Characterization of the gene for an immunodominant 72 kDa lipoprotein of Mycoplasma mycoides subsp. mycoides small colony type.

With the aim of characterizing specific immunogenic proteins of Mycoplasma mycoides subsp. mycoides small colony (SC) type, the aetiological agent of contagious bovine pleuropneumonia, a gene encoding a major immunogenic protein of 72 kDa named P72 was cloned and expressed in Escherichia coli. The expressed protein was of the same apparent molecular mass as that produced by the parent strain. The predicted molecular mass of P72, based on the DNA-deduced amino acid sequence, was 61.118 kDa, significantly lower than the apparent molecular mass of endogenous or recombinant P72 on SDS-PAGE. Analysis of the amino acid sequence revealed a typical prokaryotic signal peptidase II-membrane lipoprotein lipid attachment site and a transmembrane structure domain in the leader sequence at the amino-terminal end of the protein. P72 was shown to be a lipoprotein and its surface location was confirmed by trypsin treatment of whole cells. An unassigned gene encoding a peptide with some similarity to P72 was found on the genome sequence of M. capricolum subsp. capricolum but not on that of Mycoplasma genitalium. The P72 gene was detected in 11/11 M. mycoides subsp. mycoides SC strains. Antiserum against recombinant P72 reacted strongly with 12/12 strains of M. mycoides subsp. mycoides SC, weakly with Mycoplasma bovine group 7 strain PG50, but not with other members of the 'mycoides cluster' or closely related mycoplasmas. Cows experimentally contact-infected with M. mycoides subsp. mycoides SC developed a humoral response against P72 within 35 d. P72 is a specific antigenic membrane lipoprotein of M. mycoides subsp. mycoides SC with potential for use in development of diagnostic reagents. It seems to belong to a family of lipoproteins of the "mycoides cluster'.

Is complex signal processing for bone conduction hearing aids useful?

OBJECTIVES To establish whether complex signal processing is beneficial for users of bone anchored hearing aids. METHODS Review and analysis of two studies from our own group, each comparing a speech processor with basic digital signal processing (either Baha Divino or Baha Intenso) and a processor with complex digital signal processing (either Baha BP100 or Baha BP110 power). The main differences between basic and complex signal processing are the number of audiologist accessible frequency channels and the availability and complexity of the directional multi-microphone noise reduction and loudness compression systems. RESULTS Both studies show a small, statistically non-significant improvement of speech understanding in quiet with the complex digital signal processing. The average improvement for speech in noise is +0.9 dB, if speech and noise are emitted both from the front of the listener. If noise is emitted from the rear and speech from the front of the listener, the advantage of the devices with complex digital signal processing as opposed to those with basic signal processing increases, on average, to +3.2 dB (range +2.3 … +5.1 dB, p ≤ 0.0032). DISCUSSION Complex digital signal processing does indeed improve speech understanding, especially in noise coming from the rear. This finding has been supported by another study, which has been published recently by a different research group. CONCLUSIONS When compared to basic digital signal processing, complex digital signal processing can increase speech understanding of users of bone anchored hearing aids. The benefit is most significant for speech understanding in noise.

Measurement and stability of the pointing of the BepiColombo Laser Altimeter under thermal load

The BepiColombo Laser Altimeter (BELA) has been selected to fly on ESA׳s BepiColombo mission to Mercury. The instrument will be the first European laser altimeter designed for interplanetary flight. This paper describes the setup used to characterize the angular movements of BELA under the simulated environmental conditions that the instrument will encounter when orbiting Mercury. The system comprises a laser transmitter and a receiving telescope, which can move with respect to each other under thermal load. Tests performed using the Engineering Qualification Model show that the setup is accurate enough to characterize angular movements of the instrument components to an accuracy of ≈10 μrad. The qualification instrument is thermally stable to operate during all mission phases around Mercury proving that the transmitter and receiver sections will remain within the alignment requirements during its mission.

[DOTA]Somatostatin-14 analogs and their (111)In-radioligands: effects of decreasing ring-size on sst1-5 profile, stability and tumor targeting.

Multiple somatostatin receptor (sst)-subtype expression has been manifested in several human tumors. Hence, the availability of radiopeptides retaining the full pansomatostatin profile of the native hormone (SS14) is expected to increase the sensitivity and broaden the clinical indications of currently applied sst2-preferring cyclic octapeptide radioligands, like OctreoScan(®) ([(111)In-DTPA]octreotide). On the other hand, SS14 has been excluded from clinical use due to its rapid in vivo degradation. We herein present a small library of seven novel cyclic SS14-mimics carrying at their N-terminus the universal chelator DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) for stable binding of medically useful radiometals, like (111)In. By decreasing the number of amino acids composing the ring in their structure from 12 up to 6 AA, we induced important changes in key-biological parameters in vitro and in vivo. In particular, we observed unexpected changes and even total loss of sst1-5-affinity (6AA-ring), as well as weaker sst2-internalization efficacy as the ring size decreased. In contrast, in vivo stability increased with decreasing ring size, reaching its maximum in the 6AA-ring analogs. Interestingly, only the 12AA- and 9AA-ring members of this series showed sst2-specific uptake in AR4-2J tumors in mice revealing the prominent role of ring size on the biological response of tested SS14-derived radioligands.

Assessment of Intramedullary Spinal Pressure in Small Breed Dogs With Thoracolumbar Disk Extrusion Undergoing Hemilaminectomy

OBJECTIVE To assess intramedullary spinal pressure (IMP) in small breed dogs with thoracolumbar disk extrusion. STUDY DESIGN Prospective cohort study. ANIMALS Small breed dogs (n = 14) with thoracolumbar disk extrusion undergoing hemilaminectomy and healthy chondrodystrophic laboratory dogs (control; n = 3) without spinal disease. METHODS Diagnosis was based on clinical and neurological examinations and magnetic resonance imaging (MRI) and was confirmed intraoperatively. A standardized anesthesia protocol and surgical procedure were used to minimize factors that could influence IMP. Intramedullary pressure was measured through a minidurotomy at the site of spinal cord compression using a fiber optic catheter inserted perpendicular to the longitudinal axis of the spinal cord. Measurements were taken after hemilaminectomy and again after removal of extruded disk material. RESULTS Affected dogs had significantly higher IMP compared to control dogs (P = .008) and IMP decreased significantly post-decompression compared with initial values (P < .001). No correlation was found between IMP and neurologic grade, degree of spinal cord compression on MRI, or signal intensity changes on MRI. CONCLUSION Acute thoracolumbar disk extrusion is associated with increased IMP in small breed dogs and surgical decompression results in an immediate decrease of IMP.

Stability of Le Fort I maxillary inferior repositioning surgery with rigid internal fixation: a systematic review

The aim of this study was to evaluate the stability of Le Fort I maxillary inferior repositioning surgery in patients with a vertical maxillary deficiency at least 6 months after surgery. The electronic databases were searched to identify all articles reporting the long-term effects of one-piece maxillary inferior repositioning with rigid fixation. Methodological quality was evaluated according to 15 criteria related to study design, measurements, and statistical analysis. Two articles were identified, with a total of 22 patients. The maxilla was repositioned inferiorly from a mean 3.2 to 4.5mm in the anterior part and from a mean 0.1 to 1.8mm in the posterior part. At 6 months post-treatment, absolute relapse of a mean 1.6mm was measured for the anterior part of the maxilla and 0.3mm for the posterior part of the maxilla. The stability of maxillary inferior repositioning surgery could not be confirmed due to the small sample size, unclear diagnosis, and potential confounding factors.

Biochemical demonstration of complex formation of histone pre-mRNA with U7 small nuclear ribonucleoprotein and hairpin binding factors.

Histone RNA 3' end formation occurs through a specific cleavage reaction that requires, among other things, base-pairing interactions between a conserved spacer element in the pre-mRNA and the minor U7 snRNA present as U7 snRNP. An oligonucleotide complementary to the first 16 nucleotides of U7 RNA can be used to characterize U7 snRNPs from nuclear extracts by native gel electrophoresis. Using similar native gel techniques, we present direct biochemical evidence for a stable association between histone pre-mRNA and U7 snRNPs. Other complexes formed in the nuclear extract are dependent on the 5' cap structure and on the conserved hairpin element of histone pre-mRNA, respectively. However, in contrast to the U7-specific complex, their formation is not required for processing. Comparison of several authentic and mutant histone pre-mRNAs with different spacer sequences demonstrates that the formation and stability of the U7-specific complex closely follows the predicted stability of the potential RNA-RNA hybrid. However, this does not exclude a stabilization of the complex by U7 snRNP structural proteins.

Neighbourhood abundance and small-tree survival in a lowland Bornean rainforest

Conspecific effects of neighbours on small-tree survival may have a role in tree population dynamics and community composition of tropical forests. This notion was tested with data from two 4-ha plots in lowland forest at Danum, Sabah (Borneo), for a 21-year interval (censuses at 1986, 1996, 2001, 2007). Species with ≥45 focal trees 10 to <100 cm stem girth per plot in 1986 were selected. Logistic regressions fitted mean focal tree size and mean inverse-distance-weighted basal area abundance of neighbours (within 20 m), for the periods over which each focus tree was alive. Coefficients of variation of neighbourhood basal area abundance, both spatially and temporally, quantified the changing environment of each focus tree. Fits were critically and individually evaluated, with corrections for spatial autocorrelation. Conspecific effects at Danum was generally very weak or non-existent: species’ mortality rates varied also across plots. The main reasons appear to be that (1) species were not dense enough to interact despite frequent although weak spatial aggregation, and their neighbourhoods were highly differing in species composition; and (2) these neighbourhoods were highly variable temporally, meaning that focus trees experienced stochastically fluctuating neighbourhood environments. Only one species, Dimorphocalyx muricatus, showed strong conspecific effects (varying between plots) which can be explained by its distinct ecology. This understorey species is highly aggregated on ridges and is drought-tolerant. That this functionally and habitat-specialized species, has implied intraspecific density-dependent feedback in its dynamics is a remarkable indication of the overall processes maintaining stability of the Danum forest.

Temporal and small-scale spatial variation in grassland productivity, biomass quality, and nutrient limitation

Characterization of spatial and temporal variation in grassland productivity and nutrition is crucial for a comprehensive understanding of ecosystem function. Although within-site heterogeneity in soil and plant properties has been shown to be relevant for plant community stability, spatiotemporal variability in these factors is still understudied in temperate grasslands. Our study aimed to detect if soil characteristics and plant diversity could explain observed small-scale spatial and temporal variability in grassland productivity, biomass nutrient concentrations, and nutrient limitation. Therefore, we sampled 360 plots of 20 cm × 20 cm each at six consecutive dates in an unfertilized grassland in Southern Germany. Nutrient limitation was estimated using nutrient ratios in plant biomass. Absolute values of, and spatial variability in, productivity, biomass nutrient concentrations, and nutrient limitation were strongly associated with sampling date. In April, spatial heterogeneity was high and most plots showed phosphorous deficiency, while later in the season nitrogen was the major limiting nutrient. Additionally, a small significant positive association between plant diversity and biomass phosphorus concentrations was observed, but should be tested in more detail. We discuss how low biological activity e.g., of soil microbial organisms might have influenced observed heterogeneity of plant nutrition in early spring in combination with reduced active acquisition of soil resources by plants. These early-season conditions are particularly relevant for future studies as they differ substantially from more thoroughly studied later season conditions. Our study underlines the importance of considering small spatial scales and temporal variability to better elucidate mechanisms of ecosystem functioning and plant community assembly.

GCN5 maintains genome stability during development

The histone acetyltransferase, GCN5, is essential for survival of mice during embryogenesis. GCN5 null embryos die early during development due to increased apoptosis. We have demonstrated that the increased apoptosis in associated with increased p53 protein levels. Loss of p53 rescues the embryonic apoptosis in the GCN5 null embryos. These results raised the question of what molecular trigger leads to p53 stabilization and cell death in the absence of GCN5. p53 is generally referred to as the gatekeeper of the cell, monitoring cellular responses to DNA damage, genotoxic stress, and other unfavorable conditions in the cell. Therefore, we examined individual cells in wild type and mutant embryos for gross chromosomal aberrations that might trigger a genome integrity checkpoint. Karyotype analysis indicates that approximately 30% of the cells in an E8.5 GCN5 null embryo display chromosomal aberrations, predominantly chromosomal end adhesions and associations. In wild type E8.5 embryos, only 6% of the cells have chromosomal aberrations. Recent data using telomeric FISH demonstrates that cells from GCN5 null embryos have a decreased telomeric signal. Telomere maintenance is essential for maintaining genome integrity. Telomeric defects are associated with loss of chromosomes and chromosomal rearrangements that can lead to detrimental gene fusions involved in many types of cancers. Little is known about the chromatin structures present near the telomeric ends, or whether any of the telomere-associated proteins are subject to post-translational modification such as acetylation. Our results are the first data to demonstrate the involvement of a histone acetyltransferase, GCN5, in maintaining genome integrity through telomere maintenance and/or capping. ^

Stable carbon and oxygen isotope record of IODP Site 306-U1313, MIS 23-19

Since the seminal work by Hays et al. (1976), a plethora of studies has demonstrated a correlation between orbital variations and climatic change. However, information on how changes in orbital boundary conditions affected the frequency and amplitude of millennial-scale climate variability is still fragmentary. The Marine Isotope Stage (MIS) 19, an interglacial centred at around 785 ka, provides an opportunity to pursue this question and test the hypothesis that the long-term processes set up the boundary conditions within which the short-term processes operate. Similarly to the current interglacial, MIS 19 is characterised by a minimum of the 400-kyr eccentricity cycle, subdued amplitude of precessional changes, and small amplitude variations in insolation. Here we examine the record of climatic conditions during MIS 19 using high-resolution stable isotope records from benthic and planktonic foraminifera from a sedimentary sequence in the North Atlantic (Integrated Ocean Drilling Program Expedition 306, Site U1313) in order to assess the stability and duration of this interglacial, and evaluate the climate system's response in the millennial band to known orbitally induced insolation changes. Benthic and planktonic foraminiferal d18O values indicate relatively stable conditions during the peak warmth of MIS 19, but sea-surface and deep-water reconstructions start diverging during the transition towards the glacial MIS 18, when large, cold excursions disrupt the surface waters whereas low amplitude millennial scale fluctuations persist in the deep waters as recorded by the oxygen isotope signal. The glacial inception occurred at ~779 ka, in agreement with an increased abundance of tetra-unsaturated alkenones, reflecting the influence of icebergs and associated meltwater pulses and high-latitude waters at the study site. After having combined the new results with previous data from the same site, and using a variety of time series analysis techniques, we evaluate the evolution of millennial climate variability in response to changing orbital boundary conditions during the Early-Middle Pleistocene. Suborbital variability in both surface- and deep-water records is mainly concentrated at a period of ~11 kyr and, additionally, at ~5.8 and ~3.9 kyr in the deep ocean; these periods are equal to harmonics of precession band oscillations. The fact that the response at the 11 kyr period increased over the same interval during which the amplitude of the response to the precessional cycle increased supports the notion that most of the variance in the 11 kyr band in the sedimentary record is nonlinearly transferred from precession band oscillations. Considering that these periodicities are important features in the equatorial and intertropical insolation, these observations are in line with the view that the low-latitude regions play an important role in the response of the climate system to the astronomical forcing. We conclude that the effect of the orbitally induced insolation is of fundamental importance in regulating the timing and amplitude of millennial scale climate variability.

Evolution and breakup of viscous rotating drops

We study the evolution of a viscous fluid drop rotating about a fixed axis at constant angular velocity $Omega$ or constant angular momentum L surrounded by another viscous fluid. The problem is considered in the limit of large Ekman number and small Reynolds number. The analysis is carried out by combining asymptotic analysis and full numerical simulation by means of the boundary element method. We pay special attention to the stability/instability of equilibrium shapes and the possible formation of singularities representing a change in the topology of the fluid domain. When the evolution is at constant $Omega$, depending on its value, drops can take the form of a flat film whose thickness goes to zero in finite time or an elongated filament that extends indefinitely. When evolution takes place at constant L and axial symmetry is imposed, thin films surrounded by a toroidal rim can develop, but the film thickness does not vanish in finite time. When axial symmetry is not imposed and L is sufficiently large, drops break axial symmetry and, depending on the value of L, reach an equilibrium configuration with a 2-fold symmetry or break up into several drops with a 2- or 3-fold symmetry. The mechanism of breakup is also described

Numerical simulation of the evolution of viscous rotating drops

In this contribution we simulate numerically the evolution of a viscous fluid drop rotating about a fixed axis at constant angular velocity ? or constant angular momentum L, surrounded by another viscous fluid. The problem is considered in the limit of large Ekman number and small Reynolds number. In the lecture we will describe the numerical method we have used to solve the PDE system that describes the evolution of the drop (3D boundary element method). We will also present the results we have obtained, paying special attention to the stability/instability of the equilibrium shapes.

Floating zone stability

The present state of de preparation of an experiment on floating liquid zones to be performed in the first Spacelab flight is presented. In this experiment,a liquid bridge is to be placed between two parallel coaxial disks (in the Fluid Physics Module)and subjected to very precise disturbances in order to check the theoretical predictions about its stability limits and behavior under mechanical inputs: stretching of the zone, filling or removing the liquid,axial vibration, rotation, disalignment, etc. Several aspects of the research are introduced:1) Relevance of the study. 2) Theoretical predictions of the liquid behavior regarding the floating-zone stability limits and the expected response to vibrational and rotational disturbances. 3) Ground support experiments using the Plateau technique or the small scale simulation. 4) Instrumental aspects of the experimentation: the Fluid Physics Module utilization and post-flight data analysis.5)Research program for future flights.

Optimizing prolog for small devices: A case study

In this paper we present the design and implementation of a wearable application in Prolog. The application program is a "sound spatializer." Given an audio signal and real time data from a head-mounted compass, a signal is generated for stereo headphones that will appear to come from a position in space. We describe high-level and low-level optimizations and transformations that have been applied in order to fit this application on the wearable device. The end application operates comfortably in real-time on a wearable computer, and has a memory foot print that remains constant over time enabling it to run on continuous audio streams. Comparison with a version hand-written in C shows that the C version is no more than 20-40% faster; a small price to pay for a high level description.