Phylogenetic patterns of foliar mineral nutrient accumulation among gypsophiles and their relatives in the Chihuahuan Desert

PREMISE OF THE STUDY: Gypsum endemism in plants (gypsophily) is common on gypsum outcrops worldwide, but little is known about the functional ecology of Chihuahuan Desert gypsophiles. We investigated whether leaf chemistry of gypsophile lineages from the northern Chihuahuan Desert are similar to leaves of related nonendemic (gypsovag) species relative to their soil chemistry. We expected widely distributed gypsophiles (hypothesized to be older lineages on gypsum) would have distinct leaf chemistry from narrowly distributed, relatively younger lineages endemic to gypsum and gypsovags, reflecting adaptation to gypsum. METHODS: We collected leaves from 23 gypsophiles and related nonendemic taxa growing on nongypsum soils. Soils and leaves were analyzed for Ca, S, Mg, K, N, and P. Leaf gypsum was assessed using Fourier transform infrared spectroscopy. KEY RESULTS: Most widespread gypsophile lineages that are hypothesized to be relatively old accumulate foliar S, Ca, and gypsum, but younger gypsophile lineages and closely related gypsovags do not. Young, narrowly distributed gypsophile lineages have leaf chemical signatures similar to nonendemic congeners and confamilials. CONCLUSIONS: Our data suggest multiple adaptive mechanisms support life on gypsum in Chihuahuan Desert gypsophiles. Most widespread gypsophiles are specialized for life on gypsum, likely due to shared abilities to accumulate and assimilate S and Ca in leaves. In contrast, narrowly distributed gypsophiles may have mechanisms to exclude excess S and Ca from their leaves, preventing toxicity. Future work will investigate the nutrient accumulation and exclusion patterns of other plant organs to determine at what level excess S and Ca uptake is restricted for young-lineage gypsophiles and gypsovags

Phylogenetic patterns of foliar mineral nutrient accumulation among gypsophiles and their relatives in the Chihuahuan Desert

PREMISE OF THE STUDY: Gypsum endemism in plants (gypsophily) is common on gypsum outcrops worldwide, but little is known about the functional ecology of Chihuahuan Desert gypsophiles. We investigated whether leaf chemistry of gypsophile lineages from the northern Chihuahuan Desert are similar to leaves of related nonendemic (gypsovag) species relative to their soil chemistry. We expected widely distributed gypsophiles (hypothesized to be older lineages on gypsum) would have distinct leaf chemistry from narrowly distributed, relatively younger lineages endemic to gypsum and gypsovags, reflecting adaptation to gypsum. METHODS: We collected leaves from 23 gypsophiles and related nonendemic taxa growing on nongypsum soils. Soils and leaves were analyzed for Ca, S, Mg, K, N, and P. Leaf gypsum was assessed using Fourier transform infrared spectroscopy. KEY RESULTS: Most widespread gypsophile lineages that are hypothesized to be relatively old accumulate foliar S, Ca, and gypsum, but younger gypsophile lineages and closely related gypsovags do not. Young, narrowly distributed gypsophile lineages have leaf chemical signatures similar to nonendemic congeners and confamilials. CONCLUSIONS: Our data suggest multiple adaptive mechanisms support life on gypsum in Chihuahuan Desert gypsophiles. Most widespread gypsophiles are specialized for life on gypsum, likely due to shared abilities to accumulate and assimilate S and Ca in leaves. In contrast, narrowly distributed gypsophiles may have mechanisms to exclude excess S and Ca from their leaves, preventing toxicity. Future work will investigate the nutrient accumulation and exclusion patterns of other plant organs to determine at what level excess S and Ca uptake is restricted for young-lineage gypsophiles and gypsovags

Community seroprevalence of SARS-CoV-2 in children and adolescents in England, 2019-2021

Objective: To understand community seroprevalence of SARS-CoV-2 in children and adolescents. This is vital to understanding the susceptibility of this cohort to COVID-19 and to inform public health policy for disease control such as immunisation. Design: We conducted a community-based cross-sectional seroprevalence study in participants aged 0-18 years old recruiting from seven regions in England between October 2019 and June 2021 and collecting extensive demographic and symptom data. Serum samples were tested for antibodies against SARS-CoV-2 spike and nucleocapsid proteins using Roche assays processed at UK Health Security Agency laboratories. Prevalence estimates were calculated for six time periods and were standardised by age group, ethnicity and National Health Service region. Results: Post-first wave (June-August 2020), the (anti-spike IgG) adjusted seroprevalence was 5.2%, varying from 0.9% (participants 10-14 years old) to 9.5% (participants 5-9 years old). By April-June 2021, this had increased to 19.9%, varying from 13.9% (participants 0-4 years old) to 32.7% (participants 15-18 years old). Minority ethnic groups had higher risk of SARS-CoV-2 seropositivity than white participants (OR 1.4, 95% CI 1.0 to 2.0), after adjusting for sex, age, region, time period, deprivation and urban/rural geography. In children &lt;10 years, there were no symptoms or symptom clusters that reliably predicted seropositivity. Overall, 48% of seropositive participants with complete questionnaire data recalled no symptoms between February 2020 and their study visit. Conclusions: Approximately one-third of participants aged 15-18 years old had evidence of antibodies against SARS-CoV-2 prior to the introduction of widespread vaccination. These data demonstrate that ethnic background is independently associated with risk of SARS-CoV-2 infection in children. Trial registration number: NCT04061382.</p

Serum HCoV-spike specific antibodies do not protect against subsequent SARS-CoV-2 infection in children and adolescents

SARS-CoV-2 infections in children are generally asymptomatic or mild and rarely progress to severe disease and hospitalization. Why this is so remains unclear. Here we explore the potential for protection due to pre-existing cross-reactive seasonal coronavirus antibodies and compare the rate of antibody decline for nucleocapsid and spike protein in serum and oral fluid against SARS-CoV-2 within the pediatric population. No differences in seasonal coronaviruses antibody concentrations were found at baseline between cases and controls, suggesting no protective effect from pre-existing immunity against seasonal coronaviruses. Antibodies against seasonal betacoronaviruses were boosted in response to SARS-CoV-2 infection. In serum, anti-nucleocapsid antibodies fell below the threshold of positivity more quickly than anti-spike protein antibodies. These findings add to our understanding of protection against infection with SARS-CoV-2 within the pediatric population, which is important when considering pediatric SARS-CoV-2 immunization policies