 mg per day for 52 wks with IFN 5 MIU per day added for 16 wks after the first 8 wks (group A, n = 38; age 30 ± 12 yr; M:F = 35:3) or lamivudine 100 mg per day for 52 wks (group B, n = 37; age 30 ± 16 yr; M:F = 31:6). Biochemical and virologic responses were assessed at weeks 52 and 76 and analysis was done on intention-to-treat. Serial samples were studied for the emergence of lamivudine-resistant YM552I/VDD mutations by direct sequencing.RESULTS:At week 52, HBeAg loss occurred in 15 (39.5%) in group A and 14 (37.8%) in group B (p = 1.00). HBeAg loss, anti-HBe appearance, and undetectable DNA levels were seen in 26.3% and 13.5% (p = 0.249), respectively. Nine of 10 (90%) patients in group A and 1 of 5 (20%) in group B maintained the response through week 76 (p = 0.017). At week 76, 5 additional patients in group A and 3 in group B further achieved the primary end point and the overall HBeAg loss was observed in 44.7% and 18.9% (p = 0.025) and HBeAg loss, anti-HBe appearance, and undetectable hepatitis B virus (HBV) DNA levels in 36.8% and 10.8% in group A and group B, respectively (p = 0.026). At week 76, undetectable HBV DNA was seen in 39.5% and 16.2% in groups A and B, respectively (p = 0.039). Normal ALT was seen in 47.7% and 40.5% at week 52 (p = 0.489) and ALT was normal in 39.5% and 13.5% at week 76 (p = 0.018) in groups A and B, respectively. YM552I/VDD-resistant mutants emerged in 6 of 38 (15.5%) patients in group A, and 3 of 37 (8.1%) in group B (p = ns). The rate of histological improvement was comparable in the two groups.CONCLUSIONS:Our results demonstrate that sequential therapy is superior to lamivudine monotherapy in achieving sustained seroconversion, ALT normalization, and HBV DNA loss. Compared to 80% with sequential therapy, only 20% Indian patients with CHB did not relapse after stopping lamivudine monotherapy.

Epitaxial growth of high quality ZnO:Al film on silicon with a thin γ-Al2O3 buffer layer

ZnO:Al thin films were grown epitaxially on epi-γ-Al2O3/Si (111) substrates by rf sputtering and pulsed laser deposition. The γ-Al2O3 buffer layer was deposited on Si (111) at a low substrate temperature of 500u200a°C using the metalorganic chemical vapor deposition method. Reflection high energy electron diffraction and x-ray diffraction measurements indicated a near alignment of the ZnO:Al epilayer on γ-Al2O3/Si (111) as compared to those grown directly on Si (111). Atomic force microscopy results of the films ZnO:Al/γ-Al2O3/Si (111) deposited by pulsed laser deposition revealed a smoother surface in comparison with the films deposited by rf sputtering. The M band observed in the photoluminescence spectra of the films deposited by laser ablation suggests that high quality epitaxial ZnO:Al/γ-Al2O3/Si (111) films can be deposited by pulsed laser deposition.

Hepatitis E virus as an etiology of acute exacerbation of previously unrecognized asymptomatic patients with hepatitis B virus-related chronic liver disease

Background and Aim:u2002 Hepatitis E virus (HEV) has recently been implicated in episodes of acute decompensation in patients having underlying chronic liver disease (CLD) of varying etiology. However, HEV as a cause of acute exacerbation of previously asymptomatic and unrecognized hepatitis B virus (HBV)‐infected patients is less well described. The aim of the present study was to investigate the etiology of acute exacerbation of previously asymptomatic and unrecognized HBV‐infected patients and to evaluate the relative role of HEV. We also investigated the effect of superinfection on the clinical spectrum of underlying HBV infection.

Impact of gate material engineering(GME) on analog/RF performance of nanowire Schottky-barrier gate all around (GAA) MOSFET for low power wireless applications

In this paper Gate Material Engineered (GME) Gate-Stack (GS) silicon nanowire Schottky-Barrier (SB) Gate All Around (GAA) MOSFET and Single Material Gate Stack Schottky-Barrier Source/Drain Gate All Around (SM-GS-SB-S/D GAA) structures are proposed for low- power wireless applications. The Analog/RF performance for wireless applications of these devices are demonstrated. The effect of Schottky-Barrier (Metal) S/D is studied for Single Metal (SM)-SB-GAA, (Dual Metal) DM-SB-GAA, SM-GS-SB-GAA and GME-GS-SB-GAA MOSFETs, and it is found that GME-GS-SB-GAA MOSFET with metal drain source shows much improved performance in terms of transconductance (gm), output conductance (gd), Early Voltage (VEA), Maximum Transducer Power Gain, cut-off frequency (fT), and Ion/Ioff ratio. Further, harmonic distortion for wireless applications is also studied using ATLAS-3D device simulator. Due to low parasitic S/D resistance the metal Source/Drain DM-GS-SB-S/D-GAA MOSFET demonstrates remarkable Ion of~31.8µA/µm and saturation transconductance gm of~68.2µS with improved third order derivative of transconductance gm3. High cut-off frequency of Dual Metal-Schottky Barrier-GAA MOSFET: 193GHz.Highest Ion/Ioff ratio of DM-GS-SB-GAA MOSFET: 9.58×104.High transconductance of DM-GS-SB-GAA MOSFET: 68.2µS.Low power VDS=50mV, with suppressed gm3.Lightly doped channel (NA=1×1016cm-3 ), amalgamation of Dual metal Gate.

Is the mitral valve area flow-dependent in mitral stenosis? A Dobutamine stress echocardiographic study

OBJECTIVESnThe purpose of this study was to compare the effect of changes in flow rate on the mitral valve area (MVA) derived from two-dimensional echocardiographic planimetry and Doppler pressure half-time (PHT) methods in patients with mitral stenosis (MS).nnnBACKGROUNDnDobutamine stress echocardiography has been proposed as a means of assessing the severity of MS. However, data regarding the effect of an increase in flow rate on MVA are limited. If MVA is indeed flow-dependent, this has important implications for the assessment of the severity of MS, particularly in the setting of reduced cardiac output (CO).nnnMETHODSnDobutamine echocardiography was performed in 57 patients with isolated MS who were in sinus rhythm. The MVA was determined by planimetry and Doppler PHT methods.nnnRESULTSnCardiac output increased by > or =50% in 27 patients (group I) and by <50% in 30 patients (group II). In group I, the MVA by planimetry increased by only 10.6 +/- 2% and the MVA by PHT increased by 21.9 +/- 4.8%. These changes were similar to those observed in group II (10.7 +/- 3% and 14.8 +/- 4%, respectively; p = NS), despite a much smaller increase in CO. A clinically important change (from the severe to mild category) occurred in only one patient when using the PHT method and in none by planimetry.nnnCONCLUSIONSnChanges in flow rate result in small but clinically insignificant changes in echocardiographic MVA measurement. These methods provide an accurate assessment of MS severity in a majority of patients, independent of changes in flow rate.

Purification and Characterization of Enterocin LR/6, a Bacteriocin from Enterococcus faecium LR/6

Enterocin LR/6, a bacteriocin obtained from the culture filtrate of Enterococcus faecium strain LR/6, has been purified to homogeneity using ammonium sulfate precipitation, cation-exchange chromatography, gel-filtration, and checked on reverse-phase high-performance liquid chromatography. It is active at high temperatures (boiling as well as autoclaving) and over a wide range of pH (2.0–8.0). Also, it is sensitive to a number of proteolytic enzymes but is stable in the presence of surfactants and organic solvents. The protein could be stored at least up to 1xa0year at low temperatures (4xa0°C and −20xa0°C) without any loss of activity. The N-terminal sequence of enterocin LR/6 showed no homology with known enterocins or other bacteriocins present in the database, suggesting it to be a novel enterocin. Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry and tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed its mass to be ∼6.1xa0kDa. It showed a bactericidal mode of action against indicator strain, Micrococcus luteus.

An Analysis of Local Spatial Temperature Patterns in The Delhi Metropolitan Area

The present study focuses on spatial patterns of urban heat island (UHI) development within the rapidly changing urban landscape of the Delhi Metropolitan Region (DMR). To determine the role of local environmental factors in the shaping of microclimatic conditions, automated weather sensors were installed at 13 sites for a one-year period from May 2007 to June 2008. The results indicate significant differences in observed near-surface temperatures among the different stations. The UHI effect was more pronounced in the late afternoon and nocturnal hours. The highest temperatures are observed in the northern and western sections of the study area, which overlap with high-density residential and industrial land uses. Furthermore, these areas also experienced extreme high temperatures of prolonged duration during the daytime, increasing heat-related risks in these areas. At the seasonal level, the greatest differences in temperatures were observed during the summer, likely due to the predominantly clear sky conditions. However, areas of higher temperatures were relatively localized during the cooler months of the year.

Antilisterial Activity of a Broad-Spectrum Bacteriocin, Enterocin LR/6 from Enterococcus faecium LR/6

Enterocin LR/6, a purified bacteriocin, exhibited broad inhibitory spectrum both against related as well as some food-borne pathogens such as Listeria monocytogenes, Yersinia enterocolitica, Aeromonas sp.,Shigella sp., and Bacillus licheniformis. In this investigation, we have focused on L. monocytogenes as the target organism, as it is not only an important pathogen but can also survive over a wide range of environmental conditions such as refrigeration temperature, low pH, and high-salt concentration. This allows the pathogen to overcome many food preservation and safety barriers and poses a potential risk to human health. The enterocin LR/6 showed a bactericidal action against L. monocytogenes and completely inhibited the growth on agar plates, supplemented with 200xa0AU/ml of enterocin LR/6. The effectiveness of enterocin LR/6 in completely killing a population of acid-adapted (pH 5.2, 2xa0h) L. monocytogenes exposed to different temperatures (4–37xa0°C), pH (2.5–8.0), and osmotic (up to 30% NaCl) stress is reported here. This paper focuses on the key issue of killing of the acid-adapted L. monocytogenes cells under adverse environmental conditions.

Process development for the production of bioethanol from waste algal biomass of Gracilaria verrucosa

The algal biomass of different species of Gracilaria were collected from coasts of Orissa and Tamil Nadu, India and characterized biochemically. Among various species, G. verrucosa was found to be better in terms of total carbohydrate content (56.65%) and hence selected for further studies. The agar was extracted from algal biomass and the residual pulp was enzymatically hydrolyzed. The optimization of algal pulp hydrolysis for various parameters revealed a maximum sugar release of 75.8mg/ml with 63% saccharification yield. The fermentation of enzymatic hydrolysate of algal pulp was optimized and 8% (v/v) inoculum size, 12h inoculum age, pH 5.0 were found to be optimum parameters for maximum ethanol concentration (27.2g/L) after 12h. The process of enzymatic hydrolysis and fermentation were successfully scaled up to 2L bioreactor scale.