2) The study investigated the infectivity and replication of the Omicron SARS-CoV-2 variant in human colon organoids (mini gut models) derived from multiple donors.
They found that Omicron infection produced higher levels of viral RNA in some donor organoids compared to ...
3) ...the original WA1 strain and Delta variant.
However, Omicron yielded comparable or lower levels of infectious virus particles.
Omicron elicited a weak type I and III interferon response at 24 hours post-infection, which may dampen recognition by immune sensors.
4) However, interferon levels increased at later time points.
Barrier integrity, as measured by transepithelial electrical resistance, was not compromised by any variant.
-Omicron exhibited diminished syncytia formation and less efficient spike protein cleavage ...
5) ...compared to other variants. This could contribute to its reduced fusogenicity and infectious particle production.
In summary, while Omicron replicated effectively in colon organoids, it showed variable infectivity across donors and produced fewer infectious virions ...
6) ...than other variants due to impaired spike processing and cell-cell spread capabilities. This provides insights into Omicron tropism and enteric involvement in COVID-19.
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2) SARS-CoV-2, the virus that causes COVID-19, can infect cells in the gastrointestinal (GI) tract in addition to the lungs. However, it was unclear if infection varies across different regions of the GI tract.
3) The study directly compared SARS-CoV-2 infection of organoid-derived monolayers from the stomach (corpus), small intestine (jejunum), and colon. Jejunal and colonic monolayers were susceptible to SARS-CoV-2 infection, showing viral RNA, proteins ...
2) SARS-CoV-2 spike protein and human ACE2 receptor are both heavily glycosylated. Glycan profiling showed galactosylated glycans were dominant on both.ย
The S1 subunit of spike protein exhibited glycan-binding properties and was able to bind to galactosylated glycans on ACE2 ...
3) Removal of N-glycans significantly reduced the binding of spike protein to ACE2, indicating glycans play an important role in their interaction.
Molecular dynamics simulations suggested specific glycans on ACE2 could interact with glycan recognition domains ...
2) The transmission bottleneck refers to the number of viral particles that initiate an infection in a new host. Past studies have suggested for viruses like influenza and SARS-CoV-2, it usually involves just a few particles.
3) The authors developed mathematical models to simulate the physical process of airborne viral transmission through coughing/breathing. Factors like particle emission/diffusion, evaporation, sedimentation, ventilation and virus inactivation over time were accounted for.
2) The study proposes that latent infection of endothelial cells (ECS) by herpesviruses such as HHV-4 (EBV) and HHV-6 may contribute to the pathophysiology and symptoms of myalgic encephalomyelitis/ chronic fatigue syndrome (ME/ CFS).
3) Herpesviruses are able to infect and establish latency in ECS.
Latent viral proteins can induce EC dysfunction through various mechanisms such as oxidative stress, inflammation, metabolic disruption, etc
2) The study investigated levels of the neurological biomarker neurofilament light chain (NfL) in patients with long COVID who had mild acute COVID-19 and persistent neurocognitive symptoms.
63 patients with long COVID were evaluated 2-30 months after initial COVID-19 infection
3) They underwent neurocognitive tests and had blood samples taken to measure NfL levels.
Levels of NfL were significantly higher in long COVID patients who showed cognitive impairment or fatigue on testing, compared to those without these symptoms.
2) The study investigated whether human leukocyte antigen (HLA) alleles are associated with asymptomatic SARS-CoV-2 infection. HLA genes are involved in immune responses to infections.
Two independent cohorts were analyzed: a US prospective population-based cohort and ...
3) ... an international COVID Human Genetic Effort (CHGE) cohort.
HLA-wide association studies and meta-analyses were performed comparing asymptomatic cases to symptomatic controls with different definitions.