Browsing by Author "Shweta Yadav"

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Antimicrobial activity of some cyanobacteria
(2012) Shweta Yadav; Rajeshwar P. Sinha; Madhu B. Tyagi
Fifteen cyanobacteria belonging to Anabaena, Nostoc, Scytonema and Microcystis species isolated from various aquatic and terrestrial habitats were screened for antimicrobial activity. A disc diffusion assay was used to detect the antimicrobial activity of crude hydrophilic and lipophilic extracts as well as culture supernatants of cyanobacteria on solid agar medium. Methanolic extracts of Anabaena BT2, Nostoc Brf02, Nostoc Brf04 and Scytonema br1 at a concentration of 500 μg/disc showed prominent zone of inhibition against two Gram-negative bacteria (Pseudomonas sb1 and sb3). In liquid cultures addition of 500 μg/ml crude extracts produced 72-78 % growth inhibition of test bacteria. Out of all the cyanobacteria tested only the methanolic extract of Microcystis and chloroform fraction of Scytonema br1 showed significant anticyanobacterial activity against Anabaena BT2 and Nostoc pbr01 and antialgal activity against a green alga Bracteacoccus. In liquid cultures a concentration of 300 μg/ml of these extracts produced 73-85 % growth inhibition of the test organisms. None of the culture filtrates showed any antimicrobial activity.
COVID-19 and waste management in Indian scenario: challenges and possible solutions
(Springer Science and Business Media Deutschland GmbH, 2021) Richa Kothari; Sinha Sahab; Har Mohan Singh; Rajeev Pratap Singh; Bhaskar Singh; Deepak Pathania; Anita Singh; Shweta Yadav; Tanu Allen; Sohini Singh; Vineet Veer Tyagi
The outbreak of COVID-19 pandemic has created havoc all across the globe causing exponential casualties and tremendous health and economic loss. With increasing COVID-19 cases, the amount of biomedical waste has increased manifolds making more people vulnerable to the pandemic. The developing and underdeveloped countries are already facing the challenges of waste management, and the waste generated during the pandemic scenario has added to the already existing challenges. The improper waste management practices need to be corrected; otherwise, the world will be facing a new disaster that could be termed as ‘waste disaster’. The increase in COVID-19-associated waste (CAW) quantity and their availability in the environment will result in their easy approach to other organisms, which will possibly increase the potential risk of food chain contamination. Some of the countries have already started to make backup plans and are struggling to overcome the ‘waste disaster’. In light of the limited knowledge available on the mutational properties and possible hosts of this newly emerged COVID-19, there is a great demand to have an efficient strategy to prevent the environment from further contamination in India. The necessity of the prevailing time is to create a more efficient, automatic, mechanized, and well-modified waste management system for handling the present situation and delaying the projected waste disaster in the near future in the era of COVID-19. The article aims to address the issues that originated from waste discharges, their potential sources along with possible sustainable solutions. Graphical abstract: [Figure not available: see fulltext.] © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Cyanobacterial secondary metabolites
(2011) Shweta Yadav; R.P. Sinha; M.B. Tyagi; Ashok Kumar
Cyanobacteria inhabit a range of diverse and extreme habitats and have potential to produce an elaborate array of secondary metabolites with unusual structures and potent bioactivity. This review summarizes several classes of cyanobacterial secondary metabolites some of which pose a threat to human or animal health in aquatic ecosystems because of their acute toxicity. This class includes hepatotoxins (microcystins and nodularins), neurotoxins (saxitoxin and anatoxins) and irritant toxins (lipopolysachharides). Another important class includes the phytohormones (IAAs, cytokinin and gibberillin-like compounds) and iron-chelators (schizokinen, anachelin and synechobactins) which besides exerting profound effect on the productivity of the ecosystem have also potential for use as medicine for treatment of persistent metal toxicity. Several cyclic peptides and depsipeptides such as cyanopeptolins, micropeptin and oscillaeptin which have been categorized as protease inhibitors make cyanobacteria unattractive as a food source to grazers and help in their survival. UV-screening compounds such as scytonemin and mycosporin-like amino acids (MAAs) produced by cyanobacteria inhabiting habitats exposed to intense solar radiation may find use in development of artificial sunscreens.
Diversity analysis and risk assessment of microplastics in terrestrial soil across different landuses of northern India
(Elsevier Inc., 2025) Ekta Gupta; Shweta Yadav; Priyansha Gupta; Virendra kumar Mishra; Anju Patel; Mahua Saha; Poonam C. Singh; Pankaj Kumar Srivastava
Microplastics (MPs) are widely acknowledged as emerging pollutants in terrestrial ecosystem, yet their ecological threats in soil remain uncovered. This study presents the first comprehensive assessment of the abundance, characteristics, diversity, and ecological risks of soil-borne MPs across eight distinct landuse types in India, including industrial areas, dumping sites, municipal areas, wetlands, and various agricultural settings. Soil samples were collected and analyzed for MP abundance (MPs kg−1), morphology, polymer composition, diversity assessment and potential environmental risks. The results revealed the highest mean MP abundance in industrial areas (3710 ± 1127), followed by dumping sites (3310 ± 2195), municipal city areas (1247 ± 386), agriculture near dumping sites (546 ± 204), urban agriculture (478 ± 94), agriculture with plastic mulching (210 ± 54), peri-urban agriculture (113 ± 34), and wetlands (63 ± 21). Predominant shapes were fragments, fibers, films, and the particle sizes majorly belonged to 10–300 µm and 300–500 µm. Low-density polyethylene (LDPE), high-density polyethylene (HDPE) and polypropylene (PP) were the most abundant polymers in all the landuses. Shannon-Wiener index (SWI) and Simpson Diversity index (SDI) indicated significant variations in MPs diversity across landuses for shape, size, color, and polymer composition. Landuses were categorized as Level V (>1000) in terms of the Polymer Hazard Index (PHI), while Pollution Load Index (PLI) suggested a minor risk level. Based on the Potential Ecological Risk Index (PERI), wetlands exhibited low-risk and rest other landuses represented low to very high-risk category. The Geo-accumulation Index (Igeo) was also computed and evident as less contaminated landuse (wetland) to extremely contaminated (industrial area) landuse. This study provides baseline data on the occurrence and ecological risk of MPs in Indian soil and highlights the urgent need for targeted mitigation strategies. The findings contribute to a better understanding of MP dynamics across landuses and emphasize the necessity for policy interventions in terrestrial MPs management. © 2025 International Association for Gondwana Research
Re-vitalizing of endophytic microbes for soil health management and plant protection
(Springer Science and Business Media Deutschland GmbH, 2021) Arpan Mukherjee; Shiuly Bhowmick; Shweta Yadav; Md Mahtab Rashid; Gowardhan Kumar Chouhan; Jeetendra Kumar Vaishya; Jay Prakash Verma
Soil health management and increase crop productivity are challenging issues for researchers and scientists. Many research publications have given multiple technological solutions for improving soil health and crop productivity but main problem is sustainability of those technologies under field condition and different agro-climatic zone. Due to the random industrialization, deforestation, mining and other environmental factor reduce soil fertility and human health. Many alternative options e.g., crop rotation, green manuring, integrated farming, biofertilizer (plant-growth-promoting microorganism, microbial consortium of rhizosphere soils), and vermicomposting are available for adapting and improving the soil heath and crop productivity by farmers. Recent trends of new research dimension for sustainable agriculture, endophytic microbes and its consortium is one of the better alternative for increasing crop productivity, soil health and fertility management. However, current trends are focuses on the endophytic microbes, which are present mostly in all plant species. Endophytic microbes are isolated from plant parts—root, shoot, leaf, flower and seeds which have very potential ability of plant growth promotion and bio-controlling agent for enhancing plant growth and development. Mostly plant endophytes showed multi-dimensional (synergistic, mutualistic, symbiotic etc.) interactions within the host plants. It promotes the plant growth, protects from pathogen, and induces resistance against biotic and abiotic environmental stresses, and improves the soil fertility. Till date, most of the scientific research has been done on assuming that interaction of plant endophytes with the host is similar like the plant-growth-promoting microorganism (PGPM). It would be very interesting to explore the functional properties of plant endophytes to modulate the essential gene expression during biotic and abiotic stresses. Endophytes have the ability to induce the soil fertility by improving soil essential nutrient, enzymatic activity and influence the other physiochemical property. In this study, we have discussed details about functional properties of plant endophytes and their mechanism for enhancing plant productivity and soil health and fertility management under climate-resilient agricultural practices. Our main objective is to promote and explore the beneficial plant endophytes for enhancing sustainable agricultural productivity. © 2021, King Abdulaziz City for Science and Technology.
The bioactive potential of phytohormones: A review
(Elsevier B.V., 2022) Arpan Mukherjee; Anand Kumar Gaurav; Saurabh Singh; Shweta Yadav; Shiuly Bhowmick; Saman Abeysinghe; Jay Prakash Verma
Plant hormones play an important role in growth, defence and plants productivity and there are several studies on their effects on plants. However, their role in humans and animals is limitedly studied. Recent studies suggest that plant hormone also works in mammalian systems, and have the potential to reduce human diseases such as cancer, diabetes, and also improve cell growth. Plant hormones such as indole-3-acetic acid (IAA) works as an antitumor, anti-cancer agent, gibberellins help in apoptosis, abscisic acid (ABA) as antidepressant compounds and regulation of glucose homeostasis whereas cytokinin works as an anti-ageing compound. The main aim of this review is to explore and correlate the relation of plant hormones and their important roles in animals, microbes and plants, and their interrelationships, emphasizing mainly human health. The most important and well-known plant hormones e.g., IAA, gibberellins, ABA, cytokinin and ethylene have been selected in this review to explore their effects on humans and animals. © 2022
Unravelling the emerging threats of microplastics to agroecosystems
(Springer Science and Business Media B.V., 2022) Shweta Yadav; Ekta Gupta; Anju Patel; Suchi Srivastava; Virendra Kumar Mishra; Poonam C. Singh; Pankaj Kumar Srivastava; Saroj Kanta Barik
In the past few decades, pollution from microplastics has emerged as an important issue on a global scale. These plastic particles are mainly the result of anthropogenic activities. Urban sprawl, industrialization, indiscriminate use and poor waste management of plastic products are the main factors responsible for the accumulation of microplastics in different ecosystems of the environment. The presence of microplastics in the soil matrix is considered an emerging threat to agroecosystems. Since most of the studies on microplastics have been done in the aquatic environment. The understanding of the ecotoxicological effects of these contaminants in terrestrial ecosystems is still limited, especially in agroecosystems. The negative effects of microplastics on the physical, chemical and biological properties of soil are now revealing. But the effects of microplastics on plant growth and yield are largely unexplored. Microplastic contamination in the soil can alter the functioning of plants by affecting the microbial community of the rhizosphere and disturbing the homeostasis of the agroecosystem. Furthermore, it may transfer into the plant system through nutrient and water absorption channels and affect plant physiology. The pervasive nature of microplastics in the soil is considered a barrier to sustainable agriculture and ecosystem functioning. The present review gives an overview of the sources, dissipation and effects of microplastics with reference to the soil–plant system, highlights the research gaps, and deciphers the possible future threats to agroecosystems. Graphical abstract: [Figure not available: see fulltext.]. © 2022, The Author(s), under exclusive licence to Springer Nature B.V.