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The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike N-terminal domain (NTD) remains poorly characterized despite enrichment of mutations in this region across variants of concern (VOCs). Here, we examine the contribution of the NTD to infection and cell-cell fusion by constructing chimeric spikes bearing B.1.617 lineage (Delta and Kappa variants) NTDs and generating spike pseudotyped lentivirus. We find that the Delta NTD on a Kappa or wild-type (WT) background increases S1/S2 cleavage efficiency and virus entry, specifically in lung cells and airway organoids, through use of TMPRSS2. Delta exhibits increased cell-cell fusogenicity that could be conferred to WT and Kappa spikes by Delta NTD transfer. However, chimeras of Omicron BA.1 and BA.2 spikes with a Delta NTD do not show more efficient TMPRSS2 use or fusogenicity. We conclude that the NTD allosterically modulates S1/S2 cleavage and spike-mediated functions in a spike context-dependent manner, and allosteric interactions may be lost when combining regions from more distantly related VOCs.

The on-campus residence and activities of students, faculty members, visitors, and university staff result in the generation of university campus solid waste (UCSW). An accurate forecast of UCSW generation is crucial for proper on-campus waste management. This chapter, therefore, aims at identifying significant variables that affect the excess production of waste at a higher education institute in Kozhikode in the Indian state of Kerala. The study is expected to improve the waste management program therein. A literature review methodology, along with a series of interviews, has been used to frame and execute a questionnaire-based study where waste management staff provides the required responses. The modeling technique used is a Probit regression. The influential variables that affect the excess generation of waste are average education level, the status of employment, the urban background of most residents, consumption of water and electricity, space understudy, and management control. All the results in this research can be utilized as a part of waste management programs and in improving capacities to manage waste. This will also help in understanding the type of areas that are zones of critical concern in terms of waste management. The observations incorporated in the study is in the Indian context and are unique among the existing literature.