Dynactin-dependent cortical dynein and spherical spindle shape correlate temporally with meiotic spindle rotation in Caenorhabditis elegans.

Oocyte meiotic spindles orient with one pole juxtaposed to the cortex to facilitate extrusion of chromosomes into polar bodies. In Caenorhabditis elegans, these acentriolar spindles initially orient parallel to the cortex and then rotate to the perpendicular orientation. To understand the mechanism of spindle rotation, we characterized events that correlated temporally with rotation, including shortening of the spindle in the pole-to pole axis, which resulted in a nearly spherical spindle at rotation. By analyzing large spindles of polyploid C. elegans and a related nematode species, we found that spindle rotation initiated at a defined spherical shape rather than at a defined spindle length. In addition, dynein accumulated on the cortex just before rotation, and microtubules grew from the spindle with plus ends outward during rotation. Dynactin depletion prevented accumulation of dynein on the cortex and prevented spindle rotation independently of effects on spindle shape. These results support a cortical pulling model in which spindle shape might facilitate rotation because a sphere can rotate without deforming the adjacent elastic cytoplasm. We also present evidence that activation of spindle rotation is promoted by dephosphorylation of the basic domain of p150 dynactin

Exposure to Moderate Air Pollution during Late Pregnancy and Cord Blood Cytokine Secretion in Healthy Neonates

Ambient air pollution can alter cytokine concentrations as shown in vitro and following short-term exposure to high air pollution levels in vivo. Exposure to pollution during late pregnancy has been shown to affect fetal lymphocytic immunophenotypes. However, effects of prenatal exposure to moderate levels of air pollutants on cytokine regulation in cord blood of healthy infants are unknown. In a birth cohort of 265 healthy term-born neonates, we assessed maternal exposure to particles with an aerodynamic diameter of 10 µm or less (PM₁₀), as well as to indoor air pollution during the last trimester, specifically the last 21, 14, 7, 3 and 1 days of pregnancy. As a proxy for traffic-related air pollution, we determined the distance of mothers' homes to major roads. We measured cytokine and chemokine levels (MCP-1, IL-6, IL-10, IL-1ß, TNF-α and GM-CSF) in cord blood serum using LUMINEX technology. Their association with pollution levels was assessed using regression analysis, adjusted for possible confounders. Mean (95%-CI) PM₁₀ exposure for the last 7 days of pregnancy was 18.3 (10.3-38.4 µg/m³). PM₁₀ exposure during the last 3 days of pregnancy was significantly associated with reduced IL-10 and during the last 3 months of pregnancy with increased IL-1ß levels in cord blood after adjustment for relevant confounders. Maternal smoking was associated with reduced IL-6 levels. For the other cytokines no association was found. Our results suggest that even naturally occurring prenatal exposure to moderate amounts of indoor and outdoor air pollution may lead to changes in cord blood cytokine levels in a population based cohort

Bone mass of female dance students prior to professional dance training: A cross-sectional study

Article Authors Metrics Comments Related Content Abstract Introduction Methods Results Discussion Conclusions Acknowledgments References Reader Comments (0) Media Coverage (0) Figures Abstract Background Professional dancers are at risk of developing low bone mineral density (BMD). However, whether low BMD phenotypes already exist in pre-vocational dance students is relatively unknown. Aim To cross-sectionally assess bone mass parameters in female dance students selected for professional dance training (first year vocational dance students) in relation to aged- and sex-matched controls. Methods 34 female selected for professional dance training (10.9yrs ±0.7) and 30 controls (11.1yrs ±0.5) were examined. Anthropometry, pubertal development (Tanner) and dietary data (3-day food diary) were recorded. BMD and bone mineral content (BMC) at forearm, femur neck (FN) and lumbar spine (LS) were assessed using Dual-Energy X-Ray Absorptiometry. Volumetric densities were estimated by calculating bone mineral apparent density (BMAD). Results Dancers were mainly at Tanner pubertal stage I (vs. stage IV in controls, p<0.001), and demonstrated significantly lower body weight (p<0.001) and height (p<0.01) than controls. Calorie intake was not different between groups, but calcium intake was significantly greater in dancers (p<0.05). Dancers revealed a significantly lower BMC and BMD values at all anatomical sites (p<0.001), and significantly lower BMAD values at the LS and FN (p<0.001). When adjusted for covariates (body weight, height, pubertal development and calcium intake), dance students continued to display a significantly lower BMD and BMAD at the FN (p<0.05; p<0.001) at the forearm (p<0.01). Conclusion Before undergoing professional dance training, first year vocational dance students demonstrated inferior bone mass compared to controls. Longitudinal models are required to assess how bone health-status changes with time throughout professional training

Reactive Oxygen Species Production by Forward and Reverse Electron Fluxes in the Mitochondrial Respiratory Chain

Reactive oxygen species (ROS) produced in the mitochondrial respiratory chain (RC) are primary signals that modulate cellular adaptation to environment, and are also destructive factors that damage cells under the conditions of hypoxia/reoxygenation relevant for various systemic diseases or transplantation. The important role of ROS in cell survival requires detailed investigation of mechanism and determinants of ROS production. To perform such an investigation we extended our rule-based model of complex III in order to account for electron transport in the whole RC coupled to proton translocation, transmembrane electrochemical potential generation, TCA cycle reactions, and substrate transport to mitochondria. It fits respiratory electron fluxes measured in rat brain mitochondria fueled by succinate or pyruvate and malate, and the dynamics of NAD+ reduction by reverse electron transport from succinate through complex I. The fitting of measured characteristics gave an insight into the mechanism of underlying processes governing the formation of free radicals that can transfer an unpaired electron to oxygen-producing superoxide and thus can initiate the generation of ROS. Our analysis revealed an association of ROS production with levels of specific radicals of individual electron transporters and their combinations in species of complexes I and III. It was found that the phenomenon of bistability, revealed previously as a property of complex III, remains valid for the whole RC. The conditions for switching to a state with a high content of free radicals in complex III were predicted based on theoretical analysis and were confirmed experimentally. These findings provide a new insight into the mechanisms of ROS production in RC

Invasive Group B Streptococcus Disease With Recurrence and in Multiples: Towards a Better Understanding of GBS Late-Onset Sepsis.

Group B Streptococcus (GBS) is a common intestinal colonizer during the neonatal period, but also may cause late-onset sepsis or meningitis in up to 0.5% of otherwise healthy colonized infants after day 3 of life. Transmission routes and risk factors of this late-onset form of invasive GBS disease (iGBS) are not fully understood. Cases of iGBS with recurrence (n=25) and those occurring in parallel in twins/triplets (n=32) from the UK and Ireland (national surveillance study 2014/15) and from Germany and Switzerland (retrospective case collection) were analyzed to unravel shared (in affected multiples) or fixed (in recurrent disease) risk factors for GBS disease. The risk of iGBS among infants from multiple births was high (17%), if one infant had already developed GBS disease. The interval of onset of iGBS between siblings was 4.5 days and in recurrent cases 12.5 days. Disturbances of the individual microbiome, including persistence of infectious foci are suggested e.g. by high usage of perinatal antibiotics in mothers of affected multiples, and by the association of an increased risk of recurrence with a short term of antibiotics [aOR 4.2 (1.3-14.2), P=0.02]. Identical GBS serotypes in both recurrent infections and concurrently infected multiples might indicate a failed microbiome integration of GBS strains that are generally regarded as commensals in healthy infants. The dynamics of recurrent GBS infections or concurrent infections in multiples suggest individual patterns of exposure and fluctuations in host immunity, causing failure of natural niche occupation

Feature instructions improve face-matching accuracy

Identity comparisons of photographs of unfamiliar faces are prone to error but important for applied settings, such as person identification at passport control. Finding techniques to improve face-matching accuracy is therefore an important contemporary research topic. This study investigated whether matching accuracy can be improved by instruction to attend to specific facial features. Experiment 1 showed that instruction to attend to the eyebrows enhanced matching accuracy for optimized same-day same-race face pairs but not for other-race faces. By contrast, accuracy was unaffected by instruction to attend to the eyes, and declined with instruction to attend to ears. Experiment 2 replicated the eyebrow-instruc- tion improvement with a different set of same-race faces, comprising both optimized same- day and more challenging different-day face pairs. These findings suggest that instruction to attend to specific features can enhance face-matching accuracy, but feature selection is cru- cial and generalization across face sets may be limited

How does the brain code the race of faces?

High-level perceptual aftereffects have revealed that faces are coded relative to norms, supposedly via some sort of opponent coding mechanism that is dynamically updated by experience. The nature of these norms and the advantage of such a norm-based representation, however, are not yet fully understood. Here, we used high-level adaptation techniques to get insight into the perception of faces of different race categories. We compared the size of identity aftereffects (AEs) for pairs of adapt and test faces that were taken from different morph trajectories, based on potential norms for Asian and Caucasian faces. Larger aftereffects were found following exposure to anti-faces created relative to averages of the race of the target identities, than to anti-faces created using a generic average. Since adapt-test pairs lying opposite to each other in face space generate larger identity AEs than non-opposite test pairs, this suggests that Asian and Caucasian faces are coded using race-specific norms, rather than a generic one. Moreover, we find that identification performance is better for face morphs that are created using these race-specific norms, independent of their actual identity strength. To our knowledge, this is the first evidence for a functional benefit of norms in face recognition

Categorical Perception of Male and Female Faces and the Single-Route Hypothesis

The cognitive process of categorizing perceptually similar stimuli into qualitatively different categories is fundamental to any systematic acting upon the world, as it helps to reduce the immense number of entities to more manageable fragments and spares us from learning anew each time we encounter an unknown individual. Categories are evident in all sensory modalities and range from relatively simple (e. g., color perception) to the most abstract human concepts, as for example faces. Categorical perception (CP) has been shown for face identity (e. g., Beale Keil 1995), ethnicity (Levin Beale, 2000), and facial expression (Calder et al., 1996). Astonishingly, for sex, a natural facial characteristic consisting of only two biologically relevant categories, con icting results have been reported so far. CP for sex has been shown (Campanella et al., 2001) when sex information was varied linearly (by morphing) between male and female face identities, thus intermixing identity and sex information. When sex continua were created based on single face identities (Bultho and Newell, 2004), no CP for sex was found in nave participants. So the question remained open whether or not there is CP for the perception of sex as a facial dimension or if processing of the sex of a face is directly linked to processing of the face's identity, as proposed by the "`single-route hypothesis"' (e. g., by Rossion, 2002, Ganel Goshen Gottstein, 2002; Bultho Newell, 2004). To overcome one potential constraint of earlier studies, i. e., 'asymmetric' sex morph continua, we performed extensive ratings of faces and sex morphs from our face database, to create 'controlled' male and female faces with similar perceived degrees of 'maleness' and 'femaleness'. We then examined CP of sex for these faces with classical discrimination and classication experiments. Critically, we manipulated the degree of familiarization of the faces prior to testing, as follows. Observers were either nave, or familiarized with the average male and female face of all faces, or the endpoint identities of the morph continua, or with other male and female faces with the same perceived degree of maleness and femaleness than the test faces. Our results conrm the lack of naturally occurring CP for sex and provide more evidence for the linked processing of sex and identity, as participants showed clear CP only after familiarization with the test face identities