Divergence together with microbes: A comparative study of the associated microbiomes in the closely related Littorina species

Any multicellular organism during its life is involved in relatively stable interactions with microorganisms. The organism and its microbiome make up a holobiont, possessing a unique set of characteristics and evolving as a whole system. This study aimed to evaluate the degree of the conservativeness of microbiomes associated with intertidal gastropods. We studied the composition and the geographic and phylogenetic variability of the gut and body surface microbiomes of five closely related sympatric Littorina (Neritrema) spp. and a more distant species, L. littorea, from the sister subgenus Littorina (Littorina). Although snail-associated microbiomes included many lineages (207–603), they were dominated by a small number of OTUs of the genera Psychromonas, Vibrio, and Psychrilyobacter. The geographic variability was greater than the interspecific differences at the same collection site. While the microbiomes of the six Littorina spp. did not differ at the high taxonomic level, the OTU composition differed between groups of cryptic species and subgenera. A few species-specific OTUs were detected within the collection sites; notably, such OTUs never dominated microbiomes. We conclude that the composition of the high-rank taxa of the associated microbiome (“scaffolding enterotype”) is more evolutionarily conserved than the composition of the low-rank individual OTUs, which may be site- and / or species-specific.

Estimating area-level variation in SARS-CoV-2 infection fatality ratios

BackgroundDuring a pandemic, estimates of geographic variability in disease burden are important but limited by the availability and quality of data.MethodsWe propose a framework for estimating geographic variability in testing effort, total number of infections, and infection fatality ratio (IFR). Because symptomatic people are more likely to seek testing, we use a noncentral hypergeometric model that accounts for differential probability of positive tests. We apply this framework to the United States (U.S.) COVID-19 pandemic to estimate county-level SARS-CoV-2 IFRs from March 1, 2020 to October 31, 2020. Using data on population size, number of observed cases, number of reported deaths in each U.S. county and state, and number of tests in each U.S. state, we develop a series of estimators to identify the number of SARS-CoV-2 infections and IFRs at the county level. We then perform a simulation and compare the estimated values to simulated values to demonstrate the validity of our approach.FindingsApplying the county-level estimators to the real, unsimulated COVID-19 data spanning March 1, 2020 to October 31, 2020 from across the U.S., we found that IFRs varied from 0 to 0.0273, with an interquartile range of 0.0022 and a median of 0.0018. The estimators for IFRs, number of infections, and number of tests showed high accuracy and precision; for instance, when applied to simulated validation data sets, across counties, Pearson correlation coefficients between estimator means and true values were 0.88, 0.95, and 0.74, respectively.InterpretationWe propose an estimation framework that can be used to identify area-level variation in IFRs and performs well to estimate county-level IFRs in the U.S. COVID-19 pandemic.

DIVERSITY AND PHENOTYPIC STRUCTURE OF POPULATIONS OF EUROPEAN SPRUCE (PICEA ABIES) IN THE EAST OF THE RANGE

European spruce ( Picea abies (L.) Karst.) is widespread in Europe. It is of interest to study its biological characteristics in the eastern part of the range, where it transforms into an intermediate form with Siberian spruce. Phenotypic traits of spruce in this area have so far been studied mainly by visual and descriptive techniques. The aim of the study is to study the variability of the main systematic characters, diversity and phenotypic structure of European spruce in the east of the range using mathematical and statistical techniques. This approach made it possible to objectively assess the parameters of its systematic characters, their relationship, and also to identify three significantly different groups of populations. It is shown that in this area the average length of spruce cones is in the range from 80-85 to 100-114 mm. The coefficient of narrowing of the upper part of the seed scales ( C ) is 25-35%, the coefficient of projection ( C ) is 60-80%, their difference ( C- C ) is -25… -55%. The value of the individual variation in the length of cones and the C index is 12-15%, C index is about 20%, and C-C is 30-35%. The intrapopulation coefficient of negative correlation of C and C indices has an average level (-0.3…-0.6). Their correlation between populations is much higher (-0.9). In the geographic variability of indicators of the shape of seed scales and the length of the cones, there is a correlation of the average level. The frequency of individuals of European spruce phenotypes in the populations of the groups P. ab, P. ab×ab×m., P. ab×m., Distinguished by the metric parameters of seed scales, is 98-100, 85-95, 57-70%, respectively. The research results can be useful for forestry and in substantiating the identified intraspecific taxa.

The stratification maxima of the seasonally varying Surface layer in the Arctic Ocean’s Beaufort Gyre

The Beaufort Gyre region of the Arctic Ocean is strongly stratified at the base of the wintertime mixed layer, which impedes the vertical transport of heat, energy, and other tracers. Ice-Tethered Profiler observations during 2004-2018 were used to characterize and investigate the seasonal and interannual variability of the strength, depth, density, and thickness of this highly stratified layer at the base of the mixed layer. This includes investigating the remnant stratification maximum, which formed when the summer mixed layer shoaled. Seasonally, the stratification maximum was never in a steady state. It was largest in October (4.8 × 10−3 rad2/sec2) and decreased during all winter months (to 2.3 × 10−3rad2/sec2 in June), indicating that surface forcing and interior vertical mixing were never in equilibrium during the year. Interannually, the period from 2011-2018 had a higher stratification maximum than then the period from 2005-2010 regardless of the season. The remnant stratification maximum was consistently weaker than the winter stratification maximum from which it formed. The initial evolution of the remnant stratification maximum is used to estimate an effective vertical diffusivity of order 10−6m2/s. No significant geographic variability was found, in part due to high temporal and small scale variability of the stratification maximum layer. Implications for heat transport through to the sea ice cover are discussed.

Natural Products from Tongan Marine Organisms

The islands of the South Pacific Ocean have been in the limelight for natural product biodiscovery, due to their unique and pristine tropical waters and environment. The Kingdom of Tonga is an archipelago in the central Indo-Pacific Ocean, consisting of 176 islands, 36 of which are inhabited, flourishing with a rich diversity of flora and fauna. Many unique natural products with interesting bioactivities have been reported from Indo-Pacific marine sponges and other invertebrate phyla; however, there have not been any reviews published to date specifically regarding natural products from Tongan marine organisms. This review covers both known and new/novel Marine Natural Products (MNPs) and their biological activities reported from organisms collected within Tongan territorial waters up to December 2020, and includes 109 MNPs in total, the majority from the phylum Porifera. The significant biological activity of these metabolites was dominated by cytotoxicity and, by reviewing these natural products, it is apparent that the bulk of the new and interesting biologically active compounds were from organisms collected from one particular island, emphasizing the geographic variability in the chemistry between these organisms collected at different locations.

Geographic variability of antibiotic prescribing for acute respiratory tract infections within a direct-to-consumer telemedicine practice

In this retrospective cohort study of patients presenting to a national direct-to-consumer medical practice, we found that provider geographic location is a stronger driver of antibiotic prescribing than patient location. Physicians in the Northeast and South are significantly more likely than physicians in the West to prescribe antibiotics for upper respiratory infection and bronchitis.