Extracellular antibacterial substances in Anabaena fertilissima CCC597 kill bacteria by triggering oxidative radicals and destroying membrane integrity

An axenic culture of a cyanobacterium in the spent medium produced hexane-extracta- ble compound(s) that antagonized growth of several Gram+ve and –ve bacteria, including a few potential pathogens. Phylogenetic investigations classified the strain to be Anabaena fertilissima strain CCC597. Using Escherichia coli MTCC443 as a test organism, we have shown that ROS (O 2; H 2O 2) production and outer and inner membrane (OM: IM) permeabilization were induced upon such treatments. Consequently, leakage of proteins and cytosolic acidification processes were initi- ated. Suppression of cytoplasmic membrane-bound respiratory O 2consumption was most likely the physiological aberration that killed the bacteria. Several antioxidant enzymes viz. superoxide dis- mutase, catalase, and peroxidases showed concomitant increase in the enzymatic activities and band intensities in the corresponding substrate gels. Notwithstanding, the counteraction mechanism(s) was not preventive, and sufficient oxidative radicals still generated to manifest lipid peroxidation. Chemical analysis of the hexane-extract of A. fertilissima culture filtrates revealed presence of a number of long chain unsaturated fatty acids, including cis-13,16-docosadienoic acid, with proven antibacterial properties.

Effects of Cyanobacterial Inoculation on the Growth and Yield of Triticum aestivum L. var. Deva K9117

The exponential growth in human population is become a serious concern in terms of their nutritional requirements. For the solution of this problem several methods and technologies have been adopted like development of high yielding varieties with improved agricultural practices. These varieties require more chemical fertilizers for the maximum production but excessive utilization of these chemical fertilizers may cause the deficiencies and infertility in the agricultural soils. So there is need to replace these chemical fertilizers with biological fertilizers due to their environmental sustainability. The utilization of cyanobacteria as bio-fertilizers are an eco-friendly, easily manageable and self-regenerating process which improve the nutrient status as well as health of soil. In addition to biological nitrogen fixation they also produce several growth promoting substances. During the present investigations we have adopted an experimental research approach to examine the effects of cyanobacteria (inoculation of live Anabaena fertilissima C.B. Rao and Nostoc linckia Bornet ex Bornet and Flahault isolates collected from river Ganga at Kanpur, U.P, India) as bio-fertilizer in Triticum aestivum L. var. Deva K9117 on the basis of average height of plants, weight of grains and number of grains/spike. The observations showed significant changes/improvements in growth and productivity of Triticum aestivum L. var. Deva K9117. The inoculation of Anabaena fertilissima C.B. Rao (100 ml) increased the 19.81% grains/spike, 9.86% weight of grains and 7.91% height of plants while inoculation of Nostoc linckia Bornet ex Bornet and Flahault (100 ml) increased the 19.36% grains/spike, 7.27% weight of grains and 5.64% height of plants over the control. The most considerable finding of the study was the mixture of Anabaena fertilissima C.B. Rao+Nostoc linckia Bornet ex Bornet and Flahault (60:40) increased 24.32% grains/spike, 15.09% weight of grains and 10.09% height of plants over the control.

Consequences of Environmentally Hazardous Polycyclic Aromatic Hydrocarbon- Anthracene Treatment on Cyanobacteria

The study was aimed to determine the chronic toxicity of Polynuclear aromatic hydrocarbon – Anthracene in response to pigments and metabolic study on three different cyanobacterial species such as Synechocystis sp., Anabaena fertilissima, and Nostoc muscorum. Test organisms were treated at different doses and encountered LC50/Mean Lethal Concentration (at which 50% lethality/ growth reduction occur) separately at 7.0 ppm for Synechocystis sp, 5.0 ppm for Anabaena fertilissima and 1.5 ppm for Nostoc muscorum. The influence of anthracene on pigments, metabolites and enzymes was carried out. The test doses caused concentration dependent and decreased pigments like carotenoids and phycobilliproteins. Depletion of carbohydrate by 65 to 80% and proteins by 58 to 78% was encountered with rise in Anthracene concentrations after 16th day exposure in case of Synechocystis sp however, phenols were found to raise by 26 to 37% with increased anthracene concentrations. Similar trend also observed in other two tested blue green algae. Thus the Synechocystis sp.is more tolerant to anthracene treatments as compare to Anabaena fertillissima but Nostoc muscorum showed highest sensitivity to anthracene.Int J Appl Sci Biotechnol, Vol 3(3): 381-386

Chronic Toxicity Of High Molecular Weight Polynuclear Aromatic Hydrocarbon- Pyrene On Freshwater Cyanobacterium Anabaena Fertlissima Rao

The aim of this work was to determine the consequences of Polynuclear aromatic hydrocarbon – Pyrene in response to growth, pigments and metabolic study on Anabaena fertilissima Rao. Test organisms were treated at different doses and encountered LC50 (Lethal concentration at which 50% growth reduction occur) concentration separately at 1.5 mg/l, 3.0 mg/l and 6.0 mg/l respectively for Anabaena fertilissima Rao. The influence of Pyrene on growth, pigments, release of metabolites such as carbohydrates, protein, amino acid, phenols was carried out. The test doses caused a concentration dependent decrease in pigments like carotenoids and phycobilliproteins and showed more sensitivity to pyrene. Depletion of carbohydrate by 13% to 81% and proteins by 47% to 93% was encountered with rise in pyrene concentrations after 16th day of exposure. However, phenols were found to rise by 27% to 50% with increased pyrene concentrations on the contrary, amino acids were reported to decline by 79% to 92%. This study therefore suggests high molecular weight pyrene that decreases in metabolite content and enzyme activity can be used as a signal of PAHs toxicity in cyanobacteria. International Journal of Environment, Volume-2, Issue-1, Sep-Nov 2013, Pages 175-183 DOI: http://dx.doi.org/10.3126/ije.v2i1.9220