Grass leaves as potential hominin dietary resources

Discussions about early hominin diets have generally excluded grass leaves as a staple food resource, despite their ubiquity in most early hominin habitats. In particular, stable carbon isotope studies have shown a prevalent C4 component in the diets of most taxa, and grass leaves are the single most abundant C4 resource in African savannas. Grass leaves are typically portrayed as having little nutritional value (e.g., low in protein and high in fiber) for hominins lacking specialized digestive systems. It has also been argued that they present mechanical challenges (i.e., high toughness) for hominins with bunodont dentition. Here, we compare the nutritional and mechanical properties of grass leaves with the plants growing alongside them in African savanna habitats. We also compare grass leaves to the leaves consumed by other hominoids and demonstrate that many, though by no means all, compare favorably with the nutritional and mechanical properties of known primate foods. Our data reveal that grass leaves exhibit tremendous variation and suggest that future reconstructions of hominin dietary ecology take a more nuanced approach when considering grass leaves as a potential hominin dietary resource.Horizon 2020(H2020)ERC-STG 677576Bioarchaeolog

Tales of diversity: Genomic and morphological characteristics of forty-six <i>Arthrobacter</i> phages

<div><p>The vast bacteriophage population harbors an immense reservoir of genetic information. Almost 2000 phage genomes have been sequenced from phages infecting hosts in the phylum Actinobacteria, and analysis of these genomes reveals substantial diversity, pervasive mosaicism, and novel mechanisms for phage replication and lysogeny. Here, we describe the isolation and genomic characterization of 46 phages from environmental samples at various geographic locations in the U.S. infecting a single <i>Arthrobacter</i> sp. strain. These phages include representatives of all three virion morphologies, and Jasmine is the first sequenced podovirus of an actinobacterial host. The phages also span considerable sequence diversity, and can be grouped into 10 clusters according to their nucleotide diversity, and two singletons each with no close relatives. However, the clusters/singletons appear to be genomically well separated from each other, and relatively few genes are shared between clusters. Genome size varies from among the smallest of siphoviral phages (15,319 bp) to over 70 kbp, and G+C contents range from 45–68%, compared to 63.4% for the host genome. Although temperate phages are common among other actinobacterial hosts, these <i>Arthrobacter</i> phages are primarily lytic, and only the singleton Galaxy is likely temperate.</p></div

Risk of COVID-19 after natural infection or vaccinationResearch in context

Summary: Background: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. Methods: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7–15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. Findings: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05–0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01–0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. Interpretation: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. Funding: National Institutes of Health

Genome organization of <i>Arthrobacter</i> phage Laroye, Cluster AL.

<p>See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180517#pone.0180517.g005" target="_blank">Fig 5</a> for details.</p

Genome organization of <i>Arthrobacter</i> phage Gordon, Cluster AU.

<p>See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180517#pone.0180517.g005" target="_blank">Fig 5</a> for details.</p

Genome organization of <i>Arthrobacter</i> phage Maggie, Cluster AN.

<p>See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180517#pone.0180517.g005" target="_blank">Fig 5</a> for details.</p

Genome organization of <i>Arthrobacter</i> phage Amigo, Cluster AQ.

<p>See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180517#pone.0180517.g005" target="_blank">Fig 5</a> for details.</p

Genome organization of <i>Arthrobacter</i> phage Korra, Cluster AK.

<p>The genome of <i>Arthrobacter</i> phage Korra is shown with predicted genes depicted as boxes either above (rightwards-expressed) or below (leftwards-expressed) the genome. Genes are colored according to the phamily designations using Phamerator and database Actinobacteriophage_692, with the phamily number shown above each gene with the number of phamily members in parentheses.</p