Browsing by Author "A.K. Mishra"

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Action of 2,4-dichlorophenoxyacetic acid and rifampicin on heterocyst differentiation in the blue-green alga, Nostoc linckia
(Springer India, 1981) D.N. Tiwari; A.K. Pandey; A.K. Mishra
2,4-Dichlorophenoxyacetic acid, a commonly used herbicide, increased the growth of the filamentous blue-green alga, Nostoc linckia at doses upto 100 μg /ml. The herbicidetreated N2-cultures showed enhanced heterocyst frequency and N2-growth. Thus, the herbicide stimulated algal growth at the expense of molecular nitrogen under aerobic growth conditions. Rifampicin caused chain formation of heterocysts. This was effectively counteracted by 2,4-dichlorophenoxyacetic acid, suggesting a biological interaction between them at the level of the heterocyst spacing control mechanism. © 1981 Indian Academy of Sciences.
An evaluation of the toxicity of the oils of Cymbopogon citratus and Citrus medica in rats
(1992) A.K. Mishra; N. Kishore; N.K. Dubey; J.P.N. Chansouria
In the present study the effect of chronic ingestion of a diet treated with different concentrations of essential oils of Cymbopogon citratus and Citrus medica on body weight, diet consumption, haemoglobin, total and differential leucocyte count, blood glucose, protein, cholesterol and urea levels and glutamic oxalacetic transaminase, glutamic pyruvic transaminase and alkaline phosphatase activity has been investigated in albino rats. Rats in the treated groups showed a more pronounced increase in body weight in comparison to control rats after 60 days. The rats of the treated group consumed more diet than those of the control group. The haemoglobin percentage, total and differential leucocyte count, blood glucose, protein, cholesterol, urea, SGOT, SGPT and alkaline phosphatase did not differ significantly between the rats of control and treated groups. Copyright © 1992 John Wiley & Sons, Ltd.
Assessment of quorum sensing effects of tyrosol on fermentative performance by chief ethnic fermentative yeasts from northeast India
(John Wiley and Sons Inc, 2021) B.J. Nath; A.K. Mishra; H.K. Sarma
Aim: Tyrosol, a quorum sensing molecule in yeasts, was reported to reduce lag phase and induces hyphae formation during cell proliferation. However, evidence of any enhancing effect of tyrosol in cellular proliferation within fermentative environment is unclear. In this investigation, selected yeast cells were assessed for their ability to synthesize tyrosol followed by examining the role of the molecule during fermentation. Methods and Results: Tyrosols were characterized in four fermentative yeasts viz., Saccharomyces cerevisiae, Wickerhamomyces anomalus, Candida glabrata and Candida tropicalis isolated from traditional fermentative cakes of northeast India. All the isolates synthesized tyrosol while C. tropicalis exhibited filamentous growth in response to tyrosols retrieved from other isolates. Purified tyrosols showed protective behaviour in C. tropicalis and S. cerevisiae under ethanol mediated oxidative stress. During fermentation, tyrosol significantly enhanced growth of W. anomalus in starch medium while C. tropicalis exhibited growth enhancement in starch and glucose sources. The chief fermentative yeast S. cerevisiae showed notable enhancement in fermentative capacity in starch medium under the influence of tyrosol con-commitment of ethanol production. Conclusion: The study concludes that tyrosol exerts unusual effect in cellular growth and fermentative ability of both Saccharomyces and non-Saccharomyces yeasts. Significance and Impact of the Study: This is the first report of expression of tyrosol by non-conventional yeasts, where the molecule was found to exert enhancing effect during fermentation, thereby augmenting the process of metabolite production during traditional fermentation. © 2020 The Society for Applied Microbiology
Attenuation of metal toxicity by frankial siderophores
(2010) A. Singh; S.S. Singh; P.C. Pandey; A.K. Mishra
In order to investigate the role of frankial siderophores in minimizing metal toxicity, Frankia strains were grown at different concentrations of Mg2+, Cu2+, and Zn2+. Growth was observed up to 500 mmol L-1 Mg2+, 10 μ mol L-1 Cu2+, and 10 μmolL-1 Zn2+ while the maxima were at 200 μmol L-1 Mg2+, 1 μmol L-1 Cu2+, and 1 μmol L-1 Zn2+. The siderophore production was increased up to 500 μmol L-1 Mg2+, 10 μmol L-1 Cu2+, 100 μmol L-1 (hydroxamate type), and 200 μmol L-1 (catecholate type) Zn2+ while maximum production was found at Mg2+ (200 μmol L-1), Cu2+ (10 μmol L-1), and Zn2+ (10 μ molL-1). The results suggested that the growth was protected at higher concentrations of Mg2+ (up to 500 μmol L-1), Cu2+ (10 μ molL-1), and Zn2+ (10 μ mol L-1), possibly due to enhanced siderophore production. Thus, siderophores minimize the metal-induced inhibition of growth in Frankia, likely due to regulation of nutritional imbalances and metabolic processes during adaptation towards metal stress and/or metal toxicity. © 2010 Taylor & Francis.
Bacteriophages: A possible solution to combat enteropathogenic Escherichia coli infections in neonatal goats
(John Wiley and Sons Inc, 2022) K. Bhargava; K. Gururaj; G.K. Aseri; G. Nath; N.P. Singh; R.V.S. Pawaiya; A. Kumar; A.K. Mishra; V.B. Yadav; N. Jain
Due to awareness and benefits of goat rearing in developing economies, goats' significance is increasing. Unfortunately, these ruminants are threatened via multiple bacterial pathogens such as enteropathogenic Escherichia coli (EPEC). In goat kids and lambs, EPEC causes gastrointestinal disease leading to substantial economic losses for farmers and may also pose a threat to public health via the spread of zoonotic diseases. Management of infection is primarily based on antibiotics, but the need for new therapeutic measures as an alternative to antibiotics is becoming vital because of the advent of antimicrobial resistance (AMR). The prevalence of EPEC was established using bfpA gene, uspA gene and Stx1 gene, followed by phylogenetic analysis using Stx1 gene. The lytic activity of the isolated putative coliphages was tested on multi-drug resistant strains of EPEC. It was observed that a PCR based approach is more effective and rapid as compared to phenotypic tests of Escherichia coli virulence. It was also established that the isolated bacteriophages exhibited potent antibacterial efficacy in vitro, with some of the isolates (16%) detected as T4 and T4-like phages based on gp23 gene. Hence, bacteriophages as therapeutic agents may be explored as an alternative to antibiotics in managing public, livestock and environmental health in this era of AMR. © 2022 The Society for Applied Microbiology.
Cultivar specific response of CO2 fertilization on two tropical mung bean (vigna radiata l.) cultivars: ROS generation, antioxidant status, physiology, growth, yield and seed quality
(Blackwell Publishing Ltd, 2014) A.K. Mishra; S.B. Agrawal
Increasing atmospheric carbon dioxide concentration (CO2) is an important component of global climate change that will have a significant impact on the productivity of crop plants. In recent years, growth and yield of agricultural crop plants have been shown to increase with elevated CO2 (EC) and have enticed considerable interest due to variation in the response of crop plants. In this study, comparative response of two mung bean cultivars (HUM-2 and HUM-6) was evaluated against EC at different growth stages under near-natural conditions for two consecutive years. The plants were grown in ambient as well as EC (700 ppm) in specially designed open-top chambers. Under elevated CO2, marked down-regulation of reactive oxygen species (ROS) levels, membrane disruption and activities of superoxide dismutase and catalase were noticed in both the cultivars, but the extent of reduction was more in HUM-6. As compared to ambient CO2, EC increased total chlorophyll, photosynthetic rate, growth and yield parameters. Cultivar-specific response was noticed as HUM-6 showed higher increase in yield attributes than HUM-2. Under CO2 treatment, soluble protein and reducing sugars decreased while total soluble sugars and starch showed an opposite trend. Principal component analysis showed that both the cultivars responded more or less similarly to EC in their respective groupings of physiological and growth parameters, but the magnitude of ROS and antioxidative enzymes was variable. The experimental findings depict that both the cultivars of mung bean showed contrasting response against EC and paved the way for selecting the suitable cultivar having higher productivity in a future high-CO2 environment. © 2014 Blackwell Verlag GmbH.
Cyanobacteria: From Basic Science to Applications
(Elsevier, 2018) A.K. Mishra; D.N. Tiwari; A.N. Rai
Cyanobacteria constitute the most widely distributed group of photosynthetic prokaryotes found in almost all realms of the earth and play an important role in Earth's nitrogen and carbon cycle. The gradual transformation from reducing atmosphere to oxidizing atmosphere was a turning point in the evolutionary history of the earth and made conditions for present life forms possible. Cyanobacteria: From Basic Science to Applications is the first reference volume that comprehensively discusses all aspects of cyanobacteria, including the diverse mechanisms of cyanobacteria for the advancement of cyanobacterial abilities, towards higher biofuel productivity, enhanced tolerance to environmental stress and bioactive compounds and potential for biofertilizers. © 2019 Elsevier Inc. All rights reserved.
dc Polarographic determination of Nitrazepam
(1982) A.K. Mishra; S.K. Bhatt; R.K. Arora; K.D. Gode
[No abstract available]
Design and Application of Nuclear and Molecular Theragnostic Probes
(John Wiley and Sons Inc, 2024) Deepika Sharma; Shubhra Chaturvedi; Ankur Kaul; Sunil Pal; V.P. Singh; A.K. Mishra
With growing propensity towards personalised medication, the application and impact of molecular theragnostic (or, theranostic) is expected to increase dramatically. Molecular theragnostic is the combination of diagnostics and therapeutics in single targeted molecule. If successful, molecular theragnostic will determine the treatment strategy and therapeutic outcome apart from favourably influencing the time of treatment and comfort of the patient. Recent developments such as [64Cu]Cu-ATSM for imaging tumor-hypoxia, 99Y silicate for arthritis, 1⁷⁷Lu-PSMA-617 for prostate cancer etc has been discussed in detail in the literature.[1,2] This sectioned review deals in particular with the development of nuclear molecular theragnostic agents. The genesis and design strategies are presented after compiling recent reports. © 2024 Wiley-VCH GmbH.
Design, development and bio-evaluation of a novel radio-ligand 99mTc-THQ-DTPA as a sigma 2 receptor specific breast tumor imaging agent
(Elsevier Ltd, 2024) Vishakha Chaudhary; Shubhra Chaturvedi; Anju Wadhwa; Ritika Chaudhary; Divya Gautam; Deepika Sharma; Rupesh Kumar; A.K. Mishra
Over-expression of sigma-2 receptor in cancer cells provides an opportunity to develop molecular probes for diagnosis, even for non-receptor specific malignancies like triple negative breast cancers. In this work, a novel sigma-2 receptor ligand [THQ-DTPA] has been synthesized and characterized using 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (THQ) and diethylenetriaminepentaacetic acid (DTPA). The ligand is further chelated with 99mTc for application as metal based radiotracer [99mTc-THQ-DTPA]. Radiolabelling with 99mTc was achieved in an excellent yield of 98.0 ± 0.5% using stannous chloride as a reducing agent. The radioligand was found to be stable in human serum up-to 24 h, bio-compatible with less than 4% hemolysis, and exhibited high binding with sigma receptors isolated from rat liver membrane (Kd of 16.32 ± 4.93 nM and Bmax of 0.5232 ± 0.06 pmol/mg). Bio-distribution studies in triple-negative breast tumor bearing nude mice showed high tumor uptake after 30 min of injection with tumor/muscle (T/M) ratio of 3.58 ± 0.09. At 240 min, the T/M ratio (2.84 ± 0.20) decreased by 35% when administered in sigma blocked tumor bearing mice (1.81 ± 0.16) suggesting the selectivity of the ligand. Tumor imaging in gamma camera indicated a contrast of 3.56 at 30 min p.i. The above findings indicate that the ligand 99mTc-THQ-DTPA binds to sigma-2 receptors with high affinity and has potential for triple-negative breast tumor imaging. © 2023 Elsevier Ltd
DNRA: A short-circuit in biological N-cycling to conserve nitrogen in terrestrial ecosystems
(Elsevier B.V., 2020) C.B. Pandey; Upendra Kumar; Megha Kaviraj; K.J. Minick; A.K. Mishra; J.S. Singh
This paper reviews dissimilatory nitrate reduction to ammonium (DNRA) in soils - a newly appreciated pathway of nitrogen (N) cycling in the terrestrial ecosystems. The reduction of NO3− occurs in two steps; in the first step, NO3− is reduced to NO2−; and in the second, unlike denitrification, NO2− is reduced to NH4+ without intermediates. There are two sets of NO3−/NO2− reductase enzymes, i.e., Nap/Nrf and Nar/Nir; the former occurs on the periplasmic-membrane and energy conservation is respiratory via electron-transport-chain, whereas the latter is cytoplasmic and energy conservation is both respiratory and fermentative (Nir, substrate-phosphorylation). Since, Nir catalyzes both assimilatory- and dissimilatory-nitrate reduction, the nrfA gene, which transcribes the NrfA protein, is treated as a molecular-marker of DNRA; and a high nrfA/nosZ (N2O-reductase) ratio favours DNRA. Recently, several crystal structures of NrfA have been presumed to producee N2O as a byproduct of DNRA via the NO (nitric-oxide) pathway. Meta-analyses of about 200 publications have revealed that DNRA is regulated by oxidation state of soils and sediments, carbon (C)/N and NO2−/NO3− ratio, and concentrations of ferrous iron (Fe2+) and sulfide (S2−). Under low-redox conditions, a high C/NO3− ratio selects for DNRA while a low ratio selects for denitrification. When the proportion of both C and NO3− are equal, the NO2−/NO3− ratio modulates partitioning of NO3−, and a high NO2−/NO3− ratio favours DNRA. A high S2−/NO3− ratio also promotes DNRA in coastal-ecosystems and saline sediments. Soil pH, temperature, and fine soil particles are other factors known to influence DNRA. Since, DNRA reduces NO3− to NH4+, it is essential for protecting NO3− from leaching and gaseous (N2O) losses and enriches soils with readily available NH4+-N to primary producers and heterotrophic microorganisms. Therefore, DNRA may be treated as a tool to reduce ground-water NO3− pollution, enhance soil health and improve environmental quality. © 2020 Elsevier B.V.
Effect of amino acids and its analogues on Gloeotrichia ghosei and its non-nitrogen fixing mutants
(1990) A.K. Mishra; D.N. Tiwari
[No abstract available]
Effect of ammonia and sulfide on rifampicin-induced heterocyst formation in Nostoc linckia
(Springer Netherlands, 1989) D.N. Tiwari; A.K. Mishra; L.J. Singh
The effect of ammonia and sulfide on rifampicin-induced heterocyst differentiation was studied in the nitrogen-fixing cyanobacterium Nostoc linckia. Aerobic growth with nitrogen gas of the cyanobacterium was greatly affected by rifampicin with formation of multiple heterocysts in chains in the filaments whereas ammonia in the medium reversed the rifampicin inhibition of growth and prevented the induction of heterocysts. In a sulfide medium the suppression exerted by rifampicin on aerobic growth with nitrogen gas and heterocyst induction was found to be considerably reduced. The results suggest two interesting points, viz. that (i) rifampicin interferes with the nitrogen-fixing function of heterocysts, and (ii) it checks the synthesis of an unknown heterocyst, inhibitor and thus permits the adjacent vegetative cells to differentiate into heterocysts in chains. © 1989 ACADEMIA, Publishing House of the Czechoslovak Academy of Sciences.
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.
Effect of seeding method and fertilizer application on weed biomass and yield of wheat (Triticum aestivum)
(1999) A.K. Mishra; R.C. Tiwari
A field experiment was conducted on sandy loam soil analysing low in N and medium in P and K during rabi season of 1993-94 and 194-95 at Varanasi to evaluate the effect of different methods of sowing and fertilizer application in wheat (Triticum aestivum L. emend. Fiori & Paol.). Line sowing and placement of fertilizer in rows 5 cm below the seed showed significant reduction in weed biomass and increased the yield of wheat over broadcast sowing and fertilizer application. Seed emergence was markedly reduced when fertilizer and seed were mixed and then sown in rows. The root weight of plants grown with broadcast sowing was lower than of row sown crop. The row sowing of seed and placement of fertilizer in rows or broadcast of fertilizer but sowing of seed in rows removed higher amount of N, P and K than broadcast of seed and fertilizers.
Effect of tryptophan on 2,4‐dichlorophenoxyacetic acid toxicity in the nitrogen‐fixing‐cyanobacterium Nostoc linckia
(1986) A.K. Mishra; D.N. Tiwari
The combined effect of a hormone weed killer 2,4‐dichlorophenoxyacetic acid (2,4‐D) and an amino acid (tryptophan) has been studied on growth and heterocyst differentiation in the cyanobacterium Nostoc linckia. 2.4‐D at 100 μg/ml stimulated growth and heterocyst frequency in combined nitrogen‐free medium while its higher concentrations inhibited both. Tryptophan under similar conditions promoted much growth yield with 3–4 fold enhanced heterocyst frequency than the control. Such heterocysts were immature and showed germination under in situ condition. The concentrations of 2,4‐D (100 μg/ml) and tryptophan (50 μg/ml), stimulatory to growth and heterocyst formation, caused additive effect while herbicide inhihibition of nitrogen‐fixing growth at higher doses was partially relieved by tryptophan but tryptophan‐induced heterocyst frequency was completely suppressed under this condition. The possible role of interaction of these two chemicals on growth and heterocyst formation has been discussed. Copyright © 1986 Wiley‐VCH
Effects of three pesticides on MSX-induced ammonia photoproduction by the cyanobacterium Nostoc linckia
(1989) A.K. Mishra; A.B. Pandey; H.D. Kumar
Three pesticides (2,4-D, basalin, aldrin) inhibited l-methionine-dl-sulfoximine (MSX)-induced photoproduction of ammonia by the nitrogen-fixing cyanobacterium Nostoc linckia. Combinations of pesticides and MSX were inhibitory except at low concentrations (100 and 500 μg/ml) of 2,4-D which stimulated NH4+ production. Similar results were obtained when pesticides were added 6 hr after the addition of MSX, but the inhibition was weaker. When MSX was added to the culture 6 hr after the addition of pesticides, the pesticides stimulated NH4+ photoproduction. Similar results were obtained on nitrogenase activity of the organism. © 1989.
Emerging Proteases for Molecular Imaging and Therapy in Cancer
(CRC Press, 2024) Presenjit; Shubhra Chaturvedi; A.K. Mishra; Vishakha Chaudhary; V.P. Singh; Kaman Singh
Proteases, enzymes specializing in cleaving peptide linkages within proteins, perform a pivotal role in normal biological processes and regulating various disease states. Recent research has underscored the fundamental significance of proteolysis in controlling biological functions and managing diseases, spurring intense interest in developing methods to visualize protease activity. Unlike conventional approaches, molecular imaging provides comprehensive insights into tumor location, expression profiles, and microenvironmental markers. Imaging proteases may enable early cancer identification and tailored therapeutic interventions. This chapter highlights the crucial role of molecular imaging in the realm of cancer detection and treatment, with a particular focus on proteases implicated in tumor growth. © 2025 selection and editorial matter, Sajal Chakraborti individual chapters, the contributors.
Enhancement of NTG mutagenesis by chloramphenicol in Gloeotrichia ghosei
(Springer-Verlag, 1985) A.K. Mishra; D.N. Tiwari
The mutagenisity of NTG (N-methyl-N-nitro-N-nitrosoguanidine) for Gloeotrichia ghosei, a cyanobacterium, was enhanced by simultaneous treatment with NTG and chloramphenicol with minimal effect on survival. Addition of chloramphenicol at the time of NTG treatment enhanced the mutation frequency of the fil5marker considerably (about ten times). © 1985 Springer-Verlag.