Contrasting heat stress response patterns of coral holobionts across the Red Sea suggest distinct mechanisms of thermal tolerance.

Corals from the northern Red Sea, in particular the Gulf of Aqaba (GoA), have exceptionally high bleaching thresholds approaching >5℃ above their maximum monthly mean (MMM) temperatures. These elevated thresholds are thought to be due to historical selection, as corals passed through the warmer Southern Red Sea during recolonization from the Arabian Sea. To test this hypothesis, we determined thermal tolerance thresholds of GoA versus central Red Sea (CRS) Stylophora pistillata corals using multi-temperature acute thermal stress assays to determine thermal thresholds. Relative thermal thresholds of GoA and CRS corals were indeed similar and exceptionally high (~7℃ above MMM). However, absolute thermal thresholds of CRS corals were on average 3℃ above those of GoA corals. To explore the molecular underpinnings, we determined gene expression and microbiome response of the coral holobiont. Transcriptomic responses differed markedly, with a strong response to the thermal stress in GoA corals and their symbiotic algae versus a remarkably muted response in CRS colonies. Concomitant to this, coral and algal genes showed temperature-induced expression in GoA corals, while exhibiting fixed high expression (front-loading) in CRS corals. Bacterial community composition of GoA corals changed dramatically under heat stress, whereas CRS corals displayed stable assemblages. We interpret the response of GoA corals as that of a resilient population approaching a tipping point in contrast to a pattern of consistently elevated thermal resistance in CRS corals that cannot further attune. Such response differences suggest distinct thermal tolerance mechanisms that may affect the response of coral populations to ocean warming.

How do I facilitate a rapid response to a public health emergency requiring plasma collection with a public-private partnership?

In March 2020, there were no treatment options for COVID-19. Passive immune therapy including anti-SARS-CoV-2 hyperimmune globulin (hIVIG) was a logical candidate for COVID-19 therapeutic trials, given past success treating emerging pathogens with endogenous neutralizing antibodies. We established a plasma collection protocol for persons recovered from COVID-19. To speed recruitment in the first U.S. hotspot, Seattle, Washington, federal and state public health agencies collaborated with Bloodworks Northwest to collect convalescent plasma (CP) for manufacturing hIVIG. During March-December 2020, we identified and recruited prospective CP donors via letters to persons recovered from COVID-19 with laboratory-confirmed SARS-CoV-2 infection. Prospective donors were pre-screened and administered a medical history survey. Anti-SARS-CoV-2 neutralizing antibody (NAb) titers were classified as qualifying (≥1:80) or non-qualifying (<1:80) for enrollment based on a live virus neutralization assay. Generalized estimating equations were used to identify characteristics of donors associated with qualifying versus nonqualifying NAb titers. Overall, 21,359 letters resulted in 3207 inquiries, 2159 prescreenings with laboratory-confirmed SARS-CoV-2 infection, and 573 donors (27% of all pre-screenings with confirmed infection) who provided a screening plasma donation. Of 573 donors screened, 254 (44%) provided plasma with qualifying NAb titers, resulting in 1284 units for hIVIG manufacture. In a multivariable model, after adjusting for other factors, time (60 days) from COVID-19 symptom onset to screening was associated with lower odds of qualifying NAb (adjusted odds ratio = 0.67, 95% CI: 0.48-0.94). The collaboration facilitated a rapid response to develop and provide hIVIG for clinical trials and CP for transfusion. Only 1 in 12 donor inquiries resulted in a qualifying plasma donation. Challenges included recruitment and the relatively low percentage of persons with high NAb titers and limited screening capacity. This resource-intensive collaboration may not be scalable but informs preparedness and response strategies for plasma collection in future epidemics. Operational readiness plans with templates for screening, consent, and data collection forms are recommended.

Six RNA viruses and forty-one hosts: viral small RNAs and modulation of small RNA repertoires in vertebrate and invertebrate systems.

We have used multiplexed high-throughput sequencing to characterize changes in small RNA populations that occur during viral infection in animal cells. Small RNA-based mechanisms such as RNA interference (RNAi) have been shown in plant and invertebrate systems to play a key role in host responses to viral infection. Although homologs of the key RNAi effector pathways are present in mammalian cells, and can launch an RNAi-mediated degradation of experimentally targeted mRNAs, any role for such responses in mammalian host-virus interactions remains to be characterized. Six different viruses were examined in 41 experimentally susceptible and resistant host systems. We identified virus-derived small RNAs (vsRNAs) from all six viruses, with total abundance varying from "vanishingly rare" (less than 0.1% of cellular small RNA) to highly abundant (comparable to abundant micro-RNAs "miRNAs"). In addition to the appearance of vsRNAs during infection, we saw a number of specific changes in host miRNA profiles. For several infection models investigated in more detail, the RNAi and Interferon pathways modulated the abundance of vsRNAs. We also found evidence for populations of vsRNAs that exist as duplexed siRNAs with zero to three nucleotide 3' overhangs. Using populations of cells carrying a Hepatitis C replicon, we observed strand-selective loading of siRNAs onto Argonaute complexes. These experiments define vsRNAs as one possible component of the interplay between animal viruses and their hosts.

The toxic effects of cigarette additives. Philip Morris' project mix reconsidered: an analysis of documents released through litigation.

BACKGROUND: In 2009, the promulgation of US Food and Drug Administration (FDA) tobacco regulation focused attention on cigarette flavor additives. The tobacco industry had prepared for this eventuality by initiating a research program focusing on additive toxicity. The objective of this study was to analyze Philip Morris' Project MIX as a case study of tobacco industry scientific research being positioned strategically to prevent anticipated tobacco control regulations. METHODS AND FINDINGS: We analyzed previously secret tobacco industry documents to identify internal strategies for research on cigarette additives and reanalyzed tobacco industry peer-reviewed published results of this research. We focused on the key group of studies conducted by Phillip Morris in a coordinated effort known as "Project MIX." Documents showed that Project MIX subsumed the study of various combinations of 333 cigarette additives. In addition to multiple internal reports, this work also led to four peer-reviewed publications (published in 2001). These papers concluded that there was no evidence of substantial toxicity attributable to the cigarette additives studied. Internal documents revealed post hoc changes in analytical protocols after initial statistical findings indicated an additive-associated increase in cigarette toxicity as well as increased total particulate matter (TPM) concentrations in additive-modified cigarette smoke. By expressing the data adjusted by TPM concentration, the published papers obscured this underlying toxicity and particulate increase. The animal toxicology results were based on a small number of rats in each experiment, raising the possibility that the failure to detect statistically significant changes in the end points was due to underpowering the experiments rather than lack of a real effect. CONCLUSION: The case study of Project MIX shows tobacco industry scientific research on the use of cigarette additives cannot be taken at face value. The results demonstrate that toxins in cigarette smoke increase substantially when additives are put in cigarettes, including the level of TPM. In particular, regulatory authorities, including the FDA and similar agencies elsewhere, could use the Project MIX data to eliminate the use of these 333 additives (including menthol) from cigarettes.

Control of dengue virus translation and replication.

Dengue poses an increasing threat to public health worldwide. Studies conducted over the past several decades have improved our knowledge of the mechanisms of dengue virus translation and replication. New methodologies have facilitated advances in our understanding of the RNA elements and viral and host factors that modulate dengue virus replication and translation. This review integrates research findings and explores future directions for research into the cellular and molecular mechanisms of dengue virus infection. Lessons learned from dengue virus will inform approaches to other viruses and expand our understanding of the ways in which viruses co-opt host cells during the course of infection. In addition, knowledge about the molecular mechanisms of dengue virus translation and replication and the role of host cell factors in these processes will facilitate development of antiviral strategies.

Implementing the global health security agenda: lessons from global health and security programs.

The Global Health Security Agenda (GHSA) describes a vision for a world that is safe and secure from infectious disease threats; it underscores the importance of developing the international capacity to prevent, detect, and respond to pandemic agents. In February 2014, the United States committed to support the GHSA by expanding and intensifying ongoing efforts across the US government. Implementing these goals will require interagency coordination and harmonization of diverse health security elements. Lessons learned from the Global Health Initiative (GHI), the President's Emergency Program for AIDS Relief (PEPFAR), and the Cooperative Threat Reduction (CTR) program underscore that centralized political, technical, and fiscal authority will be key to developing robust, sustainable, and integrated global health security efforts across the US government. In this article, we review the strengths and challenges of GHI, PEPFAR, and CTR and develop recommendations for implementing a unified US global health security program.

Y box-binding protein-1 binds to the dengue virus 3'-untranslated region and mediates antiviral effects.

Dengue virus, a member of the family Flaviviridae, poses a serious public health threat worldwide. Dengue virus is a positive-sense RNA virus that harbors a genome of approximately 10.7 kb. Replication of dengue virus is mediated coordinately by cis-acting genomic sequences, viral proteins, and host cell factors. We have isolated and identified several host cell factors from baby hamster kidney cell extracts that bind with high specificity and high affinity to sequences within the untranslated regions of the dengue virus genome. Among the factors identified, Y box-binding protein-1 (YB-1) and the heterogeneous nuclear ribonucleoproteins (hnRNPs), hnRNP A1, hnRNP A2/B1, and hnRNP Q, bind to the dengue virus 3'-untranslated region. Further analysis indicated that YB-1 binds to the dengue virus 3' stem loop, a conserved structural feature located at the 3' terminus of the 3'-untranslated region of many flaviviruses. Analysis of the impact of YB-1 on replication of dengue virus in YB-1+/+ and YB-1-/- mouse embryo fibroblasts indicated that host YB-1 mediates an antiviral effect. Further studies demonstrated that this antiviral impact is due, at least in part, to a repressive role of YB-1 on dengue virus translation via a mechanism that requires viral genomic sequences. These results suggest a novel role for YB-1 as an antiviral host cell factor.

Translation efficiency determines differences in cellular infection among dengue virus type 2 strains.

We have investigated the molecular basis for differences in the ability of natural variants of dengue virus type 2 (DEN2) to replicate in primary human cells. The rates of virus binding, virus entry, input strand translation, and RNA stability of low-passage Thai and Nicaraguan and prototype DEN2 strains were compared. All strains exhibited equivalent binding, entry, and uncoating, and displayed comparable stability of positive strand viral RNA over time in primary cells. However, the low-passage Nicaraguan isolates were much less efficient in their ability to translate viral proteins. Sequence analysis of the full-length low-passage Nicaraguan and Thai viral genomes identified specific differences in the 3' untranslated region (3'UTR). Substitution of the different sequences into chimeric RNA reporter constructs demonstrated that the changes in the 3'UTR directly affected the efficiency of viral translation. Thus, differences in infectivity among closely related DEN2 strains correlate with efficiency of translation of input viral RNA.