Dynamic association of human insulin receptor with lipid rafts in cells lacking caveolae

Cholesterol-sphingolipid rich plasma membrane domains, known as rafts, have emerged as important regulators of signal transduction. The adipocyte insulin receptor (IR) is localized to and signals via caveolae that are formed by polymerization of caveolins. Caveolin binds to IR and stimulates signalling. We report that, in liver-derived cells lacking caveolae, autophosphorylation of the endogenous IR is dependent on raft lipids, being compromised by acute cyclodextrin-mediated cholesterol depletion or by antibody clustering of glycosphingolipids. Moreover, we provide evidence that IR becomes recruited to detergent-resistant domains upon ligand binding and that clustering of GM2 ganglioside inhibits IR signalling apparently by excluding the ligand-bound IR from these domains. Our results indicate that, in cells derived from liver, an important insulin target tissue, caveolae are not required for insulin signalling. Rather, the dynamic recruitment of the ligand-bound IR into rafts may serve to regulate interactions in the initiation of the IR signalling cascade.     

Microsatellite diversity associated with ecological factors in Hordeum spontaneum populations in Israel

Microsatellite diversity at 18 loci was analysed in 94 individual plants of 10 wild barley, Hordeum spontaneum (C. Koch) Thell., populations sampled from Israel across a southward transect of increasing aridity. Allelic distribution in populations was not distributed randomly. Estimates of mean gene diversity were highest in stressful arid-hot environments. Sixty-four per cent of the genetic variation was partitioned within populations and 36% between populations. Associations between ecogeographical variables and gene diversity, H(e), were established in nine microsatellite loci. By employing principle component analysis we reduced the number of ecogeographical variables to three principal components including water factors, temperature and geography. At three loci, stepwise multiple regression analysis explained significantly the gene diversity by a single principal component (water factors). Based on these observations it is suggested that simple sequence repeats are not necessarily biologically neutral.     

Eveningness associates with smoking and sleep problems among pregnant women

Sleep problems during pregnancy impair maternal health and increase the risk for adverse pregnancy outcome. The circadian preference toward eveningness has been associated with sleep problems in previous studies. Here, we studied whether evening-type women had more sleep problems during their pregnancy, as compared with other chronotypes, in a sample consisting of 1653 pregnant women from the Finnish CHILD-SLEEP Birth Cohort. Chronotype was assessed with a shortened version of the morningness–eveningness questionnaire. Pregnant evening-type women reported more sleep problems, including troubles of falling asleep (OR = 3.4, p < 0.0001), poor sleep quality (OR = 2.9, p < 0.01) and daily tiredness (OR = 3.2, p < 0.0001) than the morning-type women, even after controlling for sleep duration and sleep deprivation. They had higher scores on Epworth Sleepiness Scale (p < 0.05), Basic Nordic Sleep Questionnaire (p < 0.0001) and Global Seasonality Score (p < 0.01) and were also more often smokers, also during pregnancy (p < 0.001) and reported poorer general health (p < 0.001) than the morning-type women. They also reported having had more sleep problems during their childhood (OR = 1.5, p < 0.05) and adolescence (OR = 2.0, p < 0.001) than the morning-type women. Our results indicate that eveningness is associated with more sleep problems and unhealthy life habits during pregnancy.     

Sleep architecture is related to the season of PSG recording in 8-month-old infants

ABSTRACT

To date, little is known about the impact of season on infant sleep. In higher latitudes, the duration of daily light time varies substantially between different seasons, and environmental light is one potential factor affecting sleep. In this cohort study, one-night polysomnography (PSG) was performed on 72 healthy 8-month-old infants in 2012 and 2013 to study the effect of season on the sleep architecture of young infants in Finland. The children were divided into four subgroups, according to the amount of light during their birth season and the amount of light during the season of the PSG recordings, corresponding to spring, summer, autumn, and winter. We found that the season of birth did not have an impact on the infants’ sleep architecture at 8 months of age, but the season of the PSG recording did have an effect on several sleep variables. In the PSGs conducted during the spring, there was less N3 sleep and more N2 sleep than in the PSGs conducted during the autumn. In addition, there was more fragmented sleep during spring than autumn. According to our data, the season has an effect on the sleep architecture of young infants and should, therefore, be considered when evaluating the PSG findings of young infants. The exact mechanisms behind this novel finding remain unclear, however. The findings imply that infants` sleep is affected by the season or light environment, as is the case in adult sleep. Since potential explanatory factors, such as direct natural or artificial light exposure and the melatonin levels of the infants, were not controlled, more research is needed in the future to better understand this phenomenon.     

Diapause affects cuticular hydrocarbon composition and mating behavior of both sexes in Drosophila montana

Envipnmental cues,mainly photoperiod and temperature,are known to control female adult reproductive diapause in several insect species.Diapause enhances female survival during adverse conditions and postpones progeny production to the favorable season.Male diapause(a reversible inability to inseminate receptive females)has been studied much less than female diapause.However,if the males maximized their chances to fertilize females while minimizing their energy expenditure,they would be expected to be in diapause at the same time as females.We investigated Drosophila montana male mating bchavior under short-day conditions that induce diapause in females and found the males to be reproductively inactive.We also found that males reared under long-day conditions(reproducing individuals)court reproducing postdiapause fermales,but not diapausing ones.The diapausing fies of both sexes had more long-chain and less short-chain hydrocarbons on their cuticle than the reproducing ones,which presumably increase their survival under stressful conditions,but at the same time decrease their attractiveness.Our study shows that the mating behavior of females and males is well coordinated during and afier overwintering and it also gives support to the dual role of insect cuticular hydrocarbons in adaptation and mate choice.     

Novel mutation G324C in <Emphasis Type="Italic">WNT1</Emphasis> mapped in a large Pakistani family with severe recessively inherited <Emphasis Type="Italic">Osteogenesis Imperfecta</Emphasis>

Introduction

Osteogenesis imperfecta (OI) is a clinically and genetically heterogeneous disease with skeletal fragility and variable extra-skeletal manifestations. To date several point mutations in 18 different genes causing different types of OI have been identified. Mutations in WNT1 compromise activity of the osteoblasts leading to disturbed bone mass accrual, fragility fractures and progressive skeletal abnormalities. The present study was conducted to determine the underlying genetic cause of an autosomal recessive skeletal dysplasia in a large consanguineous family from Chinute, Pakistan.

Materials and methods

Blood was collected from 24 individuals of affected family along with clinical data. Homozygosity mapping was performed to confirm consanguinity. SNPs were identified, followed by whole exome and Sanger sequencing. In silico characterization of WNT1 mutation was performed using multiple platforms.

Results

Nine affected family members exhibited severe bone deformities, recurrent fractures, short stature and low bone mineral density. SNP array data revealed homozygous segments >?1 Mb in length accounting for 2.1–12.7% of the genome in affected individuals and their siblings and a single 6,344,821 bp homozygous region in all affected individuals on chromosome 12q12-q13. This region includes two potential OI candidate genes WNT1 and VDR. We did whole-exome sequencing for both genes in two patients and identified a novel damaging missense mutation in exon 4 of WNT1: c.1168G?>?T (NM_005430) resulting in p.G324C. Sanger sequencing confirmed segregation of mutation with the disease in family.

Conclusion

We report a novel mutation responsible for OI and our investigation expands the spectrum of disease-causing WNT1 mutations and the resulting OI phenotypes.

     

How does biodiversity conservation argumentation generate effects in policy cycles?

Arguments in the formulation, implementation and evaluation of biodiversity policy frame conservation in a range of ways and express interests that can be conflicting. Policy processes are cyclic and iterative by nature and as policies are constantly reformulated, argumentation has an important role at each policy stage. In this paper, we utilise the policy cycle model to shed light on biodiversity-related policy processes and the ways in which argumentation generates effects at different stages of these processes. The paper first draws on literature and the theory-driven assumptions are then illustrated with insights from four European case studies on different policy processes in which biodiversity conservation plays a role. The analysis shows that argumentation tends to evolve over the course of the policy cycle, and framing has a key role across the different policy stages. It is concluded that the ways in which arguments persist, accumulate, diffuse, and replace old arguments, should be the target of increased attention in policy analysis.     

Ecosystem state shifts during long‐term development of an Amazonian peatland

The most carbon (C)‐dense ecosystems of Amazonia are areas characterized by the presence of peatlands. However, Amazonian peatland ecosystems are poorly understood and are threatened by human activities. Here, we present an investigation into long‐term ecohydrological controls on C accumulation in an Amazonian peat dome. This site is the oldest peatland yet discovered in Amazonia (peat initiation ca. 8.9 ka BP), and developed in three stages: (i) peat initiated in an abandoned river channel with open water and aquatic plants; (ii) inundated forest swamp; and (iii) raised peat dome (since ca. 3.9 ka BP). Local burning occurred at least three times in the past 4,500 years. Two phases of particularly rapid C accumulation (ca. 6.6–6.1 and ca. 4.9–3.9 ka BP), potentially resulting from increased net primary productivity, were seemingly driven by drier conditions associated with widespread drought events. The association of drought phases with major ecosystem state shifts (open water wetland–forest swamp–peat dome) suggests a potential climatic control on the developmental trajectory of this tropical peatland. A third drought phase centred on ca. 1.8–1.1 ka BP led to markedly reduced C accumulation and potentially a hiatus during the peat dome stage. Our results suggest that future droughts may lead to phases of rapid C accumulation in some inundated tropical peat swamps, although this can lead ultimately to a shift to ombrotrophy and a subsequent return to slower C accumulation. Conversely, in ombrotrophic peat domes, droughts may lead to reduced C accumulation or even net loss of peat. Increased surface wetness at our site in recent decades may reflect a shift towards a wetter climate in western Amazonia. Amazonian peatlands represent important carbon stores and habitats, and are important archives of past climatic and ecological information. They should form key foci for conservation efforts.     

Contractility and structure of adult rat seminiferous tubules in organ culture

Summary Isolated pieces of seminiferous tubules of adult rats were grown in organ culture for up to 8 weeks in Petri dishes on the surface of nutrient agar. The medium consisted of newborn calf serum, Eagle's minimum essential medium, glutamate and antibiotics. This method allowed observation of the contractions of the seminiferous tubules in the culture. Contractility, light and electron microscopic structure and histochemically demonstrable activities of alkaline phosphatase and ATPase of the tubule walls were studied at 1-week intervals. The contractility and alkaline phosphatase activity were maintained in the tubule wall for 3 weeks, and the activity of ATPase was maintained for 5 weeks. The thin filaments of the myoid cells, which are responsible for the contractility, were seen with the electron microscope in tubules cultured for 5 weeks. The organ culture method described in the present paper seems to be valuable for studies concerning the functioning of the myoid cells of the seminiferous tubules and the possibility that this is regulated by hormones.