SARS-CoV-2 B.1.617.2 Delta variant replication and immune evasion

Abstract: The B.1.617.2 (Delta) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first identified in the state of Maharashtra in late 2020 and spread throughout India, outcompeting pre-existing lineages including B.1.617.1 (Kappa) and B.1.1.7 (Alpha)1. In vitro, B.1.617.2 is sixfold less sensitive to serum neutralizing antibodies from recovered individuals, and eightfold less sensitive to vaccine-elicited antibodies, compared with wild-type Wuhan-1 bearing D614G. Serum neutralizing titres against B.1.617.2 were lower in ChAdOx1 vaccinees than in BNT162b2 vaccinees. B.1.617.2 spike pseudotyped viruses exhibited compromised sensitivity to monoclonal antibodies to the receptor-binding domain and the amino-terminal domain. B.1.617.2 demonstrated higher replication efficiency than B.1.1.7 in both airway organoid and human airway epithelial systems, associated with B.1.617.2 spike being in a predominantly cleaved state compared with B.1.1.7 spike. The B.1.617.2 spike protein was able to mediate highly efficient syncytium formation that was less sensitive to inhibition by neutralizing antibody, compared with that of wild-type spike. We also observed that B.1.617.2 had higher replication and spike-mediated entry than B.1.617.1, potentially explaining the B.1.617.2 dominance. In an analysis of more than 130 SARS-CoV-2-infected health care workers across three centres in India during a period of mixed lineage circulation, we observed reduced ChAdOx1 vaccine effectiveness against B.1.617.2 relative to non-B.1.617.2, with the caveat of possible residual confounding. Compromised vaccine efficacy against the highly fit and immune-evasive B.1.617.2 Delta variant warrants continued infection control measures in the post-vaccination era

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Abiotic and Biotic Stress in Plants - Recent Advances and Future Perspectives

The impact of global climate change on crop production has emerged as a major research priority during the past decade. Understanding abiotic stress factors such as temperature and drought tolerance and biotic stress tolerance traits such as insect pest and pathogen resistance in combination with high yield in plants is of paramount importance to counter climate change related adverse effects on the productivity of crops. In this multi-authored book, we present synthesis of information for developing strategies to combat plant stress. Our effort here is to present a judicious mixture of basic as well as applied research outlooks so as to interest workers in all areas of plant science. We trust that the information covered in this book would bridge the much-researched area of stress in plants with the much-needed information for evolving climate-ready crop cultivars to ensure food security in the future

Climate Resilient Agriculture - Strategies and Perspectives

The changing climatic scenario has affected crop production in the adverse ways, and the impact of it on agriculture is now emerging as a major priority among crop science researchers. Agriculture in this changing climatic scenario faces multiple diverse challenges due to a wide array of demands. Climate-resilient agriculture is the need of the hour in many parts of the world. Understanding the adverse effects of climatic change on crop growth and development and developing strategies to counter these effects are of paramount importance for a sustainable climate-resilient agriculture. This multiauthored edited book brings out sound climate-resilient agriculture strategies that have a strong basic research foundation. We have attempted to bridge information from various diverse agricultural disciplines, such as soil science, agronomy, plant breeding, and plant protection, which can be used to evolve a need-based technology to combat the climatic change in agriculture

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Not AvailableRice paddies have complex trophic food webs of flora and fauna. Integrated biodiversity management of flowering forbs can help conserve the beneficial insects of rice ecosystem, in turn enhancing natural biological control of pests. A concept of habitat management through ecological engineering has been developed at the ICAR - Indian Institute of Rice Research, tested, and validated in farmers’ fields over several seasons of crop. The strategies are low cost, easy to adopt, ecological sound and environmentally friendly, while providing farmers with monetary returns and nutritional benefits. One of the techniques advocated, is increasing floral diversity. Floral diversity can be maintained by conserving commonly occurring flowering forbs in rice fields or by growing a crop plant that provides monetary and nutritional benefits. Flowering plants on rice bunds had significant impact on biodiversity of parasitoids such as Anagrus, Oligosita and others. Field studies through baiting and laboratory studies for longevity indicated enhanced parasitization rates and six to ten times increase in longevity of parasitoids. Significant differences were observed in parasitism of hopper eggs in plots with different crop borders in comparison to plots without flower borders (F= 4.91; df 7; p <0.01).Not Availabl

Crop Stress and its Management: Perspectives and Strategies

XVI, 612 p.online resource

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Not AvailableAmphiareus constrictus (Stal.) an anthocorid predator has been reported to feed on the brown planthopper Nilaparvata lugens Stal., a key pest of rice. Recently, the mass rearing of this predator has been standardized, offering scope for its utilization in applied biological control. Therefore a study was taken up to compare the life cycle and biology of the predator on its factitious host, Corcyra cepahlonica Stainton and the brown plant hopper in order to assess its potential for pest management. The total nymphal duration of A. constrictus when fed a diet of BPH eggs was observed to be 15.5 ± 0.35 days with a survival of 73.33 - 100 % for various instars. The biological parameters did not differ significantly from its factitious host Corcyra, indicating that it is a potential candidate for biological control.Not Availabl

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Not AvailableRice pests viz., stem borer and leaf folder are major biotic constraints for rice production. Bio-intensive pest management (BIPM) is the way forward to reduce the pesticide usage and conservation of beneficial insect biodiversity which in turn enhances the natural control. In order to assess the impact of BIPM practices on the incidence of pests and their natural control, the present study was conducted during kharif- 2020. The BIPM practices included, application of farm yard manure; rice husk ash; wet seed treatment with Pseudomonas fluorescens, Trichoderma harzianum IIRR strain and Bacillus subtilis IIRR strain; clipping of seedlings; alley ways and foliar application of bio-agents. Fortnightly observations were taken by visual counts. The natural enemies count per quadrat of braconids (8.50-9.50), dryinids (5.25-6.25), ichneumonids (1.00-1.25), predatory ants (3.50-5.50), carabids (2.00-4.50), dragonflies (1.00-1.75), damselflies (2.00-2.75), tettigonids (1.00), tetragnathids (28-42) and lycosids (35.00-36.50) was significantly higher in BIPM treatments and least in farmer’s practice plots. The diseased leaf folder larvae were highest in untreated control (9.50 per quadrat), followed by BIPM 1 (7.25 per quadrat) and least in farmer’s practice 2 (2.50 per quadrat). BIPM 3 recorded highest yield of 8475 Kg/ ha, followed by BIPM 1 (8275 Kg/ ha), farmer’s practice 1 (7825 Kg/ ha), BIPM 2 (7750 kg/ ha), untreated control (7250 Kg/ ha) and farmer’s practice 2 (7050 Kg/ ha). BIPM practices had a good impact on improving the yields and enhancing the mortality rate of leaf folder through improving predator, parasitoid and entomopathogenic fungi densities.Not Availabl

How manufacturing processes affect the level of pesticide residues in tea†

Tea (both green and black) is consumed throughout the world, both for pleasure and therapeutic purposes. Most people will be unaware of their involuntary exposure to residues of pesticides lingering in processed tea and so possibly transferring into infusions of tea. The purpose of this work was to study the effect of green tea and orthodox black tea manufacturing processes on the fate of pesticides sprayed onto tea bushes (Camellia sinensis). The fates of residues of dimethoate, quinalphos, dicofol and deltamethrin in these two different types of tea manufacturing processes were compared. For black tea, the manufacturing process involves leaf harvesting, withering, rolling, fermentation and drying; and for green tea, leaf harvesting, microwave heating, rolling and drying. The two processes resulted in the same concentration factor of plant material into the dried commodity, while the decreases in residue levels were different for different pesticides. Initial microwave heating and dehydration in the green tea manufacturing process resulted in greater loss of pesticide residues than did withering and dehydration in black tea; no significant reduction in residue level resulted from the rolling and fermentation steps in black tea. Residue levels in both green and black teas were reduced during final drying. 2004 Society of Chemical Industr