Showing papers by "Ruma Pal published in 2011"

Response of cyanobacteria to arsenic toxicity

Abstract: Arsenic content of cyanobacterial biomass, soil and water samples from arsenic-contaminated area of eastern India were estimated. It was found that arsenic content in cyanobacterial biomass (276.9 μg g−1) was more than soil (19.01 μg g−1) or water sample (244.13 μg L−1). Shallow tube well water showed more arsenic (244.13 μg L−1) than deep tube well water (146.13 μg L−1). Arsenic resistant genera recorded from the contaminated area were Oscillatoria princeps, Oscillatoria limosa, Anabaena sp. and Phormidium laminosum. Among these, P. laminosum was isolated and exposed to different concentration of Arsenic in vitro (0.1–100 ppm) to study the toxicity level of arsenic. Modulation in stress enzymes and stress-related compounds were studied in relation to lipid peroxidase, catalase, super oxide dismutase (SOD), ascorbate peroxidase (APX), reduced glutathione and carotenoids in arsenic exposed biomass to understand the resistance mechanism of the genus both in laboratory condition as well as in natural condition. Arsenic content of cyanobacterial biomass from contaminated area was more (276.9 μg g−1) than laboratory exposed sample (37.17 μg g−1), indicating bioconcentration of arsenic in long-term-exposed natural biomass. Overall, more activity of catalase was recorded in cyanobacterial biomass of natural condition whereas SOD and APX were at higher level in laboratory culture.

Biochemical composition and lipid characterization of marine green alga Ulva rigida- a nutritional approach

Abstract: Biochemical composition of the green alga Ulva rigida (Ulvophyceae) was investigated by determination of moisture, protein, carbohydrate, total lipid, phenol and chlorophyll content.The moisture content of the alga was 76% whereas total protein was 6.64%, and carbohydrate content was 22%. The total lipid and phenol content were 12% and 23% whereas chlorophyll a, b and total chlorophyll were determined as 13%. 7.5% and 21% respectively. Carotenoid was present in considerable quantities (4.5%). The total free amino acid was found to be 8.9%. Fatty acid composition of total lipid was determined by gas chromatography. The major fatty acids in total lipid were 14:0, 16:0, 18:0, 18:1, 18:2 and 18:3. It was found that major of the biochemical parameters of this alga were higher except the protein content.

Green Synthesis of Gold Nanoparticles Using Cyanobacteria and their Characterization

Abstract: Two cyanobacteria Lyngbya majuscula and Spirulina subsalsa were used as bioreagent for the green synthesis of gold nanoparticles. Within 72 h of incubation at 15 mg L-1 Au3+ solution, the cyanobacterial biomass turned purple indicating intracellular reduction of Au3+ to Au0 and subsequent formation of gold nanoparticles. Gold nanoparticles were extracted from the gold-loaded biomass using 7.5 mM sodium citrate solution and characterization was done by UVvisible spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR). While Spirulina showed synthesis of spherical nanoparticles of 5 nm -30 nm diameter along with very few nanorods, Lyngbya showed presence of spherical and hexagonal nanoparticles of 2 nm -25 nm diameters. XRD study confirmed the reduction of Au3+ to Au0. FTIR analysis indicated the presence of protein shells around the gold nanoparticles.

Synthesis and Characterization of Nanosilver-A blue green approach

Abstract: In our thorough investigation of suitability of cyanobacterial strains, commonly known as blue green algae, for cheap ecofriendly nanometal formation, Leptolyngbya valderianum was found to be an effective bioreagent for nanosilver production. The nanosilver synthesis at intracellular level was indicated by the brown biomass of Leptolyngbya after 72 hrs of dark exposure in 9 mM AgNO3 solution. Intracellular silver particles were extracted from the silver loaded biomass and nanosilver production was determined by UV-vis spectroscopy showing absorption peak at ~411 nm. Extracted nanoparticles were further characterized by dynamic light scattering (DLS), zeta potential and X-ray diffraction (XRD) studies. Transmission electron microscopy (TEM) revealed the spherical shape of AgNPs with 2 to 20 nm in diameter. The XRD indicated the 2θ values at 38.20, 44.50, 65.60 and 78.60 which confirmed again the reduction of Ag (I) to Ag (0). Antibiotic property of the AgNP was tested by Agar well diffusion method. Introduction Silver nanoparticles commonly used for nanomedicine production , are reported to be nontoxic to human but most effective against bacteria, viruses, and other eukaryotic microorganisms at very low concentration (Jeong et al. 2005). They are also effective against tumors with anti-proliferative activity (Sriram et al. 2010). The antimicrobial property allows them to be suitably employed in numerous products such as textiles, food storage containers, home appliances and especially in medical devices (Marambio-Jones et al. 2010). Use of AgNP is in medicine industry as tropical ointments to prevent infection against burn and open wounds is quite effective (Ip et al. 2006). Silver nanoparticles (AgNPs) play important role as pesticide filter also (Pradeep and Anshup 2009). Silver nanoparticles are synthesized by different physical and chemical methods like sol-gel technique, solvo-thermal synthesis, chemical reduction, laser ablation, inert gas condensation etc (Huy et al. 2013). The time consuming physical methods are often difficult to achieve and in chemical methods different toxic reagents are used as capping agent like, cetyl trimethyl ammonium bromide (CTAB) leading to undesirable functional aberrations in target cells. Both physical and chemical procedures are very expensive also. Therefore biosynthesis of AgNPs are becoming popular day by day using microorganisms like bacteria (Klaus et al. 1999, Sweeney et al. 2004, Nair and Pradeep 2002); fungi (Ahmad et al. 2003, Ingle et al. 2009, Mukherjee et al. 2001, Gade et al. 2008, Sanghi et al. 2009) and algae (Govindaraju et al. 2009, Mohseniazar et al. 2011). Only sporadic reports are available regarding filamentous cyanobacteria based AgNP production like, Plectonema boryanum(Lengke et al. 2007), Oscillatoria willei (Ali et al. 2011) and Spirulina platensis (Govindraju et al. 2008). In search for a very suitable bio-reagent for AgNP production, we recorded Leptolyngbya valderianum as more effective strain, as it is widespread in distribution than the studied taxa. They flourish from freshwater to marine region, moreover very cheap production of biomass is possible within very short time reducing the production cost of the nano-metal. Size determination was done in the present investigation employing TEM study and complete characterizations of AgNP were made by XRD, DLS, and Zeta potential studies. Rate of AgNP production per gm biomass was determined and pure nanometal was extracted from the biomass. Antibiotic property was determined by agar well diffusion methods. All these studies would analyze the structure and stability of AgNP in pure form and can be used for further exploitation. Materials and methods The experimental strain, L. valderianum was collected from eastern part of India (Suderbans, West Bengal) and pure strain was obtained from Phycology Laboratory, CU. A small portion of healthy growing biomass (10 mg FW) was exposed to 100 ml of 9 mM Ag (I) solution (pH 3.86), (AgNO3, MW 169.86, Merck, India) and was kept in dark condition at room temperature. After 72 h yellowish brown biomass was removed from the silver nitrate solution and washed with double distilled water. To extract the particles, algal biomass was sonicated for 30 min at 60% amplitude with 7.5 mM sodium citrate solution by a Hielscher UP100H ultrasonic processor (Teltow, Germany) and was centrifuged at 3000 rpm for 5 min in a C-24 BL Remi cooling centrifuge (Maharashtra, India). The supernatant was collected for further analysis. A UV-vis spectrum of the extract was recorded in the wavelength range of 200nm-1100nm with a Thermo Evolution 300 UV-visible spectrophotometer (Waltham, USA). DLS measurement was done with 1 mL of suspension using Nano ZS (Malvern) to study the hydrodynamic size of the particles distributed in citrate solution. Zeta potential of the suspension was determined using the same instrument to determine the stability of the nanoparticles. Silver loaded brown colored biomass was air-dried, made it into powder using mortar and pestle and used for powder XRD analysis. The XRD spectra were recorded from 5° to 100° 2θ angles with a Panalytical PW 3040/60, DY 2501 X-ray diffractometer (Netherland) using Cu Kα radiation operated at 40 kV and 30 mA to confirm the presence of Ag (0). A drop of nanoparticle extract was dried on a carbon coated copper grid and the morphology and size analysis of biosynthesized AgNPs was carried out by JEOL JEM 2100 HR-TEM. The extracted golden brown suspension was lyophilized and nano silver production rate was determined in relation to biomass weight (mg/gm biomass). Antibacterial activity of the synthesized silver nanoparticles was determined using the agar well diffusion method against gram negative bacteria Pseudomonas aeruginosa (MTCC 424). The bacterial strain was obtained from Microbial type culture collection and gene bank (MTCC, Chandigarh, India). The inoculums suspensions were spread uniformly in different nutrient agar plates. Cavities were made in each plate using a well-cutter and it was filled with silver nanoparticle solution (100 ml) with different concentions, 1 mg/ml, 0.5 mg/ml, and 0.1 mg/ml and then incubated at 37 °C. Sodium citrate was used as negative control because AGNPs were suspended in citrate solution. The diameter of clear zone was measured.

Variations in seasonal phytoplankton assemblages as a response to environmental changes in the surface waters of a hypo saline coastal station along the Bhagirathi-Hooghly estuary.

Abstract: Due to the close proximity of the Bay of Bengal and the freshwater inflow of Bhagirathi–Hooghly, Diamond Harbour appeared as an important coastal station of the Bhagirathi–Hooghly estuary. The spatial and temporal composition and abundance of microphytoplankton species was examined in relation to physical and chemical surface water variables (i.e., salinity, nutrient, and temperature).The primary objective of the study was to observe the variations in phytoplankton species assemblages as a response to environmental variables. Hierarchical cluster analysis and non-metric multidimensional scaling were used to find out distinct seasonal groups based on the composition of phytoplankton. The results indicate that several key environmental factors like temperature, DIN content, and molar ratio of nutrients like DIN–DIP and DIN–DSi influenced seasonal phytoplankton assemblages within the estuary. The distribution of phytoplankton population showed two main groups where the blue-green and green algal populations favored the warmer conditions of summer and monsoon months, whereas the diatom population primarily flourished in the cooler months of autumn and winter.

Composite algal supplementation in nutrition of Oreochromis mossambicus

Abstract: Composite algal mix has been used as feed supplement in nutrition of Oreochromis mossambicus and its effect on growth performance, feed efficiency, nutrient utilisation and body composition was investigated in a 12 week feeding trial. Three isonitrogenous diets containing 0 % (conventional feed, CF), 35% (value added feed, VAF) and 100% (algal feed, AF) algal supplementation were used in combination with other conventional fish feed ingredients. The algal genera used were Phormidium valderianum, Spirulina subsalsa, Navicula minima, Chlorococcum infusionum and Rhizoclonium riparium in a ratio of 35:35:12:12:6 for experimental feed formulation. Fish fed with VAF showed an increased growth performance (P < 0.05), feed efficiency and nutrient utilisation compared to 0 % and 100% supplemented diets. Carcass lipid levels decreased at 35% supplementation level. The results suggested that, 35 % supplementation of conventional feed with composite algal mix can be used in mossambique tilapia diet.

Effect of Formulated Algal Diet on growth performance of Labeo rohita Hamilton

Abstract: A 12-week laboratory feeding trial was performed to evaluate the efficacy of two different algae based value added feeds (one containing Spirulina platensis and Enteromorpha intestinalis and the other with Phormidium valderianum and Catenella repens) against conventional (rice bran and mustard oil cake taken in 2:1 ratio, used as control) for fingerlings of Indian major carp, Rohu (Labeo rohita, Cyprinidae). The feeds were formulated on the basis of crude protein requirement of Rohu. Proximate composition of the above mentioned algal genera and the formulated feeds was analyzed in respect to protein, carbohydrate, lipid, carotenoid and ash content. Evaluation of diets was carried out on the basis of feed intake rate, body weight gain percentage, feed conversion ratio, specific growth rate, metabolic growth rate, protein productive value, protein efficiency ratio, total muscle protein, lipid, carotenoid, ash content and accumulated muscle glycogen content. It was observed that the value added algal feed 2 was more suitable diet than the other two for Indian Major Carp L. rohita fingerling as evident from the growth performances. On the other hand, control diet resulted into high body lipid deposition which led to poor growth of the fishes.

Unusual habitat of algae

Abstract: In a recent survey of algal diversity from different habitat of Eastern India, 3 algal genera commonly occurring in aquatic habitat and in free living condition, viz. Chlorococcum and Cladophora of Chlorophyceae and Euglena of Euglenophyceae were recorded away from their usual habitat. Chlorococcum was found in endozoic condition within slug (mollusc without shell), Euglena in endophytic condition within the leaf of the pteridophytic genus Selaginella of Eastern Himalaya region and Cladophora was found to grow in terrestrial condition near the bank of the river Matla of the marine region of Sundarban mangrove forest of India.