Browsing by Author "Anuradha Rai"

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A new insight into the commercial applications of halotolerant green algae Dunaliella
(Nova Science Publishers, Inc., 2018) Pradeep Kumar Rai; Anuradha Rai; Surendra Singh
Recently, the cultivation of microalgae as a renewable source of fuel and energy has been receiving much attention globally. Dunaliella is probably the most halotolerant and dominant photosynthetic eukaryote that thrives in most natural and artificial hypersaline niches occupied almost exclusively by halophilic archaebacteria. This alga is cultivated commercially as a source of many valuable macromolecules such as proteins, lipids and pigments. It is one of the best sources for the commercial production of carotene, glycerol and protein. Different species of Dunaliella have the ability to produce a wide variety of high-value bioactive compounds, fine biochemicals, and bulk compounds such as lipids, pigments, natural dyes and biomass. The ability to grow at high salt concentrations coupled with the production of high amount of β-carotene, glycerol and protein have made this microalga an attractive candidate for commercial application in medicine, the food industry and agriculture. © 2018 by Nova Science Publishers, Inc. All rights reserved.
Biodiversity and biogeography of microalgae with food and feed potential
(Elsevier, 2023) Anchal Singh; Anuradha Rai; Pradeep Kumar Rai; Naveen K. Sharma
Microalgae, including cyanobacteria, are a group of diverse microorganisms that exhibit oxygenic mode of photosynthesis as a common characteristic. Due to conceptual and technological/analytical limitations, their exact number is unknown and requires inputs from systematics, dispersal analyses, and biogeography. The group occupies all life-supporting habitats, which may be widely separated and present in disconnected geographies. They show both cosmopolitan and endemic distribution and are often subject to the technology used for their estimation. The precise mechanism of their dispersal is poorly understood. The use of molecular tools and resulting data has led to the refinement in the taxon boundaries and, thereupon, species delimitation, which is profoundly reshaping our understanding of their diversity, distribution, and difficulties associated with their accurate assessment. Furthermore, the sampling procedure for diversity estimation is yet to be standardized. The fluid nature of species characterization further complicates the task of enumeration of biodiversity indices. Statistical tools play a vital role in biodiversity estimation but are less used in studying microalgal diversity. Apart from highly acclaimed ecological roles, human use of microalgae for food, feed, medicine, fertilizers, and a slew of other uses is known since long (prior to 2700BCE). In recent times, attempts for using microalgae for nutraceuticals, biofuels, and therapeutic drug production have increased. In the present chapter, we have discussed the recent estimates of microalgal diversity, their biogeography, and the associated conceptual and technological constraints for their potential use as a food and feed source. © 2023 Elsevier Inc. All rights reserved.
Change in soil microbial biomass along a rural-urban gradient in Varanasi (U.P., India)
(UBM Exhibition Singapore PTE LTD, 2018) Pradeep Kumar Rai; Anuradha Rai; Surendra Singh
Soil microbial biomass has been used as an early indicator of change in soil properties resulting from urbanization. We analyzed the effect of urbanization along a rural–urban gradient on soil microbial biomass and physico-chemical properties of the soil. The mean microbial biomass carbon (MBC) value were 107.4, 121.3, and 134.2 μg g−1 of soil, respectively, for urban, sub-urban and rural sections of the gradient. Whereas, the mean microbial biomass nitrogen (MBN) was 10.2, 11.5, and 12.5 μg g−1 of soil for urban, sub-urban, and rural gradient. Similarly, the mean values of microbial biomass phosphorus (MBP) were 5.1, 5.8, and 6.3 μg g−1 of soil, for urban, sub-urban, and rural gradient, respectively. ANOVA and Tukey’s Honest Significant Difference (HSD) analyses showed significant difference (P ≤ 0.05) in microbial biomass with physico-chemical characteristics of soils. Maximal soil microbial biomass was reported for rural soils followed by sub-urban and urban soil. Disturbance in soil texture, increased in BD and decrease in soil moisture content as major factors responsible for depletion in soil microbial biomass in urban soils. Thus, suggesting that the urbanization adversely effected soil microbial biomass by altering natural soil characteristics. © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Changes in Water Soluble Protein Profile of Antarctic Cyanobacterium Nostoc Commune under Temperature Downshift from 25° to 5 °C
(Taylor and Francis Inc., 2019) Ranjana Tripathi; Pradeep Kumar Rai; Anuradha Rai; Surendra Singh
The cyanobacterium Nostoc commune (Nostocales) is an isolate from the Schirmacher Oasis Antarctica. The cyanobacterium is psychrotropic in nature; and maintained in laboratory at 25 °C temperature, in unialgal form. Here, we studied the change in protein profile of water soluble proteins from exponentially growing N. commune upon downshift from its optimum growth temperature (25 °C) to a low temperature (5 °C). Experimental set up used to analyze the proteome were- a sudden shift to low temperature (i.e., cold shock), after short- (8 days) and long-term acclimation (7 weeks) to low temperature (5 °C). Cold-shock resulted in an increase in Low molecular weight proteins (LMWPs) with clouding of diffused proteins. Further increase in the duration of incubation period (short- and long-term acclimation) caused dissociation of proteins, indicated by NaCl (50–600mM) induced dissociation of proteins. That is, high molecular weight proteins (HMWPs) dissociated into LMWPs resulting in an increased number of protein bands. This was further confirmed by addition of LMWPs (≤10KDa) resulting in re-association of proteins into HMWPs. Hence, we report that the cold-induced synthesis of LMWPs (≤10kDa) is a strategy adopted by the N. commune to survive at low temperature of Antarctica. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.
Characterization of phosphate solubilizing fluorescent pseudomonads from the rhizosphere of Aloe vera (L.)
(Taylor and Francis Ltd., 2018) Anuradha Rai; Pradeep Kumar Rai; Surendra Singh
Soil phosphorous (P) deficiency is a major constraint to plant production which is overcome by adding inorganic-phosphate as chemical fertilizers. Fluorescent pseudomonads are the diverse group of bacteria able to mobilize sparingly soluble phosphate form. Total three hundred seven fluorescent Pseudomonas isolates were obtained from the Aloe barbadensis (Miller) rhizosphere. These Pseudomonas strains were further evaluated in vitro for their ability to solubilize phosphate and to produce indole acetic acid (IAA), hydrogen cyanide (HCN), siderophore and 1-aminocyclopropane 1- carboxylate (ACC) deaminase. Fifty three (36.8%) isolates produced IAA and 52 (36.1%) isolates produced siderophores whereas 36 (25.0%) and 31 (21.5%) isolates produced HCN and ACC deaminase, respectively. A positive correlation existed between siderophore and ACC deaminase producers. Cluster analysis showed rhizosphere as the major factor influencing the ecological distribution and physiological characterization of phosphate solubilizing bacteria (PSB). Based on partial 16S rRNA gene sequencing PSB were identified as Pseudomonas putida, Pseudomonas sp. and Pseudomonas plecoglossicida with highest phosphate solubilization ability. In conclusion, these phosphate solubilizing fluorescent pseudomonads would help in understanding their role in phosphorus solubilization and identification of potent phosphorus solubilizers from the rhizosphere of commercially grown A. barbadensis. © 2017 Informa UK Limited, trading as Taylor & Francis Group.
Effect of fluorescent Pseudomonas on plant growth promotion of Aloe vera
(Taylor and Francis Ltd., 2024) Anuradha Rai; Vaibhav Kumar Singh; Naveen Kumar Sharma; Jay Shankar Singh; Vinod Kumar Singh; Brahma Swaroop Dwivedi; Pradeep Kumar Rai
Modern agriculture practices heavily depend on the application of chemical fertilizers and continuous application disturbs the soil quality and health. Fluorescent Pseudomonas are the well characterized group of bacteria proficient in plant growth promotion and have excellent phosphate solubilizing abilities and solubilize insoluble phosphate to plants available form via secretion of organic acids. This study focused on the phosphate solubilization ability of Pseudomonas, arouse of Aloin-A molecule, gluconic acid production, as well as biometric parameters of key medicinal plant, the Aloe vera (Aloe barbadensis). Two strains (P. putida and Pseudomonas sp.) were found very effective PSBs and solubilized 236.73 and 153.73 mg L−1 phosphate, respectively. High-performance liquid chromatography analysis (HPLC) showed the production of gluconic acid (GA). P. putida and P. sp. produced 23970 ± 231 and 21538 ± 129 mg L−1 GA, respectively. Inoculation of the plants with consortium of P. putida and Pseudomonas sp. enhanced the plant growth, soil available P and phosphate uptake in plants than individual inoculation. An increase in aloin-A content (18.15 and 28.71 fold) was recorded in A. barbadensis treated with a PSB consortium in a soil amended without and with TCP (tricalcium phosphate), respectively. P-uptake ultimately enhances the aloin-A synthesis and biomass of plant. Therefore, agronomic attributes of Aloe vera plants can be improved for used as a medicinal plant through application of potent Fluorescent Pseudomonas. © 2023 Taylor & Francis Group, LLC.
Exploiting beneficial traits of plant-associated fluorescent pseudomonads for plant health
(Springer International Publishing, 2017) Anuradha Rai; Pradeep Kumar Rai; Surendra Singh
Plants have recently been recognized as meta-organisms harboring distinct microbiome and reveling close symbiotic relationship with the associated microflora. Each plant has a unique niche and possesses species-specific microbes to a certain proportion and majority of the ubiquitous microbes that fulfill important host as well as ecosystem function. Currently, agricultural crops are facing challenges due to imbalance of micronutrients, deterioration of soil health, fluctuating environmental conditions, and increasing pest and pathogen attack. The rhizosphere region of the plants is the most extensively studied area due to its remarkable microbial diversity. Fluorescent pseudomonads are Gram-negative, motile, rod-shaped bacteria predominantly inhabiting the vicinity of rhizosphere and sometimes even the root interior. They effectively colonize the plant roots and rhizosphere soil because of their excellent ability to utilize a variety of organic substrates exuded by the plant roots. The study on the role of fluorescent pseudomonads in agriculture has been a matter of great interest attributable to their ability to control plant diseases, maintain soil health, and influence the plant growth directly or indirectly. They directly promote the plant growth by producing secondary metabolites such as siderophores and phosphatases that can chelate iron and solubilize phosphorus, respectively, from the soil and make them available to the plants. They also produce indole-3-acetic acid (IAA) and 1-aminocyclopropane-1-carboxylate (ACC) deaminase that sequesters ACC, the precursor of ethylene. They also indirectly promote the plant growth mainly by suppressing the plant pathogens by producing an array of antibiotics and fungal cell wall degrading enzymes. Specific metabolites produced by fluorescent pseudomonads may elicit defense reactions and induce systemic resistance of the host plants. Introduction of such multifunctional rhizobacteria to the plant roots can lead to increased plant growth and protection against phytopathogens. This chapter reviews the beneficial traits of the fluorescent pseudomonads and their relationship to the functioning in the rhizosphere. © 2017 Springer International Publishing AG.
Poly-β-hydroxybutyrate production by the cyanobacterium scytonema geitleri bharadwaja under varying environmental conditions
(MDPI AG, 2019) Manoj K. Singh; Pradeep K. Rai; Anuradha Rai; Surendra Singh; Jay Shankar Singh
The production of poly-β-hydroxybutyrate (PHB) under varying environmental conditions (pH, temperature and carbon sources) was examined in the cyanobacterium Scytonema geitleri Bharadwaja isolated from the roof-top of a building. The S. geitleri produced PHB and the production of PHB was linear with the growth of cyanobacterium. The maximum PHB production (7.12% of dry cell weight) was recorded when the cells of S. geitleri were at their stationary growth phase. The production of PHB was optimum at pH 8.5 and 30 °C, and acetate (30 mM) was the preferred carbon source. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
Study of Phosphate Solubilizing Fluorescent Pseudomonas Recovered from Rhizosphere and Endorhizosphere of Aloe barbadensis (L.)
(Taylor and Francis Ltd., 2023) Anuradha Rai; Naveen Kumar Sharma; Vinod Kumar Singh; Brahma Swaroop Dwivedi; Jay Shankar Singh; Pradeep Kumar Rai
Phosphorus (P) is a key nutrient required by plants for their growth and development. A large part of applied phosphatic fertilizer becomes unavailable due to its fixation in soil. In rhizosphere, fluorescent Pseudomonads are instrumental in phosphate solubilization. We isolated Pseudomonads from the rhizosphere of Aloe barbadensis (L.), and screened them for their plant growth promoting ability such as - solubilization of phosphate, auxin production and 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. A total of 307 fluorescent Pseudomonas were isolated and screened, of which, 24 isolates showed a strong phosphate solubilizing ability, ranging from 69.71 to 236.73 µg ml−1. The Indole acetic acid (IAA) production by all 24 isolates varied from 28.44 to 151.99 µg ml−1. However, 17 isolates produced ACC-deaminase ranging from 8.19 to 10.27 µmol mg−1 h−1. Analyses of 16S rRNA gene and Pseudomonas-specific genes grouped the isolates in seven different species of fluorescent Pseudomonas. Genotypic analysis based on 16S rDNA-RFLP using restriction enzymes (HaeIII, AluI and MspI) and BOX-PCR generated unique genotype specific pattern. The results suggested that Pseudomonas diversity has no association with microenvironments and the sampling site of the plants. 16S rRNA gene-based diversity indices revealed great diversity among the fluorescent Pseudomonas recovered from the rhizospheric regions of the Aloe. Due to the above plant growth-promoting traits, fluorescent Pseudomonas can be exploited as bio-inoculants for crops, with minimal damage to the environment. © 2023 Informa UK Limited, trading as Taylor & Francis Group.
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.
Urbanization reduces overall cyanobacterial abundance but favors heterocystous forms
(Elsevier B.V., 2021) Pradeep Kumar Rai; Anuradha Rai; Naveen Kumar Sharma; Vinod Kumar Singh; Surendra Singh
Managing agricultural land, both in terms of quantity and quality, is one of the major challenges of the world. Urbanization is a powerful human-induced land use transformation that not only affects adversely the availability of arable lands, but also the soil microbial diversity crucial for maintaining fertility and other soil functions. The study reports the change in cyanobacterial diversity and community composition along a rural-urban gradient, through amplicon sequencing using Illumina MiSeq approach. Urbanization significantly altered the diversity, abundance and community composition of cyanobacteria that vary along the gradient. Rural soils had the highest diversity and maximal abundance of uncultured cyanobacteria, followed by sub-urban and urban soils. In general, along the gradient Oscillatoriales (non-heterocystous forms) were the most abundant taxa, while abundance of Nostocales (i.e., heterocyst bearing N2-fixers) increased in the urban soil. The favored growth of specific taxa in urban soils indicates biotic homogenization. The relative dominance of genus Leptolyngbya in urban and sub-urban soils could be used as an indicator of urbanization. © 2021 Elsevier B.V.
Use of biowaste to ameliorate chromium-contaminated soils to improve crop productivity
(Elsevier B.V., 2024) Anuradha Rai; Naveen Kumar Sharma; Vinod Kumar Singh; Ashish Rai; Vipin Kumar; Abhinav Kumar; Jay Shankar Singh; Sanjay Kudesia; Pradeep Kumar Rai
Increasing discharge of untreated industrial effluents has led to high metal loads in different environments. In the recent past Chromium (Cr) has emerged as a severe pollution to soil and aquatic ecosystems. Its global average load in soil is 54 ppm. Chromium has deleterious effects on crops and the subsequent food chain. If ingested, hexavalent chromium [Cr (VI)] is highly carcinogenic to faunal health. Here, we investigate the use of biowaste on chromium-contaminated soils to promote phytostabilization and overall improvement in crop productivity via decreased solubilization, restricted leaching, higher bioavailability of micronutrients, along with the efficient recycling of waste from the environment. Biowaste amendments facilitate complex processes such as stable compound formation after reacting to organic ligands, precipitation on surfaces, and ion exchange phenomenon; to improve fertility, physical health, and microbial activity in soil. The resulting improved soil quality promotes resettlement of vegetation and better plant growth and development. The potency of different biowastes to immobilize the hazardous metal(loid)s depends on their chemical nature, the extent of their degradation by microbes, their reaction in specific soil-type and concerned metal(loid)s. We need to develop different bio-remedial strategies to curtail the Cr-phytotoxicity, and ensure sustainable crop productivity. © 2024 The Authors