The association between age and telomere length is age‐dependent: Evidence for a threshold model of telomere length maintenance

This is the final version. Available on open access from Wiley via the DOI in this record. Data availability statement: The data that supports the findings of this study are available in the Supporting Information material of this articleTelomere length and dynamics are commonly used biomarkers of somatic state, yet the role of telomeres underlying the aging process is still debated. Indeed, to date, empirical evidence for an association between age and telomere length is mixed. Here, we test if the age‐dependency of the association between age and telomere length can provide a potential explanation for the reported inconsistencies across studies. To this end, we quantified telomere length by telomere restriction fragment analysis in two groups of Japanese quail (Coturnix japonica) that differed in their age distribution. One group consisted of young adults only, whereas the second group consisted of adults across a wide range of ages. In the young adults group, there was a highly significant negative association between telomere length and age, whereas no association between age and telomere length was found in the all‐ages adults group. This difference between groups was not due to telomere length‐dependent selective disappearance. Our results shows that the association between telomere length and age is age‐dependent and suggest that the costs and benefits associated with telomere maintenance are dynamic across an individual's life course.European Union Horizon 2020Swiss National Science FoundationUniversity of Castilla‐ La ManchaThe Company of Biologists limite

Reproductive strategies affect telomere dynamics across the life course

This is the author accepted manuscript. The final version is available from University of Chicago Press via the DOI in this record Data accessibility: All data and code associated with this article are available in the Dryad Digital Repository doi: 10.5061/dryad.h44j0zpk0Because parental care has a heritable basis, the benefits of receiving increased parental provisioning early in life are genetically linked to the costs of providing increased parental provisioning at adulthood. Reproductive strategies thus result in distinct cost-benefit syndromes across the life course that may shape individual health and ageing trajectories. Here we used an artificial selection approach in Japanese quail (Coturnix japonica) to test how reproductive strategies affect telomere length, a biomarker of somatic state, at different life stages. We show that males, but not females, from lines selected for low maternal investment (i.e. developing in a relatively small egg) had shorter telomeres at birth. These patterns were still weakly present at the end of the juvenile growth period. In contrast, significantly shorter telomeres were found in reproductively active adult birds from the high investment lines, suggesting that telomere attrition was accelerated in these individuals once they had become reproductively active. Our study shows that reproductive strategies differentially affect telomere dynamics across the life course, highlighting the role of cross-generational constraints in shaping individual ageing trajectories.European CommissionSwiss National Science Foundatio

Designing libraries of chimeric proteins using SCHEMA recombination and RASPP

SCHEMA is a method for designing libraries of novel proteins by recombination of homologous sequences. The goal is to maximize the number of folded proteins while simultaneously generating significant sequence diversity. Here, we use the RASPP algorithm to identify optimal SCHEMA designs for shuffling contiguous elements of sequence. To exemplify the method, SCHEMA is used to recombine five fungal cellobiohydrolases (CBH1s) to produce a library of more than 390,000 novel CBH1 sequences

The Drosophila Anion Exchanger (DAE) lacks a detectable interaction with the spectrin cytoskeleton

<p>Abstract</p> <p>Background</p> <p>Current models suggest that the spectrin cytoskeleton stabilizes interacting ion transport proteins at the plasma membrane. The human erythrocyte anion exchanger (AE1) was the first membrane transport protein found to be associated with the spectrin cytoskeleton. Here we evaluated a conserved anion exchanger from Drosophila (DAE) as a marker for studies of the downstream effects of spectrin cytoskeleton mutations.</p> <p>Results</p> <p>Sequence comparisons established that DAE belongs to the SLC4A1-3 subfamily of anion exchangers that includes human AE1. Striking sequence conservation was observed in the C-terminal membrane transport domain and parts of the N-terminal cytoplasmic domain, but not in the proposed ankyrin-binding site. Using an antibody raised against DAE and a recombinant transgene expressed in <it>Drosophila </it>S2 cells DAE was shown to be a 136 kd plasma membrane protein. A major site of expression was found in the stomach acid-secreting region of the larval midgut. DAE codistributed with an infolded subcompartment of the basal plasma membrane of interstitial cells. However, spectrin did not codistribute with DAE at this site or in anterior midgut cells that abundantly expressed both spectrin and DAE. Ubiquitous knockdown of DAE with dsRNA eliminated antibody staining and was lethal, indicating that DAE is an essential gene product in <it>Drosophila</it>.</p> <p>Conclusions</p> <p>Based on the lack of colocalization and the lack of sequence conservation at the ankyrin-binding site, it appears that the well-characterized interaction between AE1 and the spectrin cytoskeleton in erythrocytes is not conserved in <it>Drosophila</it>. The results establish a pattern in which most of the known interactions between the spectrin cytoskeleton and the plasma membrane in mammals do not appear to be conserved in <it>Drosophila</it>.</p

Bed bug deterrence

A recent study in BMC Biology has determined that the immature stage of the bed bug (the nymph) signals its reproductive status to adult males using pheromones and thus avoids the trauma associated with copulation in this species. The success of this nymphal strategy of deterrence is instructive. Against the background of increasing problems with bed bugs, this research raises the question whether pheromones might be used to control them

Cross-sectional associations between sleep duration, sedentary time, physical activity, and adiposity indicators among Canadian preschool-aged children using compositional analyses

Abstract Background Sleep duration, sedentary behaviour, and physical activity are three co-dependent behaviours that fall on the movement/non-movement intensity continuum. Compositional data analyses provide an appropriate method for analyzing the association between co-dependent movement behaviour data and health indicators. The objectives of this study were to examine: (1) the combined associations of the composition of time spent in sleep, sedentary behaviour, light-intensity physical activity (LPA), and moderate- to vigorous-intensity physical activity (MVPA) with adiposity indicators; and (2) the association of the time spent in sleep, sedentary behaviour, LPA, or MVPA with adiposity indicators relative to the time spent in the other behaviours in a representative sample of Canadian preschool-aged children. Methods Participants were 552 children aged 3 to 4 years from cycles 2 and 3 of the Canadian Health Measures Survey. Sedentary time, LPA, and MVPA were measured with Actical accelerometers (Philips Respironics, Bend, OR USA), and sleep duration was parental reported. Adiposity indicators included waist circumference (WC) and body mass index (BMI) z-scores based on World Health Organization growth standards. Compositional data analyses were used to examine the cross-sectional associations. Results The composition of movement behaviours was significantly associated with BMI z-scores (p = 0.006) but not with WC (p = 0.718). Further, the time spent in sleep (BMI z-score: γ sleep  = −0.72; p = 0.138; WC: γ sleep  = −1.95; p = 0.285), sedentary behaviour (BMI z-score: γ SB  = 0.19; p = 0.624; WC: γ SB  = 0.87; p = 0.614), LPA (BMI z-score: γ LPA  = 0.62; p = 0.213, WC: γ LPA  = 0.23; p = 0.902), or MVPA (BMI z-score: γ MVPA  = −0.09; p = 0.733, WC: γ MVPA  = 0.08; p = 0.288) relative to the other behaviours was not significantly associated with the adiposity indicators. Conclusions This study is the first to use compositional analyses when examining associations of co-dependent sleep duration, sedentary time, and physical activity behaviours with adiposity indicators in preschool-aged children. The overall composition of movement behaviours appears important for healthy BMI z-scores in preschool-aged children. Future research is needed to determine the optimal movement behaviour composition that should be promoted in this age group

Mental health screening using the MINI test in medical students

Introducción: Los trastornos de salud mental constituyen un problema prevalente en alumnos de educación superior, siendo los estudiantes de medicina una población especialmente vulnerable. Objetivos: Determinar la frecuencia de trastornos de salud mental en los alumnos de una escuela de medicina. Diseño: Estudio descriptivo, transversal. Institución: Escuela de Medicina, Universidad Católica Santo Toribio de Mogrovejo, Chiclayo, Lambayeque, Perú. Participantes: Alumnos de una escuela de medicina. Intervenciones: En el semestre académico 2010-I, se evaluó la frecuencia de trastornos de salud mental en los alumnos utilizando el test Mini International Neuropsychiatric Interview (MINI), validado en español, como método de tamizaje. Principales medidas de resultados: Frecuencia de problemas de salud mental. Resultados: Se evaluó 159 estudiantes, 94 del sexo femenino (59,1%) y 65 de sexo masculino (40,8%); la media de la edad fue de 18,6+/- 2,1 años; 35 alumnos (22%) tuvieron al menos un trastorno mental. Los diagnósticos más frecuentes fueron: episodio hipomaniaco pasado (16 alumnos; 10,2%), riesgo suicida (11; 6,9%), trastorno depresivo actual (9; 5,6%), trastorno de angustia actual (8; 5%), agorafobia (8; 5%). En 20 (12,6%) y 11 estudiantes (6,9%), respectivamente, algún profesional de la salud le había diagnosticado previamente ansiedad y depresión. Conclusiones: Los problemas de salud mental fueron frecuentes en esta población de estudiantes, siendo el episodio hipomaniaco pasado, el riesgo suicida y el episodio depresivo actual los más frecuentes.Introduction: Mental health disorders are prevalent in higher education students and medical students are especially vulnerable. Objectives: To determine mental health problems frequency in students of Medicine. Design: Descriptive, transversal study. Setting: School of Medicine, Universidad Catolica Santo Toribio de Mogrovejo, Chiclayo, Lambayeque, Peru. Participants: Medical students. Interventions: During the 2010-I academic semester, frequency of mental health problems were determined using the Mini International Neuropsychiatric Interview (MINI) test, validated in Spanish, as a screening test for mental health. Main outcome measures: Frequency of mental health problems. Results: From 159 students interviewed, 94 were women (59,1%) and 65 men (40,8%). Average age was 18,7+/- 2,1 years; 35 students (22%) had at least one mental disorder. There were 16 (10,2%) students with history of hypomania episode, 11 with suicide risk (6,9%), 9 with current depressive disorder (5,6%), 8 with agoraphobia (4,8%), 8 with current anxiety disorder (4,8%); 20 (12,6%) and 11 (6,9%) students respectively mentioned that a health care provider had previously diagnosed anxiety and depression. Conclusions: Mental health disorders were frequent in these medical students; past hypomania episode, suicidal risk and current depressive disorder were the most frequently diagnosed mental health disorders

Characterization of Leishmania spp. causing cutaneous leishmaniasis in Manaus, Amazonas, Brazil

In the State of Amazonas, American tegumentary leishmaniasis is endemic and presents a wide spectrum of clinical variability due to the large diversity of circulating species in the region. Isolates from patients in Manaus and its metropolitan region were characterized using monoclonal antibodies and isoenzymes belonging to four species of the parasite: Leishmania (Viannia) guyanensis, 73% (153/209); Leishmania (Viannia) braziliensis, 14% (30/209); Leishmania (Leishmania) amazonensis, 8% (17/209); and Leishmania (Viannia) naiffii, 4% (9/209). The most prevalent species was L. (V.) guyanensis. The principal finding of this study was the important quantity of infections involving more than one parasite species, representing 14% (29/209) of the total. The findings obtained in this work regarding the parasite are further highlighted by the fact that these isolates were obtained from clinical samples collected from single lesions

Paleo-landscapes of the Northern Patagonian Massif, Argentina

Fil: Aguilera, Emilia Yolanda. Instituto de Geomorfología y Suelos (IGS). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Rabassa, Jorge. Laboratorio de Geomorfología y Cuaternario. CADIC. Universidad Nacional de Tierra del Fuego; ArgentinaFil: Aragón, Eugenio. Centro de Investigaciones Geológicas (CIG). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin