Systematic and ecological studies on Chlorophyceae of North India and their relationship with water quality

In the course of systematic and ecological studies on algal flora of fresh water environment of three different agroclimatic zone of Uttar Pradesh revealed one hundred eighty two species represented by fifty-two genera inhabiting fresh water bodies having different physico-chemical properties. In both the regions members of order Conjugales were dominant and represented by ninety nine species belonging to fourteen genera. This is followed by Chlorococcales having fifty two species represented by nineteen genera and Chaetophorales with nine species of four genera only. In the central Uttar Pradesh a positive correlation was found between hydrogen ions concentration with temperature and species diversity, while in western Uttar Pradesh a highly positive correlation was found in electrical conductivity and total dissolved solids.     

Design of reaction conditions for the enhancement of microbial degradation of dyes in sequential cycles

The present study evaluated the potential of white-rot fungal strain Coriolus versicolor to decolorize five structurally di erent dyes in sequential batch reactors under optimized conditions. The experiments were run continuously for seven cycles of 8 d each. High decolorizing activity was observed even during the repeated reuse of the fungus, especially when the old medium was replaced with fresh medium after every cycle. Biodegradation was the dominating factor as the fungus was able to produce the enzyme laccase mainly, to mineralize synthetic dyes. The nutrients and composition of the medium played important roles in sustaining the decolorisation potential of the fungus. Corncob was found be an easy and cheap substitute for carbon source for the fungus. Glucose consumption by the fungus was in accordance to its decolorisation activity and chemical oxygen demand (COD) reduction.     

Free radical biology in neurological manifestations: mechanisms to therapeutics interventions

Environmental Science and Pollution Research - Recent advancements and growing attention about free radicals (ROS) and redox signaling enable the scientific fraternity to consider their involvement...     

Rice seedlings under cadmium stress: effect of silicon on growth,cadmium uptake,oxidative stress,antioxidant capacity and root and leaf structures

In this study, the effect of silicon (Si) addition on cadmium (Cd) toxicity in rice seedlings was investigated. After a series of screening experiments, 50 μmol·L^?1 of Cd and 10 μ mol·L^?1 of Si were selected. Treatment of rice seedlings with Cd (50 μ mol·L^?1) resulted in significant accumulation of this metal in roots and shoots. The data revealed that accumulation of Cd resulted in oxidative stress in rice seedlings as evidenced by increased accumulation of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA; a peroxidation product of lipids). However, addition of Si (10 μ mol·L^?1) together with Cd prevented accumulation of Cd, H₂O₂ and MDA. Antioxidant capacity was decreased by Cd but enhanced by Si addition. Cd decreased the length and frequency of root hairs, stomatal frequency, and distorted leaf mesophyll cells and vascular bundles. However, addition of Si together with Cd reduced these abnormalities. The results showed that addition of exogenous Si protected rice seedlings against Cd toxicity by preventing Cd accumulation and oxidative stress (H₂O₂ and MDA accumulation) by increasing Si accumulation and antioxidant capacity, which maintained the structure and integrity of leaf and root.     

Evaluation and sensitivity of cyanobacteria,Nostoc muscorum and Synechococcus PCC 7942 for heavy metals stress – a step toward biosensor

This study attempted to determine the effects of heavy metals on the photosynthetic blue-green algae for their potential to use as a biosensor. The bioaccumulation of metals and its effects on pigments of Nostoc muscorum and Synechococcus PCC 7942 were assessed. The culture was grown in BG 11 liquid medium supplied with different metals like mercury (Hg), lead (Pb), and cadmium (Cd) and incubated (µM 20 concentrations) for 10 days under optimal conditions. The accumulated amounts of metals were determined by atomic absorption spectroscopy (AAS). The stress effects on photosynthetic pigment chlorophyll a (Chl a) were monitored by laser-induced fluorescence (LIF). Bio-concentration factor (BCF) reached a peak in cells on the 2nd day of incubation followed by a gradual reduction. The highest reduction in the pigment concentrations (Chl a and β carotene) was observed at 20?µM?L^?1 Hg treatment. The results indicate that, cyanobacteria may serve as both potential species to be used as a biosensor and used to clean up heavy metals from contaminated water. These changes were analyzed with the long-term goal of exploiting cyanobacterial cells as biosensors.     

Enhancement in biodegradability of distillery wastewater using enzymatic pretreatment

A combined treatment technique consisting of enzymatic hydrolysis, followed by aerobic biological oxidation was investigated for the treatment of alcohol distillery spent wash. The enzyme cellulase was used for the pretreatment step with an intention of transforming the complex and large pollutant molecules into simpler biologically assimilable smaller molecules. Batch experiments were performed in order to analyze the influence of various parameters like pretreatment time, enzyme concentration and pH during the pretreatment step on the subsequent aerobic oxidation kinetics. The rate of aerobic oxidation was enhanced by 2.3 fold for the pretreated sample as compared to the untreated sample when the pH during the pretreatment step was maintained at a value of 4.8. Similarly, a two fold increase in the aerobic oxidation rate was found when the effluent was pretreated with the enzyme, without any pH control (i.e. effluent pH of 3,8). The study indicated that the enzymatic pretreatment of the effluent could be one of the successful pretreatments which can lead to enhancement of the rate of the subsequent aerobic oxidation.     

Alterations in aerobic and anaerobic dehydrogenases and protein levels of three tropical earthworm species with respect to different seasons

The specific activities of cMDH, mMDH and LDH of earthworms (M. posthuma, P. sansibaricus, L. mauritii) started increasing with the onset of favorable seasonal conditions from July to August. A lower temperature and moisture favor the increase in specific activities of enzymes during post-rainy (September–October) and winter (November–January) seasons. The maximum specific activities of enzymes from December to January indicate greater aerobic and anaerobic energy production to cope up with the cold condition. However, the enzyme activities decreased in summer (February–April) with the increase in the ambient temperature. The specific activities were minimum in summer (May–June) as earthworms would be entering quiescent phase to avoid extreme heat and thus showed least energy requirement in this period. Similar seasonal variations were found in the cytoplasmic and mitochondrial proteins. The maximum and minimum seasonal effects were on the epigeic (P. sansibaricus) and endo-anecic (M. posthuma) earthworms, respectively. The differences in the profile of dehydrogenases and proteins may be assigned to the differences in the ecological categories of earthworms.     

Habitat-associated changes in some metabolic dehydrogenases and proteins of tropical earthworms

Impacts of different habitats on specific activities of LDH, cMDH, mMDH, cytoplasmic and mitochondrial proteins of M. posthuma, P. sansibaricus, L. mauritii were studied. Maximum specific activity of LDH of the earthworm M. posthuma and L. mauritii was observed in garden. In case of P. sansibaricus, maximum LDH specific activity was found in sewage. Minimum specific activity of LDH of the earthworm M. posthuma was found in non-cultivated field. However, P. sansibaricus and L. mauritii exhibited minimum activity in orchard and cultivated pedoecosystem, respectively. The maximum specific activity of cMDH and mMDH in earthworms from sewage and minimum from non-cultivated field (in case of M. posthuma), garden (in P. sansibaricus) and cultivated land (in L. mauritii) may be due to availability of more organic matter and nitrogen content in the former than in the later cases. Variations in specific activities of these metabolic enzymes due to changes in their pedoecological habitats clearly demonstrate the impact of pedoecosystem on respiratory capacity of the earthworms. Earthworms from pedoecosystem richer in organic matter and nitrogen showed elevated levels of cytoplasmic and mitochondrial protein. The changes in enzyme-specific activity and protein profiles were habitat specific.     

Dechlorination of chloroorganics,decolorization, and simultaneous bioremediation of Cr6+ from real tannery effluent employing indigenous Bacillus cereus isolate

A native Bacillus cereus isolate has been employed, for the first time, for simultaneous decolorization, dechlorination of chloroorganics, and Cr⁶⁺ remediation from the real tannery effluent. Most of the physicochemical variables in 3:1 diluted effluent were well above the standard prescribed limits, which decreased substantially upon microbial treatment. The extent of bioremediation was better in diluted (3:1) as compared to undiluted effluent supplemented with nutrients and augmented with B. cereus isolate. Maximum growth, effluent decolorization (42.5 %), dechlorination (74.1 %), and Cr⁶⁺ remediation (34.2 %) were attained with 4.0 % (v/v) inoculum, 0.8 % glucose, and 0.2 % ammonium chloride in 3:1 diluted effluent at natural pH (8.1) within 72 h of incubation. The efficiency of bioremediation in a bioreactor was higher as compared to a flask trial during 72 h of incubation: decolorization (47.9 %) was enhanced by 5.4 %, dechlorination (77.4 %) by 3.3 %, and Cr⁶⁺ removal (41.7 %) by 7.5 % at an initial color of 286 Pt-Co units and initial concentration of 62 mg chloride ions and 108 mg l^?1 Cr⁶⁺. Immobilized biomass of Pseudomonas putida and B. cereus coculture enhanced the extent of Cr⁶⁺ remediation (51.9 %) by 10.2 % compared to the bioreactor trial. Chromate reductase activity and reduced Cr directly correlated and were mainly associated with soluble fraction of B. cereus plus effluent natural microflora. The GC-MS analyses revealed the formation of metabolites such as acetic acid and 2-butenoic acid in bacterially treated effluent. The supplementation of nutrients along with B. cereus augmentation is required for efficient effluent bioremediation.