Intact flagellar motor of Borrelia burgdorferi revealed by cryo-electron tomography: evidence for stator ring curvature and rotor/C-ring assembly flexion.

The bacterial flagellar motor is a remarkable nanomachine that provides motility through flagellar rotation. Prior structural studies have revealed the stunning complexity of the purified rotor and C-ring assemblies from flagellar motors. In this study, we used high-throughput cryo-electron tomography and image analysis of intact Borrelia burgdorferi to produce a three-dimensional (3-D) model of the in situ flagellar motor without imposing rotational symmetry. Structural details of B. burgdorferi, including a layer of outer surface proteins, were clearly visible in the resulting 3-D reconstructions. By averaging the 3-D images of approximately 1,280 flagellar motors, a approximately 3.5-nm-resolution model of the stator and rotor structures was obtained. flgI transposon mutants lacked a torus-shaped structure attached to the flagellar rod, establishing the structural location of the spirochetal P ring. Treatment of intact organisms with the nonionic detergent NP-40 resulted in dissolution of the outermost portion of the motor structure and the C ring, providing insight into the in situ arrangement of the stator and rotor structures. Structural elements associated with the stator followed the curvature of the cytoplasmic membrane. The rotor and the C ring also exhibited angular flexion, resulting in a slight narrowing of both structures in the direction perpendicular to the cell axis. These results indicate an inherent flexibility in the rotor-stator interaction. The FliG switching and energizing component likely provides much of the flexibility needed to maintain the interaction between the curved stator and the relatively symmetrical rotor/C-ring assembly during flagellar rotation.

Chronic spontaneous activity generated in the somata of primary nociceptors is associated with pain-related behavior after spinal cord injury.

Mechanisms underlying chronic pain that develops after spinal cord injury (SCI) are incompletely understood. Most research on SCI pain mechanisms has focused on neuronal alterations within pain pathways at spinal and supraspinal levels associated with inflammation and glial activation. These events might also impact central processes of primary sensory neurons, triggering in nociceptors a hyperexcitable state and spontaneous activity (SA) that drive behavioral hypersensitivity and pain. SCI can sensitize peripheral fibers of nociceptors and promote peripheral SA, but whether these effects are driven by extrinsic alterations in surrounding tissue or are intrinsic to the nociceptor, and whether similar SA occurs in nociceptors in vivo are unknown. We show that small DRG neurons from rats (Rattus norvegicus) receiving thoracic spinal injury 3 d to 8 months earlier and recorded 1 d after dissociation exhibit an elevated incidence of SA coupled with soma hyperexcitability compared with untreated and sham-treated groups. SA incidence was greatest in lumbar DRG neurons (57%) and least in cervical neurons (28%), and failed to decline over 8 months. Many sampled SA neurons were capsaicin sensitive and/or bound the nociceptive marker, isolectin B4. This intrinsic SA state was correlated with increased behavioral responsiveness to mechanical and thermal stimulation of sites below and above the injury level. Recordings from C- and Aδ-fibers revealed SCI-induced SA generated in or near the somata of the neurons in vivo. SCI promotes the entry of primary nociceptors into a chronic hyperexcitable-SA state that may provide a useful therapeutic target in some forms of persistent pain.

Clinical Significance of 3D Ultrasound Compared to MRI in Uterine Malformations

Purpose: Congenital uterine anomalies often remain asymptomatic until they cause problems, for example during pregnancy. We studied the diagnostic aspects of two- and three-dimensional ultrasound and MRI. Materials and Methods: 63 women referred for suspected uterine anomalies were studied: In the first group (until July 2008) with 2 D-US and MRI, in the second group (from August 2008) additionally with 3 D-US; these women also had diagnostic or therapeutic operative confirmation. In the third group, only 3D-US was used. Results: In all women 3D-US was possible and successful. The most common anomaly was a subseptate uterus, while a septate uterus was less frequent, and uterus bicornis (unicollis) and uterus didelphys (bicornis bicollis) were rare. The women in the first two groups all underwent at least diagnostic hysteroscopy, and some (subseptate or septate uterus) underwent operative hysteroscopy. After preoperative volume imaging, laparoscopies were required less often. 3D-US diagnoses as judged by intraoperative findings were correct in 100 % of cases, while the MRI diagnoses in the same group were correct in only 7/13 cases. Conclusion: Since the introduction of volume imaging (MRI, later 3 D-US), laparoscopy during hysteroscopic septum resection was not necessary in the majority of cases. 3D-US brings the diagnostics of uterine anomalies back into the hands of the gynecologist and can provide the gynecological surgeon with a higher subjective degree of certainty during operative hysteroscopy.

Fetal lungs of tenascin-C-deficient mice grow well, but branch poorly in organ culture

Tenascin-C (TNC) is a multidomain extracellular matrix protein that contributes to organogenesis and tumorgenesis. To elucidate its developmental function in the context of TNC deficiency, lung lobes of TNC null mice were obtained at Embryonic Days E11.5 and E12.5 and cultured for 3 d. In lung explants of homozygote TNC-deficient embryos (E12.5) the number of future airway branches was reduced by 36% as compared with wild-type. In heterozygote explants only half of the reduction (18%) was observed. No significant alteration, neither of the explant growth nor of the pattern of airway branching, was noticed in TNC-null explants. However, the terminal endbuds of the transgenic explants were enlarged. The results are supported by a morphologic investigation at Postnatal Day P2, where the airspaces of TNC-deficient lungs appeared larger than in wild-type lungs. Taken together, our results represent the first developmental phenotype of TNC-null mice. We conclude that TNC takes part in the control of fetal lung branching, and that not only the presence of TNC but also its amount is important. Because TNC is predominantly expressed at the growing tip of the future airways, we hypothesize that TNC promotes the penetration into the surrounding mesenchyme and the branching of the growing airways.

Three-dimensional Vortex Structures on Heated Micro-lattice in a Gas

This paper addresses the microscale heat transfer problem from heated lattice to the gas. A micro-device for enhanced heat transfer is presented and numerically investigated. Thermal creep induces 3-D vortex structures in the vicinity of the lattice. The gas flow is in the slip flow regime (Knudsen number Kn⩽0.1Kn⩽0.1). The simulations are performed using slip flow Navier–Stokes equations with boundary condition formulations proposed by Maxwell and Smoluchowski. In this study the wire thicknesses and distances of the heated lattice are varied. The surface geometrical properties alter significantly heat flux through the surface.

Along-Strike Differences in the Southern Alps of New Zealand: Consequences of Inherited Variation in Rheology

Long- and short-term strain variations along the Australian-Pacific plate boundary through the South Island of New Zealand, including a 300% increase in orogen width, coexistence of oblique thrusting on orthogonal structures, and variability in the locus of orogenic gold deposits, coincide with rheologically relevant geological variation. Our model investigates the consequences of thin, strong lower crust in the north and thick, weak lower crust in the south. Solution of the full 3-D mechanical equations reproduces the larger wavelength strain patterns of the orogen. A 3-D perturbation-based analytical solution leads to the identification of the sensitivity of displacement type to minor stress changes. Transition from boundary-normal thrusting to boundary-parallel thrusting occurs at the transition from strong to weak lower crust and is related to an increase in either tau(yz) (shear stress in the yz plane) or the ratio of the coordinate normal stresses, (sigma(yy)/sigma(xx)), where x and y are in the horizontal and z is vertical. Both mechanisms are compatible with the geologically dependent rheological variation employed in our model. Citation: Upton, P., P. O. Koons, D. Craw, C. M. Henderson, and R. Enlow (2009), Along-strike differences in the Southern Alps of New Zealand: Consequences of inherited variation in rheology, Tectonics, 28, TC2007, doi:10.1029/2008TC002353.

Seasonal Geophysical Monitoring of Biogenic Gases in a Northern Peatland: Implications for Temporal and Spatial Variability in Free Phase Gas Production Rates

A set of high resolution surface ground penetrating radar (GPR) surveys, combined with elevation rod ( to monitor surface deformation) and gas flux measurements, were used to investigate in situ biogenic gas dynamics within a northern peatland (Caribou Bog, Maine). Gas production rates were directly estimated from the time series of GPR measurements. Spatial variability in gas production was also investigated by comparing two sites with different geological and ecological attributes, showing differences and/or similarities depending on season. One site characterized by thick highly humified peat deposits (5-6 m), wooded heath vegetation and open pools showed large ebullition events during the summer season, with estimated emissions (based on an assumed range of CH(4) concentration) between 100 and 172 g CH(4) m(-2) during a single event. The other site characterized by thinner less humified peat deposits (2-3 m) and shrub vegetation showed much smaller ebullition events during the same season (between 13 and 23 g CH(4) m(-2)). A consistent period of free-phase gas (FPG) accumulation during the fall and winter, enhanced by the frozen surficial peat acting as a confining layer, was followed by a decrease in FPG after the snow/ice melt that released estimated fluxes between 100 and 200 g CH(4) m(-2) from both sites. Estimated FPG production rates during periods of biogenic gas accumulation ranged between 0.22 and 2.00 g CH(4) m(3) d(-1) and reflected strong seasonal and spatial variability associated with differences in temperature, peat soil properties, and/or depositional attributes (e. g., stratigraphy). Periods of decreased atmospheric pressure coincided with short-period increases in biogenic gas flux, including a very rapid decrease in FPG content associated with an ebullition event that released an estimated 39 and 67 g CH(4) m(-2) in less than 3.5 hours. These results provide insights into the spatial and seasonal variability in production and emission of biogenic gases from northern peatlands.

Descaling Injury Impairs the Osmoregulatory Ability of Atlantic Salmon Smolts Entering Seawater

The effect of descaling injury on the osmoregulatory ability of hatchery Atlantic salmon Salmo salar smolts in seawater was investigated. Experimental series were initiated during early, middle, and late periods of the spring smolt migration (April 25, May 11, and May 31, respectively). For each time series, descaled smolts (subjected to descaling on 10% of the body surface area) and control smolts (held out of water for 15 s) were transferred to seawater at 0, 1, 3, or 7 d posttreatment. After fish were held in 35% seawater for 24 h, gill and blood samples were collected and analyzed for Na(+),K(+)-ATPase activity and plasma osmolyte levels. Based on gill Na(+),K(+)-ATPase activity, the three series spanned the period from early smolting (increasing activity) to de-smolting (decreasing activity). In each series, descaled fish transferred to seawater at 0 and 1 d posttreatment had greater plasma osmolality than control fish; descaled fish transferred to seawater at 3 d posttreatment did not differ from controls. The greatest perturbation in osmolality (70 milliosmoles) was observed at the peak of smolting (middle series), whereas lesser increases were seen for early and late-series smolts. The observed osmotic perturbations in descaled fish would probably reduce performance and decrease survival during smolt migration.

Subharmonic Mixer Based on EBG Technology

We present the design of a submillimeter-wave mixer based on electromagnetic band gap (EBG) technology and using subharmonic local oscillator (LO) injection. The indicated device converts an incoming submilimeter wavelength signal into a 1-5 GHz intermediate frequency (IF) signal by mixing it with a subharmonic LO signal. The mixer consists of a dual-band receiver and two coplanar stripline (CPS) filters, collocated on top of a three-dimensional (3-D) EBG structure. A four-element array of the proposed receivers was designed, fabricated and tested. The configuration demonstrated reasonable performance: conversion loss below 8 dB and noise temperature below 3000 K. The presented concept can be used for higher frequencies, provided the availability of sufficiently powerful LO sources.

Factors of Home Dream Recall and Nightmare Frequency in a Non-Student Sample

Home dream recall frequencies and nightmare frequencies show great inter-individual differences. Most of the studies trying to explain these differences, however, studied young participants, so these findings might not be true for persons older than 25 years. The present study investigated the relationship between dream recall, nightmare frequency, age, gender, sleep parameters, stress, and subjective health in a community-based sample (N = 455) with a mean age of about 55 years. Some of the factors that have been shown to be associated with dream recall and nightmare frequency were also associated with these variables in non-student sample like frequency of nocturnal awakenings, current stress, and tiredness during the day. We were not able to replicate the effect of sex-role orientation on dream recall and nightmare frequency, supporting the idea that age might mediate the effect of daytime variables on dream recall and nightmare frequency. As nightmare frequency was related to sleep quality, stress, health problems, and tiredness during the day, it would be desirable that clinicians include a question about nightmares in their anamneses.

Beta-alanine supplementation improves jumping power and affects severe-intensity performance in professional alpine skiers.

INTRODUCTION Supplementation with beta-alanine may have positive effects on severe-intensity, intermittent, and isometric strength-endurance performance. These could be advantageous for competitive alpine skiers, whose races last 45 to 150 s, require metabolic power above the aerobic maximum, and involve isometric muscle work. Further, beta-alanine supplementation affects the muscle force-frequency relationship, which could influence explosiveness. We explored the effects of beta-alanine on explosive jump performance, severe exercise energy metabolism, and severe-intensity ski-like performance. METHODS Nine male elite alpine skiers consumed 4.8 g/d beta-alanine or placebo for 5 weeks in a double-blind fashion. Before and after, they performed countermovement jumps (CMJ), a 90-s cycling bout at 110% VO2max (CLT), and a maximal 90-s box jump test (BJ90). RESULTS Beta-alanine improved maximal (+7 ± 3%, d = 0.9) and mean CMJ power (+7 ± 2%, d = 0.7), tended to reduce oxygen deficit (-3 ± 8%, p = .06) and lactate accumulation (-12 ± 31%) and enhance aerobic energy contribution (+1.3 ± 2.9%, p = .07) in the CLT, and improved performance in the last third of BJ90 (+7 ± 4%, p = .02). These effects were not observed with placebo. CONCLUSIONS Beta-alanine supplementation improved explosive and repeated jump performance in elite alpine skiers. Enhanced muscle contractility could possibly explain improved explosive and repeated jump performance. Increased aerobic energy production could possibly help explain repeated jump performance as well.

Comparison of energy expenditure, eating pattern and physical activity of grazing and zero-grazing dairy cows at different time points during lactation

An experiment was conducted to determine the effect of grazing versus zero-grazing on energy expenditure (EE), feeding behaviour and physical activity in dairy cows at different stages of lactation. Fourteen Holstein cows were subjected to two treatments in a repeated crossover design with three experimental series (S1, S2, and S3) reflecting increased days in milk (DIM). At the beginning of each series, cows were on average at 38, 94 and 171 (standard deviation (SD) 10.8) DIM, respectively. Each series consisted of two periods containing a 7-d adaptation and a 7-d collection period each. Cows either grazed on pasture for 16–18.5 h per day or were kept in a freestall barn and had ad libitum access to herbage harvested from the same paddock. Herbage intake was estimated using the double alkane technique. On each day of the collection period, EE of one cow in the barn and of one cow on pasture was determined for 6 h by using the 13C bicarbonate dilution technique, with blood sample collection done either manually in the barn or using an automatic sampling system on pasture. Furthermore, during each collection period physical activity and feeding behaviour of cows were recorded over 3 d using pedometers and behaviour recorders. Milk yield decreased with increasing DIM (P<0.001) but was similar with both treatments. Herbage intake was lower (P<0.01) for grazing cows (16.8 kg dry matter (DM)/d) compared to zero-grazing cows (18.9 kg DM/d). The lowest (P<0.001) intake was observed in S1 and similar intakes were observed in S2 and S3. Within the 6-h measurement period, grazing cows expended 19% more (P<0.001) energy (319 versus 269 kJ/kg metabolic body size (BW0.75)) than zero-grazing cows and differences in EE did not change with increasing DIM. Grazing cows spent proportionally more (P<0.001) time walking and less time standing (P<0.001) and lying (P<0.05) than zero-grazing cows. The proportion of time spent eating was greater (P<0.001) and that of time spent ruminating was lower (P<0.05) for grazing cows compared to zero-grazing cows. In conclusion, lower feed intake along with the unchanged milk production indicates that grazing cows mobilized body reserves to cover additional energy requirements which were at least partly caused by more physical activity. However, changes in cows׳ behaviour between the considered time points during lactation were too small so that differences in EE remained similar between treatments with increasing DIM.

On vertical electric fields at lunar magnetic anomalies

We study the interaction between a magnetic dipole mimicking the Gerasimovich magnetic anomaly on the lunar surface and the solar wind in a self-consistent 3-D quasi-neutral hybrid simulation where ions are modeled as particles and electrons as a charge-neutralizing fluid. Especially, we consider the origin of the recently observed electric potentials at lunar magnetic anomalies. An antimoonward Hall electric field forms in our simulation resulting in a potential difference of <300V on the lunar surface, in which the value is similar to observations. Since the hybrid model assumes charge neutrality, our results suggest that the electric potentials at lunar magnetic anomalies can be formed by decoupling of ion and electron motion even without charge separation.

Terrestrial Radar Interferometric Measurement of Hillslope Deformation and Atmospheric Disturbances in the Illgraben Debris-Flow Catchment, Switzerland

We describe a method for rapid identification and precise quantification of slope deformation using a portable radar interferometer. A rockslide with creep-like behavior was identified in the rugged and inaccessible headwaters of the Illgraben debris-flow catchment, located in the Central Swiss Alps. The estimated volume of the moving rock mass was approximately 0.5 x 10(6) m(3) with a maximum daily (3-D) displacement rate of 3 mm. Fast scene acquisition in the order of 6 s/scene led to uniquely precise mapping of spatial and temporal variability of atmospheric phase delay. Observations led to a simple qualitative model for prediction of atmospheric disturbances using a simple model for solar radiation, which can be used for advanced campaign planning for short observation periods (hours to days).