Premature birth and circadian preference in young adulthood: evidence from two birth cohorts

A preference for eveningness (being a “night owl”) and preterm birth (<37 weeks of gestation) are associated with similar adversities, such as elevated blood pressure, impaired glucose regulation, poorer physical fitness, and lower mood. Yet, it remains unclear if and how preterm birth is associated with circadian preference. The aim of this study was to assess this association across the whole gestation range, using both objective and subjective measurements of circadian preference.

Circadian preference was measured among 594 young adults (mean age 24.3 years, SD 1.3) from two cohorts: the ESTER study and the Arvo Ylppö Longitudinal Study. We compared 83 participants born early preterm (<34 weeks) and 165 late preterm (34 to <37 weeks) with those born at term (≥37 weeks, n = 346). We also compared very low birth weight (VLBW, <1500 g) participants with term-born controls. We obtained objective sleep data with actigraphs that were worn for a mean period of 6.8 (SD 1.4) nights. Our primary outcome was sleep midpoint during weekdays and weekend. The sleep midpoint is the half-way time between falling asleep and waking up, and it represents sleep timing. We also investigated subjective chronotype with the Morningness–Eveningness Questionnaire (MEQ) in 688 (n = 138/221/329) ESTER participants. The MEQ consists of 19 questions, which estimates the respondent to be of a “morning”, “evening,” or “intermediate” chronotype, based on the Morningness–Eveningness Score (MES). We analyzed the data from the actigraphs and the MES with three linear regression models, and analyzed distribution of the chronotype class with Pearson χ2.

There were no consistent differences across the study groups in sleep midpoint. As compared with those born at term, the mean differences in minutes:seconds and 95% confidence intervals for the sleep midpoint were: early preterm weekdays 11:47 (?8:34 to 32:08), early preterm weekend 4:14 (?19:45 to 28:13), late preterm weekdays ?10:28 (?26:16 to 5:21), and late preterm weekend ?1:29 (?20:36 to 17:37). There was no difference in sleep timing between VLBW-participants and controls either. The distribution of chronotype in the MEQ among all participants was 12.4% morningness, 65.4% intermediate, and 22.2% eveningness. The distribution of the subjective chronotype class did not differ between the three gestational age groups (p = 0.98). The linear regression models did not show any influence of gestational age group or VLBW status on the MES (all p > 0.5).

We found no consistent differences between adults born early or late preterm and those born at term in circadian preference. The earlier circadian preference previously observed in those born smallest is unlikely to extend across the whole range of preterm birth.     

Vacuole membrane protein 1 marks endoplasmic reticulum subdomains enriched in phospholipid synthesizing enzymes and is required for phosphoinositide distribution

The multispanning membrane protein vacuole membrane protein 1 (VMP1) marks and regulates endoplasmic reticulum (ER)‐domains associated with diverse ER‐organelle membrane contact sites. A proportion of these domains associate with endosomes during their maturation and remodeling. We found that these VMP1 domains are enriched in choline/ethanolamine phosphotransferase and phosphatidylinositol synthase (PIS1), 2 ER enzymes required for the synthesis of various phospholipids. Interestingly, the lack of VMP1 impairs the formation of PIS1‐enriched ER domains, suggesting a role in the distribution of phosphoinositides. In fact, depletion of VMP1 alters the distribution of PtdIns4P and proteins involved in the trafficking of PtdIns4P. Consistently, in these conditions, defects were observed in endosome trafficking and maturation as well as in Golgi morphology. We propose that VMP1 regulates the formation of ER domains enriched in lipid synthesizing enzymes. These domains might be necessary for efficient distribution of PtdIns4P and perhaps other lipid species. These findings, along with previous reports that involved VMP1 in regulating PtdIns3P during autophagy, expand the role of VMP1 in lipid trafficking and explain the pleiotropic effects observed in VMP1‐deficient mammalian cells and other model systems.      

Bare laser‐synthesized Au‐based nanoparticles as nondisturbing surface‐enhanced Raman scattering probes for bacteria identification

The ability of noble metal‐based nanoparticles (NPs) (Au, Ag) to drastically enhance Raman scattering from molecules placed near metal surface, termed as surface‐enhanced Raman scattering (SERS), is widely used for identification of trace amounts of biological materials in biomedical, food safety and security applications. However, conventional NPs synthesized by colloidal chemistry are typically contaminated by nonbiocompatible by‐products (surfactants, anions), which can have negative impacts on many live objects under examination (cells, bacteria) and thus decrease the precision of bioidentification. In this article, we explore novel ultrapure laser‐synthesized Au‐based nanomaterials, including Au NPs and AuSi hybrid nanostructures, as mobile SERS probes in tasks of bacteria detection. We show that these Au‐based nanomaterials can efficiently enhance Raman signals from model R6G molecules, while the enhancement factor depends on the content of Au in NP composition. Profiting from the observed enhancement and purity of laser‐synthesized nanomaterials, we demonstrate successful identification of 2 types of bacteria (Listeria innocua and Escherichia coli). The obtained results promise less disturbing studies of biological systems based on good biocompatibility of contamination‐free laser‐synthesized nanomaterials.

     

Host resistance and pathogen aggressiveness are key determinants of coinfection in the wild

Coinfection, whereby the same host is infected by more than one pathogen strain, may favor faster host exploitation rates as strains compete for the same limited resources. Hence, coinfection is expected to have major consequences for pathogen evolution, virulence, and epidemiology. Theory predicts genetic variation in host resistance and pathogen infectivity to play a key role in how coinfections are formed. The limited number of studies available has demonstrated coinfection to be a common phenomenon, but little is known about how coinfection varies in space, and what its determinants are. Our aim is to understand how variation in host resistance and pathogen infectivity and aggressiveness contribute to how coinfections are formed in the interaction between fungal pathogen Podosphaera plantaginis and Plantago lanceolata. Our phenotyping study reveals that more aggressive strains are more likely to form coinfections than less aggressive strains in the natural populations. In the natural populations most of the variation in coinfection is found at the individual plant level, and results from a common garden study confirm the prevalence of coinfection to vary significantly among host genotypes. These results show that genetic variation in both the host and pathogen populations are key determinants of coinfection in the wild.     

Root fungal colonisations of the understory grass <Emphasis Type="Italic">Deschampsia flexuosa</Emphasis> after top-canopy harvesting

Aims

Root fungal relationships in forest understory may be affected by tree harvesting. Deschampsia flexuosa forms a mutualistic symbiosis with arbuscular mycorrhizal (AM) fungi functioning in nutrient uptake, and a more loose association with dark septate endophytic (DSE) fungi. We asked how harvesting affects fungal colonisations and whether DSE is more prone to change than AM.

Methods

Deschampsia flexuosa plants were sampled close to a control or a cut tree after top-canopy harvesting in a primary successional site. Colonisations were studied using light microscopy. Shoot N%, vegetation cover and soil nutrients were determined.

Results

Tree harvesting did not affect vegetation and soil parameters, except potassium (K⁺) increasing near cut trees. AM colonisation did not change, while DSE increased. Shoot N% increased with increasing DSE near cut trees. Hyaline septate (HSE) hyphae and soil K⁺ and magnesium (Mg²⁺) were positively correlated near control trees. Lichen cover and HSE correlated negatively.

Conclusions

DSE colonisation increased but AM did not change after harvesting. Positive correlation of DSE with shoot N% near cut trees may suggest a role for DSE in favouring plant nitrogen uptake after disturbance in an open microsite. HSE may play a role in K⁺ and Mg²⁺ uptake.

     

Evaluation of different domain-based methods in protein interaction prediction

Protein-protein interactions (PPIs) play an important role in many biological functions. PPIs typically involve binding between domains, the basic units of protein folding, evolution and function. Identifying domain-domain interactions (DDIs) would aid understanding PPI networks. Recently, many computational methods aimed to infer DDIs from databases of interacting proteins and subsequently used the inferred DDIs to predict new PPIs. We attempt to describe systematically current domain-based approaches including the association method, maximum likelihood estimation and parsimonious explanation method. The performance of these methods at inferring DDIs and predicting PPIs was evaluated comparatively. We observe that each method generates artefacts in certain situations and discuss biases in the available benchmark sets.