Browsing by Author "K.D. Pandey"

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Biochemical and molecular identification of Solanum lycopersicum L. temperature tolerant bacterial endophytes
(Elsevier Ltd, 2019) Monika Singh; Ajay Kumar; K.D. Pandey
Endophytes are non-pathogenic microorganisms and potential natural bio-inoculant that reside within internal tissues of plant, without causing any apparent symptoms of infection and improve the plant health through acquisition of nutrients. The endophytic bacteria were isolated from the roots of Solanum lycopersicum L. surviving at 45–47 °C in the month of June 2013. On the basis of morphological, biochemical, carbon utilization pattern by Biolog and 16S rRNA gene sequence analysis, the isolates were identified as Rhizobium pusense (MS-1), Bacillus flexus (MS-2), B. cereus (MS-3), Methylophilus flavus (MS-4) and Pseudomonas aeruginosa (MS-5). Most of the endophytic bacterial strains showed plant growth promoting traits activities such as phosphate solubilization, production of IAA, siderophore, ammonia, and nitrate reductase. Carbon sources and other chemicals utilization pattern observed with GEN III microplate of Biolog exhibited strains specific responses. Ten antibiotics discs and 96 wells PM 11C plates were used for their antibiotic sensitivity assay. All the strains were sensitive to chloramphenical, erythromycin, rifampicin, piperacillin, imipenam and gentamycin, while P. aeruginosa (MS-5) was resistant to penicillin, linezolid, and clotrimazole discs. This is first report of M. flavus, a facultative methylotroph as an endophyte of tomato plant. © 2019
Biosynthesis of nanoparticles and applications in agriculture
(Elsevier, 2019) Monika Singh; Meenakshi Srivastava; Ajay Kumar; K.D. Pandey
Physical, chemical, and biological methods have been used to synthesize various types of nanoparticles. In the last few decades, different types of metallic nanoparticles including gold, silver, copper, tellurium, titanium, selenium, platinum, and palladium have been synthesized from plants and microbes including bacteria, actinomycetes, fungi, and cynobacteria. However, despite the stability, the rate of biological nanoparticle synthesis by other methods is slower than microbial synthesis. Today many metallic nanoparticles and their oxides are being considered for direct applications in soils to enter plants to reduce the use of chemical fertilizers and pesticides and to increase the yields of crops. © 2019 Elsevier Inc. All rights reserved.
Cyanobacteria as a Biocontrol Agent
(Springer International Publishing, 2022) Priya Yadav; Rahul Prasad Singh; Arun Kumar Patel; K.D. Pandey; Rajan Kumar Gupta
Cyanobacteria, one of the least investigated microbes, may synthesize and generate a significant number of antimicribial secondary metabolites. As they are ubiquitous in distribution and present in all possible habitats, cyanobacteria have developed several mechanisms to survive in various extreme habitats. Also, they are compatible biocatalysts, and they can be used in the field of “white biotechnology” for increasing the sustainable manufacture of nutraceutical and pharmaceutical compounds as novel drugs and also as clean energy sources such as biodiesel and hydrogen. Cyanobacteria are known as a mother of wide categories of secondary metabolites with different biological activities, i.e., antibacterial, antitumoral, antiviral, antifungal, antialgal, antimalarial, antiinflammatory, and anticancer properties. In this chapter, we try to uncover the application of various metabolites like phytols, free fatty acids, exopolysaccharides, phenolics, terpenoids, phytoene, sterols, carotenoids, MAAs, scytonemin, phytohormones, cyanotoxins, biocides (algicides, fungicides, bactericides, and insecticides), etc. and its various applications. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.
Cyanobacteria in Antarctica: ecology, physiology and cold adaptation.
(2004) K.D. Pandey; S.P. Shukla; P.N. Shukla; D.D. Giri; J.S. Singh; P. Singh; A.K. Kashyap
Cyanobacterial species composition of fresh water and terrestrial ecosystems and chemical environment of water in Schirmacher Oasis in Continental Antarctica was investigated. Over 35 species of cyanobacteria were recorded. Diazotrophic species both heterocystous and unicellular contributed more than half to the count except in lake ecosystem. The species composition varied among the fresh water as well as terrestrial ecosystems. The physico-chemical analyses of water revealed its poor nurient content which might have supported the growth of diazotrophic cyanobacteria in an Antarctic environment. Among the cyanobacteria Oscillatoria, Phormidium and Nostoc commune were the dominant flora in most of the habitats. The physiological characteristics of isolated cyanobacteria strains indicated that N2-fixation, nitrate uptake, nitrate-reduction, ammonium-uptake, GS-transferase activity and photosynthesis was unaffected at low temperature (5 degrees C) which indicated low temperature adaptation for Antarctic cyanobacteria. This phenomenon was not evident in different strains of tropical origin. The temperature optima for N2-fixation for the different Antarctic cyanobacterial strains was in the range of 15-25 degrees C, nearly 10 degrees C lower than their respective reference strains of tropical origin. Similar results were obtained for cyanobacteria-moss association. The low endergonic activation energy exhibited by the above metabolic activities supported the view that cyanobacteria were adapted to Antarctic ecosystem.
Differential sensitivity of three cyanobacteria to the rice field herbicide Machete
(1986) K.D. Pandey; A.K. Kashyap
The effect of the rice field herbicide Machete (2‐chloro‐2′6′‐diethyl‐N‐(Butoxymethyl)acetanilide) on the growth and cell composition of Anacystis nidulans, Nostoc muscorum and Anabaena doliolum was investigated. Growth of these cyanobacteria was completely inhibited at 2.5, 5.0 and 20 μg/ml, respectively, while a slight stimulation of growth was observed at lower concentrations. Stimulation of cyanobacterial growth in the presence of low concentrations of Machete was associated with an increase in the cellular levels of phycobilins and RNA while there was little impact on the levels of chlorophyll a and DNA. Photosynthetic pigments were degraded at lethal concentrations. The toxicity of the herbicide towards N. muscorum and A. doliolum could be reversed by supplementing the growth medium with either nitrate, nitrite or ammonia. This did not apply for A. nidulans. It is suggested that Machete inhibited nitrogen fixation in the former two strains while availability of nutrients was affected in the latter strain. In either case death of the organisms was most likely due to nitrogen starvation. Copyright © 1986 Wiley‐VCH
Effect of modulated microwave frequencies on the physiology of a cyanobacterium, Anabaena doliolum
(1999) Subash Rai; S.P. Singh; Samarketu; S.P. Tiwari; A.K. Mishra; K.D. Pandey; A.K. Rai
The effect of microwave modulated with square waves of different pulse repetition frequencies was studied on the physiologic behavior of the cyanobacterium Anabaena doliolum. The organism was exposed either directly after inoculating the nutrient solution or indirectly by exposing the nutrient solution before inoculation with the cyanobacterium cells for 1 h to microwave (9.575 GHz) modulated with square wave pulse repetition frequencies of 1000, 700, 500, 200, 100, and 50 Hz at a fixed incident power density (0.658 mW/cm2). This study reveals that microwaves athermally induce different biologic effects, perhaps by changing the structures of water. Modulation frequency-dependent water structures appear to cause the biologic effects by differentially partitioning the ions, altering the rate and/or directions of biochemical reactions, or other mechanisms.
Effect of modulated microwave frequencies on the physiology of a cyanobacterium, Anabaena doliolum
(Marcel Dekker Inc., 1999) Subash Rai; S.P. Singh; Samarketu; S.P. Tiwari; A.K. Mishra; K.D. Pandey; A.K. Rai
The effect of microwave modulated with square waves of different pulse repetition frequencies was studied on the physiologic behavior of the cyanobacterium Anabaena doliolum. The organism was exposed either directly after inoculating the nutrient solution or indirectly by exposing the nutrient solution before inoculation with the cyanobacterium cells for 1 h to microwave (9.575 GHz) modulated with square wave pulse repetition frequencies of 1000, 700, 500, 200, 100, and 50 Hz at a fixed incident power density (0.658 mW/cm2). This study reveals that microwaves athermally induce different biologic effects, perhaps by changing the structures of water. Modulation frequency-dependent water structures appear to cause the biologic effects by differentially partitioning the ions, altering the rate and/or directions of biochemical reactions, or other mechanisms.
Endophytic bacteria in plant disease management
(Elsevier, 2019) Monika Singh; Meenakshi Srivastava; Ajay Kumar; A.K. Singh; K.D. Pandey
Agricultural activities are increasingly occupying a prominent place since the advent of chemical fertilizers, synthetic growth regulators, and pesticides to meet the needs of ever-increasing population. Application of synthetic and chemical substances to check the spread of phytopathogens in the crop fields is not appreciable in any cost. Thus, the elimination of huge application of agrochemicals through deployment of biological agents would improve the agricultural practices in a sustainable manner. Plant growth-promoting microorganisms (PGPMs), particularly endophytes play a major role in controlling such problems and unlike chemical agents, work well without losing the core benefits as imparted by the chemical and synthetic agents. Endophytes associate with compatible host plants and provide benefit to them through various production of phytohormones, supplementation of nutrients, and suppression of pathogen access to host system and thus improving plant growth and yield. The biotechnological and industrial potential of these microbes could be better estimated by analyzing their modes and constraints with host plant interaction. The net consequences of plant growth-promoting rhizobacteria (PGPR) and endophytes activities are growth stimulation of plants. This chapter deals with the importance of endophytic bacteria, and their role as biocontrolling agents for disease management of important crop plants. © 2020 Elsevier Inc. All rights reserved.
Enhanced hydrogen photoproduction by non-heterocystous cyanobacterium Plectonema boryanum
(Elsevier Ltd, 1996) A.K. Kashyap; K.D. Pandey; S. Sarkar
Nitrogenase activity was derepressed in Plectonema boryanum following 18-24 h of microaerobic incubation. The cyanobacterium evolved hydrogen at a slow rate. Addition of reducing substances (sulfide, sulfite or dithionite) to the diazotrophic cultures resulted in an increase in nitrogenase activity or photoproduction of hydrogen. The reducing substances also restored phycocyanin degradation.
Enhanced hydrogen production by coupled system of Halobacterium halobium and chloroplast after entrapment within reverse micelles
(Elsevier Science Ltd, 1999) A. Singh; K.D. Pandey; R.S. Dubey
Reverse micelles were used for the enhanced rate of photoproduction of hydrogen using the coupled system of Halobacterium halobium and chloroplasts organelles. Different combinations of organic solvents and surfactants were used for generating reverse micelles. A several fold enhancement in the rate of H2 production was observed when the coupled system was entrapped within reverse micelles as compared to the aqueous suspension where no detectable H2 was produced. The coupled system immobilized in reverse micelles formed by sodium lauryl sulfate and carbontetrachloride yielded maximum rate of H2 evolution. The optimum temperature for such hydrogen production was 40 °C using light of 520-570 nm wavelength and 100 lux intensity.
Environmental determinants of soil methane oxidation and methanotrophs
(2013) Prabhu Nath Shukla; K.D. Pandey; Virendra Kumar Mishra
Methane (CH4) is one of the strongest greenhouse gases. Sources of CH4 are anthropogenic and natural, former playing ∼60% role. Major sink for CH4 are the atmospheric OH and Cl radicals (originating from CFCs), and biological system. Biological CH4 sink is mediated through the CH4 oxidation by the specialized group of bacteria called methanotrophs (MB). Methanotrophs have been reported from almost all the soil systems such as sediments, oceans, extremes of pH, salinity, and temperature. They oxidize methane aerobically in the presence of the enzyme methane monooxygenase (MMO). Anaerobic methane oxidation (AOM) also occurs in marine ecosystem where sulfate is final electron acceptor. Methanotrophs are of two types, first is cultured and low affinity group while the second is uncultured and high affinity group. Most of them can be grouped as Type I and Type II belonging to γ-and α-Proteobacteria, respectively. They may constitute up to 2% of total bacterial population in soil depending on physical factors such as water, temperature, soil depth, pH, texture, gaseous atmosphere (methane, oxygen, and CO2), soil organic content, and biological factors such as vegetation and microbial consortia. Besides, anthropogenic factors such as fertilizers, agro-and organochemicals, and land use pattern have strong influence over them. Global climate change including acid rain, high temperature, increasing rainfall, and drought have potential to affect the global methane sink activity. The authors attempt to review the recent advances made regarding CH4 oxidation and methanotrophic population size as well as community structure as affected by the various natural and anthropogenic factors. © 2013 Taylor and Francis Group, LLC.
Factors Affecting Formation of Spores (Akinetes) in Cyanobacterium Anabaena doliolum (AdS strain)
(1987) K.D. Pandey; A.K. Kashyap
The effect of various physical and chemical factors on spore formation of Anabaena doliolum [AdS strain*)] was investigated under laboratory conditions. Among the three inorganic nitrogen sources, nitrate and nitrite (0.5 mM) were slightly stimulatory to sporulation, however, the specific growth rate was reduced in comparison to N-free grown culture. Ammonium (all concentrations) was inhibitory to growth as well as to sporulation. Dilution of phosphate in the medium was stimulatory whereas dilution of the medium was inhibitory to sporulation. Temporal relationship between spore differentiation, depletion of phosphate from the medium, and development of alkaline phosphatase activity suggest that induction of this enzyme may be considered as one of the important events preceeding sporulation. Metabolic inhibitors like sodium azide, sodium fluoride, and sodium arsenate were stimulatory either in terms of the time required for sporulation or the spore frequency. Growth rate as well as sporulation of A. doliolum was more enhanced at 32 ±2 °C than at 25 ±1 °C. Increasing light intensities (from 500lx to 3,000lx) increased the sporulation frequency with a gradual decrease in the time required for spore initiation. pH 8.0 of the medium was most suitable for sporulation. © 1987, Gustav Fischer Verlag, Stuttgart. All rights reserved.
Factors modulating differentiation of spores: Characterization of mutants defective in sporulation in the cyanobacterium Anabaena doliolum (AdS strain)
(Springer-Verlag, 1986) K.D. Pandey; A.K. Kashyap
Mutants of Anabaena doliolum (AdS strain) altered with respect to the time of initiation and degree of sporulation were isolated following mutagenesis with N-methyl-N′-nitro-N-nitrosoguanidine and hydroxylamine. The non-sporulating mutant showed a high phycocyanin (Pc): chlorophyll a (chl a) ratio (ca. 7.2) as compared to sporulating strains (Pc:chl a, 4.7-5.3). Also this strain seemed to have higher RNA pools per unit of genomic material as reflected in a higher RNA:DNA ratio. The data suggest that degradaton of phycocyanin and controlled RNA synthesis are prerequisites for sporulation. Mutants exhibiting non-sporulation and delayed initiation of sporulation accumulated more nitrogen through nitrogen fixation, probably indicating nitrogenase function over an extended vegetative phase. © 1986 Springer-Verlag.
Growth Characteristics and Life Cycle of Myosarcina sp. under Culture Conditions
(1986) A.K. Kashyap; K.D. Pandey
Myxosarciii,a sp. was isolated from local soils and its life cycle and nutritional behaviour were investigated. The cyanobacterium grew in modified Chu-10 medium with a generation time of about 48 h. The optimal pH for growth was 8.6. Out of eight combined nitrogen sources tested, sodium nitrite (5 X 10-3 M) and potassium nitrate (5 X 10-3 M) proved to be ideal nitrogen sources while dipotassium hydrogen phosphate at a concentration of 7.5 X 10-5 M was best for growth. The freshl-- liberated baeocytes (endospores) were 5-6 Itm in diameter and enlarged up to 10-12 Icm before successive divisions in alternating planes ensured. The mature colonies showed cubical symmetry and the most probably number of baeocytes liberated per vegetative cell ranged between 4-8. © 1986, All rights reserved.
Hydrogen photoproduction by filamentous non-heterocystous cyanobacterium Plectonema boryanum and simultaneous release of ammonia
(1992) Sukla Sarkar; K.D. Pandey; A.K. Kashyap
Plectonema boryanum (filamentous, non-heterocystous cyanobacterium) photoproduced H2 when cells grown aerobically in nitrate were transferred to microaerobic or anaerobic conditions without nitrate. It was observed that H2 photoproducing cells simultaneously excreted ammonium in the medium, which was possibly due to phycocyanin degradation [decrease in chlorophyll a (Chl a):phycocyanin ratio in comparison to aerobic nitrate-grown cells]. Although nitrogenase (measured as H2 evolution) was induced in Ar:CO2 (96:4 v/v), inclusion of N2 in the gas phase (Ar:CO2:N2, 72:4:24 v/v) resulted in a 2-fold increase in H2 evolution. Addition of l-methionine DL-sulphoximine (MSX, glutamine-synthetase inhibitor), besides stimulating ammonium excretion in the medium, resulted in a 4.5-fold increment of H2 photoproduction (1.43 μmol H2 mg-1 dry wt h-1) in comparison to cells in Ar:CO2 gas phase (0.31 μmol H2 mg-1 dry wt h-1). Inhibition of photosystem II by 3(3,4-dichlorophenyl)1,1-dimethyl urea (DCMU) caused an increment of 1.6 and 3.2-fold in Ar:CO2 and Ar:CO2:N2, respectively, in comparison to cells incubated in Ar:CO2 gas phase alone. Simultaneous production of H2 and NH4+ was at a maximum when MSX and DCMU were added together in suboptical concentrations. Immobilization of cells in calcium alginate prolonged the duration (12 days) of H2 evolution and NH4- excretion. © 1992.
Hydrogen production by Rhodopseudomonas at the expense of vegetable starch, sugarcane juice and whey
(1994) S.P. Singh; S.C. Srivastava; K.D. Pandey
Four local strains of Rhodopseudomonas sp. (BHU strains 1-4) evolved hydrogen at the expense of potato starch, sugarcane juice and whey (1% in each case) in the presence of light (2 klux), under anaerobic conditions (argon/CO2, 95/5, v/v). Among the three substrates, sugarcane juice supported the maximum level of H2 production, followed by potato starch and whey at the rates of 45, 30 and 25 μl H2 h-1 mg-1 bacterial cell dry weight, respectively. Although elevated temperature (45°C) suppressed H2 evolution by strains 1, 2 and 3, the thermotolerant strain (BHU strain 4) has shown encouraging results. Alginate-immobilized cells under an identical experimental regime, exhibited an almost one-and-a-half times improvement in H2 production in the cases of all the above substrates over their free cell counterpart. Preliminary experiments have shown the presence of amylase in all the bacterial strains and work is in progress to characterize this enzyme so that the system could be used for efficient consumption of starch-based agro- products. © 1994.
Impact of pesticides applications on the growth and function of cyanobacteria
(Elsevier, 2020) Vipin Kumar Singh; Sandeep Kumar Singh; Prashant Kumar Singh; Hariom Verma; K.D. Pandey; P.K. Singh; Ajay Kumar
Recently from last few decades, indiscriminate use of chemical pesticides not only affects the texture and productivity of soil but also affects the environment, health-related issues, and the nontarget microorganism. In the paddy field ecosystem, cyanobacteria are the integral part, which actively involved in maintaining nutrient availability, soil fertility, yield enhancement via biological nitrogen fixation, mineralizing activity, etc. But the continuous and higher dose application of pesticides (either insecticides or herbicides) in the paddy fields leads to a toxic or inhibitory impact on the growth and physiology of native cyanobacterial species. In general, lower concentrations of insecticides or herbicides have a stimulatory effect on the various cyanobacterial species and enhance the growth, nitrogen fixation activity, photosynthetic pigments, whereas higher doses lead to even death of the microorganisms. Therefore in this chapter, we tried to summarize the ecotoxicological impact of pesticides on the growth and function of native cyanobacterial species in the paddy field ecosystem. © 2020 Elsevier Inc. All rights reserved.
Induction of mutation in the cyanobacterium Anabaena doliolum: A strain-specific property
(1992) K.D. Pandey; A.K. Kashyap
Mutations with respect to the sporulating character in the cyanobacterium Anabaena doliolum (AdS and AdB strains) were induced after treatment with acriflavin, acridine organge 9-aminoacridine, N-methyl-N′-nitro-N-nitrosoguanidine, ethyl methanesulfonate, hydroxylamine, nitrous acid, low pH (pH 4.2) and elevated temperature (65±1 °C). Exposure to higher temperature was most effective in inducing nonsporulating mutants in both strains. Uptake of acridine dyes, inactivation and mutability with respect to sporulation of two strains of cyanobacterium A. doliolum revealed that the mutagen uptake could be directly correlated with the frequency of induced mutations but that survival and mutability are independent strain-specific properties. © 1992, Folia Microbiologica. All rights reserved.
Influence of NaCl on photosynthesis and nitrogen metabolism of cyanobacterium Nostoc calcicola
(Maik Nauka Publishing / Springer SBM, 2015) V. Singh; K.D. Pandey; S. Mesapogu; D.V. Singh
Nostoc calcicola, a halotolerant alkaliphilic, nitrogen-fixing cyanobacterium, was grown under various NaCl concentrations (from 500 to 2000 mM) at alkaline pH. In cyanobacteria, physiological and biochemical responses were correlated with the external salt stress. The optimal condition for cell growth of N. calcicola isolated from alkaline ‘Usar’ soils of northern India was 500 mM NaCl at pH 10.5, accompanied with an increase in photosynthetic O2 evolution, carbohydrate content and activities of nitrate reductase, glutamine synthetase, photosystem I and photosystem II. Under salt stress conditions above 500 mM NaCl, cell growth and carbohydrate contents reduced. The results indicate that production of carbohydrates under salinity stress at alkaline pH acts as major mechanism of salt tolerance in cyanobacteria. © 2015, Pleiades Publishing, Inc.
Interaction of turmeric (Curcuma longa L.) with beneficial microbes: a review
(Springer Verlag, 2017) Ajay Kumar; Amit Kishore Singh; Manish Singh Kaushik; Surabhi Kirti Mishra; Pratima Raj; P.K. Singh; K.D. Pandey
Curcuma longa L., commonly known as turmeric, is a rhizomatous herb of the family Zingiberaceae. It is mostly used as a spice, a coloring agent and broadly used in traditional medicine such as Ayurveda, Unani, etc., Turmeric rhizomes interact with a large numbers of rhizosphere-associated microbial species, and some enter the plant tissue and act as endophytes. Both rhizospheric and endophytic species are directly or indirectly involved in growth promotion and disease management in plants and also play an important role in the modulation of morphological growth, secondary metabolite production, curcumin content, antioxidant properties, etc. The present review focuses on the rhizobacterial and endophytic bacterial and fungal populations associated with the turmeric. © 2017, Springer-Verlag GmbH Germany.