The signature of long-standing balancing selection at the human defensin β-1 promoter

Background  

Defensins, small endogenous peptides with antimicrobial activity, are pivotal components of the innate immune response. A large cluster of defensin genes is located on human chromosome 8p; among them the beta defensin 1 (DEFB1) promoterhas been extensively studied since discovery that specific polymorphisms and haplotypes associate with asthma and atopy, susceptibility to severe sepsis, as well as HIV and Candida infection predisposition.     

Nuclear Stress-Strain State over Micropillars: A Mechanical <i>In silico</i> Study

Cells adapt to their environment and stimuli of different origin. During confined migration through sub-cellular and sub-nuclear pores, they can undergo large strains and the nucleus, the most voluminous and the stiffest organelle, plays a critical role. Recently, patterned microfluidic devices have been employed to analyze the cell mechanical behavior and the nucleus self-deformations. In this paper, we present an in silico model to simulate the interactions between the cell and the underneath microstructured substrate under the effect of the sole gravity. The model lays on mechanical features only and it has the potential to assess the contribution of the nuclear mechanics on the cell global behavior. The cell is constituted by the membrane, the cytosol, the lamina, and the nucleoplasm. Each organelle is described through a constitutive law defined by specific mechanical parameters, and it is composed of a fluid and a solid phase leading to a viscoelastic behavior. Our main objective is to evaluate the influence of such mechanical components on the nucleus behavior. We have quantified the stress and strain distributions in the nucleus, which could be responsible of specific phenomena such as the lamina rupture or the expression of stretch-sensitive proteins.     

Risk assessment does not explain high prevalence of gestational diabetes mellitus in a large group of Sardinian women

Background  

A very high prevalence (22.3%) of gestational diabetes mellitus (GDM) was recently reported following our study on a large group of Sardinian women. In order to explain such a high prevalence we sought to characterise our obstetric population through the analysis of risk factors and their association with the development of GDM.     

The Bay of Bengal exposes abundant photosynthetic picoplankton and newfound diversity along salinity-driven gradients

The Bay of Bengal (BoB) is a 2,600,000 km² expanse in the Indian Ocean upon which many humans rely. However, the primary producers underpinning food chains here remain poorly characterized. We examined phytoplankton abundance and diversity along strong BoB latitudinal and vertical salinity gradients—which have low temperature variation (27–29°C) between the surface and subsurface chlorophyll maximum (SCM). In surface waters, Prochlorococcus averaged 11.7 ± 4.4 × 10⁴ cells ml⁻¹, predominantly HLII, whereas LLII and ‘rare’ ecotypes, HLVI and LLVII, dominated in the SCM. Synechococcus averaged 8.4 ± 2.3 × 10⁴ cells ml⁻¹ in the surface, declined rapidly with depth, and population structure of dominant Clade II differed between surface and SCM; Clade X was notable at both depths. Across all sites, Ostreococcus Clade OII dominated SCM eukaryotes whereas communities differentiated strongly moving from Arabian Sea-influenced high salinity (southerly; prasinophytes) to freshwater-influenced low salinity (northerly; stramenopiles, specifically, diatoms, pelagophytes, and dictyochophytes, plus the prasinophyte Micromonas) surface waters. Eukaryotic phytoplankton peaked in the south (1.9 × 10⁴ cells ml⁻¹, surface) where a novel Ostreococcus was revealed, named here Ostreococcus bengalensis. We expose dominance of a single picoeukaryote and hitherto ‘rare’ picocyanobacteria at depth in this complex ecosystem where studies suggest picoplankton are replacing larger phytoplankton due to climate change.