BHU Repository :: Browsing by Author "Anupam Tiwari"

PublicationArticle

Accumulation of Secondary Metabolites and Improved Size of Glandular Trichomes in Artemisia annua

(Springer Science and Business Media B.V., 2020) Neha Pandey; Anupam Tiwari; Sanjay Kumar Rai; Shashi Pandey-Rai

Glandular trichomes are multicellular epidermal outgrowths that have characteristic globular head made up of secretory cells and store large quantities of specialized secondary metabolites. Artemisia annua is known for its medicinally important secondary metabolite “artemisinin” which is synthesized and stored in glandular trichomes. However, our understanding of morphological and transcriptional control related to glandular trichome development and accumulation of secondary metabolites in A. annua is available in scattered form. This chapter deals with the trichome biology including developmental and functional aspects along with their correlation with secondary metabolite accumulation in response to various biotic and abiotic signals of the environment using A. annua as model. This chapter also emphasizes the molecular mechanisms behind trichome development in A. annua and provides a glimpse of molecular players involved in this process. There are many environmental as well as intrinsic factors which directly or indirectly affect secondary metabolite synthesis and as a result determine the size of glandular trichomes. The compiled information available for A. annua trichome biology can further be utilized for exploring trichome engineering in many medicinal or aromatic plants which are less explored. © Springer Nature Switzerland AG 2020.

PublicationBook Chapter

Agronomic practices in faba beans

(Nova Science Publishers Inc., 2025) Anurag Tripathi; Anupam Tiwari; Akankhya Guru; Abhay Vikram Singh; Ashutosh Mishra; Amit Nagar

An important legume crop with both nutritional and environmental advantages, the faba bean (Vicia faba L.) is an essential part of sustainable farming systems. Although improving its yield and quality requires effective agronomic techniques, faba bean cultivation is complicated by problems such as soil nutrient constraints, disease risks, and fluctuating climate conditions. This study looks at how different agronomic techniques, such as crop rotation, tillage, sowing rates, irrigation, and fertilizer management, affect the crop's capacity to fix nitrogen, grow, and produce. Because of their nitrogen-fixing symbiosis, faba beans can increase soil fertility when included in various cropping systems, reducing the need for synthetic fertilizers. The results show that in order to maximize yields and increase resistance to environmental challenges, a balanced nutrient application, an adequate water supply, and an appropriate plant density are essential. By improving soil health and overall production in a variety of farming scenarios, optimizing these techniques promotes the sustainability of faba bean cultivation. This study emphasizes how crucial agronomic strategies are to attaining the best yields and promoting ecologically friendly faba bean farming. © 2025 Nova Science Publishers, Inc.

PublicationArticle

Biochemical and physiological characterization of a halotolerant Dunaliella salina isolated from hypersaline Sambhar Lake, India

(Blackwell Publishing Inc., 2019) Prabhakar Singh; Riyazat Khadim; Ankit K. Singh; Urmilesh Singh; Priyanka Maurya; Anupam Tiwari; Ravi K. Asthana

The objective of the present study was to characterize intrinsic physiological and biochemical properties of the wall-less unicellular cholorophyte Dunaliella salina isolated from a hypersaline Sambhar Lake. The strain grew optimally at 0.5 M NaCl and 16:8 h L:D photoperiod along with maintaining low level of intracellular Na + even at higher salinity, emphasizing special features of its cell membranes. It was observed that the cells experienced stress beyond 2 M NaCl as evidenced by increased intracellular reactive oxygen species and antioxidative enzymes, nevertheless proline and malondialdehyde content declined sharply accompanied by higher neutral lipid accumulation. Salinity exceeding 2 M resulted decrease in photosynthetic quantum yield (Fv/Fm) and enhanced glycerol synthesis accompanied by leakage. Super oxide dismutase seemed to play a pivotal role in antioxidative defense as eight isoforms were expressed differentially while catalase and glutathione peroxidase showing no significant change in their expression at higher salinity. The ability of D. salina to grow in range of salinities by sustaining healthy photosynthetic apparatus along with accumulation of valuable products made this alga an ideal organism that can be exploited as resource for biofuel and commercial products. © 2018 Phycological Society of America

PublicationArticle

Desiccation induced changes in osmolytes production and the antioxidative defence in the cyanobacterium Anabaena sp. PCC 7120

(Springer, 2013) Priyanka Singh; Anupam Tiwari; Sureshwar Prasad Singh; Ravi Kumar Asthana

Cells of Anabaena sp. PCC 7120, a low desiccation tolerant cyanobacterium, was subjected to prolonged desiccation and effect of loss of water was examined on production of osmolytes, and antioxidant response as well as on overall viability in terms of photosynthetic activity. During dehydration (22 h), the organism maintained about 98. 5 % loss of cellular water, yet cells remained viable as about 30 % of photosynthetic O2-evolution activity resumed upon hydrating (1 h) such cells. In desiccated state, cyanobacterial cells accumulated osmolytes within 1 h though their contents decreased thereafter. The highest levels of trehalose (179 nmol mg-1 protein), sucrose (805 nmol mg-1 protein) and proline (23. 2 nmol mg-1 protein) were attained within 1 h. Chlorophyll a and carotenoid contents also increased within 1 h but phycocyanin level showed opposite trend. The oxygen-evolving activity declined in desiccated cyanobacterial biomass while rehydration led to instant recovery, indicating that cells protect the photosynthetic machinery against desiccation. Notwithstanding, activities of antioxidant enzymes (catalase, peroxidase and superoxide dismutase) attained their peaks after 3 h of desiccation, though within 10 min of rehydration, their levels returned back close to basal activities of the cultured cells. We propose that onset of osmolyte production in conjunction with upshift of antioxidant enzymes apparently protects the cyanobacterial cells from desiccation stress. © 2012 Prof. H.S. Srivastava Foundation for Science and Society.

PublicationArticle

Mass cultivation of Dunaliella salina in a flat plate photobioreactor and its effective harvesting

(Elsevier Ltd, 2018) Sk Riyazat Khadim; Prabhakar Singh; Ankit Kumar Singh; Anupam Tiwari; Abhishek Mohanta; Ravi Kumar Asthana

Mass cultivation of Dunaliella salina was standardized in a flat plate photobioreactor followed by a vertical flat plate photobioreactor. Maximum biomass productivity (14.95 ± 0.43 mgL −1 d −1 dry cell weight) was achieved in the latter at inoculum concentration of OD 680nm = 0.1, 100 µmolm −2 s −1 light illumination and 1.0 L min −1 aeration. Semicontinuous operation with varying KNO 3 and NaHCO 3 concentrations resulted highest biomass productivity (17.85 ± 0.55 mgL −1 d −1 ) at 0.50 mM NaHCO 3 and 15 mM KNO 3 . However, maximum lipid (16.36 ± 1.18% dry cell weight) was achieved at 0.75 mM NaHCO 3 and 10 mM KNO 3 . Flocculation studies employing potash alum, FeCl 3 ·6H 2 O or pH showed harvesting efficiencies exceeding 90% in 0.75 mM potash alum or FeCl 3 ·6H 2 O or pH 11, but they yielded low concentration factor (<5) and were detrimental (Fv/Fm < 0.50). A combination of 0.50 mM FeCl 3 ·6H 2 O and pH 9 was found as most suitable flocculating strategy with maximum concentration factor (>14) and least damaging (Fv/Fm > 0.54). © 2018 Elsevier Ltd

PublicationReview

Molecular and epigenetic basis of heat stress responses and acclimatization in plants

(Springer, 2023) Anupam Tiwari; Shashi Pandey-Rai; Krishna Kumar Rai; Anjali Tiwari; Neha Pandey

Plants have developed highly sophisticated mechanisms to regulate stress responses. Plants change and reorient their transcriptome and proteome while dealing with the heat stress within minutes of being exposed to heat. The change in transcriptome/proteome is primarily driven by epigenetic modifications. The epigenetic modification also plays a huge role in acclimatizing the plants for heat stress and therefore, plays a significant role in faster and swift response in terms of expression of heat shock proteins and maintaining the structural and physiological stability. Epigenetic modifications such as DNA methylation and histone modifications like acetylation, phosphorylation, methylation play a central role in regulating transcription and translation. The present review will underline and discuss the role of different epigenetic modification in heat stress responses of plants and the acclimatization of plants to re-exposure to heat stress. Although the initial mechanism of plant’s responses to many abiotic stresses is similar, however, recent understanding has suggested heat-stress-specific epigenetic modifications in plants. The present review will also give a comprehensive detail of heat-stress-specific responses and underlying mechanisms in plants. © 2022, The Author(s) under exclusive licence to Archana Sharma Foundation of Calcutta.

PublicationArticle

Photo-induced biosynthesis of silver nanoparticles from aqueous extract of Dunaliella salina and their anticancer potential

(Elsevier B.V., 2017) Ankit Kumar Singh; Ratnakar Tiwari; Vijay Kumar; Prabhakar Singh; S.K. Riyazat Khadim; Anupam Tiwari; Vikas Srivastava; S.H. Hasan; R.K. Asthana

The synthesis of silver nanoparticles (AgNPs) via green route, using biological entities is an area of interest, because one of the potential applications in the nanomedicine. In the present study, we have developed photo-induced, ecofriendly, low cost method for biosynthesis of the stable silver nanoparticles using aqueous extract of Dunaliella salina (AED) which act as both reducing as well as stabilizing agent. Biosynthesis of the AgNPs was optimized as: sunlight exposure (30 min), AED (5% (v/v)) and AgNO3 (4 mM). Biosynthesis of AgNPs was monitored by using UV–Vis spectroscopy which exhibited sharp SPR band at 430 nm after 30 min of bright sunlight exposure. SEM and TEM analyses confirmed the presence of spherical AgNPs with average size of 15.26 nm. Crystalline nature of AgNPs was confirmed by SAED and XRD analyses where Braggs reflection pattern at (111), (200), (220) and (311) corresponded to face centered cubic crystal lattice of metallic silver. FTIR analysis revealed the involvement of various functional groups present in AED. AFM analysis confirmed the average surface roughness of synthesized AgNPs as 8.48 nm. AgNPs were also screened for anticancer potential using assay of calcein AM/PI, Annexin/PI and cancer biomarkers against cancer cell line (MCF-7), while normal cell line (MCF-10A) were kept as control. Interestingly, anticancer potential was comparable to the known anticancer drug (Cisplatin), and was not detrimental to the normal cell line. Therefore, such green synthesized AgNPs may be explored as anticancer agent. © 2016 Elsevier B.V.

PublicationArticle

Proline biosynthesizing enzymes (glutamate 5-kinase and pyrroline-5-carboxylate reductase) from a model cyanobacterium for desiccation tolerance

(2013) Priyanka Singh; Anupam Tiwari; Sureshwar Prasad Singh; Ravi Kumar Asthana

Drought is the most important abiotic stress, challenging sustainable agriculture globally. For desiccation being the multigenic trait, a combination of identified genes from the appropriate organism may render crop tolerant to the water stress. Among the compatible solutes, proline plays multifaceted role in counteracting such stress. The genes encoding proline biosynthesizing enzymes, glutamate 5-kinase (G5K), and pyrroline-5-carboxylate reductase (P5CR) from the low-desiccation-tolerant cyanobacterium Anabaena sp. PCC 7120, were cloned and overexpressed in Escherichia coli BL21(DE3) individually. The recombinant E. coli cells harboring G5K, failed to exhibit enhanced desiccation tolerance relative to those with P5CR that showed increased growth/survival over the wild type. This may be ascribed to the overexpression of the reductase gene. Multiple sequence alignment showed P5CR to be conserved in all the organisms. We hypothesize that P5CR gene from high-desiccation-tolerant cyanobacteria may be adopted as the candidate for making transgenic N2-fixing cyanobacterium for paddy fields and/or crop development in future. © 2013 Prof. H.S. Srivastava Foundation for Science and Society.

PublicationArticle

Role of Ca 2+ as protectant under heat stress by regulation of photosynthesis and membrane saturation in Anabaena PCC 7120

(Springer-Verlag Wien, 2019) Anupam Tiwari; Prabhakar Singh; Sk Riyazat Khadim; Ankit Kumar Singh; Urmilesh Singh; Priyanka Singh; Ravi Kumar Asthana

The present study was aimed at understanding the effects of heat stress on selected physiological and biochemical parameters of a model cyanobacterium, Anabaena PCC 7120 in addition to amelioration strategy using exogenous Ca 2+ . A comparison of the cells exposed to heat stress (0–24 h) in the presence or absence of Ca 2+ clearly showed reduction in colony-forming ability and increase in reactive oxygen species (ROS) leading to loss in the viability of cells of Ca 2+ -deficient cultures. There was higher level of saturation in membrane lipids of the cells supplemented with Ca 2+ along with higher accumulation of proline. Similarly, higher quantum yield (7.8-fold) in Ca 2+ -supplemented cultures indicated role of Ca 2+ in regulation of photosynthesis. Relative electron transport rate (rETR) decreased in both the sets with the difference in the rate of decrease (slow) in Ca 2+ -supplemented cultures. The Ca 2+ -supplemented sets also maintained high levels of open reaction centers of PS II in comparison to Ca 2+ -deprived cells. Increase in transcripts of both subunits ((rbcL and rbcS) of RubisCO from Ca 2+ -supplemented Anabaena cultures pointed out the role of Ca 2+ in sustenance of photosynthesis of cells via CO 2 fixation, thus, playing an important role in maintaining metabolic status of the heat-stressed cyanobacterium. © 2018, Springer-Verlag GmbH Austria, part of Springer Nature.

PublicationArticle

Role of calcium in the mitigation of heat stress in the cyanobacterium Anabaena PCC 7120

(Elsevier GmbH, 2016) Anupam Tiwari; Priyanka Singh; Ravi Kumar Asthana

The effects of exogenously added CaCl2 (0.25 mM) on photopigments, photosynthetic O2-evolution, antioxidative enzyme activity, membrane damage, expression of two heat shock genes (groEL and groES) and apoptotic features in Anabaena 7120 under heat stress (45 °C) for up to 24 h were investigated. Heat stress lowered the level of photopigments; however, Ca2+-supplemented cultures showed a low level reduction in Chl a but induced accumulation of carotenoids and phycocyanin under heat stress. Photosynthetic O2-evolving capacity was maintained at a higher level in cells from Ca2+-supplemented medium. Among the antioxidative enzymes, superoxide dismutase activity was unaffected by the presence or absence of Ca2+ in contrast to increases in catalase, ascorbate peroxidase and glutathione reductase activities in cells grown in Ca2+-supplemented medium. Lower levels of lipid peroxidation were recorded in Anabaena cells grown in Ca2+-supplemented medium in comparison to cells from Ca2+--deprived medium. Target cells grown in Ca2+-deprived medium developed apoptotic features in the early stages of heat shock, while Ca2+ application seemed to interfere with apoptosis because only a few cells showed such features after 24h of heat exposure, indicating a role for Ca2+ in maintaining cell viability under heat stress. There was also continuous up regulation of two important heat shock genes (groEL and groES) in Ca2+-supplemented cultures, exposed to heat shock, again indicating a role for Ca2+ in stress management. © 2016 Elsevier GmbH.

PublicationConference Paper

Synthesis and characterization of porous composite with tailored porosity fabricated using rice husk by utilizing red mud and coal mine tailing

(CRC Press/Balkema, 2025) Vaibhav Pandey; Ashish Singh Pareta; Anupam Tiwari; P. K. Singh; Ashutosh Gupta; Saroja Kanta Panda

Management and use of red mud (RM) and coal mine overburden waste (MW) have drawn attention over the past decade due to their enormous scale and associated environmental problems. The harmful impact of this solid waste and its leachates has damaged the nearby ecosystem and forced industries to look for alternative solutions just rather than dumping. Despite having a lot of research, industries are still looking for a solid solution that can be implemented. Mass conversion with economic feasibility is the major obstacle faced by these wastes. The current work examines the potential use of these wastes for fabricating porous ceramic bricks by incorporating multiple quantities of their mixture with rice husk. The physical qualities of bricks have been studied in relation to variations in the MW: RM ratio, sintering temperature, and Rice husk amount. The developed porous composite possesses apparent porosity, compressive strength, and thermal conductivity in the range of 26–54%, 0.83–6.83 MPa, and 0.37–0.67 W/mK respectively. The developed porous composite with tunable pore microstructure is seen as a potential material for thermal insulation and other similar applications. © 2025 The Author(s).