Browsing by Author "Anjali Gupta"

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Carbon concentrating mechanism in cyanobacteria: necessity and evolution
(Elsevier, 2023) Priyul Pandey; Rinkesh Gupta; Sapna Tiwari; Anjali Gupta; Soumila Mondal; Rajeshwar P. Sinha; Shailendra P. Singh
Cyanobacteria are Gram-negative photosynthetic bacteria that produce oxygen similar to eukaryotic algae and higher plants during photosynthesis. These prokaryotes appeared on the Earth when there was no oxygen in the atmosphere, and oxygen produced by them led to the development of present-day aerobic life. However, cyanobacteria lack any subcellular organelles like a nucleus, chloroplast, and mitochondria, and therefore the evolution of the ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) enzyme in the presence of oxygen resulted in the oxygenase activity. Also, CO2 is limiting in aquatic environments where it is readily available in the form of bicarbonate (HCO3 ¯). Thus the oxygenase activity of Rubisco and availability of HCO3 ¯ acted as a selection pressure in the cyanobacteria for the evolution of an efficient CO2 concentrating mechanism (CCM) to minimize photorespiration and utilization of available forms of inorganic carbon. In this chapter, we will discuss different components of cyanobacterial CCM such as carboxysome, carbonic anhydrase, and inorganic carbon transporters. We have also included information on evolutionary pressure that resulted in the development of CCM in cyanobacteria. © 2024 Elsevier Inc. All rights reserved.
Cyanobacterial green chemistry: a blue-green approach for a sustainable environment, energy, and chemical production
(Royal Society of Chemistry, 2025) Priyul Pandey; Deepa Pandey; Anjali Gupta; Rinkesh Gupta; Sapna Tiwari; Shailendra P. Singh
Increased human activity due to the ever-increasing global population has necessitated the urgent need for a sustainable environment, food, and energy. Cyanobacteria, classically known as blue-green algae, are oxygen-producing photosynthetic organisms that are emerging as an option to achieve sustainable development goals. These Gram-negative prokaryotes can efficiently sequester atmospheric CO2 due to an efficient carbon concentrating mechanism and divert it to the production of energy-rich compounds, i.e., biofuel, and other valuable chemicals, using their flexible metabolic chassis. Additionally, cyanobacteria also minimize the emission of methane, which is another greenhouse gas, by providing oxygen to methane-oxidizing bacteria. In recent years, several genetically engineered strains of cyanobacteria have been developed that can produce biofuels and several other valuable chemicals. Strains have also been engineered for bioplastic production and bioremediation purposes. These organisms have gained attention as biofertilizers and can increase the quality and fertility of soil. Thus, cyanobacteria are promising CO2 sinks that can contribute to global efforts in carbon capture and storage initiatives while producing bioenergy, cosmetics, pharmaceuticals, and several other valuable chemicals. Therefore, these blue-green cells can be used for green chemistry while minimizing the atmospheric CO2 concentration. In this review, we present various applications of cyanobacterial biomass to achieve sustainable development goals. We also discuss challenges associated with the wide application of cyanobacteria and the future direction to make full use of these robust organisms to fulfill our future demands in an environment-friendly manner. © 2025 The Author(s)
Estimation of Growth and Photosynthetic Pigments in Cyanobacteria
(CRC Press, 2024) Pankaj K. Maurya; Sapna Tiwari; Soumila Mondal; Anjali Gupta; Shailendra P. Singh
The first oxygenic photosynthesis on the Earth was performed by cyanobacteria during the Precambrian period. These Gram-negative bacteria are cosmopolitan in distribution and play an important role in any ecosystem because of their inherent ability to fix carbon dioxide and dinitrogen (Bryant 1994). Due to their photoautotrophic mode of nutrition, cyanobacteria have an obligatory requirement for the harvesting of solar radiation to produce adenosine triphosphate (ATP) and NADPH2. © 2024 selection and editorial matter, Shailendra P. Singh, Rajeshwar P. Sinha and Donat-P. Häder; individual chapters, the contributors.
Flow Cytometry–Based Methods for Estimating DNA Content and Live-Dead Cells in Cyanobacteria
(CRC Press, 2024) Soumila Mondal; Anjali Gupta; Sapna Tiwari; Rinkesh Gupta; Shailendra P. Singh
Cyanobacteria are Gram-negative, photosynthetic, oxygen-producing bacteria that thrive in a variety of harsh environmental conditions (Whitton and Potts 2012). In addition to oxygen production, several cyanobacteria can fix atmospheric nitrogen due to the presence of nitrogenase enzymes. Therefore, cyanobacteria play an important role in sustaining life on Earth. Cyanobacteria are found in different morphological forms such as filamentous, unicellular and colonial forms. Filamentous forms generally show cellular differentiation during their development and may possess different cell types such as heterocysts for nitrogen fixation, akinetes as a resting stage cell and hormogonia as a reproductive short motile filament (Claessen et al. 2014; Herrero et al. 2016). Cyanobacteria are known for the production of industrially important metabolites and biofuels (Jones and Mayfield 2012; Neilan et al. 2013; Wijffels et al. 2013; Oliver and Atsumi 2014). © 2024 selection and editorial matter, Shailendra P. Singh, Rajeshwar P. Sinha and Donat-P. Häder; individual chapters, the contributors.
Genomic DNA and RNA Extraction from Cyanobacteria
(CRC Press, 2024) Anjali Gupta; Soumila Mondal; Sapna Tiwari; Donat-P. Häder; Rajeshwar P. Sinha; Shailendra P. Singh
Cyanobacteria are an ancient group of Gram-negative, oxygenic photoautotrophs that contribute significantly to global carbon dioxide (CO2) and nitrogen (N2) fixation (Falkowski 1997; Whitehead et al. 2014). Phenotypic characterization combined with nucleic acid sequence–based molecular approaches is used to identify and classify a wide range of cyanobacteria occurring in diverse habitats (De Clerck et al. 2013; Sharma et al. 2014). The first and most important step in the molecular characterization of cyanobacteria, or any other organism, is to extract a sufficient amount of genomic DNA of high quality, which is further used as a template for the amplification of target genes for sequencing and analysis. Also, cyanobacteria are emerging model systems for the production of valuable chemicals by metabolic engineering that require alteration in the genetic makeup of the organism (Angermayr et al. 2009; Atsumi et al. 2009; Lindberg et al. 2010; Aikawa et al. 2014). © 2024 selection and editorial matter, Shailendra P. Singh, Rajeshwar P. Sinha and Donat-P. Häder; individual chapters, the contributors.
LC-MS/MS–Based Proteomics Study of Cyanobacteria
(CRC Press, 2024) Soumila Mondal; Subodh Kumar; Phulen Sarma; Bikash Medhi; Anjali Gupta; Sapna Tiwari; Pankaj K. Maurya; Shailendra P. Singh
Cyanobacteria are a monophyletic group of Gram-negative, oxygen-producing photosynthetic microorganisms that are well known for their significant contribution to global CO2 and N2 fixation (Zahra et al. 2020). Several cyanobacteria can be easily genetically modified and have simple growth requirements as compared to algae and plants (Berla et al. 2013; Singh and Sinha 2020). A cyanobacterial biomass of a wild type as well as genetically engineered strains have commercial and industrial importance for the production of various secondary metabolites such as long-chain alcohols, alkanes, fatty acids, ethylene, 2,3-butanediol, ethanol, polyhydroxybutyrate and hydrogen (Knoot et al. 2018). Due to the obligatory requirement of light for their growth, cyanobacteria are exposed to a dynamic light environment, both diurnally and seasonally in their natural habitat, as well as in large-scale cultivation systems (Ooms et al. 2016). In addition to light, several other abiotic factors such as salinity, drought, temperature, pH and nutrient availability affect their overall fitness, growth and development. Also, installation of novel metabolic pathways and associated metabolite production could alter the overall regulatory network of the organism and its response to environmental factors (Ungerer et al. 2018; Gupta et al. 2020). Therefore, transcriptomics and proteomics studies have become important tools for the identification and quantification of transcriptomes and proteomes of native as well as genetically engineered strains to understand their response to different environmental conditions. However, information obtained from transcriptomic study may not necessarily translate to a protein level. Therefore, proteomic studies have emerged as a powerful tool to understand the total protein complement of any genome and its role as a part of a complex network system (Aebersold and Mann 2003; Karpievitch et al. 2010). © 2024 selection and editorial matter, Shailendra P. Singh, Rajeshwar P. Sinha and Donat-P. Häder; individual chapters, the contributors.
Light-dependent impact of salinity on the ecophysiology of Synechococcus elongatus PCC 7942: Genetic and comparative protein structure analyses of UV-absorbing mycosporine-like amino acids (MAAs) biosynthesis
(Elsevier B.V., 2021) Vinod Kumar; Soumila Mondal; Anjali Gupta; Pankaj K. Maurya; Rajeshwar P. Sinha; Donat-P. Häder; Shailendra P. Singh
Cyanobacteria are subjected to a dynamic light environment in their natural habitat or artificial cultivation system. The fluctuating light environment is associated with increased salinity stress due to the evaporation of the growth medium. Therefore, it is important to understand the physiology of the organisms under a dynamic environment of light and salinity which together affect the fitness and overall performance of the organism. We studied the growth behavior and other physiological parameters of Synechococcus elongatus PCC 7942 in the presence of different NaCl concentrations (0, 50, 100 and 200 mM) and light conditions such as low PAR (LPAR), high PAR (HPAR) and PAR + UVR using diurnal and continuous photoperiods. We also investigated the ability of S. elongatus PCC 7942 to biosynthesize UV-absorbing mycosporine-like amino acids (MAAs) and conducted genetic and comparative protein structure analyses to better understand its biosynthesis. Results obtained suggest that the impact of salinity stress caused by NaCl on growth behavior and physiological parameters such as photosynthetic pigments, the effective quantum yield of PSII and oxidative stress is dependent on the light environment. These parameters were affected differently by the quality and quantity of light and photoperiods, and the negative effect of salinity was alleviated by a high light environment. S. elongatus PCC 7942 does not biosynthesize MAAs due to the absence of MAAs biosynthesizing genes cluster in its genome. Results from genomic and comparative protein structure analyses suggested that DDGS and DHQS enzymes are different and DDGS but not DHQS is required for MAAs biosynthesis. Understanding the light-dependent impact of salinity stress may help in developing strategies for outdoor cultivation of cyanobacteria for bioenergy and valuable chemicals production by balancing absorbed and utilized radiant energy. © 2021 Elsevier B.V.
Methods for Estimation of Oxidative Stress Indices in Cyanobacteria
(CRC Press, 2024) Vinod Kumar; Anjali Gupta; Soumila Mondal; Sapna Tiwari; Shailendra P. Singh
Cyanobacteria are a primitive group of photosynthetic microorganisms that perform oxygenic photosynthesis in the presence of sunlight. These prokaryotes have emerged as model organisms in the last decade for the production of bioenergy and industrially important chemicals in a carbon-neutral manner (Pathak et al. 2018; Rajneesh et al. 2017). Cyanobacteria are also good sources of natural antioxidants that are produced as a protective mechanism against toxic reactive oxygen species (ROS) (Jerez-Martel et al. 2017; Guerreiro et al. 2020). Due to their photoautotrophic mode of nutrition, cyanobacteria experience seasonal and diurnal changes in quality and quantity of light, temperature, nutrient availability, CO2 levels, salinity and pH (Singh and Montgomery 2013; Kumar et al. 2021). © 2024 selection and editorial matter, Shailendra P. Singh, Rajeshwar P. Sinha and Donat-P. Häder; individual chapters, the contributors.
Monitoring Photosynthetic Performance in Cyanobacteria by a Modulated Fluorometer
(CRC Press, 2024) Sapna Tiwari; Pankaj K. Maurya; Soumila Mondal; Anjali Gupta; Donat-P. Häder; Shailendra P. Singh
Photoautotrophs are the only biological organisms that are capable of reducing atmospheric carbon dioxide (CO2) using sunlight as a source of energy during photosynthesis. Being the primary producers in the ecosystems, photoautotrophs are a suitable source of energy for higher trophic levels (Bryant 1994). In addition to higher plants, algae and cyanobacteria are the major contributors to the production of oxygen on the Earth. Also, these photosynthetic microorganisms are emerging as a model system for the sequestration of CO2 and production of biofuels and valuable chemicals in a carbon-neutral manner (Field et al. 1998a; Barber 2009; Maurya et al. 2021). Cyanobacteria, formerly known as blue-green algae, are oxygen-producing, photosynthetic, Gram-negative bacteria that use proteinaceous macrocomplexes called phycobilisomes (PBSs) for harvesting solar radiation to drive photosynthesis. PBSs are composed of chromophore-binding phycobiliproteins such as allophycocyanin (APC; λmax ∼650 nm), phycocyanin (PC; λmax ∼620 nm) and phycoerythrin (PE; λmax ∼565 nm) (Sanfilippo et al. 2019). © 2024 selection and editorial matter, Shailendra P. Singh, Rajeshwar P. Sinha and Donat-P. Häder; individual chapters, the contributors.
Photoacclimation strategies in cyanobacterial photosynthesis under dynamic light environments: implications in growth, fitness, and biotechnological applications
(Frontiers Media SA, 2025) Sapna Tiwari; Anjali Gupta; Deepa Pandey; Priyul Pandey; Rinkesh Gupta; Shailendra P. Singh
Cyanobacteria, ancient oxygenic photoautotrophs originated in the Precambrian period, exhibit remarkable adaptability to diverse ecological systems. Light, a critical environmental factor, exerts differential pressures on these organisms. The scattering of white light creates dynamic light environments, which poses a significant ecological challenge. To thrive in dynamic light environment, cyanobacteria have developed several light acclimation strategies. This includes chromatic acclimation, which optimize light harvesting by adjusting pigments. Cyanobacteria also employ robust photoprotective mechanisms against quantitative light stress. Under high light, these organisms activate non-photochemical quenching using the proteins such as orange carotenoid protein, iron starvation-induced protein, and high light-induced proteins to safely dissipate excess excitation energy. Additionally, thylakoid-localized respiratory enzymes alleviate electronic pressure arising from over-reduction of the plastoquinone pool. Under low light conditions, cyanobacteria frequently employ state transitions, reversibly associating their phycobilisomes with PSII and PSI to optimize light harvesting. These natural strategies offer a blueprint for engineering cyanobacteria and algae for their application in biomanufacturing and CO2 sequestration. This review synthesizes the key light acclimation and photoprotective mechanisms, underscoring their importance for both the ecological success of cyanobacteria and their implication in biotechnological applications using engineered strains. © © 2025 Tiwari, Gupta, Pandey, Pandey, Gupta and Singh.
Quantitative Estimation of Total Carbohydrate, Protein and Lipid Content in Cyanobacteria
(CRC Press, 2024) Pankaj K. Maurya; Sapna Tiwari; Soumila Mondal; Anjali Gupta; Vinod Kumar; Shailendra P. Singh
The continuous consumption of fossil fuel–based energy resources has threatened the sustainability of both the environment and energy supply (Houghton 2005). To overcome the negative impacts of fossil fuel burning on the energy supply and environment, biofuel production from the biomass of photoautotrophs has been advocated (Pinto et al. 2005; Rajneesh et al. 2017; Rodionova et al. 2017; Maurya et al. 2021). Depending on the source of the biomass, different generations (G) of biofuels such as 1G, 2G, 3G and 4G biofuels have been developed (Maurya et al. 2021). However, third and fourth generations of biofuel production from wild-type and genetically engineered strains, respectively, of microalgae and cyanobacteria have gained attention in the last two decades to avoid any competition for fertile land to produce food and energy (Pinto et al. 2005; Rodionova et al. 2017; Maurya et al. 2021). © 2024 selection and editorial matter, Shailendra P. Singh, Rajeshwar P. Sinha and Donat-P. Häder; individual chapters, the contributors.
Reactive Oxygen Species Measurement in Cyanobacteria Using 2′,7′-Dichlorodihydrofluorescein Diacetate (DCFH-DA) Dye and Fluorescence Microscope or Flow Cytometer
(CRC Press, 2024) Soumila Mondal; Anjali Gupta; Sapna Tiwari; Pankaj K. Maurya; Priyul Pandey; Shailendra P. Singh
Cyanobacteria are prokaryotic photosynthetic organisms that produce oxygen (O2) during photosynthesis similar to algae, bryophytes, pteridophytes, gymnosperms and angiosperms (Sánchez-Baracaldo and Cardona 2020). These Gram-negative bacteria have a long evolutionary history of survival under harsh environmental conditions that supported their presence in almost every ecological niche (Sinha and Häder 1996). Cyanobacteria possess different morphological forms like unicellular, unicellular colonial, differentiated and undifferentiated multicellular filamentous forms with true or false branching (Whitton and Potts 2012). Apart from O2 production, cyanobacteria contribute significantly to the productivity of aquatic and terrestrial ecosystems by fixing carbon dioxide (CO2) and nitrogen (N2). © 2024 selection and editorial matter, Shailendra P. Singh, Rajeshwar P. Sinha and Donat-P. Häder; individual chapters, the contributors.
Responding to light signals: a comprehensive update on photomorphogenesis in cyanobacteria
(Springer, 2023) Anjali Gupta; Priyul Pandey; Rinkesh Gupta; Sapna Tiwari; Shailendra Pratap Singh
Cyanobacteria are ancestors of chloroplast and perform oxygen-evolving photosynthesis similar to higher plants and algae. However, an obligatory requirement of photons for their growth results in the exposure of cyanobacteria to varying light conditions. Therefore, the light environment could act as a signal to drive the developmental processes, in addition to photosynthesis, in cyanobacteria. These Gram-negative prokaryotes exhibit characteristic light-dependent developmental processes that maximize their fitness and resource utilization. The development occurring in response to radiance (photomorphogenesis) involves fine-tuning cellular physiology, morphology and metabolism. The best-studied example of cyanobacterial photomorphogenesis is chromatic acclimation (CA), which allows a selected number of cyanobacteria to tailor their light-harvesting antenna called phycobilisome (PBS). The tailoring of PBS under existing wavelengths and abundance of light gives an advantage to cyanobacteria over another photoautotroph. In this work, we will provide a comprehensive update on light-sensing, molecular signaling and signal cascades found in cyanobacteria. We also include recent developments made in other aspects of CA, such as mechanistic insights into changes in the size and shape of cells, filaments and carboxysomes. © 2023, Prof. H.S. Srivastava Foundation for Science and Society.
Sample Preparation and Visualization Protocol for Electron Microscopy–Based Analysis of Cyanobacteria
(CRC Press, 2024) Soumila Mondal; Bhaskar Sharma; Abhisek Majumdar; Sapna Tiwari; Pankaj K. Maurya; Anjali Gupta; Shailendra P. Singh; Prabhakar Singh
Electron microscopy (EM) is an effective imaging technique that has revolutionized our knowledge of cellular and subcellular biological structures. It enables the imaging of biological materials with nanometer-scale resolution, providing precise information on cellular morphology, organelle architecture, and cellular activities. In all areas of biology, including cell biology, microbiology, and molecular biology, EM has been used extensively to investigate the ultrastructural properties of biological materials. Electron microscopes use electrons (which have very short wavelengths) as the source of illuminating waves, resulting in high image resolution. To virtualize cellular and subcellular architecture, this resolution is necessary. Cyanobacteria lack apparent structural compartmentalization for cellular functions, necessitating the use of EM to decipher structural organization and interactions between different structures. Numerous ultrastructural details, such as the organization of thylakoids, cell walls, carboxysomes, and nucleoids, are required to comprehend physiological function and evolution (Lang 1968; Mareš et al. 2019). This technique can also disclose the cellular structure of nucleic acids (Rouquette et al. 2009; Ghosh et al. 2021). © 2024 selection and editorial matter, Shailendra P. Singh, Rajeshwar P. Sinha and Donat-P. Häder; individual chapters, the contributors.