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Study of soil cyanobacteria along a rural-urban gradient
(Elsevier B.V., 2018) Pradeep Kumar Rai; Anuradha Rai; Naveen Kumar Sharma; Surendra Singh
Urbanization is one of the modern and critical factors adversely affecting global biodiversity. The impact of urbanization on soil microbial diversity has sporadically been studied of cyanobacterial diversity. The present study analyzes morphological as well as molecular diversity of cyanobacteria along a rural-urban gradient using a culture based approach. In total, 22 cyanobacterial morphotypes (14 genera and 21 species) from five orders were reported; dominated by the members of the order Nostocales. In general, cyanobacterial diversity decreased from rural to urban areas; with N2-fixing heterocystous forms dominating the cyanobacterial flora of the urban area. The values of Shannon–Weaver (2.56) and Simpson's (2.32) indices suggested higher cyanobacterial diversity in the rural area compared to that of the sub-urban and urban areas. Statistical analyses established the importance of physico-chemical factors in structuring the cyanobcaterial communities along the gradient with soil characteristics such as – pH, organic carbon, nitrogen and bulk density, directly as well as indirectly. © 2018 Elsevier B.V.
Cyanobacteria: a key player in nutrient cycling
(Elsevier, 2023) Alka Bhardwaj; Prashansa Singh; Neha Gupta; Samujjal Bhattacharjee; Ankit Srivastava; Anirbana Parida; Arun Kumar Mishra
Cyanobacteria are photosynthetic prokaryotic organisms that are found in various aquatic and terrestrial environments. They are one of the oldest and most primitive forms of life on Earth, playing critical role in the biological nutrient cycling of different habitats. The phenomenon of nutrient cycling delineates the continual recycling of essential elements, which are rendered accessible to the biota of an ecosystem. Cyanobacteria possess the ability to fixate atmospheric nitrogen and transform it into a bioavailable form, which can be utilized by other organisms in the ecosystem. This process is called nitrogen fixation, and it helps to increase the availability of nitrogen in the ecosystem, which is an essential nutrient for the growth of different life forms. They also play a key role in carbon cycling by capturing carbon dioxide through photosynthesis and releasing oxygen into the atmosphere. Indeed, cyanobacteria played a significant role in making the early environment aerobic by producing oxygen through photosynthesis. This process helps to regulate the amount of carbon dioxide in the atmosphere, which is important for mitigating the effects of climate change. Additionally, cyanobacteria can contribute to the cycling of other nutrients, such as phosphorus and sulfur, by releasing them from organic matter and making them available for other organisms to use. Overall, cyanobacteria are crucial for the cycling of different nutrients, including nitrogen, carbon, phosphorus, and sulfur, and their impact on the health of the ecosystem cannot be overstated. The presence of these microorganisms is essential for ensuring a stable and thriving environment, and their involvement in nutrient cycling and oxygenic photosynthesis has constituted a critical component in the evolutionary history of life on Earth. © 2024 Elsevier Inc. All rights reserved.
Proteomics and Bioinformatics Approaches for Exploring Resilience Strategies in Cyanobacteria
(Springer Science+Business Media, 2025) Minu Kesheri; Swarna Kanchan; Donat Peter Häder; Rajeshwar Prasad Sinha
This chapter envisages the responses of cyanobacteria to different abiotic stresses with special reference to the cyanobacterium Scytonema tolypothrichoides VB-61278. We describe the in silico approach to compare Fe and Mn Super Oxide Dismutase (SOD) for deciphering their role in promoting resilience in Scytonema tolypothrichoides VB-61278. Various physicochemical parameters such as molecular weight, instability index, isoelectric point (pI), aliphatic index, and GRand Average of Hydropathy (GRAVY) were predicted and explained in an illustrative manner. The secondary structure of the protein was predicted followed by the prediction of three-dimensional (3D) structural models using Modeller and trailblazing artificial intelligence (AI)-powered AlphaFold2 tools have been illustrated. Exhaustive explanations of validation methods for the models using Prosa-web, Verify-3D, Ramachandran plot, and LDDT score have been highlighted. Studies emphasizing the conservation and prediction of metal binding positions, domains, and motifs, along with residues of structural and functional importance, as well as the generation of phylogenetic trees, have been well explained. This chapter serves as a state-of-the-art about methodologies, ensuing results, and inferences drawn from tools used in bioinformatics to decipher protein modeling and relevant biotechnological applications in a lucid and illustrative way. © 2025 The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Cyanobacteria in Diverse Habitats
(Elsevier, 2018) Lira A. Gaysina; Aniket Saraf; Prashant Singh
Cyanobacteria are an enormously diverse group of prokaryotes whose adaptive capacity along with the ability to tolerate extreme conditions makes them omnipresent. They are found in almost all the habitats of the Earth where life can be imagined to have flourished. Cyanobacteria are present in a wide range of habitats viz. marine, freshwater, soil, biological soil crusts, snow, cryoconites, etc. Further, they are found in symbiotic association with different hosts and also occur in extreme stressed conditions like volcanic ash, salted soils, and anthropogenically disturbed areas. This chapter explores the diversity of cyanobacteria from different habitats and enlists the dominant groups inhabiting these habitats. The diversity of cyanobacteria from different climatic zones; temperate, tropical as well as Polar Regions have been reviewed and documented in this chapter. The taxonomic complexity of cyanobacteria has hindered the capture of the actual biodiversity which is evident from the fact that the reported diversity encompasses only the traditional cyanobacterial genera. Morphological plasticity, ecological flexibility, and huge amount of heterogeneity are responsible for the confusions surfacing the cyanobacterial taxonomy. In this chapter, we also discuss the current trends in cyanobacterial taxonomy which would be essential in the studies conducted to capture the biodiversity of cyanobacteria from different habitats. © 2019 Elsevier Inc. All rights reserved.
The impacts of UV-B radiation on the enzymes of nitrogen metabolism in cyanobacteria
(Nova Science Publishers, Inc., 2018) Abha Pandey; Haseen Ahmed; Deepak K. Singh; Vidya Singh; Deepak Kumar; Rajneesh; Jainendra Pathak; Shailendra P. Singh; Rajeshwar P. Sinha
Nitrogen-fixing cyanobacteria possess a central position in the nutrient cycling largely due to their inherent capacity to fix atmospheric nitrogen directly into ammonium, with the help of the enzyme “nitrogenase” thus making it available for use by higher plants. The percentage of total annual ecosystem nitrogen input due to biological nitrogen fixation by cyanobacteria might be as high as 80% and the contribution to total annual nitrogen uptake by plants up to 20%. Recent global climate models predict a further significant loss of stratospheric ozone in the next decades, resulting in an increase in ultraviolet-B (UV-B) radiation reaching the surface of the Earth. UV-B radiation has deleterious effects on a number of metabolic processes such as growth, survival, pigmentation, phycobiliprotein composition, pigmentation, motility, heterocyst differentiation, 14CO2 uptake and enzymes of nitrogen metabolism in cyanobacteria, as well as several other freshwater and marine phytoplanktons. UV-B-induced stress can interfere with the metabolism of inorganic and organic nitrogen compounds. It affects several points of inorganic nitrogen assimilation pathway in cyanobacteria. UV exposure results in complete inhibition of nitrogenase activity and thus nitrogen-fixing activity is usually inhibited or depressed by UV-B-induced stress in most cyanobacteria. UV-B radiation has been reported to inhibit ammonium (NH4 +) and nitrite (NO2 -) uptake rates. In contrast, a significant increase in nitrate (NO3 -) uptake has been observed under UV-B stress. The activities of nitrate assimilating enzyme, nitrite reductase (NiR), and ammonium assimilating enzymes, glutamine synthetase (GS) and glutamate synthase (GOGAT) are also adversely affected on exposure to UV-B irradiation while nitrate reductase (NR) and glutamate dehydrogenase (GDH; aminating) show a stimulatory response. In this chapter we address the impacts of UV-B radiation on the various enzymes associated with nitrogen metabolism in cyanobacteria. © 2018 Nova Science Publishers, Inc.
Field evaluations of agrochemical toxicity to cyanobacteria in rice field ecosystem: a review
(Springer Netherlands, 2019) Manish Singh Kaushik; Ajay Kumar; Gerard Abraham; Nalinaxya Prasad Dash; Pawan Kumar Singh
The adverse effects of chemical nitrogen fertilizers affecting soil fertility, water pollution and native microorganisms, particularly cyanobacteria, in wetland rice cultivation have drawn global attention towards the use of alternative sources like N 2 -fixing cyanobacteria as a biofertilizer for sustainable rice farming. Although chemical nitrogen fertilizers are extensively used for obtaining higher rice yield, they are likely to have a deleterious effect on the growth and N 2 -fixation of diazotrophs, including cyanobacteria. In addition, biocides (herbicides and insecticides) are widely being used in rice cultivation for optimizing crop yield, but these chemicals also affects non-target organisms adversely. There are several reports indicating impacts of these agrochemicals on cyanobacteria, but most such studies were carried out under laboratory conditions. This article reviews information from different field evaluations on the impact of agrochemicals on cyanobacteria along with rice crop in wetland rice field ecosystem. © 2018, Springer Nature B.V.
Genetic regulation of scytonemin and mycosporine-like amino acids (MAAs) biosynthesis in cyanobacteria
(Elsevier B.V., 2019) Jainendra Pathak; Haseen Ahmed; Rajneesh; Shailendra P. Singh; Donat-P. Häder; Rajeshwar P. Sinha
Scytonemin and mycosporine-like amino acids (MAAs) are important novel secondary metabolites synthesized by cyanobacteria to protect themselves from lethal ultraviolet (UV) radiation. Scytonemin, the extracellular polysaccharide sheath pigment is found in several cyanobacterial species and is a lipid-soluble dimeric pigment consisting of phenolic and indolic subunits linked through an olefinic carbon atom. Structure of MAAs consists of aminocyclohexenone or an aminocyclohexinimine chrompohore conjugated with the nitrogen substituent of an amino acid or its amino alcohol. MAAs are small, colorless water soluble compounds. These UV screening compounds are highly photostable photoprotectant and also serve as potent antioxidants. Multiple environmental signals influence scytonemin and MAAs synthesis and regulation of induction of these UV screening compounds is a part of complex stress response pathway. Hence, proper understanding of genetic regulation and biosynthesis of these microbial sunscreens would not only provide scientific insight in a major class of secondary metabolites but will also help in commercial production of these new age ecofriendly sunscreens. © 2019
Roadmap to sustainable carbon-neutral energy and environment: can we cross the barrier of biomass productivity?
(Springer Science and Business Media Deutschland GmbH, 2021) Pankaj Kumar Maurya; Soumila Mondal; Vinod Kumar; Shailendra Pratap Singh
The total number of inhabitants on the Earth is estimated to cross a record number of 9 × 103 million by 2050 that present a unique challenge to provide energy and clean environment to every individual. The growth in population results in a change of land use, and greenhouse gas emission due to increased industrialization and transportation. Energy consumption affects the quality of the environment by adding carbon dioxide and other pollutants to the atmosphere. This leads to oceanic acidification and other environmental fluctuations due to global climate change. Concurrently, speedy utilization of known conventional fuel reservoirs causes a challenge to a sustainable supply of energy. Therefore, an alternate energy resource is required that can maintain the sustainability of energy and environment. Among different alternatives, energy production from high carbon dioxide capturing photosynthetic aquatic microbes is an emerging technology to clean environment and produce carbon-neutral energy from their hydrocarbon-rich biomass. However, economical challenges due to low biomass production still prevent the commercialization of bioenergy. In this work, we review the impact of fossil fuels burning, which is predominantly used to fulfill global energy demand, on the quality of the environment. We also assess the status of biofuel production and utilization and discuss its potential to clean the environment. The complications associated with biofuel manufacturing using photosynthetic microorganisms are discussed and directed evolution for targeted phenotypes and targeted delivery of nutrients are proposed as potential strategies to increase the biomass production. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Flow Cytometry-based Measurement of Reactive Oxygen Species in Cyanobacteria
(Bio-protocol LLC, 2022) Soumila Mondal; Shailendra P. Singh
Cyanobacteria are Gram-negative oxygen-producing photosynthetic bacteria that are useful in the pharmaceutical and biofuel industries. Monitoring of oxidative stress under fluctuating environmental conditions is important for determining the fitness, survival, and growth of cyanobacteria in the laboratory as well as in large scale cultivation systems. Here, we provide a protocol developed using unicellular Synechococcus elongatus PCC 7942 and filamentous Fremyella diplosiphon BK14 cyanobacteria for high-throughput oxidative stress measurement by 2′,7′-dichlorodihydrofluorescein-diacetate (DCFH-DA) and flow cytometry (FCM). We also provide details for the optimization of cell number, dye concentration, and FCM parameters for each organism before it can be utilized to quantify reactive oxygen species (ROS). FCM-based method can be used to measure ROS in a large population of cyanobacterial cells in a high-throughput manner. © 2022 The Authors; exclusive licensee Bio-protocol LLC.
Molecular characterization of hot spring cyanobacteria and evaluation of their photoprotective compounds
(2012) Rajesh P. Rastogi; Sunita Kumari; Richa; Taejun Han; Rajeshwar P. Sinha
Phylogenetic analysis of 4 cyanobacterial strains isolated from hot springs in Rajgir, India, was carried out using the 16S rRNA gene (1400 bp). These strains were identified as members of Chroococcales (Cyanothece sp. strain HKAR-1) and Nostocales (Nostoc sp. strain HKAR-2, Scytonema sp. strain HKAR-3, and Rivularia sp. strain HKAR-4). Furthermore, we evaluated the presence of ultraviolet-screening and (or) photoprotective compounds, such as mycosporine-like amino acids (MAAs) and scytonemin, in these cyanobacteria by using high-performance liquid chromatography. Well-characterized MAAs, including the critical and highly polar compounds shinorine, porphyra-334, and mycosporine-glycine, as well as several unknown MAAs, were found in these hot-spring-inhabiting microorganisms. The presence of scytonemin was detected only in Scytonema sp. strain HKAR-3 and Rivularia sp. strain HKAR-4. The results indicate that hot spring cyanobacteria, namely Cyanothece, Nostoc, Scytonema, and Rivularia, belonging to different groups possess various photoprotective compounds to cope up with the negative impacts of damaging radiations.

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