Lokendra Singh

Effect of various carbon and nitrogen sources on cellulose synthesis by Acetobacter xylinum.

The effect of various carbon and nitrogen sources on cellulose membrane production by Acetobacter xylinum was evaluated. Among the carbon sources, sucrose, glucose and mannitol were found to be suitable for optimum levels of cellulose production. The strain was able to utilize a wide range of protein and nitrogen sources such as peptone, soybean meal, glycine, casein hydrolysate, and glutamic acid for cellulose synthesis. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of pellicle proteins (PP) revealed electrophoretic bands of molecular masses in the range of 116–20 kDa. Furthermore, the strain can be useful for the removal of various nitrogenous and carbon substrates present in waste waters.

Groundwater arsenic contamination in Brahmaputra river basin: a water quality assessment in Golaghat (Assam), India

Distribution of arsenic (As) and its compound and related toxicology are serious concerns nowadays. Millions of individuals worldwide are suffering from arsenic toxic effect due to drinking of As-contaminated groundwater. The Bengal delta plain, which is formed by the Ganga–Padma–Meghna–Brahmaputra river basin, covering several districts of West Bengal, India, and Bangladesh is considered as the worst As-affected alluvial basin. The present study was carried out to examine As contamination in the state of Assam, an adjoining region of the West Bengal and Bangladesh borders. Two hundred twenty-two groundwater samples were collected from shallow and deep tubewells of six blocks of Golaghat district (Assam). Along with total As, examination of concentration levels of other key parameters, viz., Fe, Mn, Ca, Na, K, and Mg with pH, total hardness, and SO

Comparative Proteomic Analysis of Extracellular Proteins of Clostridium perfringens Type A and Type C Strains

_{4}^{2-}

A study on the phytoaccumulation of waste elements in wetland plants of a Ramsar site in India

, was also carried out. In respect to the permissible limit formulated by the World Health Organization (WHO; As 0.01xa0ppm, Fe 1.0xa0ppm, and Mn 0.3xa0ppm for potable water), the present study showed that out of the 222 groundwater samples, 67%, 76.4%, and 28.5% were found contaminated with higher metal contents (for total As, Fe, and Mn, respectively). The most badly affected area was the Gamariguri block, where 100% of the samples had As and Fe concentrations above the WHO drinking water guideline values. In this block, the highest As and Fe concentrations were recorded 0.128 and 5.9xa0ppm, respectively. Tubewell water of depth 180 ± 10xa0ft found to be more contaminated by As and Fe with 78% and 83% of the samples were tainted with higher concentration of such toxic metals, respectively. A strong significant correlation was observed between As and Fe (0.697 at p < 0.01), suggesting a possible reductive dissolution of As–Fe-bearing minerals for the mobilization of As in the groundwater of the region.

Construction of a single-chain variable-fragment antibody against the superantigen Staphylococcal enterotoxin B.

ABSTRACT Clostridium perfringens is a medically important clostridial pathogen and an etiological agent causing several diseases in humans and animals. C. perfringens and its toxins have been listed as potential biological and toxin warfare (BTW) agents; thus, efforts to develop strategies for detection and protection are warranted. Forty-eight extracellular proteins of C. perfringens type A and type C strains have been identified here using a 2-dimensional gel electrophoresis-mass spectrometry (2-DE-MS) technique. The SagA protein, the DnaK-type molecular chaperone hsp70, endo-beta-N-acetylglucosaminidase, and hypothetical protein CPF_0656 were among the most abundant proteins secreted by C. perfringens ATCC 13124. The antigenic component of the exoproteome of this strain has also been identified. Most of the extracellular proteins were predicted to be involved in carbohydrate transport and metabolism (16%) or cell envelope biogenesis or to be outer surface protein constituents (13%). More than 50% of the proteins were predictably secreted by either classical or nonclassical pathways. LipoP and TMHMM indicated that nine proteins were extracytoplasmic but cell associated. Immunization with recombinant ornithine carbamoyltransferase (cOTC) clearly resulted in protection against a direct challenge with C. perfringens organisms. A significant rise in IgG titers in response to recombinant cOTC was observed in mice, and IgG2a titers predominated over IgG1 titers (IgG2a/IgG1 ratio, 2). The proliferation of spleen lymphocytes in cOTC-immunized animals suggested a cellular immune response. There were significant increases in the levels of gamma interferon (IFN-γ) and interleukin 2 (IL-2), suggesting a Th1 type immune response.

Diversity and antibiotic susceptibility pattern of cultivable anaerobic bacteria from soil and sewage samples of India

Some wetland plant species are adapted to growing in the areas of higher metal concentrations. Use of such vegetation in remediation of soil and water contaminated with heavy metals is a promising cost-effective alternative to the more established treatment methods. Throughout the year, composite industrial effluents bringing various kinds of heavy metals contaminate our study site, the East Calcutta Wetlands, a Ramsar site at the eastern fringe of Kolkata city (formerly Calcutta), India. In the present study, possible measures for remediation of contaminated soil and water (with elements namely, Ca, Cr, Cu, Pb, Zn, Mn, and Fe) of the ecosystem had been investigated. Ten common regional wetland plant species were selected to study their efficiency and diversity in metal uptake and accumulation. Results showed that Bermuda grass (Cynodon dactylon) had the highest total Cr concentration (6,601 ± 33xa0mgxa0kgu2009−u20091 dw). The extent of accumulation of various elements in ten common wetland plants of the study sites was: Pb (4.4–57xa0mgxa0kgu2009−u20091 dw), Cu (6.2–39xa0mgxa0kgu2009−u20091 dw), Zn (59–364xa0mgxa0kgu2009−u20091 dw), Mn (87–376xa0mgxa0kgu2009−u20091 dw), Fe (188–8,625xa0mgxa0kgu2009−u20091 dw), Ca (969–3,756xa0mgxa0kgu2009−u20091 dw), and Cr (27–660xa0mgxa0kgu2009−u20091 dw) indicating an uptake gradient of elements by plants as Ca>Fe>Mn>Cr>Zn>Cu>Pb. The present study indicates the importance of identification and efficiency of metal uptake and accumulation capabilities by plants in relation to their applications in remediation of a contaminated East Calcutta Wetland ecosystem.

Defluoridation of water using nano-magnesium oxide

ABSTRACT Staphylococcal food poisoning (SFP) is one of the most prevalent causes of food-borne illness throughout the world. SFP is caused by 21 different types of staphylococcal enterotoxins produced by Staphylococcus aureus. Among these, staphylococcal enterotoxin B (SEB) is the most potent toxin and is a listed biological warfare (BW) agent. Therefore, development of immunological reagents for detection of SEB is of the utmost importance. High-affinity and specific monoclonal antibodies are being used for detection of SEB, but hybridoma clones tend to lose their antibody-secreting ability over time. This problem can be overcome by the use of recombinant antibodies produced in a bacterial system. In the present investigation, genes from a hybridoma clone encoding monoclonal antibody against SEB were immortalized using antibody phage display technology. A murine phage display library containing single-chain variable-fragment (ScFv) antibody genes was constructed in a pCANTAB 5E phagemid vector. Phage particles displaying ScFv were rescued by reinfection of helper phage followed by four rounds of biopanning for selection of SEB binding ScFv antibody fragments by using phage enzyme-linked immunosorbent assay (ELISA). Soluble SEB-ScFv antibodies were characterized from one of the clones showing high affinity for SEB. The anti-SEB ScFv antibody was highly specific, and its affinity constant was 3.16 nM as determined by surface plasmon resonance (SPR). These results demonstrate that the recombinant antibody constructed by immortalizing the antibody genes from a hybridoma clone is useful for immunodetection of SEB.

Arsenic removal from water using calcined Mg–Al layered double hydroxide

Soil and sewage act as a reservoir of animal pathogens and their dissemination to animals profoundly affects the safety of our food supply. Moreover, acquisition and further spread of antibiotic resistance determinants among pathogenic bacterial populations is the most relevant problem for the treatment of infectious diseases. Bacterial strains from soil and sewage are a potential reservoir for antimicrobial resistance genes. Accurate species determination for anaerobes from environmental samples has become increasingly important with the re-emergence of anaerobic bacteremia and prevalence of multiple-drug-resistant microorganisms. Soil samples were collected from various locations of planar India and the diversity of anaerobic bacteria was determined by 16S rRNA gene sequencing. Viable counts of anaerobic bacteria on anaerobic agar and SPS agar ranged from 1.0 × 10(2)cfu/g to 8.8 × 10(7)cfu/g and nil to 3.9 × 10(6)cfu/g, respectively. Among clostrdia, Clostridium bifermentans (35.9%) was the most dominant species followed by Clostridium perfringens (25.8%). Sequencing and phylogenetic analysis of C. perfringens beta2 toxin gene (cpb2) fragment indicated specific phylogenetic affiliation with cluster Ia for 5 out of 6 strains. Antibiotic susceptibility for 30 antibiotics was tested for 74 isolates, revealing resistance for as high as 16-25 antibiotics for 35% of the strains tested. Understanding the diversity of the anaerobic bacteria from soil and sewage with respect to animal health and spread of zoonotic pathogen infections is crucial for improvements in animal and human health.

Removal of iron and arsenic (III) from drinking water using iron oxide-coated sand and limestone

Nano-sized magnesium oxide (nano-MgO) was investigated for adsorption of fluoride from water. The pure and fluoride adsorbed nano-MgO were characterised by Brunauer–Emmett–Teller, high resolution transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray analyses. The surface area of the adsorbent was found to be 92.46u2009m2/g. Maximum (90%) fluoride removal was obtained with 0.6u2009g/L dosage of nano-MgO. Fluoride adsorption by nano-MgO was found to be less sensitive to pH variations. Fluoride sorption was mainly influenced by the presence of OH− ion. The presence of other ions studied did not affect the fluoride adsorption capacity of nano-MgO significantly. It has been observed that Freundlich model was better fitted as compared to Langmuir model which indicated the multilayer adsorption of the adsorbent following a pseudo-second order kinetics. Regeneration study showed that 1u2009M HCl was the best eluent with 95% desorption capacity towards fluoride removal followed by NaOH (2u2009M) with 25% regeneration of the adsorbent.

Malaria risk areas of Udalguri district of Assam, India: a GIS-based study

Arsenic (As) in drinking water and its related toxicology are serious concerns nowadays. Development of better techniques related to removal of As from drinking water is an urgent need. Layered double hydroxide (LDH) or hydrotalcite-like compound with the general formula [M1−x2+ Mx3+ (OH)2]x+ Ax−·nH2O can be considered as a good adsorbent for the removal of toxic As from water. Due to large surface area and high anion exchange capacity of LDH, the compound may be a good adsorbent for the removal of As from contaminated water. In this study, the removal of As in aqueous solution by adsorption method based on the calcination–rehydration reaction was investigated in batch experiment at (30xa0±xa01)°C. Results showed the removal of 99.99% As from a solution of 0.1xa0ppm of As; the adsorbent required at saturation was 0.10xa0g/20xa0ml As solution with 90xa0min of exposure at (30xa0±xa01)°C. Factors like pH, adsorbent dose and shaking time influenced the rate of As removal. Experiment showed that the adsorption process follows the Freundlich-type adsorption isotherm. The explanation of adsorption phenomenon is supported by X-ray diffraction pattern.