One of the essential factors the SARS-CoV-2 virus needs to enter a host is a receptor on a human cell — a place where the spike protein can latch onto the cell surface, pierce it and replicate. Without a receptor, there is no replication. Without replication, there is no infection.
Researchers at Princeton University have successfully used a cellular mapping technology called µMap to uncover eight previously unknown entry points of interest for the spike protein, not just ACE2, a molecule identified as the primary viral entry receptor.
What is it: µMap, or micromap, is a proximity labelling technology that identifies protein and enzyme “neighbours” on a cell’s surface. It uses a photocatalyst to flag these spatial relationships by generating a marker that tags molecular neighbours.
The researchers used the spike protein itself as the marker or “antenna” to tag all the receptor sites in the vicinity of ACE2.
The next step: After the technology identified eight novel receptors that interacted with the spike protein, scientists characterised them using a virus pseudoparticle. (A pseudoparticle mimics viral entry but does not carry the genetic material to spread the virus.) They then isolated four entry factors worthy of further investigation.
“The pseudoparticle system allows us to uncouple viral uptake and study the entry process from everything downstream of the infectious cycle,” says Alexander Ploss, a co-author of the study. “So here, we’re basically introducing a reporter gene into the cell and can then quantify how efficiently entry has taken place.”
Implications: Identifying these factors is critical for understanding SARS-Cov-2 pathophysiology and developing new countermeasures.
The research published in September in the Journal of the American Chemical Society (JACS) could expand the arsenal used to fight the virus, particularly as it mutates to evade vaccines.
New research reveals that there was a significant increase in the body mass index (BMI) of children during the pandemic. BMI is a calculation that uses a person’s height and weight to estimate body fat.
The study analysed BMI in mainly Medicaid younger patients in Norfolk, Virginia, two years before and one year after the pandemic began. Medicaid is a government-run health coverage programme serving low-income people in the US.
Data was collected from 238 patients with an average age of 9.47 for females and 9.57 for males. The participants and their parents/guardians were given a questionnaire that looked at six potential sources for lifestyle changes that could affect BMI, including fast food intake and activity levels.
The team discovered an increase in BMI during the study period. Interestingly, the increase was only significant for the female cohort – there was an 11% mean increase in the BMI of girls.
The authors also observed there was a significant correlation between screen time and family time increases during the pandemic and rising paediatric BMIs, as families spent more time at home because of the lockdowns.
“This study reinforces that the health of all communities was negatively impacted by the pandemic, especially lower income and predominantly African-American communities,” John Harrington, one of the senior authors of this study, told ANI.
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Written by: Rakesh Rai, Sushmita Choudhury, Jayanta Kalita, Prabhash K Dutta Research: Rajesh Sharma
