Synthesis of guar gum maleate under dry conditions: Reaction kinetics and characterization.

In the present study, a novel environment friendly dry method for preparation of guar gum maleate (GGM) with varying degrees of substitution (DS; 0.02-1.04) was optimized. GGM with a maximum DS of 1.04 was successfully synthesized using guar gum (GG) and maleic anhydride (MA) in proportion of 1: 1 at 80 °C with 4 h of reaction time. The activation energy for the reaction was determined to be 36.91 ± 3.61 kJ mol-1 with pre-exponential factor of 1392 min-1. Esterification of GG was confirmed by FT-IR and 13C NMR. Analysis using size exclusion chromatography (SEC) indicated a decrease in weight average molecular weight (Mw) of the polymer with an increase in polydispersity index (PDI) due to esterification. In comparison with GG, GGM displayed increased hydrophobicity and reduced thermal stability, as analysed by differential scanning calorimetry (DSC). Rheological studies of GGM revealed that initial apparent viscosity decreased with increasing DS. For the first time, the study offered valuable insights on GGM synthesis under dry solvent-less reaction conditions enabling simpler and scalable synthesis process.

Effect of Pretilachlor on Soil Enzyme Activities in Tropical Rice Soil.

Pretilachlor treatments, namely, recommended dose at 600 g a.i. ha-1 (RD), double the recommended dose at 1200 g a.i. ha-1 (2RD), ten times of the recommended dose at 6000 g a.i. ha-1 (10RD) along with control, were used to study the effects of pretilachlor on soil enzymes in tropical rice soil. Pretilachlor, at recommended dose completely dissipated 30 days after herbicide application. Twenty days after herbicide application, the dehydrogenase activity was inhibited up to 27 %, 28 % and 40 % of initial values of RD, 2RD and 10RD treatments, respectively. Increase in fluorescein diacetate hydrolase activity was observed during the first 25 days post herbicide application up to 29 %, 36 % and 10 % of initial values of RD, 2RD and 10RD treatments, respectively. ß-Glucosidase activity in the experiment did not provide a specific trend. In general, urease and acid phosphatase activities were not influenced by pretilachlor application. There were significant differences in alkaline phosphatase activities among the treatments until 25 days after herbicide application. Hence, pretilachlor may cause short term transitory changes in soil enzyme parameters. However, it has negative impact on soil enzymes at very high dose.

Structural and thermal characterization of PHAs produced by Lysinibacillus sp. through submerged fermentation process.

In this investigation an attempt has been made to characterize and identify Lysinibacillus sp. 3HHX by 16S-rDNA sequencing. The bacterium exhibited occurrence of PHAs granules on an average 11±1 per cell of 1.0µm length and breadth 0.72µm, revealed from TEM studies. Under optimized condition, 4.006gm/L of PHAs was extracted using hypochlorite digestion and multi-solvent extraction process. PhaC gene of ∼540bp and higher PHA synthase activity was detected at 48h of cultivation. The extracted PHAs was structurally characterized by GC-MS and 1H NMR reported to be P(3HB-co-3HDD-co-3HTD) and amorphous in nature with 112°C melting point, -11.0°C glass transition point and 114.76°C decomposition temperature detected by DSC & TGA respectively. The C/O of biopolymer disc was 1:65 as revealed from C1s and O1s spectra of XPS, that was completely biodegradable within 30 days. This biopolymer was observed to be non-cytotoxic to NIH 3T3 mouse fibroblast cells. The report is of its kind in establishing the abilities of Lysinibacillus sp. 3HHX for non-growth associated PHA co-polymer production. Moreover the biocompatible and biodegradable nature of the biopolymer conferred to its substantial biomedical applications.

Non-target effects of pretilachlor on microbial properties in tropical rice soil.

The use of herbicides has been questioned in recent past for their non-target effects. Therefore, we planned to study the effect of pretilachlor on growth and activities of microbes in tropical rice soil under controlled condition at National Rice Research Institute, Cuttack, India. Three pretilachlor treatments, namely, recommended dose at 600 g a.i. ha(-1) (RD), double the recommended dose at 1200 g a.i. ha(-1) (2RD), and ten times of the recommended dose at 6000 g a.i. ha(-1) (10RD) along with control, were imposed. The initial residue (after 2 h of spray) deposits in soil were 0.174, 0.968, and 3.35 µg g(-1) for recommended, double the recommended, and ten times of the recommended doses, respectively. No residue in soil was detected in RD treatment on day 45. The half life values were 16.90, 17.76, and 36.47 days for RD, 2RD, and 10RD treatments, respectively. Application of pretilachlor at 10RD, in general, had significantly reduced the number of bacteria, actinomycetes, fungi, nitrogen fixers, and microbial biomass carbon. Pretilachlor at RD did not record any significant changes in microbial properties compared to control. The results of the present study thus indicated that pretilachlor at RD can be safely used for controlling grassy weeds in rice fields.

Synthesis of a flexible poly(chloroprene)/methyl red film dosimeter using an environment-benign shear compounding method.

The paper reports synthesis of a new film dosimeter based on a solvent-free route. Methyl red (MR) dye was introduced into poly(chloroprene) (PC) in various concentrations. The films were intensely red with λmax ~515nm. The absorbance decreased linearly with absorbed radiation dose up to 30kGy without a significant change in λmax. Color coordinates of the films were also analyzed. Optical micrographs of the films showed no signs of inhomogeneous distribution of MR in the PC matrix, which was attributed to the polarity of PC. Radiation sensitivity, dose response linearity, effects of irradiation temperature and humidity, as well as the rate of fading, were also investigated.

Reclamation with cyanobacteria: toxic effect of mercury contaminated waste soil on biochemical variables.

During an attempt to decrease the toxicity of industrial waste (soil) from a chloralkali factory by blue-green algae, the effect of the waste soil mixed in varying proportions with garden soil, on biochemical variables was studied. The nucleic acid, protein and free amino acid content of the algae decreased significantly with increasing time and waste soil concentration. The algae accumulated a substantial amount of mercury from the medium depending on the duration of algal growth and waste soil concentration. An increase in RNA/DNA and a decrease in the ratio of protein/RNA and protein/free amino acids was observed.

Characterization of T cell ligands for uromodulin: a possible role in costimulation.

In this study, we demonstrate that uromodulin (UMN) is a costimulator of T cells and characterize the T cell ligand which might mediate its costimulatory effect. UMN is an 85-kDa human urinary glycoprotein which is better known for its ability to suppress antigen-induced proliferation of peripheral blood mononuclear cells. It also has a mitogenic effect on peripheral blood cells, which has not been investigated. In this study, costimulation of T cells by UMN is observed only in the absence of B cells and antigen-specific antiserum. Using ligand binding assays we also demonstrate a specific receptor for UMN on peripheral blood T cells and T cell lines (Kd of 10(-8)). We describe two uromodulin binding proteins of approximate M(r) 35 and 55 kDa, isolated from detergent extract of T cells, either of which may represent a receptor for UMN or an associated signal transduction molecule involved in the stimulatory effect of UMN on T cells. Finally, we demonstrate a similar protein in a renal cell line, which may clarify the renal role of UMN.

In vitro cell aggregation and cell adhesion molecules in Crohn's disease.

BACKGROUND: Lack of a suitable model has hindered efforts to understand inflammation and granuloma formation in Crohn's disease. METHODS: Granulomalike aggregates of circulating mononuclear cells are produced in vitro by cultures of cells with polyacrylamide beads. To identify features of in vitro aggregates, which are similar to tissue granulomas of Crohn's disease, the gross morphology and immunohistological appearance of the aggregates produced with peripheral blood mononuclear cells from patients with Crohn's disease were analyzed, and the size of in vitro aggregates was correlated with clinical activity of the disease. Blocking antibodies were used to evaluate the role of cell-adhesion molecules in the formation of in vitro aggregates. RESULTS: The size of in vitro aggregates correlates very significantly with clinical activity (P < 0.001). In active Crohn's disease, in vitro aggregates show immunohistological features of hypersensitivity type granulomas. Blocking antibodies against leukocyte function associated antigen LFA-2 (CD2), LFA-3 (CD58), and Mac-1 (CD11b/CD18) inhibit in vitro aggregate formation. CONCLUSION: In vitro aggregates model in vivo granulomas in size and organization. Cell adhesion molecules like CD2, CD58, and CD11b/CD18 may be involved in granuloma-formation of Crohn's disease.

The distribution of lymphoid and macrophage like cell subsets of sarcoid and Kveim granulomata: possible mechanism of negative PPD reaction in sarcoidosis.

Immunohistological observations of lymphoid and non-lymphoid cell subsets in biopsies of sarcoid skin granulomas have been compared with positive Kveim tests and the sites of PPD injection in sarcoid patients. Monoclonal antibodies have been used in indirect immunofluorescence often in combination with histochemical methods for the detailed characterization of the cells involved. The antibodies used included two new reagents, RFD-1 and RFD-2, which react with interdigitating cells and acid phosphatase positive macrophages, respectively. Sarcoid granulomas had a distinctive pattern of organization though there was a heterogeneity of macrophage like and T lymphoid cells. In the centre, predominantly HLA-DR+, acid phosphatase positive macrophages (RFD-2+) were seen and the lymphoid cells were almost exclusively T4+. At the periphery of the granulomas the HLA-DR+ dendritic cells were ACP negative and RFD-1+. Here T8+ cells were admixed with the T4+ population. The Kveim granuloma had fewer RFD-2+, macrophages and therefore the RFD-1+ cells were more evenly distributed, but the other cells showed a similar distribution to the established lesions. The PPD injection sites contained fewer T cells than the normal control infiltrates in PPD positive healthy individuals. The T4+/T8+ ratios were about 3:2. The most likely explanation for the PPD anergy in sarcoidosis is the sluggish traffic of T4+ cells which could be due to the sequestration of T4+ cells in sites of ongoing inflammation.