Evolutionary analyses of the gasdermin family suggest conserved roles in infection response despite loss of pore-forming functionality

Background Gasdermins are ancient (>500million-years-ago) proteins, constituting a family of pore-forming proteins that allow the release of intracellular content including proinflammatory cytokines. Despite their importance in the immune response, and although gasdermin and gasdermin-like genes have been identified across a wide range of animal and non-animal species, there is limited information about the evolutionary history of the gasdermin family, and their functional roles after infection. In this study, we assess the lytic functions of different gasdermins across Metazoa species, and use a mouse model of sepsis to evaluate the expression of the different gasdermins during infection. Results We show that the majority of gasdermin family members from distantly related animal clades are pore-forming, in line with the function of the ancestral proto-gasdermin and gasdermin-like proteins of Bacteria. We demonstrate the first expansion of this family occurred through a duplication of the ancestral gasdermin gene which formed gasdermin E and pejvakin prior to the divergence of cartilaginous fish and bony fish ~475 mya. We show that pejvakin from cartilaginous fish and mammals lost the pore-forming functionality and thus its role in cell lysis. We describe that the pore-forming gasdermin A formed ~320 mya as a duplication of gasdermin E prior to the divergence of the Sauropsida clade (the ancestral lineage of reptiles, turtles, and birds) and the Synapsid clade (the ancestral lineage of mammals). We then demonstrate that the gasdermin A gene duplicated to form the rest of the gasdermin family including gasdermins B, C, and D: pore-forming proteins that present a high variation of the exons in the linker sequence, which in turn allows for diverse activation pathways. Finally, we describe expression of murine gasdermin family members in different tissues in a mouse sepsis model, indicating function during infection response. Conclusions In this study we explored the evolutionary history of the gasdermin proteins in animals and demonstrated that the pore-formation functionality has been conserved from the ancient proto-gasdermin protein. We also showed that one gasdermin family member, pejvakin, lost its pore-forming functionality, but that all gasdermin family members, including pejvakin, likely retained a role in inflammation and the physiological response to infection.

Susceptibility of sheep to experimental co-infection with the ancestral lineage of SARS-CoV-2 and its alpha variant

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for a global pandemic that has had significant impacts on human health and economies worldwide. SARS-CoV-2 is highly transmissible and the cause of coronavirus disease 2019 (COVID-19) in humans. A wide range of animal species have also been shown to be susceptible to SARS-CoV-2 infection by experimental and/or natural infections. Domestic and large cats, mink, ferrets, hamsters, deer mice, white-tailed deer, and non-human primates have been shown to be highly susceptible, whereas other species such as mice, dogs, pigs, and cattle appear to be refractory to infection or have very limited susceptibility. Sheep (Ovis aries) are a commonly farmed domestic ruminant that have not previously been thoroughly investigated for their susceptibility to SARS-CoV-2. Therefore, we performed in vitro and in vivo studies which consisted of infection of ruminant-derived cell cultures and experimental challenge of sheep to investigate their susceptibility to SARS-CoV-2. Our results showed that sheep-derived cell cultures support SARS-CoV-2 replication. Furthermore, experimental challenge of sheep demonstrated limited infection with viral RNA shed in nasal and oral swabs primarily at 1-day post challenge (DPC), and also detected in the respiratory tract and lymphoid tissues at 4 and 8 DPC. Sero-reactivity was also observed in some of the principal infected sheep but not the contact sentinels, indicating that transmission to co-mingled naive sheep was not highly efficient; hovewer, viral RNA was detected in some of the respiratory tract tissues of sentinel animals at 21 DPC. Furthermore, we used challenge inoculum consisting of a mixture of two SARS-CoV-2 isolates, representatives of the ancestral lineage A and the B.1.1.7-like alpha variant of concern (VOC), to study competition of the two virus strains. Our results indicate that sheep show low susceptibility to SARS-CoV-2 infection, and that the alpha VOC outcompeted the ancestral lineage A strain.

Associations between SARS-CoV-2 variants and risk of COVID-19 hospitalization among confirmed cases in Washington State: a retrospective cohort study

Background: The COVID–19 pandemic is now dominated by variant lineages; the resulting impact on disease severity remains unclear. Using a retrospective cohort study, we assessed the risk of hospitalization following infection with nine variants of concern or interest (VOC/VOI). Methods: Our study includes individuals with positive SARS–CoV–2 RT PCR in the Washington Disease Reporting System and with available viral genome data, from December 1, 2020 to July 30, 2021. The main analysis was restricted to cases with specimens collected through sentinel surveillance. Using a Cox proportional hazards model with mixed effects, we estimated hazard ratios (HR) for the risk of hospitalization following infection with a VOC/VOI, adjusting for age, sex, and vaccination status. Findings: Of the 27,814 cases, 23,170 (83.3%) were sequenced through sentinel surveillance, of which 726 (3.1%) were hospitalized due to COVID–19. Higher hospitalization risk was found for infections with Gamma (HR 3.17, 95% CI 2.15–4.67), Beta (HR: 2.97, 95% CI 1.65–5.35), Delta (HR: 2.30, 95% CI 1.69–3.15), and Alpha (HR 1.59, 95% CI 1.26–1.99) compared to infections with an ancestral lineage. Following VOC infection, unvaccinated patients show a similar higher hospitalization risk, while vaccinated patients show no significant difference in risk, both when compared to unvaccinated, ancestral lineage cases. Interpretation: Infection with a VOC results in a higher hospitalization risk, with an active vaccination attenuating that risk. Our findings support promoting hospital preparedness, vaccination, and robust genomic surveillance.

Infection and transmission of SARS-CoV-2 and its alpha variant in pregnant white-tailed deer

SARS-CoV-2, a novel Betacoronavirus, was first reported circulating in human populations in December 2019 and has since become a global pandemic. Recent history involving SARS-like coronavirus outbreaks (SARS-CoV and MERS-CoV) have demonstrated the significant role of intermediate and reservoir hosts in viral maintenance and transmission cycles. Evidence of SARS-CoV-2 natural infection and experimental infections of a wide variety of animal species has been demonstrated, and in silico and in vitro studies have indicated that deer are susceptible to SARS-CoV-2 infection. White-tailed deer (Odocoileus virginianus) are amongst the most abundant, densely populated, and geographically widespread wild ruminant species in the United States. Human interaction with white-tailed deer has resulted in the occurrence of disease in human populations in the past. Recently, white-tailed deer fawns were shown to be susceptible to SARS-CoV-2. In the present study, we investigated the susceptibility and transmission of SARS-CoV-2 in adult white-tailed deer. In addition, we examined the competition of two SARS-CoV-2 isolates, representatives of the ancestral lineage A (SARS-CoV-2/human/USA/WA1/2020) and the alpha variant of concern (VOC) B.1.1.7 (SARS-CoV-2/human/USA/CA_CDC_5574/2020), through co-infection of white-tailed deer. Next-generation sequencing was used to determine the presence and transmission of each strain in the co-infected and contact sentinel animals. Our results demonstrate that adult white-tailed deer are highly susceptible to SARS-CoV-2 infection and can transmit the virus through direct contact as well as vertically from doe to fetus. Additionally, we determined that the alpha VOC B.1.1.7 isolate of SARS-CoV-2 outcompetes the ancestral lineage A isolate in white-tailed deer, as demonstrated by the genome of the virus shed from nasal and oral cavities from principal infected and contact animals, and from virus present in tissues of principal infected deer, fetuses and contact animals.

Abstract P884: Differences in Stroke Type and Stroke Risk Factors Between African Americans and Ghanaian Stroke Patients

Introduction: Ancestral lineage of many African Americans (AA) includes West African descent. Previous research has shown a higher prevalence of cardiovascular risk factors such as hypertension and diabetes mellitus (DM) in AA compared to other racial groups in the United States (US). Some have attributed these differences in the US population to ancestral lineage of the AA population. We sought to compare the stroke type and stroke risk factors between AA and Ghana, a country in West Africa. Methods: Data from the UFHealth institutional stroke database and the Kumasi, Ghana Stroke Survivors Registry between 01/2014 and 11/2019 provided a dataset of adult patients diagnosed with stroke from both locations. Multivariate regression analysis identified differences between country of origin, race, stroke type and clinical factors. Results: Among the 5519 patients, the median age was 66 (IQR 45 - 87), 49% woman, 16% AA, 19% Ghanaian, and 66% non-Hispanic white. In the total population, 22% had an intracerebral hemorrhage, 69% ischemic stroke, and 9% subarachnoid hemorrhage. Compared to patients in the U.S., patients from Ghana were younger (OR 1.06, 1.05-1.06 95% CI); more likely female (OR 1.66, 1.0-1.97 95% CI), hypertensive (OR 8.87, 6.46-12.17 95%CI), and more likely to consume alcohol (OR 4.25, 3.32-5.44 95% CI). Ghanaians were less likely to have DM (OR 0.81, 0.66-0.99 95% CI), smoke (OR 0.10, 0.07-0.13 95% CI), and live in an urban vs rural setting (OR 0.84, 0.71-0.99 95% CI). Compared to AA specifically, Ghanaians were younger (OR 1.02, 1.01-1.03 95% CI); more likely female (OR 1.45, 1.15-1.81 95% CI), hypertensive (OR 4.66, 3.25-6.68 95%CI), more likely to consume alcohol (OR 3.68, 2.62-5.18 95% CI); less likely to have DM (OR 0.55, 0.43-0.71 95% CI), smoke (OR 0.13, 0.08-0.19 95% CI), and less likely live in an urban vs rural setting (OR 0.66, 0.53-0.82 95% CI). Conclusion: Significant differences were found between stroke risk factors (hypertension, DM, alcohol consumption, and smoking) and race as well as country of origin. Further study of social and environmental differences between groups may elucidate the differences in stroke risk factors between AA’s and West Africans.

New exon ignites accelerated evolution of placental gene Nrk in the ancestral lineage of eutherians

Accelerated evolution is often driven by the interaction between environmental factors and genes. However, it remains unclear whether accelerated evolution can be ignited. Here, we focused on adaptive events during the emergence of chorioallantoic placenta. We scanned the chromosome X and identified eight accelerated regions in the ancestral lineage of eutherian mammals. Five of these regions (P = 5.61 × 10−11 ~ 9.03 × 10−8) are located in the five exons of Nik-related kinase (Nrk), which is essential in placenta development and fetoplacental induction of labor. Moreover, a eutherian-specific exogenous exon lack of splice variant was found to be conserved. Structure modelling of NRK suggests that the accelerated exons and the eutherian-specific exon could change the enzymatic activity of eutherian NRK. Since the eutherian-specific exon was surrounded by accelerated exons, it indicates that the accelerated evolution of Nrk may be ignited by the emergence of the new exon in the ancestral lineage of eutherian mammals. The new exon might shift the function of Nrk and provide a new fitness landscape for eutherian species to explore. Although multiple exons were accelerated in both of the Nrk catalytic and regulatory domains, positive selection can only be revealed on the regulatory domain if the branch specific nonsynonymous and synonymous rate test was performed by PAML. Thus, it may be important to detect accelerated evolution when studying positive selection on coding regions. Overall, this work suggests that the fundamental process of placental development and fetoplacental induction of labor has been targeted by positive Darwinian selection. Identifying positively selected placental genes provides insights into how eutherian mammals gain benefits from the invasive chorioallantoic placenta to form one of the most successful groups among terrestrial vertebrates.

REBEL KING BHARATH SINGHA AND HIS COINS: BHAUMA-NARAKA LEGEND FOR THE FORMATION OF MATAK KINGDOM

Purpose of the study: Moamaria rebel king Bharath Singha of Assam issued coins declaring himself a descendant of Bhagadatta. In the present study, we have discussed the ancestral lineage of the rebel king and the various aspects of his association of Bhagadatta. Methodology: The ancestral root and genealogy of the Mayamara gurus, the community of the rebel king, based on the biographies and other available sources. Genuine coins issued by Bharath Singha were taken for the present study. Various other primary and secondary sources related to the coinage of Assam, historical events, genealogy, and inscriptions were also analysed, and contents are compared to reach a decision. Main Findings: Bharath Singha established a kingdom based on the Neo-Vaishnavite faith. He associated himself with the legendary king Bhagadatta of Pragjyotishpura for the legitimation of his rule. Applications of this study: The study may be applied in analysing the nature of the Moamaria Rebellion. Novelty/Originality of this study: In the present study we have discussed Moamaria rebel leader Bharath Singha of Assam and his coins. Although a good number of works have been published discussing various aspects of Moamaria Rebellion, no special attention had been given to Bharath Singha.

The role of floral oils in the evolution of apid bees (Hymenoptera: Apidae)

Most bees collect pollen and nectar for their larvae, while some also collect other resources. We investigated the evolution of floral oil-collecting behaviour in the Apidae and the evolutionary effects of floral oils on host brood cells for cuckoo bees. Focusing on apid bee phylogeny, we reconstructed the evolution of floral oil collection by females, use of floral oils in cell construction and the inclusion of oils in provisioning immatures. Ancestral character reconstruction demonstrates that floral oil-collecting behaviour arose four times independently. We also found that in cuckoo bees, parasitization of oil-collecting bees arose three times (including one secondary return) in Apidae. Except for Ctenoplectrina, oil cuckoo bees are all closely related to each other, forming an independent clade within the Nomadinae. Analysis of evolutionary transition rates indicates that there is a greater tendency for switching from an oil-collecting host to a non-oil-collecting host than the reverse. In apid bees, evolutionary transition rates are higher for switching to cuckoo behaviour from an ancestral lineage in which females collect floral oils than from other pollen-collecting lineages. We conclude that adaptation to oil collection is advantageous for pollen-collecting bees, and that the origin of oil cuckoo bees from non-oil cuckoo bees is constrained.