Migratory birds use head scans to detect the direction of the earth's magnetic field

Night-migratory songbirds are known to use a magnetic compass , but how do they detect the reference direction provided by the geomagnetic field, and where is the sensory organ located? The most prominent characteristic of geomagnetic sensory input, whether based on visual patterns or magnetite-mediated forces , is the predicted symmetry around the north-south or east-west magnetic axis. Here, we show that caged migratory garden warblers perform head-scanning behavior well suited to detect this magnetic symmetry plane. In the natural geomagnetic field, birds move toward their migratory direction after head scanning. In a zero-magnetic field , where no symmetry plane exists, the birds almost triple their head-scanning frequency, and the movement direction after a head scan becomes random. Thus, the magnetic sensory organ is located in the bird's head, and head scans are used to locate the reference direction provided by the geomagnetic field.     

In vitro exposure of human lymphocytes to 900 MHz CW and GSM modulated radiofrequency: studies of proliferation, apoptosis and mitochondrial membrane potential

The aim of this study was to investigate the nonthermal effects of radiofrequency (RF) fields on human immune cells exposed to a Global System for Mobile Communication (GSM) signal generated by a commercial cellular phone and by a sinusoidal non-modulated signal. To assess whether mobile phone RF-field exposure affects human immune cell functions, peripheral blood mononuclear cells (PBMCs) from healthy donors were exposed in vitro to a 900 MHz GSM or continuous-wave (CW) RF field 1 h/day for 3 days in a transverse electromagnetic mode (TEM) cell system (70-76 mW/kg average specific absorption rate, SAR). The cells were cultured for 48 or 72 h, and the following end points were studied: (1) mitogen-induced proliferation; (2) cell cycle progression; (3) spontaneous and 2-deoxy-D-ribose (dRib)-induced apoptosis; (4) mitochondrial membrane potential modifications during spontaneous and dRib-induced-apoptosis. Data obtained from cells exposed to a GSM-modulated RF field showed a slight decrease in cell proliferation when PBMCs were stimulated with the lowest mitogen concentration and a slight increase in the number of cells with altered distribution of phosphatidylserine across the membrane. On the other hand, cell cycle phases, mitochondrial membrane potential and susceptibility to apoptosis were found to be unaffected by the RF field. When cells were exposed to a CW RF field, no significant modifications were observed in comparison with sham-exposed cells for all the end points investigated.     

Nonesterified cholesterol content of lysosomes modulates susceptibility to oxidant-induced permeabilization

Reactive oxygen species (ROS) can induce lysosomal membrane permeabilization (LMP). Photoirradiation of murine hepatoma 1c1c7 cultures preloaded with the photosensitizer NPe6 generates singlet oxygen within acidic organelles and causes LMP and the activation of procaspases. Treatment with the cationic amphiphilic drugs (CADs) U18666A, imipramine, and clozapine stimulated the accumulation of filipin-stainable nonesterified cholesterol/sterols in late endosomes/lysosomes, but not in mitochondria. Concentration-response studies demonstrated an inverse relationship between lysosomal nonesterified cholesterol/sterol contents and susceptibility to NPe6 photoirradiation-induced intracellular membrane oxidation, LMP, and activation of procaspase-9 and -3. Similarly, the kinetics of restoration of NPe6 photoirradiation-induced LMP paralleled the losses of lysosomal cholesterol that occurred upon replating U18666A-treated cultures in CAD-free medium. Consistent with the oxidation of lysosomal cholesterol, filipin staining in U18666A-treated cultures progressively decreased with increasing photoirradiating light dose. U18666A also suppressed the induction of LMP and procaspase activation by exogenously added hydrogen peroxide. However, neither U18666A nor imipramine suppressed the induction of apoptosis by agents that did not directly induce LMP. These studies indicate that lysosomal nonesterified cholesterol/sterol content modulates susceptibility to ROS-induced LMP and possibly does so by being an alternative target for oxidants and lowering the probability of damage to other lysosomal membrane lipids and/or proteins.     

Assessing SSU rDNA Barcodes in Foraminifera: A Case Study using Bolivina quadrata

The Small Subunit Ribosomal RNA gene (SSU rDNA) is a widely used tool to reconstruct phylogenetic relationships among foraminiferal species. Recently, the highly variable regions of this gene have been proposed as DNA barcodes to identify foraminiferal species. However, the resolution of these barcodes has not been well established, yet. In this study, we evaluate four SSU rDNA hypervariable regions (37/f, 41/f, 43/e, and 45/e) as DNA barcodes to distinguish among species of the genus Bolivina, with particular emphasis on Bolivina quadrata for which ten new sequences ( KY468817 – KY468826 ) were obtained during this study. Our analyses show that a single SSU rDNA hypervariable sequence is insufficient to resolve all Bolivina species and that some regions (37/f and 41/f) are more useful than others (43/e and 45/e) to distinguish among closely related species. In addition, polymorphism analyses reveal a high degree of variability. In the context of barcoding studies, these results emphasize the need to assess the range of intraspecific variability of DNA barcodes prior to their application to identify foraminiferal species in environmental samples; our results also highlight the possibility that a longer SSU rDNA region might be required to distinguish among species belonging to the same taxonomic group (i.e. genus).     

Reconciliation and third‐party affiliation in carrion crows

Conflicts are costly because they can damage social relationships. To buffer conflicts, various species use post‐conflict behaviour, such as reconciliation or third‐party affiliation. Both behaviours have predominantly been studied in non‐human primates. However, recently, studies revealed post‐conflict behaviour in other mammalian and some bird species (e.g., corvids). While third‐party affiliation has been reported in several corvid species, reconciliation has only rarely been observed. The social structure of the studied groups has been postulated as a reason for the absence of reconciliation. Here, we investigated whether post‐conflict behaviours in corvids indeed mirror the relationship structure. We studied the behaviour of a newly established group of juvenile carrion crows (Corvus corone corone), where pair bonds had not yet been established. We applied a combination of observations and food monopolisation experiments to quantify the use of post‐conflict behaviours. Provisioning food in one or two pieces induced different patterns of aggression during feeding and differently affected the affiliation patterns after feeding. Specifically, victims of severe aggression affiliated with third parties after conflicts in the two‐piece condition, while aggressors affiliated with victims of mild aggression in the one‐piece condition. We thus provide the first evidence that a corvid species, crows, flexibly engage in both third‐party affiliation and reconciliation.     

Aggrecan modulation of growth plate morphogenesis

Chick and mouse embryos with heritable deficiencies of aggrecan exhibit severe dwarfism and premature death, demonstrating the essential involvement of aggrecan in development. The aggrecan-deficient nanomelic (nm) chick mutant E12 fully formed growth plate (GP) is devoid of matrix and exhibits markedly altered cytoarchitecture, proliferative capacity, and degree of cell death. While differentiation of chondroblasts to pre-hypertrophic chondrocytes (IHH expression) is normal up to E6, the extended periosteum expression pattern of PTCH (a downstream effector of IHH) indicates altered propagation of IHH signaling, as well as accelerated down-regulation of FGFR3 expression, decreased BrdU incorporation and higher levels of ERK phosphorylation, all indicating early effects on FGF signaling. By E7 reduced IHH expression and premature expression of COL10A1 foreshadow the acceleration of hypertrophy observed at E12. By E8, exacerbated co-expression of IHH and COL10A1 lead to delayed separation and establishment of the two GPs in each element. By E9, increased numbers of cells express P-SMAD1/5/8, indicating altered BMP signaling. These results indicate that the IHH, FGF and BMP signaling pathways are altered from the very beginning of GP formation in the absence of aggrecan, thereby inducing premature hypertrophic chondrocyte maturation, leading to the nanomelic long bone growth disorder.     

Role of Weight History on Functional Limitations and Disability in Late Adulthood: The ARIC Study

Objective: To examine associations of weight history with functional limitations and disability in white and African‐American men and women. Research Methods and Procedures: Data were from the Atherosclerosis Risk in Communities study (n = 11, 177). Associations of recalled weight status at age 25 and weight change from age 25 to ages 45 to 64 with functional limitations, activities of daily living (ADLs), and instrumental activities of daily living (IADLs) at follow‐up (ages 52 to 75) were examined using logistic regression. Results: Obesity (BMI ≥ 30 kg/m²) at age 25 was associated with functional limitations and ADL and IADL impairment at follow‐up in white and African‐American men and women. For example, obese compared with normal weight (BMI, 18.5 to 24.9 kg/m²) white women had higher odds of mild [odds ratio (95% confidence interval), 1.97 (1.18 to 3.29)] and severe [9.81 (5.92 to 16.27)] functional limitations and ADL [3.48 (2.36 to 5.13)] and IADL [2.95 (2.00 to 4.33)] impairment. In African‐American women, obesity was associated with higher odds of mild [2.71 (1.14 to 6.41)] and severe [6.01 (2.53 to 14.26)] functional limitations and ADL [1.82 (1.10 to 3.00)] and IADL [2.39 (1.47 to 3.90)] impairment. Similar associations were found in men. Compared with weight maintenance (±10 lbs), large weight gain (>30 lbs) from age 25 to ages 45 to 64 was also associated with functional limitations and ADL and IADL impairment in white and African‐American men and women. Discussion: Maintenance of a healthy body weight throughout adulthood may play a role in preventing or delaying the onset of functional limitations and disability, resulting in increased quality of life and decreased health care costs.     

Sequencing of multiple clostridial genomes related to biomass conversion and biofuel production

Modern methods to develop microbe-based biomass conversion processes require a system-level understanding of the microbes involved. Clostridium species have long been recognized as ideal candidates for processes involving biomass conversion and production of various biofuels and other industrial products. To expand the knowledge base for clostridial species relevant to current biofuel production efforts, we have sequenced the genomes of 20 species spanning multiple genera. The majority of species sequenced fall within the class III cellulosome-encoding Clostridium and the class V saccharolytic Thermoanaerobacteraceae. Species were chosen based on representation in the experimental literature as model organisms, ability to degrade cellulosic biomass either by free enzymes or by cellulosomes, ability to rapidly ferment hexose and pentose sugars to ethanol, and ability to ferment synthesis gas to ethanol. The sequenced strains significantly increase the number of noncommensal/nonpathogenic clostridial species and provide a key foundation for future studies of biomass conversion, cellulosome composition, and clostridial systems biology.