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    Nitrogen acquisition in cyanobacteria
    (LAMBERT Academic Publishing, 2011) Bhagavatula, Vani
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    The Role of Cyanobacteria in Agriculture
    (Krishi Sanskriti Publications, 2015) Bhagavatula, Vani; Chowdhury, Shibasish
    Microorganisms offer a pool of properties which could be utilized for the benefit of the ecosystem and mankind. They have always played the central role in evolution and shaped out the existing life on earth. The population increase needs to keep pace with the agricultural front to meet the demands with supply. As the crops and other plants are sessile they have to combat biotic and abiotic stresses. The stressful environmental conditions including the stress, soil fertility issues, presence of pathogens etc. can hamper the growth and development of the plants and affect the crop productivity. These conditions could be regulated by using fertilizers specially biofertilizers, as the chemical fertilizers are effective but have deleterious effects on the ecosystem. This article focuses the role of cyanobacteria in agriculture to improve the crop yield. These photosynthetic prokaryotes fix the atmospheric nitrogen into utilizable form and make it available to the plants. They also form symbiotic associations and provide nourishment to the host and in turn get housing either endophytic or exophytic. The growth enhancement was observed when cyanobacteria were inoculated in the fields. This effect was due to hormones like cytokinin, gibberellins and auxin which accelerated growth. Elicitor molecules from these organisms like certain peptides, vitamins, carbohydrates are reported to induce pathogenesis in plants. The exo-polysaccharide of cyanobacteria improves the soil quality and fertility. The recent trend involves the manipulation of the higher plants with the genes from these organisms to improve their production and stress related properties.
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    Secondary metabolite production of cyanobacteria
    (IK Books, 2009) Verma, Sanjay Kumar
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    Nostoc calcicola Immobilized in Silica-coated Calcium Alginate and Silica Gel for Applications in Heavy Metal Biosorption
    (Springer, 2009) Verma, Sanjay Kumar
    The present study reports the preparation and characterization of silica-based immobilization matrices for the purpose of metal accumulation using immobilized cyanobacterium Nostoc calcicola. Silica gel was prepared using aqueous sodium silicate and colloidal silica. Calcium alginate (CAG) beads were coated with silica using sodium silicate solutions. Microscopy observations and TTC tests confirmed that the immobilized cells were intact and viable. Ultrastructural studies with electron microscopy revealed a membrane thickness of approximately 10 μm around the CAG and the silica gel to be of mesoporous nature. BET surface area of silica gel-immobilized N. calcicola was 160 m2 g−1. The porous volume and average pore diameter were 0.40 cm3 g−1 and ca. 100 Å, respectively, as calculated using the BJH model. Studies on silica-coated calcium alginate immobilized cells showed that these were superior to the uncoated CAG beads in terms of mechanical strength and metal accumulation. The silica matrices were found to be stable for repeated cycles of metal removal and with commonly used eluants for desorption processes. These matrices have potential applications in immobilization of industrially important biocatalysts.
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    Application of Direct Analysis in Real Time Mass Spectrometry (DART-MS) for Identification of an Epiphytic Cyanobacterium, Nostoc Sp.
    (Taylor & Francis, 2012-05-12) Verma, Sanjay Kumar
    Cyanobacteria, a diverse group of bacteria are identified entirely on the basis of morphological characters, which can frequently lead to incorrect results; therefore, the present study reports a new approach for identification of an organism based on DART technique. Direct Analysis in Real Time Mass Spectrometry (DART-MS) was used to identify a cyanobacterium, isolated from the leaf surface, on the basis of characteristic chemical compounds present in the strain. A chemical fingerprint was generated and peaks obtained were found to be similar to the masses of the compounds reported for Nostoc sp
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    Application of Mutant Strains of Cyanobacteria for Cd2+ Removal
    (Springer, 2002-11) Verma, Sanjay Kumar
    The current practice for the removal of soluble metal ions present in the industrial effluents includes simple chemical precipitation, ion exchange, ion specificity, narrow range of pH and poor settling colloidal properties may limit the effectiveness..
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    Evidences showing ultraviolet-B radiation-induced damage of DNA in cyanobacteria and its detection by PCR assay
    (Elsiever, 2004) Jha, Prabhat N.
    Ultraviolet-B (UV-B) radiation is a biologically effective component of solar radiation which because of its absorption by important biomolecules such as nucleic acids, proteins, and lipids causes deleterious effects on biological systems [1], [2]. It has now been well documented that depletion of stratospheric ozone has led to an increase in the level of ultraviolet-B radiation (280–320 nm) reaching the earth’s surface [3], [4] and has caused a risk of exposure of living organisms on the Earth to this harmful radiation [1], [5], [6], [7], [8]. Several studies conducted under laboratory and natural conditions have revealed the harmful effects of UV-B radiation on growth, survival, motility, development, pigmentation, nutrient uptake, and various metabolic processes of cyanobacteria [2], [9]. These effects are in part due to the direct effect on membrane proteins, photosystem II, DNA, enzymes, growth regulators or due to indirect effect through the formation of reactive oxygen species. Amongst several targets of UV-B damage that have been identified, DNA and photosynthesis are recognized as the most predominant action sites [2], [6], [10]. Most of the information pertaining to induction of UV-induced DNA damage, their biological effects, and repair have been obtained by using short wavelength UV-C radiation (254 nm). In general during the course of UV irradiation, photons are absorbed by the DNA causing several types of damage involving single bases or interaction between adjacent bases or between DNA and protein [5], [10], [11], [12], [13]. The main class of UV-induced lesions consists of dimeric pyrimidine photoproducts which distort the DNA helix. These include cyclobutyl pyrimidine dimers arising from the cycloaddition of C5–C6 double bond of two adjacent pyrimidines and the pyrimidine (6-4) pyrimidone adducts which result from the addition of the 5′ end pyrimidine to the C4 carbonyl or imine group of the 3′ end pyrimidine [5], [12]. The latter are produced at a much slower rate but unlike the former cannot be excised and repaired by the usual photoreactivation mechanisms and thus they have the capacity for longer term damage. The dimers block the action of DNA polymerase and thereby prevent genome replication [14], [15], [16]. This may consequently lead to delayed cell division and growth inhibition and ultimately to death.