19 results on '"Phukan T"'
Search Results
2. Study of optical properties of swift heavy ion irradiated PADC polymer
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Phukan, T., Kanjilal, D., Goswami, T.D., and Das, H.L.
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- 2003
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Catalog
3. Optical and electrical properties of gamma irradiated PADC detector
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Sinha, D, Phukan, T, Tripathy, S.P, Mishra, R, and Dwivedi, K.K
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- 2001
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4. An Innovative Root Inoculation Method to Study Ralstonia solanacearum Pathogenicity in Tomato Seedlings
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Singh, N., primary, Phukan, T., additional, Sharma, P. L., additional, Kabyashree, K., additional, Barman, A., additional, Kumar, R., additional, Sonti, R. V., additional, Genin, S., additional, and Ray, S. K., additional more...
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- 2018
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5. Dielectric response of heavy ion irradiated PADC track detector
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Phukan, T, Kanjilal, D, Goswami, T.D, and Das, H.L
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- 1999
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6. Ralstonia solanacearum virulence in tomato seedlings inoculated by leaf clipping
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Kumar, R., primary, Barman, A., additional, Phukan, T., additional, Kabyashree, K., additional, Singh, N., additional, Jha, G., additional, Sonti, R. V., additional, Genin, S., additional, and Ray, S. Kumar, additional more...
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- 2016
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7. Ralstonia solanacearum virulence in tomato seedlings inoculated by leaf clipping.
- Author
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Kumar, R., Barman, A., Phukan, T., Kabyashree, K., Singh, N., Jha, G., Sonti, R. V., Genin, S., and Ray, S. Kumar
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SEEDLING diseases & pests ,TOMATOES ,RALSTONIA solanacearum ,MICROBIAL virulence ,BACTERIAL colonies - Abstract
Ralstonia solanacearum is a phytopathogenic bacterium that colonizes the xylem vessels of host plants leading to a lethal wilt disease. Although several studies have investigated the virulence of R. solanacearum on adult host plants, infection studies of this pathogen on the seedling stages of hosts are less common. In a preliminary observation, inoculation of R. solanacearum F1C1 on 6-to 7-day-old tomato seedlings by a simple leaf-clip strategy resulted in a lethal pathogenic condition in seedlings that eventually killed these seedlings within a week post-inoculation. This prompted testing of the effect of this inoculation technique in seedlings from different cultivars of tomato and similar results were obtained. Colonization and spread of the bacteria throughout the infected seedlings was demonstrated using gus-tagged R. solanacearum F1C1. The same method of inoculating tomato seedlings was used with R. solanacearum GMI1000 and independent mutants of R. solanacearum GMI1000, deficient in the virulence genes hrpB, hrpG, phcA and gspD. Wildtype R. solanacearum GMI1000 was found to be virulent on tomato seedlings, whereas the mutants were found to be non-virulent. This leaf-clip technique, for inoculation of tomato seedlings, has the potential to be a valuable approach, saving time, space, labour and costs. [ABSTRACT FROM AUTHOR] more...
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- 2017
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8. Changes in electrical properties in α- and γ-exposed PADC track detector
- Author
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Phukan, T, primary, Dwivedi, K.K, additional, Goswami, T.D, additional, and Das, H.L, additional
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- 2001
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9. Changes in electrical properties in a- and g-exposed PADC track detector
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Phukan, T., Dwivedi, K. K., Goswami, T. D., and Das, H. L.
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- 2001
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10. Externally supplied ascorbic acid moderates detrimental effects of UV-C exposure in cyanobacteria.
- Author
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Phukan T, Ryntathiang S, and Syiem MB
- Subjects
- Nostoc muscorum drug effects, Nostoc muscorum metabolism, Nostoc muscorum chemistry, Lipid Peroxidation drug effects, Bacterial Proteins metabolism, Ascorbic Acid pharmacology, Ascorbic Acid chemistry, Ultraviolet Rays, Reactive Oxygen Species metabolism
- Abstract
The defensive role performed by exogenously supplied ascorbic acid in the cyanobacterium Nostoc muscorum Meg1 against damages produced by UV-C radiation exposure was assessed in this study. Exposure to UV-C (24 mJ/cm
2 ) significantly enhanced reactive oxygen species (ROS) (50%) along with peroxidation of lipids (21%) and protein oxidation (22%) in the organism. But, addition of 0.5 mM ascorbic acid prior to UV-C exposure showed reduction in ROS production (1.7%) and damages to lipids and proteins (1.5 and 2%, respectively). Light and transmission electron microscopic studies revealed that ascorbic acid not only protected filament breakage but also restricted severe ultrastructural changes and cellular damages in the organism. Although the growth of the organism was repressed up to 9% under UV-C treatment within 15 days, a pre-treatment with ascorbic acid led to growth enhancement by 42% in the same period. Various growth parameters such as photo-absorbing pigments (phycoerythrin, phycocyanin, allophycocyanin, chlorophyll a, and carotenoids), water splitting complex (WSC), D1 protein, RuBisCO, glutamine synthetase and nitrogenase activities in the UV-C treated organism were seen to be relatively intact in the presence of ascorbic acid. Thus, a detailed analysis undertaken in the present study was able to demonstrate that ascorbic acid not only act as first responder against harmful UV-C radiation by down-regulating ROS production, it also accelerated the growth performance in the organism in the post UV-C incubation period as an immediate response to an adverse experience presented in the form of UV-C radiation exposure., (© 2024. The Author(s), under exclusive licence to the European Photochemistry Association, European Society for Photobiology.) more...- Published
- 2024
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11. Impact of polyvinyl chloride (PVC) microplastic on growth, photosynthesis and nutrient uptake of Solanum lycopersicum L. (Tomato).
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Nuamzanei, Changmai U, Sk S, Kumar N, Borah B, Chikkaputtaiah C, Saikia R, and Phukan T
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- Nutrients metabolism, Plant Roots drug effects, Plant Roots metabolism, Plant Roots growth & development, Chlorophyll metabolism, Reactive Oxygen Species metabolism, Solanum lycopersicum drug effects, Solanum lycopersicum growth & development, Solanum lycopersicum metabolism, Polyvinyl Chloride, Soil Pollutants toxicity, Soil Pollutants metabolism, Photosynthesis drug effects, Microplastics toxicity
- Abstract
Microplastics (MPs) pollution and their impact on plants have become a global threat, but their effect at the molecular level remains scarce. This study aims to gain insight into the effects of polyvinylchloride microplastic (PVC-MP) on tomato plants at the genetic and protein levels. In this study, we found that increasing concentrations of PVC-MP (2.5, 5,7.5, and 10% w/w) in the soil did not cause any phytotoxic (chlorosis or necrosis) symptoms but it did result in a dose-dependent reduction in plant growth-related parameters, such as height, leaf area, stem diameter, and plant fresh and dry weight. Additionally, the number of secondary roots was reduced while the primary roots were elongated. Furthermore, PVC-MP also caused a significant decrease in light-harvesting pigments chlorophylls, and carotenoids while increasing the level of reactive oxygen species (ROS) and lipid peroxidation in plants. Microscopic analysis of the roots revealed the uptake of PVC-MP of size less than 10 μm. Micro- and macro-element analysis showed changes in concentrations of Ca, Cu, Fe, Mg, Mn, Ni, and Zn, upon PVC-MP exposure. Results from western blotting and q-PCR showed that higher doses of PVC-MP significantly reduced the CO
2 -fixing enzyme RuBisCO and D1 proteins of PSII at both protein and transcript levels. These findings suggest that lower levels of light-harvesting pigments, D1 protein, RuBisCO, and modulation of nutrient absorption are among the factors responsible for growth suppression in tomato plants upon exposure to PVC-MP. As tomato plants are economically significant crops, an increase in PVC-MP in agricultural fields may have a detrimental influence on crop production, resulting in economic loss., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.) more...- Published
- 2024
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12. Seroepidemiological and genomic investigation of SARS-CoV-2 spread in North East region of India.
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Wahengbam R, Bharali P, Manna P, Phukan T, Singh MG, Gogoi G, Tapadar YB, Singh AK, Konwar R, Chikkaputtaiah C, Velmurugan N, Nagamani S, Mahanta HJ, Sarma H, Sahu RK, Dutta P, Wann SB, Kalita J, and Sastry GN more...
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- Humans, Seroepidemiologic Studies, Genomics, India epidemiology, Antibodies, Neutralizing, SARS-CoV-2 genetics, COVID-19 epidemiology
- Abstract
Purpose: Seroepidemiology and genomic surveillance are valuable tools to investigate infection transmission during a pandemic. North East (NE) India is a strategically important region being the gateway connecting the country with Southeast Asia. Here, we examined the spread of SARS-CoV-2 in NE India during the first and second waves of COVID-19 using serological and whole genome sequencing approaches., Methods: qRT-PCR analysis was performed on a selected population (n = 16,295) from June 2020 to July 2021, and metadata was collected. Immunoassays were studied (n = 2026) at three-time points (August 2020, February 2021, and June 2021) and in a cohort (n = 35) for a year. SARS-CoV-2 whole genomes (n = 914) were sequenced and analyzed with those obtained from the databases., Results: Test positivity rates (TPR) in the first and second waves were 6.34% and 6.64% in Assam, respectively, and a similar pattern was observed in other NE states. Seropositivity in the three time points was 10.63%, 40.3%, and 46.33%, respectively, and neutralizing antibody prevalence was 90.91%, 52.14%, and 69.30%, respectively. Persistence of pan-IgG-N SARS-CoV-2 antibody for over a year was observed among three subjects in the cohort group. Normal variants dominated the first wave, while B.1.617.2 and AY-sublineages dominated the second wave in the region. The prevalence of the variants co-related well with high TPR and seropositivity rate in the region and identified mostly among vaccinated individuals., Conclusion: The COVID-19 first wave in the region witnessed low transmission with the evolution of diverse variants. Seropositivity increased during the study period with over half of the individuals carrying neutralizing antibodies against SARS-CoV-2. High infection and seroprevalence in NE India during the second wave were associated with the dominant emergence of variants of concern., (Copyright © 2022 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved.) more...
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- 2023
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13. A machine learning-based approach to determine infection status in recipients of BBV152 (Covaxin) whole-virion inactivated SARS-CoV-2 vaccine for serological surveys.
- Author
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Singh P, Ujjainiya R, Prakash S, Naushin S, Sardana V, Bhatheja N, Singh AP, Barman J, Kumar K, Gayali S, Khan R, Rawat BS, Tallapaka KB, Anumalla M, Lahiri A, Kar S, Bhosale V, Srivastava M, Mugale MN, Pandey CP, Khan S, Katiyar S, Raj D, Ishteyaque S, Khanka S, Rani A, Promila, Sharma J, Seth A, Dutta M, Saurabh N, Veerapandian M, Venkatachalam G, Bansal D, Gupta D, Halami PM, Peddha MS, Veeranna RP, Pal A, Singh RK, Anandasadagopan SK, Karuppanan P, Rahman SN, Selvakumar G, Venkatesan S, Karmakar MK, Sardana HK, Kothari A, Parihar DS, Thakur A, Saifi A, Gupta N, Singh Y, Reddu R, Gautam R, Mishra A, Mishra A, Gogeri I, Rayasam G, Padwad Y, Patial V, Hallan V, Singh D, Tirpude N, Chakrabarti P, Maity SK, Ganguly D, Sistla R, Balthu NK, A KK, Ranjith S, Kumar BV, Jamwal PS, Wali A, Ahmed S, Chouhan R, Gandhi SG, Sharma N, Rai G, Irshad F, Jamwal VL, Paddar MA, Khan SU, Malik F, Ghosh D, Thakkar G, Barik SK, Tripathi P, Satija YK, Mohanty S, Khan MT, Subudhi U, Sen P, Kumar R, Bhardwaj A, Gupta P, Sharma D, Tuli A, Ray Chaudhuri S, Krishnamurthi S, Prakash L, Rao CV, Singh BN, Chaurasiya A, Chaurasiyar M, Bhadange M, Likhitkar B, Mohite S, Patil Y, Kulkarni M, Joshi R, Pandya V, Mahajan S, Patil A, Samson R, Vare T, Dharne M, Giri A, Mahajan S, Paranjape S, Sastry GN, Kalita J, Phukan T, Manna P, Romi W, Bharali P, Ozah D, Sahu RK, Dutta P, Singh MG, Gogoi G, Tapadar YB, Babu EV, Sukumaran RK, Nair AR, Puthiyamadam A, Valappil PK, Pillai Prasannakumari AV, Chodankar K, Damare S, Agrawal VV, Chaudhary K, Agrawal A, Sengupta S, and Dash D more...
- Subjects
- COVID-19 Vaccines therapeutic use, Humans, Machine Learning, Pandemics, SARS-CoV-2, Vaccines, Inactivated, Virion, COVID-19 epidemiology, COVID-19 prevention & control, Viral Vaccines
- Abstract
Data science has been an invaluable part of the COVID-19 pandemic response with multiple applications, ranging from tracking viral evolution to understanding the vaccine effectiveness. Asymptomatic breakthrough infections have been a major problem in assessing vaccine effectiveness in populations globally. Serological discrimination of vaccine response from infection has so far been limited to Spike protein vaccines since whole virion vaccines generate antibodies against all the viral proteins. Here, we show how a statistical and machine learning (ML) based approach can be used to discriminate between SARS-CoV-2 infection and immune response to an inactivated whole virion vaccine (BBV152, Covaxin). For this, we assessed serial data on antibodies against Spike and Nucleocapsid antigens, along with age, sex, number of doses taken, and days since last dose, for 1823 Covaxin recipients. An ensemble ML model, incorporating a consensus clustering approach alongside the support vector machine model, was built on 1063 samples where reliable qualifying data existed, and then applied to the entire dataset. Of 1448 self-reported negative subjects, our ensemble ML model classified 724 to be infected. For method validation, we determined the relative ability of a random subset of samples to neutralize Delta versus wild-type strain using a surrogate neutralization assay. We worked on the premise that antibodies generated by a whole virion vaccine would neutralize wild type more efficiently than delta strain. In 100 of 156 samples, where ML prediction differed from self-reported uninfected status, neutralization against Delta strain was more effective, indicating infection. We found 71.8% subjects predicted to be infected during the surge, which is concordant with the percentage of sequences classified as Delta (75.6%-80.2%) over the same period. Our approach will help in real-world vaccine effectiveness assessments where whole virion vaccines are commonly used., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.) more...
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- 2022
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14. Insights from a Pan India Sero-Epidemiological survey (Phenome-India Cohort) for SARS-CoV2.
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Naushin S, Sardana V, Ujjainiya R, Bhatheja N, Kutum R, Bhaskar AK, Pradhan S, Prakash S, Khan R, Rawat BS, Tallapaka KB, Anumalla M, Chandak GR, Lahiri A, Kar S, Mulay SR, Mugale MN, Srivastava M, Khan S, Srivastava A, Tomar B, Veerapandian M, Venkatachalam G, Vijayakumar SR, Agarwal A, Gupta D, Halami PM, Peddha MS, Sundaram GM, Veeranna RP, Pal A, Agarwal VK, Maurya AK, Singh RK, Raman AK, Anandasadagopan SK, Karuppanan P, Venkatesan S, Sardana HK, Kothari A, Jain R, Thakur A, Parihar DS, Saifi A, Kaur J, Kumar V, Mishra A, Gogeri I, Rayasam G, Singh P, Chakraborty R, Chaturvedi G, Karunakar P, Yadav R, Singhmar S, Singh D, Sarkar S, Bhattacharya P, Acharya S, Singh V, Verma S, Soni D, Seth S, Vashisht S, Thakran S, Fatima F, Singh AP, Sharma A, Sharma B, Subramanian M, Padwad YS, Hallan V, Patial V, Singh D, Tripude NV, Chakrabarti P, Maity SK, Ganguly D, Sarkar J, Ramakrishna S, Kumar BN, Kumar KA, Gandhi SG, Jamwal PS, Chouhan R, Jamwal VL, Kapoor N, Ghosh D, Thakkar G, Subudhi U, Sen P, Chaudhury SR, Kumar R, Gupta P, Tuli A, Sharma D, Ringe RP, D A, Kulkarni M, Shanmugam D, Dharne MS, Dastager SG, Joshi R, Patil AP, Mahajan SN, Khan AH, Wagh V, Yadav RK, Khilari A, Bhadange M, Chaurasiya AH, Kulsange SE, Khairnar K, Paranjape S, Kalita J, Sastry NG, Phukan T, Manna P, Romi W, Bharali P, Ozah D, Sahu RK, Babu EV, Sukumaran R, Nair AR, Valappil PK, Puthiyamadam A, Velayudhanpillai A, Chodankar K, Damare S, Madhavi Y, Aggarwal VV, Dahiya S, Agrawal A, Dash D, and Sengupta S more...
- Subjects
- Biomarkers blood, COVID-19 diagnosis, COVID-19 immunology, COVID-19 virology, Female, Host-Pathogen Interactions, Humans, Immunity, Humoral, India epidemiology, Longitudinal Studies, Male, Predictive Value of Tests, Risk Assessment, Risk Factors, Seroepidemiologic Studies, Time Factors, Antibodies, Neutralizing blood, Antibodies, Viral blood, COVID-19 epidemiology, COVID-19 Serological Testing, SARS-CoV-2 immunology
- Abstract
To understand the spread of SARS-CoV2, in August and September 2020, the Council of Scientific and Industrial Research (India) conducted a serosurvey across its constituent laboratories and centers across India. Of 10,427 volunteers, 1058 (10.14%) tested positive for SARS-CoV2 anti-nucleocapsid (anti-NC) antibodies, 95% of which had surrogate neutralization activity. Three-fourth of these recalled no symptoms. Repeat serology tests at 3 (n = 607) and 6 (n = 175) months showed stable anti-NC antibodies but declining neutralization activity. Local seropositivity was higher in densely populated cities and was inversely correlated with a 30-day change in regional test positivity rates (TPRs). Regional seropositivity above 10% was associated with declining TPR. Personal factors associated with higher odds of seropositivity were high-exposure work (odds ratio, 95% confidence interval, p value: 2.23, 1.92-2.59, <0.0001), use of public transport (1.79, 1.43-2.24, <0.0001), not smoking (1.52, 1.16-1.99, 0.0257), non-vegetarian diet (1.67, 1.41-1.99, <0.0001), and B blood group (1.36, 1.15-1.61, 0.001)., Competing Interests: SN, VS, RU, NB, RK, AB, SP, SP, RK, BR, KT, MA, GC, AL, SK, SM, MM, MS, SK, AS, BT, MV, GV, SV, AA, DG, PH, MP, GS, RV, AP, VA, AM, RS, AR, SA, PK, SV, HS, AK, RJ, AT, DP, AS, JK, VK, AM, IG, GR, PS, RC, GC, PK, RY, SS, DS, SS, PB, SA, VS, SV, DS, SS, SV, ST, FF, AS, AS, BS, MS, YP, VH, VP, DS, NT, PC, SM, DG, JS, SR, BK, KK, SG, PJ, RC, VJ, NK, DG, GT, US, PS, SC, RK, PG, AT, DS, RR, AD, MK, DS, MD, SD, RJ, AP, SM, AK, VW, RY, AK, MB, AC, SK, KK, SP, JK, NS, TP, PM, WR, PB, DO, RS, EB, RS, AN, PV, AP, AV, KC, SD, YM, VA, SD, AA, DD, SS No competing interests declared, (© 2021, Naushin et al.) more...
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- 2021
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15. An efficient low-cost xylem sap isolation method for bacterial wilt assays in tomato.
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Longchar B, Phukan T, Yadav S, and Senthil-Kumar M
- Abstract
Premise: A portable, simple, yet efficient method was developed for the rapid extraction of xylem sap from the stems and petioles of tomato plants for diagnostic and quantification assays of the xylem-colonizing wilt bacterium Ralstonia solanacearum ., Methods and Results: Xylem saps were extracted from tomato stem sections using negative pressure generated from handheld needleless syringes. The samples were collected from plants grown under different soil moisture levels at four days after inoculation with the pathogen. Pipette tips were modified to serve as adapters for the stem sections. The quantification of the bacterial load in the extracted sap was performed by plating sap dilutions in Kelman's triphenyltetrazolium chloride (TTC) medium. Pathogen identity was further confirmed by performing a PCR using R . solanacearum -specific primers., Conclusions: Due to its simplicity, portability, and thoroughness of extraction from predetermined tissue sizes, the method can potentially facilitate high-throughput onsite sampling from a large number of samples in a short time, which cannot be achieved with other available techniques., (© 2020 Longchar et al. Applications in Plant Sciences is published by Wiley Periodicals, Inc. on behalf of the Botanical Society of America.) more...
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- 2020
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16. Dynamics of Mycobacteriophage-Mycobacterial Host Interaction.
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Ghosh A, Phukan T, Johari S, Sharma A, Vashista A, and Sinha S
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- Animals, Computational Biology, Enzymes pharmacology, Host-Pathogen Interactions, Humans, Machine Learning, Mycobacterium drug effects, Mycobacterium virology, Mycobacterium Infections drug therapy, Phage Therapy, Mycobacteriophages physiology, Mycobacterium growth & development, Mycobacterium Infections prevention & control
- Abstract
Mycobacterium sp. is exhibiting complex evolution of antimicrobial resistance (AMR) and can therefore be considered as a serious human pathogen. Many strategies were employed earlier to evade the pathogenesis but AMR became threatened. Molecular tools employing bacteriophage can be an alternative to effective treatment against Mycobacterium. Phage treatment using phage-encoded products, such as lysins, causes lysis of cells; particularly bacteria could be used instead of direct use of these bacteriophages. Modern technologies along with bacteriophage strategies such as in silico immunoinformatics approach, machine learning, and artificial intelligence have been described thoroughly to escape the pathogenesis. Therefore, understanding the molecular mechanisms could be a possible alternative to evade the pathogenesis. more...
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- 2020
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17. Unstandardized UV-C dose used for killing harmful cyanobacteria may instead initiate accelerated growth in the target organisms.
- Author
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Phukan T, Rai AN, and Syiem MB
- Subjects
- Glutamate-Ammonia Ligase metabolism, Nitrogenase metabolism, Nostoc muscorum enzymology, Nostoc muscorum growth & development, Nostoc muscorum metabolism, Photosynthesis, Photosystem II Protein Complex metabolism, Ribulose-Bisphosphate Carboxylase metabolism, Nostoc muscorum radiation effects, Ultraviolet Rays
- Abstract
Although UV-C radiation has been in use for killing unwanted cyanobacteria, experiments with lower doses of UV-C radiation instead showed induction of growth related parameters and enhanced biomass production in the cyanobacterium Nostoc muscorum Meg1. When the cyanobacterial cultures were exposed to UV-C radiation of varying doses (6, 12 and 18 mJ/cm
2 ), concentrations of various photo-absorbing pigments, RuBisCO and D1 protein of PSII; activities of oxygen evolving complex, nitrogenase and glutamine synthetase were significantly increased upon 6 and 12 mJ/cm2 UV-C radiation exposures. Resulting higher photosynthetic performance was evident from the augmentation in carbohydrate content by ∼49% under single exposure to 6 mJ/cm2 UV-C by fifteenth day. The increased performances of both RuBisCO and D1 proteins were in part also due to induction at the genetic level as seen from the increase in their mRNA and protein levels under treatment. Similar increase was also observed in protein (16%) and in lipid contents (43%) that reflected an upsurge in the total biomass. Highest biomass (463 mg/L/d) was noted in culture exposed to 6 mJ/cm2 UV-C radiation, representing a ∼25% increase. Furthermore the possibility of this organism using part of the incident UV-C radiation as an additional source of energy was deduced from an experiment where the thylakoid membranes excited within UV (226-400 nm) range showed emission at longer wavelengths with an emission maximum at ∼640 nm. Thus this work provides evidence that lower UV-C doses can potentially augment cyanobacterial growth and use of unstandardized UV-C doses for restricting cyanobacterial growth may in fact produce contrary result., (Copyright © 2019 Elsevier Inc. All rights reserved.) more...- Published
- 2019
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18. Modulation of oxidant and antioxidant homeostasis in the cyanobacterium Nostoc muscorum Meg1 under UV-C radiation stress.
- Author
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Phukan T and Syiem MB
- Subjects
- Ascorbic Acid metabolism, Catalase metabolism, Cysteine metabolism, Flavonoids metabolism, Glutathione metabolism, Glutathione Reductase metabolism, Lipid Peroxidation drug effects, Lipid Peroxidation radiation effects, Nostoc muscorum ultrastructure, Oxidation-Reduction, Oxidative Stress drug effects, Oxidative Stress radiation effects, Proline metabolism, RNA, Messenger genetics, RNA, Messenger metabolism, Reactive Oxygen Species metabolism, Superoxide Dismutase metabolism, Water Pollutants, Chemical toxicity, Antioxidants metabolism, Homeostasis, Nostoc muscorum physiology, Nostoc muscorum radiation effects, Oxidants metabolism, Stress, Physiological radiation effects, Ultraviolet Rays
- Abstract
The present work was conducted to study how restoration of perturbed oxidant and antioxidant homeostasis is achieved in the UV-C radiation exposed cells of cyanobacterium Nostoc muscorum Meg1. Exposure to varying doses of UV-C radiation (6, 12, 18 and 24 mJ/cm
2 ) showed damage to ultrastructures especially cytoplasmic membrane, cell wall and organisation of thylakoid membranes of the cyanobacterium under transmission electron microscope (TEM). All doses of UV-C exposure significantly induced most of the enzymatic antioxidant {catalase, superoxide dismutase (SOD) and glutathione reductase (GR)} activities, their protein levels (western blot analysis) and mRNA levels (real time PCR analysis) within the first hour of post UV-C radiation incubation period. In the same way, contents of many non-enzymatic antioxidants such as ascorbic acid, reduced glutathione, proline, phenol and flavonoids were also augmented in response to such UV-C radiation exposure. Although notable increase in ROS level was only seen in cultures treated with 24 mJ/cm2 UV-C exposure which also registered increase in protein oxidation (22%) and lipid peroxidation (20%), this boost in both enzymatic and non-enzymatic antioxidants was significant in all radiation exposed cells indicating cell's preparation to combat rise in oxidants. Further, albeit all antioxidants increased considerably, their levels were restored back to control values by day seventh re-establishing physiological redox state for normal metabolic function. The combined efficiency of the enzymatic and non-enzymatic antioxidants were so effective that they were able to bring down the increase levels of ROS, lipid peroxidation and protein oxidation to the physiological levels within 1 h of radiation exposure signifying their importance in the defensive roles in protecting the organism from oxidative toxicity induced by UV-C radiation exposure., (Copyright © 2019 Elsevier B.V. All rights reserved.) more...- Published
- 2019
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19. Dose dependent variance in UV-C radiation induced effects on carbon and nitrogen metabolism in the cyanobacterium Nostoc muscorum Meg1.
- Author
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Phukan T, Rai AN, and Syiem MB
- Subjects
- Glutamate-Ammonia Ligase metabolism, Lipid Peroxidation radiation effects, Microscopy, Electron, Transmission, Nitrogenase metabolism, Nostoc muscorum growth & development, Nostoc muscorum metabolism, Nostoc muscorum ultrastructure, Reactive Oxygen Species metabolism, Ribulose-Bisphosphate Carboxylase metabolism, Carbon metabolism, Nitrogen metabolism, Nostoc muscorum radiation effects, Ultraviolet Rays
- Abstract
With the intention of getting an insight into the differential effect of UV-C radiation on the N
2 -fixing heterocystous cyanobacterium Nostoc muscorum Meg1, various aspects of carbon and nitrogen metabolism was evaluated in the organism. Exposure to different doses of UV-C (6, 12, 18 and 24 mJ/cm2 ) showed that among various photo-absorbing pigments, phycobiliproteins were most sensitive. Oxygen evolving complex (OEC) activity measured as net oxygen evolution rate decreased by 63% upon 24 mJ/cm2 exposure. Western blot analysis established that D1 protein of PSII was highly sensitive and its levels decreased even at a radiation dose as low as 6 mJ/cm2 . In contrast, levels of the Calvin cycle enzyme RuBisCO was increased at 6 and 12 mJ/cm2 doses but the level decreased drastically (84%) at higher dose (24 mJ/cm2 ). The nitrogenase enzyme activity decreased at all doses but the ammonia assimilating enzyme glutamine synthetase (GS) activity recorded increase at the lower doses. The reactive oxygen species (ROS) and lipid peroxidation increased upon UV-C exposure. Transmission electron microscopic observation revealed damage to ultrastructure especially the thylakoid membrane organization, aggregation of dissolving phycobilisomes and loss of caboxysomes. Interestingly, sub-lethal radiation (6 and 12 mJ/cm2 ) dose exposures increased the growth rate in the organism when growth was measured over a period of 11 days after radiation exposure., (Copyright © 2018 Elsevier Inc. All rights reserved.) more...- Published
- 2018
- Full Text
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