Effect of systemic herbicides on N2-fixing and phosphate solubilizing microorganisms in relation to availability of nitrogen and phosphorus in paddy soils of West Bengal

A field experiment has been conducted with four systemic herbicides viz., butachlor [N-(butoxymethyl)-2-chloro-2',6'-diethyl-acetanilide], fluchloralin [N-(2-chloroethyl)-(2,6-dinitro-N-propyl-4-trifluoromethyl) aniline], oxadiazon [5-terbutyl-3-(2,4-dichloro-5-isopro poxyphenyl)-1,3,4-oxadiazol-2-one] and oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenyl)-4-(trifluoromethyl) benzene] at their recommended field rates (2.0, 1.5, 0.4 and 0.12kga.i.ha(-1), respectively) to investigate their effects on growth and activities of aerobic non-symbiotic N(2)-fixing bacteria and phosphate solubilizing microorganisms in relation to availability of nitrogen and phosphorus in the rhizosphere soils as well as yield of the rice crop (Oryza sativa L cv. IR-36). Application of herbicides, in general, highly stimulated the population and activities of the target microorganisms, which resulted in a greater amount of atmospheric nitrogen fixation and phosphate solubilization in the rhizosphere soils of the test crop. The greater microbial activities subsequently augmented the mineralization and availability of nitrogen and phosphorus in the soil solution, which in turn increased the yield of the crop. Among the herbicides, oxyfluorfen was most stimulative followed by fluchloralin and oxadiazon in augmenting the microbial activities in soil. Butachlor also accentuated the mineralization and availability of nitrogen due to higher incitement of non-symbiotic N(2)-fixing bacteria in paddy soil. The grain and straw yields of the crop were also significantly increased due to the application of oxyfluorfen (20.2% and 21%) followed by fluchloralin (13.1% and 15.4%) and butachlor (9.1% and 10.2%), respectively.     

Characterization of fluoride-tolerant halophilic Bacillus flexus NM25 (HQ875778) isolated from fluoride-affected soil in Birbhum District, West Bengal, India

A new Gram-positive, nonpigmented, rod-shaped fluoride-tolerant bacterial strain, NM25, was isolated from waterlogged muddy field soil collected from the fluoride endemic area of Rampurhat II block (average fluoride in water, 4.7 mg/l, and in soil, 1.5 mg/kg) in Birbhum District, West Bengal, India. The study was undertaken to characterize the fluoride-tolerant bacterial isolate, to determine its role in bioaccumulation of fluoride, and to analyze the water and soil quality of the bacterial environment. The isolate was positive for catalase, lipase, urease, protease, oxidase, and H₂S production, but negative for indole production, nitrate reduction, and Vogues–Proskauer test. The organisms were sensitive to recommended doses of ofloxacin, kanamycin, rifampicin, levofloxacin, vancomycin, gatifloxacin, gentamicin, doxycycline, streptomycin, and nalidixic acid but resistant to ampicillin. Based on the phenotypic characteristics, 16S rRNA gene sequence, and phylogenetic analysis, the bacterial isolate NM25 was identified as Bacillus flexus. The G+C content of the 16S rDNA was 53.14 mol%. This strain tolerated up to 20 % (w/v) NaCl in nutrient agar medium and was grown at the pH range 4–12. It reduced fluoride concentration up to 67.45 % and tolerated more than 1,500 ppm of fluoride in brain–heart infusion agar medium.     

Development of Anticorrosive Poly(Ether-Urethane) Amide Coatings from Linseed Oil: A Sustainable Resource

Polyetheramide(PEtA) resin was synthesized by the condensation polymerization of N,N-bis(2-hydroxy ethyl) linseed oil fatty amide diol (HELA) with resorcinol. It was further treated with different percentage of toluylene 2-4-diisocyanate (TDI) to obtain the urethane modified polyetheramide resins (UPEtA). The structural elucidation of PEtA and urethane modified polyetheramide(UPEtA) were carried out by FT-IR, ¹H-NMR and ¹³C-NMR spectroscopic techniques. These analyses confirm the formation of PEtA and UPEtA. Physico-chemical and physico-mechanical analysis were performed by standard laboratory methods. The resin composition UPEtA-24 showed best physico-mechanical properties with scratch hardness 2.0 kg, impact resistance 150 lb/in. and good bending ability. The thermal stability and curing behavior of polymers were respectively studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Thermal analysis shows that these coatings can be used safely upto 190 °C. The coatings of UPEtA resins were prepared on mild steel strips. The anticorrosive behavior of UPEtA coatings were investigated in acid, alkali, water and xylene. All the coatings exhibit good chemical resistance performance in acid, alkali, saline and organic solvents, while the resin UPEtA-24 shows the best performance.     

Assessment of genetic variation in lucerne (Medicago sativa L.) using protease inhibitor activities and RAPD markers

The aim of the present study is to identify and characterize lucerne lines resistance to weevil infestation. After three years of field screening for resistance to weevil infestation, 13 lines of lucerne were selected to assess the genotypic variations for lucerne weevil (Hypera postica Gyll.) at biochemical and molecular levels. Total phenols varied from 0.15 to 0.91 mg g (DM) in these genotypes. The highest trypsin (11.11 unit mg(-1) protein) and chymotrypsin (93.0 unit mg(-1) protein) inhibitors activities were recorded in G-1-02 and B-4-03 lines respectively, whereas highest alpha-amylases inhibitor activity (14.2 unit mg(-1) protein) in C-6-01. Zymogram patterns for trypsin inhibitor activity showed quantitative variations among the lines. In total 262 DNA fragments were generated when 45 deca-mer random primers were employed. Genetic variation in terms of genetic distance ranged from 0.65 to 0.85. Sequential Agglomerative Hierarchical and Nested (SAHN) clustering using the Un-weighted Pair Group Method with Arithmetic mean (UPGMA) algorithm yielded two clusters (cluster I and II) which converged at 72% similarity level. Cluster I contained most of the lines having low level of weevil infestation. High bootstrap values (>40) indicated the significance of nodes embodied in these two clusters. However, SDS-PAGE analysis of the leaf proteins of these 13 lines showed no major variations except minor difference in the protein bands of molecular weights between 14 to 20 kD.     

Influence of lignin, pentachlorophenol and heavy metal on antibiotic resistance of pathogenic bacteria isolated from pulp paper mill effluent contaminated river water

Pulp paper mill pollutants are the major source of aquatic contamination having metals, lignin and chlorophenols. Study was conducted to see the effect of these contaminants on antibiotic resistance pattern of isolated bacteria. Pulp paper effluents were evaluated for its physico-chemical properties i.e, BOD 72143 +/- 164.81 to 22.32 +/- 2.48, COD 213136 +/- 583.59 to 60.40 +/- 6.34, total phenol 386 +/- 71.24 to 0.43 +/- 0.0, lignin 26312 +/- 258.59 to 73.67 +/- 31.81and microbial quality i.e. K. pneumonae, S. typhi, S. faecalis, P. aeruginosa, E. coli, Ent. faecalis, A. hydrophila, B. subtilis, S. aureus, Y enterolitica and V vulrificus. Antibiotic sensitivity (10-30 microg), heavy metal resistance (100-1000 microg ml(-1)), lignin (1000-10,000 ppm) and pentachlorophenol (100-1000 ppm) tolerance of bacterial strains were assessed by seven classes of antibiotics. Eleven bacterial isolates were found multidrug resistant towards antibiotics, heavy metal, lignin and PCP. Out of 11 isolates, 90.9% were found resistant against eleven antibiotics which acquired 100% resistant in presence of heavy metal, lignin and chlorophenols. Results also revealed that concentration of lignin (50-350 ppm) and PCP (5-30 ppm) induced maximum growth (273-8050 cfu ml(-1)) of pathogenic bacteria in river water.     

An updated review on advancement in fermentative production strategies for biobutanol using Clostridium spp.

A significant concern of our fuel-dependent era is the unceasing exhaustion of petroleum fuel supplies. In parallel to this, environmental issues such as the greenhouse effect, change in global climate, and increasing global temperature must be addressed on a priority basis. Biobutanol, which has fuel characteristics comparable to gasoline, has attracted global attention as a viable green fuel alternative among the many biofuel alternatives. Renewable biomass could be used for the sustainable production of biobutanol by the acetone-butanol-ethanol (ABE) pathway. Non-extinguishable resources, such as algal and lignocellulosic biomass, and starch are some of the most commonly used feedstock for fermentative production of biobutanol, and each has its particular set of advantages. Clostridium, a gram-positive endospore-forming bacterium that can produce a range of compounds, along with n-butanol is traditionally known for its biobutanol production capabilities. Clostridium fermentation produces biobased n-butanol through ABE fermentation. However, low butanol titer, a lack of suitable feedstock, and product inhibition are the primary difficulties in biobutanol synthesis. Critical issues that are essential for sustainable production of biobutanol include (i) developing high butanol titer producing strains utilizing genetic and metabolic engineering approaches, (ii) renewable biomass that could be used for biobutanol production at a larger scale, and (iii) addressing the limits of traditional batch fermentation by integrated bioprocessing technologies with effective product recovery procedures that have increased the efficiency of biobutanol synthesis. Our paper reviews the current progress in all three aspects of butanol production and presents recent data on current practices in fermentative biobutanol production technology.

     

Photocatalytic remediation of methylene blue and antibacterial activity study using Schiff base-Cu complexes

This work describes the design of novel Cu(II) complexes and their application in the photocatalytic degradation of methylene blue (MB). The same photocatalyst exhibits antibacterial activity against Escherichia coli (gram-negative) and Bacillus circulans (gram-positive). The characterisation of the photocatalysts has been done by several up-to-date physical methods. The rationale behind the photocatalysts’ beneficial intervention is discussed in this study. Statistical analysis of the degradation of MB is done using a one-way ANOVA, and the significance of means is determined by a multiple comparison test using Turkey HSD. Also, the degradation of MB follows pseudo first-order kinetics with high correlation coefficient values (R²?>?0.95), making them useful as simple and low-cost organic dye degradation agents.

     

Tribal institutions and conservation of the bioculturally valuable ‘tasat’ (Arenga obtusifolia) tree in the eastern Himalaya

This study reports on the biocultural dimensions of the tasat (Arenga obtusifolia Griff.) tree and its conservation by various informal institutions of the Adi tribe of Arunachal Pradesh, India. The study included 240 Adi community members (120 men and 120 women) residing in 12 villages of the East Siang and Upper Siang districts of Arunachal Pradesh. The study was conducted using personal interviews and participatory methods. Results indicated that the stem of tasat is used as a traditional food during droughts and in preparing an ethnic beverage. Tasat is being conserved by the Adi tribe in various habitats. Plant populations of tasat were observed relatively higher in Upper Siang than the East Siang district. The study found differences in the status of biocultural knowledge between genders and different age groups. Kebang and reglep are two indigenous institutions of men and women, respectively, and play leading roles in sustaining tasat plants in various habitats. Women of the Upper Siang district still maintain a knowledge network for diffusing biocultural knowledge related to tasat, among others, through a barter system. Changing land use patterns in agriculture affects tasat conservation. The value addition for tasat based products, and rewarding women who conserve tasat, can enhance the sustainability of tasat based on biocultural knowledge and institutions.     

Nanodiagnostics for plant pathogens

Rapid detection technologies with high sensitivity and selectivity for plant pathogens are essential to prevent disease spread and minimize losses to assure optimal productivity and food security. Traditional laboratory techniques such as microscopy and culture are time-consuming, labour intensive and require complex sample handling. Immunological and molecular techniques have advanced but have some issues related to rapidity, signal strength and instrumentation. The integration of immunological and molecular diagnostics with nanotechnology systems offers an option where all detection steps can be accommodated on a portable miniaturized device for rapid and accurate detection of plant pathogens. The sensitive nature of functionalized nanoparticles can be used to design phytopathogen detection devices with smart sensing capabilities for field use. This review summarizes the current status and future prospects of nanotechnology for detection and diagnosis of plant pathogens.