Structural-Dynamics and Binding Analysis of RBD from SARS-CoV-2 Variants of Concern (VOCs) and GRP78 Receptor Revealed Basis for Higher Infectivity.

Glucose-regulated protein 78 (GRP78) might be a receptor for SARS-CoV-2 to bind and enter the host cell. Recently reported mutations in the spike glycoprotein unique to the receptor-binding domain (RBD) of different variants might increase the binding and pathogenesis. However, it is still not known how these mutations affect the binding of RBD to GRP78. The current study provides a structural basis for the binding of GRP78 to the different variants, i.e., B.1.1.7, B.1.351, B.1.617, and P.1 (spike RBD), of SARS-CoV-2 using a biomolecular simulation approach. Docking results showed that the new variants bound stronger than the wild-type, which was further confirmed through the free energy calculation results. All-atom simulation confirmed structural stability, which was consistent with previous results by following the global stability trend. We concluded that the increased binding affinity of the B.1.1.7, B.1.351, and P.1 variants was due to a variation in the bonding network that helped the virus induce a higher infectivity and disease severity. Consequently, we reported that the aforementioned new variants use GRP78 as an alternate receptor to enhance their seriousness.

Occurrence of Campylobacter in retail meat in Lahore, Pakistan.

Campylobacter, one of the emerging zoonotic pathogens, is worldwide in distribution. This thermo-tolerant pathogen is one of the leading causes of diarrhea and gastroenteritis in humans. The main sources of infection are contaminated meat and meat products. A cross-sectional study was conducted to estimate the prevalence of Campylobacter species in retail meat in the Lahore district of Pakistan from September 2014 to January 2015. A total of 600 samples (200 samples each of beef, mutton, and chicken) were collected from retail shops through convenience sampling and preceded for Campylobacter contamination using the ISO 10272-1:2006 (E) method. Campylobacter was present in all three types of meat; the highest prevalence being recorded in chicken meat (29%) followed by mutton (18%) and beef (15.5%). Campylobacters were isolated from 125 (20.8%) samples out of the 600 meat samples. Campylobacter jejuni was more common (74.4%) than C. coli (25.6%). The highest number of Campylobacters were isolated in September (25/125) and November (23/125) while low numbers were isolated in October and December with isolates rate of (17/125) and (19/125), respectively. The highest prevalence was seen in the oldest and overpopulated town of Data Gunj Bakhsh 16% (20/125) while lowest prevalence was seen in a newer and least populated town of Gulburg (7/125). These results indicate that Campylobacter species are circulating in various meat sources in Lahore and that it may pose a threat to public health.