Local Mixed-Effects Fitting for Detecting Reproductive Hormone Surge Times

Hormone secretion processes remain part of the biological mystery as they are highly regulated and individual specific. When hormone trajectories from multiple subjects are under investigation, both population-average mechanism and subject-specific deviations are of great interest. In particular, statistical methodologies that enable us not only to identify surge times and surge magnitudes but also to make inference on these biological features is in need. In this paper, we propose a local kernel smoothing method to perform the analysis of multiple hormone curves using the nonparametric mixed-effects model. We develop a local quadratic mixed-effects (LQME) fitting procedure that detects local maxima of the population-average profile curve and the individual profile curves. Related statistical inference is established to carry out a hypothesis test for the local surge and to construct a confidence interval for a detected surge feature. This method is illustrated by simulation studies and a reproductive hormone data analysis.     

C-terminal deletion of AID uncouples class switch recombination from somatic hypermutation and gene conversion

Class-switch recombination (CSR), somatic hypermutation (SHM), and antibody gene conversion are distinct DNA modification reactions, but all are initiated by activation-induced cytidine deaminase (AID), an enzyme that deaminates cytidine residues in single-stranded DNA. Here we describe a mutant form of AID that catalyzes SHM and gene conversion but not CSR. When expressed in E. coli, AID(delta189-198) is more active in catalyzing cytidine deamination than wild-type AID. AID(delta189-198) also promotes high levels of gene conversion and SHM when expressed in eukaryotic cells, but fails to induce CSR. These results underscore an essential role for the C-terminal domain of AID in CSR that is independent of its cytidine deaminase activity and that is not required for either gene conversion or SHM.     

Childhood and Young Adult Overweight/Obesity and Incidence of Depression in the SUN Project

This study included 11,825 participants of a Spanish dynamic prospective cohort based on former students from University of Navarra, registered professionals from some Spanish provinces, and university graduates from other associations, followed‐up for 6.1 years. We aimed to assess the association between childhood or young adult overweight/obesity and the risk of depression. Participants were asked to select which of nine figures most closely represented their body shape at ages 5 and 20 years. Childhood and young adult overweight/obesity was defined as those cases in which participants reported body shape corresponding to the figures 6–9 (more obese categories) at age 5 or 20, respectively. A subject was classified as incident case of depression if he/she was initially free of depression and reported physician‐made diagnosis of depression and/or the use of antidepressant medication in at least one of biannual follow‐up questionnaires. The association between childhood and young adult overweight/obesity and incidence of depression was estimated by multiple‐adjusted hazard ratio (HR) and its 95% confidence interval (95% CI). Overweight/obesity at age 5 years predicted an increased risk for adult depression (HR = 1.50, 95% CI = 1.06–2.12), and a stronger association was observed at age 20 years ((HR = 2.22, 95% CI = 1.22–4.08), (subjects younger than 30 years at recruitment were excluded from this last analysis)). Childhood or young adult overweight/obesity was associated with elevated risk of adult depression. These results, if causal and confirmed in other prospective studies, support treating childhood and young adult overweight/obesity as part of comprehensive adult depression prevention efforts.     

Interactions of an arbuscular mycorrhizal fungus with free or co-encapsulated cells of Rhizobium trifoli and Yarowia lipolytica inoculated into a soil-plant system

Four times higher nodule number was observed when Glomus deserticola (an arbuscular mycorrhizal fungus) was introduced into a soil-plant system as compared to the control inoculated only with Rhizobium trifoli. This symbiotic parameter was further enhanced by Yarowia lipolytica together with an increase in root mycorrhizal infection of about 14%. Soil inoculation with co-encapsulated R. trifoli and Y. lipolytica provoked a 10-fold increase in root nodulation and led to 55% mycorrhization of the test plant.     

16S rRNA gene-based characterization of bacteria potentially associated with phosphate and carbonate precipitation from a granular autotrophic nitrogen removal bioreactor

Applied Microbiology and Biotechnology - A bench-scale granular autotrophic nitrogen removal bioreactor (completely autotrophic nitrogen removal over nitrite (CANON) system) used for the treatment...